Novel detection method for self-discharge characteristics of lithium iron phosphate system power lithium ion batteries

Abstract

The invention discloses a novel detection method for self-discharge characteristics of lithium iron phosphate system power lithium ion batteries. The method comprises the following steps: step 1, charging and discharging batteries, and adjusting SOC (System On Chip) states of the batteries to be 20-40%; step 2, standing for a certain period of time at normal temperature, and measuring open-circuit voltage (OCV)1 of the batteries; step 3, performing high-temperature aging on the batteries; step 4, standing for a certain period of time at normal temperature, and then detecting OCV2 of the batteries; step 5, calculating a voltage drop deltaU of the batteries, wherein deltaU is equal to OCV1-OCV2; and step 6, calculating an average value and standard deviations of the voltage drops of the same group of batteries, determining a self-discharge detection standard of the batteries, and screening. The method for detecting the self-discharge characteristics of the batteries by virtue of voltage differences of the batteries disclosed by the invention can be used for well shielding interference of factors such as equipment, operations and environment temperature existing in a manufacturing process of the batteries in the self-discharge data acquisition accuracy of the batteries, so that the self-discharge characteristic data distortion of a single battery can be avoided, the matching reliability of the batteries can be effectively improved, and the cycle life of a battery pack can be prolonged.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, and relates to a detection process for the manufacture of lithium iron phosphate power lithium ion batteries, specifically, a new method for detecting the self-discharge characteristics of lithium iron phosphate power lithium ion batteries, including Finally, the SOC state (state of charge) adjustment, voltage measurement, high temperature aging, battery screening and other detection processes are carried out. Background technique [0002] With the continuous development of the global economy, the consumption of energy by human society is increasing day by day, and petrochemical resources are becoming increasingly exhausted. At the same time, problems such as environmental degradation and abnormal climate are intensifying. The development of new energy vehicle technology powered by lithium-ion batteries has become the future energy source of many countries. One of the important strategic dire...

AI Technical Summary

Problems solved by technology

The traditional self-discharge characteristic is to evaluate the self-discharge characteristic level by comparing the capacity attenuation of the battery before and after aging. This method needs to use charging and discharging equipment to charge and discharge the battery before and after aging, which is vulnerable to Affected by various factors such as equipment accuracy, contact conditions of equipment fixtures, operation methods, and ambient temperature during charging and discharging, there is a large deviation in the capacity acquisition conditions before and after aging, which affects the accuracy of data collection

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