CN-122025543-A - Positive electrode sheet and secondary battery

Abstract

The present application relates to a positive electrode sheet and a secondary battery. The positive plate comprises a positive current collector and a positive active material layer coated on at least one surface of the positive current collector, wherein an embossing structure is arranged on the surface of the positive active material layer, and the embossing structure comprises a plurality of embossing grooves and guide grooves connected with the adjacent embossing grooves so that electrolyte can flow between different embossing grooves through the guide grooves. According to the scheme provided by the application, the uniformity of the distribution of the electrolyte on the positive plate can be improved.

Inventors

• CHEN HAO
• ZHANG CHANGMING
• HU DALIN
• LIAO XINGQUN

Assignees

• 深圳市豪鹏科技股份有限公司

Dates

Publication Date

20260512

Application Date

20260305

Claims (10)

1. 1. The positive plate is characterized by comprising a positive current collector and a positive active material layer coated on at least one surface of the positive current collector, wherein the surface of the positive active material layer is provided with an embossing structure; The embossing structure comprises a plurality of embossing grooves and diversion trenches connected with the adjacent embossing grooves, so that electrolyte can flow between different embossing grooves through the diversion trenches.
2. 2. The positive electrode sheet according to claim 1, wherein: the embossing grooves are connected end to end through the diversion trenches and are communicated in a series mode.
3. 3. The positive electrode sheet according to claim 1, wherein: The embossing grooves are arranged in a rectangular array, and are sequentially communicated along a serpentine extending path through the diversion trenches.
4. 4. The positive electrode sheet according to claim 1, wherein: The cross section shape of the embossing groove and the cross section shape of the diversion trench are arc-shaped.
5. 5. The positive electrode sheet according to claim 1, wherein: The embossing grooves are hemispherical grooves, and the diversion trenches are semi-cylindrical grooves.
6. 6. The positive electrode sheet according to claim 1, wherein: The depth H 1 of the embossing grooves is 40-70 mu m, the width W 1 of the embossing grooves is 160-140 mu m, and the distance L 1 between two adjacent embossing grooves is 290-740 mu m; The length L 2 of the diversion trench is 250-600 mu m, the depth H 2 is 20-60 mu m, and the width W 2 is 40-120 mu m.
7. 7. The positive electrode sheet according to claim 1, wherein: The positive electrode current collector is made of aluminum foil, and the thickness of the positive electrode current collector is 8-16 mu m.
8. 8. The positive electrode sheet according to claim 1, wherein: The positive electrode active material layer is provided with a tab area, a first embossing area and a second embossing area, and the first embossing area and the second embossing area are respectively provided with the embossing structure; The first embossed area is arranged close to a first end of the positive electrode active material layer, the second embossed area is arranged close to a second end of the positive electrode active material layer, and the first end and the second end are oppositely arranged in the length direction of the positive electrode plate; The tab region is located between the first embossed region and the second embossed region.
9. 9. The positive electrode sheet according to claim 8, wherein: The distance X 1 between the first embossed area and the tab area is 5 mm-40 mm, and the distance X 2 between the second embossed area and the tab area is 5 mm-40 mm; The distance X 3 between the first embossing area and the first end is 5 mm-40 mm, and the distance X 4 between the second embossing area and the second end is 5 mm-40 mm; The distance Y 1 between the first embossed area and the edge of the positive electrode active material layer, which is provided with the tab area, is 2 mm-10 mm, and the distance Y 2 between the second embossed area and the edge of the positive electrode active material layer, which is provided with the tab area, is 2 mm-10 mm.
10. 10. A secondary battery according to any one of claim 1 to 9, comprising a positive electrode sheet.

Description

Positive electrode sheet and secondary battery Technical Field The application relates to the technical field of batteries, in particular to a positive plate and a secondary battery. Background With the rapid development of the fields of new energy automobiles, energy storage power stations and the like, higher requirements are put forward on the energy density, cycle life and rate capability of secondary batteries (particularly lithium ion batteries). The structural design of the battery pole piece is one of the key factors influencing the battery performance. In the related art, in order to increase the strength of the pole piece, prevent the coating from falling off, and improve the wettability and the liquid-retaining capacity of the pole piece and the electrolyte, embossing treatment is generally performed on the pole piece. The embossing process can store electrolyte to a certain extent by forming a series of regular micro grooves or indentations on the surface of the pole piece, so that the liquid-retaining capacity of the battery is improved, and the embossing process has positive effects on the long-term cycle performance of the battery. However, when the embossed pole piece in the related technology is adopted, the electrolyte is unevenly distributed in different areas of the pole piece, the electrolyte is enriched in partial areas, and the dry areas possibly appear in partial areas, meanwhile, the consumption of the electrolyte in different areas is inconsistent, the uneven distribution of the electrolyte is further aggravated along with the increase of circulation cycles, and the uneven distribution of the electrolyte on the pole piece can influence the performance and the safety of a battery. Disclosure of Invention In order to solve or partially solve the problems existing in the related art, the application provides a positive plate and a secondary battery, which can improve the uniformity of distribution of electrolyte on the positive plate. The first aspect of the application provides a positive plate, which comprises a positive current collector and a positive active material layer coated on at least one surface of the positive current collector, wherein the surface of the positive active material layer is provided with an embossing structure; The embossing structure comprises a plurality of embossing grooves and diversion trenches connected with the adjacent embossing grooves, so that electrolyte can flow between different embossing grooves through the diversion trenches. Further, the embossing grooves are connected end to end through the diversion trenches and are communicated in a series mode. Further, the embossing grooves are arranged in a rectangular array, and the embossing grooves are sequentially communicated along a serpentine extending path through the diversion trenches. Further, the cross section shape of the embossing groove and the cross section shape of the diversion trench are arc-shaped. Further, the embossing grooves are hemispherical grooves, and the diversion trenches are semi-cylindrical grooves. Further, the depth H 1 of the embossing grooves is 40-70 μm, the width W 1 of the embossing grooves is 160-140 μm, and the distance L 1 between two adjacent embossing grooves is 290-740 μm; The length L 2 of the diversion trench is 250-600 mu m, the depth H 2 is 20-60 mu m, and the width W 2 is 40-120 mu m. Further, the positive electrode current collector is made of aluminum foil, and the thickness of the positive electrode current collector is 8-16 microns. Further, a tab region, a first embossing region and a second embossing region are arranged on the surface of the positive electrode active material layer, and the first embossing region and the second embossing region are both provided with the embossing structure; The first embossed area is arranged close to a first end of the positive electrode active material layer, the second embossed area is arranged close to a second end of the positive electrode active material layer, and the first end and the second end are oppositely arranged in the length direction of the positive electrode plate; The tab region is located between the first embossed region and the second embossed region. Further, a distance X 1 between the first embossed area and the tab area is 5 mm-40 mm, and a distance X 2 between the second embossed area and the tab area is 5 mm-40 mm; The distance X 3 between the first embossing area and the first end is 5 mm-40 mm, and the distance X 4 between the second embossing area and the second end is 5 mm-40 mm; The distance Y 1 between the first embossed area and the edge of the positive electrode active material layer, which is provided with the tab area, is 2 mm-10 mm, and the distance Y 2 between the second embossed area and the edge of the positive electrode active material layer, which is provided with the tab area, is 2 mm-10 mm. A second aspect of the present application provides a secondary battery compris