Hermetically sealed wet electrolytic capacitor

Abstract

A hermetically sealed wet electrolytic capacitor includes a hermetically sealed case, a cathode, an anode, and an insulator between the anode and the cathode to provide electrical insulation between the anode and the cathode. An electrolytic solution is disposed within the case. A first terminal is electrically connected to the anode and a second terminal is electrically connected to the cathode. The cathode comprises a metal substrate having an alloy layer formed with a noble metal and a noble metal/base metal electrode element layer electrochemically deposited thereon. The electrolytic solution has a conductivity between 10 and 60 mS/cm. The capacitor may be used in an implantable device.

1 . A hermetically sealed wet electrolytic capacitor, comprising:
 a hermetically sealed case;   a cathode having a first terminal;   an anode having a second terminal;   an insulator between the anode and the cathode for providing electrical insulation between the anode and the cathode; and   an electrolytic solution disposed within the case;   wherein the hermetically sealed wet electrolytic capacitor is adapted to delivery at least 80 percent of stored energy between the first and second terminals.   
     
     
         2 . The hermetically sealed wet electrolytic capacitor of  claim 1  wherein the cathode comprises a metal substrate having an alloy layer formed with a noble metal and a noble metal/base metal electrode element layer electrochemically deposited thereon. 
     
     
         3 . The hermetically sealed wet electrolytic capacitor of  claim 2  wherein the metal substrate comprises a valve metal. 
     
     
         4 . The hermetically sealed wet electrolytic capacitor of  claim 3  wherein the metal substrate comprises tantalum, niobium, hafnium, zirconium, titanium or alloys thereof. 
     
     
         5 . The hermetically sealed wet electrolytic capacitor of  claim 1  wherein the electrolytic solution has conductivity between 10 and 60 mS/cm. 
     
     
         6 . The hermetically sealed wet electrolytic capacitor of  claim 5  wherein the electrolytic solution comprises water, inorganic acids (phosphoric and boric), an organic acid (oxalic) and an organic solvent. 
     
     
         7 . An implantable device including the hermetically sealed wet electrolytic capacitor of  claim 1 . 
     
     
         8 . An implantable cardioverter defibrillator (ICD) including the hermetically sealed wet electrolytic capacitor of  claim 1 . 
     
     
         9 . An implantable device including:
 a battery;   a processor coupled to the battery; and   a capacitor coupled to the battery and the processor, including;
 a hermetically sealed case; 
 a cathode including a first terminal; 
 an anode including a second terminal; 
 an insulator between the anode and the cathode which provides electrical insulation between the anode and the cathode; and 
 an electrolytic solution disposed within the case having conductivity between 10 and 60 mS/cm; 
 wherein the cathode comprises a metal substrate having an alloy layer formed with a noble metal and a noble metal/base metal electrode element layer electrochemically deposited thereon; and 
 whereby the capacitor is adapted to provide at least 80% of its stored energy between said first and second terminals in a single discharge. 
   
     
     
         10 . The hermetically sealed wet electrolytic capacitor of  claim 9  wherein the metal substrate comprises a valve metal. 
     
     
         11 . The hermetically sealed wet electrolytic capacitor of  claim 10  wherein the metal substrate comprise tantalum, niobium, hafnium, zirconium, titanium or alloys thereof. 
     
     
         12 . The hermetically sealed wet electrolytic capacitor of  claim 9  wherein the electrolytic solution comprises water, inorganic acids (phosphoric and boric), an organic acid (oxalic) and an organic solvent. 
     
     
         13 . The hermetically sealed wet electrolytic capacitor of  claim 9  being adapted to provide pulse delivery of at least 80 percent, preferably greater than 87 percent, of stored energy to the first and second terminals. 
     
     
         14 . An implantable device comprising the hermetically sealed wet electrolytic capacitor of  claim 9 . 
     
     
         15 . An implantable cardioverter defibrillators (ICD) comprising the hermetically sealed wet electrolytic capacitor of  claim 9 . 
     
     
         16 . A method of manufacturing a capacitor, comprising:
 hermetically sealing a case wherein an electrolytic solution being disposed within the case, the electrolytic solution having a conductivity between 10 and 60 mS/cm;   electrically connecting a first terminal to an anode, the anode being insulated from a cathode; and   electrically connecting a second terminal to the cathode, the cathode comprising a metal substrate having an alloy layer formed with a noble metal and a noble metal/base metal electrode element layer electrochemically deposited thereon.   
     
     
         17 . The method of  claim 16  further comprising preparing the electrolytic solution by admixing water, inorganic and organic acids, and an organic solvent.