Battery cell insulating film and battery cell

Abstract

The present application relates to the technical field of batteries, and in particular to a battery cell insulating film and a battery cell. The battery cell insulating film comprises: a crease is formed on the battery cell insulating film; the battery cell insulating film is folded along the crease to wrap the outer wall of an electrode assembly; the battery cell insulating film is provided with through holes for allowing tab portions on the electrode assembly to pass through; the size of the through holes in a first direction is A, and the unit is mm; and the size of the tab portions in the first direction is A1, and the unit is mm; and 110%≤A / A1≤200%. The present application can avoid the impact of the excessively small size of the through holes on the assembly efficiency of the battery cell insulating film and the electrode assembly, and can also avoid the incapability of completely wrapping the electrode assembly by the battery cell insulating film due to the excessively large size of the through holes, so that the insulating performance and the assembly efficiency of the electrode assembly are improved, thereby improving the yield and production efficiency of the battery cell.

Description

Battery cell insulation film and battery cell

[0001] Cross-reference to related applications

[0002] The present application claims priority to the Chinese patent application No. CN202411379619.8, filed on September 30, 2024, and entitled "Battery cell insulation film and battery cell", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the technical field of batteries, in particular to a battery cell insulation film and a battery cell. BACKGROUND

[0004] Lithium ion batteries are widely used in various fields such as transportation power supply, power storage power supply, new energy storage power supply, aerospace and military due to their large capacity, high working voltage, strong charge retention ability, long cycle life and other advantages. After the assembly of the pole group and the final welding of the tab, a layer of insulation film is usually wrapped outside the pole group to separate the pole group and the shell. This plays an insulating role and can also prevent the pole group from being scratched by the shell during the shell insertion process. The insulation film can be a PP insulation film or a polyester high polymer insulation film. If the insulation film cannot be completely wrapped, the separator is easily damaged, which may cause the risk of insulation failure of the pole group. However, if the insulation film is overlapped or wound multiple times in order to increase the coverage area of the insulation film, it may also cause the pole group to thicken, which may lead to difficulties in shell insertion.

[0005] SUMMARY

[0006] Therefore, the purpose of the present application is to provide a battery cell insulation film and a battery cell to solve the problem of low wrapping efficiency of the insulation film in the existing production process, which cannot guarantee that the insulation film completely wraps the surface of the pole group and may easily cause damage to the separator, thereby reducing the insulation performance of the pole group.

[0007] In a first aspect, the present application provides a battery cell insulation film, wherein a fold is formed on the battery cell insulation film, and the battery cell insulation film is folded along the fold to wrap the outer wall of the pole group.

[0008] A through hole is formed on the battery cell insulation film to allow the tab part on the pole group to pass through.

[0009] The size of the through hole in the first direction is A, and the size of the tab part in the first direction is A1, both in mm; 110%≤A / A1≤200%.

[0010] Beneficial effects: by limiting the size relationship of A, A1, so as to avoid the size of the through hole being too small to affect the assembly efficiency of the cell insulation film and the pole group, and also avoid the size of the through hole being too large to cause the cell insulation film unable to completely wrap the pole group, thereby improving the insulation performance and assembly efficiency of the pole group, and further improving the yield and production efficiency of the cell.

[0011] In an alternative embodiment, the pole group comprises at least one pole group unit, at least part of the pole group unit is formed by winding the pole piece, the tabs on the pole group unit are gathered and connected to form the tab part, the size of the tab part in the second direction is B1, unit: mm; the size of the through hole in the second direction is B, unit: mm; 30%≤B / B1≤200%.

[0012] In an alternative embodiment, the pole group comprises at least one pole group unit, at least part of the pole group unit is formed by stacking a plurality of pole pieces, the size of the pole group unit in the second direction is B3, unit: mm; the size of the through hole in the second direction is B, unit: mm; 30%≤B / B3≤100%.

[0013] In an alternative embodiment, the fold comprises:

[0014] The first fold is formed into a linear structure extending along the second direction before folding;

[0015] The second fold is formed into a linear structure extending along the first direction before folding.

[0016] In an alternative embodiment, the distance between the first fold and the edge of the cell insulation film in the first direction is D;

[0017] When the pole group unit is formed by winding the pole piece, (0.5×N×B2+3)mm≤D≤(N×B2)mm, B2 is the size of the pole group unit in the second direction;

[0018] When the pole group unit is formed by stacking the pole piece, (0.5×N×B3+3)mm≤D≤(N×B3)mm;

[0019] N is the number of pole group units.

[0020] In an alternative embodiment, the distance between the second fold and the edge of the cell insulation film in the second direction is C;

[0021] When the pole group unit is formed by winding the pole piece, (0.5×N×B2+3)mm≤C≤(N×B2)mm, B2 is the size of the pole group unit in the second direction;

[0022] When the pole group unit is formed by stacking pole pieces, (0.5 x N x B3 + 3) mm ≤ C ≤ (N x B3) mm;

[0023] N is the number of the pole group units.

[0024] In an optional embodiment, an end of the first crease in the second direction is provided with an opening.

[0025] In an optional embodiment, the crease further comprises:

[0026] a third crease formed as a linear structure extending in the first direction; the third crease is arranged in the range of the area enclosed by the through hole and the second crease in the second direction.

[0027] In an optional embodiment, the through hole is provided with a plurality of through holes, and the plurality of through holes are arranged at intervals in the first direction.

[0028] In a second aspect, the application provides an electric core, comprising the electric core insulation film according to any one of the technical solutions. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the description of the embodiments or the prior art will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0030] Fig. 1 is a structural schematic diagram of the electric core insulation film in an unfolded state according to an embodiment of the present application;

[0031] Fig. 2 is a structural schematic diagram of the electric core insulation film in a folded state according to an embodiment of the present application, which is wrapped on the outer wall of a pole group;

[0032] Fig. 3 is a structural schematic diagram of the electric core insulation film in a folded state according to an embodiment of the present application, which is wrapped on the outer wall of a pole group from another perspective;

[0033] Fig. 4 is a structural schematic diagram of a pole group with a single pole group unit wrapped by the electric core insulation film according to an embodiment of the present application, wherein the pole group unit is formed by winding pole pieces;

[0034] Fig. 5 is a structural schematic diagram of a pole group with a plurality of pole group units wrapped by the electric core insulation film according to an embodiment of the present application, wherein the pole group units are formed by winding pole pieces;

[0035] Fig. 6 is a structural schematic diagram of a pole group with a single pole group unit wrapped by the electric core insulation film according to an embodiment of the present application, wherein the pole group unit is formed by stacking pole pieces;

[0036] FIG. 7 is a structural schematic diagram of a plurality of the pole group units each of which is covered by the insulating film of the battery cell and is formed by stacking the pole pieces, according to an embodiment of the present application.

[0037] Reference signs: 10-insulating film of battery cell; 100-through hole; 110-fold line; 111-first fold line; 112-second fold line; 113-third fold line; 120-opening; 20-pole group; 21-tab portion; 201-pole group unit; D1-first direction; D2-second direction. DETAILED DESCRIPTION

[0038] Embodiments of the present application are described in detail below with reference to the attached drawings, which show by way of example, embodiments in which the same or similar elements or elements having the same or similar functions are denoted with the same reference numerals throughout the drawings. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as limiting the present application.

[0039] The disclosure below provides many different embodiments or examples for implementing different structures of the present application. For the purpose of simplicity, the description of the specific examples below is described. Of course, they are merely examples and the purpose is not to limit the present application. In addition, the present application can repeatedly refer to the reference numerals and / or letters in different examples. Such repetition is for the purpose of simplification and clarity, and in itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those of ordinary skill in the art can realize the applicability of other processes and / or the use of other materials.

[0040] According to a first aspect of the present application, an insulating film 10 of a battery cell is provided.

[0041] In the following, the specific structure of the insulating film 10 of the battery cell according to the present embodiment will be described.

[0042] In the present embodiment, the insulating film 10 of the battery cell in the unfolded state is shown in FIG. 1, and the insulating film 10 of the battery cell can be an insulating film of PP material or a Mylar insulating film of polyester high molecular material. The insulating film 10 of the battery cell is formed with a fold line 110, and the insulating film 10 of the battery cell is folded along the fold line 110 so that the insulating film 10 of the battery cell covers the outer wall of the pole group 20, as shown in FIGS. 2 and 3, and the part of the insulating film 10 of the battery cell folded along the fold line 110 is overlapped to achieve closed covering of the pole group 20; the insulating film 10 of the battery cell is provided with a through hole 100 for the tab portion 21 on the pole group 20 to pass through, and the tab portion 21 is used to connect with the pole. The through hole 100 can be formed in a rectangular structure.

[0043] In an optional embodiment, a plurality of tab portions 21 are extended from the pole group 20, the tab portions 21 can be positive electrode tabs or negative electrode tabs, and the through holes 100 are correspondingly provided with a plurality of through holes, so that the tab portions 21 and the through holes 100 are one-to-one correspondingly arranged, and the plurality of through holes 100 are arranged at intervals along the first direction D1.

[0044] In the embodiment, as shown in FIGS. 1, 5 and 6, the size of the through hole 100 in the first direction D1 is A; the size of the tab portion 21 in the first direction D1 is A1, and 110%≤A / A1≤200%. In this way, the size of the through hole 100 is prevented from being too small to affect the assembly efficiency of the battery cell insulating film 10 and the pole group 20, and the size of the through hole 100 is also prevented from being too large to cause the battery cell insulating film 10 to be unable to completely wrap the pole group 20, thereby improving the insulation performance and assembly efficiency of the pole group 20, and further improving the yield and production efficiency of the battery cell.

[0045] In order to verify whether the limited condition of 110%≤A / A1≤200% can improve the assembly efficiency of the tab portion 21 and ensure the insulation of the pole group 20, different ratios of A / A1 are tested and detected, and the specific test results are shown in Table 1.

[0046] Table 1

[0047] As shown in FIGS. 4 and 5, the pole group 20 includes at least one pole group unit 201, at least part of the plurality of pole group units 201 are formed by winding the pole piece, and the tabs on the pole group unit 201 are gathered and connected to form the tab portion 21. The size of the tab portion 21 in the second direction D2 is B1, the unit of B1 is mm, the size of the through hole 100 in the second direction D2 is B, and 30%≤B / B1≤200%. It should be noted that the gathering and connection means that after the pole piece is wound, a plurality of tabs located at different positions are bent in a direction close to each other, so that two adjacent tabs are in contact, thereby gathering together to form the tab portion 21, and the plurality of tabs can be fixed by welding after gathering.

[0048] As shown in FIGS. 6 and 7, the pole group 20 includes at least one pole group unit 201, at least part of the plurality of pole group units 201 are formed by stacking a plurality of pole pieces, and the size of the pole group unit 201 in the second direction D2 is B3, the unit of B3 is mm, the size of the through hole 100 in the second direction D2 is B, the unit of B is mm, and 30%≤B / B3≤100%.

[0049] To verify whether the limited condition of 30%≤B / B1≤200% or 30%≤B / B3≤100% can further improve the assembly efficiency of the tab portion 21 and ensure the insulation of the pole group 20 on the basis of the limited condition of 110%≤A / A1≤200%, test detection is performed for different values of B / B1 and B / B3. For details, refer to Tables 2 and 3.

[0050] Table 2

[0051] Table 3

[0052] In the present embodiment, as shown in FIGS. 1-3, the crease 110 includes a first crease 111 and a second crease 112. The first crease 111 is formed into a linear structure extending along the second direction D2 before folding. The second crease 112 is formed into a linear structure extending along the first direction D1 before folding. In the present embodiment, the first direction D1 and the second direction D2 are perpendicular to each other, and the second direction D2 is the thickness direction of the pole group 20. The first crease 111 and the second crease 112 are preferably provided in two, respectively. The two first creases 111 are provided at two ends of the battery cell insulation film 10 in the first direction D1 and symmetrically relative to the center line of the battery cell insulation film 10 extending in the second direction D2. The two second creases 112 are provided at two ends of the battery cell insulation film 10 in the second direction D2 and symmetrically relative to the center line of the battery cell insulation film 10 extending in the first direction D1.

[0053] Further, in the present embodiment, as shown in FIG. 1, the distance between the first crease 111 and the edge of the battery cell insulation film 10 in the first direction D1 is D, with the unit of mm. As shown in FIGS. 4 and 5, when the pole group unit 201 is formed by winding, (0.5×N×B2+3)mm≤D≤(N×B2)mm, where B2 is the size of the pole group unit 201 in the second direction D2, and N is the number of the pole group units 201. As shown in FIGS. 6 and 7, when the pole group unit 201 is formed by stacking, (0.5×N×B3+3)mm≤D≤(N×B3)mm, where N is the number of the pole group units 201. In this way, the insulation of the pole group 20 can be further improved.

[0054] To verify whether the limited condition of (0.5×N×B2+3)mm≤D≤(N×B2)mm or (0.5×N×B3+3)mm≤D≤(N×B3)mm can further ensure that the battery cell insulation film 10 effectively wraps the pole group 20 and improve the insulation of the pole group 20, test detection is performed for two different cases of winding formation of the pole group unit 201 and stacking formation of the pole group unit 201. For details, refer to Tables 4 and 5.

[0055] Table 4

[0056] Table 5

[0057] Further, in the embodiment, as shown in FIG. 1, the distance C between the second crease 112 and the edge of the battery insulation film 10 in the second direction D2 is mm; as shown in FIG. 4 and FIG. 5, when the pole group unit 201 is formed by winding the pole piece, (0.5 x N x B2+3) mm≤C≤(N x B2) mm, B2 is the size of the pole group unit 201 in the second direction D2, and N is the number of the pole group units 201; as shown in FIG. 6 and FIG. 7, when the pole group unit 201 is formed by stacking the pole piece, (0.5 x N x B3+3) mm≤C≤(N x B3) mm, N is the number of the pole group units 201, which can further ensure the wrapping of the battery insulation film 10 to the pole group 20, thereby improving the insulation of the pole group 20.

[0058] In order to verify whether the limited condition (0.5 x N x B2+3) mm≤C≤(N x B2) mm or (0.5 x N x B3+3) mm≤C≤(N x B3) mm can further ensure the effective wrapping of the battery insulation film 10 to the pole group 20 and improve the insulation of the pole group 20, the test detection is carried out for the two different cases of the pole group unit 201 being formed by winding and the pole group unit 201 being formed by stacking, and the specific test results are shown in Table 6 and Table 7.

[0059] Table 6

[0060] Table 7

[0061] In addition, in the embodiment, as shown in FIG. 1, the end of the first crease 111 in the second direction D2 is provided with an opening 120, which can be formed into a triangular structure, so as to facilitate the folding of the battery insulation film 10 in the unfolded state along the crease 110 to fold the battery insulation film 10 into the rectangular structure shown in FIG. 2 and FIG. 3 to cover the outside of the pole group 20. The folding along the second crease 112 makes part of the battery insulation film 10 cover the opposite sides of the through hole 100, and the folding along the first crease 111 makes part of the battery insulation film 10 cover the two sides of the pole group 20 in the first direction D1.

[0062] In the embodiment, as shown in FIGS. 1-3, the creases 110 further include third creases 113 formed as linear structures extending in the first direction D1; the third creases 113 are arranged in the range of the area surrounded by the through hole 100 and the second creases 112 in the second direction D2, i.e. the third creases 113 are located between the through hole 100 and the second creases 112 in the second direction D2, and the third creases 113 are preferably arranged as two, and the two third creases 113 are arranged at the two ends of the through hole 100 in the second direction D2 in the unfolded state of the cell insulation film 10, and the cell insulation film 10 is folded along the first creases 111 and the third creases 113 to cover the surface of the pole group 20 adjacent to the side where the tab portion 21 is arranged. In an optional embodiment, the two third creases 113 are symmetrically arranged with respect to the center line of the cell insulation film 10 extending in the first direction D1.

[0063] According to the cell insulation film provided by the present application, the creases are formed on the cell insulation film, and the cell insulation film is folded along the creases to cover the outer wall of the pole group; the through hole is arranged on the cell insulation film to allow the tab portion on the pole group to pass through; by limiting 110%≤A / A1≤200%, where A is the size of the through hole in the first direction, and A1 is the size of the tab portion in the first direction, the size of the through hole is avoided to be too small to affect the assembly efficiency of the cell insulation film and the pole group, and the size of the through hole is also avoided to be too large to cause the cell insulation film to be unable to completely wrap the pole group, thereby improving the insulation performance and assembly efficiency of the pole group, and further improving the yield and production efficiency of the cell.

[0064] According to the cell provided by the present application, the cell includes the cell insulation film as described above, and the insulation film can completely wrap the pole group, thereby improving the insulation performance and assembly efficiency of the pole group, and further improving the yield and production efficiency of the cell.

[0065] Although the embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and purposes of the present application, and the scope of the present application is defined by the claims and their equivalents. Industrial applicability

[0066] The cell insulation film of the present application, the creases are formed on the cell insulation film, and the cell insulation film is folded along the creases to cover the outer wall of the pole group; the through hole is arranged on the cell insulation film to allow the tab portion on the pole group to pass through; by limiting 110%≤A / A1≤200%, where A is the size of the through hole in the first direction, and A1 is the size of the tab portion in the first direction, the size of the through hole is avoided to be too small to affect the assembly efficiency of the cell insulation film and the pole group, and the size of the through hole is also avoided to be too large to cause the cell insulation film to be unable to completely wrap the pole group, thereby improving the insulation performance and assembly efficiency of the pole group, and further improving the yield and production efficiency of the cell.

Claims

1. An electric chip insulation film, characterized by, A fold is formed on the cell insulation film, and the cell insulation film is folded along the fold to wrap the outer wall of the electrode group; A through hole is formed on the cell insulation film to allow the tab on the electrode group to pass through; The size of the through hole in the first direction is A, in mm; the size of the tab in the first direction is A1, in mm; 110%≤A / A1≤200%; The electrode group comprises at least one electrode group unit, at least part of the electrode group unit is formed by stacking a plurality of electrode sheets, the size of the electrode group unit in the second direction is B3, in mm; the size of the through hole in the second direction is B, in mm; 30%≤B / B3≤100%.

2. The cell insulation film according to claim 1, characterized by, At least part of the electrode group unit is formed by winding the electrode sheet, the tabs on the electrode group unit are connected to form the tab, the size of the tab in the second direction is B1, in mm; the size of the through hole in the second direction is B, in mm; 30%≤B / B1≤200%.

3. The cell insulation film according to claim 2, characterized by, The fold comprises: A first fold, before folding, the first fold is formed as a linear structure extending in the second direction; A second fold, before folding, the second fold is formed as a linear structure extending in the first direction.

4. The cell insulation film according to claim 3, characterized by, The distance between the first fold and the edge of the cell insulation film in the first direction is D; When the electrode group unit is formed by winding the electrode sheet, (0.5×N×B2+3)mm≤D≤(N×B2)mm, B2 is the size of the electrode group unit in the second direction; When the electrode group unit is formed by stacking the electrode sheet, (0.5×N×B3+3)mm≤D≤(N×B3)mm; N is the number of electrode group units.

5. The cell insulation film according to claim 3, characterized by The distance between the second fold and the edge of the cell insulation film in the second direction is C; When the electrode group unit is formed by winding the electrode sheet, (0.5×N×B2+3)mm≤C≤(N×B2)mm, B2 is the size of the electrode group unit in the second direction; When the electrode group unit is formed by stacking the electrode sheet, (0.5×N×B3+3)mm≤C≤(N×B3)mm; N is the number of electrode group units.

6. The cell insulation film according to claim 3, characterized by The end of the first fold in the second direction is provided with an opening.

7. The cell insulation film according to claim 3, characterized by, The fold further comprises: A third fold, formed as a linear structure extending in the first direction; in the second direction, the third fold is arranged within the range of the area surrounded by the through hole and the second fold.

8. The cell insulation film according to claim 1, characterized by, The through hole is provided with a plurality of through holes, and the plurality of through holes are arranged in the first direction.

9. An electric cell characterized by The cell insulation film according to any one of claims 1 to 8.

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