Pages: 356-360

Authors: Tom Adams, Shripad T. Revankar, Peter Cabauy, Bret Elkind, and Darrell Cheu

Abstract
Longevity of sensors and portable devices is severely limited by temperature, chemical instability, and electrolyte leakage issues associated with conventional electrochemical batteries. Betavoltaics, which operate similar to photo voltaics, can operate in a wide temperature range safely without permanent degradation. Though not a new concept, which began in the 1950's and peaked in the mid 1970's, research has been minimal and sporadic until recent advancements in ultra-low power electronics and materialization of low power applications. The technology is rapidly maturing, generating research, and development in increasing the beta emitting source and semiconductor efficiencies. This study presents an update on betavoltaic technology, results from temperature evaluation on commercially available General Licensed betavoltaic cells, development of a hybrid system for latent and burst power, modeling and simulation techniques and results, and current and proposed research and development. Betavoltaic performance was successfully demonstrated for a wide temperature range (–30 °C to 70 °C). Short circuit current and open circuit voltage were used to compare electrical performance. Results indicate that the open-circuit voltage and maximum power decreased as temperature increased due to increases in the semiconductor's intrinsic carrier concentration.

Key words: betavoltaic, radioisotope power source, energy harvesting, hybrid battery, solid-state battery, beta emitter, p-n junction, latent power, low power, modelling

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