Positive plate and lithium ion battery comprising positive plate

Abstract

The invention provides a positive plate and a lithium ion battery comprising the positive plate. According to the positive plate, lithium cobalt oxides with different metal element coating doping amounts are used in a region (such as a coating region A) close to a positive tab and a region (such as a coating region B) far away from the positive tab respectively. Within a range, the voltage of a working platform of lithium cobalt oxides with higher content of coated and doped metal elements is high, therefore, the stability of the working platform under high potential (the region close to the positive tab) can be improved, so that the cycling stability can be effectively improved by coating the region (such as the coating region A) close to the positive tab with lithium cobalt oxides with higher coated and doped metal content. Besides, the gram volume of the lithium cobalt oxides coated at the positive tab is correspondingly reduced due to the increase of the total amount of the coatedand doped metal, and a ratio of the surface capacity of a negative pole to the surface capacity of a positive pole is increased, so that the problem of lithium precipitation in a single-sided region in the corresponding negative pole piece can be effectively 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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