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Hurdles and Outlook for Batteries in Electric Vehicles

Posted on the 03 August 2012 by 2ndgreenrevolution @2ndgreenrev

Hurdles and Outlook for Batteries in Electric VehiclesEven if you’re not much of a car buff, you probably have the sense that traditional, internal combustion vehicles generally have the edge in cost over electric vehicles (EVs). And you’d be right. As Stephanie Yin notes in her article, “The Long, Winding Road to Advanced Batteries for Electric Cars,” battery technology has come a long way, but still faces several major obstacles before it can truly compete with oil. Several of these obstacles cited by Yin and others are described below.

Obviously, the biggest impediment to any form of alternative energy is cost. A 2011 Stanford University study states that the general cost target for 40-mile range battery packs by 2012 was $500 per kWh, whereas the current cost hovers between $800 and $1,000 per kWh. The corresponding cost objective for 2016 is $300 per kWh. Prices of battery packs may be reduced with the continued development of advanced software that can better predict battery life and safety, and perhaps lead to scientific breakthroughs (one such example mentioned by Yin is the development of lithium-oxygen batteries).

Energy density is the next biggest stumbling block for prolific battery use. According to a 2011 study by Yuan Zhong (also from Stanford), doubling the target range of EVs to 310 miles in the next decade is a generally accepted goal by most automakers. Compared to gasoline, the energy density of lithium-ion batteries is very low–180 Watt-hours (Wh)/kg for lithium-ions versus 3,000 Wh/L for gasoline (one kilogram weighs roughly the same as one liter).

However, even if cost and energy density are resolved, the inconvenience of lengthy charging times will always be a turnoff to consumers. Currently, 30 minutes is about the fastest an EV can be topped off.  To further reduce charging time, enhanced cooling systems and issues regarding battery damage from high-voltage charging must be addressed.

Car makers must also focus on reducing battery degradation. According to a National Renewable Energy Laboratory presentation, EVs and plug-in hybrid batteries retain on average 80 percent of their charge after eight years of use. However, as Zhong notes that a battery’s lifespan ends at 70 percent capacity, EVs would probably need new battery packs after about 10 years. Uncertainty over long-term battery life is one reason why leasing companies give EVs low residual values after only a few years.

With staunch government support in several countries and growing consumer demand, many are hopeful these issues will addressed in the next decade. However, the mingling of sustainability with battery design may have to wait until future generations.

Image by Argonne National Labortory

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