Method for testing high temperature resistance of fireproof material of power battery

Abstract

The invention provides a method for testing the high-temperature-resistant characteristic of a fireproof material of a power battery. The testing method comprises the following steps: obtaining the fireproof material of the power battery; a plurality of to-be-tested points are determined on the fireproof material, the center positions of every two adjacent to-be-tested points are spaced by a first preset distance, and the first preset distance is determined based on the distance between pressure release valves of every two adjacent battery cells in the power battery; impacting the plurality of to-be-tested points by using a heat source; and after the impact is finished, testing the high-temperature-resistant characteristic of the fireproof material. According to the method for testing the high-temperature-resistant characteristic of the fireproof material of the power battery, the multiple to-be-tested points are determined on the fireproof material, and then the multiple to-be-tested points are impacted through the heat source, so that the impact effect on the same section of the fireproof material when multiple battery cells in the power battery are subjected to thermal runaway can be simulated; the triggering process of the battery cell when thermal diffusion occurs is considered, the impact on the fireproof material in the actual process is close, and the high-temperature-resistant characteristic of the obtained fireproof material is more accurate.

Description

Technical Field

[0001] The present application relates to the field of automotive battery technology, and in particular to a method for testing the high temperature resistance of fireproof materials for power batteries. Background Art

[0002] The safety of power batteries has become an important factor restricting the development of new energy vehicles. As a major cause of fire in new energy vehicles, the risk of thermal diffusion will increase with the increase of energy density of new energy vehicle batteries. Mica, glass fiber and other products are the main thermal diffusion protection materials in the industry. They are applied above the module and can directly withstand the impact of high-temperature gas during the eruption of the battery cell.

[0003] At present, the industry usually tests the high temperature resistance of fireproof materials by using a 1000℃ heat source for 30 minutes and then observing the state of the sample. However, this method does not take into account the actual triggering process of the battery cell when heat diffusion occurs, and its accuracy is low. Summary of the invention

[0004] In order to at least partially solve the above-mentioned problems, an embodiment of the present application provides a testing method for the high temperature resistance characteristics of a fireproof material for a power battery, the testing method comprising: obtaining a fireproof material for a power battery; determining a plurality of points to be tested on the fireproof material, the center positions of two adjacent points to be tested being a first preset distance apart, the first preset distance being determined based on the distance between the pressure relief valves of two adjacent battery cells in the power battery; using a heat source to impact the plurality of points to be tested; after the impact, testing the high temperature resistance characteristics of the fireproof material.

[0005] In some embodiments, when a heat source is used to impact a plurality of test points, the impact temperature value is greater than a preset temperature, and the preset temperature is determined based on the temperature of the gas ejected when a cell of the power battery has thermal runaway.

[0006] In some embodiments, when a heat source is used to impact multiple points to be tested, the impact time is greater than a first preset time, and the first preset time is determined based on the continuous eruption time when a single battery cell of the power battery has thermal runaway.

[0007] In some embodiments, when a heat source is used to impact multiple points to be tested, multiple impacts are performed on the same point to be tested, and the time interval between two adjacent impacts is less than a second preset time, and the second preset time is determined based on the trigger interval of the battery cell of the power battery.

[0008] In some embodiments, when a heat source is used to impact a plurality of points to be tested, a spraying area of ​​the heat source is greater than or equal to a preset area, and the preset area is determined based on an area of ​​a cell pressure relief valve of the power battery.

[0009] In some embodiments, when a heat source is used to impact multiple points to be tested, the distance between the heat source and the points to be tested is a second preset distance, and the second preset distance is determined based on the distance between the battery cell spray valve of the power battery and the upper cover of the battery pack.

[0010] In some embodiments, when a heat source is used to impact a plurality of points to be tested, the plurality of points to be tested are impacted sequentially.

[0011] In some embodiments, when testing the high temperature resistance of the fireproof material, the dielectric strength and tensile strength of the fireproof material are tested.

[0012] In some embodiments, the heat source is an acetylene gun heat source.

[0013] The embodiment of the present application provides a testing method for the high temperature resistance characteristics of fireproof materials for power batteries. By determining multiple points to be tested on the fireproof material, with the center positions of two adjacent points to be tested being a first preset distance apart, and then impacting the multiple points to be tested through a heat source, it can simulate the impact effect on the same section of fireproof material when thermal runaway occurs in multiple battery cells in a power battery, taking into account the triggering process of the battery cells when heat diffusion occurs, and is close to the impact received by the fireproof material in the actual process, so that the high temperature resistance characteristics of the fireproof material obtained are more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 these drawings without paying creative labor.

[0015] Figure 1 It is a schematic diagram of the fireproof material when the method for testing the high temperature resistance of the fireproof material for a power battery provided in the embodiment of the present application is carried out. DETAILED DESCRIPTION

[0016] The technical scheme of the preferred embodiment of the present application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection claimed in the present application.

[0017] The words "first", "second" and similar words used in this application do not indicate any order, quantity or importance, but are only used to distinguish different parts. The words "include" or "comprise" and similar words mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of including other elements. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0018] Combination Figure 1 , an embodiment of the present application provides a method for testing the high temperature resistance of fireproof materials for power batteries, the testing method comprising: obtaining fireproof materials for power batteries; determining a plurality of points to be tested on the fireproof materials, the center positions of two adjacent points to be tested being a first preset distance apart, the first preset distance being determined based on the distance between the pressure relief valves of two adjacent cells in the power battery; using a heat source to impact the plurality of points to be tested; after the impact, testing the high temperature resistance of the fireproof materials. In this embodiment, the fireproof material is obtained by cutting a new material, or by directly disassembling it from the power battery. The fireproof material may be a structure at the upper cover of the battery pack of the power battery for isolating the cell from the external environment. Exemplarily, the fireproof material may be in the shape of strips. A plurality of points to be tested may be arranged in a straight line on the fireproof material. When the cells in the power battery have thermal runaway, multiple cells may impact the fireproof material. Therefore, in this embodiment, multiple test points are determined on the fireproof material, and the center positions of two adjacent test points are separated by a first preset distance. The first preset distance can be the distance between the pressure relief valves of two adjacent cells in the power battery. Then, the multiple test points are impacted by a heat source, which can be closer to the impact of multiple cells on the fireproof material in real situations. Figure 1 , Figure 1 The serial numbers 1, 2, 3, 4, 5, ..., X can be the serial numbers of multiple test points, that is, Figure 1 The number of points to be tested in is X, A can be the length of the spray area of ​​the heat source at the point to be tested, B can be the width of the spray area of ​​the heat source at the point to be tested, and C can be the first preset distance. In some embodiments, when testing the high temperature resistance of the fireproof material, the dielectric strength and tensile strength of the fireproof material can be tested to evaluate the insulation performance and structural strength of the fireproof material. In some embodiments, the heat source is an acetylene gun heat source, which is easy to obtain and has a good effect of simulating impact. Of course, in other embodiments, it can also be other types of heat sources.

[0019] The embodiment of the present application provides a testing method for the high temperature resistance characteristics of fireproof materials for power batteries. By determining multiple points to be tested on the fireproof material, with the center positions of two adjacent points to be tested being a first preset distance apart, and then impacting the multiple points to be tested through a heat source, it can simulate the impact effect on the same section of fireproof material when thermal runaway occurs in multiple battery cells in a power battery, taking into account the triggering process of the battery cells when heat diffusion occurs, and is close to the impact received by the fireproof material in the actual process, so that the high temperature resistance characteristics of the fireproof material obtained are more accurate.

[0020] In some embodiments, when a heat source is used to impact multiple test points, the impact temperature value is greater than a preset temperature, and the preset temperature is determined based on the temperature of the gas emitted when the power battery cell is in thermal runaway. Exemplarily, the impact temperature value is >α°C, which is used to simulate the temperature of the gas emitted when the cell is in thermal runaway. In this embodiment, this method can be closer to the actual working conditions during thermal runaway, making the measurement results more accurate.

[0021] In some embodiments, when a heat source is used to impact multiple points to be tested, the impact time is greater than a first preset time, and the first preset time is determined based on the continuous eruption time when a single battery cell of the power battery has thermal runaway. Exemplarily, the impact time is > a min, which is used to simulate the continuous eruption time when a single battery cell has thermal runaway, and the specific value of a can be selected according to the form of the battery cell. In this embodiment, this method can be closer to the actual working conditions during thermal runaway, making the measurement results more accurate.

[0022] In some embodiments, when a heat source is used to impact multiple points to be tested, the same point to be tested is impacted multiple times, and the time interval between two adjacent impacts is less than a second preset time, and the second preset time is determined based on the trigger interval of the battery cell of the power battery. Exemplarily, the impact interval <b min is used to simulate the trigger interval of the battery cell, and the specific value of b is selected according to the protection scheme of the power battery module. In this embodiment, this method can be closer to the actual working conditions during thermal runaway, making the measurement results more accurate.

[0023] In some embodiments, when a heat source is used to impact multiple test points, the spray area of ​​the heat source is greater than or equal to a preset area, and the preset area is determined based on the area of ​​the battery cell pressure relief valve of the power battery. For example, the spray area ≥ A*Bmm 2 , to simulate the area of ​​the battery cell pressure relief valve, and the specific values ​​of A and B are selected according to the actual area of ​​the pressure relief valve. In this embodiment, this method can be closer to the actual working condition during thermal runaway, making the measurement result more accurate.

[0024] In some embodiments, when a heat source is used to impact multiple points to be tested, the distance between the heat source and the points to be tested is a second preset distance, and the second preset distance is determined based on the distance between the battery cell spray valve of the power battery and the upper cover of the battery pack. Exemplarily, the distance from the flame gun head of the heat source to the point to be tested on the fireproof material is Y mm, which is used to simulate the distance between the battery cell spray valve and the upper cover of the battery pack. In this embodiment, this method can be closer to the actual working conditions during thermal runaway, making the measurement results more accurate.

[0025] In some embodiments, when a heat source is used to impact multiple points to be tested, the multiple points to be tested are impacted sequentially. In this embodiment, this method can complete the test by using one heat source, avoiding the increase of additional test costs.

[0026] The test method for the high temperature resistance of fireproof materials for power batteries provided in the embodiments of the present application utilizes existing test equipment, improves some test parameters, and takes into account various factors such as the eruption temperature, eruption time, and trigger interval of the battery cell. It can more accurately simulate the actual failure process of the battery cell during heat diffusion without any additional cost increase.

[0027] Based on the above-mentioned embodiments of the present application, in the absence of explicit negation or conflict, the technical features of one embodiment may be beneficially combined with one or more other embodiments.

[0028] Although some specific embodiments of the present application have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are only for illustration and not for limiting the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified or some technical features may be replaced by equivalents without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A method for testing the high temperature resistance of fireproof materials for power batteries, characterized in that: include: Obtain fireproof materials for power batteries; Determine a plurality of points to be tested on the fireproof material, wherein the center positions of two adjacent points to be tested are separated by a first preset distance, and the first preset distance is determined based on the distance between the pressure relief valves of two adjacent battery cells in the power battery; Using a heat source to impact the plurality of points to be tested; After the impact, the high temperature resistance of the fireproof material is tested.

2. The testing method according to claim 1, characterized in that: When a heat source is used to impact the plurality of points to be tested, the impact temperature value is greater than a preset temperature, and the preset temperature is determined based on the temperature of the gas ejected when the battery cell of the power battery has thermal runaway.

3. The testing method according to claim 1, characterized in that: When a heat source is used to impact the plurality of points to be tested, the impact time is greater than a first preset time, and the first preset time is determined based on a continuous eruption time when a single battery cell of the power battery has thermal runaway.

4. The testing method according to claim 1, characterized in that: When a heat source is used to impact the multiple points to be tested, multiple impacts are performed on the same point to be tested, and the time interval between two adjacent impacts is less than a second preset time, and the second preset time is determined based on the trigger interval of the battery cell of the power battery.

5. The testing method according to claim 1, characterized in that: When a heat source is used to impact the plurality of points to be tested, a spraying area of ​​the heat source is greater than or equal to a preset area, and the preset area is determined based on an area of ​​a cell pressure relief valve of the power battery.

6. The testing method according to claim 1, characterized in that: When a heat source is used to impact the multiple points to be tested, the distance between the heat source and the points to be tested is a second preset distance, and the second preset distance is determined based on the distance between the battery cell spray valve of the power battery and the battery pack cover.

7. The testing method according to claim 1, characterized in that: When the heat source is used to impact the multiple points to be tested, the multiple points to be tested are impacted sequentially.

8. The testing method according to claim 1, characterized in that: When testing the high temperature resistance of the fireproof material, the dielectric strength and tensile strength of the fireproof material are tested.

9. The testing method according to claim 1, characterized in that: The heat source is an acetylene gun heat source.

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