ENCAPSULATION OF HIGH TEMPERATURE THERMOELECTRIC MODULES

摘要

A method of encapsulating a thermoelectric device and its associated thermoelectric elements in an inert atmosphere and a thermoelectric device fabricated by such method are described. These thermoelectric devices may be intended for use under conditions which would otherwise promote oxidation of the thermoelectric elements. The capsule is formed by securing a suitably-sized thin-walled strip of oxidation-resistant metal to the ceramic substrates which support the thermoelectric elements. The thin-walled metal strip is positioned to enclose the edges of the thermoelectric device and is secured to the substrates using gap-filling materials. The strip, substrates and gap-filling materials cooperatively encapsulate the thermoelectric elements and exclude oxygen and water vapor from atmospheric air so that the elements may be maintained in an inert, non-oxidizing environment.

主权项

1. A method of fabricating a thermoelectric device intended for use at elevated temperatures in an oxidizing environment, the device comprising a plurality of like-shaped, electrically-interconnected, thermoelectric elements, each having opposed mounting faces spaced apart by a generally common length; and, a plurality of air impervious ceramic substrates comprising one low-temperature side substrate adapted for thermal communication with a heat sink, and one or more high temperature-side substrates adapted for thermal communication with a heat source, each of the substrates being thermally conducting and electrically insulating and each of the substrates incorporating one or more electrical interconnects, the method comprising:
arranging the thermoelectric elements in a predetermined assembly pattern in which the thermoelectric elements are spaced apart with their opposed mounting faces in contact with the electrical interconnects on opposing substrates to form an assembly, each of the elements and high temperature-side substrates being spaced apart and separated by gaps, and at least the high temperature-side substrates being shaped and arranged with a perimeter adapted to promote thermal communication between a shaped heat source and a heat source-contacting surface of the one or more substrates; positioning a continuous, upstanding, thin-walled, oxidation-resistant metal shield around the perimeter of the assembly, the shield comprising a wall with a width and first and second edges, the first edge being aligned with the heat source-contacting surface of the one or more high temperature-side substrates and the wall extending toward the low temperature-side substrate, the wall outlining an opening shaped and sized substantially like, but larger than, the perimeter of the assembly, so that a gap is formed between the shield wall and the assembly perimeter, the wall having a width predetermined to maintain the second wall edge in spaced apart relation to the low temperature-side substrate to create an opening between the low temperature-side substrate and the second wall edge; then sealing the gaps between the individual high temperature-side substrates and gap between the high temperature side substrate perimeter and the shield wall with an air-impervious vitreous enamel, by applying a gap-filling quantity of vitreous enamel powder or vitreous enamel precursor powder to all gaps, firing the vitreous enamel powder or enamel-precursor powder at pre-determined temperature to form a flowable enamel, and maintaining the predetermined temperature for a time sufficient to flow the enamel, fill all gaps with enamel, and bond the enamel to the substrates and the shield; cooling the assembly, shield and enamel to about room temperature to solidify the enamel; and applying a quantity of a flowable, low temperature-curable polymer or a thermoplastic polymer sufficient to fill the opening between the second edge of the metal shield and the low temperature-side substrate; and curing or solidifying the curable polymer or cooling the thermoplastic to form a continuous air-excluding barrier which cooperates with the one or more high temperature-side substrates, the low temperature-side substrate, the vitreous enamel and the shield to prohibit ingress of atmospheric air to the thermoelectric elements of the device.