Method for correcting SOC (State Of Charge) by utilizing battery charging curve

Abstract

The invention discloses a method for correcting a SOC (State Of Charge) by utilizing a battery charging curve. The SOC is corrected step by step by utilizing the characteristics of a low-end linear interval and a high-end curve point according to the charging curve graphs of a lithium iron phosphate battery at different charging rates. According to the method, the SOC of the lithium iron phosphate battery is corrected by utilizing the low-end linear interval and the high-end full charge point of the charging curve of the battery based on an open-circuit method and an ampere-hour integral method, so that the SOC correcting probability is increased and the SOC estimation precision is improved. The method is easy to implement, popularize and use. As the SOC low-end linear interval correction operation in the charging process is added, the SOC estimation precision in the charging interruption condition can be particularly improved.

Description

technical field [0001] The invention relates to the improvement of the power battery SOC estimation technology. Background technique [0002] The remaining power of the battery, also known as the State of Charge (SOC) of the battery, is one of the important parameters of the battery state, and provides a basis for the control strategy of the electric vehicle. Accurately estimate the remaining power of the current battery, ensure that the SOC is maintained within a reasonable range, and prevent damage to the battery due to overcharge or overdischarge, which provides a technical direction for us to use the battery rationally, improve the service life of the battery, and reduce maintenance costs. How to obtain the battery SOC value accurately and reliably is the most basic and important task of the battery management system. [0003] At present, a lot of research has been done on the accurate estimation of battery SOC at home and abroad. Due to the limitations of the hardware...

AI Technical Summary

Problems solved by technology

The ampere-hour integration method requires high accuracy of current sampling, otherwise a large cumulative error may occur after long-term operation

In addition, the Kalman filter method and the fuzzy neural network method are common. Due to the hardware limitation of the battery management system and the maturity of the algorithm itself, it has not been widely used in practical applications.

[0004] Disadvantages and deficiencies: Lithium iron phosphate battery has a very flat charging and discharging platform, and the SOC of the battery management system requires high precision and real-time online estimation, so the open circuit voltage method is not very suitable for lithium iron phosphate battery

However, electric vehicles require accurate SOC values ​​to be provided at any time, which requires no cumulative error. The current national standard requires that the error should not exceed 8%, and the estimation method of the existing technology is not easy to meet

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