Operational experience and system modelling of Dual Chemistry Energy Storage Systems

Energy storage is predicted to play an increasing role in next-generation energy systems as countries move towards a renewable future.  From transport electrification to grid-connected projects, a wide range of applications and technologies are currently available on the market or in the research and development stage.  One such area is hybrid storage systems which use technologies with different operational characteristics to obtain an overall improved storage performance.  The first part of this presentation presents the operational history and general performance data for a dual-chemistry energy storage system.  The ADEPT system is a 100kW grid-connected hybrid battery system which uses lead–acid and Li-ion in the same unit connected directly on the DC bus.  The project was commissioned in early 2019 and has been in continuous operation except for a few months break in the second half of 2019.  The general operational pattern has been the charging the system overnight at around 20kW and the discharging it at 100kW maximum inverter power during evening peak hours.  Performance results will be reported and include power and current sharing between the strings, the overall efficiency, and the general behaviour of the two batteries.  The second part of the presentation concerns modelling of the dual battery system with the aim of gaining a better understanding of DC linked hybrid battery behaviour.  Two designs of GS–Yuasa lead–acid batteries (LEV50 and SWL3300) have been tested at the University of Southampton to gather data for modelling purposes.  Pulse discharge and constant-current charge/discharge, at different C rates, were performed.  The resulting equivalent circuit models were used in Matlab/Simulink simulation studies of different lead–acid and Li-ion hybrid battery systems with varying numbers of cells and strings.  This approach was adopted to provide further insights into the behaviour of a given battery and thereby aid the optimisation of its configuration for given applications.

Presenters

Mr Peter Stevenson Senior Technical Co-ordinator, GS Yuasa Battery Europe Ltd, United Kingdom

Peter Stevenson holds a MA degree in Natural Sciences from the University of Cambridge.  He joined Ever Ready Advanced Projects Group in 1979 to develop primary lithium cells and photo-electrochemical devices.  Peter moved to Yuasa Battery UK Ltd in 1985 to manage the development of valve regulated lead–acid products and processes for the European market.  Since 2014, he has focused introducing of GS-Yuasa Li-ion industrial batteries into Europe.