Lithium ion battery and preparation method thereof

Abstract

The invention discloses a lithium ion battery and a preparation method thereof. The lithium ion battery comprises a current collector, an active substance layer, a ceramic layer and a polymer microsphere particle layer. The active substance layer is formed on at least part of the surface of the current collector, the ceramic layer is formed on at least part of the surface of the active substance layer away from the current collector, and the polymer microsphere particle layer is formed on at least part of the surface, away from the active substance layer, of the ceramic layer. According to thelithium ion battery, the pole piece coated with the ceramic layer and the polymer microsphere particle layer is adopted, so that the wettability of electrolyte to the pole piece can be effectively improved, thermal shutdown is realized at high temperature, and the overcharge, needling and heating safety performance of the battery is effectively improved.

Description

technical field [0001] The invention relates to the field of electrochemical energy storage equipment, in particular, the invention relates to a lithium ion battery and a preparation method thereof. Background technique [0002] With the increasing energy crisis and environmental pollution, human beings are faced with the severe challenge of developing green and renewable energy. Lithium-ion batteries have attracted much attention due to their advantages such as high energy density, no memory effect, low self-discharge rate, long cycle life, and clean and pollution-free. The development of electric vehicles powered by lithium-ion batteries has become the focus of global attention. [0003] The performance of the power battery is the limiting factor that determines the development of electric vehicles. Although the power battery has achieved rapid development in some aspects of performance, the safety performance cannot be effectively guaranteed. In extreme cases such as sh...

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Problems solved by technology

[0003] The performance of the power battery is the limiting factor that determines the development of electric vehicles. Although the power battery has achieved rapid development in some aspects of performance, the safety performance cannot be effectively guaranteed. In extreme cases such as short circuits, accidents such as fires and explosions may occur due to thermal runaway. Improving the safety performance of power batteries is already an arduous task.

[0004] Chinese patent CN107768710A discloses a high-safety lithium-ion battery without a diaphragm. The invention realizes the preparation of a lithium-ion battery without a diaphragm by coating a layer of organic polymer particles on the surface of the positive and negative electrodes. It has certain advantages in safety performance such as heating, but due to the weak absorption capacity of the organic coating electrolyte, it affects the wettability and electrochemical performance of the lithium-ion battery, and the strength of the organic coating is worse than that of the ceramic coating. In the process of pressing, it is easy to cause defects such as crushing and short circuit

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