General Motors has awarded two separate contracts for advanced development of lithium-ion batteries and packs for the electric drive E-Flex System used in the Chevrolet Volt.
One contract will go to lithium-ion battery supplier Compact Power, Inc. (CPI), based in Troy, Mich. CPI is a subsidiary of Korean battery manufacturer LG Chem. A second contract has been awarded to Frankfurt, Germany-based Continental Automotive Systems, a division of Continental A.G., a tier one automotive supplier that will develop lithium-ion battery packs using cells from A123Systems.
GM Chairman and CEO Rick Wagoner made the announcement at the annual shareholder meeting today in Detroit. GM says that it continues to assess other solutions to quickly bring lithium-ion batteries to production.
GM selected the two companies out of the 13 technical proposals it considered to provide advanced lithium batteries for both range-extender electric and fuel cell variants of the E-Flex architecture.
The signing of these battery development contracts is an important next step on the path to bring the Volt closer to reality. Given the huge potential that the Volt and its E-Flex system offers to lower oil consumption, lower oil imports, and reduce carbon emissions, this is a top priority program for GM.—Rick Wagoner, GM Chairman and CEO
The E-Flex System was first shown as the plug-in battery electric propulsion system for the Chevrolet Volt concept vehicle at the North American International Auto Show in January. (Earlier post.) A plug-in fuel cell variant of the E-Flex system was shown at the Shanghai Auto Show in April. (Earlier post.) The “E” stands for electric drive; the “Flex” represents the architecture’s adaptability to be configured in several vehicle packages operating on various sources of electricity.
GM said that the suppliers chosen demonstrated solutions that best met the specific energy, power, mass and durability requirements for the battery in the E-Flex range-extender variant. The battery for the fuel-cell variant requires half the energy and power, but must be integrated and connected to the vehicle in a similar way.
This technology is developing rapidly. These contracts are an opportunity to deeply understand the differing battery technologies before making a production decision.—Denise Gray, GM Director of Hybrid Energy Storage Devices
A123Systems recently introduced its new 32-series family of automotive-class, large-format Li-ion cells. The 32-series lineup initially consist of two cells with doped nanophosphate electrode designs, based on the same iron phosphate (LiFePO4) chemistry as the mass-produced M1 cell: the 32113 M1 Ultra for hybrid electric vehicles (HEV) and the 32157 M1 HD for plug-in hybrid electric vehicles (PHEV). (Earlier post.)
A123Systems designed the 32157 PHEV cells to deliver the lowest cost per watt hour ($/Wh). The 32157 offers a volumetric density of 260 Wh/L, can deliver very high power at a lower state of charge with a 10+ year projected service life, and has a projected cycle life of more than 7,000 cycles at 100% DOD, according to the company.
CPI makes large-format cells using a proprietary lithium manganese spinel (LiMn2O4) cathode with additives to improve calendar life under high temperature conditions.
CPI’s 12-month program with GM involves the development of battery cells and battery packs. LG Chem, CPI’s parent company, will develop and supply the cells, while CPI will focus on pack development and assembly including mechanical integration, thermal and electronic management and vehicle interface.
The CPI program will have three phases:
Battery cell/module development and testing;
Battery pack development and testing; and
In-car integration and testing.
In work with the Department of Energy’s FreedomCAR initiative last year, CPI delivered a cell design that exceeded the FreedomCAR goal of 300,000 cycles. The company also has developed a patent-pending abuse tolerant separator (a membrane between the electrodes) that will further improve the performance of this cell design.
Recent test data shows that the company’s latest chemistry can achieve more than 15 years of calendar life in an automotive environment.