The present disclosure provides a semiconductor device, a manufacturing method thereof, and a power generating device. The semiconductor device includes a substrate and a thin film battery on the substrate. The thin film battery includes at least one anode structure and at least one cathode structure on the substrate, and a solid electrolyte layer spacing the at least one anode structure apart from the at least one cathode structure. Each anode structure includes an anode current collector on a surface of the substrate and an anode layer on the surface of the substrate and connected to a side surface of the anode current collector. Each cathode structure includes a cathode current collector on the surface of the substrate and a cathode layer on the surface of the substrate and connected to a side surface of the cathode current collector.