In electronics, a battery or voltaic cell is a combination of one or more electrochemical Galvanic cells which store chemical energy that can be converted into electric potential energy, creating electricity. Since the invention of the first Voltaic pile in 1800 by Alessandro Volta, the battery has become a common power source for many household and industrial applications, and is now a multi-billion dollar industry.

The name "battery" was coined by Benjamin Franklin for an arrangement of multiple Leyden jars (an early type of capacitor) after a battery of cannon. Common usage has evolved to (inaccurately) include a single electrical cell in the definition.

The first battery was invented in 1800 by Alessandro Volta. Although it was of great value for experimental purposes, its limitations made it impractical for large current drain. Later batteries, starting with John Frederic Daniell's wet cell in 1836, provided more reliable currents and were adopted by industry for use in stationary devices, particularly in telegraph networks where, in the days before electrical distribution networks, they were the only practical source of electricity. These so-called wet cells used liquid electrolytes, and were thus prone to leaks and spillage if not handled correctly. Some, like the gravity cell, could only function in a certain orientation. Many used glass jars to hold their components, which made them fragile. These practical flaws made them unsuitable for portable appliances. Near the end of the 19th century, the invention of dry cell batteries, which replaced liquid electrolyte with a paste, made portable electrical devices practical.

An electrochemical cell is a device used for generating an electromotive force (voltage) and current from chemical reactions. The current is caused by the reactions releasing and accepting electrons at the different ends of a conductor. A common example of an electrochemical cell is a standard 1.5-volt battery. Batteries are composed of usually multiple Galvanic cells.

There are many general types of electrochemical cells, including galvanic cells, electrolytic cells, fuel cells, flow cells and voltaic piles. A battery's characteristics may vary due to many factors including internal chemistry, current drain and temperature.

Batteries are classified into two broad categories, each type with advantages and disadvantages.

• Primary batteries irreversibly (within limits of practicality) transform chemical energy to electrical energy. When the initial supply of reactants is exhausted, energy cannot be readily restored to the battery by electrical means.
• Secondary batteries can be recharged; that is, they can have their chemical reactions reversed by supplying electrical energy to the cell, restoring their original composition.

A battery explosion is caused by the misuse or malfunction of a battery, such as attempting to recharge a primary (non-rechargeable) battery, or short circuiting a battery. With car batteries, explosions are most likely to occur when a short circuit generates very large currents. In addition, car batteries liberate hydrogen when they are overcharged (because of electrolysis of the water in the electrolyte). Normally the amount of overcharging is very small, as is the amount of explosive gas developed, and the gas dissipates quickly. However, when "jumping" a car battery, the high current can cause the rapid release of large volumes of hydrogen, which can be ignited by a nearby spark (for example, when removing the jumper cables).

For More Information: Battery and Cell - K-12 Experiments & Background Information

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