Backup power battle, super capacitor or battery

Many systems require backup power, and the question is: What are the options for storage media for such backup power supplies? The traditional choice is capacitors and batteries.

It can be said that capacitive technology has played an important role in power transmission and distribution applications for decades. For example, traditional thin film and oil-based capacitors are designed to perform a variety of functions, including power factor correction and voltage balancing. However, a great deal of research and development has taken place over the past decade, resulting in significant improvements in capacitor design and capacity. These advanced capacitors are called supercapacitors and are ideal for battery energy storage and backup power systems. Supercapacitors have a limited total energy storage, but their energy density is very high. In addition, supercapacitors have the ability to quickly release high energy and charge quickly.

Supercapacitors are not only compact, but also robust and reliable to meet the requirements of a backup power system for short-term power loss events. In addition, supercapacitors are easily stacked in parallel or in series, even in a series-parallel combination to provide the necessary voltage and current for the final application. However, supercapacitors are not just capacitors with very large capacitance values. Supercapacitors of the same size and weight have higher energy density and greater capacitance than standard ceramic, tantalum or electrolytic capacitors. While supercapacitors require special maintenance, they can even replace batteries in data storage applications that require high current/short-time backup power.

In addition, supercapacitors can be used in a variety of high peak power and portable applications that require high burst currents or short battery backups, such as UPS systems. Compared to batteries, supercapacitors provide higher burst-peak power in smaller sizes, with more charge cycles and a wider operating temperature range. By reducing the upper cut-off voltage of the supercapacitor and avoiding high temperatures (> 50 °C), the life of the supercapacitor can be maximized.

On the other hand, batteries can store a lot of energy, but they have limitations in terms of power density and delivery. There is a chemical reaction inside the battery, so the number of charging cycles is very limited. Therefore, if you want to deliver the right amount of power for a long time, then the battery is most effective, and letting the battery output a large current very quickly will seriously shorten its effective service life.