Regardless of the type, a battery is essentially a portable device that converts chemical energy to electrical energy that can be stored and used later, when needed.
Batteries are classified as either primary or secondary.
Primary batteries, like the ones you in your remote control or other electronic devices, can be used until all the energy is used (i.e., fully discharged), and then they’re usually discarded. Their chemical reactions are not reversible, so they can’t be recharged.
On the other hand, the chemistry of secondary batteries can be reversed by applying an electrical current to the cell to stimulate and regenerate the original chemical reactants – so they’re rechargeable.
Solar batteries of lithium ion chemistry – like RedEarth’s Troppo, which is lithium iron phosphate – are secondary batteries: rechargeable, long-life batteries providing high energy density and low self-discharge. They’re designed for use with photovoltaic (solar) panels to meet the sustained energy needs of a building over a longer period. Lightweight and efficient, those using lithium ferro phosphate (LFP) chemistry will typically last at least a decade, or longer.
While batteries used in internal combustion engine vehicles are also classified as rechargeable, they differ from solar batteries in chemistry, function, and purpose. Traditional car batteries, for example, are typically lead-acid and are designed to generate a quick burst of electricity to start an engine. They have moderate energy density, a moderate rate of self-discharge and typically last for five to six years.
Early batteries consisted of an earthenware container filled with sulfuric acid and a zinc electrode, which was then immersed in a copper pot containing copper sulphate. We’ve come a long way from there!