| 摘要 |
This invention teaches rechargeable manganese dioxide cells having alkaline electrolytes, zinc negative electrodes and manganese dioxide positive electrodes. In keeping with the present invention, the positive electrode is essentially unconstrained-that is, no cage is used in the cell to confine the positive electrode. During discharge of a rechargeable alkaline cell, the positive electrode may be inclined to swell, and during the charge cycle it may be inclined to contract or reduce its dimensions. However, the positive electrode is dimensioned so as to substantially fill the entire space allotted for it within the cell, while allowing for a slight accommodation for height-wise or longitudinal expansion or growth in bobbin cells. The positive electrode may include additives such as carbon or graphite to increase its electrical conductivity; hydrophobic agents such as PTFE, polyethylene or polypropylene to enhance the hydrogen permeability of the positive electrode and thereby lead to increased hydrogen recombination rates; and similar hydrophobic agents as well as hydrophillic additives to serve as lubricants and to reduce tool wear during manufacturing processes. Also, the discharge capacity of the negative electrode may be established so as to be in the range of from about 60% to about 120% of the theoretical one electron discharge capacity of the positive MnO2 electrode. |
