Thin printed batteries spark new product innovation
Blue Spark Technologies’ customizable 1.5-V carbon-zinc batteries provide a reliable, eco-friendly power source for numerous applications. The company’s battery technology is built on patented intellectual property acquired from the Eveready Battery Company (now Energizer).
In a tight economy when manufacturers need to focus on reducing costs while increasing efficiency and speed to market, continuing to support new product development and innovation can be a challenge. Fortunately, in the field of electronic design, new technologies are constantly emerging that can help lower development costs and simplify production processes.
Two of these rapidly growing technologies are printed electronics and thin, flexible printed batteries. Printed electronics can be defined as the printing of electronic devices on common media, such as paper, plastic, or textiles, using traditional printing processes. Examples include programmable chips (ICs), RFID antennas and tags, printed displays, and thin, flexible batteries that provide a low-voltage power source.
Industry analyst IDTechEx forecasts the market potential for printed electronics at over USD $35 billion by 2018. NanoMarkets, another analyst, predicted that sales of thin film and printed batteries will exceed USD $5 billion by 2015. Clearly, printed electronics is a technology on the path to global acceptance — with eco-friendly carbon-zinc printed batteries playing an integral role.
Thin printed battery chemistry
Low-voltage, carbon-zinc batteries are typically printed on a recyclable plastic PET base using carbon, zinc, and manganese dioxide materials. The anode material is a laminate of zinc foil and the cathode material is a manganese dioxide paste mixed with carbon. After a separator is placed atop the printed design, a couple of drops of electrolyte are added, and a top layer of PET is used to seal the battery cell. Power generation in the battery results from a chemical reaction between the electrolyte liquid and other materials.
Sealed Air Corporation’s TurboTag RFID time-and-temperature system uses a sensor device and battery-powered “smart” card to ensure cold chain compliance in food and beverage, chemical, and pharmaceutical supply chains. The system uses Blue Spark ST printed batteries to support the silicon chip’s data logging functionality.
While this may sound complex, it can be done relatively quickly and cost effectively. The batteries are produced using high-speed, roll-to-roll printing processes, which means they can be prototyped and mass-produced quickly and economically. This scalability makes it possible to achieve economies of scale as product development advances from pilot test quantities to high-speed, high-volume production.
In use, printed batteries function as primary power cells. They are not rechargeable, but may be safely stored in cold storage after manufacturing to slow the chemical reaction in the battery, thereby extending its shelf life. For product designers of low-voltage electronic products and systems, the 1.5-V printed batteries offer multiple advantages over traditional button and coin cells. These include:
- Eco-friendly, safely disposable. Unlike traditional batteries, they are completely “green,” containing no lithium, mercury, or other toxic materials. This is becoming increasingly important as the quantity of electronic devices on our planet continues to grow and global environmental regulations become ever-more stringent.
- Small form factor, thin profile, customizable shapes. Printed carbon-zinc batteries range from about 430 to 700 microns (0.017 to 0.027 in.) thick and are typically capable of delivering peak drain currents of at least 1 mA. Batteries supporting higher drain currents, and designs with voltages above 1.5 V, can also be supplied. They can be used in applications where conventional batteries just won’t fit or where integration of a conventional battery would be too complex and costly. Within limits, users can typically specify size and shape (linear and non-linear), overall voltage, storage capacity, and thickness — all tailored to the application requirements.
- Lower production and integration costs. Because they are made using conventional printing processes, thin printed batteries are typically less costly and faster to produce. The battery can often be printed or mounted on the same substrate as other printed electronics (IC chip, RFID inlay/antenna), so assembly and integration of the electronic elements into products is also faster, easier, and less expensive.
The question often arises on how printed carbon-zinc batteries compare to low-voltage coin and button cells from a cost, price, and performance basis. For applications such as smart cards and BAP RFID, it’s simple, because coin and button cells just won’t fit. The size, thin profile, and flexibility of printed batteries make them the obvious choice.
This prototype battery-assisted passive (BAP) RFID inlay, jointly developed by UPM Raflatac and Blue Spark Technologies, is EPC Gen2 compatible. In testing, it has proved capable of battery-assisted read ranges up to 50 m (154 ft) and features 1,024 bits of non-volatile memory. BAP RFID effectively bridges the gap between pure passive RFID technology and high-end active and real-time location systems (RTLS), from both a price and performance standpoint.
In other applications, cost is a primary factor. Coin and button cells are mature in their product lifecycle and low price options are available. However, in evaluating battery options, designers need to consider the total cost of integration with the product. With coin cells, the costs related to purchasing retaining clips/holders, soldering the battery to a rigid circuit board, and insertion of the battery must be considered. These factors can increase total cost up to several times the price of acquiring the actual coin or button battery.
The ease of integrating printed batteries into products allows higher levels of automated production. And, in some cases, integration costs can be further reduced by printing the battery on a shared substrate with other electronics, such as displays, ICs, and RFID inlays.
Powering a world of product applications
Standard and customized printed carbon-zinc batteries are currently being deployed and pilot-tested across diverse industry sectors. Common applications are:
- Battery-assisted passive (BAP) RFID. Sometimes called semi-passive, BAP RFID can significantly extend the capabilities of RFID tags without incurring the expense of active RFID. The battery boost improves read ranges and tag readability — especially with RFID-unfriendly materials such as liquids and metals, or where individual tagged items are densely packed or stacked. BAP RFID systems can also provide greater memory and data security, making them a high-value choice for inventory and asset tracking of raw materials, finished goods, irreplaceable files, valuable tools and equipment, and the like.
- RF-enabled sensor and data logging systems. These portable systems are increasingly popular with manufacturers and distributors of food, pharmaceuticals, chemicals, and other temperature-sensitive goods. For example, Sealed Air Corporation uses thin, flexible printed batteries from Blue Spark Technologies to activate the data logging function of its TurboTag RFID Time-and-Temperature Monitoring System, which ensures cold chain temperature compliance of perishable goods from the point of origin to points of delivery. Such systems could also be designed and programmed to monitor vibration, humidity, or other ambient conditions critical to product safety and quality.
- Smart packaging. Printed carbon-zinc batteries are well suited to a wide range of intelligent packaging, especially since the batteries can often be printed in-line with traditional package printing. According to NanoMarkets, applications for battery-powered packaging may eventually encompass: pharmaceutical compliance packaging, case-and-pallet freshness monitoring devices, and tamper-proof courier packages. Printed batteries could also be used to power an LED or voice-activation device in consumer goods packaging — such as cereal boxes and frozen dinners — to drive sales by engaging consumer attention.
- Powered “smart” cards. Today, there are about four billion plastic smart cards containing programmable chips being produced annually worldwide. Driving this growth is the need for increased security and authentication, the growing acceptance of contactless payments, and consumer preference for wallet-size cards that integrate visual, interactive, and tactile innovations. Battery-powered cards enable card companies to incorporate lighted or color-changing displays, stored value and account status information, authentication codes (such as one-time passwords), and other interactive functions.
Health care and cosmetic applications are also under development — specifically battery-powered transdermal patches for consistent delivery of medications for smoking cessation, wrinkle reduction, and the like. Another potentially profitable market is high-volume consumer novelties. Products such as musical and self-recorded greeting cards, and interactive printed media, such as books, posters, games, and trading cards, can be programmed to interact with purchasers via sight, sound, and touch. This impulse-driven consumer market could be a very attractive target for printed electronics and thin printed batteries.
Business value delivered
According to many analysts, printed electronics is projected to revolutionize major segments of the electronics industry, and low-cost disposable batteries are essential to this transformation. Speed of adoption will depend largely on alliances formed by leading developers of electronic devices, who are already working to develop solutions that leverage the capabilities of printed electronics for business value. As a result, we can look forward to the creation of innovative new products and systems for consumer, industrial, financial, security, food, pharmaceutical, health care, and other markets.
So, tough economic times need not signal the end of product innovation. In fact, there may be no better time to focus on expanding product choices by harnessing innovative technologies that can help bring products to market faster and with lower development and production costs — technologies like printed electronics and thin printed batteries.
About the author
Matt Ream is marketing manager for Blue Spark Technologies, a leading developer of flexible, eco-friendly proprietary power source solutions for battery-powered printed electronic systems. As an electronics engineer, Ream has 20 years of experience in high-tech electronics and radio frequency identification (RFID) and has held senior positions in engineering, product research and development, and marketing.
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