Today at the North American International Automotive Show, in Detroit, Toyota announced that later this year, it will release a version of the Prius hybrid car whose battery can be recharged from an ordinary power outlet. By moving up the delivery data of the plug-in vehicle–originally scheduled for 2010–Toyota has slipped ahead of GM, whose Chevy Volt plug-in is promised for late 2010.
Toyota’s fidelity to hybrid technology marks a sharp contrast with rivals such as Renault and Mitsubishi, which are planning to leapfrog the hybrid in favor of fully battery-powered electric vehicles (EVs). At the auto show, several U.S. automakers appear to be leaning in the same direction, with Ford Motor, in particular, vowing to release an EV commercial van next year and an EV commuter car in 2011.
Even Toyota is hedging its bets, presenting a battery-powered EV based on its four-seat iQ and promising to begin selling a similar EV commuter car in the United States by 2012. But Toyota explicitly ruled out abandoning hybrid technology anytime soon, issuing a definitive statement on the eve of the Detroit show calling hybrids its “long-term core powertrain technology.”
The 2010 Prius available to consumers will still come equipped with a nickel-metal-hydride (NiMH) battery pack and no plug, but Toyota says that it is “plug-in ready”–designed and engineered to accept a lighter and more energy-dense lithium-ion battery pack that can be charged from the grid. Toyota will also produce 500 lithium-powered plug-in Priuses for its commercial and government leasing customers starting later this year. Toyota-Panasonic joint venture Panasonic EV Energy will supply the lithium batteries.
The fact that the plug-in battery pack can be swapped in for an ordinary hybrid battery suggests that it will be relatively small, and that the plug-in Priuses will have a smaller electric-only range than the Volt and the Chinese-built BYD F3DM. The plug-in vehicles that Toyota has been testing in Japan, France, California, and the United Kingdom are Priuses equipped with a second NiMH battery pack that gives them less than 10 miles of electric-only range.
Limiting the battery size is a conscious decision. Recent studies suggest that a limited amount of electric-only range may be optimal for plug-ins, especially in the United States, where half of electricity generation is coal fired. A working paper by Duke University researchers, released in November, predicts that plug-in hybrids storing enough electricity to travel 40 miles on a charge–like the Chevy Volt–will offer few if any greenhouse-gas reductions relative to conventional hybrids. Such long-range plug-ins will likely also cost more per mile, thanks to the high price of the lithium-ion batteries required to store the electricity.
In contrast, research to be delivered today by Carnegie Mellon University mechanical engineer and design expert Jeremy Michalek at the National Academy of Sciences’ Transportation Research Board meeting finds that plug-ins with just 20 miles of electric range are likely to best conventional hybrids in both cost and carbon footprint–assuming they are charged frequently.
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