The 2010 Toyota Prius hybrid has officially been revealed at the 2009 Detroit Auto Show. Click here for all the details and images.

Despite being at the forefront of hybrid technology, even Toyota is having trouble bringing next-generation models to market using lithium-ion battery technology. It was expected the new drivetrain would be released towards the end of next year, but the latest reports out of Japan place them firmly in 2009.

Current Toyota hybrids use nickel-metal hydride batteries, but it was hoped that moving to lithium-ion would increase the capacity and decrease weight as well as cost. The company developing the new battery tech, Matsushita Industrial, has said that the development has been delayed due to safety concerns about how the batteries would react in case of an accident or fire, reports Reuters.

Toyota has been coy about the release date, but they must surely be feeling the heat as the rest of the world’s top carmakers gear up their own plans for hybrid production.