Module Geometry and Contact Resistance of Thermoelectric Generators Analyzed by Multiphysics Simulation

Abstract

Thermoelectric device performance is determined by not only the properties of the thermoelectric material but also the geometrical design and thermal matching of the materials. Leg length and contact quality strongly influence thermoelectric generator efficiency. Experimental results for contact properties are compared with the latest performance measurements on modules manufactured from Bi 2 Te 3 compounds. Module performance is related to the obtained contact resistance and thermoelectric material properties. The different influences are studied using thermoelectric multiphysics finite-element modeling of examples where, in addition to the thermoelectric field equations, further effects such as convection and radiation as well as the temperature dependency of the material properties are taken into account. Extensive thermoelectric device modeling is used to understand the experimental findings with respect to contact properties and geometry.

Material Optimization for a High Power Thermoelectric Generator in Wearable Applications

“…The copper pad in the device is used as an interconnection between the thermoelectric materials, and when the copper pad is too thin, it degrades the ZT of the device [16]. As shown in Figure 6, when the copper is thickened, the copper resistance decreases and the power density of the device increases slightly.…”

“…As shown in the Equation (1), generated power from the device is increased with Z dev T for constant input heat flux. In the practical situation, the Z dev T changes depending on the contact resistance in the device [16], the thermal parasitic resistance [17], etc. All of these factors, however, are negligible in the ideal case and the material ZT is a more dominant factor that affects Z dev T. If the condition is ideal and the N and P type of thermoelectric leg (TE leg) have the same properties, Z dev T is exactly the same as material ZT [14].…”

Modeling of a Thermoelectric Generator Device

“…One thing to note is that the efficiency of TEG is still low compared to other energy-conversion techniques. A lot of effort has been made to enhance efficiency [13,14]. Given that heat sources are plenty and free, TEGs could be promising solutions, when they are employed to harvest waste heat from industry activities and central-heating systems.…”

Maximum Power Point Controller for Thermoelectric Generators to Support a Vehicle Power Supply

“…The Seebeck-effect causes a TEG to generate electrical power when a temperature gradient is applied. The maximum power of a TEG depends on the material characteristics of the semiconductors in the TEG as well as the geometric parameters of the couples [3,5]. These parameters and materials can be selected in relation to various optimization criteria.…”

“…These parameters and materials can be selected in relation to various optimization criteria. This includes the temperature range of materials, the desired electrical rated power and the back pressure of the ICE [1,4,5,6]. This implies that TEGs must be designed and optimized for individual applications.…”