BATTERY SYSTEM

摘要

A battery system includes a chargeable and dischargeable secondary battery and a controller that estimates the deterioration state or the charge state of the secondary battery. When estimating the deterioration state or the charge state, the controller uses an average ion concentration between a positive electrode and a negative electrode. The average ion concentration varies depending on an electric current flowing through the secondary battery. The average ion concentration between the electrodes can be calculated with a computing expression that includes a surface pressure of the secondary battery as a variable. The surface pressure of the secondary battery can be detected by a pressure sensor. The surface pressure of the secondary battery can also be estimated from an electric current flowing through the secondary battery.