Insulating film, battery cell and battery pack

Abstract

The utility model provides an insulating film, a battery cell and a battery pack, the insulating film comprises a first diaphragm located in the middle, second diaphragms connected to the two sides of the first diaphragm, and third diaphragms connected to the outer sides of the second diaphragms, and the first diaphragm and the second diaphragms are arranged in a staggered mode. Each second diaphragm and the corresponding third diaphragm can be folded in half, two ends of the first diaphragm and two ends of each third diaphragm are respectively provided with short folding edges which can be respectively connected with cover plates at two ends of a battery cell shell in a bonding manner, and two ends of each second diaphragm are respectively provided with long folding edges which can be respectively connected with the cover plates in a bonding manner; the two ends of the long folding edge are respectively provided with a convex edge which protrudes outwards, and each convex edge can be connected with the short folding edge and the cover plate in an adhesive mode at the same time. According to the insulating film provided by the utility model, through the arrangement of the long folding edge, the short folding edge and the convex edge, the connection between the end part of the insulating film and the cover plate can be improved, and through the arrangement of the convex edge on the long folding edge, the long folding edge and the short folding edge can be prevented from warping.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and in particular to an insulating film; at the same time, the utility model also relates to a battery core having the insulating film, and a battery pack provided with the battery core. Background Art

[0002] The insulating film on the battery cell shell is an important part of the battery manufacturing process. The main purpose of the insulating film is to prevent the battery cell from being corroded by foreign substances, such as water vapor, dust, etc. These substances may have a negative impact on the battery cell, such as causing accidents such as battery cell short circuit and fire. At the same time, the insulating film can also effectively prevent the battery cell from being corroded by external substances, thereby protecting the safety and stability of the battery cell.

[0003] The insulating film also has an insulating effect. When a short circuit occurs inside the battery cell, it can effectively prevent foreign substances from entering, thereby reducing the risk of short circuit. During the charging and discharging process, the battery cell generates a lot of heat. When overcharging or short circuit occurs, the insulating film can prevent the battery cell from overheating, thereby reducing the risk of battery cell fire.

[0004] The insulating film in the prior art usually adopts a sheet film, which is wrapped around the outer periphery of the battery cell shell, and both ends extend out of the battery cell shell to be bonded to the cover plate on the battery cell shell. Usually, the extended part of the insulating film is directly folded into a folded edge and bonded to the cover plate, but the end of the folded edge in the bonded state is prone to warping, thereby affecting the connection effect of the insulating film on the cover plate. Therefore, it is particularly important to optimize the structure of the insulating film to prevent the folded edge from warping. Utility Model Content

[0005] In view of this, the utility model aims to provide an insulating film to prevent the insulating film and the cover plate from warping.

[0006] In order to achieve the above object, the technical solution of the utility model is implemented as follows:

[0007] An insulating film, comprising a first film sheet located in the middle, second films sheets connected to both sides of the first film sheet, and a third film sheet connected to the outside of each second film sheet, wherein the first film sheet and each second film sheet, and each second film sheet and the corresponding third film sheet can be folded in half and wrapped around the outer periphery of a battery cell shell, and the two second film sheets are located on both sides of the battery cell shell in the thickness direction;

[0008] Both ends of the first diaphragm and each of the third diaphragms have short folded edges that can be folded and bonded to the cover plates at both ends of the battery cell shell, and both ends of the second diaphragm are respectively provided with long folded edges that can be folded and bonded to the cover plates, and both ends of the long folded edges are respectively provided with convex edges that are protruding outwards, and each of the convex edges can be bonded to the short folded edges and the cover plates at the same time.

[0009] Furthermore, a gap is provided between at least one end of the long folded edge and the adjacent short folded edge.

[0010] Furthermore, the convex edge covers part of the outer surface of the short folded edge and is bonded to the short folded edge; or, the convex edge is bonded to the cover plate, and part of the short folded edge is bonded to the outer surface of the convex edge.

[0011] Furthermore, the two third membrane sheets are at least partially overlapped after being folded in half.

[0012] Furthermore, the shortest distance a between the convex edge and the root of the short folded edge satisfies: 0<a≤15mm.

[0013] Furthermore, the width b of the long folded edge satisfies: b≥2mm.

[0014] Furthermore, the shortest distance c between the convex edge and the output pole block on the cover plate and the shortest distance d between the root of the short folded edge and the output pole block satisfy the following conditions: 0.2mm<c≤d-2mm.

[0015] Furthermore, the first diaphragm is provided with a through hole corresponding to the pressure relief hole on the battery cell housing.

[0016] Compared with the prior art, the utility model has the following advantages:

[0017] The insulating film described in the utility model is connected to the cover plate through the short folded edges at both ends of the first diaphragm and each third diaphragm, and the long folded edges at both ends of the second diaphragm, and is connected to the short folded edges and the cover plate at the same time through the convex edges at both ends of the long folded edges, which is beneficial to prevent the ends of each folded edge from warping, thereby helping to improve the bonding firmness of the insulating film on the cover plate.

[0018] In addition, by providing a notch, the folding effect of the short fold and the long fold is facilitated, thereby improving the connection effect between the two and the cover plate. The convex edge covers part of the outer surface of the short fold and is bonded to the short fold, which is conducive to preventing the short fold from warping; the short fold is bonded to the outer surface of the convex edge, which is also conducive to preventing the fold from warping. The setting of the relationship between the shortest distance c between the convex edge and the output pole block on the cover plate and the shortest distance d between the root of the short fold and the output pole block is conducive to preventing the fold from warping while meeting the connection requirements. The through hole is provided on the first diaphragm, which is conducive to the pressure relief effect of the pressure relief hole on the battery cell shell, thereby improving the safety of the battery cell.

[0019] In addition, another object of the present invention is to provide a battery cell, comprising a battery cell shell and the insulating film as described above, wherein the insulating film is coated on the battery cell shell.

[0020] The battery cell of the utility model is provided with the above insulating film, which is beneficial to improving the connection effect of the insulating film, thereby improving the safety of the battery cell.

[0021] In addition, the utility model also provides a battery pack, including the above-mentioned battery cell.

[0022] The battery pack described in the present invention has the same beneficial effects as the above-mentioned battery cell, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the accompanying drawings:

[0024] Figure 1 It is a schematic structural diagram of the insulating film in an expanded state according to an embodiment of the utility model;

[0025] Figure 2 It is a schematic structural diagram of the insulating film and the battery cell according to an embodiment of the utility model at one viewing angle;

[0026] Figure 3 It is a schematic structural diagram of the insulating film and the battery cell described in an embodiment of the utility model from another perspective.

[0027] Description of reference numerals:

[0028] 1. First diaphragm; 2. Second diaphragm; 3. Third diaphragm; 4. Cover plate;

[0029] 101, short folded edge; 102, through hole;

[0030] 201, long folded edge; 202, convex edge;

[0031] 401, output pole block;

[0032] A, first fold line; B, second fold line; C, third fold line; D, fourth fold line. DETAILED DESCRIPTION

[0033] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0034] In the description of the present invention, it should be noted that if there are terms indicating orientation or positional relationship such as "upper", "lower", "inner", "back", etc., they are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, if there are terms such as "first", "second", etc., they are also used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0035] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0036] This embodiment relates to an insulating film, the structure of which in an unfolded state is as follows: Figure 1 As shown in the figure, the structure connected to the battery cell is as follows Figure 2 and Figure 3 As shown in . The insulating film includes a first diaphragm 1 located in the middle, second diaphragms 2 connected to both sides of the first diaphragm 1, and third diaphragms 3 connected to the outside of each second diaphragm 2. The first diaphragm 1 and each second diaphragm 2, and each second diaphragm 2 and the corresponding third diaphragm 3 can be folded in half and wrapped around the outer periphery of the battery shell, and the two second diaphragms 2 are located on both sides of the battery shell in the thickness direction.

[0037] Among them, the first diaphragm 1 and each third diaphragm 3 have short folded edges 101 at both ends that can be folded and bonded to the cover plates 4 at both ends of the battery cell shell, and the second diaphragm 2 has long folded edges 201 at both ends that can be folded and bonded to the cover plates 4, and the two ends of the long folded edges 201 are respectively provided with convex edges 202 that are protruding outward, and each convex edge 202 can be bonded to the short folded edge 101 and the cover plate 4 at the same time.

[0038] The insulating film described in this embodiment is connected to the cover plate 4 through the short folded edges 101 at both ends of the first diaphragm 1 and each third diaphragm 3, and the long folded edges 201 at both ends of the second diaphragm, and is connected to the short folded edges 101 and the cover plate 4 at the same time through the convex edges 202 at both ends of the long folded edges 201, which helps to prevent the ends of each folded edge from warping, thereby helping to improve the bonding firmness of the insulating film on the cover plate 4.

[0039] Based on the above overall introduction, Figure 1 As shown in the figure, the insulating film in the unfolded state is rectangular as a whole, the first film sheet 1 and the two adjacent second film sheets 2 are folded along the first fold line A, and the second film sheet 2 and the adjacent third film sheet 3 are folded along the second fold line B, so that the folded insulating film is rectangular as a whole to match the shape of the battery cell. Among them, the two second film sheets 2 are arranged opposite to each other in the thickness direction of the battery cell, the two third film sheets 3 are located on one side of the width direction of the battery cell shell, and the first film sheet 1 is located on the other side of the width direction of the battery cell shell.

[0040] As a preferred embodiment, the two third diaphragms 3 are at least partially overlapped after being folded in half. Specifically, the sum of the widths of the two third diaphragms 3 is greater than the thickness of the battery cell shell. The third diaphragm 3 located on the inner side is bonded to the side of the battery cell shell, and the third diaphragm 3 located on the outer side is partially bonded to the side of the battery cell shell, and the other part is bonded to the outer side of the inner third diaphragm 3. This is conducive to improving the connection strength between the connection of the two third diaphragms 3 and the battery cell shell, thereby preventing the third diaphragm 3 from warping, and is easy to arrange and implement.

[0041] To facilitate the connection between the two ends of the insulating film and the cover plate 4, as Figure 1 As shown in , each short fold 101 is folded along the third fold line C, each long fold 201 is folded along the fourth fold line D, and the long fold 201 and the short fold 101 are both bonded to the cover plate 4. The short folds 101 on the two third membrane sheets 3 are also partially overlapped and bonded to the cover plate 4. It can be understood that the third fold line C and the fourth fold line D in this embodiment are collinear.

[0042] As a preferred connection method, Figure 2 As shown in , the convex edge 202 covers part of the outer surface of the short folded edge 101 and is bonded to the short folded edge 101. That is, the short folded edge 101 is first bonded to the cover plate 4, and the long folded edge 201 is then bonded to the cover plate 4. At this time, part of the convex edge 202 covers the outer surface of the end of the short folded edge 101 and is bonded to the short folded edge 101, and the other part of the convex edge 202 covers the cover plate 4 and is bonded to the cover plate 4. Of course, the convex edge 202 can also be bonded to the cover plate 4, and part of the short folded edge 101 can be bonded to the outer surface of the convex edge 202, which can also help prevent the folded edge from warping.

[0043] In this embodiment, by providing convex edges 202 at both ends of the long folded edge 201, on the one hand, it is helpful to increase the connection strength between the two ends of the long folded edge 201 and the cover plate 4, so that the two ends of the long folded edge 201 are not easy to warp, and on the other hand, the convex edge 202 is covered with the short folded edge 101 and is also bonded to the cover plate 4, which is helpful to prevent the end of the short folded edge 101 from warping. In addition, the structure of the convex is simple, easy to process and form, and easy to connect.

[0044] As a feasible implementation, in this embodiment, a notch is provided between at least one end of the long folded edge 201 and the adjacent short folded edge 101. The notch is also cut by a cutter, which facilitates the separation of the short folded edge 101 and the long folded edge 201 and their bonding connection with the cover plate 4. Preferably, a notch is provided between each end of the long folded edge 201 and the adjacent short folded edge 101, which further helps to prevent the occurrence of the warping problem.

[0045] As shown in the figure, in this embodiment, the shortest distance a between the convex edge 202 and the root of the short folded edge 101 satisfies: 0<a≤15mm. For example, the shortest distance a here can be 1mm, 3mm, 6mm, 9mm, 12mm or 15mm, etc. This is conducive to improving the connection effect between the convex edge 202 and the short folded edge 101, and has a good anti-warping effect. When the shortest distance a is greater than 15mm, the connection area between the convex edge 202 and the short folded edge 101 will be reduced, and the improvement effect on the anti-warping problem is not obvious.

[0046] In addition, if Figure 2 As shown in , in this embodiment, the width b of the long fold 201 satisfies: b ≥ 2 mm. This helps to ensure the connection strength between the long fold 201 and the cover plate 4. In specific implementation, for example, the width b of the long fold 201 can be 2 mm, 2.5 mm, 3 mm or 4 mm. In this embodiment, the width of the short fold 101 is preferably larger than the width of the long fold 201, as long as the bonding effect of the short fold 101 on the cover plate 4 is satisfied.

[0047] After multiple verifications, in this embodiment, still refer to Figure 2 As shown in , the shortest distance c between the flange 202 and the output pole block 401 on the cover plate 4, and the shortest distance d between the root of the short folded edge 101 and the output pole block 401 satisfy: 0.2mm<c≤d-2mm. Such a setting is conducive to further ensuring the connection and anti-warping effect of the flange 202. In specific implementation, when the shortest distance c is less than 2mm, the coverage area of ​​the flange 202 is large, which is easy to cause excess function, thereby causing waste. When the shortest distance is greater than d-2mm, it will affect the connection area and strength between the flange 202 and the cover plate 4, which is not conducive to solving the anti-warping problem.

[0048] To improve the versatility of the insulating film and meet the layout requirements on different battery cell shells. Figure 1 As shown in the figure, the first diaphragm 1 is provided with a through hole 102 corresponding to the pressure relief hole on the battery cell housing. Providing the through hole 102 on the first diaphragm 1 is beneficial to the pressure relief effect of the pressure relief hole on the battery cell housing, thereby improving the safety of the battery cell. Of course, in a specific implementation, if the side of the battery cell housing is not provided with a pressure relief hole, there is no need to provide the through hole 102 structure.

[0049] It is understandable that in this embodiment, a matching hole structure can be selectively provided on each diaphragm according to whether other structures are arranged on the side of the battery cell shell to ensure the use effect of the battery cell.

[0050] The insulating film in this embodiment can effectively prevent the ends of the long folded edge 201 and the short folded edge 101 from warping by optimizing the folded edges at the ends of each diaphragm and the connection relationship between the folded edges, especially the setting of the convex edge 202 on the long folded edge 201, thereby helping to improve the insulating protection effect of the insulating film on the battery cell.

[0051] In addition, the present embodiment also relates to a battery cell, including a battery cell shell and the insulating film as described above, wherein the insulating film is coated on the battery cell shell.

[0052] The battery cell described in this embodiment is provided with the above insulating film, which is beneficial to improving the connection effect of the insulating film, thereby improving the safety of the battery cell.

[0053] In addition, this embodiment also provides a battery pack, including the above-mentioned battery cell. The battery pack has the same beneficial effects as the above-mentioned battery cell, which will not be described in detail here.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An insulating film, characterized in that: It includes a first diaphragm located in the middle, second diaphragms connected to both sides of the first diaphragm, and a third diaphragm connected to the outside of each second diaphragm, the first diaphragm and each second diaphragm, and each second diaphragm and the corresponding third diaphragm can be folded in half and wrapped around the outer periphery of the battery shell, and the two second diaphragms are located on both sides of the battery shell in the thickness direction; Both ends of the first diaphragm and each of the third diaphragms have short folded edges that can be folded and bonded to the cover plates at both ends of the battery cell shell, and both ends of the second diaphragm are respectively provided with long folded edges that can be folded and bonded to the cover plates, and both ends of the long folded edges are respectively provided with convex edges that are protruding outwards, and each of the convex edges can be bonded to the short folded edges and the cover plates at the same time.

2. The insulating film according to claim 1, wherein: A gap is provided between at least one end of the long folded edge and the adjacent short folded edge.

3. The insulating film according to claim 1, wherein: The convex edge covers part of the outer surface of the short folded edge and is bonded to the short folded edge; or, The convex edge is bonded to the cover plate, and part of the short folded edge is bonded to the outer surface of the convex edge.

4. The insulating film according to claim 1, wherein: The two third membrane sheets are at least partially overlapped after being folded in half.

5. The insulating film according to claim 1, wherein: The shortest distance a between the convex edge and the root of the short folded edge satisfies: 0<a≤15mm.

6. The insulating film according to claim 1, wherein: The width b of the long folded edge satisfies: b≥2mm.

7. The insulating film according to claim 1, characterized in that: The shortest distance c between the convex edge and the output pole block on the cover plate and the shortest distance d between the root of the short folded edge and the output pole block satisfy the following conditions: 0.2 mm < c ≤ d-2 mm.

8. The insulating film according to claim 1, wherein: The first diaphragm is provided with a through hole corresponding to the pressure relief hole on the battery cell housing.

9. A battery cell, characterized in that: The invention comprises a battery cell case and the insulating film according to any one of claims 1 to 8, wherein the insulating film is coated on the battery cell case.

10. A battery pack, characterized in that: Comprising the battery cell as claimed in claim 9.

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