None of this would be an issue, of course, if EV battery packs weren't so big in the first place. The packs, often weighing more than 400 pounds, can have trouble releasing their heat, because they're so much bigger than laptop or cellphone batteries. That's why most electric car makers are employing complex active cooling systems that cellphones don't need.
"Can you put cooling channels" in an EV battery pack, Sadoway asked. "Sure. But they may not hit the price point you want."
Researchers are working on new chemistries that could supplant the lithium-ion formula, but such batteries are still a long way from production. Lithium-sulfur, which is said to have higher energy and better heat characteristics, could reach production for small products, such as laptops, in the next 10 years. Lithium-air, long talked about as a high-energy replacement for lithium-ion, might be two or three decades from widespread use, Cairns said. Batteries based on other metals, such as magnesium, are also under consideration.
The bottom line is that today's technology of choice may be facing challenges ahead. Automakers are relying on a steep drop in battery cost to help electric car sales take off. And additional safety constraints aren't going to help them reach their cost targets, especially since cost was already an issue before the Volt fires.
"My position is that we must get beyond lithium-ion for vehicles," Cairns said. "The lithium-ion systems of today are inherently too expensive and too low in energy for electric vehicles. If we use lithium-ion as we now know it, the EV will always be a specialty vehicle."