After an extensive set of battery cell performance testing on four different types of battery cells of different chemistries in WP2, WP3 has performed their battery configuration optimization. This way an optimal configuration of a hybrid battery pack has been defined, combining two types of battery cells into one Hybrid Battery Energy Storage System (HBESS). This HBESS configuration includes optimized power electronics and an Energy Management System (EMS).
Current activities in WP2 (close collaboration between CEGASA, CEA and TNO) entail the development of BMS algorithms, battery cell testing (performance and ageing) on the two selected battery types and the design of the final battery stacks (each stack containing one type of battery cell, combined into the full HBESS). Making use of the generate test data, various algorithms are under development that support the control of the HBESS by both the BMS and the overarching EMS. The key algorithms will be advanced SoC and SoH estimation algorithms, coupled to a novel Active Diagnostics Protocol (ADP) providing monthly updates of battery model parameters. Additionally, developments of a Battery Passport (to store and track relevant metrics) and a Remaining Useful Life (RUL) algorithm are ongoing in parallel.
Regarding the design of the battery stacks and the HBESS, investigations have been performed to find a suitable thermal design by implementing Phase Change Material (PCM) in the design of one of the battery stacks. That led to a subset of potential materials and constructions, out of which the most promising ones are now being tested at a small scale. This will in turn provide input for the design of the final battery stacks.
As the EMS being developed in WP4 has the optimization of the lifetime of the battery as one of its key objectives, WP2 will also develop an ageing cost function based on the currently running battery ageing tests. The first preliminary results of the ageing testing of one type of cell can be seen in the first picture below, showing the measured capacity degradation under various conditions.
The first preliminary results of the ageing testing of one type of cell