While electric vehicles are considered to be the future of motoring, they also have a legacy that dates back to 1837 when the first electric car was built. Unfortunately, their popularity did not last especially due to a decrease in the price of petrol and diesel hence petroleum driven cars dominated the roads. Today, technology has developed rapidly and the world continues to become more conscious of the environment resulting in the birth of a new era of e-vehicles. In this article we will look at how e-vehicles work and the new kinds of batteries and battery technology used to power electric vehicles.
An e-vehicle has an on-board battery as opposed to a fuel tank. An electricity supply is used to charge the battery which then stores and uses this energy to power its electric motor in order to set the wheels rolling. This means that electric vehicles do not need a gearbox and clutch or even an exhaust pipe making these vehicles extremely quiet and smooth to drive. A standard e-vehicle on a full charge can run over 400 km before it can be recharged. Although this is not the same distance that a tank of petrol can cover, it is still possible to accomplish most journeys in an electric vehicle.
Battery technologies for e-vehicles are rapidly advancing with research being conducted to help develop more efficient and reliable batteries that are capable of traveling for long distances. While most battery electric vehicles (BEV’s) use one type of battery, there are many other different types of batteries that can be used in electric vehicles. These include the nickel metal hydride (NiMH) and lead acid batteries. These are mature battery technologies that were originally used to power early e-vehicles like the General Motors EV1 but their use is now regarded obsolete.
The lead acid batteries commonly used in the conventional vehicles are quite inexpensive but have a poor specific energy of 34 Whlkg. In fact, the nickel metal hydride batteries have a better specific energy which is double that of lead acid batteries at 68 Whlkg hence are considered to be more superior. Electric vehicles that use the NiMH batteries are lighter which leads to lower energy cost for propelling e-vehicles or BEV’s. They also have a higher energy density compared to the lead acid types. The NiMH batteries though have a few drawbacks such as low charging efficiency compared to other types of batteries and they also have an issue with self-discharge especially in hotter environments.
Most modern e-vehicles use the lithium ion (Li-ion) batteries since they have a great longevity compared to other battery technologies. The Li-ion batteries have a specific energy of 140 Whlkg making it the most ideal battery for electric vehicles. These batteries also have an excellent capacity to retain energy with a 5 percent per month self-discharge rate.
There are so many reasons why one may consider buying an electric car instead of a conventional car but the most prominent one is the environment. E-vehicles generate less emissions besides being more energy efficient. Electric vehicles have fewer maintenance and operating costs compared to the conventional cars. A tank of gasoline costs way more than a full battery charge. Electric cars have few movable parts which means lower maintenance costs. Batteries for electric vehicles have become a critical component of the automotive industry but the Li-ion batteries are more dominant due to their low self-discharge rate as well as an excellent specific energy.