How a quest for a ten-fold improvement in batteries promises to make electric vehicles deliver on their remarkable potential.
The din that accompanied the birth of modern electric vehicles has quieted, despite a steady parade of new models and the ascent of gas prices to worrisome highs. The relative quiet is good news though, a sign that electric vehicles (EVs) are entering a critical period when the technology must evolve from exotic to everyday.
Recall that just a year an a half ago, waves of media buzz greeted the successive unveiling of Tesla’s Sportster, Nissan’s Leaf and GM’s Chevy Volt. Things are different now. You may have even missed that Ford unveiled a very Volt-like sedan at the Detroit Auto Show in January: the Fusion Energi, a plug-in hybrid due later this year, able to get the equivalent of 100 miles per gallon. Toyota is expected to begin selling an equally miserly plug-in version of its Prius hybrid in 2012 too.
The calmer reception and multiplying models are signs of vitality. Indeed, for battery-powered cars to deliver the transformative impact they promise-radically higher mileage, reduced oil dependency and cleaner skies-it’s vital that they go from extraordinary to ordinary as soon as possible.
No single technological advance could do more to make EVs “mainstream” than improved batteries. Not surprisingly, the quest to build a lighter, longer-lasting battery is reaching fever pitch at R&D labs around the world.
Lithium-ion cells were an early success. Improvements to the chemistry and manufacturing methods of Lithium-ion cells have led to reliable improvements in price and performance by about 6 to 8 percent per year. The gains have helped them edge ahead of other battery chemistries-such as lead acid, nickel cadmium or nickel metal hydride-to become the de facto standard for everything from portable power tools to EVs.
Steady as this advance is, it won’t revolutionize the price or performance of EVs soon enough, though. At that pace, the cost to outfit an EV with a battery pack-estimated today to add $10,000 to $15,000 to the price of Chevy Volt or Nissan Leaf-will fall by only half by 2020.
In the push to find radically better batteries, a leading contender is a material first conceived in the late 1990s when scientists theorized that combining lithium with oxygen could create a battery with unprecedented energy storage potential. A key feature of this approach is that the reaction “breathes” air, taking in oxygen when it discharges and releasing oxygen while recharging. Because the battery “borrows” these molecules from the air, fewer raw materials-and less weight-needs be built into the device.
This “Lithium-air” approach shows enormous theoretical potential to slash the weight and cost of battery packs. In 2009, IBM took a very long-term bet to see if it could realize this theoretical promise. The resulting project, dubbed Battery 500, aims to produce batteries able to propel an EV 500 miles on a single charge, roughly matching the range of a tank of gas. In short order, other private industry and university labs have joined the effort. The latest include Asahi Kasei and Central Glass-both specialists in the complex chemistry of Lithium-ion batteries-which came on board this month to develop custom Lithium-air technology.
Three years in, the results are tantalizing. Lithium-air shows the potential to store up to ten times the energy per weight of today’s commercial Lithium-ion batteries, opening the door to potentially game-changing applications. For instance, if a current EV can hold 100 miles worth of charge, a bank of Lithium-air cells promise to boost that capacity to 500 miles at similar weight.
To be sure, the scientific challenges facing the project remain daunting. After three years of work, the basic operation of rechargeable Lithium-air chemistry has been exhaustively characterized, showing the way ahead. But before Lithium-air cells can move from the laboratory to the car show room, researchers still must improve the cells’ long-term cyclability, speed-up the time needed to charge and discharge, and further drive down costs.
Still, the researchers have been knocking off these sorts of challenges so steadily that they hope to have a working a large-scale prototype within the next two years. Automotive commercialization would be further out, sometime between 2020 and 2030.
The stakes are high. Much better batteries would have a cascade of benefits in addition alleviating range anxiety. Improved storage would let EV owners recharge almost exclusively at night, when power supplies are cheapest and most plentiful. In turn, this would reduce drivers’ impulse to recharge away from home, thereby lowering the need for-and cost of- building out public recharging infrastructure.
Better batteries could help the grid too. Banks of stationary batteries could prevent blackouts by pitching in on rare occasions when generators or transmission lines are overloaded. Better energy storage could also help solve the greatest problem facing fast-growing solar panels and windmills: how to store and use renewable energy when the sun doesn’t shine, or the wind doesn’t blow.
From gearheads to everyday commuters, drivers of every sort are drawn to the allure and outright fun of driving speedy EVs. Someday, we hope, all their needs will be met, and we’ll recall the limited range of today’s EVs with the same nostalgia we hold for Model Ts. While the science behind building a 500-mile battery is daunting, the reward of a better driving on a healthier planet would be priceless.
Winfried Wilcke is Principle Investigator of the IBM Battery 500 Project
As a scientist at IBM Research – Almaden in San Jose, Calif., Dr. Winfried Wilcke is IBM’s Principle Investigator who initiated the Battery 500 coalition between IBM, several U.S. National Laboratories and international commercial partners. Dr. Wilcke received a doctorate in nuclear physics from Johann-Wolfgang Goethe Universitat, Frankfurt, Germany, and worked in physics, computer architecture and nanoscience.
