Method for describing and evaluating lithium ion battery health state

Abstract

The invention relates to a method for describing and evaluating a lithium ion battery health state and particularly relates to a set of characteristic parameters for evaluating the lithium ion battery health state. As for a traditional method, external parameters such as battery capacity and internal resistance are utilized to describe a health state of a battery, the external result of performance change of the battery is described only through one single aspect. According to the method, a set of character parameters for evaluating the battery health state in the internal physical-chemical aspect of the battery are acquired, the set of parameters have clear physical meaning, describe the internal material and physical-chemical material performance of the battery and can completely describe the comprehensive health performance state, and the brand new method for describing and evaluating the battery health state is realized. Through the method, the internal performance state characteristic parameters for evaluating the battery health state are acquired, performances of different batteries are compared and evaluated, and performance degradation rules of one cell can be further described and analyzed.

Description

technical field [0001] The invention relates to a method for describing and evaluating the health state of lithium-ion batteries, relates to the field of battery technology, and in particular to a method for evaluating characteristic parameters of the health state of lithium-ion batteries. Background technique [0002] Lithium-ion battery is an energy storage element, and its capacity is a key indicator of battery performance. In traditional applications, the percentage of the full charge and discharge capacity of the battery to the rated capacity of the battery is defined as the health state of the battery, which can describe the maximum capacity of the battery. of recession. [0003] In addition, some literatures use the internal resistance of the battery to describe the health status of the battery, including different descriptions such as AC internal resistance and DC internal resistance. The increase in internal resistance is the external manifestation of the increase i...

AI Technical Summary

Problems solved by technology

[0007] The traditional method uses indicators such as the full charge and discharge capacity of the battery and the internal resistance of the battery to describe the state of health of the battery. However, these two parameters do not fully describe the current performance state of the battery.

In terms of full charge and discharge capacity, it is usually the power of the battery at a certain fixed rate, which cannot describe the difference in battery power at different rates; similarly, the internal resistance of the battery used in the traditional method is the internal resistance of the battery in ohms and polarization. It is a comprehensive reflection of resistance under specific discharge conditions, and cannot fully describe the polarization characteristics inside the battery.

Images