And those cost cuts have done little more than offset skyrocketing prices for nickel based hybrid batteries. The most likely candidate to replace nickel is lithium.
Hermance thinks it will take about three years to make them viable for hybrid vehicles.
Lithium-based batteries cost a little bit more than nickel-based ones now, but higher production volumes should drive prices down, he said. An added benefit is that lithium can store more electricity with less battery than nickel. That could mean cutting vehicle weight, further improving trunk space and fuel economy, or having higher-capacity batteries.
Higher-capacity batteries could lead to plug-in hybrids. Prototype plug-in hybrids can run longer without using gasoline. That could allow some commutes to be done without using gasoline at all.
Hermance said the first lithium-battery-powered hybrid should be on the road within three years. He expects all hybrids to be lithium-based within 10 years.
"Plug-ins will fall somewhere between there," Hermance said, adding that he expects those vehicles to be marketable within five years.