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 covering the open end; and an insulating film covering 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. An adhesive layer connects adjacent folded edges in the multi-layer structure. The battery cell and battery provided by this application, by adding an adhesive layer to the multi-layer structure, achieve a reliable and tight connection between the folded edges of each layer. This not only prevents problems such as warping, folding, or damage to the insulating film but also ensures 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] The insulating film has two opposing surfaces, one of which has an adhesive layer (hereinafter referred to as the adhesive side), and the other surface does not have an adhesive layer (hereinafter referred to as the non-adhesive side). The insulating film is connected to the housing through the adhesive side. After the insulating film covers the housing, the portion extending beyond the housing opening can be bent towards the cover assembly and connected to the cover assembly through the adhesive side to form a folded edge. However, the folded edge is prone to warping or damage, affecting the insulation performance of the battery cell. 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; an insulating film covering the housing; wherein a portion of the insulating film extending beyond the cover plate body along the thickness direction 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 thickness direction to form a multilayer structure, wherein an adhesive layer connects each adjacent pair of folded edges in the multilayer structure.

[0006] 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.

[0007] Optionally, the second adhesive layer is disposed only in the multilayer structure.

[0008] Optionally, the second adhesive layer is also disposed in at least a portion of the folded edge, excluding the multilayer structure.

[0009] Optionally, the second adhesive layer is disposed on the entire second surface.

[0010] 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 defined as the width of the folded edge. 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.

[0011] 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 thickness direction of the cover plate body, the projection of the top patch and the folded edge on the cover plate body at least partially overlaps.

[0012] Optionally, the second adhesive layer includes a hot melt adhesive layer; or, 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 copolymer, polyethersulfone resin, polyethylene, polypropylene, ethylene methyl acrylate copolymer, polyamide, polylactic acid, and polyester.

[0013] Optionally, the second adhesive layer comprises a cast adhesive layer; or, the second adhesive layer comprises a coated adhesive layer; or, the second adhesive layer comprises a cast adhesive layer with a thickness of 5 micrometers to 30 micrometers; or, the second adhesive layer comprises a coated adhesive layer with a thickness of 0.5 micrometers to 20 micrometers; or, the insulating film has a thickness of 50 micrometers to 150 micrometers.

[0014] 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.

[0015] As can be seen from the above, the battery cell and battery provided in this application, by adding an adhesive layer to the multi-layer structure formed by the insulating film, can achieve a reliable and tight connection between the folded edges of each layer of the multi-layer structure through the adhesive layer. This not only prevents problems such as warping, folding or damage of 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 and ensuring that the battery cell has good insulation performance. Attached Figure Description

[0016] 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.

[0017] Figure 1 This is a schematic diagram of a battery cell with a first structure according to an embodiment of this application;

[0018] Figure 2 This is a schematic diagram of a battery cell with a second structure according to an embodiment of this application;

[0019] 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.

[0020] Figure 4 This is a partial schematic diagram of the process of connecting the battery cell to the cover plate body in an embodiment of this application;

[0021] 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.

[0022] Figure 6 for Figure 5 Schematic diagram of the cross-section BB in the middle;

[0023] 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;

[0024] Figure 8 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;

[0025] Figure 9 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.

[0026] Figure 10 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.

[0027] Figure 11 This is a schematic diagram of a battery cell with a fifth structure according to an embodiment of this application;

[0028] Figure 12 This is a schematic diagram of a battery cell with a sixth structure according to an embodiment of this application.

[0029] Explanation of reference numerals in the attached figures:

[0030] 100. Shell; 110. Open end;

[0031] 200, Insulating film; 210, Folded edge; 211, Multilayer structure; 2111, First sub-part; 2112, Second sub-part; 2113, Third sub-part; 212, Single-layer structure; 213, Double-layer structure; 220, First surface; 230, Second surface; 240, Adhesive layer; 241, First adhesive layer; 242, Second adhesive layer;

[0032] 300. Cover plate assembly; 310. Cover plate body; 320. Pole post; 330. Explosion-proof valve;

[0033] 400, Top patch; 410, Cutout area. Detailed Implementation

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] As is known from the background art, an insulating film is wrapped around the outer surface of the battery cell to achieve insulation. 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 addressing 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 adhesive-free surfaces 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, adversely affecting 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, thereby improving insulation performance.

[0041] 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 320 (including a positive terminal and a negative terminal) and an explosion-proof valve 330 connected to the cover body 310. The cover body 310 covers the opening 110.

[0042] For example, the cover body 310 and the housing 100 can be connected by welding.

[0043] 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 extending along the length of the housing 100 (e.g., ...). Figure 2 The cover plate assemblies are arranged relative to each other in the X 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 320 (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 330.

[0044] Regardless of whether it is the battery cell with the first structure or the battery cell with the second structure described above, the outer surface of the casing 100 is covered with an insulating film 200. 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 thickness direction of the cover plate body 310 (e.g., Figure 1 The part extending beyond the opening end 110 in the Z direction (hereinafter referred to as the first direction) can be connected to the cover plate body 310 after bending and is constructed as a folded edge 210.

[0045] Specifically, Figure 3 A partial schematic diagram is shown when the insulating film 200 extending beyond the opening end 110 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.

[0046] 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.

[0047] 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 opening end 110 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.

[0048] 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 a single-layer structure 212 of the folded edge portion 210. At this time, the adhesive side of the longitudinal portion is adhered to the surface of the cover plate body 310, and the non-adhesive side ( Figure 4 The central cross pattern portion faces upwards. It should be noted that at this point, the longitudinal portion will have a sub-part extending beyond the width edge of the cover plate body 310 (i.e., Figure 4 Part A of the sub-part will connect with the adhesive surface of the width part to form an overlapping area of ​​the length part and the width part (hereinafter referred to as the overlapping area).

[0049] 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 5After connecting the longitudinal portion to the cover plate body 310, the lateral portion can be folded along the width edge of the cover plate body 310 and applied to the surface of the cover plate body 310. At this time, the overlapping area will be folded toward the adhesive-free surface of the longitudinal portion, forming a multi-layered structure 211 there, and a single-layered structure 212 formed on both sides of the multi-layered structure 211 along the edge of the cover plate body 310.

[0050] 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 a single-layer structure 212 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. At this time, the overlapping area will be folded toward the adhesive-free surface of the wide portion, and a similar multi-layer structure 211 and single-layer structure 212 will be formed there.

[0051] In addition, the portion of the insulating film 200 that connects the longitudinal and lateral portions, i.e., the portion of the insulating film 200 near one corner of the cover plate body 310, can be bonded together to form a two-layer structure. Then, the longitudinal and lateral portions of the insulating film 200 can be applied to the surface of the cover plate body 310. Finally, the two-layer structure can be folded toward the lateral or longitudinal portion to form the aforementioned multi-layer structure 211.

[0052] Figure 6 Showing Figure 5 A schematic diagram of the cross-section BB in the middle section. Figure 6 The multilayer structure 211 includes a first sub-part 2111 and a second sub-part 2112 formed by the longitudinal portion of the insulating film 200, and a third sub-part 2113 formed by the wide portion. 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.

[0053] 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 structures shown are only for clearly demonstrating the specific structures of the multi-layer structure 211 and the single-layer structure 212, and are not intended to define the relative positions between the single-layer structure 212 and the multi-layer structure 211.

[0054] 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.

[0055] like Figure 1 The width of the folded edge 210 is L. The aforementioned warping problem is particularly noticeable when the width L 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.

[0056] To avoid the above problems, this application provides a single battery cell.

[0057] 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 edge 210 is stacked along the first direction in a portion of the cover body 310 to form a multilayer structure 211, and an adhesive layer 240 is connected between each two adjacent folded edge portions 210 in the multilayer structure 211.

[0058] 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.

[0059] For example, the adhesive layer 240 can be a hot melt adhesive layer or a pressure-sensitive adhesive layer.

[0060] 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.

[0061] For example, the folded edge 210 can be glued to the surface of the cover plate body 310.

[0062] 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 enables reliable connection between each folded edge 210 in the multilayer structure 211, thereby preventing separation between any two folded edges 210 in the multilayer structure 211 and thus avoiding warping of the insulating film 200.

[0063] The battery cell provided in this application embodiment adds an adhesive layer 240 to the multilayer structure 211 formed by the insulating film 200, so that the folded edges 210 of each layer of the multilayer structure 211 can be reliably and tightly connected through the adhesive layer 240. This not only prevents problems such as warping, folding or damage of the insulating film 200, but also ensures that the structural components connected to the insulating film 200 can form a reliable connection with the insulating film 200, thereby improving the appearance of the battery cell and ensuring that the battery cell has good insulation performance.

[0064] like Figure 1 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 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.

[0065] For example, 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 first sub-part 2111, and the first surface 220 of the third sub-part 2113 is opposite to the first surface 220 of the second sub-part 2112. The third sub-part 2113 and the second sub-part 2112 are connected by a first adhesive layer 241.

[0066] 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.

[0067] For example, the first adhesive layer 241 may 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 may be the same as or different from the type, formation method and material of the second adhesive layer 242.

[0068] The insulating film 200 can be adhesively bonded to the housing 100 and the cover plate body 310 through the first adhesive layer 241.

[0069] by Figure 7Taking the structure and orientation shown as an example, the folded edge portion 210 of the insulating film 200 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 both 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 adhesively connected to the first sub-part 2111 through the second adhesive layer 242.

[0070] 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 problems) to the multilayer structure 211. For example... Figure 4 The second adhesive layer 242 can be disposed in a portion of the A region, or in all of the A region, or in other parts of the folded edge 210 except for the multi-layer structure 211 (e.g., the single-layer structure 212).

[0071] In some embodiments, the second adhesive layer 242 is disposed only in the multilayer structure 211.

[0072] by Figure 4 Taking the structure shown as an example, the second adhesive layer 242 can be disposed in region A. By disposing of the second adhesive layer 242 only within 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 within 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.

[0073] 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.

[0074] Figure 8 The fourth type of battery cell structure was demonstrated. Figure 5 Schematic diagram of the cross section BB in the middle.

[0075] like Figure 8In 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.

[0076] 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.

[0077] Combination Figure 1 It 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.

[0078] 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.

[0079] Specifically, Figure 9 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 9 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.

[0080] Combination Figure 1 and Figure 9 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.

[0081] Similarly, Figure 10 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.

[0082] 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.

[0083] In some embodiments, the second adhesive layer 242 is disposed on the entire second surface 230.

[0084] 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.

[0085] 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.

[0086] like Figure 1 and Figure 7 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 L 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 L of the folded edge 210.

[0087] 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 320, the explosion-proof valve 330, or the injection hole.

[0088] 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 relatively 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 330 or the injection hole connected to the cover plate body 310, for example, it may hinder the opening of the explosion-proof valve 330 or block the injection hole.

[0089] 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 L 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.

[0090] It should also be noted that for insulating films 200 with a larger folded edge 210, the single-layer structure 212 formed in the wider direction has a larger area connected to the cover plate body 310 through the first adhesive layer 241, resulting in a larger restraining force on the multi-layer 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 plate assembly 300 does not have enough space for the insulating film 200 to form a wider folded edge 210. Correspondingly, the restraining force on the multi-layer structure 211 is also smaller. Therefore, it is necessary to set a wider second adhesive layer 242 on the folded edge 210 to prevent the insulating film 200 from lifting.

[0091] Figure 11 A schematic diagram of the fifth type of battery cell is shown.

[0092] like Figure 11 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.

[0093] 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 320, the explosion-proof valve 330 and the liquid injection hole connected to the cover plate body 310. It can also be used to identify the positive and negative terminals of the battery cells.

[0094] 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.

[0095] 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.

[0096] by Figure 11 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.

[0097] 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.

[0098] Figure 11 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.

[0099] Figure 12 A schematic diagram of the sixth type of battery cell is shown.

[0100] like Figure 12 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.

[0101] In some embodiments, the second adhesive layer 242 includes a hot melt adhesive layer.

[0102] For example, the melting point of the hot melt adhesive layer is between 50 and 200°C.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] In some embodiments, the second adhesive layer 242 includes a cast adhesive layer.

[0108] 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.

[0109] In some embodiments, the thickness of the insulating film 200 is 50 micrometers to 150 micrometers.

[0110] 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.

[0111] 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.

[0112] In some embodiments, the thickness of the adhesive layer formed by casting is 5 micrometers to 30 micrometers.

[0113] 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.

[0114] 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.

[0115] When the second adhesive layer 242 includes a cast adhesive layer, the effect it can achieve can be demonstrated by the following data.

[0116] Example 1

[0117] 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.

[0118] Example 2

[0119] Example 2 provides a battery cell that differs from Example 1 only in that the width of the folded edge 210 is 3mm.

[0120] Example 3

[0121] Example 3 provides a battery cell that differs from Example 1 only in that the width of the folded edge 210 is 5mm.

[0122] Comparative Example 1

[0123] Comparative Example 1 provides a battery cell that differs from Example 1 only in that a second adhesive layer 242 is not formed on the insulating film 200.

[0124] Comparative Example 2

[0125] 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.

[0126] Comparative Example 3

[0127] 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.

[0128] Ten cells of each of the battery cells provided in Examples 1, 2, 3, Comparative Examples 1, 2, and 3 were tested, and the experimental data are shown in Table 1.

[0129] Table 1 Test Data

[0130]

[0131] As can be seen from Table 1, Examples 1, 2, and 3 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.

[0132] Comparative Example 1 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.

[0133] Comparative Example 2 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.

[0134] Comparative Example 3 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.

[0135] In some embodiments, the second adhesive layer 242 includes an adhesive layer formed by coating.

[0136] 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.

[0137] In some embodiments, the thickness of the adhesive layer formed by coating is from 0.5 micrometers to 20 micrometers.

[0138] 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.

[0139] 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.

[0140] When the second adhesive layer 242 includes a coated adhesive layer, the effects it can achieve can be demonstrated by the following data.

[0141] Example 4

[0142] 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.

[0143] Example 5

[0144] Example 5 provides a battery cell that differs from Example 4 only in that the width of the folded edge 210 is 3mm.

[0145] Example 6

[0146] Example 6 provides a battery cell that differs from Example 4 only in that the width of the folded edge 210 is 5mm.

[0147] Comparative Example 4

[0148] 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.

[0149] Comparative Example 5

[0150] 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.

[0151] Comparative Example 6

[0152] 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.

[0153] Ten cells of each of the battery cells provided in Examples 4, 5, 6, 4, 5, and 6 were tested, and the experimental data are shown in Table 2.

[0154] Table 2 Test Data

[0155]

[0156] As can be seen from Table 2, Examples 4, 5, and 6 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.

[0157] Comparative Example 4 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.

[0158] Comparative Example 5 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.

[0159] Comparative Example 6 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 5 of the battery cells showed the problem of warping.

[0160] 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.

[0161] 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.

[0162] 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.

[0163] 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.

[0164] A battery comprising a battery cell as described in the various embodiments above.

[0165] It should be noted that some embodiments of this application have been described above. Other embodiments are within the scope of the appended claims.

[0166] 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.

[0167] 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.

[0168] 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.

[0169] 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.

[0170] 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: A housing having 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 plate body along the thickness direction 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 thickness direction to form a multi-layer structure, and an adhesive layer connects each adjacent pair of folded edges in the multi-layer structure.

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 adhesive layer includes a first adhesive layer disposed on the first surface and a second adhesive layer disposed on the second surface; 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, and the second surface of the second sub-part is 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.

3. The battery cell according to claim 2, characterized in that, The second adhesive layer is only provided in the multilayer structure.

4. The battery cell according to claim 2, characterized in that, The second adhesive layer is also disposed in at least a portion of the folded edge, excluding the multilayer structure.

5. The battery cell according to claim 2, characterized in that, The second adhesive layer is disposed on the entire second surface.

6. The battery cell according to claim 3 or 4, characterized in that, 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 defined as the width of the folded edge. 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.

7. The battery cell according to claim 1, 4, or 5, characterized in that, The battery cell also 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 connected to the folded edge. Along the thickness direction of the cover plate body, the projection of the top patch and the folded edge on the cover plate body at least partially overlaps.

8. The battery cell according to claim 2, characterized in that, The second adhesive layer includes a hot melt adhesive layer; or, The material of the second adhesive layer is at least one selected from ethylene vinyl acetate copolymer, acid 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.

9. The battery cell according to claim 2, characterized in that, The second adhesive layer comprises a cast adhesive layer; or, The second adhesive layer comprises a coated adhesive layer; or, The second adhesive layer comprises a cast adhesive layer, wherein the thickness of the cast adhesive layer is 5 micrometers to 30 micrometers; or, The second adhesive layer comprises a coated adhesive layer, wherein the thickness of the coated adhesive layer is from 0.5 micrometers to 20 micrometers; or, The thickness of the insulating film is 50 micrometers to 150 micrometers.

10. A battery, characterized in that, Includes the battery cell as described in any one of claims 1 to 9.

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