New Hybrid Capacitor Increases Energy Density by 115 Percent
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HYBRID CAPACITORS, developed by Ioxus, are similar to lithium-ion batteries, but they retain a far superior cycle life with more than 20,000 charge/discharge cycles possible rather than the hundreds or few thousand delivered by batteries. These capacitors store charge at the surface of the electrodes instead of within the electrodes as batteries do. Hybrid capacitors store 85 to 115% more energy than a conventional ultracapacitor, while retaining a higher cycle life than a battery. Hybrid capacitors have more power than lithium ion batteries, but less energy storage.
These hybrid components offer other advantages over standard ultracapacitors, which have an energy density of 12.8 Wh/L. The hybrid capacitor offers an enhanced capability of energy storage, providing power to applications more quickly and efficiently. Ioxus hybrid capacitors (Fig. 1.) can be charged from 1.0 VDC up to 2.3 VDC. These hybrid cells offer a maximum power of up to 5kW/kg, compared with up to 3kW/kg for “power batteries.”
Ioxus' hybrid capacitor offers benefits because of its operating temperature range of -25°C to +60°C. At the low end of the temperature range, the hybrid capacitor loses only 5% of its energy while comparable battery energy loss would by 50% or more. These hybrid ultracapacitors are 90 to 95% efficient compared with batteries that are approximately 70% efficient.
A federal appropriation earlier this year enabled the company to work with Binghamton University to increase EDLC energy density. The company began developing hybrid cells capable of storing significantly more energy than traditional EDLCs. As a result, its hybrid ultracapacitor supports the high cycle, wide temperature range and high power demands of applications like automotive subsystems, memory back-up, LED lighting and other consumer-focused markets.
For automotive applications, these hybrid capacitors can be used for short-term back-up power for memory and power windows. When disconnecting the battery, the computer loses power. If a hybrid capacitor is used, the computer will retain its power. This can be performed many times due to the high cycle life of the hybrid capacitor. For power windows or door locks, in the event of an emergency, the hybrid capacitor can provide power to unlock the doors or lower the windows when the rest of the electrical system has been compromised.
Ioxus hybrid-capacitors can be recharged as quickly as they can be discharged, allowing a rapid charge to support a high power demand. In hybrid capacitors, you can charge with up to 8A, depending on cell size.
Hybrid capacitors can be used for several applications, including:
- Flashlights
- LED applications
- Memory Back-up
- Portable Hand Tools
- Solar Charge applications
- Off-grid lighting
- Automotive subsystems such as power windows and door locks
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FEATURES
- High energy density
- High power density
- Low internal resistance (ESR)
- 10 year life
- High cycle life (+20K cycles)
- RoHS compliant
TYPICAL APPLICATION
Among the many applications for this EDLC technology is powering LED devices, which are much more energy efficient than their incandescent predecessors. For example, the hybrid capacitor can benefit new LED-based flashlights, which are brighter, lasts much longer and consumes less than one-third the power and energy of comparable halogen products.
Device manufacturers can now design hybrid capacitors permanently into these flashlights because capacitor cycle life generally matches or exceeds device life. Besides no longer needing to replace batteries, users can quickly recharge devices before use, unlike battery-operated products that usually take hours to recharge. Compared with a nickel cadmium or lithium-ion battery, hybrid capacitors provide more than 20 times the cycle life and 60 times faster recharge rates. Fig. 2 shows an LED flashlight driven by a hybrid EDLC. An initial charge on the hybrid EDLC allows it to power the LED for many minutes. The table shows specifications for the hybrid capacitors.
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