Supercapacitors are seen as an eco-friendly alternative to the sealed lead-acid (SLA) batteries most commonly used in uninterruptible power supplies.
SLA cells dominate the UPS market but do come with several drawbacks including a relatively short lifespan and susceptibility to unexpected failure.
As their costs become less prohibitive, supercapacitors are increasingly seen as a viable solution, in particular for applications that require short-term standby power (i.e. up to 30 seconds) before a transition to other backup sources like a generator.
What’s The Difference Between A Supercapacitor And A “Standard” Capacitor?
Supercapacitors work in broadly the same way as conventional capacitors do, but there are two fundamental differences.
Firstly, their plates cover a much larger surface as the metal is coated with a porous substance like activated carbon. This means they can store much more charge.
Secondly, the distance between the plates is smaller as the separator works differently. So when a supercapacitor’s plates are charged, an opposite charge forms either side of the separator, creating an electric double-layer. This layer can be as little as one molecule thick – in comparison, the thickness of a standard capacitor ranges from a few microns to a millimetre.
The thinner the separator, the greater amount of charge. While the bigger the surface area, the higher the capacitance. In practice, a supercapacitor has a much higher power density and can store as much as 10,000 times more energy per unit.
Advantages Of Using Supercapacitors
- Higher power density
- Longer lifespan
- Reduced maintenance costs
- Wide operating temperature range
- No toxic or flammable components
Disadvantages Of Using Supercapacitors
- Lower energy density
- Higher upfront costs
UPS Applications Using Supercapacitors
Due to the combination of high power density and rapid charge/discharge, SuperCaps UPS are suitable for settings prone to short-duration power peaks or disruptions that last for just a few cycles.
Their higher tolerance to ambient temperature fluctuations also makes them a viable solution in harsh environments where high temperatures are unavoidable.
In addition, supercapacitors are also suitable for:
- Renewable energy installations
- Hospital diagnostic equipment
- Regenerative braking on trains