Full charge capacity estimation method and control device

A full charge capacity estimation method for each of a plurality of cells of a bipolar battery, the plurality of cells being stacked in a stack direction, a positive electrode active material of each of the plurality of cells including lithium iron phosphate, the full charge capacity estimation method comprising:

• during charging of the bipolar battery, for each cell of the plurality of cells,
• calculating an increase in a charge amount of the cell when a voltage of the cell increases from a first voltage to a second voltage;
• and
• estimating a full charge capacity of the cell, using the increase in the charge amount, wherein
• the first voltage and the second voltage fall within a predetermined voltage range in which the voltage of the cell increases as a positive electrode potential of the cell increases.