Battery cells and batteries

Abstract

This application provides a battery cell and a battery. The battery cell includes a casing with at least one open end; a cover plate body that covers the open end; and an insulating film that covers the casing. A portion of the insulating film extending beyond the cover plate body along its thickness direction is bent and fixed to the cover plate body, forming a folded edge. The folded edges are stacked along the thickness direction of the cover plate body in a portion of the cover plate body, forming a multi-layer structure. Adjacent folded edge layers in the multi-layer structure are interconnected. The battery cell and battery provided by this application, with their interconnected multi-layer folded edge layers, not only prevent problems such as warping, folding, or damage to the insulating film, but also ensure that structural components connected to the insulating film can form a reliable connection with the insulating film, thereby improving the appearance of the battery cell and ensuring good insulation performance.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to a battery cell and a battery. Background Technology

[0002] The battery cell includes a housing and a cover plate assembly that fits over the opening of the housing. To achieve insulation between the battery cell and the outside, an insulating film can be wrapped around the outside of the housing.

[0003] After the insulating film covers the casing, the portion extending beyond the casing opening can be bent towards the cover assembly and connected to the cover assembly with an adhesive surface to form a folded edge. However, the folded edge is prone to warping or damage, affecting the insulation performance of the cell and consequently impacting the battery's safety and lifespan. Utility Model Content

[0004] In view of this, the purpose of this application is to provide a battery cell and a battery to at least partially solve the problem that the appearance and insulation performance of the battery cell are affected by the curling of the edge of the insulating film.

[0005] To achieve the above objectives, the first aspect of this application provides a battery cell, comprising: a housing having at least one open end; a cover plate body covering the open end; and an insulating film covering the housing; wherein a portion of the insulating film extending beyond the cover plate body along the height direction of the battery cell is bent and fixed to the cover plate body, forming a folded edge; the folded edges are stacked in a portion of the cover plate body along the height direction of the battery cell to form a multi-layer structure, wherein adjacent layers of the folded edges in the multi-layer structure are interconnected.

[0006] Optionally, the insulating film has a first surface and a second surface disposed opposite to each other, the first surface being provided with a first adhesive layer; the multilayer structure includes a first sub-part and a second sub-part, the first sub-part being connected to the surface of the cover plate body through the first adhesive layer, the second sub-part being located on the side of the first sub-part away from the cover plate body, the first surface of the second sub-part being opposite to the first surface of the first sub-part, and at least a portion of the second sub-part and at least a portion of the first sub-part being fused together, so that the multilayer structure forms a fused structure.

[0007] Optionally, the fusion structure is formed by N layers of the folded edge portion, the thickness of a single layer of the folded edge portion is H0, and the height difference between the top surface of the fusion structure and the surface of the cover plate body along the height direction of the battery cell is H1, where 0 < H1 < N × H0.

[0008] Optionally, the insulating film includes a first base layer, an inner adhesive layer, and a second base layer stacked sequentially. The surface of the first base layer away from the inner adhesive layer forms a first surface of the insulating film, and the surface of the second base layer away from the inner adhesive layer forms a second surface of the insulating film. The second base layer of the first sub-part is fused with the second base layer of the second sub-part to form a fused structure of the multilayer structure.

[0009] Optionally, the multilayer structure further includes a third sub-part located on the side of the second sub-part away from the cover plate body, with the first surface of the third sub-part facing the first surface of the second sub-part; the second base layer of the first sub-part is fused with the second base layer of the second sub-part, and the first adhesive layer disposed in the third sub-part is fused with the first adhesive layer disposed in the second sub-part, so that the multilayer structure forms a fused structure.

[0010] Optionally, the second sub-part and the first sub-part are thermo-pressed together to form the fused structure from the multilayer structure.

[0011] Optionally, an adhesive layer connects the folded edges of each two adjacent layers in the multilayer structure.

[0012] Optionally, the insulating film has a first surface and a second surface disposed opposite to each other; the adhesive layer includes a first adhesive layer disposed on the first surface and a second adhesive layer disposed on the second surface; the multilayer structure includes a first sub-part and a second sub-part, the first sub-part being connected to the surface of the cover plate body through the first adhesive layer, the second sub-part being located on the side of the first sub-part away from the cover plate body, and the second surface of the second sub-part being opposite to the second surface of the first sub-part; the second adhesive layer is connected to at least a portion of the area between the second sub-part and the first sub-part.

[0013] Optionally, the second adhesive layer is disposed only in the multilayer structure.

[0014] Optionally, the second adhesive layer is also disposed in at least a portion of the folded edge, excluding the multilayer structure.

[0015] Optionally, the second adhesive layer is disposed on the entire second surface.

[0016] Optionally, the folded edge extends along the edge of the cover plate body, and the dimension of the folded edge perpendicular to the extension direction is the width of the folded edge, and the dimension of the second adhesive layer along the width direction of the folded edge is not less than the width of the folded edge.

[0017] Optionally, the second adhesive layer includes a hot melt adhesive layer.

[0018] Optionally, the material of the second adhesive layer is at least one selected from ethylene vinyl acetate copolymer, anhydride-modified ethylene vinyl acetate copolymer, ethylene methacrylate copolymer, ethylene acrylic acid copolymer, polyethersulfone resin, polyethylene, polypropylene, ethylene methyl acrylate copolymer, polyamide, polylactic acid, and polyester.

[0019] Optionally, the second adhesive layer includes a cast adhesive layer.

[0020] Optionally, the second adhesive layer includes an adhesive layer formed by coating.

[0021] Optionally, the second adhesive layer includes a cast adhesive layer, and the thickness of the cast adhesive layer is 5 micrometers to 30 micrometers.

[0022] Optionally, the second adhesive layer includes a coated adhesive layer, and the thickness of the coated adhesive layer is from 0.5 micrometers to 20 micrometers.

[0023] Optionally, the thickness of the insulating film is 50 micrometers to 150 micrometers.

[0024] Optionally, a panel assembly is mounted on the surface of the cover body, the panel assembly including at least one of an electrode post and an explosion-proof valve; the width of the folded edge is W1; the dimension of the cover body along the thickness direction of the battery cell is W2; the maximum dimension of the panel assembly along the thickness direction of the battery cell is W3; the ratio of W1 to (W2-W3) / 2 is x, 0.2≤x≤1.

[0025] Optionally, the folded edge portion is spaced apart from the panel assembly, and the minimum distance between the folded edge portion and the panel assembly is L1, where 0.5mm≤L1≤4mm.

[0026] Optionally, the housing has two opening ends, which are located on opposite sides of the housing; the dimension of the insulating film along the height direction of the battery cell is L, and the height of the housing is L2, where L < L2 + (W2 - W3).

[0027] Optionally, the folded portion includes a wide sub-portion extending along the thickness direction of the battery cell and a long sub-portion extending along a second direction; the second direction, the thickness direction of the battery cell, and the height direction of the battery cell are perpendicular to each other; at least one end of the wide sub-portion is formed with a wide fold line, and a wide redundant sub-portion capable of flipping around the wide fold line, the wide fold line intersecting with the edge of the cover plate body; at least one end of the long sub-portion is formed with a long fold line, and a long redundant sub-portion capable of flipping around the long fold line, the long fold line intersecting with the edge of the cover plate body; the wide redundant sub-portion is connected to the long redundant sub-portion and folded towards the long sub-portion or the wide sub-portion to form the multilayer structure.

[0028] Optionally, along the height direction of the battery cell, the orthographic projection of the multilayer structure onto the surface of the cover plate body is triangular.

[0029] Optionally, the battery cell further includes a top patch, which is located on the side of the folded edge away from the cover plate body and is connected to the cover plate body and / or to the folded edge; along the height direction of the battery cell, the projection of the top patch and the folded edge on the cover plate body at least partially overlaps.

[0030] Based on the same inventive concept, the second aspect of this application also provides a battery, including a battery cell as described in the first aspect.

[0031] As can be seen from the above, the battery cell and battery provided in this application have interconnected edges between adjacent layers in the multilayer structure. This not only prevents problems such as warping, folding, or damage to the insulating film, but also ensures that the structural components connected to the insulating film can form a reliable connection with the insulating film, thereby improving the appearance of the battery cell, ensuring that the battery cell has good insulation performance, and thus improving the safety and service life of the battery cell. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of a battery cell with a first structure according to an embodiment of this application;

[0034] Figure 2 This is a schematic diagram of a battery cell with a second structure according to an embodiment of this application;

[0035] Figure 3 This is a partial schematic diagram of the insulating film of a battery cell extending beyond the opening end, which is not connected to the cover plate body according to an embodiment of this application.

[0036] Figure 4 This is a partial schematic diagram of the process of connecting the battery cell to the insulating film on the cover plate body according to an embodiment of this application;

[0037] Figure 5 This is a partial schematic diagram showing the completion of connecting the insulating film from the battery cell to the cover plate body according to an embodiment of this application.

[0038] Figure 6 for Figure 5 Schematic diagram of the cross-section BB in the middle;

[0039] Figure 7 The battery cell of the third structure in the embodiments of this application is in Figure 5 Schematic diagram of the cross-section BB in the middle;

[0040] Figure 8 This is a schematic diagram of the microstructure of a single-layer insulating film according to an embodiment of this application;

[0041] Figure 9 This is a microscopic structural diagram of the multilayer structure of a battery cell according to an embodiment of this application.

[0042] Figure 10 This is a schematic diagram of the microstructure of the fused structure of a single battery cell according to an embodiment of this application.

[0043] Figure 11 This is a schematic diagram showing the height change of the folded edge of a battery cell after it has been heat-pressed.

[0044] Figure 12 This is a schematic diagram showing the height variation of the folded edge of a battery cell before it was heat-pressed.

[0045] Figure 13 This is a schematic diagram showing the height comparison of a single battery cell with two open ends before and after forming a fused structure, according to an embodiment of this application.

[0046] Figure 14 The battery cell of the fourth structure in the embodiments of this application is in Figure 5 Schematic diagram of the cross-section BB in the middle;

[0047] Figure 15 The battery cell of the fifth structure in the embodiments of this application is in Figure 5 Schematic diagram of the cross-section BB in the middle;

[0048] Figure 16 This is a partial schematic diagram of a battery cell with an open end in an embodiment of this application, showing the formation of a second adhesive layer on the insulating film.

[0049] Figure 17 This is a partial schematic diagram of a battery cell with two open ends in an embodiment of this application, showing the formation of a second adhesive layer on the insulating film.

[0050] Figure 18 This is a schematic diagram of a battery cell with a sixth structure according to an embodiment of this application;

[0051] Figure 19 This is a schematic diagram of a battery cell with a seventh structure according to an embodiment of this application;

[0052] Figure 20 This is a top view schematic diagram of a battery cell with an open end according to an embodiment of this application;

[0053] Figure 21 This is a top view schematic diagram of a battery cell with two open ends according to an embodiment of this application.

[0054] Explanation of reference numerals in the attached figures:

[0055] 100. Shell; 110. Open end;

[0056] 200. Insulating film; 210. Folded edge; 211. Multilayer structure; 2111. First sub-section; 2112. Second sub-section; 2113. Third sub-section; 212. Single-layer structure; 213. Double-layer structure; 214. Fusion structure; 215. Longitudinal sub-section; 2151. Longitudinal crease line; 2152. Longitudinal redundant sub-section; 216. Width sub-section; 2161. Width crease line; 2162. Width redundant sub-section; 220. First surface; 230. Second surface; 240. Adhesive layer; 241. First adhesive layer; 242. Second adhesive layer; 250. First base layer; 260. Inner adhesive layer; 270. Second base layer;

[0057] 300. Cover plate assembly; 310. Cover plate body; 311. Length edge; 312. Width edge; 320. Panel assembly; 321. Pole post; 322. Explosion-proof valve;

[0058] 400, Top patch; 410, Cutout area. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0060] It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components described in these embodiments do not limit the scope of this application.

[0061] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0062] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0063] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by those skilled in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components.

[0064] Words such as "include" or "contain" mean that the element or object preceding the word covers the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "up," "down," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0065] To achieve insulation of the battery cell, an insulating film is wrapped around its outer surface. This insulating film has two opposing surfaces: one with an adhesive layer (hereinafter referred to as the adhesive side) and the other without (hereinafter referred to as the non-adhesive side). The insulating film is connected to the housing through the adhesive side. The folded edges formed on the cover plate assembly surface of the insulating film are prone to damage or warping, thus affecting insulation performance. The inventors, in their research on this problem, discovered that the folded edges form a multi-layered structure at the corners of the cover plate assembly. In this multi-layered structure, the non-adhesive sides of adjacent layers may face each other, preventing a reliable connection between the two layers. This leads to problems such as warping and damage at the folded edges, negatively impacting the insulation performance of the battery cell. Further research in this invention has resulted in a battery cell that solves the problem of easy damage or warping at the folded edges, improving insulation performance.

[0066] Figure 1 A schematic diagram of a battery cell with the first structure is shown. Figure 1 Taking the structure and orientation shown as an example, the battery cell may include a housing 100 and a cover assembly 300. The housing 100 has an opening 110 only at the top, that is, the housing 100 has one opening 110. The cover assembly 300 includes a cover body 310, and terminals 321 (including a positive terminal and a negative terminal) and an explosion-proof valve 322 connected to the cover body 310. The cover body 310 covers the opening 110.

[0067] For example, the cover body 310 and the housing 100 can be connected by welding.

[0068] Figure 2 A schematic diagram of a battery cell with the second structure is shown. Figure 2 Taking the structure and orientation shown as an example, the housing 100 may also have two open ends 110, with the two open ends 110 along the height direction of the housing 100 (e.g., Figure 2 The cover plate assemblies are arranged relative to each other in the Z direction. Accordingly, there are two cover plate assemblies 300, each of which is connected to the opening end 110 in a one-to-one correspondence. Each cover plate assembly 300 includes a cover plate body 310, and each cover plate body 310 is connected to a pole post 321 (one cover plate body 310 is connected to a positive pole post, and the other cover plate body 310 is connected to a negative pole post) and an explosion-proof valve 322.

[0069] Whether it is the battery cell with the first structure or the battery cell with the second structure, the outer surface of the casing 100 is covered with an insulating film 200.

[0070] by Figure 1 Taking the structure shown as an example, when the insulating film 200 is applied to the surface of the housing 100, a portion of the insulating film 200 will extend along the height direction of the battery cell (e.g., Figure 1 The part (in the Z direction, hereinafter referred to as the first direction) extends beyond the cover plate body 310. After bending, this part can be connected to the cover plate body 310 and is constructed as a folded edge 210.

[0071] Specifically, Figure 3 A partial schematic diagram is shown when the insulating film 200 extending beyond the cover plate body 310 is not connected to the cover plate body 310. (See attached diagram.) Figure 3 At this time, the portion of the insulating film 200 extending beyond the cover plate body 310 is in a vertical state along the first direction, and this portion includes the length edge near the cover plate body 310 (i.e., along the length edge). Figure 3 The portion on one side of the edge extending in the X direction (hereinafter referred to as the longitudinal portion), and the width edge near the cover body 310 (i.e., along the... Figure 3 The portion on one side of the edge extending in the Y direction (hereinafter referred to as the width portion) is continuous or at least partially interrupted between the length portion and the width portion.

[0072] Due to differences in actual production processes or battery cell sizes, the method of applying the insulating film 200 to the battery cell may vary. Therefore, in some embodiments, the longitudinal portion and the transverse portion of the insulating film 200 are continuous or at least partially interrupted, while in other embodiments, the longitudinal portion and the transverse portion may be continuous or at least partially interrupted.

[0073] When the insulating film 200 has an adhesive layer on only one surface along its thickness direction, the portion of the insulating film 200 extending beyond the cover plate body 310 has an adhesive surface. Figure 3 The center point pattern area faces the cover plate body 310, and the non-adhesive surface is away from the cover plate body 310.

[0074] Figure 4 A partial schematic diagram shows the process of attaching the insulating film 200 to the cover plate body 310. (See attached diagram.) Figure 4 First, the longitudinal portion can be folded along the length edge of the cover plate body 310 and applied to the surface of the cover plate body 310 to form the longitudinal sub-part 215 of the folded edge portion 210. At this time, the adhesive side of the longitudinal sub-part 215 is in contact with the surface of the cover plate body 310, and the non-adhesive side is not in contact with the surface of the cover plate body 310. Figure 4 The central cross pattern portion faces upwards. It should be noted that at this time, the end of the longitudinal sub-part 215 will have a longitudinal redundant sub-part 2152 extending beyond the width edge of the cover plate body 310. The longitudinal redundant sub-part 2152 can be flipped along the longitudinal fold line 2151 intersecting the edge of the cover plate body 310. The adhesive surface of the longitudinal redundant sub-part 2152 will connect with the adhesive surface of the width portion, forming an overlapping area between the longitudinal and width portions (hereinafter referred to as the overlapping area).

[0075] Figure 5 A partial schematic diagram shows the completed process of attaching the insulating film 200 to the cover plate body 310. (See attached diagram.) Figure 4 and Figure 5 After forming the elongated sub-section 215, the wide portion can be folded along the width edge of the cover body 310 and attached to the surface of the cover body 310 to form the wide sub-section 216 of the folded edge portion 210. At this time, the end of the wide sub-section 216 forms a wide crease line 2161 near the overlapping area, and the portion of the folded edge portion 210 located in the overlapping area forms a wide redundant sub-section 2162. The overlapping area can be flipped along the elongated crease line 2151 toward the adhesive-free surface of the elongated sub-section 215, and a multi-layered structure 211 is formed there, while the elongated sub-section 215 and the wide sub-section 216 form a single-layered structure 212 provided along the edge of the cover body 310.

[0076] The above process is one way to cover the outer surface of the battery cell with an insulating film 200, wherein the folding order of the insulating film 200 is not particularly limited. That is, the wide portion of the insulating film 200 can be folded and applied to the surface of the cover body 310 first to form the wide sub-portion 216 of the folded edge portion 210, and then the long portion can be folded along the long edge of the cover body 310 and applied to the surface of the cover body 310 to form the long sub-portion 215. At this time, the overlapping area will be flipped along the wide fold line 2161 to the adhesive-free surface of the wide sub-portion 216, and a similar multi-layer structure 211 and single-layer structure 212 will be formed there.

[0077] Furthermore, the portion of the insulating film 200 where the longitudinal and lateral portions connect—that is, the portion of the insulating film 200 near a corner of the cover plate body 310—can be bonded together to form a two-layer structure. Then, the longitudinal portion of the insulating film 200 is applied to the surface of the cover plate body 310 to form a longitudinal sub-part 215, and the lateral portion is also applied to the surface of the cover plate body 310 to form a lateral sub-part 216. These two layers form interconnected longitudinal redundant sub-parts 2152 and lateral redundant sub-parts 2162. A longitudinal fold line 2151 is formed at the root of the longitudinal redundant sub-part 2152 near the cover plate body 310, and a lateral fold line 2161 is formed at the root of the lateral redundant sub-part 2162. These two layers can be flipped along the longitudinal fold line 2151 towards the longitudinal sub-part 215, or along the lateral fold line 2161 towards the lateral sub-part 216, to form the aforementioned multi-layer structure 211.

[0078] Figure 6 Showing Figure 5 A schematic diagram of the cross-section BB in the middle section. Figure 4 , Figure 5 and Figure 6 The multi-layer structure 211 includes a first sub-part 2111 constructed from a longitudinal sub-part 215, a second sub-part 2112 constructed from a longitudinal redundant sub-part 2152, and a third sub-part 2113 constructed from a wide redundant sub-part 2162. The first sub-part 2111, the second sub-part 2112 and the third sub-part 2113 are stacked sequentially along the surface direction away from the cover plate body 310.

[0079] It needs to be clarified that yes, Figure 6 The diagonal line layer in the figure represents the adhesive layer disposed on the adhesive surface of the insulating film 200. Figure 6 The structure shown is only for clearly demonstrating the specific structure of the multi-layer structure 211, the long sub-section 215, and the wide sub-section 216, and is not intended to define the relative positions between the multi-layer structure 211, the long sub-section 215, and the wide sub-section 216.

[0080] like Figure 6 Since the first sub-part 2111 and the second sub-part 2112 are facing each other without adhesive, an effective connection cannot be formed between them. Over time, the insulating film 200 at the multilayer structure 211 will spring back, causing the first sub-part 2111 and the second sub-part 2112 to separate from each other, resulting in a warping problem at the multilayer structure 211.

[0081] like Figure 1The width of the folded edge 210 is W1. The aforementioned warping problem is particularly noticeable when the width W1 of the folded edge 210 is small (for example, the width of the folded edge 210 is 1 mm to 5 mm). Warping of the insulating film 200 not only affects the appearance of the battery cell, but also has an adverse effect on the insulation performance of the battery cell.

[0082] To avoid the above problems, this application provides a single battery cell.

[0083] Figure 7 The third type of battery cell structure was demonstrated. Figure 5 A schematic diagram of the cross-section of section BB, as shown below. Figure 1 and Figure 7 The battery cell includes: a housing 100 having at least one open end 110; a cover body 310 covering the open end 110; an insulating film 200 covering the housing 100; the portion of the insulating film 200 extending beyond the cover body 310 along a first direction is bent and fixed to the cover body 310, forming a folded edge 210; the folded edges 210 are stacked along the first direction in a portion of the cover body 310 to form a multilayer structure 211, and each adjacent two layers of folded edges 210 in the multilayer structure 211 are interconnected.

[0084] For example, in the multilayer structure 211, the connection between two adjacent folded edges 210 can be adhesive bonding or hot pressing bonding.

[0085] For example, the top surface of the cover body 310 can be a rounded rectangle, and the multi-layer structure 211 can be set at the long side, short side or rounded corner of the rounded rectangle.

[0086] For example, the folded edge 210 can be glued to the surface of the cover plate body 310.

[0087] In this embodiment, the adjacent two layers of folded edges 210 in the multilayer structure 211 are connected to each other, and the adjacent two layers of folded edges 210 in the multilayer structure 211 can provide mutual tension, thereby preventing the adjacent two layers of folded edges 210 in the multilayer structure 211 from separating from each other, and thus avoiding the insulation film 200 from warping.

[0088] The battery cell provided in this application embodiment has two adjacent folded edges 210 in the multilayer structure 211 that are interconnected. This not only prevents the insulating film 200 from warping, folding or being damaged, but also ensures that the structural components connected to the insulating film 200 can form a reliable connection with the insulating film 200. This improves the appearance of the battery cell, ensures that the battery cell has good insulation performance, and thus improves the safety and service life of the battery cell.

[0089] like Figure 1 , Figure 6 and Figure 7 In some embodiments, the insulating film 200 has a first surface 220 and a second surface 230 disposed opposite to each other, the first surface 220 being provided with a first adhesive layer 241; the multilayer structure 211 includes a first sub-part 2111 and a second sub-part 2112, the first sub-part 2111 being connected to the surface of the cover plate body 310 through the first adhesive layer 241, the second sub-part 2112 being located on the side of the first sub-part 2111 away from the cover plate body 310, the first surface 220 of the second sub-part 2112 being opposite to the first surface 220 of the first sub-part 2111, and at least a portion of the second sub-part 2112 and at least a portion of the first sub-part 2111 being fused together, so that the multilayer structure 211 forms a fused structure 214.

[0090] For example, the first adhesive layer 241 may be disposed on the entire first surface 220, or it may be disposed on a portion of the first surface 220 at a preset position.

[0091] For example, the first adhesive layer 241 may be a hot melt adhesive layer or a pressure-sensitive adhesive layer.

[0092] For example, the fusion between the second sub-part 2112 and the first sub-part 2111 can be achieved by means of thermo-press fusion, electro-fusion or chemical fusion.

[0093] by Figure 6 and Figure 7 The structure and orientation shown are used as examples for further explanation. Figure 6 Both the elongated sub-part 215 and the first sub-part 2111 can be connected to the surface of the cover plate body 310 through the first adhesive layer 241. In order for the first sub-part 2111 to be connected to the second sub-part 2112 above it, at least a portion of the second sub-part 2112 and at least a portion of the first sub-part 2111 can be fused together, for example, the portion of the second sub-part 2112 near its second surface 230 can be fused together with the portion of the first sub-part 2111 near its second surface 230.

[0094] like Figure 6 Before fusion, the second surface 230 of the first sub-part 2111 and the second surface 230 of the second sub-part 2112 can be directly attached. For example... Figure 7 After the first sub-part 2111 and the second sub-part 2112 are fused into a single structure, the multi-layer structure 211 forms a fused structure 214. At this time, the first surface 220 of the original first sub-part 2111 is connected to the surface of the cover plate body 310 through the first adhesive layer 241, and the first surface 220 of the original second sub-part 2112 is connected to the upper third sub-part 2113 through the first adhesive layer 241. The multi-layer structure 211 can then form a stable structure, and it is not easy for the problem of warping to occur.

[0095] For the fused structure 214 formed by the multi-layer structure 211 Figure 13 A schematic diagram showing the height comparison of a battery cell with two open ends before and after forming the fused structure 214 is presented.

[0096] like Figure 13 Before the fusion structure 214 is formed, the height of the battery cell is 294.91 mm (the rectangle at the top in the figure). After the fusion structure 214 is formed, the height of the battery cell is 294.67 mm (the rectangle at the bottom in the figure). Therefore, it can be determined that the height of the battery cell is reduced by 0.24 mm after the fusion structure 214 is formed. Consequently, the maximum thickness of the folded edge portion 210 on the surface of a single cover plate body 310 (i.e., the thickness of the multilayer structure 211) is reduced by 0.12 mm after the fusion structure 214 is formed. The single-layer thickness of the insulating film 200 before the fusion structure 214 is formed is 0.11 mm. Correspondingly, as... Figure 6 The total thickness of the multi-layer structure 211 formed by the three-layer folded edge portion 210 before the formation of the fusion structure 214 is 0.33 mm, while the total thickness after the formation of the fusion structure 214 is 0.33-0.12=0.21 mm. The reason for the reduction in thickness is at least the fusion of the folded edge portion 210 in the multi-layer structure 211.

[0097] As can be seen from the foregoing, the thickness variation of the multilayer structure 211 can also be used to determine whether the multilayer structure 211 forms a fused structure 214.

[0098] like Figure 6 and Figure 7 In some embodiments, the fusion structure 214 is formed by N layers of folded edges 210, the thickness of a single layer of folded edges 210 is H0, and the height difference between the top surface of the fusion structure 214 and the surface of the cover plate body 310 along the first direction is H1, where 0 < H1 < N × H0.

[0099] For example, the top surface of the fusion structure 214, that is, the surface of the fusion structure 214 that is furthest from the surface of the cover body 310.

[0100] In the fusion structure 214, if H1 is too large after at least two adjacent folded edges 210 are fused, it means that the two adjacent folded edges 210 have not been fused. Accordingly, the two adjacent folded edges 210 have not been reliably connected and may still separate to a certain extent, causing the multilayer structure 211 to warp.

[0101] To address the aforementioned issues, this embodiment designs H1 as 0 < H1 < N × H0, ensuring that at least two adjacent folded edges 210 in the fusion structure 214 have been fused together to form a reliable connection, which helps prevent the fusion structure 214 from warping.

[0102] Figure 8 A schematic diagram of the microstructure of a single-layer insulating film is shown. Figure 9 A schematic diagram of the microstructure of a single battery cell is shown. Figure 10 A schematic diagram of the microstructure of the fused battery cell is shown.

[0103] like Figure 8 , Figure 9 and Figure 10 In some embodiments, the insulating film 200 includes a first base layer 250, an inner adhesive layer 260 and a second base layer 270 stacked sequentially. The surface of the first base layer 250 away from the inner adhesive layer 260 forms a first surface 220 of the insulating film 200, and the surface of the second base layer 270 away from the inner adhesive layer 260 forms a second surface 230 of the insulating film 200. The second base layer 270 of the first sub-part 2111 is fused with the second base layer 270 of the second sub-part 2112 so that the multilayer structure 211 forms a fused structure 214.

[0104] It should be noted that, in this application, in order to more clearly illustrate the structure of the insulating film 200, the first base layer 250, the inner adhesive layer 260, the second base layer 270, and the aforementioned first adhesive layer 241 of the insulating film 200 are described separately. However, in conjunction with... Figure 8 It is understandable that the single-layer insulating film 200 actually includes a first base layer 250, an inner adhesive layer 260, a second base layer 270, and a first adhesive layer 241 disposed on the first surface 220.

[0105] For example, the materials of the first base layer 250 and the second base layer 270 may be the same or different.

[0106] For example, the inner adhesive layer 260 and the first adhesive layer 241 may be made of the same or different materials.

[0107] like Figure 9 In the multi-layer structure 211, the second base layer 270 of the first sub-part 2111 and the second base layer 270 of the second sub-part 2112 are attached together. As can be seen from the foregoing, when the two are not connected, the multi-layer structure 211 may experience warping.

[0108] To address the aforementioned issues, this embodiment fuses the two components to form an integrated structure. On one hand, this integrated structure is more stable and less prone to splitting; correspondingly, the fused structure 214 is less likely to warp. On the other hand, the thickness of the integrated structure formed by fusion is less than the total thickness of the two stacked folded edges 210. That is, the thickness of the fused structure 214 after fusion is less than the thickness of the multilayer structure 211 before fusion. Consequently, the overall height of the battery cell can be reduced, which helps to improve the energy density of the battery cell.

[0109] like Figure 8 , Figure 9 and Figure 10 In some embodiments, the multilayer structure 211 further includes a third sub-part 2113, which is located on the side of the second sub-part 2112 away from the cover plate body 310. The first surface 220 of the third sub-part 2113 faces the first surface 220 of the second sub-part 2112. The second base layer 270 of the first sub-part 2111 is fused with the second base layer 270 of the second sub-part 2112. The first adhesive layer 241 disposed in the third sub-part 2113 is fused with the first adhesive layer 241 disposed in the second sub-part 2112, so that the multilayer structure 211 forms a fused structure 214.

[0110] When the multilayer structure 211 includes three folded edges 210, the second base layer 270 of the first sub-part 2111 and the second base layer 270 of the second sub-part 2112 are bonded together, and the first adhesive layer 241 disposed in the second sub-part 2112 and the first adhesive layer 241 disposed in the third sub-part 2113 are interconnected. As can be seen from the foregoing, the second base layer 270 of the first sub-part 2111 and the second base layer 270 of the second sub-part 2112 are fused together. Furthermore, since the first adhesive layer 241 disposed in the third sub-part 2113 and the first adhesive layer 241 disposed in the second sub-part 2112 are made of the same material, fusion can also be achieved. This not only potentially improves the connection strength between the third sub-part 2113 and the second sub-part 2112, but also helps to reduce the thickness of the fused structure 214. Correspondingly, the overall height of the battery cell can be reduced, which helps to improve the energy density of the battery cell.

[0111] like Figure 1 and Figure 7 In some embodiments, the second sub-part 2112 and the first sub-part 2111 are thermally pressed together to form a fused structure 214 from the multilayer structure 211.

[0112] For example, when hot-pressing the multilayer structure 211, the hot-pressing temperature can be between 220°C and 260°C, preferably between 230°C and 240°C. If the hot-pressing temperature is too low, the second sub-part 2112 and the first sub-part 2111 cannot achieve a reliable fusion bond, and there is still a risk of separation. If the hot-pressing temperature is too high, the second sub-part 2112 or the first sub-part 2111 may melt through, leading to insulation failure. Therefore, the hot-pressing temperature can be designed to be between 220°C and 260°C, which can ensure that the second sub-part 2112 and the first sub-part 2111 can reliably fusion bond while preventing melt-through and ensuring the insulation performance of the battery cell.

[0113] For example, when hot-pressing the multi-layer structure 211, the hot-pressing pressure can be from 50N to 500N, preferably 200N. If the hot-pressing pressure is too low, the second sub-part 2112 and the first sub-part 2111 cannot achieve a reliable fusion bond, and there is still a risk of separation. If the hot-pressing pressure is too high, it will affect the flatness of the hot-pressing surface of the hot-pressing equipment during long-term mass production. Therefore, the hot-pressing pressure can be designed to be from 50N to 500N, which can ensure a reliable fusion bond between the second sub-part 2112 and the first sub-part 2111, and also extend the service life of the hot-pressing equipment.

[0114] It should be noted that the heat-pressing pressure and heat-pressing temperature can be designed based on the above range, according to the material thickness and material of the insulating film 200 and the number of layers of the folded edge portion 210 in the multi-layer structure 211.

[0115] During the hot pressing process, at least a portion of the first sub-part 2111 and the second sub-part 2112 will be in a molten state at high temperature. After being subjected to external pressure (which can act on the multilayer structure 211 from top to bottom along the first direction), the first sub-part 2111 and the second sub-part 2112 in the molten state can be melted and bonded to form an integrated structure, that is, fusion is achieved.

[0116] Of course, by hot pressing, not only can the second base layer 270 of the first sub-part 2111 and the second base layer 270 of the second sub-part 2112 be fused together, but the first adhesive layer 241 provided in the third sub-part 2113 and the first adhesive layer 241 provided in the second sub-part 2112 can also be fused together.

[0117] When at least two adjacent folded edges 210 in the multilayer structure 211 are heat-pressed together, the effect that can be achieved can be demonstrated by the following data.

[0118] Example 1

[0119] This embodiment provides a battery cell in which the folded edge portion 210 (including at least a multi-layer structure 211) on the surface of the cover body 310 is hot-pressed, and a structural layer (e.g., a top patch 400) is attached to the cover assembly 300.

[0120] Comparative Example 1

[0121] Comparative Example 1 provides a battery cell that differs from Example 1 only in that the folded edge 210 on the surface of the cover body 310 is not hot-pressed.

[0122] Twenty cells of each of the battery cells provided in Example 1 and Comparative Example 1 were tested. Figure 11 The diagram illustrates the height change data of Example 1 stored for multiple cycles (each cycle being 24 hours) in an environment of 85°C / 85%Rh. Figure 12 The diagram illustrates the height change data of Comparative Example 1 stored for multiple cycles (each cycle being 24 hours) in an environment of 85℃ / 85%Rh.

[0123] Combination Figure 11 and Figure 12 It can be seen that after one continuous storage period, the height of Example 1 increased by 0.05 mm, and the height of Comparative Example 1 increased by 0.16 mm. The height of Comparative Example 1 continued to increase over time. After three continuous storage periods, none of the 20 battery cells in Example 1 showed any warping issues. However, in Comparative Example 1, four of the 20 battery cells exhibited warping issues in their respective multilayer structures 211.

[0124] Figure 14 The fourth type of battery cell structure was demonstrated. Figure 5 A schematic diagram of the cross-section BB in the middle section. Figure 1 and Figure 14 In some embodiments, an adhesive layer 240 is connected between each pair of adjacent folded edges 210 in the multilayer structure 211.

[0125] For example, in the multilayer structure 211, the adhesive layer 240 may be disposed in a portion of the area between two adjacent folded edges 210, or in the entire area between two adjacent folded edges 210.

[0126] For example, the adhesive layer 240 can be a hot melt adhesive layer or a pressure-sensitive adhesive layer.

[0127] In this embodiment, an adhesive layer 240 is connected between each pair of adjacent folded edges 210 in the multilayer structure 211. The adhesive layer 240 can provide adhesive force to the two folded edges 210 connected to it, so that each folded edge 210 in the multilayer structure 211 can be reliably connected, thereby preventing any two folded edges 210 in the multilayer structure 211 from separating from each other, and thus avoiding the insulation film 200 from peeling up.

[0128] like Figure 1 and Figure 14 In some embodiments, the insulating film 200 has a first surface 220 and a second surface 230 disposed opposite to each other, the adhesive layer 240 includes a first adhesive layer 241 disposed on the first surface 220 and a second adhesive layer 242 disposed on the second surface 230; the multilayer structure 211 includes a first sub-part 2111 and a second sub-part 2112, the first sub-part 2111 is connected to the surface of the cover plate body 310 through the first adhesive layer 241, the second sub-part 2112 is located on the side of the first sub-part 2111 away from the cover plate body 310, and the second surface 230 of the second sub-part 2112 is opposite to the second surface 230 of the first sub-part 2111; the second adhesive layer 242 is connected to at least a portion of the area between the second sub-part 2112 and the first sub-part 2111.

[0129] It should be noted that the second adhesive layer 242 disposed on the second surface 230 can also be part of the single-layer insulating film 200. That is, the single-layer insulating film 200 may include a first base layer 250, an inner adhesive layer 260, a second base layer 270, a first adhesive layer 241 disposed on the first surface 220, and a second adhesive layer 242 disposed on the second surface 230.

[0130] For example, the second adhesive layer 242 can be a hot melt adhesive layer or a pressure-sensitive adhesive layer, and the type, formation method and material of the first adhesive layer 241 can be the same as or different from the type, formation method and material of the second adhesive layer 242.

[0131] by Figure 14 Taking the structure and orientation shown as an example, the folded edge portion 210 will be further explained. The single-layer structure 212 formed by the folded edge portion 210, as well as the first sub-part 2111 in the multi-layer structure 211, can be connected to the surface of the cover plate body 310 through the first adhesive layer 241. The second sub-part 2112 located above the first sub-part 2111 needs to be glued to the first sub-part 2111 through the second adhesive layer 242.

[0132] Regarding the location and area of ​​the second adhesive layer 242 in the multilayer structure 211, it only needs to provide sufficient adhesive force (to prevent lifting) to the multilayer structure 211. For example... Figure 4The second adhesive layer 242 can be disposed in a portion of the overlapping area, or in all of the overlapping area, or in other parts of the folded edge 210 except for the multi-layer structure 211 (e.g., the single-layer structure 212).

[0133] In some embodiments, the second adhesive layer 242 is disposed only in the multilayer structure 211.

[0134] by Figure 4 Taking the structure shown as an example, the second adhesive layer 242 can be disposed in the overlapping area. By disposing of the second adhesive layer 242 only in the multilayer structure 211 of the folded edge portion 210, and omitting it from other parts of the folded edge portion 210, the amount of the second adhesive layer 242 used can be reduced, thus lowering material costs. Simultaneously, when the second adhesive layer 242 is a general adhesive layer (i.e., an adhesive layer that has high adhesion under normal conditions without requiring heating, pressure, or light exposure), since general adhesive layers maintain high adhesion even when not connected to structural components, disposing of the second adhesive layer 242 over a large area may cause inconvenience in the battery cell assembly process. Therefore, if the second adhesive layer 242 is disposed only in the multilayer structure 211, after the multilayer structure 211 is formed, the other exposed surfaces of the folded edge portion 210 will not have adhesiveness, facilitating subsequent battery cell assembly processes.

[0135] In some embodiments, a second adhesive layer 242 may be formed using materials such as pressure-sensitive adhesive or hot melt adhesive, so that the second adhesive layer 242 has low or no adhesion under normal conditions, thus preventing inconvenience to the production and assembly process of battery cells or batteries when the second adhesive layer 242 is provided in areas other than the multilayer structure 211.

[0136] Figure 15 The fifth type of battery cell structure was demonstrated. Figure 5 Schematic diagram of the cross section BB in the middle.

[0137] like Figure 15 In some embodiments, the second adhesive layer 242 is also disposed in at least a portion of the folded edge 210, excluding the multilayer structure 211.

[0138] For example, the portion of the folded edge 210 other than the multi-layer structure 211 may include a single-layer structure 212 formed by one layer of folded edge 210, and a double-layer structure 213 formed by two stacked folded edge portions 210 (e.g., Figure 2 In the double-layer structure 213, the lower layer folded edge 210 is connected to the surface of the cover plate body 310 through the first adhesive layer 241, and the upper layer folded edge 210 is connected to the lower layer folded edge 210 through at least the first adhesive layer 241.

[0139] Combination Figure 1It can be seen that the area of ​​the multilayer structure 211 projected onto the cover plate body 310 along the first direction is small, making it difficult to accurately locate the multilayer structure 211 when the insulating film 200 is in a flattened state. Furthermore, it is also inconvenient to form the second adhesive layer 242 in the multilayer structure 211 after the folded edge 210 has been formed.

[0140] Compared to the positioning multilayer structure 211, the positioning folded edge portion 210 is easier to form, making it easier to form the second adhesive layer 242 when the insulating film 200 is in the unfolded state.

[0141] Specifically, Figure 16 This diagram illustrates the formation of a second adhesive layer 242 on the insulating film 200 for a battery cell with an open end 110. It should be noted that... Figure 16 The diagram shown is a front view of a single battery cell (i.e., the front view of the sidewall with the larger surface area) and the insulating film 200 is not folded to form a folded edge 210.

[0142] Combination Figure 1 and Figure 16 Based on the surface dimensions of the housing 100, the portion of the insulating film 200 that extends beyond the opening end 110 can be easily determined. This portion is the part used to form the folded edge 210, and a second adhesive layer 242 can be formed in a predetermined area of ​​this portion.

[0143] Similarly, Figure 17 A schematic diagram is shown showing the formation of a second adhesive layer 242 on an insulating film 200 for a battery cell with two open ends 110.

[0144] Since the insulating film 200 will extend beyond the two oppositely arranged opening ends 110, the insulating film 200 will form a folded edge 210 at each opening end 110. Correspondingly, a second adhesive layer 242 can be provided at each position where a folded edge 210 will be formed.

[0145] In some embodiments, the second adhesive layer 242 is disposed on the entire second surface 230.

[0146] In addition to connecting adjacent folded edges 210 in the multilayer structure 211, the second adhesive layer 242 can also be used to connect other structural components or other battery cells. In this case, the area of ​​the second adhesive layer 242 on the second surface 230 of the insulating film 200 can be further expanded, or the entire second surface 230 can be covered.

[0147] For example, when the second adhesive layer 242 is applied to the entire second surface 230, the battery cell can be connected to the bottom plate surface of the housing through the second adhesive layer 242, thereby improving the connection reliability between the battery cell and the housing. As another example, the second adhesive layer 242 can be used to connect the battery cell to heat exchange devices (such as liquid cooling plates or heating layers), allowing the battery cell and heat exchange devices to maintain close contact, thereby improving the heat exchange effect of the battery cell.

[0148] like Figure 1 and Figure 14 In some embodiments, the folded edge 210 extends along the edge of the cover plate body 310, and the dimension of the folded edge 210 perpendicular to the extension direction is defined as the width W1 of the folded edge 210. The dimension of the second adhesive layer 242 along the width direction of the folded edge 210 (hereinafter referred to as the width of the second adhesive layer 242) is not less than the width W1 of the folded edge 210.

[0149] For example, the second adhesive layer 242 may extend beyond the edge of the folded portion 210 and onto the surface of the cover body 310, but will not extend to structures such as the pole 321, the explosion-proof valve 322, or the injection hole.

[0150] If the width of the second adhesive layer 242 disposed on the folded edge portion 210 is too small, the connection area between it and the first sub-part 2111 and the second sub-part 2112 in the multi-layer structure 211 will also be correspondingly small, making it difficult to maintain a reliable connection between the first sub-part 2111 and the second sub-part 2112; if the width is too large, the second adhesive layer 242 will extend to the surface of the cover plate body 310, which may have an adverse effect on the explosion-proof valve 322 or the injection hole connected to the cover plate body 310, for example, it may hinder the opening of the explosion-proof valve 322 or block the injection hole.

[0151] Therefore, in order to avoid the above problems, the width of the second adhesive layer 242 in this embodiment is designed to be no less than the width W1 of the folded edge portion 210. The second adhesive layer 242 can reliably connect the first sub-part 2111 and the second sub-part 2112 in the multilayer structure 211.

[0152] It should also be noted that for insulating films 200 with a larger folded edge 210, the area of ​​the wide sub-section 216 connected to the cover body 310 via the first adhesive layer 241 is larger, resulting in a greater restraining force on the multilayer structure 211. Therefore, even if the area of ​​the second adhesive layer 242 is smaller, the problem of the insulating film 200 lifting can be avoided. However, for some battery cells, due to size limitations, the cover assembly 300 does not have enough space for the insulating film 200 to form a wider folded edge 210. Consequently, the restraining force on the multilayer structure 211 is also smaller. Therefore, a wider second adhesive layer 242 needs to be provided on the folded edge 210 to prevent the insulating film 200 from lifting.

[0153] Figure 18 A schematic diagram of the sixth type of battery cell is shown.

[0154] like Figure 18 In some embodiments, the battery cell further includes a top patch 400, which is located on the side of the folded edge 210 away from the cover body 310 and is connected to the cover body 310 and / or to the folded edge 210; along the first direction, the projection of the top patch 400 and the folded edge 210 on the cover body 310 at least partially overlaps.

[0155] For example, the top patch 400 is provided with a cutout area 410. The cutout area 410 is used to avoid structures such as the terminal post 321, explosion-proof valve 322 and liquid injection hole connected to the cover plate body 310, and can also be used to identify the positive and negative terminals of the battery cell.

[0156] For example, the top patch 400 can be connected to the surface of the cover body 310 and / or the second surface 230 of the folded edge 210 by adhesive bonding.

[0157] For example, the top patch 400 can be connected to the cover plate body 310 or the folded edge portion 210 by an adhesive layer formed on its surface; or, an adhesive layer can be formed on the surface of the cover plate body 310 to connect the top patch 400 to the cover plate body 310; or, the top patch 400 can be connected to the folded edge portion 210 by a second adhesive layer 242 formed on the folded edge portion 210.

[0158] by Figure 18 Taking the structure and orientation shown as an example, the top patch 400 is located above the folded edge 210. When the top patch 400 is connected to the cover plate body 310 or the folded edge 210, the top patch 400 can cover at least a part of the folded edge 210, thereby providing a downward pressure force on the folded edge 210 to further prevent the folded edge 210 from lifting.

[0159] It should also be noted that, as can be seen from the foregoing, the second surface 230 of the single-layer structure 212 faces the top patch 400. When the second surface 230 of the single-layer structure 212 is provided with the second adhesive layer 242, the top patch 400 can be connected to the folded edge 210 through the second adhesive layer 242. This can eliminate the need for the process of forming an adhesive layer on the top patch 400, which helps to simplify the assembly process of the battery cell and improve assembly efficiency.

[0160] Figure 18 The diagram shows a battery cell with a housing 100 having one open end 110. For a battery cell with a housing 100 having two open ends 110, a top patch 400 can also be provided.

[0161] Figure 19 A schematic diagram of the seventh type of battery cell is shown.

[0162] like Figure 19 When the housing 100 of the battery cell has two open ends 110, the battery cell is also provided with two top patches 400, which correspond one-to-one with the two open ends 110. The connection method between the top patches 400 and the cover plate assembly 300 that covers the open ends 110 is the same as described above, and will not be repeated here.

[0163] In some embodiments, the second adhesive layer 242 includes a hot melt adhesive layer.

[0164] For example, the melting point of the hot melt adhesive layer is between 50 and 200°C.

[0165] A second adhesive layer 242 can be formed on the second surface 230 of the flattened insulating film 200. After the insulating film 200 wraps the housing 100 in a preset manner, a hot-pressing process (e.g., hot-pressing temperature 80-250℃, time 1-5s) can be used to melt the hot melt adhesive layer of the second adhesive layer 242 and generate adhesion, thereby realizing the connection between the folded edges 210 of each layer in the multilayer structure 211, or realizing the connection between the insulating film 200 and the top patch 400.

[0166] It should be noted that the hot melt adhesive layer has no or low tack at room temperature. At a predetermined time, the selected area can be heated to develop tack and complete the bonding. Specifically, at room temperature, because the hot melt adhesive layer has no tack, it facilitates the folding of the insulating film 200 when wrapping the housing 100, forming the multi-layer structure 211 in the folded edge portion 210. When the second adhesive layer 242 is needed to connect the folded edges 210 in the multi-layer structure 211, a hot-pressing process can be performed only on the multi-layer structure 211. After the hot-pressing process, a reliable connection can be formed between the folded edges 210 in the multi-layer structure 211. When the second adhesive layer 242 is needed to connect the insulating film 200 to the top patch 400, a hot-pressing process can be performed only on the single-layer structure 212 (or the entire folded edge portion 210). After the hot-pressing process, a reliable connection can be formed between the top patch 400 and the insulating film 200.

[0167] In the aforementioned context, the connection between the folded edges 210 of each layer in the multilayer structure 211, and the connection between the insulating film 200 and the top patch 400, can be performed simultaneously or sequentially.

[0168] In addition to the aforementioned beneficial effects, if pressure-sensitive adhesive is used to form the second adhesive layer 242, a release film needs to be added to the insulating film 200, and a process for removing the release film and related equipment are required during battery cell assembly, leading to a complex process and lower production efficiency. Furthermore, under normal circumstances, the adhesion of pressure-sensitive adhesive is lower than that of hot melt adhesive. Although pressure-sensitive adhesive can achieve the same effect of bonding a multi-layer structure using the second adhesive layer 242, this embodiment uses hot melt adhesive to form the second adhesive layer 242, which simplifies the process and improves the bonding reliability of the second adhesive layer 242.

[0169] In some embodiments, the second adhesive layer 242 includes an adhesive layer formed by casting.

[0170] The casting process is relatively simple, the equipment is easy to operate, and it is suitable for continuous production, which helps to improve production efficiency. At the same time, the second adhesive layer 242 formed by the casting process has uniform properties, making it suitable for mass production.

[0171] In some embodiments, the thickness of the insulating film 200 is 50 micrometers to 150 micrometers.

[0172] If the thickness of the insulating film 200 is less than 50 micrometers, it is impossible to guarantee that the battery cell has good insulation performance. If the thickness of the insulating film 200 is greater than 150 micrometers, then the problem of lifting is more likely to occur at the multilayer structure 211.

[0173] To avoid the above problems, this embodiment limits the thickness of the insulating film 200 to 50 micrometers to 150 micrometers. This not only ensures that the battery cell has good insulation performance, but also helps to reduce the risk of warping at the multilayer structure 211 of the battery cell, and can also control the volume of the battery cell, saving internal space of the battery.

[0174] In some embodiments, the thickness of the adhesive layer formed by casting is 5 micrometers to 30 micrometers.

[0175] If the thickness of the adhesive layer formed by casting is less than 5 micrometers, the adhesive force provided by the second adhesive layer 242 may be weak, and a reliable connection between the folded edges 210 of each layer in the multilayer structure 211 cannot be guaranteed, and there is still a risk of peeling. If the thickness of the adhesive layer formed by casting is greater than 30 micrometers, it will not only lead to increased material costs and a longer time to form the adhesive layer, but may also lead to a decrease in the adhesive strength of the adhesive layer or problems such as adhesive overflow during the process of covering the insulating film 200.

[0176] To avoid the above problems, this embodiment limits the thickness of the adhesive layer formed by casting to 5 micrometers to 30 micrometers. This ensures a reliable connection between the folded edges 210 of each layer in the multilayer structure 211, and also helps to reduce material costs, shorten the time for forming the adhesive layer, and improve production efficiency.

[0177] When the second adhesive layer 242 includes a cast adhesive layer, the effect it can achieve can be demonstrated by the following data.

[0178] Example 2

[0179] This embodiment provides a battery cell where the width of the folded edge 210 of the insulating film 200 is 1 mm. A second adhesive layer 242 is cast into at least the multilayer structure 211 of the folded edge 210. The material of the second adhesive layer 242 can be ethylene methyl acrylate copolymer (EMA), and the thickness of the second adhesive layer 242 can be 10 μm. After attaching the top patch 400 to the cover plate assembly 300, a hot-pressing process is performed on the location of the second adhesive layer 242, with process parameters of 180°C for 4 seconds.

[0180] Example 3

[0181] Example 3 provides a battery cell that differs from Example 2 only in that the width of the folded edge 210 is 3mm.

[0182] Example 4

[0183] Example 4 provides a battery cell that differs from Example 2 only in that the width of the folded edge 210 is 5mm.

[0184] Comparative Example 2

[0185] Comparative Example 2 provides a battery cell that differs from Example 2 only in that a second adhesive layer 242 is not formed on the insulating film 200.

[0186] Comparative Example 3

[0187] Comparative Example 3 provides a battery cell that differs from Example 3 only in that a second adhesive layer 242 is not formed on the insulating film 200.

[0188] Comparative Example 4

[0189] Comparative Example 4 provides a battery cell that differs from Example 4 only in that a second adhesive layer 242 is not formed on the insulating film 200.

[0190] Ten cells of each of the battery cells provided in Examples 2, 3, 4, 2, 3, and 4 were tested, and the experimental data are shown in Table 1.

[0191] Table 1 Test Data

[0192]

[0193] As can be seen from Table 1, Examples 2, 3, and 4 show that after storage at 85°C for 24 hours, no warping problem occurred in the multilayer structure 211 of all battery cells. This indicates that when the second adhesive layer 242 includes a cast adhesive layer, warping will not occur in the multilayer structure 211 regardless of whether the width of the folded edge 210 is large or small.

[0194] Comparative Example 2 shows that after the 10 battery cells were prepared, the multilayer structure 211 of each of the 10 battery cells immediately showed the problem of warping. At this time, it was no longer necessary to carry out the experiment described in the second column of "storing at 85°C for 24 hours" to count the number of battery cells with warping of multilayer structure 211.

[0195] Comparative Example 3 shows that after the 10 battery cells were prepared, the multilayer structure 211 of 5 of the battery cells had warped. After being stored at 85°C for 24 hours, the multilayer structure 211 of the other battery cells did not warp.

[0196] Comparative Example 4 shows that after the 10 battery cells were prepared, the multilayer structure 211 of each of the 10 battery cells did not immediately show the problem of warping. However, after being stored at 85°C for 24 hours, the multilayer structure 211 of 6 of the battery cells showed the problem of warping.

[0197] In some embodiments, the second adhesive layer 242 includes an adhesive layer formed by coating.

[0198] When the second adhesive layer 242 includes a coated adhesive layer, the thickness of the second adhesive layer 242 can be designed to be thinner, which can reduce material costs on the one hand and help improve the appearance of the battery cell on the other.

[0199] In some embodiments, the thickness of the adhesive layer formed by coating is from 0.5 micrometers to 20 micrometers.

[0200] If the thickness of the adhesive layer formed by casting is less than 0.5 micrometers, the adhesive force provided by the second adhesive layer 242 may be weak, failing to guarantee a reliable connection between the folded edges 210 of each layer in the multilayer structure 211, and there is still a risk of peeling. If the thickness of the adhesive layer formed by casting is greater than 20 micrometers, it will not only increase material costs, but may also lead to a decrease in the adhesive strength of the adhesive layer.

[0201] To avoid the above problems, this embodiment limits the thickness of the coated adhesive layer to 0.5 micrometers to 20 micrometers, which can ensure a reliable connection between the folded edges 210 of each layer in the multilayer structure 211 and also help reduce material costs.

[0202] When the second adhesive layer 242 includes a coated adhesive layer, the effects it can achieve can be demonstrated by the following data.

[0203] Example 5

[0204] This embodiment provides a battery cell where the width of the folded edge 210 of the insulating film 200 is 1 mm. A second adhesive layer 242 is coated and formed at least in the multilayer structure 211 of the folded edge 210. The material of the second adhesive layer 242 can be an ethylene-vinyl acetate copolymer (EVA) adhesive layer, and the thickness of the second adhesive layer 242 can be 10 μm. After attaching the top patch 400 to the cover plate assembly 300, a hot-pressing process is performed on the location of the second adhesive layer 242, with process parameters of 150°C for 4 seconds.

[0205] Example 6

[0206] Example 6 provides a battery cell that differs from Example 5 only in that the width of the folded edge 210 is 3mm.

[0207] Example 7

[0208] Example 7 provides a battery cell that differs from Example 5 only in that the width of the folded edge 210 is 5 mm.

[0209] Comparative Example 5

[0210] Comparative Example 5 provides a battery cell that differs from Example 5 only in that a second adhesive layer 242 is not formed on the insulating film 200.

[0211] Comparative Example 6

[0212] Comparative Example 6 provides a battery cell that differs from Example 6 only in that a second adhesive layer 242 is not formed on the insulating film 200.

[0213] Comparative Example 7

[0214] Comparative Example 7 provides a battery cell that differs from Example 7 only in that a second adhesive layer 242 is not formed on the insulating film 200.

[0215] Ten cells of each of the battery cells provided in Examples 5, 6, 7, 5, 6, and 7 were tested, and the experimental data are shown in Table 2.

[0216] Table 2 Test Data

[0217]

[0218] As can be seen from Table 2, Examples 5, 6, and 7 show that after storage at 85°C for 24 hours, no warping problem occurred in the multilayer structure 211 of all battery cells. This indicates that when the second adhesive layer 242 includes a cast adhesive layer, warping will not occur in the multilayer structure 211 regardless of whether the width of the folded edge 210 is large or small.

[0219] Comparative Example 5 shows that after the 10 battery cells were prepared, the multilayer structure 211 of each of the 10 battery cells immediately showed the problem of warping. At this time, it was no longer necessary to carry out the experiment described in the second column of "storing at 85°C for 24 hours" to count the number of battery cells with warping of multilayer structure 211.

[0220] Comparative Example 6 shows that after the 10 battery cells were prepared, the multilayer structure 211 of 4 of the battery cells had warping problems. After being stored at 85°C for 24 hours, the multilayer structure 211 of 2 more battery cells had warping problems.

[0221] Comparative Example 7 shows that after the 10 battery cells were prepared, the multilayer structure 211 of each of the 10 battery cells did not immediately show any warping problem. However, after being stored at 85°C for 24 hours, the multilayer structure 211 of 5 of the battery cells showed warping problem.

[0222] In some embodiments, the material of the second adhesive layer 242 is at least one selected from ethylene methyl acrylate copolymer (EMA), anhydride-modified ethylene methyl acrylate copolymer (EMA-AA), ethylene methacrylate copolymer (E-MAA-AA), ethylene acrylate copolymer (EAA), polyethersulfone resin, polyethylene (PE), polypropylene (PP), ethylene vinyl acetate copolymer (EVA), polyamide (PA), polylactic acid (PLA), and polyester.

[0223] It should be noted that when the second adhesive layer 242 includes a cast adhesive layer, it can be an ethylene and its copolymer hot melt adhesive layer (including ethylene methyl acrylate copolymer EMA, anhydride-modified ethylene methyl acrylate copolymer, ethylene methacrylate copolymer E-MAA-AA, ethylene acrylate copolymer EAA), or a polyethersulfone resin PES hot melt adhesive layer.

[0224] When the second adhesive layer 242 includes a coated adhesive layer, it can be a polyolefin hot melt adhesive layer (including polyethylene PE and polypropylene PP, etc.), an ethylene and its copolymers hot melt adhesive layer (ethylene vinyl acetate copolymer EVA, etc.), a polyamide PA hot melt adhesive layer, a polylactic acid PLA hot melt adhesive layer, or a polyester hot melt adhesive layer, etc.

[0225] Figure 20 A top view schematic diagram of a battery cell with an open end 110 is shown.

[0226] like Figure 1 and Figure 20 In some embodiments, a plate assembly 320 is mounted on the surface of the cover body 310, the plate assembly 320 including at least one of a terminal post 321 and an explosion-proof valve 322; the width of the folded edge 210 is W1; the cover body 310 is along the thickness direction of the battery cell (e.g., ... Figure 17 The dimension of the panel assembly 320 in the Y direction is W2; the maximum dimension of the panel assembly 320 in the thickness direction of the battery cell is W3; the ratio of W1 to (W2-W3) / 2 is x, 0.2≤x≤1.

[0227] For example, in combination Figure 20 The structure and orientation shown are illustrated with an example of a panel assembly 320 consisting only of a terminal post 321 and an explosion-proof valve 322. When the dimension of the terminal post 321 along the thickness direction of the battery cell (hereinafter referred to as longitudinal) is greater than the longitudinal dimension of the explosion-proof valve 322, W3 is the longitudinal dimension of the terminal post 321. When the longitudinal dimension of the terminal post 321 is less than the longitudinal dimension of the explosion-proof valve 322, W3 is the longitudinal dimension of the explosion-proof valve 322.

[0228] For example, (W2-W3) / 2 is the minimum distance between the edge of the cover body 310 and the edge of the adjacent panel assembly 320 along the thickness direction of the battery cell.

[0229] For example, 0.8 ≤ x ≤ 0.95.

[0230] If the ratio x is too large, the insulating film 200 exceeding the cover body 310 may interfere with the panel assembly 320 (e.g., pole post 321 and / or explosion-proof valve 322) after bending towards the cover body 310, which will have an adverse effect on the connection reliability between the insulating film 200 and the cover body 310, the insulation performance of the battery cell, and the appearance of the battery cell.

[0231] If the ratio x is too small, the width of the folded edge 210 will be too small. As a result, the effective connection area between two adjacent folded edges 210 in the multi-layer structure 211 will also be small. The tension generated between two adjacent folded edges 210 may not be enough to maintain a reliable connection between the two folded edges 210. Over time, the two adjacent folded edges 210 may still separate to a certain extent, causing the multi-layer structure 211 to warp.

[0232] To avoid the above problems, this embodiment can design the ratio x to be 0.2≤x≤1. On the one hand, it can ensure that each adjacent two layers of folded edge portions 210 in the multilayer structure 211 form a reliable connection, preventing the multilayer structure 211 from warping. On the other hand, it can also ensure that the folded edge portion 210 connected to the surface of the cover plate body 310 will not interfere with the plate assembly 320, ensuring that the folded edge portion 210 and the cover plate body 310 are reliably connected, which helps to improve the insulation performance and appearance quality of the battery cell.

[0233] like Figure 1 and Figure 20 In some embodiments, the folded edge portion 210 is spaced apart from the panel assembly 320, and the minimum distance between the folded edge portion 210 and the panel assembly 320 is L1, where 0.5mm≤L1≤4mm.

[0234] In actual production, dimensional and positional tolerances are unavoidable among the various components of a battery cell. If L1 is too small, the insulating film 200 exceeding the cover body 310 may interfere with the panel assembly 320 (e.g., terminal post 321 and / or explosion-proof valve 322) after bending towards the cover body 310, which will adversely affect the reliability of the connection between the insulating film 200 and the cover body 310, the insulation performance of the battery cell, and the appearance of the battery cell.

[0235] Since the surface dimensions of the cover plate body 310 are relatively fixed, if L1 is designed to be too large, it will result in the width of the folded edge 210 being too small, or the size of the panel assembly 320 being too small. The problems caused by the folded edge 210 being too small are the same as those mentioned above, and will not be repeated here. The size of the panel assembly 320 being too small will also have an adverse effect on the performance of the battery cells. For example, the size of the terminal post 321 being too small will have an adverse effect on the electrical performance and service life of the battery cells. The size of the explosion-proof valve 322 being too small will prevent the high-temperature gas generated inside the battery cell from being discharged in time during thermal runaway, posing a safety hazard.

[0236] To avoid the above problems, in this embodiment, L1 can be designed to be 0.5mm≤L1≤4mm. This ensures that the folded edge 210 connected to the surface of the cover plate body 310 will not interfere with the plate assembly 320, which helps to improve the insulation performance and appearance quality of the battery cell. It also ensures that the width of the folded edge 210 is reasonable, preventing the multi-layer structure 211 from warping. Furthermore, it ensures that the size of the plate assembly 320 is reasonable, thus guaranteeing the electrical performance, safety performance, and service life of the battery cell.

[0237] Figure 21 A top-view schematic diagram of a single battery cell with two open ends is shown. Figure 21Although the panel assembly 320 of the battery cell with two open ends 110 is not exactly the same as the panel assembly 320 of the battery cell with one open end 110, the way the size of the folded edge 210 is limited, and the beneficial effects that can be achieved by satisfying the size limit are the same, which will not be described again here.

[0238] like Figure 2 , Figure 17 and Figure 21 In some embodiments, the housing 100 has two open ends 110, which are located on opposite sides of the housing 100; the insulating film 200 has a dimension L along the height direction of the battery cell, and the height of the housing 100 is L2, where L < L2 + (W2 - W3).

[0239] For example, L > L2.

[0240] If L is too large, the insulating film 200 that exceeds the cover plate body 310 may interfere with the panel assembly 320 after bending towards the cover plate body 310, which will have an adverse effect on the connection reliability between the insulating film 200 and the cover plate body 310, the insulation performance of the battery cell, and the appearance of the battery cell.

[0241] If L is too small, the width of the folded edge 210 will be too small, and the multi-layer structure 211 will easily warp.

[0242] like Figure 20 and Figure 21 In some embodiments, the folded edge portion 210 includes a wide sub-portion 216 extending along the thickness direction of the battery cell and a long sub-portion 215 extending along a second direction; the second direction, the thickness direction of the battery cell, and the first direction are perpendicular to each other; at least one end of the wide sub-portion 216 has a wide fold line 2161 and a wide redundant sub-portion 2162 capable of being flipped around the wide fold line 2161, the wide fold line 2161 intersecting the edge of the cover plate body 310; at least one end of the long sub-portion 215 has a long fold line 2151 and a long redundant sub-portion 2152 capable of being flipped around the long fold line 2151, the long fold line 2151 intersecting the edge of the cover plate body 310; the wide redundant sub-portion 2162 is connected to the long redundant sub-portion 2152 and folded over the long sub-portion 215 or the wide sub-portion 216 to form a multilayer structure 211.

[0243] It should be noted that the formation process of the multilayer structure 211, and the relative positions of the multilayer structure 211 with the wide sub-section 216 and the long sub-section 215, are as described above. Figure 3 , Figure 4 and Figure 5 As shown, it will not be elaborated further here.

[0244] like Figure 20 and Figure 21 In some embodiments, the orthographic projection of the multilayer structure 211 onto the surface of the cover body 310 along the height direction of the battery cell is triangular.

[0245] The wide-direction redundant sub-part 2162 is connected to the long-direction redundant sub-part 2152, and after being folded along the long-direction fold line 2151 or the wide-direction fold line 2161, the resulting multi-layer structure 211 is triangular. Of course, in this embodiment, the triangle can have three straight lines or at least one curve; the intersection of the three lines of the triangle can form three vertices or at least one rounded corner.

[0246] In some embodiments, one apex of the triangle faces the direction of the center of the surface of the cover body 310.

[0247] Specifically, one vertex of the triangle is located on the line connecting the center of the triangle and the center of the surface of the cover plate body 310; or, one vertex of the triangle is located on the line connecting the center of the triangle and the center of the surface of the cover plate body 310, but deviates from the line connecting the two centers.

[0248] like Figure 20 and Figure 21 In some embodiments, the multilayer structure 211 is located near the edge of the cover body 310 along the thickness direction of the battery cell (i.e., the length edge of the cover body 310).

[0249] Understandably, regardless of whether the folded edge 210 in the multi-layer structure 211 is connected by adhesive or thermoforming, the thickness of the multi-layer structure 211 is usually greater than the thickness of the single-layer structure 212. Therefore, when a top patch 400 is connected above the folded edge 210, the multi-layer structure 211 may exert a pushing force on the top patch 400. If the distance between the two multi-layer structures 211 is small, the pushing force exerted by the two multi-layer structures 211 on the top patch 400 will be more concentrated, and the risk of the top patch 400 lifting will be correspondingly higher. Conversely, if the distance between the two multi-layer structures 211 is large, the pushing force exerted by the two multi-layer structures 211 on the top patch 400 will be more dispersed, and the risk of the top patch 400 lifting will be correspondingly lower.

[0250] Combination Figure 20 and Figure 21 It can be seen that regardless of whether the battery cell has one open end 110 or two open ends 110, the length edge dimension of the cover body 310 is larger than the width edge dimension. When the multilayer structure 211 is close to the length edge of the cover body 310, the spacing between two adjacent multilayer structures 211 will be larger. As mentioned above, this helps to enable the top patch 400 to achieve a reliable connection with the folded edge 210.

[0251] Based on the same inventive concept and in conjunction with the description of the battery cells in the above embodiments, this embodiment provides a battery that has the corresponding technical effects of the battery cells in the above embodiments, which will not be repeated here.

[0252] A battery comprising a battery cell as described in the various embodiments above.

[0253] It should be noted that some embodiments of this application have been described above. Other embodiments are within the scope of the appended claims.

[0254] The various embodiments in this application are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0255] The description in this application is given for illustrative purposes and is not intended to be exhaustive or to limit the application to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of this application and to enable those skilled in the art to understand this application and design various embodiments with various modifications suitable for a particular purpose.

[0256] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application is limited to these examples; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of this application as described above, which are not provided in detail for the sake of brevity.

[0257] Although this application has been described in conjunction with specific embodiments thereof, many substitutions, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description.

[0258] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. A battery cell, characterized in that, include: The housing has at least one open end; The cover plate body covers the opening end; An insulating film is applied to the housing; the portion of the insulating film extending beyond the cover body along the height direction of the battery cell is bent and fixed to the cover body, forming a folded edge; the folded edges are stacked in a portion of the cover body along the height direction of the battery cell to form a multi-layer structure, and adjacent layers of the folded edges in the multi-layer structure are interconnected.

2. The battery cell according to claim 1, characterized in that, The insulating film has a first surface and a second surface disposed opposite to each other, and the first surface is provided with a first adhesive layer. The multi-layer structure includes a first sub-part and a second sub-part. The first sub-part is connected to the surface of the cover plate body through the first adhesive layer. The second sub-part is located on the side of the first sub-part away from the cover plate body. The first surface of the second sub-part is opposite to the first surface of the first sub-part. At least a portion of the second sub-part and at least a portion of the first sub-part are fused together to form a fused structure.

3. The battery cell according to claim 2, characterized in that, The fusion structure is formed by N layers of the folded edge portion, the thickness of a single layer of the folded edge portion is H0, and the height difference between the top surface of the fusion structure and the surface of the cover plate body along the height direction of the battery cell is H1, 0 < H1 < N × H0.

4. The battery cell according to claim 2, characterized in that, The insulating film includes a first base layer, an inner adhesive layer, and a second base layer stacked sequentially. The surface of the first base layer away from the inner adhesive layer forms the first surface of the insulating film, and the surface of the second base layer away from the inner adhesive layer forms the second surface of the insulating film. The second base layer of the first sub-part is fused with the second base layer of the second sub-part to form a fused structure in the multi-layer structure.

5. The battery cell according to claim 2, characterized in that, The multi-layer structure further includes a third sub-part, which is located on the side of the second sub-part away from the cover plate body, and the first surface of the third sub-part faces the first surface of the second sub-part. The second base layer of the first sub-part is fused with the second base layer of the second sub-part, and the first adhesive layer disposed in the third sub-part is fused with the first adhesive layer disposed in the second sub-part, so that the multilayer structure forms a fused structure.

6. The battery cell according to claim 2, characterized in that, The second sub-part and the first sub-part are thermally pressed together to form the fused structure from the multilayer structure.

7. The battery cell according to claim 1, characterized in that, The surface of the cover plate body is equipped with a plate assembly, which includes at least one of an electrode post and an explosion-proof valve. The width of the folded edge is W1; the dimension of the cover plate body along the thickness direction of the battery cell is W2; the maximum dimension of the plate assembly along the thickness direction of the battery cell is W3. The ratio of W1 to (W2-W3) / 2 is x, where 0.2≤x≤1; or, The folded edge is spaced apart from the panel assembly, and the minimum distance between the folded edge and the panel assembly is L1, where 0.5mm≤L1≤4mm.

8. The battery cell according to claim 7, characterized in that, The housing has two openings, which are located on opposite sides of the housing. The dimension of the insulating film along the height direction of the battery cell is L, and the height of the casing is L2, where L < L2 + (W2 - W3).

9. The battery cell according to claim 1, characterized in that, The folded edge includes a wide sub-part extending along the thickness direction of the battery cell and a long sub-part extending along a second direction; the second direction, the thickness direction of the battery cell, and the height direction of the battery cell are perpendicular to each other. At least one end of the wide sub-part has a wide fold line, and a wide redundant sub-part that can be flipped around the wide fold line, the wide fold line intersecting the edge of the cover plate body; at least one end of the long sub-part has a long fold line, and a long redundant sub-part that can be flipped around the long fold line, the long fold line intersecting the edge of the cover plate body. The wide-axis redundant sub-part is connected to the long-axis redundant sub-part and folded over the long-axis sub-part or the wide-axis sub-part to form the multi-layer structure.

10. The battery cell according to claim 1 or 9, characterized in that, Along the height direction of the battery cell, the orthographic projection of the multilayer structure onto the surface of the cover plate body is triangular.

11. The battery cell according to claim 1, characterized in that, The battery cell further includes a top patch, which is located on the side of the folded edge away from the cover plate body and is connected to the cover plate body and / or the folded edge; along the height direction of the battery cell, the projection of the top patch and the folded edge on the cover plate body at least partially overlaps.

12. A battery, characterized in that, Includes the battery cell as described in any one of claims 1 to 11.

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