Honeycomb Betavoltaic Battery for Space Applications

Abstract

Radioisotopic batteries offer advantages relative to conventional chemical batteries for applications requiring a long lifetime with minimum maintenance. Thus, thermoelectric type cells fueled with Pu have been used extensively on NASA space missions. The design for a small beta battery using nickel-63 (Ni-63) and a vacuum direct collection method is described here. A honeycomb nickel wire structure is employed to achieve bi-directional direct collection by seeding Ni-63 onto honeycomb shaped wires that will provide structural support as well. The battery design is intended to power low power electronics and distribute power needs in space probes as well as space colonies. Ni-63 is chosen as the source emitter because it has a long half-life and ease of manufacturing. The use of vacuum is especially well mated to space use; hence, vacuum insulation is employed to gain a higher efficiency than prior beta batteries with a dielectric insulator. A unique voltage down-converter is incorporated to efficiently reduce the inherent output voltage from 17.4 kV to ~ 17.4 V. This converter operates like a "reverse" Marx circuit where capacitor charging occurs in series but the discharge is in parallel. The reference battery module described here is about 100 cm x 100 cm x 218 cm and has a power of ~10 W with a conversion efficiency of-15.8 %. These modules can be stacked for higher powers and are very attractive for various applications in space colonization due to their long life (half-life for Ni-63 -100 yrs) and low maintenance.

A betavoltaic microcell based on Au/s-SWCNTs/Ti Schottky junction

“…It might become an alternative of widely used solar cell in many areas, such as wireless sensor nodes [1,2], astronautics [3] and so on. Similar to well-known photovoltaic effect which is the foundation of solar cells, the electron voltaic effect [4] discovered in 1951 brought us a new manner of energy conversion directly from radiation energy to electricity.…”