Li-ion research paves way for longer lasting EV batteries

German scientists claim to have produced lithium-ion batteries with a much longer working life than those currently on the market. The team at the Ulm-based Zentrum für Sonnenenergie- und WasserstoffForschung (Centre for Solar Energy and Hydrogen Research) Baden-Württemberg report developing a battery that retains than 85 per cent of its initial capacity after 10,000 full cycles while possessing qualities comparable to batteries produced by leading Asian manufacturers, including power density.

“After 10,000 complete charging and discharging cycles with a complete charge and discharge cycle per hour (2 C), our lithium batteries still have more than 85 per cent of the initial capacity,” reports Dr. Margret  Wohlfahrt-Mehrens, head of the Ulm facility’s Accumulator Material Research Department. “That also provides excellent prospects for a long calendar life.” Long service life is an essential requirement from automotive OEM customers. Batteries with the lithium-ion technology must be capable of functioning reliably within a car for at least ten years without the battery capacity dropping to less than 80 per cent of the rated value.

The active materials used in the batteries were sourced from German companies and ZSW designed the cells, developed the manufacturing process and then produced a small sample series of type 18650 batteries. The cells have a power density – or available power to weight – of 1,100 watts per kilogramme. For an electric vehicle, this figure represents short charging times and good acceleration. The ZSW-developed technology creates a foundation for manufacturing larger pouch cells and prismatic cells. 

A total of 10,000 complete charging and discharging cycles is the equivalent of charging a battery daily for more than a quarter of a century.