A battery has a wrapper member comprising the combination of an inner layer which is pervious to gases generated by the cell and an outer layer which is impervious to liquids and which is less pervious than the inner layer to the gases generated by the cell. The inner and outer layers are laminated to one another throughout some but not all of their coextensive surfaces, with the unlaminated portions providing a passageway between the two layers for the venting of gases generated on the interior of the battery; the passageway communicates with the exterior of the battery. Preferably the inner and outer layers have coextensive surfaces which cover the entire area enclosed by the peripheral seal of the battery, and the inner layer extends into the area of and forms a component of the peripheral seal; in that case the gas passageway may extend to the area above the seal. Preferably the inner layer is an electrically conductive plastic and the outer layer is a metal.
Cells or multicell batteries are provided with vents comprising fiber-filled plastic tubes. The plastic tube walls are formed of a hydrogen-permeable, liquid-impermeable, plastic material and the fibers which fill the interior of the tube serve to maintain an open gas diffusion passage through the tube. The vents extend through seals between battery components into electrochemically active regions of the battery, into gas permeable regions of the battery outside of the electrochemically active regions, or both. The fiber filled tube can terminate in the cell interior when the end positioned within the cell is sealed with a hydrogen-permeable, liquid-impermeable, plastic layer, or the tube can extend across the battery length or width. At least one end of the tube is open to the atmosphere.
A vent system for exhausting gas generated within a battery case is provided. The vent system exhausts gas from the battery case while maintaining the hermetic seal of the case. The vent system provides a small gas exit hole that is sufficiently small to prevent electrolyte leakage and also intake of excess carbon dioxide or excess water vapor from the atmosphere. Also, various combinations of gas-permeable, hydrophobic membranes and diffuser material may cover the gas exit hole to provide humidity control for the battery while exhausting gases from the battery. A recess may be provided within the case such that the gas exit hole communicates between the atmosphere and the recess. Also, various combinations of gas-permeable, hydrophobic membranes and diffuser material may cover the recess and gas exit hole to provide humidity control for the battery while exhausting gases from the battery case. The present invention also provides a vent system in which gas-permeable, hydrophobic membranes and diffuser material may fill an opening so as to exhaust gas from the case. The present invention also provides an electrode lead which extends along the battery case and through the seam of the battery case in a manner in which a hermetic seal is provided around the lead. The manufacturing process for the seal around the lead is relatively simple.
A battery assembly and method for making the same comprising: a laminar battery, said laminar battery including: an anode layer; an ionically conductive electrolyte layer; a cathode layer; said electrolyte layer being interposed between said anode layer and said cathode layer, and said layers being assembled to form an electrical cell; a pair of electrically conductive terminals in electrical contact with said anode layer and said cathode layer; and a protective sheet material enveloping said laminar battery; said sheet material being heat sealed at the periphery of said laminar battery and about said terminals to exclude air and moisture and said terminals extending from or being accessible through said protective sheet material for connection to a device which is powered by said laminar battery is disclosed. The battery assembly is formed, and the method includes that the sealing occur under a vacuum.
A permeable membrane comprising a gas permeable substrate film and a layer of a polymeric perfluoro compound on the substrate exhibits selective transport of oxygen over water vapor and a metal-air electrochemical cell comprising such a membrane has enhanced control over its water content. Suitable polymeric perfluoro compounds include perfluoropolyalkylene oxides such as polyperfluoropropylene oxide or polyperfluoropropylene oxide co-perfluoroformaldehyde. The polymeric perfluoro compound layer is desirably crosslinked to form a thin layer on the substrate film or to form a self-supporting membrane. A suitable substrate film is a microporous polymer membrane.
A metal-air cell with an anode container. The anode container is made from a reactive metal. The metal-air cell also has an absorbent layer with a first side and a second side. An electrolyte is substantially trapped within the absorbent layer. The first side of the absorbent layer is positioned in contact with the anode container and an air electrode is positioned in contact with the second side of the absorbent layer.
