Effects of Battery Charge Acceptance and Battery Aging in Complete Vehicle Energy Management

Abstract

In this paper, we propose a solution to the complete vehicle energy management problem with battery charge acceptance limitations and battery aging limitations. The problem is solved using distributed optimization for a case study of a hybrid heavy-duty vehicle, equipped with a refrigerated semi-trailer for two different battery models. The first battery model takes charge acceptance into account by adding an additional energy state to the optimization problem. The second battery model includes battery aging for which a novel iterative algorithm is proposed. Simulation results show that charge acceptance limitations only have a minor effect on the solution to the energy management problem, while battery aging leads to a trade-off between battery capacity loss and fuel consumption reduction. In particular, a decrease in capacity loss by 260%, leads to a drop in fuel consumption reduction from 9.40% (without battery aging) to 8.61% (with battery aging), both when compared to a conventional vehicle. This is caused by the fact that aging limitations cause less energy to be stored in the high-voltage battery. Still, because energy can also be stored in the refrigerated semi-trailer, smart control of this refrigerated semi-trailer leads to an additional fuel reduction 0.53% in the case where battery aging is incorporated, while it was only 0.09% when battery aging was not considered. In other words, the drop in the fuel consumption reduction caused by battery aging constraints can be partly compensated by smart control of other energy buffers, which shows the true benefit of complete vehicle energy management.