Battery control device

A battery control apparatus, comprising:

• a first circuit structured to acquire data indicative of a current flowing in a secondary battery from a current detector;
• a concentration gradient estimator that estimates an ion concentration gradient in a diffusion layer formed around an interface between an electrode and an electrolyte of the secondary battery, based on the current flowing in the secondary battery, or on the current and a temperature of the secondary battery;
• and
• an upper limit current determiner that determines an upper limit current value of the secondary battery, based on the ion concentration gradient,
• wherein the upper limit current determiner determines the upper limit current value such that an overvoltage of the secondary battery according to the ion concentration gradient falls within a predetermined range;
• and
• a second circuit structured to provide an instruction to limit at least one of charging or discharging the secondary battery based on the upper limit current value.