CN216413130U

CN216413130U - Battery monomer, battery package and electric device

Info

Publication number: CN216413130U
Application number: CN202122384735.7U
Authority: CN
Inventors: 王慢慢; 范玉磊; 葛销明
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2021-09-29
Filing date: 2021-09-29
Publication date: 2022-04-29
Anticipated expiration: 2031-09-29

Abstract

The utility model discloses a battery monomer, battery package and electric installation include: a battery case; the battery comprises a battery shell, an electrode assembly and a battery cover, wherein the electrode assembly is arranged in the battery shell and comprises a positive plate, a negative plate and an isolating membrane, and the isolating membrane is arranged between the positive plate and the negative plate; and the buffer sheet is arranged between the battery shell and the electrode assembly, is made of an elastic material and is provided with a plurality of holes. The buffer sheet can effectively absorb the expansion force of the electrode assembly and reduce the internal pressure of the battery monomer, and a plurality of holes are formed in the buffer sheet and can contain gas generated by the electrode assembly, so that the internal pressure of the battery monomer is further reduced.

Description

Battery monomer, battery package and electric device

Technical Field

The utility model relates to a battery technology field especially relates to a battery monomer, battery package and electric installation.

Background

A secondary battery is a battery cell in which an active material can be activated by charging after discharge to continue use. Secondary batteries are widely used in electronic devices such as mobile phones, notebook computers, battery cars, electric automobiles, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, electric tools, and the like. The secondary battery can include a cadmium nickel battery cell, a hydrogen nickel battery cell, a lithium ion battery cell, a secondary alkaline zinc-manganese battery cell, and the like.

The secondary battery mainly includes a case, an electrode assembly, a current collecting member, and a cap assembly. The electrode assembly is formed by winding or stacking a positive electrode plate, a negative electrode plate and a separation film. The secondary battery expands during charge and discharge, and releases a large expansion force to the outside. If the secondary battery is excessively swelled, it may cause deterioration in battery performance, affecting the safety in use and the lifespan of the secondary battery.

SUMMERY OF THE UTILITY MODEL

Therefore, a battery cell is needed to solve the technical problem that battery swelling affects battery performance.

In order to achieve the above object, the present invention provides a battery cell, including:

a battery case;

the battery comprises a battery shell, an electrode assembly and a battery cover, wherein the electrode assembly is arranged in the battery shell and comprises a positive plate, a negative plate and an isolation film, and the isolation film is arranged between the positive plate and the negative plate; and

the buffer sheet is arranged between the battery shell and the electrode component and made of elastic materials, and a plurality of holes are formed in the buffer sheet.

In the technical scheme, the buffer sheet is arranged between the battery shell and the electrode assembly, the buffer sheet is made of elastic materials, the expansion force of the electrode assembly can be effectively absorbed, the internal pressure of the battery monomer is reduced, and the buffer sheet is provided with the holes which can contain gas generated by the electrode assembly, so that the internal pressure of the battery monomer is further reduced.

Furthermore, more than two rows of holes are arranged on the buffer sheet at intervals, and each row is provided with more than two holes.

In the technical scheme, the holes are arranged on the buffer sheet at intervals in a row, so that hollow parts distributed with the holes and solid parts without the holes are formed on the buffer sheet, gas generated by the electrode assembly can be effectively absorbed, and meanwhile, the solid parts can be ensured to provide enough elastic supporting force for the electrode assembly.

Furthermore, the hole is a saccular cavity structure with an opening, and the opening is positioned on the surface of the buffer sheet.

In the above technical solution, the hole is a bag-shaped cavity structure having an opening, and the gas generated by the electrode assembly enters the hole of the bag-shaped cavity structure through the opening, and the bag-shaped cavity structure can enable the hole to contain more gas.

Furthermore, the opening is provided with a one-way breathable film, and the air inlet direction of the one-way breathable film is from the outside of the hole to the inside of the hole.

In above-mentioned technical scheme, set up one-way ventilated membrane at the opening of hole, and one-way ventilated membrane only allows gas to get into the hole, and the gas in the hole can't return outside the hole to ensure that battery monomer internal gas pressure is stable.

Further, the battery case includes a wide face and a narrow face; the buffer sheet is arranged between the wide surface and the electrode assembly.

In the technical scheme, because the expansion amplitude of the wide surface of the electrode assembly is large, the buffer sheet is arranged between the wide surface of the battery shell and the electrode assembly, and the expansion force of the electrode assembly can be effectively absorbed.

Furthermore, the buffer sheet is formed by compounding any one or more than two of the following materials: nitrile rubber, silicone rubber, fluorine resin and polypropylene.

In the technical scheme, the buffer sheet is made of the materials, so that the buffer sheet can be guaranteed to have better elasticity and compression deformation range.

Furthermore, the thickness of the buffer sheet is 1 mm-10 mm.

In the technical scheme, the buffer sheet with the thickness of 1-10 mm can effectively absorb the expansion force of the electrode assembly, and meanwhile, the volume of the battery monomer cannot be obviously increased.

Further, the compression deformation range of the buffer sheet is 5-65%.

In the technical scheme, the compression deformation range of the buffer sheet is large, and the expansion force of the electrode assembly can be effectively absorbed.

Further, the buffer sheet can bear a compressive strength less than the rupture strength of the battery case.

In the technical scheme, the compression strength of the buffer sheet is smaller than the rupture strength value of the battery shell, so that the expansion force of the electrode assembly can be effectively absorbed by the single battery buffer sheet within the bearable compression strength range, and the battery shell can be prevented from deforming or rupturing.

In order to solve the above technical problem, the present application further provides another technical solution:

a battery pack, comprising: the battery box comprises a box body and more than two battery monomers, wherein the battery monomers are arranged in the box body and are in any technical scheme.

In the technical scheme, the buffer sheet is arranged between the battery shell and the electrode assembly, the buffer sheet is made of elastic materials, the expansion force of the electrode assembly can be effectively absorbed, the internal pressure of the battery monomer is reduced, and the buffer sheet is provided with a plurality of holes which can contain gas generated by the electrode assembly, so that the internal pressure of the battery monomer is further reduced.

an electric device comprises a battery cell according to any one of the above technical schemes, wherein the battery cell is used for providing electric energy.

Be different from prior art, above-mentioned technical scheme provides battery monomer, is equipped with the buffer sheet between battery case and electrode subassembly, and the buffer sheet is made by elastic material, can effectively absorb electrode subassembly's bulging force, reduces battery monomer internal pressure to be provided with a plurality of holes on the buffer sheet, the hole can hold the produced gas of electrode subassembly, thereby further reduce the inside pressure of battery monomer.

Drawings

Fig. 1 is a schematic structural diagram of an electrical device according to an embodiment of the present application;

fig. 2 is a schematic structural diagram of a battery pack according to an embodiment of the present application;

fig. 3 is a schematic structural diagram of the battery module according to an embodiment of the present disclosure;

fig. 4 is a schematic structural diagram of a battery cell according to an embodiment of the present disclosure;

FIG. 5 isbase:Sub>A cross-sectional view taken along line A-A of FIG. 4;

FIG. 6 is a cross-sectional view of the electrode assembly in an embodiment of the present application;

FIG. 7 is a cross-sectional view of the electrode assembly in an embodiment of the present application;

FIG. 8 is a schematic structural diagram of the buffer sheet according to an embodiment of the present application;

FIG. 9 is a cross-sectional view taken along line B-B of FIG. 8;

fig. 10 is a partially enlarged view of a portion a in fig. 9.

Description of reference numerals:

100. a controller;

200. a battery pack;

300. a motor;

21. a battery module; 211. an end plate; 212. a side plate;

22. a lower housing;

23. an upper housing;

1. a battery cell;

11. a battery case; 111. wide surface; 112. narrow sides;

12. an end cap; 121. a liquid injection hole; 122. an explosion-proof valve;

13. an electrode assembly; 131. a first pole piece; 132. a diaphragm; 133. a second pole piece;

14. an electrode terminal;

15. a buffer sheet; 151. a solid portion; 152. a hole; 153. a unidirectional breathable film; 154. an opening;

Detailed Description

Embodiments of the present application will be described in further detail below with reference to the drawings and examples. The following detailed description of the embodiments and the accompanying drawings are provided to illustrate the principles of the application and are not intended to limit the scope of the application, i.e., the application is not limited to the described embodiments. In the description of the present application, it is to be noted that, unless otherwise specified, "a plurality" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," and the like, indicate an orientation or positional relationship that is merely for convenience in describing the application and to simplify the description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the application. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. "vertical" is not strictly vertical, but is within the tolerance of the error. "parallel" is not strictly parallel but within the tolerance of the error.

In the description of the present application, it is also to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; may be directly connected or indirectly connected through an intermediate. The specific meaning of the above terms in the present application can be understood as appropriate by one of ordinary skill in the art.

In the prior art, when the secondary battery is charged and discharged, the battery case is expanded along with the expansion of the electrode assembly due to the electrochemical reaction. In the prior art, an elastic plate is mainly arranged outside a battery shell to absorb the expansion force of a battery cell. The prior art can absorb stress generated by the expansion of the electrode assembly to a certain extent, but the effect is still very limited, and the thickness of the elastic plate is large, so that the volume of the battery module is increased, and the energy density of the battery module is reduced.

And the applicant has studied to notice that the reason for the expansion of the battery cell case is partly due to the gassing of the electrolyte in addition to the volume expansion of the electrode assembly. For lithium metal batteries, particularly, three-dimensional metal foam materials are used as the negative electrode, and the gas production rate of the electrolyte is relatively high, so that the problem of gas production in the battery needs to be properly solved in addition to the problem of volume change of an electrode assembly caused by charging and discharging, so as to avoid the influence on the interface of a pole piece to deteriorate the battery performance.

In order to improve the quality of welding of the sealing nail at the liquid injection hole, the applicant provides a single battery, wherein a buffer sheet is arranged between a battery shell and an electrode assembly, the buffer sheet is made of an elastic material and can effectively absorb the expansion force of the electrode assembly, a plurality of holes are formed in the buffer sheet, and the holes in the buffer sheet can absorb gas generated by the content of the single battery, so that the pressure of the content of the single battery is reduced, and the expansion force of the single battery is further reduced.

Based on the above problems discovered by the applicant, the applicant has improved the battery cell, and the following further describes the embodiments of the present application.

The embodiment of the present application provides an electric device using a battery pack 200 as a power source. The electric device can be, but is not limited to, a vehicle, a ship, an aircraft or the like. As shown in fig. 1, a battery pack 200 may be used to power a vehicle, and a plurality of battery modules 21 are provided in the battery pack 200. The vehicle can be a fuel automobile, a gas automobile or a new energy automobile. The new energy automobile can be a pure electric automobile, a hybrid electric automobile or a range-extended automobile and the like. In an embodiment of the present application, a vehicle may include a motor 300, a controller 100, and a battery pack 200. The controller 100 is used to control the battery pack 200 to supply power to the motor 300. The motor 300 is connected to the wheels through a transmission mechanism, thereby driving the vehicle to travel. The battery pack 200 may be used as a driving power source for a vehicle instead of or in part instead of fuel or natural gas to provide driving power for the vehicle. In one example, the battery pack 200 may be provided at the bottom or the front or rear of the vehicle. The battery pack 200 may be used to power a vehicle.

As shown in fig. 2, the present embodiment provides a battery pack 200, a plurality of battery modules 21 are disposed in the battery pack 200, and as shown in fig. 3, a plurality of battery cells 1 are disposed in the battery modules 21. The battery pack 200 includes a case, and the shape of the case is not limited. The box body can be a frame-shaped box body, a disc-shaped box body or a box-shaped box body and the like. Illustratively, the case includes a lower case 22 and an upper case 23 covering the lower case 22. The upper shell 23 and the lower shell 22 are covered to form a containing part, and the upper shell 23 and the lower shell 22 are locked and fixed through fasteners such as bolts and the like after being covered. As shown in fig. 2, a plurality of battery modules 21 are provided in the battery pack 200, and the battery modules 21 are provided in the housing portion of the case. The battery module 21 includes a plurality of battery cells 1, and the plurality of battery cells 1 may be electrically connected in series or in parallel or in series-parallel.

As shown in fig. 3, in an embodiment, the battery module 21 includes a plurality of battery cells 1, end plates 211, and side plates 212, wherein each of the end plates 211 and the side plates 212 has two, the two end plates 211 and the two side plates 212 form a rectangular module frame, and the plurality of battery cells 1 are arranged in the module frame. Wherein the battery module 21 has a predetermined height, width and length. The battery cell 1 is a rechargeable secondary battery. The arrangement direction of two or more battery cells 1 is the same as the longitudinal direction of the battery module 21. A module frame surrounded by the end plates 211 and the side plates 212 is fitted around each battery cell 1 to fix each battery cell 1. The two end plates 211 are disposed opposite to each other along the arrangement direction of the battery cells 1, and each battery cell 1 is disposed between the two end plates 211. The two side plates 212 are disposed on both sides of each battery cell 1 in the width direction. The end portions of the end plates 211 are fixedly connected with the end portions of the side plates 212, wherein the end portions of the end plates 211 and the end portions of the side plates 212 can be fixedly connected by welding, gluing or fasteners such as bolts and rivets. The side plates 212 and the end plates 211 can be made of metal or alloy such as aluminum and aluminum alloy, the side plates 212 and the end plates 211 can be of an integrated structure, the structural strength of the side plates is high, and the bearing stress performance is good.

As shown in fig. 3, the battery cell 1 has a wide face and a narrow face. The respective wide surfaces of two adjacent single batteries 1 are arranged opposite to each other, and the end plate 211 is arranged corresponding to the wide surface of the single battery 1. The wide surfaces of two adjacent single batteries 1 are fixedly connected through glue. The two side plates 212 are arranged corresponding to the narrow surfaces of the battery cells 1, and the narrow surfaces of the battery cells 1 are fixedly connected with the side plates 212 through glue. When the battery module is assembled, glue is coated on the wide surfaces of the battery monomers 1, glue is coated on the narrow surfaces of the battery monomers 1, then the battery monomers 1 are arranged in a module frame surrounded by the side plates 212 and the end plates 211, the wide surfaces of the battery monomers 1 are bonded through the glue, and the narrow surfaces of the battery monomers 1 are bonded with the side plates 212.

As shown in fig. 4, in the battery cell 1 provided for one embodiment, the battery cell 1 includes a battery case 11, an end cap 12, and an electrode assembly 13 disposed in the battery case 11. The battery case 11 is an assembly for mating with the end cap 12 to form an internal environment of the battery cell 1, wherein the formed internal environment may be used to house the electrode assembly 13, electrolyte, and other components. The battery case 11 may have a rectangular parallelepiped structure or other structures.

As shown in fig. 5, the electrode assembly 13 is disposed inside the battery case 11, the battery case 11 has an inner space for accommodating the electrode assembly 13 and the electrolyte, the battery case 11 and the end cap 12 may be separate components, and an opening may be formed in the battery case 11, and the opening is covered by the end cap 12 at the opening to form the internal environment of the battery cell 1. Without limitation, the end cap 12 and the battery case 11 may be integrated, and specifically, the end cap 12 and the battery case 11 may form a common connecting surface before other components are inserted into the case, and when it is necessary to enclose the inside of the battery case 11, the end cap 12 covers the battery case 11. The battery case 11 may have various shapes and various sizes, such as a rectangular parallelepiped shape, a cylindrical shape, a hexagonal prism shape, and the like. Specifically, the shape of the battery case 11 may be determined according to the specific shape and size of the electrode assembly 13. The material of the battery case 11 may be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiment of the present invention is not limited thereto.

The end cap 12 is provided with a liquid injection hole 121, an explosion-proof valve 122 and two electrode terminals 14, wherein one electrode terminal 14 is a positive electrode terminal, and the other electrode terminal 14 is a negative electrode terminal. The end cap 12 may be made of a material (e.g., aluminum alloy) having a certain hardness and strength, so that the end cap 12 is not easily deformed when being extruded and collided, and the battery cell 1 may have a higher structural strength and an improved safety performance.

The electrode assembly 13 is a component of the battery cell 1 where electrochemical reactions occur. One or more electrode assemblies 13 may be contained within the battery case 11.

As shown in fig. 6 and 7, the electrode assembly 13 may be formed by stacking or winding a first pole piece 131, a second pole piece 133, and a separator 132 together, wherein the separator 132 is an insulator interposed between the first pole piece 131 and the second pole piece 133. FIG. 6 is a schematic view of a wound electrode assembly; fig. 7 is a schematic view of a stacked electrode assembly.

In this embodiment, the first tab 131 is exemplarily described as a positive electrode tab, and the second tab 133 is exemplarily described as a negative electrode tab. Both the positive electrode tab and the negative electrode tab include a coated region and an uncoated region. The positive electrode tab active material is coated on the coating region of the positive electrode tab, and the negative electrode tab active material is coated on the coating region of the negative electrode tab. On the coated region, the active material is coated on a current collector formed of a metal thin plate, and on the uncoated region, the active material is not coated. The uncoated region of the positive electrode sheet forms the positive electrode tab, and the uncoated region of the negative electrode sheet forms the negative electrode tab. The electrode assembly 13 includes a main body portion, a positive electrode tab and a negative electrode tab, the positive electrode tab and the negative electrode tab are respectively formed by extending from one end portion of the main body portion, the positive electrode tab is connected to one of the electrode terminals 14 through a conductive connecting member, and the negative electrode tab is connected to the other electrode terminal 14 through another conductive connecting member. The positive electrode tab and the negative electrode tab can be positioned at one end of the main body part or can be respectively positioned at two ends of the main body part. The electrode assembly 13 is a component of the battery cell 1 where electrochemical reactions occur. During the charge and discharge of the battery, the positive and negative active materials react with the electrolyte, and the tab 23a is connected to the electrode terminal to form a current loop.

Referring to fig. 4 and 5, in the above embodiment, the single battery further includes a buffer sheet 15, the buffer sheet 15 is disposed between the battery case 11 and the electrode assembly 13, the buffer sheet 15 is made of an elastic material, and the buffer sheet is provided with a plurality of holes 152.

Wherein the buffer sheet 15 is disposed between the battery case 11 and the electrode assembly 13, and the buffer sheet 15 has a certain thickness and is elastically compressible and resilient in a thickness direction. One side of the buffer sheet 15 is in contact with the battery case 11, and the other side of the buffer sheet 15 is in contact with the electrode assembly 13. The holes 152 of the buffer sheet 15 may be formed by partially hollowing out the buffer sheet 15, and the shape of the holes 152 may be circular, square, triangular or polygonal.

When the electrode assembly 13 expands, the buffer sheet 15 elastically contracts to absorb the expansion force of the electrode assembly 13, and when the electrode assembly 13 contracts, the buffer sheet 15 rebounds and restores the original thickness. And a plurality of holes 152 are formed in the buffer sheet 15, and the holes 152 can absorb gas generated inside the battery cells, thereby reducing the gas pressure inside the battery cells.

The buffer sheet 15 may be made of any one of the following materials or a combination of two or more of the following materials: nitrile rubber, silicone rubber, fluorine resin and polypropylene.

The nitrile rubber, the silicone rubber, the fluorine resin, the polypropylene and the composite material thereof have good chemical stability, do not react with the battery electrolyte, have good elasticity and compression deformation range, and can ensure that the buffer sheet 15 can fully absorb the expansive force of the electrode assembly 13.

In the embodiment, the thickness of the buffer sheet 15 is 1mm to 10mm. Among them, the thickness of the buffer sheet 15 may be determined according to the size, chemical composition, etc. of the electrode assembly 13 and the expansion deformation amplitude thereof, and when the size of the electrode assembly 13 is large, the expansion deformation amplitude thereof is correspondingly large, and therefore, the thickness of the buffer sheet 15 should be appropriately increased in this case; and when the expansion deformation amplitude of the electrode assembly 13 is small, the thickness of the buffer sheet 15 can be reduced accordingly. In the embodiment, the thickness of the buffer sheet 15 is 1mm to 10mm, so that the expansion force of the electrode assembly 13 can be effectively absorbed, and the volume of the battery cell 1 is not significantly increased, thereby ensuring the energy density of the battery cell.

In the examples, the compression set range of the cushion sheet 15 is 5% to 65%. The compression deformation range is a ratio of a maximum deformation amount that the cushion sheet 15 can withstand to an initial state under the condition of elastic deformation. In the above embodiment, the compression set range of the buffer sheet 15 is large, and the expansion force of the electrode assembly 13 can be effectively absorbed.

In the above embodiment, the buffer sheet 15 can withstand a compression strength smaller than the rupture strength of the battery case 11. The compressive strength of the cushion sheet 15 refers to the maximum pressure or pressure that the cushion sheet 15 can withstand before crushing. The rupture strength value of the battery case 11 refers to a pressure or a pressure that the battery case 11 can withstand when ruptured.

In some embodiments, the buffer sheet 15 can withstand a compressive strength of 0.3 MPa.ltoreq.sigma.ltoreq.15 MPa, sigma always being smaller than the rupture strength of the battery case. It should be noted that the compressive strength σ that the buffer sheet 15 can bear is always smaller than the rupture strength of the battery case 11, and it is ensured that the volume of the buffer sheet 15 is contracted when the buffer sheet 15 receives the expansion stress from the electrode assembly 13, so as to absorb the expansion force of the electrode assembly and prevent the battery case 11 from being deformed by the expansion force of the electrode assembly.

As shown in fig. 4 and 5, the battery case 11 has a rectangular case, the battery case 11 includes a wide face 111 and a narrow face 112, and the buffer sheet 15 is disposed between the wide face 111 and the electrode assembly 13. Wherein the battery case 11 includes two wide surfaces 111 and two narrow surfaces 112, wherein the area of the wide surface 111 is larger than that of the narrow surface 112, and accordingly, the electrode assembly 13 also has the wide surface and the narrow surface, and the wide surface of the electrode assembly 13 is opposite to the wide surface 111 of the battery case 11, the narrow surface of the electrode assembly 13 is opposite to the narrow surface 112 of the battery case 11, and the buffer sheet 15 is located between the wide surface 111 of the battery case 11 and the wide surface of the electrode assembly 13.

Since the expansion force of the electrode assembly 13 is mainly applied to the wide surface 111 of the battery case 11 when the electrode assembly is expanded, in the above embodiment, the buffer sheet 15 is disposed between the wide surface 111 of the battery case 11 and the electrode assembly, the buffer sheet 15 can absorb most of the expansion force of the electrode assembly 13, and the buffer sheet 15 does not occupy the space where the narrow surface 112 is located in the battery unit, so that the expansion force of the electrode assembly 13 can be absorbed, and the energy density of the battery unit can be ensured.

As shown in fig. 8, in one embodiment, two or more rows of holes 152 are formed on the buffer sheet 15, and each row has two or more holes 152. Each row of holes 152 may be arranged on the buffer sheet 15 along the height direction of the battery cell, or along the width direction of the battery cell. A certain interval is provided between two adjacent rows of holes 152, the area between two adjacent rows of holes 152 is a solid portion 151, and the area on the buffer sheet 15 having the holes 152 is a hollow portion. In this embodiment, the buffer sheet 15 is formed with a hollow portion having holes 152 and a solid portion 151 having no holes, wherein the solid portion 151 has high elasticity, so that the buffer sheet 15 can effectively absorb gas generated inside the battery cell and the solid portion 151 can provide sufficient elastic supporting force for the electrode assembly 13.

Of course, in other embodiments, the holes 152 on the buffer sheet 15 may also be uniformly distributed on the buffer sheet 15.

Referring to fig. 9 and 10, in one embodiment, the cavity 152 is a bladder-shaped cavity structure having an opening 154, and the opening 154 is located on the surface of the cushion sheet 15. One end of the hole 152 in the thickness direction of the buffer sheet 15 is sealed, the other end of the hole 152 is an opening 154, and gas generated inside the battery cell 1 can enter the hole 152 through the opening 154. In this embodiment, the holes 152 are equal-diameter holes, that is, the hole diameters of the holes 152 are not changed at different positions along the thickness direction of the buffer sheet 15, and the equal-diameter holes are convenient for processing and production, so that the production efficiency of the buffer sheet 15 can be ensured and the production process can be simplified. In other embodiments, the holes 152 may be expanded holes, i.e., the inner diameter of the holes 152 is larger than the diameter of the openings 154, and the volume of the expanded holes is larger than that of the holes with the same diameter, so as to increase the gas absorption capacity of the holes 152.

As shown in fig. 10, in an embodiment, a one-way air permeable membrane 153 is further disposed at the opening 154 of the hole 152, and an air inlet direction of the one-way air permeable membrane 153 is directed from outside the hole 152 to inside the hole 152. The unidirectional air-permeable membrane 153 is made of a waterproof polymer material, has waterproof and unidirectional air-permeable functions, prevents liquid from permeating therethrough, and allows gas to pass therethrough only in a single direction. In this embodiment, the one-way air-permeable film 153 with a larger area may be used to cover the surface of the buffer sheet 15 having the openings 154, so that one-way air-permeable film 153 may cover all the openings 154 on the buffer sheet 15, thereby improving the convenience of construction of the one-way air-permeable film 153. In other embodiments, each row of holes 152 may also be covered by one unidirectional air permeable membrane 153, such that the unidirectional air permeable membrane 153 covers all the holes 152 in the row. In other embodiments, a single air permeable membrane 153 may be disposed over each hole 152.

In the above embodiment, the one-way gas permeable membrane 153 is disposed on the opening 154 of the void 152, and the one-way gas permeable membrane 153 only allows gas to enter the void 152, and the gas in the void 152 cannot return to the outside of the void 152, thereby ensuring stable gas pressure inside the battery cell.

It should be noted that, although the above embodiments have been described herein, the scope of the present invention is not limited thereby. Therefore, based on the innovative idea of the present invention, the changes and modifications to the embodiments herein, or the equivalent structures or equivalent flow changes made by the contents of the specification and the drawings of the present invention, directly or indirectly apply the above technical solutions to other related technical fields, all included in the scope of the present invention.

Claims

1. A battery cell, comprising:

a battery case;

the battery comprises a battery shell, an electrode assembly and a control circuit, wherein the electrode assembly is arranged in the battery shell and comprises a positive plate, a negative plate and an isolating membrane, and the isolating membrane is arranged between the positive plate and the negative plate; and

the buffer sheet is arranged between the battery shell and the electrode assembly and is made of elastic materials, and a plurality of holes are formed in the buffer sheet.

2. The battery cell as claimed in claim 1, wherein two or more rows of the holes are spaced apart from each other on the buffer sheet, and each row has two or more holes.

3. The battery cell as claimed in claim 1, wherein the cavity is a capsule-shaped cavity structure having an opening, and the opening is located on the surface of the buffer sheet.

4. The battery cell as recited in claim 3, wherein the opening is provided with a one-way gas permeable membrane, and a gas inlet direction of the one-way gas permeable membrane is directed from outside the hole to inside the hole.

5. The battery cell of any of claims 1-4, wherein the battery housing comprises a broad face and a narrow face; the buffer sheet is disposed between the wide surface and the electrode assembly.

6. The battery cell according to any one of claims 1 to 4, wherein the buffer sheet is formed of any one of the following materials: nitrile rubber, silicone rubber, fluorine resin and polypropylene.

7. The battery cell according to claim 1, wherein the thickness of the buffer sheet is 1mm to 10mm.

8. The battery cell according to claim 1, wherein the buffer sheet has a compression set in a range of 5% to 65%.

9. The battery cell as recited in claim 1, wherein the buffer sheet can withstand a compressive strength that is less than a burst strength value of the battery case.

10. A battery pack, comprising: the battery pack comprises a box body and more than two battery monomers, wherein the battery monomers are arranged in the box body, and the battery monomers are the battery monomers in any one of claims 1 to 9.

11. An electric device, characterized in that the electric device comprises a battery cell according to any one of claims 1 to 9 for providing electric energy.