Methods of manufacturing a hermetically sealed wet electrolytic capacitor and a hermetically sealed wet electrolytic capacitor
Methods of manufacturing a hermetically sealed wet electrolytic capacitor and a hermetically sealed wet electrolytic capacitor are described. A method of manufacturing a wet electrolytic capacitor includes forming a cathode of the capacitor by forming a case comprising a metal substrate, the metal substrate having an alloyed surface, depositing a smooth film comprising palladium and copper as a tacking layer on the alloyed surface of the metal substrate, and depositing a rough, high surface area layer on the tacking layer to achieve a high capacitance cathode. A first terminal is electrically connected to the cathode. An anode is formed. A second terminal is electrically connected to the anode. An electrolytic solution is disposed within the case, and the case is hermetically sealed.
1. A method of manufacturing a hermetically sealed wet electrolytic capacitor, the method comprising:
forming a cathode of the capacitor by:
forming a case comprising a metal substrate, the metal substrate being formed from a valve metal and having a titanium and palladium alloyed surface,
depositing a smooth film comprising palladium and copper as a tacking layer on the alloyed surface of the metal substrate,
depositing a rough layer on the tacking layer to achieve a high capacitance cathode;
electrically connecting a first terminal to the cathode;
forming an anode;
electrically connecting a second terminal to the anode;
disposing an electrolytic solution within the case; and
hermetically sealing the case.
2. The method of claim 1 , further comprising: positioning an insulator between the cathode and the anode.
3. The method of claim 1 , wherein the metal substrate comprises a titanium alloy.
4. The method of claim 1 , further comprising forming the anode from sodium reduced capacitor grade tantalum powder pressed to a green density of between 5.0 and 7.0 grams/cc and then vacuum sintered between 1450 degrees Celsius and 1650 degrees Celsius.
5. The method of claim 1 , wherein the electrolytic solution has conductivity between 10 and 60 mS/cm.
6. The method of claim 1 , wherein the electrolytic solution comprises water, inorganic acids, an organic acid and an organic solvent.
7. A hermetically sealed wet electrolytic capacitor comprising:
a hermetically sealed capacitor case comprising a multi-layer cathode, the multi-layer cathode comprising:
a metal substrate formed from a valve metal and having a titanium and palladium alloyed surface layer,
a smooth film comprising palladium and copper deposited on the alloyed surface layer as a tacking layer, and
a rough layer deposited on the tacking layer and configured to achieve high capacitance;
an anode disposed in the hermetically sealed capacitor case; and
an electrolytic solution disposed in the hermetically sealed capacitor case.
8. The hermetically sealed wet electrolytic capacitor of claim 7 , further comprising:
an insulator disposed between the cathode and the anode.
9. The hermetically sealed wet electrolytic capacitor of claim 7 , wherein the metal substrate comprises a titanium alloy.
10. The hermetically sealed wet electrolytic capacitor of claim 7 , wherein the anode comprises sodium reduced capacitor grade tantalum powder pressed to a green density of between 5.0 and 7.0 grams/cc and then vacuum sintered between 1450 degrees Celsius and 1650 degrees Celsius.
11. The hermetically sealed wet electrolytic capacitor of claim 7 , wherein the electrolytic solution has conductivity between 10 and 60 mS/cm.
12. The hermetically sealed wet electrolytic capacitor of claim 7 , wherein the electrolytic solution comprises water, inorganic acids, an organic acid and an organic solvent.
13. A method of manufacturing a hermetically sealed wet electrolytic capacitor, the method comprising:
providing a case formed from a valve metal having a titanium and palladium alloyed inner surface;
forming a cathode on the alloyed inner surface of the case, the cathode comprising multiple layers, at least one of the cathode layers comprising a smooth film comprising palladium and copper as a tacking layer deposited on the alloyed inner surface of the case;
disposing an anode within the case,
electrically connecting a first terminal to an anode, the anode being insulated from the cathode;
electrically connecting a second terminal to the cathode;
disposing an electrolytic solution within the case; and
hermetically sealing the case;
wherein the amount of energy delivered by the capacitor is greater than 87 percent of the stored energy of the capacitor.
14. The method of claim 13 , further comprising preparing the electrolytic solution by admixing DI water, phosphoric acid, ethylene glycol and boric acid.
15. The method of claim 13 , wherein the step of forming the cathode comprises depositing a layer on the tacking layer, wherein the layer has a rough surface.
16. The method of claim 13 , further comprising: positioning an insulator between the cathode and the anode.
17. The method of claim 13 , wherein the alloyed inner surface comprises a titanium alloy.
18. The method of claim 13 , further comprising forming the anode from sodium reduced capacitor grade tantalum powder pressed to a green density of between 5.0 and 7.0 grams/cc and then vacuum sintered between 1450 degrees Celsius and 1650 degrees Celsius.
19. The method of claim 13 , wherein the electrolytic solution has conductivity between 10 and 60 mS/cm.