Method for detecting internal states of lithium ion batteries and nondestructively screening lithium ion batteries

Abstract

The invention relates to the technical field of manufacturing of lithium ion batteries, in particular to a method for detecting the internal states of the lithium ion batteries and nondestructively screening the lithium ion batteries. The method comprises the following steps that: the lithium ion batteries are put into formation equipment, and the formation charging process of the lithium ion batteries is divided into a constant current charging stage and a constant voltage charging stage; a current signal is given at the constant current charging stage, the acquired voltage response signal continuously rises according to a certain law, the rising velocity of voltage is continuously increased, and the internal states of the batteries are abnormal if the rising velocity of a voltage curve is continuously abnormal in the process; and a voltage signal is given at the constant voltage charging stage, the acquired current response signal curve continuously falls according to a certain law, the falling velocity is gradually reduced, and the internal states of the batteries are abnormal if the falling velocity of the current curve is abnormal in the process. The method has the advantages that on the one hand, screening accuracy is high, and defective products are prevented from entering the next process; and on the other hand, the problems in the previous production process can be timely fed back and guided in being rectified.

Description

technical field [0001] The invention relates to the technical field of lithium-ion battery manufacturing, in particular to a method for detecting the internal state of a lithium-ion battery and non-destructive screening. Background technique [0002] With the global energy crisis and environmental pollution becoming more and more serious, the search for green and sustainable new energy has become the main development direction of the energy field. As an energy-saving and environmentally friendly new energy vehicle, electric vehicles are developing rapidly. Lithium-ion batteries have become one of the power sources that have attracted much attention due to their advantages such as high energy density, long cycle life, green and pollution-free. However, the safety of large-capacity lithium-ion batteries has always been one of the main problems restricting its development. Under abuse conditions, such as high temperature, internal short circuit, extrusion, vibration, etc., the ...

AI Technical Summary

Problems solved by technology

In fact, in the battery manufacturing process, it is easy to have insufficient liquid injection, battery leakage, lithium precipitation inside the battery, electrode strip connection, broken strip and other abnormal phenomena. Some of these abnormal batteries can be found in the later performance and appearance inspection. Some are difficult to reflect from the appearance of the battery and the performance data that can be screened. It is easy to mix into normal batteries and enter the normal use stage, which has great potential safety hazards.

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