An atomic battery derives power to run a device from the breakdown of radioactive isotopes. These batteries can have an extremely long life, which makes them useful for applications where it is difficult or impossible to access components for the purpose of battery replacement. They are sometimes referred to as “nuclear batteries,” although this is a bit of a misnomer, as they do not rely on a chain reaction to generate energy. They are very stable and safe when constructed properly and made with appropriate isotopes.
One application for atomic batteries is used in powering spacecraft. Probes, telescopes, and other equipment all need a source of power, but may not be serviceable to replace batteries. An atomic battery can provide the energy needed to keep systems running and send signals back to base, and should last for the life of the device. Other equipment that needs to be left unattended for extended periods of time can rely on this technology, which also has potential applications for things like implanted medical devices.
These batteries can extract energy from radioactive isotopes in a number of ways. Some rely on thermal energy. As isotopes break down, they produce heat, which an atomic battery can harness to make electricity. The heat can also be useful on devices like spacecraft, which need a source of warmth to keep scientific instruments in a safe temperature range. In the deep cold of space, components would quickly freeze without heating, but expending energy on heat could cause the equipment to run out of power, so atomic batteries provide both heat and power to resolve this problem.
Other devices rely on non-thermal methods of energy generation. The most common method takes advantage of beta particle emission to create electricity. This atomic battery design is known as a betavoltaic design, and is quite safe for use around people, because beta particles cannot penetrate human skin. They are much weaker than the more dangerous gamma particles that can be a concern with some radioactive isotopes.
It is also potentially possible to convert the decay directly into kinetic energy for use to move mechanical components of a device. Experimental atomic battery projects have shown how this application could be useful for some medical devices and other equipment. The life of the battery depends on the characteristics of the isotope used to make it, but could be a decade or more. This can meet the needs of many devices, providing a stable energy supply for an extended period of time.