Sealed secondary battery remaining capacity prediction method, remaining capacity prediction system, battery internal information acquisition method, and battery control method

A sealed secondary battery remaining capacity prediction system comprising a detection sensor for detecting deformation of a sealed secondary battery and a controlling device for calculating a predicted value of a remaining capacity of the sealed secondary battery, wherein

• the controlling device is configured to perform:
• detecting deformation of the sealed secondary battery during a charging/discharging cycle C1 before a time point at which the remaining capacity is predicted, so as to determine a first curved line representing a relationship between a charged/discharged capacity and a deformation amount of the sealed secondary battery;
• determining a second curved line by performing a treatment of fitting a reference curved line, which represents a relationship between the charged/discharged capacity and the deformation amount of the sealed secondary battery in a predetermined reference state, to the first curved line;
• detecting a deformation amount Tm of the sealed secondary battery during a charging/discharging cycle C2 after the charging/discharging cycle C1;
• and
• acquiring a charged/discharged capacity Qm corresponding to the deformation amount Tm of the sealed secondary battery on a basis of the second curved line and determining a difference between a charged/discharged capacity Qd in a completely discharged state on the second curved line and the charged/discharged capacity Qm as the remaining capacity.

A sealed secondary battery internal information acquisition method comprising:

• a step of detecting deformation of a sealed secondary battery during a charging/discharging cycle C1 before a time point at which a remaining capacity is predicted, so as to determine a first curved line representing a relationship between a charged/discharged capacity and a deformation amount of the sealed secondary battery;
• a step of determining a second curved line by performing a treatment of fitting a reference curved line, which represents a relationship between the charged/discharged capacity and the deformation amount of the sealed secondary battery in a predetermined reference state, to the first curved line;
• a step of detecting a deformation amount Tm of the sealed secondary battery during a charging/discharging cycle C2 after the charging/discharging cycle C1;
• a step of acquiring a charged/discharged capacity Qm corresponding to the deformation amount Tm of the sealed secondary battery on a basis of the second curved line;
• a step of performing a treatment of fitting, from among a third curved line representing a relationship between a charged/discharged capacity Q and a deformation amount T of a negative electrode acquired from a half cell and a fourth curved line representing a relationship between a negative electrode potential E and a charged/discharged capacity Q of a negative electrode acquired from a half cell, the third curved line to the first curved line, so as to determine a fifth curved line;
• a step of applying a shift amount and an enlargement ratio of the charged/discharged capacity Q, which are used in performing the treatment of fitting the third curved line to the first curved line, to the relationship between the negative electrode potential E and the charged/discharged capacity Q of the fourth curved line, so as to determine a sixth curved line;
• a step of acquiring a negative electrode potential EAm corresponding to the charged/discharged capacity Qm of the sealed secondary battery on a basis of the sixth curved line;
• and
• a step of acquiring a positive electrode potential ECm by subtracting a value of the negative electrode potential EAm from a value of a battery voltage V.