A combined estimation method for the state of charge and the state of health of lithium ion batteries

Abstract

The invention provides a combined estimation method for the state of charge and the state of health of lithium ion batteries. The method comprises the steps of: firstly, carrying out constant current charging-discharging experiments at the temperature of 25 DEG C based on 1 / 3 C for a fresh-from-the-factory lithium ion battery to obtain the initial rated capacity C0 of the battery; secondly, determining whether the battery works in charge and discharge states at each sampling instant according to the magnitude of sampling current i; thirdly, a circulation mode is started; fourthly, a storage mode is started; fifthly, judging whether the SOH of the battery is less than 80%, determining that the battery reaches the end of lifetime and terminating the circulation if the SOH is less than 80%, and determining that the battery is in the state of health and returning to the second step if the SOH is not less than 80%. The invention provides a method for combined estimation of the SOC and the SOH of batteries in a multi-scale frame. The method takes the SOH change in the storage process and the reuse process of lithium ion batteries into consideration, and the calculation quantities of the SOC and SOH estimation algorithms are reduced, so that the estimation accuracy is improved.

Description

technical field [0001] The invention relates to a method for jointly estimating the state of charge and the state of health of a battery, in particular to a method for jointly estimating the state of charge and the state of health of a lithium ion battery. Background technique [0002] At present, as the main energy source of pure electric vehicles, the performance of lithium-ion power batteries has a very important impact on the power, cruising range and economy of electric vehicles. The battery management system is the core component of electric vehicles, which mainly includes functions such as data collection, condition monitoring, health management, safety management and balance management. The main states monitored by the battery management system include state of charge (State of Charge, SOC) and state of health (State of Health, SOH). The monitoring of battery status can provide a basis for the study of electric vehicle safety management strategies, health management...

AI Technical Summary

Problems solved by technology

[0011] The purpose of the present invention is to solve the problems of separate design of estimators, low estimation accuracy and high resource occupation in the existing methods for estimating the state of charge and state of health of batteries, and provides a combined state of charge and state of health of lithium-ion batteries. Estimation method

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