Nuclear batteries use the incredible amount of energy released naturally by tiny bits of radio active material without any fission or fusion taking place inside the battery. These devices use thin radioactive films that pack in energy at densities thousands of times greater than those of lithium-ion batteries. Because of the high energy density nuclear batteries are extremely small in size. Considering the small size and shape of the battery the scientists who developed that battery fancifully call it as “DAINTIEST DYNAMO”. The word ‘dainty’ means pretty.
The kind of nuclear batteries directly converts the high-energy particles emitted by a radioactive source into an electric current. The device consists of a small quantity of Ni-63 placed near an ordinary silicon p-n junction – a diode, basically.
Scientists have developed two types of micro nuclear batteries. One is junction type battery and the other is self-reciprocating cantilever. The operations of both are explained below one by one.
WORKING
As the Ni-63 decays it emits beta particles, which are high-energy electrons that spontaneously fly out of the radioisotope’s unstable nucleus. The emitted beta particles ionized the diode’s atoms, exciting unpaired electrons and holes that are separated at the vicinity of the p-n interface. These separated electrons and holes streamed away form the junction, producing current.
It has been found that beta particles with energies below 250KeV do not cause substantial damage in Si [4] [5]. The maximum and average energies (66.9KeV and 17.4KeV respectively) of the beta particles emitted by Ni-63 are well below the threshold energy, where damage is observing silicon. The long half-life period (100 years) makes Ni-63 very attractive for remote long life applications such as power of spacecraft instrumentation. In addition, the emitted beta particles of Ni-63 travel a maximum of 21 micrometer in silicon before disintegrating; if the particles were more energetic they would travel longer distances, thus escaping. These entire things make Ni-63 ideally suitable in nuclear batteries
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