What If Electric Cars Were Better?
To
get there, many experts agree, a major shift in battery technology may be
needed. Electric vehicles such as the all-electric Nissan Leaf and the
Chevrolet Volt, a plug-in hybrid from GM, rely on larger versions of the
lithium-ion batteries that power smart phones, iPads, and ultrathin laptops.
Such gadgets are possible only because lithium-ion batteries have twice the
energy density of the nickel–metal hydride batteries used in the brick-size
mobile phones and other bulky consumer electronics of the 1980s.
Using lithium-ion batteries,
companies like Nissan, which has sold 20,000 Leafs globally (the car is priced
at $33,000 in the U.S.), are predicting that they've already hit upon the right
mix of vehicle range and sticker price to satisfy many commuters who drive
limited distances.
The
problem, however, is that despite several decades of optimization, lithium-ion
batteries are still expensive and limited in performance, and they will
probably not get much better. Assembled battery packs for a vehicle like the
Volt cost roughly $10,000 and deliver about 40 miles before an
internal-combustion engine kicks in to extend the charge. The battery for the
Leaf costs about $15,000 (according to estimates from the Department of Energy)
and delivers about 70 miles of driving, depending on various conditions.
According to an analysis by the National Academy of Sciences, plug-in hybrid
electric vehicles with a 40-mile electric range are "unlikely" to be
cost competitive with conventional cars before 2040, assuming gasoline prices
of $4 per gallon.
Estimates of the cost of
assembled lithium-ion battery packs vary widely. The NAS report put the cost at
about $625 to $850 per kilowatt-hour of energy; a Volt-like car requires a
battery capacity of 16 kilowatts. But the bottom line is that batteries need to
get far cheaper and provide far greater range if electric vehicles are ever to
become truly popular.
