Design of Controlled Charging Strategy for Parallel Operation of Multiple Modular Lithium-ion Battery Packs

A recent trend in electric vehicles has been to utilize larger battery capacity to provide a higher driving range. The conventional battery pack connection employed a single battery pack to provide sufficient voltage and capacity requirements for the system. But, with the increasing demand for higher energy capacity within the limited space constraint and given thermal management issues of the large single battery pack, the scope for battery pack connection architecture of different battery modules connected in parallel to increase the energy capacity has been growing in the electric vehicles. However, the parallel modular connection presents problems as it is susceptible to differences within the modules. Furthermore, the arrangement of lithium-ion battery packs in parallel modular architecture dramatically increases the complexity of the controller as well as the cost of implementation. An adequately engineered parallel modular battery pack system can improve overall reliability and safety. This paper uses a voltage-controlled bidirectional controller to mitigate the problems associated with the parallel connection with minimized complexity. As claimed by the results of the simulated controlled parallel modular battery pack system in this paper, a reliable, efficient, and easily implementable system has been obtained.