A device which uses energy from the decay of a radioactive isotope to generate electricity is referred to as an atomic battery, nuclear battery, radioisotope battery or radioisotope generator. They are not nuclear reactors because although they generate electricity from nuclear energy, they differ in that they do not use a chain reaction. Although they are commonly called batteries, they are technically not electrochemical and cannot be charged or recharged. They were very expensive but have an extremely long life and high energy density. They are typically used as power sources for equipment that must operate unattended for long periods of time. Nuclear battery technology development began in 1913. There was a great deal of research for space applications in the 1950s and 1960s.
There are two types of nuclear batteries. The first type is called a radioisotope thermoelectric generator. These batteries convert some of the heat from radioactive decay to electricity. Scientists in the Soviet Union and United States developed the technology for use in spacecraft, underwater systems and remote scientific stations. However, these thermonuclear batteries were both costly and bulky.
The second type of nuclear battery is a non-thermal converter that extracts electricity directly from emitted radiation. They are easier to miniaturize and so are applicable to small-scale applications. A popular version is called a betavoltaic battery. Betavoltaic batteries have an efficiency as high as eight percent. City Labs is currently selling a tiny tritium-based betavoltaic.
A Chinese startup has announced a new nuclear battery that it claims can generate electricity for 50 years without the need for charging or maintenance. Beijing-based Betavolt claims that its nuclear battery is one of the first in the world to realize the miniaturization of atomic energy, placing nuclear isotopes into a module smaller than a coin. The company said its next-generation battery had already entered the pilot testing stage. It will eventually be mass produced for commercial applications like phones and drones.
The company said in a press release that “Betavolt atomic energy batteries can meet the needs of long-lasting power supply in multiple scenarios, such as aerospace, AI equipment, medical equipment, microprocessors, advanced sensors, small drones and micro-robots. This new energy innovation will help China gain a leading edge in the new round of the AI technological revolution.”
The quest to miniaturize and commercialize nuclear batteries was taken up under China’s 14th Five-Year Plan designed to strengthen the country’s economy between 2021 and 2025. Research institutions in the US and Europe have also been working on their development.
Betavolt said its first nuclear battery can supply one hundred microwatts of power and at a voltage of 3V. It measures 15x15x5 cubic millimeters. Betavolt plans to produce a battery with 1 watt of power by 2025. The small size of the battery indicates that it could be used in series to produce more power. The company envisions mobile phones that never need to be charged and drones that can fly forever. The layered design also means that the battery will not catch fire or explode in response to sudden force. It is also capable of working in temperatures ranging from -60C to 120C. The radioactive isotope in the battery is Nickel-63.
The company said, “The atomic energy battery developed by Betavolt is absolutely safe, has no external radiation, and is suitable for use in medical devices such as pacemakers, artificial hearts and cochleas in the human body. Atomic energy batteries are environmentally friendly. Following the decay period, the isotopes turn into a stable isotope of copper, which is non-radioactive and does not pose any threat or pollution to the environment.