The hybrid battery test lab at the GM Technical Center
Earlier this week Long Beach was host to the Advanced Automotive Battery and Ultracapacitor Conference (AABC) which featured a panel discussion on what it will take to bring lithium ion battery technology to the mass market. Included on the panel were GM's Joe LoGrasso and Mark Verbrugge and Ford's Ted Miller. All acknowledged that lithium batteries are inevitable, and that it's just a matter of ironing out the details over the next couple of years. Of course many of those details aren't exactly trivial, but they can be overcome.
Nickel metal hydride batteries are known quantity and thermal and charging management are fairly straightforward. The biggest problem is limited energy/power density when compared to lithium batteries. There is also a decent amount production capacity for large scale NiMH batteries although nickel prices have been on the rise of late. To date no one has produced large quantities of automotive-sized lithium cells. Tesla is building their battery packs up from 6,800+ laptop cells which means each pack will have almost 14,000 interconnects any of which could be defective or fail. The big manufacturers want to use larger cells to cut the number of interconnects and reduce the number of potential failure points.
Anther area that battery manufacturers and car companies are addressing is standardizing interfaces between the vehicles and battery controls as well as the way battery life and charge history is calculated for warranty coverage. Improved models of the battery behavior are important to ensuring that the management software extracts the maximum output and life out of the battery. There's more at GreenCarCongress.