Assessing the potential of an electric vehicle hybrid battery system comprising solid-state lithium metal polymer high energy and lithium-ion high power batteries

In this work the characterization and application of a prototype solid-state lithium metal battery for an electric vehicle application is addressed. This mid-temperature battery is operated at a temperature of 80 °C. In an innovative approach, this high energy technology is integrated into a hybrid battery system, where it is supported by a highest power lithium-titanate technology. Three hybrid battery system configurations are systematically derived for a high class vehicle with different performance requirements. On the basis of an overall vehicle simulation model, comprising a thermal model of the lithium metal polymer battery pack, the performance of the system is evaluated under regular and extreme driving conditions. The results indicate that battery hybridization makes a reasonable utilization of the lithium metal polymer battery in an electric vehicle possible. The power capability of the overall battery system in discharge as well as charge direction is significantly increased. Moreover, the system allows for a wider utilization of overall battery system's energy, resulting in an increase of drivable distance. Furthermore, additional functionalities of the hybrid battery system are discussed, such as warm-up procedure, low temperature performance enhancement and redundancy.