iPhoneOgraphy – 22 Apr 2016 (Day 113/366)
Batteries provided the main source of electricity before the development of electric generators and electrical grids around the end of the 19th century. Successive improvements in battery technology facilitated major electrical advances, from early scientific studies to the rise of telegraphs and telephones, and eventually leading to portable computers, mobile phones, electric cars, and many other electrical devices.
Scientists and engineers developed several commercially important types of battery. “Wet cells” were open containers that held liquid electrolyte and metallic electrodes. When the electrodes were completely consumed, the wet cell was renewed by replacing the electrodes and electrolyte. Open containers are unsuitable for mobile or portable use. Early electric cars used semi-sealed wet cells.
“Primary” batteries could produce current as soon as assembled, but once the active elements were consumed, they could not be electrically recharged. The development of the lead-acid battery and subsequent “secondary” or “rechargeable” types allowed energy to be restored to the cell, extending the life of permanently assembled cells.
In 1749 Benjamin Franklin, the U.S. Polymath and founding father, first used the term “battery” to describe a set of linked capacitors he used for his experiments with electricity. These capacitors were panels of glass coated with metal on each surface. These capacitors were charged with a static generator and discharged by touching metal to their electrode. Linking them together in a “battery” gave a stronger discharge. Originally having the generic meaning of “a group of two or more similar objects functioning together”, as in an artillery battery, the term came to be used for voltaic piles and similar devices in which many electrochemical cells were connected together in the manner of Franklin’s capacitors. Today even a single electrochemical cell, e.g. a dry cell, is commonly called a battery.