No Batteries: Health Sensor Harvests Biomechanical Energy

An international team of researchers has developed a wearable health monitor that works without the need for batteries. Instead, piezoelectric nanogenerators in the tiny smart patches harvest energy generated by bodily movements during daily activities.

There’s a booming market for wearable healthcare technologies—electronic devices such as smartwatches that have been designed to collect personal health data. However, navigating the power requirements of these devices has been challenging, with the tradeoffs often being comfort and convenience.

In a breakthrough development, researchers have created an ultraflexible patch that measures the wearer’s pulse and blood pressure. Most critically, the device is battery-free—natural motion is converted into small electrical voltages in the device's ferroelectric polymer core.

According to the inventors, the smart patch can harvest around 200 millijoules of energy per day, if attached to a joint such as the elbow or knee. This amount of energy is sufficient for capturing pulse and blood pressure measurements several times a day. The small patches are also so thin that they are barely perceptible, making it comfortable and inconspicuous enough for continuous wear.

The first author of the publication, Andreas Petritz says there are multiple potential applications of this new technology: "Our ehealth patches may be employed as part of screening for lifestyle-related diseases such as heart disorders, signs of stress, and sleep apnea."

Sources: Nature Communications, Osaka University.