Installation Design for Valve-Regulated Sealed Lead-Acid Batteries in Generating Stations
Commercially available large-capacity valve-regulated sealed lead-acid batteries represent a novel technology for large stationary batteries for emergency power applications, using an oxygen recombinant cycle to inhibit the generation of hydrogen under normal operation. A discussion is presented of the installation design for these batteries, making comparisons to traditional vented lead-acid cells as appropriate. The operation of the valve-regulated sealed lead-acid battery is also described. >
Maintaining 'maintenance-free' batteries
The maintenance of valve-regulated sealed lead-acid stationary batteries is described, and comparisons are made with traditional vented lead-acid battery maintenance practices. The operation of the valve-regulated sealed lead-acid battery is also discussed. Two designs are currently available, both of which operate on the oxygen recombinant cycle. This cycle effectively eliminates evolution of free hydrogen gas under normal operating conditions. Maintenance considerations for valve-regulated sealed lead-acid cells are similar to those for flooded cells. It is noted that the terms 'sealed' and 'maintenance-free' commonly associated with these cells are misnomers, and it is urged that the use of such terms should be discontinued.<<ETX>>
The charging of large lead-acid batteries with gelled electrolyte
Charge voltage limits recommended for recharging lead-acid batteries with gelled electrolyte are as low as 2.32-2.35V/cell. Gelled-acid batteries will retain capacity over many cycles when recharged to these voltages. In contrast, similar lead-acid batteries with liquid electrolyte require voltage limits of 2.5 to 2.67 to maintain capacity. The main factor which permits the recharging of gelled-acid batteries at such low voltages is the depolarization of the negative electrode by the oxygen recombination reaction. The gelled acid may also play a role in facilitating the conversion of lead sulfate to lead dioxide. The lower voltages required for the gelled batteries result in less water loss and lower operating temperatures.