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Most people call them EVs or electric cars – cars and crossover SUVs powered by strong electric motors. They get their juice from big packs of on-board batteries that are rechargeable. The proper name is battery-electric vehicle, or BEV. That’s an acronym that properly describes the full power and fuel system.
Consumers can choose from about a dozen in the U.S. market today, and new models are added with some regularity.
All operate by directing power to the driven wheels through a single-speed transmission. They can have more than one motor, as do top-of-the-line Tesla Model S and Model X BEVs. Those have two motors, one driving the front wheels, the other driving the rear wheels.
The energy to keep the motor or motors turning is stored on the BEV in a rechargeable battery pack. It usually is based on a lithium-ion chemistry and in a battery-electric vehicle is much larger than the batteries in conventional hybrids or plug-in hybrids – the “other” member of the plug-in vehicle (PEV) family.
The pluses of a BEV include a relatively simple powertrain, which has few moving parts, is relatively maintenance-free, provides tons of torque – the force that gets a vehicle moving – for quick acceleration, and has no tailpipe emissions. A battery-electric vehicle also can be charged at a large and still-growing number of public charging stations or while parked at home.
Electric motors also are about three times more efficient than internal combustion engines at converting electricity into power at the wheels. That reduces the overall emissions impact of generating the electricity they use when compared to the emissions created in the production and use of gasoline or diesel fuel.
On the downside, BEVs differ from other electrified vehicles in that that they are entirely dependent on their batteries. They need to be recharged regularly and usually for several hours, or more.
Because the batteries are expensive and heavy, there are limits on how big a battery pack can efficiently and economically be loaded into a BEV. That limits the vehicles’ range. With the exception of Tesla’s Model S and Model X, few in the market right now can exceed 110 miles on a single charge. Things may change, though. General Motors is promising a 200-mile BEV, the Chevrolet Bolt, by fall of 2016. And Nissan plans to follow with a 200-mile version of its Leaf BEV when the next-generation Leaf is released for the 2017 model year.