Insulating film and battery cell

Abstract

The utility model discloses an insulating film and a battery cell, the insulating film is used for the battery cell, the insulating film is suitable for wrapping a naked battery cell of the battery cell after being folded, and the insulating film comprises a thin-wall part, the thickness of the thick-wall part is greater than that of the thin-wall part, and the thick-wall part is used for wrapping at least one surface of the naked battery cell. According to the insulating film disclosed by the utility model, the strength of the vulnerable position of the insulating film is effectively enhanced, so that the insulation and isolation effects of the insulating film are further ensured, the risk of internal short circuit of the battery cell caused by powder falling of the naked battery cell and direct contact between the naked battery cell and the shell is effectively prevented, and the safety of the battery cell is improved; and the arrangement of the thin wall part effectively reduces the volume of the naked battery core wrapped by the insulating film, and reduces the space occupied by the insulating film. Meanwhile, in the assembling process of the insulating film and the naked battery cell, only the thick wall part needs to wrap at least one surface of the naked battery cell, and the insulating film is folded to wrap the naked battery cell, so that the assembling process is simple, and the production efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to an insulating film and a battery core. Background Art

[0002] As lithium-ion battery technology becomes increasingly mature, lithium-ion batteries are widely used as power batteries in electric vehicles and energy storage fields, and the requirements for the performance and safety of lithium-ion batteries are increasing. In the prior art, bare cells usually need to be wrapped with a circle of insulating film on their outer surface before being put into the shell. For the vulnerable positions of the insulating film, the strength is usually increased by adding a support connected to the insulating film to ensure the insulation and isolation of the insulating film. However, the process of connecting the support and the insulating film is relatively cumbersome, which increases the difficulty of assembly, and there is a risk of misalignment and loosening of the support, which poses a certain safety risk. Utility Model Content

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model provides an insulating film, which improves the safety of the battery core, simplifies the assembly process, and improves production efficiency.

[0004] The utility model also provides a battery cell, wherein the vehicle comprises the above-mentioned insulating film.

[0005] According to the insulating film of the embodiment of the utility model, the insulating film is used for a battery cell, and the insulating film is suitable for wrapping a bare battery cell of the battery cell after folding. It is characterized in that the insulating film comprises: a thin-walled portion; a thick-walled portion, the thickness of the thick-walled portion is greater than the thickness of the thin-walled portion, and the thick-walled portion is used to wrap at least one surface of the bare battery cell.

[0006] According to the insulating film of the embodiment of the utility model, the insulating film is suitable for wrapping the bare battery cell of the battery after folding. The thickness of the thick-walled portion is greater than the thickness of the thin-walled portion. The thick-walled portion is used to wrap at least one surface of the bare battery cell, thereby effectively strengthening the strength of the vulnerable position of the insulating film, thereby ensuring the insulation and isolation function of the insulating film, effectively preventing the bare battery cell from losing powder and the risk of the bare battery cell directly contacting the outer shell to cause an internal short circuit in the battery cell, and improving the safety of the battery cell. The provision of the thin-walled portion effectively reduces the volume of the bare battery cell after being wrapped by the insulating film, and reduces the space occupied by the insulating film. At the same time, during the assembly process of the insulating film and the bare battery cell, only the thick-walled portion is required to wrap at least one surface of the bare battery cell, and the insulating film is folded to wrap the bare battery cell, so as to simplify the assembly process and improve production efficiency.

[0007] In some embodiments of the present invention, the thickness of the thin-walled portion is L, and the thickness of the thick-walled portion is H, wherein 0.2 mm ≥ L ≥ 0.05 mm, and H ≥ L + 0.2 mm.

[0008] In some embodiments of the present invention, the insulating film is an integral piece.

[0009] The battery cell according to the embodiment of the utility model includes: a shell; a bare battery cell, wherein the bare battery cell is arranged in the shell; the above-mentioned insulating film, wherein the insulating film is arranged in the shell and wrapped around the bare battery cell; and a blue film, wherein the blue film is suitable for wrapping the shell.

[0010] According to the battery cell of the embodiment of the utility model, an insulating film is provided, and the thickness of the thick-walled portion of the insulating film is greater than the thickness of the thin-walled portion. The thick-walled portion is used to wrap at least one surface of the bare battery cell, thereby effectively strengthening the strength of the vulnerable position of the insulating film, thereby ensuring the insulation and isolation function of the insulating film, effectively preventing the bare battery cell from losing powder and the risk of the bare battery cell directly contacting the outer shell and causing an internal short circuit in the battery cell, thereby improving the safety of the battery cell, and the provision of the thin-walled portion effectively reduces the volume of the bare battery cell after being wrapped by the insulating film, and reduces the space occupied by the insulating film in the outer shell. At the same time, during the assembly process of the battery cell, only the thick-walled portion is required to wrap at least one surface of the bare battery cell, and the insulating film is folded and wrapped around the bare battery cell, thereby simplifying the assembly process and improving production efficiency.

[0011] In some embodiments of the present invention, the thick-walled portion wraps a surface of the bare battery core, the width of the thick-walled portion is A, the width of the outer surface of the shell opposite to the thick-walled portion is B, the thickness of the shell on both sides of the width direction of the thick-walled portion is C, the thickness of the blue film is D, and the gap between the two surfaces of the bare battery core on both sides of the width direction of the thick-walled portion and the shell is E, wherein A=B-2*(C+D+E); and / or, the length of the thick-walled portion is F, the total length of the insulating film along the length direction of the thick-walled portion is G, the width of the outer surface of the shell opposite to the thick-walled portion is B, and the thickness of the blue film is D, wherein G-(B+D) / 4≤F≤G.

[0012] In some embodiments of the utility model, the shell includes a shell and a top cover, one side of the shell is opened to form an open opening, the top cover is arranged at the open opening to seal the open opening, the insulating film covers the remaining surface of the bare battery cell except the surface opposite to the top cover, and the thick wall portion covers the surface of the bare battery cell facing away from the top cover.

[0013] In some embodiments of the utility model, the thin-walled portion includes two main bodies and two folded portions, the two main bodies are respectively connected to the two ends of the thick-walled portion in the width direction, and are used to wrap the two opposite surfaces of the bare battery cell along the width direction of the top cover, the two folded portions are respectively connected to the two ends of the thick-walled portion in the length direction, and parts of the two folded portions and the two main bodies are used to wrap the two opposite surfaces of the bare battery cell along the length direction of the top cover.

[0014] In some embodiments of the utility model, the shell includes a shell and a top cover, both ends of the shell in the length direction are open to form an open opening, the top covers are two and respectively block the two open openings, the insulating film covers the remaining surfaces of the bare battery cell except the surface opposite to the top cover, and the thick wall portion covers a surface of the bare battery cell in the width direction.

[0015] In some embodiments of the utility model, the thin-walled portion includes a first section, a second section, a third section and a fourth section connected in sequence, wherein the first section is connected to the thick-walled portion, the fourth section is stacked and connected to the thick-walled portion, the second section and the thick-walled portion wrap two opposite surfaces of the bare battery cell in the width direction, and the first section and the third section include two opposite surfaces of the bare battery cell in the thickness direction.

[0016] In some embodiments of the present invention, the width of the thick-walled portion is H, the width of the second section is I, and the thickness of the thin-walled portion is L, wherein I≤H-2L.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0019] Figure 1 is a diagram of the expanded structure of the insulating film according to the first embodiment of the utility model;

[0020] Figure 2 It is a schematic diagram of the structure of the battery cell according to the first embodiment of the utility model, wherein the bare battery cell is not wrapped by the insulating film, and the shell and the blue film are not shown;

[0021] Figure 3 It is a schematic diagram of the structure of the battery cell according to the first embodiment of the utility model, wherein the bare battery cell is wrapped with an insulating film, and the shell and the blue film are not shown;

[0022] Figure 4 is a diagram of the expanded structure of an insulating film according to a second embodiment of the utility model;

[0023] Figure 5 is a diagram of the expanded structure of an insulating film according to a third embodiment of the utility model;

[0024] Figure 6 is a structural diagram of an insulating film according to a third embodiment of the utility model;

[0025] Figure 7 yes Figure 6 A cross-sectional view of

[0026] Figure 8 yes Figure 7 Enlarged view of point L in the middle.

[0027] Reference numerals:

[0028] 1000, battery cell;

[0029] 100. Insulating film;

[0030] 1. thin-walled portion; 11. main body; 12. folded portion; 13. first section; 14. second section; 15. third section; 16. fourth section; 17. open mouth;

[0031] 2. Thick wall part;

[0032] 200, top cover;

[0033] 300. Bare battery cells. DETAILED DESCRIPTION

[0034] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0035] In the description of the present utility model, it is necessary to understand that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, unless otherwise specified, "multiple" means two or more.

[0036] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] The insulating film 100 according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0038] like Figure 1 , Figure 4 and Figure 5 As shown, the insulating film 100 according to the embodiment of the utility model is used for the battery cell 1000, and the insulating film 100 is suitable for wrapping the bare battery cell 300 of the battery cell 1000 after folding, and the insulating film 100 includes a thin-walled portion 1 and a thick-walled portion 2. The thickness of the thick-walled portion 2 is greater than that of the thin-walled portion 1, and the thick-walled portion 2 is used to wrap at least one surface of the bare battery cell 300.

[0039] Therefore, after the folded insulating film 100 wraps the bare cell 300, the bare cell 300 is placed in the outer shell of the cell 1000, so that the bare cell 300 is put into the shell. By setting the thick wall part 2 at the vulnerable position of the insulating film 100 and setting the thin wall part 1 in other areas, the strength of the vulnerable position of the insulating film 100 is effectively enhanced, thereby ensuring the insulation and isolation function of the insulating film 100, effectively preventing the bare cell 300 from falling off and the risk of the bare cell 300 directly contacting the outer shell and causing an internal short circuit in the cell 100, thereby improving the safety of the cell 1000, and the setting of the thin wall part 1 effectively reduces the volume of the bare cell 300 wrapped by the insulating film 100, and reduces the space occupied by the insulating film 100.

[0040] At the same time, the thick wall portion 2 is used to wrap at least one surface of the bare cell 300, and the strength of the thick wall portion 2 is effectively guaranteed after the insulating film 100 wraps the bare cell 300, which effectively reduces the risk factor of damage to the thick wall portion 2 and improves safety. Figure 1 As shown, when the insulating film 100 of the present application is applied to a square battery, since the bottom of the battery cell 1000 is more susceptible to greater impact due to factors such as vehicle bumps, the thick wall portion 2 is used to wrap the bottom wall of the bare battery cell 300, effectively preventing the thick wall portion 2 from being damaged and causing the bare battery cell 300 to directly contact the shell, thereby improving the reliability of the square battery. Or, as Figure 5As shown, when the insulating film 100 of the present application is applied to a blade battery, since the weld position of the outer shell of the blade battery is easily damaged to the insulating film 100 during the welding connection process, the thick-walled portion 2 is used to wrap the wall surface of the bare battery cell 300 at the relative weld position, thereby effectively preventing the thick-walled portion 2 from being damaged and causing direct contact between the bare battery cell 300 and the outer shell, thereby improving the reliability of the blade battery.

[0041] Compared with the prior art in which a support piece is provided at a vulnerable position of the insulating film 100 to ensure the structural strength of the vulnerable position, the insulating film 100 of the present application is provided by combining a thin-walled portion 1 and a thick-walled portion 2 so that the thick-walled portion 2 can effectively prevent the insulating film 100 from being damaged at the vulnerable position. In addition, during the assembly process of the battery cell 1000 of the present application, it is only necessary to fold the insulating film 100 and wrap the bare battery cell 300, which simplifies the assembly process and improves production efficiency.

[0042] According to the insulating film 100 of the embodiment of the utility model, the insulating film 100 is suitable for wrapping the bare cell 300 of the battery 1000 after folding. The thickness of the thick-walled portion 2 is greater than the thickness of the thin-walled portion 1, and the thick-walled portion 2 is used to wrap at least one surface of the bare cell 300, thereby effectively strengthening the strength of the vulnerable position of the insulating film 100, thereby ensuring the insulation and isolation function of the insulating film 100, effectively preventing the bare cell 300 from falling off and the risk of the bare cell 300 directly contacting the shell to cause an internal short circuit in the battery 1000, thereby improving the safety of the battery 1000, and the setting of the thin-walled portion 1 effectively reduces the volume of the bare cell 300 after being wrapped by the insulating film 100, and reduces the space occupied by the insulating film 100. At the same time, during the assembly process of the insulating film 100 and the bare cell 300, only the thick-walled portion 2 is required to wrap at least one surface of the bare cell 300, and the insulating film 100 is folded and wrapped around the bare cell 300, so as to simplify the assembly process and improve production efficiency.

[0043] In some embodiments of the present invention, the thickness of the thin-walled portion 1 is L, and the thickness of the thick-walled portion 2 is H, wherein 0.2 mm ≥ L ≥ 0.05 mm, and H ≥ L + 0.2 mm. It can be understood that the thickness of the thin-walled portion 1 is 0.05 mm, 0.1 mm, 0.15 mm, or 0.2 mm, and the thickness of the thin-walled portion 1 is 0.2 mm greater than the thickness of the thin-walled portion 1. Thus, by such a configuration, the thickness of the thick-walled portion 2 is greater than the thickness of the thin-walled portion 1, effectively improving the structural strength of the thick-walled portion 2, and the insulating film 100 configured in this way is easier to position and automate.

[0044] In some embodiments of the present invention, the insulating film 100 is an integral part. Thus, by configuring the thick-walled portion 2 and the thin-walled portion 1 as an integral part, the assembly difficulty is reduced and the assembly efficiency is improved during the process of wrapping the bare battery cell 300 after the insulating film 100 is folded. At the same time, the insulating film 100 is an integral part, which improves the overall structural strength of the insulating film 100 and further improves the reliability.

[0045] The battery cell 1000 according to the embodiment of the present invention is described below.

[0046] According to the battery cell 1000 of the embodiment of the utility model, Figure 1-Figure 6 As shown, the battery cell 1000 includes a shell, a bare battery cell 300, an insulating film 100 and a blue film. The bare battery cell 300 is arranged in the shell, the insulating film 100 is arranged in the shell and wrapped outside the bare battery cell 300, and the blue film is suitable for wrapping the shell. It can be understood that during the assembly process of the battery cell 1000, the insulating film 100 is first folded and wrapped around the bare battery cell 300, and then the bare battery cell 300 is placed in the shell, and finally the blue film is wrapped around the shell. The thickness of the thick-walled portion 2 of the insulating film 100 is greater than the thickness of the thin-walled portion 1, and the thick-walled portion 2 is used to wrap at least one surface of the bare cell 300, thereby effectively strengthening the strength of the vulnerable position of the insulating film 100, thereby ensuring the insulation and isolation function of the insulating film 100, effectively preventing the bare cell 300 from falling off and the risk of the bare cell 300 directly contacting the shell and causing an internal short circuit in the cell 1000, thereby improving the safety of the cell 1000. The setting of the thin-walled portion 1 effectively reduces the volume of the bare cell 300 after being wrapped by the insulating film 100, and reduces the space occupied by the insulating film 100 in the shell. At the same time, during the assembly process of the cell 1000, only the thick-walled portion 2 is required to wrap at least one surface of the bare cell 300, and the insulating film 100 is folded and wrapped around the bare cell 300, so as to simplify the assembly process and improve production efficiency.

[0047] According to the battery cell 1000 of the embodiment of the utility model, an insulating film 100 is provided, and the thickness of the thick wall portion 2 of the insulating film 100 is greater than the thickness of the thin wall portion 1, and the thick wall portion 2 is used to wrap at least one surface of the bare battery cell 300, thereby effectively strengthening the strength of the vulnerable position of the insulating film 100, thereby ensuring the insulation and isolation function of the insulating film 100, effectively preventing the bare battery cell 300 from falling off and the risk of the bare battery cell 300 directly contacting the shell to cause an internal short circuit in the battery cell 1000, thereby improving the safety of the battery cell 1000, and the provision of the thin wall portion 1 effectively reduces the volume of the bare battery cell 300 after being wrapped by the insulating film 100, and reduces the space occupied by the insulating film 100 in the shell. At the same time, during the assembly process of the battery cell 1000, only the thick wall portion 2 is required to wrap at least one surface of the bare battery cell 300, and the insulating film 100 is folded and wrapped around the bare battery cell 300, so that the assembly process is simple and the production efficiency is improved.

[0048] In some embodiments of the present invention, Figure 1 and Figure 5 As shown, the thick-walled portion 2 wraps one surface of the bare cell 300, the width of the thick-walled portion 2 is A, the width of the outer surface of the shell opposite to the thick-walled portion 2 is B, the thickness of the shell on both sides of the width direction of the thick-walled portion 2 is C, the thickness of the blue film is D, and the gap between the two surfaces of the bare cell 300 on both sides of the width direction of the thick-walled portion 2 and the shell is E, where A=B-2*(C+D+E). Therefore, by limiting the size of the width of the thick-walled portion 2 through the above formula, while ensuring that the thick-walled portion 2 wraps one surface of the bare cell 300, the bare cell 300 wrapped by the insulating film 100 can be placed in the shell, ensuring that the assembly process of the cell 1000 is reliable.

[0049] In some embodiments of the present invention, Figure 1 and Figure 5 As shown, the thick wall portion 2 wraps one surface of the bare cell 300, the length of the thick wall portion 2 is F, the total length of the insulating film 100 along the length direction of the thick wall portion 2 is G, the width of the outer surface of the shell opposite to the thick wall portion 2 is B, and the thickness of the blue film is D, wherein G-(B+D) / 4≤F≤G. Therefore, by limiting the length of the thick wall portion 2 by the above formula, while ensuring that the thick wall portion 2 wraps one surface of the bare cell 300, the bare cell 300 wrapped by the insulating film 100 can be placed in the shell, ensuring that the assembly process of the cell 1000 is reliable.

[0050] In some embodiments of the present invention, Figure 1-Figure 3 As shown, the outer shell includes a shell and a top cover 200, one side of the shell is opened to form an open opening 17, the top cover 200 is arranged at the open opening 17 to seal the open opening 17, the insulating film 100 covers the remaining surface of the bare battery cell 300 except the surface opposite to the top cover 200, and the thick wall portion 2 covers the surface of the bare battery cell 300 away from the top cover 200.

[0051] It is understandable that if Figure 1-Figure 3 The battery cell 1000 shown is a square battery cell 1000, and one side of the shell is opened to form an open opening 17, so that the bare battery cell 300 wrapped by the insulating film 100 can be placed in the shell through the open opening 17, and the top cover 200 is arranged at the open opening 17 to block the open opening 17 to ensure the sealing of the shell. At the same time, the insulating film 100 covers the remaining surfaces of the bare battery cell 300 except the surface opposite to the top cover 200, effectively preventing the bare battery cell 300 from falling off and the risk of the bare battery cell 300 directly contacting the shell and causing an internal short circuit in the battery cell 1000. In addition, the top cover 200 is located at the top of the battery cell 1000. Since the bottom of the battery cell 1000 is more susceptible to greater impact due to factors such as vehicle bumps, the thick wall portion 2 is used to wrap the bottom wall of the bare battery cell 300, effectively preventing the thick wall portion 2 from being damaged and causing the bare battery cell 300 to directly contact the shell, thereby improving reliability.

[0052] In some embodiments of the present invention, Figure 1 As shown, the thin-walled portion 1 includes two main bodies 11 and two folded portions 12. The two main bodies 11 are respectively connected to the two ends of the thick-walled portion 2 in the width direction, and are used to wrap the two opposite surfaces of the bare cell 300 along the width direction of the top cover 200. The two folded portions 12 are respectively connected to the two ends of the thick-walled portion 2 in the length direction. The two folded portions 12 and the two main bodies 11 are used to wrap the two opposite surfaces of the bare cell 300 along the length direction of the top cover 200. Thus, through such an arrangement, the insulating film 100 wraps the remaining surfaces of the bare cell 300 except the surface opposite to the top cover 200, and the thick-walled portion 2 wraps the surface of the bare cell 300 away from the top cover 200.

[0053] In some embodiments of the present invention, Figure 4 As shown, the insulating film 100 is an integral part, the thickness of the two folded parts 12 is the same as the thickness of the thick-walled part 2, the length of the two folded parts 12 is J, the length of the thick-walled part 2 is F, the total length of the insulating film 100 along the length direction of the thick-walled part 2 is G, the width of the outer surface of the shell opposite to the thick-walled part 2 is B, the thickness of the blue film is D, and G-(B+D) / 4≤F+2J≤G. Therefore, the length of the two folded parts 12 and the thick-walled part 2 as a whole is limited by the formula G-(B+D) / 4≤F+2J≤G, so that the thick-walled part 2 covers the surface of the bare cell 300 away from the top cover 200, and after the two folded parts 12 and the two main body parts 11 are used to wrap the two opposite surfaces of the bare cell 300 along the length direction of the top cover 200, each folded part 12 and the two main body parts 11 have an overlapping area, which is convenient for their connection and reduces the difficulty of assembly.

[0054] In some embodiments of the present invention, Figure 5-Figure 8 As shown, the outer shell includes a shell and a top cover 200, both ends of the shell in the length direction are open to form an open opening 17, there are two top covers 200 and they respectively block the two open openings 17, the insulating film 100 covers the remaining surfaces of the bare cell 300 except the surface opposite to the top cover 200, and the thick wall portion 2 covers a surface of the bare cell 300 in the width direction.

[0055] It is understandable that if Figure 5-Figure 8The battery cell 1000 shown is a blade battery cell 1000, and both ends of the shell in the length direction are open to form an open opening 17, so that the bare battery cell 300 wrapped by the insulating film 100 is placed in the shell through one of the open openings 17, and the top cover 200 is used to form two and respectively block the two open openings 17 to ensure the sealing of the shell. At the same time, the insulating film 100 covers the remaining surfaces of the bare battery cell 300 except the surface opposite to the top cover 200, effectively preventing the bare battery cell 300 from falling off and the risk of the bare battery cell 300 directly contacting the shell and causing an internal short circuit in the battery cell 1000. In addition, since the weld position of the outer shell of the blade battery is easy to cause damage to the insulating film 100 during the welding connection process, the thick wall portion 2 is used to wrap a surface in the width direction of the bare battery cell 300 as the surface at the weld position, which effectively prevents the thick wall portion 2 from being damaged and causing the bare battery cell 300 to directly contact the shell, thereby improving reliability.

[0056] In some embodiments of the present invention, Figure 5 As shown, the thin-walled portion 1 includes a first section 13, a second section 14, a third section 15 and a fourth section 16 connected in sequence, wherein the first section 13 is connected to the thick-walled portion 2, the fourth section 16 is stacked and connected to the thick-walled portion 2, the second section 14 and the thick-walled portion 2 wrap the two opposite surfaces of the bare cell 300 in the width direction, and the first section 13 and the third section 15 include the two opposite surfaces of the bare cell 300 in the thickness direction. Thus, through such an arrangement, the insulating film 100 covers the remaining surfaces of the bare cell 300 except the surface opposite to the top cover 200, and the thick-walled portion 2 covers one surface of the bare cell 300 in the width direction. At the same time, by stacking and connecting the fourth section 16 and the thick-walled portion 2, the structural strength of the thick-walled portion 2 is further improved, effectively preventing the thick-walled portion 2 from being damaged and causing the bare cell 300 to directly contact the shell, thereby improving reliability.

[0057] In some embodiments of the present invention, Figure 5 As shown, the width of the thick-walled portion 2 is H, the width of the second section 14 is I, and the thickness of the thin-walled portion 1 is L, where I≤H-2L. It can be understood that since the second section 14 and the thick-walled portion 2 wrap the two opposite surfaces of the bare cell 300 in the width direction, the width of the thick-walled portion 2 is limited by the above formula to ensure that the thick-walled portion 2 wraps the opposite surface of the bare cell 300 wrapped by the second section 14, thereby improving reliability.

[0058] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0059] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. An insulating film for a battery cell, wherein the insulating film is suitable for wrapping a bare battery cell of the battery cell after folding, characterized in that: The insulating film comprises: Thin wall part; A thick-walled portion, the thickness of which is greater than the thickness of the thin-walled portion, and the thick-walled portion is used to wrap at least one surface of the bare battery core.

2. The insulating film according to claim 1, wherein The thickness of the thin-walled portion is L, and the thickness of the thick-walled portion is H, wherein 0.2 mm ≥ L ≥ 0.05 mm, and H ≥ L + 0.2 mm.

3. The insulating film according to claim 1, wherein The insulating film is an integral piece.

4. A battery cell, characterized in that: include: shell; A bare battery cell, wherein the bare battery cell is disposed in the housing; The insulating film according to any one of claims 1 to 3, wherein the insulating film is arranged in the housing and wrapped outside the bare cell; A blue film is suitable for wrapping the shell.

5. The battery cell according to claim 4, characterized in that: The thick wall portion wraps one surface of the bare battery core, The width of the thick wall portion is A, the width of the outer surface of the shell opposite to the thick wall portion is B, the thickness of the shell on both sides of the width direction of the thick wall portion is C, the thickness of the blue film is D, and the gap between the two surfaces of the bare cell on both sides of the width direction of the thick wall portion and the shell is E, wherein A=B-2*(C+D+E); And / or, the length of the thick-walled portion is F, the total length of the insulating film along the length direction of the thick-walled portion is G, the width of the outer surface of the shell opposite to the thick-walled portion is B, and the thickness of the blue film is D, wherein G-(B+D) / 4≤F≤G.

6. The battery cell according to claim 4, characterized in that: The shell includes a shell and a top cover, one side of the shell is opened to form an open opening, the top cover is arranged at the open opening to seal the open opening, the insulating film covers the remaining surface of the bare battery cell except the surface opposite to the top cover, and the thick wall portion covers the surface of the bare battery cell away from the top cover.

7. The battery cell according to claim 6, characterized in that: The thin-walled portion includes two main bodies and two folded portions, the two main bodies are respectively connected to the two ends of the thick-walled portion in the width direction, and are used to wrap the two opposite surfaces of the bare battery cell along the width direction of the top cover, the two folded portions are respectively connected to the two ends of the thick-walled portion in the length direction, and the two folded portions and parts of the two main bodies are used to wrap the two opposite surfaces of the bare battery cell along the length direction of the top cover.

8. The battery cell according to claim 4, characterized in that: The shell includes a shell and a top cover, both ends of the shell in the length direction are open to form an open opening, there are two top covers and they respectively block the two open openings, the insulating film covers the remaining surfaces of the bare battery cell except the surface opposite to the top cover, and the thick wall portion covers a surface of the bare battery cell in the width direction.

9. The battery cell according to claim 8, characterized in that: The thin-walled portion includes a first section, a second section, a third section and a fourth section connected in sequence, wherein the first section is connected to the thick-walled portion, the fourth section is stacked and connected to the thick-walled portion, the second section and the thick-walled portion wrap two opposite surfaces of the bare cell in the width direction, and the first section and the third section include two opposite surfaces of the bare cell in the thickness direction.

10. The battery cell according to claim 9, characterized in that: The width of the thick-walled portion is H, the width of the second section is I, and the thickness of the thin-walled portion is L, wherein I≤H-2L.

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