Lithium ion battery positive plate, preparation method thereof and lithium ion battery

Abstract

The invention provides a lithium ion battery positive plate, a preparation method thereof and a lithium ion battery. The lithium ion battery positive plate comprises a current collector and an activematerial layer coated on at least one surface of the current collector, the active material layer is composed of thinning areas located on the edges of the two sides of the surface of the current collector and non-thinning areas connected with the thinning areas on the edges of the two sides, and the surface density of the active material of the thinning areas is smaller than that of the active material of the non-thinning areas. The thinning area is gradually widened along the length direction of the current collector; and the widest part of the thinning area is positioned at one end of the current collector close to the tab. According to the invention, the problem of lithium precipitation at the edge and tabs of the battery cell can be effectively relieved while the energy density of thepositive plate is not greatly reduced.

Description

technical field [0001] The invention relates to the field of batteries, in particular to a lithium-ion battery positive plate, a preparation method thereof, and a lithium-ion battery. Background technique [0002] With the advent of the electronic age, portable power sources have been applied to all aspects of life. At present, on the basis of meeting the energy density, lithium-ion batteries with more and more efficient charging capabilities have become more and more demanded products in the market. The winding lithium-ion battery is characterized by combining the positive and negative electrodes by winding, which has the advantages of high production efficiency and low cost, and has become one of the commonly used battery types at present. However, the current density distribution of traditional winding lithium-ion batteries is uneven, especially at the edge of the battery pole piece and the current density near the tabs gradually increases. The problem of lithium analysi...

AI Technical Summary

Problems solved by technology

However, the current density distribution of traditional winding lithium-ion batteries is uneven, especially at the edge of the battery pole piece and the current density near the tabs gradually increases. The problem of lithium analysis at the pole ear

At present, the industry mainly reduces the risk of lithium precipitation by increasing the CB value of the positive and negative electrodes (that is, the ratio of the active material capacity of the negative electrode to the active material capacity of the positive electrode). However, increasing the CB value of the electrode as a whole will significantly reduce the battery capacity. The energy density is high, and the improvement of the lithium deposition problem at the edge of the battery cell and the tab is not obvious

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