Battery cell, battery pack and vehicle

Abstract

The utility model belongs to the technical field of vehicles, and particularly relates to a battery cell, a battery pack and a vehicle. Wherein the battery cell comprises a shell, a cell body, an anti-explosion valve and a temperature-sensitive material, the anti-explosion valve is arranged on the shell, the cell body and the temperature-sensitive material are both arranged in the shell, and the temperature-sensitive material can release gas when a preset temperature is reached. When the battery cell fails, the temperature of the battery cell begins to rise, when the temperature in the battery cell reaches the preset temperature, the temperature-sensitive material begins to release gas, the pressure in the battery cell is increased, and when the pressure in the battery cell is accumulated to the valve opening pressure, the anti-explosion valve is opened, the temperature of the battery cell does not reach the initial temperature of thermal runaway of the battery cell at the moment; and the temperature of the battery cell is reduced while the anti-explosion valve is opened, so that the possibility of thermal runaway of the battery cell is effectively reduced. Therefore, the temperature-sensitive material is arranged in the shell, so that the time for the battery cell to reach the valve opening pressure is shortened, the battery cell is enabled to open the valve at a safe temperature, the probability of firing and explosion of the battery pack is reduced, and the possibility of thermal runaway of the battery cell is reduced.

Description

Technical Field

[0001] This utility model relates to the field of vehicle technology, and in particular to a battery cell, a battery pack, and a vehicle. Background Technology

[0002] Battery cells can fail due to various reasons such as overcharging, short circuits, and external damage. When a cell fails, its temperature rises rapidly, generating a large amount of gas and causing a sharp increase in internal pressure. When the pressure exceeds the cell casing's tolerance limit, the explosion-proof valve opens to release the pressure and expel the high-temperature, high-pressure gas to prevent an explosion. However, to ensure that gases generated during daily use do not open the valve, the explosion-proof valve's opening threshold is often set too high. This means that by the time the cell begins its reaction and the valve opens, the heat has already accumulated to a point where the reaction cannot be interrupted. When the valve opens, the chain reaction within the cell is no longer prevented. The gas ejected after the valve opens is mostly flammable and explosive hydrogen and carbon monoxide, accompanied by high temperatures. If this gas is not released in time, it can lead to a fire and explosion of the battery pack. Utility Model Content

[0003] The purpose of this invention is to provide a battery cell, battery pack, and vehicle that shortens the time it takes for the battery cell to reach the valve opening pressure, allowing the battery cell to open the valve at a safer temperature, reducing the probability of battery pack fire and explosion, and reducing the possibility of battery cell thermal runaway.

[0004] To achieve this objective, the present invention adopts the following technical solution:

[0005] Battery cells, including:

[0006] shell;

[0007] The core is disposed within the outer casing;

[0008] An explosion-proof valve is installed on the housing;

[0009] A temperature-sensitive material is disposed inside the housing. The temperature-sensitive material can release gas when a preset temperature is reached, and the gas can flow to the explosion-proof valve.

[0010] As a preferred technical solution for battery cells, the preset temperature range is 80-200℃.

[0011] As a preferred technical solution for battery cells, the gas released by the temperature-sensitive material is an inert gas.

[0012] As a preferred technical solution for battery cells, the temperature-sensitive material is bicarbonate, urea, or azo compound.

[0013] As a preferred technical solution for the battery cell, a receiving member is provided in the gap between the outer shell and the core body, the receiving member has a receiving cavity, and the temperature-sensitive material is disposed in the receiving member.

[0014] As a preferred technical solution for the battery cell, the outer casing includes a housing and a cover that seals the opening of the housing, and the receiving member is disposed in the gap between the cover and the core.

[0015] As a preferred technical solution for the battery cell, the cavity of the receiving element has an opening, which is disposed opposite to the explosion-proof valve.

[0016] As a preferred technical solution for battery cells, the housing is provided with a breathable structure.

[0017] As a preferred technical solution for the battery cell, the volume of the housing is 50%-80% of the volume of the gap.

[0018] The battery pack includes the cells as described in any of the above embodiments.

[0019] The vehicle includes the battery pack described in the above scheme.

[0020] The beneficial effects of this utility model are:

[0021] This invention provides a battery cell comprising a casing, a core, an explosion-proof valve, and a temperature-sensitive material. The core is disposed within the casing, the explosion-proof valve is disposed on the casing, and the temperature-sensitive material is disposed within the casing. The temperature-sensitive material releases gas upon reaching a preset temperature. When the battery cell fails, its temperature begins to rise. When the temperature inside the cell reaches the preset temperature, the temperature-sensitive material reacts and releases gas, increasing the internal pressure of the cell. When the pressure inside the cell accumulates to the valve opening pressure, the explosion-proof valve opens. At this point, the cell temperature does not reach the initiation temperature of thermal runaway, and the cell temperature drops simultaneously with the opening of the explosion-proof valve, effectively reducing the possibility of thermal runaway. Therefore, by placing a temperature-sensitive material inside the casing, the time it takes for the cell to reach the valve opening pressure is shortened, allowing the cell to open the valve at a safer temperature, reducing the probability of battery pack fire and explosion, i.e., reducing the possibility of thermal runaway.

[0022] This invention also provides a battery pack, including the battery cell provided by this invention. By using the battery cell provided by this invention, the probability of battery pack fire and explosion is reduced.

[0023] This invention also provides a vehicle including the battery pack provided by this invention. By using the battery pack provided by this invention, the service life of the vehicle is improved. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the battery cell structure provided in an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the structure of the receiving component involved in the embodiments of this utility model;

[0026] Figure 3 This is a comparison chart of thermal runaway tests.

[0027] In the picture:

[0028] 10. Cover; 20. Core; 30. Electrode; 40. Electrode post; 50. Explosion-proof valve; 60. Container; 70. Temperature-sensitive material. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0030] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0031] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0032] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0033] like Figure 1 and Figure 2As shown, this embodiment provides a battery cell, including a casing, a core 20, an explosion-proof valve 50, and a temperature-sensitive material 70. The core 20 is disposed within the casing, the explosion-proof valve 50 is disposed on the casing, and the temperature-sensitive material 70 is disposed within the casing. The temperature-sensitive material 70 can release gas when a preset temperature is reached. When the battery cell fails, the cell temperature begins to rise. When the temperature inside the cell reaches the preset temperature, the temperature-sensitive material 70 begins to react and release gas, increasing the internal pressure of the cell. When the internal pressure accumulates to the valve opening pressure, the explosion-proof valve 50 opens. At this time, the cell temperature will not reach the starting temperature of thermal runaway, and the cell temperature drops simultaneously with the opening of the explosion-proof valve, effectively reducing the possibility of thermal runaway. Therefore, by placing the temperature-sensitive material 70 inside the casing, the time for the cell to reach the valve opening pressure is shortened, allowing the cell to open the valve at a safer temperature, reducing the probability of battery pack fire and explosion, i.e., reducing the possibility of thermal runaway.

[0034] The temperature-sensitive material 70 needs to be able to stably release gas within a preset temperature range to generate sufficient pressure to open the cell explosion-proof valve 50. In this embodiment, the preset temperature range for the temperature-sensitive material 70 to react is 80-200℃. The temperature-sensitive material 70 reacts within this temperature range, which can ensure that the time for the cell to reach the valve opening pressure is shortened, and at the same time, ensure that after the explosion-proof valve 50 is opened, the temperature of the cell will not reach the starting temperature of the cell thermal runaway.

[0035] The gas generated by the temperature-sensitive material 70 is preferably an inert gas. When the battery cell fails, the cell itself reacts to produce flammable gases such as hydrogen and carbon monoxide. The inert gas released by the temperature-sensitive material 70 mixes with the flammable gases produced by the cell's own reaction, which can dilute the concentration of flammable gases and further reduce the probability of battery pack fire and explosion, that is, further reduce the possibility of thermal runaway of the battery cell.

[0036] In addition to being able to stably release gas and / or generate inert gas within a preset temperature range, the temperature-sensitive material 70 also needs to meet the following requirements: the temperature-sensitive material 70 does not affect the normal performance of the battery cell, including not changing the chemical stability, conductivity or thermal stability of the battery cell; the temperature-sensitive material 70 should have good safety and avoid generating harmful substances or causing other safety problems at high temperatures.

[0037] Based on the above requirements, the temperature-sensitive material 70 can be selected from bicarbonates, such as sodium bicarbonate. Sodium bicarbonate begins to react at approximately 100°C, producing CO2 and water vapor. Alternatively, urea can be selected, which reacts at approximately 160°C, producing ammonia and CO2, with further reaction yielding nitrogen. Another option is an azo compound, such as azodicarbonamide, which begins to react at approximately 170°C, producing N2, NH3, and CO2. This demonstrates the versatility of the temperature-sensitive material 70, allowing for the selection of suitable materials for different battery cells, specifying valve opening times and temperatures, and enabling targeted design to achieve optimal performance for various battery cells. Furthermore, due to its temperature-sensitive characteristics, the temperature-sensitive material 70 remains stable under normal conditions, preventing the abnormal opening of the explosion-proof valve 50.

[0038] In this embodiment, a receiving member 60 is provided in the gap between the outer shell and the core 20. The receiving member 60 has a receiving cavity, and the temperature-sensitive material 70 is disposed in the receiving cavity of the receiving member 60. It is only necessary to place the temperature-sensitive material into the receiving cavity of the receiving member 60 and then assemble the receiving member 60 into the outer shell. The structure is simple and easy to implement.

[0039] Optionally, the outer casing includes a housing and a cover 10 sealing the opening of the housing. A receiving member 60 can be disposed in the gap between the cover 10 and the core 20. For example, the receiving cavity has an opening opposite to the explosion-proof valve 50, allowing the gas generated by the temperature-sensitive material 70 to directly act on the explosion-proof valve 50, thus shortening the response time. Furthermore, since the receiving member 60 obstructs the explosion-proof valve 50, a venting structure, such as vent holes or a venting mesh, is provided on the receiving member 60 to ensure that the gas generated by the thermal reaction of the battery cell can be smoothly discharged through the venting mechanism from the explosion-proof valve 50. For another example, the core 20 is provided with tabs 30, and electrode plates are welded to the tabs 30. The cover 10 is provided with pole posts 40, and pole posts 40 are provided with pole post holes. The electrode plates pass through the pole post holes and are welded to the pole post holes. The receiving member 60 can also be disposed between the pole post 40 and the core 20. Alternatively, the receiving member 60 can also be disposed in the gap between the core 20 and the side of the housing. It is understandable that, as long as the normal use requirements of the battery cell can be met, all gaps inside the casing can be used to install the housing 60, including but not limited to the positions listed above.

[0040] In this embodiment, the volume of the receiving member 60 is smaller than the volume of the gap, preferably between 50% and 80% of the gap volume. This ensures that the receiving member 60 can hold enough temperature-sensitive material 70 to generate enough gas to open the cell explosion-proof valve 50 in advance, and also prevents the receiving member 60 from obstructing the exhaust channel when the cell fails.

[0041] In other embodiments, the receiving member 60 may not be provided. Specifically, there are two scenarios: First, if the selected temperature-sensitive material 70 does not react harmfully with the existing materials within the battery cell, the temperature-sensitive material 70 can be coated onto a flexible member, and then the flexible member can be wrapped around the outside of the core 20 or between multiple cores 20. Alternatively, the temperature-sensitive material 70 can be dissolved in the electrolyte, doped into the positive and negative electrode materials, or coated onto the positive and negative electrodes. Second, if the selected temperature-sensitive material 70 will react harmfully with the existing materials within the battery cell, microencapsulation technology can be used to encapsulate the temperature-sensitive material 70 to prevent it from reacting with the materials within the battery cell. The encapsulated capsule structure can be placed in the gap between the outer shell and the core 20.

[0042] like Figure 2 As shown, taking the example of a container 60 positioned between the cover 10 and the core 20, an experiment was conducted. Sodium bicarbonate was placed in the container 60, and the volume of the sodium bicarbonate was approximately 60% of the volume of the container 60. Figure 3 As shown, in a set of thermal runaway tests, after the target cell ran away, heat was transferred from its large surface area to adjacent cells. At this time, the temperature of the large surface area of ​​the adjacent cells was approximately 280°C. In the design group, the gas production from sodium bicarbonate plus the gas production from the cell's own reaction reached the 50°C opening pressure of the explosion-proof valve at 320 seconds. The cell opened the valve prematurely, and the temperature of the large surface area of ​​the adjacent cells rapidly decreased by 50°C. Subsequently, the temperature of the large surface area of ​​the adjacent cells continued to decrease, and ultimately, the adjacent cells did not experience thermal runaway. In contrast, the control group did not have this design. When the cell's own reaction reached the valve opening pressure, it took 400 seconds, and no cooling occurred during the entire process, leading to thermal runaway of the adjacent cells and thermal diffusion in the battery pack. It should be noted that the target cell refers to the target cell that experienced thermal runaway.

[0043] The test results show that by setting the temperature-sensitive material 70, the explosion-proof valve 50 can respond in advance when the battery cell fails. After the explosion-proof valve 50 is opened, the temperature of the core 20 will continue to drop, which can effectively prevent the battery cell from thermal runaway and thus avoid the battery pack from catching fire and exploding.

[0044] This embodiment also provides a battery pack including the battery cells described above. By using the aforementioned battery cells, the probability of the battery pack catching fire and exploding is reduced.

[0045] This embodiment also provides a vehicle including the battery pack described above. By using the battery pack described above, the service life of the vehicle is improved.

[0046] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the protection scope of this utility model. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A battery cell, characterized in that, include: shell; The core (20) is disposed within the outer casing; An explosion-proof valve (50) is disposed on the housing; A temperature-sensitive material (70) is disposed inside the housing. The temperature-sensitive material (70) can release gas when a preset temperature is reached, and the gas can flow to the explosion-proof valve (50).

2. The battery cell according to claim 1, characterized in that, The preset temperature range is 80-200℃.

3. The battery cell according to claim 1, characterized in that, The gas released by the temperature-sensitive material (70) is an inert gas.

4. The battery cell according to claim 2 or 3, characterized in that, The temperature-sensitive material (70) is a bicarbonate, urea, or azo compound.

5. The battery cell according to any one of claims 1-3, characterized in that, A receiving member (60) is provided in the gap between the outer shell and the core (20). The receiving member (60) has a receiving cavity, and the temperature-sensitive material (70) is disposed in the receiving cavity.

6. The battery cell according to claim 5, characterized in that, The outer shell includes a housing and a cover (10) that covers the opening of the housing, and the receiving member (60) is disposed in the gap between the cover (10) and the core (20).

7. The battery cell according to claim 6, characterized in that, The receiving cavity has an opening, which is disposed opposite to the explosion-proof valve (50).

8. The battery cell according to claim 7, characterized in that, The receiving component (60) is provided with a breathable structure.

9. The battery cell according to claim 5, characterized in that, The volume of the receiving element (60) is 50%-80% of the volume of the gap.

10. A battery pack, characterized in that, Includes the battery cell as described in any one of claims 1-9.

11. A vehicle, characterized in that, Includes the battery pack as described in claim 10.

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