Patent ID: 8742724
Filing Date: 2014-06-03
Classification: B25F,H01M,H02J,Y02E

Abstract:
1. A battery pack for power tool comprising: a battery that includes at least one battery cell; a monitoring circuit that monitors a status of the battery, the monitoring circuit being operated by receiving power supply from the battery; a sleep mode switching unit that switches the battery pack to a sleep mode by stopping at least a part or all of operations of the monitoring circuit if the monitoring circuit detects a discharge end state where a discharge current from the battery is equal to or lower than a predetermined set current value, and the monitoring circuit further detects at least one of a voltage stable state where a voltage change amount in the battery cell is within a predetermined stable range of voltage change amount and a temperature stable state where a temperature change amount in the battery is within a predetermined stable range of temperature change amount, wherein in a normal operational state of the monitoring circuit, the monitoring circuit detects an abnormality of the batter cell if a temperature change amount in the batter cell is equal to or greater than a redetermined value or if the voltage change amount in the batter cell is equal to or greater than a predetermined value.