原子能电池（又称核电池，氚电池或放射性同位素发电装置）是指那些使用放射性同位素衰变时产生之能量来产生电力的装置。这会使人误解成核反应堆，但实际上这种电池不是利用链式反应来产生能量。核电池比起一般电池有很长的寿命且其输出能量远比一般化学电池为高，可惜其制作成本也相对很高，使这种电池多用于一些需长时间运作又难以更换电池的仪器之上。

核电池之技术早在1913年已经被亨利·莫塞莱所发明，使众科学家都期望此技术能够用于太空仪器上。但由于一直无法提高能源效率，这技术到近年奈米技术研发出更有效之半导体后再被关注。

The terms atomic battery, nuclear battery, tritium battery and radioisotope generator are used to describe a device which uses energy from the decay of a radioactive isotope to generate electricity. Like nuclear reactors they generate electricity from atomic energy, but differ in that they do not use a chain reaction. Compared to other batteries they are very costly, but have extremely long life and high energy density, and so they are mainly used as power sources for equipment that must operate unattended for long periods of time, such as spacecraft, pacemakers, underwater systems and automated scientific stations in remote parts of the world.