| 摘要 |
PROBLEM TO BE SOLVED: To provide a battery pack which notifies a user of the final discharging of a secondary battery, prevent over-discharging of a battery set, and improve cycle life characteristics of the batteries. SOLUTION: A microcomputer 60 disconnects a battery set 10 and a power tool 200 if a battery voltage becomes lower than a first prescribed voltage when a load current is flowing, and prevents further discharging of the battery set 10. When a battery voltage is higher than the first prescribed voltage and lower than a second prescribed voltage, the microcomputer 60 controls at a fixed frequency the load current flowing into the power tool 200 by switching, and drives a motor 210 of the power tool 200 by in different modes. By these operations, a user of the power tool 200 can perceive that the battery set 10 is almost over-discharging, or that the battery set 10 has entered the state of over-discharging because revolution of the motor 210 stops. COPYRIGHT: (C)2003,JPO |
