Supercaps get a bigger role in energy reclamation

The typical goal in applications incorporating supercaps is to substitute these devices for some of the energy capacity that would otherwise be provided by a battery. The resulting battery/supercap combo can typically take up less space (and weigh less) than an equivalent battery operating alone. Supercaps also charge up more quickly than batteries with equivalent energy storage.

By most accounts, supercap makers are trying to both advance their storage technology with such exotic methods as carbon nanotubes, and to keep down the cost of their products. Industry observers say the latter tactic will dominate the industry for the near future. Several vendors are mechanically redesigning their bread-and-butter components. The price of some large supercap systems for industrial applications has also fallen to one-tenth that of a decade ago. And though supercap technology is still considered to be in its infancy, the ultracapacitor community now has its own industry organization, KiloFarad International, Arlington, Va.

“Right now it’s all about cost reduction, not energy-density,” says Steve Minnihan, Power Analyst for energy storage at Lux Research (Boston). “There are some companies that have tried to improve energy-density, but that’s poor technological strategy. It doesn’t make economic sense, when you can just couple the cap with a battery, which has an energy density that the supercap will never be able to achieve.”

One example of an energy harversting application employ supercaps is this wireless node incorporating a Powercast P2110 Powerharvest Receive and AVX supercap.

Lux pegs the global supercapacitor market at $122M in 2008 for the consumer areas for the 20 or so companies in the business worldwide. Minnihan sees the consumer market growing to $550M by 2014. “As a full fledged commercial product, supercaps are in mid adolescence,” says Mike Sund, VP of Communications and Investor Relations for Maxwell Technology (San Diego). “The market research is tricky to get right because the supercap market isn’t reported as such in some of the bigger companies.” These include players in Japan and Korea (e.g., Panasonic, Nesscap, Nippon Chemi-Con) that mainly concentrate on their own country’s industrial applications. “A loose estimate for the overall market is about $200M,” he says, noting that Maxwell’s portion was $5M in 2004 and $44M in 2009 (of which a good part was in automotive), and may rise by 50% this year.

Power for portables

Here’s how marketing research firm Lux Research sizes up the market for ultracap applications
Select figure to enlarge.

The first battery-with-capacitor systems introduced almost a decade ago typically went into board-mounted backup applications. Devised by such companies as Tadiran (Lake Success, N.Y.), they delivered peak pulses measured in amps and a charge-discharge cycle life measured in the thousands. Tadiran’s PulsesPlus product included a lithium-based “hybrid layer capacitor” (a supercapacitor, although not so named), which had an equivalent series resistance (ESR) of a few hundred milliohms.

In contrast, today’s supercap products are more typically called on for a burst of energy that lets a BlackBerry send email or a smart utility meter transmit a few packets of data. Their life cycle has risen at least one hundredfold and their ESR has been cut by a factor of between 10 and 100. “Today you can generally get a half-million cycles of charge/discharge before you see noteworthy degradation,” says Steve Minnihan. “With the rate at which consumers are upgrading their cell phones and cameras, the supercap will not break down before the cell phone does.”

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