Analysis of the terminal effect on the resistance tape at its constant and variable local conductivity

The regularities of current distribution in a rectangular electrochemical cell with equipotential anode and resistance tape cathode were studied by means of mathematical and physical modeling. For the case of uniform resistance tape and linear cathode polarization, the criteria of electric field similarity on the tape were obtained and the effect of different parameters was studied. A good quantitative agreement between the calculated and experimental profiles of current distribution along the tape was obtained. It was shown that a decrease in ohmic loss and corresponding weakening of the terminal effect are promoted not only by an increase in average conductivity κt,av but also by the variable profile of the local tape conductivity κt(x) increasing to the current lead. Different shapes of increasing κt(x) profiles were considered. For the linear κt(x) profiles increasing and decreasing to the current lead, with the equal average tape conductivities, it was shown theoretically and confirmed experimentally that linear κt(x) profile increasing to the current lead noticeably improves the uniformity of current distribution over the tape in comparison with κt,av, while a similar but reverse (decreasing to the current lead) κt(x) profile sharply enhances the terminal effect.