Researchers explored the possibility of embedding microbatteries directly into sensor circuitry, providing a built-in power source instead of an external one.
Newer applications like fitness trackers and wireless sensor networks call for compact devices with high energy-density batteries. Batteries occupy the most space in devices like these, and thus high-capacity microbatteries are needed to power these devices, while still maintaining compactness.
These systems, moreover, rely on small sensors already numbering in the hundreds of billions. The sensors measure changing conditions and report the data electronically. These sensors are powered by ultra-small batteries. As the pace of miniaturization and its applications accelerates, so does the need for ever-smaller sensor batteries that can last a lifetime.
Kristofer Pister, professor of electrical engineering and computer science at University of California, Berkeley, leads the research on embedding microbatteries (about the thickness of three sheets of paper) directly into sensor circuitry, providing a built-in power source instead of an external one. This approach allows for more compact circuit boards to make the sensor, microprocessor and battery all one unit that can speak to the internet.
Pister says, “The number one requirement for batteries is connectivity. You have to get the data back to where it needs to go. And you need to do it reliably. The microbatteries we are developing pack a lot of power into a smaller package. They’re also lighter than current batteries and cheaper to produce. Manufacturing them uses the same fabrication and circuit printing technology already used to make trillions of chips.”
The circuit is stencil printed on silicon wafer, which is a similar process as making screen-printed t-shirts.
Pister says, “They would work very well for wearables, where comfort and appearance are important. As just one example, they are a natural for applications like smart bandages to monitor wound healing by assessing the healing process of the wound environment. We think this batteries-in-a chip design will be part of devices in the full range of commercial spaces.”