Battery-Free ECG Patch Enables Continuous Arrhythmia Monitoring

Battery maintenance also limits long-term adherence and increases device size, reducing comfort for patients across care settings. Reliable, body-friendly power delivery is therefore a central barrier to scalable physiologic monitoring. To help address this challenge, engineers have developed a skin-conformal, battery-free ECG system that operates using energy harvested elsewhere on the body.

SkinECG, created at Seoul National University, is a skin-adherent hydrocolloid patch that integrates a flexible circuit board and a custom semiconductor chip for ECG sensing. The system draws power from an Orthogonal Energy Harvesting Network (O-EHN) that aggregates energy from one or more body-worn harvesters and wirelessly transfers it to a chest-mounted sensor. Rather than radiating power through air, it uses body-coupled power transfer to guide energy along the skin, while distinct frequency channels limit interference among multiple harvesters.

The design resolves the long-standing location mismatch between optimal sites for energy harvesting and ideal sites for biosignal acquisition. Energy can be collected on exposed areas such as the arm or leg and delivered to the chest without wires or batteries. Power coupled to the body is kept at levels comparable to everyday ambient electromagnetic exposure, supporting human safety while maintaining stable reception at the sensor.

Demonstrations paired a solar cell–based module with a chest-mounted patch to achieve battery-free ECG measurement. The architecture reduces constraints on the number and placement of harvesters and remains compatible with existing commercial energy-harvesting components, supporting broader wearable use. The researchers note that the approach is extendable to electromyography (EMG) and electroencephalography (EEG) sensing and may also inform future implantable and wearable power solutions. The work, conducted with collaborators at the University of Tokyo and the National University of Singapore, is published in Science Advances.

“In wearable health care systems, there has been a fundamental limitation in that the optimal locations for harvesting ambient energy and for measuring physiological signals are different. This study resolves that issue by enabling wireless power transfer along the surface of the human body,” said Jerald Yoo, professor in the Department of Electrical and Computer Engineering at Seoul National University.

"By limiting the power coupled to the human body to levels comparable to those encountered in daily life, we designed the system with human safety in mind while demonstrating stable power delivery to ECG sensors without bulky batteries. This approach can be extended to multimodal digital health care platforms capable of operating various biosignal sensors such as EMG and EEG, as well as to broader wearable power supply technologies," said Prof. Yoo.

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