I love batteries. One of the first engineering toys I enjoyed when I was a youngster back in the early 1950s was a dc motor that my father and I built from a kit. A pair of series-connected D cells powered the motor. It was quite a treat when my dad gave me two shiny new Burgess D cells when the old ones wouldn’t turn the armature anymore. Today, I still get the same satisfying sense of renewal whenever I pop new AAA cells into my camera or PDA.
I’m not the only one who goes ape over batteries. Battery technology garners lots of attention in this era of portability and mobile electronics. Exploding Sony laptop batteries aside, you have to marvel as auto makers make the leap from nickel-metal-hydride batteries, as used in today's hybrid automobiles, to much higher-capacity lithium-ion chemistries, as used in battery packs for the proposed Chevrolet Volt and Chrysler ENVI.
Micro Power SourcesAlthough high-powered applications are stealing the battery limelight, there are intriguing developments at the opposite end of the power spectrum. One of the most interesting is the advent of flexible paper-thin batteries. These micro power sources are finding homes in many unique products. Folks are designing them into non-passive RFID tags, consumer smart cards, electronic shelf labels, medical diagnostic products, powered drug delivery dermal patches, remote sensors, and so-called smart UPS and FedEx packages, to name just a few leading edge applications.
Until now, most of these products were powered by coin cells, which are reasonably bulky, especially compared to the size of the circuits they power. There is an embryonic industry movement, however, to displace coin cells with thin-film batteries based on inorganic electrolytes. If recent developments are any indication, gird your loins. According to researchers at
NanoMarkets, thin-film batteries could become a $2 billion a year market in the near future.
Printed ElectronicsThe NanoMarkets findings are in lockstep with the trend to produce printed electronics. Analysts at IDTechEx, studying printed electronics and nano-technologies, say the worldwide market for printed and thin-film electronics may grow to as much $5 billion by 2011, possibly expanding to a whopping $48 billion by 2017.
So, while the overall worldwide economy stagnates, there are forward-looking organizations poised to exploit this nascent potential (no pun intended). One is Ohio-based
Blue Spark Technologies. The company's printed batteries use intellectual property acquired from Energizer (formerly Eveready Battery).
Launched in 2003 as Thin Battery Technologies, Blue Spark's objective was to develop thin flexible printed batteries, and it has succeeded in its quest. Since 2004, over 300,000 thin printed batteries have been produced and delivered.
Blue Spark's ST Series printed batteries are based on ubiquitous 1.5 V zinc-carbon chemistries. These batteries are the highest energy density offerings in the company's growing product line, with the ability to deliver up to a milliampere of peak current. What's more, voltages higher than 1.5 V can be achieved with series cells, all in one package. ST Series batteries are thinner than coin cells and meet RoHS (Restrictions on Hazardous Substances) standards.
Blue Spark's UT Series are claimed to be the industry's thinnest printed flexible batteries, with Z-height profiles as low as 0.020 inch, but given the pace of competing technologies, that coveted position on the totem pole may not last. Regardless, UT Series batteries can be fabricated in almost any shape or size. Typical form-factor UT batteries are capable of delivering approximately 12 mA-hr of energy at 1.5 V, with peak drain currents of at least a milliamp.
The company also offers a high-drain product, dubbed the HD Series. It's for applications requiring a boost during peak current delivery, such as loudspeaker equipped greeting cards. In these kinds of applications peak current delivery can be greater than 5 mA. Like their UT counterparts, HD Series batteries can also be custom shaped to fit almost any form-factor.
The Printed Functionalities DepartmentIn Europe, the
Fraunhofer Research Institution for Elektronic Nano Systems, ENAS, is also working on micro/nano batteries and flexible printed batteries. The Printed Functionalities department at ENAS is partnering with the Digital Printing Group of Chemnitz University of Technology in this thrust.
Significantly, ENAS' serial connections between cells are printed in one step. That achievement results in batteries with output voltage as multiples of 1.5 V. So far, 3 V, 4.5 V, and 6 V batteries have been demonstrated, based on zinc-manganese chemistries with 2 mA-hr/cm
2 capacities. These batteries are less than 0.024-in. thick. By using high efficiency printing technologies and materials, yields in high-volume manufacturing are projected to exceed 90%.
In Israel,
Power Paper is also working on flexible batteries. Power Paper's process prints its batteries on polymer film substrates by means of a simple mass-printing techniques. Zinc-manganese layers are fabricated from proprietary ink-like materials.
Most impressively, every layer of Power Paper's batteries (current collectors, cathodes, electrolytes, anodes, adhesive sealing frames, and separators) is screen-printed, and can be printed on to an almost limitless variety of film substrates; the batteries can exhibit the same elasticity and flexibility as the paper or plastic surface they're printed on. They can also be shaped to fit the size, thickness, and form-factors required by a given end product. It’s really quite amazing.
Letting no grass grow under its feet, Power Paper is shipping next-generation printable microelectronic devices, and recently inked an accord with Motorola to license the latter's technology in an RF identification smart label system. Power Paper's printable micro-power source will power Moto's low-cost printable RFID label.
Keep an eye peeled for these products, and others like them. While they may not have the pizzazz of the giant battery packs set to debut in the ENVI and Volt, they're bound to impact the development and deployment of a great variety of nomadic products.
Your comments are welcome. Please write me at
amm at en-genius dot net, or post your thoughts and observations on our blog.
