A type of battery cell
By using an asymmetric coating of insulating film, the problem of space waste when stacking square cells is solved, achieving efficient and compact arrangement of battery modules and high volumetric energy density.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SUZHOU QINGTAO NEW ENERGY TECH CO LTD
- Filing Date
- 2025-07-29
- Publication Date
- 2026-07-17
AI Technical Summary
The existing method of fully covering the insulating film of square battery cells results in wasted space when battery modules are stacked, which affects the volumetric energy density.
By adopting an asymmetric wrapping method of insulating film, some sides of the battery cell body are not covered with insulating film. When stacked, only one layer of film is retained. The film is bent to provide insulation wrapping at the battery cell connection, reducing the number of film layers and saving space.
This improves the volumetric energy density of the battery module, avoids wasted space, and ensures the safety and stability of the battery cells.
Smart Images
Figure CN224520141U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of power battery technology, and in particular to a battery cell. Background Technology
[0002] In the field of new energy vehicles, power batteries have become the main energy source for new energy vehicles, among which square aluminum-cased power batteries are widely used. Since the outer surface of the square cells of square aluminum-cased power batteries usually has electrodes, the outer surface of the square cells needs to be insulated to ensure the safety of the square cells in use.
[0003] Currently, the insulation protection for prismatic battery cells is typically achieved by fully covering them with insulating film. This means that the bottom surface, two opposite first sides, and two opposite second sides of the prismatic cell are completely covered with insulating film. When prismatic cells formed using this method are subsequently stacked into battery modules, at least two layers of insulating film are required between adjacent prismatic cells. As the number of prismatic cells increases, multiple layers of insulating film accumulate in the stacking direction, resulting in wasted space and affecting the volumetric energy density of the battery module.
[0004] To address the above issues, a new type of battery cell is urgently needed. Utility Model Content
[0005] The purpose of this invention is to propose a battery cell that can ensure the insulation safety between individual battery cells and improve the volumetric energy density of the battery module.
[0006] To achieve this objective, the present invention adopts the following technical solution:
[0007] Battery cells, including:
[0008] The battery cell body has a bottom surface, two opposing first side surfaces, and two opposing second side surfaces, wherein the first side surfaces, the second side surfaces, and the bottom surface are perpendicular to each other.
[0009] An insulating film includes a first film, a second film, and a third film. The first film covers one of the first side surfaces, the second film covers one of the second side surfaces, and the third film covers the bottom surface. The first side of the cell body not covered by the first film is positioned toward the adjacent first side of the cell body covered by the first film, and the second side of the cell body not covered by the second film is positioned toward the adjacent second side of the cell body covered by the second film.
[0010] As an optional solution, the insulating film is an integral structure, with a first crease line formed between the first film and the second film, and a second crease line formed between the first film and the third film.
[0011] As an optional solution, a first curved surface is formed at the connection between adjacent first side and second side, a first bent film is connected to the side of the first film away from the second film, the first bent film covers the first curved surface between the adjacent first side covered by the first film and the second side not covered by the second film, and along the length direction of the cell body, the outer edge of the first bent film does not extend beyond the second side not covered by the second film.
[0012] As an alternative, a second bent film is connected to the side of the second film away from the first film. The second bent film covers the first curved surface between the adjacent first side that is not covered by the first film and the second side that is covered by the second film. Along the width direction of the cell body, the outer edge of the second bent film does not extend beyond the first side that is not covered by the first film.
[0013] As an optional solution, a second curved surface is formed at the connection between the first side surface and the bottom surface, and a third bent film is connected to the side of the third film away from the first film. The third bent film covers the second curved surface, and along the width direction of the cell body, the outer edge of the third bent film does not extend beyond the first side surface that is not covered by the first film.
[0014] As an optional solution, a third curved surface is formed at the connection between the adjacent second side surface and the bottom surface, and a fourth bent film is connected to one side of the third film. The fourth bent film is disposed adjacent to the third bent film, and the fourth bent film covers the third curved surface. Along the length direction of the cell body, the outer edge of the fourth bent film does not extend beyond the second side surface that is not covered by the second film.
[0015] As an optional solution, a first notch is provided between the first bent film and the fourth bent film, and between the third bent film and the fourth bent film.
[0016] As an optional feature, the insulating film further includes:
[0017] A first overlapping film is connected to one side of the third film. The first overlapping film is used to bend and cover the second side and is bonded to the second film. A fifth bending film is connected to the side of the first overlapping film away from the second film. The fifth bending film is used to cover part of the first bending surface, and a second notch is provided between the third bending film and the fifth bending film.
[0018] As an optional feature, the insulating film further includes:
[0019] A second overlapping film is connected to one side of the second film. The second overlapping film is used to bend and cover the bottom surface and is bonded to the third film. A sixth bending film is connected to the side of the second overlapping film away from the third film. The sixth bending film is used to cover part of the second bending surface, and a third notch is provided between the sixth bending film and the second bending film.
[0020] As an optional feature, the insulating film further includes:
[0021] A third overlapping film, wherein adjacent sides of the third overlapping film are respectively connected to the second film and the third film, and a first folding slit is cut on the second film or the third overlapping film; or
[0022] The third membrane or the third overlapping membrane has a second fold cut.
[0023] The beneficial effects of this utility model are as follows:
[0024] By having a bottom surface, two opposing first sides, and two opposing second sides, with each of the first and second sides and the bottom surface perpendicular to the others, and by covering one of the first sides, the second side, and the bottom surface with an insulating film, and leaving the other two sides of the cell body uncovered, the cells are stacked into a battery module. The uncovered first side faces the adjacent cell with its first film covering it, and the uncovered second side faces the adjacent cell with its second film covering it. This arrangement ensures that there is only one layer of film between adjacent cells. This reduces the number of film layers between adjacent cells in the arrangement direction, avoiding the waste of space by multiple layers of film, resulting in a more compact cell arrangement and ultimately improving the volumetric energy density of the battery module. Attached Figure Description
[0025] Figure 1 This is a schematic diagram of the battery cell structure provided in Embodiment 1 of this utility model;
[0026] Figure 2 This is a schematic diagram of the flattened structure of the insulating film provided in Embodiment 1 of this utility model;
[0027] Figure 3 This is a schematic diagram of the battery cell structure provided in Embodiment 2 of this utility model;
[0028] Figure 4 This is a schematic diagram of the flattened structure of the insulating film provided in Embodiment 2 of this utility model;
[0029] Figure 5 This is a schematic diagram of the flattened structure of the insulating film (with a first folding slit on the second film) provided in Embodiment 3 of this utility model;
[0030] Figure 6 This is a schematic diagram of the flattened structure of the insulating film (with a first folded slit on the third overlapping film) provided in Embodiment 3 of this utility model;
[0031] Figure 7 This is a schematic diagram of the flattened structure of the insulating film (with a second folding slit on the third film) provided in Embodiment 3 of this utility model;
[0032] Figure 8 This is a schematic diagram of the flattened structure of the insulating film (with a second folding slit on the third overlapping film) provided in Embodiment 3 of this utility model.
[0033] Explanation of reference numerals in the attached figures:
[0034] 1-Cell body; 11-First side; 12-Second side;
[0035] 2-Insulating film; 21-First film; 22-Second film; 23-Third film; 241-First overlapping film; 242-Second overlapping film; 243-Third overlapping film; 25-First crease line; 26-Second crease line; 271-First bent film; 272-Second bent film; 273-Third bent film; 274-Fourth bent film; 275-Fifth bent film; 276-Sixth bent film; 281-First notch; 282-Second notch; 283-Third notch; 291-First fold cut; 292-Second fold cut. Detailed Implementation
[0036] All features disclosed in this specification, or steps in all methods or processes disclosed herein, may be combined in any way, except for mutually exclusive features and / or steps.
[0037] Any feature disclosed in this specification, unless specifically stated otherwise, may be replaced by other equivalent or similar features. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features. Throughout this specification, the same reference numerals indicate the same elements.
[0038] To make the technical problem solved by this utility model, the technical solution adopted, and the technical effect achieved clearer, the technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments.
[0039] Since the outer surface of a battery cell typically has electrodes, it needs to be insulated to ensure its safety. Currently, the insulation protection for battery cells is usually achieved by fully covering them with an insulating film, meaning that the bottom surface, two opposite first sides, and two opposite second sides of the square battery cell are completely covered with an insulating film. When square battery cells formed using this method are subsequently stacked into a battery module, at least two layers of insulating film are present between adjacent square cells. As the number of square cells increases, multiple layers of insulating film accumulate in the stacking direction, resulting in wasted space and affecting the volumetric energy density of the battery module.
[0040] Example 1
[0041] Therefore, this embodiment proposes a battery cell for stacking and arranging into a battery module. This battery cell occupies a small space, ensuring a compact arrangement of the cells in the arrangement direction when stacking them into a battery module, avoiding wasted space and thus improving the volumetric energy density of the stacked battery module; moreover, the cost of this battery cell is low. Specifically, the battery cell involved in this embodiment can be a square aluminum-cased battery cell, and correspondingly, the battery module can be a square aluminum-cased battery module. Here, the specific types of battery cells and battery modules are not limited.
[0042] It is worth noting that the main improvement in this embodiment lies in the improvement of the space used for stacking and arranging the individual cells. Here, the specific structure of the cells, the working principle of the cells and the battery module will not be described in detail. Please refer to the existing structure and working principle of cells and battery modules.
[0043] Specifically, such as Figure 1 and Figure 2 As shown, the battery cell includes a battery cell body 1 and an insulating film 2; wherein, the battery cell body 1 has a bottom surface, two opposing first side surfaces 11 and two opposing second side surfaces 12, and the first side surfaces 11, the second side surfaces 12 and the bottom surface are perpendicular to each other; the insulating film 2 includes a first film 21, a second film 22 and a third film 23, the first film 21 covers one of the first side surfaces 11, the second film 22 covers one of the second side surfaces 12, and the third film 23 covers the bottom surface; and the first side surface 11 of the battery cell body 1 not covered by the first film 21 is used to face the adjacent first side surface 11 of the battery cell body 1 covered by the first film 21, and the second side surface 12 of the battery cell body 1 not covered by the second film 22 is used to face the adjacent second side surface 12 of the battery cell body 1 covered by the second film 22.
[0044] Compared with the prior art, the battery cell in this embodiment changes the specific arrangement of the insulating film 2 and the specific wrapping arrangement of the insulating film 2 on the battery cell body 1. By making the first film 21 of the insulating film 2 cover one of the first side 11, the second film 22 cover one of the second side 12, and the third film 23 cover the bottom surface, that is, the other first side 11 and the other second side 12 of the battery cell body 1 are not covered with the insulating film 2. In the subsequent process of stacking and arranging the individual battery cells into a battery module, the first side 11 of the battery cell body 1 that is not covered with the first film 21 is placed towards the first side 11 of the adjacent battery cell body 1 that is covered with the first film 21, and the second side 12 of the battery cell body 1 that is not covered with the second film 22 is placed towards the second side 12 of the adjacent battery cell body 1 that is covered with the second film 22, so that there is only one layer of film between two adjacent battery cells. This configuration reduces the number of film layers between adjacent cells in the arrangement direction, avoiding the waste of space by multiple layers of film occupying too much space and making the cell arrangement more compact, thereby improving the volumetric energy density of the battery module.
[0045] It is worth noting that the dashed lines in the accompanying drawings of this embodiment are fold lines, which can all be folded, and the solid lines in the accompanying drawings are cut-off lines; furthermore, the structure in the accompanying drawings of this embodiment cannot explain the entire folding and covering sequence of the insulating film 2. The specific folding and covering sequence of the insulating film 2 can be determined according to the actual covering requirements and the specific structure of the insulating film 2.
[0046] It is worth noting that the aforementioned battery cell body 1 specifically includes a battery cell body and an outer shell body. The battery cell body is disposed inside the outer shell body, and the insulating film 2 in this embodiment is specifically covered on each surface of the outer shell body.
[0047] Furthermore, such as Figure 2 As shown, the insulating film 2 is an integral structure, that is, it is a single connected structure. This ensures the stability and integrity of the covering of the battery cell body 1 by the first film 21, the second film 22, and the third film 23 when covering the outer surface of the battery cell body 1. Specifically, it ensures the stability and integrity of the covering at the connection between the first side 11 and the second side 12, and at the connection between the first side 11 and the bottom surface. Furthermore, the insulating film 2 is specifically an integrally folded structure, meaning it is an integral structure that can be folded and unfolded.
[0048] Specifically, such as Figure 1 and Figure 2As shown, a first fold line 25 is formed between the first film 21 and the second film 22, so that the second film 22 can be bent to cover the second side 12 after the first film 21 is covered by the first side 11; and a second fold line 26 is formed between the first film 21 and the third film 23, so that the third film 23 can be bent to cover the bottom surface after the first film 21 is covered by the first side 11; thereby ensuring the fit of the insulating film 2 to adjacent surfaces and the joints between adjacent surfaces, and ensuring that there is no problem of adhesion interference between the first film 21, the second film 22 and the third film 23 during the covering process.
[0049] Furthermore, such as Figure 1 and Figure 2 As shown, a first curved surface is formed at the connection between adjacent first side 11 and second side 12. A first bent film 271 is connected to the side of the first film 21 away from the second film 22. The first bent film 271 matches the first curved surface. The first bent film 271 covers the first curved surface between the adjacent first side 11 covered with the first film 21 and the second side 12 not covered with the second film 22, so as to ensure the insulating covering effect of the first curved surface.
[0050] Specifically, along the length of the cell body 1, the outer edge of the first bent film 271 does not extend beyond the second side 12 not covered by the second film 22. The length direction of the cell body 1 is specifically as follows: Figure 1 As shown by arrow A in the diagram. This arrangement ensures insulation of the first curved surface while reducing the space occupied by the first bending film 271 along the length of the cell body 1, thereby improving the volumetric energy density of the battery module.
[0051] Furthermore, such as Figure 1 and Figure 2 As shown, a second bent membrane 272 is connected to the side of the second membrane 22 away from the first membrane 21. The second bent membrane 272 matches the first curved surface. The second bent membrane 272 covers the first curved surface between the adjacent first side 11 that is not covered by the first membrane 21 and the second side 12 covered by the second membrane 22, so as to ensure the insulation covering effect of the first curved surface.
[0052] Specifically, along the width direction of the cell body 1, the outer edge of the second bent film 272 does not extend beyond the first side surface 11 not covered by the first film 21. The width direction of the cell body 1 is specifically as follows: Figure 1 As shown by arrow B in the diagram. This configuration ensures insulation of the first curved surface while reducing the space occupied by the second bending film 272 in the width direction of the cell body 1, thereby further improving the volumetric energy density of the battery module.
[0053] Furthermore, such as Figure 1 and Figure 2 As shown, a second curved surface is formed at the connection between the first side surface 11 and the bottom surface. A third bent film 273 is connected to the side of the third film 23 away from the first film 21. The third bent film 273 matches the second curved surface. The third bent film 273 covers the second curved surface between the adjacent bottom surface covered with the third film 23 and the first side surface 11 not covered with the first film 21, so as to ensure the insulating covering effect of the second curved surface.
[0054] Specifically, along the width direction of the cell body 1, the outer edge of the third bending film 273 does not extend beyond the first side 11 that is not covered by the first film 21, so as to reduce the space occupied by the third bending film 273 in the width direction of the cell body 1 while ensuring the insulation effect of the second bending surface, so as to better improve the volumetric energy density of the battery module.
[0055] Furthermore, such as Figure 1 and Figure 2 As shown, a third curved surface is formed at the connection between the adjacent second side surface 12 and the bottom surface. A fourth bent film 274 is connected to one side of the third film 23. The fourth bent film 274 is disposed adjacent to the third bent film 273. The fourth bent film 274 matches the third curved surface. The fourth bent film 274 covers the third curved surface between the adjacent bottom surface covered with the third film 23 and the second side surface 12 not covered with the second film 22, so as to ensure the insulating covering effect of the third curved surface.
[0056] Specifically, along the length of the cell body 1, the outer edge of the fourth bending film 274 does not extend beyond the second side 12 that is not covered by the second film 22, so as to reduce the space occupied by the fourth bending film 274 in the length of the cell body 1 while ensuring the insulation effect of the third bending surface, so as to further improve the volumetric energy density of the battery module.
[0057] Furthermore, such as Figure 1 and Figure 2As shown, a first notch 281 is provided between the first bent film 271 and the fourth bent film 274, and between the third bent film 273 and the fourth bent film 274. The first notch 281 prevents multiple layers of film from bonding together and forming a multilayer film structure when adjacent bent films cover the corners of the battery cell body 1. This prevents cracking of the films covering the corners of the battery cell body 1, ensuring a more secure and comfortable covering effect at each corner. Furthermore, it reduces the overlapping area between two adjacent bent films, thus reducing the amount of material used in the insulating film 2. The specific shape and size of the first notch 281 are not limited here, as long as it ensures a more secure and comfortable covering effect at each corner of the battery cell body 1 by adjacent bent films.
[0058] Specifically, such as Figure 1 and Figure 2 As shown, the insulating film 2 also includes a first overlapping film 241. One side of the first overlapping film 241 is connected to the side of the third film 23 that does not have the fourth bending film 274. The first overlapping film 241 is used to bend and cover the second side 12 and adhere to the second film 22. That is, the first overlapping film 241 is bent relative to the third film 23 to cover the second side 12, and then the second film 22 is bent along the first crease line 25 until it is adhered to the first overlapping film 241.
[0059] By setting the first overlapping film 241 so that the first overlapping film 241 and the second film 22 cooperate with each other to cover the second side 12 and the third curved surface between the adjacent second side 12 and the bottom surface, the covering strength and integrity of the second side 12 and the third curved surface can be increased, thereby achieving better insulation covering of the battery cell.
[0060] Furthermore, such as Figure 2 As shown, a fifth bent film 275 is connected to the side of the first overlapping film 241 away from the second film 22. The fifth bent film 275 is used to cover part of the first bent surface so as to better ensure the insulation coverage effect of the first bent surface.
[0061] Specifically, such as Figure 2 As shown, a second notch 282 is provided between the third bending film 273 and the fifth bending film 275 to better prevent the film covering the corners of the battery cell body 1 from cracking, thereby ensuring a more secure and comfortable covering effect at each corner of the battery cell body 1. The specific shape and size of the second notch 282 are not limited here, as long as it ensures a secure and comfortable covering effect at each corner of the battery cell body 1 through the adjacent two bending films. The bending and covering design described above can all be achieved by folding along the corresponding crease lines.
[0062] Example 2
[0063] This embodiment proposes a battery cell, such as... Figure 3 and Figure 4 As shown, the structure of this battery cell is basically the same as that of the battery cell in Embodiment 1. The difference is that the insulating film 2 in this embodiment does not include the first overlapping film 241, but includes the second overlapping film 242.
[0064] Specifically, such as Figure 3 and Figure 4 As shown, one side of the second overlapping film 242 is connected to one side of the second film 22. The second overlapping film 242 is bent to cover the bottom surface and is bonded to the third film 23. That is, the second overlapping film 242 is bent relative to the second film 22 to cover the bottom surface, and then the third film 23 is bent along the second crease line 26 until it is bonded to the second overlapping film 242.
[0065] By setting a second overlapping film 242, the second overlapping film 242 and the third film 23 cooperate with each other to cover the bottom surface and the third curved surface between the adjacent second side surface 12 and the bottom surface, thereby increasing the covering strength and integrity of the bottom surface and the third curved surface, and thus better achieving the insulation covering of the battery cell.
[0066] Furthermore, such as Figure 3 and Figure 4 As shown, a sixth folded membrane 276 is connected to the side of the second overlapping membrane 242 away from the third membrane 23. The sixth folded membrane 276 is used to cover part of the second curved surface to better ensure the insulation coverage effect of the second curved surface.
[0067] Specifically, such as Figure 3 and Figure 4 As shown, a third notch 283 is provided between the sixth bending film 276 and the second bending film 272 to better prevent the film covering the corners of the battery cell body 1 from cracking, and to further ensure a more secure and comfortable covering effect at each corner of the battery cell body 1. Here, the specific shape and size of the third notch 283 are not limited, as long as it ensures a more secure and comfortable covering effect at each corner of the battery cell body 1 through the adjacent two bending films.
[0068] Example 3
[0069] This embodiment proposes a battery cell, such as... Figures 5 to 8 As shown, the structure of this battery cell is basically the same as that of the battery cell in Embodiment 1. The difference is that the insulating film 2 in this embodiment does not include the first overlapping film 241, but includes the third overlapping film 243.
[0070] Specifically, such as Figures 5 to 8As shown, the adjacent sides of the third overlapping membrane 243 are respectively connected to the second membrane 22 and the third membrane 23. A first folding slit 291 is cut on the second membrane 22 or the third overlapping membrane 243; or, a second folding slit 292 is cut on the third membrane 23 or the third overlapping membrane 243, so that the second membrane 22, the third membrane 23 and the third overlapping membrane 243 can be smoothly bent to each other through the first folding slit 291 or the second folding slit 292.
[0071] Specifically, such as Figure 5 As shown, a first folding notch 291 is cut on the second membrane 22, causing the third overlapping membrane 243 to fold along the first folding notch 291 and cover the second side 12. Then, the second membrane 22 is bent to bond it to the third overlapping membrane 243, thereby achieving insulating coverage of the second side 12. In other embodiments, such as... Figure 6 As shown, a first folding notch 291 can also be cut on the third overlapping film 243, so that the second film 22 is folded along the first folding notch 291 to cover the second side 12, and then the third overlapping film 243 is bent to bond with the second film 22, thereby achieving insulation coverage of the second side 12.
[0072] In another embodiment, such as Figure 7 and Figure 8 As shown, a second folding notch 292 can also be cut on the third membrane 23 or the third overlapping membrane 243 to ensure that the second membrane 22, the third membrane 23 and the third overlapping membrane 243 can be smoothly folded and covered by each other through the second folding notch 292.
[0073] Specifically, such as Figure 7 As shown, a second folding notch 292 is cut on the third membrane 23, causing the third overlapping membrane 243 to fold along the second folding notch 292 and cover the bottom surface. Then, the third membrane 23 is bent to bond with the third overlapping membrane 243, thereby achieving insulation coverage of the bottom surface. In other embodiments, such as... Figure 8 As shown, a second folding notch 292 can also be cut on the third overlapping film 243, so that the third film 23 is folded along the second folding notch 292 to cover the bottom surface, and then the third overlapping film 243 is bent to bond with the third film 23, thereby achieving insulation coverage of the bottom surface.
[0074] The above description is only a preferred embodiment of this utility model. For those skilled in the art, there will be changes in the specific implementation method and application scope based on the idea of this utility model. The content of this specification should not be construed as a limitation of this utility model.
Claims
1. An electric cell, characterized by, include: The battery cell body (1) has a bottom surface, two oppositely arranged first side surfaces (11) and two oppositely arranged second side surfaces (12), wherein the first side surfaces (11), the second side surfaces (12) and the bottom surface are perpendicular to each other. The insulating film (2) includes a first film (21), a second film (22) and a third film (23). The first film (21) covers one of the first side surfaces (11), the second film (22) covers one of the second side surfaces (12), and the third film (23) covers the bottom surface. The first side surface (11) of the cell body (1) not covered by the first film (21) is placed toward the first side surface (11) of the adjacent cell body (1) covered by the first film (21), and the second side surface (12) of the cell body (1) not covered by the second film (22) is placed toward the second side surface (12) of the adjacent cell body (1) covered by the second film (22).
2. The cell of claim 1, wherein, The insulating film (2) is an integral structure, with a first crease line (25) formed between the first film (21) and the second film (22), and a second crease line (26) formed between the first film (21) and the third film (23).
3. The cell of claim 1, wherein, A first curved surface is formed at the connection between adjacent first side (11) and second side (12). A first bent film (271) is connected to the side of the first film (21) away from the second film (22). The first bent film (271) covers the first curved surface between the adjacent first side (11) covered by the first film (21) and the second side (12) not covered by the second film (22). Along the length direction of the cell body (1), the outer edge of the first bent film (271) does not extend beyond the second side (12) not covered by the second film (22).
4. The cell of claim 3, wherein, The second membrane (22) is connected to a second bent membrane (272) on the side away from the first membrane (21). The second bent membrane (272) covers the first curved surface between the adjacent first side (11) that is not covered by the first membrane (21) and the second side (12) that is covered by the second membrane (22). Along the width direction of the cell body (1), the outer edge of the second bent membrane (272) does not extend beyond the first side (11) that is not covered by the first membrane (21).
5. The cell of claim 4, wherein, A second curved surface is formed at the connection between the first side surface (11) and the bottom surface. A third bent film (273) is connected to the side of the third film (23) away from the first film (21). The third bent film (273) covers the second curved surface, and along the width direction of the cell body (1), the outer edge of the third bent film (273) does not extend beyond the first side surface (11) that does not cover the first film (21).
6. The cell of claim 5, wherein, A third curved surface is formed at the connection between the adjacent second side surface (12) and the bottom surface. A fourth bent film (274) is connected to one side of the third film (23). The fourth bent film (274) is disposed adjacent to the third bent film (273). The fourth bent film (274) covers the third curved surface, and along the length direction of the cell body (1), the outer edge of the fourth bent film (274) does not extend beyond the second side surface (12) that does not cover the second film (22).
7. The cell of claim 6, wherein, A first notch (281) is provided between the first bent film (271) and the fourth bent film (274), and between the third bent film (273) and the fourth bent film (274).
8. The cell of any one of claims 5-7, wherein, The insulating film (2) also includes: A first overlapping film (241) is connected to one side of the third film (23). The first overlapping film (241) is used to bend and cover the second side (12) and is bonded to the second film (22). A fifth bending film (275) is connected to the side of the first overlapping film (241) away from the second film (22). The fifth bending film (275) is used to cover part of the first bending surface. A second notch (282) is provided between the third bending film (273) and the fifth bending film (275).
9. The cell of any one of claims 5-7, wherein, The insulating film (2) also includes: A second overlapping film (242) is connected to one side of the second film (22). The second overlapping film (242) is used to bend and cover the bottom surface and is bonded to the third film (23). A sixth bending film (276) is connected to the side of the second overlapping film (242) away from the third film (23). The sixth bending film (276) is used to cover part of the second bending surface, and a third notch (283) is provided between the sixth bending film (276) and the second bending film (272).
10. The cell of any one of claims 5-7, wherein, The insulating film (2) also includes: A third overlapping film (243), wherein adjacent sides of the third overlapping film (243) are respectively connected to the second film (22) and the third film (23), and a first folding slit (291) is cut on the second film (22) or the third overlapping film (243); or The third membrane (23) or the third overlapping membrane (243) has a second fold cut (292).