The micro-batteries that provide the technical foundation for wearables have developed by the researchers at Fraunhofer Institute for Reliability and Microintegration IZM. In medicine, wearables are used to collect data without disturbing patients as they go about their daily business - to record long-term ECGs, for instance. Since the sensors are light, flexible and concealed in clothing, this is a convenient way to monitor a patient’s heartbeat. The technology also has more everyday applications - fitness bands, for instance, that measure joggers’ pulses while out running. There is huge growth potential in the wearables sector, which is expected to reach a market value of 72 billion euros by 2020.

The researchers have developed a prototype for a smart wristband that, quite literally, collects data first hand. The silicone band’s technical piece de resistance is its three gleaming green batteries. Boasting a capacity of 300 milliampere hours, these batteries are what supply the wristband with power. They can store the energy of 1.1 watt-hours and lose less than three percent of their charging capacity per year.

With these parameters the new prototype has a much higher capacity than smart bands available at the market so far, enabling it to supply even demanding portable electronics with energy. The available capacity is actually sufficient to empower a conventional smartwatch at no runtime loss. With these sorts of stats, the prototype beats established products such as smart watches, in which the battery is only built into the watch casing and not in the strap.

Instead of making the batteries extremely pliable at the cost of energy density and reliability, the institute turned its focus to designing very small and powerful batteries and optimized mounting technology. The batteries are pliable in between segments. In other words, the smart band is flexible while retaining a lot more power than other smart wristbands available on the market. 

Fraunhofer IZM combines new approaches and years of experience with a customer-tailored development process: The researchers work with companies to develop the right battery for them. The team consults closely with customers to draw up the energy requirements. They carefully adapt parameters such as shape, size, voltage, capacity, and power and combined them to form a power supply concept. The team also carries out customer-specific tests.

In 2018, the institute began work on new wearable technology, the smart plaster. Together with Swiss sensor manufacturer Xsensio, this EU-sponsored project aims to develop a plaster that can directly measure and analyze the patient’s sweat. This can then be used to draw conclusions about the patient’s general state of health. In any case, having a convenient, real-time analysis tool is the ideal way to better track and monitor healing processes.

Fraunhofer IZM is responsible for developing the design concept and energy supply system for the sweat measurement sensors. The plan is to integrate sensors that are extremely flat, light and flexible. This will require the development of various new concepts. One idea, for instance, would be an encapsulation system made out of aluminum composite foil. The researchers also need to ensure they select materials that are inexpensive and easy to dispose of. After all, plaster is a disposable product.