Low power thermoelectric generator
View Patent ↗A thermoelectric generator has a top plate disposed in spaced relation above a bottom plate. A series of foil segments are electrically and mechanically connected end-to-end to generate a foil assembly that is spirally wound and in thermal contact with the bottom and top plates. Each foil segment comprises a substrate having a series of spaced alternating n-type and p-type thermoelectric legs disposed in parallel arrangement on the front substrate surface. Each of the n-type and p-type legs is formed of a bismuth telluride-based thermoelectric material having a thickness of about 10-100 microns, a width of about 10-100 microns and a length of about 100-500 microns. The alternating n-type and p-type thermoelectric legs are electrically connected in series and thermally connected in parallel such that a temperature differential between the bottom and top plates results in the generation of power.
1. A method of producing a foil assembly for a thermoelectric generator, comprising the steps of:
providing substrate material having front and back substrate surfaces;
depositing an array of n-type and p-type thermoelectric legs onto at least one of the front and back substrate surfaces;
depositing metal bridges on at least one of the front and back substrate surfaces to interconnect the n-type and p-type thermoelectric legs;
cutting the substrate material having the n-type and p-type thermoelectric legs and metal bridges deposited thereon in such a manner to form a plurality of foil segments;
providing at least one connector;
aligning a pair of the foil segments in series for joining in end-to-end contact with one another to form a foil joint;
mechanically interconnecting the foil segments in end-to-end contact in the same plane with one another to form a single, elongate foil assembly by bonding the connector across the foil joint on at least one of the front and back substrate surfaces of the end-to-end foil segments with electrically non-conductive and thermally low conductive assembly adhesive; and
electrically interconnecting the foil segments on at least one of the front and back substrate surfaces in an electrically redundant manner using electrically conductive adhesive to electrically connect an endmost pair of the n-type and p-type thermoelectric legs of one of the foil segments to an endmost pair of the n-type and p-type thermoelectric legs of an adjacent one of the foil segments along at least one of the top and bottom edges of the foil segments; and
spirally winding the foil assembly into a generally round shape.
2. The method of claim 1 , wherein:
the front substrate surface of the foil segments face radially inwardly.
3. The method of claim 1 wherein:
the n-type and p-type thermoelectric legs are deposited onto the substrate using a series of alternating hot and cold sputtering steps;
the cold sputtering step being performed at a temperature of in the range of from about 10° Celsius to about 100° Celsius;
the hot sputtering step being performed at a temperature in the range of from about 200° Celsius to about 400° Celsius.
4. The method of claim 1 further comprising the step of:
depositing metal contacts along at least one of top and bottom edges of the connector by sputtering a layer of nickel onto the connector followed by evaporation of a layer of gold onto the nickel layer.
5. The method of claim 1 further comprising the step of:
depositing end contacts along at least one of the top and bottom edges of at least one of the front and back substrate surfaces of the foil segments at opposing free ends thereof.
6. The method of claim 1 further comprising the step of:
cutting the substrate material to form the connector.