Battery thermal runaway test fixture and test method

Abstract

The invention discloses a battery thermal runaway test fixture and a test method. The test fixture comprises a first clamping plate, a second clamping plate, a first heat preservation pad, a second heat preservation pad and a heating plate, wherein the second clamping plate and the first clamping plate are oppositely arranged at an interval to form a test space; the first heat preservation pad is arranged in the test space and is attached to the first clamping plate; the second heat preservation pad is arranged in the test space and is attached to the second clamping plate; the heating plate is arranged in the testing space and is attached to the first heat preservation pad, and a gap used for containing the battery exists between the heating plate and the second heat preservation pad. Through the heat insulation effect of the first heat preservation pad and the second heat preservation pad, effective heat accumulation can be achieved through low-power heating, the local overheating risk caused by high power is avoided, it is ensured that thermal runaway can be stably triggered, and the heat preservation pad is particularly suitable for the characteristics that a blade battery and other thin batteries are thin in shell and small in heat capacity.

Description

Technical Field

[0001] The present application relates to the field of battery testing technology, and in particular to a battery thermal runaway test fixture and a test method. Background Art

[0002] Energy storage batteries are prone to thermal runaway under extreme operating conditions such as overcharging, overheating, or mechanical damage. This can lead to electrolyte decomposition, gas eruption, and sudden temperature increases. If the heat and gas cannot be discharged in a timely manner, the battery may catch fire or even explode, seriously affecting battery safety. Before batteries are officially put into production, standardized tests are usually conducted to simulate thermal runaway scenarios to verify the reliability of safety measures such as battery explosion-proof valves and thermal isolation designs, ensuring battery safety in thermal runaway conditions.

[0003] A common thermal runaway test involves securing the battery in a fixture and forcing thermal runaway through mechanical penetration or external heating. For example, a guide needle may be used to pierce the battery casing to simulate an internal short circuit, or a heating plate may be used to apply high temperatures to a localized area to induce electrolyte decomposition. The safety of the battery during thermal runaway is assessed by monitoring whether the explosion-proof valve opens promptly to release pressure, and whether the battery exhibits failures such as explosion or fire.

[0004] However, the above test method has certain shortcomings for thin structures such as blade batteries. Due to the thin shell and large specific surface area of thin batteries, their temperature changes significantly faster during testing than traditional batteries. Under the existing heating power, thin batteries are prone to local temperature surges, which directly trigger local electrolyte decomposition and lead to explosions. When the heating power is reduced, the heat input is insufficient. Before the temperature reaches the thermal runaway threshold, the heat input has reached equilibrium with the dissipation rate, and the battery cannot trigger thermal runaway. Therefore, it is necessary to make targeted adaptations for thin batteries based on the existing battery thermal runaway test process. Summary of the Invention

[0005] One purpose of the present application is to provide a battery thermal runaway test fixture and test method, which aims to solve the technical problem that thin batteries are difficult to perform thermal runaway tests.

[0006] To achieve the above-mentioned objectives, the present application provides a battery thermal runaway test fixture, which includes: a first clamp, a second clamp, a first insulation pad, a second insulation pad and a heating plate: the second clamp is arranged relative to the first clamp to form a test space; the first insulation pad is arranged in the test space and is in contact with the first clamp; the second insulation pad is arranged in the test space and is in contact with the second clamp; the heating plate is arranged in the test space, and the heating plate is in contact with the first insulation pad and there is a gap between the heating plate and the second insulation pad for accommodating the battery.

[0007] According to one embodiment of the present application, the test fixture further includes a temperature equalizing pad, one side surface of the temperature equalizing pad is in contact with the first insulation pad, and the other side surface of the temperature equalizing pad is coplanar with the surface of the heating plate away from the first insulation pad.

[0008] According to one embodiment of the present application, the temperature-uniform pad has the same stiffness as the heating plate; and / or the temperature-uniform pad is made of aluminum.

[0009] According to one embodiment of the present application, the first thermal insulation pad and the second thermal insulation pad are thermal insulation foams, bubbles are formed in the thermal insulation foams, the volume of the thermal insulation pad is V1, the total volume of the bubbles is V2, and V2 ≥ 20% * V1.

[0010] According to one embodiment of the present application, the thickness of the first thermal insulation pad and / or the second thermal insulation pad is L1, 0.5mm≤L1≤1.2mm.

[0011] According to one embodiment of the present application, the test fixture further includes a clamping assembly, which is used to clamp the first clamping plate and the second clamping plate to compress the test space.

[0012] According to one embodiment of the present application, a plurality of first holes are provided on the first splint, and a plurality of second holes are provided on the second splint corresponding to the first holes; the clamping assembly includes a plurality of connecting rods and a first fixing member and a second fixing member connected to both ends of the connecting rods, the connecting rods are provided with one first hole and one second hole, the first fixing member is arranged on the side of the first splint away from the second splint, and the second fixing member is arranged on the side of the second splint away from the first splint, and at least one of the first fixing member and the second fixing member is threadedly connected to the connecting rod.

[0013] According to one embodiment of the present application, the test fixture further includes a plurality of side panels, the opposite side edges of the side panels are respectively connected to the first clamping plate and the second clamping plate, and the first clamping plate, the second clamping plate and the side panels together form a test space.

[0014] According to one embodiment of the present application, the specifications of the heating plate are determined based on the size of the battery, the contact area between the battery and the heating plate is S1, the surface area of the battery facing the heating plate is S2, and 25%*S2≤S1≤40%*S.

[0015] To achieve the above objectives, the present application also provides a battery thermal runaway test method, which is based on any of the above battery thermal runaway test fixtures, and performs the test after clamping the battery to be tested using a first clamp and a second clamp.

[0016] According to one embodiment of the present application, a battery includes an explosion-proof valve provided at one end thereof; performing a test includes: driving a heating plate using a fixed power; if the explosion-proof valve opens and the battery does not explode when the battery temperature is stable, the test ends; if the explosion-proof valve does not open and the battery does not explode when the battery temperature is stable, increasing the fixed power until the explosion-proof valve opens; if the battery explodes, replacing the battery and reducing the fixed power to re-perform the test until the explosion-proof valve opens without the battery exploding.

[0017] According to one embodiment of the present application, the testing method further includes: the specifications of the heating plate are determined based on the size of the battery, the contact area between the battery and the heating plate is S1, the surface area of the battery facing the heating plate is S2, 25%*S2≤S1≤40%*S2; and / or, the fixed power is 300W; and / or, the battery to be tested is a blade battery; and / or, the heating plate is arranged at the end of the battery away from its explosion-proof valve.

[0018] The beneficial effects of this application are:

[0019] The test fixture provided in this application includes a first insulation pad and a second insulation pad. During the thermal runaway test of the battery, the first and second insulation pads clamp the battery, slowing the rate of heat dissipation from the battery surface during the thermal runaway test. This allows the heating plate to input heat at a lower power, allowing heat to accumulate continuously and gradually increase in temperature within the battery until the battery experiences the desired thermal runaway condition without causing local overheating or even explosion.

[0020] Compared with the prior art, the present application solves the technical problem that the local temperature of thin batteries rises too fast during thermal runaway tests and the heating power is difficult to adapt. In the prior art, if the heating power is too low, the thin battery has a large surface area and fast heat dissipation, and the heat input and dissipation rate are balanced, and the battery temperature is difficult to reach the temperature threshold of thermal runaway; and when the power is too high, the local temperature rise is likely to cause a violent decomposition of the electrolyte, resulting in abnormal failures such as explosions, and cannot truly reflect the design effectiveness of the explosion-proof valve. The present application uses the heat insulation effect of the first and second insulation pads to achieve effective heat accumulation through low-power heating, which not only avoids the risk of local overheating caused by high power, but also ensures that thermal runaway can be stably triggered. It is especially suitable for the characteristics of thin batteries such as blade batteries with thin shells and small heat capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0022] Figure 1 Schematic diagram of the overall structure of the test fixture provided in the embodiment of the present application;

[0023] Figure 2 is a cross-sectional schematic diagram of a test fixture provided in an embodiment of the present application;

[0024] Figure 3 It is a flow chart of the testing method provided in the embodiment of the present application.

[0025] Description of Figure Numbers:

[0026] 10. First clamping plate; 11. First hole; 20. Second clamping plate; 21. Second hole; 30. Test space; 40. First insulation pad; 50. Second insulation pad; 60. Heating plate; 70. Temperature equalizing pad; 80. Clamping assembly; 81. Connecting rod; 82. First fixing member; 83. Second fixing member; 90. Side panel. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0028] Energy storage batteries are prone to thermal runaway under extreme operating conditions such as overcharging, overheating, or mechanical damage, which can lead to fires or even explosions, seriously compromising battery safety. Preemptive testing of battery safety under thermal runaway conditions is crucial for battery production and development. Existing techniques typically use a clamp to secure the battery and force thermal runaway. The safety of the battery under thermal runaway conditions is assessed by monitoring whether the explosion-proof valve opens promptly to release pressure, and whether the battery exhibits failures such as explosions and fires.

[0029] However, the above testing method has certain shortcomings for thin structures such as blade batteries. Due to the thinner shell of thin batteries, their temperature changes faster during testing than traditional batteries. Under the current heating power, thin batteries are prone to localized temperature surges and even explosions. However, when the heating power is reduced, the heat input is insufficient, making it difficult for the battery to trigger thermal runaway.

[0030] Therefore, it is necessary to make targeted adaptations for thin batteries such as blade batteries based on the existing battery thermal runaway testing process.

[0031] See also Figure 1 and Figure 2 As shown, Figure 1Schematic diagram of the overall structure of the test fixture provided in the embodiment of the present application; Figure 2 Schematic cross-section of the test fixture provided in the embodiment of the present application.

[0032] In order to solve the above technical problems, the present application discloses a battery thermal runaway test fixture, which includes: a first clamping plate 10, a second clamping plate 20, a first insulation pad 40, a second insulation pad 50 and a heating plate 60: the second clamping plate 20 is arranged relative to the first clamping plate 10 to form a test space 30; the first insulation pad 40 is arranged in the test space 30 and is in contact with the first clamping plate 10; the second insulation pad 50 is arranged in the test space 30 and is in contact with the second clamping plate 20; the heating plate 60 is arranged in the test space 30, and the heating plate 60 is in contact with the first insulation pad 40 and there is a gap between the heating plate 60 and the second insulation pad 50 for accommodating the battery.

[0033] For example, the first splint 10 and the second splint 20 can be square plates arranged relatively parallel to each other, and the first insulation pad 40 and the second insulation pad 50 are respectively attached to the side surfaces of the first splint 10 and the second splint 20 close to each other. The input wire of the heating plate 60 can be led out along the gap between the first splint 10 and the second splint 20, or a hole can be opened on the first splint 10 for the lead-out of the wire.

[0034] For the sake of clarity, the present embodiment illustrates the application scenario of the test fixture. This is only one of the preferred methods of use of the present application, and the scope of protection of the present application cannot be limited accordingly. When the test fixture is assembled, the first insulation pad 40 and the second insulation pad 50 are first attached to the inner surfaces of the first clamping plate 10 and the second clamping plate 20 respectively, and then the heating plate 60 is attached to the surface of the first insulation pad 40, and by adjusting the relative spacing between the first clamping plate 10 and the second clamping plate 20, a test space 30 for accommodating the battery to be tested is formed between the heating plate 60 and the second insulation pad 50. During the test, the battery to be tested is placed in the gap, and pressure is applied by the first clamping plate 10 and the second clamping plate 20 so that both sides of the battery are tightly fitted to the heating plate 60, the first insulation pad 40 and the second insulation pad 50 respectively, and the heating plate 60 is started to heat the battery until thermal runaway is triggered.

[0035] Since the first thermal insulation pad 40 and the second thermal insulation pad 50 clamp the battery to be tested and the heating plate 60 as a whole, the dissipation rate of the battery heat is significantly reduced. Therefore, during the use of the test fixture of the embodiment, the heat provided by the heating plate 60 can be accumulated more in the battery and manifested as a temperature rise. The heating plate 60 can operate at a lower power and make the battery reach the temperature threshold of thermal runaway, triggering thermal runaway of the battery.

[0036] Compared to existing test fixtures, this embodiment can cause the battery to reach the temperature threshold, triggering thermal runaway, while using less heating power. During thermal runaway testing of thin batteries like blade batteries, this embodiment's test fixture can better protect the battery, preventing accidents such as explosions caused by localized overheating, thereby improving the accuracy and reliability of test results.

[0037] According to one embodiment of the present application, the test fixture further includes a temperature equalizing pad 70 , one side surface of the temperature equalizing pad 70 is in contact with the first thermal insulation pad 40 , and the other side surface of the temperature equalizing pad 70 is coplanar with the surface of the heating plate 60 away from the first thermal insulation pad 40 .

[0038] Exemplarily, the temperature-uniform pad 70 and the heating plate 60 are both square plates, and their thickness and width are consistent, and their length directions are consistent with the length direction of the first thermal insulation pad 40 .

[0039] The setting of the temperature-averaging pad 70 has the following effects. On the one hand, the temperature-averaging pad 70 cooperates with the heating plate 60 to make the stress distribution more uniform when the battery is under pressure, avoid excessive local pressure between the battery and the heating plate 60, and effectively prevent structural damage to the battery caused by mechanical stress concentration; on the other hand, the temperature-averaging pad 70 can quickly conduct the heat of the heating plate 60 to the battery area away from the heating plate 60, reduce the temperature difference between the various areas inside the battery, and make the overall heating process tend to be uniform, thereby avoiding local overheating, and better simulating the actual situation of overall heating of the battery in actual production.

[0040] Furthermore, the rigidity of the temperature-uniform plate 70 is the same as that of the heating plate 60 ; and / or, the material of the temperature-uniform plate 70 includes aluminum.

[0041] The temperature-equalizing pad 70 has the same stiffness as the heating plate 60, which makes the force on the battery facing the heating plate 60 and the temperature-equalizing pad 70 more uniform, making it less susceptible to mechanical damage. The temperature-equalizing pad 70 is made of aluminum, which provides excellent thermal conductivity, allowing the heat near the heating plate 60 to be better distributed throughout the battery.

[0042] According to one embodiment of the present application, the first thermal insulation pad 40 and the second thermal insulation pad 50 are thermal insulation foams with bubbles formed inside the thermal insulation foams. The volume of the thermal insulation pads is V1, the total volume of the bubbles is V2, and V2 ≥ 20% * V1.

[0043] This embodiment provides a specific option of a first thermal insulation pad 40 and a second thermal insulation pad 50. A bubble gap with a volume share of not less than 20% is formed inside the thermal insulation foam. The heat transfer is weakened by the air with low thermal conductivity, which can effectively suppress the heat loss of the battery.

[0044] According to one embodiment of the present application, the thickness of the first thermal insulation pad 40 and / or the second thermal insulation pad 50 is L1, 0.5 mm ≤ L1 ≤ 1.2 mm.

[0045] The thickness of the first insulation pad 40 and / or the second insulation pad 50 is related to the thermal insulation performance of the test fixture for the battery. If L1 is too small, the thermal insulation performance of the test fixture will be poor, and the battery will find it difficult to reach the thermal runaway threshold temperature; if L2 is too large, it will lead to waste of space and materials. 0.5mm≤L1≤1.2mm can make the test fixture as lightweight as possible while ensuring the thermal insulation performance of the test fixture.

[0046] According to one embodiment of the present application, the test fixture further includes a clamping assembly 80 , which is used to clamp the first clamping plate 10 and the second clamping plate 20 to compress the test space 30 .

[0047] The setting of the clamping assembly 80 enables the first clamping plate 10 and the second clamping plate 20 to maintain a tendency to approach each other during the test, the battery can be better clamped, the first insulation pad 40 and the second insulation pad 50 are wrapped more tightly, and the heat generated by the heating plate 60 can be more conducted to the battery. The test fixture does not require external settings to apply pressure, and is more convenient to use.

[0048] Furthermore, the first splint 10 is provided with a plurality of first holes 11, and the second splint 20 is provided with a plurality of second holes 21 corresponding to the first holes 11; the clamping assembly 80 includes a plurality of connecting rods 81 and a first fixing member 82 and a second fixing member 83 connected to both ends of the connecting rod 81, the connecting rod 81 is provided with one first hole 11 and one second hole 21, the first fixing member 82 is arranged on the side of the first splint 10 away from the second splint 20, and the second fixing member 83 is arranged on the side of the second splint 20 away from the first splint 10, and at least one of the first fixing member 82 and the second fixing member 83 is threadedly connected to the connecting rod 81.

[0049] This embodiment provides a specific implementation of a clamping assembly 80, in which a connecting rod 81 passes through a first hole 11 and a second hole 21, and a first fixing member 82 and a second fixing member 83 are respectively connected to the connecting rod 81 on the outside of the first clamping plate 10 and the second clamping plate 20, thereby limiting the relative distance between the first clamping plate 10 and the second clamping plate 20. The threaded connection between the first fixing member 82 and / or the second fixing member 83 and the connecting rod 81 makes the clamping assembly 80 easier to adjust, thereby facilitating the installation of the battery.

[0050] Exemplarily, the first fixing member 82 and the connecting rod 81 are respectively the nail head and the screw rod portion of a screw, and the second fixing member 83 is a nut threadedly connected to the screw.

[0051] According to one embodiment of the present application, the test fixture further includes a plurality of side panels 90 , the opposite side edges of the side panels 90 are respectively connected to the first clamping plate 10 and the second clamping plate 20 , and the first clamping plate 10 , the second clamping plate 20 and the side panels 90 together enclose a test space 30 .

[0052] This embodiment provides another test fixture structure, in which the first clamping plate 10, the second clamping plate 20 and the side plate 90 together form a test space 30, and the edge of the test space 30 is blocked by the side plate 90, which further limits the path for heat dissipation of the battery.

[0053] It is conceivable that the side panel 90 can have various sealing forms for the test space 30. The side panel 90 and the first and second plywood 10 and 20 can be combined to form a closed test space 30, or gaps can be left at both ends of the test space 30 to facilitate the wiring of the heating plate 60 and the operation of the battery explosion-proof valve.

[0054] According to one embodiment of the present application, the specifications of the heating plate 60 are determined based on the size of the battery, the contact area between the battery and the heating plate 60 is S1, the surface area of the battery facing the heating plate 60 is S2, and 25%*S2≤S1≤40%*S.

[0055] The contact area between the battery and the heating plate 60 affects the battery's heating efficiency. Typically, effective battery heating is achieved when the contact area between the heating plate 60 and the battery is less than half the surface area of a single side of the battery. Although fully enclosed heating can achieve a more uniform physical and thermodynamic state, from a cost-effective perspective, the size limit of 25%*S2≤S1≤40%*S can, on the one hand, reduce the cost of the test fixture while ensuring effective heating. On the other hand, by limiting the area of the heating plate 60, it can also be avoided from potentially deformed structures such as explosion-proof valves, preventing accidental damage to the heating plate 60 during testing.

[0056] Please also refer to Figure 3 As shown, Figure 3 It is a flow chart of the testing method provided in the embodiment of the present application.

[0057] To solve the above technical problems, the present application also provides a battery thermal runaway test method, which is based on any of the above battery thermal runaway test fixtures, and uses a first clamp 10 and a second clamp 20 to clamp the battery to be tested and then perform the test.

[0058] This test method is a method for performing thermal runaway testing using the above-mentioned test fixture disclosed above. Therefore, this test method also has the technical effects of the above-mentioned test fixture, that is, it can use a lower heating power to trigger thermal runaway of the battery, which has practical value in testing batteries with thin structures.

[0059] According to one embodiment of the present application, the battery includes an explosion-proof valve provided at one end thereof; performing a test includes: driving the heating plate 60 using a fixed power; if the explosion-proof valve opens and the battery does not explode when the battery temperature is stable, the test ends; if the explosion-proof valve does not open and the battery does not explode when the battery temperature is stable, increasing the fixed power until the explosion-proof valve opens; if the battery explodes, replacing the battery and reducing the fixed power to re-perform the test until the explosion-proof valve opens without the battery exploding.

[0060] Since battery parameters vary, there is a possibility that the battery may not experience thermal runaway and valve opening normally during the battery test. Therefore, this embodiment provides a further adjustment solution: if the battery temperature is stable, the explosion-proof valve is open and the battery does not explode, then the battery is normally triggered to experience thermal runaway and the battery's explosion-proof valve is working normally to release pressure, and the test is completed; if the battery temperature is stable, the explosion-proof valve does not open and the battery does not explode, it means that the power of the heating plate 60 is low, and the fixed power should be increased until the explosion-proof valve opens; if the battery explodes, it means that the power of the heating plate 60 is too high, and the battery should be replaced and the fixed power should be reduced until the explosion-proof valve opens without the battery exploding.

[0061] Furthermore, the testing method further includes: the heating plate 60 is disposed at an end of the battery away from the explosion-proof valve thereof.

[0062] The heating plate 60 is arranged at the end away from the battery explosion-proof valve, which has at least the following two advantages. On the one hand, the heating plate 60 is arranged at the end of the battery away from the explosion-proof valve, which makes the trigger point of battery thermal runaway away from the explosion-proof valve, making it more difficult to trigger the explosion-proof valve. Accordingly, if the battery explosion-proof valve can still be stably triggered under such extreme conditions, it means that the explosion-proof valve has considerable reliability during normal use. On the other hand, when the explosion-proof valve is opened, the process of the battery contents being ejected is destructive to a certain extent. Placing the heating plate 60 at the end of the battery away from the explosion-proof valve can avoid accidental damage to the heating plate 60 during the testing process.

[0063] Optionally, the testing method also includes: the specifications of the heating plate 60 are determined based on the size of the battery, the contact area between the battery and the heating plate 60 is S1, the surface area of the battery facing the heating plate 60 is S2, 25%*S2≤S1≤40%*S2; and / or, the power is 300W; and / or, the battery to be tested is a blade battery.

[0064] The size limitation of 25%*S2≤S1≤40%*S can, on the one hand, reduce the cost of the test fixture while ensuring the heating effect. On the other hand, by limiting the area of the heating plate 60, the heating plate 60 can also avoid structures that may be deformed, such as explosion-proof valves, to avoid accidental damage to the heating plate 60 during the test.

[0065] The fixed power is increased or decreased based on 300W, which is closer to the thermal runaway trigger power required for battery testing in this test method, and can reduce the number of tests.

[0066] In addition, this testing device is particularly suitable for testing thin batteries such as blade batteries. Specifically, due to the presence of the first thermal insulation pad 40 and the second thermal insulation pad 50, the heating plate 60 can stably heat the battery at a relatively low heating power and induce thermal runaway of the battery, thereby avoiding test distortion or even test failure caused by local overheating.

[0067] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship and movement status between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0068] It should also be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or indirectly connected to the other element through an intervening element.

[0069] In addition, the descriptions of "first", "second", etc. in this application are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0070] The above description is only a preferred embodiment of the present application and does not limit the patent scope of the present application. All equivalent structural transformations made based on the design concept of the present application and the contents of the present application description and drawings, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A battery thermal runaway test fixture, characterized in that: include: First splint; a second clamping plate, spaced apart from the first clamping plate to form a test space; A first thermal insulation pad is disposed in the test space and is in contact with the first plywood; A second thermal insulation pad is disposed in the test space and is in contact with the second plywood; A heating plate is arranged in the test space, and is arranged in contact with the first insulation pad and a gap exists between the heating plate and the second insulation pad for accommodating batteries.

2. The battery thermal runaway test fixture according to claim 1, characterized in that: The test fixture further includes a temperature-equalizing pad, one side surface of which is in contact with the first thermal insulation pad, and the other side surface of which is coplanar with the surface of the heating plate away from the first thermal insulation pad.

3. The battery thermal runaway test fixture according to claim 2, characterized in that: The rigidity of the temperature-averaging pad is the same as that of the heating plate; And / or, the material of the temperature balancing pad includes aluminum.

4. The battery thermal runaway test fixture according to claim 1, characterized in that: The first thermal insulation pad and the second thermal insulation pad are thermal insulation foams, bubbles are formed in the thermal insulation foams, the volume of the thermal insulation pads is V1, the total volume of the bubbles is V2, and V2≥20%*V1.

5. The battery thermal runaway test fixture according to claim 1, characterized in that: The thickness of the first thermal insulation pad and / or the second thermal insulation pad is L1, 0.5mm≤L1≤1.2mm.

6. The battery thermal runaway test fixture according to any one of claims 1 to 5, characterized in that: The test fixture further includes a clamping assembly configured to clamp the first clamping plate and the second clamping plate to compress the test space.

7. The battery thermal runaway test fixture according to claim 6, characterized in that: The first splint is provided with a plurality of first holes, and the second splint is provided with a plurality of second holes corresponding to the first holes; The clamping assembly includes multiple groups of connecting rods and first fixing parts and second fixing parts connected to the two ends of the connecting rods. The connecting rods are provided with one first hole and one second hole. The first fixing part is arranged on the side of the first clamping plate away from the second clamping plate, and the second fixing part is arranged on the side of the second clamping plate away from the first clamping plate. At least one of the first fixing part and the second fixing part is threadedly connected to the connecting rod.

8. The battery thermal runaway test fixture according to any one of claims 1 to 5, characterized in that: The test fixture further includes a plurality of side panels, opposite side edges of the side panels are respectively connected to the first clamping plate and the second clamping plate, and the first clamping plate, the second clamping plate and the side panels together enclose a test space.

9. The battery thermal runaway test fixture according to any one of claims 1 to 5, characterized in that: The specifications of the heating plate are determined based on the size of the battery. The contact area between the battery and the heating plate is S1, the surface area of the battery facing the heating plate is S2, and 25%*S2≤S1≤40%*S2.

10. A battery thermal runaway testing method, characterized in that: The testing method is based on the battery thermal runaway test fixture according to any one of claims 1 to 9, and the test is performed after the battery to be tested is clamped by the first clamp and the second clamp.

11. The battery thermal runaway testing method according to claim 10, characterized in that: The battery includes an explosion-proof valve provided at one end thereof; and the performing test includes: driving the heating plate with a fixed power; If the battery temperature is stable, the explosion-proof valve is open, and the battery does not explode, the test ends; If the battery temperature is stable, the explosion-proof valve is not opened, and the battery has not exploded, increasing the fixed power until the explosion-proof valve opens; If the battery explodes, the battery is replaced and the fixed power is reduced to re-perform the test until the explosion-proof valve opens without the battery exploding.

12. The battery thermal runaway testing method according to claim 11, characterized in that: The test method further comprises: The specifications of the heating plate are determined based on the size of the battery. The contact area between the battery and the heating plate is S1, and the surface area of the battery facing the heating plate is S2. 25%*S2≤S1≤40%*S2; And / or, the fixed power is 300W; And / or, the battery to be tested is a blade battery; And / or, the heating plate is arranged at an end of the battery away from the explosion-proof valve thereof.

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