Invention Of Battery | Details of Battery

Invention Of Battery

One fateful day in 1780, Italian physicist, physician, biologist, and philosopher, Luigi Galvani, was dissecting a frog attached to a brass hook. As he touched the frog's leg with an iron scapel, the leg twitched. Galvani theorized that the energy came from the leg itself, but his fellow scientist, Alessandro Volta, believed otherwise.

Volta hypothesized that the frog's leg impulses were actually caused by different metals soaked in a liquid. He repeated the experiment using cloth soaked in brine instead of a frog corpse, which resulted in a similar voltage. Volta published his findings in 1791 and later created the first battery, the voltaic pile, in 1800.

 The voltaic pile consisted of a stack of zinc and copper plates separated by cloth soaked in brine

Volta's pile was plagued by two major issues: the weight of the stack caused the electrolyte to leak out of the cloth, and the particular chemical properties of the components resulted in a very short life span (about an hour). The next two hundred years would be spent perfecting Volta's design and solving these issues.

Fixes to the voltaic Pile:

William Cruickshank of Scotland solved the leakage problem by laying the voltaic pile on its side to form the "trough battery."

The trough battery solved the leakage problem of the voltaic pile

The second problem, short life span, was caused by the degradation of the zinc due to impurities and a build up of hydrogen bubbles on the copper. In 1835, William Sturgeon discovered that treating the zinc with mercury would prevent degradation.

The British chemist John Frederic Daniell used a second electrolyte that reacted with the hydrogen, preventing buildup on the copper cathode. Daniell's two-electrolyte battery, known as the "Daniell cell," would become a very popular solution to providing power to the budding telegraph networks.

The First Rechargeable Battery

In 1859, the French physicist Gaston Planté created a battery using two rolled sheets of lead submerged in sulfuric acid. By reversing the electrical current through the battery, the chemistry would return to its original state, thus creating the first rechargeable battery.

Later, in 1881, Camille Alphonse Faure improved Planté's design by forming the lead sheets into plates. This new design made the batteries easier to manufacture, and the lead acid battery saw wide-spread use in automobiles.

The Dry Cell

Up until the late 1800s, the electrolyte in batteries was in a liquid state. This made battery transportation a very careful endeavor, and most batteries were never intended to be moved once attached to the circuit.

In 1866, Georges Leclanché created a battery using a zinc anode, a manganese dioxide cathode, and an ammonium chloride solution for the electrolyte. While the electrolyte in the Leclanché cell was still a liquid, the battery's chemistry proved to be an important step for the invention of the dry cell.

Carl Gassner figured out how to create an electrolyte paste out of ammonium chloride and Plaster of Paris. He patented the new "dry cell" battery in 1886 in Germany.

These new dry cells, commonly called "zinc-carbon batteries," were massed produced and proved hugely popular until the late 1950s. While carbon is not used in the chemical reaction, it performs an important role as an electrical conductor in the zinc-carbon battery.

 3V zinc-carbon battery from the 1960s
(Image courtesy of PhFabre of Wikimedia Commons) 

In the 1950s, Lewis Urry, Paul Marsal, and Karl Kordesch of the Union Carbide company (later known as "Eveready" and then "Energizer") replaced the ammonium chloride electrolyte with an alkaline substance, based on the battery chemistry formulated by Waldemar Jungner in 1899. Alkaline dry cell batteries could hold more energy than zinc carbon batteries of the same size and had a longer shelf life.

Alkaline batteries rose in popularity in the 1960s, overtook zinc-carbon batteries, and have since become the standard primary cell for consumer use.

Recent Rechargeable Battery

In the 1970s, COMSAT developed the nickel-hydrogen battery for use in communication satellites. These batteries store hydrogen in a pressurized, gaseous form. Many man-made satellites, like the International Space Station, still rely on nickel-hydrogen batteries.

The research of several companies since the late 1960s resulted in the createion of the nickel-metal hydride (NiMH) battery. NiMH batteries were released to the consumer market in 1989, and provided a smaller, cheaper alternative to the rechargeable nickel-hydrogen cells.

Asahi Chemical of Japan built the first lithium-ion battery in 1985, and Sony created the first commercial lithium-ion battery in 1991. In the late 1990s, a soft, flexible casing was created for lithium-ion batteries and gave rise to the "lithium polymer" or "LiPo" battery.

Operation

Batteries generally require several chemical reactions in order to operate. At least one reaction occurs in or around the anode and one or more reactions occur in or around the cathode. In all cases, the reaction at the anode produces extra electrons in a process called oxidation, and the reaction at the cathode uses the extra electrons during a process known as reduction. When the switch is closed, the circuit is complete, and electrons can flow from the anode to the cathode.These electrons enable the chemical reations at the anode and cathode.

In essence, we are separating a certain kind of chemical reaction, a reduction-oxidation reaction or redox reaction, into two separate parts. Redox reactions occur when electrons are transferred between chemicals. We can harness the movement of electrons in this reaction to flow outside the battery to power our circuit.

 Dead Battery

The chemicals in the battery will ultimately reach a state of equilibrium. In this state, the chemicals will no longer have a tendency to react, and as a result, the battery will not generate any more electric current. At this point, the battery is considered "dead."

Primary cells must be disposed when the battery is dead. Secondary cells can be recharged, and this is accomplished by applying a reverse electric current through the battery. Recharging occurs when the chemicals perform another series of reactions to take them back to their original state.

Capacity

Many batteries, especially powerful lithium-ion batteries, express discharge current as "C-Rate" in order to more clearly define battery attributes. C-Rate is the rate of discharge relative to the battery's maximum capacity.

1C is the amount of current required to discharge the battery in 1 hour. For example, a 400 mAh battery supplying 1C of current would be supplying 400 mA. 5C for the same battery would be 2 A.

Most batteries lose capacity at higher current draws. For example, this product info graph from Charger shows that their LiPo cell has less mAh at higher C-Rates.

C-Rate

Many batteries, especially powerful lithium-ion batteries, express discharge current as "C-Rate" in order to more clearly define battery attributes. C-Rate is the rate of discharge relative to the battery's maximum capacity.

1C is the amount of current required to discharge the battery in 1 hour. For example, a 400 mAh battery supplying 1C of current would be supplying 400 mA. 5C for the same battery would be 2 A.

Most batteries lose capacity at higher current draws. For example, this product info graph from Charger shows that their LiPo cell has less mAh at higher C-Rates.