Lithium-ion battery cathode sheet, preparation method thereof, and lithium-ion battery

Abstract

The invention provides a positive electrode sheet of a lithium ion battery, a preparation method thereof, and a lithium ion battery. The positive electrode sheet of the lithium ion battery includes a current collector and an active material layer coated on at least one surface of the current collector. The thinned area at the edge of both sides of the fluid surface and the unthinned area connected with the thinned area at the edge on both sides, the areal density of the active material in the thinned area is smaller than the area density of the active material in the unthinned area; the thinned The region gradually widens along the length of the current collector and its widest point is located at the end of the current collector near the tab. The invention can effectively alleviate the problem of lithium deposition at the edge of the battery core and at the tab while ensuring that the energy density of the positive electrode sheet 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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