Design,Construction And Evaluation Of Wearable Thermoelectric Device Test System

In recent years,the economy has developed rapidly,traditional energy has been widely used,and the problems of environmental damage and shortage of resources have become more worse.It is urgent and necessary for us to find new renewable energy sources.Meanwhile,thermoelectric materials have received extensive attention as new green and clean energy materials.Thermoelectric materials have many advantages such as high reliability and no pollution.Thermoelectric materials are a perfect solution to solve the problem of environmental pollution.This has also led to the rapid development of thermoelectric devices.Thermoelectric devices originally used for space exploration have gradually entered daily life,especially in the field of health testing in the medical field,which has unique advantages.At present,the preparation technology of wearable thermoelectric power generation devices has developed extremely rapidly,but there is still no standard for the testing technology of the power generation performance of the devices,and the performance evaluation methods of the devices are too confusing.Therefore,it is very important to establish an evaluation system for thermoelectric power generation devices.This paper aims to establish a wearable thermoelectric power generation system test platform and corresponding characterization techniques,and systematically research the influence of platform parameters on the power generation performance of the Thermal Electric Generator.The main contents and conclusions are as follows:(1)Starting from the power supply system,the environmental control system,the device testing system and the data acquisition system,the requirements for each system to meet the test conditions are put forward respectively;The overall architecture design and specific test process of the thermoelectric power generation system performance test platform are introduced in detail,and the instrument selection is completed according to the functional requirements of each part of the subsystem.The construction of the wearable thermoelectric power generation performance test platform is completed;(2)After the test platform is built,it is necessary to conduct stability and reliability experiments on the environment of the test platform.The results after Initial certification show that under the low temperature environment,the air convection heat transfer coefficient is large,the test environment is unstable,and the high temperature environment is relatively stable;In the same way,the temperature of the cold end of the device is relatively stable under the low wind speed environment;the reliability test results show that the maximum deviation of the test results is 0.8℃with different ambient temperatures,and the maximum deviation of the test results of the wind speed reaches 0.23 m/s;Eight repeated tests were carried out on different ambient temperatures and wind speeds respectively,and the results showed that the accuracy of power generation performance tests in high temperature and low wind speed environments was higher;The data of the repeatability test was used to conduct uncertainty analysis.Under the low temperature environment,the uncertainty of the maximum open circuit voltage and peak power tested were the largest,which were 1.24and 0.015.It can be seen that the test accuracy of the low temperature environment is slightly worse than that of the high temperature.In the low wind speed environment,the uncertainty of the measurement results is the smallest.The uncertainty of the maximum open circuit voltage and peak power are 1.74 and 0.014 respectively,but they are still significantly higher than the maximum value under the ambient temperature test.It shows that the change of wind speed will be larger than the fluctuation caused by the ambient temperature;(3)Then,the influence of test platform conditions on the power generation performance of the Thermal Electric Generator is researched.First,the influence of environment temperature and environment speed on the power generation performance of the Thermal Electric Generator was researched.It was found that the environment temperature was lowered,and the power generation performance of the Thermal Electric Generator was improved.The effect of temperature is smaller when the ambient temperature is in the lower range.The power generation performance of the device increases with the increase of wind speed,but in a low temperature environment,the power generation performance of the device decreases;secondly,the control variable method is adopted to regulate the water flow rate,water temperature,silicone thickness and wearable pressure.The results show that with the increase of water flow rate,both open circuit voltage and power increase;increasing the water temperature will indeed improve the power generation performance,but the increase in the power generation performance is not large;the smaller the thickness of the silica gel,the better the performance,but if the thickness is too low,the surface of the silica gel will be uneven,which will cause poor contact between the device and the silica gel,and the test results will be inaccurate.Applying greater pressure will generate greater open-circuit voltage and power,but applying pressure greater than 0.75 KPa has no greater benefit in improving power generation performance;(4)The parameters are adjusted to be comparable to the real arm of the human body,and since the wearable pressure is not affected by the environment,the pressure of 1.0 KPa is the first to be determined.On this basis,we adjusted different ambient temperatures to determine the water flow rate,water flow temperature and thickness of silica gel,and the thickness of silica gel of 7 mm was considered to be the most suitable.When the ambient temperature is 5℃,14℃,21℃and 32℃,the water flow rate is adjusted to 0.03 m~3/h,0.04 m~3/h,0.05 m~3/h and 0.06 m~3/h respectively,and the water temperature is 42℃,41℃,40℃and 39℃;Finally,the accuracy of the platform test in different seasons was studied,and the specific meteorological data on March 8,July19,October 25,and December 18,2021 were queried.Set the corresponding environment respectively,compare the output power of the test platform and the human arm in the same environment.The results show a high degree of agreement,which suggests that the bionic simulated arm developed in this work has the potential to objectively evaluate the performance of wearable TEGs.