Insulating film and battery cell

Abstract

The utility model relates to the technical field of batteries, in particular to an insulating film and a battery cell. Folding marks are formed on the insulating film, the insulating film is folded along the folding marks to wrap the outer wall of the pole group, and the thickness size of the pole group is W; the folding marks comprise a first folding mark and a second folding mark which extend in the first direction, the first folding mark and the second folding mark are arranged at the two ends of the pole group in the thickness direction, the distance between the first folding mark and the second folding mark is L3, and L3 is larger than or equal to W-0. 5 and smaller than or equal to W + 0.5. According to the utility model, the assembling reliability of the insulating film and the pole group can be ensured, so that the pole group can be effectively wrapped by the insulating film, the insulativity of the pole group is ensured, the situation that the pole group is damaged due to difficult wrapping or the situation that the pole group enters a shell is influenced due to loose wrapped insulating film is avoided, and the production quality and the production efficiency of a battery cell are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to an insulating film and a battery core. Background Art

[0002] Lithium-ion batteries are currently widely used in various fields such as transportation power supply, power storage power supply, new energy storage power supply, aerospace and military industry, etc., due to their large capacity, high operating voltage, strong charge retention ability, and long cycle life. After the assembly of the pole group and the final welding of the pole ear, lithium-ion batteries are usually wrapped with a layer of insulating film on the outside of the pole group to separate the pole group and the shell, which plays an insulating role. If the insulating film wraps the pole group too tightly, it is easy to damage the pole group. If it is wrapped too loosely, it is easy to interfere with the entry of the pole group into the shell, thereby reducing production efficiency and production quality. Utility Model Content

[0003] In view of this, the purpose of the present application is to provide an insulating film and a battery cell to solve the problem that the insulating film and the electrode group are inconvenient to assemble in the existing production process, and it is easy to wrap them too tightly or too loosely, thereby damaging the electrode group, reducing the insulation performance of the electrode group, and affecting the production efficiency and production quality of the battery cell.

[0004] The first aspect of the utility model provides an insulating film, wherein a fold is formed on the insulating film, and the insulating film is folded along the fold so that it is wrapped around the outer wall of the electrode group, and the thickness of the electrode group is W;

[0005] The fold includes a first fold and a second fold extending along a first direction, the first fold and the second fold are arranged at two ends in the thickness direction of the pole group, the distance between the first fold and the second fold is L3, W-0.5≤L3≤W+0.5.

[0006] Preferably, the fold further includes a third fold and a fourth fold extending along the first direction, and the third fold and the fourth fold are respectively arranged at two ends of the insulating film in the second direction.

[0007] Preferably, the insulating film is provided with positioning holes at both ends in the second direction, the positioning holes comprising a first positioning hole and a second positioning hole provided between the third fold and an edge of the insulating film, and a third positioning hole and a fourth positioning hole provided between the fourth fold and another edge of the insulating film;

[0008] A line connecting any two of the first positioning hole, the second positioning hole, the third positioning hole and the fourth positioning hole is arranged at an angle to the second direction.

[0009] Preferably, in the first direction, the distance between the first positioning hole and the second positioning hole is A, and the distance between the third positioning hole and the fourth positioning hole is B; the size of the third positioning hole in the first direction is C, and the size of the fourth positioning hole in the first direction is D; A>B+C+D.

[0010] Preferably, a plurality of protruding wrapping portions are formed at both ends of the insulating film in the first direction, and the wrapping portions are folded so as to be arranged at both ends in the length direction of the pole group.

[0011] Preferably, the wrapping parts are symmetrically arranged with each other along the center line of the insulating film; the wrapping parts located on the same side of the center line extending along the first direction include a first wrapping part and a second wrapping part, the first wrapping part and the second wrapping part are arranged at both ends in the length direction of the pole ear, the distance between the first wrapping part and the second wrapping part in the second direction is L2, and the length dimension of the pole ear is L1, 2≤L2-L1≤0.5×L1.

[0012] Preferably, the dimension of the first wrapping portion in the first direction is L4, 0.5×L3+3≤L4≤L3;

[0013] And / or, a dimension of the second wrapping portion in the first direction is L5, 0.5×L3+3≤L5≤L3.

[0014] Preferably, a protruding sealing portion is formed at the end of the insulating film in the first direction, a gap is provided between the sealing portion and the wrapping portion in the second direction, and the sealing portion is folded so that it can overlap with at least a portion of the wrapping portion.

[0015] Preferably, the sealing portion is provided at an end portion of the insulating film in the second direction, and / or the sealing portion is provided between the first fold and the second fold in the second direction.

[0016] A second aspect of the utility model provides a battery core, comprising the insulating film described in any of the above technical solutions.

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

[0018] A crease is formed on the insulating film of the utility model, and the insulating film is folded along the crease so that it is wrapped around the outer wall of the electrode group, and the thickness of the electrode group is W; the crease includes a first crease and a second crease extending along a first direction, and the first crease and the second crease are arranged at two ends in the thickness direction of the electrode group, and the distance between the first crease and the second crease is limited to L3, W-0.5≤L3≤W+0.5, so as to ensure the reliability of the assembly of the insulating film and the electrode group, so that the insulating film can effectively wrap the electrode group, ensure the insulation of the electrode group, avoid the situation where the electrode group is damaged due to wrapping difficulties or the insulating film after wrapping is relatively loose and affects the entry of the electrode group into the shell, thereby improving the yield rate and production efficiency of the battery cell.

[0019] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A schematic diagram of the structure of the insulating film provided in the first embodiment of the utility model in an unfolded state;

[0022] Figure 2 A schematic diagram of the structure of the insulating film provided in the second embodiment of the utility model in the unfolded state;

[0023] Figure 3 A schematic diagram of the structure of the insulating film provided in the third embodiment of the present utility model in an unfolded state;

[0024] Figure 4 A schematic diagram of the structure of the insulating film provided in the fourth embodiment of the utility model in an unfolded state;

[0025] Figure 5 A schematic diagram of the structure of an electrode group wrapped by an insulating film provided in an embodiment of the utility model;

[0026] Figure 6 A schematic diagram of the assembly structure of the insulating film and the electrode group provided in an embodiment of the utility model;

[0027] Figure 7 A schematic diagram of the structure of the insulating film and the side plate in the battery cell provided in an embodiment of the utility model.

[0028] Icon: 10-insulating film; 101-first fold; 102-second fold; 103-third fold; 104-fourth fold; 105-fifth fold; 106-sixth fold; 111-first positioning hole; 112-second positioning hole; 113-third positioning hole; 114-fourth positioning hole; 12-wrapping part; 121-first wrapping part; 122-second wrapping part; 13-sealing part; 20-pole group; 21-pole ear; 30-side plate; D1-first direction; D2-second direction. DETAILED DESCRIPTION

[0029] The following specific embodiments are provided to help the reader obtain a comprehensive understanding of the methods, devices and / or systems described herein. However, after understanding the disclosure of the present application, various changes, modifications and equivalents of the methods, devices and / or systems described herein will be apparent. For example, the order of operations described herein is merely an example, and is not limited to the order set forth herein, but in addition to the operations that must occur in a particular order, changes that will be apparent after understanding the disclosure of the present application may be made. In addition, in order to improve clarity and brevity, descriptions of features known in the art may be omitted.

[0030] The features described herein may be implemented in different forms and should not be interpreted as being limited to the examples described herein. Rather, the examples described herein have been provided only to illustrate some of the many possible ways of implementing the methods, devices and / or systems described herein that will be apparent after understanding the disclosure of the present application.

[0031] Throughout the specification, when an element (such as a layer, a region, or a substrate) is described as being “on”, “connected to”, “bound to”, “over”, or “covering” another element, it may be directly “on”, “connected to”, “bound to”, “over”, or “covering” another element, or one or more other elements may be present between them. In contrast, when an element is described as being “directly on”, “directly connected to”, “directly bound to”, “directly over”, or “directly covering” another element, there may be no other elements present between them.

[0032] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more items.

[0033] Although terms such as "first," "second," and "third" may be used herein to describe various members, components, regions, layers, or portions, these members, components, regions, layers, or portions are not limited by these terms. Rather, these terms are only used to distinguish one member, component, region, layer, or portion from another member, component, region, layer, or portion. Therefore, without departing from the teachings of the examples described herein, the first member, component, region, layer, or portion referred to may also be referred to as the second member, component, region, layer, or portion.

[0034] For ease of description, spatial relational terms such as "above", "upper", "below", and "lower" may be used herein to describe the relationship of one element to another element as shown in the accompanying drawings. Such spatial relational terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, an element described as being "above" or "upper" relative to another element will subsequently be "below" or "lower" relative to the other element. Therefore, the term "above" includes both "above" and "below" orientations depending on the spatial orientation of the device. The device may also be positioned in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relational terms used herein will be interpreted accordingly.

[0035] The terms used herein are only used to describe various examples and are not used to limit the present disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms "include", "comprise" and "have" list the stated features, quantities, operations, components, elements and / or their combinations that exist, but do not exclude the existence or addition of one or more other features, quantities, operations, components, elements and / or their combinations.

[0036] Variations in the shapes shown in the drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the drawings but include variations in shapes that occur during manufacturing.

[0037] The features of the examples described herein may be combined in various ways that will be apparent after understanding the disclosure of the present application. In addition, although the examples described herein have various configurations, other configurations are possible as will be apparent after understanding the disclosure of the present application.

[0038] According to a first aspect of the present utility model, an insulating film 10 is provided.

[0039] Hereinafter, a specific structure of the insulating film 10 according to the present embodiment will be described.

[0040] Embodiment 1

[0041] In this embodiment, if Figure 1 , Figure 5 and Figure 6 As shown, the insulating film 10 is in the unfolded state. Figure 1 As shown, the insulating film 10 may be a Mylar insulating film made of polyester polymer material. A fold is formed on the insulating film 10, and the insulating film 10 is folded along the fold so that the insulating film 10 is wrapped around the outer wall of the electrode group 20. In this embodiment, as shown in FIG. Figure 5 As shown, the pole group 20 is formed into a rectangular block structure, and the pole group 20 has a length direction, a width direction and a thickness direction that are perpendicular to each other. The pole group 20 is provided with a pole ear 21 at the end in the length direction, and the pole ear 21 needs to be exposed when the insulating film 10 wraps the pole group 20, wherein the dimension of the pole group 20 in the thickness direction is W, that is, the thickness dimension of the pole group 20 is W, and the unit is mm.

[0042] Specifically, Figure 1 As shown, the first direction D1 and the second direction D2 are arranged perpendicular to each other and parallel to the plane where the insulating film 10 is located. The main body of the insulating film 10 is formed into a rectangular structure. The folds include a first fold 101 and a second fold 102 extending along the first direction D1. The first fold 101 and the second fold 102 are arranged at both ends of the electrode group 20 in the thickness direction. The distance between the first fold 101 and the second fold 102 is L3, that is, the distance between the first fold 101 and the second fold 102 in the second direction D2 is L3, W-0.5≤L3≤W+0.5, the unit is mm, so that the reliability of the assembly of the insulating film 10 and the electrode group 20 is ensured, so that the insulating film 10 can effectively wrap the electrode group 20, ensure the insulation of the electrode group 20, avoid the situation that the insulating film 10 wraps the electrode group 20 too tightly due to the small size of L3, thereby causing difficulty in wrapping and easy damage to the electrode group 20, and can avoid the situation that the insulating film 10 wraps the electrode group 20 too loosely due to the large size of L3, thereby causing difficulty in entering the shell of the electrode group 20.

[0043] like Figure 1 , Figure 5 and Figure 6 As shown, the area between the first fold 101 and the second fold 102 covers one end of the electrode group 20 in the width direction.

[0044] Furthermore, in this embodiment, if Figure 1As shown, the fold also includes a third fold 103 and a fourth fold 104 extending along the first direction D1. The third fold 103 and the fourth fold 104 are respectively arranged at the two ends of the insulating film 10 in the second direction D2. Specifically, the third fold 103 is arranged on the side of the first fold 101 away from the second fold 102, and the fourth fold 104 is arranged on the side of the second fold 102 away from the first fold 101.

[0045] like Figure 1 , Figure 5 and Figure 6 As shown, the area between the first fold 101 and the third fold 103 and the area between the second fold 102 and the fourth fold 104 respectively cover the two ends of the electrode group 20 in the thickness direction.

[0046] In this embodiment, if Figure 1 As shown, in the second direction D2, the third fold 103 and the fourth fold 104 have a spacing X with the edge of the insulating film 10, 0.5mm≤X≤10mm. The insulating film 10 is folded along the third fold 103 and the fourth fold 104 so that the two ends of the insulating film 10 in the second direction D2 at least partially overlap and cover the other end in the width direction of the electrode group 20.

[0047] In this embodiment, if Figure 1 As shown, the insulating film 10 is provided with positioning holes at both ends in the second direction D2, and the positioning holes include a first positioning hole 111 and a second positioning hole 112 provided between the third fold 103 and the edge of the insulating film 10, and a third positioning hole 113 and a fourth positioning hole 114 provided between the fourth fold 104 and the other edge of the insulating film 10; the first positioning hole 111 and the second positioning hole 112 are arranged at intervals along the first direction D1, and the third positioning hole 113 and the fourth positioning hole 114 are arranged at intervals along the first direction D1. The first positioning hole 111, the second positioning hole 112, the third positioning hole 113 and the fourth positioning hole 114 can all be formed into a circular through-hole structure, but the shape of the positioning hole is not limited thereto and can be set according to actual needs.

[0048] In the second direction D2, the first positioning hole 111, the second positioning hole 112, the third positioning hole 113 and the fourth positioning hole 114 are arranged alternately with each other, that is, the line connecting any two of the first positioning hole 111, the second positioning hole 112, the third positioning hole 113 and the fourth positioning hole 114 is arranged at an angle to the second direction D2, so that after the insulating film 10 is folded along the third crease 103 and the fourth crease 104, the first positioning hole 111 does not intersect or overlap with the third positioning hole 113 and the second positioning hole 112 does not intersect or overlap with the fourth positioning hole 114, so as to avoid the situation in which the battery cell shell is corroded due to the falling of the electrode powder during the operation of the battery cell.

[0049] like Figure 1 As shown, in the first direction D1, the distance between the first positioning hole 111 and the second positioning hole 112 is A, and the distance between the third positioning hole 113 and the fourth positioning hole 114 is B; the size of the third positioning hole 113 in the first direction D1 is C, and the size of the fourth positioning hole 114 in the first direction D1 is D, and the unit of A, B, C or D is mm; in a preferred embodiment, A>B+C+D, so as to ensure that after the insulating film 10 is folded along the third crease 103 and the fourth crease 104, the first positioning hole 111 does not overlap with the third positioning hole 113 and the second positioning hole 112 does not intersect or overlap with the fourth positioning hole 114, thereby improving the reliability of avoiding the situation in which the battery cell shell is corroded due to powder falling of the electrode during the operation of the battery cell.

[0050] Furthermore, in this embodiment, if Figure 1 As shown, the insulating film 10 is formed with a plurality of protruding wrapping portions 12 at both ends in the first direction D1, and each end is provided with a plurality of wrapping portions 12 spaced apart from each other. The fold also includes a fifth fold 105 and a sixth fold 106 extending along the second direction D2, and the fifth fold 105 or the sixth fold 106 is arranged between the wrapping portion 12 and the first fold 101.

[0051] Furthermore, if Figure 1 As shown, the wrapping portions 12 are symmetrically arranged along the center line of the insulating film 10. The center line of the insulating film includes Figure 1 The two dotted lines indicate the two portions located in the middle of the insulating film 10 and extending respectively along the first direction D1 and the second direction, and the two center lines intersect to form a cross structure. After the insulating film 10 is folded along the first crease 101 and the second crease 102, the wrapping portion 12 is folded along the fifth crease 105 and the sixth crease 106, so that the wrapping portions 12 located on both sides of the center line extending along the first direction D1 can overlap each other, so as to wrap the two ends of the electrode group 20 in the length direction.

[0052] The wrapping portion 12 located on the same side of the center line extending along the first direction D1 includes a first wrapping portion 121 and a second wrapping portion 122. The distance between the first wrapping portion 121 and the second wrapping portion 122 in the second direction D2 is L2, in mm. After the insulating film 10 wraps the pole group 20, the first wrapping portion 121 and the second wrapping portion 122 are respectively arranged at the two ends of the length direction of the pole ear 21 on the pole group 20. The length dimension of the pole ear 21 is L1, in mm, 2≤L2-L1≤0.5×L1. This avoids the situation where the difference between L1 and L2 is too small, which easily damages the pole ear 21, or even causes the pole ear 21 to tear, or avoids the situation where the difference between L1 and L2 is too large, so that the side area of ​​the wrapping portion 12 in the length direction of the pole group 20 is too small, which is not conducive to protecting the pole group 20 and cannot ensure the insulation performance of the pole group 20.

[0053] Preferably, if Figure 1 As shown, the size of the first wrapping portion 121 in the first direction D1 is L4, in mm, 0.5×L3+3≤L4≤L3; and / or the size of the second wrapping portion 122 in the first direction D1 is L5, in mm, 0.5×L3+3≤L5≤L3, so as to ensure that the wrapping portions 12 on both sides of the center line extending along the first direction D1 can effectively overlap each other, so as to achieve reliable wrapping of the two ends of the electrode group 20 in the length direction. It should be noted that L4 and L5 can be the same size or different sizes.

[0054] Embodiment 2

[0055] In this embodiment, if Figure 2 As shown, the similarities between Example 2 and Example 1 are no longer elaborated. The difference between Example 2 and Example 1 is that a protruding sealing portion 13 is formed at the end of the insulating film 10 in the first direction D1, and the sealing portion 13 is symmetrically arranged along the center line extending in the second direction D2. There is a gap between the sealing portion 13 and the wrapping portion 12 in the second direction D2, so that when the insulating film 10 is folded along the first fold 101 and the second fold 102, the sealing portion 13 and the wrapping portion 12 are located on different sides of the electrode group 20, and the sealing portion 13 is folded along the fifth fold 105 and the sixth fold 106 so that it can overlap with at least part of the wrapping portion 12, so that the end of the electrode group 20 in the width direction is sealed, thereby improving the insulation performance of the insulating film 10.

[0056] Specifically, in this embodiment, Figure 2 As shown, the sealing portion 13 is disposed between the first fold 101 and the second fold 102 in the second direction D2 . After the insulating film 10 wraps the electrode group 20 , the sealing portion 13 is located at one end of the electrode ear 21 in the length direction.

[0057] Embodiment 3

[0058] In this embodiment, if Figure 3 As shown, the similarities between Example 3 and Example 2 are no longer elaborated. The difference between Example 3 and Example 2 is that the sealing portion 13 is arranged at the end of the insulating film 10 in the second direction D2, and preferably the sealing portion 13 is distributed at the four corners of the insulating film 10, so that when the insulating film 10 is folded along the third fold 103 and the fourth fold 104, the sealing portion 13 and the wrapping portion 12 are located on different sides of the pole group 20, and the sealing portions 13 located at both ends in the second direction D2 can be connected to each other, and the sealing portion 13 is folded along the fifth fold 105 and the sixth fold 106 so that it can overlap with at least part of the wrapping portion 12. After the insulating film 10 wraps the pole group 20, the sealing portion 13 is located at the other end in the length direction of the pole ear 21, so that the other side end of the pole group 20 in the width direction is sealed, thereby improving the insulation performance of the insulating film 10.

[0059] Embodiment 4

[0060] In this embodiment, if Figure 4 As shown, the similarities between Example 4 and Example 2 are no longer elaborated. The difference between Example 4 and Example 2 is that a sealing portion 13 is provided at the end of the insulating film 10 in the second direction D2 and between the first fold 101 and the second fold 102 in the second direction D2, and there is a gap between the sealing portion 13 and the wrapping portion 12 in the second direction D2, so that when the insulating film 10 is folded along the first fold 101, the second fold 102, the third fold 103 and the fourth fold 104, the sealing portion 13 and the wrapping portion 12 are located on different sides of the electrode group 20, and the sealing portion 13 is folded along the fifth fold 105 and the sixth fold 106 so that it can overlap with at least part of the wrapping portion 12, so that the two ends of the electrode group 20 in the width direction are sealed, thereby improving the insulation performance of the insulating film 10.

[0061] According to an insulating film provided by the utility model, a crease is formed on the insulating film, and the insulating film is folded along the crease so that it is wrapped around the outer wall of the pole group, and the thickness of the pole group is W; the crease includes a first crease and a second crease extending along a first direction, and the first crease and the second crease are arranged at two ends in the thickness direction of the pole group, and the distance between the first crease and the second crease is limited to L3, W-0.5≤L3≤W+0.5, so that the reliability of the assembly of the insulating film and the pole group is ensured, so that the insulating film can effectively wrap the pole group, ensure the insulation of the pole group, and avoid the situation where the pole group is damaged due to wrapping difficulties or the insulating film after wrapping is relatively loose and affects the entry of the pole group into the shell.

[0062] A second aspect of the utility model provides a battery core, comprising the insulating film as described above.

[0063] In an alternative embodiment, Figure 7 As shown, the battery cell further includes a side plate 30 for fixing, and the side plate 30 can be arranged inside the insulating film 10, that is, between the insulating film 10 and the electrode group, or outside the insulating film 10, that is, between the insulating film 10 and the shell. In other optional embodiments, no side plate is provided.

[0064] According to a battery cell provided by the utility model, the insulating film can completely wrap the electrode group without difficulty in wrapping or loose wrapping of the insulating film, thereby avoiding damage to the electrode group and ensuring that the battery cell is smoothly shelled, thereby improving the yield rate and production efficiency of the battery cell.

[0065] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The protection scope of the present application is not limited thereto. Although the present application is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed in the present application, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. An insulating film, characterized in that: A fold is formed on the insulating film, and the insulating film is folded along the fold so as to wrap around the outer wall of the electrode group, and the thickness of the electrode group is W; The fold includes a first fold and a second fold extending along a first direction, the first fold and the second fold are arranged at two ends in the thickness direction of the pole group, the distance between the first fold and the second fold is L3, W-0.5≤L3≤W+0.

5.

2. The insulating film according to claim 1, wherein The folds further include a third fold and a fourth fold extending along the first direction, and the third fold and the fourth fold are respectively arranged at two ends of the insulating film in the second direction.

3. The insulating film according to claim 2, characterized in that The insulating film is provided with positioning holes at both ends in the second direction, the positioning holes including a first positioning hole and a second positioning hole provided between the third fold and an edge of the insulating film, and a third positioning hole and a fourth positioning hole provided between the fourth fold and another edge of the insulating film; A line connecting any two of the first positioning hole, the second positioning hole, the third positioning hole and the fourth positioning hole is arranged at an angle to the second direction.

4. The insulating film according to claim 3, characterized in that In the first direction, the distance between the first positioning hole and the second positioning hole is A, and the distance between the third positioning hole and the fourth positioning hole is B; the size of the third positioning hole in the first direction is C, and the size of the fourth positioning hole in the first direction is D; A>B+C+D.

5. The insulating film according to claim 1, wherein A plurality of protruding wrapping portions are formed at two ends of the insulating film in the first direction, and the wrapping portions are folded so as to be arranged at two ends in the length direction of the pole group.

6. The insulating film according to claim 5, characterized in that The wrapping parts are symmetrically arranged with each other along the center line of the insulating film; the wrapping parts located on the same side of the center line extending along the first direction include a first wrapping part and a second wrapping part, the first wrapping part and the second wrapping part are arranged at both ends in the length direction of the pole ear, the distance between the first wrapping part and the second wrapping part in the second direction is L2, and the length dimension of the pole ear is L1, 2≤L2-L1≤0.5×L1.

7. The insulating film according to claim 6, characterized in that The dimension of the first wrapping portion in the first direction is L4, 0.5×L3+3≤L4≤L3; And / or, a dimension of the second wrapping portion in the first direction is L5, 0.5×L3+3≤L5≤L3.

8. The insulating film according to claim 5, characterized in that A protruding sealing portion is formed at the end of the insulating film in the first direction, a gap is provided between the sealing portion and the wrapping portion in the second direction, and the sealing portion is folded so that it can overlap with at least a portion of the wrapping portion.

9. The insulating film according to claim 8, characterized in that The sealing portion is provided at an end portion of the insulating film in the second direction, and / or the sealing portion is provided between the first fold and the second fold in the second direction.

10. A battery cell, characterized in that: The insulating film comprises the insulating film according to any one of claims 1 to 9.

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