THE DESIGN OF AIR-HOLES IN BUTTON TYPE OF ZINC-AIR BATTERIES - II - SIMULATION OF GAS-FLOWS BY AIR-HOLES

We have introduced a new concept of gas permeability of air holes, so that we can obtain suitable design guide of air holes in zinc-air batt eries. In addition to that, we simulated gas Bow through based on hydr odynamics and conducted several experiments. We compared two experimen tal results and concluded as follows. (1) Gas permeability is not prop ortional to the area of air holes but is proportional to the total cir cumferential length of air holes. For the same area of air holes, perm eabilities of both oxygen and water vapor are higher with increased nu mber of air holes with large area. hen over two air holes exist, distr ibution of oxygen concentration at the electrode surface becomes unifo rm. (2) When the ration of circumferential length vs. hole diameter is below 0.2, no significant difference was observed between permeabilit ies of oxygen and water vapor. These conclusion were found to be usefu l as guideline of the design air holes.