Grid Energy Storage Performance Improvement Using Controlled Overcharge

Electric Applications Incorporated (EAI) has reported the effect of combining a novel means of minimizing overcharge with a high-level partial state-of-charge (PSoC) operation.  Commercially available pure-lead AGM 12V-monoblocs were operated in the laboratory under ambient temperature conditions, using a condensed time profile, and simulating BESS operation in applications such as load-levelling or peak-shaving.  The overcharge delivered to the monoblocs was reduced to an extremely low level so that the batteries were effectively operating under PSoC conditions with a high, top SoC level.  Using this methodology, the normal equalization process associated with PSoC duty was no longer required, the lifetime energy throughput of the monobloc was improved and the charging times were significantly reduced.  EAI conducting work funded by the Consortium for Battery Innovation (CBI) is investigating the application of this minimum-overcharge/high level PSoC methodology (controlled overcharge protocol) to lead–acid technologies other that pure-lead AGM (such as gel and thick plate, non-carbon enhanced AGM products) with similar life-extending benefits.  EAI is also investigating if this controlled overcharge protocol can be effectively applied to the multiple parallel strings of numerous series-connected cells that are required to provide the capacity of a typical BESS.  This presentation summarizes work to date in this CBI research program, including test methodology, current test results and serial/parallel string limitations.


Mr Tyler Gray Director, Projects Management, Electric Applications Incorporated, United States

Tyler Gray is an electrical engineer and has over ten years of experience in evaluation and testing of electric vehicles and battery systems. In his role as Director, Projects Management at EAI Tyler develops certification plans and test protocols to qualify battery systems to industry standard safety requirements and life safety code requirements.