Electrochemical emergo storage and / or energy supply cell with pH control

摘要

An electrochemical process for energy storage and/or power generation and apparatus comprises cell array of unit cells (10), each cell comprising a +ve electrode (12) and a -ve electrode (14) with a membrane in each cell dividing it into +ve and -ve chambers (22C and 24C) for catholyte and anolyte solutions (22, 24) which are recirculated through separate pumps (26, 28) and storage tanks (32, 34) and back to the chambers. Mid electrodes, between adjacent cells in the array, provide both a +ve side and a -ve side. A bromine-sulfur couple may be employed. Means are provided to compensate for pH changes and/or changes in hydroxyl ion concentration in the +ve and/or the -ve sides of the array of cells. Means are provided to affect some limited occurrence of trans-membrane migration or other losses of bromine, sulfur and/or water and to limit the effects of bromine acidification, while affording high energy storage and high power with stable operation over long periods and to maintain output power and voltage at high levels throughout substantially all the discharge cycle.