Battery cell cover plate assembly, battery cell, battery pack and automobile

Abstract

The utility model provides a battery cell cover plate assembly, a battery cell, a battery pack and an automobile, and relates to the technical field of automobile parts. The battery cell cover plate assembly comprises a fire extinguishing sheet, a cover plate patch and a cover plate body provided with an anti-explosion valve, the cover plate patch is attached to the outer side of the cover plate body and comprises a patch fixed part and a patch movable part which are connected, and the patch movable part is configured to be capable of deflecting relative to the patch fixed part in the direction away from the cover plate body; the fire extinguishing piece is arranged on the side, facing the cover plate body, of the patch moving part, and the fire extinguishing piece is opposite to the anti-explosion valve. When the cell does not have thermal runaway, the patch movable part does not deflect relative to the patch fixed part, at the moment, the patch movable part and the patch fixed part are attached to the surface of the cover plate body, and the occupied space can be basically ignored; when the battery cell is subjected to thermal runaway, the patch movable part can only deflect to a small extent relative to the patch fixed part so as to meet the pressure relief requirement of the battery cell, and other space in a battery pack cannot be excessively occupied.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of automobile parts, specifically, relates to a battery cell cover plate assembly, battery cell, battery pack and automobile. BACKGROUND

[0002] With the continuous development of new energy technology, the new energy market is expanding, and the development of new energy vehicles cannot be separated from the support of battery technology, therefore, the development trend and market prospect analysis of new energy vehicle battery technology become the current hot spot. Compared with traditional fuel vehicles, new energy vehicles have a self-ignition fire phenomenon, and in severe cases, explosion may occur, and the source of the fire is mainly the battery pack, and the source of the battery pack fire is the smallest battery unit in the battery pack - the battery cell, therefore, in the prior art, in order to improve the safety performance of the battery pack, some battery cell covers are equipped with fire extinguishing devices, but the setting of these fire extinguishing devices either occupies a large internal space of the battery cell shell or occupies a large battery pack space outside the battery cell. SUMMARY

[0003] The utility model aims at solving at least one of the above technical problems.

[0004] In order to solve the above problems, the utility model provides a battery cell cover plate assembly, which comprises a fire extinguishing piece, a cover plate patch and a cover plate body provided with an explosion-proof valve, the cover plate patch is attached to the outer side of the cover plate body, and comprises a patch fixed part and a patch movable part connected with each other, the patch fixed part is fixed with the cover plate body, the patch movable part is configured to be deflected relative to the patch fixed part in a direction away from the cover plate body, the fire extinguishing piece is arranged on the side of the patch movable part facing the cover plate body, and the fire extinguishing piece is opposite to the explosion-proof valve.

[0005] The battery cell cover plate assembly provided by the utility model has the following technical effects compared with the prior art, but is not limited to the following technical effects:

[0006] If the battery cell is in thermal runaway, the high temperature and high pressure vaporized electrolyte inside the battery cell can break the rupture disc to spray out to achieve pressure relief, and the high temperature and high pressure vaporized electrolyte sprayed out of the rupture disc can further force the patch movable part to fold away from the cover plate body relative to the patch fixed part, thereby ensuring that the patch movable part does not hinder the normal pressure relief of the battery cell interior. At the moment when the high temperature and high pressure vaporized electrolyte is sprayed out of the rupture disc, the fire extinguishing sheet corresponding to the rupture disc, such as the outer layer of the nano microcapsule film of the perfluoroethyl ketone fire extinguishing sheet, will immediately break, and then the internal perfluoroethyl ketone fire extinguishing agent will be automatically sprayed out, and the sprayed perfluoroethyl ketone fire extinguishing agent will cool and extinguish the battery cell to prevent the surrounding electrical components from being affected. Wherein, the fire extinguishing sheet is installed on the outside of the cover plate body (i.e. the side away from the inside of the battery cell) through the cover plate patch, when the battery cell is not in thermal runaway, the patch movable part does not fold relative to the patch fixed part, at this time the patch movable part and the patch fixed part are both attached to the surface of the cover plate body, that is, the cover plate patch is attached to the surface of the cover plate body, and the space occupied is basically negligible; when the battery cell is in thermal runaway, the patch movable part can only fold relative to the patch fixed part to a small extent to meet the pressure relief requirement of the battery cell, and the patch movable part folded to a small extent will not occupy much space in the battery pack.

[0007] Further, a line-shaped weak part is arranged on the cover plate patch, and the line-shaped weak part divides the cover plate patch into the patch fixed part and the patch movable part.

[0008] Further, a projection of the rupture disc on the patch movable part falls within the edge contour of the fire extinguishing sheet.

[0009] Further, the patch movable part is bonded to the cover plate body, and the bonding force between the patch movable part and the cover plate body is less than the burst pressure of the rupture disc.

[0010] Further, the maximum folding angle of the patch movable part relative to the patch fixed part is in the range of (0°, 60°].

[0011] Further, a limiting protrusion is arranged on the side of the patch fixed part away from the cover plate body, and / or a limiting protrusion is arranged on the side of the patch movable part away from the cover plate body; the limiting protrusion is used to limit the folding angle of the patch movable part relative to the patch fixed part.

[0012] Further, the fire extinguishing sheet is a perfluoroethyl ketone fire extinguishing sheet.

[0013] The utility model discloses still provide a kind of battery, including the battery as described above.

[0014] Since the technical improvement and technical effect of the battery are the same as the battery cover plate assembly, the battery will not be described again.

[0015] The utility model discloses still provide a kind of battery, including the battery as described above.

[0016] Since the technical improvement and technical effect of the battery are the same as the battery, the battery will not be described again.

[0017] The utility model discloses still provide a kind of automobile, including the battery as described above.

[0018] Since the technical improvement and technical effect of the automobile are the same as the battery, the automobile will not be described again. DRAWINGS

[0019] Figure 1 It is the connection structure schematic view of the cover plate body in the cover plate assembly and the shell of battery of the utility model embodiment;

[0020] Figure 2 It is the structure schematic view of the cover plate patch and fire extinguishing piece installation in the cover plate body before the cover plate assembly in the utility model embodiment;

[0021] Figure 3 It is the structure schematic view of the cover plate patch and fire extinguishing piece in the cover plate assembly of the utility model embodiment;

[0022] Figure 4 It is the structure schematic view of the patch movable part relative patch fixed part deflection in the battery of the utility model embodiment;

[0023] Figure 5 It is the installation structure schematic view of the shell and second cover plate assembly of the battery of the utility model embodiment;

[0024] Figure 6 It is the structure schematic view of the patch movable part relative patch fixed part deflection.

[0025] MARK NO.

[0026] 1, fire extinguishing piece;2, cover plate patch;21, patch fixed part;22, patch movable part;23, linear weak part;24, limit protrusion;3, cover plate body;4, explosion-proof valve;5, negative output pole;6, positive cover plate body;61, liquid injection port;7, positive output pole;8, positive cover plate patch;9, shell;10, insulating film. DETAILED DESCRIPTION

[0027] In order to make the above objectives, characteristics and advantages of the present application more apparent, obvious and understandable, the specific embodiments of the present application will be described in detail below with reference to the drawings.

[0028] In the description of the present application, it should be understood that the terms "upper", "lower", "left", "right", "front", "back" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as limiting the present application in that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation.

[0029] Furthermore, in the drawings, the X-axis represents the longitudinal direction, and the positive direction of the X-axis represents the front, and the negative direction of the X-axis represents the back; in the drawings, the Y-axis represents the transverse direction, and the positive direction of the Y-axis represents the left, and the negative direction of the Y-axis represents the right; in the drawings, the Z-axis represents the vertical direction, that is, the up-down direction, and the positive direction of the Z-axis represents the up, and the negative direction of the Z-axis represents the down.

[0030] It should be noted that the aforementioned X-axis, Y-axis and Z-axis represent only the meaning for the convenience of describing the present application and simplifying the description, and are not indicative or suggestive of the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application.

[0031] Referring to Figures 1-4 , the electric cell cover plate assembly of the present application embodiment comprises a fire extinguishing sheet 1, a cover plate patch 2 and a cover plate body 3 provided with an explosion-proof valve 4, the cover plate patch 2 is attached to the outer side of the cover plate body 3, comprising a patch fixed part 21 and a patch movable part 22 connected together, the patch fixed part 21 is fixed with the cover plate body 3, the patch movable part 22 is configured to be deflected relative to the patch fixed part 21 in a direction away from the cover plate body 3, the fire extinguishing sheet 1 is arranged on the side of the patch movable part 22 facing the cover plate body 3, and the fire extinguishing sheet 1 is opposite to the explosion-proof valve 4.

[0032] In this embodiment, after the electric cell cover plate assembly is installed at the opening of one end of the shell 9 of the electric cell, if the electric cell occurs thermal runaway, the high temperature and high pressure vaporized electrolyte generated inside the electric cell will cause the explosion-proof valve 4 to break and spray out to achieve pressure relief, and the high temperature and high pressure vaporized electrolyte sprayed out of the explosion-proof valve 4 can further force the patch movable part 22 to deflect relative to the patch fixed part 21 in a direction away from the cover plate body 3, thereby ensuring that the patch movable part 22 will not hinder the normal pressure relief of the inside of the electric cell.

[0033] In the moment when the high-temperature and high-pressure vaporized electrolyte is sprayed out from the explosion-proof valve 4, the fire extinguishing sheet 1 corresponding to the explosion-proof valve 4 will immediately break under high temperature and high pressure, and then the internal perfluorohexone extinguishing agent will be automatically sprayed out, and the sprayed perfluorohexone extinguishing agent will cool and extinguish the battery cell to prevent the surrounding electrical components from being affected.

[0034] The fire extinguishing sheet 1 is installed on the outer side of the cover plate body 3 (i.e. the side away from the inside of the battery cell) through the cover plate patch 2. When the battery cell does not have thermal runaway, the patch movable part 22 does not deflect relative to the patch fixed part 21, and at this time, the patch movable part 22 is the same as the patch fixed part 21, which is attached to the surface of the cover plate body 3, i.e. the cover plate patch 2 is attached to the surface of the cover plate body 3 as a whole, and the occupied space is basically negligible. When the battery cell has thermal runaway, the patch movable part 22 can only deflect to a small extent relative to the patch fixed part 21 to meet the pressure relief requirement of the battery cell. The patch movable part 22 that deflects to a small extent does not excessively occupy other space (space other than the battery cell) in the battery pack, thereby improving the integration of the battery cell and the battery pack.

[0035] In the embodiment, as described above, the cover plate patch 2 is arranged on the outer side of the cover plate body 3, and the fire extinguishing sheet 1 corresponding to the explosion-proof valve 4 is arranged on the cover plate patch 2, which can control the thermal runaway of the battery cell in a targeted manner, thereby inhibiting the safety problems such as thermal diffusion of the thermal runaway battery cell. By improving the intrinsic safety of the battery cell, the safety and reliability of the battery system are improved. Moreover, the arrangement of the cover plate patch 2 and the fire extinguishing sheet 1 does not occupy the internal space of the battery cell, and the space occupied by the cover plate patch 2 and the fire extinguishing sheet 1 in the battery pack outside the battery cell is almost negligible, which can improve the energy density of the battery pack and reduce the safety protection cost of the battery system.

[0036] As described above, the fire extinguishing sheet 1 can be a perfluoroketone fire extinguishing sheet. The perfluorohexone fire extinguishing sheet 1 is not only mature in technology, but also easy to obtain in the market. The perfluorohexone fire extinguishing sheet 1 adopts a nano-microcapsule compression technology to store the high-efficiency and environmentally friendly perfluorohexone extinguishing agent inside. As long as the adhesive on the back is torn off, it can be arbitrarily pasted near the fire prevention area (in the embodiment, the perfluoroketone fire extinguishing sheet is pasted on the side of the patch movable part 22 facing the explosion-proof valve 4). Once the surrounding temperature reaches 140°C or there is an open flame (the temperature of the vaporized electrolyte sprayed out of the battery cell is about 200°C), the outer nano-microcapsule film of the perfluoroketone fire extinguishing sheet will immediately break, and the internal perfluorohexone extinguishing agent will be automatically sprayed out to extinguish the fire in the budding stage. Moreover, the perfluoroketone fire extinguishing sheet has a sheet structure and can be arbitrarily cut into the required length and width.

[0037] Specifically, when the battery cell does not occur thermal runaway, the high-temperature and high-pressure vaporized electrolyte is sprayed out from the explosion-proof valve 4, the outer nano-microcapsule film of the perfluoroacetone fire extinguishing sheet breaks immediately, and then the internal perfluorohexanone fire extinguishing agent is automatically sprayed out. The sprayed perfluorohexanone fire extinguishing agent absorbs heat and immediately evaporates to form vaporized perfluorohexanone, which cools the sprayed high-temperature vaporized electrolyte, thereby preventing the high-temperature vaporized electrolyte from spreading to other electrical components. When the battery cell does not occur thermal runaway and high-pressure electrolyte is sprayed out, there is sometimes a risk of flame spraying. The vaporized perfluorohexanone quickly thins the oxygen around the flame, thereby controlling the spread of the fire, timely extinguishing the fire source, and ultimately avoiding the fire and explosion of the battery cell after thermal runaway.

[0038] It should be noted that the fire extinguishing sheet 1 can be a perfluoroacetone fire extinguishing sheet, but is not limited to a perfluoroacetone fire extinguishing sheet. For example, in other embodiments, the fire extinguishing sheet 1 can also be an alcohol type fire extinguishing sheet, a fluorinated fire extinguishing sheet, a compound based fire extinguishing sheet, etc.

[0039] Referring to Figures 2-3 Optionally, a line-shaped weak part 23 is arranged on the cover sheet 2, and the line-shaped weak part 23 divides the cover sheet 2 into the sheet fixed part 21 and the sheet movable part 22.

[0040] In this embodiment, the line-shaped weak part 23 is arranged on the cover sheet 2, and the cover sheet 2 is divided into the sheet fixed part 21 and the sheet movable part 22 by the line-shaped weak part 23, and the sheet movable part 22 can be bent relative to the sheet fixed part 21. In the case that the battery cell does not occur thermal runaway, the sheet movable part 22 is in an initial state of being coplanar with the sheet fixed part 21, that is, the two are at an included angle of 180°, and at this time the sheet movable part 22 is also attached to the cover body 3. When the sheet movable part 22 of the cover sheet 2 is pressed by the vaporized electrolyte in the initial state, the cover sheet 2 can be bent at the line-shaped weak part 23, so that the sheet movable part 22 is deflected relative to the sheet fixed part 21 and no longer attached to the cover body 3 (as shown in FIG. 8), so as to ensure that the battery cell can be relieved. Figure 4

[0041] It can be understood that the line-shaped weak part 23 extends along the width direction (X-axis direction) of the cover sheet 2. For example, the line-shaped weak part 23 can be a plurality of through grooves arranged in sequence along the width direction of the cover sheet 2. For another example, the line-shaped weak part 23 is two recessed grooves arranged on the two side surfaces of the cover sheet 2. The two recessed grooves do not penetrate the cover sheet 2 in thickness, and the recessed grooves penetrate the cover sheet 2 along the width direction of the cover sheet 2. Alternatively, the line-shaped weak part 23 can also be a crease structure. The cover sheet 2 can be made of a high-temperature resistant plastic material, which will not be burned by the sprayed high-temperature vaporized electrolyte and has a relatively light weight.

[0042] ​Optionally, the projection of the explosion-proof valve 4 on the patch movable part 22 falls within the edge profile of the fire extinguishing sheet 1.

[0043] In this embodiment, when the patch movable part 22 is not deflected relative to the patch fixed part 21, that is, the battery cell does not have thermal runaway, the fire extinguishing sheet 1 on the patch movable part 22 is not only arranged opposite the explosion-proof valve 4, but the area of the fire extinguishing sheet 1 is also greater than or equal to the area of the explosion-proof valve 4. In this way, when the battery cell has thermal runaway, and at the moment when the patch movable part 22 is about to be deflected, the fire extinguishing sheet 1 has sufficient area to spray fire extinguishing agent to comprehensively cool and extinguish the vaporized electrolyte.

[0044] Optionally, the patch movable part 22 is bonded to the cover plate body 3, and the bonding force between the patch movable part 22 and the cover plate body 3 is less than the burst pressure of the explosion-proof valve 4.

[0045] In this embodiment, when the patch movable part 22 is not deflected relative to the patch fixed part 21, that is, the battery cell does not have thermal runaway, the patch movable part 22 is bonded to the cover plate body 3, which can ensure that the patch movable part 22 does not accidentally deflect. For example, through the bonding force between the patch movable part 22 and the cover plate body 3, the patch movable part 22 will not deflect relative to the patch fixed part 21 when the car is vibrating or braking. Only when the battery cell has thermal runaway, the patch movable part 22 will deflect relative to the patch fixed part 21. Specifically, when the battery cell has thermal runaway, the high-temperature and high-pressure vaporized electrolyte inside the battery cell can burst the explosion-proof valve 4. In the case where the bonding force between the patch movable part 22 and the cover plate body 3 is less than the burst pressure of the explosion-proof valve 4, the high-temperature and high-pressure vaporized electrolyte sprayed from the explosion-proof valve 4 can naturally force the patch movable part 22 and the cover plate body 3 to separate, thereby driving the patch movable part 22 to deflect relative to the patch fixed part 21.

[0046] Optionally, the maximum deflection angle of the patch movable part 22 relative to the patch fixed part 21 is in the range of (0°, 60°].

[0047] In this embodiment, the angle of the patch movable part 22 relative to the patch fixed part 21 is the angle at which the patch movable part 22 deflects. Specifically, the initial angle between the patch movable part 22 and the patch fixed part 21 is 180°, and the angle between the patch movable part 22 and the patch fixed part 21 after the maximum deflection of the patch movable part 22 relative to the patch fixed part 21 can be controlled to be not less than 120°, that is, the change in the angle of the patch movable part 22 relative to the patch fixed part 21 after deflection is not more than 60°. In other words, the angle between the patch movable part 22 and the cover plate body 3 in the initial state is 0°, and the angle between the patch movable part 22 and the cover plate body 3 after the patch movable part 22 deflects relative to the patch fixed part 21 is not less than 60°. Figure 4As shown, after the patch movable part 22 deflects to its maximum extent, the angle α between the patch movable part 22 and the cover plate body 3 is less than or equal to 60°. For example, by controlling the angle α between the patch movable part 22 and the cover plate body 3 after the patch movable part 22 deflects to its maximum extent to be 10°, on the one hand, it can be ensured that the outer side of the cover plate body 3 of the battery cell does not need to leave too much clearance space, thereby reducing the occupation of the internal space of the battery pack; on the other hand, it also ensures that after the patch movable part 22 deflects to its maximum extent relative to the patch fixing part 21, the fire extinguishing disc 1 on the patch movable part 22 is still in a position roughly opposite to the explosion-proof valve 4, and the fire extinguishing disc 1 is in a position very close to the explosion-proof valve 4, ensuring that after the extinguishing agent sprayed by the fire extinguishing disc 1 evaporates, it can form an oxygen-isolated isolation layer around the explosion-proof valve 4, resulting in a good cooling and fire extinguishing effect.

[0048] See Figure 6 Optionally, the patch fixing part 21 is provided with a limiting protrusion 24 on the side away from the cover plate body 3, and / or the patch moving part 22 is provided with a limiting protrusion 24 on the side away from the cover plate body 3; the limiting protrusion 24 is used to limit the deflection angle of the patch moving part 22 relative to the patch fixing part 21.

[0049] In this embodiment, in order to control the maximum deflection of the patch movable part 22, that is, in order to control Figure 4 The maximum value of the midpoint angle α can be achieved by providing a limiting protrusion 24 on the outer side of the patch fixing part 21. When the patch movable part 22 deflects relative to the patch fixing part 21 and abuts against the limiting protrusion 24, the patch movable part 22 cannot deflect further and reaches the maximum degree of deflection. Alternatively, a limiting protrusion 24 can be provided on the outer side of the patch movable part 22. When the limiting protrusion 24 on the deflected patch movable part 22 abuts against the outer surface of the patch fixing part 21, the patch movable part 22 cannot deflect further and reaches the maximum degree of deflection.

[0050] Another embodiment of the present invention provides a battery cell, including a battery cell cover assembly and a housing 9 as described above. One end of the housing 9 is provided with a first opening. The cover body 3 of the battery cell cover assembly is placed over the first opening. The cover patch 2 is located on the side of the cover body 3 away from the internal space of the housing 9.

[0051] Since the technological improvements and effects of the battery cell are the same as those of the battery cell cover assembly, the battery cell will not be described in detail again.

[0052] Alternatively, the battery cell can be as follows: Figures 1-2 and Figures 4-5The shown blade cell, when the cell is a blade cell, the length direction of the cell shell 9 is provided with a first opening and a second opening respectively, the cell cover plate assembly is arranged at the first opening, and the cell cover plate assembly can be a negative cover plate assembly, and the cover plate body 3 of the negative cover plate assembly is further provided with a negative output pole 5. In addition, the blade cell further comprises a positive cover plate assembly, the positive cover plate assembly comprises a positive cover plate body 6 and a positive cover plate patch 8, the positive cover plate body 6 is arranged at the second opening of the shell 9, and the positive cover plate body 6 is further provided with a positive output pole 7 and a liquid injection port 61, the positive cover plate patch 8 is arranged on the outer side of the positive cover plate body 6, and the shell 9 can be further wrapped with an insulating film 10, and the insulating film 10 and the positive cover plate patch 8 and the cover plate patch 2 of the negative cover plate assembly together realize the insulation of the cell and external electrical components, and ensure safety.

[0053] Of course, in other embodiments, the cell with the aforementioned cell cover plate assembly can also be a square cell, a cylindrical cell, etc.

[0054] A battery pack according to another embodiment of the present application comprises the cell as described above.

[0055] Since the technical improvement and technical effect of the battery pack are the same as those of the cell, the battery pack will not be described again.

[0056] A vehicle according to another embodiment of the present application comprises the battery pack as described above.

[0057] Since the technical improvement and technical effect of the vehicle are the same as those of the battery pack, the vehicle will not be described again.

[0058] The terms "first" and "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first" and "second" can explicitly or implicitly include at least one of the features.

[0059] Although the present application is disclosed as above, the protection scope of the present application is not limited to this. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and these changes and modifications will fall within the protection scope of the present application.

Claims

1. An electrochemical cell cover plate assembly, comprising: The fire extinguishing sheet (1), the cover plate patch (2) and the cover plate body (3) provided with the explosion-proof valve (4), the cover plate patch (2) is attached to the outer side of the cover plate body (3), including the patch fixed part (21) and the patch movable part (22) connected, the patch fixed part (21) is fixed with the cover plate body (3), the fire extinguishing sheet (1) is arranged on the side of the patch movable part (22) towards the cover plate body (3), and the fire extinguishing sheet (1) is opposite to the explosion-proof valve (4); the patch movable part (22) is configured to be deflected relative to the patch fixed part (21) in the direction away from the cover plate body (3) under the forcing action of the electrolyte sprayed by the explosion-proof valve (4), so as to realize the pressure relief of the battery cell.

2. The cell cover plate assembly of claim 1, wherein, The cover plate patch (2) is provided with a line type weak part (23), and the line type weak part (23) divides the cover plate patch (2) into the patch fixed part (21) and the patch movable part (22).

3. The cell cover plate assembly of claim 1, wherein, The projection of the explosion-proof valve (4) on the patch movable part (22) falls within the edge contour of the fire extinguishing sheet (1).

4. The cell cover plate assembly of claim 1, wherein, The patch movable part (22) is bonded with the cover plate body (3), and the bonding force between the patch movable part (22) and the cover plate body (3) is less than the explosion opening pressure of the explosion-proof valve (4).

5. The cell cover plate assembly of claim 1, wherein, The maximum deflection angle of the patch movable part (22) relative to the patch fixed part (21) ranges from (0°, 60°].

6. The cell cover plate assembly of claim 1, wherein, The side of the patch fixed part (21) away from the cover plate body (3) is provided with a limiting protrusion (24), and / or the side of the patch movable part (22) away from the cover plate body (3) is provided with a limiting protrusion (24); the limiting protrusion (24) is used to limit the deflection angle of the patch movable part (22) relative to the patch fixed part (21).

7. The cell cover plate assembly of any of claims 1-6, wherein, The fire extinguishing sheet (1) is a perfluoroacetone fire extinguishing sheet.

8. An electric cell characterized by The battery cell cover plate assembly and the shell (9) are included, and one end of the shell (9) is provided with a first opening, and the cover plate body (3) of the battery cell cover plate assembly is arranged at the first opening.

9. A battery pack, characterized by, The battery cell as claimed in claim 8 is included.

10. An automobile characterized by comprising: The battery pack as claimed in claim 9 is included.

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