Miniature electrochemical cell having a casing of a metal container closed with a ceramic plate having two via holes supporting opposite polarity platinum-containing conductive pathways

An electrochemical cell, comprising:

• a) a casing, comprising:
• i) an open-ended container of an electrically conductive material;
• ii) a header comprising a ceramic plate hermetically secured to an outer annular metallic ring by a gold-braze, the ceramic plate having a ceramic plate inner surface opposite a ceramic plate outer surface;
• iii) a first electrically conductive pathway and a second electrically conductive pathway, both conductive pathways comprising a platinum-containing fill material residing in a respective first and second via holes extending through the ceramic plate, wherein the first and second conductive pathways each having a conductive pathway inner surface located at or adjacent to the ceramic plate inner surface and a conductive pathway outer surface located at or adjacent to the ceramic plate outer surface;
• and
• iv) a weld hermetically securing the outer annular ring of the header to the open end of the container;
• and
• b) an electrode assembly, comprising:
• i) a cathode current collector contacted to the ceramic plate inner surface at the first conductive pathway inner surface;
• ii) a cathode active material conductively contacted to the cathode current collector opposite the first conductive pathway in the first via hole, the cathode active material having an outer peripheral edge, wherein the cathode active material is either LiCoO2 or LiNiaMnbCo1-a-bO2;
• iii) a solid electrolyte that curves over and around the cathode active material including its outer peripheral edge so that the solid electrolyte contacts the inner surface of the ceramic plate, wherein the solid electrolyte is LixPOyNz with x ranging from 3 to 4, y ranging from 3 to 4, and z ranging from 0.1 to 1;
• iv) an anode current collector contacted to the ceramic plate inner surface at the second conductive pathway, the anode current collector spaced from the cathode current collector;
• and
• v) an anode a cathode active material contacting the solid electrolyte opposite the cathode active material, the anode active material conductively contacted to the anode current collector opposite the second conductive pathway in the second via hole extending through the ceramic plate of the header,
• c) wherein the outer surfaces of the first and second conductive pathways are configured for electrical connection to a load.

A method for providing an electrochemical cell, comprising the steps of:

• a) providing an open-ended container of an electrically conductive material;
• b) providing a ceramic plate having a ceramic plate inner surface opposite a ceramic plate outer surface;
• c) providing an outer annular metallic ring and gold brazing the ceramic plate in the ring to thereby form a header;
• d) providing a first via hole and a second via hole extending through the ceramic plate to the ceramic plate inner and outer surfaces;
• e) filling a paste of a platinum-containing material into the first and second via holes and then heating the ceramic plate to transform the paste into first and second platinum-containing fill materials hermetically sealed to the ceramic plate in the respective first and second via holes, wherein the first and second platinum-containing fill materials each comprise a platinum-containing fill material inner surface located at or adjacent to the ceramic plate inner surface and a platinum-containing fill material outer surface located at or adjacent to the ceramic plate outer surface;
• f) contacting a first current collector to the inner surface of the ceramic plate at the first platinum-containing fill material in the first via hole;
• g) contacting a second current collector to the inner surface of the ceramic plate at the second platinum-containing fill material in the second via hole, the first and second current collectors being spaced from each other;
• h) depositing a first active material onto the first current collector opposite the first platinum-containing fill material in the first via hole, the first active material having an outer peripheral edge;
• i) depositing a solid electrolyte layer onto the first active material, the solid electrolyte curving over and around the first active material including its outer peripheral edge so that the solid electrolyte contacts the inner surface of the ceramic plate;
• depositing a second, opposite polarity active material onto the solid electrolyte opposite the second first active material, the second active material conductively contacted to the second current collector opposite the second conductive pathway in the second via hole extending through the ceramic plate of the header;
• and
• k) welding the annular ring of the header to the open end of the container to thereby provide a casing housing the first and second active materials prevented from direct physical contact with each other by the solid electrolyte layer,
• l) wherein the outer surfaces of the first and second platinum-containing fill materials are configured for electrical connection to a load.