Types of Electric Vehicle Batteries
What is an electric battery?
A battery is a device for storing chemical energy and converting that chemical energy into electricity. Studying the construction of the battery we find that a battery is made up of one or more electrochemical cells, each of which consists of two half-cells or electrodes. One half-cell, called the negative electrode, has an overabundance of the tiny, negatively charged subatomic particles called electrons. The other, called the positive electrode, has a deficit of electrons. When the two halves are connected by a wire or an electrical cable, electrons will flow, as a nature, from the negative electrode to the positive electrode. Thus is the flow of electrons electricity. Thus, the energy of these moving electrons can be harnessed to do work like running a motor, for example. As electrons pass to the positive side, the flow gradually slows down and the voltage of the electricity produced by the battery drops. Eventually, when there are as many electrons on the positive side as on the negative side, the battery is considered ‘dead’ and is no longer capable of producing an electric flow.
Categories of Batteries
The electrons are generated by chemical reactions, and there are many different chemical reactions that are used in electric vehicle batteries. For example, the alkaline batteries commonly used in flashlights and television generate electricity through a chemical reaction involving zinc and manganese oxide. Most alkaline batteries are considered to be a disposable battery. Once they go dead, they’re useless and should be recycled.
But in case of electric vehicles, we need them to be rechargeable, so they don’t require constant replacement. In a rechargeable battery, electrical energy is used to reverse the negative and positive halves of the electrochemical cells, restarting the electron flow. A kind of flip-flop till all the electrical energy is used continuously. So this way, they can be used for a longer time by recharging.
Kind of Batteries Identified for the Electric Vehicles
Electric Vehicle (EV) manufacturers have identified three types of rechargeable battery as suitable for electric car use. Those types are lead-acid batteries, nickel metal hydride (NiMH) batteries, and lithium-ion (Li-ion) batteries
Lead-acid batteries were invented more than 150 years ago and are the oldest form of rechargeable battery still in use. They’ve been used in all types of cars, including electric cars, since the 19th century. Lead-acid batteries are a kind of wet cell battery and usually contain a mild solution of sulphuric acid in an open container. So it is the combination of lead electrodes and acid used to generate electricity in these batteries. The major advantage of lead-acid batteries is that, after having been used for so many years, their technicalities is clear to us and cheap to produce. However, they do produce dangerous & hazardous gases while being used and if the battery is overcharged there’s a risk of explosion.
Nickel Metal Hydride Batteries came into commercial use in the late 1980s. They have a high energy density — that is, a great deal of energy can be packed into a relatively small battery — and don’t contain any toxic metals, so they’re easy to recycle.
Lithium-ion batteries, which came into commercial use in the early 1990s, have a very high energy density and are less likely than most batteries to lose their charge when not being used, a property called self discharge. Because of their light weight and low maintenance requirements, lithium-ion batteries are widely used in electronic devices such as laptop computers. Some experts believe that lithium-ion batteries are about as close as science has yet come to developing a perfect rechargeable battery, and this type of battery is the best candidate for of the near future. A variation on lithium-ion batteries, called lithium-ion polymer batteries, may also prove valuable to the future of EVs. These batteries may eventually cost less to build than lithium-ion batteries; however, at the present time, lithium-ion polymer batteries are prohibitively expensive.
Perhaps the greatest problem associated with electric car batteries is recharging them!! How do you charge an electric car battery? Where do you can charge an electric car battery? Can you do it yourself? Can you do it at home? What should be the infrastructure for battery charging?
Also refer my earlier note in this blog “When Will Electric Cars Become A Common Sight On The Roads”? where I have highlighted other points on this subject.