May 7, 2020: Research by Arizona-based Electric Applications into optimizing lead acid batteries for energy storage systems with the use of an intelligent BMS has won backing from the Consortium of Battery Innovation, CBI said on May 4.
The 18-month study will look at optimizing performance so that lead batteries can meet the life cycle and total cost of ownership requirements of the emerging BESS market, said CBI managing director Alistair Davidson.
“The project includes life cycle testing of two different battery constructions using a high SoC cycle simulating a grid energy storage profile combined with controlled overcharge techniques,” he said.
“The batteries will be cycled under laboratory conditions simulating a typical BESS field environment. The controlled overcharge algorithm will be customized to each battery early in testing, to optimize the performance of each battery construction.”
During the study, an electrical current will be sent across large strings of batteries which will be monitored and controlled using the BMS, which will look at each string discharge and integrate it with the capacity discharged.
“This capacity will then be used to determine the charge return required to achieve the desired overcharge (105%-110%),” said Davidson. “Capacity returned during charge will be precisely controlled for each string.”
He said previous experiments had indicated that the best capacity for optimizing performance in ESSs was with batteries overcharged at between 105%-110%.
Two types of battery will be tested during the study — a traction thick plate gel type, and a standard AGM construction — in simulated BES systems of 1MWh-2.5MWh.
“This capacity represents a typical near-the-meter BESS application, consistent with applications such as peak shaving or renewable shifting,” said Davidson.
“Batteries of these two types will be assembled into two separate battery packs of approximately 50kWh. Each battery pack will consist of four parallel strings of 36-40 series connected cells, simulating a portion of the typical series/parallel configuration of a BESS.”
Several of CBI’s projects have had to be delayed because of the pandemic, but some, including this one, are back up and running, with others due to re-start this year.