Real world battery diagnostics model based and Prius case study

A new method of diagnosing failure within large series connected battery packs is presented taking the Toyota Prius as a specific case study. The new method involves plotting battery minimum and maximum block number against battery current in a histogram type plot. Failures such as corroded sensing wires, “bathtub” type capacity fading throughout the battery pack and individual module of block failures can be easily identified using this method. A relationship between C_bulk of the two capacitor model and the capacity of the battery module is also briefly presented and confirmed using a measurement of the slope of the discharge curves. The two capacitor model is then built to confirm the new method with good results.