Smart watches and wristbands are helpful in health monitoring, sport training, living assistance, etc. However, due to critical size limitation and high-power requirement, battery endurance becomes a big issue that the devices need to be frequently recharged, which even causes “battery anxiety” among the users. Although capturing the kinetic energy from arm swinging renders a promising solution, it’s a challenging task to produce high power in a limited size. To achieve this, we invented an embedded and highly efficient generator with coaxial topology to integrate motion capture unit, magnetic frequency-up converter and power generation unit in a thin and compact device, which allows it to be embedded in the smart watches and wristbands. Despite of integrating several parts in a highly compact device, the mechanical structure is concise and easy for fabrication. At the same time, to increase the energy efficiency, the mechanical friction is reduced by using magnetic transmission and compact skew-ball-like bearing. The testing results showed that our embedded generator can achieve maximum power of 1.74 mW and normalized power density of 820.38 μW/cm ·Hz , which are more than 4 and 10 times that of the counterparts.

智能手錶和手環在健康監測、運動訓練和生活助理方面頗有幫助。但是，受限于體積和高功耗要求，它們電池的續航時間不足並需頻繁充電，這引起用戶電池焦慮的問題。儘管從手臂擺動俘獲動有望解決該問題，但利用有限體積產生足夠電能有諸多挑戰。因此，我們發明具有同軸拓撲結構、高效緊密的嵌入式發電機。該發電機將運動俘獲單元、磁性升頻器和發電單元集成于扁平緊密的裝置，從而使其可嵌入智能手錶和手環。儘管緊密集成若干單元，該發電機結構簡單、易於加工。同時，爲了提高效率，使用磁性傳動和緊密的軸承降低摩擦。測試結果顯示該發電機可產生最大1.74 mW的功率和820.38 μW/cm ·Hz 的標準化功率密度。發電功率和標準化功率密度高達競爭產品的4倍和10倍。