A kind of liquid injection activation method of power battery

Abstract

The present invention proposes a liquid injection activation method for a power battery, comprising: injecting the electrolyte solution into the power battery for the first time; performing the first activation and charging of the power battery with a first preset current within a first preset time; The power battery is left to stand for a second preset time, wherein the second preset time is greater than the first preset time; the power battery is charged for the second activation, and the second activation charge is pulse constant current and constant voltage charging, wherein the first The charging current of the second activation charging is less than the first preset current, and the charging time of the second activation charging is longer than the first preset time; and the power battery is filled with electrolyte for the second time. The invention can form a stable and dense solid electrolyte interface film on the surface of the positive and negative electrode plate materials of the battery, effectively improves the performance of the iron phosphate power battery, reduces the loss of electro-hydraulic at the same time, improves the working environment of the liquid injection process, and has the advantages of simple operation and safety. Reliable advantages.

Description

technical field [0001] The invention relates to the technical field of lithium batteries, in particular to a liquid injection activation method for power batteries. Background technique [0002] Due to the characteristics of high voltage, high energy density, no memory effect, green and pollution-free, lithium-ion secondary power batteries have been widely used in electric tools and electric vehicles in recent years. [0003] In the production process of lithium-ion secondary power batteries, battery cell injection and activation is a very important process operation. After the power battery is assembled, the battery is injected with electrolyte, and the battery is charged and activated after the liquid injection, and then pulled out The generated gas is vacuum-sealed, and the liquid injection is to inject the electrolyte into the battery. The electrolyte fully infiltrates the battery diaphragm, positive and negative electrode materials, and serves as the lithium ion current...

AI Technical Summary

Problems solved by technology

[0004] At present, the lithium iron phosphate battery adopts the method of precharging with a small current after one-time liquid injection is completed. The traditional method of one-time liquid injection and one-time filling of the electro-hydraulic will cause the electro-hydraulic to pass through the injection during the manufacturing process. The liquid hole is in contact with the air for a long time, and the moisture in the air is absorbed into the electrolytic solution. The moisture will cause the electrolyte salt in the electrolytic solution to decompose and produce hydrogen fluoride (HF), which will react with the positive and negative electrode materials of the battery plate and damage the SEI formed during the activation process. membrane, which deteriorates the performance of the battery and damages the service life of the battery. At the same time, if too much electrolyte is filled at one time, it will be taken out by the gas generated during the early activation process, resulting in waste of electrolyte and increased manufacturing costs. The HF acid volatilizes in the air, which is harmful to the health of operators

At the same time, the SEI film formed by long-term low-current and constant-current charging will have poor stability during the subsequent use of the power battery, and the consistency of the batteries produced in large quantities will not be high, resulting in the power density and energy density of the vehicle power battery being in the process of recycling. The attenuation is too fast, and at the same time, the unstable SEI film will react repeatedly with the positive and negative materials of the battery during recycling, causing the decomposition of organic components in the electro-hydraulic and generating gas at the same time, causing the internal pressure of the battery to rise, the battery bulging, and Batteries continue to use buried safety hazards

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