Lithium battery insulating film and lithium battery

Abstract

The utility model provides a lithium battery insulating film and a lithium battery, the lithium battery insulating film is used for coating a battery cell group, the lithium battery insulating film comprises an insulating layer, the insulating layer comprises a main coating area, and a bottom coating area, a top coating area, a first side surface coating area and a second side surface coating area which are arranged on the peripheral side of the main coating area in a surrounding manner, the top edge of the main coating area is connected with the long edge of the top coating area, the bottom edge of the main coating area is connected with the long edge of the bottom coating area, the two side edges of the main coating area are connected with the first side surface coating area and the second side surface coating area respectively, and the width of the bottom coating area is greater than or equal to the total thickness of cells of a coated cell group; and the adhesive layer is arranged on one side, in contact with the battery cell group, of the insulating layer. The insulating film provided by the utility model can cancel a traditional insulating film hot melting process, cancel a bottom supporting sheet at the bottom of the battery cell, cancel a traditional bottom supporting sheet hot melting process, and improve the production efficiency.

Description

Technical Field

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

[0002] During the manufacturing process of square lithium batteries, after the battery cells are manufactured, they need to be placed in a hard square aluminum shell to complete the assembly. Since the aluminum shell is relatively hard, there is a risk of scratching the battery cells. Therefore, before the battery cells are placed in the aluminum shell, they need to be wrapped with a soft and flexible insulating film to prevent the aluminum shell from damaging the battery cells. In the prior art, an insulating film is usually used to wrap a single battery cell, and the insulating film is wrapped on the surface of the battery cell by hot melting. In addition, there is a bottom support sheet between the bottom of the outer shell and the winding core of the existing battery. The insulating film and the bottom support sheet are generally fixed together by hot melting. However, the hot melting process is complicated, and the hot melting process is prone to wire drawing, which causes the wire drawing to be clamped into the weld when welding the top cover, causing welding explosion points and affecting the quality of the battery. Utility Model Content

[0003] In order to overcome the defects in the prior art, the embodiment of the present invention provides a lithium battery insulating film and a lithium battery, which can eliminate the traditional insulating film hot-melt process, eliminate the bottom support sheet at the bottom of the battery cell, omit the traditional bottom support sheet hot-melt process, and improve production efficiency.

[0004] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0005] The first aspect of the utility model discloses a lithium battery insulating film for coating a battery cell group, comprising:

[0006] An insulating layer, the insulating layer comprising a main covering region and a bottom covering region, a top covering region, a first side covering region, and a second side covering region arranged around the main covering region, wherein the top edge of the main covering region is connected to the long edge of the top covering region, the bottom edge is connected to the long edge of the bottom covering region, the two side edges are respectively connected to the first side covering region and the second side covering region, and the width of the bottom covering region is greater than or equal to the total thickness of the cells of the covered battery cell group;

[0007] An adhesive layer is provided on a side of the insulating layer that contacts the battery cell group.

[0008] When the insulating film provided by the above technical solution is used to wrap the battery cell group, one insulating film half-wraps one battery cell group, and two identical insulating films jointly wrap the two battery cell groups. The width of the bottom wrapping area is greater than or equal to the total thickness of the batteries in the two wrapped battery cell groups. When wrapping, the bottom of the battery cell is jointly wrapped by the double-layer bottom wrapping area. There is no need to set a bottom support sheet at the bottom of the battery cell group, and there is no need for the traditional bottom support sheet and insulating film hot melting process, which can improve production efficiency and avoid the wire drawing at the bottom of the battery cell causing the explosion point. In addition, setting an adhesive layer on the insulating layer can simplify the process of wrapping the battery cell with the insulating film and avoid the wire drawing after hot melting causing the explosion point.

[0009] Furthermore, the thickness of the bottom coating area is 0.12 to 0.2 mm. During coating, the bottom of the battery cell group is coated with a double-layer bottom coating area. The thickness of the double-layer bottom coating area is consistent with the total thickness of the traditional insulation film and bottom support sheet combination. The bottom support sheet set at the bottom of the battery cell can be eliminated, simplifying the battery cell production process.

[0010] Furthermore, both the bottom and top encapsulation regions are provided with through-holes. When the bottom encapsulation region is rotated 180° along its plane, at least some of the through-holes overlap with at least some of the through-holes in the unrotated state. The through-holes are provided for the flow of electrolyte. When encapsulating the battery cell assembly, the bottom of the battery cell assembly is co-encapsulated by the bottom encapsulation regions of the two insulating films, and the two bottom encapsulation regions completely overlap. At least some of the through-holes need to be aligned to facilitate the flow of electrolyte.

[0011] Furthermore, at least one through-hole is provided in each of the bottom and top cladding regions. When two or more through-holes are provided, the through-holes are evenly spaced and distributed across the bottom and top cladding regions. Furthermore, the through-holes have a diameter of 1 to 3 mm. The flow holes in the top and bottom cladding regions facilitate electrolyte infiltration. Providing multiple evenly distributed through-holes can enhance the infiltration effect, while ensuring that the through-holes do not affect the cladding effect or the strength of the insulating film.

[0012] Furthermore, the adhesive layer is provided on the bottom coating area, the top coating area, the first side coating area and the second side coating area. The adhesive layer is only required to fix the insulating film on the battery cell, and the main coating area does not need to be provided with adhesive to save costs.

[0013] Furthermore, the widths of the top covering region, the first side covering region, and the second side covering region are each set to be 2-5 mm greater than the thickness of the cell group to be covered. During covering, one insulating film half-covers one cell group, and the top covering region, the first side covering region, and the second side covering region are larger than the thickness of the half-covered cell group to improve the covering effect and ensure complete covering.

[0014] Furthermore, the adhesive is a double-sided adhesive, one side of which is bonded to the inner surface of the insulating layer, and the other side of which is bonded to the outer surface of the battery cell group.

[0015] Furthermore, an opening is provided on the top covering area, and the opening is used for passing the tab.

[0016] Furthermore, the insulating film is a polyester film.

[0017] A second aspect of the present invention discloses a lithium battery, comprising a battery cell and an insulating film as described in any one of the first aspects disclosed and coated on the outer surface of the battery cell.

[0018] Due to the application of the above technical solution, the utility model has the following advantages compared with the prior art:

[0019] 1. In the present application, the bottom covering area of ​​the two insulating films is used to cover the bottom of the battery cell group, and the width of the bottom covering area is set to be greater than or equal to the total thickness of the battery cells in the covered battery cell group. There is no need to set a bottom support sheet at the bottom of the battery cell, which can reduce the traditional bottom support sheet and insulating film hot melting process and improve production efficiency.

[0020] 2. This application provides a top covering area on the top of the battery cell to fully cover the top of the battery cell. The tabs only pass through the openings in the top covering area of ​​the battery cell. This can prevent the tabs from being inserted upside down into the battery cell after the tabs are bent and covered, causing a short circuit in the battery cell.

[0021] 3. The present application fixes the insulating film and the battery cell by setting adhesive, and there is no need to connect the insulating film and the battery cell by hot melting, which avoids poor explosion points, reduces the hot melting process, and improves production efficiency. In addition, the adhesive is set on the bottom covering area, the top covering area, the first side covering area and the second side covering area. There is no need to set adhesive on the entire insulating film, which can achieve fixation and reduce costs.

[0022] In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 This is a schematic diagram of the expanded structure of the insulating film provided by an embodiment of the present utility model;

[0025] Figure 2 This is a three-dimensional diagram of a battery cell wrapped with an insulating film provided by an embodiment of the present invention.

[0026] The figure marks in the above drawings are: 1. main coating area; 2. top coating area; 3. bottom coating area; 4. first side coating area; 5. second side coating area; 6. through hole; 7. opening; 8. tab; 9. overlapping area; 10. first insulating layer; 11. second insulating layer. DETAILED DESCRIPTION

[0027] The following will be combined with the accompanying drawings of the embodiments of the present invention to clearly and completely describe the technical solutions of the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. In addition, the drawings of the present invention are only for simple schematic illustration and are not depicted according to actual size. Please note in advance.

[0028] In the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", "forward", "back", "between", "close to", "far away" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention. It should also be noted that, unless otherwise clearly specified and limited, the terms "installation" 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 direct connection or an indirect connection. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0029] It should be understood that although terms such as "first," "second," and "third" may be used herein to describe various components or signals, these components or signals should not be limited by these terms. These terms are primarily used to distinguish one component from another, or one signal from another. In addition, the term "or" as used herein may include any one or more combinations of the associated listed items, as appropriate.

[0030] Reference Figure 1An embodiment of the utility model provides an insulating film, which is used to wrap a battery cell group, including: an insulating layer, wherein the insulating layer includes a main coating area 1 and a bottom coating area 2, a top coating area 3, a first side coating area 4 and a second side coating area 5 arranged around the main coating area 1, wherein the top edge of the main coating area 1 is connected to the long edge of the top coating area 2, the bottom edge is connected to the long edge of the bottom coating area 3, and the two side edges are respectively connected to the first side coating area 4 and the second side coating area 5, and the width of the bottom coating area 3 is greater than or equal to the total thickness of the batteries in the coated battery cell group.

[0031] The insulating film provided in the embodiment of the present application can be made of a variety of materials. In a possible embodiment, the insulating film can be a polyester film.

[0032] It should be noted that the insulating film provided in the embodiment of the present application is used to wrap the battery cell group, and the battery cell group may include multiple battery cells of different numbers. In the embodiment of the present application, wrapping two battery cell groups is used as an example for explanation. The two wrapped battery cell groups are exactly the same, and any battery cell group can include several battery cells of different numbers.

[0033] During wrapping, one insulating film half-wraps one battery cell group, and two identical insulating films jointly wrap two battery cell groups, wherein the bottom wrapping area of ​​one insulating film completely covers the bottom wrapping area of ​​the other insulating film, and the top wrapping area, the first side wrapping area and the second side wrapping area of ​​one insulating film at least partially cover the top wrapping area, the first side wrapping area and the second side wrapping area of ​​the other insulating film.

[0034] like Figure 1 As shown, a main covering area 1 is provided on an insulating layer, and the bottom covering area 2, the top covering area 3, the first side covering area 4 and the second side covering area 5 are arranged on the peripheral side of the main covering area 1, wherein the top edge of the main covering area 1 is connected to the long side of the top covering area 2, the bottom edge of the main covering area 1 is connected to the long side of the bottom covering area 3, and the two side edges are respectively connected to the first side covering area 4 and the second side covering area 5.

[0035] It should be noted that the top covering area 2 of the insulating layer is the covering area on the side where the tabs are set in the battery cell group, the bottom covering area 3 is the covering area on the side opposite to the side where the tabs are set in the battery cell group, the main covering area 1 is the covering area arranged between the top covering area 2 and the bottom covering area 3, and the first side covering area 4 and the second side covering area 5 are the covering areas arranged on the other two sides of the main covering area 1.

[0036] It should be further explained that the edge connecting the top covering area 2 and the main covering area 1 is set as the long side of the top covering area 2 and the top side of the main covering area 1, the edge connecting the bottom covering area 3 and the main covering area 1 is set as the long side of the bottom covering area 3 and the bottom side of the main covering area 1, and the remaining two edges of the main covering area 1 are side edges. During wrapping, the top edge connecting the top covering area 2 and the main covering area 1, the bottom edge connecting the bottom covering area 3 and the main covering area 1, and the side edges connecting the first side covering area 4 and the second side covering area 5 to the main covering area 1 are used as creases to wrap the battery cell group.

[0037] During wrapping, a battery cell group includes multiple single battery cells, wherein the width of the bottom wrapping area 3 is equal to the total thickness of the battery cells in the wrapped battery cell group, such as Figure 2 As shown, when the first insulating layer 10 and the second insulating layer 11 jointly cover two battery cell groups, the width of the bottom covering area 3 is equal to the sum of the battery cell thicknesses of the two battery cell groups, the bottom covering area 3 of the first insulating layer 10 completely covers the bottom covering area 3 of the second insulating layer 11, and the top covering area 2, the first side covering area 4 and the second side covering area 5 of the first insulating layer 10 at least partially cover the top covering area 2, the first side covering area 4 and the second side covering area 5 of the second insulating layer 11.

[0038] The thickness of the bottom coating area 3 of one insulating layer is 0.12-0.2 mm. During coating, the two bottom coating areas 3 overlap together, with a total thickness of 0.24-0.4 mm, which is consistent with the total thickness of the traditional insulating film and bottom support sheet combination, thus eliminating the need for a bottom support sheet. If the bottom coating area is too thin, powder dropped from the battery cell will easily accumulate in the through-hole, causing a short circuit between the aluminum shell and the battery cell, inducing corrosion of the lithium battery shell. If the bottom coating area is too thick, it will affect the internal space utilization of the lithium battery.

[0039] The bottom cladding area 3 and the top cladding area 2 are both provided with through holes, and the through holes are used to circulate electrolyte. At least one through hole is provided on each of the bottom cladding area 3 and the top cladding area 2. When multiple through holes are provided, the multiple through holes are evenly spaced and distributed on the bottom cladding area 3 and the top cladding area 2.

[0040] The provided through holes should neither affect the covering effect nor the strength of the insulating film. In a possible embodiment, the diameter of the provided through holes is 1 to 3 mm.

[0041] After the bottom coating region 3 is rotated 180° along its plane, at least some of its through-holes overlap with at least some of its through-holes before rotation. When coating the battery cell group, two insulating films jointly coat the battery cell group. The bottom coating regions 3 of the two insulating films have opposite coating directions. The coating direction of one insulating film is obtained by rotating the coating direction of the other insulating film 180°. At least some of the through-holes provided on the bottom coating region 3 of one insulating film overlap with at least some of the through-holes provided on the bottom coating region 3 of the other insulating film after rotation, thereby facilitating the flow of electrolyte.

[0042] In one possible embodiment, the width of the top coating region 2 is 2 to 5 mm greater than the total thickness of the cells of a cell group it encloses, so that when the first insulating layer 10 and the second insulating layer 11 jointly enclose two cell groups, there is partial overlap between the two top coating regions 2, allowing the cell groups to be completely enclosed between the two insulating films. Typically, the overlapping areas of the top coating regions are located outside the flow holes of the top coating regions. The flow holes on the top coating regions 2 of the first insulating layer 10 and the second insulating layer 11 may or may not overlap. The specific locations can be set according to actual conditions and are not specifically limited in this application.

[0043] In a possible embodiment, the widths of the first side coating area 4 and the second side coating area 5 are both 2 to 5 mm larger than the total thickness of the battery cells of a battery cell group they wrap, so that when the first insulating layer 10 and the second insulating layer 11 wrap the battery cell group, there is an overlapping area 9 between the two first side coating areas 4 and the second side coating areas 5, so that the battery cell group can be completely wrapped.

[0044] like Figure 1 As shown, the top covering area 2 is provided with two openings 7 for the tabs to pass through.

[0045] An adhesive layer is provided on the insulating layer. In a possible embodiment, the adhesive is double-sided adhesive. When pasting, one side of the double-sided adhesive is bonded to the inner surface of the insulating layer, and the other side is bonded to the outer surface of the battery cell.

[0046] like Figure 2 As shown, an embodiment of the present application shows a three-dimensional schematic diagram of a battery cell group wrapped with an insulating film. When wrapping, the first insulating layer 10 and the second insulating layer 11 jointly wrap two battery cell groups. Any wrapped battery cell group can be provided with a certain number of battery cells, and the other battery cell group has the same number and size of battery cells. The two top wrapping areas 2 are provided with openings, and the tabs 8 pass through the openings to avoid the problem of the tabs 8 being inserted into the battery cells upside down after the tabs 8 are bent and covered, causing the battery cells to short-circuit.

[0047] The present invention uses specific embodiments to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A lithium battery insulating film for coating a battery cell group, characterized in that: include: An insulating layer, the insulating layer comprising a main covering region and a bottom covering region, a top covering region, a first side covering region, and a second side covering region arranged around the main covering region, wherein the top edge of the main covering region is connected to the long edge of the top covering region, the bottom edge is connected to the long edge of the bottom covering region, the two side edges are respectively connected to the first side covering region and the second side covering region, and the width of the bottom covering region is greater than or equal to the total thickness of the cells of the covered battery cell group; An adhesive layer is provided on a side of the insulating layer that contacts the battery cell group.

2. A lithium battery insulating film according to claim 1, characterized in that: The thickness of the bottom coating area is 0.12-0.2 mm.

3. The lithium battery insulating film according to claim 1, characterized in that: Through holes are formed on both the bottom cladding area and the top cladding area. When the bottom cladding area is rotated 180° along its plane, at least part of the through holes after rotation overlap with at least part of the through holes before rotation.

4. The lithium battery insulating film according to claim 3, characterized in that: At least one through hole is provided on each of the bottom cladding area and the top cladding area. When two or more through holes are provided, the through holes are evenly spaced and distributed on the bottom cladding area and the top cladding area.

5. The lithium battery insulating film according to claim 1, characterized in that: The adhesive layer is arranged on the bottom covering area, the top covering area, the first side covering area and the second side covering area.

6. The lithium battery insulating film according to claim 1, characterized in that: The widths of the top covering area, the first side covering area and the second side covering area are all set to be 2-5 mm larger than the thickness of the battery cells of the battery cell group to be covered by them.

7. The lithium battery insulating film according to claim 1, characterized in that: The adhesive is a double-sided adhesive, one side of which is bonded to the inner surface of the insulating layer, and the other side of which is bonded to the outer surface of the battery cell group.

8. The lithium battery insulating film according to claim 1, characterized in that: The top covering area is provided with an opening, and the opening is used for passing the tab.

9. The lithium battery insulating film according to claim 1, characterized in that: The insulating film is a polyester film.

10. A lithium battery, characterized in that: The invention comprises a battery core and an insulating film according to any one of claims 1 to 9 coated on the outer surface of the battery core.

Images