Estimate SOC Capacity of Power Battery on the Dynamic Working Voltage

This paper takes the VRLA battery cell as the research object, to solve real-time estimation problem of the electric vehicle power battery´s state of charge(SOC) in working status, proposes a new estimation method. Through the measurement of a periodic constant current load´s work battery, get a series of working voltage, using phase-slope calculation method based on the working voltage at this time, calculating the battery´s time remaining and SOC. This method proved the feasibility of the dynamic working point can be mapped to the static working point, and the largest relative error is no more than 7%. Through the software implementation can compensate temperature, aging and other interference factors. Error analysis results show that this method has small error, high measurement precision.