A positive electrode sheet and a lithium-ion battery comprising the positive electrode sheet

Abstract

The invention provides a positive electrode sheet and a lithium ion battery comprising the positive electrode sheet; the positive electrode sheet is in the area near the positive electrode tab (such as the A coating area) and the area away from the positive electrode tab (such as the B coating area). Covering area) respectively use lithium cobalt oxide with different metal element coating doping amounts. Within a certain range, the working platform voltage of lithium cobalt oxide with a higher content of doped metal elements is high, which can improve its stability at high potential (the area near the positive electrode tab). Therefore, Coating lithium cobalt oxide with higher doping metal content in the area near the positive tab (such as the A coating area) can effectively improve the cycle stability. In addition, due to the increase in the total amount of coated and doped metals of the lithium cobalt oxide coated on the positive electrode tab, its gram capacity will decrease accordingly, and the ratio of the areal capacity of the negative electrode to the areal capacity of the positive electrode at this place will increase, so that it can effectively The problem of lithium decomposing in the single-sided area of ​​the corresponding negative electrode sheet is improved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a positive electrode sheet and a lithium ion battery including the positive electrode sheet. 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, it has become a market demand to configure lithium-ion batteries with high-efficiency charging capabilities. However, during the cycle of lithium-ion batteries with a conventional winding structure, especially when charging, the current density at the positive electrode near the negative electrode ear is relatively high, which is easy to decompose lithium, which in turn affects the performance of lithium-ion batteries. Moreover, when charging, the potentials of lithium cobaltate at different positions in the positive electrode sheet are different, and the potential near the po...

AI Technical Summary

Problems solved by technology

However, during the cycle of lithium-ion batteries with conventional winding structures, especially when charging, the current density of the positive electrode near the negative electrode ear is relatively large, which is easy to decompose lithium, which in turn affects the performance of lithium-ion batteries.

Moreover, when charging, the potentials of lithium cobaltate at different positions in the positive electrode sheet are different, and the potential near the positive ear is higher. The structure of lithium cobaltate in these places is easily damaged, and metal cobalt is easy to dissolve, which is easy to cause lithium-ion batteries. decay of cycle capacity

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