CN219739088U - Insulating film of battery cell casing, battery cell and secondary battery - Google Patents

Abstract

The utility model provides an insulating film of a battery cell shell, a battery cell and a secondary battery, wherein the insulating film is of an integrated structure, a bottom surface coverage area of the insulating film extends towards a first side surface to form a first side surface coverage area, the bottom surface coverage area extends towards a second side surface to form a second side surface coverage area, the first side surface coverage area extends towards a third side surface to form a third side surface coverage area, and the third side surface coverage area is used for covering part of the third side surface; the second side coverage area extends toward the third side to form a fourth side coverage area for covering a portion of the third side; the third side coverage area is connected to the fourth side coverage area portion such that the third side portion is exposed. The exposed part of the third side surface can be connected with a battery shell of the secondary battery or other adjacent battery cells, so that the connection strength between the battery cells and the battery shell of the secondary battery or between the battery cells is improved, the vibration resistance of the secondary battery is enhanced, and the service life of the secondary battery is prolonged.

Description

Insulating film of battery cell casing, battery cell and secondary battery

Technical Field

The utility model relates to the technical field of batteries, in particular to an insulating film of a battery cell shell, a battery cell and a secondary battery.

Background

Secondary batteries generally include a plurality of cells arranged in series and a case for accommodating the plurality of cells, and since the cells expand during operation, particularly toward the direction in which the plurality of cells are arranged, the plurality of cells are pressed against each other to affect the performance and the service life of the cells. In order to solve the problem of expansion, a gap is generally provided between two adjacent cells in the prior art, but this approach cannot achieve mutual fixation between the cells, so that the cells need to be further mounted on the case of the secondary battery. In order to improve the insulation of the battery cell, the outer periphery of the battery cell case is generally covered with an insulating film, but the insulating film cannot be fixed to the case of the secondary battery. When the secondary battery is impacted, the battery cell is easily separated from the case of the secondary battery, resulting in failure of the secondary battery.

Disclosure of Invention

The utility model aims to overcome the defect that in the prior art, an insulating film coated on the periphery of a battery cell shell cannot be fixed with a shell of a secondary battery, so that the connection strength of a battery cell and the secondary battery is poor.

The utility model solves the technical problems by the following technical scheme:

the insulation film of the battery cell shell comprises a bottom surface, a first side surface, a second side surface, a third side surface and a fourth side surface, wherein the first side surface and the second side surface are opposite, the third side surface and the fourth side surface are opposite, the insulation film of the battery cell shell is of an integrally formed structure, and the insulation film of the battery cell shell comprises a bottom surface coverage area, a first side surface coverage area, a second side surface coverage area, a third side surface coverage area and a fourth side surface coverage area;

the bottom surface coverage area is used for covering at least part of the bottom surface;

the bottom surface coverage area extends towards the first side surface to form the first side surface coverage area, and the first side surface coverage area is used for covering the first side surface; the bottom surface coverage area extends towards the second side surface to form the second side surface coverage area, and the second side surface coverage area is used for covering the second side surface;

the first side coverage area extending toward the third side to form the third side coverage area, the third side coverage area for covering a portion of the third side; the second side coverage area extending toward the third side to form the fourth side coverage area for covering a portion of the third side; the third side coverage area is connected to the fourth side coverage area portion such that the third side portion is exposed.

In the scheme, the third side surface coverage area and the fourth side surface coverage area of the insulating film are partially connected so that the third side surface of the battery cell shell is not completely covered by the insulating film, the exposed part of the third side surface can be connected with the battery shell of the secondary battery or other adjacent battery cells, the connection strength of the battery cells and the battery shell of the secondary battery or the connection strength between the battery cells is improved, the vibration resistance of the secondary battery is enhanced, and the service life of the secondary battery is prolonged. In addition, because the insulating film is integrated into one piece's structure, compare in adopting the insulating film of equidimension to splice, can reduce material and process cost.

Preferably, the third side coverage area includes a first film body and a first extension portion, the fourth side coverage area includes a second film body, the first film body and the second film body are arranged at intervals on the third side, the first film body extends towards one end of the second film body towards the direction of the second film body to form the first extension portion, and the first extension portion is connected with the second film body.

In this scheme, thereby the interval sets up between first membrane body and the second membrane body and makes the third side of electric core casing can partly expose to be connected through first extension and second membrane body and increase the creepage distance between part and the battery casing electric connecting piece that the third side of electric core exposes.

Preferably, the fourth side coverage area further includes a second extension portion, one end of the second film body facing the first film body extends toward the first film body to form the second extension portion, and the second extension portion is connected with the first film body.

In the scheme, the creepage distance between the exposed part of the third side surface of the battery cell and the battery shell electric connecting piece is increased through the connection of the second extension part and the first film body.

Preferably, the first extension portion and the second extension portion are located on the same side of the third side surface, and the first extension portion and the second extension portion are connected.

In this scheme, above-mentioned setting can shorten the length of single first extension, and then reduces the degree of difficulty of pad pasting, improves the roughness of pad pasting, prevents to produce and opens and warp and air circuit phenomenon.

Preferably, the first extension and the second extension are partially overlapped.

In this scheme, above-mentioned setting increases the creepage distance between the part that the third side of electric core exposes and the battery casing electrical connector.

Preferably, the third side coverage area and the fourth side coverage area are symmetrically arranged on the third side.

In this scheme, the alignment process before the insulating film cladding can be simplified to above-mentioned setting, improves the cladding efficiency of insulating film.

Preferably, the first film body and the second film body are arranged at intervals in a first direction, and the first direction is an interval direction of the first side coverage area and the second side coverage area.

In this scheme, a specific setting mode of first membrane body and second membrane body is provided.

Preferably, the insulating film of the battery cell casing further includes a fifth side coverage area, the bottom coverage area extends toward the third side to form the fifth side coverage area, the fifth side coverage area is used for covering a part of the third side, and the third side coverage area and the fourth side coverage area are connected with the fifth side coverage area;

the first extension part is arranged at one end of the first film body far away from the bottom surface coverage area.

In this scheme, the region of fifth side coverage area is used for covering third side bottom to increase the creepage distance between the part that the third side of electric core exposes and the battery casing electrical connector. The first extension part is arranged at one end of the first film body far away from the coverage area of the bottom surface, so that a space can be reserved between the first extension part and the coverage area of the fifth side surface, and the third side surface of the battery cell shell can be partially exposed.

The battery cell comprises a battery cell shell, a battery cell assembly and the insulating film of the battery cell shell, wherein the battery cell assembly is accommodated in the battery cell shell, and the insulating film of the battery cell shell is coated on the outer surface of the battery cell shell;

the outer surface of the battery cell shell comprises a bottom surface, a first side surface, a second side surface, a third side surface and a fourth side surface, wherein the first side surface and the second side surface are opposite; the bottom surface coverage area covers at least part of the bottom surface, the first side surface coverage area covers the first side surface, the second side surface coverage area covers the second side surface, the third side surface coverage area covers part of the third side surface, and the fourth side surface coverage area covers part of the third side surface;

the third side surface part is exposed to form a connecting part of the battery cell shell, and the connecting part is used for external connection.

In this scheme, the insulating film cladding is on the surface of electric core casing to play insulating effect to the electric core, the part that the third side of electric core casing exposes forms the connecting portion that is used for with external connection, and the battery casing of secondary cell or other adjacent electric cores of connection can be connected to the connecting portion, with the joint strength of improving electric core and the battery casing of secondary cell or the joint strength between electric core and the electric core, reinforcing secondary cell's shock resistance ability, extension secondary cell's life.

The secondary battery comprises a battery shell and a plurality of electric cores, wherein the battery shell is provided with an accommodating cavity, the electric cores are accommodated in the accommodating cavity, the electric cores are sequentially arranged along a first direction, and the connecting parts of the electric cores are adhered to the inner wall of the accommodating cavity or the adjacent electric cores; the first direction is the direction of separation of the first side coverage area and the second side coverage area.

In the scheme, the connecting part of the battery core is connected with the shell of the secondary battery, so that the connection strength of the battery core and the battery shell of the secondary battery can be improved, the vibration resistance of the secondary battery is enhanced, and the service life of the secondary battery is prolonged.

The utility model has the positive progress effects that: the third side surface coverage area and the fourth side surface coverage area of the insulating film are partially connected so that the third side surface of the battery cell shell is not completely covered by the insulating film, the exposed part of the third side surface can be connected with the battery shell of the secondary battery or other adjacent battery cells, the connection strength of the battery cell and the battery shell of the secondary battery or the connection strength between the battery cell and the battery cell is improved, the vibration resistance of the secondary battery is enhanced, and the service life of the secondary battery is prolonged. In addition, because the insulating film is integrated into one piece's structure, compare in adopting the insulating film of equidimension to splice, can reduce material and process cost.

Drawings

Fig. 1 is a schematic view illustrating an internal structure of a secondary battery according to an embodiment of the present utility model.

Fig. 2 is a schematic perspective view of a battery cell according to an embodiment of the utility model.

Fig. 3 is a schematic view illustrating an unfolded state of an insulating film of a battery cell housing according to an embodiment of the utility model.

Fig. 4 is a schematic diagram illustrating steps of a coating process of an insulating film and a battery cell housing according to an embodiment of the utility model.

Fig. 5 is a schematic diagram illustrating another step of the coating process of the insulating film and the battery cell housing according to an embodiment of the utility model.

Fig. 6 is a schematic diagram illustrating another step of the coating process of the insulating film and the battery cell housing according to an embodiment of the utility model.

Fig. 7 is a schematic diagram illustrating another step of the coating process of the insulating film and the battery cell housing according to an embodiment of the utility model.

Fig. 8 is a schematic diagram illustrating another step of the coating process of the insulating film and the battery cell housing according to an embodiment of the utility model.

Fig. 9 is a schematic diagram illustrating another step of the coating process of the insulating film and the battery cell housing according to an embodiment of the utility model.

Reference numerals illustrate:

battery case 1

Accommodating chamber 11

Cell 2

Cell casing 21

Top surface 211

Bottom surface 212

First side 213

Second side 214

Third side 215

Fourth side 216

Connection portion 217

Insulating film 3

Top surface coverage area 31

Bottom surface footprint 32

First side coverage area 33

Second side coverage area 34

Third side coverage area 35

First film body 351

First extension 352

Fourth side coverage area 36

Second film body 361

Second extension 362

Fifth side footprint 37

Notch 38

First side edge 41

Second side edge 42

First crease line 43

First crease section 431

Second crease section 432

Second crease line 44

Third crease section 441

Fourth crease segment 442

Third crease line 45

Fifth crease section 451

Sixth crease section 452

Detailed Description

The present utility model will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments are shown.

As shown in fig. 1 and 2, the present embodiment discloses a secondary battery for supplying power to electric equipment such as an electric automobile. The secondary battery includes a battery case 1 and a plurality of battery cells 2, the battery case 1 being for receiving and protecting the plurality of battery cells 2.

As shown in fig. 1, the battery case 1 has an accommodating cavity 11 inside, and a plurality of battery cells 2 are accommodated in the accommodating cavity 11, and the battery cells 2 are fixedly connected with the battery case 1, so as to prevent the battery cells 2 from being separated from the battery case 1, and avoid the failure of the secondary battery.

As shown in fig. 2 and 4, the battery cell 2 includes a battery cell housing 21, a battery cell assembly (not shown in the drawings) and an insulating film 3 of the battery cell housing 21, the battery cell assembly is accommodated in the battery cell housing 21, and the insulating film 3 of the battery cell housing 21 is coated on the outer surface of the battery cell housing 21. Specifically, the outer surface of the cell case 21 includes a top surface 211, a bottom surface 212, first and second side surfaces 213 and 214 disposed opposite to each other in the second direction (Y direction in fig. 2), and third and fourth side surfaces 215 and 216 disposed opposite to each other in the first direction (X direction in fig. 2). In this embodiment, the battery cell housing 21 has a rectangular structure, the widths of the first side 213 and the second side 214 are equal, the widths of the third side 215 and the fourth side 216 are equal, and the widths of the first side 213 and the second side 214 are greater than the widths of the third side 215 and the fourth side 216. The first direction is a direction of spacing between the first side 213 and the second side 214, the second direction is a direction of spacing between the third side 215 and the fourth side 216, and the first direction is perpendicular to the second direction.

As shown in fig. 1, the plurality of cells 2 are arranged in sequence in the first direction, i.e., for two adjacent cells 2, the first side 213 of one cell housing 21 is adjacent to the second side 214 of the other cell housing 21. The third side 215 and the fourth side 216 of the battery cell housing 21 are respectively provided with a connecting part 217 exposed out of the insulating film 3, and the third side 215 and the fourth side 216 are directly adhered to the inner wall of the accommodating cavity 11 at the corresponding side through the connecting part 217 so as to realize the fixed connection of the battery cell 2 and the battery housing 1.

In other alternative embodiments, only the third side 215 or the fourth side 216 of the battery case 21 may be provided with the connecting portion 217 adhered to the inner wall of the accommodating cavity 11, and in this embodiment, the third side 215 and the fourth side 216 of the battery case 21 are provided with the connecting portion 217 adhered to the inner wall of the accommodating cavity 11, so as to further enhance the connection strength between the battery cell 2 and the battery case 1, enhance the vibration resistance of the secondary battery, and prolong the service life of the secondary battery.

In other alternative embodiments, the plurality of cells 2 may also be arranged in the second direction, in which case the connection 217 on the third side 215 and the fourth side 216 may be used for bonding between adjacent cells 2. Alternatively, the connection 217 on the third side 215 and the fourth side 216 may also be used for connection with other external components.

In the following, the connection portion 217 formed on the third side surface 215 will be described as an example, and the connection portion 217 on the fourth side surface 216 may be molded in the same manner.

As shown in fig. 2, the insulating film 3 of the cell case 21 in the present embodiment is an integrally formed structure including a top surface coverage area 31, a bottom surface coverage area 32, a first side surface coverage area 33, a second side surface coverage area 34, a third side surface coverage area 35, a fourth side surface coverage area 36, and a fifth side surface coverage area 37. When the insulating film 3 is wrapped around the cell case 21, the insulating film 3 is in a use state. In this state, the bottom surface coverage area 32 completely covers the bottom surface 212; the bottom surface footprint 32 extends toward the first side 213 to form a first side footprint 33, the first side footprint 33 completely encasing the first side 213; the bottom surface footprint 32 extends toward the second side 214 to form a second side footprint 34, the second side footprint 34 completely encasing the second side 214; the bottom surface footprint 32 extends toward the third side 215 to form a fifth side footprint 37, the fifth side footprint 37 being configured to cover a portion of the third side 215; the first side coverage area 33, the second side coverage area 34, the third side coverage area 35, and the fourth side coverage area 36 extend toward the top surface 211 to form a top surface coverage area 31, with the top surface coverage area 31 covering a portion of the top surface 211. Wherein the first direction is also the direction in which the first side coverage area 33 and the second side coverage area 34 are spaced apart. In other alternative embodiments, the floor covering 32 may also only partially cover the floor 212.

As shown in fig. 2, the third side covering area 35 covers part of the third side 215, the fourth side covering area 36 covers part of the third side 215, and the third side covering area 35 is partially connected to the fourth side covering area 36 so that part of the third side 215 is exposed to form the connection portion 217.

Specifically, as shown in fig. 3, the insulating film 3 has a planar structure in the developed state, and has two first side edges 41 that are spaced apart in the first direction, two second side edges 42 that are spaced apart in the second direction, two first crease lines 43 that extend in the first direction and are spaced apart, two second crease lines 44 that extend in the second direction and are spaced apart, and two third crease lines 45 that extend in the second direction and are spaced apart, and the two second crease lines 44 are disposed between the two third crease lines 45. Two ends of the two second side edges 42 are respectively connected with the first side edges 41 of the corresponding sides, two ends of the two first crease lines 43 respectively extend to the two first side edges 41, two ends of the two second crease lines 44 respectively extend to the two second side edges 42, and two ends of the two third crease lines 45 respectively extend to the two second side edges 42.

The first crease line 43 is separated by two second crease lines 44 into a first crease section 431 and two second crease sections 432, and the two second crease sections 432 are connected to two ends of the first crease section 431. The second crease line 44 is separated by two first crease lines 43 into a third crease section 441 and two fourth crease sections 442, and the two fourth crease sections 442 are connected to two ends of the second crease section 432. The third crease line 45 is separated by two first crease lines 43 into a fifth crease section 451 and two sixth crease sections 452, and the two fifth crease sections 451 are connected to two ends of the sixth crease section 452.

The first crease section 431 and the third crease section 441 enclose the bottom surface coverage area 32 of the insulating film 3, the second crease section 432, the third crease section 441 and the fifth crease section 451 enclose the first side surface coverage area 33 and the second side surface coverage area 34 of the insulating film 3, the second crease section 432, the fourth crease section 442, the sixth crease section 452 and the second side edge 42 enclose the third side surface coverage area 35 and the fourth side surface coverage area 36 of the insulating film 3, the first crease section 431, the fourth crease section 442 and the first side edge 41 enclose the fifth side surface coverage area 37, the third crease line 45, the second side edge 42 and the first side edge 41 enclose the top surface coverage area 31 of the insulating film 3, and the top surface coverage area 31 is located on a side of the first side surface coverage area 33 and the second side surface coverage area 34 away from the bottom surface coverage area 32.

In this embodiment, the insulating film 3 is coated on the outer surface of the cell case 21 to insulate the cell 2. The third side surface coverage area 35 and the fourth side surface coverage area 36 of the insulating film 3 are partially connected so that the third side surface 215 of the battery cell housing 21 is not completely covered by the insulating film 3, and the connection portion 217 exposed from the third side surface 215 can be connected with the battery housing 1 of the secondary battery, so that the connection strength of the battery cell 2 and the battery housing 1 of the secondary battery is improved, the vibration resistance of the secondary battery is enhanced, and the service life of the secondary battery is prolonged. In addition, because the insulating film 3 is an integrally formed structure, material and process costs can be reduced compared with splicing by using insulating films 3 of different sizes.

As shown in fig. 3 and 5-7, the third side covering area 35 includes a first film body 351 and a first extension portion 352, where the first film body 351 extends toward the second film body 361 toward one end of the second film body 361 to form the first extension portion 352, and the first extension portion 352 is connected to the second film body 361. The fourth side covering area 36 includes a second film body 361 and a second extending portion 362, where the first film body 351 and the second film body 361 are disposed at intervals on the third side 215, the second film body 361 extends toward one end of the first film body 351 to form the second extending portion 362 in the direction of the first film body 351, and the second extending portion 362 is connected to the first film body 351. In this embodiment, the first film body 351 and the second film body 361 are disposed at intervals, so that the third side 215 of the battery case 21 can be partially exposed, the creepage distance between the exposed portion of the third side 215 of the battery cell 2 and the electrical connector of the battery case 1 is increased by connecting the first extension portion 352 and the second film body 361, and the creepage distance between the exposed portion of the third side 215 of the battery cell 2 and the electrical connector of the battery case 1 is increased by connecting the second extension portion 362 and the first film body 351.

Specifically, the first extension portion 352 and the second extension portion 362 are located on the same side of the third side 215, the first extension portion 352 is disposed at an end of the first film body 351 away from the bottom coverage area 32, and the first extension portion 352 is connected to the top coverage area 31, so that a space can be provided between the third extension portion and the fifth side coverage area 37. The second extension portion 362 is disposed at one end of the second film body 361 far away from the bottom coverage area 32, the second extension portion 362 is connected with the top coverage area 31, so that a space can be provided between the second extension portion 362 and the fifth side coverage area 37, the first extension portion 352 and the second extension portion 362 are connected and partially overlapped, and further the third side 215 of the battery cell housing 21 can be partially exposed, and the length of a single first extension portion 352 or a single second extension portion 362 can be shortened, so that the difficulty of film pasting is reduced, the flatness of the film pasting is improved, and the phenomena of warping and air paths are prevented.

Specifically, as shown in fig. 3, the notch 38 is cut out on the third side coverage area 35 and the fourth side coverage area 36, the notch 38 is formed to be recessed inward from an end of the third side coverage area 35 away from the first side coverage area 33 (also an end of the fourth side coverage area 36 away from the second side coverage area 34), the notch 38 located on the same side (the third side 215 or the fourth side 216) of the cell case 21 extends from the third side coverage area 35 to the fourth side coverage area 36 in the first direction, thereby forming the first extension portion 352 and the second extension portion 362. The size of the notch 38 and the size of the notch can be cut according to actual requirements, so that the size of the connecting portion 217 can be adjusted, and the suitability of the insulating film 3 is improved.

Preferably, the third side coverage area 35 and the fourth side coverage area 36 are symmetrically disposed on the third side 215, that is, the first film body 351 and the second film body 361 are symmetrical, and the first extension portion 352 and the second extension portion 362 are symmetrical, so as to simplify the alignment process before the insulating film 3 is coated, and improve the coating efficiency of the insulating film 3.

In other alternative embodiments, the first extension 352 may be disposed only within the third side coverage area 35, the first extension 352 being directly connected to the second film body 361; or only the second extension 362 is provided in the fourth side coverage area 36, the second extension 362 being directly connected with the first film body 351.

The following process of coating the insulating film 3 on the cell case 21 is briefly described in connection with the specific structures of the insulating film 3 and the cell case 21 described above:

step 1: as shown in fig. 4, the rectangular insulating film 3 is selected first, and the bottom surface 212 of the cell case 21 is placed in the bottom coverage area of the insulating film 3.

Step 2: as shown in fig. 5, a notch 38 is cut out in the insulating film 3.

It should be appreciated that in other alternative embodiments, step 2 may be performed first, followed by step 1.

Step 3: as shown in fig. 6, the insulating films 3 located on both sides of the cell case 21 in the first direction are bent toward the first side surface 213 and the second side surface 214, respectively, to entirely cover the first side surface 213 and the second side surface 214.

Step 4: as shown in fig. 7, the fifth side covering area 37 is bent toward the third side 215 to cover the bottom area of the third side 215.

Step 5: as shown in fig. 8 and 9, the first film body 351 and the second film body 361 are folded in the direction of the third side surface 215 to cover part of the third side surface 215, respectively. The first extension portion 352 and the second extension portion 362 partially overlap, and the first extension portion 352, the second extension portion 362, and the fifth side coverage area 37 enclose a space in which the third side 215 is exposed. In other alternative embodiments, the first film body 351 and the second film body 361 may be folded first, and then the fifth side coverage 37 may be folded.

Step 7: as shown in fig. 2, the top surface covering area 31 is folded toward the top surface 211 of the cell case 21 and covers a part of the top surface 211.

In the description of the present utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the devices or components shown in the drawings, are merely for convenience in describing the present utility model and simplifying the description, and do not indicate or imply that the devices or components referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present utility model.

While specific embodiments of the utility model have been described above, it will be appreciated by those skilled in the art that this is by way of example only, and the scope of the utility model is defined by the appended claims. Various changes and modifications to these embodiments may be made by those skilled in the art without departing from the principles and spirit of the utility model, but such changes and modifications fall within the scope of the utility model.

Claims (10)

1. The insulating film of the battery cell shell comprises a bottom surface, a first side surface, a second side surface, a third side surface and a fourth side surface, wherein the first side surface, the second side surface, the third side surface and the fourth side surface are opposite;

the bottom surface coverage area is used for covering at least part of the bottom surface;

the bottom surface coverage area extends towards the first side surface to form the first side surface coverage area, and the first side surface coverage area is used for covering the first side surface; the bottom surface coverage area extends towards the second side surface to form the second side surface coverage area, and the second side surface coverage area is used for covering the second side surface;

the first side coverage area extending toward the third side to form the third side coverage area, the third side coverage area for covering a portion of the third side; the second side coverage area extending toward the third side to form the fourth side coverage area for covering a portion of the third side; the third side coverage area is connected to the fourth side coverage area portion such that the third side portion is exposed.

2. The insulating film of a cell housing of claim 1, wherein the third side cover comprises a first film body and a first extension, the fourth side cover comprises a second film body, the first film body and the second film body are disposed at intervals on the third side, the first film body extends toward one end of the second film body toward the second film body to form the first extension, and the first extension is connected to the second film body.

3. The insulating film of a cell housing of claim 2, wherein the fourth side cover further comprises a second extension, the second extension being formed by extending the second film body toward the first film body, the second extension being connected to the first film body.

4. The insulating film of claim 3, wherein said first extension and said second extension are on the same side of said third side, said first extension and said second extension being connected.

5. The insulating film of a cell housing of claim 4, wherein the first extension and the second extension partially overlap.

6. The insulating film of a cell housing of claim 4, wherein said third side cover region and said fourth side cover region are symmetrically disposed on said third side.

7. The insulating film of any of claims 2-6, wherein said first film body and said second film body are spaced apart in a first direction, the first direction being the direction of spacing of said first side footprint and said second side footprint.

8. The insulating film of a cell housing of claim 7, further comprising a fifth side coverage area, said bottom coverage area extending toward said third side to form said fifth side coverage area, said fifth side coverage area being for covering a portion of said third side, said third side coverage area and said fourth side coverage area being connected to said fifth side coverage area portion;

the first extension part is arranged at one end of the first film body far away from the bottom surface coverage area.

9. A battery cell, comprising a battery cell housing, a battery cell assembly and an insulating film of the battery cell housing according to any one of claims 1-8, wherein the battery cell assembly is accommodated in the battery cell housing, and the insulating film of the battery cell housing is coated on the outer surface of the battery cell housing;

the outer surface of the battery cell shell comprises a bottom surface, a first side surface, a second side surface, a third side surface and a fourth side surface, wherein the first side surface and the second side surface are opposite; the bottom surface coverage area covers at least part of the bottom surface, the first side surface coverage area covers the first side surface, the second side surface coverage area covers the second side surface, the third side surface coverage area covers part of the third side surface, and the fourth side surface coverage area covers part of the third side surface;

the third side surface part is exposed to form a connecting part of the battery cell shell, and the connecting part is used for external connection.

10. A secondary battery comprising a battery case and a plurality of the cells according to claim 9, wherein the battery case has a housing chamber in which the plurality of cells are housed, the plurality of cells being arranged in order along a first direction, the connection portion of the cells being bonded to an inner wall of the housing chamber or the adjacent cells; the first direction is the direction of separation of the first side coverage area and the second side coverage area.