Thermoelectric Diffusion Potential and Thermoelectric Energy

At present, the advancement of thermoelectric technology remains largely focused on developing high-performance thermoelectric materials, while comparatively little attention is directed towards its fundamental principles. To address this gap, this study introduces a new physical quantity, the “thermoelectric diffusion potential”, which clarifies the physical interpretations of various thermoelectric coefficients. Analyses reveal that, within a thermoelectric element, the Seebeck coefficient represents a balance between the thermoelectric diffusion field and electrostatic field, rather than between temperature and voltage differences. Using the thermoelectric diffusion potential, the relationship between the Seebeck and Peltier coefficients can be derived directly. Building on this framework, two additional physical quantities, namely the “thermoelectric energy” and “thermoelectric energy flow”, associated with the thermoelectric diffusion potential, are introduced. The formulation of thermoelectric energy flow helps derive the energy conversion relationship at the interface on a macroscopic level. Specifically, energy conversion at the interface occurs between thermoelectric and thermal energy flows, while within the element, it takes place between thermoelectric and electrical energy flows. Owing to the dual nature of internal energy in thermoelectric materials, manifesting as both thermal and electrical energy, the conversion within the element can also be regarded as one between thermal and electrical energy flows. The proposed quantities constitute an important complementary interpretation for the existing thermoelectric framework.