Influence of difference in dice properties on figure of merit of thermoelectric cooler

The influence of differences both in thermoelectric and dimensional parameters of dice on the work of a thermoelectric cooler is investigated. It is shown that its work is described by the same equation as that for one die, with Seebeck coefficient, resistance and thermoconductance being replaced by average values. The analysis of the received equations is presented. It is shown that the distribution of dice properties may not diminish the figure of merit if thermoelectric materials in use are of high quality and the thermoconductivity of the ceramics is high. The rule to estimate the influence of dice distribution on the work of the thermoelectric cooler is proposed and it consists in small difference between the average dice resistance and the inverse value of dice conductivity. In practice the difference of the value of electroconductivity of dice ±150 1/Ω cm is irrelevant for the work of the module. Besides, the influence of doping near the electrical contacts is analysed. It is shown that this can be used for the increase of figure of merit of the module