A new procedure allows quick assessment of the suitability of used electric car batteries for reuse in stationary energy storage systems. The automotive lithium-ion battery grading process was successfully transferred to a A battery pack being tested in the lab. Source: University of Warwickpilot second-life facility, where a target of 1 MWh of second-life energy storage was achieved.

The Warwick Manufacturing Group at Warwick University, U.K., collaborated with Nissan, Element Energy and Ametek to develop the time-saving classification methodology, based on the evaluation of 50 used Nissan Leaf batteries. Entire battery packs and modules can be graded in three minutes instead of three hours, and the sorting approach distinguishes between used batteries suitable for second-life use or material recycling.

Module testing equipment based on electrochemical impedance spectroscopy and algorithms determine battery state of health as a measure of the unit’s ability to store and deliver electrical energy, compared to a new battery. The graded second-life battery packs can provide reliable, convenient energy storage options for diverse applications.

Ametek plans to commercialize the grading system and algorithms in the near term.