The relationship between current efficiency and cell voltage in ion membrane electrolyzers
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It is known that an increase in cell voltage leads to a decrease in the current efficiency of the electrolyzer, but why does this occur? Are there any specific calculation formulas for current efficiency related to slot voltage? Thank you.
The increase in slot voltage and the decrease in current efficiency are not absolute, as there are many reasons for them to affect each other.
It’s similar to the performance curve of a pump
What actually affects current efficiency is the actual output, and many of the factors that influence this actual output tend to cause an increase in cell voltage. Since cell voltage is the easiest to measure and observe, it is generally used as an indicator; being a result, it cannot be included in formulas.
There is no absolute necessity for an increase in slot pressure to correspond to a decrease in current efficiency. From the perspective of the single-cell slot, the current efficiency decreases, which is reflected in the slot voltage, which may either increase or decrease. If the pinhole pressure of the ion membrane is reduced, the current efficiency decreases. The increase in cell voltage after overall operation, along with a decrease in current efficiency, is mainly due to the following reasons: 1. The quality of the brine – impurity ions accumulate on the ion exchange membrane over time as a result of prolonged operation. 2. Degradation of ion exchange membranes caused by the deposition and crystallization of impurity ions, high temperatures, bubbles, etc. 3. Consumption of the electrode coating. A reduction in power consumption can be simply understood as more electricity being used for other purposes, such as generating heat. It was not used in the production of the product.