Comparison of supercapacitors, common capacitors and batteries

Voltage

The supercapacitor has a recommended operating voltage or optimum operating voltage, which is determined based on the maximum operating time of the capacitor at the highest set temperature. If the applied voltage is higher than the recommended voltage, the life of the capacitor will be shortened. If the overvoltage is over a long period of time, the electrolyte inside the capacitor will decompose to form a gas. When the pressure of the gas is gradually increased, the safety hole of the capacitor will be broken or broken. . A short overvoltage is tolerable for the capacitor.

Polarity

Supercapacitors are designed with symmetrical electrodes, that is, they have a similar structure. When the capacitor is first assembled, each electrode can be regarded as a positive or negative pole. Once the capacitor is 100% fully charged for the first time, the capacitor becomes polar. Each supercapacitor has a housing on the outer casing. The sign or logo of the negative pole. Although they can be shorted to reduce the voltage to zero volts, the electrode still retains a small fraction of the charge, which is not recommended. The longer the capacitors are charged in one direction, the stronger their polarity becomes. If a capacitor is charged in one direction for a long time to change polarity, the life of the capacitor will be shortened.

Ambient Temperature

The normal operating temperature of supercapacitors is -40 °C ~ 70 °C, the combination of temperature and voltage is an important factor affecting the life of supercapacitors. Under normal circumstances, for every 10 °C increase in temperature, the life of the capacitor will be reduced by 30% to 50%. In other words, if possible, the temperature of the supercapacitor can be lowered to reduce the capacitance. Attenuation and internal resistance increase, if it is impossible to reduce the use temperature, then the voltage can be lowered to offset the negative impact of high temperature on the capacitor. For example, if the operating voltage of the capacitor is reduced to 1.8V, the capacitor can operate at a high temperature of 65 °C. If the supercapacitor is used below room temperature, the supercapacitor can be operated above the specified voltage without accelerating the degradation inside the supercapacitor and affecting the life of the supercapacitor, increasing the operating voltage of the supercapacitor at low temperatures. It can effectively offset the increase of internal resistance of super capacitor at low temperature. At high temperatures, the internal resistance of the capacitor will increase. This change is permanent and irreversible (the electrolyte has been decomposed). At low temperatures, the increase in internal resistance of the capacitor is a temporary phenomenon because the electrolyte is sticky at low temperatures. Increased enthalpy reduces the speed of movement of ions.