Thursday, March 12, 2009

Batteries Can Power Electric Cars

Our society has constantly been trying to reduce the air pollution in our atmosphere and one way is the use of electric cars. Many of the electric cars that have already been marketed use similar lead-acid batteries that gasoline-powered vehicles use to operate the starter motor, and many batteries need to be connected together to produce the power that is needed (Baird). Future electric cars might use nickel-cadmium, nickel-metal hydride, and lithium-based batteries (Baird).

Although battery-powered vehicles might reduce pollution, there are many practical difficulties that discourage their use: high cost, the short driving range before the batteries need recharging, the length of the battery recharge period, and the heaviness of the batteries (Baird). Secondly, electric cars are not entirely free of pollution. “Some pollution is emitted into the environment if the electricity required to charge the batteries is generated from fossil fuel combustion” (Baird). Also, lead pollution from the manufacture, handling, disposal, and recycling of lead-acid batteries would cause a rise in lead emissions into the environment according some economists and engineers.

Now several automobile manufacturers offer “hybrid-electric” cars with electric motors that run from power stored in batteries. For example, the Toyota Prius has a small gasoline engine that charges the battery and supplements its power at high road speeds (Baird). Also, “the energy lost by a conventional gasoline engine during idling is eliminated since the electric motor is switched off at these times” (Baird). The battery is recharged without the use of fuel during braking by using the energy of the motion of the vehicle that is usually lost as heat, which occurs in all hybrid-electric vehicles (Baird). Because of these features, the efficiency of the electric motor, and its lack of pollutant emissions, these cars are much more energy-efficient and cleaner than normal gasoline-powered cars.

Unfamiliar Terms:
1) Combustion: rapid oxidation accompanied by heat and, usually, light.
2) Nickel-cadmium: The principal advantages of NiCd over other rechargeable types is lower weight for a given quantity of stored energy, good charging efficiency, small variation in terminal voltage during discharge, low internal resistance, and non-critical charging conditions. They can be used in place of regular batteries in most applications.
3) Nickel-metal hydride: A nickel-metal hydride battery, abbreviated NiMH, is a type of rechargeable battery similar to a nickel-cadmium (NiCd) battery but using a hydrogen-absorbing alloy for the negative electrode instead of cadmium. As in NiCd batteries, the positive electrode is nickel oxyhydroxide (NiOOH). A NiMH battery can have two to three times the capacity of an equivalent size NiCd. However, compared to the lithium-ion battery, the volumetric energy density is lower and self-discharge is higher.
4) Lithium: Lithium hydride is used as a source of hydrogen; lithium hydroxide is used as an additive in storage batteries and to absorb carbon dioxide.

This excerpt from from Chemistry in Your Life is exactly why chemistry is so important to understand. Understanding chemistry can help us improve the future so that we can have a healthy world to live in. It is so amazing to me how we have such complex techonology that we can create different types of car batteries to decrease pollution. I believe it is so important to recognize that pollution is a huge problem in our world today, because it jeopardizes our health. Businesses are so concerned with making money that they don't care about the ethics involved. Pollution is a major concern in our society today, but I do believe we are on the right track to realizing we need to take care of the world we live in.

Baird, Colin. Chemistry in Your Life. New York: W.H. Freeman and Company, 2006. 461-62.

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