Fundamental Aspects of a Rechargeable Battery

A battery consists of one or more voltaic cells. Each voltaic cell consists of two halfcells. Negatively charged anions migrate to the anode electrode (negative electrode) in one half-cell, while the positively charged cations migrate to the cathode (positive electrode) in the other halficell. The electrodes are separated by an electrolyte medium, which is ionized to create the anions and cations and to permit the movement of those ions. 

The OCV of a charged battery is the electromotive force (EMF) of a cell, which comes from the difference between the reduction potentials of the reactions in the half-cells. During the discharge phase, the battery converts the heat energy that would be released during the chemical reaction between the cathode and anode terminals. This heat energy is converted into electrical energy. 

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