Abstract: An appropriate upper limit current value is set in consideration of steep change in battery voltage in a high-current region caused by the ion concentration gradient in a diffusion layer formed around an interface between an electrode and an electrolyte. An upper limit current calculator 152 includes: a concentration gradient estimator 1523 that estimates a lithium ion concentration gradient in a diffusion layer formed around an interface between an electrode and an electrolyte of a battery, based on a current flowing in the battery, or on the current and a temperature; and an upper limit current determiner 1524 that determines an upper limit current value of the battery, based on the lithium ion concentration gradient. The upper limit current determiner 1524 determines the upper limit current value such that an overvoltage of the battery according to the lithium ion concentration gradient falls within a predetermined range.

Abstract: A control apparatus controls a charging device that is connected to a secondary battery having a negative electrode which is a mixture of graphite and silicon monoxide and supplies a current to the secondary battery, wherein when a calculated SOC (State of Charge) of the secondary battery is less than 15%, a magnitude of the current supplied to the secondary battery by the charging device is controlled to a first value, and when the calculated SOC of the secondary battery is equal to or more than 15%, the magnitude of the current supplied to the secondary battery by the charging device is controlled to a second value that is larger than the first value.

Abstract: An appropriate upper limit current value is set in consideration of steep change in battery voltage in a high-current region caused by the ion concentration gradient in a diffusion layer formed around an interface between an electrode and an electrolyte. An upper limit current calculator 152 includes: a concentration gradient estimator 1523 that estimates a lithium ion concentration gradient in a diffusion layer formed around an interface between an electrode and an electrolyte of a battery, based on a current flowing in the battery, or on the current and a temperature; and an upper limit current determiner 1524 that determines an upper limit current value of the battery, based on the lithium ion concentration gradient. The upper limit current determiner 1524 determines the upper limit current value such that an overvoltage of the battery according to the lithium ion concentration gradient falls within a predetermined range.

Abstract: A square secondary battery suppresses welding failure from occurring by temporarily retaining and securing a sealing cover and enabling detection by a leakage test even when welding failure occurs. The square secondary battery has a case surface portion with an injection opening for injecting an electrolyte, a sealing cover disposed at a position opposite to the case surface portion and sealing the injection opening and having an outer edge welded to the case surface portion to seal the injection opening, and a pressure sensitive adhesive member interposed between the sealing cover and the case surface portion for securing the sealing cover to the case surface portion. A gas passage is provided between the case surface portion and the sealing cover for communicating a gap formed at a position outer to the pressure sensitive adhesive member with respect to a battery case and the injection opening in a ventilation manner.

Abstract: A square secondary battery suppresses welding failure from occurring by temporarily retaining and securing a sealing cover and enabling detection by a leakage test even when welding failure occurs. The square secondary battery has a case surface portion with an injection opening for injecting an electrolyte, a sealing cover disposed at a position opposite to the case surface portion and sealing the injection opening and having an outer edge welded to the case surface portion to seal the injection opening, and a pressure sensitive adhesive member interposed between the sealing cover and the case surface portion for securing the sealing cover to the case surface portion. A gas passage is provided between the case surface portion and the sealing cover for communicating a gap formed at a position outer to the pressure sensitive adhesive member with respect to a battery case and the injection opening in a ventilation manner.