Pole piece with novel conductive agent distribution structure and lithium ion battery comprising pole piece

Abstract

The invention provides a pole piece with a novel conductive agent distribution structure and a lithium ion battery comprising the pole piece. The pole piece comprises a current collector and coatingsarranged at the two sides of the current collector, and each coating comprises an active substance, a conductive agent and a binder. In the thickness direction of the coating, the coating comprises ahigh-conductivity agent region and a low-conductivity agent region, by changing the distribution of the conductive agent in the thickness direction of the pole piece coating, the conductive networks with different densities are constructed, and it is tested that the more sufficient conductive network with higher density is constructed in an area with high polarization degree, the content of the conductive agent is reduced in an area with low polarization degree, and a conductive network with lower density is constructed. In other words, different formulas can be designed according to the performance requirements of customers at the high-temperature and low-temperature aspects of the battery cell, and are matched to enter a chemical system at the same time, so that the goals of high-temperature and low-temperature performance consideration, high energy density consideration and quick charging performance consideration are achieved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a pole piece with a novel conductive agent distribution structure and a lithium ion battery comprising the pole piece. Background technique [0002] With the rapid development and wide application of lithium-ion batteries, the requirements for energy density are getting higher and higher; however, with the increase of energy density, the content of electrode active materials must be continuously increased, and the increase of electrode active material content will inevitably lead to conductive agents. The reduction of the ratio will eventually lead to insufficient formation of the conductive network in the pole piece, resulting in an increase in the impedance of the full battery and an increase in polarization, which in turn will cause a series of performance problems. Therefore, under the condition of high energy density, taking into account the battery ...

AI Technical Summary

Problems solved by technology

[0002] With the rapid development and wide application of lithium-ion batteries, the requirements for energy density are getting higher and higher; however, with the increase of energy density, the content of electrode active materials must be continuously increased, and the increase of electrode active material content will inevitably lead to conductive agents. The reduction of the ratio will eventually lead to insufficient formation of the conductive network in the pole piece, resulting in an increase in the impedance of the full battery and an increase in polarization, which in turn will cause a series of performance problems. Therefore, under the condition of high energy density, taking into account the battery The high and low temperature performance becomes more and more difficult

[0003] It has been reported in the prior art to improve the cycle stability of lithium cobalt oxide materials by introducing new coating elements into lithium cobalt oxide, such as on the basis of appropriate coating of Al, Mg, and Ti, and then coating a certain amount of Zr elements performance, while improving the high and low temperature performance of the battery, but the preparation process using this method is not yet mature, and the cost is relatively high

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