Ive hear this one before. Many times. Ive seen examples and heard stories of people using car batteries to charge up their dantian
Luo kanqi comes to mind when car batteries are mentioned, he was seemingly the pioneer in this field
The real question is, is qi just a type of electricity? my thoughts are that it is not, though it appears to take on a form similar to electricity in some cases. Qi appears to be able to take on different forms. In some manifestations it can act like electricity, in other cases like heat, in other cases like a physical force that can move inanimate objects, in still others it can be detected as a sweet taste in the mouth. So no i dont think qi is the same as electricity.
In addition to the guys that charge up their already active dantians with car batteries there seems to be a class of people able to do so without any neigong/qigong training
here is an example of Biba Struja a man who with no previous training was able to train his body to conduct electricity as well as hold an electrical charge and discharge it at a later time.