Battery cover and lithium-ion battery

Abstract

This utility model discloses a battery cover and a lithium-ion battery. The battery cover and the housing together define a cavity for accommodating the battery cell. The battery cover includes a first current collector, an insulating layer, and a second current collector. The first current collector is connected to the housing. The insulating layer is disposed on the first current collector. The second current collector includes a column and a connecting end, with the connecting end located on the side of the insulating layer opposite to the first current collector. The insulating layer is used to insulate the first current collector from the second current collector. The column defines a pressure relief cavity with an opening. A first pressure relief portion covers the opening and can open when the gas pressure inside the cavity is higher than a first preset value p, thereby connecting the pressure relief cavity with the cavity. Gas in the cavity flows to the pressure relief cavity, greatly reducing the risk of battery explosion. The battery cell is not directly connected to the external environment. Even as the gas pressure inside the cavity decreases, the battery cell still maintains a stable working environment, significantly reducing the risk of battery cell failure.

Description

Technical Field

[0001] The utility model relates to the technical field of energy storage equipment, in particular to a battery cover and a lithium ion battery. Background Art

[0002] When the ambient temperature rises or after long-term use, gas will be generated inside the battery. The generated gas pressure will cause the gas pressure inside the battery to gradually increase. When the gas pressure inside the battery rises to a certain value, it may cause the battery to explode and fail. In the prior art, the pressure relief part is often directly connected to the outside. After the pressure relief part is opened, the inside of the battery is connected to the outside, and the gas pressure inside the battery can be reduced. However, the chamber where the battery cell is located is directly connected to the outside, and the risk of battery cell failure is greatly increased. Utility Model Content

[0003] The main purpose of the utility model is to provide a battery cover and a lithium-ion battery, which can reduce the risk of battery cell failure caused by pressure release.

[0004] In order to achieve the above-mentioned purpose, the utility model proposes a battery cover, which together with the shell defines a housing cavity for accommodating a battery cell. The battery cover includes a first current collector, an isolation layer, a second current collector and a first pressure relief portion. The first current collector is connected to the shell; the isolation layer is arranged on the first current collector; the second current collector includes a column and a connection end, the connection end is arranged on the side of the isolation layer away from the first current collector, the isolation layer is used to insulate the first current collector from the second current collector, and the column limits a pressure relief cavity with an opening; the first pressure relief portion covers the opening, the initial air pressure of the pressure relief cavity is lower than the initial air pressure of the housing cavity, and the first pressure relief portion can be opened when the air pressure in the housing cavity is higher than a first preset value p, so that the pressure relief cavity is connected to the housing cavity; wherein the first preset value p satisfies: 0.5Mpa≤p≤6Mpa.

[0005] In some embodiments, the first pressure relief portion is configured as an aluminum-plastic film, the first pressure relief portion is welded to the wall surface of the column, and the encapsulation fusion depth h of the first pressure relief portion and the column satisfies: 30um≤h≤70um.

[0006] In some embodiments, the first current collector, the isolation layer, and the second current collector are stacked along a first direction. Along the first direction, a first thickness a of the first pressure relief portion and a second thickness b of the isolation layer satisfy: 0.08 mm≤a≤b.

[0007] In some embodiments, the first thickness a satisfies: 0.08 mm ≤ a ≤ 0.10 mm.

[0008] In some embodiments, the second thickness b satisfies: 0.08 mm ≤ b ≤ 0.15 mm.

[0009] In some embodiments, the battery cover also includes a second pressure relief portion, which can be opened when the air pressure in the pressure relief chamber is higher than a second preset value q, so that the gas in the pressure relief chamber can flow to the outside, wherein the second preset value q satisfies: 8Mpa≤q≤10Mpa.

[0010] In some embodiments, the second pressure relief portion is configured as an aluminum-plastic film, the first current collector, the isolation layer and the second current collector are stacked along the first direction, and along the first direction, a third thickness c of the second pressure relief portion satisfies: 0.08mm≤c≤0.10mm.

[0011] In some embodiments, the connection end is disposed on a side of the first current collector close to the accommodation cavity.

[0012] In some embodiments, the connection end is disposed on a side of the first current collector away from the accommodation cavity.

[0013] In some embodiments, the shell is provided with a slot, and the first current collector is snapped into the slot.

[0014] In some embodiments, the first current collector defines a through hole, the battery cover includes a pole, the pole is passed through the through hole, and a bending portion is provided at one end of the first current collector away from the pole, and the bending portion is connected to the shell.

[0015] In some embodiments, the battery cover further includes a reinforcement portion, the reinforcement portion is connected to the first current collector, and one side of the isolation layer is bonded to the reinforcement portion and the other side is bonded to the first current collector.

[0016] The second aspect of the present application further proposes a lithium-ion battery, which includes a battery cover plate of any of the above embodiments.

[0017] Compared with the prior art, the beneficial effects of the utility model are:

[0018] In the technical solution of the present application, the column of the second current collector is provided with a pressure relief chamber, and the initial air pressure of the pressure relief chamber is lower than the initial air pressure of the receiving chamber. When the air pressure in the receiving chamber reaches a set value, the gas in the container can trigger the first pressure relief part, so that the receiving chamber is connected to the pressure relief chamber, and the gas in the receiving chamber flows to the pressure relief chamber, and the air pressure in the receiving chamber is reduced, and the explosion risk of the battery is greatly reduced. In the technical solution of the present application, since the pressure relief chamber is provided in the column of the second current collector, the battery cell will not be directly connected to the external environment when the receiving chamber is depressurized, so that the battery cell still has a stable working environment while the air pressure in the receiving chamber is reduced, and the failure risk of the battery cell is greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the utility model 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 utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0020] Figure 1 This is a schematic diagram of the top view of the battery cover in one embodiment of the utility model;

[0021] Figure 2 It is a schematic diagram of the assembly structure of the battery cover and the shell in one embodiment of the utility model, wherein the shell is provided with a slot, and the second current collector protrudes toward the side away from the accommodating cavity to form a column;

[0022] Figure 3 It is a schematic diagram of the assembly structure of the battery cover, the shell and the battery cell in one embodiment of the utility model, wherein the shell is provided with a slot, and the second current collector protrudes toward the side close to the accommodating cavity to form a column;

[0023] Figure 4 It is a schematic diagram of the assembly structure of the battery cover and the shell in one embodiment of the utility model, wherein the shell is provided with a slot, the second current collector protrudes toward the side away from the accommodating cavity to form a column, and the battery cover is also provided with a reinforcement portion;

[0024] Figure 5 It is a schematic diagram of the assembly structure of the battery cover and the shell in one embodiment of the utility model, wherein the first current collector is provided with a bending portion, and the second current collector protrudes toward the side close to the accommodating cavity to form a column;

[0025] Figure 6 This is a schematic diagram of the assembly structure of a battery cover and a shell in an embodiment of the utility model, wherein the first current collector is provided with a bending portion, and the second current collector protrudes toward a side away from the accommodating cavity to form a column.

[0026] Description of Figure Numbers:

[0027] Battery cover 100;

[0028] First current collector 110; through hole 111; bent portion 112;

[0029] An isolation layer 120;

[0030] Second current collector 130; column 131; opening 1311; pressure relief chamber 1312; connection end 132;

[0031] A first pressure relief portion 140;

[0032] A second pressure relief portion 150;

[0033] reinforcement part 160;

[0034] Lithium-ion battery 200;

[0035] Housing 210; card slot 211; accommodating cavity 220; battery cell 230;

[0036] First direction X;

[0037] first thickness a;

[0038] second thickness b;

[0039] The third thickness c.

[0040] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0042] When the ambient temperature rises or after long-term use, gas will be generated inside the battery. The generated gas pressure will cause the gas pressure inside the battery to gradually increase. When the gas pressure inside the battery rises to a certain value, it may cause the battery to explode and fail. In the prior art, the pressure relief part is often directly connected to the outside. After the pressure relief part is opened, the inside of the battery is connected to the outside, and the gas pressure inside the battery can be reduced. However, the chamber where the battery cell is located is directly connected to the outside, and the risk of battery cell failure is greatly increased.

[0043] To solve the above technical problems, Figures 1 to 6 As shown, the present application provides a battery cover 100, which together with a housing 210 defines a receiving cavity 220 for receiving a battery cell 230. The battery cover 100 includes a first current collector 110, an isolation layer 120 and a second current collector 130.

[0044] like Figure 2As shown, the first current collector 110 is connected to the shell 210. The first current collector 110 can be annular or rectangular. The first current collector 110 can be provided with a through hole 111, and the column 131 of the second current collector 130 can be penetrated through the through hole 111. Specifically, the first current collector 110 can be configured as a steel ring. The second pressure relief portion 150 is configured as an aluminum-plastic film, and the first current collector 110, the isolation layer 120 and the second current collector 130 are stacked along the first direction X. In the direction perpendicular to the first direction X, the diameter value of the steel ring can be any suitable value within 6mm to 16mm, and the thickness value of the steel ring along the first direction X can be any suitable value from 3.5mm to 16mm. Specifically, the thickness value of the side of the steel ring close to the column 131 can be any suitable value from 3.5mm to 12.5mm, and the thickness value of the side of the steel ring away from the column 131 can be any suitable value from 6mm to 16mm. The thickness of the first current collector 110 is not less than 3.5 mm, which can effectively improve the strength of the battery cover plate 100 and reduce the risk of deformation of the battery cover plate 100.

[0045] like Figure 3 As shown, the isolation layer 120 is disposed on the first current collector 110, and the isolation layer 120 can be configured as any suitable colloid. When the isolation layer 120 is configured as a colloid, on the one hand, the insulator can insulate and isolate the first current collector 110 from the second current collector 130, and on the other hand, the isolation layer 120 can also make the first current collector 110 and the second current collector 130 bonded together to form the battery cover 100.

[0046] like Figure 2 As shown, the second current collector 130 includes a column 131 and a connection end 132, the connection end 132 is arranged on the side of the isolation layer 120 away from the first current collector 110, the isolation layer 120 is used to insulate the first current collector 110 from the second current collector 130, and the column 131 limits a pressure relief cavity 1312 having an opening 1311. Specifically, the initial air pressure in the pressure relief cavity 1312 can be 0Mpa, 0.1Mpa, 0.2Mpa, 0.3Mpa, 0.35Mpa, 0.4Mpa or any air pressure value lower than 0.5Mpa.

[0047] like Figure 4 As shown, the first pressure relief portion 140 covers the opening 1311, the initial air pressure of the pressure relief chamber 1312 is lower than the initial air pressure of the accommodating chamber 220, and the first pressure relief portion 140 can be opened when the air pressure in the accommodating chamber 220 is higher than the first preset value p, so that the pressure relief chamber 1312 is connected to the accommodating chamber 220. The first preset value p satisfies: 0.5Mpa≤p≤6Mpa. The first preset value p can be any suitable air pressure value such as 0.5Mpa, 0.6Mpa, 0.7Mpa, 1Mpa, 1.5Mpa, 1.8Mpa, 2Mpa, 4Mpa, 5Mpa, 5.5Mpa or 6Mpa.

[0048] It should be noted that if Figure 2 , Figure 3 as well as Figure 4 As shown, the size and shape of the pressure relief chamber 1312 can be determined according to the actual size of the column 131 and the pressure relief requirements of the battery. Specifically, the column 131 can be a cylinder or a prism, etc. When the column 131 is a cylinder, the diameter of the column 131 can be any suitable value between 7 mm and 16 mm. The opening 1311 of the pressure relief chamber 1312 in the column 131 can be a circular opening 1311. Similarly, the diameter of the opening 1311 can be any suitable value between 6 mm and 16 mm. In some embodiments, in order to improve the strength of the column 131, the difference between the diameter of the opening 1311 and the diameter of the column 131 is not less than 1 mm. The pressure relief chamber 1312 can be configured as a cylindrical cavity, a conical cavity or a truncated cone cavity, etc. In some embodiments, the pressure relief chamber 1312 is a combination of a cylindrical cavity and a truncated cone cavity. Along the first direction X, the diameter of the truncated cone cavity gradually decreases, thereby enhancing the strength of the top of the column 131. Specifically, the thickness of the top of the column 131 can be any suitable value from 0.1 mm to 0.15 mm. Along the first direction X, the height of the column 131 can be any suitable value from 0.6 mm to 0.65 mm. In order to increase the volume of the pressure relief chamber 1312, the height of the truncated cone cavity in the pressure relief chamber 1312 can be no greater than the height of the cylindrical cavity.

[0049] In the technical solution of the present application, the column 131 of the second current collector 130 is provided with a pressure relief chamber 1312, and the initial air pressure of the pressure relief chamber 1312 is lower than the initial air pressure of the accommodating chamber 220. When the air pressure in the accommodating chamber 220 reaches a set value, the gas in the container can trigger the first pressure relief portion 140, so that the accommodating chamber 220 is connected with the pressure relief chamber 1312, and the gas in the accommodating chamber 220 flows to the pressure relief chamber 1312, and the air pressure in the accommodating chamber 220 is reduced, and the explosion risk of the battery is greatly reduced. In the technical solution of the present application, since the pressure relief chamber 1312 is provided in the column 131 of the second current collector 130, the battery cell 230 will not be directly connected to the external environment when the accommodating chamber 220 is depressurized, so that the battery cell 230 still has a stable working environment while the air pressure in the accommodating chamber 220 is reduced, and the failure risk of the battery cell 230 is greatly reduced.

[0050] The first pressure relief part 140 may be a film that can burst when the air pressure increases to an appropriate value. The first pressure relief part 140 may also be a gas valve that can cooperate with an air pressure sensor. The controller can control the opening and closing of the gas valve according to the detection value of the gas sensor. Figure 4As shown, in this embodiment, the first pressure relief portion 140 is configured as an aluminum-plastic film, and the first pressure relief portion 140 is welded to the wall surface of the column 131. The encapsulation fusion depth h of the first pressure relief portion 140 and the column 131 satisfies: 30um≤h≤70um. That is, the welding fusion depth between the aluminum-plastic film and the column 131 can be any suitable value such as 30um, 40um, 50um, 65um or 70um. The aluminum-plastic film is welded to the column 131. When the air pressure in the accommodating cavity 220 reaches the first preset value p, the aluminum-plastic film can be separated from the column 131 under the pressure of the gas in the accommodating cavity 220, so that the opening 1311 is connected to the accommodating cavity 220. In some embodiments, the aluminum-plastic film can also be preset with a blasting trajectory, that is, the aluminum-plastic film can be provided with a notch, and when the air pressure in the accommodating cavity 220 reaches the first preset value p, the aluminum-plastic film can be broken from the notch, so that the gas in the accommodating cavity 220 flows to the pressure relief cavity 1312. The aluminum-plastic film has low cost, convenient pressure relief, and good stability, which helps the battery cell 230 to operate stably.

[0051] The first pressure relief portion 140 can be configured as an aluminum-plastic film, and the isolation layer 120 can be configured as any suitable colloid such as ethyl cyanoacrylate. In order to reduce the risk of the gas in the accommodating cavity 220 breaking through the isolation layer 120 when the gas pressure reaches the first preset value p, or the isolation layer 120 being separated from the first current collector 110 and the second current collector 130, the thickness of the isolation layer 120 can be not less than the thickness of the aluminum-plastic film. Figure 3 As shown, in this embodiment, the first current collector 110, the isolation layer 120 and the second current collector 130 are stacked along the first direction X. Along the first direction X, the first thickness a of the first pressure relief portion 140 and the second thickness b of the isolation layer 120 satisfy: 0.08mm≤a≤b. Specifically, the thickness of the aluminum-plastic film is not less than 0.08mm, which helps the aluminum-plastic film to stably separate the accommodating cavity 220 and the pressure relief cavity 1312 when the pressure of the accommodating cavity 220 does not reach the first preset value. If the second thickness b is not less than the first thickness a, the risk of failure of the isolation layer 120 when the other accommodating cavity 220 reaches the first preset value p is greatly reduced. In some embodiments, the first thickness a satisfies: 0.08mm≤a≤0.10mm, and the second thickness b satisfies: 0.08mm≤b≤0.15mm. Specifically, the first thickness a can be 0.08mm, 0.09mm, 0.095mm or 0.10mm. The second thickness b can be 0.08mm, 0.09mm, 0.095mm, 0.10mm, 0.12mm, 0.13mm, 0.14mm or 0.15mm. In some embodiments, the first pressure relief portion 140 can be configured as a circular aluminum-plastic film, and the diameter of the first pressure relief portion 140 can be any suitable value from 3mm to 11mm, as long as the aluminum-plastic film can cover the opening 1311 and be welded to the column 131.

[0052] In some embodiments, to further reduce the risk of excessive pressure inside the battery, the battery cover 100 may further include a second pressure relief portion 150. In some embodiments, the second pressure relief portion 150 may be configured as a one-way valve, that is, the gas can only flow from the pressure relief chamber 1312 to the outside. Here, the outside refers to the chamber or external environment outside the accommodating chamber 220 and the pressure relief chamber 1312. Figure 1 as well as Figure 5 As shown, in this embodiment, the battery cover 100 also includes a second pressure relief portion 150, which can be opened when the air pressure in the pressure relief chamber 1312 is higher than the second preset value q, so that the gas in the pressure relief chamber 1312 can flow to the outside, wherein the second preset value q satisfies: 8Mpa≤q≤10Mpa. Specifically, the second preset value q can be 8Mpa, 9Mpa, 9.5Mpa or 10Mpa. The second preset value q is not less than the first preset value p, that is, the accommodating chamber 220 can first be depressurized in the pressure relief chamber 1312 through the first pressure relief portion 140, and the second pressure relief portion 150 is opened when the pressure in the pressure relief chamber 1312 reaches the second preset value q, and the pressure in the pressure relief chamber 1312 can be further released. The provision of the second pressure relief portion 150 enables the battery cover 100 to achieve multi-stage pressure relief of the accommodating chamber 220, and the pressure relief capacity of the battery cover 100 is greatly improved. It should be noted that if the second pressure relief portion 150 is connected to the external environment, there is also a pressure relief chamber 1312 between the battery cell 230 in the accommodating chamber 220 and the outside. The technical solution of the present application can still provide a good working environment for the battery cell 230 and reduce the risk of failure of the battery cell 230.

[0053] In some embodiments, the second pressure relief portion 150 may also be configured as an aluminum-plastic film, and the first current collector 110, the isolation layer 120, and the second current collector 130 are stacked along the first direction X. Along the first direction X, the third thickness c of the second pressure relief portion 150 satisfies: 0.08 mm ≤ c ≤ 0.10 mm. Specifically, the third thickness c may be 0.08 mm, 0.09 mm, or 0.10 mm. Figure 3 As shown, in some embodiments, the second pressure relief portion 150 can be configured as a circular aluminum-plastic diaphragm, and the valve diameter of the second pressure relief portion 150 can be any suitable value from 2mm to 5mm. Similarly, the column 131 can also be provided with a hole connected to the pressure relief portion, and the second pressure relief portion 150 covers this hole. The second pressure relief portion 150 can be laser welded to the column 131. Specifically, the encapsulation fusion depth of the second pressure relief portion 150 and the column 131 can be any suitable value from 30um to 65um. In some embodiments, the second pressure relief portion 150 can also be provided with notches to assist in blasting pressure relief, which will not be repeated here.

[0054] According to different usage requirements, the connection end 132 can be arranged on a side of the first current collector 110 close to the accommodation cavity 220, or the connection end 132 can be arranged on a side of the first current collector 110 away from the accommodation cavity 220. Figure 6 As shown, in this embodiment, along the first direction X, the first current collector 110, the isolation layer 120 and the connection end 132 are sequentially arranged. Figure 3 As shown, in this embodiment, a connection end 132, an isolation layer 120 and a first current collector 110 are provided in sequence. The column 131 is connected to the connection end 132. Specifically, the second current collector 130 may protrude toward one side of the accommodating cavity 220 to form the column 131, or the second current collector 130 may protrude toward the side away from the accommodating cavity 220 to form the column 131, which is not limited here. Figure 3 The column 131 is disposed on a side of the connection end 132 close to the accommodating cavity 220 , and the volume of the battery cover 100 can be effectively reduced.

[0055] According to different usage requirements, the first current collector 110 can be connected to the housing 210 in different ways. Figure 2 , Figure 3 as well as Figure 4 As shown, in some embodiments, the housing 210 may be provided with a slot 211, and the first current collector 110 may be snap-fitted into the slot 211. Figure 5 as well as Figure 6 As shown, in some embodiments, the first current collector 110 defines a through hole 111 , the pole is passed through the through hole 111 , and a bending portion 112 is provided at one end of the first current collector 110 away from the pole, and the bending portion 112 is connected to the shell 210 .

[0056] like Figure 4 As shown, in some embodiments, the battery cover 100 may further include a reinforcing portion 160, the reinforcing portion 160 is connected to the first current collector 110, and one side of the isolation layer 120 is bonded to the reinforcing portion 160 and the other side is bonded to the first current collector 110. The provision of the reinforcing portion 160 can improve the strength of the first current collector 110 on the one hand, and enhance the connection stability between the isolation layer 120 and the first current collector 110 on the other hand, thereby greatly reducing the risk of the second current collector 130 being separated from the first current collector 110.

[0057] like Figure 3 As shown, the second aspect of the present application also provides a lithium-ion battery 200, which includes the battery cover 100 of any of the above embodiments. The lithium-ion battery 200 may also include a shell 210 and a battery cell 230. The shell 210 and the battery cover 100 together limit a receiving cavity 220 for accommodating the battery cell 230. Thanks to the improvement of the above-mentioned battery cover 100, the battery cover 100 of this embodiment has the same technical effect as the above-mentioned battery cover 100, which will not be repeated here.

[0058] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0059] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the utility model, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or", "and / or" or "and / or" appears in the full text, its meaning includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the utility model.

[0060] The above are only preferred embodiments of the present invention, and do not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the utility model concept, or directly / indirectly used in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A battery cover, which together with a shell defines a receiving cavity for receiving a battery cell, characterized in that: The battery cover comprises: A first current collector connected to the housing; An isolation layer, provided on the first current collector; a second current collector, comprising a column and a connection end, wherein the connection end is arranged on a side of the isolation layer away from the first current collector, the isolation layer is used to insulate the first current collector from the second current collector, and the column limits a pressure relief cavity with an opening; A first pressure relief portion covers the opening, the initial air pressure of the pressure relief chamber is lower than the initial air pressure of the accommodating chamber, and the first pressure relief portion can be opened when the air pressure in the accommodating chamber is higher than a first preset value p to connect the pressure relief chamber with the accommodating chamber; wherein the first preset value p satisfies: 0.5Mpa≤p≤6Mpa.

2. The battery cover according to claim 1, characterized in that: The first pressure relief portion is configured as an aluminum-plastic film, the first pressure relief portion is welded to the wall surface of the column, and the encapsulation fusion depth h of the first pressure relief portion and the column satisfies: 30um≤h≤70um.

3. The battery cover according to claim 2, characterized in that: The first current collector, the isolation layer, and the second current collector are stacked along a first direction. Along the first direction, a first thickness a of the first pressure relief portion and a second thickness b of the isolation layer satisfy: 0.08 mm≤a≤b.

4. The battery cover according to claim 3, characterized in that: The first thickness a satisfies: 0.08 mm ≤ a ≤ 0.10 mm; and / or, The second thickness b satisfies: 0.08 mm ≤ b ≤ 0.15 mm.

5. The battery cover according to claim 1, characterized in that: The battery cover also includes a second pressure relief portion, which can be opened when the air pressure in the pressure relief chamber is higher than a second preset value q, so that the gas in the pressure relief chamber can flow to the outside, wherein the second preset value q satisfies: 8Mpa≤q≤10Mpa.

6. The battery cover according to claim 5, characterized in that: The second pressure relief portion is configured as an aluminum-plastic film, the first current collector, the isolation layer and the second current collector are stacked along a first direction, and along the first direction, a third thickness c of the second pressure relief portion satisfies: 0.08 mm≤c≤0.10 mm.

7. The battery cover according to claim 1, characterized in that: The connecting end is arranged on a side of the first current collector close to the accommodation cavity; or, The connecting end is arranged on a side of the first current collector away from the accommodating cavity.

8. The battery cover according to claim 1, characterized in that: The housing is provided with a slot, and the first current collector is connected to the slot; and / or, The first current collector defines a through hole, the battery cover includes a pole, the pole is passed through the through hole, and a bending portion is provided at one end of the first current collector away from the pole, and the bending portion is connected to the shell.

9. The battery cover according to claim 1, characterized in that: The battery cover plate further includes a reinforcement portion, which is connected to the first current collector. One side of the isolation layer is bonded to the reinforcement portion, and the other side of the isolation layer is bonded to the first current collector.

10. A lithium ion battery, characterized in that: A battery cover comprising the battery cover according to any one of claims 1 to 9.

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