Secondary interconnect for fuel cell systems

A segmented-in-series fuel cell system comprising:

• a substrate having a first major surface second major surface;
• a fuel channel disposed between the first and second major surfaces, wherein the fuel channel is separated from the first and second major surfaces by the substrate;
• a first and second electrochemically active fuel cells disposed on the first major surface and a third and fourth electrochemically active fuel cells disposed on the second major surface, each of said electrochemically active fuel cells comprising:
• an anode;
• a cathode;
• and
• an electrolyte disposed between said anode and said cathode;
• a first primary interconnect electrically coupling the anode of the first electrochemically active fuel cell to the cathode of the second electrochemically active fuel cell;
• a second primary interconnect electrically coupling the anode of the third electrochemically active fuel cell to the cathode of the fourth electrochemically active fuel cell;
• a first electrochemically inactive cell disposed on the first major surface and a second electrochemically inactive cell disposed on the second major surface, each of the electrochemically inactive cells comprising a conductive layer electrically coupled to at least one of the electrochemically active fuel cells;
• and
• a secondary interconnect electrically coupled to the conductive layer of the first and second electrochemically inactive cells,
• wherein the electrochemically inactive cells are configured to inhibit migration of hydrogen from the fuel channel to the secondary interconnect.

A fuel cell tube comprising:

• a substrate having a major surface;
• a fuel channel separated from the major surface by the substrate;
• at least one electrochemically active cell disposed on the major surface comprising:
• an anode;
• a cathode;
• and
• an electrolyte disposed between the anode and the cathode;
• an electrochemically inactive cell disposed on the major surface, the electrochemically inactive cell comprising:
• a conductive layer;
• an electrolyte disposed between said conductive layer and the major surface of said substrate;
• and
• a dense barrier disposed between the electrolyte and the major surface of said substrate;
• and
• a primary interconnect electrically coupling the anode of the electrochemically active cell and the conductive layer;
• and
• a secondary interconnect comprising palladium electrically coupled to the conductive layer of the electrochemically inactive cell, wherein the secondary interconnect is at least partly buried by a conductive bonding paste.