Device optimization and large-scale roll-to-roll manufacturability of flexible thin-film thermoelectric generators

Journal article

The optimization of flexible thin-film thermoelectric generators (TEGs) suitable for large-area roll-to-roll (R2R) processing is investigated. The selection of suitable contact materials, in-line patterning of connections, and dimension of the thermoelectric (TE) strip are studied. As a result, copper is selected for contacts because it possesses a similar performance to gold while being cheaper. Both in-series- and in-parallel-connected devices are found to work well and provide a voltage-dominant and current-dominant power source, respectively. The Seebeck coefficient and internal resistance of a device are extracted from the fit line to the measured power data. The in-parallel-connected TEG has a much smaller internal resistance and is thus suitable for wearable/portable devices with a small load resistance. A shorter and wider TE strip generates more power. To the authors’ knowledge, this is the first study that experimentally proves a downward trend of power output with increasing strip length. In addition, an industrially feasible/continuous process is proposed for large-scale manufacture of flexible TEGs, by R2R sputtering TE materials on polymer webs, inkjet printing contacts, and segmenting using a laser. A segmented configuration is able to relieve internal strains in the device, while subjected to bending (e.g., within a wristband) to retain performance.

Authors: Tao, X; Zhang, K; Gregory, D; Liu, J; Assender, H

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Wiley
• Journal: Energy Technology
• Volume: 9
• Issue: 9
• Article number: 2001008
• Publication date: 2021-07-18
• Acceptance date: 2021-06-21
• DOI: 10.1002/ente.202001008
• EISSN: 2194-4296
• ISSN: 2194-4288
• Language: English
• Keywords: FFR