Abstract: This power supply device includes a battery unit which includes: a first battery pack; a step-up/down circuit for boosting the voltage of an external power supply up to the charge voltage of the battery pack; a first charge circuit; a first discharge circuit for detecting a voltage drop of the external power supply and performing discharge from the battery pack to a load device; and a control circuit for controlling charging and discharging. The discharge circuit has a first discharge switch and a second discharge switch which are connected in series between the battery pack and a power supply line. The first discharge switch is switched on/off by receiving a switching signal from the control circuit, and the second discharge switch is directly switched on/off not via the control circuit on the basis of the voltage of the external power supply.

Abstract: Provided is a backup power supply that efficiently supplies power under the control of a microcomputer. The backup power supply is charged by a rectifier for generating power of a predetermined voltage, and supplies power to a load device operating with power supplied from the rectifier when the supplied power is insufficient. The backup power supply includes a secondary battery to be charged with power from the rectifier, a control unit for controlling charging and discharging of the secondary battery, and an input/output voltage detection unit for detecting the output voltage from the rectifier. The control unit stops charging of the secondary battery or reduces a charging current flow of the secondary battery when the output voltage drops to a first threshold voltage or less.

Abstract: A battery bank unit includes: a first battery bank and a second battery bank that are connected in parallel to each other; and a control apparatus that performs collective charge for collectively charging the first battery bank and the second battery bank, performs first bank charge for charging only the first battery bank after the collective charge, and performs second bank charge for charging only the second battery bank after the first bank charge. The control apparatus calculates remaining time to complete charge of the battery bank unit based on a temperature of the battery bank unit at a start of the collective charge.

Abstract: [Object] There is provided series-connected rechargeable cells in which a large number of cells are series-connected and that makes it possible to improve performance on operations such as assembly or exchange and to perform speedy and smooth voltage-balance correcting for all cells. [Means for Solution] Series-connected rechargeable cells includes: a large number of rechargeable cells that are series-connected, and that are divided into a plurality of series-connected cell groups placed continuously in order of connecting; and a voltage-balance correcting circuit that balances the voltages of the cells, and that is provided with an inter-cell voltage-balance correcting circuit that performs voltage-balance correcting between adjacent cells in each of the cell groups and an inter-group voltage-balance correcting circuit that performs balance correcting of series-connection voltages of the cell groups by AC-coupling formed with a transformer coil and a switching circuit.

Abstract: [Object] There is provided series-connected rechargeable cells in which a large number of cells are series-connected and that makes it possible to improve performance on operations such as assembly or exchange and to perform speedy and smooth voltage-balance correcting for all cells. [Means for Solution] Series-connected rechargeable cells includes: a large number of rechargeable cells that are series-connected, and that are divided into a plurality of series-connected cell groups placed continuously in order of connecting; and a voltage-balance correcting circuit that balances the voltages of the cells, and that is provided with an inter-cell voltage-balance correcting circuit that performs voltage-balance correcting between adjacent cells in each of the cell groups and an inter-group voltage-balance correcting circuit that performs balance correcting of series-connection voltages of the cell groups by AC-coupling formed with a transformer coil and a switching circuit.