Chevrolet Volt; photo by Jil McIntosh. Click image to enlarge
By Jim Kerr
As Chevrolet’s Volt electric car nears production, GM continues to work on the battery technologies that will enable these electric vehicles to operate in an economical and efficient manner. While past hybrid vehicles have traditionally used Nickel Metal Hydride batteries, GM has announced the Volt will use Lithium Ion battery technology and that the Volt’s advanced propulsion system will be adapted to other bodies and platforms in the future. Appropriately so, GM has named this propulsion system “Voltec.”
So why Lithium Ion batteries? According to Bob Kruse, GM’s Executive Director of Global Vehicle Engineering, Lithium Ion hits the “sweet spot.” When you look at the cost of production versus the payback in power and durability, Lithium Ion technology has an advantage. Laptop computers, cell phones and PDA’s are powered by Lithium Ion batteries because of the power they can provide in a small package, and that advantage works for automobiles too.
All Lithium Ion batteries are not equal, however. There are many different chemistries and GM evaluated over 100 different types of cells before choosing what they see as the most effective chemistry. Announced at the Detroit auto show, GM is partnering with LG Chem to produce the Voltec battery and it will have a manganese-based chemistry. LG Chem was chosen not only for the battery chemistry but also for the battery safety systems that are incorporated into the cells; gas tanks on conventional vehicles have many safety features built into them and likewise, so must the battery cells. Part of this is a reinforced cell separator. GM is keeping many details of the Voltec battery system hush-hush for now but you can expect to hear much more once the vehicles are in production. With production of the batteries in Michigan and the largest battery test lab in the U.S. scheduled to open later this year, GM feels confident in moving the Voltec solution forward.