Polarization Curve and Voltage Losses

When the fuel cell operates, the actual voltage of the cell is less than the value of the OCV. Cell voltage is the actual voltage of the fuel cell and the current density, i, is the cell current, 1, per cell active area, A.  

The cell current is equal to the stack current because the stack is formed by connecting the individual cells in series. 

Polarization curves provide information on the performance of the cell or stack as a whole. While they are useful indicators of overall performance under specific operating conditions, they fail to produce much information about the performance of individual components within the cell. They cannot be obtained during normal operation of a fuel cell and take significant time. In addition, they fail to 

The output voltage of a single cell,, can be defined as follows  

Activation overvoltage or activation loss is caused by activation polarization, which arises from the need to move electrons and to break and form chemical bonds in both the anode and the cathode. 

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