SERVER AND EXTERNAL TERMINAL FOR DETERIORATION DEGREE DETERMINATION SYSTEM FOR SECONDARY BATTERY, AND DETERIORATION DEGREE DETERMINATION SYSTEM

A server for a deterioration degree determination system for a secondary battery includes an estimation formula memory unit and an update unit. The estimation formula memory unit stores an estimation formula for determining a deterioration degree based on a battery characteristic related to transition of a battery state over a predetermined voltage section in the secondary battery or a battery characteristic relationship value related to the battery characteristic. The update unit that updates the estimation formula stored in the estimation formula memory unit based on the battery characteristic related to the transition of the battery state of the secondary battery acquired by charging and discharging the secondary battery in an external terminal.