CN219329274U

CN219329274U - Battery pole piece and battery

Info

Publication number: CN219329274U
Application number: CN202320176575.3U
Authority: CN
Inventors: 姚煜; 邓国友; 殷晓丰; 慎晓杰; 蔡祥槟
Original assignee: Microvast Power Systems Huzhou Co Ltd
Current assignee: Microvast Power Systems Huzhou Co Ltd
Priority date: 2023-01-13
Filing date: 2023-01-13
Publication date: 2023-07-11
Anticipated expiration: 2033-01-13

Abstract

The utility model provides a battery pole piece, which comprises a current collector, wherein the current collector comprises a plurality of coating areas and at least one punching area, the coating areas and the punching area are arranged in a width direction of the current collector, and the punching area is arranged between two adjacent coating areas; the surface of the coating area is provided with an active substance layer, the punching area is provided with a through hole, and the surface of the punching area is provided with a thickening layer. The utility model also provides a battery.

Description

Battery pole piece and battery

Technical Field

The utility model relates to the technical field of batteries, in particular to a battery pole piece and a battery.

Background

The lithium ion battery has the advantages of long service life and high specific energy, the application field of the lithium ion battery is wider and wider, and the application scale in the energy storage field is gradually enlarged. Energy storage batteries require large capacity and low production costs, and therefore the cells tend to be wound with large pole pieces. The winding battery core is long in pole piece, so that electrolyte can only enter the battery core from the upper end and the lower end of the battery core during liquid injection, and the battery core can be fully soaked after the battery core is placed for a long time after liquid injection.

The current common solution is to punch holes in the middle area of a battery pole piece (comprising a positive pole piece and a negative pole piece) before coating, wherein the middle punching area is not coated when the pole piece is coated, and the coated positive pole piece and negative pole piece are wound into a battery core together with a diaphragm. When the battery cell prepared by the method is filled with electrolyte, the electrolyte can enter the battery cell from the upper end, the lower end and the middle pore of the battery cell, so that the way of entering the electrolyte is increased, the time of electrolyte infiltration can be shortened, the infiltration sufficiency is improved, and part of electrolyte can be stored in the middle punching area, thereby improving the production efficiency and the cycle performance of the battery cell. However, when the coated positive plate and the coated negative plate are wound into the battery core together with the diaphragm, the diaphragm and/or the pole piece are easy to wrinkle during winding due to the thickness difference between the middle punching area and the coating area, so that the conduction and transportation of lithium ions are affected, lithium crystallization is easy to cause, and the cycle performance of the battery is affected.

Disclosure of Invention

The utility model aims to provide a battery pole piece, wherein a thickening layer is arranged on the surface of a punching area, so that the thickness difference between the position of a coating area and the position of the punching area of the battery pole piece is reduced or eliminated, and the generation of wrinkles of a diaphragm and/or the pole piece during winding is reduced or avoided.

One embodiment of the utility model provides a battery pole piece, which comprises a current collector, wherein the current collector comprises a plurality of coating areas and at least one punching area, the coating areas and the punching area are arranged along the width direction of the current collector, and the punching area is arranged between two adjacent coating areas; the surface of the coating area is provided with an active substance layer, the punching area is provided with a through hole, and the surface of the punching area is provided with a thickening layer.

In one possible embodiment, the thickening layer has a liquid-absorbing function, and the thickening layer is capable of absorbing an electrolyte.

In one possible embodiment, the ratio of the thickness of the thickening layer to the thickness of the active substance layer is 0.9 to 1.1. The ratio of the thickness of the thickening layer to the thickness of the active material layer is less than 0.9, which is insufficient to reduce the thickness difference between the coating region position and the punching region position, and to reduce or avoid the poor effect of generating wrinkles on the separator and/or the pole piece during winding; if the ratio of the thickness of the thickening layer to the thickness of the active material layer is greater than 1.1, a gap is likely to be generated between the positive and negative electrode active materials and the separator, and the resistance is increased, so that the battery capacity cannot be fully exerted, and the battery performance is affected.

In one realisable form, the active material layer has a thickness of 30 μm to 100 μm; and/or the thickness of the thickening layer is 27-110 μm.

In one possible way, the thickening layer is a nonwoven or a wood fiber paper.

In one implementation manner, the nonwoven fabric is made of polyethylene, polypropylene, polyacrylonitrile, polyamide, polyvinyl chloride or polyethylene terephthalate.

In one implementation, the active material layer is disposed on a surface of the coating region on one side, the thickening layer is disposed on a surface of the perforated region on one side, and the active material layer and the thickening layer are located on the same side of the current collector;

alternatively, the active material layer is disposed on the surfaces of the opposite sides of the coating region, and the thickening layer is disposed on the surfaces of the opposite sides of the perforated region.

In one implementation, the current collector further includes a tab region, the tab region being an empty foil region; and the tab area is arranged adjacent to the coating area along the width direction of the current collector.

In one implementation, the perforated area is provided with a plurality of through holes, and the plurality of through holes are arranged at intervals along the length direction of the current collector.

In one possible embodiment, the thickening layer is adhesively secured to the surface of the perforated region.

In one implementation, the battery pole piece is a positive pole piece and/or a negative pole piece.

Another embodiment of the present utility model further provides a battery, including a positive electrode sheet and a negative electrode sheet, where the positive electrode sheet and/or the negative electrode sheet are the battery electrode sheets described above.

According to the battery pole piece provided by the utility model, the thickening layer is arranged on the surface of the punching area, so that the thickness difference between the position of the battery pole piece corresponding to the coating area and the position of the punching area is reduced or eliminated, the problem that the diaphragm is wrinkled when being wound together with the battery pole piece is reduced or avoided, the possibility that the punching area of the pole piece generates the wrinkled is also reduced, and the safety performance and the cycle performance of the battery are improved.

Drawings

Fig. 1 is a schematic plan view of a battery pole piece according to an embodiment of the present utility model.

Fig. 2 is a schematic cross-sectional view of fig. 1.

Fig. 3 is a schematic plan view of a battery pole piece according to another embodiment of the present utility model.

Fig. 4 is a schematic cross-sectional view of a battery pole piece in another embodiment of the utility model.

Fig. 5 is a schematic plan view of a positive plate according to an embodiment of the present utility model.

Fig. 6 is a schematic plan view of a negative plate according to an embodiment of the present utility model.

Fig. 7 is a schematic structural diagram of a stacked positive electrode sheet and negative electrode sheet according to an embodiment of the present utility model.

Fig. 8 is a schematic structural diagram of the positive electrode sheet, the negative electrode sheet and the separator when winding in the embodiment of the utility model.

Detailed Description

The following describes in further detail the embodiments of the present utility model with reference to the drawings and examples. The following examples are illustrative of the utility model and are not intended to limit the scope of the utility model.

The terms "first," "second," "third," "fourth" and the like in the description and in the claims, if any, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order.

The terms upper, lower, left, right, front, rear, top, bottom and the like (if any) in the description and in the claims are used for descriptive purposes and not necessarily for describing relative positions of structures in the figures and in describing relative positions of structures. It should be understood that the use of directional terms should not be construed to limit the scope of the utility model as claimed.

As shown in fig. 1 and fig. 2, the battery pole piece provided by the embodiment of the utility model comprises a current collector 1, wherein the current collector 1 comprises a plurality of coating areas 11 and at least one punching area 12, the coating areas 11 and the punching area 12 are arranged along the width direction W of the current collector 1, and the punching area 12 is arranged between two adjacent coating areas 11. The active material layer 2 is provided on the surface of the coating region 11, the perforated region 12 is an empty foil region (i.e. no active material is provided on the surface of the perforated region 12), the perforated region 12 is provided with a through hole 121, and the surface of the perforated region 12 is provided with a thickening layer 3.

Specifically, the thickening layer 3 is arranged on the surface of the punching area 12, so that the thickness difference between the position of the battery pole piece corresponding to the coating area 11 and the position of the punching area 12 is reduced or eliminated, the problem that the diaphragm is wrinkled when being wound together with the battery pole piece is reduced or avoided, the possibility that the punching area of the pole piece generates the wrinkled is reduced, and the safety performance and the cycle performance of the battery are improved.

As an embodiment, the thickening layer 3 has a liquid absorbing function, and the thickening layer 3 is capable of absorbing an electrolyte. Since the thickening layer 3 can absorb the electrolyte, the electrolyte infiltration speed can be increased when the electrolyte is filled, and the electrolyte can diffuse through the through holes 121, so that the sufficient infiltration of the battery cells is ensured.

As an embodiment, the thickening layer 3 is a nonwoven fabric or a wood fiber paper. Wherein, the non-woven fabric can be made of Polyethylene (PE), polypropylene (PP), polyacrylonitrile (PAN), polyamide (PA), polyvinyl chloride (PVC) or polyethylene terephthalate (PET).

As an embodiment, the ratio of the thickness of the thickening layer 3 to the thickness of the active material layer 2 is 0.9-1.1, so that the thickness of the thickening layer 3 is equivalent to the thickness of the active material layer 2, thereby avoiding the membrane from generating wrinkles due to too large thickness difference at each surface position of the battery pole piece when the membrane is wound together with the battery pole piece, and reducing the possibility of generating wrinkles in the pole piece punching area. The ratio of the thickness of the thickening layer 3 to the thickness of the active material layer 2 is 0.9-1.1, so that the thickness difference between the coating area position and the punching area position can be further reduced, and the effect of reducing or avoiding the generation of wrinkles of the diaphragm and/or the pole piece during winding is better; meanwhile, the interval between the positive and negative active substances and the diaphragm is not easy to generate, the impedance is further reduced, the battery capacity cannot be fully exerted, and the cycle performance of the battery is improved.

As an embodiment, the thickness of the active material layer 2 is 30 μm to 100 μm, or 40 μm to 90 μm, or 40 μm to 80 μm.

As an embodiment, the thickness of the thickening layer 3 is 27 μm to 110 μm, or 36 μm to 99 μm, or 36 μm to 88 μm.

As shown in fig. 1 and 2, as an embodiment, the number of the coating areas 11 is two, and the two coating areas 11 are spaced apart; the number of perforated areas 12 is one, and one perforated area 12 is disposed between the two coating areas 11. Of course, in other embodiments, the number of coating regions 11 and perforated regions 12 may be greater, with each perforated region 12 being disposed between two adjacent coating regions 11.

As shown in fig. 2, as an embodiment, the active material layer 2 is disposed on the surface of the coating region 11 on one side, the thickening layer 3 is disposed on the surface of the perforated region 12 on one side, and the active material layer 2 and the thickening layer 3 are located on the same side of the current collector 1.

As another embodiment, as shown in fig. 4, the active material layer 2 is disposed on the surfaces of the opposite sides of the coating region 11, and the thickening layer 3 is disposed on the surfaces of the opposite sides of the perforated region 12.

As shown in fig. 1, as an embodiment, the current collector 1 further includes a tab region 13, where the tab region 13 is a blank foil region (i.e., no active material is disposed on a surface of the tab region 13), and the tab region 13 is used for cutting to form a tab. In the width direction W of the current collector 1, the tab region 13 is disposed adjacent to the coating region 11, and the tab region 13 is located at one side of the coating region 11.

As shown in fig. 1, as an embodiment, the perforated region 12 is provided with a plurality of through holes 121, and the plurality of through holes 121 are arranged at intervals along the length direction L of the current collector 1.

As shown in fig. 3, as another embodiment, the perforated region 12 is provided with a plurality of through holes 121, and the plurality of through holes 121 are arranged in a plurality of rows and a plurality of columns in the width direction W and the length direction L of the current collector 1. The pitch between two adjacent through holes 121 in each row is 10mm, the pitch between two adjacent through holes 121 in each column is 1mm, and the diameter of the through holes 121 is 0.1mm to 0.5mm.

As an embodiment, the shape of the through hole 121 may be circular, elliptical, rectangular, trapezoidal, or the like.

Of course, in other embodiments, the number, positions of the perforated sections 12, and the shape, number, diameter, and pitch of the through holes 121 may not be particularly limited.

As an embodiment, the thickening layer 3 is adhesively fastened to the surface of the perforated region 12. Of course, in other embodiments, the thickening layer 3 may be secured to the surface of the perforated section 12 in other ways.

As shown in fig. 1 and 2, as an embodiment, the area of the thickening layer 3 is equal to the area of the perforated area 12 (i.e., the thickening layer 3 completely covers the surface of the perforated area 12). Of course, in other embodiments, the area of thickening layer 3 may also be smaller than the area of perforated area 12 (i.e., thickening layer 3 partially covers the surface of perforated area 12). As an embodiment, the area of the thickening layer 3 is greater than or equal to 90% of the area of the perforated area 12.

As one embodiment, the battery pole piece is a positive pole piece and/or a negative pole piece.

As shown in fig. 5 to 8, the present embodiment further provides a battery including a positive electrode sheet 4 and a negative electrode sheet 5, where the positive electrode sheet 4 and/or the negative electrode sheet 5 are the battery electrode sheets described above.

As shown in fig. 5 and 6, as an embodiment, the positive electrode sheet 4 and the negative electrode sheet 5 are both the battery electrode sheets described above. The positive electrode tab 4 is provided with a positive electrode tab 41, and the negative electrode tab 5 is provided with a negative electrode tab 51 (the positive electrode tab 41 and the negative electrode tab 51 are formed by cutting a tab region of a battery electrode tab).

As shown in fig. 8, as an embodiment, the battery is a wound battery formed by stacking and winding a positive electrode sheet 4, a negative electrode sheet 5, and a separator 6.

Specifically, as shown in fig. 7 in combination with fig. 1, in the present embodiment, the width of the perforated area on the positive electrode sheet 4 is 5mm to 7mm, and the width of the perforated area on the negative electrode sheet 5 is 3mm to 5mm, i.e., the width of the perforated area on the positive electrode sheet 4 is 2mm larger than the width of the perforated area on the negative electrode sheet 5; when the positive plate 4 and the negative plate 5 are overlapped, the punching area on the positive plate 4 is overlapped with the punching area on the negative plate 5, and the coating area on the negative plate 5 wraps the coating area on the positive plate 4. As shown in fig. 8, when the positive electrode sheet 4, the negative electrode sheet 5 and the separator 6 are stacked in the order of the positive electrode sheet 4-separator 6-negative electrode sheet 5-separator 6, they are wound again to obtain the wound battery cell. In the practical structure, after lamination of the positive and negative plates, when the negative plate 5 is laminated on the positive plate 4, the positive plate 4 located below the lamination and completely shielded by the negative plate 5 cannot be seen from fig. 7 because the size of the negative plate 5 is larger than that of the positive plate 4. In fig. 7, the cathode sheet 5 is covered above the anode sheet 4, and when overlapping of the anode sheet and the cathode sheet is convenient to understand through perspective, the width of the punching area of the cathode sheet 5 is smaller than that of the punching area of the anode sheet 4, and the width of the coating area of the cathode sheet 5 is larger than that of the coating area of the anode sheet 4.

As another embodiment, the battery may be a laminated battery formed by stacking the positive electrode sheet 4, the negative electrode sheet 5, and the separator 6.

According to the battery pole piece provided by the embodiment of the utility model, the thickening layer 3 is arranged on the surface of the punching area 12, so that the thickness difference between the position of the battery pole piece corresponding to the coating area 11 and the position of the punching area 12 is reduced or eliminated, the problem that the diaphragm is wrinkled when being wound together with the battery pole piece is reduced or avoided, the possibility that the pole piece punching area generates the wrinkled is also reduced, and the safety performance and the cycle performance of the battery are improved. Meanwhile, since the thickening layer 3 can absorb the electrolyte, the electrolyte infiltration speed can be increased when the electrolyte is filled, and the electrolyte can be diffused through the through holes 121, so that the sufficient infiltration of the battery cells is ensured.

The foregoing is merely illustrative embodiments of the present utility model, but the scope of the present utility model is not limited thereto, and any person skilled in the art can easily think about variations or substitutions within the technical scope of the present utility model, and the utility model should be covered. Therefore, the protection scope of the utility model is subject to the protection scope of the claims.

Claims

1. A battery pole piece comprising a current collector (1), characterized in that the current collector (1) comprises a plurality of coating areas (11) and at least one punching area (12), the coating areas (11) and the punching area (12) are arranged along the width direction (W) of the current collector (1), and the punching area (12) is arranged between two adjacent coating areas (11); the surface of the coating area (11) is provided with an active substance layer (2), the perforated area (12) is provided with a through hole (121), and the surface of the perforated area (12) is provided with a thickening layer (3).

2. A battery pole piece according to claim 1, characterized in that the thickening layer (3) has a liquid-absorbing function, the thickening layer (3) being capable of absorbing electrolyte.

3. A battery pole piece according to claim 1, characterized in that the ratio of the thickness of the thickening layer (3) to the thickness of the active material layer (2) is 0.9-1.1.

4. The battery pole piece according to claim 1, characterized in that the thickness of the active material layer (2) is 30 μm-100 μm; and/or the thickness of the thickening layer (3) is 27-110 μm.

5. A battery pole piece according to claim 1, characterized in that the thickening layer (3) is a non-woven fabric or a wood fiber paper.

6. The battery pole piece of claim 5, wherein the nonwoven fabric is made of polyethylene, polypropylene, polyacrylonitrile, polyamide, polyvinyl chloride or polyethylene terephthalate.

7. The battery pole piece according to claim 1, characterized in that the active material layer (2) is arranged on the surface of the coating region (11) on one side, the thickening layer (3) is arranged on the surface of the perforated region (12) on one side, and the active material layer (2) and the thickening layer (3) are located on the same side of the current collector (1);

alternatively, the active material layer (2) is disposed on the surfaces of the opposite sides of the coating region (11), and the thickening layer (3) is disposed on the surfaces of the opposite sides of the perforated region (12).

8. The battery pole piece according to claim 1, wherein the current collector (1) further comprises a tab region (13), the tab region (13) being a blank foil region; the tab region (13) is disposed adjacent to the coating region (11) in the width direction (W) of the current collector (1).

9. The battery pole piece according to claim 1, wherein the perforated area (12) is provided with a plurality of the through holes (121), and the plurality of through holes (121) are arranged at intervals along the length direction (L) of the current collector (1).

10. A battery pole piece according to claim 1, characterized in that the thickening layer (3) is adhesively secured to the surface of the perforated area (12).

11. The battery pole piece of any of claims 1-10, wherein the battery pole piece is a positive pole piece and/or a negative pole piece.

12. A battery comprising a positive electrode sheet and a negative electrode sheet, wherein the positive electrode sheet and/or the negative electrode sheet is the battery sheet according to any one of claims 1 to 11.