Charging at Constant Cell Current

Equation (2.41) shows that when f = 0, V = IceuResr when t = °° (the moment when the supercapacitor is fully charged), V = IceiiResr + Iceu - this case, the voltage across the supercapacitor VJ reaches its maximum value, defined as, which is equal to. sRp- If there is no leakage current, °° and Equation (2.41) can be simplified to  

Equivalent charging circuits of supercapacitor at constant voltage (a) and at constant current (b). 

Using Equation (2.42), the time (t required to charge a supercapacitor to a targeted voltage level of Vj can be obtained when 

Equation (2.42) suggests that the cell voltage has a linear relationship with charging time. Note that Equation (2.42) can be used to describe the circuit shown in Eigure 2.13. If the ESR does not exist (R g. — 0), the cell voltage will 

If charging an ideal supercapacitor (R = 0, and R = °°) using a constant current, the cell voltage will become  

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