Method for screening lithium ion batteries

Abstract

Provided is a method for screening lithium ion batteries. When constant-current constant-voltage formation is carried out on aged cells, constant-current charging time needed by each cell from first cut-off voltage charging to second cut-off voltage charging is recorded; a plurality of cells are selected as samples, open-circuit voltage of each cell sample after formation is recorded, and a fitting formula v=at+b is obtained according to the corresponding relation between the constant-current charging time and the open-circuit voltage after formation of each cell sample; a constant-current time node is calculated out through standard cell voltage according to the fitting formula, and the constant-current time node serves as the standard for judging whether the voltage of the corresponding cell is not good; and if the constant-current charging time of each cell is smaller than or equal to the corresponding constant-current time node, the fact that the cell is a bad-voltage product is determined, and if the constant-current charging time of each cell is larger than the corresponding constant-current time node, the fact that the cell is a good-voltage product is determined. By means of the method, defective products of the lithium ion batteries can be screened rapidly and accurately, efficiency is high, and cost is low.

Description

technical field [0001] The invention belongs to the technical field of polymer lithium-ion batteries, and in particular relates to a method for screening batteries with poor voltage after formation of lithium-ion batteries. Background technique [0002] With the rapid development of modern society, people's requirements for the quality of life are getting higher and higher. Electronic products represented by mobile phones and tablet computers are more and more popular among people, and products with low prices and high cost performance are even more popular. Admired by the market. How to reduce costs as much as possible has become a major problem for enterprises today. Lithium batteries, one of the core components of electronic products, are also troubled by this. How to reduce costs and improve production efficiency has become a key factor to stand out in the fierce market competition. [0003] In the existing lithium-ion battery manufacturing process, the lithium-ion bat...

AI Technical Summary

Problems solved by technology

At present, the most commonly used method is to test the battery cell with a voltmeter after formation, and pick out defective products with low voltage.

This method mainly uses manual measurement, which not only increases manpower and material resources, increases production costs, but cannot improve production efficiency, but also increases the number of times the battery is manually handed over, indirectly increasing the risk of battery damage.

[0004] In addition, in the prior art, there is also a battery for screening defective products by charging and discharging the battery and testing the capacity of the battery after the cycle, such as the Chinese invention patent with the patent number 201310445622.0 and the Chinese invention patent with the patent number 201310199605.3 And the Chinese invention patent application with the patent application number 201210488606.5, but when using these screening methods, it is necessary to charge the battery cells, and then discharge them, and then test to obtain the discharge capacity. The time is long, the process is complicated, and the cost of manpower and material resources is increased. not conducive to production operations

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