A redox reaction is the force behind an electrochemical cell like the Galvanic cell pictured. The battery is made out of a zinc electrode in a solution connected with a wire and a porous disk to a copper electrode in a solution.
Electrochemistry - "In this video Paul Andersen explains how electrochemical reactions can separate the reduction and oxidation portions of a redox reactions to generate (or consume) electricity. The half reactions can be analyzed to determine the potential of either a galvanic (voltaic) or an electrolytic cell. The reduction takes place at the cathode and the oxidation takes place at the anode."