Supercapacitor Basics (Part 2):
Uses and Effects of Supercapacitors

7/28/2015
Basic

Category: Capacitor Room

1. Introduction

In Part 1, we described the structure and characteristics of Murata’s Supercapacitors (EDLCs) and noted how they compare to other types of capacitors and other devices. In Part 2, we describe the typical uses and effects of Supercapacitors and present application examples.

 

2. Typical uses

As noted in Part 1, Murata’s Supercapacitors have small and slim packages and deliver low ESR, high capacitance, and high output. They have excellent charge-discharge cycle service life characteristics and are highly reliable in comparison with electrolytic capacitors and other Supercapacitors. They are principally used in the following four applications, where it is possible to make full use of their characteristics:

(1)Peak output assist
(2)Auxiliary backup power supply
(3)Battery load reduction
(4)Storage element

We describe each of these applications, in order, below.

(1) Peak output assist
In peak output assist applications Supercapacitors are used to supplement the supply of electricity from the power supply in situations where a momentary burst of power is needed, such as when a camera’s flash unit is triggered. By using Murata’s high-output Supercapacitors, you can reduce the size of the power supply while adding high-output functionality and improving the performance of your products.


【Example applications】
LED flash units, products employing compact DC motors, gas/water smart meters, remote keyless entry (RKE) systems, etc.
 
Electrical Double-Layer Capacitor Basics (Part 2): Uses and Effects of Electrical Double-Layer Capacitors
Figure 1. Peak Output Assist


(2) Auxiliary backup power supply
An Supercapacitor can be used as a data backup power source when the main power supply is interrupted. Their long service life, lower ESR than batteries, and compact dimensions make it possible to implement high-energy, high-output backup functionality in a very limited space.


【Example applications】
Memory backup for SSDs, PLCs, etc., “last gasp” transmission capability for communication equipment 
Electrical Double-Layer Capacitor Basics (Part 2): Uses and Effects of Electrical Double-Layer Capacitors
Figure 2. Auxiliary Backup Power Supply


(3) Battery load reduction
Supercapacitors can be used to assist the battery by reducing the load in cases where the battery voltage could become unstable because the load on the battery is too large. Supercapacitors are used in this way in communication equipment and audio equipment to ensure stable operation and improve the sound quality.


【Example applications】
Audio equipment, communication equipment of various types, portable printers, security devices, healthcare devices, etc.
Electrical Double-Layer Capacitor Basics (Part 2): Uses and Effects of Electrical Double-Layer Capacitors 
Figure 3. Battery Load Reduction


(4) Storage element
Due to their low ESR, Murata’s Supercapacitors can charge and discharge reliably even when the input is unstable. This makes them suitable for use as “harvester” storage devices in cases where the amount of power generated is uneven. Also, their long service life makes it possible to build power supplies that are maintenance-free.


【Example applications】
IoT devices employing energy harvesting, power supplies for sensor network systems, etc.
 Electrical Double-Layer Capacitor Basics (Part 2): Uses and Effects of Electrical Double-Layer Capacitors
Figure 4. Storage Element

3. Typical uses and effects

(1) Example of use in an LED application
  • ・Usage example: LED flash for DSC or DVC, LED beacon for fire alarm
  • ・Effects: Contributes to improved functionality with the ability to produce a large current to illuminate the LED.
In flash applications, a camera flash unit with a long service life and compact size can be achieved through the use of an LED. Distinctive effects can be produced by varying the illumination duration and LED output, providing rapid-fire functionality, etc.


For 4A discharge using a DMF series EDLC rated at 1,000mF, a one-second discharge results in a potential difference of 5.5V to 2.5V.


 Electrical Double-Layer Capacitor Basics (Part 2): Uses and Effects of Electrical Double-Layer Capacitors

 Electrical Double-Layer Capacitor Basics (Part 2): Uses and Effects of Electrical Double-Layer Capacitors

Figure 5. LED Flash Usage Example

 

(2) Example of use in a gas or water smart meter
  • ・Usage example: Battery-driven smart gas meter or smart water meter
  • ・Effects: Using Murata’s Supercapacitors as an auxiliary power supply for communication or valve opening/closing functions can help you extend the service life of the primary power supply from 15 to 20 years. In addition, the low ESR of Murata’s Supercapacitors means that loss is low even at low temperatures, allowing efficient utilization of the energy stored in the battery.
 
 Electrical Double-Layer Capacitor Basics (Part 2): Uses and Effects of Electrical Double-Layer Capacitors

Electrical Double-Layer Capacitor Basics (Part 2): Uses and Effects of Electrical Double-Layer Capacitors 

Figure 6. Example of Use in a Smart Meter

(3) Example of use in an SSD
  • ・Usage example: Backup of SAS, SATA, or PCIe enterprise SSD
  • ・Effects: Space savings can be realized by reducing the number of tantalum capacitors or aluminum electrolytic capacitors. In terms of stored energy, an EDLC rated at 470mF is equivalent to more than 100 high-capacitance tantalum capacitors. For example, backup for approximately one second can be achieved with discharge at 10W from 5.5V to 2.0V. 
 
Electrical Double-Layer Capacitor Basics (Part 2): Uses and Effects of Electrical Double-Layer Capacitors 

 Electrical Double-Layer Capacitor Basics (Part 2): Uses and Effects of Electrical Double-Layer Capacitors  Electrical Double-Layer Capacitor Basics (Part 2): Uses and Effects of Electrical Double-Layer Capacitors

Figure 7. Example of Use for SSD Backup



(4) Example of use in a battery-driven audio device
  • ・Usage example: Power supply stabilization (sound quality improvement) for high-end portable audio device
  • ・Effects: Contributes to improved sound quality by stabilizing the power supply line.
  
Electrical Double-Layer Capacitor Basics (Part 2): Uses and Effects of Electrical Double-Layer Capacitors


 
 Electrical Double-Layer Capacitor Basics (Part 2): Uses and Effects of Electrical Double-Layer Capacitors

Figure 8. Example of Use in an Audio Amplifier




4. Conclusion

The examples above show applications that make the most of the low ESR and high capacitance of our Supercapacitors. Murata Manufacturing will continue to develop EDLC products with even lower ESR and more compact size, and that contribute to systems with increased functionality, greater compactness, and improved energy efficiency.

Portions of this document appeared in slightly different form in Section 2 of the January 29, 2015 issue of High Technology, published by Dempa Shimbun.




Department Responsible: High Performance Power Device Department, Murata Manufacturing Co., Ltd.