High rate batteries

Abstract

Improved high rate batteries based on silver vanadium oxide yield improved pulsed performance. In particular, batteries comprise an electrolyte having lithium ions and a cathode comprising silver vanadium oxide. Improved batteries have a pulsed specific energy of at least about 575 mWh/g when pulsed in groups of four-10 second pulses at a current density of 25 mA/cm 2 spaced by 15 seconds between pulses and with 30 minutes between pulse groups down to a discharge voltage of 1.5 volts. In addition, improved batteries can achieve high maximum specific powers, high current densities and no voltage delay in pulsed operation. The batteries are particularly suitable for use in implantable medical devices, such as, defibrillators, pacemakers or combinations thereof. Improved processing approaches are described.

What is claimed is:  
     
         1 . A battery comprising an electrolyte comprising lithium ions and a cathode comprising silver vanadium oxide particles, the battery exhibiting no significant voltage delay near 2.6 volts.  
     
     
         2 . The battery of  claim 1  wherein the electrical resistance does not increase substantially upon discharge to 1.5 volts.  
     
     
         3 . The battery of  claim 1  wherein the cathode comprises at least about 10 weight percent electrically conductive, electro-chemically inert particles.  
     
     
         4 . The battery of  claim 1  wherein the silver vanadium oxide particles have an average diameter less than about 1000 nm.  
     
     
         5 . The method of  claim 1  wherein the silver vanadium oxide particles have an average diameter less than about 500 nm.  
     
     
         6 . The battery of  claim 1  wherein silver vanadium oxide particles comprise Ag x V 2 O y , with 0.3≦x≦2.0 and 4.5≦y≦6.0.  
     
     
         7 . The battery of  claim 1  having a pulse specific energy of at least about 600 mWh/g.  
     
     
         8 . The battery of  claim 1  having a pulse specific capacity of at least about 275 mAh/g to 1.5 volts.  
     
     
         9 . The battery of  claim 1  having a maximum pulse specific power of at least about 1.5W/g to 1.5 volts.  
     
     
         10 . The battery of  claim 1  wherein the anode comprises lithium metal foil.  
     
     
         11 . The battery of  claim 1  wherein the anode comprises lithium metal particles.  
     
     
         12 . The battery of  claim 1  wherein pulse trains can be supplied by the battery at current densities greater than about 50 mA/cm 2 .  
     
     
         13 . The battery of  claim 1  wherein the cathode has a thickness of at least about 0.8 mm.  
     
     
         14 . The battery of  claim 1  wherein the cathode has a density from about 1.8 g/cc to about 2.8 g/cc.  
     
     
         15 . An implantable medical device comprising a battery of  claim 1 .  
     
     
         16 . An implantable medical device of  claim 15  having defibrillating function.  
     
     
         17 . An implantable medical device of  claim 15  having defibrillating and cardiac pacing functions.  
     
     
         18 . A method for producing an electrode, the method comprising: 
 mixing with low shear in a homogenizer, a composition comprising 
 silver vanadium oxide particles, electrically conductive particles, binder and solvent; and  
   forming the mixed composition into an electrode.    
     
     
         19 . The method of  claim 18  wherein the silver vanadium oxide particles have an average diameter less than about 1000 nm.  
     
     
         20 . The method of  claim 18  wherein the electrically conductive particles comprise conductive carbon.  
     
     
         21 . The method of  claim 18  wherein the binder comprises a polymer selected from the group consisting of polyvinylidene fluoride, polyethylene oxide, polyethylene, polypropylene, polytetrafluoro ethylene, polyacrylates, ethylene-(propylene-diene monomer) copolymer (EPDM) and mixtures and copolymers thereof.  
     
     
         22 . The method of  claim 18  wherein the solvent is selected from the group consisting of propylene carbonate, dimethyl carbonate, diethyl carbonate, 2-methyl tetrahydrofuran, dioxolane, tetrahydrofuran, 1, 2-dimethoxyethane, ethylene carbonate, γ-butyrolactone, dimethyl sulfoxide, acetonitrile, formamide, dimethyl formamide, nitromethane, diglyme, triglyme, methyl ethyl carbonate and mixtures thereof.  
     
     
         23 . The method of  claim 18  wherein shear is provided by a homogenizer mixing at a rate from about 8000 rpm to about 24,000 rpm.  
     
     
         24 . The method of  claim 18  further comprising incorporating a metal current collector into the electrode.  
     
     
         25 . The method of  claim 24  wherein the current collector comprises a metal grid.  
     
     
         26 . A method for forming a battery, the method comprising producing a cathode according to the method of  claim 18 .  
     
     
         27 . The method of  claim 26  wherein the battery comprises an anode comprising elemental lithium metal.  
     
     
         28 . The method of  claim 26  further comprising placing a separator between the cathode and an anode.  
     
     
         29 . The method of  claim 28  wherein the separator comprises a porous polymer or a solid electrolyte.  
     
     
         30 . The method of  claim 26  wherein the battery comprises a plurality of cathodes.  
     
     
         31 . A battery comprising a cathode having silver vanadium oxide particles, a binder and at least about 10 weight percent electrically conductive, electro-chemically inert particles, wherein the cathode has a thickness of at least about 0.8 mm.  
     
     
         32 . The battery of  claim 31  wherein the cathode comprises at least about 15 weight percent electrically conductive, electrochemically inert particles.  
     
     
         33 . The battery of  claim 31  wherein the cathode comprises at least about 20 weight percent electrically conductive, electrochemically inert particles.  
     
     
         34 . The battery of  claim 31  wherein the anode comprises lithium metal and the battery exhibits no significant voltage delay under pulsed operation at about 2.6 volts.  
     
     
         35 . The battery of  claim 31  wherein the electrical resistance does not increase substantially upon discharge to 1.5 volts.  
     
     
         36 . The battery of  claim 31  wherein the electrically conductive, electrochemically inert particles comprise silver particles with an average diameter less than 1000 nm.  
     
     
         37 . The battery of  claim 31  wherein the electrically conductive, electrochemically inert particles comprise carbon particles.  
     
     
         38 . The battery of  claim 31  wherein the cathode has a density from about 1.8 g/cc to about 2.8 g/cc.  
     
     
         39 . The battery of  claim 31  wherein the battery can supply current pulses at a rate of at least 50 mA/cm 2 .  
     
     
         40 . The battery of  claim 31  having a pulse specific capacity of at least about 275 mAh/g to 1.5 volts.  
     
     
         41 . The battery of  claim 31  wherein the anode comprises elemental lithium metal.  
     
     
         42 . An implantable medical device comprising a battery of  claim 31 .  
     
     
         43 . A battery comprising a cathode comprising silver vanadium oxide particles, a binder and at least about 10 weight percent electrically conductive, electro-chemically inert particles, wherein the cathode has a density from about 1.8 g/cc to about 2.8 g/cc.  
     
     
         44 . The battery of  claim 43  wherein the cathode comprises at least about 15 weight percent electrically conductive, electrochemically inert particles.  
     
     
         45 . The battery of  claim 43  wherein the cathode has a density from about 2.4 g/cc to about 2.8 g/cc.  
     
     
         46 . The battery of  claim 43  wherein the electrical resistance does not increase substantially upon discharge to 1.5 volts.  
     
     
         47 . The battery of  claim 43  wherein the anode comprises lithium metal and the battery exhibits no significant voltage delay under pulsed operation at about 2.6 volts.  
     
     
         48 . The battery of  claim 43  wherein the electrically conductive, electrochemically inert particles comprise carbon particles.  
     
     
         49 . The battery of  claim 43  further comprising an anode wherein the anode comprises elemental lithium metal.  
     
     
         50 . The battery of  claim 43  wherein the silver vanadium oxide particles have an average diameter less than about 1000 nm.  
     
     
         51 . The battery of  claim 43  wherein the silver vanadium oxide particles comprise Ag x V 2 O y , with 0.3≦x≦2.0 and 4.5≦y≦6.0.  
     
     
         52 . The battery of  claim 43  having a pulse specific capacity of at least about 275 mAh/g to 1.5 volts.  
     
     
         53 . The battery of  claim 43  wherein the binder comprises polyvinylidene fluoride, polyethylene oxide, polyethylene, polypropylene, polytetrafluoro ethylene, polyacrylates, ethylene-(propylene-diene monomer) copolymer (EPDM), mixtures thereof or copolymers thereof.  
     
     
         54 . An implantable medical device comprising the battery of  claim 43.