Fascinatingly, the real answer to this question is that nobody seems to know. Even the world's most brilliant scientists admit that they don't know how electricity works or why it works; they simply know it does work. That philosophical concept aside, an electric vehicle uses batteries to power an electric motor that, in turn, propels the vehicle. Vehicles that have these characteristics are alternatively called pure electric vehicles.
Electric cars produce no tailpipe emissions and the miniscule amounts of "evaporative emissions" they produce come from the evaporation of their lubricants. The vehicle's batteries must be recharged from the "electrical grid," which in practice means a power hook-up at your home and/or office. Many electric vehicles also use "regenerative braking," a procedure that generates electricity when the car is slowing down or coasting.
Electric drive systems are virtually nonpolluting and extremely energy efficient. Although only about 20 percent of the chemical energy in gasoline is converted into useful work at the wheels of an internal combustion vehicle, some 75 percent or more of the energy from a battery reaches the wheels of an EV. This helps make up for the fact that current battery technology does not allow the storage of nearly as much energy as is contained in the gas tank of a conventional car.
A key advantage of an electric motor is its ability to provide power and torque at almost any engine speed. In contrast, internal combustion engines produce their peak horsepower and torque in relatively narrow ranges of engine speed, hence an elaborate system of gears (in common parlance, a "transmission") is required to keep the engine operating in
\*/ A pure electric vehicle uses on-board sources of electricity stored in a battery or battery bank as power, and it must be plugged into a source of electricity to recharge its batteries. It is otherwise known as a battery electric vehicle or BEV.
its sweet spot while the car travels at varying velocities. Electric motors provide nearly peak power even at very low revolutions per minute (rpm), and this gives electric vehicles strong acceleration performance from a stop.
Just as it was in 1910, it is the quality of the batteries that determine the cost, performance, and essential viability of EVs. The EVs from the major manufacturers that came to market and then left the market as the millennium turned used lead-acid batteries, the same type of battery that electric cars used at the turn of the previous century. By the way, that same type of battery powers the starter motor and radio in your current car. Now there are several new types of automotive batteries available and under development, including advanced lead-acid batteries, nickel-metal hydride, lithium-polymer, and lithium-ion. Still, even the best of these new batteries can hold only a tiny faction of the energy "stored" in a gallon of gasoline in the same space. What this means is that driving range is still a major issue.
This could be addressed at least to some extent by the ability to quickly recharge the on-board batteries. However, even in the best of today's systems, recharging still takes a considerable amount of time, much longer than filling up your car's gas tank. On the positive side, relatively simple home recharging systems are available. They can serve as a convenient way to fill batteries with power every night without ever having to go to a filling station. But while that can be a boon, recharging sites away from home are still scarce.
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