Simulation and Comparison of HEV Battery Control for Best Fuel Economy and Longer Battery Life

Boukehili Adel, Zhang Youtong, Sun shuai
2010 World Electric Vehicle Journal  
Almost all HEV battery control strategies keep the battery state of charge (SOC) within a lower limit (SOCmin) (these strategies also called charge sustaining strategies). The goal from sustaining the SOC in this way is to prolong the battery life. But the question is; what is the optimal value of (SOCmin) for a battery, to achieve best fuel economy and longer battery life at the same time?; knowing that when (SOCmin) is too low (around SOCmin=0.2) we get good fuel economy per one speed cycle
more » ... t the battery dies soon and cannot perform a lot of cycles, but when (SOCmin) is high (around SOCmin=0.8) the battery can survive for a larger number of speed cycle but with poor fuel economy per cycle. The objective of this paper is to propose a method to investigate and solve this problem by simulation using Simulink environment; we used the manufacture's data of a Ni-MH battery, empiric equations, and appropriate control strategy to find the optimal value of (SOCmin). The study shows that, for best fuel economy per one cycle; the (SOCmin) value must be as small as possible, for longer battery life; the (SOCmin) value is about (SOCmin=0.85) and for the optimal case (which is the total improvement brought by the battery from first time use until its end of life); the optimal (SOCmin) value is about (SOCmin=0.7).
doi:10.3390/wevj4020421 fatcat:czglfk55fbbojc24yjq3kxwt4u