| 摘要 |
PROBLEM TO BE SOLVED: To provide a battery pack that makes an user recognize the end of discharge of a secondary battery, and prevents an overdischarge of a battery set to enhance a cycle life characteristics. SOLUTION: A microcomputer 60 is designed to interrupt a connection between a battery set 10 and a power tool 200 when a battery voltage becomes equal to a first predetermined voltage or less, while a load current flows, so that the battery set 10 may not be discharged further; and performs a switching control of the load current flowing through the power tool 200 at a fixed frequency to perform the modulation drive of the motor 210 of the power tool 200, when the battery voltage is between the first predetermined voltage and a second predetermined voltage. Consequently, the user of the power tool 200 is able to sense that the battery set 10 is close to overdischarge, and that the battery set 10 has entered into the overdischarge from the stoppage of rotation of the motor 210. COPYRIGHT: (C)2007,JPO&INPIT |
