The thermoelectric devices utilize stretchable human health detection implemented cogeneration

I. Background

due to the increase and the world\’s current energy consumption of fossil fuel scarcity, geothermal and other renewable energy as a sustainable electricity supply concern, in addition to industrial production and most of the heat produced by the body are wasted. The thermoelectric generator (TEG) may convert waste heat to usable electric energy, and further recovering waste heat to help improve energy efficiency. Further, the heat collector may be implantable and wearable device to provide a basic solution to biological energy low power. The most widely used of the thermoelectric (TE) material is a metal oxide and a highly doped metal alloys. Traditional method of producing the TEG and hot zone melting, both methods produce a high quality factor (ZT) value. However, the energy conversion efficiency and power output are highly associated with heat transfer between the heat source and the TEG, especially in complex and dynamic surface. Due to limitations of conventional plate structure, TE materials can not form an effective heat transfer contact with the hot surfaces of complex and dynamic. Thus, subject to widely TEG complex and dynamic heat transfer efficiency of the heat surface. To solve this problem, researchers may be prepared by bonding a flexible surface of the TEG simple, however, they are not suitable for more complex and dynamic non-developable surface. Furthermore, for other TEG (by 3D printing and spray coating), dynamic tensile deformation of the surface of these electrodes may result in excessive damage to the TEG. In contrast, the stretchable TEG can work on the dynamic surface, but the present study is to use the TE or doped silicon material is deposited on a paper / polymeric substrate, this will lead to higher internal resistance and lower output power density. Current, high power TEG how to make use of in the complex and dynamic hot surfaces remains a challenge. To solve this problem, Wuhan University, the University of Southern California (USC), San Diego State University (SDSU) and the University of California, San Diego (UCSD) to develop a An extensible TEG ( S-TEG) ​​, it can effectively fit a variety of complex and dynamic hot surface, the researchers tested the device on the body surface and the dynamic applicability skin was collected using S-TEG waste heat source provided to detect motion, heartbeat and the like health monitoring gesture event to the sensor. Related outcomes to \”Stretchable Nanolayered Thermoelectric Energy Harvester on Complex and Dynamic Surfaces \”in the title, published in\” Nano Letters \”on (Nano Lett. 2020, https://dx.doi.org/10.1021 /acs.nanolett.0c01225). Assistant Professor of mechanical Engineering at San Diego State University, Yang Yang , Ph.D., University of California, San Diego Hongjie Hu and the Central South University professor Chen Zeyu as co-first author of the paper, Wuhan University Industrial Technology Research institute Research Associate Wang Ziyu , an assistant professor at the University of California, San Diego Sheng Xu and University of Southern California professor Yong Chen for the paper co-corresponding author, participants include the University of Southern California professor Qifa Zhou , postdoctoral Laiming Jiang , Ruimin Chen , Dr. Gengxi Lu , [ 123] Jie Jin , Haochen Kang , Arizona State University assistant professor Xiangjia Li and the Wuhan Institute of Physics, University Professor Xiong Rui , stone Jing Professor . 可拉伸热电器件利用人体废热发电实现健康检测

Second, the graphic REVIEW FIG. 1A shows the silicon substrate 10 × 25 mm × 25 mm of collecting energy from waste heat in human skin 10 TE schematic coupled array. S-TEG formed in parallel and electrically in series with a pn hot leg and made of a rectangular parallelepiped .pn \”Island bridge\” layout of the electrodes assembled together, and embed in compliance super drawing silicone elastomer (of Ecoflex) (Figure 1B). in order to balance the performance of the thermoelectric device and stretchability, the cuboidOptimization of the size of 1 mm × 1 mm × 0.8 mm, to show a higher ΔT and greater stretchability. Stretchable electrode manufactured by laser ablation. The whole device can be folded, twisted and stretched, without breaking, it shows high tolerance to skin deformation.

可拉伸热电器件利用人体废热发电实现健康检测 Figure 1. stretchable TEG (S-TEG) ​​The design and application. (A) schematically shows the S-TEG collecting energy from waste heat human skin; and in the drawing, an optical image of the device and an exploded view show the 10 × 10 array of p-n device structure of the TE material and a unit. (B) Optical image display design details (R) S-TEG layout (left) and the serpentine electrodes. (C) Ecoflex different thicknesses load – strain curve (the size of all the samples were 25 mm × 25 mm). (D) attached to the convex surface analog having different size and thickness (length in the range of 1-5 mm, a thickness of from 0.1 mm to 0.8 mm) temperature difference ([Delta] T) top and bottom surfaces of the rectangular parallelepiped block TE.
Most of flexible TEG only on the surface of the expandable used, it is difficult to adhere well to the non-developable surface, in particular the need for the device to stretch from 30 to 40% of the elbow and joints. Here further demonstrates the application of S-TEG on a non-developable surface, by fixing the device on a 90 degree elbow and tee (FIG. 2). The results show, S-TEG and having excellent adhesion properties can not be developed on the surface of these, and the pair of conventional planar flexible TEG is challenging. The elbow in S-TEG circuit voltage and the output power per unit area increases with increasing [Delta] T, respectively, when reached ΔT = 19.7 K 117 mV and 0.15 mW / cm

2 (Figure 2E). S-TEG open circuit voltage and power on the tee and 110 mV respectively 137.5μW (ΔT = 18.9 K) (FIG. 2F). S-TEG on hot surfaces of the expandable and non-expandable have excellent performance, due to their excellent stretchability, and can be attached to the surface to ensure that heat transfer from the waste heat, which is essential for energy collection.

可拉伸热电器件利用人体废热发电实现健康检测 FIG. 2. S-TEG and the static surface integrated in the complextogether. (A) shows a schematic view of 45 ° and 90 ° elbows, tees and cross joint with a hot water pipe. (B) = 28 mm in diameter is R1 Seebeck voltage generated in the tube, and the output voltage and power of the S-TEG at various temperature differences on the tube 1. Shows a schematic view of a simulated using Comsol Multiphysics deployable upper surface of the heat transfer and the output voltage of the S-TEG (C) and conventional planar TEG (D), showed greater heat energy storage and conversion of S-TEG. (E) S-TEG attached 90-degree elbow, the voltage and power output varies with temperature. (F) S-TEG fixed to the tee, the output voltage and power variations with temperature, S-TEG exhibit excellent thermoelectric properties in the non-developable surface.
In addition, S-TEG excellent performance tests on human skin, the skin is not only complex and highly curved, but also has the dynamic characteristic time. Wearable device has an important application in the TEG, since the skin temperature and ambient temperature differential will provide a natural, can derive energy (FIG. 3A). S-TEG also been tested as energy solutions wearable device. And FIG. 3D shows a schematic of the electronic circuit design and S-TEG Flex (bend-sensitive resistors) and a force sensor (pressure-sensitive resistor) connected in series. The initial resistance of the force sensor is R1 = 1MΩ, and the resistance will increase as the pressure decreases. At a constant value R2 = 50 KΩ, the output voltage varies with pressure. S-TEG for collecting energy from dynamic human wrist. It provides for the connection of a voltage signal of the force sensor chest to monitor heart rate of the output voltage of ~ 27 mV (FIG. 5E).
可拉伸热电器件利用人体废热发电实现健康检测 Figure 3. The performance of dynamic S-TEG hot surfaces. (A) an infrared image of the human finger and wrist S-TEG to demonstrate the device on a dynamic thermal surface. (B) S-TEG energy collected on the dynamic surface of the human body. (C) an enlarged image display attached to the S-TEG with stretch bending the finger electrode and the silicon of the balloon. (D) S-TEG as presentations and associated electronic circuit design wearable device energy solutions. (E) is mounted on the chest with a snapshot S-TEG connected to a force sensor (force sensitive resistor) is (attached to the wrist), not toAt the same time health monitoring heart rate detection, respectively a rest, walking and running test, the snapshot will be grouped together in FIG. (F) to the force sensor S-TEG (connection on the wrist), and water used in operation (R2 equal to 50K) detects the pressure of the finger. (G) and S-TEG (attached to the wrist) connecting bend sensor (bending sensitive resistor) for detecting movement and different finger gestures (R2 equal to 10KΩ).

Third, the highlight summary In conclusion, the researchers describes a dynamic and adaptable complex surface heat stretchable TEG design and manufacturing. The powder was hot pressed to obtain high performance TE p-n elements and undulating serpentine conductive network provides great stretchability for the device. The flexible substrate and the electrodes may be implemented to ensure a good S-TEG adhered to the hot surface of the complex topography of the stretching process, the S-TEG in the non-deployed and deployable upper surface exhibited excellent performance. Its performance is superior to STEG previously reported. Collecting energy from the dynamic surface is a human S-TEG wearable electronics offers a potential energy solutions. May also be coupled through the p-n doubled, or by connecting a plurality of modules of energy to manufacture large and collecting waste heat from the TEG devices daily life and industrial engineering. Article link: https: //pubs.acs.org/doi/10.1021/acs.nanolett.0c01225

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