Battery cell structure, battery and electric equipment
By setting a thickness compensation piece at the beginning of the winding of the battery cell, the problem of dark spots occurring during charging of the odd-folded battery cell is solved, and the battery performance is improved.
Patent Information
- Application Number
- CN202411735594.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-28
- Publication Date
- 2025-03-21
AI Technical Summary
Existing coiled odd-folded battery cells are prone to dark spots when charging, resulting in a degradation of battery performance.
By providing a thickness compensator at the beginning of winding of the battery cell and projecting its projection at least partially coincides with the projection of the cavity, to make up for the space of the cavity, increase the thickness of the overlapping region, and reduce the thickness difference between the overlapping region and other regions.
It effectively improves the lithium-ion problem of black spots, improves battery performance, and makes the battery cell feel more uniform during the transformation stage.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of batteries, and in particular to a battery core structure, a battery and an electrical device. Background Art
[0002] Generally, the battery cell includes a wound battery cell and a laminated battery cell. In the prior art, the wound battery cell is formed by winding the first pole piece, the diaphragm and the second pole piece stacked in sequence. When the first pole piece and / or the second pole piece are wound with an odd number of folds (hereinafter referred to as such a battery cell as a wound odd number of folds battery cell), and the winding start end and the winding end end are located on the same side of the battery cell, there is an overlapping area between the winding start end and the winding end end. In the thickness direction of the battery cell, there is a gap in the overlapping area to form a cavity, so that there is a thickness difference between the overlapping area of the battery cell and the other areas of the battery cell. The thinner the battery cell, the more obvious the difference. In the formation process of the battery production, the overlapping area of the battery cell is subjected to less pressure, and the other areas of the battery cell are subjected to greater pressure. In the overlapping area of the battery cell, the distance between the pole pieces is larger, and the lithium ion transmission distance is farther, resulting in the subsequent finished battery When charging, the pole pieces in the overlapping area of the battery cell are embedded with lithium more slowly, and then black spots appear. Especially during the battery cycle test, strip-shaped black spots will appear and lithium precipitation will occur. These black spots will cause the battery to swell and become thicker, seriously damaging the battery performance. Summary of the invention
[0003] The purpose of the present invention is to provide a battery cell structure, a battery and an electrical device, aiming to solve the technical problem in the prior art that black spots are easily generated in the battery cells wound with odd folds, resulting in serious degradation of battery performance.
[0004] In a first aspect, the present application provides a battery cell structure, comprising a battery cell and at least one thickness compensator, the battery cell comprising a first electrode sheet, a diaphragm and a second electrode sheet stacked in sequence, the first electrode sheet, the diaphragm and the second electrode sheet being wound to form a battery cell, the battery cell having a straight region and corner regions at opposite ends of the straight region, the winding starting end of the first electrode sheet being located in the straight region, and having a preset distance from the corner region to form a cavity, the cavity being located in the straight region, the thickness compensator being arranged at the winding starting end of the battery cell, wherein, along the thickness direction of the battery cell, the projection of the thickness compensator at least partially overlaps with the projection of the cavity.
[0005] The beneficial effect of the battery cell structure provided by the present invention is that one end of the straight area close to the corner area is the overlapping area mentioned in the background technology, and the cavity is located in the overlapping area. For the convenience of description and understanding, the area of the straight area other than the overlapping area is defined as other areas. In the present application, by setting a thickness compensating member at the winding starting end of the battery cell, and configuring the projection of the thickness compensating member in the thickness direction of the battery cell to at least partially overlap with the projection of the cavity in the thickness direction of the battery cell, it can be used to make up the space of the cavity, thereby increasing the thickness of the overlapping area of the battery cell during the formation stage, and then reducing the thickness difference between the overlapping area and other areas during the formation stage. The force on the entire battery cell during the formation stage can be made more uniform, which is conducive to making the lithium ion transmission path of the pole piece in the overlapping area close to the lithium ion transmission path of the pole piece in other areas, thereby effectively improving the problem of black spot lithium precipitation, and then improving battery performance.
[0006] In addition, in order to reduce the wrinkle degree of the electrode sheets in the overlapping area of the battery cell structure after formation, the thickness compensation piece is specially arranged at the winding start end of the battery cell. This is because if the thickness compensation piece is arranged on the outer surface of the battery cell, then when the battery cell is compressed during the formation stage, the electrode sheets in the overlapping area of the battery cell will gradually be pressed into the cavity, resulting in the electrode sheets in the overlapping area of the battery cell being not on the same horizontal plane as the electrode sheets in other areas of the battery cell.
[0007] Optionally, a thickness compensator is connected to the diaphragm.
[0008] Optionally, the first pole piece includes a first current collector and a first active material layer disposed on the first current collector, and the thickness compensation piece is connected to the first current collector.
[0009] Optionally, the second pole piece includes a second current collector and a second active material layer disposed on the second current collector, and the thickness compensation piece is connected to the second current collector.
[0010] Optionally, the thickness compensation piece includes an adhesive layer and an elastic layer connected to each other, and the elastic layer is bonded to the winding start end of the battery core through the adhesive layer.
[0011] Optionally, the material of the adhesive layer is organic glue.
[0012] Optionally, the elastic layer is made of one of silicone rubber, soft silicone, EVA, porous PE and plastic foam.
[0013] Optionally, the thickness of the adhesive layer is 2 to 20 microns.
[0014] Optionally, the elastic layer has a thickness of 80 to 300 micrometers.
[0015] Optionally, the thickness of the elastic layer is D1, and the thickness of the first pole piece is D2, satisfying the relationship: D1-D2=A, wherein A is 2 to 10 micrometers.
[0016] Optionally, the elastic layer has corrosion resistance, pressure resistance, oxidation resistance and insulation properties.
[0017] Optionally, in the direction from one corner area to another corner area, there is a preset distance L between the winding starting end of the first pole piece and the thickness compensation piece, L≥S+a, wherein S is the deformation of the thickness compensation piece before and after forming and hot pressing, 0<a≤4mm.
[0018] In a second aspect, the present application provides a battery, comprising the above-mentioned battery cell structure.
[0019] In a third aspect, the present application provides an electrical device including the above-mentioned battery. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative labor.
[0021] Figure 1 It is a schematic diagram of the structure of a battery cell in the related art;
[0022] Figure 2 A schematic diagram of the structure of a battery cell provided by an embodiment of the present invention;
[0023] Figure 3 Another structural schematic diagram of a battery cell structure provided by an embodiment of the present invention;
[0024] Figure 4 A schematic diagram of assembling a thickness compensation member and a first pole piece provided by an embodiment of the present invention;
[0025] Figure 5 Another schematic diagram of assembling the thickness compensation member and the first pole piece provided by the embodiment of the present invention;
[0026] Figure 6 Another schematic diagram of assembling the thickness compensation member and the first pole piece provided in an embodiment of the present invention.
[0027] Among them, the reference numerals in the figure are:
[0028] 100. Cell structure; 10. Cell; 20. Thickness compensation part;
[0029] 11. first pole piece; 12. diaphragm; 13. second pole piece;
[0030] 14. Straight area; 15. Corner area; 16. Cavity;
[0031] 111. first current collector; 112. first active material layer; 21. bonding layer;
[0032] 22. Elastic layer; 200. Overlapping area. DETAILED DESCRIPTION
[0033] Embodiments of the present invention are described in detail below, examples of which 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 intended to be used to explain the present invention, and should not be construed as limiting the present invention.
[0034] Reference throughout the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, when the phrases "in one embodiment" or "in some embodiments" appear in various places throughout the specification, not all references are to the same embodiment. Furthermore, in one or more embodiments, the particular features, structures, or characteristics may be combined in any suitable manner.
[0035] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention 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 should not be understood as a limitation on the present invention.
[0036] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.
[0037] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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 an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0038] Please refer to Figures 1 to 6Now, the battery cell structure 100, the battery and the electrical equipment in the embodiment of the present invention are described.
[0039] The battery cell structure 100 of the present application is suitable for winding an odd-number-folded battery cell 10 .
[0040] Please refer to Figures 1 to 3 The present application provides a battery cell structure 100, which includes a battery cell 10 and at least one thickness compensating member 20. The battery cell 10 includes a first electrode sheet 11, a diaphragm 12, and a second electrode sheet 13 stacked in sequence. The first electrode sheet 11, the diaphragm 12, and the second electrode sheet 13 are wound to form the battery cell 10. The battery cell 10 has a straight area 14 and corner areas 15 located at opposite ends of the straight area 14. The winding starting end of the first electrode sheet 11 is located in the straight area 14, and has a preset distance from the corner area 15 to form a cavity 16. The cavity 16 is located in the straight area 14. The thickness compensating member 20 is arranged at the winding starting end of the battery cell 10, wherein along the thickness direction of the battery cell 10, the projection of the thickness compensating member 20 at least partially overlaps with the projection of the cavity 16.
[0041] Specifically, in this embodiment, along the thickness direction of the battery cell 10, the projection of the thickness compensation member 20 is located within the projection of the cavity 16. The first electrode sheet 11 is a positive electrode sheet, and the first electrode sheet 11 is wound with an odd number of folds, that is, the first electrode sheet 11 is bent an odd number of times. Figure 2 For convenience of description and understanding, the first pole piece 11 is bent five times. One end of the straight area 14 close to the corner area 15 is the overlapping area 200 mentioned in the background technology, and the cavity 16 is located in the overlapping area 200. For convenience of description and understanding, the area of the straight area 14 other than the overlapping area 200 is defined as other areas.
[0042] In the present application, by setting a thickness compensating member 20 at the winding start end of the battery cell 10, and configuring the projection of the thickness compensating member 20 in the thickness direction of the battery cell 10 to at least partially overlap with the projection of the cavity 16 in the thickness direction of the battery cell 10, it can be used to make up for the space of the cavity 16, thereby increasing the thickness of the overlapping area 200 of the battery cell 10 during the formation stage, and then reducing the thickness difference between the overlapping area 200 and other areas during the formation stage. The force on the entire battery cell 10 during the formation stage can be made more uniform, which is conducive to making the lithium ion transmission path of the pole piece in the overlapping area 200 close to the lithium ion transmission path of the pole piece in other areas, thereby effectively improving the problem of black spot lithium precipitation, and then improving battery performance.
[0043] In addition, in order to reduce the wrinkle degree of the electrode pieces in the overlapping area 200 of the battery cell structure 100 after formation, the thickness compensating member 20 is disposed at the winding start end of the battery cell 10. This is because, if the thickness compensating member 20 is disposed on the outer surface of the battery cell 10, then when the battery cell 10 is pressed during the formation stage, the electrode pieces in the overlapping area 200 of the battery cell 10 will gradually be pressed into the cavity 16, resulting in the electrode pieces in the overlapping area 200 of the battery cell 10 and the electrode pieces in other areas of the battery cell 10 not being on the same horizontal plane.
[0044] Of course, the first electrode sheet 11 may also be a negative electrode sheet.
[0045] In another embodiment of the present application, please refer to Figure 2 and Figure 4 , the thickness compensation piece 20 is connected to the diaphragm 12 .
[0046] In another embodiment of the present application, please refer to Figure 5 The first pole piece 11 includes a first current collector 111 and a first active material layer 112 disposed on the first current collector 111, and the thickness compensation member 20 is connected to the first current collector 111. Specifically, the first current collector 111 is provided with the first active material layer 112 on both sides in its thickness direction.
[0047] In another embodiment of the present application, please refer to Figure 3 The second pole piece 13 includes a second current collector and a second active material layer disposed on the second current collector, and the thickness compensation member 20 is connected to the second current collector. Specifically, the second current collector is provided with the second active material layer on both sides in its thickness direction.
[0048] It can be understood that when the first current collector 111 is a positive electrode current collector, the first active material layer 112 is a positive electrode active material layer. When the first current collector 111 is a negative electrode current collector, the first active material layer 112 is a negative electrode active material layer. Similarly, the second current collector and the second active material layer are also the same, as long as the polarities of the first pole piece 11 and the second pole piece 13 are opposite.
[0049] It can be seen that the thickness compensation member 20 can be arranged on the first pole piece 11, the second pole piece 13, or the diaphragm 12. As long as the thickness compensation member 20 can make up for the space of the cavity 16, the position of the thickness compensation member 20 is not particularly limited.
[0050] When the thickness compensating member 20 is disposed on the diaphragm 12 , the amount of current collector used can be reduced, which is beneficial to reducing production costs.
[0051] When the connection strength between the used diaphragm 12 and the thickness compensation piece 20 is weak, for example, the diaphragm 12 has more surface ceramics, the thickness compensation piece 20 can be set on the first current collector 111 or the second current collector, which is beneficial to improve the stability of the thickness compensation piece 20.
[0052] In another embodiment of the present application, please refer to Figures 4 to 6 The thickness compensation member 20 includes an adhesive layer 21 and an elastic layer 22 connected to each other, and the elastic layer 22 is bonded to the winding start end of the battery cell 10 through the adhesive layer 21. Specifically, the elastic layer 22 is bonded to the diaphragm 12, the first current collector 111 or the second current collector through the adhesive layer 21. Since the battery formation pressure is very large, exceeding 1Mpa, a certain elastic deformation is required to prevent the thickness compensation member 20 from squeezing the pole piece, so the elastic layer 22 is provided to protect the pole piece and balance the pressure.
[0053] In another embodiment of the present application, the material of the adhesive layer 21 is organic glue. As an example, the material of the adhesive layer 21 can be rubber glue or silicone glue.
[0054] In another embodiment of the present application, the thickness of the adhesive layer 21 is 2 to 20 microns. As an example, the thickness of the adhesive layer 21 can be 2 microns, 4 microns, 6 microns, 8 microns, 10 microns, 12 microns, 14 microns, 16 microns, 18 microns, 20 microns, or a range between any two of the foregoing values. By controlling the thickness of the adhesive layer 21 within the above range, the amount of organic glue used can be reduced while ensuring the connection strength between the thickness compensation member 20 and the battery cell 10.
[0055] In another embodiment of the present application, the elastic layer 22 has corrosion resistance, pressure resistance, oxidation resistance and insulation performance. Since the thickness compensation member 20 is immersed in the electrolyte, the thickness compensation member 20 needs to have corrosion resistance. When the thickness compensation member 20 is connected to the positive electrode sheet, the elastic layer 22 needs to have oxidation resistance due to the high oxidation of the positive electrode. The elastic layer 22 needs to have insulation performance to prevent internal short circuit of the battery.
[0056] In another embodiment of the present application, the elastic layer 22 is made of one of silicone rubber, soft silicone, EVA, porous PE and plastic foam. The elastic layer 22 is preferably made of silicone rubber, which is chemically inert, does not react with the electrolyte, has a high temperature resistance of 300°C, and has good elasticity.
[0057] In another embodiment of the present application, the thickness of the elastic layer 22 is 80-300 microns. As an example, the thickness of the elastic layer 22 can be 80 microns, 100 microns, 120 microns, 140 microns, 160 microns, 180 microns, 200 microns, 220 microns, 240 microns, 260 microns, 280 microns, 300 microns, or a range between any two of the foregoing values.
[0058] In another embodiment of the present application, the thickness of the elastic layer 22 is D1, and the thickness of the first pole piece 11 is D2, satisfying the relationship: D1-D2=A, wherein A is 2 to 10 microns. Specifically, the battery cell 10 is composed of the second pole piece 13, the diaphragm 12 and the first pole piece 11 from the inside to the outside, wherein the first pole piece 11 is the positive pole piece and the second pole piece 13 is the negative pole piece. The thickness compensation member 20 is bonded to the diaphragm 12 and is located in the cavity 16. Alternatively, the thickness compensation member 20 is bonded to the first current collector 111 and is located in the cavity 16. By configuring the thickness of the elastic layer 22 to be greater than the thickness of the first pole piece 11, the thickness difference between the overlapping area 200 and other areas during the formation stage can be further reduced, thereby further improving the problem of black spot lithium precipitation.
[0059] As an example, the difference A between the thickness of the elastic layer 22 and the thickness of the first pole piece 11 can be 2 microns, 3 microns, 4 microns, 5 microns, 6 microns, 7 microns, 8 microns, 9 microns, 10 microns or a range between any two of the aforementioned values.
[0060] In another embodiment of the present application, please refer to Figure 1 , in the direction from one corner area 15 to another corner area 15, there is a preset distance L between the winding start end of the first pole piece 11 and the thickness compensation piece 20, L≥S+a, wherein S is the deformation of the thickness compensation piece 20 before and after the hot pressing, 0<a≤4mm. The direction from one corner area 15 to another corner area 15 is defined as the lateral direction, and the lateral deformation S of the thickness compensation piece 20 can be obtained by the following method: the thickness compensation piece 20 is placed on the battery forming cabinet, and the battery is hot pressed with the same pressure as the battery forming cabinet, and the width of the thickness compensation piece 20 before and after the hot pressing is measured, and the width before and after is subtracted, which is the lateral deformation S of the thickness compensation piece 20 after the hot pressing. a is the offset tolerance of the thickness compensation piece 20 attached to the production equipment. As an example, a can be 1mm, 2mm, 3mm, 4mm or a range between any two of the aforementioned values.
[0061] The present application also provides a battery, which includes the above-mentioned battery cell structure 100. Since the battery adopts the above-mentioned battery cell structure 100, the battery performance of the battery is improved.
[0062] The present application also provides an electric device, which includes the above-mentioned battery. The electric device may include but is not limited to mobile phones, tablets, laptops, electric toys, electric tools, battery cars, electric cars, ships, spacecraft, etc. Among them, electric toys may include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc., and spacecraft may include airplanes, rockets, space shuttles and spacecraft, etc.
[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A battery cell structure, characterized in that: include: A battery cell (10), comprising a first pole piece (11), a diaphragm (12) and a second pole piece (13) which are stacked in sequence, wherein the first pole piece (11), the diaphragm (12) and the second pole piece (13) are wound to form the battery cell (10), the battery cell (10) having a straight region (14) and corner regions (15) located at opposite ends of the straight region (14), a winding start end of the first pole piece (11) being located in the straight region (14) and having a preset distance from the corner region (15) to form a cavity (16), and the cavity (16) being located in the straight region (14); At least one thickness compensation piece (20) is arranged at the winding start end of the battery core (10); Wherein, along the thickness direction of the battery core (10), the projection of the thickness compensation piece (20) and the projection of the cavity (16) at least partially overlap.
2. The battery cell structure according to claim 1, characterized in that: The thickness compensating member (20) is connected to the diaphragm (12); or, The first pole piece (11) comprises a first current collector (111) and a first active material layer (112) arranged on the first current collector (111), and the thickness compensation member (20) is connected to the first current collector (111); or, The second pole piece (13) comprises a second current collector and a second active material layer arranged on the second current collector, and the thickness compensation piece (20) is connected to the second current collector.
3. The battery cell structure according to claim 1, characterized in that: The thickness compensation piece (20) comprises an adhesive layer (21) and an elastic layer (22) connected to each other, and the elastic layer (22) is bonded to the winding start end of the battery core (10) through the adhesive layer (21).
4. The battery cell structure according to claim 3, characterized in that: The material of the adhesive layer (21) is organic glue; and / or, The elastic layer (22) is made of one of silicone rubber, soft silicone, EVA, porous PE and plastic foam.
5. The battery cell structure according to claim 3, characterized in that: The thickness of the adhesive layer (21) is 2 to 20 micrometers; and / or, The thickness of the elastic layer (22) is 80 to 300 microns.
6. The battery cell structure according to claim 3, characterized in that: The thickness of the elastic layer (22) is D1, and the thickness of the first pole piece (11) is D2, satisfying the relationship: D1-D2=A, wherein A is 2 to 10 micrometers.
7. The battery cell structure according to claim 4, characterized in that: The elastic layer (22) has corrosion resistance, pressure resistance, oxidation resistance and insulation properties.
8. The battery cell structure according to claim 1, characterized in that: In the direction from one corner area (15) to the other corner area (15), there is a preset distance L between the winding start end of the first pole piece (11) and the thickness compensation piece (20), L≥S+a, wherein S is the deformation amount of the thickness compensation piece (20) before and after forming hot pressing, and 0<a≤4mm.
9. A battery, characterized in that: It comprises the battery cell structure (100) as claimed in any one of claims 1 to 8.
10. An electrical equipment, characterized in that: Comprising the battery as claimed in claim 9.