Performance Survey for Li-Ion Battery in a Hybrid Vehicle with 105,000 Km Driving

A global technical regulation for vehicle environmental performance such as exhaust gases, fuel economy and range has appeared in the issue of WP29 in the United Nations Economic Commission for Europe (UN-ECE). [1] One of major concerns is that battery degradation may influence on the fuel economy deterioration of electrified vehicles such as HEVs. However, numbers of report from automakers about the relation between a fuel economy change and battery performance change are limited. In this paper, we demonstrate the battery performance change in a hybrid vehicle with 105,000 km driving and its fuel economy change. Fuel consumptions of the hybrid vehicle with 1.5 L gasoline engine and 105,000 km driving were compared before and after battery pack replacement. The type of the battery was Lithium-ion. The fuel consumptions with the “state of charge correction” were measured by a chassis dynamometer with Japanese driving test cycle of “JC08 mode” (Fig.1). Before replacing the battery pack, the hybrid vehicle ran with a fuel consumption of 29.24 km/L. Then after replacing the battery ran with a fuel consumption of 29.96 km/L. After the fuel consumption test, the battery pack with 105,000 km driving was disassembled to battery cells. Discharge capacities and internal resistances of the cells were measured. We will discuss the battery performance change and its influence on the fuel consumption rates of the vehicles. [1]https://www.unece.org/trans/main/wp29/introduction.html Figure 1