| 摘要 |
PURPOSE:To restrain the falling of capacity when a large current is discharged and prevent the malfunction of internal short at the time winding by specifying the average outer dia. per piece of metal grids constituting a felt metal porous structure and the average gap between adjacent metal grids. CONSTITUTION:It is made up with a metal can 1, an electrode group 2 in which a nickel positive electrode 3 and a cadmium negative electrode 4 are wound via a separator 5, a metal sealing plate 6 and a positive electrode terminal 7. In this case, the average outer dia. per piece of metal grids constituting a felt metal porous structure of the nickel positive electrode 3 is in a range of 30-70microns and the average gap between adjacent metal grids is in a range of 100-400microns. That is, in order to prevent the penetration of the separator by the metal grids, the outer dia. of the metal grid is desirable to be as large as possible, but if this value is too large the effective cavity factor is decreased and so it is reasonably in a range of 30-70microns in practical use. Also, the average gap between adjacent metal grids is desirable to be small, but if it is too small the effective cavity factor is decreased. It is thus possible to restrain the falling of capacity when a large current is discharged and prevent the malfunction of internal short when winding. |
