Tesla Motors' hybrid battery pack system for extended range

This patent application became news in mid-September 2013. It is a hybrid battery pack, meaning that it uses two kinds of battery cells. One set of cells would be lithium-ion, while the other set would be some form of metal-air battery cell. The metal-air cells have much higher energy density, but cannot sustain higher energy rates necessary for driving a car. The lithium-ion cells would be used to directly power the drive train, while the metal-air cells would be used to keep the lithium-ion cells charged up.

A block diagram of the system, along with a schematic of the energy flows through the system.

The idea is to have a "controller" managing energy flows between the two battery packs and the drive train.

View the patent application at uspto.gov or Google docs viewer or Google patent search or http://pdfaiw.uspto.gov/11/2013/15/018/1.pdf or view it using Google Docs