Long Life, High-Performance Battery for Start-Stop Applications

For use in congested traffic, start-stop vehicle technology (micro-hybrid) offers the promise of significant increases in fuel economy and reduction of pollutant emissions, without large increase in the vehicle sales price. A key enabling component of the start-stop system is the battery. Present start-stop systems employ lead acid batteries because of their low initial cost and excellent low-temperature performance, but these batteries suffer from life limitations especially when subjected to repeated deep cycling and high charge rates. Consequently, alternate battery systems with improved life characteristics are the key to enabling widespread adoption of start-stop vehicles. Li-ion technology is the leading candidate to replace lead-acid batteries in start-stop systems and several battery companies have announced Li-ion batteries for start- stop applications. However, most Li-ion battery systems offered today suffer from one or more disadvantages such as poor low-temperature performance, poor high-rate charge acceptance, or high cost relative to lead acid batteries. This is at least in part because the materials in these batteries are not optimized for the specific requirements of start-stop applications. CAMX Power is developing Li-ion technology for start-stop applications that overcomes the limitations of the current Li-ion systems by tailoring its proprietary CAM-7 cathode material for use opposite lithium titanate anode (LTO) anode in pouch cells that provide excellent cold-cranking capability, elevated- temperature stability, cycle life and safety for 12V start-stop batteries. CAMX Power has already shown that CAM-7 cathode/LTO anode pouch cell technology provides excellent -30 °C cold cranking capability and elevated-temperature stability (without pouch cell gassing/swelling). In the proposed program, we will optimize the CAM-7 material for the start-stop battery application, and will develop a scheduled maintenance procedure for CAM-7/LTO start-stop vehicle batteries that further extends their performance and life. The CAMX POWER start-stop battery technology will facilitate widespread commercialization of start- stop micro-HEVs by enhancing the available energy, dynamic charge acceptance, and life of Li-ion batteries used in micro-HEVs. Rapid, widespread adoption of affordable micro-HEVs in traffic- congested areas of the country can yield benefits including reduced adverse health impacts from pollution in urban and other high traffic areas, reduced adverse environmental and economic impacts of global warming, and reduced economic impacts of fluctuations in global petroleum supply and price.