Modular BESS Architecture for Enhanced Performance and Extended Lifetime

This paper evaluates and compares the performances of non-modular and modular battery systems. The modular architecture consists of several battery modules that are individually controlled by means of their corresponding power converter. For the analysis, a realistic case study was considered, which involved a residential complex with electric vehicle chargers. Simulations were performed integrating a battery ageing prediction model. In this way, the available energy and capacity loss of the proposed system architectures were quantified under module-to-module capacity discrepancies. The capacity loss to available energy ratio was used as key performance indicator. The results demonstrate energy availability and lifetime reduction issues related to the weakest cell problem in the conventional non-modular battery. In general, the modular architecture minimises inhomogeneity effects and exhibits improved performance. Therefore, the higher cost linked to the extra power converters is expected to be compensated in large-scale applications, where the cost of the battery outweighs that of the power conversion systems.