Battery Thermal Runaway Test Method and Battery Thermal Runaway Test Equipment

Abstract

Embodiments of the present application provide a battery thermal runaway test method, device, apparatus, and computer-readable storage medium. The battery thermal runaway test method is applied to a battery thermal runaway test device, which includes a box body and a pressure relief valve disposed on the box body. The pressure relief valve is used to communicate the inner cavity of the box body with the outside. The battery thermal runaway test method includes: when the battery placed in the box body undergoes thermal runaway, obtaining the air pressure in the box body as the runaway air pressure value; determining the exhaust rate of the pressure relief valve according to the runaway air pressure value; and determining the gas production rate when the battery undergoes thermal runaway according to the exhaust rate. The above battery thermal runaway test method has relatively accurate test results for the gas production rate of the battery in the thermal runaway state.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and in particular to a battery thermal runaway test method, device, apparatus and computer-readable storage medium. Background Art

[0002] In recent years, thermal runaway accidents of electric vehicle battery systems have emerged in an endless stream, endangering people's lives and property safety, and at the same time hitting people's confidence in electric vehicles. In particular, battery thermal runaway accidents have attracted much attention.

[0003] During the occurrence of thermal runaway of a lithium-ion battery, a series of chemical reactions will occur inside the battery. These reactions generate a large amount of heat and are accompanied by the generation of a lot of combustible gases, ultimately leading to thermal runaway of the battery and causing safety accidents such as fire and explosion. Therefore, it is necessary to confirm the gas production rate during battery thermal runaway and select a protective structure such as a battery box with appropriate specifications and strength to ensure the safety of the battery system. However, in related technologies, the calculation of the gas production rate of the battery under thermal runaway conditions only relies on theoretical calculations and cannot be combined with the actual thermal runaway state. Therefore, the accuracy of the obtained gas production rate is relatively low. Summary of the Invention

[0004] Embodiments of the present application provide a battery thermal runaway test method, device, apparatus and computer-readable storage medium.

[0005] In a first aspect, embodiments of the present application provide a battery thermal runaway test method. The battery thermal runaway test method includes: when a battery placed in a box of a battery thermal runaway test device undergoes thermal runaway, obtaining the air pressure in the box as a runaway air pressure value; determining the exhaust rate of a pressure relief valve provided in the box and communicating the inner cavity of the box with the outside according to the runaway air pressure value; and determining the gas production rate during battery thermal runaway according to the exhaust rate.

[0006] In a second aspect, embodiments of the present application further provide a battery thermal runaway test device, including a box, a pressure sensor, a pressure relief valve and a controller. The detection end of the pressure sensor is located inside the box, and the pressure relief valve is connected to the box; the pressure relief valve can discharge the gas in the box to the outside. The controller is electrically connected to the pressure sensor. The controller can, when a battery placed in the box undergoes thermal runaway, obtain the air pressure in the box as a runaway air pressure value; determine the exhaust rate of the pressure relief valve according to the runaway air pressure value; and determine the gas production rate during battery thermal runaway according to the exhaust rate.

[0007] In an embodiment of the present invention, the battery thermal runaway test method can calculate the gas generation rate during battery thermal runaway more accurately by collecting the air pressure value inside the box. Meanwhile, during the test, the pressure relief valve is used to connect the inner cavity of the box with the outside world. When the battery undergoes thermal runaway, the gas generated will leak to the outside through the pressure relief valve, which can effectively relieve the excessive air pressure inside the box, thereby avoiding additional temperature rise, and maintaining the temperature inside the box within a predictable range, and avoiding the influence of high temperature on the test results.

[0008] In addition, it further ensures that the gas generation rate during battery thermal runaway has a high degree of accuracy. In the application of the test method provided in the embodiments of the present application, after mastering a relatively accurate gas generation rate during battery thermal runaway, it is beneficial to reasonably select the number and specifications of the explosion-proof valves of the battery pack, ensure safe pressure relief when the battery undergoes thermal runaway, and ultimately ensure the safety of the battery system. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] To more clearly illustrate the technical solutions of the present application, the drawings required for the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0010] Figure 1 It is a schematic diagram of the overall structure of a battery thermal runaway test device provided by an embodiment of the present application.

[0011] Figure 2 is Figure 1 A schematic diagram of the structure of placing the battery thermal runaway test device shown into the battery to be tested.

[0012] Figure 3 It is a schematic flowchart of a battery thermal runaway test method provided by an embodiment of the present application.

[0013] Figure 4 is Figure 3 A mapping relationship diagram between air pressure and exhaust rate of the battery thermal runaway test method shown.

[0014] Figure 5 It is a schematic flowchart of a battery thermal runaway test method provided by another embodiment of the present application.

[0015] Figure 6 is Figure 5 A runaway air pressure curve diagram of the battery thermal runaway test method shown.

[0016] Figure 7 It is a block diagram of a battery thermal runaway test device provided by an embodiment of the present application.

[0017] Figure 8 It is a block diagram of a module of a computer-readable storage medium provided by an embodiment of the present application. Detailed implementation manners

[0018] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present application.

[0019] Please refer to Figure 1 , an embodiment of the present application provides a battery thermal runaway test device 100. The battery thermal runaway test device 100 can be used to execute a battery thermal runaway test method to test the gas production rate u of a battery during thermal runaway.

[0020] In this embodiment, the battery thermal runaway test device 100 may include a box body 10, a pressure sensor 30, a pressure relief valve 50, and a controller 70.

[0021] In this embodiment, the specific structure of the box body 10 may be substantially the same as the actual battery box configured with the battery under test 13. For example, the box body 10 may include a top plate 12, a bottom plate 14, and four side plates 16. The four side plates 16 are sequentially connected end to end to form a tubular shape that penetrates up and down. The top plate 12 is connected to the top ends of the four side plates 16, and the bottom plate 14 is connected to the bottom of the four side plates 16 and is opposite to the top plate 12. The top plate 12, the bottom plate 14, and the four side plates 16 together enclose an accommodation space 18. Normally, the accommodation space 18 is a closed space. If the pressure relief valve 50 is installed on the box body 10, the accommodation space 18 communicates with the outside only through the pressure relief valve 50. This accommodation space 18 is used to accommodate the battery under test 13 during the test of the battery thermal runaway test device 100. Further, during the test, since the top plate 12 may be directly impacted by high-temperature gas, the top plate 12 may be made of steel with relatively high strength and toughness and have a certain structural strength (such as a thickness of 1 mm - 5 mm) so that the top plate 12 can withstand high temperature and strong heat shock.

[0022] Further, the battery thermal runaway test device 100 may further include a placeholder 90. The placeholder 90 is disposed in the box body 10 such that the difference between the effective volume of the box body 10 and the effective volume of the battery box of the battery under test 13 is less than or equal to a preset value. For example, the effective volume of the box body 10 is equal to the effective volume of the battery box, so as to improve the accuracy of the test results. The preset value may be 10 L (liters), which means that the difference between the effective volume of the box body 10 and the effective volume of the actually applied battery box is less than or equal to 10 L. For example, when the effective volume of the actual battery box is 120 L, the effective volume of the box body 10 may be 110 L or 130 L; in some embodiments, the preset value may be any value between 0 L and 50 L (including the endpoint values), which will not be elaborated one by one in this specification.

[0023] This application does not limit the specific structure of the placeholder 90. For example, the placeholder 90 may be a battery model, and the number of battery models may be multiple. The multiple battery models are stacked in the box body 10, and the overall shape of the stacked multiple battery models fits the inner wall of the box body. When the battery under test 13 is placed in the box body 10, the battery models may surround the battery under test 13 or be stacked on one side of the battery under test 13. In some examples, the arrangement manner of the placeholder 90 in the box body 10 is the same as the arrangement manner of the batteries in the actual battery box configured with the battery under test 13. For example, the multiple placeholders 90 may be divided into multiple groups, and the placeholders 90 in each group are arranged in sequence to form a module, and the multiple modules are arranged at intervals in the box body 10.

[0024] In this embodiment, the air pressure sensor 30 is connected to the box body 10 and has a detection end 32 for detecting the air pressure value in the box body 10. In this embodiment, the installation position of the air pressure sensor 30 on the box body 10 is not limited. For example, the air pressure sensor 30 may include a main body 31 and a detection end 32. The main body 31 may be disposed outside the box body 10, and the detection end 32 penetrates through the box body 10 and is located inside the box body 10; or the main body 31 is connected to the inner wall of the box body 10, and the detection end 32 is also located inside the box body 10. In this embodiment, the distance between the air pressure sensor 30 and the battery under test 13 (see Figure 2 ) in the box body 10 cannot be too small (for example, the distance between the two is greater than 1 / 3 of the length of the box body 10). Therefore, the air pressure sensor 30 may be disposed on one side inside the box body 10, and an installation portion for installing the battery under test 13 and the like may be provided at the middle position of the box body 10, so that the air pressure sensor 30 is as far away from the battery under test 13 as possible within the effective installation area of the box body 10, so as to reduce the impact of the airflow on the air pressure sensor 30 when the battery under test 13 undergoes thermal runaway.

[0025] This application does not limit the type of the pressure sensor 30. For example, the pressure sensor 30 can adopt a digital pressure sensor, that is, a high-precision sensor. This sensor uses MEMS (Micro-Electro-Mechanical System) technology to process a vacuum cavity and a Wheatstone bridge on a single-crystal silicon wafer. The output voltage at both ends of the Wheatstone bridge arm is proportional to the applied pressure. After temperature compensation and calibration, it has the characteristics of small size, high precision, fast response speed, and being unaffected by temperature changes. The output modes of this sensor can include two types: analog voltage output and digital signal output. Among them, the digital signal output mode is convenient for connection.

[0026] In this embodiment, the pressure relief valve 50 is connected to the box body 10, connecting the accommodation space 18 of the box body 10 with the outside. In the case where the battery 13 to be tested placed in the box body 10 undergoes thermal runaway, the pressure relief valve 50 discharges the gas in the box body 10 to the outside. To install the pressure relief valve 50, the box body 10 can be provided with an installation hole 11, and the pressure relief valve 50 is installed in the installation hole 11.

[0027] In this embodiment, the number of the pressure relief valves 50 is configured according to the gas production rate of the battery 13 to be tested in the thermal runaway state. For example, when setting up the battery thermal runaway test device 100, the gas production rate of the battery 13 can be calculated in advance, and the specifications and number of the pressure relief valves 50 corresponding to this gas production rate can be selected, so that the number of the pressure relief valves 50 matches the estimated gas production rate of the battery 13 to be tested in the thermal runaway state, thereby reducing the possibility of accidents caused by untimely pressure relief during the test and avoiding the accuracy problem caused by the gas production rate of the battery 13 being significantly greater than the exhaust rate of the pressure relief valve 50, thus improving the accuracy of the test results.

[0028] In this embodiment, the pressure relief valve 50 is a valve for safety protection. Its opening and closing member is in a normally closed state under the action of an external force. When the pressure in the box body 10 rises and exceeds a predetermined value, the pressure relief valve 50 automatically opens, and discharges gas to the outside to prevent the gas pressure in the box body 10 from exceeding the specified value. The function of the pressure relief valve 50 is to control the air pressure not to exceed the specified value, which plays an important role in protecting personal safety and the box body 10. In this embodiment, the distance between the pressure relief valve 50 and the battery 13 to be tested in the box body 10 (see Figure 2 ) cannot be too small (for example, the distance between the two is greater than 1 / 3 of the length of the box body 10). Therefore, the pressure relief valve 50 can be set on one side of the box body 10, and an installation part for installing the battery 13 to be tested can be provided at the middle position of the box body 10, etc., so that the pressure relief valve 50 is as far away from the battery 13 to be tested as possible within the effective installation part range of the box body 10, so as to reduce the impact of the airflow on the pressure relief valve 50 when the battery 13 to be tested undergoes thermal runaway, avoid the internal air pressure unevenness caused by directly receiving the impact of the airflow when the battery 13 to be tested undergoes thermal runaway, and further contribute to improving the accuracy of the air pressure detected by the pressure sensor 30.

[0029] The controller 70 is electrically connected to the air pressure sensor 30. In the case of thermal runaway of the battery placed in the box body 10, the controller 70 obtains the runaway air pressure value P in the box body 10 1 ; According to the runaway air pressure value P 1 determine the exhaust rate V of the pressure relief valve 50 1 ; According to the exhaust rate V 1 determine the gas production rate u during battery thermal runaway.

[0030] In some embodiments, the battery thermal runaway test device 100 may further include a charging circuit 110. The charging circuit 110 is electrically connected to the controller 70 and is used to charge the battery under test 13. Charge until the battery under test 13 undergoes thermal runaway. Further, a charging interface (not shown in the figure) may be provided in the box body 10, and the charging circuit 110 is connected to the charging interface. The present application does not limit the specific structure of the charging interface. For example, the charging interface may be a wired socket, a charger, or a wireless charging board, etc.

[0031] In some embodiments, the battery thermal runaway test device 100 may further include a holding device 20. The holding device 20 is used to fix the battery under test 13. The structure of the holding device 30 may be adapted to the outer shape of the battery under test 13, and its locking force and arrangement method are carried out according to the actual module design. For example, the holding device may be an installation box connected to the bottom wall of the box body 10. An installation slot for accommodating the battery under test 13 is provided in the installation box. The installation slot is adapted to the outer shape of the battery under test 13, and the battery under test 13 is in interference fit with the installation slot; Another example is that the holding device 20 may be a jaw structure connected to the bottom wall of the box body 10 or other clamping structures that can fix the battery under test 13. The holding device 20 fixes the battery under test 13 to prevent the battery under test 13 in a thermally runaway state from moving and causing safety accidents.

[0032] Based on the above battery thermal runaway test device, during the test, the battery under test 13 is placed in the box body 10, and the controller 70 controls the charging circuit 110 to charge the battery under test 13 until the battery under test 13 undergoes thermal runaway. Then, the controller 70 obtains the runaway air pressure value P in the box body 10 through the air pressure sensor 30 1 , according to the runaway air pressure value P 1 determine the exhaust rate V of the pressure relief valve 50 1 ; According to the exhaust rate V 1 , determine the gas production rate u during battery thermal runaway.

[0033] Please refer to Figure 3, based on the above battery thermal runaway test equipment, an embodiment of the present application further provides a battery thermal runaway test method. This battery thermal runaway test method is applied to the battery thermal runaway test equipment, which includes a box body and a pressure relief valve provided in the box body. The pressure relief valve is used to connect the inner cavity of the box body with the outside world; specifically in this embodiment, the method may include the following steps S1010 to step S1050.

[0034] Step S1010: When the battery placed in the box body of the battery thermal runaway test equipment undergoes thermal runaway, obtain the air pressure in the box body as the runaway air pressure value.

[0035] In this embodiment, the air pressure sensor detects the initial air pressure value P in the box body before the battery under test in the box body undergoes thermal runaway 0 , and detects the runaway air pressure value P in the box body when the battery under test is in a thermal runaway state 1 , and calculate the relative air pressure value P Δ .

[0036] Step S1030: Determine the exhaust rate of the pressure relief valve provided in the box body and connecting the inner cavity of the box body with the outside world according to the runaway air pressure value.

[0037] In some embodiments, the controller can directly determine the exhaust rate V at this runaway air pressure value P 1 according to the relationship between the runaway air pressure value P 1 and the exhaust rate V of the pressure relief valve 1 . Specifically, the controller may be pre-set with the corresponding relationship between the air pressure and the exhaust rate of the pressure relief valve (such as a mapping table or a relationship curve, etc.). After obtaining the runaway air pressure value P 1 , the corresponding exhaust rate V 1 can be directly queried by looking up the table. 1 .

[0038] In other embodiments, the exhaust rate V of the pressure relief valve 1 is determined based on the relative air pressure value P Δ , where the relative air pressure value P Δ refers to the increased air pressure value relative to the initial air pressure value P 1 in the battery thermal runaway state. After the controller obtains the runaway air pressure value P 1 , according to the initial air pressure value P 0 and the runaway air pressure value P 1 , calculate the relative air pressure value P Δ , and further determine the exhaust rate V of the pressure relief valve corresponding to this relative air pressure value P Δ according to the preset mapping relationship between air pressure and exhaust rate. 1Among them, the "mapping relationship" in the "mapping relationship between air pressure and exhaust rate" represents the exhaust rate corresponding to the pressure relief valve under different air pressure conditions, that is, it represents the exhaust rate V of the pressure relief valve 1 The corresponding relationship with the ambient air pressure of the pressure relief valve. This corresponding relationship can be the corresponding relationship of a function curve, or the point-to-point mapping relationship set by the product factory of the pressure relief valve. For example, the mapping relationship between air pressure and exhaust rate can be characterized by the relationship curve between the two, such as Figure 3 shown

[0039] Step S1050: Determine the gas production rate during battery thermal runaway according to the exhaust rate

[0040] In some embodiments, when the number of pressure relief valves installed on the box body is one, the gas production rate u during battery thermal runaway is equal to the exhaust rate V 1 equal

[0041] In other embodiments, the number of pressure relief valves installed on the box body can be more than one. The gas production rate u during battery thermal runaway is equal to the total exhaust rate V of multiple pressure relief valves 2 equal

[0042] The above battery thermal runaway test method can calculate the gas production rate u during battery thermal runaway more accurately by collecting the air pressure value in the box body. At the same time, during the test, the pressure relief valve is used to connect the inner cavity of the box body with the outside world. When the battery undergoes thermal runaway, the gas produced will leak to the outside through the pressure relief valve, which can effectively relieve the excessive air pressure in the box body, thereby avoiding additional temperature rise, and then maintaining the temperature in the box body within a predictable range, which can avoid the influence of high temperature on the test results, and further ensure that the gas production rate during battery thermal runaway has a high accuracy. In the application of the test method provided in the embodiments of the present application, after mastering the relatively accurate gas production rate u during battery thermal runaway, it is beneficial to reasonably select the number and specifications of the explosion-proof valves of the battery pack, ensure safe pressure relief when the battery undergoes thermal runaway, and ultimately ensure the safety of the battery system

[0043] Refer to Figure 5 Based on the above battery thermal runaway test equipment, the embodiments of the present application also provide a battery thermal runaway test method. The battery thermal runaway test method is applied to the battery thermal runaway test equipment. The battery thermal runaway test equipment includes a box body and a pressure relief valve arranged on the box body. The pressure relief valve is used to connect the inner cavity of the box body with the outside world; specifically in this embodiment, the method may include the following steps S2010-S2090

[0044] Step S2010: Obtain the initial air pressure value in the box body

[0045] After the battery under test is placed in the box, before the controller controls the charging circuit to charge the battery under test until it undergoes thermal runaway, the controller controls the pressure sensor to collect the air pressure value inside the box. At this time, the air pressure value inside the box is the initial air pressure value P 0 In this embodiment, the execution of step S2010 can be obtained before or during the charging of the battery under test.

[0046] Step S2030: Charge the battery.

[0047] Place the battery under test in the box. In some embodiments, the controller controls the charging circuit to charge the battery under test until it undergoes thermal runaway; in other embodiments, the controller can also control the heating element (such as an electric heating plate, heating sheet, etc.) to heat the battery under test to make it undergo thermal runaway.

[0048] In some examples, before step S2030, it further includes: estimating the gas production rate u when the battery under test is in a thermally runaway state and determining the number of pressure relief valves. When setting up the battery thermal runaway test equipment, the gas production rate of the battery can be pre-calculated, and the specifications and number of pressure relief valves corresponding to this gas production rate can be selected so that the number of pressure relief valves matches the estimated gas production rate in the thermally runaway state of the battery under test, thereby reducing the possibility of accidents due to untimely pressure relief during the test and avoiding accuracy problems caused by the gas production rate of the battery being significantly greater than the exhaust rate of the pressure relief valve, thus improving the accuracy of the test results. Further, the estimation of the gas production rate u when the battery under test is in a thermally runaway state can be based on empirical values or can be calculated based on the model / specific component characteristics / capacity of the battery.

[0049] Step S2050: When the battery placed in the box of the battery thermal runaway test equipment undergoes thermal runaway, obtain the air pressure inside the box as the runaway air pressure value.

[0050] Step S2050 can refer to the description of step S1030 above and will not be elaborated here.

[0051] Step S2070: Determine the exhaust rate of the pressure relief valve provided on the box and communicating the inner cavity of the box with the outside according to the runaway air pressure value.

[0052] In some embodiments, the controller can directly determine according to the runaway air pressure value P 1 and the exhaust rate V 1 of the pressure relief valve the relationship between them, and determine the exhaust rate V 1 at this runaway air pressure value P 1 . Specifically, the controller can pre-store the corresponding relationship between the air pressure and the exhaust rate of the pressure relief valve (such as a mapping table or a relationship curve, etc.). When the runaway air pressure value P 1After that, the corresponding exhaust rate V can be directly queried by looking up a table. 1 .

[0053] In some other embodiments, the exhaust rate V of the pressure relief valve 1 is determined based on the relative air pressure value P Δ , where the relative air pressure value P Δ refers to the increased air pressure value relative to the initial air pressure value P 1 under the condition of battery thermal runaway. After the controller obtains the runaway air pressure value P 1 , according to the initial air pressure value P 0 and the runaway air pressure value P 1 , it calculates the relative air pressure value P Δ , that is, the difference between the runaway air pressure value P 1 and the initial air pressure value P 0 . Expressed by a calculation formula, it is:

[0054] P Δ = P 1 - P 0

[0055] And further, according to the preset mapping relationship f(P) between air pressure and exhaust rate, it determines the exhaust rate V of the pressure relief valve corresponding to this relative air pressure value P Δ . The exhaust rate V of the pressure relief valve 1 can be expressed as: 1

[0056] V 1 = f(P)

[0057] Figure 4 Please refer to Figure 4 , in another embodiment, "the exhaust rate of the pressure relief valve can be determined through the following steps": During the process of the battery in the box being in a thermal runaway state, the controller controls the air pressure sensor to obtain the runaway air pressure value P 1 during the thermal runaway period of the battery, and draws the runaway air pressure curve during this period (see Figure 6 ); According to the runaway air pressure curve and the initial air pressure value P 0 , it calculates and draws the relative air pressure curve, and the relative air pressure curve is the difference curve between the air pressure value in the runaway air pressure curve and the initial air pressure value P 0 ; According to the relative air pressure curve and the preset relationship curve between air pressure and exhaust rate, it obtains the exhaust rate curve of the pressure relief valve corresponding to the relative air pressure value P Δ ; Among them, the relationship curve represents the corresponding relationship between the exhaust rate of the pressure relief valve and the air pressure. By using the exhaust rate curve of the pressure relief valve corresponding to the relative air pressure value P Δ to obtain the exhaust rate of the pressure relief valve to adapt to the dynamically changing air pressure environment in the box, the accuracy of the detection data and results is improved.

[0058] Step S2090: Determine the gas generation rate during battery thermal runaway according to the exhaust rate.

[0059] In some embodiments, when the number of pressure relief valves is one, the gas generation rate u during battery thermal runaway is equal to the exhaust rate V 1 Equal.

[0060] In other embodiments, the number of pressure relief valves can be greater than one. The gas generation rate u during battery thermal runaway is equal to the total exhaust rate V of multiple pressure relief valves 2 Equal. If the number of pressure relief valves is N, then according to the runaway air pressure value P 1 , it is necessary to determine the exhaust rate V of N pressure relief valves 1 . According to the exhaust rate V of N pressure relief valves 1 Calculate the total exhaust rate V 2 , the total exhaust rate V 2 Namely:

[0061] V 2 = N × V 1

[0062] Then, according to the total exhaust rate V 2 Determine the gas generation rate u during battery thermal runaway. The gas generation rate u is:

[0063] u = N × f(P)

[0064] In this embodiment, by obtaining the initial air pressure value P 0 and the runaway air pressure value P1 in the box, calculate the relative air pressure value P Δ , according to the relative air pressure value P Δ Determine the exhaust rate V of the pressure relief valve 1 , thereby determining the gas generation rate u of battery thermal runaway. During the test, the determination of the gas generation rate u of battery thermal runaway in the case of multiple pressure relief valves is also included, further improving the accuracy of the test results. At the same time, during the test, the pressure relief valve is used to connect the inner cavity of the box with the outside world. When the battery undergoes thermal runaway, the gas generated by it will leak to the outside through the pressure relief valve, which can effectively relieve the excessive air pressure in the box. When setting up the battery thermal runaway test equipment, calculate the gas generation rate of the battery in advance, select the specifications and quantity of the pressure relief valve corresponding to this gas generation rate, and make the quantity of the pressure relief valve match the estimated gas generation rate under the thermal runaway state of the battery to be tested, so as to reduce the possibility of accidents caused by untimely pressure relief during the test. In the application of the test method provided in the embodiments of the present application, after mastering the relatively accurate gas generation rate u of battery thermal runaway, it is beneficial to reasonably select the quantity and specifications of the explosion-proof valves of the battery pack, ensure safe pressure relief when the battery undergoes thermal runaway, and ultimately ensure the safety of the battery system.

[0065] Please refer to Figure 7 Based on the above battery thermal runaway test device 100, the present application further provides a battery thermal runaway test device 300. The battery thermal runaway test device 300 is applied to the battery thermal runaway test device 100 and is used to determine the gas production rate during battery thermal runaway.

[0066] The battery thermal runaway test device 300 includes a pressure acquisition module 310, an exhaust rate determination module 320, and a gas production rate determination module 330. The pressure acquisition module 310 is used to obtain the runaway air pressure value P in the box when the battery placed in the box is in thermal runaway. 1 ; The exhaust rate determination module 320 is used to determine the exhaust rate V of the pressure relief valve according to the runaway air pressure value P 1 ; The gas production rate determination module 330 is used to determine the gas production rate u during battery thermal runaway according to the exhaust rate V 1 ; 1 In some embodiments, the pressure acquisition module 310 is further used to calculate the relative air pressure value P according to the runaway air pressure value P

[0067] and the initial air pressure value P 1 ; The relative air pressure value P 0 is the difference between the runaway air pressure value P Δ and the initial air pressure value P Δ . 1 and the initial air pressure value P 0 .

[0068] In some embodiments, the exhaust rate determination module 320 is further used to determine the total exhaust rate V of a plurality of pressure relief valves 50 according to the preset mapping relationship between air pressure and exhaust rate 2 ; According to the relative air pressure curve and the preset relationship curve between air pressure and exhaust rate, obtain the exhaust rate curve of the pressure relief valve 50 corresponding to the relative air pressure value P Δ .

[0069] In some embodiments, when there are multiple pressure relief valves 50, the gas production rate determination module 330 is further used to determine the gas production rate u during battery thermal runaway according to the total exhaust rate V 2 .

[0070] Please refer to Figure 8 Based on the above battery thermal runaway test method, the present application further provides a computer-readable storage medium 400. The computer-readable storage medium 400 stores program code 410 executable by a processor. The program code 410 can be called by a controller 70 to execute the method described in the embodiments of the above battery thermal runaway test method.

[0071] A computer-readable storage medium may be an electronic memory such as a flash memory, an EEPROM (Electrically Erasable Programmable Read-Only Memory), an EPROM, a hard disk, or a ROM. Optionally, the computer-readable storage medium includes a non-transitory computer-readable storage medium. The computer-readable storage medium 400 has a storage space for program codes that execute any method steps in the above-described methods. These program codes may be read from or written to one or more computer program products. The program codes may be compressed in a suitable form, for example.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for testing thermal runaway of a battery, characterized in that, applied to a battery thermal runaway test device, the battery thermal runaway test device includes a box body and a pressure relief valve, the box body defines a closed space, the pressure relief valve is connected to the box body, and the pressure relief valve communicates with the inside and outside of the box body when it is opened; the method includes: When the battery placed in the box body undergoes thermal runaway, obtaining the air pressure in the box body as the runaway air pressure value; Determining the exhaust rate of the pressure relief valve according to the runaway air pressure value; When the number of the pressure relief valves is greater than one, the step of determining the exhaust rate of the pressure relief valve includes: determining the exhaust rates of multiple pressure relief valves according to the runaway air pressure value respectively; Determining the gas production rate during thermal runaway of the battery according to the exhaust rate; The determining the gas production rate during thermal runaway of the battery according to the exhaust rate includes: calculating the total exhaust rate according to the exhaust rates of multiple pressure relief valves; determining the total exhaust rate as the gas production rate during thermal runaway of the battery.

2. The battery thermal runaway test method according to claim 1, characterized in that, Before obtaining the air pressure in the box body as the runaway air pressure value, the method further includes: Obtaining the initial air pressure value in the box body; Charging the battery.

3. The battery thermal runaway test method according to claim 2, characterized in that, The step of determining the exhaust rate of the pressure relief valve includes: Obtaining a relative air pressure value by calculating the difference between the runaway air pressure value and the initial air pressure value; Determining the exhaust rate of the pressure relief valve based on the relative air pressure value.

4. The battery thermal runaway test method according to claim 3, characterized in that, The determining the exhaust rate of the pressure relief valve based on the relative air pressure value includes: determining the exhaust rate of the pressure relief valve via the mapping relationship between air pressure and exhaust rate.

5. The battery thermal runaway test method according to claim 2, characterized in that, The step of determining the exhaust rate of the pressure relief valve includes: Determining a runaway air pressure curve according to the change state of the runaway air pressure value over time; Calculating a difference curve between the air pressure value in the runaway air pressure curve and the initial air pressure value to obtain a relative air pressure curve; Obtaining the exhaust rate curve of the pressure relief valve according to the relative air pressure curve and the relationship curve between air pressure and exhaust rate.

6. A battery thermal runaway test device, characterized in that, including: A box body; A pressure sensor, the detection end of the pressure sensor is located inside the box body; A pressure relief valve, connected to the box body; The pressure relief valve can discharge the gas in the box body to the outside; And A controller, electrically connected to the pressure sensor, the controller can obtain the air pressure in the box body as the runaway air pressure value when the battery placed in the box body undergoes thermal runaway; Determining the exhaust rate of the pressure relief valve according to the runaway air pressure value; Determining the gas production rate during thermal runaway of the battery according to the exhaust rate.

7. The battery thermal runaway test device according to claim 6, characterized in that, The battery thermal runaway test device further includes a placeholder, and the placeholder is arranged in the box body to adjust the difference between the effective volume of the box body and the effective volume of the battery box for applying the battery.

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