Remaining Capacity Estimation Of Battery Based On Multi-parameter Analysis

In order to ensure the operation of emergency power supply in the emergency state safe and reliable,the battery as the guarantee of its emergency power supply,monitored remaining capacity is particularly important.Since the estimation accuracy of battery remaining capacity is based on the accurate estimation of battery state parameters,and the state parameters include the battery discharge rate,State of Health(SOH),the characteristic relationship between State of Charge(SOC)and Open Circuit Voltage(OCV),etc.,this paper focuses on several state parameters to realize the estimation of battery remaining capacity.In the process of realizing the estimation of the remaining capacity of the battery,this paper mainly completes the following work:(1)This paper uses the ampere-hour integral method as the principle of battery remaining capacity estimation to establish a mathematical model to estimate the remaining capacity of the battery based on the multiple compensation factors such as the battery SOH,discharge rate and the relationship between the characteristics of the dynamic maintenance SOC-OCV.(2)The accurate estimation of the remaining capacity of the battery should be based on the explicit actual full capacity,so the paper adopts the sequential estimation of SOH of the battery to realize the correction of the actual full capacity of the battery Qualitative estimation,that is,the AC injection method combined with the phase difference measurement algorithm based on the principle of signal correlation to complete the measurement of the AC internal resistance of the battery,to achieve the qualitative estimation of the battery SOH.The quantitative estimation is realized in the periodic maintenance stage of the standby battery pack.That is to say,by analyzing the relationship between the SOC value and SOH value of the battery model parameters after maintenance and discharge,the relationship between the ohmic internal resistance and SOH after regular discharge maintenance(20% of the rated capacity)of the battery is established,and finally the quantitative estimation of the battery health state is realized.The results showed that the sequential estimation of battery SOH could ensure the predictability and accuracy of battery health monitoring,and the deviation between the SOH value obtained by quantitative estimation and the actual value was about 3%.(3)Although the improved ampere-hour integral method with discharge rate and state of health factor can ensure the accuracy of remaining capacity estimation to some extent,in order to solve the integral accumulation error caused by current sampling error in the process of battery remaining capacity estimation,a multi-parameter joint estimation method of battery remaining capacity was proposed.The joint estimation method refers to the improved ampere-hour integration method combined with the dynamic maintenance of the SOC-OCV characteristic relationship to eliminate the cumulative error when the remaining capacity is a fixed proportion of actual full capacity.The simulation results show that the method used in this paper can eliminate the integral accumulation error and improve the estimation accuracy of the battery remaining capacity.In this paper,on the basis of the improved ampere-hour integral method with the influence factors such as discharge rate and SOH,the remaining capacity of the battery is estimated by combining the dynamic maintenance of the SOC-OCV curve.The maximum estimate error is about 2.5%.It can predict the actual use of the battery,to avoid battery abuse.