High-energy density miniature thermoelectric generator using catalytic combustion

This paper describes the components and system of a thermoelectric (TE) generator with a catalytic butane combustor. The combustion chamber with a size of 8 mm×8 mm×0.4 mm is etched in a 0.65-mm-thick silicon substrate, and bonded to both sides of a 0.77-mm-thick glass substrate with a thin-film ignition heater. A set of 34 couples of BiTe TE elements, each with a size of 0.65 mm×0.65 mm×2 mm, are directly bonded to both sides of the combustor. The combustor without the TE modules was tested using butane as fuel, and self-sustaining combustion and electrical ignition were achieved. Also, nearly 100% combustion efficiency and a uniform temperature distribution were confirmed by gas chromatography and infrared thermoimaging, respectively. When the TE modules were attached to the combustor, however, butane combustion was impossible. The characteristics of TE generation were measured using hydrogen as fuel. When a theoretical combustion power was 6.6 W, the maximum output power of 184 mW was obtained with a load of 5.68 Ω. The total efficiency in this experiment was 2.8% (184 mW/6.6 W).