Battery and electric device including same

Abstract

A battery and an electric device including same. The battery comprises an electrode assembly, a housing accommodating the electrode assembly, and a first layer including an insulating material. The electrode assembly comprises a first electrode sheet and a second electrode sheet, which are stacked in a fourth direction and are arranged adjacently. The first electrode sheet comprises a first edge extending in a first direction, a second edge extending in a second direction perpendicular to the first direction, and a third edge extending in a third direction intersecting both the first direction and the second direction, wherein the third edge comprises a first end connected to the first edge and a second end connected to the second edge. The first layer is bonded to the first electrode sheet, and comprises a first edge extending in the first direction, and a second edge that extends in the second direction and is connected to the first edge. When viewed in the fourth direction, the first edge and the second edge each comprise a portion overlapping with the first electrode sheet, and the first edge further comprises a portion that is separated from the first edge and the second edge and connected to the third edge. In the fourth direction, the first electrode sheet is located on the outermost side of the electrode assembly.

Description

Batteries and electrical equipment containing them Technical Field

[0001] The present application relates to the field of energy storage devices, and in particular to a battery and an electrical device containing the same. Background Art

[0002] Currently, battery cells are primarily manufactured through lamination and winding processes. These cells are widely used due to their numerous advantages, such as high rate capability and high energy density. However, during the production process, the edges or corners of the battery cell's electrodes may curl or warp.

[0003] Summary of the Invention

[0004] One purpose of the present application is to provide a battery that can reduce the risk of curling and warping of pole pieces.

[0005] In a first aspect, the present application provides a battery comprising an electrode assembly, a housing for accommodating the electrode assembly, and a first layer comprising an insulating material. The electrode assembly comprises a first electrode sheet and a second electrode sheet stacked and adjacently arranged. The first electrode sheet comprises a first side extending along a first direction, a second side extending along a second direction perpendicular to the first direction, and a third side extending along a third direction intersecting both the first and second directions, the third side comprising a first end connected to the first side and a second end connected to the second side. The first layer is bonded to the first electrode sheet and comprises a first edge extending along the first direction and a second edge extending along the second direction and connected to the first edge. When viewed along a fourth direction perpendicular to both the first and second directions, the first edge and the second edge both comprise a portion overlapping the first electrode sheet, and the first edge further comprises a portion separated from the first and second sides and connected to the third side. The fourth direction is the direction in which the first and second electrode sheets are stacked, and in the fourth direction, the first electrode sheet is located at the outermost layer of the electrode assembly.

[0006] The first electrode of the present application is provided with a third side connected to the first side and the second side extending in directions perpendicular to each other, thereby increasing the contact area between the corner of the first electrode and the shell, reducing the impact force of the corner of the electrode assembly on the shell, and thus reducing the risk of the shell cracking and leaking due to the impact of the electrode assembly. Moreover, the first layer is provided with a first edge and a second edge, both of which include a portion overlapping with the first electrode, and the first edge also includes a portion separated from the first edge and the second edge and connected to the third edge, so that the first layer is bound in the fourth direction. The third side constituting the corner of the first electrode is reduced. The risk of the corner where the third side of the first electrode is located curling or warping during the production process is reduced. Therefore, the battery of the present application reduces the risk of the shell cracking and leaking due to the impact of the electrode assembly while reducing the risk of the corner of the first electrode curling or warping.

[0007] In one possible implementation, in the second direction, the first distance from the first end to the first edge is smaller than the second distance from the second end to the first edge, thereby increasing the contact area between the first layer and the third edge and further reducing the risk of curling or warping of the corner where the third edge of the first pole piece is located.

[0008] In a possible implementation, in the first direction, a third distance from the first end to the second edge is greater than a fourth distance from the first end to the second end.

[0009] In a possible implementation, the first edge and the third side are connected at a first intersection, and in the first direction, a fifth distance from the first end to the first intersection is smaller than a sixth distance from the second end to the first intersection.

[0010] In one possible implementation, the first pole piece further includes a fourth side extending along the first direction and opposite to the first side in the second direction, and a fifth side extending along a fifth direction intersecting both the first and second directions and different from the third direction, and connected to the third and fourth sides. The first layer further includes a third edge extending along the first direction and opposite to the first edge in the second direction; when viewed along the fourth direction, the third edge includes a portion overlapping with the first pole piece and a portion separated from the second and fourth sides and connected to the fifth side. The first layer is configured in this manner so that the first layer constrains the fifth side constituting the corner of the first pole piece in the fourth direction, reducing the risk of curling or warping of the corner of the first pole piece where the fifth side is located.

[0011] In one possible implementation, when viewed along the fourth direction, the second electrode sheet includes a first exposed portion exposed from the first electrode sheet, so that the area of ​​the second electrode sheet is larger than that of the first electrode sheet, thereby reducing the risk of lithium plating at the negative electrode.

[0012] In one possible implementation, when viewed along the fourth direction, the first layer also includes a portion overlapping with the first exposed portion, thereby increasing the contact area between the first layer and the electrode assembly, thereby increasing the bonding force between the first layer and the electrode assembly and reducing the risk of the first layer falling off.

[0013] In one possible implementation, the electrode assembly also includes an isolation membrane arranged between the first pole piece and the second pole piece. When viewed along the fourth direction, the isolation membrane includes a second exposed portion exposed from the first pole piece and the second pole piece, so that the area of ​​the isolation membrane is larger than the area of ​​the first pole piece and the second pole piece, thereby reducing the risk of short circuit between the first pole piece and the second pole piece.

[0014] In a possible implementation manner, when viewed along the fourth direction, the first layer further includes a portion overlapping with the second exposed portion.

[0015] In one possible implementation, the electrode assembly further includes a first surface and a second surface opposite to each other in the fourth direction and a first end surface connected between the first surface and the second surface, and the first layer is bonded to the first surface, the first end surface, and the second surface.

[0016] In a possible implementation, the first electrode is a positive electrode, and the second electrode is a negative electrode.

[0017] In a possible implementation, the first layer is single-sided tape or double-sided tape.

[0018] In one possible implementation, the electrochemical device also includes a first metal plate and a second metal plate, the first metal plate is electrically connected to the first electrode sheet and extends out of the shell in a first direction, and the second metal plate is electrically connected to the second electrode sheet and extends out of the shell in the first direction; in the first direction, the first metal plate and the first layer are located on opposite sides of the electrode assembly, and the second metal plate and the first layer are located on opposite sides of the electrode assembly.

[0019] In a possible implementation, the shell is a packaging bag.

[0020] In a possible implementation, the outer surface of the first pole piece is a hollow foil area.

[0021] The second aspect of the present application further provides an electrical device comprising any of the above-mentioned batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0023] FIG1 is a fourth direction view of a battery provided in one embodiment of the present application;

[0024] FIG2 is a fourth direction view of the electrode assembly provided by one embodiment of the present application from the first surface;

[0025] FIG3 is a fourth direction view of the electrode assembly provided by one embodiment of the present application from the second surface;

[0026] FIG4 is a cross-sectional view of the electrode assembly shown in FIG2 along line IV-IV;

[0027] FIG5 is a schematic structural diagram of an electrical device provided in one embodiment of the present application.

[0028] Description of Main Component Symbols Battery 100 Housing 10 Electrode Assembly 20 First Metal Plate 40 Second Metal Plate 50 Main Body 11 Packaging 12 Separator 23 First Pole Sheet 21 Second Pole Sheet 22 First Current Collector 211 First Active Material Layer 212 First Tab 213 Second Current Collector 221 Second Active Material Layer 222 Second Tab 223 First Surface 201 Second Surface 202 First End 203 Second End 204 First Layer 30 First Side 21a Second Side 21b Third Side 21c Fourth Side 21d Fifth Side 21e Sixth Side 21f First Edge 30a Second Edge 30b Third Edge 30c First End A1 Second End A2 Third EndA3 fourth end A4 first distance D1 second distance D2 third distance D3 fourth distance D4 fifth distance D5 sixth distance D6 seventh distance D7 eighth distance D8 ninth distance D9 tenth distance D10 eleventh distance D11 twelfth distance D12 first intersection O second intersection O' first exposed portion 22a second exposed portion 23a electrical device 1 first direction X second direction Y third direction XY fourth direction Z fifth direction YX DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application are described clearly and in detail below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present application. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0030] Below, embodiments of the present application will be described in detail. However, the present application may be embodied in many different forms and should not be construed as limited to the exemplary embodiments illustrated herein. Rather, these exemplary embodiments are provided to make the present application thorough and detailed for those skilled in the art.

[0031] In addition, for the sake of brevity and clarity, the size or thickness of various components, layers may be exaggerated in the accompanying drawings. Throughout the text, the same numerical value refers to the same element. In addition, it should be understood that when element A is referred to as being "connected to" element B, element A may be directly connected to element B, or there may be an intermediate element C and element A and element B may be indirectly connected to each other.

[0032] Further, when describing embodiments of the present application, the use of “may” refers to “one or more embodiments of the present application.”

[0033] The professional terms used herein are for the purpose of describing specific embodiments and are not intended to limit the application. As used herein, the singular form is intended to also include the plural form, unless the context clearly indicates otherwise. It should be understood that the term "comprising", when used in this specification, refers to the presence of narrated features, numerical values, steps, operations, elements and / or components, but does not exclude the presence or increase of one or more other features, numerical values, steps, operations, elements, components and / or combinations thereof. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts herein, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are used to distinguish an element, component, region, layer or part from another element, component, region, layer or part. Therefore, the first element, component, region, layer or part discussed below can be referred to as the second element, component, region, layer or part, without departing from the teaching of exemplary embodiments.

[0034] Referring to Figures 1 to 4 , one embodiment of the present application provides a battery 100 comprising a housing 10, an electrode assembly 20 and an electrolyte contained within the housing 10, and a first metal plate 40 and a second metal plate 50. The first metal plate 40 and the second metal plate 50 are respectively electrically connected to the electrode assembly 20 and extend from the housing 10 to connect to external components (not shown). Figures 2 to 4 illustrate that the battery 100 includes a single electrode assembly 20. In other embodiments, the battery 100 may include multiple electrode assemblies 20 to achieve a high voltage output.

[0035] The housing 10 can be a packaging bag encapsulated with an encapsulating film, i.e., the battery 100 is a soft-pack battery. Specifically, the housing includes a main body 11 and an encapsulating portion 12. The main body 11 defines a cavity for accommodating the electrode assembly 20. The encapsulating portion 12 extends from the edge of the main body 11 and serves to seal the main body 11. In other embodiments, the housing 10 is a metal housing, such as steel or aluminum.

[0036] As shown in FIG4 , the electrode assembly 20 includes a first electrode piece 21 and a second electrode piece 22, and an isolation film 23 disposed between the first electrode piece 21 and the second electrode piece 22. In this embodiment, the first electrode piece 21, the isolation film 23, and the second electrode piece 22 are alternately stacked in the fourth direction Z to form a laminated structure. The isolation film 23 is used to reduce the risk of a short circuit caused by direct contact between the first electrode piece 21 and the second electrode piece 22. In some embodiments, the isolation film 23 includes at least one of the following polymers: polyolefin, polyvinylidene fluoride, polyethylene terephthalate, cellulose, polyimide, polyamide, spandex, and polyphenylene phthalate.

[0037] The first electrode sheet 21 includes a first current collector 211, a first active material layer 212, and a first electrode tab 213. The first active material layer 212 is disposed on at least one surface of the first current collector 211, and the first electrode tab 213 electrically connects the first metal plate 40 and the first current collector 211. The second electrode sheet 22 includes a second current collector 221, a second active material layer 222, and a second electrode tab 223. The second active material layer 222 is disposed on at least one surface of the second current collector 221, and the second electrode tab 223 electrically connects the second metal plate 50 and the second current collector 221. In this embodiment, the first electrode tab 213 extends outward from one end of the first current collector 211 away from the first active material layer 212, and the second electrode tab 223 extends outward from one end of the second current collector 221 away from the second active material layer 222. The first electrode tab 213 can be welded to the area where the first current collector 211 leaves the second active material layer 222 , and the second electrode tab 223 can be welded to the area where the second current collector 221 leaves the second active material layer 222 , which is not limited in this application.

[0038] In some embodiments, the first electrode sheet 21 is a positive electrode sheet, and the second electrode sheet 22 is a negative electrode sheet. Specifically, the first current collector 211 includes at least one of Ni, Ti, Cu, Ag, Au, Pt, Fe, Al, and combinations thereof. The first active material layer 212 includes a positive electrode active material, which may include at least one of lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium nickel cobalt manganese oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium vanadium oxyphosphate, lithium-rich manganese-based materials, lithium nickel cobalt aluminum oxide, and combinations thereof. The second current collector 221 includes at least one of Ni, Ti, Cu, Ag, Au, Pt, Fe, Al, and combinations thereof. The second active material layer 222 includes a negative electrode active material, which may be selected from at least one of graphite materials, alloy materials, lithium metal, and alloys thereof. The graphite material may be selected from at least one of artificial graphite and natural graphite; the alloy material may be selected from at least one of silicon, silicon oxide, tin, and titanium sulfide.

[0039] Referring to FIG. 4 , the electrode assembly 20 further includes a first surface 201 and a second surface 202 that are opposed in a fourth direction Z, and a first end surface 203 and a second end surface 204 that are opposed in a first direction X. The first end surface 203 and the second end surface 204 are both connected between the first surface 201 and the second surface 202. Referring to FIG. 2 and FIG. 3 , the first electrode tab 213 and the second electrode tab 223 are disposed on the second end surface 204. The end surfaces of the first electrode piece 21, the second electrode piece 22, and the isolation film 23 that are located on opposite sides of the first electrode tab 213 and the second electrode tab 223 in the first direction X constitute the first end surface 203, and the end surfaces of the first electrode piece 21, the second electrode piece 22, and the isolation film 23 that are located on the side of the first electrode tab 213 and the second electrode tab 223 in the first direction X constitute the second end surface 204. In this embodiment, the outermost layer of the electrode assembly 20 in the fourth direction Z is the first electrode piece 21, that is, the first surface 201 is the surface of the outermost first electrode piece 21 located on one side of the fourth direction Z, and the second surface 202 is the surface of the outermost first electrode piece 21 located on the other side of the fourth direction Z. In other embodiments, the outermost layer of the electrode assembly 20 in the fourth direction Z may be the second electrode piece 22 and / or the isolation film 23, and this application is not limited thereto.

[0040] The battery 100 further includes a first layer 30 comprising an insulating material. The first layer 30 covers at least a portion of the first surface 201, at least a portion of the second surface 202, and the entire first end face 203. The first layer 30 is bonded to the first surface 201, the second surface 202, and the first end face 203. The first layer 30 constrains the electrode assembly 20 in the fourth direction Z. In some embodiments, the first layer 30 is a single-sided tape or a double-sided tape.

[0041] In some embodiments, both the separator 23 and the first layer 30 are adhesive. The separator 23 is bonded to the adjacent first and second electrode pieces 21 and 22, thereby constraining the electrode assembly 20 in the fourth direction Z. The first layer 30 is directly bonded to the first surface 201 and the second surface 202. The separator 23 and the first layer 30 can each include at least one of the following polymers: a copolymer of vinylidene fluoride and hexafluoropropylene, a copolymer of vinylidene fluoride and trichloroethylene, polymethyl methacrylate, polyacrylic acid, polyacrylate, polyacrylonitrile, polyvinyl pyrrolidone, polyvinyl acetate, an ethylene-vinyl acetate copolymer, polyimide, polyethylene oxide, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, sodium carboxymethyl cellulose, lithium carboxymethyl cellulose, acrylonitrile-styrene-butadiene copolymer, polyvinyl alcohol, polyvinyl ether, polytetrafluoroethylene, polyhexafluoropropylene, a styrene-butadiene copolymer, or polyvinylidene fluoride. These polymers are able to produce stronger bonds.

[0042] Referring to Figures 2 and 3, the first electrode plate 21 is generally sheet-shaped and includes a first side 21a extending along a first direction X, a second side 21b extending along a second direction Y, a third side 21c extending along a third direction XY intersecting both the first and second directions Y and connecting the first and second sides 21a, 21b, a fourth side 21d extending along the first direction X and opposite the first side 21a in the second direction Y, a fifth side 21e extending along a fifth direction YX intersecting both the first and second directions Y and different from the third direction XY and connecting the second and fourth sides 21b, and a sixth side 21f extending along the second direction Y and opposite the second side 21b in the first direction X. The first, second, and fourth directions Z are perpendicular to each other. A first electrode tab 213 extends from the sixth side 21f along the first direction X, and a second electrode tab 223 extends from an edge of the second electrode plate 22 located on one side of the sixth side 21f along the first direction X. The angle between the first side 21a and the third side 21c, and the angle between the second side 21b and the third side 21c are both obtuse angles. The angle between the second side 21b and the fifth side 21e, and the angle between the fourth side 21d and the fifth side 21e are both obtuse angles. The third side 21c and the fifth side 21e constitute the two corners of the first electrode plate 21. Compared with the situation where the second side 21b is directly connected to the first side 21a and the third side 21c to form the two corners of the first electrode plate 21, this embodiment configures the third side 21c and the fifth side 21e to form a corner, thereby increasing the area of ​​the corner of the first electrode plate 21, that is, the contact area between the corner of the first electrode plate 21 and the shell 10, thereby reducing the impact force of the corner of the electrode assembly 20 on the shell 10, thereby reducing the risk of cracking of the packaging portion 12 due to the impact of the electrode assembly 20, resulting in leakage.

[0043] In this embodiment, the electrode is formed by cutting. After the cutting process, the corners of the electrode are prone to curling and warping. The present application configures a first layer 30 to improve the curling and warping problems of the electrode caused by cutting. The present application is also applicable to the curling and warping problems caused by electrode pieces produced by other methods. The first layer 30 is fixed to the first electrode 21 and includes a first edge 30a extending along the first direction X, a second edge 30b extending along the second direction Y, and a third edge 30c extending along the first direction X and opposite to the first edge 30a in the second direction Y. The second edge 30b connects the first edge 30a and the third edge 30c. The first edge 30a and the first side 21a are located on the same side of the electrode assembly 20 in the second direction Y, and the third edge 30c and the fourth side 21d are located on the other side of the electrode assembly 20 in the second direction Y.

[0044] When viewed along the fourth direction Z, the first edge 30a and the second edge 30b both include portions overlapping the first pole piece 21. The first edge 30a also includes a portion separated from the first side 21a and the second side 21b and connected to the third side 21c. The first layer 30 is arranged in this manner so that the first layer 30 constrains the third side 21c, which constitutes the corner of the first pole piece 21, in the fourth direction Z, reducing the risk of curling or warping of the corner of the first pole piece 21 where the third side 21c is located.

[0045] In some embodiments, when viewed along the fourth direction Z, the third edge 30c includes a portion overlapping the first pole piece 21 and a portion separated from the second side 21b and the fourth side 21d and connected to the fifth side 21e. The first layer 30 is arranged in this manner so that the first layer 30 constrains the fifth side 21e forming the corner of the first pole piece 21 in the fourth direction Z, thereby reducing the risk of curling or warping of the corner of the first pole piece 21 where the fifth side 21e is located.

[0046] The third side 21c includes a first end A1 connected to the first side 21a and a second end A2 connected to the second side 21b. The fifth side 21e includes a third end A3 connected to the fourth side 21d and a fourth end A4 connected to the second side 21b. In the second direction Y, the first distance D1 from the first end A1 to the first edge 30a is less than the second distance D2 from the second end A2 to the first edge 30a, thereby increasing the contact area between the first layer 30 and the third side 21c, increasing the adhesion between the first layer 30 and the third side 21c, and further reducing the risk of curling or warping at the corner of the first electrode 21 where the third side 21c is located. In the second direction Y, the seventh distance D7 from the third end A3 to the third edge 30c is less than the eighth distance D8 from the fourth end A4 to the third edge 30c, thereby increasing the contact area between the first layer 30 and the fifth side 21e, and further reducing the risk of curling or warping at the corner of the first electrode 21 where the fifth side 21e is located.

[0047] In the first direction X, a third distance D3 from the first end A1 to the second edge 30b is greater than a fourth distance D4 from the first end A1 to the second end A2. In the first direction X, a ninth distance D9 from the third end A3 to the second edge 30b is greater than a tenth distance D10 from the third end A3 to the fourth end A4.

[0048] The first edge 30a and the third side 21c meet at a first intersection O, and the third edge 30c and the fifth side 21e meet at a second intersection O'. In the first direction X, a fifth distance D5 from the first end A1 to the first intersection O is less than a sixth distance D6 from the second end A2 to the first intersection O. In the first direction X, an eleventh distance D11 from the third end A3 to the second intersection O' is less than a twelfth distance D12 from the fourth end A4 to the second intersection O'.

[0049] Referring to Figures 2 and 3 , when viewed along the fourth direction Z, the second electrode sheet 22 includes a first exposed portion 22a that protrudes from the first electrode sheet 21. This makes the area of ​​the second electrode sheet 22 larger than that of the first electrode sheet 21, thereby reducing the risk of lithium plating at the negative electrode. When viewed along the fourth direction Z, the first layer 30 also includes a portion that overlaps with the first exposed portion 22a, thereby increasing the contact area between the first layer 30 and the electrode assembly 20, thereby increasing the bonding strength between the first layer 30 and the electrode assembly 20 and reducing the risk of the first layer 30 falling off.

[0050] Referring to Figures 2 and 3 , as viewed along the fourth direction Z, the isolation membrane 23 includes a second exposed portion 23a that extends from the first and second electrode sheets 21, 22. This allows the isolation membrane 23 to have a larger area than the first and second electrode sheets 21, 22, thereby reducing the risk of short circuits between the first and second electrode sheets 21, 22. As viewed along the fourth direction Z, the first layer 30 also includes a portion that overlaps with the second exposed portion 23a. As viewed along the fourth direction Z, the first edge 30a, as it extends away from the electrode assembly 20 along the first direction X, intersects successively with the third side 21c, the second exposed portion 23a, and the first exposed portion 22a. As the third edge 30c, as it extends away from the electrode assembly 20 along the first direction X, intersects successively with the fifth side 21e, the second exposed portion 23a, and the first exposed portion 22a.

[0051] Referring to FIG5 , an embodiment of the present application further provides an electric device 1, which includes the battery 100 described above. The electric device 1 of the present application may be, but is not limited to, a laptop computer, a pen-type computer, a mobile computer, an e-book player, a portable phone, a portable fax machine, a portable copier, a portable printer, a head-mounted stereo headset, a video recorder, an LCD TV, a portable cleaner, a portable CD player, a mini-disc, a transceiver, an electronic notepad, a calculator, a memory card, a portable recorder, a radio, a backup electronic source, a motor, a car, a motorcycle, a power-assisted bicycle, a bicycle, a lighting fixture, a toy, a game console, a clock, an electric tool, a flashlight, a camera, a large household battery, a lithium-ion capacitor, and the like.

[0052] The above disclosure is only a preferred embodiment of the present application, and certainly cannot be used to limit the present application. Therefore, equivalent changes made based on the present application are still within the scope covered by the present application.

Claims

1. A battery, comprising an electrode assembly and a shell for accommodating the electrode assembly, wherein the electrode assembly comprises a first electrode sheet and a second electrode sheet stacked and adjacently arranged, characterized in that: The first pole piece includes a first side extending along a first direction, a second side extending along a second direction perpendicular to the first direction, and a third side extending along a third direction intersecting both the first direction and the second direction, the third side including a first end connected to the first side and a second end connected to the second side; The battery further comprises a first layer comprising an insulating material and bonded to the first electrode sheet, the first layer comprising a first edge extending along the first direction and a second edge extending along the second direction and connected to the first edge; Observed along a fourth direction perpendicular to both the first direction and the second direction, the first edge and the second edge both include a portion overlapping with the first pole piece, and the first edge also includes a portion separated from the first edge and the second edge and connected to the third edge; The fourth direction is a direction in which the first pole sheet and the second pole sheet are stacked. In the fourth direction, the first pole sheet is located at the outermost side of the electrode assembly.

2. The battery according to claim 1, characterized in that In the second direction, a first distance from the first end to the first edge is smaller than a second distance from the second end to the first edge.

3. The battery according to claim 1, characterized in that In the first direction, a third distance from the first end to the second edge is greater than a fourth distance from the first end to the second end.

4. The battery according to claim 1, characterized in that The first edge is connected to the third side at a first intersection, and in the first direction, a fifth distance from the first end to the first intersection is smaller than a sixth distance from the second end to the first intersection.

5. The battery according to claim 1, characterized in that The first pole piece also includes a fourth edge extending along the first direction and opposite to the first edge in the second direction, and a fifth edge extending along a fifth direction intersecting both the first direction and the second direction and different from the third direction and connected to the third edge and the fourth edge. The first layer also includes a third edge extending along the first direction and opposite to the first edge in the second direction. When viewed along the fourth direction, the third edge includes a portion overlapping with the first pole piece and a portion separated from the second edge and the fourth edge and connected to the fifth edge.

6. The battery according to claim 1, characterized in that When viewed along the fourth direction, the second pole piece includes a first exposed portion exposed from the first pole piece.

7. The battery according to claim 6, characterized in that When viewed along the fourth direction, the first layer further includes a portion overlapping the first exposed portion.

8. The battery according to claim 1, characterized in that The electrode assembly further includes an isolation film disposed between the first pole piece and the second pole piece. When viewed along the fourth direction, the isolation film includes a second exposed portion exposed from the first pole piece and the second pole piece.

9. The battery according to claim 8, characterized in that When viewed along the fourth direction, the first layer further includes a portion overlapping the second exposed portion.

10. The battery according to claim 1, characterized in that The electrode assembly further includes a first surface and a second surface opposite to each other in the fourth direction and a first end surface connected between the first surface and the second surface, and the first layer is bonded to the first surface, the first end surface and the second surface.

11. The battery according to claim 1, characterized in that The first pole piece is a positive pole piece, and the second pole piece is a negative pole piece.

12. The battery according to claim 1, characterized in that The first layer is single-sided adhesive or double-sided adhesive.

13. The battery according to claim 1, characterized in that The electrochemical device also includes a first metal plate and a second metal plate, the first metal plate is electrically connected to the first pole piece and extends out of the shell along the first direction, and the second metal plate is electrically connected to the second pole piece and extends out of the shell along the first direction; in the first direction, the first metal plate and the first layer are located on opposite sides of the electrode assembly, and the second metal plate and the first layer are located on opposite sides of the electrode assembly.

14. The battery according to claim 1, characterized in that The shell is a packaging bag.

15. The battery according to claim 1, characterized in that In the first direction, the outer surface of the first pole piece is a hollow foil area.

16. An electrical equipment, characterized in that: A battery assembly comprising the battery assembly as claimed in any one of claims 1 to 15.

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