| abstract |
A thermocell includes a negative electrode, such as a lead-acid electrode, and a porous oxygen (air) electrode disposed in a housing and separated by a separator. During discharge, oxygen is allowed to permeate through the oxygen electrode and separator to reach the negative electrode. Chemical oxidation of the negative electrode by oxygen in the presence of sulfuric acid yields water, lead sulfate, and heat. The heat can be used in many ways, such as warming up an adjoining automotive battery in winter, or as a personal heating pad. The heating rate is controlled by the rate of oxygen ingress. When not in use, the oxygen electrode is sealed by taping or by other means to stop ingress of oxygen. The used thermocell can be recharged by charging the negative electrode while evolving oxygen at the oxygen electrode. |