Estimating method of charge state of power battery

Abstract

The invention relates to an estimating method of the charge state of a power battery. The estimating method is characterized by including the following steps: estimating system on chip (SOC) initial value of the battery according to last charge-discharge state of the battery and SOC value and standing time of the battery since last-time use comprehensively, calculating battery inner resistance and polarization voltage of the battery, collecting working current and voltage at two ends of the battery in real time, estimating SOC of the battery according to the SOC comprehensive estimation algorithm based on an expansion Kalman filtering method and an ampere-hour metering method, storing the SOC of the battery and the corresponding working current and voltage at two ends of the battery, storing current time, battery SOC and battery charge-discharge state before the system is closed down and closing the system down. The estimating method has the advantages of being small in SOC initial value, simple in algorithm, small in metering quantity and high in accuracy.

Description

technical field [0001] The invention relates to a method for estimating the state of charge of a battery, in particular to a method for estimating the state of charge of a power battery for an electric vehicle. Background technique [0002] The state of charge (SOC-State Of Charge) of the battery is one of the important parameters reflecting the performance of the battery, and it provides an important basis for the management and maintenance of the battery pack. For electric vehicle drivers, the SOC of the battery is like the fuel gauge of an ordinary car. Only by knowing the current SOC of the battery accurately can the driving range of the car be judged. However, due to the highly nonlinear nature of the battery, there are many factors affecting the SOC of the battery, and estimating the SOC of the battery is far more complicated than calculating the amount of fuel. [0003] In theory, the SOC of the battery is defined as the current remaining battery capacity Q of the ba...

AI Technical Summary

Problems solved by technology

[0005] (1) The initial SOC of the battery cannot be calculated;

[0006] (2) There are cumulative errors, and the accuracy requirements for the current detection system are relatively high;

[0011] Based on the query of the retrieved patent materials, it is found that the main problem of various battery state-of-charge estimation methods is that the initial SOC estimation algorithm of the battery is single, and the error is relatively large; the whole algorithm either guarantees the accuracy but is too complicated, or the algorithm is simple but The accuracy cannot be guaranteed, and there is no algorithm that combines algorithm complexity and algorithm accuracy

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