Power storage device and electronic device

Abstract

A power storage device or the like with low power consumption is provided. Alternatively, a power storage device or the like with high integration is provided. A first battery cell includes a first electrode over a first substrate, a positive electrode active material layer over the first electrode, an electrolyte layer over the positive electrode active material layer, a negative electrode active material layer over the electrolyte layer, and a second electrode over the negative electrode active material layer. The comparison circuit includes a first input terminal, a second input terminal, an output terminal, and a first transistor. The first transistor includes an oxide semiconductor over the first substrate, a first insulator over the oxide semiconductor, and a gate electrode over the first insulator. The first electrode is electrically connected to the gate of the first transistor and the first input terminal. The comparison circuit has a function of outputting a first signal in response to a result of comparison between a potential of the first electrode and a desired reference potential from the output terminal to the control circuit. The control circuit has a function of controlling charging of the first battery cell in accordance with the first signal.