Thermoelectric converter with projecting cell stack

Abstract

A thermoelectric converter is formed by a plenum divided into high and low pressure chambers by a partition and includes a stack of series-coupled alkali-metal thermoelectric cells that projects orthogonally from the partition into one of the chambers.

What is claimed is: 
     
         1 . A thermoelectric converter comprising:
 a housing;   a partition that divides an interior region of the housing into first and second chambers; and   a thermoelectric cell stack disposed over an opening in the partition and projecting orthogonally from the partition into the first chamber without contacting the housing such that the cell stack is free to expand and contract in the projecting direction, the thermoelectric cell stack having a plurality of alkali-metal thermoelectric conversion cells stacked on one another and electrically coupled in series to generate a collective voltage higher than a voltage generated by any one of the thermoelectric conversion cells.   
     
     
         2 . The thermoelectric converter of  claim 1  further comprising a lid coupled to an end of the thermoelectric cell stack furthest from the partition, the lid separating an interior region of the thermoelectric cell stack from the first chamber. 
     
     
         3 . The thermoelectric converter of  claim 2  wherein the housing is electrically coupled to an initial one of the thermoelectric conversion cells in the thermoelectric cell stack to form a first electric terminal of the thermoelectric converter, and wherein the lid is electrically coupled to a final one of the thermoelectric conversion cells in the thermoelectric cell stack, the thermoelectric converter further comprising a conductor extending from the lid to a point outside the housing to form a second electric terminal of the thermoelectric converter. 
     
     
         4 . The thermoelectric converter of  claim 2  wherein the plurality of thermoelectric conversion cells in the thermoelectric cell stack are mechanically joined to seal the interior region of the thermoelectric cell stack from the first chamber. 
     
     
         5 . The thermoelectric converter of  claim 1  wherein the housing comprises a vapor input to receive a flow of alkali metal vapor into the first chamber such that the first chamber is at a higher pressure than the second chamber, the pressure differential between the first and second chambers exerting a compression force on joints between the plurality of thermoelectric conversion cells. 
     
     
         6 . The thermoelectric converter of  claim 1  further comprising a mounting member that secures and electrically couples an initial one of the thermoelectric conversion cells in the thermoelectric cell stack to the partition. 
     
     
         7 . The thermoelectric converter of  claim 6  wherein the mounting member is malleable to permit the thermoelectric cell stack to thermally expand and contract at a different rate than the partition without disruptive stress. 
     
     
         8 . The thermoelectric converter of  claim 7  wherein the mounting member, partition and housing are electrically conductive such that the housing and the initial one of the thermoelectric conversion cells are at nominally the same electric potential. 
     
     
         9 . The thermoelectric converter of  claim 1  further comprising a plurality of additional thermoelectric cell stacks disposed respectively over additional openings in the partition, each additional thermoelectric cell stack projecting orthogonally from the partition into the first chamber without contacting the housing. 
     
     
         10 . The thermoelectric converter of  claim 1  wherein adjacent first and second thermoelectric conversion cells of the plurality of thermoelectric conversion cells are mounted to one another and each include a solid electrolyte member disposed between an anode and a cathode, and wherein the thermoelectric cell stack comprises:
 an electrical interconnect structure extending from the cathode of the first thermoelectric conversion cell to the anode of the second thermoelectric conversion cell; and 
 a first electrically insulating barrier disposed between the anode of the first thermoelectric conversion cell and the electrical interconnect structure, the first electrically insulating barrier projecting away from an outer surface of the first thermoelectric conversion cell by a distance substantially greater than a thickness of the anode of the first thermoelectric conversion cell. 
 
     
     
         11 . The thermoelectric converter of  claim 10  wherein the thermoelectric cell stack further comprises a second electrically insulating barrier disposed between the cathode of the second thermoelectric conversion cell and the electrical interconnect structure and projecting away from the second thermoelectric conversion cell in a direction opposite the projection of the first electrically insulating barrier. 
     
     
         12 . A method of operation within a thermoelectric converter having a housing divided into first and second chambers by a partition, the method comprising:
 receiving a flow of alkali-metal vapor into the first chamber to produce a pressure differential between the first and second chambers; and   generating an electric potential by conducting alkali metal ions from the first chamber to the second chamber through solid electrolyte members of respective thermoelectric conversion cells coupled electrically in series and stacked over an opening in the partition to form a thermoelectric cell stack that projects orthogonally from the partition into the first chamber without contacting the housing, the electric potential being proportional to the number of thermoelectric conversion cells within the thermoelectric cell stack.   
     
     
         13 . The method of  claim 12  wherein generating the electric potential by conducting alkali metal ions from the first chamber to the second chamber comprises generating the electric potential by conducting the alkali metal ions from the first chamber to an interior region of the thermoelectric cell stack. 
     
     
         14 . The method of  claim 12  wherein generating the electric potential by conducting alkali metal ions from the first chamber to the second chamber comprises ionizing alkali-metal vapor to separate the alkali metal ions from corresponding electrons, the method further comprising conducting the electrons to a first terminal of the thermoelectric converter via a conduction path exterior to the thermoelectric cell stack. 
     
     
         15 . The method of  claim 14  further comprising receiving electrons via a second terminal of the thermoelectric converter, the second terminal being electrically coupled to and at the same electric potential as one of the thermoelectric conversion cells at an end of the thermoelectric cell stack furthest from the partition. 
     
     
         16 . The method of  claim 15  further comprising forming alkali metal vapor within the second chamber by recombining the electrons received via the second terminal with the alkali metal ions conducted to the second chamber through the solid electrolyte members of respective thermoelectric conversion cells. 
     
     
         17 . The method of  claim 16  further comprising condensing the alkali-metal vapor formed within the second chamber into liquid metal and pumping the liquid metal out of the second chamber to be vaporized and returned to the first chamber. 
     
     
         18 . The method of  claim 17  wherein condensing the alkali-metal vapor formed within the second chamber into liquid metal comprises collecting the liquid metal in a pool at an end of the housing opposite from an end of the housing toward which the thermoelectric cell stack projects. 
     
     
         19 . The method of  claim 12  further comprising applying a heat source to an exterior surface of the housing opposite the first chamber to maintain the first chamber at a temperature that prevents the alkali-metal vapor received within the first chamber from condensing on the thermoelectric cell stack. 
     
     
         20 . A thermoelectric converter comprising:
 a housing;   means for dividing the housing into first and second chambers;   means for receiving a flow of alkali-metal vapor into the first chamber to produce a pressure differential between the first and second chambers; and   means for generating an electric potential by conducting alkali metal ions from the first chamber to the second chamber via respective thermoelectric conversion cells coupled electrically in series and stacked over an opening in means for dividing the housing to form a thermoelectric cell stack that projects from the means for dividing the housing into the first chamber without contacting the housing, the electric potential being proportional to the number of thermoelectric conversion cells within the thermoelectric cell stack.