Printed Batteries Help Enable Smart Shipping Labels
Published: September 29, 2011 Category: Emerging Electronics

Emerging technology markets are difficult to forecast in part because new applications often depend on several component innovations. Each of these technologies evolves independently, but the application cannot emerge until all of the components are sufficiently mature.

Smart labels for shipping and logistics are such an application. They incorporate RFID tags, sensors, and batteries. For cost reasons, the ideal smart label would use printing technology for all three components. Yet printed electronics are just beginning to become commercially important, and as a result the technology needed to support smart labels is only starting to emerge.

The first element, the RFID tag, is probably the most mature. In its most basic form, an RFID tag is simply a remotely readable memory. It stores anywhere from a few bits to several megabytes, depending on the tag, and draws the current it needs via induction, from an RF coil in a reader device. While it’s generally agreed that future supply chains will depend on RFIDs to track everything from work-in-progress to shipping containers to individual retail packages, concrete applications have lagged behind forecasts. 

RFID tagging requires a substantial investment in both the tags themselves and the supporting infrastructure of readers, data management software, and so forth. The benefits of tagging may not be realized until every item that moves through a facility is tagged, which often means that many different vendors and customers must support the project. In an airport baggage handling facility, for example, untagged pieces of luggage might have to be placed in tagged bins. The added costs of handling untagged items would offset some of the benefits of tag-based handling.

Meanwhile, ongoing weak global economic conditions have slowed all forms of business investment. Expensive projects with uncertain financial returns will continue to move slowly as long as economic conditions remain poor. At the same time, even with relatively slow adoption rates of adoption the market has already progressed to the point where many businesses and consumers are at least somewhat familiar with RFIDs. Millions of people use RFID-based tags to pay highway tolls and transit fares electronically; millions of dollars worth of high-value manufacturing depends on RFID-based WIP tracking.

Applications like RFID-based toll payment systems often add a battery, the second of our three components. While passive tags are only readable from a relatively short distance, powered tags can actively transmit to a reader some distance away. Powered tags are also appropriate for locations — such as inside vehicles and shipping containers, or inside livestock — where large quantities of metal or water reduce signal strength. These tags often appear in permanent or semi-permanent installations, and as a result the required battery life can be between three and five years or even longer. Such tags are expensive, however, and therefore not really suitable for disposable applications like smart shipping labels.

Hence the importance of our second key innovation, printed batteries. While conventional button batteries encase the electrodes and electrolyte in a metal can, printed batteries typically screenprint these layers onto a plastic (or even paper) substrate, then seal the battery with a second plastic film. Though they offer less storage capacity than conventional batteries, their solid-state nature makes them more durable and easier to integrate with smartcards, smart labels, and other low profile devices. Simplified integration, in turn, helps drive down the overall cost of systems containing printed batteries. While printed batteries do not yet offer the performance needed by active RFID tags, they offer compelling cost reductions for disposable applications. A battery-assisted tag may offer a compelling compromise between the performance and lifetime of active tags and the low cost of passive tags. Indeed, Nanomarkets expects battery-assisted RFID tags will be one of the leading markets for printed batteries for the duration of our forecast.

Once an inexpensive power source is available, many other applications become possible. With a battery, an RFID-tagged shipping label becomes an autonomous device, able to perform independent tracking and monitoring functions as the package moves through the global shipping system.

Cold chain management is one of the first smart label applications to appear. More than $30 billion in meat, seafood, and cheese is lost to spoilage each year, along with a similar amount of fruit and vegetables and more than $5 billion in pharmaceuticals. While it is easy to tell if a frozen package is thawed when it reaches its destination, cold chain failures are usually less obvious. A package of fish might have been sitting on a sunny loading dock for several hours in transit, for instance. Though re-frozen by the time it reaches the destination, it might already have degraded, or might have a shorter remaining storage life than expected. A medicine intended for a remote village might become less effective or even dangerous if not stored properly. Without in-package monitoring, there’s no easy way to tell that the cold chain was compromised somewhere along the way.

Which is where our third important innovation, sensors, enters the picture. Once a power source is available, combining a temperature sensor with a timing circuit allows the smart label to record its temperature at regular intervals, storing the information in the RFID tag’s memory where it can be read at the destination. Because the label is remotely readable, it can be sealed inside the package, at the same ambient temperature as the contents. Given the thermal history, the recipient can decide whether to accept the shipment without inspecting the contents. A more sophisticated device could generate an electronic alert if it detected an out-of-specification temperature, allowing corrective action before degradation of the package contents occurred.

One commercial example is the Sealed Air Turbo Tag, powered by a battery from Blue Spark. PowerID, spun out from Power Paper in 2007, focuses on tagging and smart packaging applications as well. In addition, Enfucell is collaborating with Finland’s RFID lab to develop tagging and smart packaging applications of RFIDs. This spring the company shared in a grant to Europe’s Ropas consortium, aimed at development of wireless sensors printed on paper.

The basic combination of a battery, a sensor, and an RFID tag could be applied to other types of packages as well. Precision optical and mechanical devices are very sensitive to vibrations; incorporating an accelerometer into the shipping label could show whether a package had been shaken or dropped. With potentially hazardous cargo, smart labels could alert the shipper to possible leaks or to conditions that might rupture the shipping container.

As the key components of smart labels mature, we expect what is now novel — as is often true — will become commonplace. Devices once used for high value shipments could eventually make their way into picnic coolers and boxes of holiday cookies. But for now, printed batteries are helping smart labels take the first steps from concept to commercial reality.