Application of WIMA Double-Layer Capacitors

Advantages in Comparison with other Energy Storage Solutions

In general SuperCaps are used for voltage support, for fast supply of electrical energy, e.g. to cover the requirements of peak power demand, or for the saving of batteries, which as a result can be made smaller as the capacitor reduces the peak current.The typical application is the quick supply of several 100 A to 1000 A in the direct current field. The SuperCap combines the advantage of conventional capacitors as fast suppliers of electricity with that of batteries as notable energy reservoirs. Contrary to energy storage by batteries, the charging voltage represents the energy content thus a sudden voltage collapse of the SuperCap is avoided. Other benefits versus conventional batteries and rechargeable battery solutions include maintenancefree operation and a comparatively low weight, thus usage in isolated systems, e.g. inaccessible areas, is unproblematic above all since SuperCaps are resistant to temperature changes, too. When properly treated WIMA SuperCaps have a service life beyond 10 years and can easily sustain more than 500.000 charge/ discharge cycles. The efficiency is far higher than 90 %. Compared to other storage media, complete discharge of the SuperCap does not present a risk of damage.

Application Examples of Double-Layer Capacitors

In large-scale wind turbine systems, slip controllers are used to control the rotation speed by altering the angle of the rotor blades. The drives are mains-independent and if electrically controlled use the energy stored in batteries or double-layer capacitors. Due to the considerable temperature variation in the wind tower top housing, these storage devices have to meet stringent requirements. SuperCaps can help to increase profitability by remarkably reducing maintenance work.

When starting a micro-turbine or for bridging during start of a fuel cell working as UPS, generally a few 100 kJ of electrical energy are required for a system start time of approx. 10 to 20 sec. Because of their significant maintenance, service life and weight benefits, double-layer capacitors are more frequently replacing customary starter batteries.

SuperCap modules can also be used for energy storage in photovoltaic systems, hence serving as long-term "power units". Here, the capacitors can supply periodic power with higher current levels than supplied by photocells. The energy drawn is then recharged within a specific time using solar irradiation.

The recuperation of braking energy, such as in the automotive sector, is a real challenge in times of increasingly scarce resources. A vast amount of kinetic energy is generally wasted when braking. Very high energy is generated momentarily which can be stored by SuperCap modules. This energy can be made available again when required.

Well-known WIMA Quality

The WIMA double-layer capacitor is ideally suited for a vast variety of applications. Its capacitance drift over lifetime guarantees its electrical function being maintained for decades. Studies show that the WIMA SuperCap always renders its service reliably even under hardest conditions. Constant quality assessment of the capacitors is our obligation. Hence each individual WIMA SuperCap is tested according to the recommendations of the draft specifications DIN IEC 62391-1 and -2 for “Fixed Electric Double-Layer Capacitors”.