Method for manufacturing bipolar power storage device

A method for manufacturing a bipolar power storage device, the bipolar power storage device including;

• an electrode stack in which electrodes are stacked, the electrodes including a bipolar electrode that includes a current collector, a positive electrode active material layer on one surface of the current collector, and a negative electrode active material layer on the other surface of the current collector;
• a sealing body provided between the electrodes disposed side by side, the sealing body and the electrodes disposed side by side defining an internal space in which an electrolyte solution is accommodated;
• and
• a liquid injection port formed in the sealing body and providing communication between the internal space and an outside of the bipolar power storage device,
• the method comprising:
• a first depressurizing process in which the internal space is depressurized to a first pressure lower than an atmospheric pressure, through an attachment attached to the liquid injection port;
• a first liquid injecting process, after the first depressurizing process, in which a predetermined amount of the electrolyte solution is injected into the internal space depressurized in the first depressurizing process from a holding member through the liquid injection port by increasing the pressure in the holding member holding the predetermined amount of the electrolyte solution to a pressure higher than the first pressure;
• a second depressurizing process, after the first liquid injecting process, in which a part of the electrolyte solution flows back from the internal space to the holding member through the holding member and the liquid injection port by depressurizing the internal space in which the predetermined amount of the electrolyte solution is injected to a second pressure lower than the atmospheric pressure;
• and
• a second liquid injecting process, after the second depressurizing process, in which the electrolyte solution is injected into the internal space through the liquid injection port from the holding member by increasing the pressure in the holding member holding the electrolyte solution having flowed back in the second depressurizing process to a pressure higher than the second pressure, wherein
• the second depressurizing process includes an initial depressurizing process in which the internal space is depressurized at a depressurizing speed lower than a depressurizing speed in the first depressurizing process.