Analysis on Thermal Runaway Propagation Characteristics and Efficacy of Water Sprinkler System in Shelf Storage of 46120 Ternary Lithium Batteries

Analysis on Thermal Runaway Propagation Characteristics and Efficacy of Water Sprinkler System in Shelf Storage of 46120 Ternary Lithium Batteries | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Analysis on Thermal Runaway Propagation Characteristics and Efficacy of Water Sprinkler System in Shelf Storage of 46120 Ternary Lithium Batteries Xiaojie Liu, Wenhai Zhang, Menglin Yang, Xinyu Yang, Zhenyu Zhang, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8995646/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 9 You are reading this latest preprint version Abstract Taking the 46120 cylindrical ternary lithium-ion battery as the research object, A full-scale experimental setup with 512 cells was designed to evaluate TR behavior under varying conditions, including TR initiation positions (upper tray edge, lower tray edge, lower tray center), sprinkler arrangements (top-spray, side-spray), and shelf layouts (double-layer, single-layer). The experimental results show that the TR propagation is highly dependent on cell location, and under the same case, the vertical propagation speed (7.7×10 − 5 m/s) is significantly higher than the horizontal(5.5×10 − 5 m/s). In different sprinkler layout configuration, the top-spray sprinkler arrangement has suppression efficiency with 1-seconds response time, outperforming side-spray sprinkler, which failed to trigger sprinkler response. After the optimization of the shelf layout, the sprinkler trigger time is shortened by 89.8% and 97.6% for edge and center TR positions, respectively, while the efficiency of the sprinkler system is improved by 99.6% and 95.2%. This study provides critical data for optimizing fire protection systems in lithium-ion battery storage facilities, and has reference significance for the storage safety of lithium-ion batteries. lithium-ion batteries Shelf storage Thermal runaway propagation Efficacy of sprinkler system Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Highlights • Novel insights into thermal runaway (TR) propagation and sprinkler system efficacy in lithium-ion battery warehouse storage scenarios. • Quantitative evaluation model for sprinkler system performance, integrating response matching degree and resource utilization efficiency. • Vertical TR propagation rate(7.7×10m/s) exceeds horizontal propagation rate(5.5×10 m/s), strongly influenced by cell location and venting direction. • Top-spray sprinkler systems outperform side-spray configurations, and single-layer shelf layouts significantly enhance fire suppression efficiency compared to double-layer designs. 1. Introduction The global shift toward electric vehicles (EVs) under the "dual carbon" initiative has escalated the demand for lithium-ion batteries (LIBs), with projected installed capacity exceeding 500 GW by 2033 [ 1 , 2 ] . However, the manufacturing process of lithium-ion batteries is complex. To facilitate the full reaction between active materials and electrolyte [ 3 , 4 ] , the cells are subjected to a period of resting after electrolyte injection and formation [ 5 – 7 ] . Despite their widespread adoption, LIBs pose significant safety risks during manufacturing and storage, particularly due to thermal runaway (TR) triggered by process deviations or mechanical impacts [ 8 , 9 ] . While material enhancements [ 10 , 11 ] and applying external thermal management systems [ 12 – 14 ] mitigate some risks, fire suppression remains a critical challenge. Studies on lithium battery fire extinguishing have been carried out by many scholars at home and abroad [ 15 – 20 ] . Sun et al. [ 21 ] investigated the suppression effects of HFC-227ea (heptafluoropropane fire extinguishing agent), C6F12O (perfluorohexanone) and water on TR of lithium-ion batteries. The results showed that water had the best cooling effect and could suppress the propagation of TR, and C6F12O could reduce the battery temperature but failed to suppress TR propagation, and HFC-227ea had the poorest effect. When water is atomized into water mist, its surface area increases under the same volume, thereby enhancing the heat exchange capacity [ 22 ] . Lou et al. [ 23 ] studied the influence of water mist on fires in energy storage power stations, and the results indicated that the suppression effect of the water mist fire extinguishing system was positively correlated with the spray flow rate, spray cone angle and nozzle flow velocity of the water mist. The fire-extinguishing efficiency of water mist can be further improved by adding physical or chemical reagents. Wang et al. [ 24 ] proposed a novel fire-extinguishing method using a new type of composite additive compatible with water mist, and found that both physical and chemical additives played a significant role in fire extinguishing, which was more effective than pure water mist. In addition, many scholars have dedicated themselves to researching new and highly efficient fire extinguishing agents [ 25 – 28 ] . Li et al. [ 26 ] proposed a dry powder fire extinguishing agent compounded with inorganic phase change materials, the results showed that the composite dry powder fire extinguishing agent can not only effectively extinguish fires but also suppress the propagation of TR. Zhou et al. [ 29 ] developed a gel-type foam fire extinguishing agent, and the results indicated that the fire extinguishing time of the gel-protein foam fire extinguishing agent was reduced by 71.43% compared with that without any fire extinguishing agent. Deng et al. [ 30 ] studied the TR suppress ability and cooling effect of three different nanofluid sprays (boron nitride, aluminum oxide, and titanium dioxide) on lithium-ion batteries, the results showed that nanofluid sprays have a stronger cooling effect than water mist. Currently, many research focus in the field of lithium-ion battery TR has mostly centered on fire extinguishing agent types and additive modification, with insufficient attention paid to the practical application scenarios. In particular, this study systematically investigates the TR propagation characteristics of lithium batteries in warehouse environments and the efficacy of automatic sprinkler systems, aiming to provide a reference for optimizing the prevention and control system of lithium battery fires in complex warehouse scenarios. 2. Material and Methods 2.1 Experimental System A full-scale fire-extinguishing platform was constructed, with featuring flame-retardant battery shelves, heating devices, thermocouples, and real-time monitoring systems, as shown in Fig. 1 . 2.2 Experimental Materials and Equipment The 46120 cylindrical ternary lithium battery was selected as the research object, with a single cell dimension of 46mm in diameter and 120mm in height. The state of charge (SOC) of the cells was 53%, consistent with the actual SOC of cells in factory storage. The shelves were constructed according to the static storage shelves currently used in lithium battery factories, with a layer height of 750mm and a single shelf height of 375mm. To facilitate easier activation of the sprinkler system, the response temperature of the sprinklers was set to 68℃, and a sufficiently large flow rate was selected to ensure rapid cooling of the cell surfaces and suppression of open flames. Therefore, K161 and K80 sprinkler were used in the system. The experimental materials used are listed in Table 1 . The equipment used in the experiment include cameras, DC regulated power supplies, data acquisition systems, and thermocouples, among others. With reference to GB38031-2025 Safety Requirements for Traction Batteries of Electric Vehicles , the power of the heating sheet used in the experiment was set to 300W [ 31 ] .Other materials such as Teflon tape, insulating tape, and connecting wires are all standard products. 2.3 Experimental Methods 2.3.1 Experimental Scheme Prior to the experiment, the state of charge (SOC) of the cells was ensured to be 53%. The horizontal spacing between cells was 8mm, and the vertical spacing was 12mm. Through investigating different heating positions (upper tray edge, lower tray edge, lower tray center), different sprinkler arrangement (top-spray, side-spray), and different shelf configuration layouts s (double-layer, single-layer), this study systematically explored the TR propagation rate, as well as the response and fire-extinguishing effect of the sprinkler system. The specific experimental schemes are as follows: To study the TR propagation behavior of under different heating cell positions, temperature measurement points are arranged in Cases A, B, and C. Figure 3 shows the thermocouple layouts under different cases. 2.3.2 Calculation of TR Propagation Rate The TR propagation rate is one of the key parameters for evaluating the risk level of battery pack [ 32 ] , which can be calculated based on the time interval and spatial distance between TR events of adjacent cells [ 33 ] . $$\text{V}\text{=}\frac{\text{L}}{\text{∆}\text{t}}$$ 1 Where, L is the distance between two adjacent cells, in m; \(\text{∆}\text{t}\text{}\) is the time interval from thermal runaway of the previous cell to TR of the next cell, in s; V is in m/s. The horizontal and vertical propagation processes of TR are shown in the following figure: The horizontal spacing between two adjacent cells in shelf storage is 8×10⁻³m, and the vertical spacing is 1.2×10⁻³m. The horizontal and vertical propagation speeds of TR directly reflect the diffusion rate of TR in different directions of the battery pack. 2.3.3 Calculation Method for Sprinkler System Efficacy (1) Response matching degree The sprinkler response matching degree is an indicator to evaluate the adaptability between the response capability of the automatic fire extinguishing system and the fire scenario. Assume that the time from TR of the first cell in the battery pack to the start of sprinkler is \(\text{∆}{\text{t}}_{\text{1}}\) , the number of cells with TR propagation is n, and the time from TR of the nth cell to triggering the sprinklers is the fastest response time that the sprinklers can achieve, denoted as \(\text{∆}{\text{t}}_{\text{o}}\) . The response matching degree can be expressed as: $$\text{R}\text{=}\frac{\text{∆}{\text{t}}_{\text{o}}}{\text{∆}{\text{t}}_{\text{1}}}\text{·100%}$$ 2 The response matching degree can quantify the gap between the actual response speed and the theoretical optimal speed. When \(\text{∆}{\text{t}}_{\text{1}}\) is close to \(\text{∆}{\text{t}}_{\text{o}}\) , the ratio is large, indicating timely response, which can effectively suppress TR propagation; conversely, if \(\text{∆}{\text{t}}_{\text{1}}\) is much larger than \(\text{∆}{\text{t}}_{\text{o}}\) , the ratio approaches 0, indicating delayed response and large-scale spread of TR. (2) Fire-extinguishing water consumption Water consumption is one of the important parameters for evaluating the fire-extinguishing effect of sprinkler systems [ 34 ] . It is calculated as the product of its operating time and the flow rate [ 35 ] . $${\text{Q}}_{\text{w}}\text{=}\text{Q}\text{·}\text{∆}{\text{t}}_{\text{s}}$$ 3 Where, Q is the sprinkler flow rate, in L/min; \(\text{∆}{\text{t}}_{\text{s}}\) is the time from sprinkler activation to complete extinction of open flames in the shelf. In top-spray Case(Case A,B,C,G,H), the number of sprinkler is one with a flow rate of 322 L/min. In side-spray Case(Case D,F), the number of sprinkler is four, with a total flow rate of 640 L/min. (3) Benchmark water consumption Assume that the sprinklers are turned on immediately after TR of the first cell, and the sprinklers directly act on the TR cell. The minimum water consumption required from sprinkler activation to complete extinction of flames is the benchmark water consumption, denoted as \({\text{Q}}_{\text{0}}\) . Benchmark water consumption is the core benchmark parameter of the resource utilization efficiency indicator in the evaluation of f efficiency of sprinkler system. It is measured through experiments that \({\text{}\text{Q}}_{\text{0}}\) is approximately 80L. (4) Resource utilization efficiency Resource utilization efficiency is an indicator to measure the effective utilization degree of water resources in the fire-extinguishing process, reflecting the rationality of system design, scientificity of operation, and water-saving level. Its core is the ratio of theoretical water consumption to actual water consumption, i.e.: $$\eta\text{=}\frac{{\text{Q}}_{\text{0}}}{{\text{Q}}_{\text{w}}}\text{·100%}$$ 4 In the actual fire-extinguishing process, the closer is to \({\text{Q}}_{\text{0}}\) , the closer the system is to the ideal state in water consumption control, with less resource waste; conversely, the larger the difference between and \({\text{Q}}_{\text{0}}\) , the farther the actual water consumption deviates from the theoretical optimal value, and the lower the resource utilization efficiency. A higher utilization efficiency indicates less water waste and better efficiency of sprinkler system. (5) Efficiency of water sprinkler system Efficiency is the core indicator to measure whether the sprinkler system is efficient. The efficiency of the sprinkler system is comprehensively evaluated by the response matching degree and resource utilization efficiency. Denote the efficiency of the sprinkler system as E , then E can be expressed as: $$\text{E}\text{=}\text{R}\text{·}\eta\text{·100%}$$ 5 3. Results 3.1 Analysis of TR Risk and Efficiency of Water Sprinkler System at Different Positions in the Shelf 3.1.1 TR Propagation under Different Heating Positions From Fig. 4 (a), under Condition A, the safety valve of the heated cell opened at 344 seconds, and the temperature rise rate exceeded 1℃/s at approximately 351 seconds, indicating that the cell underwent TR. From Fig. 4 (b), it is observed that the surface temperatures of all cells except the heated one were below 40℃. Although the surface temperature rise rate of some cells exceeded 1℃/s, this was caused by the flames generated from the combustion and explosion of the heated cell after TR coming into contact with their surfaces. Post-experiment observations confirmed that only the heated cell experienced TR. The sprinkler system did not activate under Condition A, and the same result was observed in three repeated experiments. From Fig. 5 (a) and (b), two cells underwent TR under Condition B. At 287 seconds after the TR of the heated cell, its left-side cell occured TR. The sprinkler system was activated 3 seconds later, and the flame was completely extinguished after 18s of sprinkler action. It can be observed from Fig. 6 (c) that the temperatures of the remaining cells did not exceed 30℃, with no risk of TR. Lateral propagation of TR occurred under Condition B. From Fig. 6 (a) and (b), three cells underwent TR under Condition C. At 145 seconds after the TR of the heated cell, its adjacent cell experienced TR. After another 11 seconds, the cell directly below the heated cell occured TR. The sprinkler system was activated 1 seconds later, and the flame was completely extinguished after 45 seconds of sprinkler action. Under Condition C, TR propagated in both horizontal and vertical directions. Table 4 . lists the horizontal and vertical propagation times of battery TR under different cases. It is worth noting that in Case C, although TR spreads to the lower layer cell 11 seconds after TR of the second cell, but vertical propagation is affected by the synergistic heating of the first and second TR cells. Therefore, when calculating the TR propagation speed, the propagation time is the time from TR of the first cell to the third cell. Table 4 Number of TR cells and horizontal&vertical propagation times under different heating positions Test Case Number of TR cells Horizontal propagation time of TR (s) Vertical propagation time of TR (s) A 1 / / B 2 287 / C 3 145 157 Figure 7 . shows the horizontal and vertical propagation speeds of TR cell under different cases. It can be seen from Fig. 7 . that in Case B, TR of cells propagates horizontally with a propagation speed of 2.8×10⁻⁵m/s; in Case C, cells propagate in both horizontal and vertical directions, with a horizontal TR propagation speed of 5.5×10⁻⁵m/s and a vertical propagation speed of 7.7×10⁻⁵m/s. The vertical propagation speed of cells is faster, 28.6% faster than the horizontal one.This is because the cell's safety valve is located at the bottom, after the valve opens, pressure is released downward, and the energy release direction is mainly downward, leading to faster propagation of TR. 3.1.2 Efficiency of Sprinkler System under Different TR Positions Table 5 . calculates various performance parameters of the fire-extinguishing system after TR of cells at different positions. As shown in Table 5 ., Condition B consumes less water, which is because fewer cells occur TR, simplifying suppression efforts. In contrast, the sprinkler system in Condition C responds faster, which is determined by the movement regularity of flue gas [ 36 ] : after TR occurs in the lower tray cells, the flue gas moves vertically upward under the drive of thermal buoyancy. However, in Condition A, after TR occurs in the edge cells, the flames and flue gas mainly gather at the lower edge due to the blocking of the upper tray, and the upper sprinklers do not reach the activation temperature. Therefore, for top-spray systems, the sprinkler activation is slower when TR occurs in edge cells. Table 5 Performance parameters of sprinkler system after TR of cells at different positions Test Case Sprinkler flow rate \(\text{∆}{\text{t}}_{\text{1}}\) (s) \(\text{∆}{\text{t}}_{\text{o}}\) (s) Water consumption (L) R (%) η (%) E (%) A 322L/min / / / / / 0 B 322L/min 290 3 96.6 1.03 82.81 0.86 C 322L/min 157 1 241.5 0.64 33.13 0.21 Figure 8 . shows the response matching degree, resource utilization efficiency, and efficiency of the sprinkler system under different cases. It can be seen from Fig. 9 . that the response matching degrees of the sprinkler system under different cases are 0%, 1.04%, and 0.64% respectively; the resource utilization efficiency are 0%, 82.81%, and 33.13% respectively; the efficiencies are 0%, 0.86%, and 0.21% respectively. The efficiency of the sprinkler system in Case B is higher, which is approximately 75.6% higher than that in Case C. Therefore, under the top-spray scheme, when TR occurs in the center cell of the lower tray, the sprinkler system can exert greater efficiency, with highest resource utilization efficiency. 3.2 Efficiency of Sprinkler System under Different Sprinkler Arrangements Based on the analysis in Section 2 , it is found that for top-spray systems, the sprinkler system exhibits lower efficacy when TR occurs in inner edge cells. Therefore, the top-spray system was replaced with a side-spray system. Experimental results show that the sprinklers did not activate under Conditions D and F, even after three repeated experiments for each condition, the sprinklers still failed to activate. In addition to the influence of flue gas movement regularity, this phenomenon is also related to the cell structure. During TR of cells, their internal temperature rises sharply, and high-temperature ejecta are ejected from the pressure relief valve. The sprinkler heads of top-spray systems, which are directly facing the top space of the shelves, can respond more quickly to high-temperature signals at the top. In contrast, side-spray systems may be blocked by shelf laminates or battery trays, failing to sense the high temperature at the top in a timely manner and unable to effectively capture hot flue gas, resulting in activation delay. 3.3 Efficiency of Sprinkler System under Different Shelf Layouts From the comparison between the top-spray and side-spray schemes in the previous section, it is found that the top-spray is more likely to activate the sprinkler. Based on this, the shelf layout were optimized: the double-layer shelf was changed to a single-layer one, and two working conditions were set, i.e., TR of cells at the inner edge and those at the centre position. It can be seen from the experimental videos that there was no propagation of TR in Conditions G and H, and the sprinkler system could be activated immediately after the TR of the first cell. In Condition G, the sprinkler system was activated 16 seconds after the cell's TR, and the flame was extinguished 32 seconds after the sprinkler was activated. In Condition H, the sprinkler system was activated 7 seconds after the cell's TR, and the flame was extinguished 83 seconds. Table 6 . calculates various performance parameters of the sprinkler system under different shelf layouts. Table 6 Performance parameters of sprinkler system under different shelf layouts Test Case Sprinkler flow rate \(\text{∆}{\text{t}}_{\text{1}}\) (s) \(\text{∆}{\text{t}}_{\text{o}}\) (s) Water consumption (L) R (%) η (%) E (%) B 322L/min 290 3 96.6 1.03 82.81 0.86 C 322L/min 157 1 241.5 0.64 33.13 0.21 G 322L/min 16 16 170.7 100 46.87 46.87 H 322L/min 7 7 442.7 100 18.07 18.07 From Fig. 9 ., in Condition B, the E value is 0.86%, which is at a moderately low level among all conditions, however, the lower water consumption alleviates the insufficient efficacy to a certain extent. In Condition C, the actual response of the sprinkler is also delayed, and the propagation range of TR may expand due to the delay, with the corresponding E value being only 0.21%, the lowest among all conditions. Condition G shows the most prominent performance: the sprinkler responds quickly, can intervene rapidly in the early stage of TR, and has high resource utilization efficiency, with an E value as high as 46.87%, indicating the optimal comprehensive efficacy. The response time of Condition H is significantly shorter than that of Conditions B, C, and G, but its water consumption is relatively high. This is because the sprinkler heads are close to the trays, resulting in a spraying blind area directly below them, and the corresponding E value is 18.07%. Overall, the optimized shelf layout and sprinkler system have better efficiency. After TR of the inner edge cell, compared with Cases C and G, the response time of the optimized sprinkler system is shortened by 89.8%, and the efficiency of the sprinkler system is improved by 99.6%; after TR of the center cell, compared with Cases B and H, the response time of the optimized sprinkler system is shortened by 97.6%, and the efficiency of the sprinkler system is improved by 95.2%. 4. Conclusions (1) TR propagation in the shelf is strongly correlated with the location of the TR cell, and TR propagation is directionally asymmetric, with vertical speeds 28.6% faster than horizontal speeds. TR of the center cell of the lower tray only propagates horizontally (speed 2.8×10⁻⁵m/s), while TR of the edge cell is limited by the structure with no obvious spread. This difference stems from the synergistic effect of cell arrangement density, pressure relief direction, and heat accumulation path. (2) Top-spray systems are optimal for warehouse applications, aligning with flue gas dynamics. The top-spray sprinkler arrangement has exhibits superior suppression efficiency with a 1-second response time, outperforming side-spray sprinkler, which failed to trigger sprinkler response. Its advantage lies in matching the vertical upward characteristics of flue gas, which can quickly trigger the sprinkler through high-temperature flue gas. The side-spray system is not suitable for densely stored shelves because it is shielded by shelves and cannot effectively capture hot flue gas. (3) The optimized shelf layout significantly improves the efficiency of sprinkler system. After changing the double-layer shelf to a single-layer one, the sprinkler activation time is shortened from 290 seconds to 7–16 seconds (optimized Conditions H and G), and the efficacy ( E value) is increased to 18.07%-46.87%. In cases where TR occurs in the inner edge cells and middle cells, the response time of the optimized sprinkler system is shortened by 89.8% and 97.6% respectively, and the efficacy is improved by 99.6% and 95.2% respectively. (4) The efficacy of the sprinkler system can be evaluated through the dual dimensions of "response matching degree - resource utilization efficiency". The proposed evaluation model (response matching degree × resource efficiency) effectively quantifies system performance. In the optimized Condition G, ∆ t ₁ (16 seconds) perfectly matches ∆ t ₀ (16 seconds) with reasonable water consumption control, thus achieving the optimal efficacy. In contrast, in the unoptimized Condition C, since ∆ t ₁ (157 seconds) is much longer than ∆ t ₀ (1 seconds) and the water consumption is as high as 241.5L, the efficacy is only 0.21%. This work advances LIB storage safety by integrating empirical TR data with fire suppression optimization, offering a framework for future industrial standards. Declarations Author Contribution "[X.L.] and [Y.S.] conceived and designed the analysis. [W.Z.] collected the data. [M.Y.] and [X.Y.] performed the analysis. [Z.Z.] and [Y.S.] contributed to the interpretation of the results. [X.L.] wrote the first draft of the manuscript. All authors reviewed, edited, and approved the final version of the manuscript." References MAMMACıOĞLU O (2025) A new experimental approach to lithium-ion battery fires in electric vehicles: Investigation of fire behavior and effectiveness of extinguishing agents [J]. Case Stud Therm Eng 73:106554. .doi.org/https://doi.org/10.1016/j.csite.2025.106554 DIOHA M O, LUKUYU J, VIRGüEZ E et al (2022) Guiding the deployment of electric vehicles in the developing world [J]. 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J Energy Storage 131:117520. .doi.org/https://doi.org/10.1016/j.est.2025.117520 ZHANG J, FAN T, YUAN S et al (2024) Patent-based technological developments and surfactants application of lithium-ion batteries fire-extinguishing agent [J]. J Energy Chem 88:39–63. doi.org/https://doi.org/10.1016/j.jechem.2023.08.037 ZHOU G, LI Y, LIU Y et al (2025) Preparation of environment-friendly gel-protein foam and its fire suppression performance for lithium-ion batteries [J]. Fuel 384:133979. doi.org/https://doi.org/10.1016/j.fuel.2024.133979 DENG J, HU Z, CHEN J et al (2025) The enhanced cooling effect and critical control capability of nanofluids on suppressing thermal runaway of lithium-ion batteries [J]. J Energy Storage 106:114733. .doi.org/https://doi.org/10.1016/j.est.2024.114733 HE F, DENG J, WANG H et al (2025) Fire propagation and suppression in multi-layer battery systems [J]. Appl Therm Eng 276:126945. doi.org/https://doi.org/10.1016/j.applthermaleng.2025.126945 XU Y, LU J, ZHANG P et al (2025) Thermal runaway and flame propagation of lithium-ion battery in confined spaces: Experiments and simulations [J]. J Energy Storage 117:116154. doi.org/https://doi.org/10.1016/j.est.2025.116154 YUAN S, LAI Q, DUAN X et al (2023) Carbon-based materials as anode materials for lithium-ion batteries and lithium-ion capacitors: A review [J]. J Energy Storage 61:106716. .doi.org/https://doi.org/10.1016/j.est.2023.106716 YAO Z, YIN R (2025) A review on thermal management system and employed biomimetic technology to enhance lithium-ion battery packs for electric vehicles [J]. J Energy Storage 111:115399. .doi.org/https://doi.org/10.1016/j.est.2025.115399 XU C, ZHANG F, FENG X et al (2021) Experimental study on thermal runaway propagation of lithium-ion battery modules with different parallel-series hybrid connections [J]. J Clean Prod 284:124749. .doi.org/https://doi.org/10.1016/j.jclepro.2020.124749 WANG Z, YANG H, LI Y et al (2019) Thermal runaway and fire behaviors of large-scale lithium ion batteries with different heating methods [J]. J Hazard Mater 379:120730. doi.org/https://doi.org/10.1016/j.jhazmat.2019.06.007 Tables Tables 1 to 3 are available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files Tables1to3.docx Cite Share Download PDF Status: Under Revision Version 1 posted Editorial decision: Revision requested 02 Apr, 2026 Reviews received at journal 02 Apr, 2026 Reviews received at journal 20 Mar, 2026 Reviewers agreed at journal 10 Mar, 2026 Reviewers agreed at journal 06 Mar, 2026 Reviewers invited by journal 05 Mar, 2026 Editor assigned by journal 05 Mar, 2026 Submission checks completed at journal 04 Mar, 2026 First submitted to journal 28 Feb, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8995646","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":602017361,"identity":"c32681d4-77c3-4f7a-a244-94fbf00744fd","order_by":0,"name":"Xiaojie Liu","email":"","orcid":"","institution":"Key Laboratory of Personnel Safety in Disaster Environments, Anhui Province，Hefei Institute for Public Safety Research, Tsinghua University","correspondingAuthor":false,"prefix":"","firstName":"Xiaojie","middleName":"","lastName":"Liu","suffix":""},{"id":602017362,"identity":"ae3578d4-d661-4be7-8ccb-7151f8991f05","order_by":1,"name":"Wenhai Zhang","email":"","orcid":"","institution":"Automotive Energy Supply Corporation Group Ltd","correspondingAuthor":false,"prefix":"","firstName":"Wenhai","middleName":"","lastName":"Zhang","suffix":""},{"id":602017363,"identity":"501fceb1-61cd-49c6-9810-6ee2d3f03ebe","order_by":2,"name":"Menglin Yang","email":"","orcid":"","institution":"Automotive Energy Supply Corporation Group Ltd","correspondingAuthor":false,"prefix":"","firstName":"Menglin","middleName":"","lastName":"Yang","suffix":""},{"id":602017364,"identity":"f9639a3f-4f4a-4b3e-9b63-4db92ac1037b","order_by":3,"name":"Xinyu Yang","email":"","orcid":"","institution":"Key Laboratory of Personnel Safety in Disaster Environments, Anhui Province，Hefei Institute for Public Safety Research, Tsinghua University","correspondingAuthor":false,"prefix":"","firstName":"Xinyu","middleName":"","lastName":"Yang","suffix":""},{"id":602017365,"identity":"cd0261b8-9758-40b6-86c0-6afb731d42e0","order_by":4,"name":"Zhenyu Zhang","email":"","orcid":"","institution":"Key Laboratory of Personnel Safety in Disaster Environments, Anhui Province，Hefei Institute for Public Safety Research, Tsinghua University","correspondingAuthor":false,"prefix":"","firstName":"Zhenyu","middleName":"","lastName":"Zhang","suffix":""},{"id":602017366,"identity":"32ed6c31-5b1e-4a34-9a70-926b3bb3bf2d","order_by":5,"name":"Yuhan Song","email":"","orcid":"","institution":"Key Laboratory of Personnel Safety in Disaster Environments, Anhui Province，Hefei Institute for Public Safety Research, Tsinghua University","correspondingAuthor":false,"prefix":"","firstName":"Yuhan","middleName":"","lastName":"Song","suffix":""},{"id":602017367,"identity":"e8567b3c-7001-40e8-a653-8917f7c12e04","order_by":6,"name":"Xiaoyong Liu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABOElEQVRIie3RsWrCUBSA4XMJJEto1iNSfYUTAuIgSJ+jSy5CXEIRBCm0lExx0bpGKPgKSqE4RgSndC0ZOsSlU4dMRSEtTSJFqUm7FpqfcO4h5IPABSgq+oOdCPHQdzsLADB9gFmV/ftviQdEIHdPtHxyuKObHL8SSa5hcN3go3L/6SqM6hfV84EasjmBIpkE23nGj8ka6SuDj++8nr+wsas+exoyj6A0eCU29LKIGujikk990/AXFvKZY1L53Y6AfJMEZmcRcvWPHem4UUq0DbMJmvlEDbidkPYKXBH5BM0aJoQwj4hd4reGNnZMAR9t5FM0evWYyOi9dBbDY6Ioy4fS5q1xOsL2OryMbvjEad37Mako/dYs2B6Tr84skCnd4vtMk5Ph5gKAJoAUpFvV+uGzoqKion/ZJ/ZJa05AuGbTAAAAAElFTkSuQmCC","orcid":"","institution":"Key Laboratory of Personnel Safety in Disaster Environments, Anhui Province，Hefei Institute for Public Safety Research, Tsinghua University","correspondingAuthor":true,"prefix":"","firstName":"Xiaoyong","middleName":"","lastName":"Liu","suffix":""}],"badges":[],"createdAt":"2026-02-28 13:23:44","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8995646/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8995646/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":104343604,"identity":"51645d24-154d-4d19-ad11-ab0a9dee99a5","added_by":"auto","created_at":"2026-03-10 17:13:47","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":89959,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic diagram of the experimental system\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8995646/v1/fd75782ec172216825c6c9db.jpg"},{"id":104343612,"identity":"f71f9d48-ebdc-4de4-a7a6-0f776342ae09","added_by":"auto","created_at":"2026-03-10 17:13:48","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":366545,"visible":true,"origin":"","legend":"\u003cp\u003eHeating cell positions and thermocouple layouts under different cases\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8995646/v1/2a2447378174670b64028af3.jpg"},{"id":104779671,"identity":"eef46844-720c-4c84-b87e-98af356e63dd","added_by":"auto","created_at":"2026-03-17 07:44:14","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":45949,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic diagram of TR propagation process\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8995646/v1/0b2c428a34882b867aad0821.jpg"},{"id":104405651,"identity":"bfe8b47c-e0ee-4b71-a090-f73e6d2bd915","added_by":"auto","created_at":"2026-03-11 12:23:33","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":102945,"visible":true,"origin":"","legend":"\u003cp\u003eTemperature and temperature rise rate changes of cells in Case A (a) Temperature change and temperature rise rate of the heated cell; (b) Temperature change of other cells\u003c/p\u003e","description":"","filename":"4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8995646/v1/eb44e9989fd4b287ada9a0d9.jpg"},{"id":104405793,"identity":"d7f90a0f-02b9-41c7-b3f0-f5ae859ef8c2","added_by":"auto","created_at":"2026-03-11 12:23:51","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":105843,"visible":true,"origin":"","legend":"\u003cp\u003eTemperature and temperature rise rate changes of cells in Case B (a) Temperature change of TR cells; (b) Temperature rise rate of TR cells; (c) Temperature change of other cells\u003c/p\u003e","description":"","filename":"5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8995646/v1/c45ea4ee06784babfbafb611.jpg"},{"id":104343605,"identity":"280479e8-6fe3-41c8-aca6-71058b9f32e7","added_by":"auto","created_at":"2026-03-10 17:13:47","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":118576,"visible":true,"origin":"","legend":"\u003cp\u003eTemperature and temperature rise rate changes of cells in Case C (a) Temperature change of TR cells; (b) Temperature rise rate of TR cells; (c) Temperature change of other cells\u003c/p\u003e","description":"","filename":"6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8995646/v1/28b5421271894e5ab35c4f5a.jpg"},{"id":104343607,"identity":"f604aaf4-7bfa-4e0e-bf7d-54201ceba272","added_by":"auto","created_at":"2026-03-10 17:13:47","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":40940,"visible":true,"origin":"","legend":"\u003cp\u003eTR propagation rates of cells under different cases\u003c/p\u003e","description":"","filename":"7.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8995646/v1/3eef7104d9d69622eb6dc12a.jpg"},{"id":104779794,"identity":"fa1a4a08-8b7c-4d41-a44d-5ed49af71f6f","added_by":"auto","created_at":"2026-03-17 07:46:28","extension":"jpg","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":34936,"visible":true,"origin":"","legend":"\u003cp\u003eResponse matching degree, resource utilization efficiency, and efficiency of sprinkler system under different cases\u003c/p\u003e","description":"","filename":"8.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8995646/v1/a6dac536a5c898f2be1e56c4.jpg"},{"id":104343613,"identity":"e33c5876-be42-4cf0-bce7-32219bbf1669","added_by":"auto","created_at":"2026-03-10 17:13:48","extension":"jpg","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":57131,"visible":true,"origin":"","legend":"\u003cp\u003eResponse matching degree, resource utilization efficiency, and efficiency of fire protection system under different shelf layouts\u003c/p\u003e","description":"","filename":"9.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8995646/v1/e0744585e12fc42fd8b31b9a.jpg"},{"id":104785476,"identity":"cfa9a215-6a28-4a23-bf16-bd8677fd37be","added_by":"auto","created_at":"2026-03-17 08:11:34","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1755444,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8995646/v1/6f251a12-718b-4794-ace3-2358d2e8d926.pdf"},{"id":104343610,"identity":"9052abd3-07eb-42ce-ab1e-504de495a6c7","added_by":"auto","created_at":"2026-03-10 17:13:48","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":1586382,"visible":true,"origin":"","legend":"","description":"","filename":"Tables1to3.docx","url":"https://assets-eu.researchsquare.com/files/rs-8995646/v1/cda1c2095dd3023bfdb775a3.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Analysis on Thermal Runaway Propagation Characteristics and Efficacy of Water Sprinkler System in Shelf Storage of 46120 Ternary Lithium Batteries","fulltext":[{"header":"Highlights","content":"\u003cp\u003e\u0026bull; Novel insights into thermal runaway (TR) propagation and sprinkler system efficacy in lithium-ion battery warehouse storage scenarios.\u003c/p\u003e\u003cp\u003e\u0026bull; Quantitative evaluation model for sprinkler system performance, integrating response matching degree and resource utilization efficiency.\u003c/p\u003e\u003cp\u003e\u0026bull; Vertical TR propagation rate(7.7\u0026times;10m/s) exceeds horizontal propagation rate(5.5\u0026times;10 m/s), strongly influenced by cell location and venting direction.\u003c/p\u003e\u003cp\u003e\u0026bull; Top-spray sprinkler systems outperform side-spray configurations, and single-layer shelf layouts significantly enhance fire suppression efficiency compared to double-layer designs.\u003c/p\u003e"},{"header":"1. Introduction","content":"\u003cp\u003eThe global shift toward electric vehicles (EVs) under the \"dual carbon\" initiative has escalated the demand for lithium-ion batteries (LIBs), with projected installed capacity exceeding 500 GW by 2033\u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e. However, the manufacturing process of lithium-ion batteries is complex. To facilitate the full reaction between active materials and electrolyte\u003csup\u003e[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/sup\u003e, the cells are subjected to a period of resting after electrolyte injection and formation\u003csup\u003e[\u003cspan additionalcitationids=\"CR6\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e. Despite their widespread adoption, LIBs pose significant safety risks during manufacturing and storage, particularly due to thermal runaway (TR) triggered by process deviations or mechanical impacts\u003csup\u003e[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/sup\u003e. While material enhancements\u003csup\u003e[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/sup\u003e and applying external thermal management systems\u003csup\u003e[\u003cspan additionalcitationids=\"CR13\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/sup\u003emitigate some risks, fire suppression remains a critical challenge.\u003c/p\u003e \u003cp\u003eStudies on lithium battery fire extinguishing have been carried out by many scholars at home and abroad\u003csup\u003e[\u003cspan additionalcitationids=\"CR16 CR17 CR18 CR19\" citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/sup\u003e. Sun et al.\u003csup\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/sup\u003einvestigated the suppression effects of HFC-227ea (heptafluoropropane fire extinguishing agent), C6F12O (perfluorohexanone) and water on TR of lithium-ion batteries. The results showed that water had the best cooling effect and could suppress the propagation of TR, and C6F12O could reduce the battery temperature but failed to suppress TR propagation, and HFC-227ea had the poorest effect. When water is atomized into water mist, its surface area increases under the same volume, thereby enhancing the heat exchange capacity\u003csup\u003e[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]\u003c/sup\u003e. Lou et al.\u003csup\u003e[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]\u003c/sup\u003e studied the influence of water mist on fires in energy storage power stations, and the results indicated that the suppression effect of the water mist fire extinguishing system was positively correlated with the spray flow rate, spray cone angle and nozzle flow velocity of the water mist. The fire-extinguishing efficiency of water mist can be further improved by adding physical or chemical reagents. Wang et al.\u003csup\u003e[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]\u003c/sup\u003e proposed a novel fire-extinguishing method using a new type of composite additive compatible with water mist, and found that both physical and chemical additives played a significant role in fire extinguishing, which was more effective than pure water mist. In addition, many scholars have dedicated themselves to researching new and highly efficient fire extinguishing agents\u003csup\u003e[\u003cspan additionalcitationids=\"CR26 CR27\" citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]\u003c/sup\u003e. Li et al.\u003csup\u003e[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]\u003c/sup\u003e proposed a dry powder fire extinguishing agent compounded with inorganic phase change materials, the results showed that the composite dry powder fire extinguishing agent can not only effectively extinguish fires but also suppress the propagation of TR. Zhou et al.\u003csup\u003e[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]\u003c/sup\u003e developed a gel-type foam fire extinguishing agent, and the results indicated that the fire extinguishing time of the gel-protein foam fire extinguishing agent was reduced by 71.43% compared with that without any fire extinguishing agent. Deng et al.\u003csup\u003e[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/sup\u003e studied the TR suppress ability and cooling effect of three different nanofluid sprays (boron nitride, aluminum oxide, and titanium dioxide) on lithium-ion batteries, the results showed that nanofluid sprays have a stronger cooling effect than water mist.\u003c/p\u003e \u003cp\u003eCurrently, many research focus in the field of lithium-ion battery TR has mostly centered on fire extinguishing agent types and additive modification, with insufficient attention paid to the practical application scenarios. In particular, this study systematically investigates the TR propagation characteristics of lithium batteries in warehouse environments and the efficacy of automatic sprinkler systems, aiming to provide a reference for optimizing the prevention and control system of lithium battery fires in complex warehouse scenarios.\u003c/p\u003e"},{"header":"2. Material and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Experimental System\u003c/h2\u003e \u003cp\u003eA full-scale fire-extinguishing platform was constructed, with featuring flame-retardant battery shelves, heating devices, thermocouples, and real-time monitoring systems, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Experimental Materials and Equipment\u003c/h2\u003e \u003cp\u003eThe 46120 cylindrical ternary lithium battery was selected as the research object, with a single cell dimension of 46mm in diameter and 120mm in height. The state of charge (SOC) of the cells was 53%, consistent with the actual SOC of cells in factory storage. The shelves were constructed according to the static storage shelves currently used in lithium battery factories, with a layer height of 750mm and a single shelf height of 375mm. To facilitate easier activation of the sprinkler system, the response temperature of the sprinklers was set to 68℃, and a sufficiently large flow rate was selected to ensure rapid cooling of the cell surfaces and suppression of open flames. Therefore, K161 and K80 sprinkler were used in the system. The experimental materials used are listed in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eThe equipment used in the experiment include cameras, DC regulated power supplies, data acquisition systems, and thermocouples, among others. With reference to GB38031-2025 \u003cem\u003eSafety Requirements for Traction Batteries of Electric Vehicles\u003c/em\u003e, the power of the heating sheet used in the experiment was set to 300W\u003csup\u003e[\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]\u003c/sup\u003e.Other materials such as Teflon tape, insulating tape, and connecting wires are all standard products.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Experimental Methods\u003c/h2\u003e \u003cdiv id=\"Sec6\" class=\"Section3\"\u003e \u003ch2\u003e2.3.1 Experimental Scheme\u003c/h2\u003e \u003cp\u003ePrior to the experiment, the state of charge (SOC) of the cells was ensured to be 53%. The horizontal spacing between cells was 8mm, and the vertical spacing was 12mm. Through investigating different heating positions (upper tray edge, lower tray edge, lower tray center), different sprinkler arrangement (top-spray, side-spray), and different shelf configuration layouts s (double-layer, single-layer), this study systematically explored the TR propagation rate, as well as the response and fire-extinguishing effect of the sprinkler system. The specific experimental schemes are as follows:\u003c/p\u003e \u003cp\u003eTo study the TR propagation behavior of under different heating cell positions, temperature measurement points are arranged in Cases A, B, and C. Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e shows the thermocouple layouts under different cases.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section3\"\u003e \u003ch2\u003e2.3.2 Calculation of TR Propagation Rate\u003c/h2\u003e \u003cp\u003eThe TR propagation rate is one of the key parameters for evaluating the risk level of battery pack\u003csup\u003e[\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]\u003c/sup\u003e, which can be calculated based on the time interval and spatial distance between TR events of adjacent cells\u003csup\u003e[\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]\u003c/sup\u003e.\u003cdiv id=\"Equ1\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ1\" name=\"EquationSource\"\u003e\n$$\\text{V}\\text{=}\\frac{\\text{L}}{\\text{∆}\\text{t}}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e1\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eWhere, \u003cem\u003eL\u003c/em\u003e is the distance between two adjacent cells, in m; \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\text{∆}\\text{t}\\text{}\\)\u003c/span\u003e\u003c/span\u003eis the time interval from thermal runaway of the previous cell to TR of the next cell, in s; \u003cem\u003eV\u003c/em\u003e is in m/s. The horizontal and vertical propagation processes of TR are shown in the following figure:\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe horizontal spacing between two adjacent cells in shelf storage is 8\u0026times;10⁻\u0026sup3;m, and the vertical spacing is 1.2\u0026times;10⁻\u0026sup3;m. The horizontal and vertical propagation speeds of TR directly reflect the diffusion rate of TR in different directions of the battery pack.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section3\"\u003e \u003ch2\u003e2.3.3 Calculation Method for Sprinkler System Efficacy\u003c/h2\u003e \u003cp\u003e(1) Response matching degree\u003c/p\u003e \u003cp\u003eThe sprinkler response matching degree is an indicator to evaluate the adaptability between the response capability of the automatic fire extinguishing system and the fire scenario. Assume that the time from TR of the first cell in the battery pack to the start of sprinkler is \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\text{∆}{\\text{t}}_{\\text{1}}\\)\u003c/span\u003e\u003c/span\u003e, the number of cells with TR propagation is n, and the time from TR of the nth cell to triggering the sprinklers is the fastest response time that the sprinklers can achieve, denoted as \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\text{∆}{\\text{t}}_{\\text{o}}\\)\u003c/span\u003e\u003c/span\u003e. The response matching degree can be expressed as:\u003cdiv id=\"Equ2\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ2\" name=\"EquationSource\"\u003e\n$$\\text{R}\\text{=}\\frac{\\text{∆}{\\text{t}}_{\\text{o}}}{\\text{∆}{\\text{t}}_{\\text{1}}}\\text{\u0026middot;100%}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e2\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eThe response matching degree can quantify the gap between the actual response speed and the theoretical optimal speed. When \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\text{∆}{\\text{t}}_{\\text{1}}\\)\u003c/span\u003e\u003c/span\u003e is close to \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\text{∆}{\\text{t}}_{\\text{o}}\\)\u003c/span\u003e\u003c/span\u003e, the ratio is large, indicating timely response, which can effectively suppress TR propagation; conversely, if \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\text{∆}{\\text{t}}_{\\text{1}}\\)\u003c/span\u003e\u003c/span\u003e is much larger than \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\text{∆}{\\text{t}}_{\\text{o}}\\)\u003c/span\u003e\u003c/span\u003e, the ratio approaches 0, indicating delayed response and large-scale spread of TR.\u003c/p\u003e \u003cp\u003e(2) Fire-extinguishing water consumption\u003c/p\u003e \u003cp\u003eWater consumption is one of the important parameters for evaluating the fire-extinguishing effect of sprinkler systems\u003csup\u003e[\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]\u003c/sup\u003e. It is calculated as the product of its operating time and the flow rate\u003csup\u003e[\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]\u003c/sup\u003e.\u003cdiv id=\"Equ3\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ3\" name=\"EquationSource\"\u003e\n$${\\text{Q}}_{\\text{w}}\\text{=}\\text{Q}\\text{\u0026middot;}\\text{∆}{\\text{t}}_{\\text{s}}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e3\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eWhere, \u003cem\u003eQ\u003c/em\u003e is the sprinkler flow rate, in L/min; \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\text{∆}{\\text{t}}_{\\text{s}}\\)\u003c/span\u003e\u003c/span\u003e is the time from sprinkler activation to complete extinction of open flames in the shelf. In top-spray Case(Case A,B,C,G,H), the number of sprinkler is one with a flow rate of 322 L/min. In side-spray Case(Case D,F), the number of sprinkler is four, with a total flow rate of 640 L/min.\u003c/p\u003e \u003cp\u003e(3) Benchmark water consumption\u003c/p\u003e \u003cp\u003eAssume that the sprinklers are turned on immediately after TR of the first cell, and the sprinklers directly act on the TR cell. The minimum water consumption required from sprinkler activation to complete extinction of flames is the benchmark water consumption, denoted as\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({\\text{Q}}_{\\text{0}}\\)\u003c/span\u003e\u003c/span\u003e. Benchmark water consumption is the core benchmark parameter of the resource utilization efficiency indicator in the evaluation of f efficiency of sprinkler system. It is measured through experiments that\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({\\text{}\\text{Q}}_{\\text{0}}\\)\u003c/span\u003e\u003c/span\u003e is approximately 80L.\u003c/p\u003e\u003cp\u003e(4) Resource utilization efficiency\u003c/p\u003e\u003cp\u003eResource utilization efficiency is an indicator to measure the effective utilization degree of water resources in the fire-extinguishing process, reflecting the rationality of system design, scientificity of operation, and water-saving level. Its core is the ratio of theoretical water consumption to actual water consumption, i.e.:\u003cdiv id=\"Equ4\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ4\" name=\"EquationSource\"\u003e\n$$\\eta\\text{=}\\frac{{\\text{Q}}_{\\text{0}}}{{\\text{Q}}_{\\text{w}}}\\text{\u0026middot;100%}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e4\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eIn the actual fire-extinguishing process, the closer \u003cspan class=\"InlineEquation\"\u003e\u003c/span\u003eis to \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({\\text{Q}}_{\\text{0}}\\)\u003c/span\u003e\u003c/span\u003e, the closer the system is to the ideal state in water consumption control, with less resource waste; conversely, the larger the difference between \u003cspan class=\"InlineEquation\"\u003e\u003c/span\u003eand \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({\\text{Q}}_{\\text{0}}\\)\u003c/span\u003e\u003c/span\u003e, the farther the actual water consumption deviates from the theoretical optimal value, and the lower the resource utilization efficiency. A higher utilization efficiency indicates less water waste and better efficiency of sprinkler system.\u003c/p\u003e \u003cp\u003e(5) Efficiency of water sprinkler system\u003c/p\u003e\u003cp\u003eEfficiency is the core indicator to measure whether the sprinkler system is efficient. The efficiency of the sprinkler system is comprehensively evaluated by the response matching degree and resource utilization efficiency. Denote the efficiency of the sprinkler system as \u003cem\u003eE\u003c/em\u003e, then \u003cem\u003eE\u003c/em\u003e can be expressed as:\u003cdiv id=\"Equ5\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ5\" name=\"EquationSource\"\u003e\n$$\\text{E}\\text{=}\\text{R}\\text{\u0026middot;}\\eta\\text{\u0026middot;100%}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e5\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"3. Results","content":"\u003cp\u003e \u003cb\u003e3.1 Analysis of TR Risk and Efficiency of Water Sprinkler System at Different Positions in the Shelf\u003c/b\u003e \u003c/p\u003e \u003cdiv id=\"Sec10\" class=\"Section3\"\u003e \u003cdiv class=\"Heading\"\u003e3.1.1 TR Propagation under Different Heating Positions\u003c/div\u003e \u003cp\u003eFrom Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(a), under Condition A, the safety valve of the heated cell opened at 344 seconds, and the temperature rise rate exceeded 1℃/s at approximately 351 seconds, indicating that the cell underwent TR. From Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(b), it is observed that the surface temperatures of all cells except the heated one were below 40℃. Although the surface temperature rise rate of some cells exceeded 1℃/s, this was caused by the flames generated from the combustion and explosion of the heated cell after TR coming into contact with their surfaces. Post-experiment observations confirmed that only the heated cell experienced TR. The sprinkler system did not activate under Condition A, and the same result was observed in three repeated experiments.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFrom Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e(a) and (b), two cells underwent TR under Condition B. At 287 seconds after the TR of the heated cell, its left-side cell occured TR. The sprinkler system was activated 3 seconds later, and the flame was completely extinguished after 18s of sprinkler action. It can be observed from Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e(c) that the temperatures of the remaining cells did not exceed 30℃, with no risk of TR. Lateral propagation of TR occurred under Condition B.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFrom Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e(a) and (b), three cells underwent TR under Condition C. At 145 seconds after the TR of the heated cell, its adjacent cell experienced TR. After another 11 seconds, the cell directly below the heated cell occured TR. The sprinkler system was activated 1 seconds later, and the flame was completely extinguished after 45 seconds of sprinkler action. Under Condition C, TR propagated in both horizontal and vertical directions.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. lists the horizontal and vertical propagation times of battery TR under different cases. It is worth noting that in Case C, although TR spreads to the lower layer cell 11 seconds after TR of the second cell, but vertical propagation is affected by the synergistic heating of the first and second TR cells. Therefore, when calculating the TR propagation speed, the propagation time is the time from TR of the first cell to the third cell.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eNumber of TR cells and horizontal\u0026amp;vertical propagation times under different heating positions\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTest Case\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNumber of TR cells\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eHorizontal propagation time of TR (s)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eVertical propagation time of TR (s)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e287\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e145\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e157\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e. shows the horizontal and vertical propagation speeds of TR cell under different cases. It can be seen from Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e. that in Case B, TR of cells propagates horizontally with a propagation speed of 2.8\u0026times;10⁻⁵m/s; in Case C, cells propagate in both horizontal and vertical directions, with a horizontal TR propagation speed of 5.5\u0026times;10⁻⁵m/s and a vertical propagation speed of 7.7\u0026times;10⁻⁵m/s. The vertical propagation speed of cells is faster, 28.6% faster than the horizontal one.This is because the cell's safety valve is located at the bottom, after the valve opens, pressure is released downward, and the energy release direction is mainly downward, leading to faster propagation of TR.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section3\"\u003e \u003cdiv class=\"Heading\"\u003e3.1.2 Efficiency of Sprinkler System under Different TR Positions\u003c/div\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e. calculates various performance parameters of the fire-extinguishing system after TR of cells at different positions. As shown in Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e., Condition B consumes less water, which is because fewer cells occur TR, simplifying suppression efforts. In contrast, the sprinkler system in Condition C responds faster, which is determined by the movement regularity of flue gas\u003csup\u003e[\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]\u003c/sup\u003e: after TR occurs in the lower tray cells, the flue gas moves vertically upward under the drive of thermal buoyancy. However, in Condition A, after TR occurs in the edge cells, the flames and flue gas mainly gather at the lower edge due to the blocking of the upper tray, and the upper sprinklers do not reach the activation temperature. Therefore, for top-spray systems, the sprinkler activation is slower when TR occurs in edge cells.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePerformance parameters of sprinkler system after TR of cells at different positions\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTest Case\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSprinkler flow rate\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\text{∆}{\\text{t}}_{\\text{1}}\\)\u003c/span\u003e\u003c/span\u003e(s)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\text{∆}{\\text{t}}_{\\text{o}}\\)\u003c/span\u003e\u003c/span\u003e(s)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eWater consumption (L)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eR\u0026nbsp;(%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eη\u0026nbsp;(%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cem\u003eE\u003c/em\u003e\u0026nbsp;(%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e322L/min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e322L/min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e290\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e96.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e82.81\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.86\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e322L/min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e157\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e241.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e33.13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.21\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e. shows the response matching degree, resource utilization efficiency, and efficiency of the sprinkler system under different cases. It can be seen from Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e. that the response matching degrees of the sprinkler system under different cases are 0%, 1.04%, and 0.64% respectively; the resource utilization efficiency are 0%, 82.81%, and 33.13% respectively; the efficiencies are 0%, 0.86%, and 0.21% respectively. The efficiency of the sprinkler system in Case B is higher, which is approximately 75.6% higher than that in Case C. Therefore, under the top-spray scheme, when TR occurs in the center cell of the lower tray, the sprinkler system can exert greater efficiency, with highest resource utilization efficiency.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Efficiency of Sprinkler System under Different Sprinkler Arrangements\u003c/h2\u003e \u003cp\u003eBased on the analysis in Section \u003cspan refid=\"Sec2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, it is found that for top-spray systems, the sprinkler system exhibits lower efficacy when TR occurs in inner edge cells. Therefore, the top-spray system was replaced with a side-spray system. Experimental results show that the sprinklers did not activate under Conditions D and F, even after three repeated experiments for each condition, the sprinklers still failed to activate. In addition to the influence of flue gas movement regularity, this phenomenon is also related to the cell structure. During TR of cells, their internal temperature rises sharply, and high-temperature ejecta are ejected from the pressure relief valve. The sprinkler heads of top-spray systems, which are directly facing the top space of the shelves, can respond more quickly to high-temperature signals at the top. In contrast, side-spray systems may be blocked by shelf laminates or battery trays, failing to sense the high temperature at the top in a timely manner and unable to effectively capture hot flue gas, resulting in activation delay.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Efficiency of Sprinkler System under Different Shelf Layouts\u003c/h2\u003e \u003cp\u003eFrom the comparison between the top-spray and side-spray schemes in the previous section, it is found that the top-spray is more likely to activate the sprinkler. Based on this, the shelf layout were optimized: the double-layer shelf was changed to a single-layer one, and two working conditions were set, i.e., TR of cells at the inner edge and those at the centre position.\u003c/p\u003e \u003cp\u003eIt can be seen from the experimental videos that there was no propagation of TR in Conditions G and H, and the sprinkler system could be activated immediately after the TR of the first cell. In Condition G, the sprinkler system was activated 16 seconds after the cell's TR, and the flame was extinguished 32 seconds after the sprinkler was activated. In Condition H, the sprinkler system was activated 7 seconds after the cell's TR, and the flame was extinguished 83 seconds. Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e. calculates various performance parameters of the sprinkler system under different shelf layouts.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab6\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePerformance parameters of sprinkler system under different shelf layouts\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTest Case\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSprinkler flow rate\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\text{∆}{\\text{t}}_{\\text{1}}\\)\u003c/span\u003e\u003c/span\u003e(s)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\text{∆}{\\text{t}}_{\\text{o}}\\)\u003c/span\u003e\u003c/span\u003e(s)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eWater consumption (L)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eR\u0026nbsp;(%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eη\u0026nbsp;(%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cem\u003eE\u003c/em\u003e\u0026nbsp;(%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e322L/min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e290\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e96.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e82.81\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e0.86\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e322L/min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e157\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e241.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e33.13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e0.21\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e322L/min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e170.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e46.87\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e46.87\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eH\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e322L/min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e442.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e18.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e18.07\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eFrom Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e., in Condition B, the \u003cem\u003eE\u003c/em\u003e value is 0.86%, which is at a moderately low level among all conditions, however, the lower water consumption alleviates the insufficient efficacy to a certain extent. In Condition C, the actual response of the sprinkler is also delayed, and the propagation range of TR may expand due to the delay, with the corresponding \u003cem\u003eE\u003c/em\u003e value being only 0.21%, the lowest among all conditions. Condition G shows the most prominent performance: the sprinkler responds quickly, can intervene rapidly in the early stage of TR, and has high resource utilization efficiency, with an \u003cem\u003eE\u003c/em\u003e value as high as 46.87%, indicating the optimal comprehensive efficacy. The response time of Condition H is significantly shorter than that of Conditions B, C, and G, but its water consumption is relatively high. This is because the sprinkler heads are close to the trays, resulting in a spraying blind area directly below them, and the corresponding E value is 18.07%.\u003c/p\u003e \u003cp\u003eOverall, the optimized shelf layout and sprinkler system have better efficiency. After TR of the inner edge cell, compared with Cases C and G, the response time of the optimized sprinkler system is shortened by 89.8%, and the efficiency of the sprinkler system is improved by 99.6%; after TR of the center cell, compared with Cases B and H, the response time of the optimized sprinkler system is shortened by 97.6%, and the efficiency of the sprinkler system is improved by 95.2%.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4. Conclusions","content":"\u003cp\u003e(1) TR propagation in the shelf is strongly correlated with the location of the TR cell, and TR propagation is directionally asymmetric, with vertical speeds 28.6% faster than horizontal speeds. TR of the center cell of the lower tray only propagates horizontally (speed 2.8\u0026times;10⁻⁵m/s), while TR of the edge cell is limited by the structure with no obvious spread. This difference stems from the synergistic effect of cell arrangement density, pressure relief direction, and heat accumulation path.\u003c/p\u003e \u003cp\u003e(2) Top-spray systems are optimal for warehouse applications, aligning with flue gas dynamics. The top-spray sprinkler arrangement has exhibits superior suppression efficiency with a 1-second response time, outperforming side-spray sprinkler, which failed to trigger sprinkler response. Its advantage lies in matching the vertical upward characteristics of flue gas, which can quickly trigger the sprinkler through high-temperature flue gas. The side-spray system is not suitable for densely stored shelves because it is shielded by shelves and cannot effectively capture hot flue gas.\u003c/p\u003e \u003cp\u003e(3) The optimized shelf layout significantly improves the efficiency of sprinkler system. After changing the double-layer shelf to a single-layer one, the sprinkler activation time is shortened from 290 seconds to 7\u0026ndash;16 seconds (optimized Conditions H and G), and the efficacy (\u003cem\u003eE\u003c/em\u003e value) is increased to 18.07%-46.87%. In cases where TR occurs in the inner edge cells and middle cells, the response time of the optimized sprinkler system is shortened by 89.8% and 97.6% respectively, and the efficacy is improved by 99.6% and 95.2% respectively.\u003c/p\u003e \u003cp\u003e(4) The efficacy of the sprinkler system can be evaluated through the dual dimensions of \"response matching degree - resource utilization efficiency\". The proposed evaluation model (response matching degree \u0026times; resource efficiency) effectively quantifies system performance. In the optimized Condition G, ∆\u003cem\u003et\u003c/em\u003e₁ (16 seconds) perfectly matches ∆\u003cem\u003et\u003c/em\u003e₀ (16 seconds) with reasonable water consumption control, thus achieving the optimal efficacy. In contrast, in the unoptimized Condition C, since ∆\u003cem\u003et\u003c/em\u003e₁ (157 seconds) is much longer than ∆\u003cem\u003et\u003c/em\u003e₀ (1 seconds) and the water consumption is as high as 241.5L, the efficacy is only 0.21%.\u003c/p\u003e \u003cp\u003eThis work advances LIB storage safety by integrating empirical TR data with fire suppression optimization, offering a framework for future industrial standards.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003e\"[X.L.] and [Y.S.] conceived and designed the analysis. [W.Z.] collected the data. [M.Y.] and [X.Y.] performed the analysis. [Z.Z.] and [Y.S.] contributed to the interpretation of the results. [X.L.] wrote the first draft of the manuscript. All authors reviewed, edited, and approved the final version of the manuscript.\"\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eMAMMACıOĞLU O (2025) A new experimental approach to lithium-ion battery fires in electric vehicles: Investigation of fire behavior and effectiveness of extinguishing agents [J]. Case Stud Therm Eng 73:106554. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e.doi.org/https://doi.org/10.1016/j.csite.2025.106554\u003c/span\u003e\u003cspan address=\".10.1016/j.csite.2025.106554\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDIOHA M O, LUKUYU J, VIRG\u0026uuml;EZ E et al (2022) Guiding the deployment of electric vehicles in the developing world [J]. 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J Hazard Mater 379:120730. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003edoi.org/https://doi.org/10.1016/j.jhazmat.2019.06.007\u003c/span\u003e\u003cspan address=\"10.1016/j.jhazmat.2019.06.007\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTables 1 to 3 are available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"fire-technology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"fire","sideBox":"Learn more about [Fire Technology](http://link.springer.com/journal/10694)","snPcode":"10694","submissionUrl":"https://submission.springernature.com/new-submission/10694/3","title":"Fire Technology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"lithium-ion batteries, Shelf storage, Thermal runaway propagation, Efficacy of sprinkler system","lastPublishedDoi":"10.21203/rs.3.rs-8995646/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8995646/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eTaking the 46120 cylindrical ternary lithium-ion battery as the research object, A full-scale experimental setup with 512 cells was designed to evaluate TR behavior under varying conditions, including TR initiation positions (upper tray edge, lower tray edge, lower tray center), sprinkler arrangements (top-spray, side-spray), and shelf layouts (double-layer, single-layer). The experimental results show that the TR propagation is highly dependent on cell location, and under the same case, the vertical propagation speed (7.7\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003em/s) is significantly higher than the horizontal(5.5\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003em/s). In different sprinkler layout configuration, the top-spray sprinkler arrangement has suppression efficiency with 1-seconds response time, outperforming side-spray sprinkler, which failed to trigger sprinkler response. After the optimization of the shelf layout, the sprinkler trigger time is shortened by 89.8% and 97.6% for edge and center TR positions, respectively, while the efficiency of the sprinkler system is improved by 99.6% and 95.2%. This study provides critical data for optimizing fire protection systems in lithium-ion battery storage facilities, and has reference significance for the storage safety of lithium-ion batteries.\u003c/p\u003e","manuscriptTitle":"Analysis on Thermal Runaway Propagation Characteristics and Efficacy of Water Sprinkler System in Shelf Storage of 46120 Ternary Lithium Batteries","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-10 17:13:43","doi":"10.21203/rs.3.rs-8995646/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-04-02T16:34:42+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-02T09:09:38+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-03-20T18:44:42+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"168889286055516815755877352454589749401","date":"2026-03-10T09:35:53+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"70722589113295005305987676469642297391","date":"2026-03-06T16:26:35+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-03-05T10:23:50+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-03-05T08:00:15+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-03-04T09:39:36+00:00","index":"","fulltext":""},{"type":"submitted","content":"Fire Technology","date":"2026-02-28T13:13:08+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"fire-technology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"fire","sideBox":"Learn more about [Fire Technology](http://link.springer.com/journal/10694)","snPcode":"10694","submissionUrl":"https://submission.springernature.com/new-submission/10694/3","title":"Fire Technology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"0164e62c-86d6-450d-89f7-530f02c1cd0e","owner":[],"postedDate":"March 10th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"in-revision","subjectAreas":[],"tags":[],"updatedAt":"2026-04-02T16:39:26+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-10 17:13:43","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8995646","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8995646","identity":"rs-8995646","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}