Electrical contacts resistance determination in thermoelectric modules by the method of varying the height of thermoelectric elements by operation

Аuthors

Vorobyov D. V.^*, D.

Moscow Power Engineering Institute (National Research University), 14, Krasnokazarmennaja St., Moscow, 111250, Russia

*e-mail: vorobyevdv@mpei.ru

Abstract

This paper presents the results of an experimental study of electrical contact resistance of the contact of thermoelectric element- contact pad in thermoelectric modules (TEM) according to operational parameters. This method includes double approximation to exclude the impact of Joule heating and parasitic thermal EMF during measurements. A finite element model of TEM was designed in COMSOL Multiphysics software that includes temperature dependences of thermoelectric properties of materials. Electrical resistance of the pads and measured contact resistance of thermoelectric element – pad. Experimental verification was performed to prove the need of accounting of electrical contact resistance in TEM model. 
In the first part of the study the analysis of electrical contact methods is presented. All the methods can be divided in two groups: local measurement methods and methods of analysis of full TEMs. Method presented in current article belongs to the second group but with determination of electrical contacts resistance under operation.  
In the second part of the study the methodology and experimental results of electrical contact resistance are presented. Since electrical contact resistance does not depend on thermoelectric elements length, the method of measuring of TEMs performance and approximation is suggested. Obtained results show that electrical contact resistance is in appropriate range and equal to 5,2×10⁻¹¹ Ohm×m². 
Determined value of electrical contact resistance was implemented in COMSOL Multiphysics 3D model to verify experimental TEM performance. 
Further, developed 3D model was used to compare TEM performance under different operational modes. This study was compared to the model that does not include electrical contact resistance. The results show that electrical contact resistance should be considered to predict TEM performance with higher accuracy especially in TEM systems with big quantity of electric contacts. 

Keywords:

Peltier element, thermoelectric module, thermoelectric cooler, contact resistance, COMSOL

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