Analysis on Properties of Thermoelectric Composite by Finite Element Method

The addition of metal into thermoelectric materials has been used as one method to improve thermoelectric performance. Although the electrical resistivity of thermoelectric materials can be decreased largely by the metal composition, it is always accompanied with some negative effects such as the thermal conductivity increase. Therefore, it seems necessary to investigate the composite effects and their influence on thermoelectric properties. In the present work, analysis models of finite element method with series and random distribution for thermoelectric composites were proposed and established. Thermoelectric properties including electrical resistivity, Seebeck coefficient and thermal conductivity of thermoelectric composites were investigated by the proposed models. Thermoelectric properties calculated by the models were compared with those obtained by the experiments and theories of the rule of mixture and the general effective medium equation (GEM). The results revealed that the values of thermoelectric properties calculated from the proposed models were consistent with those from the experiments and the rule of mixture in the series model. In addition, the results calculated by the random distribution model showed a similar tendency with those from the experiments and GEM. The proposed analysis models are suitable to discuss the thermoelectric properties of thermoelectric composites.