These days, you don't need to be an engineer to know what a lithium-ion battery is. Half the country now knows that lithium-ion chemistries played a role in fires aboard Boeing's 787 Dreamliner. The term has been used in newspapers, on television news programs, and on tens of thousands of websites around the world.
So it's probably inevitable that much of the public is now making the connection between Boeing's fires and electric vehicles. And news organizations are helping make that connection.
A recent NBC News story asked whether Boeing's woes would "short-circuit" electric cars. Numerous other news sites have tracked the stock market effects of the debacle on electric vehicle manufacturers. And a Chicago Tribune story about imported products even used a graphic depicting burning bread in a toaster with Boeing's name on it. A caption under the photo asked, "...what might be expected of lithium-cobalt oxide batteries?"
Boeing's batteries overheated and burned (left) onboard a 787 (right), but that shouldn't be an indictment of lithium-ion chemistries.
(Source: NTSB, left; Boeing, right)
If all of that is beginning to sound like an indictment of lithium-ion batteries, then that's a shame.
Yes, it's true that today's electric cars and plug-in hybrids use lithium-ion batteries. And it's true that lithium-ion is more prone to overheating than, say, lead-acid or nickel-metal hydride chemistries. But the term that too often gets left out of these discussions is "engineering." This is what engineers do. It's what they're good at. They take energy sources and make them do work. And if they do their jobs right, then they do it safely.
"No matter how you slice it, a lithium-ion battery, or any high-performance battery, is a package of energy," Elton Cairns, professor of chemical and biomolecular engineering at the University of California-Berkeley, and a designer of fuel cells for NASA's Gemini flights, told Design News. "If they had put a similarly-sized vessel of gasoline in place of that Boeing battery, it would have been an even bigger fire hazard."
To be sure, the lithium cobalt oxide chemistry used by Boeing is even more energetic than other lithium chemistries. But that's not really the issue. The issue is that engineers are supposed to determine the energy level, and then build in mechanisms to make the situation safe for users.
That's why engineers at General Motors put 144 plates filled with liquid coolant between the lithium-ion cells on the Chevy Volt. It's why Toyota uses 42 sensors to monitor temperatures of the Prius PHV's lithium-ion batteries, as well as three fans to cool the cells. It's also why engineers use special electrical connectors to prevent against shorts inside and outside their batteries. And why they employ battery management ICs to monitor performance. It's all part of the process of learning to manage the energy.
The point is, lithium-ion is energetic, but with proper engineering, not dangerous. Over many decades, engineers have learned how to safely operate internal combustion engines with gasoline, stoves with natural gas, and jets with jet fuel. Yet, we don't fret about the gasoline, jet fuel, or natural gas. Why? Because we expect engineers to manage the risks. And engineers will do the same with lithium-ion batteries, assuming our risk-averse society doesn't block the way.
"As long as you have a battery that contains a lot of energy, you'll never have 100 percent protection against some kind of failure," Cairns told us. "It's all a matter of proper design and acceptance of a certain amount of risk."