Abstract: A method is for replacing a rechargeable battery that is considered as an unsatisfactory rechargeable battery that needs replacing in an assembled battery in which rechargeable batteries are stacked and restrained in a row and electrically connected in series or in parallel. The method includes removing of finding at least one of the rechargeable batteries to be an unsatisfactory rechargeable battery in the assembled battery and removing the unsatisfactory rechargeable battery, and installing a satisfactory rechargeable battery, which has little deterioration, on at least one end of the row of the rechargeable batteries, in a row direction, in the assembled battery from which the unsatisfactory rechargeable battery has been removed.

Abstract: A rechargeable battery state determination method determines whether a rechargeable battery is in a micro-short-circuit-prone state, which is a state that is highly likely to form a micro-short circuit.

Abstract: A method for determining a state of a rechargeable battery includes obtaining a complex impedance measured by applying AC voltage or AC current to a rechargeable battery that is subject to determination and determining a state of the rechargeable battery based on the obtained complex impedance. The determining a state of the rechargeable battery includes determining whether or not a first capacity shift is occurring based on a comparison of a value of the complex impedance at a predetermined frequency with a first determination value used to determine a negative electrode capacity shift, and when determined that the first capacity shift is not occurring, determining whether or not a second capacity shift is occurring based on a comparison of a gradient of the complex impedance with respect to a real axis in a diffusion resistance region with a second determination value used to determine a positive electrode capacity shift.

Abstract: A method for reusing a vehicle rechargeable battery to rebuild an assembled battery from a plurality of battery units having a usage history is provided. The method includes measuring a remaining charge of each of a plurality of battery units obtained by dismantling an assembled battery having a usage history. The method further includes selecting from the battery units a battery unit in which the measured remaining charge is greater than or equal to a remaining charge lower limit value, which is set in a range that is greater than zero and less than a lower limit value of a remaining charge control range of a vehicle in which the assembled battery was installed, and assembling a new assembled battery using the selected battery unit.

Abstract: A method for determining a state of a rechargeable battery includes obtaining a complex impedance measured by applying AC voltage or AC current to a rechargeable battery that is subject to determination and determining a state of the rechargeable battery based on the obtained complex impedance. The determining a state of the rechargeable battery includes determining whether or not a first capacity shift is occurring based on a comparison of a value of the complex impedance at a predetermined frequency with a first determination value used to determine a negative electrode capacity shift, and when determined that the first capacity shift is not occurring, determining whether or not a second capacity shift is occurring based on a comparison of a gradient of the complex impedance with respect to a real axis in a diffusion resistance region with a second determination value used to determine a positive electrode capacity shift.

Abstract: A method for regenerating a nickel metal hydride battery is provided. The nickel metal hydride battery includes a hydrogen absorbing alloy that serves as a negative electrode material and a safety valve that opens when an internal pressure of a battery case is greater than or equal to a predetermined pressure. The method includes connecting a plurality of nickel metal hydride batteries in parallel. Each nickel metal hydride battery is formed by integrating one or more battery cells. The method further includes overcharging the nickel metal hydride batteries by supplying current from a charge unit that is connected in parallel to the nickel metal hydride batteries. The method further includes, when each nickel metal hydride battery is overcharged, restoring a discharge reserve of a negative electrode by releasing at least some of an oxygen gas generated at a positive electrode out of the battery case through the safety valve.

Abstract: A method for regenerating a nickel metal hydride battery is provided. The nickel metal hydride battery includes a hydrogen absorbing alloy that serves as a negative electrode material and a safety valve that opens when an internal pressure of a battery case is greater than or equal to a predetermined pressure. The method includes connecting a plurality of nickel metal hydride batteries in parallel. Each nickel metal hydride battery is formed by integrating one or more battery cells. The method further includes overcharging the nickel metal hydride batteries by supplying current from a charge unit that is connected in parallel to the nickel metal hydride batteries. The method further includes, when each nickel metal hydride battery is overcharged, restoring a discharge reserve of a negative electrode by releasing at least some of an oxygen gas generated at a positive electrode out of the battery case through the safety valve.

Abstract: A method for reusing a vehicle rechargeable battery to rebuild an assembled battery from a plurality of battery units having a usage history is provided. The method includes measuring a remaining charge of each of a plurality of battery units obtained by dismantling an assembled battery having a usage history. The method further includes selecting from the battery units a battery unit in which the measured remaining charge is greater than or equal to a remaining charge lower limit value, which is set in a range that is greater than zero and less than a lower limit value of a remaining charge control range of a vehicle in which the assembled battery was installed, and assembling a new assembled battery using the selected battery unit.