Report submission 1 & 2

Batteries

A battery is an electrochemical device that stores chemical energy which can be converted into electrical energy. A battery is properly applied to a group of two or more electrochemical cells connected together. Single cell and multi cell devices are called batteries.

There are two general types of batteries, the primary battery and the secondary battery. The primary battery delivers current as the result of a chemical reaction; this makes the battery not rechargeable. Only one continuous discharge can be obtained from the chemicals placed in it during manufacture, then the primary battery must be replaced. The secondary battery is rechargeable because it delivers current as the result of a chemical reaction. A charging current flows through its terminals opposite to the current flow during discharge. http://0-www.accessscience.com.library.hct.ac.ae/content.aspx?searchStr=batteries&id=075200.  Both primary and secondary cells are manufactured in many sizes and shapes, from the miniature coin or button shaped battery, which means it has a diameter greater than its height. For the best performance, the battery must be constructed for its particular application. Automotive and aircraft batteries are secondary batteries that have relatively thin positive and negative plates. The cell is the basic electrochemical unit. It has three parts, a negative electrode, a positive electrode and an electrolyte solution. The electrodes are metal rods that are used to receive electrical energy, store electrical energy chemically, and deliver electrical energy as a result of the reactions. The electrolyte is a chemical compound, salt, acid, or base, that when dissolved in a solvent, forms a solution that becomes an ionic conductor of electricity. Some cells have no aqueous electrolyte; for example, when alcohol is used as the solvent. During the charging of a secondary cell, the negative electrode becomes the cathode and the positive electrode becomes the anode.

Standby batteries are secondary batteries that use thick plates and thick separators to provide long life. Size and weight in all types of batteries continue to be made through use of new materials and methods of construction. Batteries are probably the truest source of power known. Further growth may result from significant increases in system operating voltage, such as from 12 V to 24 V or 48 V, which can provide much higher power with less weight. Primary batteries are used as a source of power where the electrical charging power is not readily available; convenience is of major importance, such as in a hand or pocket flashlight. Secondary batteries are used as a source of power where the battery is the primary source of power; the battery is used to supply large, short time repetitive power requirements as in automotive and aircraft batteries; long periods of low current rate discharge followed by recharge are required as in marine buoys and lighthouses. The life expectancy of a battery depends on its design and materials. Automotive batteries may last as long as 18 months in hot climates and 10-12 years in cold climates. Industrial batteries have a 10-20 year service life. Generally the most costly cells have the longest life service. Energy and power are often used as means of distinguishing batteries from each other. http://0-www.accessscience.com.library.hct.ac.ae/content.aspx?searchStr=batteries&id=YB090153 . Nowadays in batteries for vehicles the important metrics include energy representing how much useful work can be performed, power representing how quickly this energy can be released, cycle life representing how many times the battery can be charged, calendar life representing how many years the battery can last before its capacity fades, self discharge representing how many days the battery holds its charge, and the capacity represents how much electricity can be obtained from the battery. http://0-www.accessscience.com.library.hct.ac.ae/content.aspx?searchStr=batteries&id=YB090153 . A solid state battery is a battery in which both electrodes and the electrolyte are solids; their study belongs to an area of science known as solid state ionics.

In the 21^st century I guess that everything works with chargeable batteries which have a longer life than the old batteries. New batteries give more power than before and are more useful. The most important thing is that every new battery has great safety so as not to harm children or even older people, but at the same time it’s more powerful.

Bibliography

M. Stanley Whittingham, "Solid-state battery," in AccessScience, ©McGraw-Hill Companies, 2008, http://www.accessscience.com from http://0-www.accessscience.com.library.hct.ac.ae/content.aspx?searchStr=batteries&id=634700

 

Donald L. Anglin, Donald R. Sadoway, "Battery," in AccessScience, ©McGraw-Hill Companies, 2008, http://www.accessscience.com from http://0-www.accessscience.com.library.hct.ac.ae/content.aspx?searchStr=batteries&id=075200

 

Venkat Srinivasan, "Advanced batteries," in AccessScience, ©McGraw-Hill Companies, 2009, http://www.accessscience.com from http://0-www.accessscience.com.library.hct.ac.ae/content.aspx?searchStr=batteries&id=YB090153

 

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