摘要 |
This invention pertains to metal-air electrochemical cells wherein one or more air entry ports is located in the bottom of the cathode can, to provide for entry of oxygen-rich air into the cathode can, where the oxygen participates in the chemical reaction whereby the cell produces electrical energy. In this invention, multiple small air entry ports are provided. Generally, the use of multiple ports distributed over the bottom of the cathode can, opposite the reaction surface of the cathode assembly, while not increasing the overall open area of the ports, results in an increase in the ratio of the cell limiting current to the rate at which moisture is lost from the cell. Accordingly, moisture loss as a function of electrical energy produced, is reduced. Preferred embodiments of the air entry ports have a stepped cross-sectional opening that provides a larger diffusion area controlling diffusion of air into and out of the cell through a covering tab prior to the cell being put into use, and a smaller untabbed diffusion area controlling diffusion of air into and out of the cell when the cell is in use.
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