For the selection of supercapacitors, power requirements, discharge time and system voltage changes play a decisive role. The output voltage drop of the supercapacitor consists of two parts, one part is the release energy of the supercapacitor; the other part is caused by the internal resistance of the supercapacitor. Which of the two parts is dominant depends on the time. In very fast pulses, the internal resistance part is dominant, while in long-duration discharge, the capacitive part is dominant.

parameter selection

The following basic parameters of Farad capacitors determine the size of the selected capacitor:

Supercapacitor module. Working voltage; Working cut-off voltage; Average discharge current; How long is the discharge time.

Compared with batteries, supercapacitors have the following characteristics:

Super longevity, charging and discharging more than 500,000 times, which is 500 times that of Li-Ion batteries and 1,000 times that of Ni-MH and Ni-Cd batteries. If the super capacitor is charged and discharged 20 times a day, it can be used continuously for 68 years.

It can be charged with high current, the charging and discharging time is short, the charging circuit is simple, and there is no memory effect.

Ultra-low series equivalent resistance (LOW ESR), power density (Power Density) is dozens of times that of lithium-ion batteries, suitable for high-current discharge (a 4.7F capacitor can release more than 18A instantaneous current).

Maintenance free and sealable.

The temperature range is -40°C to +70°C, and the general battery is -20°C to 60°C.

Supercapacitors can be formed in series and parallel to form a supercapacitor module, which can withstand voltage and store higher capacity.

Farad capacitor selection method:

Supercapacitors are different from batteries and may be superior to batteries in some applications. Supercapacitor manufacturers sometimes combine the two, and combining the power characteristics of capacitors with the high energy storage of batteries is a better approach.

Supercapacitors can be charged to any potential within their rated voltage range and fully discharged. The supercapacitor module battery is limited by its own chemical reaction to operate in a narrower voltage range, and may be damaged if overdischarged.

Supercapacitors can repeatedly transmit pulses of energy without any adverse effects, whereas batteries have a significantly reduced lifespan if they repeatedly transmit high-power pulses.

Supercapacitors can charge quickly and batteries can be compromised when they charge quickly.

Supercapacitors can be repeatedly cycled hundreds of thousands of times, while battery life is only a few hundred cycles.

The state of charge (SOC) of a supercapacitor is a simple function of voltage, while the state of charge of a battery involves a variety of complex conversions.

Supercapacitors can store more energy than their modestly sized conventional capacitors, and batteries can store more energy than their modestly sized supercapacitors. In some applications where power determines the size of energy storage devices, supercapacitors are a better approach.