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We examine the potential economic implications of using vehicle batteries to store grid electricity generated at off-peak hours for off-vehicle use during peak hours. Hourly electricity prices in three U.S. cities were used to arrive at daily profit values, while the economic losses associated with battery degradation were calculated based on data collected from A123 Systems LiFePO4/Graphite cells tested under combined driving and off-vehicle electricity utilization. For a 16 kWh vehicle battery pack, the maximum annual profit with perfect market information and no battery degradation cost ranged from ~$140 to $250 in the three cities. If the measured battery degradation is applied, however, the maximum annual profit (if battery pack replacement costs fall to $5,000 for a 16 kWh battery) decreases to ~$10-$120. It appears unlikely that these profits alone will provide sufficient incentive to the vehicle owner to use the battery pack for electricity storage and later off-vehicle use. We also estimate grid net social welfare benefits from avoiding the construction and use of peaking generators that may accrue to the owner, finding that these are similar in magnitude to the energy arbitrage profit.

It seems that everyone is getting into the battery business, one of them will succeed in making a smaller, lighter and less expensive battery.  This development by ExxonMobil sound very promising. ExxonMobil Chemical and ExxonMobil's Japanese affiliate, Tonen Chemical have developed a thin film separator for use in lithium-ion batteries, that would enable production of batteries like those found in cell phones and laptops, to power cars and trucks. These new film technologies are expected to significantly enhance the power, safety and reliability of lithium-ion batteries, thereby helping speed the adoption of these smaller and lighter batteries into the next wave of lower-emission vehicles.

After safety, the longevity of the batteries in a plug-in hybrid is the greatest unknown. Can a plug-in hybrid’s battery pack retain the bulk of its energy capacity over 10 years of daily use and more than 4000 full-discharge cycles? (For a deeper look at the challenges facing plug-in hybrid batteries, see “Lithium Batteries Take to the Road”.)[ LINK: http://www.spectrum.ieee.org/sep07/5490 ] As Don Hillebrand of Argonne National Laboratory, in Illinois, said tartly, “Batteries are the showstopper.” Periodic demands from the grid, even for only a small fraction of the battery’s stored energy, would clearly affect the cells’ life span—but no one has data on how much. Another open issue is the development of creative financing models for replacement battery packs costing several thousand U.S. dollars even after mass production is achieved. Third-party battery leasing could be one answer, if combined with a secondary market for batteries whose performance has fallen below automotive levels. Carmakers, electric utilities, and large consumer-financing groups are quietly batting around these notions to see if they can build a financial model that makes sense for all three parties.

Stanford researchers have found a way to use silicon nanowires to reinvent the rechargeable lithium-ion batteries that power laptops, iPods, video cameras, cell phones, and countless other devices. The new version, developed through research led by Yi Cui, assistant professor of materials science and engineering, produces 10 times the amount of electricity of existing lithium-ion, known as Li-ion, batteries. A laptop that now runs on battery for two hours could operate for 20 hours, a boon to ocean-hopping business travelers.

Mobile phones, notebook computers, iPods—the boom in portable computing and communications devices is dependent on rechargeable lithium-ion batteries to deliver power. These batteries offer the highest energy density, allow laptops to function for useful amounts of time, and do not display a memory effect when compared to other types of rechargeable batteries. However, modern rechargeable batteries are still not truly satisfactory.