Consider an eCall system, which is becoming more pervasive in newer cars across the globe. It’s a pretty simple bit of technology: in the event of a collision in which a car’s airbags are deployed, the eCall system automatically contacts emergency services. It uses GPS to relay the time, your location, what type of car you’re in, and what kind of fuel it uses to the authorities, while a microphone in the car allows you to speak directly to call handlers when the system is activated. These eCall system can share what direction you were travelling in when the incident occurred, allowing authorities to know which side of the freeway they need to head to in the event of a collision. All this allows ambulance, police, and fire crews to reach you as quickly as they can following an accident, armed with as much information as possible. An individual can also activate eCall by pressing a button, so if someone becomes ill (or has been injured in a collision in which the airbags haven’t deployed), help can still be easily summoned.
Having acknowledged the need for backup power in a wide array of systems, the question then arises: what are the options for storage mediums for this type of backup power? Traditionally, the choices have been capacitors and batteries.
It is fair to say that capacitor technology has played a major role in power transmission and delivery applications for multiple decades. However, in the past decade, substantial research and development has led to significant advances in capacitor design and capabilities. These advanced capacitors or supercapacitors (also known as ultracapacitors) are ideal for use in battery energy storage and backup power systems. They may be limited in terms of their total energy storage; nevertheless, they are energy dense. Furthermore, they possess the ability to discharge high levels of energy quickly and recharge rapidly.
Supercapacitors are not only compact, but they are robust and reliable, and they can support the requirements of a backup system for short-term power-loss events such as the ones already outlined herein. They can easily be paralleled or stacked in series or even a combination of both to deliver the necessary voltage and current demand by the end application. Compared to standard ceramic, tantalum, or electrolytic capacitors, supercapacitors offer higher energy density and higher capacitance in a similar form factor and weight, so they are also finding use in a variety of high peak power and portable applications in need of high current bursts or momentary battery backup, such as UPS systems.