Insulating film for an electrode and electrode

Abstract

The utility model relates to battery technology field provides a kind of insulating film and electric core for electric core, the insulating film includes: first film group, including the first membrane body, second membrane body and third membrane body sequentially connected along first direction, and second membrane body is equipped with the avoidance hole and multiple air holes for tab passing through;Second film group, first film group is respectively connected with one second film group in the two sides of first direction, and second film group includes the first folding body, second folding body and third folding body distributed along first direction, first folding body is connected with first membrane body, second folding body is connected with second membrane body, and third folding body is connected with third membrane body;Wherein, the first folding body, second folding body and third folding body of each second film group are adapted to fold relative to first film group and be connected, so that first film group and two second film groups form box body structure with single-sided opening by enclosing. The insulating film can completely wrap one end of the pole group, improve insulation effect.

Description

Technical Field

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

[0002] Lithium-ion batteries, as the primary energy storage device, are finding increasingly wider applications, leading to higher demands for battery safety. A typical battery cell structure includes a casing, electrode arrays, and a cover. The electrode arrays are housed within the casing, and the cover seals them. An insulating film surrounds the electrode arrays to insulate them from the casing. However, the insulating film in existing cell structures often exhibits poor insulation, making short circuits between the electrode arrays and the casing a common problem. Utility Model Content

[0003] This invention provides an insulating film and a battery cell for use in battery cells, in order to solve the problem that the insulating film in the existing battery cell structure has poor insulation effect and is prone to causing short circuits between the electrode group and the casing.

[0004] This utility model provides an insulating film for battery cells, comprising: The first membrane assembly includes a first membrane body, a second membrane body, and a third membrane body connected sequentially along a first direction. The second membrane body is provided with a clearance hole for the electrode tab to pass through and a plurality of vent holes. The second membrane group is connected to the first membrane group on both sides of the first direction. The second membrane group includes a first folding body, a second folding body and a third folding body distributed along the first direction. The first folding body is connected to the first membrane body, the second folding body is connected to the second membrane body, and the third folding body is connected to the third membrane body. In each of the second membrane groups, the first folding body, the second folding body, and the third folding body are adapted to be folded relative to the first membrane group and connected to each other, so that the first membrane group and the two second membrane groups enclose a box structure with a single-sided opening.

[0005] According to the present invention, an insulating film for a battery cell is provided, wherein a plurality of the vent holes are arranged in a matrix.

[0006] According to the present invention, an insulating film for a battery cell is provided, wherein the first folded body, the second folded body, and the third folded body have the same length in a second direction; the second direction is perpendicular to the first direction.

[0007] According to the present invention, an insulating film for a battery cell is provided, wherein the edges of the first folded body and the second folded body that are close to each other are arranged at an angle, and the edges of the second folded body and the third folded body that are close to each other are arranged at an angle.

[0008] According to the present invention, an insulating film for a battery cell is provided, wherein a crease is provided at the connection between the first film body and the second film body, and a crease is provided at the connection between the second film body and the third film body; a crease is provided at the connection between the first folding body and the first film body, a crease is provided at the connection between the second folding body and the second film body, and a crease is provided at the connection between the third folding body and the third film body.

[0009] This utility model also provides a battery cell, comprising: a housing, a first cover plate, an electrode assembly, and any of the above-mentioned insulating films for the battery cell; The housing has a receiving cavity and a first opening communicating with the receiving cavity. The first cover plate is placed over the first opening. The electrode assembly is housed in the receiving cavity. The insulating film is located between the electrode assembly and the housing. The electrode assembly has a first end face and a second end face facing away from each other, and two first side faces and two second side faces connected between the first end face and the second end face. The two first side faces are arranged facing away from each other, and the two second side faces are arranged facing away from each other. The second membrane body is wrapped around the first end face, and the first membrane body and the third membrane body are respectively wrapped around the two first side faces. The two second membrane assemblies are folded relative to the first membrane assembly and are wrapped around the two second side faces one by one. The electrode tabs of the electrode assembly pass through the clearance hole.

[0010] According to the present invention, in a battery cell, the first folding body, the second folding body, and the third folding body of the same second membrane assembly are bonded and fixed together.

[0011] According to the present invention, a battery cell further includes a pressure relief valve, which is disposed on the first cover plate and is disposed opposite to the plurality of vent holes on the second diaphragm.

[0012] According to the present invention, a battery cell is provided on the first cover plate, and the liquid injection hole is arranged opposite to the vent hole on the second membrane.

[0013] According to the present invention, a battery cell further includes: an end plate, which is pressed between the first cover plate and the second membrane, and the end plate is provided with a plurality of through holes, which are arranged one-to-one with a plurality of vent holes on the second membrane; And / or, a second cover plate and a lower plastic, the housing further having a second opening communicating with the receiving cavity, the second cover plate covering the second opening, the lower plastic being located between the second cover plate and the second end face, and the insulating film being connected to the lower plastic.

[0014] This invention provides an insulating film and a battery cell for use in battery cells. By setting a first film group and two second film groups, with one second film group connected to each side of the first film group in a first direction, the first film group can wrap one end face and two opposite sides of the electrode group. The three folding bodies of the second film group fold relative to the first film group to wrap the other two opposite sides of the electrode group, achieving complete wrapping of one end of the electrode group. In conventional technology, the insulating film only covers four sides of the electrode group, which easily creates gaps between the insulating film and the cover plate, causing the electrode group to short-circuit through contact with the casing at these gaps. The insulating film provided in this embodiment can completely wrap one end of the electrode group, preventing short-circuiting between the portion of the electrode group near the first end face and the casing, improving the insulation of the insulating film inside the battery cell, and reducing the risk of short circuits between the electrode group and the casing. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the insulating film structure for battery cells provided by this utility model.

[0017] Figure 2 This is a schematic diagram of the pole group structure.

[0018] Figure 3 This is one of the schematic diagrams of the insulating film provided by this utility model wrapping around the electrode assembly.

[0019] Figure 4 This is a schematic diagram of the assembly of the electrode assembly wrapped with the insulating film provided by this utility model and the first cover plate.

[0020] Figure 5 This is a partial structural diagram of the battery cell provided by this utility model.

[0021] Figure 6 This is the second schematic diagram of the insulating film provided by this utility model wrapping around the electrode assembly.

[0022] Figure 7 This is an assembly diagram of the electrode assembly wrapped with the insulating film provided by this utility model and the second cover plate.

[0023] Figure label: 100. Insulating membrane; 11. First membrane assembly; 111. First membrane body; 112. Second membrane body; 1121. Clearance hole; 1122. Vent hole; 113. Third membrane body; 12. Second membrane assembly; 121. First folded body; 122. Second folded body; 123. Third folded body; 200. Electrode assembly; 21. First side surface; 22. Second side surface; 23. First end face; 24. Second end face; 25. Electrode tab; 300. First cover plate; 31. Liquid injection hole; 32. First electrode post; 33. Pressure relief valve; 400. Second cover plate; 41. Second electrode post; 500. End plate. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0025] In the description of the embodiments of this utility model, it should be noted that, unless otherwise expressly specified and limited, the terms "first," "second," and "third" are numbered to clearly describe product components and do not represent any substantial difference. The terms "installed," "connected," and "joined" should be interpreted broadly; for example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this utility model according to the specific circumstances. Furthermore, "multiple" means two or more.

[0026] The following is combined with Figures 1-7 This invention describes an insulating film for battery cells and a battery cell.

[0027] like Figure 1As shown, the insulating film 100 for a battery cell provided in this embodiment of the present invention includes a first film assembly 11 and two second film assemblies 12. The first film assembly 11 includes a first film body 111, a second film body 112, and a third film body 113 connected sequentially along a first direction. The second film body 112 is provided with a clearance hole 1121 for the tab 25 to pass through and a plurality of vent holes 1122. A second film assembly 12 is connected to each side of the first film assembly 11 in the first direction. The second film assembly 12 includes a first folded body 121, a second folded body 122, and a third folded body 123 distributed along the first direction. The first folded body 121 is connected to the first film body 111, the second folded body 122 is connected to the second film body 112, and the third folded body 123 is connected to the third film body 113. In this configuration, the first folding body 121, the second folding body 122, and the third folding body 123 of each second membrane group 12 are adapted to be folded relative to the first membrane group 11 and connected together, so that the first membrane group 11 and the two second membrane groups 12 enclose a box structure with an opening on one side.

[0028] The insulating film 100 is used in a rectangular battery cell to wrap around the outside of the rectangular electrode assembly 200. During battery cell assembly, the insulating film 100 is a pre-cut sheet of insulating film.

[0029] Understandably, the two second membrane groups 12 are respectively connected to the two sides of the first membrane group 11, the two sides of the first membrane 111 are respectively connected to a first folding body 121, the two sides of the second membrane 112 are respectively connected to a second folding body 122, and the two sides of the third membrane 113 are respectively connected to a third folding body 123.

[0030] like Figure 2 As shown, the electrode assembly 200 has a first end face 23 and a second end face 24 facing away from each other. An electrode tab 25 is connected to the first end face 23, and two first side faces 21 and two second side faces 22 are connected between the first end face 23 and the second end face 24. The two first side faces 21 are arranged facing away from each other, and the two second side faces 22 are arranged facing away from each other.

[0031] See Figure 3When the insulating film 100 is wrapped around the electrode assembly 200, the second film 112 can be wrapped around the first end face 23, and the electrode tab 25 can be passed through the clearance hole 1121. The first film 111 and the third film 113 are both folded 90° relative to the second film 112, so that the first film 111 is wrapped around one first side face 21, and the other second film 112 is wrapped around the other first side face 21. Then, the first folding body 121 of one of the second membrane groups 12 is folded 90° relative to the first membrane 111, the second folding body 122 is folded 90° relative to the second membrane 112, and the third folding body 123 is folded 90° relative to the third membrane 113. The first folding body 121, the second folding body 122, and the third folding body 123 are stacked on one second side 22. Similarly, the first folding body 121, the second folding body 122, and the third folding body 123 of the other second membrane group 12 are stacked on another second side 22.

[0032] It is understood that the insulating film 100 wraps around the first end face 23, the two first side faces 21 and the two second side faces 22 of the electrode assembly 200, and the second end face 24 wraps around the insulating film 100 to form a one-sided opening.

[0033] The battery cell cover typically features a pressure relief valve 33. Multiple vent holes 1122 connect the inside of the electrode assembly 200 to the pressure relief valve 33, allowing gas generated within the electrode assembly 200 to escape through the vent holes 1122 and then through the pressure relief valve 33 out of the housing. The size and number of vent holes 1122 can be configured according to actual needs. Optionally, the multiple vent holes 1122 can be arranged in a matrix, forming a relatively uniform exhaust area on the end face of the electrode assembly 200, which facilitates smooth exhaust from the electrode assembly 200.

[0034] The insulating film 100 for a battery cell provided in this embodiment of the invention comprises a first film group 11 and two second film groups 12. The first film group 11 is connected to a second film group 12 on each side in a first direction. The first film group 11 can wrap one end face and two opposite sides of the electrode group 200, while the three folds of the second film group 12 fold relative to the first film group 11 to wrap the other two opposite sides of the electrode group 200, thus achieving complete wrapping of one end of the electrode group 200. In conventional technology, the insulating film 100 only covers four sides of the electrode group 200, which easily creates gaps between the insulating film 100 and the cover plate, causing the electrode group 200 to short-circuit by contacting the casing through these gaps. The insulating film 100 provided in this embodiment can completely wrap one end of the electrode group 200, preventing short-circuiting between the portion of the electrode group 200 near the first end face 23 and the casing, improving the insulation of the insulating film 100 inside the battery cell, and reducing the risk of short-circuiting between the electrode group 200 and the casing.

[0035] In this embodiment of the invention, the first folding body 121, the second folding body 122, and the third folding body 123 have the same length in the second direction. The second direction is perpendicular to the first direction.

[0036] Understandably, one end of the first folding body 121, the second folding body 122, and the third folding body 123 is connected to the first membrane assembly 11, and the other end extends away from the first membrane assembly 11 along the second direction. The insulating film 100 can be formed by punching. The first folding body 121, the second folding body 122, and the third folding body 123 have the same extension length relative to the first membrane assembly 11, which facilitates the layout of the insulating film 100 during production and reduces waste of film material.

[0037] In this embodiment of the present invention, the edges of the first folding body 121 and the second folding body 122 that are close to each other are set at an angle, and the edges of the second folding body 122 and the third folding body 123 that are close to each other are set at an angle.

[0038] In one specific embodiment, the edges of the first fold 121 near the second fold 122 and the edges of the third fold 123 near the second fold 122 are parallel to a second direction. The edge of the second fold 122 near the first fold 121 is inclined away from the first fold 121, forming an angle between the first fold 121 and the second fold 122. The edge of the second fold 122 near the third fold 123 is inclined away from the third fold 123, forming an angle between the second fold 122 and the third fold 123. This makes the corners of the wrapped electrode assembly 200 relatively flat.

[0039] In this embodiment of the invention, a crease is provided at the connection between the first membrane 111 and the second membrane 112, and a crease is provided at the connection between the second membrane 112 and the third membrane 113. A crease is provided at the connection between the first folding body 121 and the first membrane 111, a crease is provided at the connection between the second folding body 122 and the second membrane 112, and a crease is provided at the connection between the third folding body 123 and the third membrane 113. The insulating film 100 can be permanently creased using mechanical indentation or thermal indentation methods to facilitate the wrapping of the electrode assembly 200 with the insulating film 100.

[0040] This utility model also provides a battery cell, which includes a housing, a first cover plate 300, an electrode assembly 200, and an insulating film 100 for the battery cell as described in any of the above embodiments. The housing has a receiving cavity and a first opening communicating with the receiving cavity. The first cover plate 300 covers the first opening. The electrode assembly 200 is received in the receiving cavity, and the insulating film 100 is located between the electrode assembly 200 and the housing. The electrode assembly 200 has a first end face 23 and a second end face 24 facing away from each other, and two first side faces 21 and two second side faces 22 connecting the first end face 23 and the second end face 24. The two first side faces 21 are arranged facing away from each other, and the two second side faces 22 are arranged facing away from each other. A second membrane 112 wraps around the first end face 23, and a first membrane 111 and a third membrane 113 respectively wrap around the two first side faces 21. The two second membrane assemblies 12 are folded relative to the first membrane assembly 11 and wrapped around the two second side faces 22 one by one. The tabs 25 on the first end face 23 pass through the clearance holes 1121.

[0041] Furthermore, the first folding body 121, the second folding body 122, and the third folding body 123 of the same second membrane assembly 12 are bonded and fixed together. For example, they are bonded and fixed together with tape or glue, so that the folded second membrane assembly 12 forms a whole and wraps around the second side 22.

[0042] When the first folding body 121, the second folding body 122, and the third folding body 123 are folded to the second side 22, the stacking order of the three is not restricted. For example, see Figure 2 The third folding body 123 can be pressed on the outside of the first folding body 121 and the third folding body 123 to make the end face of the wrapped electrode assembly 200 flat.

[0043] The battery cell provided in this embodiment of the present invention also includes a pressure relief valve 33. The pressure relief valve 33 is disposed on the first cover plate 300, and is positioned opposite to a plurality of vent holes 1122 on the second diaphragm 112. The plurality of vent holes 1122 form an exhaust region, the area of ​​which is larger than the area of ​​the pressure relief valve 33. This allows gas within the electrode assembly 200 to be discharged smoothly from the pressure relief valve 33 after being discharged through the plurality of vent holes 1122.

[0044] In some embodiments of this invention, the first cover plate 300 is provided with an injection hole 31, which is arranged opposite to a vent hole 1122 on the second membrane 112. Multiple vent holes 1122 allow gas to escape from the electrode assembly 200 and allow injected electrolyte to enter the electrode assembly 200. Optionally, the injection hole 31 is arranged opposite to one of the vent holes 1122.

[0045] like Figure 4 and Figure 5As shown, the battery cell provided in this embodiment of the present invention also includes an end plate 500, which is pressed between the first cover plate 300 and the second membrane 112. The end plate 500 is provided with a plurality of through holes, which are arranged one-to-one with a plurality of vent holes 1122 on the second membrane 112.

[0046] Specifically, the end plate 500 includes a base plate and multiple side plates connected to the base plate. The base plate is pressed onto the first end face 23 of the electrode assembly 200. The second membrane 112 is located between the base plate and the first end face 23, and multiple through holes are provided on the base plate. The multiple side plates are supported between the base plate and the cover plate. The end plate 500 has through holes opposite to the clearance holes 1121. The electrode tabs 25 are sequentially inserted through the clearance holes 1121 of the insulating membrane 100 and the through holes of the end plate 500, and welded to the first electrode post 32 on the first cover plate 300. By aligning the multiple through holes on the end plate 500 with the multiple vent holes 1122 on the insulating membrane 100, the end plate 500 can be prevented from blocking the vent holes 1122, ensuring smooth venting and liquid injection.

[0047] like Figure 6 and Figure 7 As shown, the battery cell provided in this embodiment of the present invention also includes a second cover plate 400 and a lower plastic layer. The housing also has a second opening communicating with the receiving cavity, and the second cover plate 400 covers the second opening. The lower plastic layer is located between the second cover plate 400 and the second end face 24, and the insulating film 100 is connected to the lower plastic layer.

[0048] The insulating film 100 is open at one end corresponding to the second end face 24 of the electrode assembly 200, and can be welded to the lower plastic along the circumference of the electrode assembly 200 by heat fusion. A tab 25 is also connected to the second end face 24 of the electrode assembly 200, and the tab 25 is welded to the second pole post 41 on the second cover plate 400.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. An insulating film for battery cells, characterized in that, include: The first membrane assembly includes a first membrane body, a second membrane body, and a third membrane body connected sequentially along a first direction. The second membrane body is provided with a clearance hole for the electrode tab to pass through and a plurality of vent holes. The second membrane group is connected to the first membrane group on both sides of the first direction. The second membrane group includes a first folding body, a second folding body and a third folding body distributed along the first direction. The first folding body is connected to the first membrane body, the second folding body is connected to the second membrane body, and the third folding body is connected to the third membrane body. In each of the second membrane groups, the first folding body, the second folding body, and the third folding body are adapted to be folded relative to the first membrane group and connected to each other, so that the first membrane group and the two second membrane groups enclose a box structure with a single-sided opening.

2. The insulating film for battery cells according to claim 1, characterized in that, The multiple vent holes are arranged in a matrix.

3. The insulating film for battery cells according to claim 1, characterized in that, The first folding body, the second folding body, and the third folding body have the same length in the second direction; the second direction is perpendicular to the first direction.

4. The insulating film for battery cells according to claim 1, characterized in that, The edges of the first folding body and the second folding body that are close to each other are set at an angle, and the edges of the second folding body and the third folding body that are close to each other are set at an angle.

5. The insulating film for battery cells according to claim 1, characterized in that, A crease is provided at the connection between the first membrane and the second membrane, and a crease is provided at the connection between the second membrane and the third membrane; a crease is provided at the connection between the first folding body and the first membrane, a crease is provided at the connection between the second folding body and the second membrane, and a crease is provided at the connection between the third folding body and the third membrane.

6. A battery cell, characterized in that, include: The housing, the first cover plate, the electrode assembly, and the insulating film for the battery cell according to any one of claims 1-5; The housing has a receiving cavity and a first opening communicating with the receiving cavity. The first cover plate is placed over the first opening. The electrode assembly is housed in the receiving cavity. The insulating film is located between the electrode assembly and the housing. The electrode assembly has a first end face and a second end face facing away from each other, and two first side faces and two second side faces connected between the first end face and the second end face. The two first side faces are arranged facing away from each other, and the two second side faces are arranged facing away from each other. The second membrane body is wrapped around the first end face, and the first membrane body and the third membrane body are respectively wrapped around the two first side faces. The two second membrane assemblies are folded relative to the first membrane assembly and are wrapped around the two second side faces one by one. The electrode tabs of the electrode assembly pass through the clearance hole.

7. The battery cell according to claim 6, characterized in that, The first folding body, the second folding body, and the third folding body of the same second membrane assembly are bonded and fixed together.

8. The battery cell according to claim 6, characterized in that, Also includes: A pressure relief valve is disposed on the first cover plate, and the pressure relief valve is disposed opposite to the plurality of vent holes on the second diaphragm.

9. The battery cell according to claim 8, characterized in that, The first cover plate is provided with a liquid injection hole, which is arranged opposite to the vent hole on the second membrane.

10. The battery cell according to claim 6, characterized in that, Also includes: An end plate is pressed between the first cover plate and the second membrane. The end plate is provided with a plurality of through holes, which are arranged one-to-one with a plurality of vent holes on the second membrane. And / or, a second cover plate and a lower plastic, the housing further having a second opening communicating with the receiving cavity, the second cover plate covering the second opening, the lower plastic being located between the second cover plate and the second end face, and the insulating film being connected to the lower plastic.

Images