Autoclavable electrochemical cell

Abstract

An autoclavable elctrochemical cell which may be used in an implantable medical device. The anode active material is lithium or other material from groups IA and IIA of the Periodic Table and having a melting point greater than about 150 degrees C. The cathode active material is silver vanadium oxide or other metal oxide or carbon monofluoride. The solvent for the electrolyte has a boiling point greater than about 100 degrees C. and a dielectric constant greater than about 5 so that the cell may be dimensionally and chemically stable during repeated exposures of about one hour each to the autoclaving temperatures.

What is claimed is:  
     
         1 . An electrochemical cell comprising: a casing; an anode having as active material a material which has a melting point greater than about 150 degrees C. and which is selected from groups IA and IIA of the Periodic Table; a cathode having as active material a material which is selected from the group of materials consisting of metal oxides, metal oxide bronzes, and carbon monofluoride; and an electrolyte comprising a lithium salt and an organic solvent, said solvent characterized by having a boiling point greater than about 100 degrees C. and a dielectric constant greater than about 5.  
     
     
         2 . A cell according to    claim 1    wherein said anode active material is lithium.  
     
     
         3 . A cell according to    claim 1    wherein said cathode active material is silver vanadium oxide.  
     
     
         4 . A cell according to    claim 1    wherein said anode active material is lithium and wherein said cathode active material is silver vanadium oxide.  
     
     
         5 . A cell according to    claim 4    wherein said solvent is a mixture of propylene carbonate and diglyme and wherein said salt is lithium trifluoromethane sulfonate.  
     
     
         6 . A cell according to    claim 4    wherein said solvent is a mixture of propylene carbonate and diglyme.  
     
     
         7 . A cell according to    claim 6    further comprising a separator means between said anode and said cathode, said separator means composed of a material which is porous for passage of said electrolyte therethrough and which is characterized by being wettable to said electrolyte and by having a melting point which is greater than about 130 degrees C.  
     
     
         8 . A cell according to    claim 7    wherein said separator material is composed of a laminate of a polypropylene membrane and a polypropylene mesh.  
     
     
         9 . A cell according to    claim 7    wherein said salt is lithium trifluoromethane sulfonate.  
     
     
         10 . A cell according to    claim 1    wherein said solvent is a mixture of propylene carbonate and diglyme and wherein said salt is lithium trifluoromethane sulfonate.  
     
     
         11 . A cell according to    claim 1    further comprising a separator means between said anode and said cathode, said separator means composed of a material which is porous for passage of said electrolyte therethrough and which is characterized by being wettable to said electrolyte and by having a melting point which is greater than about 130 degrees C.  
     
     
         12 . A cell according to    claim 1    comprising means for maintaining the cell dimensionally and chemically stable during repeated exposures each of about one hour to a temperature of about 130 to 135 degrees C.  
     
     
         13 . A cell according to    claim 1    wherein said casing is hermetically sealed and is composed of corrosion-resistant material.  
     
     
         14 . A cell according to    claim 1    wherein said cathode active material is carbon monoflouride, said cathode includes a current collector composed of a material selected from the group consisting of a superferrite material and carbon coated titanium, said salt is selected from the group consisting of lithium tetrafluoroborate and lithium trifluoromethane sulfonate, and said solvent is gammabutyrolactone.  
     
     
         15 . An autoclavable electrochemical cell comprising a casing; an anode having as active material a material which has a melting point greater than about 150 degrees C. and which is selected from groups IA and IIA of the Periodic Table; a cathode having as active material a material which is selected from the group of materials consisting of metal oxides, metal oxide bronzes, and carbon monoflouride; and an electrolyte comprising a lithium salt and an organic solvent, said solvent characterized by having a boiling point greater than about 100 degrees C. and a dielectric constant greater than about 5, the cell further characterized by being dimensionally and chemically stable during repeated exposures each of about one hour to a temperature of about 130 to 135 degrees C.  
     
     
         16 . A cell according to    claim 15    wherein said anode active material is lithium and wherein said cathode active material is silver vanadium oxide.  
     
     
         17 . A cell according to    claim 15    further comprising a separator means between said anode and said cathode, said separator means composed of a material which is porous for passage of said electrolyte therethrough and which is characterized by being wettable to said electrolyte and by having a melting point which is greater than about 130 degrees C.  
     
     
         18 . An electrochemical cell comprising: a casing; a lithium anode; a silver vanadium oxide cathode; and an electrolyte comprising lithium trifluoromethane sulfonate and an organic solvent, said solvent being a mixture of propylene carbonate and diglyme.  
     
     
         19 . A cell according to    claim 18    further comprising a separator means between said anode and said cathode, said separator means composed of a material which is porous for passage of said electrolyte therethrough and which is characterized by being wettable to said electrolyte and by having a melting point which is greater than about 130 degrees C.  
     
     
         20 . A cell according to    claim 18    comprising means for maintaining the cell dimensionally and chemically stable during repeated exposures each of about one hour to a temperature of about 130 to 135 degrees C.