| 摘要 |
In order to establish the functions of a closed type lead-acid secondary battery, a sealed type secondary battery, the present invention intends to achieve a combination of keeping a state of requiring no maintenance, a so called maintenance free feature, by controlling the amount of hydrogen evolved in a small acceptable range and of improving a charge recoverability after discharging at a fine electric current or overdischarging, or after overdischarging followed by leaving to stand for a while which are often encountered with the sealed battery. The improvement of the charge recoverability after discharging followed by leaving to stand can be achieved by allowing almost all the requisite electrolyte, except a very small amount of free liquid, to be absorbed in positive and negative electrodes and absorptive separators and by providing a coating layer of a lead-antimony based alloy on a portion of or all the surfaces of network positive electrodes made of a lead-calcium based alloy. |
