August 20, 2012

Complete Guide: The Different Battery Types and Technologies

An electrical battery is one or more electro-chemical cells that convert stored chemical energy into electrical energy. The first battery is 2,000 years old and was discovered in 1938 by Wilhelm Konig in Iraq.

Since the invention of the first modern battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836 by John Frederic Daniell, batteries have become a common power source for many household and industrial applications.

According to a 2005 estimate, the worldwide battery industry generates US $48 billion in sales each year,with 6% annual growth.

Batteries can be broken down into three categories: Primary, Secondary, and Specialist.

Primary

Zinc/Carbon Battery [AA, C and D dry cell batteries]
It has Zinc and Carbon as electrodes and an acidic paste as the electrolyte.

Alkaline Battery [Duracell and Energizer batteries
It uses Zinc and Manganese dioxide in powdered form as the electrodes and an Alkaline, like Potassium hydroxide, as the electrolyte.

Lithium Cell [cameras, calculators and pacemakers]
Different Lithium cells exist because of its stability and low reactivity with a number of cathodes and non-aqueous electrolytes. The most common electrolytes are organic liquids.

Zinc/Air Cells [ pagers, hearing aids]
Amalgamated Zinc powder and Oxygen (Air) are the electrodes and Potassium Hydroxide is used as the electrolyte. This cell is lightweight, environmentally friendly and has a relatively low cost.

Secondary



Lead Acid Battery [automobiles, boats, motorcycles] ] 
Lead and Lead oxide are used as electrodes with a very strong acidic electrolyte. This is rechargeable. The modern variation is known as Gel Cell, where the electrolyte is in a gelatin form.

Nickel/Cadmium Cells (NiCd) [digital cameras, laptops, calculators] 
Cadmium and Nickel are used as electrodes and aqueous Potassium Hydroxide is used as the electrolyte. It is a rechargeable battery, but it is prone to the memory effect, where the cell retains the characteristics of the previous cycle. The image on the right shows the inside of a NiCd battery, showing the actual cells that make up the battery.

Nickel Metal Hydride (NiMh) [laptops, camcorders, mobile phones, power tools]
Rare-earth or nickel alloys with many metals are used as the electrodes and Potassium Hydroxide is used as the electrolyte. This is rechargeable and is also prone to the memory effect, but less so than the Ni Cad cells. The image on the right is of a NiMH laptop battery showing the actual cells inside.

Lithium Ion Cells (Li-ion) [laptops, mobile phones] 
Carbon compound and Lithium Oxide are used as electrodes and organic solvents are used as the electrolyte. Has a very good power to weight ratio, rechargeable, and no memory effect. This is the battery technology used on Limewit.com's laptop and netbook batteries.

Lithium Ion Polymer Cells [PDAs, handhelds, micro-models, MP3 players]
The electrolyte used is a polymer. It resembles a plastic like film which does not conduct electricity, but allows the exchange of ions. The dry polymer design offers simplifications with respect to fabrication, ruggedness, safety and thin-profile. There is no danger of flammability because no liquid or gelled electrolyte is used.

Specialist

Silver/Zinc Cells [aeronautical and defense applications: torpedoes, guiding systems]
Silver-zinc cells provide the basis for both primary and secondary (rechargeable) batteries. In cells for primary batteries, the anode is zinc and the cathode is silver oxide. In cells for secondary batteries, the anode is zinc oxide and the cathode is silver. In both cases, the electrolyte is based on potassium hydroxide. The output voltage is 1.65 V. 

Sodium/Sulphur Cells [electric vehicles, aerospace applications such as satellites] 
Uses molten Sodium and Sulphur as electrodes and ceramic beta alumina as the electrolyte. This has been studied extensively for electric vehicles because of its inexpensive materials, high cycle life, and high specific energy and power. 

The problems with this cell are that the temperature has to be kept at 350C to keep the Sulphur in liquid form. This is achieved through insulation or heating through the cells own power. This lowers the energy density. The electrolyte is brittle and develops microfissures. Thus the liquid sodium and sulfur come in contact—with explosively violent results.

Edited by Limewit Tech Blog
Photos courtesy of Limewit.com and AESC

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