Safe lithium ion battery

Abstract

The invention creatively provides a safe lithium ion battery. The outer surface of a negative current collector on the outermost layer in a battery cell of the battery is coated with a molecular sievecoating, and the molecular sieve coating comprises the following components in percentage by weight: 70-90% of a molecular sieve, 10-30% of a conductive agent and 10-20% of a binder. According to thelithium ion battery provided by the invention, the outer surface of a negative plate on the outermost layer of the battery cell is coated with the molecular sieve coating for selective adsorption, and the molecular sieve coating is arranged on the surface, far away from the positive plate side, of a first negative plate which does not participate in the chemical reaction of the battery, so that the electrochemical performance of the battery cell is not reduced, gas generated by the battery cell can be effectively adsorbed, and the safety performance of the battery cell is obviously improved.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, and in particular relates to a safe lithium ion battery. Background technique [0002] With the continuous innovation of new energy material research and development technology, lithium-ion batteries with advantages such as low-carbon environmental protection, high energy density, and wide operating temperature range have received widespread attention. In recent years, coupled with the vigorous promotion of national policies, the lithium-ion battery industry has gradually become the main force in the electric vehicle energy storage market. Therefore, the market has put forward requirements for lithium batteries with higher energy density, higher cruising range, and higher power density. However, the safety performance of batteries with high energy density has been greatly reduced, and fire accidents of new energy electric vehicles on the market are common. This requires us to improve the sa...

AI Technical Summary

Problems solved by technology

However, this technology also has the risk of large internal resistance of the diaphragm and high self-discharge, which affects the transmission of lithium ions. At the same time, when the battery produces a large amount of gas, it cannot avoid further disadvantages of thermal runaway.

[0006] There are also some technologies aimed at the gas production of batteries, adding oxygen absorbing additives to the positive electrode material. When the positive electrode active material decomposes at high temperature and releases oxygen, it can quickly capture the surrounding oxygen and reduce the internal oxygen concentration when the lithium battery is thermally runaway. Lithium batteries cannot meet the fire conditions and avoid thermal runaway of lithium batteries, but this method reduces the effective active material area of ​​the battery cell and reduces the energy density of the battery cell

The main purpose of the molecular sieve disclosed in the patent application "An Internal Oxygen Self-Absorption Safe Lithium Battery" with the application number CN201810712193 is to absorb the oxygen generated in the cell, and this patent is to mix the oxygen absorber with the positive electrode material. This mixing not only It will cause a decrease in the energy density of the battery cell, increase the complexity of the mixing process, and cause a decrease in the electrical performance of the battery cell, such as high-temperature storage performance, rate performance, high and low temperature performance, etc.

Images