Advantages and Disadvantages of EVs

The most obvious advantage of electric car batteries is that they don't produce the pollution associated with internal combustion engines. However, they still have environmental costs. The electricity used to recharge EV batteries has to come from somewhere, and right now, most electricity is generated by burning fossil fuels. Of course, this produces pollution. But how does the pollution produced by burning fossil fuels to recharge electric car batteries compare to the pollution produced by internal combustion engines? According to the Electric Vehicle Association of Canada, or EVAC, even EVs recharged from coal-powered electric generators cut carbon emission roughly in half. EVs recharged from cleaner forms of electrical power generation, such as hydropower and nuclear plants, can reduce carbon emissions to less than one percent of those currently produced by internal combustion engines. So, even in the worst case scenario, cars operated by EV batteries are cleaner than gas-powered cars.

Charging cable for an electric car
Karen Keczmerski/iStockphoto
It seems like batteries are a practical way of powering a vehicle. What are the advantages and disadvantages?

Another important advantage of battery-powered motors over gas-powered engines is the lower cost of the fuel -- that is, electricity for EVs and gas for the internal combustion engines. The United States Department of Energy has calculated that a typical EV can run for 43 miles on a dollar's worth of electricity. Only a substantial drop in the cost of gasoline could give gas-powered cars anywhere near such a low cost per mile.

Yet another advantage of these rechargeable batteries is that they recycle well. Almost 100 percent of these batteries can be recycled, which keeps old batteries from becoming a disposal problem.

The major disadvantage of battery-powered cars, as we mentioned in the last section, is the time required to recharge the batteries. With lithium-ion battery technology, a fully charged EV can travel a distance comparable to an internal combustion engine vehicle with a full tank of gas, but it still needs to be placed on a recharger at the end of that time. At present, this means a drained EV will be out of service for several hours before it's fully recharged. Of course, this is a serious disadvantage. In the future, faster recharging technology may become available, but in the near term, electric cars won't be the vehicles of choice for long trips. Even so, most driving is done relatively close to home and for this reason, battery power will serve as well as gasoline power. A possible solution to the recharging situation may be battery-replacement stations, where instead of recharging your EV you can simply swap your drained battery for a fully charged one. This system would allow batteries to be recharged outside of vehicles and would greatly reduce the amount of time required to get an EV up and running again after its battery is fully discharged.

Another disadvantage of electric car batteries is their weight. Because they need to do more than traditional car batteries, electric car batteries need to be linked together into arrays, or battery packs, to provide additional power. These collections of batteries are heavy. The lithium-ion battery pack in a Tesla Roadster weighs about 1,000 pounds (453.6 kg). That's a lot of weight to carry and it can greatly reduce the car's range. However, the designers of the Roadster have offset this battery weight with a light frame and body panels. The entire car only weighs 2,690 pounds (1220.2 kg) -- not terribly heavy when you consider that more than a third of that weight is battery.

Given the importance of the battery to an electric car, you might wonder what will happen as that battery grows older. How long will it be able to power the car? And when it finally dies, can it be replaced or is it simply more economical to buy a new car? Read on to find out.

­