Thin-film thermoelectric generators with a novel folding scheme are proposedfor large-area, low energy density applications. Both the electrical currentand heat transfer are in the plane of the thermoelectric thin-film, yet theheat transfer is across the plane of the thermoelectric module - similar to aconventional bulk thermoelectric module. With such a design, the heat leakagethrough the module itself can be minimized and the available temperaturegradient maximized. Different from the previously reported corrugatedthermoelectric generators, the proposed folding scheme enables high packingdensities without compromising the thermal contact area to the heat source andsink. The very thin thermoelectric films (400 nm) and modest temperaturegradients applied are shown to set some unconventional prerequisite for thedesign: the performance cannot be optimized by concentrating on maximizing theoutput power. Instead, specific attention has to be paid to the currentproduction properties to enable practical applications. Various design aspectsand their influence on the thermal transport mechanisms under heat sink limitedconditions are analyzed and their (complex) impact on the performancehighlighted. Further, it is shown that ZT describing the material properties isnot always a good measure for predicting the power production of such thin-filmdevices.
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