For instance, these new vehicles emit far fewer greenhouse gases--none in the case of electric cars--and their fuel costs are significantly lower.

Some issues carry over from internal-combustion-engine vehicles, however, including the risk of overheating. But rather than worry about the radiator, people behind the wheel of electric and hybrid automobiles must focus on lithium-ion batteries.

To address this issue, Dana Holding Corp., Maumee, Ohio, developed a Long heat exchanger specifically geared toward electric and hybrid vehicles.

"The battery people need both heating at the lower temperature, much like an internal-combustion engine, and they also need cooling during the charging and discharging part of the cycle," says Ted Zielinski, technical director at Dana Thermal Products Group. "Their heat-exchange needs are different from an internal-combustion engine, but they still need heat exchange, depending on the part of the cycle."

This technology is the first of its kind, and it debuted on the 2010 all-electric Roadster Sport from Tesla Motors, San Carlos, Calif.

According to an article in The (Toledo) Blade, "Dana's unique heat-exchange technology cools the Roadster's battery by transferring heat generated within the battery to the vehicle's control system. Excessive heat kills batteries, cutting short their capacity to recharge and the number of times they can be juiced back up, engineers say. By keeping the batteries cool--and warm when it's cold outside--engineers can extend battery life and make it easier to transfer energy from where it is stored to where it's needed."

History lesson
Zielinski says work on the heat exchanger began about six years ago and that evolving technological and environmental needs played a role in the device.

"It's an offshoot of other heat exchanger work we did in the past," he says. "We developed technologies as the refrigerants that the automotive people were using were changing. There was a change back in the 1990s from ozone-depleting R12 refrigerant to what we're using now: R134A. There are some other new refrigerants being proposed, such as R1234 and some other ones that are based on propane or CO2. Looking into what they would need, we developed this particular heat exchanger."

Additionally, Tesla is just one company that has benefited from Dana's commitment to the hybrid and electric segment, according to Zielinski. The company also worked on the cooling system for a hybrid pickup truck by General Motors, Detroit.

Material matters
The engineers at Dana used high-strength aluminum alloys, as well as an aluminum brazing process, to develop the heat exchanger.

"Aluminum is the material we work with the most right now," says Zielinski. "Starting in the early 1990s, we went to aluminum. It has good heat-exchange properties for heat transfer."

He also says the metal's light weight and corrosion resistance offer advantages, especially in regard to automotive applications, and that aluminum has some value proposition compared with other metals.

"Depending on the market, it's lower cost than, say, stainless steel or brass, which was typically used for heat exchangers in the past," says Zielinski. MM