Method and device for measuring thermal runaway characteristic of battery

Abstract

The invention provides a method for measuring the thermal runaway characteristic of a battery, which is used in the technical field of accurate measurement and thermal runaway testing of the volume, components and content of produced gas in the thermal runaway process of the battery, and the measurement method comprises the following steps: step 1, installing a test object in an experiment cabin, and carrying out pre-inflation replacement on the experiment cabin, the gas environment in the experiment module is a pre-inflation environment in a normal pressure state; 2, when the initial temperature value in the cabin is equal to the initial temperature of the surface of the battery, the battery is controlled to be heated or overcharged through an adapter on the experiment cabin, and the current temperature value in the cabin and the temperature value of the surface of the battery are recorded; and 3, recording the pressure value and the temperature value of the battery in the cabin in real time during thermal runaway, and calculating the gas production rate of the battery. According to the method, the gas production volume and components in thermal runaway are accurately measured, and the gas production rate and the total heat release amount in the thermal runaway period are calculated; the multi-dimensional characteristics of the thermal runaway behavior are obtained through one-time testing, and the thermal runaway safety of the battery is comprehensively evaluated.

Description

Technical Field

[0001] The present invention relates to a method and device for measuring the characteristics of battery thermal runaway, belonging to the technical field of thermal runaway testing. Background Art

[0002] Testing and analyzing the characteristics during the battery runaway process, especially parameters such as the total gas production volume, gas production rate, total heat release, gas production components and contents, is crucial for early warning of thermal runaway, assessment of the fire hazard of thermal runaway, and design of fire protection systems.

[0003] The premise of analyzing the characteristics of thermal runaway is to effectively and accurately collect the gas produced during the thermal runaway process. Currently, the gas produced during thermal runaway is mainly collected based on a closed thermal runaway experimental chamber. The volume of gas produced during thermal runaway is calculated by converting the gas pressure inside the chamber. However, due to the large variety of thermal runaway gases and the different densities of different gases, it is easy for the gas to form a stratified structure inside the chamber, resulting in a large error between the subsequent gas composition analysis results and the actual results. In addition, since the pressure sensor is a single-point measurement and the gas densities are different, the volume of gas produced obtained by converting the gas pressure is inaccurate. Since the temperature of the battery is very high during thermal runaway and strong heat transfer occurs when there is a temperature difference with the external environment, therefore, by heating and insulating the external environment, the heat transfer during the battery thermal runaway process can be effectively avoided, and thus the total heat release can be calculated. In addition, record the change in the pressure value inside the closed chamber, and the gas production rate during the battery thermal runaway can be calculated through the ideal gas state equation. Summary of the Invention

[0004] Aiming at the deficiencies of the above-mentioned prior art, the purpose of the present invention is to provide a method and device for measuring the characteristics of battery thermal runaway.

[0005] According to the embodiment of the present invention, the first solution is provided as follows:

[0006] A method for measuring the characteristics of battery thermal runaway, which is used to accurately measure the gas production volume, components and contents during the battery thermal runaway process. The steps of the measurement method are as follows:

[0007] Step 1, install the test object in the experimental chamber, and the experimental chamber is pre-inflated and replaced so that the gas environment in the experimental chamber is a pre-inflated environment under normal pressure;

[0008] Step 2, when the initial temperature value inside the chamber is equal to the initial temperature on the battery surface, control the heating or overcharging of the battery through the adapter on the experimental chamber, and record the current temperature value inside the chamber and the temperature value on the battery surface;

[0009] Step 3, record the pressure value and temperature value inside the chamber during the battery thermal runaway in real time, and calculate the gas production rate of the battery through the formula PV = nRT.

[0010] Further, in step 4, start the stirrer in the experimental chamber to fully stir the gas in the thermal runaway experimental chamber;

[0011] In step 5, when the current temperature value in the chamber reaches the initial temperature value, turn off the stirrer;

[0012] In step 6, connect a gas collection bag at the outlet of the experimental chamber. The total amount of gas filled into the gas collection bag is the total amount of gas generated during the thermal runaway of the battery;

[0013] In step 7, analyze the sampled gas in the collection bag using a gas chromatograph, and calculate the components and contents of the gas generated during the battery runaway.

[0014] Further, when adiabatic conditions are required for the experiment, add the following steps in step 2:

[0015] When the battery surface temperature value > the current temperature value in the chamber, start the thermal compensation device in the chamber to heat the chamber so that the current temperature in the chamber reaches the battery surface temperature value, thereby minimizing the heat transfer between the battery and the outside;

[0016] When the current temperature value in the chamber reaches the highest temperature of the battery surface, turn off the heater device; at this time, the total heat release during the thermal runaway of the battery can be calculated.

[0017] Further, in step 1, the precharged gas can be nitrogen, inert gas.

[0018] Further, the pressure resistance of the actual chamber is greater than or equal to 2 MPa;

[0019] The experimental chamber maintains a sealing index that the pressure value after vacuum is lower than 500 Pa and the holding time is greater than 24 hours;

[0020] The temperature sensors for measuring temperature are all reference-class platinum resistance temperature sensors.

[0021] According to the implementation scheme of the present invention, another scheme is provided as follows:

[0022] A device for measuring the thermal runaway characteristics of a battery, the main body being an experimental chamber, the experimental chamber including a lower chamber and an upper cover, and the lower chamber and the upper cover are connected to ensure the pressure resistance performance and sealing performance of the experimental chamber;

[0023] The upper cover is used to place and take out the experimental object, and the outer wall of the experimental chamber is wrapped with a heat insulation device to isolate the heat exchange between the experimental chamber and the external environment;

[0024] A first valve is connected through the side wall of the lower cabin. On the other side of the first valve, a second valve and a pre-inflation gas cylinder are respectively connected; the second valve is connected to a vacuum pump; the top of the upper cover is connected with a one-way valve for releasing the gas in the experimental cabin, and on the other side of the one-way valve, a gas flow meter is installed for calculating the volume of the released gas;

[0025] A pressure sensor and a first temperature sensor are installed on the side wall of the experimental cabin; they are used to measure the pressure and temperature of the gas environment in the experimental cabin;

[0026] A stirrer is installed on the inner side of the upper cover of the experimental cabin. An adapter is installed on the side wall of the experimental cabin. The adapter is used to connect a short-circuit device or a heating device to trigger thermal runaway of the test object;

[0027] There is a heat-insulating block for placing the experimental object at the lower part of the lower cabin of the experimental cabin; the experimental cabin is also provided with a second temperature sensor for measuring the surface temperature of the experimental object.

[0028] Furthermore, a thermal compensation device is arranged in the experimental cabin. The thermal compensation device is associated and controlled with the second temperature sensor and the first temperature sensor, and the control condition is that the temperature difference between the second temperature sensor and the first temperature sensor is the smallest.

[0029] Furthermore, the stirrer adopts a fan blade or a circulation fan;

[0030] The short-circuit device adopts an indirect short-circuit method using an electromagnetic relay or a direct short-circuit method of directly connecting a wire. The heating device adopts a resistance wire heating or an infrared heating method. The heating device is installed on the side wall of the experimental object.

[0031] Furthermore, the pressure resistance of the experimental cabin is greater than or equal to 2 MPa;

[0032] The sealing index of the experimental cabin is that the pressure value after vacuum is lower than 500 Pa and the holding time is greater than 24 hours;

[0033] The temperature sensors for measuring temperature are all reference-grade platinum resistance temperature sensors.

[0034] Furthermore, a sample placement door is also arranged on the upper cover of the experimental cabin. The sample placement door is opened near the one-way valve.

[0035] Compared with the prior art, the beneficial effects of the independent claim of the technical solution provided by this application.

[0036] 1. The present invention uses a stirrer to fully mix the gas in the cavity, which can achieve the full mixing of gases with different densities and improve the accuracy of analysis;

[0037] 2. The present invention can break through the limitations of traditional single-point pressure sensors and obtain the total gas production during the battery thermal runaway process without any calculation.

[0038] 3. The present invention can accurately measure the gas production volume and gas components during battery thermal runaway, and the gas production rate and total heat release during battery thermal runaway can be obtained through calculation.

[0039] 4. The present invention can obtain multi-dimensional characteristics of battery thermal runaway behavior through a single test and comprehensively evaluate the safety of battery thermal runaway. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0041] Figure 1 It is a structural diagram of a battery thermal runaway characteristic measurement device in an embodiment.

[0042] Reference Signs:

[0043] 1. First valve; 2. Second valve; 3. Vacuum pump; 4. Pressure sensor; 5. Pre-charged gas cylinder; 6. Check valve; 7. Gas flow meter; 8. Adapter; 9. Battery; 10. Stirrer; 11. First temperature sensor; 12. Heat insulation device; 13. Second temperature sensor; 14. Thermal compensation device; 15. Heat insulation block; 16. Lower cabin; 17. Upper cover. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] In order to enable those skilled in the art to better understand the technical solutions in the present application, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0045] Embodiment 1

[0046] As Figure 1 shown,

[0047] The present invention provides a device for measuring battery thermal runaway characteristics. The experimental cabin is a pressure-resistant cabin, and the pressure-resistant cabin provides space and a test environment for measuring battery thermal runaway characteristics.

[0048] The main body is the experimental cabin, which includes the lower cabin 16 and the upper cover 17. The connection method between the lower cabin 16 and the upper cover 17 can ensure the pressure resistance and sealing performance of the experimental cabin. The connection method can be a threaded connection with a sealing ring or a snap connection with a sealing ring.

[0049] The upper cover is used to place and remove the experimental object. The outer wall of the experimental cabin is wrapped with a heat insulation device 12 to isolate the heat exchange between the experimental cabin and the external environment.

[0050] A first valve 1 (gas channel) is connected through the side wall of the lower cabin 16. The other side of the first valve 1 is respectively connected to a second valve 2 (for controlling vacuum) and a pre-charged gas cylinder 5; the second valve 2 is connected to a vacuum pump 3.

[0051] The valve 1 and the valve 2 can be replaced by a three-way selection valve.

[0052] A one-way valve 6 is connected to the top of the upper cover 17 for releasing the gas in the experimental cabin. The other side of the one-way valve 6 is equipped with a gas flow meter 7 for calculating the volume of the released gas.

[0053] A pressure sensor 4 and a first temperature sensor (cabin gas temperature) are installed on the side wall of the experimental cabin; they are used to measure the pressure and temperature of the gas environment in the experimental cabin.

[0054] A stirrer 10 is installed on the inner side of the experimental cabin of the upper cover 17. The stirrer 10 can adopt a fan blade solution or a circulating fan method.

[0055] An adapter 8 is installed on the side wall of the experimental cabin. The adapter 8 is used to connect a short-circuit device or a heating device to trigger thermal runaway of the test object.

[0056] The short-circuit device can adopt an indirect short-circuit method using an electromagnetic relay or a direct short-circuit method of directly connecting wires. The heating device can adopt a resistance wire heating or an infrared heating method.

[0057] The heating device is installed on the side wall of the test object.

[0058] It is used to perform a short-circuit operation on the experimental object or a heating operation on the experimental object.

[0059] There is a heat insulation block 15 for placing the experimental object at the lower part of the lower cabin of the experimental cabin;

[0060] The experimental object is a battery 9. During the experiment, in order to ensure that the heat of the battery is not consumed by the experimental cabin, the battery 9 needs to be placed on the heat insulation block 15 for the experiment. When necessary, a heat insulation block can be used to wrap the battery.

[0061] During the experiment, a second temperature sensor 13 is mounted on the surface of the battery 9 to detect the surface temperature of the battery. If a heating device is used to trigger thermal runaway of the battery, the second temperature sensor 13 is mounted on the opposite side of the heating device to minimize the influence of the heating device on the measured temperature.

[0062] Furthermore, in order to meet the requirement of testing the thermal runaway characteristic parameters of the battery under adiabatic conditions, a heat compensation device 14 is provided in the experimental chamber. The heat compensation device 14 is associated with the second temperature sensor 13 and the first temperature sensor 11 for control, and the control condition is that the temperature difference between the second temperature sensor 13 and the first temperature sensor 11 is minimized.

[0063] For example, record the temperature value T2 of the temperature sensor 11 and the temperature value T3 of the center temperature sensor 13 on the surface of the battery 9 at this time. When T3 > T2, start the heating device 14 in the chamber and heat the chamber until T2 approaches T3, so as to minimize the heat transfer between the battery and the outside.

[0064] The highest temperature T4 on the surface of the battery. After the temperature sensor 11 reaches the highest temperature T4, turn off the heater device 14.

[0065] When the rigidity of the housing of some batteries is insufficient, for example, when conducting experiments on soft-pack batteries, the above scheme can be improved.

[0066] Open a small sample placement door on the upper cover of the experimental chamber. After processing using the above steps without placing the battery, then open the sample placement door, place the battery, and then open the first valve 1 and the one-way valve 6. Open the valve of the pre-inflation device 5 to displace the possible incoming air through the flow of gas.

[0067] It should be noted that the sample placement door is opened near the one-way valve 6 while ensuring the pressure resistance performance of the experimental chamber.

[0068] The above temperature sensors and pressure sensors can all use a paperless recorder to record data or collect data through a data interface using a computer, and control the heating device and the heat compensation device.

[0069] Embodiment 2

[0070] The present invention also provides a method for measuring the thermal runaway characteristics of a battery using the above battery thermal runaway characteristic measurement device, which is used to accurately measure the gas volume, components, and content during the thermal runaway process of the battery. The steps of the measurement method are as follows:

[0071] Step 1: Install the test object in the experimental chamber, and perform pre-inflation replacement on the experimental chamber so that the gas environment in the experimental chamber is a pre-inflation environment under normal pressure.

[0072] The method for making the gas environment in the experimental chamber a pre-inflation environment under normal pressure is as follows:

[0073] Step 1-1: Open the first valve 1 and the second valve 2, start the vacuum pump 3, evacuate the thermal runaway experimental chamber. Stop the vacuum pump when the pressure value P recorded by the pressure sensor in the chamber is lower than 500 Pa, and close valve 2.

[0074] Step 1-2: Open the valve of the nitrogen cylinder 5, and introduce pre-inflation into the thermal runaway experimental chamber through valve 1. When the pressure in the thermal runaway experimental chamber detected by the pressure sensor 4 is slightly greater than normal pressure, close the nitrogen cylinder valve and valve 1.

[0075] Step 1-3: Open the one-way valve 6 of the thermal runaway experimental chamber to release the nitrogen in the chamber. The nitrogen in the chamber passes through the one-way valve 6 and then through the gas flowmeter 7. When the reading of the gas flowmeter 7 no longer changes, close the one-way valve 6, and at the same time zero the reading of the gas flowmeter 7. In addition, record the current temperature value T1 in the chamber through the temperature sensor 11, and record the battery surface temperature T2 through the temperature sensor 13.

[0076] When the rigidity of the housing of some batteries is insufficient, for example, when conducting experiments on soft-pack batteries, the above scheme can be improved.

[0077] Open a small sample placement door on the upper cover of the experimental chamber. After processing using the above steps without putting the battery, the following steps can be carried out.

[0078] Step 1-4: Open the sample placement door to put in the battery, then open the first valve 1 and the one-way valve 6, open the valve of the pre-inflation 5, displace the possible entering air through the flow of the gas, and close the pre-inflation 5, the first valve 1 and the one-way valve 6.

[0079] In step 1, testing the pressure is not necessary. The one-way valve 6 can be directly opened while introducing nitrogen, and it can be judged whether the pressure in the thermal runaway experimental chamber has exceeded normal pressure by observing the reading of the gas flowmeter 7.

[0080] Step 3: Record the pressure value P and the temperature value during the thermal runaway of the battery in the chamber in real time. The amount of gas substance in the chamber at each moment can be calculated using the formula PV = nRT, and further the gas production rate of the battery can be calculated. The inner cavity volume of the experimental chamber is calibrated in advance.

[0081] Step 4: Turn on the stirrer 10 to fully stir the gas in the thermal runaway experimental chamber.

[0082] Step 5: When the temperature sensor 11 reaches the temperature value T1, turn off the stirrer 10.

[0083] Step 6: Connect a gas collection bag to the outlet of the one-way valve 6 and open the one-way valve 6. At this time, since a large amount of combustible and explosive gas is produced due to battery thermal runaway, the pressure in the thermal runaway test chamber is greater than atmospheric pressure, and the gas in the chamber will pass through the one-way valve 6 and the gas flowmeter into the gas collection bag. When the reading of the gas flowmeter no longer changes, close the one-way valve and record the total volume of gas V1 of the gas flowmeter. V1 is the total gas production during battery thermal runaway, with the unit of L.

[0084] In step 6, the reading of the gas flowmeter does not need to be reset to zero. The reading V0 of the gas flowmeter before the one-way valve is opened can be recorded, with the unit of L. The total gas production during the battery thermal runaway process can be obtained by the method of V1 - V0.

[0085] It should be noted here that if considering the test accuracy of the gas flowmeter or the starting pressure problem, the volume of the gas introduced into the collection bag can be calibrated by the water displacement method.

[0086] For example, close and seal the collection bag, immerse it in a container filled with water, and measure the volume of the discharged water to obtain the volume of the gas filled in the collection bag.

[0087] Or, squeeze out the gas in the collection bag and use a micro flowmeter to measure the volume of the discharged gas. The operation of step 7 can be carried out synchronously during the exhaust.

[0088] Step 7: Analyze the sampled gas in the collection bag using a gas chromatograph and calculate the gas components and contents produced by battery runaway.

[0089] It should be noted that the gas components and contents obtained by the gas chromatograph test need to be converted after excluding the components and contents of the precharged gas to be the gas components and contents produced by battery runaway.

[0090] It should be noted that in step 1, the precharged gas can be nitrogen, inert gas, or air.

[0091] However, if it is air, the out-of-control state of the actual use environment can be approximately collected for the final reaction gas. However, since the combustible gas released during battery thermal runaway reacts with the oxygen in the air, the finally collected gas cannot fully reflect the gas released by the battery itself, which can be used as another scheme for testing the characteristics of battery thermal runaway.

[0092] The pressure resistance of the thermal runaway test chamber is greater than or equal to 2 MPa;

[0093] The sealing index of the thermal runaway test chamber is that the pressure value after vacuum is lower than 500 Pa and the holding time is greater than 24 hours;

[0094] The temperature sensors used for measuring temperature are all reference-grade platinum resistance temperature sensors;

[0095] In another embodiment, when adiabatic conditions are required for the experiment, the following steps are added in Step 2:

[0096] Step 2-1, when T1 = T2, heat or overcharge the battery 9 through the adapter 8 on the thermal runaway test chamber, and record the temperature value T2 of the temperature sensor 11 and the temperature value T3 of the center temperature sensor 13 on the surface of the battery 9 at this time. When T3 > T2, start the in-cabin heating device 14 to heat the inside of the cabin until T2 approaches T3, so as to minimize the heat transfer between the battery and the outside;

[0097] It should be noted that for thermal runaway, in addition to being triggered by a short circuit, sometimes heating by an electric heating plate is also required. Therefore, the temperature at the time of runaway is used as the starting temperature, and the surface temperature of the battery is used as the calculation standard. Since the specific heat capacity of the gas is relatively low, the heat of gas heat exchange is ignored here.

[0098] Step 2-2, the highest temperature T4 on the surface of the battery. After the temperature sensor 11 reaches the highest temperature T4, turn off the heater device 14; at this time, the total heat release E during the thermal runaway of the battery can be calculated as E = c * m * (T4 - T1), where c is the specific heat capacity of the battery and m is the mass of the battery.

[0099] It should be noted that here, the mass of the battery and the temperature rise of the battery are used as the basis for calculating the total heat release, because the mass loss caused by gas production is small, and the generated gas is also a high-temperature gas. If the temperature change of the cabin gas is ignored and the heating method of the in-cabin heating device 14 is not adopted, comparative experiments on different test objects under the same conditions can be carried out.

[0100] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combinations of these technical features do not conflict, they should all be considered as the scope described in this specification.

[0101] The above-described embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for measuring the characteristics of battery thermal runaway, which is used to accurately measure the volume, components and content of the gas generated during the battery thermal runaway process. It is characterized in that, The steps of the measurement method are as follows: Step 1: Install the test object in the experimental chamber. The experimental chamber is pre-inflated and replaced so that the gas environment in the experimental chamber is a pre-inflated environment under normal pressure; Step 2: When the initial temperature value in the chamber is equal to the initial temperature on the battery surface, control the heating or overcharging of the battery through the adapter on the experimental chamber, and record the current temperature value in the chamber and the temperature value on the battery surface; Step 3: Record the pressure value and temperature value during the battery thermal runaway in the chamber in real time, and calculate the gas production rate of the battery.

2. The method for measuring the characteristics of battery thermal runaway according to claim 1, characterized in that, Step 4: Start the stirrer in the experimental chamber to fully stir the gas in the thermal runaway experimental chamber; Step 5: When the current temperature value in the chamber reaches the initial temperature value, turn off the stirrer; Step 6: Connect a gas collection bag at the outlet of the experimental chamber. The total amount of gas filled into the gas collection bag is the total gas production during the battery thermal runaway; Step 7: Analyze the sample gas in the collection bag using a gas chromatograph, and calculate the components and content of the gas generated during the battery runaway through calculation.

3. The method for measuring the characteristics of battery thermal runaway according to claim 1, characterized in that, When adiabatic conditions are required for the experiment, the following steps are added in Step 2, When the temperature value on the battery surface > the current temperature value in the chamber, start the thermal compensation device in the chamber to heat the chamber so that the current temperature in the chamber reaches the temperature value on the battery surface, thereby minimizing the heat transfer between the battery and the outside; After the current temperature value in the chamber reaches the highest temperature on the battery surface, turn off the heater device; the total heat release during the battery thermal runaway can be calculated.

4. The method for measuring the characteristics of battery thermal runaway according to claim 1, characterized in that, In Step 1, the pre-charged gas can be nitrogen, inert gas.

5. The method for measuring the characteristics of battery thermal runaway according to claim 1, characterized in that, The pressure resistance of the actual chamber is greater than or equal to 2 MPa; The sealing index of the experimental chamber is that the pressure value after vacuum is lower than 500 Pa and the holding time is greater than 24 hours; All the temperature sensors used for measuring temperature are reference-class platinum resistance temperature sensors.

6. A battery thermal runaway characteristic measurement device, characterized in that The main body is an experimental chamber; The experimental chamber includes a lower chamber and an upper cover. The lower chamber and the upper cover are connected to ensure the pressure resistance and sealing performance of the experimental chamber; The upper cover is used to place and remove the test object. The outer wall of the experimental chamber is wrapped with a heat insulation device to isolate the heat exchange between the experimental chamber and the external environment; A first valve is connected through the side wall of the lower chamber. The other side of the first valve is respectively connected to a second valve and a pre-inflation gas cylinder; the second valve is connected to a vacuum pump; a one-way valve is connected to the top of the upper cover for releasing the gas in the experimental chamber, and a gas flow meter is installed on the other side of the one-way valve for calculating the volume of the released gas; A pressure sensor and a first temperature sensor are installed on the side wall of the experimental chamber; used to measure the pressure and temperature of the gas environment in the experimental chamber. A stirrer is installed inside the experimental chamber of the upper cover, and an adapter is installed on the side wall of the experimental chamber. The adapter is used to connect a short-circuit device or a heating device to trigger thermal runaway of the test object. There is a heat-insulating block for placing the experimental object at the lower part of the lower chamber of the experimental chamber. The experimental chamber is also provided with a second temperature sensor for measuring the surface temperature of the experimental object.

7. The battery thermal runaway characteristic measurement device according to claim 6, characterized in that A thermal compensation device is arranged in the experimental chamber. The thermal compensation device is associated and controlled with the second temperature sensor and the first temperature sensor, and the control condition is that the temperature difference between the second temperature sensor and the first temperature sensor is the smallest.

8. The battery thermal runaway characteristic measurement device according to claim 6, characterized in that The stirrer uses a fan blade or a circulation fan; The short-circuit device adopts the method of indirect short-circuit with an electromagnetic relay or the method of direct short-circuit by directly connecting a wire. The heating device adopts the method of resistance wire heating or infrared heating, and the heating device is installed on the side wall of the experimental object.

9. The battery thermal runaway characteristic measurement device according to claim 6, characterized in that The pressure resistance of the experimental chamber is greater than or equal to 2 MPa; The sealing index of the experimental chamber is that the pressure value after vacuum is lower than 500 Pa and the holding time is greater than 24 hours; All the temperature sensors for measuring temperature are reference-grade platinum resistance temperature sensors.

10. The battery thermal runaway characteristic measurement device according to claim 6, characterized in that A sample placement door is further arranged on the upper cover of the experimental chamber, and the sample placement door is opened near the one-way valve.

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