Not surprisingly, speakers during last Friday’s Advanced Powertrain session at the Center for Automotive Research’s Management Briefing Seminars in Traverse City were optimistic about the potential for lithium-ion batteries. But they agreed that further investment is needed to improve engineering, manufacturing and design aspects, according to AutoTech Daily.
Denise Gray, director of General Motors Corp.’s hybrid energy storage systems operations, pointed out the variety of lithium battery chemistries and the need to suit a particular chemistry to a specific use. She also notes the continuing necessity to lower battery weight while maintaining a 10-year, 150,000-mile life cycle.
Gray says GM hasn’t encountered any crippling design or supplier-related issues in the development of the upcoming Volt electric vehicle. She attributes the program’s success to date in part to data collected during GM’s short-lived EV-1 program. Among the hurdles she says still need to be addressed are improving thermal management and increasing the number of suppliers developing high voltage controls.
Lithium-ion battery supplier A123System’s president David Vieau spoke about the potential of “smart” battery cell chemistries that could reduce the system cooling required and lower or eliminate the need for electronic cell balancing. Such designs also could mitigate overcharging and excessive discharging. He doesn’t expect the ramp-up of hybrid and electric vehicles to have much impact on material prices because most of the chemistries being developed rely on common, recyclable materials.
Vieau and others addressed the potential for grid balancing. They note that a lithium-ion battery could have a useful life of up to 30 years and thus could provide electricity back to the grid well after the original vehicle itself is retired. He envisions recharging times eventually falling to five minutes and prices dropping to 40 to 60 cents per watt-hour in the near term and to as low as 25-30 cents in the future.
Justin Ward, advanced powertrain manager for Toyota Motor Co.’s North American Engineering & Manufacturing unit, said Toyota is developing next-generation batteries such as metal-air, solid and nano-particulate systems in addition to lithium-ion technology. In newer generation hybrids, Toyota also is using its experience in DC/DC converters and high-speed motors to improve efficiencies.
Ward says plug-in hybrids and all-electric vehicles need to be further examined in relation to the electric grid. Although recharging at night evens out usage patterns, Ward notes that off-hour operation of the grid typically runs on coal vs. natural gas or fuel oil during peak times. Likewise, CAR Chairman David Cole says a clearer differentiation between “old” and “new” carbon is needed when evaluating “green” technologies and enacting legislation.
Panelists also said control systems will be needed to prevent the grid from drawing down too much power on hot days.
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