Mountaineers, soldiers, and school children know the burden of a heavy backpack. Now, researchers have developed a prototype that not only makes the load feel 20% lighter, but also collects it to feed low-energy electronics from human movements. New backpack ACS Nanothe researchers say it could be useful for athletes, explorers and disaster rescuers working in remote areas without electricity.
Backpacks are widely used in everyday life to carry loads freely. Over time, however, walking or running with a heavy sack can cause back and neck pain. Also, backpackers in desert areas (or even in cities with no easy access to the charger) want a bag to collect mechanical energy to walk on to power portable electronics or sensors to control health. Previously, researchers used triboelectric nano-generators (TENGs) – small devices that convert mechanical energy into electricity – to make energy-backpacking backpacks, but these bags had relatively little output and did not provide added advantages such as load relief or shock absorption. Zhong Lin Wang, Jia Cheng and colleagues wanted to design a prototype that transcended these boundaries.
To save labor and absorb shock, the researchers put two elastomers that were stretched and shredded into the backpack while he was wearing them while keeping the bag stable. This reduced the strength of the user by about 20%. Meanwhile, moving between the backpack frame and its load propelled a TENG to convert mechanical energy into electricity, with an efficiency of 14%. The researchers showed that the bag could turn on LEDs, an electric clock and fluorescent tubes. Researchers say that overcoming some of the challenges, such as improving energy conversion efficiency, has promising potential as a source for small-scale portable and portable electronics, GPS and health sensors.
Reference: Ze Power, Yiyong Yang, Fan Liu, Zhaozheng Wang, Yinbo Li, Jiahao Qiu, Xuan Xiao, Zhiwei Li, Yijia Lu, Linhong Ji, Zhong Lin Wang and Jia Cheng “Electric impact backpack for energy collection and charge reduction”, 2021 February 3, ACS Nano.
DOI: 10.1021 / acsnano.0c07498
The authors acknowledge the funding of the National Foundation for Natural Sciences of China, the China Science and Technology Master Project, the National Key Research and Development Program of China, and the Scientific Research Program of the Tsinghua University Initiative.