A thermal test method and fixture for thermal runaway of battery cells

Abstract

The present invention discloses a thermal testing method and fixture for thermal runaway of a battery cell. The thermal testing method comprises placing a target battery cell and a reference battery cell between two side walls of the fixture, with the target battery cell and the reference battery cell spaced apart, wherein the reference battery cell is an inactivated battery cell; triggering the target battery cell to cause thermal runaway; and deriving the energy conducted by the target battery cell during thermal runaway based on the temperature difference between the reference battery cell before and after the target battery cell experiences thermal runaway and the temperature difference between the two side walls of the fixture before and after the target battery cell experiences thermal runaway. The thermal testing method for thermal runaway of a battery cell can quantitatively test the amount of heat transferred during thermal runaway, thereby facilitating the selection of appropriate thermal insulation materials for protection during battery design.

Description

Technical Field

[0001] The present invention relates to the technical field of battery testing, and in particular to a heat testing method and a fixture for thermal runaway of a battery cell. Background Art

[0002] The current existing battery cell thermal runaway test directly verifies whether heat diffusion occurs, determines whether the heat generated during thermal runaway is transferred to adjacent cells, and observes whether thermal runaway occurs in adjacent cells. This test method can only make a qualitative judgment, but cannot quantitatively test the specific amount of heat transferred, and thus cannot accurately verify the thermal insulation performance of the thermal insulation material. Only by determining the amount of heat transferred to adjacent cells after the battery cell runs away can we more accurately select thermal insulation materials and provide a design reference for thermal protection. Summary of the Invention

[0003] The first purpose of the present invention is to propose a thermal testing method for thermal runaway of a battery cell, which can quantitatively test the heat transferred when the battery cell undergoes thermal runaway, thereby facilitating the selection of appropriate thermal insulation materials for protection during battery design.

[0004] The second object of the present invention is to provide a thermal test fixture for thermal runaway of a battery cell, which can be used to more conveniently perform thermal runaway experiments.

[0005] In order to achieve the above technical effects, the technical solutions of the present invention are as follows:

[0006] The present invention discloses a thermal testing method for thermal runaway of a battery cell, comprising: placing a target battery cell and a reference battery cell between two side walls of a fixture, and distributing the target battery cell and the reference battery cell at intervals, wherein the reference battery cell is an unactivated battery cell; triggering the target battery cell to cause thermal runaway; and deriving the energy conducted when the target battery cell experiences thermal runaway based on the temperature difference between the reference battery cell before and after the thermal runaway occurs in the target battery cell and the temperature difference between the two side walls of the fixture before and after the thermal runaway occurs in the target battery cell.

[0007] In some embodiments, the energy conducted when thermal runaway occurs in the target cell is obtained based on the temperature difference between the reference cell and the temperature difference between the two side walls of the fixture, including: Q 传 =Q 参照电芯 +Q 夹具 =C 目标电芯 *M 参照电芯 *ΔT 参照电芯 +C 夹具 *M 夹具 *ΔT 夹具 ; Among them: C 目标电芯 is the specific heat capacity of the target cell, M 参照电芯 is the mass of the reference cell, ΔT参照电芯 is the temperature difference of the reference cell before and after the target cell experiences thermal runaway; C 夹具 is the specific heat capacity of the fixture, M 夹具 is the mass of the fixture, ΔT 夹具 is the temperature difference of the fixture before and after thermal runaway occurs in the target battery cell.

[0008] In some specific embodiments, the C 目标电芯 The acquisition steps are: packing a plurality of the target battery cells and placing them in an accelerating calorimeter, and spaced apart from the side wall of the insulating cavity of the accelerating calorimeter; and calculating the specific heat capacity of the target battery cell according to the temperature change of the heating device of the accelerating calorimeter and the temperature change of the target battery cell.

[0009] In some embodiments, the step of placing the target battery cell and the reference battery cell between two side walls of a fixture and distributing the target battery cell and the reference battery cell at intervals further includes: providing a thermal insulation layer between the target battery cell and the reference battery cell.

[0010] In some embodiments, the step of placing the target battery cell and the reference battery cell between two side walls of the fixture and distributing the target battery cell and the reference battery cell at intervals further includes: connecting the target battery cell and the reference battery cell in series or in parallel.

[0011] In some embodiments, triggering the target battery cell to cause thermal runaway includes: triggering the target battery cell to cause thermal runaway by acupuncture or heating.

[0012] The present invention also discloses a thermal test fixture for thermal runaway of a battery cell, comprising: a clamping plate, wherein the clamping plates are arranged at intervals, and a thermal insulation layer is provided on the side of the two clamping plates facing each other; a fixed module, wherein the two ends of the fixed module are respectively connected to the two clamping plates, and the fixed module is used to support the target battery cell and the reference battery cell.

[0013] In some embodiments, the fixing module includes a supporting component and a limiting component arranged at intervals along the height direction of the clamping plate, the supporting component contacts the bottom walls of the target battery cell and the reference battery cell to support the target battery cell and the reference battery cell, and the limiting component contacts the surrounding walls of the target battery cell and the reference battery cell to clamp the target battery cell and the reference battery cell.

[0014] In some embodiments, the support assembly includes multiple support columns and fixing nuts, and the multiple support columns are used to support the target battery cells. The two ends of each support column are respectively passed through the two clamps, and the fixing nuts are connected to the support columns to lock the support columns on the clamps.

[0015] In some embodiments, the limiting assembly includes two limiting columns and limiting nuts, the two ends of each limiting column are respectively passed through the two clamps, and the limiting nuts are connected to the limiting columns to lock the limiting columns on the clamps; wherein: the target battery cell and the reference battery cell are arranged between the two limiting columns.

[0016] The beneficial effects of the heat testing method for thermal runaway of battery cells of the present invention are as follows: since the reference battery cell is an unactivated battery cell, the temperature of the unactivated reference battery cell reaches the characteristic temperature of battery cell runaway, and thermal runaway will still not occur, and will not affect the heat transfer test, thereby achieving the purpose of accurately measuring the heat conducted by the thermal runaway of the target battery cell, which is conducive to selecting suitable thermal insulation materials for protection during battery design.

[0017] The beneficial effects of the thermal test fixture for thermal runaway of a battery cell of the present invention are as follows: since the fixture only includes two clamping plates and a fixing module, compared with existing thermal runaway test fixtures, the structure is very simple and easy to operate.

[0018] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a flow chart of a thermal test method for thermal runaway of a battery cell according to a first embodiment of the present invention;

[0020] Figure 2 Schematic diagram of a test using the thermal test fixture for thermal runaway of a battery cell according to the first embodiment of the present invention;

[0021] Figure 3 This is a flow chart of a thermal test method for thermal runaway of a battery cell according to a second embodiment of the present invention;

[0022] Figure 4 Schematic diagram of a test using the thermal test fixture for thermal runaway of a battery cell according to the second embodiment of the present invention;

[0023] Figure 5 This is a flow chart of a thermal test method for thermal runaway of a battery cell according to a third embodiment of the present invention;

[0024] Figure 6 Schematic diagram of testing using the thermal test fixture for thermal runaway of a battery cell according to the third embodiment of the present invention.

[0025] Reference numerals:

[0026] 1. Splint;

[0027] 2. Fixed module; 21. Support assembly; 211. Support column; 212. Fixed nut; 22. Limit assembly; 221. Limit column; 222. Limit nut;

[0028] 3. Thermal insulation layer;

[0029] 4. Target cell; 5. Reference cell. DETAILED DESCRIPTION

[0030] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved more clear, the technical solutions of the present invention are further described below with reference to the accompanying drawings and through specific implementation methods.

[0031] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0032] In addition, features defined as "first" or "second" may explicitly or implicitly include one or more of the features, and are used to distinguish and describe features, without distinction of order or importance. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0033] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0034] Example 1:

[0035] Refer to the following Figure 1-Figure 2 The specific process of the thermal test method for thermal runaway of a battery cell according to an embodiment of the present invention is described.

[0036] like Figure 2As shown, the thermal test fixture for thermal runaway of a battery cell of this embodiment comprises: a clamping plate 1 and a fixed module 2. The clamping plates 1 are two spaced apart, and a thermal insulation layer 3 is provided on the sides of the two clamping plates 1 facing each other. It should be noted that during the experiment, in order to test the impact of the thermal runaway of the target battery cell 4 on the reference battery cell 5 as accurately as possible, the heat generated by the thermal runaway of the target battery cell 4 is transferred to the reference battery cell 5 as much as possible during the heat conduction process. Therefore, a thermal insulation layer 3 is provided on the clamping plate 1.

[0037] like Figure 2 As shown, the two ends of the fixed module 2 are respectively connected to the two clamps 1, and the fixed module 2 is used to support the target battery cell 4 and the reference battery cell 5. The fixed module 2 includes a support component 21 and a limit component 22 arranged at intervals along the height direction of the clamp 1. It can be understood that the use of the support component 21 and the limit component 22 to fix the target battery cell 4 and the reference battery cell 5 not only facilitates the connection between the two and the fixture, but also ensures the stability of the connection between the fixture and the target battery cell 4 and the reference battery cell 5, ensuring stable testing.

[0038] like Figure 2 As shown, the support assembly 21 includes a plurality of support columns 211 and fixing nuts 212. The plurality of support columns 211 are used to support the target battery cell 4. The two ends of each support column 211 are respectively passed through the two clamps 1. The fixing nuts 212 are connected to the support columns 211 to lock the support columns 211 on the clamps 1. As a result, the support columns 211 can not only stably support the target battery cell 4 and the reference battery cell 5, but also reduce the contact area with the target battery cell 4 and the reference battery cell 5, thereby reducing the heat transfer between the support assembly 21 and the target battery cell 4 and the reference battery cell 5, and improving the test accuracy. At the same time, the connection structure of the support column 211 is locked by the fixing nut 212. During the actual working process, the spacing between the two clamps 1 can be adjusted according to actual needs, so that the fixture of this embodiment can be applicable to target battery cells 4 and reference battery cells 5 of various sizes.

[0039] like Figure 2As shown, the limiting assembly 22 includes two limiting posts 221 and limiting nuts 222. The two ends of each limiting post 221 are respectively passed through the two clamps 1, and the limiting nuts 222 are connected to the limiting posts 221 to lock the limiting posts 221 on the clamps 1: the target battery cell 4 and the reference battery cell 5 are arranged between the two limiting posts 221. As a result, the limiting posts 221 can not only stably limit the target battery cell 4 and the reference battery cell 5, but also reduce the contact area with the target battery cell 4 and the reference battery cell 5, thereby reducing the heat transfer between the limiting assembly 22 and the target battery cell 4 and the reference battery cell 5, and improving the test accuracy. At the same time, the connection structure of the limiting posts 221 is locked by the limiting nuts 222. During actual work, the distance between the two clamps 1 can be adjusted according to actual needs, so that the fixture of this embodiment can be applied to target batteries 4 and reference batteries 5 of various sizes.

[0040] like Figure 1 As shown, the thermal test method for thermal runaway of a battery cell in this embodiment includes:

[0041] S1: Place the target cell 4 and the reference cell 5 between the two side walls of the fixture, and space the target cell 4 and the reference cell 5 apart. The reference cell 5 is an inactivated cell.

[0042] Specifically, during the actual placement process, the limiting nut 222 and the fixing nut 212 are first used to lock one end of the limiting column 221 and the support column 211 on a clamping plate 1, and then the target battery cell 4 and the reference battery cell 5 are placed on the support column 211, and the two limiting columns 221 clamp the target battery cell 4 and the reference battery cell 5, and then another clamping plate 1 is inserted into the limiting column 221 and the other end of the support column 211, and the spacing is adjusted so that the distance between the target battery cell 4 and one clamping plate 1 is equal to the distance between the reference battery cell 5 and the other clamping plate 1, and then the limiting nut 222 and the fixing nut 212 are used to lock the other end of the limiting column 221 and the support column 211 on the other clamping plate 1.

[0043] S2: triggering the target battery cell 4 to cause thermal runaway;

[0044] Specifically, the target cell 4 can be triggered to experience thermal runaway by pricking or heating. When heating is used to trigger the target cell 4 to heat, the heating sheet should be attached to the side of the target cell 4 facing away from the reference cell 5 and the clamping plate 1 to reduce the impact of the heating sheet on the clamping plate 1 and the reference cell 5. Of course, other methods such as powering on the target cell 4 can also be used to trigger thermal runaway, not limited to pricking or heating.

[0045] S3: deriving the conducted energy of the target battery cell 4 when thermal runaway occurs based on the temperature difference of the reference battery cell 5 before and after the target battery cell 4 experiences thermal runaway and the temperature difference of the two side walls of the fixture before and after the target battery cell 4 experiences thermal runaway.

[0046] Specifically, the energy Q conducted when the target cell 4 experiences thermal runaway is 传 The calculation formula is as follows:

[0047] Q 传 =Q 参照电芯 +Q 夹具 =C 目标电芯 *M 参照电芯 *ΔT 参照电芯 +C 夹具 *M 夹具 *ΔT 夹具 ;

[0048] Where: C 目标电芯 is the specific heat capacity of the target battery cell 4, M 参照电芯 is the mass of reference cell 5, ΔT 参照电芯 C is the temperature difference between the reference cell 5 and the target cell 4 before and after thermal runaway occurs; 夹具 is the specific heat capacity of the fixture, M 夹具 is the mass of the fixture, ΔT 夹具 is the temperature difference of the fixture before and after the thermal runaway of the target battery cell 4. It should be further explained that since the support column 211, the limiting column 221, the fixing nut 212 and the limiting nut 222 have a relatively small impact on the experimental results, C 夹具 *M 夹具 *ΔT 夹具 =2*C 夹板 *M 夹板 *ΔT 夹板 .

[0049] It can be understood that since the reference cell 5 uses an unactivated cell, that is, the reference cell 5 has no energy, even if the heat from the thermal runaway of the target cell 4 is transferred to the reference cell 5, and the temperature of the unactivated reference cell 5 reaches the characteristic temperature of the cell runaway, thermal runaway will not occur, and will not affect the heat transfer test. In this way, the heat conducted by the target cell 4 due to thermal runaway when there is no insulation material between the target cell 4 and the reference cell 5 can be accurately measured, thereby providing a numerical reference when designing insulation materials.

[0050] Furthermore, C 目标电芯 The steps of obtaining the C value are as follows: pack multiple target cells 4 and place them in an accelerating calorimeter, and space them from the side wall of the thermal insulation chamber of the accelerating calorimeter; calculate the specific heat capacity of the target cell 4 according to the temperature change of the heating device of the accelerating calorimeter and the temperature change of the target cell 4. 目标电芯 The test makes the thermal test method for thermal runaway of the battery cell of this embodiment applicable to the test of more non-standard target battery cells 4.

[0051] Example 2:

[0052] Refer to the following Figure 3-Figure 4 The specific process of the thermal test method for thermal runaway of a battery cell according to an embodiment of the present invention is described.

[0053] Q1: Place the target cell 4 and the reference cell 5 between the two side walls of the fixture, and space the target cell 4 and the reference cell 5 apart. Set a thermal insulation layer 3 between the target cell 4 and the reference cell 5. The reference cell 5 is an unactivated cell.

[0054] Specifically, during the actual placement process, the limiting nut 222 and the fixing nut 212 are first used to lock one end of the limiting column 221 and the support column 211 on a clamping plate 1, and then the target battery cell 4 and the reference battery cell 5 are placed on the support column 211, and the two limiting columns 221 clamp the target battery cell 4 and the reference battery cell 5, and then another clamping plate 1 is inserted into the limiting column 221 and the other end of the support column 211, and the spacing is adjusted so that the distance between the target battery cell 4 and one clamping plate 1 is equal to the distance between the reference battery cell 5 and the other clamping plate 1, and then the limiting nut 222 and the fixing nut 212 are used to lock the other end of the limiting column 221 and the support column 211 on the other clamping plate 1.

[0055] Q2: Trigger the target battery cell 4 to cause thermal runaway;

[0056] Specifically, the target cell 4 can be triggered to experience thermal runaway by pricking or heating. When heating is used to trigger the target cell 4 to heat, the heating sheet should be attached to the side of the target cell 4 facing away from the reference cell 5 and the clamping plate 1 to reduce the impact of the heating sheet on the clamping plate 1 and the reference cell 5. Of course, other methods such as powering on the target cell 4 can also be used to trigger thermal runaway, not limited to pricking or heating.

[0057] Q3: The energy conducted when the target cell 4 experiences thermal runaway is obtained based on the temperature difference of the reference cell 5 before and after the target cell 4 experiences thermal runaway and the temperature difference of the two side walls of the fixture before and after the target cell 4 experiences thermal runaway.

[0058] Specifically, the energy Q conducted when the target cell 4 experiences thermal runaway is 传 The calculation formula is as follows:

[0059] Q 传 =Q 参照电芯 +Q 夹具 =C 目标电芯 *M 参照电芯 *ΔT 参照电芯 +C 夹具 *M 夹具 *ΔT 夹具 ;;

[0060] Where: C 目标电芯 is the specific heat capacity of the target battery cell 4, M 参照电芯 is the mass of reference cell 5, ΔT 参照电芯 C is the temperature difference between the reference cell 5 and the target cell 4 before and after thermal runaway occurs; 夹具 is the specific heat capacity of the fixture, M 夹具 is the mass of the fixture, ΔT 夹具 is the temperature difference of the fixture before and after the thermal runaway of the target battery cell 4. It should be further explained that since the support column 211, the limiting column 221, the fixing nut 212 and the limiting nut 222 have a relatively small impact on the experimental results, C 夹具 *M 夹具 *ΔT 夹具 =2*C 夹板 *M 夹板 *ΔT 夹板 .

[0061] It can be understood that since the reference cell 5 uses an unactivated cell, that is, the reference cell 5 has no energy, even if the heat from the thermal runaway of the target cell 4 is transferred to the reference cell 5, and the temperature of the unactivated reference cell 5 reaches the characteristic temperature of the cell runaway, thermal runaway will still not occur, and will not affect the heat transfer test. In this way, when the insulation layer 3 is set between the target cell 4 and the reference cell 5, the heat conducted out of the thermal runaway of the target cell 4 can be accurately measured. In this way, the insulation capacity of the insulation layer 3 can be tested, thereby facilitating the selection of the insulation layer 3 in battery design.

[0062] Example 3:

[0063] Refer to the following Figure 5-Figure 6 The specific process of the thermal test method for thermal runaway of a battery cell according to an embodiment of the present invention is described.

[0064] W1: Place the target cell 4 and the reference cell 5 between the two side walls of the fixture, and space the target cell 4 and the reference cell 5 apart. Connect the target cell 4 and the reference cell 5 in series or in parallel. The reference cell 5 is an inactivated cell.

[0065] Specifically, during the actual placement process, the limiting nut 222 and the fixing nut 212 are first used to lock one end of the limiting column 221 and the support column 211 on a clamping plate 1, and then the target battery cell 4 and the reference battery cell 5 are placed on the support column 211, and the two limiting columns 221 clamp the target battery cell 4 and the reference battery cell 5, and then another clamping plate 1 is inserted into the limiting column 221 and the other end of the support column 211, and the spacing is adjusted so that the distance between the target battery cell 4 and one clamping plate 1 is equal to the distance between the reference battery cell 5 and the other clamping plate 1, and then the limiting nut 222 and the fixing nut 212 are used to lock the other end of the limiting column 221 and the support column 211 on the other clamping plate 1.

[0066] W2: trigger the target cell 4 to cause thermal runaway;

[0067] Specifically, the target cell 4 can be triggered to experience thermal runaway by pricking or heating. When heating is used to trigger the target cell 4 to heat, the heating sheet should be attached to the side of the target cell 4 facing away from the reference cell 5 and the clamping plate 1 to reduce the impact of the heating sheet on the clamping plate 1 and the reference cell 5. Of course, other methods such as powering on the target cell 4 can also be used to trigger thermal runaway, not limited to pricking or heating.

[0068] W3: The conducted energy of the target cell 4 when thermal runaway occurs is obtained based on the temperature difference of the reference cell 5 before and after the target cell 4 experiences thermal runaway and the temperature difference of the two side walls of the fixture before and after the target cell 4 experiences thermal runaway.

[0069] Specifically, the energy Q conducted when the target cell 4 experiences thermal runaway is 传 The calculation formula is as follows:

[0070] Q 传 =Q 参照电芯 +Q 夹具 =C 目标电芯 *M 参照电芯 *ΔT 参照电芯 +C 夹具 *M 夹具 *ΔT 夹具 ;;

[0071] Where: C 目标电芯 is the specific heat capacity of the target battery cell 4, M 参照电芯 is the mass of reference cell 5, ΔT 参照电芯 C is the temperature difference between the reference cell 5 and the target cell 4 before and after thermal runaway occurs; 夹具 is the specific heat capacity of the fixture, M 夹具 is the mass of the fixture, ΔT 夹具 is the temperature difference of the fixture before and after the thermal runaway of the target battery cell 4. It should be further explained that since the support column 211, the limiting column 221, the fixing nut 212 and the limiting nut 222 have a relatively small impact on the experimental results, C 夹具 *M 夹具 *ΔT 夹具 =2*C 夹板 *M 夹板 *ΔT 夹板 .

[0072] It can be understood that since the reference cell 5 uses an unactivated cell, that is, the reference cell 5 has no energy, even if the heat of thermal runaway of the target cell 4 is transferred to the reference cell 5, and the temperature of the unactivated reference cell 5 reaches the characteristic temperature of cell runaway, thermal runaway will still not occur, and will not affect the heat transfer test. In this way, the heat conducted by the target cell 4 due to thermal runaway can be accurately measured when there is no insulation layer 3 between the target cell 4 and the reference cell 5, but there is an electrical connection between the target cell 4 and the reference cell 5, thereby providing a numerical reference when designing insulation materials.

[0073] Throughout this specification, references to "some embodiments," "other embodiments," and the like indicate that the specific features, structures, materials, or characteristics described in connection with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0074] The above contents are only preferred embodiments of the present invention. For ordinary technicians in this field, according to the concept of the present invention, there may be changes in the specific implementation methods and application scopes. The contents of this specification should not be understood as limiting the present invention.

Claims

1. A thermal test method for thermal runaway of a battery cell, characterized in that: include: Placing a target cell and a reference cell between two side walls of a fixture so that the target cell and the reference cell are spaced apart, wherein the reference cell is an unactivated cell; triggering the target battery cell to cause thermal runaway; Determining the energy conducted when the target battery cell experiences thermal runaway based on the temperature difference between the reference battery cell before and after the target battery cell experiences thermal runaway and the temperature difference between the two side walls of the fixture before and after the target battery cell experiences thermal runaway; The energy conducted when thermal runaway occurs in the target battery cell is obtained based on the temperature difference of the reference battery cell and the temperature difference of the two side walls of the fixture, including: Q 传 = Q 参照电芯 + Q 夹具 = C 目标电芯 * M 参照电芯 * ΔT 参照电芯 + C 夹具 * M 夹具 * ΔT 夹具 ; Where: C 目标电芯 is the specific heat capacity of the target cell, M 参照电芯 is the mass of the reference cell, △T 参照电芯 is the temperature difference of the reference cell before and after the target cell experiences thermal runaway; C 夹具 is the specific heat capacity of the fixture, M 夹具 is the mass of the fixture, △T 夹具 is the temperature difference of the fixture before and after thermal runaway occurs in the target battery cell.

2. The thermal test method for thermal runaway of a battery cell according to claim 1, characterized in that: The C 目标电芯 The steps to obtain are: Packing a plurality of the target battery cells and placing them in an accelerating calorimeter, and spacing them from the side wall of the insulating cavity of the accelerating calorimeter; The specific heat capacity of the target battery cell is calculated according to the temperature change of the heating device of the accelerating calorimeter and the temperature change of the target battery cell.

3. The thermal test method for thermal runaway of a battery cell according to claim 1, characterized in that: The step of placing the target battery cell and the reference battery cell between two side walls of the fixture, and making the target battery cell and the reference battery cell spaced apart from each other, further comprises: A thermal insulation layer is provided between the target battery cell and the reference battery cell.

4. The thermal test method for thermal runaway of a battery cell according to claim 1, characterized in that: The step of placing the target battery cell and the reference battery cell between two side walls of the fixture, and making the target battery cell and the reference battery cell spaced apart from each other, further comprises: The target battery cell and the reference battery cell are connected in series or in parallel.

5. The thermal test method for thermal runaway of a battery cell according to claim 1, characterized in that: Triggering the target battery cell to cause thermal runaway includes: triggering the target battery cell to cause thermal runaway by acupuncture or heating.

6. A thermal test fixture for thermal runaway of a battery cell, characterized in that: The thermal test method for thermal runaway of a battery cell according to any one of claims 1 to 5, wherein the thermal test fixture for thermal runaway of a battery cell comprises: Two splints are spaced apart; A fixed module, both ends of which are connected to the two clamping plates, and the fixed module is used to support the target battery cell and the reference battery cell; A heat insulation layer is provided on the sides of the two clamping plates facing each other.

7. The thermal test fixture for thermal runaway of a battery cell according to claim 6, characterized in that: The fixing module includes a supporting component and a limiting component arranged at intervals along the height direction of the clamping plate, the supporting component contacts the bottom walls of the target battery cell and the reference battery cell to support the target battery cell and the reference battery cell, and the limiting component contacts the peripheral walls of the target battery cell and the reference battery cell to clamp the target battery cell and the reference battery cell.

8. The thermal test fixture for thermal runaway of a battery cell according to claim 7, characterized in that: The support assembly includes a plurality of support columns and fixing nuts, wherein the plurality of support columns are used to support the target battery cell, and both ends of each support column are respectively passed through the two clamping plates, and the fixing nuts are connected to the support columns to lock the support columns on the clamping plates; and / or; The limiting assembly includes two limiting posts and limiting nuts, the two ends of each limiting post are respectively passed through the two clamping plates, and the limiting nuts are connected to the limiting posts to lock the limiting posts on the clamping plates; wherein: The target battery cell and the reference battery cell are arranged between the two limiting posts.

9. The thermal test fixture for thermal runaway of a battery cell according to claim 7, characterized in that: The heat insulation layer is located between the two clamping plates and is sandwiched between the target battery cell and the reference battery cell.

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