Fabrication and properties of four-leg oxide thermoelectric modules

Abstract

Four-leg oxide thermoelectric modules consisting of two pairs of p type Ca3Co4O9 and n type Ca0.95Sm0.05MnO3 bulks of 4 × 4 mm2 cross-section and 5 and 10 mm heights were constructed and their performance discussed. The modules were assembled using silver paste wherein the thermoelectric elements are electrically connected in series by silver strips and placed between alumina plates that are in parallel thermally. The performance was evaluated up to a maximum temperature of 1000 K with thermal differences of up to 925 K between the hot and cold plates. An open circuit voltage of 400 mV was generated at an operating temperature of 1000 K with a temperature difference of 925 K and internal resistance of 1.27 Ω in the case of long legs module. A maximum output power of 31.5 mW was obtained and the power decreased to 24.5 mW in a module where the height of the thermoelectric elements is halved. The quality of the modules is discussed by introducing a manufacturing factor representing the cumulative influence of various factors of the fabrication process.

Electron transport in CaMnO3 − δ at elevated temperatures: a mobility analysis

“…The electrondoped derivatives Ca 1−x R x MnO 3−δ , where R is a rare earth metal, are stable in different atmospheres and exhibit rather large values of conductivity (σ) and negative thermopower (S) up to 1000°C. These properties are of particular importance in thermoelectric devices for conversion of heat in electricity [7][8][9][10][11][12][13]. The substantially high electron conductivity, significant electrocatalytic activity, and moderate thermal expansion of Ca 1−x R x MnO 3−δ make it possible to use these materials as cathodes of solid oxide fuel cells (SOFCs) and other electrochemical devices operating at elevated temperatures [14,15].…”

Thermoelectric oxide modules tested in a solar cavity-receiver

“…In contrast to conventional TE materials based on Bi 2 Te 3 , which are toxic and have limited chemical stability above T ;523 K in air, they are temperature-stable, oxidation-resistant, and nontoxic. [1][2][3][4] Oxide materials, especially with perovskitetype structure, can be easily synthesized with controllable composition and TE properties. [5][6][7][8] The low costs of these materials are beneficial as well.…”

Thermoelectric Ca3Co4O9 ceramics consolidated by Spark Plasma sintering

“…Since the discovery of the thermoelectricity (TE) in the NaCo 2 O 4 phase [1], intensive research has been devoted to discover new oxide materials [2][3][4][5][6][7][8][9], in order to improve potential TE properties [5,[9][10][11][12] and/or to develop TE modules for power generation [13][14][15][16].…”