Long in Development, Fuel-Efficient Ultracapacitors May Shine -- or Flop -- Later This Year

Last Updated Apr 13, 2010 9:00 AM EDT

Ultracapacitors -- battery-like devices that charge and discharge extremely quickly -- have long been technology-in-waiting for high-tech cars. But they're due to have their day in the sun later this year. According to Maxwell Technologies' CEO, a major European automaker expects to release a hybrid vehicle this year that couples advanced batteries with the company's ultracaps.

The new hybrid -- and others like it -- are motivated by legislation that requires them to built very clean cars at an affordable price. Beginning with the 2012 model year, automakers selling cars and trucks in Europe will have to meet a stringent tailpipe greenhouse emissions standard of 130 grams per kilometer. It's caused them to start thinking differently and to call on new technologies. The penalties for carmakers failing to comply with the Euro standards (which are targeting 95 grams per kilometer by 2020) is no slap on the wrist. In the first year, only 65 percent of the fleet has to be in compliance, but it ratchets up to 100 percent by 2015. The fine is five euros ($6.80) per vehicle for the first gram over the target, 15 euros ($20.46) for the second gram, 25 euros ($34.10) for the third and a whopping 95 ($129.60) for every other gram.

There's no relief for carmakers in the U.S., either. By 2016, the standard is 250 grams per mile, and the penalty is $5 for every gram over the target.

San Diego-based Maxwell thinks it has a cost-effective solution for carmakers. The company makes the K2 2000 ultracapacitor (about the size of a soda can), which could be of excellent strategic use with cars -- known as "mild hybrids" -- that use electric motors for extra power (and not for actually driving the car). According to CEO Dave Schramm in an interview with BNET Autos, ultracapacitors have advantages over the batteries they superficially resemble because they work well in a broad temperature range, run through millions of charge and discharge cycles, and both accept and release their electric charges quickly.

"Ultracapacitors aren't of much use just by themselves," said Ted Bohn, an automotive engineer at the Department of Energy's Argonne National Laboratories. "But when you couple them with lithium batteries, they dramatically boost the performance of the entire vehicle. Ultracapacitors give an electric vehicle the initial boost it needs to get going."

Similarly, Energy Secretary Steven Chu said at the Washington Auto Show in January that ultracaps have a role to play in concert with batteries. "We believe this can improve the gas mileage of all vehicles,: he said. "It's technology that just needs to be hybridized with the batteries we have today."

Ultracaps are ideally suited for use with a mild-hybrid drivetrain that shuts down at stoplights. Ultracaps, instead of a large battery pack, restart the engine, and are also on hand to provide power for acceleration. They can be quickly recharged with the power grabbed through regenerative braking. A secretive company called EEStor has gotten much of the publicity for ultracapacitor technology, but so far has failed to deliver on its sensational promises.

This is exactly the approach the major European carmaker is taking with the new vehicle, which will appear later this year. Maxwell's partner in this unnamed hybrid car is the $30 billion Continental AG parts supplier, a competitor to Bosch in Europe. Continental expanded with acquisition of another high-profile European auto supplier, Siemens VDO, in 2007.

"They're ramping up the car now," said Schramm, who added that he expects the model's volume to double by 2012. "We're already shipping product." Schramm said that starting the car, especially in cold weather, is the largest load batteries go through. Ultracaps allow a much smaller pack. "We're definitely taking cost out of the system," Schramm said. "Batteries don't like the kind of power spikes you get with the start-stop cycle, but that's the way ultracaps work best."

According to Schramm, a 25-year General Motors veteran, "Lead-acid batteries can't absorb enough energy in the few seconds that regenerative braking is active. You need either a more advanced battery chemistry or an ultracap that can recharge quickly."

Schramm thinks the majority of cars coming out of Europe by 2014 or 2015 will have start-stop technology, and indeed the so-called "micro-hybrids" are already becoming common there. In the U.S., automakers have had trouble getting EPA mileage credit for adding the relatively expensive ($400 to $600) feature, so it hasn't yet been added to any conventional cars here.

Maxwell ultracaps are aiding regenerative braking systems on 850 hybrid buses in China, and 2,000 around the world. The company is working with Azure Dynamics, Ford's partner in the new Ford Transit Connect electric van, on that project. The hybrid bus business has helped the company grow, from a $57 million company in 2007 to $82 million in 2008 and $100 million last year.