Let's see? Boostcap, Boostcap, Boostcap. Where have we heard this before? Ah, yes. Back in November 2006 we first heard about Maxwell Technologies' 125 volt ultracapacitor and we later learned about the heavy duty version (390 volts) for hybrid buses and how the ultracaps might go into Chinese vehicles and be used in Milan. But, if you haven't been following this news, you can get your fill of BOOSTCAP ultracap news at the American Public Transportation Association EXPO (AKA "public transportation's premier showcase") in San Diego next week. Maxwell will be showing all of its heavy duty BOOSTCAP ultracapacitors - everything from 16 to 1,500 volts. If that's not enough power for you, then please tell us what vehicle you're running.

[Source: Maxwell Technologies, Inc.]

About a year ago, Maxwell Technologies told the world about the Chinese government using its ultracapacitors in various official vehicles. Another July brings another announcement, and so we learn that the city of Milan, Italy will soon be using Maxwell's ultracap modules in its hybrid and electric buses. The 125-volt BOOSTCAP ultracapacitor modules will store energy from the bus' brakes and then spit it back out for torque assist when the driver steps on the accelerator. Overhead electric lines or a diesel generator will supply the rest of the energy needed to move the public transit vehicles. Milan has ordered 70 buses from Vossloh Kiepe and Van Hool and will soon take deliver of the first 15. More details after the break.

[Source: Maxwell Technologies Inc.]

When we're talking about the word "hybrid" in automotive circles, it doesn't always mean a gasoline engine with a powerful battery pack tied on. For Maxwell Technologies and Tianjin Lishen Battery, hybrid describes a new sort of energy storage product that combines ultracapacitors with lithium-ion batteries. The two companies recently announced they would partner up to produce this hybrid power source, and samples should be available early next year, possibly in EVs. The Maxwell press release doesn't give any details and simply says, that "The companies have identified a number of initial target applications for the new products, ranging from quick-charge cordless tools to electric vehicles."

David Schramm, Maxwell's president and chief executive officer, said this hybrid tech "will give end-users the best of both worlds in terms of the long cycle life, rapid charge/discharge characteristics and low temperature performance of ultracapacitors and the large energy storage capacity of lithium-ion batteries." Let's hope so.

[Source: Maxwell via The Energy Blog]

Maxwell is already pushing out its newly-released Heavy Duty Transportation module (HTM) 390-volt Boostcap ultracapacitor to industrial and transportation markets including for use in a number of hybrid city buses being rolled out in California. The HTM 390 has been designed to provide scalable, easy-to-integrate, energy storage and power delivery solutions of up to 1,170 volts for heavy duty electrical systems and hybrids. Margery Conner over at EDN had a test drive on one the new buses and was impressed with the smooth acceleration of the new hybrid powertrain.

Petrol-electric hybrid buses are being road tested in parts of California as a direct alternative to traditional diesel engines. While oil burners are far more fuel efficient than petrol vehicles, they have a bad reputation on the emissions front, especially with NOx emissions - a real concern in many large, Californian cities. The petrol-electric hybrid powertrain returns only slightly better fuel efficiency than a diesel engine - 5 mpg versus 3 to 5 mpg - but harmful emissions are hugely reduced. This has led ISE, the bus hybrid electro-mechanical subsystem contractor, towards utilising a series hybrid model where the engine drives a generator that produces electricity to run the electric motors driving the wheels. For Grover City, the flat terrain suits the petrol-electric hybrid, whereas in hilly Oakland, the hybrid buses will use fuel-cells instead of an electric motor.

Analysis: Using a series hybrid configuration is a good idea to allow the engine to be swapped out for different models or fuel-cells or the like. I think they should be giving a modern clean diesel configuration a go, though, to get the best of both worlds. Especially if they could run it on biodiesel.

Related:

• New 125-volt Boostcap ultracapacitor introduced by Maxwell Technologies
• DOE & USDA study proves biodiesel massively reduces dangerous emissions
• AFVI Show: Ways to save billions of gallons of fuel at the nation's airports

[Source: EDN.com]

ZENN Motors vehicle at the EDTA Conference last November

More details have emerged about EEStor's ambitious ultracapacitor electrochemical battery replacement technology. EEStor sees applications for their Electrical Energy Storage Units (EESU) in everything from hybrid-electric and pure-electric vehicles, to laptop computers, to utility-scale electricity storage. Based on barium-titanate powders, the units are supposed to dramatically outperform the best lithium-ion batteries on the market in terms of energy density, price, charge time, and safety. And since capacitors don't require chemical processes to store power, EEStor said in its patent, the materials the company uses are safer and more environmentally friendly.

Ultracapacitors store energy in an electrical field between two closely spaced conductors, or plates, upon which an electric charge builds when voltage is applied. Unlike traditional electrochemical batteries, ultracapacitors can completely store and release a charge quickly and indefinitely over many cycles. Where they don't compete though is energy storage; here lithium-ion batteries can store 25 times more specific energy - the amount of energy in a given unit of mass.

Most research into increasing the charge that can be stored by the plates has focused on ways to increase the surface area. Last year, the Massachusetts Institute of Technology said it was working on hugely increasing the plate surface area by researching plates made of microscopic nanotubes.

Up until now, ultracapacitors, have been used in conjunction with traditional batteries to more fully harness the regenerative energy created in sudden bursts by braking activity with their ability to release quick jolts of electricity. Their characteristics are ideal for maximising efficiency in stop-start city driving. Ultracapacitor manufacturer Maxwell Technologies has been able to capitalise on this strategy in their 125-volt BoostCap ultracapacitor module.

EEStor's EESU, a ceramic ultracapacitor with a barium-titanate dielectric, or insulator, is claimed to break free of the traditional limitations of small energy storage found in other ultracapacitors. Apparently they have achieved an exceptionally high specific energy and permittivity - the ability of an substance to store electrical energy in an electric field. Normally an ultracapacitor has a permittivity rating of 20 to 30, compared to the claimed EESU rating of 18,500 plus. As you can imagine, such claims have raised questions amongst experts who hold concerns that such ceramic materials can survive and function properly in vehicle applications.

In an interview with Technology Review, Jim Miller, vice president of advanced transportation technologies at Maxwell Technologies said, "We're skeptical, number one, because of leakage. Meaning, if you leave it parked overnight it will discharge, and you'll have to charge it back up in the morning."

In the same article, Andrew Burke, an expert on energy systems for transportation at University of California at Davis said, "I have no doubt you can develop that kind of [ceramic] material, and the mechanism that gives you the energy storage is clear, but the first question is whether it's truly applicable to vehicle applications."

ZENN Motor Company is reported to be getting first access to EEStor's EESU technology for use in their Low Speed Vehicles.

Maxwell Technologies meanwhile has just announced that they are forging ahead with their technology and have received a purchase order for 100,000 square meters / 1,076,400 square feet of proprietary ultracapacitor electrode material from a licensee, Shanghai Sanjiu Electric Equipment Co. This will allow Sanjiu Electric to launch a new ultracapacitor product line based on Maxwell's Cell Architecture for transportation, utility and industrial markets in mainland China.

Mr. Hong Yuan Shuai, Chairman and CEO of Sanjiu Electric parent company, the Ruihua Group, said that Sanjiu Electric has already produced and delivered a variety of prototype electric and hybrid buses, trucks and other vehicles powered by drive systems combining batteries and Maxwell BoostCap ultracapacitors for energy storage and regenerative braking.

Analysis: The EESU prospects are exciting, but I think Maxwell's use of ultracapacitors in regenerative breaking applications is probably a better choice for vehicular applications at this point. Where EEStor's products could open up a sizeable lead over the opposition though is in the area of military, direct-energy "ray-gun" weapons. Personally, I'll just stick with better fuel economy in stop-start traffic.

Related:

• Quick update on EEStor and ZENN Motors
• EDTA Conference: Secret effects of EESTOR ultracapacitor info from ZENN Motor CEO

[Source: Technology Review]