Sen. Joe Biden, D-Del., introduced legislation Thursday that would boost federal investment in the development of lithium ion batteries that he says is critical for producing the next generation of hybrid vehicles.

Biden's bill, called "The American Automobile Industry Promotion Act of 2007," would provide $100 million a year for five years toward research and development of battery technology. The funds would go toward battery research at national laboratories, small businesses and educational institutions.

Supporters say lithium ion battery research is a key to the development of advanced hybrid technology such as plug-in hybrid cars. Unlike gas-electric hybrids like the Toyota Prius, plug-in hybrids use electric power and travel extended ranges without using gasoline. But the development of plug-in cars is stunted because more research is needed in lithium ion batteries, Biden said. Such batteries are expensive and there are very few manufacturers in the United States.

"Right now, the Japanese dominate the market for lithium ion batteries because they invested hundreds of millions of dollars in developing this technology and in supporting their domestic industry. ... American auto manufacturers are playing catch-up and we need to move quickly," Biden said.

Automakers in Delaware, including DaimlerChrysler AG and General Motors Corp., which are jointly working on hybrid technology, are expected to benefit from the bill.

"Battery technology is definitely the most significant challenge to not only hybrids, but also fuel cell vehicles," said Nick Cappa, Chrysler's Advanced Technology spokesman.