Articles
Thermal Runaway Characteristics of 18650 NCM Lithium-ion Batteries under the Different Initial Pressures
2022 Volume 90 Issue 8 Pages 087004
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2022 Volume 90 Issue 8 Pages 087004
To better understand the thermal runaway characteristics of lithium-ion batteries in civil aviation transportation environments, an experimental platform for the fire and explosion of lithium-ion batteries was designed and built. The 18650 NCM lithium-ion battery was selected as the test sample to study the influence of different initial pressures on the thermal runaway characteristics of the lithium-ion battery pack in a confined space. The results showed that, under 61 kPa, the initial thermal runaway triggering time is longer, the initial thermal runaway temperature is higher, and the explosion pressure and TNT equivalent are lower than that under 96 kPa. The mass loss increased with the increase of pressure and the number of batteries. In addition, the initial thermal runaway triggering time and temperature are affected by the number of batteries. These results could provide some support for civil aviation transportation safety.
The lithium-ion battery has been widely used nowadays because of its high power density, rapid charging rate, and long life circle. However, in the process of civil aviation transportation and the lithium-ion battery equipment carried by passengers, once the lithium-ion battery explodes, there will be an immeasurable loss to the aircraft and passenger life. According to the statistics from Federal Aviation Administration in 2022,1 about 365 accidents involving lithium-ion batteries had happened on aviation cargo and passenger baggage since 2006, most of which result from the abrupt thermal runaway of lithium-ion batteries causing fire or explosion. With the increasing lithium-ion battery accidents, enough preparation urgently in civil aviation transportation should be well arranged, thus understanding the thermal runaway characteristics of lithium-ion batteries is impending.
There are many forms of lithium-ion batteries fire, such as steady combustion, jet explosions, and deflagrations and explosions. The different explosions of batteries result from the heat and pressure accumulation by internal component reactions under abuse conditions, such as overheating, overcharging, and short-circuiting.2–4 Scholars from home and abroad have done much research on the thermal runaway characteristics of lithium-ion batteries. Wang explores the thermal performance of battery modules under different cell arrangement structures and air-cooling strategies are also investigated by installing the fans in the different locations of the battery module to improve the temperature uniformity. The results showed that the most desired structure with forced air cooling is a cubic arrangement, while the hexagonal structure is optimal when focusing on the space utilization of the battery module.5 Chen investigated the temperature rises of LiBs caused by external short circuits. The impacts of the battery state of charge (SOC) and ambient temperature condition on the maximum temperature rise are disclosed.6 Larsson carried out the abuse tests including overcharge, short circuit, the propane fire test, and external heating test (oven). It was found that in a fire, cells with higher SOC gave a higher heat release rate (HRR), while the total heat release (THR) had a lower correlation with SOC.7 Lopez adopted nine 18650 lithium-ion batteries to study the effect of cell interconnecting tab style, cell spacing, and protection materials. They found that both the 2 mm spacing and the thermal insulation materials between the cells could alleviate the spread of thermal runaways significantly.8 We studied effectiveness of aerogel felt thickness on thermal runaway propagation of lithium ion batteries. The results showed that different arrangement and the distance between batteries would directly affect the combustion severity of lithium ion batteries.9
Nevertheless, with the wide use of lithium-ion batteries in various industries, the aviation transportation volume of lithium-ion batteries begins to increase, to avoid terrible accidents, it is important to study the thermal runaway characteristics of lithium-ion batteries. Especially in various atmospheric pressure civil aviation flight conditions. Environmental pressure has a significant influence on the thermal runaway of lithium-ion batteries.10–12 An experimental study is taken on the ignition and combustion characteristics of lithium ion batteries under a low-pressure tank to investigate the effectiveness of low-pressure on the fire suppression of lithium ion batteries in an aircraft environment. It is found that the average mass loss rate and surface and the peak flame temperatures decrease whereas the time to deflation, ignition and thermal runaway increase with the reduction of the pressure, demonstrating a lower fire risk.13 Chen conducted experiments on the fire risk of lithium-ion batteries in Hefei (100.8 kPa, 24 m) and Lhasa (64.3 kPa, 3650 m). At higher altitudes, the mass loss, heat release rate, and total heat release both for a single battery and bundle batteries decreased.14 Sun carried out serial experiments in the dynamic pressure and temperature-varying experimental cabin, which can simulate the flight-changing conditions. The results showed that the decrease of environmental pressure could not block the thermal runaway propagation between the cylindrical lithium batteries, but the high-temperature zones generated by the thermal runaway hazard release of lithium batteries decreased.15 However, the current studies on thermal runaway characteristics of lithium-ion batteries under different conditions mainly focus on the changes of external conditions such as arrangement mode, charged state, and pressure, and few studies consider several variables together. In the process of air transport, lithium-ion batteries are placed in relatively confined spaces during transportation and electronic devices carried by passengers, and aircraft cabin and cargo space are in a low-pressure environment, the change of the environment will inevitably affect the combustion reaction process, which is different from the atmospheric pressure environment.
Therefore, in this paper, an experiment was conducted in a self-designed confined space under different pressure. Four cases of one to four batteries with 100 % SOC were configured at two initial pressure conditions, 96 kPa (Guanghan) and 61 kPa (Kangding). The influence of pressure on the thermal runaway characteristics of parallel lithium-ion batteries was studied by simulating the conditions of lithium-ion batteries in civil aviation transportation. The typical parameters such as the real-time temperature, the explosion pressure, and mass loss et al., were measured to investigate the initial pressure effect on explosion characteristics. These results could provide some support for civil aviation transportation safety.
The lithium-ion battery is one of the major energy devices which had a high power density and a long life cycle. The batteries which were used in the experiment were LR1865SZ produced by Lishen Battery Company, and there were with 100 % SOC and 2600 mAh capacity. The cathode and anode materials are nickel manganese cobalt (NMC) and graphite, respectively. The reaction mechanism of the charging and discharging process is shown as follows.16
Positive electrode:
| \begin{equation} \text{Li(Ni$_{a}$Co$_{b}$Mn$_{c}$)O$_{2}$} \rightleftarrows \text{Li$_{1 - x}$(Ni$_{a}$Co$_{b}$Mn$_{c}$)O$_{2}$} + \text{$x$Li$^{+}$} + \text{$x$e$^{-}$} \end{equation} | (1a) |
| \begin{equation} \text{6C} + \text{$x$Li$^{+}$} + \text{$x$e$^{-}$} \rightleftarrows \text{Li$_{x}$C$_{6}$} \end{equation} | (1b) |
| \begin{equation} \text{Li(Ni$_{a}$Co$_{b}$Mn$_{c}$)O$_{2}$} + \text{6C} \rightleftarrows \text{Li$_{x}$C$_{6}$} + \text{Li$_{1 - x}$(Ni$_{a}$Co$_{b}$Mn$_{c}$)O$_{2}$} \end{equation} | (1c) |
The experimental platform for lithium-ion battery fire and explosion was designed and built on a basis of the explosion-proof tank with a battery fixing bracket, as shown in Fig. 1. The effective internal volume was 60 L. The main experimental configurations were summarized in Table 1. The detailed arrangement of lithium-ion batteries and the side view of the arrangement in lithium-ion batteries are shown in Figs. 2 and 3, respectively. An electric heating rod with a length of 100 mm and a power of 200 W was selected to simulate the external heat source and triggered thermal runaway by heating, and when the lithium-ion battery in contact with the heating rod has thermal runaway, the heating stops. The temperature was measured by K-type thermocouples (WRNK-191, produced in Shanghai Kejie Instrument Factory) with the range 0–1000 °C. A piezoresistive pressure sensor (CYG1146, produced in Baoji Qinming Sensor Co., LTD) was used to measure the explosion pressure of the lithium-ion battery, which was placed 20 cm vertically from the positive terminal of the battery. The detection range was 0–5 MPa. NI-cDAQ-9135 data acquisition system was used to record the real-time temperature and explosion pressure with the frequency of 100 Hz. The electronic scale was applied to record the mass loss of the battery. The experiment was carried out under a sealed condition. In order to ensure the repeatability of the experiment, each experiment was repeated 3 times.
An experimental platform for lithium-ion battery test: the experiment was carried out under a sealed condition. The use of an electric heating rod is the trigger for lithium-ion battery thermal runaway, and when the lithium-ion battery in contact with the heating rod has thermal runaway, the heating stops. The temperature was measured by thermocouples. A piezoresistive pressure sensor was used to measure the explosion pressure of the lithium-ion battery, which was placed 20 cm vertically from the positive terminal of the battery. NI-cDAQ-9135 data acquisition system was used to record the real-time temperature and explosion pressure. The electronic scale was applied to record the mass loss of the battery.
| Experiment setting |
Number of battery |
SOC /% |
Power /W |
Measurement Parameter |
Number of thermocouples |
|---|---|---|---|---|---|
| Case A | 1 | 100 % | 200 W | Real-time temperature, Explosion pressure, Mass loss |
1 |
| Case B | 2 | 100 % | 200 W | 2 | |
| Case C | 3 | 100 % | 200 W | 3 | |
| Case D | 4 | 100 % | 200 W | 4 |
The detailed arrangement of lithium-ion batteries: I, II, III, and IV is the serial number of batteries. Case A to Case D is a linear array of different numbers of lithium-ion batteries. The use of an electric heating rod is the trigger for lithium-ion battery thermal runaway, and when the lithium-ion battery in contact with the heating rod has thermal runaway, the heating stops. The temperature was measured by thermocouples.
The side view of the arrangement in lithium-ion batteries: Case A to Case D is a linear array of different numbers of lithium-ion batteries.
Thermal runaway refers to the overheating phenomenon that the exothermic chain reaction inside the battery that causes the rapid change of the battery temperature rise rate. Therefore, Eq. 2 is introduced to better describe the temperature variation of the battery.
| \begin{align} t_{\text{onset,${i}$}} = \min\left\{k:\frac{T_{i}(k + 1) - T_{i}(k)}{t_{i}(k + 1) - t_{i}(k)} > 30\,{{}^{\circ}\text{C}}\,\text{s$^{-1}$}\right\},&\notag\\ (i = \text{I},\text{II},\text{III},\text{IV})& \end{align} | (2) |
The real-time temperature variation of lithium-ion batteries in four cases under two different initial pressure is shown in Fig. 3. The temperature variation of Case A is shown in Fig. 4a. It could be seen that the curvilinear trend is similar. Under 61 kPa, the initial thermal runaway time is 30 s longer and the response temperature is 75 °C lower than that under 96 kPa which is changed from 121 s to 91 s and 169 °C to 94 °C, respectively. The maximum temperature of batteries in each case is summarized in Table 2. Compared with 96 kPa, the maximum thermal runaway temperature is 10 °C lower under 61 kPa from 820 °C to 830 °C. The thermal runaway causes violent ejection along with much gas release. After the finish of the thermal runaway, the temperature curve turns down gradually until the room temperature. The temperature variation of Case B is shown in Fig. 4b. Both of the initial thermal runaway triggering time intervals of battery I and II under two pressure conditions are 60 s. The initial thermal runaway temperature of batteries I and II under 61 kPa are 55–68 °C higher than that under 96 kPa. The maximum thermal runaway temperature under 61 kPa are 46 °C and 6 °C lower than that under 96 kPa, respectively. The temperature variation of Case C is shown in Fig. 4c. The initial thermal runaway triggering time interval of battery I and II, battery II, and III are 103 s and 77 s under 61 kPa, 60 s, and 90 s under 96 kPa. Under 61 kPa, the initial thermal runaway triggering time is 90–133 s longer, the corresponding temperature is 22–63 °C higher and the maximum thermal runaway temperature is 27–44 °C lower than that under 96 kPa. The temperature variation of Case D is shown in Fig. 4d. The initial thermal runaway triggering time interval of battery I and II, battery II and III, battery III and IV are 117 s, 112 s, and 50 s under 96 kPa, 71 s, 125 s, and 63 s under 96 kPa. The time interval of batteries III and IV is shorter than that of other batteries. Under 61 kPa, the initial thermal runaway triggering time is 32–78 s longer, the corresponding temperature is 21–95 °C higher and the maximum thermal runaway temperature is 28–85 °C lower than that under 96 kPa.
The temperature variation of four cases under 96 kPa and 61 kPa: the curve in black represents 96 kPa. The curve in red represents 61 kPa. I, II, III and IV is the serial number of batteries, and they are separated by different shapes. Figure 4a shows the temperature variation of a lithium-ion battery under different pressures. Figure 4b shows the temperature variation of two lithium-ion batteries under different pressures. Figure 4c shows the temperature variation of three lithium-ion batteries under different pressures. Figure 4d shows the temperature variation of four lithium-ion batteries under different pressures.
| Experiment setting |
Initial pressure |
Battery I | Battery II | Battery III | Battery IV | ||||
|---|---|---|---|---|---|---|---|---|---|
| T/°C | t/s | T/°C | t/s | T/°C | t/s | T/°C | t/s | ||
| Case A | 96 kPa | 830 | 125 | — | — | — | — | — | — |
| 61 kPa | 820 | 134 | — | — | — | — | — | — | |
| Case B | 96 kPa | 756 | 135 | 753 | 213 | — | — | — | — |
| 61 kPa | 710 | 180 | 747 | 245 | — | — | — | — | |
| Case C | 96 kPa | 759 | 138 | 691 | 207 | 692 | 313 | — | — |
| 61 kPa | 715 | 234 | 730 | 323 | 719 | 420 | — | — | |
| Case D | 96 kPa | 751 | 136 | 753 | 260 | 739 | 366 | 762 | 415 |
| 61 kPa | 760 | 215 | 668 | 290 | 691 | 405 | 734 | 470 | |
The thermal runaway response time of a lithium-ion battery is directly related to the rate of thermal decomposition and electrochemical reaction in lithium-ion batteries and the rate of generating and releasing combustible gas. Under 61 kPa, the thermal runaway triggering time of the monomer of the battery pack increases. Firstly, the thermal resistance of the surface and internal materials of the lithium-ion battery increases due to low pressure. Secondly, with the increase in the number of batteries, the thermal resistance increases between the first exploded one and the rest unexploded batteries, and the heat conduction rate between the battery decreases. Thirdly, the low-temperature characteristics of the low-pressure environment and the decrease of oxygen concentration make the thermal emissivity from the high-temperature combustible material ejected by the explosion to the battery decrease, resulting in the increase in the total time of the explosion.
The initial thermal runaway temperature of batteries under 96 kPa rises 61 °C from 128 °C to 189 °C and rises 56 °C from 177 °C to 233 °C under 61 kPa from case A to case D. The initial thermal runaway temperature of batteries in four cases are shown in Fig. 5. With the increase in battery number, the initial thermal runaway temperature of the batteries apart from the heated battery is higher which is influenced by the amount of absorbed heat and transmitted heat. For the same battery, if the number of battery groups is larger, the initial thermal runaway triggering time and temperature are higher. Then the reason is explained by thermology.
The initial thermal runaway temperature of batteries in four cases under 96 kPa and 61 kPa: I, II, III, and IV is the serial number of batteries, and they are separated by different shapes.
The differential equation of heat conduction is shown in Eq. 3.18
| \begin{equation} \text{d}\phi_{\lambda} + \text{d}\phi_{v} = \text{d}U \end{equation} | (3) |
dϕλ is the sum of the heat conducted to the battery from three axes per unit time. dϕv is the heat generation inside the battery per unit time. dU is the increase of internal energy of the battery per unit time.
| \begin{equation} \rho C_{\text{p}}\frac{\partial T_{i}}{\partial n} = \nabla (\lambda \nabla T_{i}) + Q - A(T_{i} - T_{0}) - A\varepsilon \sigma (T_{i}^{4} - T_{0}^{4}) \end{equation} | (4) |
The heat conservation equation of the battery is shown in Eq. 419 which is the expansion formula of Eq. 3. Where ρ is the density of the battery. Cp is the specific heat of the battery. Ti is the battery temperature. T0 is the environment temperature. λ is the heat conductivity coefficient, and the subscript i represent batteries. Q is the total heat generation of the reactions inside the battery. h is the heat transfer coefficient. ε is the radiation coefficient. σ (5.67 × 10−8 W m−2 K−4) is the radiation constant.
In the preparation process of thermal runaway, SEI film is broken due to the heating energy of the heat source, and the electrode material reacts with the electrolyte to generate joule heat and meanwhile conducts heat to other batteries. At the same time, with the increase in the number of batteries, the distance of heat conduction increases, part of the heat is lost through thermal convection, and the required heat for ignition and explosion decreases, leading to a decrease in the temperature rise rate of the battery and the initial thermal runaway temperature. In addition, the fluctuation of the maximum temperature of thermal runaway in the battery pack starts to increase as the number of batteries increases. This is because the heat released by the battery injection and the complexity of the battery itself increase the constraint and interaction between the batteries in the process of battery ignition and explosion, which makes the thermal runaway process of the battery more complicated. Simultaneously, the increase of battery thermal resistance leads to the decrease of heat transfer rate under the low-pressure environment, while low pressure and low temperature inhibit the chemical reaction of the battery, resulting in a higher thermal runaway response temperature of the battery pack under low pressure.
Therefore, under 61 kPa, the initial thermal runaway time is longer, the initial thermal runaway temperature is higher, and the maximum thermal runaway temperature is lower.
3.2 The explosion pressureThe explosion pressure variation of lithium-ion batteries is shown in Fig. 6. It can be seen that the explosion pressure decreases gradually with thermal runaway propagation. This is an attribute to the increase in the number of batteries that increases the temperature propagation distance in the process of thermal runaway, and the heat conduction rate decreases. Finally, the heat acquired by the unexploded battery decreases in unit time. In the meantime, the oxygen content in the pressure barrel is consumed and decreases, resulting in insufficient oxygen required for the thermal runaway of the unexploded battery. The severity of the reaction between the thermal decomposition electrode material of the electrolyte in the battery and the REDOX reaction is weakened, resulting in the decline of the explosion injection pressure.
The explosion pressure variation of four cases under 96 kPa and 61 kPa: the curve in black represents 96 kPa. The curve in red represents 61 kPa. Figure 6a shows the explosion pressure variation of a lithium-ion battery under different pressures. Figure 6b shows the explosion pressure variation of two lithium-ion batteries under different pressures. Figure 6c shows the explosion pressure variation of three lithium-ion batteries under different pressures. Figure 6d shows the explosion pressure variation of four lithium-ion batteries under different pressures.
The maximum explosion pressure of the batteries in four cases is shown in Fig. 7. Under 61 kPa, the maximum explosion pressure is smaller than that under 96 kPa. The maximum explosion pressure under 96 kPa and 61 kPa in all cases are 0.228 MPa and 0.169 MPa, respectively. The explosion pressure in all cases under 61 kPa is 0.01–0.059 MPa lower than that under 96 kPa. One of the reasons for that is when the initial pressure is 61 kPa, the insufficient combustion of the combustible gas emitted by the combustion battery and the electrolyte in the combustion makes the oxygen in the pressure barrel drop more, resulting in the increase of the explosion limit of the mixed gas composed of the air in the barrel and the combustible gas released by the unexploded battery, so the decrease of the severity of battery explosion and the lower explosion injection pressure. Another one is that only when the internal pressure is greater than the external pressure will the explosion occur. The pressure difference of the battery at 61 kPa is greater than that at 96 kPa, which will lead to the continuous release of gas from the cathode. And because of the leakage of gas before the thermal runaway, the amount of gas ejected during the explosion is small. Therefore, the explosion pressure at 61 kPa is smaller than that at 96 kPa.
The maximum explosion pressure variation of four cases under 96 kPa and 61 kPa: I, II, III, and IV is the serial number of batteries, and they are separated by different shapes.
The lithium-ion battery thermal runaway reaction can be regarded as a type of explosion. Therefore, to compare the harmlessness of the battery explosion under different initial pressures, the reaction heat of the battery explosion is calculated and converted into TNT equivalent. The reaction heat of battery explosion can be calculated by Eq. 5, ω is the mass of TNT that is transferred from the heat of combustion to that of TNT, which is calculated by Eq. 6.20
| \begin{equation} \Delta H = C_{\text{p}}m_{\text{cell}}(T_{\text{max}} - T_{0}) \end{equation} | (5) |
| \begin{equation} \omega = \frac{\Delta H}{H_{\text{TNT}}} \end{equation} | (6) |
| SOC/% | Pressure/kPa | Experiment setting |
Battery Serial Number |
mass/g | Cρ/J g−1 k−1 | T0/°C | Tmax/°C | ΔH/kJ | ω/g |
|---|---|---|---|---|---|---|---|---|---|
| 100 % | 96 | Case A | I | 45.5 | 1.1 | 94 | 736 | 36.8 | 8.3 |
| Case B | I | 45.5 | 1.1 | 122 | 634 | 31.7 | 7.1 | ||
| II | 45.5 | 1.1 | 121 | 632 | 31.6 | 7.1 | |||
| Case C | I | 45.5 | 1.1 | 148 | 611 | 30.6 | 6.9 | ||
| II | 45.5 | 1.1 | 123 | 568 | 28.4 | 6.4 | |||
| III | 45.5 | 1.1 | 138 | 554 | 27.7 | 6.2 | |||
| Case D | I | 45.5 | 1.1 | 132 | 619 | 31.0 | 7.0 | ||
| II | 45.5 | 1.1 | 154 | 599 | 30.0 | 6.8 | |||
| III | 45.5 | 1.1 | 146 | 593 | 29.7 | 6.7 | |||
| IV | 45.5 | 1.1 | 189 | 573 | 28.7 | 6.5 | |||
| 61 | Case A | I | 45.5 | 1.1 | 221 | 820 | 30.0 | 6.8 | |
| Case B | I | 45.5 | 1.1 | 189 | 710 | 26.1 | 5.9 | ||
| II | 45.5 | 1.1 | 172 | 747 | 28.8 | 6.5 | |||
| Case C | I | 45.5 | 1.1 | 170 | 715 | 27.3 | 6.2 | ||
| II | 45.5 | 1.1 | 204 | 730 | 26.3 | 5.9 | |||
| III | 45.5 | 1.1 | 201 | 719 | 25.9 | 5.8 | |||
| Case D | I | 45.5 | 1.1 | 223 | 760 | 26.9 | 6.1 | ||
| II | 45.5 | 1.1 | 203 | 668 | 23.3 | 5.3 | |||
| III | 45.5 | 1.1 | 201 | 691 | 24.5 | 5.5 | |||
| IV | 45.5 | 1.1 | 233 | 734 | 25.1 | 5.7 |
It can be seen from Table 3 that with the increase of initial pressure, the TNT equivalent of battery explosion also increases. In Case A, the destructive power of a single lithium-ion battery is greater than that of other cases, and the destructive power of the lithium-ion battery at 96 kPa is equivalent to 8.3 g TNT equivalent, about 1.2 times the initial pressure of 61 kPa. In addition, from the perspective of TNT equivalent, the TNT equivalent of battery explosion at 96 kPa is about 1–1.3 times that at 61 kPa. This is mainly attributed to the initial low-pressure environment that inhibits the internal chemical reaction of lithium-ion batteries during thermal runaway. And under 96 kPa, the adequacy of the internal chemical reaction of the battery during thermal runaway is lower, causing the decrease of the heat generated by itself and the corresponding decrease of the heat released to the outside, thus resulting in the reduction of TNT equivalent of battery ignition and explosion. In addition, the increase in the number of batteries leads to a longer distance of heat conduction, coupled with partial heat loss and inadequate combustion of the ejected flammable gas and electrolyte, resulting in a greater drop in oxygen content in the pressure barrel. These cause the battery to explode less violently, resulting in a lower blast ejection pressure. Finally, the TNT equivalent of a single battery in the battery pack decreases.
3.3 The mass lossThe mass loss of batteries before and after the experiment is shown in Table 4. The mass loss percent is expressed as m % and the equation is shown in Eq. 7. m is the mass before the experiment. m′ is the mass after the experiment.
| \begin{equation} \Delta \text{m}(\%) = \frac{m - m'}{m} \times 100 \end{equation} | (7) |
| Experiment setting |
Initial pressure /kPa |
m/g | Battery I | Battery II | Battery III | Battery IV | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| mass loss/g |
m/% | mass loss/g |
m/% | mass loss/g |
m/% | mass loss/g |
m/% | |||
| Case A | 96 | 46 | 16.50 | 35.9 | — | — | — | |||
| 61 | 46 | 14.80 | 32.2 | — | — | — | ||||
| Case B | 96 | 46 | 16.50 | 35.9 | 16.66 | 36.2 | — | — | ||
| 61 | 46 | 16.07 | 34.9 | 15.38 | 33.4 | — | — | |||
| Case C | 96 | 46 | 15.85 | 34.5 | 17.00 | 37.0 | 16.85 | 36.6 | — | |
| 61 | 46 | 15.77 | 34.3 | 16.42 | 35.7 | 16.00 | 34.8 | — | ||
| Case D | 96 | 46 | 16.58 | 36.0 | 16.50 | 35.9 | 16.50 | 35.9 | 16.00 | 34.8 |
| 61 | 46 | 16.00 | 34.8 | 16.06 | 34.9 | 15.61 | 33.9 | 14.80 | 32.2 | |
The mass loss is similar in four cases. The average mass loss under 61 kPa is less than that under 96 kPa. Under 61 kPa, the oxygen concentration is less. The internal chemical reaction rate of the battery is lower. Thus the intensity of thermal runaway under 61 kPa is weaker. The amount of released gas and ejected material is less during the thermal runaway. The mass loss under 61 kPa is 0.08–1.7 g lower than that under 96 kPa.
In this paper, a series of experiments on thermal runaway characteristics of lithium-ion batteries under 61 kPa and 96 kPa are carried out to analyze the real-time temperature, explosion pressure, and mass loss. The conclusions are as follows.
This work was partly supported by the key project of National Natural Science Foundation of China (U2033206) and the Scientific Research Fund of Civil Aviation Flight University of China (J2020-110).
Quanyi Liu: Project administration (Lead)
Qian Zhu: Investigation (Equal), Writing – original draft (Lead), Writing – review & editing (Equal)
Wentian Zhu: Investigation (Equal), Writing – review & editing (Equal)
Xiaoying Yi: Investigation (Equal), Writing – review & editing (Equal)
Xu Han: Investigation (Equal), Writing – review & editing (Equal)
The authors declare no conflict of interest in the manuscript.
National Natural Science Foundation of China Key Project: U2033206
Scientific Research Fund of Civil Aviation Flight University of China: J2020-110
The content of this paper has been published by Xu Han as a Ph.D. thesis at the Civil Aviation Flight University of China in 2019. https://kns.cnki.net/kcms/detail/detail.aspx?dbcode=CMFD&dbname=CMFD201902&filename=1019128414.nh&v=MzIyNTVUcldNMUZyQ1VSN2lmWStSbUZ5emhWci9KVkYyNkY3SzZGdFhOcTVFYlBJUjhlWDFMdXhZUzdEaDFUM3E=.
