It is an atomic energy battery. "Thorium is a radioactive metal element, gray and soft in texture. After neutron bombardment, uranium 233 can be obtained, so it is a potential nuclear fuel." This is the explanation in Baidu Encyclopedia. Nuclear batteries are not new. There used to be Russian Arctic routes.

Many lighthouses that use nuclear batteries have had incidents where loggers accidentally picked up the batteries and were exposed to radiation. Then wtf it’s an electric car.