There are wonders of the 21st century that have become so commonplace that we take them for granted, even if they remain out of sight. Batteries are only one example. yet if we pause and think about it the development of batteries is a fascinating story – the potential future uses of battery technology are perhaps even more exciting. Batteries function as small reservoirs of energy. They allow chemical energy to be converted into electrical energy that can power devices of all types.
Although batteries may seem like an invention that is fairly recent, given how important they are to modern life, they have in fact been around for centuries. In fact, the Director of the Baghdad discovered what may very well be one of the first examples of the battery – oner that was in use around 250BC. The so-called ‘Baghdad Battery’ is thought to have had its origins in Mesopotamia. Just how the battery was used is still up for debate – but possible sues include electroplating, treatment of chronic pain or use in religious ceremonies.
The term ‘battery’ was penned by prodigious inventor and American luminary Benjamin Franklin during his exploration of the properties of electricity – an area that he focused on. He first used the term in 1749 while experimenting with linked capacitors.
However, the genesis of the modern battery owes much to Italian physicist Alessandro Volta. It was he who stacked copper discs (Cu) and Zinc (Zn) which were separated by salt water-soaked cloth.
The mechanism was revolutionary. Wires were attached to either pole of the stack and this produced a stable current. Each ‘cell’ or unit of Copper and Zinc discs produced 0.76 Volts (V). Multiply that by the number of cells and you have the output of the battery assembly.
The Lead-acid battery, which is still in use today was invented in 1859. The modern variant is still essential for the functioning of modern automobiles. The original design was the first to offer the option of recharging spent cells.
Battery technology continued to evolve from its humble beginnings, Today we have batteries that range from those used in electrical substations that power entire communities to those that power pacemakers. See here for APC UPS battery.
Such has been the advancement of chemistry that there are now many different types of batteries that rely on various chemical reactions to produce power. Cell voltages usually range from around 1.0 to 3.6 Volts. Stack them up and the Voltage increases accordingly. Used in parallel and more current is generated. This is the principle that allows for the development of batteries that can supply Megawatts of power.
But what was one the humble battery seems poised to take another leap forward. Storage of output from solar and wind generation systems is one of the driving forces behind the development of new and more efficient batteries. It is anticipated that batteries will soon allow homes to be powered for extended periods – even in the absence of sunlight.
What’s the Science?
When a battery discharges stored energy a chemical reaction produces excess electrons. One example is when iron oxidizes (and rust is formed). As the iron reacts with oxygen it gives up electrons when iron oxide is formed.
Most standard batteries use two different metals (or other compounds) with varying chemical potentials. These are separated with a porous insulator. The ‘chemical potential’ is the energy stored in atoms (and the bonds between them). This is imparted to the moving electrons when they move through the external device connected to the battery.
A conducting fluid (one of the simplest is saltwater) transfers soluble ions from one metal to the other during a reaction – this is called an electrolyte.
During the process, the metal (or compound) that loses electrons is termed the ‘anode’, and the metal (or compound) that gains the electrons is called the ‘cathode.’