Conference Program - LOPE-C 2011

SCIENTIFIC CONF. | WEDNESDAY-JUNE 29, 2011
Track 5
Sensors and Systems (11:30 am - 01:20 pm) | LOCATION HARMONIE E / LEVEL C2
01:00 pm Screen printed thermoelectric generator in a five layers vertical setup
Mr Andreas Willfahrt,
Stuttgart Media University, Research Assistant, Germany
The development of a screen printed thermoelectric generator (TEG) consisting of five functional layers will be presented. In the governmentally funded research project
?Printed Thermoelements? screen printing is used instead of the complex conventional production process to assemble TEGs. The major challenge is the need for
appropriate printing inks comprising of rather exotic functional particles dispersed in binders and solvents to render them printable. Unfortunately, the classic materials like
bismuth telluride (Bi2Te3) which can be either n- or p-doped is not used here since there are no printing inks available. The deployed materials show a smaller Seebeck
coefficient than Bi2Te3 but they are optimized for printing. In the author?s opinion the results achieved with the deployed materials can easily be adopted to other material
combinations including a printing ink consisting of Bi2Te3 particles, which might be developed in the future.
The thermoelectric generator to be presented comprises of printed silver ink conductors (top and bottom conductors), an insulating mask-layer with cavities permeated by
two different thermoelectric materials. A self-prepared Nickel ink is used for the n-type leg whereas the p-type leg consists of the conductive polymer Clevios SV3
(PEDOT/PSS). The cavities formed by the square apertures in the insulating mask will be filled with the p- and n-type thermoelectric materials in subsequent print runs.
From some tens to hundreds of such thermocouples are connected in series to form a thermoelectric generator. Especially in the layout of the TEG the printing technology
reveals its superiority.
The insulating (electrically and thermal) mask-layer must be printed with a high layer thickness (about 100 µm or more) in order to separate the heat source and heat sink to
maintain the needed temperature gradient. The large layer thickness requires appropriate techniques for preparing the stencils for these printing steps. This will be
explained in the presentation.
01:20 pm LUNCH BREAK
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