| 摘要 |
The present invention improves the fuel efficiency of a vehicle by charging and discharging a nickel metal hydride battery, which is connected in parallel, over a wide range of residual capacities, while reducing the deterioration of a lead acid battery by charging and discharging the lead acid battery over a fixed voltage range. A power supply device is provided with: a lead acid battery (1) and a nickel metal hydride battery (2), which supply power to electrical equipment (20) of a vehicle; a main switch (3) connected between the lead acid battery (1) and the electrical equipment (20); a sub-switch (4) connected between the nickel metal hydride battery (2) and the electrical equipment (20); and a control circuit (5) that controls the supply of operating power from the lead acid battery (1) and the nickel metal hydride battery (2) to the electrical equipment (20) of the vehicle. The nickel metal hydride battery (2) is connected to an alternator (23) of the vehicle via the sub-switch (4) and the main switch (3). The control circuit (5) is provided with a residual capacity detection circuit (12) and a switching circuit (11), and, according to the residual capacity of the nickel metal hydride battery (2) detected by the residual capacity detection circuit (12), switches the sub-switch (4) and the main switch (3) on and off via the switching circuit (11). |
