Three-point type screening method for quick charging/discharging lithium ion battery

Abstract

Provided is a three-point type screening method for quick charging / discharging lithium ion batteries. Charging and discharging circulation is conducted on batteries once at low multiplying power, at high multiplying power and at medium multiplying power respectively. Set matching is conducted on the batteries by taking the difference between measured capacitance and an average value, the difference between a measured open-circuit voltage and an average value, the difference between measured DC internal resistance and an average value and the difference between a constant current ratio and an average value as standards. To be specific, 0.2C is taken as a low current, the maximum current utilized by an electrical core is taken as a high current, and (the low current + the high current) / 2+ / -50% is taken as a medium current to carry out charging and discharging circulation. The method improves the safety, reliability and cycle service life of utilization of the quick charging / discharging lithium ion batteries, ensures consistency of battery states of the quick charging / discharging batteries in different charging and discharging rates during a charging and discharging process, and can be applied to screening of lithium ion batteries of various types, systems and specifications.

Description

technical field [0001] The invention relates to a technology in the field of lithium-ion battery detection, in particular to a screening method based on fast charging / discharging lithium-ion batteries. Background technique [0002] Due to raw materials, production environment, production process and other reasons, lithium-ion batteries will have inconsistencies. The traditional lithium-ion battery screening method is usually to screen capacity, voltage and resistance at a small current. If it is under low current, the electrochemical reaction in the battery can be considered as a quasi-static process, and it is not a big problem when such a battery is screened and matched. However, in the case of high current, the degree of electrochemical reaction inside the battery will be intensified. In addition, if the difference in internal resistance is 10 times or even 25 times higher than the current, there will be a thermal effect of 100 to 625 times. The resulting temperature ch...

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Problems solved by technology

[0003] The present invention aims at the fact that the screening method for lithium-ion batteries in the prior art cannot effectively test the actual performance and state of the lithium-ion battery in the process of charging and discharging with a large current, and there are certain differences in the attenuation and aging degree of the single battery itself, and by This leads to the technical problems of poor safety, reliability and service life of the assembled battery pack. A screening method based on fast charging / discharging lithium-ion batteries is proposed, combining the cell capacity under low rate, medium rate and high rate conditions. , voltage, internal resistance, and constant current charging ratio consistency changes, and the consistency of battery AC resistance under different states of charge after shelving is used to screen and match batteries. Safety, reliability and cycle life of use

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