ADVANCE BATTERY STORAGE

For decades, battery storage technology has been a heavy weight on the back of scientific innovation. From cell phones to electric vehicles, our technological capabilities always seem to be several steps ahead of our ability to power them. Several promising new technologies are currently under development to help power the 21st century, but one small start-up looks especially well positioned to transform the way we think about energy storage.

Texas-based EEStor, Inc. is not exactly proposing a new battery, since no chemicals are used in its design. The technology is based on the idea of a solid state ultra capacitor, but cannot be accurately described in these terms either. Ultra capacitors have an advantage over electrochemical batteries (i.e. lithium-ion technology) in that they can absorb and release a charge virtually instantaneously while undergoing virtually no deterioration. Batteries trump ultra capacitors in their ability to store much larger amounts of energy at a given time.

EEStor’s take on the ultra capacitor — called the Electrical Energy Storage Unit, or EESU — combines the best of both worlds. The advance is based on a barium-titanate insulator claimed to increase the specific energy of the unit far beyond that achievable with today’s ultra capacitor technology. It is claimed that this new advance allows for a specific energy of about 280 watts per kilogram — more than double that of the most advanced lithium-ion technology and a whopping ten times that of lead-acid batteries. This could translate into an electric vehicle capable of traveling up to 500 miles on a five minute charge, compared with current battery technology which offers an average 50-100 mile range on an overnight charge. As if that weren’t enough, the company claims they will be able to mass-produce the units at a fraction the cost of traditional batteries.

“It’s a paradigm shift,” said Ian Clifford of ZENN Motor Co., an early investor and exclusive rights-holder for use of the technology in electric cars. “The Achilles’ heel to the electric car industry has been energy storage. By all rights, this would make internal combustion engines unnecessary.”

But this small electric car company isn’t the only organization banking on the new technology. Lockheed-Martin, the world’s largest defense contractor, has also signed on with EEStor for use of the technology in military applications. Kleiner Perkins Caufield & Byers, a venture capital investment firm who counts Google and Amazon among their early-stage successes, has also invested heavily in the company.

PEM FUEL CELLS

Polymer electrolyte membrane (PEM) fuel cells—also called proton exchange membrane fuel cells—deliver high-power density and offer the advantages of low weight and volume, compared with other fuel cells. PEM fuel cells use a solid polymer as an electrolyte and porous carbon electrodes containing a platinum catalyst. They need only hydrogen, oxygen from the air, and water to operate and do not require corrosive fluids like some fuel cells. They are typically fueled with pure hydrogen supplied from storage tanks or on-board reformers.

PEM Technology:

Polymer electrolyte membrane fuel cells operate at relatively low temperatures, around 80°C (176°F). Low-temperature operation allows them to start quickly (less warm-up time) and results in less wear on system components, resulting in better durability. However, it requires that a noble-metal catalyst (typically platinum) be used to separate the hydrogen’s electrons and protons, adding to system cost. The platinum catalyst is also extremely sensitive to CO poisoning, making it necessary to employ an additional reactor to reduce CO in the fuel gas if the hydrogen is derived from an alcohol or hydrocarbon fuel. This also adds cost. Developers are currently exploring platinum/ruthenium catalysts that are more resistant to CO.

PEM Fuel Cell Applications:

PEM fuel cells are used primarily for transportation applications and some stationary applications. Due to their fast startup time, low sensitivity to orientation, and favorable power-to-weight ratio, PEM fuel cells are particularly suitable for use in passenger vehicles, such as cars and buses.

Disadvantages of Fuel Cell:

A significant barrier to using these fuel cells in vehicles is hydrogen storage. Most fuel cell vehicles (FCVs) powered by pure hydrogen must store the hydrogen on-board as a compressed gas in pressurized tanks. Due to the low-energy density of hydrogen, it is difficult to store enough hydrogen on-board to allow vehicles to travel the same distance as gasoline-powered vehicles before refueling, typically 300–400 miles. Higher-density liquid fuels, such as methanol, ethanol, natural gas, liquefied petroleum gas, and gasoline, can be used for fuel, but the vehicles must have an on-board fuel processor to reform the methanol to hydrogen. This requirement increases costs and maintenance. The reformer also releases carbon dioxide (a greenhouse gas), though less than that emitted from current gasoline-powered engines.