Effects Of Environmental Factors And Vacuum Degree On The Performances Of Voltaic Microbatteries

In recent years, microelectromechanical systems(MEMS) have developed quickly and played an important role in the rapid development of military, aerospace, biomedical, industrial, and agricultural fields. As a kind of micropower, voltaic microbatteries have potential long life, high energy density, stability, miniaturization, no external power supply, which make them effective to supply energy to MEMS. Therefore, voltaic microbatteries have important research value. This thesis focuses on the manufacture of voltaic microbatteries, the effects of tenmperature and the vacuum degree on the different types of voltaic microbatteries. The maincontent was summarized as follows:1) Based on the working principle of the voltaic microbatteries, different types of structure and the common radioactive sources and energy conversion devices, the energy conversion devices were prepared by micro-nano processing technology, and PCB, conductive silver adhesives, wire bonding and radioactive sources loading were also prepared, so different types of voltaic microbatteries were obtained finally.2) Four kinds of betavoltaic microbatteries were obtained based on different radioactive sources and energy conversion devices. The effect of temperature on the output performance of four different types of betavoltaic microbatteries was investigated experimental and theoretical. The short-circuit current density increases slightly and the open-circuit voltage decreases evidently with the increase in temperature. Different combinations of energy conversion devices and beta sources cause different effects of temperature on the microbatteries. In the approximately linear range, the VOC sensitivities caused by temperature for 63Ni–Si, 63Ni–GaAs, 147Pm–Si, and 147Pm–GaAs betavoltaic microbatteries were-2.57,-5.30,-2.53, and-4.90 mV/K respectively. Both theoretical and experimental energy conversion efficiency decreased evidently with the increase in temperature. The more times the heating temperature cycles, the worse the performance of the battery would be. Based on these experiments, the optimizing preparation of energy conversion device and the upper electron with gate type were researched.3) For betavoltaic and alphavoltaic microbatteries, the effects of the vacuum degree during different air distance between radioactive sources and energy conversion devices were researched by Geant4. For 63Ni-Si and 241Am-Si, the relationships between the deposition energy and the vacuum degree were calculated. With the increase of the pressure, the output performance dropped slightly and fell at a faster pace. Then, the relationships between the other characteristic parameters and the vacuum degree were also obtained. Experimental research on the effect of the vacuum degree was carried out on 147Pm-Si. It shows the vacuum degree has great influence on the output of voltaic microbattery.The research of this thesis supplies a basis for the manufacture and the effects of environment on voltaic microbatteries, and important reference value for choosing the suitable combination of radioactive source and energy conversion device in special environment. Therefore, it will make the voltaic microbatteries closer to practical application.