State-of-health estimation method for power-type power battery

Abstract

The invention discloses a state-of-health estimation method for a power-type power battery. The method comprises the steps: selecting a battery remaining capacity (SOC) value with the highest occurrence frequency as a reference value according to a vehicle driving condition; when the SOC value reaches a first reference value, starting to integrate and accumulate the discharge energy and the charge energy of the battery, and stopping energy accumulation when the SOC value reaches a last reference value in a time window range, wherein at the moment, the charge and discharge energy efficiency eta is equal to discharge energy / charge energy * 100%; performing fitting to obtain a battery charging and discharging efficiency curve according to the measured battery charging and discharging efficiency; evaluating the state-of-health of the battery through the charging and discharging efficiency of the battery, and estimating the state-of-health of the battery on line according to the fitted charging and discharging efficiency curve of the battery. The internal resistance increasing trend of the battery is estimated through the charging and discharging efficiency of the battery, then the state-of-health of the battery is estimated. The method is easy and convenient to calculate, high in operability, accurate in estimation result and free of complex logic architecture.

Description

technical field [0001] The invention belongs to the field of electric vehicle power battery management, and in particular relates to a method for estimating the state of health of a power type power battery. Background technique [0002] An electric vehicle is a means of transportation with an electric motor as the power device and a battery as the energy storage device. The development of electric vehicles is an emerging strategic industry that countries have vigorously developed after the energy crisis and financial crisis. Therefore, battery management is extremely important. The health of the power battery is a measure of the life of a battery in a specific environment. For users, the health of the battery can be used as an important basis for battery maintenance, repair, and replacement. [0003] The health status of power batteries is generally measured by capacity and internal resistance. For batteries, the health status is optimal when leaving the factory, and its ...

AI Technical Summary

Problems solved by technology

At the same time, considering that the ohmic internal resistance of the battery is closely related to the temperature of the battery pack, the current rate, and the state of charge of the battery, a method of screening internal resistance at preset time intervals is introduced, and the relationship between the screened average internal resistance and the state of health SOH is established. , using the internal resistance characteristics of the battery to accurately reflect the current state of health of the battery, but this method is more complicated to calculate

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