Insulating film of battery cell assembly and battery cell

Abstract

The utility model provides an insulating film of a battery cell assembly and a battery cell, the battery cell assembly is a winding type battery cell assembly, the insulating film comprises a bottom surface coverage area, a first side surface coverage area, a second side surface coverage area, a third side surface coverage area, a fourth side surface coverage area, a first overlapping coverage area and a second overlapping coverage area; the widths of the first overlapping coverage area and the second overlapping coverage area are smaller than the width of the corner part in the width direction of the battery cell assembly; when the insulating film is in a folded state, the first and second overlapping coverage areas overlap with the first and second overlapping portions of the first or second side coverage areas, respectively. A gap is formed between the corner part and the first side surface coverage area and between the corner part and the second side surface coverage area in the thickness direction of the battery cell assembly, and the gap accommodates the overlapped part of the insulating film and does not cause interference between the insulating film and the battery cell assembly, so that the overlapped part of the insulating film does not increase the space occupied by the insulating film in the thickness direction of the battery cell assembly; and the cell energy density is improved.

Description

Technical Field

[0001] This utility model relates to the field of batteries, and in particular to an insulating film and a battery cell for a battery cell assembly. Background Technology

[0002] Square batteries are a commonly used structure for lithium-ion power batteries. They consist of wound or stacked battery cells made of positive and negative electrodes and a separator, which are then assembled into a square casing before encapsulation. During the casing assembly process, because the casing is typically made of hard materials like aluminum or steel, its sharp edges and burrs pose a risk of scratching and damaging the battery cells. Therefore, before installing the battery cells into the casing, a soft and flexible insulating film (also called Mylar film) is used to cover the battery cells. This prevents direct contact between the battery cells and the outer aluminum casing, avoiding short circuits, aluminum corrosion, and damage to the battery cells caused by scratches from the aluminum casing.

[0003] The current insulation film assembly process is as follows: First, the bottom covering surface of the insulation film is heat-fused to the bottom support plate. Then, the large covering surface is bent on the long side of the bottom of the cell assembly to cover the larger side of the cell assembly. Next, the side covering surface is bent to wrap the smaller side of the cell assembly. Finally, the top points of the insulation film are heat-fused to the plastic under the cover plate of the cell to achieve full-range wrapping of the cell assembly.

[0004] The current insulating film structure overlaps and is fixed to the side of the cell assembly after folding. However, the overlapping part of the insulating film will cause the insulating film to occupy more space. As a result, the insulating film will occupy the space of the cell assembly while the internal space of the cell housing remains unchanged, which will reduce the energy density of the cell. Utility Model Content

[0005] The technical problem to be solved by this utility model is to overcome the defect in the prior art where the insulating film overlaps and is fixed on the side of the battery cell assembly after folding, resulting in the insulating film occupying too much space in the battery cell assembly and causing a reduction in the energy density of the battery cell. The present invention provides an insulating film and a battery cell for a battery cell assembly.

[0006] The present invention solves the above-mentioned technical problems through the following technical solution:

[0007] An insulating film for a battery cell assembly, the battery cell assembly being a wound battery cell assembly, the battery cell assembly including a main body and corner portions disposed at both ends of the main body along the width direction of the battery cell assembly, the battery cell assembly having a bottom surface, a first side surface and a second side surface spaced apart along the thickness direction of the battery cell assembly, a third side surface and a fourth side surface spaced apart along the width direction of the battery cell assembly, the insulating film of the battery cell assembly including a bottom surface covering area, a first side surface covering area, a second side surface covering area, a third side surface covering area, a fourth side surface covering area, a first overlapping covering area, and a second overlapping covering area;

[0008] The bottom surface covering area is used to cover the bottom surface;

[0009] The bottom covering area extends along a first direction to form the first side covering area, which is used to cover the first side; the bottom covering area extends along a second direction to form the second side covering area, which is used to cover the second side; the first direction and the second direction are two opposite directions in the thickness direction of the cell assembly;

[0010] One of the first side covering area and the second side covering area extends along a third direction to form the third side covering area, the third side covering area being used to cover the third side, and the other of the first side covering area and the second side covering area having a first overlapping portion at one end facing the third direction; one of the first side covering area and the second side covering area extends along a fourth direction to form the fourth side covering area, the fourth side covering area being used to cover the fourth side, and the other of the first side covering area and the second side covering area having a second overlapping portion at one end facing the fourth direction; the third direction and the fourth direction are two opposite directions in the width direction of the cell assembly;

[0011] The third side covering area extends along the third direction to form the first overlapping covering area. The width of the first overlapping covering area in the width direction of the cell assembly is smaller than the width of the corner portion on the corresponding side in the width direction of the cell assembly. When the insulating film of the cell assembly is in a folded state, the first overlapping covering area overlaps with the first overlapping portion.

[0012] The fourth side covering area extends along the fourth direction to form the second overlapping covering area, the width of the second overlapping covering area in the width direction of the cell assembly is smaller than the width of the corner portion on the corresponding side in the width direction of the cell assembly; when the insulating film of the cell assembly is in a folded state, the second overlapping covering area overlaps with the second overlapping portion.

[0013] In this design, because the battery cell assembly has a wound structure, rounded corners (i.e., corner portions) are formed on both sides of the width direction of the battery cell assembly. The thickness of the corner portion in the thickness direction of the battery cell assembly is less than the thickness of the main body portion in the thickness direction of the battery cell assembly. Therefore, during the assembly of the insulating film, a gap is formed between the corner portion and the first and second side covering areas in the thickness direction of the battery cell assembly. This gap provides space for the overlapping covering areas and overlapping portions to move in the thickness direction of the battery cell assembly. This gap can accommodate the overlapping portion of the insulating film without causing interference between the insulating film and the battery cell assembly, so that the overlapping portion of the insulating film does not increase the space occupied by the insulating film in the thickness direction of the battery cell assembly. Thus, without changing the internal space of the battery cell housing, the thickness dimension of the battery cell assembly can be designed to be larger, thereby improving the energy density of the battery cell.

[0014] Preferably, the width of the first overlapping coverage area in the width direction of the cell assembly is equal to the width of the second overlapping coverage area in the width direction of the cell assembly.

[0015] In this solution, the above-mentioned arrangement eliminates the need to distinguish the positional correspondence between the overlapping coverage area and the battery cell assembly when the insulating film is folded, thereby improving the assembly efficiency of the insulating film.

[0016] Preferably, the width of the first overlapping coverage area in the width direction of the cell assembly is defined as M, where M < H / (2*n*L);

[0017] Wherein, H is the thickness of the battery cell assembly, n is the number of cores in the battery cell assembly, and L is the width of the battery cell assembly.

[0018] In this solution, a range of dimensions for the width of the overlapping coverage area in the width direction of the cell assembly is provided to prevent the overlapping coverage area from being too wide and extending into the area corresponding to the main body of the cell assembly.

[0019] Preferably, when the insulating film of the battery cell assembly is in a folded state, the first overlapping covering area is disposed on the side of the first overlapping portion away from the bottom covering area in the thickness direction of the battery cell assembly, and the second overlapping covering area is disposed on the side of the second overlapping portion away from the bottom covering area in the thickness direction of the battery cell assembly, the first overlapping covering area covers the first overlapping portion, and the second overlapping covering area covers the second overlapping portion.

[0020] In this solution, the above assembly method enables the third side covering area and the fourth side covering area to limit the overlap in the width direction of the cell assembly, which facilitates the fixing of the overlapping covering area and the overlap.

[0021] Preferably, when the insulating film of the battery cell assembly is in a folded state, the first overlapping coverage area is disposed on the side of the first overlapping portion near the bottom surface coverage area in the thickness direction of the battery cell assembly, and the second overlapping coverage area is disposed on the side of the second overlapping portion near the bottom surface coverage area in the thickness direction of the battery cell assembly, the first overlapping portion covers the first overlapping coverage area, and the second overlapping portion covers the second overlapping coverage area.

[0022] In this solution, the above arrangement allows the overlapping coverage area to be accommodated within the gap between the corner and the first side coverage area (second side coverage area).

[0023] Preferably, the width of the bottom surface covering area facing the third direction in the thickness direction of the cell assembly is defined as a1, the width of the bottom surface covering area facing the fourth direction in the thickness direction of the cell assembly is a2, the width of the third side surface covering area in the width direction of the cell assembly is b, the width of the fourth side surface covering area in the width direction of the cell assembly is c, and the thickness of the insulating film of the cell assembly is t.

[0024] Where b = a1 - t, c = a2 - t.

[0025] In this solution, the above-mentioned arrangement ensures that the insulating film does not occupy more space in the thickness direction of the cell assembly when it is folded without being squeezed or deformed. Thus, the thickness of the cell assembly can be designed to be larger without changing the internal space of the cell housing, thereby improving the energy density of the cell.

[0026] Preferably, the insulating film of the battery cell assembly further includes a cover plate connecting portion for connecting with the cover plate of the battery cell;

[0027] The cover plate connection portion is located in one of the first overlapping coverage area and the first overlapping portion, which is away from the bottom surface coverage area in the thickness direction of the cell assembly; and / or, the cover plate connection portion is located in one of the second overlapping coverage area and the second overlapping portion, which is away from the bottom surface coverage area in the thickness direction of the cell assembly.

[0028] In this scheme, the above settings improve the connection strength between the overlapping coverage area and the overlapping part.

[0029] Preferably, the first side covering area extends along the third direction to form the third side covering area, the first side covering area extends along the fourth direction to form the fourth side covering area, the second side covering area has a first overlapping portion at one end facing the third direction, and the second side covering area has a second overlapping portion at one end facing the fourth direction.

[0030] In this scheme, both the first overlapping portion and the second overlapping portion are formed in the second side coverage area, and the first overlapping coverage area and the second overlapping coverage area are simultaneously fixed with the second side coverage area.

[0031] Preferably, the first side covering area extends along the third direction to form the third side covering area, the second side covering area extends along the fourth direction to form the fourth side covering area, the second side covering area has a first overlapping portion at the end facing the third direction, and the first side covering area has a second overlapping portion at the end facing the fourth direction.

[0032] In this scheme, the first overlapping portion and the second overlapping portion are formed in the second side coverage area and the first side coverage area, respectively, and the first overlapping coverage area and the second overlapping coverage area are fixed to the second side coverage area and the first side coverage area, respectively.

[0033] A battery cell includes a housing, a battery cell assembly, and an insulating film of the battery cell assembly as described above. The insulating film of the battery cell assembly covers the outer surface of the battery cell assembly, and both the battery cell assembly and the insulating film of the battery cell assembly are disposed inside the housing.

[0034] In this solution, the insulating film is used to cover the battery cell assembly before it is installed into the housing, preventing the housing from scratching or damaging the battery cell assembly during the installation process and avoiding damage to the battery cell assembly during assembly.

[0035] The significant advantages of this invention are as follows: Because the battery cell assembly has a wound structure, rounded corners (i.e., corner portions) are formed on both sides of the width direction. The thickness of these corner portions in the thickness direction is less than that of the main body in the same direction. Therefore, during the assembly of the insulating film, a gap is formed between the corner portions and the first and second side covering areas in the thickness direction of the battery cell assembly. This gap provides space for the overlapping covering areas and overlapping portions to move in the thickness direction of the battery cell assembly. This gap can accommodate the overlapping portion of the insulating film without causing interference between the insulating film and the battery cell assembly, ensuring that the overlapping portion of the insulating film does not increase the space occupied by the insulating film in the thickness direction of the battery cell assembly. Thus, without changing the internal space of the battery cell casing, a larger thickness dimension of the battery cell assembly can be designed to improve the battery cell energy density. Attached Figure Description

[0036] Figure 1 This is a three-dimensional structural diagram of the battery cell in Embodiment 1 of this utility model.

[0037] Figure 2This is a cross-sectional view of the assembly of the insulating film, battery cell assembly and cover plate in Embodiment 1 of this utility model.

[0038] Figure 3 This is a cross-sectional view of the assembly of the insulating film and the battery cell assembly in Embodiment 1 of this utility model.

[0039] Figure 4 This is a schematic diagram of the structure of the insulating film in the unfolded state of Embodiment 1 of this utility model.

[0040] Figure 5 This is a three-dimensional structural diagram of the insulating film in the folded state according to Embodiment 1 of this utility model.

[0041] Figure 6 This is a cross-sectional view of the assembly of the insulating film and the battery cell assembly in Embodiment 2 of this utility model.

[0042] Figure 7 This is a schematic diagram of the structure of the insulating film in the unfolded state of Embodiment 2 of this utility model.

[0043] Figure 8 This is a three-dimensional structural diagram of the insulating film in the folded state according to Embodiment 2 of this utility model.

[0044] Figure 9 This is a schematic diagram of the structure of the insulating film in the unfolded state of Embodiment 3 of this utility model.

[0045] Explanation of reference numerals in the attached figures:

[0046] Casing 1

[0047] Cover plate 2

[0048] Lower plastic 21

[0049] pole 3

[0050] Battery cell assembly 4

[0051] Main body 41

[0052] First corner section 42

[0053] Second corner 43

[0054] Bottom 44

[0055] Top surface 45

[0056] First side view 46

[0057] Second side 47

[0058] Third side 48

[0059] Fourth side 49

[0060] Core 410

[0061] Insulating film 5

[0062] Bottom Coverage Area 51

[0063] First side coverage area 52

[0064] Second side coverage area 53

[0065] Third side coverage area 54

[0066] Fourth side coverage area 55

[0067] First overlapping coverage area 56

[0068] Second overlapping coverage area 57

[0069] First overlapping part 58

[0070] Second overlapping part 59

[0071] Cover plate connection part 510

[0072] Overlapping part 511

[0073] Gap 6 Detailed Implementation

[0074] The present invention will be described more clearly and completely below with reference to the accompanying drawings, using a preferred embodiment.

[0075] Example 1

[0076] This embodiment provides a battery cell for supplying power to electrical equipment such as electric vehicles. Figure 1 and Figure 2 As shown, the battery cell includes a housing 1, a cover plate 2, terminals 3, a battery cell assembly 4, and an insulating film 5 covering the battery cell assembly 4. This embodiment uses a battery cell with terminals 3 at the top as an example. In other alternative embodiments, the battery cell can also be of other forms, such as a type with terminals 3 at both ends.

[0077] Specifically, such as Figure 1 and Figure 2As shown, the housing 1 is a hollow structure with an open top. The interior of the housing 1 has a cavity (not shown) for accommodating the battery cell assembly 4. A cover plate 2 covers the opening at the top of the housing 1 and completely seals it, ensuring that the cavity inside the housing 1 remains closed after the battery cell assembly 4 is inserted. A terminal post 3 is mounted on the cover plate 2 and is electrically connected to the battery cell assembly 4 to facilitate current transmission. A lower plastic insert 21, made of insulating material, is located on the lower part of the cover plate 2 (facing the cavity) to insulate the battery cell assembly 4. An insulating film 5 is used to cover the outer surface of the battery cell assembly 4 before it is inserted into the housing 1. After covering, the battery cell assembly 4 and the insulating film 5 are inserted together into the cavity inside the housing 1. The insulating film 5 protects the battery cell assembly 4, preventing scratches or other damage from the housing 1 during insertion and avoiding breakage during assembly.

[0078] like Figures 1-3 As shown, the battery cell assembly 4 in this embodiment is a wound battery cell assembly 4, which includes two cells in the thickness direction of the battery cell assembly 4. Figure 1 The cores 410 are stacked in the X direction of the battery cell assembly 4, and each core 410 is manufactured by a winding process. In other alternative embodiments, the number of cores 410 in the battery cell assembly 4 can be other, at least one, and when the number of cores 410 in the battery cell assembly 4 is multiple, the multiple cores 410 are stacked sequentially along the thickness direction of the battery cell assembly 4.

[0079] like Figure 3 As shown, the battery cell in this embodiment is a square battery cell, and the battery cell assembly 4 has a square wound structure. Specifically, the battery cell assembly 4 includes a main body 41 and corner portions located at both ends of the main body 41 along the width direction of the battery cell assembly 4. The corner portions are formed by the R-angle generated when the core 410 is wound. The main body 41 and the width direction of the battery assembly ( Figure 1 Parallel to the Y direction in the battery assembly, the main body 41 has two corner portions on either side of the battery assembly width direction, namely the first corner portion 42 and the second corner portion 43. It should be noted that since the battery cell assembly 4 in this embodiment includes two cores 410, the main body 41 in this embodiment is formed by combining the main body portions 41 of the two cores 410, and the corner portions are formed by combining the R-angles of the two cores 410.

[0080] like Figure 2 and Figure 3 As shown, the outer surface of the battery cell assembly 4 includes a bottom surface 44, a top surface 45, a first side surface 46 and a second side surface 47 spaced apart along the thickness direction of the battery cell assembly 4, and a third side surface 48 and a fourth side surface 49 spaced apart along the width direction of the battery cell assembly 4.

[0081] like Figures 3-5 As shown, the insulating film 5 of the battery cell assembly 4 includes a bottom surface covering area 51, a first side surface covering area 52, a second side surface covering area 53, a third side surface covering area 54, a fourth side surface covering area 55, a first overlapping covering area 56, and a second overlapping covering area 57.

[0082] When the insulating film 5 covers the battery cell assembly 4, the insulating film 5 is in a folded state. In this state, the bottom surface covering area 51 covers the bottom surface 44; the bottom surface covering area 51 is along the first direction ( Figure 4 The first side coverage area 52 extends along the X1 direction to form a first side coverage area 52, which covers the first side 46; the bottom coverage area 51 extends along the second direction ( Figure 4 The first side coverage area 52 extends along the third direction (X2 direction) to form a second side coverage area 53, which covers the second side 47; Figure 4 The first side coverage area 52 extends along the fourth direction (Y1 direction) to form a third side coverage area 54, which covers the third side 48; Figure 4 The fourth side coverage area 55 extends along the Y2 direction to form a fourth side coverage area 55, which covers the fourth side 49; the third side coverage area 54 extends along the third direction to form a first overlapping coverage area 56, which overlaps with a portion of the second side coverage area 53; the fourth side coverage area 55 extends along the fourth direction to form a second overlapping coverage area 57, which overlaps with a portion of the second side coverage area 53.

[0083] The first and second directions are two opposite orientations in the thickness direction of the cell assembly 4, and the third and fourth directions are two opposite orientations in the width direction of the cell assembly 4.

[0084] Specifically, such as Figure 3 and Figure 4 As shown, the corner portion of the battery cell assembly 4 facing the third direction is the first corner portion 42, and the corner portion of the battery cell assembly 4 facing the fourth direction is the second corner portion 43. The width of the first overlapping coverage area 56 in the width direction of the battery cell assembly 4 is smaller than the width of the first corner portion 42 in the width direction of the battery cell assembly 4, and the width of the second overlapping coverage area 57 in the width direction of the battery cell assembly 4 is smaller than the width of the second corner portion 43 in the width direction of the battery cell assembly 4. A first overlapping portion 58 is formed at the end of the second side coverage area 53 facing the third direction, and a second overlapping portion 59 is formed at the end of the second side coverage area 53 facing the fourth direction. When the insulating film 5 of the battery cell assembly 4 is in a folded state, the first overlapping coverage area 56 overlaps with the first overlapping portion 58, and the second overlapping coverage area 57 overlaps with the second overlapping portion 59. The overlapping areas of the overlapping coverage areas and overlapping portions can be connected by means of adhesive bonding or the like to fix the insulating film 5.

[0085] In this embodiment, both the first overlapping portion 58 and the second overlapping portion 59 are formed in the second side covering area 53, and the first overlapping covering area 56 and the second overlapping covering area 57 are simultaneously fixed to the second side covering area 53. In other alternative embodiments, one of the first overlapping portion 58 and the second overlapping portion 59 may be formed in the first side covering area 52, and the other may be formed in the second side covering area 53. In this state, one of the first side covering area 52 and the second side covering area 53 extends along a third direction to form a third side covering area 54, and the other of the first side covering area 52 and the second side covering area 53 extends along a fourth direction to form a fourth side covering area 55.

[0086] Furthermore, in this embodiment, when the insulating film 5 of the cell assembly 4 is in a folded state, the first overlapping covering area 56 is located on the side of the first overlapping portion 58 away from the bottom covering area 51 in the thickness direction of the cell assembly 4, and the second overlapping covering area 57 is located on the side of the second overlapping portion 59 away from the bottom covering area 51 in the thickness direction of the cell assembly 4. The first overlapping covering area 56 covers the first overlapping portion 58, and the second overlapping covering area 57 covers the second overlapping portion 59. That is, the first overlapping covering area 56 and the second overlapping covering area 57 are both located on the end face of the second side covering area 53 away from the first side covering area 52 in the thickness direction of the cell assembly 4. Thus, after the insulating film 5 is folded, the third side covering area 54 and the fourth side covering area 55 can limit the overlapping portion in the width direction of the cell assembly 4, which facilitates the fixing of the overlapping covering area and the overlapping portion.

[0087] In other alternative embodiments, the first overlapping coverage area 56 and the second overlapping coverage area 57 may both be disposed on one end face of the second side coverage area 53 facing the first side coverage area 52 in the thickness direction of the cell assembly 4. In this state, the second side coverage area 53 covers the first overlapping coverage area 56 and the second overlapping coverage area 57. Alternatively, one of the first overlapping coverage area 56 and the second overlapping coverage area 57 may be disposed on one end face of the second side coverage area 53 facing the first side coverage area 52 in the thickness direction of the cell assembly 4, and the other may be disposed on one end face of the second side coverage area 53 away from the first side coverage area 52 in the thickness direction of the cell assembly 4.

[0088] like Figure 4As shown, in this embodiment, the battery cell assembly 4 has the same width at both ends in the length direction, the first overlapping covering area 56 and the second overlapping covering area 57 have the same width in the width direction of the battery cell assembly 4, and the first corner portion 42 and the second corner portion 43 have the same width in the width direction of the battery cell assembly 4. Therefore, when folding the insulating film 5, it is not necessary to distinguish the positional correspondence between the overlapping covering area and the battery cell assembly 4, thereby improving the assembly efficiency of the insulating film 5.

[0089] Furthermore, such as Figure 3 As shown, the width of the corner portion in the width direction of the cell assembly 4 is defined as P, where P = H / (2*n*L). Here, H is the thickness of the cell assembly 4, n is the number of cores 410 in the cell assembly 4, and L is the width of the cell assembly 4. The width of the first overlapping coverage area 56 in the width direction of the cell assembly 4 is defined as M. In this embodiment, the width of the overlapping portion of the overlapping coverage area and the overlapping part in the width direction of the cell assembly 4 is less than P, i.e., M < H / (2*n*L). This embodiment limits the size range of the overlapping coverage area in the width direction of the cell assembly 4 to prevent the overlapping coverage area from becoming too wide and extending into the area corresponding to the main body portion 41 of the cell assembly 4.

[0090] In the commonly used core 410 size, the value of P is generally in the range of 8~20mm, for example, it can be 9mm, 9.125mm, 12.5mm, 13mm, 18mm, 18.25mm, etc.

[0091] In this embodiment, since the battery cell assembly 4 has a wound structure, R-angles (i.e., corner portions) are formed on both sides of the battery cell assembly 4 in the width direction. The thickness of the corner portion in the thickness direction of the battery cell assembly 4 is less than the thickness of the main body portion 41 in the thickness direction of the battery cell assembly 4. Therefore, during the assembly of the insulating film 5, a gap 6 is formed between the corner portion and the first side covering area 52 and the second side covering area 53 in the thickness direction of the battery cell assembly 4. This gap 6 provides space for the overlapping covering area and the overlapping portion to move in the thickness direction of the battery cell assembly 4. This gap 6 can accommodate the overlapping portion 511 of the insulating film 5 without causing interference between the insulating film 5 and the battery cell assembly 4, so that the overlapping portion 511 of the insulating film 5 does not increase the space occupied by the insulating film 5 in the thickness direction of the battery cell assembly 4. Thus, without changing the internal space of the battery cell housing 1, the thickness dimension of the battery cell assembly 4 can be designed to be larger to improve the energy density of the battery cell.

[0092] Furthermore, such as Figure 2 and Figure 5As shown, the cover plate 2 covers the top surface 45 of the battery cell assembly 4. The insulating film 5 also includes a cover plate connecting portion 510, which is located in the upper region of the insulating film 5 after the insulating film 5 is folded. The cover plate connecting portion 510 is used to heat-melt with the lower plastic 21 on the cover plate 2 of the battery cell to achieve the connection and fixation between the insulating film 5 and the cover plate 2. In this embodiment, there are multiple cover plate connecting portions 510, which strengthen the connection strength between the insulating film 5 and the cover plate 2 through multi-point fixing. Furthermore, both the first overlapping coverage area 56 and the second overlapping coverage area 57 have cover plate connecting portions 510. The connection between the cover plate connecting portion 510 and the cover plate 2 can further improve the connection strength between the overlapping coverage area and the overlapping portion.

[0093] To facilitate the connection between the insulating film 5 and the cover plate 2, the cover plate connecting portion 510 is located in one of the first overlapping coverage areas 56 and the first overlapping portion 58, which are away from the bottom surface coverage area 51 in the thickness direction of the cell assembly 4, and in one of the second overlapping coverage areas 57 and the second overlapping portion 59, which are also away from the bottom surface coverage area 51 in the thickness direction of the cell assembly 4. Since in this embodiment the first overlapping coverage area 56 and the second overlapping coverage area 57 are located on the outer side, the cover plate connecting portion 510 is located in the first overlapping coverage area 56 and the second overlapping coverage area 57. In other alternative embodiments, if the first overlapping portion 58 and the second overlapping portion 59 are located on the outer side, then the cover plate connecting portion 510 is located in the first overlapping portion 58 and the second overlapping portion 59.

[0094] In other alternative embodiments, the cover plate connecting part 510 may not be provided in the overlapping part of the overlapping coverage area and the overlapping part; its setting position is sufficient to achieve a stable connection between the insulating film 5 and the cover plate 2.

[0095] Example 2

[0096] The structure of the battery cell and insulating film 5 in this embodiment is basically the same as that in embodiment 1, except that:

[0097] like Figures 6-8As shown, the first side covering area 52 extends along a third direction to form a third side covering area 54; the second side covering area 53 extends along a fourth direction to form a fourth side covering area 55; a first overlapping portion 58 is formed at the end of the second side covering area 53 facing the third direction; and a second overlapping portion 59 is formed at the end of the first side covering area 52 facing the fourth direction. The third side covering area 54 extends along a third direction to form a first overlapping covering area 56, which overlaps with the first overlapping portion 58 on the second side covering area 53. The fourth side covering area 55 extends along the fourth direction to form a second overlapping covering area 57, which overlaps with the second overlapping portion 59 on the first side covering area 52. That is, in this embodiment, the first overlapping portion 58 and the second overlapping portion 59 are formed on the second side covering area 53 and the first side covering area 52, respectively, and the first overlapping covering area 56 and the second overlapping covering area 57 are fixed to the second side covering area 53 and the first side covering area 52, respectively.

[0098] Example 3

[0099] The structure of the battery cell and insulating film 5 in this embodiment is basically the same as that in embodiment 1, except that:

[0100] When the insulating film 5 of the cell assembly 4 is in a folded state, the first overlapping coverage area 56 is located on the side of the first overlapping portion 58 near the bottom coverage area 51 in the thickness direction of the cell assembly 4, and the second overlapping coverage area 57 is located on the side of the second overlapping portion 59 near the bottom coverage area 51 in the thickness direction of the cell assembly 4. The first overlapping portion 58 covers the first overlapping coverage area 56, and the second overlapping portion 59 covers the second overlapping coverage area 57. That is, the first overlapping coverage area 56 and the second overlapping coverage area 57 are located within the gap 6 formed by the second side coverage area 53 and the corner portion in the thickness direction of the cell assembly 4.

[0101] Furthermore, such as Figure 9 As shown, the width of the bottom covering area 51 facing the third direction in the thickness direction of the cell assembly 4 is defined as a1, the width of the bottom covering area 51 facing the fourth direction in the thickness direction of the cell assembly 4 is defined as a2, the width of the third side covering area 54 in the width direction of the cell assembly 4 is b, the width of the fourth side covering area 55 in the width direction of the cell assembly 4 is c, and the thickness of the insulating film 5 of the cell assembly 4 is t. Where b = a1 - t, c = a2 - t. Specifically, in this embodiment, the thickness of the bottom covering area 51 at both ends in the width direction of the cell assembly 4 is the same, i.e., a1 = a2, b = c.

[0102] The first overlapping coverage area 56 and the second overlapping coverage area 57 utilize the extra space in the thickness direction of the corner portion of the cell assembly 4, so that the insulating film 5 does not occupy more space in the thickness direction of the cell assembly 4 when it is not squeezed and deformed. Thus, the thickness dimension of the cell assembly 4 can be designed to be larger without changing the internal space of the cell housing 1, thereby improving the energy density of the cell.

[0103] Furthermore, in this embodiment, since the second side covering area 53 covers the first overlapping covering area 56 and the second overlapping covering area 57, the cover plate connecting portion 510 is located on the first overlapping portion 58 and the second overlapping portion 59 in the second side covering area 53.

[0104] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship of the device or component shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0105] While specific embodiments of this utility model have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of this utility model is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of this utility model, but all such changes and modifications fall within the scope of protection of this utility model.

Claims

1. An insulating film for a battery cell assembly, the battery cell assembly being a wound battery cell assembly, the battery cell assembly comprising a main body and corner portions disposed at both ends of the main body along the width direction of the battery cell assembly, the battery cell assembly having a bottom surface, a first side surface and a second side surface spaced apart along the thickness direction of the battery cell assembly, and a third side surface and a fourth side surface spaced apart along the width direction of the battery cell assembly, characterized in that, The insulating film of the battery cell assembly includes a bottom covering area, a first side covering area, a second side covering area, a third side covering area, a fourth side covering area, a first overlapping covering area, and a second overlapping covering area. The bottom surface covering area is used to cover the bottom surface; The bottom covering area extends along a first direction to form the first side covering area, which is used to cover the first side; the bottom covering area extends along a second direction to form the second side covering area, which is used to cover the second side; the first direction and the second direction are two opposite directions in the thickness direction of the cell assembly; One of the first side covering area and the second side covering area extends along a third direction to form the third side covering area, the third side covering area being used to cover the third side, and the other of the first side covering area and the second side covering area having a first overlapping portion at one end facing the third direction; one of the first side covering area and the second side covering area extends along a fourth direction to form the fourth side covering area, the fourth side covering area being used to cover the fourth side, and the other of the first side covering area and the second side covering area having a second overlapping portion at one end facing the fourth direction; the third direction and the fourth direction are two opposite directions in the width direction of the cell assembly; The third side covering area extends along the third direction to form the first overlapping covering area. The width of the first overlapping covering area in the width direction of the cell assembly is smaller than the width of the corner portion on the corresponding side in the width direction of the cell assembly. When the insulating film of the cell assembly is in a folded state, the first overlapping covering area overlaps with the first overlapping portion. The fourth side covering area extends along the fourth direction to form the second overlapping covering area, the width of the second overlapping covering area in the width direction of the cell assembly is smaller than the width of the corner portion on the corresponding side in the width direction of the cell assembly; when the insulating film of the cell assembly is in a folded state, the second overlapping covering area overlaps with the second overlapping portion.

2. The insulating film of the battery cell assembly as described in claim 1, characterized in that, The width of the first overlapping coverage area in the width direction of the cell assembly is equal to the width of the second overlapping coverage area in the width direction of the cell assembly.

3. The insulating film of the battery cell assembly as described in claim 2, characterized in that, The width of the first overlapping coverage area in the width direction of the cell assembly is defined as M, where M < H / (2*n*L); Wherein, H is the thickness of the battery cell assembly, n is the number of cores in the battery cell assembly, and L is the width of the battery cell assembly.

4. The insulating film of the cell assembly as described in claim 1, characterized in that, When the insulating film of the battery cell assembly is in a folded state, the first overlapping covering area is located on the side of the first overlapping portion away from the bottom covering area in the thickness direction of the battery cell assembly, and the second overlapping covering area is located on the side of the second overlapping portion away from the bottom covering area in the thickness direction of the battery cell assembly. The first overlapping covering area covers the first overlapping portion, and the second overlapping covering area covers the second overlapping portion.

5. The insulating film of the battery cell assembly as described in claim 1, characterized in that, When the insulating film of the battery cell assembly is in a folded state, the first overlapping coverage area is located on the side of the first overlapping portion near the bottom coverage area in the thickness direction of the battery cell assembly, and the second overlapping coverage area is located on the side of the second overlapping portion near the bottom coverage area in the thickness direction of the battery cell assembly. The first overlapping portion covers the first overlapping coverage area, and the second overlapping portion covers the second overlapping coverage area.

6. The insulating film of the battery cell assembly as described in claim 5, characterized in that, The width of the bottom surface covering area facing the third direction in the thickness direction of the cell assembly is defined as a1, the width of the bottom surface covering area facing the fourth direction in the thickness direction of the cell assembly is defined as a2, the width of the third side surface covering area in the width direction of the cell assembly is defined as b, the width of the fourth side surface covering area in the width direction of the cell assembly is defined as c, and the thickness of the insulating film of the cell assembly is defined as t. Where b = a1 - t, c = a2 - t.

7. The insulating film of the cell assembly as described in claim 4 or 5, characterized in that, The insulating film of the battery cell assembly also includes a cover plate connecting portion, which is used to connect with the cover plate of the battery cell. The cover plate connection portion is located in one of the first overlapping coverage area and the first overlapping portion, which is away from the bottom surface coverage area in the thickness direction of the cell assembly; and / or, the cover plate connection portion is located in one of the second overlapping coverage area and the second overlapping portion, which is away from the bottom surface coverage area in the thickness direction of the cell assembly.

8. The insulating film of the battery cell assembly as described in claim 1, characterized in that, The first side coverage area extends along the third direction to form the third side coverage area, the first side coverage area extends along the fourth direction to form the fourth side coverage area, the second side coverage area has a first overlapping portion at one end facing the third direction, and the second side coverage area has a second overlapping portion at one end facing the fourth direction.

9. The insulating film of the cell assembly as described in claim 1, characterized in that, The first side coverage area extends along the third direction to form the third side coverage area, the second side coverage area extends along the fourth direction to form the fourth side coverage area, the second side coverage area has a first overlapping portion at the end facing the third direction, and the first side coverage area has a second overlapping portion at the end facing the fourth direction.

10. A battery cell, characterized in that, The device includes a housing, a cell assembly, and an insulating film for the cell assembly as described in any one of claims 1-9, wherein the insulating film of the cell assembly covers the outer surface of the cell assembly, and both the cell assembly and the insulating film of the cell assembly are disposed inside the housing.

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