Optimization Design and Stability Performance on High-Efficiency Betavoltaic Microbatteries for Space Applications

Due to the characteristics such as long-lifetime, high-energy-density, self-sufficient ability, and amenable-to-miniaturization,betavoltaics possess significant potential for next-generation microbatteries in the low consumption devices for space applications. In this paper,we mainly deal with four things. First,the efficiency limits are discussed. Employing63 Ni and147 Pm with different thicknesses and apparent activity densities,we calculate the total efficiency(ηtotal)and conversion efficiency(η)limits of betavoltaics by MCNP5 and the Schottky equation. Second,the structure parameters are optimized. The structure model of63 Ni-Si betavoltaic in micro-nano scale is established. With the consideration of the isotope self-absorption effect,we optimize the structural parameters of betavotaics,e.g.,the thickness of the source and the thickness,the junction depth,and the doping concentration of the energy conversion unit. Third,several betavoltaic battery samples are prepared. The maximum output power density of the interlayer betavoltaics connected in series or parallel is approximate two times that of the single-layer betavoltaic,which verifies that it is feasible to improve the output performance by using the betavoltaic array in series and parallel. Finally,the effects of the environmental factors,including the vacuum degree and the temperature,on the performance of betavoltaics are studied. The encouraging results present important theoretical foundations and technical supports for the performance evaluation,devices design,performance improvement,and stability study of betavoltaics,and make the betavoltaic microbatteries closer to space applications.