Development of a new battery management system with an independent balance module for electrical motorcycles

Abstract

Conventional balance modules are integrated with the battery management system (BMS) and occupy a large area of the BMS system. In addition large balance currents generate high heating rates and require heat dissipation mechanisms. This study proposes an independent structure for the balance module. Specifically the balance module is removed from of the BMS and is integrated with an off board charger. A new BMS structure is therefore created with a simplified BMS inside the battery module and the heat dissipation requirement for the balance module could be easily met on the charger side. The design, fabrication and test of this new type of BMS on a 72 V heavy electric motorcycle application is detailed in the current work. The new BMS reduces the space and weight required for the BMS in the e-motorcycle. Complexity in the battery module or on the EV side is significantly reduced. The heat dissipation problem associated with the large balance current is also resolved by moving the balance module to the charger end.