Most aircraft require some form of electrical power to operate navigation-, taxi-, landing-, strobe lights, one or more COM and NAV radio's, transponder, intercom and other advanced electronic system of your choice. The electrical system consist of a battery and an alternator or generator on older aircraft. All of this is connected through several meters (kilometers/ miles in large aircraft) of wire.
All matter on Earth is made up from molecules and they basically consist of atoms. These atoms are made of electrons, protons and neutrons. And electricity is about the flow of free electrons attracted to protons and repelled by other electrons.
Batteries work on molecular diffusion through an electrolyte. The force that drives diffusion is an internal electrical potential at the electrodes known as an over-potential. It raises the voltage needed to charge batteries, and decreases the voltage available externally upon discharge. This effect results in heat during charge and discharge. And as more power is required from or to the battery more heat is generated, degrading the lifespan even more.
A very interesting presentation about battery fundamentals from the Battery University which explains clearly some important physics of these energy storage devices.
The presentation below introduces the reader into the basics of energy storage batteries. It is written by Isidor Buchmann founder and CEO of the Battery University.
To continue reading see the pdf below: