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The newly developed, semi-automated pilot production of high-temperature thermoelectric modules enables significantly higher volumes to be produced than the previously conventional manual production.
© Fraunhofer IPM
Thermoelectrics
11.08.2016

Various thermoelectric modules produced by the pilot production. The scale of the modules shown ranges from a sugar cube to a matchbox size (16 x 16 mm or 40 x 40 mm).
© Fraunhofer IPM

Pilot production of thermoelectric modules

Thermoelectric generators convert waste heat directly into electricity. They utilise temperature differences and are paving the way for more energy-efficient production processes. However, the technology has previously led a niche existence because the module production is labour-intensive and therefore expensive. Researchers from Freiburg now want to improve this.

At the end of July 2016, the scientists began operating a new, semi-automated pilot production plant for high-temperature thermoelectric modules at the Fraunhofer Institute for Physical Measurement Techniques IPM. They want to use it to make these modules cheaper. Dr Jan König, Group Leader Thermoelectrics at the Fraunhofer Institute for Physical Measurement Techniques, emphasises: "We have taken an important step with the pilot production plant. We are demonstrating on a laboratory scale that thermoelectric modules can be automatically produced in series. These were previously made very elaborately by hand." The automated production reduces the manufacturing costs by about three quarters. This now enables larger numbers of thermoelectric modules to be produced significantly more cost-effective. In particular, researchers use these for constructing pilot and demonstration plants with which they want to demonstrate the potential of the technology.

The new thermoelectric modules consist of so-called half-Heusler materials. They can be used in the high-temperature range up to 600 degrees Celsius. They therefore cover a temperature range that was previously unattained with the usual materials made of bismuth telluride – these can only be used up to about 250 degrees Celsius. The modules made of half-Heusler materials are suitable for generating electricity from the waste heat produced by high-temperature processes in the metals, cement and glass industries. They can also transform waste heat from cogeneration (CHP) plants or motor vehicle combustion engines into electricity.

Automation lowers manufacturing costs

The pilot production plant developed by Fraunhofer IPM provides automatic sawing, polishing, placement and soldering in the module production. This enables significantly more high-temperature thermoelectric modules to be manufactured than before. This also makes demonstrators and prototypes of complete systems considerably cheaper, as comprehensive thermoelectric systems for recovering waste heat often contain up to several hundred modules.

König explains: "Our pilot plant shows that cost-effective mass production is feasible. This brings us a lot closer to the industrial use of thermoelectric modules."

Utilisation of waste heat with thermoelectrics

Thanks to the more favourable manufacturing costs, the researchers expect that thermoelectric generators will soon make it possible to increase the power yield even with small household CHP plants or condensing boilers. The Fraunhofer researchers are planning to build suitable thermoelectric generators for CHP plants with appropriate heat exchangers. To demonstrate the potential of the technology, they want to use these to generate electricity from the waste heat on a kilowatt scale. They will achieve the desired output by connecting up to several hundred modules together.

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Development of the pilot production
Fraunhofer IPM

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thermoelektrik.info
Deutsche Thermoelektrik-Gesellschaft (DTG)

thermoelektrik.fraunhofer.de
Fraunhofer-Netzwerk Thermoelektrik

Infotip

Thermoelectrics: power from waste heat
BINE-Themeninfo I/2016