Development of predictive techniques for determination of remaining life for lead acid batteries under fast charge

Recent studies have demonstrated that fast charging techniques can significantly extend the effective daily range of lead acid battery powered EVs. A research team composed of Arizona Public Service (APS), CSIRO Division of Minerals (CSIRO), Electric Transportation Applications (ETA), and Hawker Energy Products, Incorporated (HEPi) has been assembled to conduct a detailed laboratory and field program to develop operating regimes that will both extend vehicle daily range and improve lead acid battery life in EV applications using fast charge. Research is being conducted under the cognizance of the Advanced Lead Acid Battery Consortium, both in the laboratories of CSIRO and HEPi, and in the electric vehicle fleet of APS and ETA. As the life of batteries under field testing in electric vehicle fleets has been extended using fast charge to as many as 600 cycles, the time to complete field tests has increased dramatically. In order to reduce the time required to evaluate various charge algorithms in field testing, the research team has developed a technique to predict the life remaining in Hawker Genesis ^(R) lead acid batteries. This technique allows the research team to test various charge protocols by field testing for a representative number of cycles, then analyzing the remaining life in the battery, pack for comparison against other charge protocols. The predictive technique is a correlation of positive grid corrosion versus battery life for the Hawker Genesis^(R) battery. This paper details the results of this field testing and presents data to substantiate the use of percent positive grid corrosion as an estimate of life remaining in Hawker Genesis^(R) lead acid batteries