You don't have to dig too deep into the world of alternative fuel vehicles to realize that one of the biggest hurdles facing expansion of this sector has been the battery. While at the heart of the electric vehicle (EV) and hybrid world, by the same token, the lithium-ion battery, expected to surpass use of the nickel-metal-hydride version, presents some clear challenges to growth of the alternative fuels industry.
Glen Bower, automotive faculty advisor, University of Wisconsin, Madison, explains that while technological advances in batteries have focused on battery chemistry and downsizing the semi-conductor devices used to switch electric power, these now advanced batteries contain lithium as one of their major components. That lithium is being coupled with several different compounds, most often cobalt and iron-phosphate.
Those new battery types can out-perform their predecessors, but Bower points out that they also require highly sophisticated monitoring and active management circuitry. Art Wheaton, auto industry expert, Industrial and Labor Relations School, Cornell University, Buffalo, N.Y. takes such concerns even further, raising the question of whether the current generation of batteries is even in contrast to the green image of EVs. Electric batteries require rare and exotic materials such as lithium. Wheaton warns that such materials are potentially as problematic as the current dependence on foreign oil, adding that the U.S. could potentially swap its oil dependcy for reliance on a different foreign commodity.
But there are growing signs that green energy investors are taking note of the need to address many of the concerns surrounding battery technologies. Formerly only concentrating on improving the range of battery-operated vehicles, the new wave of research worldwide is targeting alternatives to lithium, storage capacity, environmental impact and other factors with battery technologies designed to address current concerns over advanced lithium ion batteries. Here are just a few noteworthy examples:
Electrodes from Renewable Materials
Getting at the heart of the matter—scarce materials—experts in nanotechnology at Uppsala University, Uppsala, Sweden, are working to produce batteries from renewable, readily available materials. That's right, we could see electrodes from green sources like algae cellulose. While early attempts certainly address the cost factor and are easy on the environment, not surprisingly the resulting batteries can’t hold a torch in the power department. Undaunted, researchers continue to work toward increasing energy density while further developing renewable and readily available batterycomponents, like electrodes made from algae cellulose coated with a conducting polymer.
Superthin Batteries are Super Charged
Closer to home, researchers at MIT are looking at using carbon nanotubes for electrodes on so-calle advanced batteries for the automotive industry. Relying on chemical reactions for performance, much like a convetional battery does, these batteries differ in that they are able to store energy without using any chemical reactions. Part of the focus at MIT has been on addressing the need for a surge of energy during engine start-up and similar tasks, and having the battery able to immediately respond, thanks to the carbon nanotubes, then continue to provide high-power energy storage. It's understood that electrochemical capacitors discharge batteries quickly to meet needs for power surges, while the traditional-battery type storage means high power capability. Research like that at MIT, looking at options across the spectrum, has prompted companies like GM to look at a lineup of vehicles utilizing a broad range of battery types.
Lithium Air Batteries Need Power Burst
Researchers at IBM’s Nanoscale Science and Technology division are concentrating on developing a battery to answer the needs of EVs and hybrids. In addition to scarce resources, one of the looming issues for electric and hybrid cars has been the lack of infrastructure to support necessary charging, a costly proposition. IBM’s answer? Instead of building infrastructure, put all the focus on building a better, bigger battery. Researchers there are working on a lithium-air battery that would store energy in an amount comparable to filling a conventional gasoline tank. The holdback so far, however, is that lithium-air batteries are great for things requiring a lot of energy but not necessarily so when the need is to go through a burst of energy in one bite. The answer may be to couple the lithium-air battery with smaller lithium-ion batteries, achieving that quick acceleration.
Doubling Capacity of Lithium-ion Batteries
By swapping graphite for silicon as an electrode material, two start-ups have announced they'll make lithium-ion batteries that can hold twice as much energy as they currently do. Both companies—-Nexeon, in Abingdon, England, and Amprius, in Menlo Park, Calif.—-say they expect their silicon electrode technology to hit the market in the next couple of years. Meanwhile, Nanosys has developed a solution to using silicon compounds in lithium batteries. It's been long known this could dramatically improve energy density, or the amount of energy held per kilogram of battery, but volumetric expansion, whenever was a problem. Batteries from Nonsys use silicon compounds without the volumetric expansion problem, claiming doubled battery capacity. The company says it hopes to fulfill the U.S. Department of Energy target to bring the cost of lithium-ion batteries down to $250/kWh while increasing capacity to 300 miles per charge.
Super Thin Meets Super Versatile
Across the pond, engineers at Volvo Corporation are concentrating on two classes of batteries: one for EVs and one for hybrids. But both are being designed to go where few batteries have gone before, namely into the door or into the hood, a testament to how thin they truly are. Batteries being developed here are so thin, in fact, that such batteries can have energy spread over a large surface area, opening up endless possibilities for tapping battery power where hurdles had previously existed.