Power battery charge state estimation method and system

Abstract

The invention discloses a power battery charge state estimation method and system. The method comprises the steps: building equivalent models for all kinds of power batteries based on laboratory environments and a standard battery second-order model, and fitting battery parameters; building a state-space equation of a battery output-input linear system according to the equivalent models; setting the initial SOC estimated value when a practical power battery system is started, determining the corresponding battery parameters according to the types of batteries in the practical power battery system, and setting a noise weight function needed by running of an H(infinity) filtering algorithm; and starting the running of the power battery system after the parameters are set, in the running process, collecting values of voltage, current and temperature of each battery at each sampling moment in real time, substituting the collected values of voltage, current and temperature of each battery at each sampling moment into the state-space equation and the noise weight function, and calculating to obtain the SOC estimated value at each moment in real time by adopting the H(infinity) filtering algorithm. According to the method, any assumption on outside noise is not required, so that the estimated accuracy is obviously improved, and the antijamming capability is greatly improved.

Description

technical field [0001] The invention relates to the field of batteries, in particular to a method and system for estimating the state of charge of a power battery. Background technique [0002] The battery management system is an important part of ensuring the safe and stable driving of electric vehicles, and the state of charge (SOC) estimation of the battery is the core of the battery management system, and it is also the basis for realizing battery charge and discharge management and load balancing . However, the high nonlinearity of the battery makes its SOC easily affected by many factors, making it very difficult to accurately estimate the SOC. [0003] At present, the commonly used SOC estimation methods include the open circuit voltage method, the ampere-hour integral method, and the extended Kalman filter method. [0004] The open circuit voltage method utilizes the fixed nonlinear relationship between the open circuit voltage (OCV) of the battery and the SOC of t...

AI Technical Summary

Problems solved by technology

The main problems of this method are: (1) if the battery is not sufficiently static during the measurement, the polarization effect of the battery will cause a large deviation between the electromotive force and the open circuit voltage, which will affect the measurement accuracy; (2) if Standing for a long time, it is obviously unable to meet the needs of real-time performance

This algorithm has high requirements on the battery model, and at the same time makes too ideal assumptions about the external environment, which makes it difficult to handle the noise with bias well, and it is also easy to cause the accumulation of noise under certain circumstances, which weakens the SOC estimation. anti-interference ability

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