Mercedes-Benz High-Performance Engines (HPE) designs and manufactures engines and hybrid power systems for Formula One racing. When Formula One's governing body elected to allow teams to integrate Kinetic Energy Recovery Systems (KERS) into their vehicles starting in the 2009 racing season, Mercedes-Benz HPE when looking for the best technology to build its KERS system. This case study describes why Mercedes-Benz HPE selected A123's Nanophosphate lithium ion battery technology for its KERS, the design challenges the companies faced and the impressive results on the track. .