Abstract: An improved electrolyte circulation subsystem which reduces and minimizes the effect of parasitic currents in secondary batteries having a plurality of cells connected electrically in series and a common electrolyte in communication with the cells is described. The improved electrolyte circulation subsystem includes means for pumping an electrolyte, and manifold means for conveying electrolyte to a plurality of cells connected electrically in series. The manifold means generally comprises an outer tube formed with an outlet port at each end thereof, and an inner tube concentrically disposed within the outer tube generally along one-half of the outer tube length. The inner tube is in fluid communication with the pumping means at a first end thereof and is in fluid communication with the outer tube at a second end thereof. The inner tube also has means associated with the second end for generally equally diverting the flow of the electrolyte through the inner tube to each of the outlet ports of the outer tube.

Abstract: A self-draining decomposition heat exchanger arrangement for a metal-halogen battery system is disclosed. The arrangement has a decomposition heat exchanger positioned higher than the electrolyte collected in the sump of the electrode stack section of the battery system to allow electrolyte to drain out of the heat exchanger when electrolyte is not being circulated therethrough. The heat exchanger has an inlet portion, an outlet portion, and a central portion that is preferably formed of helically coiled tubing and that preferably slopes continuously downward to promote complete drainage. The arrangement preferably also has vent means connected to the gas space above the sump in the stack section and attached to conduit means between the outlet of the electrolyte pump and inlet of the heat exchanger for improving drainage of the heat exchanger by allowing gas to enter the heat exchanger to replace the electrolyte as it drains therefrom.