Abstract: A battery system includes an electrical storage cell having a positive terminal and a negative terminal. The electrical storage cell is provided with a normally open bypass circuit path that is closed in the event of an open-circuit failure of the electrical storage cell. The bypass circuit path includes a first electrical conductor connected to the positive terminal of the electrical storage cell, a second electrical conductor connected to the negative terminal of the electrical storage cell, and a shorting gap between the first electrical conductor and the second electrical conductor. A mass of a fusible material is positioned at an initial mass location. A heat source is activatable upon the occurrence of an open-circuit condition of the electrical storage cell. The heat source is operable to melt at least a portion of the mass of the fusible material and thereby to close the shorting gap so that the first electrical conductor is in electrical communication with the second electrical conductor.

Abstract: A battery system includes an electrical storage cell having a positive terminal and a negative terminal. The electrical storage cell is provided with a normally open bypass circuit path that is closed in the event of an open-circuit failure of the electrical storage cell. The bypass circuit path includes a first electrical conductor connected to the positive terminal of the electrical storage cell, a second electrical conductor connected to the negative terminal of the electrical storage cell, and a shorting gap between the first electrical conductor and the second electrical conductor. A mass of a fusible material is positioned at an initial mass location. A spring is positioned to force the mass of the fusible material from the initial mass location, along the metal flow path, and into the shorting gap, when the mass of the fusible material is at least partially molten. A heat source is activatable upon the occurrence of an open-circuit condition of the electrical storage cell.

Abstract: A pressurized-gas battery, such as a nickel-hydrogen battery, is rapidly charged at a high charging rate until the measured pressure reaches a high-pressure limit, and thereafter slowly charged at a reduced charging rate as the measured pressure falls toward a low-pressure limit. The high-pressure limit and the low-pressure limit each decrease with increasing temperature.

Abstract: An energy storage cell includes a vessel having a wall with a pair of oppositely disposed apertures therethrough, and an electrochemical cell, such as a nickel-hydrogen cell, within the vessel interior. A central core extends through the oppositely disposed apertures and performs all basic electrical, compressive support, and thermal removal functions for the energy storage cell. The central core includes electrical interconnects for the plate sets of the electrochemical cell, axial compression loading supports for the plate sets, and a heat pipe or other structure for removing heat from the interior of the vessel.

Abstract: A battery system includes an electrical storage cell having a positive terminal and a negative terminal. The electrical storage cell is provided with a normally open bypass circuit path that is closed in the event of an open-circuit failure of the electrical storage cell. The bypass circuit path includes a normally open bypass circuit path comprising a diode having a cathode and an anode. The cathode of the diode is electrically connected to the positive terminal of the electrical storage cell and the anode of the diode is electrically connected to the negative terminal of the electrical storage cell. The diode fails to a shorted current path at an imposed current less than a cell failure current, providing a low-resistance, low-voltage-drop bypass of the electrical storage cell.

Abstract: A battery cell terminal having structure for receiving a thermal conductor. The receiving structure may comprise a bore defined by an inner surface of the terminal. The thermal conductor may be a heat pipe or other suitable conductor. A layer of electrical insulation may be disposed between the terminal and the thermal conductor. The terminal conducts heat produced by electrodes in the cell to the thermal conductor which then conducts the heat to a heat sink.

Abstract: An apparatus and method for controlling the temperature of a battery used in a spacecraft or an electric vehicle are disclosed. The apparatus includes a thermal conductor, such as a thermally-conductive heat pipe or forced-fluid cooling loop, that is in thermal contact with thermally-conductive cell terminals of the battery, and a heat sink, such as a radiator. The inventive method includes operating the battery to generate and conduct heat to the thermally-conductive battery cell terminals. The generated heat is passed via conduction from the terminals to the thermal conductor. The heat is conducted through the thermal conductor to a heat sink which may be remotely located with respect to the battery. Preferably, the thermal conductor remains electrically insulated from the battery cell terminals and the heat sink.

Abstract: A nickel-hydrogen energy storage cell includes a hermetic pressure vessel having a wall made of a nickel-base alloy, and a hollow tube made at least in part of palladium and joined to the wall of the pressure vessel such that an interior of the hollow tube is in communication with an interior of the pressure vessel. A heater controllably heats at least a portion of the hollow tube to increase the diffusion rate of hydrogen through the wall of the hollow tube and thereby controllably vent hydrogen from the pressure vessel. The energy storage cell further includes at least one plate set within the wall of the pressure vessel, an electrolyte, and a pair of electrical leads extending from the at least one plate set and through an electrical feedthrough in the wall of the pressure vessel.

Abstract: A battery system includes a battery cell having a cylindrical battery cell housing and a housing support external to the battery cell housing. The housing support is formed of an electrical insulator layer contacting the cylindrical external surface of the battery cell housing, and a heat conductor formed of heat-conducting fibers overlying and contacting the electrical insulator layer and aligned generally parallel to the cylindrical axis of the battery cell housing. The heat-conducting fibers are made of high-thermal-conductivity graphite and have a sink end. A fiber-reinforced composite structural support layer is applied overlying the heat-conducting fibers to force the electrical insulator layer into contact with the battery cell housing without the presence of an adhesive between the electrical insulator and the battery cell housing. A thermal sink is in thermal contact with the sink ends of the plurality of heat-conducting fibers at a first end of the cylindrical battery cell housing.

Abstract: A group of electrically interconnected energy storage cells, such as nickel-hydrogen energy storage cells, is pressure balanced and its precharge reset by discharging the energy storage cells of the group to a substantially fully discharged state, venting all of the energy storage cells of the group to the same reduced internal hydrogen pressure, and thereafter discontinuing the venting. The venting occurs without recharging the energy storage cells, and after venting is complete the energy storage cells of the group are recharged.

Abstract: A battery reconditioning system and method for a spacecraft which utilizes a single battery as a secondary source of power for spacecraft electrical loads (10). The battery (14) includes a plurality of serially connected packs (30-36) each including a plurality of cells (40-46) connected in series. Sensors (50-56) are provided with each pack for sensing the state of charge of the pack. Battery charging circuitry (12,18,20) is controlled from control circuitry (22,52) which is responsive to the state of charge sensors as well as commands from a ground station transceiver (57). Reconditioning resistors (60-66) are adapted to be connected across the individual packs through switches (70-76) which are controlled by the control circuitry to discharge the pack at a relatively high rate when reconditioning is desired. After a pack is discharged to a desired low state of charge, its reconditioning resistor is disconnected and all packs are recharged in series.

Abstract: A battery (20) includes a battery container (22), a base (30) attached to the interior of the wall (24) of the battery container (22), a compliant first weld ring (32) extending to a first side of the base (30), and a compliant second weld ring (34) extending to a second side of the base (30). A first electrochemical storage cell stack (36) is supported on a core (42) extending from the first weld ring (32), and a second electrochemical storage cell stack (38) is supported on a separate core (42) extending from the second weld ring (34). Each of the storage cell stacks (36,38) includes a set of storage cells (40) and a gas screen (68) between each of the storage cells (40). The gas screens (68) are dimensioned to extend outwardly to contact the wall (24) of the battery container (22), thereby serving to damp vibrations in the storage cell stack (36, 38 ).

Abstract: A battery system comprises a plurality of sodium-sulfur storage cells connected in series to form a battery, with voltage measurement leads attached across each of the individual storage cells. A charge-limiting circuit controllably isolates an individual storage cell from a charging current applied across the battery when the measured voltage across that individual storage cell exceeds a preselected maximum storage cell voltage. Preferably, the charge-limiting circuit includes a bypass circuit connected through the voltage measurement leads and a circuit element that becomes conductive when the voltage across the individual storage cell exceeds the preselected maximum storage cell voltage. There are a plurality of charge-limiting circuits, one for each of the storage cells of the battery.

Abstract: Improved nickel-hydrogen batteries (10) are disclosed, wherein the improvement provides for wettable porous polypropylene cloth gas diffusion screens (12) to separate the individual cells (16) thereof. When necessary, substantially all of the electrolyte may be readily drained from the cells (16) of the batteries (10). Wettability is achieved by oxidizing the surfaces of the cloth gas diffusion screens (12) prior to assembling them in the batteries (10).

Abstract: A deformable element is placed between the active plate sets of a storage battery to accommodate, by permanent compressive deformation, the swelling that occurs in the positive electrode of the plate set during extended cycling of the storage battery. The plate sets are normally supported on a core under axial compressive loading, and the swelling would otherwise deform or place a strain on the electrode connector leads, which could cause them to fail by shorting. The deformable element, preferably a modified polypropylene screen that permits the release of gas from the electrode and also is deformable in the direction perpendicular to the screen, compressively deforms to absorb the gradually increasing swelling of the positive electrode. The loading on the electrode connectors is thereby avoided or minimized, removing a major potential cause of failure.

Abstract: The conventional sintered, thin hydrogen negative electrode of a nickel-hydrogen storage cell or the like is replaced by a thicker porous electrode having a greater volume to receive water produced at the negative electrode during discharge of the cell. As a result, the dilution of the electrolyte within the negative electrode is less as compared with the thinner electrode, so that the freezing point depression of the electrolyte within the negative electrode is maintained. Freezing of the electrolyte and reduced performance of the cell are thereby avoided. To maintain the low weight of the electrode and reduce its cost even though its thickness is increased, platinum particles are replaced by conductive particles upon which platinum has been deposited.

Abstract: A sodium sulfur electrical storage cell includes means for avoiding bubbles in the sulfur cathode during operation in a weightless environment. Formation of bubbles of sulfur or other gas in the cathode is prevented by pressurizing the sulfur cathode to a pressure greater than the vapor pressure of the sulfur at the operating temperature, typically about 350 C. The applied pressure is preferably supplied by a chemical compound, such as sodium azide, that is placed into the chamber holding the sulfur. At the operating temperature of the cell, the compound decomposes to produce a gas, nitrogen in the case of the sodium azide, that is substantially insoluble in the sulfur yet produces a sufficiently high pressure over the liquid sulfur that bubbles of gaseous sulfur or other gases cannot form in the sulfur. If bubbles were permitted to form in a weightless environment, they would migrate to a location where they would interfere with the operation of the cell.

Abstract: A process and apparatus for controlling the charging of pressurized gas-metal cells such as nickel-hydrogen cells, to prevent detrimental overcharging, wherein the time rate of change of a battery gas pressure index is monitored as a control parameter. When the time rate of change of the index falls below a preselected value, charging is discontinued. The cell gas pressure index can be gas pressure itself, or a quantity which is responsive to, and depends upon gas pressure, such as the deformation of a cell component.

Abstract: A process for preventing electrical capacity loss during storage of a pressurized nickel-hydrogen electrical storage cell. An electrical precharge is applied to the positive electrode of the cell, so that discharge of the cell is negative electrode limited. In one approach, the cell is charged, while sealed, to a state of charge corresponding to a first gas pressure, and then the hydrogen pressure is reduced to a lower value, preferably about atmospheric. In another approach, a current is passed through the cell while the cell is unsealed and maintained at atmospheric gas pressure, until the cell reaches the desired state of charge.

Abstract: A process is provided for removing contaminating residues left behind during fabrication of gas electrodes employed in metal/gas batteries, e.g., nickel/hydrogen batteries, and fuel cells employing gas electrodes. Such residues arise from depositing and sintering on a conductive, screen-type electrode substrate a platinum powder/polytetrafluoroethylene powder mixture containing a suspending agent. The residues of the suspending agent are removed by contacting the fabricated electrode with a solvent mixture comprising a first solvent, e.g., trichloroethylene, for dissolving the residues and a second solvent, e.g., ethanol, for wetting the polytetrafluoroethylene.