Preliminary Fabrication Of Thermoelectric Generator With PN Laminated Structure

Thermoelectric generator can convert heat to electricity directly, and because of its advantages such as no pollution, long service life and high reliability, it has a broad application prospect in the waste heat recovery and geothermal development, it is also very important for the development of national economy.Commercial thermoelectric generators, with metal to connection P-type arm and n-type arm, can only be used at low temperature. At high temperature, the oxidization of conneting metal, the thermal stress fatigue and slow atomic diffusion between the metal contact and semiconductor would induce the failure of thermoelectric generators. Metal thermal oxidation can be avoided problem by contacting P-arm with N-arm directly, but atomic diffusion, thermal stress fatigue remained. Atomic diffusion would increase the resistance at the contact surface, and reduce the output power of generator. The paper presents a new U-type thermoelectric generator with P-type semiconductor and N-type semiconductor laminated structure as the connection of P-arm and N-arm, this design reduces the contact resistance by increasing the contact area, and avoiding the direct cracking at the contact by changing the direction of thermal stress.In this paper, P-type Ca₃Co₄O₉ and n-type CaMnO₃ thermoelectric materials have been synthesized by using solid state reaction route and sol-gel method respectively, and Ca₃Co₄O₉ and CaMnO₃ bulk thermoelectric materials sintered, too. At the same time, a set of thermoelectric test equipment has been set up to measure the resistance and output power of samples in simulated conditions; a CaMnO₃ sample with the output power of 13mW has been obtained. At last, a new U-type thermoelectric generator has been fabricated by which many process difficulties have been presented, and more efforts should be paid on it.