New Coulometry Technique for Li-ion Battery Durability Analysis

Large Li-ion factories are being built around the world in an attempt to dramatically lower cost through economies of scale.At the same time, new market opportunities are becoming accessible to Li-ion as the technology improves.For many of these technologies, the levelized cost of energy storage is the primary metric, not $/kWh.Cycle life varies tremendously depending on cycling conditions, chemistry, cell design, and manufacturing quality.Cell manufacturers and storage integrators are very interested in new technologies that can improve the abuse tolerance of Li-ion batteries resulting in improved cycle life.But proving new technologies or even iterating on existing formulations is challenging given that under some load profiles Li-ion chemistries can cycle for many years.Such long evaluation timeframes are not conducive to technical advancement.New characterization techniques are required that provide rapid insight on capacity loss and degradation mechanisms with sufficient clarity to make informed design decisions.This project will develop a new battery characterization tool that allows the measuring of capacity loss rates of Li-ion batteries under a variety of specific use scenarios.Xilectric’s proposed characterization technique provides insights not available from existing techniques providing a more complete picture of the capabilities of the variant of Li-ion chemistry under test.In particular, our technique is able to provide several measures of fidelity under realistic cycling conditions while avoiding artificial accelerated aging conditions such as extreme temperatures and potentials as well as full depth of discharge cycling.The information provided by the new test can be used to develop better battery management algorithms, to improve on cell design, and to select Li-ion formulations best suited to the end-user application.In Phase I, the basic performance requirements of the new coulometer system were established.Several batteries were characterized with the new technique.In phase II, the full system will be prototyped.Once validated, Xilectric would expect strong commercial interest in the new device from various Li-ion cell manufacturers, end-users, researchers, and academic institutions.