High Efficiency Thin Film Thermoelectric Generators (HiE TFTEGs) for Vehicles

A significant portion of the waste heat from engine exhaust can be recovered using thermoelectric generators to achieve up to 10% gain in automotive mileage. There have been several efforts underway on this front but most have focused on demonstrating thermoelectric generators using bulk materials that consume significant amount of raw materials and are prone to failures due to thermal expansion, oxidation, and change in stoichiometry due to diffusion. Furthermore, the heat flux and power generation in the bulk TEGs are limited due to large transport lengths of the carriers, and often result in large form factors that are impractical for vehicles. We propose the development of efficient, segmented, and graded thin film thermoelectric generators (TFTEG) that builds upon established semiconductor fabrication techniques that can be scaled up for high volume production. The low materials usage and batch fabrication afforded by the thin film technology will result in ultra-low cost metrics ( & lt;$0.1/W). We propose to integrate skutterudites that have been perfected by the NASAs Jet Propulsion Lab with Bi chalcogenides, Zn4Sb3 and other proprietary films developed at Sheetak. This research effort will make the best available thermoelectric generator technology affordable for commercialization. As the end of Phase II of this work, Sheetak will demonstrate thermoelectric generators with ZT & gt;1.6 across a broad temperature range of 30C - 650C and the proposed TFTEG will be the highest performance TEG at the most affordable price.