Battery cell, battery pole piece and preparation method thereof, battery

Abstract

The invention relates to a battery cell, a battery pole piece and a preparation method thereof, and a battery, wherein the battery cell includes two first negative pole pieces located on the outside, and a positive pole piece located between the two first negative pole pieces. sheet, and a diaphragm between the first negative electrode sheet and the positive electrode sheet; the first negative electrode sheet includes a first negative electrode current collector, a negative electrode disposed on a surface of the first negative electrode current collector active material coating, and a flame retardant coating on the other surface of the first negative electrode collector, the negative active material coating on each of the first negative electrode sheets is opposite to the positive electrode sheet ; Wherein, the raw materials of the flame retardant coating include flame retardants, anti-settling agents, adhesives and surfactants. The present invention can improve the safety performance of the battery by applying a flame-retardant coating on the first negative pole piece, and the flame-retardant layer is located at the outermost side of the battery cell, without affecting the internal resistance, rate, cycle and other electrochemical properties of the battery.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a battery cell, a battery pole piece, a preparation method thereof, and a battery. Background technique [0002] In recent years, with the rapid development of portable electronic products, electric vehicles, and energy storage power stations, lithium-ion batteries have become the preferred chemical power sources due to their high energy density, high operating voltage, small self-discharge, and long cycle life. With the upgrading of products, people have higher and higher requirements for the energy density of lithium-ion batteries, but the safety performance has not been upgraded simultaneously. In actual use, safety accidents occur from time to time, mainly because lithium-ion batteries are exposed to high The contraction and embrittlement of the diaphragm during the process of falling, falling, etc. lead to thermal runaway, such as contact short circuit between cathode and ...

AI Technical Summary

Problems solved by technology

However, this approach often sacrifices the electrochemical performance of the battery and cannot fundamentally solve the problem.

There are also some technologies that divide the battery current collector into two areas, one of which is coated with an active material coating, and the other area is coated with a PTC material coating. The resistivity of the material increases rapidly, thereby blocking the transmission of electrolyte ions, or directly blocking the circuit, thereby protecting the battery system and improving the safety performance of the battery. Although this method prevents the temperature of the battery from changing to a certain extent Further increase, but it will easily lead to an increase in the internal resistance of the battery, a decrease in the energy density of the battery, etc., which will have a great impact on the performance of the battery

There are also some technologies that wrap the flame retardant in microcapsules, mix them with a solution containing a separator protective agent and coat them on the surface of the separator, and finally fix the microcapsules on the surface of the separator. When the battery thermal runaway occurs, release the resistance The fuel protects the battery, but this method will increase the internal resistance of the separator, affect the transmission of lithium ions, and adversely affect the rate performance and low temperature performance of the battery

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