Patent ID: 7164257
Filing Date: 2007-01-16
Classification: B25F,G01R,H01M,H02H,H02J,Y02E

Abstract:
1. A Lithium-ion battery pack configured to be interfaced with a power tool, the battery pack comprising: a housing; a plurality of terminals; a plurality of rechargeable Lithium-ion battery cells arranged within and supported by the housing, each of the battery cells having a respective state of charge, power being transferable between the battery cells and the power tool, the battery cells being operable to collectively supply a discharge current of at least 20 Amperes to power the power tool; a control circuit supported by the housing and operable to control a plurality of functions of the battery pack including discharging functions, the control circuit including a controller and a thermistor, the control circuit configured to monitor the respective state of charge of each of the battery cells, a state of charge of the battery pack, and a battery pack temperature, the control circuit further configured to control at least one function of the battery pack based on the monitored respective states of charge of the battery cells, the monitored state of charge of the battery pack, or the monitored battery pack temperature; a switch configured, when open, to disable transfer of power between the battery cells and the power tool, the switch further configured, when closed, to enable transfer of power between the battery cells and the power tool, the switch including at least one field effect transistor (FET); and a heat sink in heat transfer relationship with the switch and operable to dissipate heat from the switch.