Inspection method of electrical storage device and manufacturing method thereof

An inspection method of an electrical storage device, the inspection method comprising:

• performing current measurement to acquire a current value after convergence of a current flowing through a circuit formed by connecting an external power source to a charged electrical storage device so that a polarity of a voltage of the external power source is reverse to a polarity of a voltage of the charged electrical storage device, the current measurement being performed after the voltage of the external power source is adjusted so that the current does not flow through the circuit right after the connection;
• and
• performing quality determination to determine quality of the electrical storage device based on the current value after convergence of the current, the current value being acquired by the current measurement, wherein:
• a relationship between a circuit resistance of the circuit and a necessary time for convergence of the current in the current measurement is grasped in advance;
• in the current measurement, resistance measurement to actually measure the circuit resistance of the circuit and prediction to predict a convergence timing of the current based on the actually measured circuit resistance and the relationship are performed;
• and
• after that, without disconnecting the electrical storage device from the external power source in the circuit, the current value is acquired when the predicted convergence timing comes, and the acquired current value is set as the current value after convergence.