核电池概述及展望

核电池具有能量密度高、工作稳定可靠、无需人工干预等优点，在需要长期稳定供电的场合具有独特优势，其中热转换式核电池(RTG)是技术最为成熟且应用最早的一类，而β辐射伏特效应核电池已有商业化案例。目前，在β辐射伏特效应核电池研究中存在着放射源自吸收效应浪费能量、转化效率低、换能器件辐射损伤严重等问题，而对于一个实际的核电池，由于放射源自身不断衰变的属性，导致源的成分及其活度随着时间而发生变化，最终影响核电池的电学性能，其影响程度需要加以深入研究。本文以时间轴的形式对核电池的发展进行了全面回顾，简要介绍多种主流类型核电池的原理和应用范围；对于β辐射伏特效应核电池，指出放射源的自吸收是其中的关键科学问题。对于使用63Ni和TiT₂放射源的核电池，给出了其电学性能随时间变化的规律；指出对于某一特定结构的β辐射伏特效应核电池设计，在前期的模拟优化环节中，精细计算是至关重要的；最后提出了将放射源与换能材料相结合、使用含有较重同位素的换能器件的设想，这些设想有利于解决放射源自吸收问题、提高核电池输出功率和减轻辐射损伤的影响。

An Overview and Prospect of Nuclear Battery

The nuclear battery has many advantages, including high energy density, stable performance, no manual intervention etc., which can be widely utilized in cases requiring long-term reliable power supply. Among them, the Radioisotope Thermoelectric Generators (RTG) is the earliest used and the most technically matured one, while betavoltaic battery is now commercialized. However, there are still some problems including self-absorption effect, low energy conversion efficiency and severe radiation damage which restrict the application of betavoltaic batteries. Additionally, for an actual nuclear battery, it should be noticed that the component and density of the source will be changed because the radiation source decays continually, which leads to the electrical performance decline. In this review, the major events in nuclear battery development are listed on a timeline, and the principles and applications of different types of nuclear batteries are also introduced. For betavoltaic battery, the existence of self-absorption effect is pointed out as an important scientific problem, and for batteries with 63Ni and TiT₂ source, the time-related electrical properties are also obtained. This paper also pointed out that, fine and precise calculations are very crucial in the optimized designing processes for a particular structure of the practical nuclear battery. Finally, researching assumptions including combining the source and the energy converting material and the use of energy converting structures with heavier isotopes are presented, which are benefit to solve the self-absorption problem, rise the output power of the nuclear battery and reduce the influence of radiation damage.