The Peltier effect is the reverse of the Seebeck effect; a creation of a heat difference (between two joint) from an electric voltage. This temperature difference gives rise to a seebeck voltage which is opposite to the voltage of the cell. So we can resonably conclude that it can contribute to the loss of voltage of the battery, can't we? I understand seebeck effect but not peltier .... I dont understand why heat energy should be released when electron flow from a higher density to lower density site when it is propelled by an energy source (battery).