To estimate an internal temperature of a battery in an electric tool device and to prevent the internal temperature from reaching a critical temperature that is an upper limit of an allowable temperature range.
An MCU in a battery pack calculates a temperature elevation amount "Tnow-Tini" of a battery temperature (surface temperature) detected by a thermistor during discharging from a battery as an estimate representing an internal temperature of the battery, restricts discharging control by correcting a threshold value to be used for restriction processing of a discharging current or the like when the temperature elevation amount becomes a determination value "ΔT-x" or higher, and stops discharging when the temperature elevation amount becomes a temperature elevation allowable base value ΔT or higher (S220-S250). Furthermore, minus correction is performed on the temperature elevation allowable base value ΔT so as to reduce the value ΔT as the surface temperature becomes high or as a battery state becomes worse, based on the surface temperature detected by the thermistor, charging history, discharging history, an opening voltage of the battery and remaining capacitance (S180-S210).
OKABAYASHI TOSHIKAZU
KOBAYAKAWA TADAHIKO
| JP2001112185A | 2001-04-20 | |||
| JP2006247821A | 2006-09-21 | |||
| JPH08308139A | 1996-11-22 | |||
| JP2004208349A | 2004-07-22 |