Power tool and battery pack

Patent metadata

Field	Value
Publication number	US-2017194670-A1
Application number	US-201515315174-A
Country	US
Kind code	A1
Filing date	May 22, 2015
Priority date	May 30, 2014
Publication date	Jul 6, 2017
Grant date	—

Abstract

A power tool includes a motor and control means for controlling the motor. The motor is capable of being driven by power supplied from a battery pack including a battery cell. The control means is configured to continue to rotate the motor even when a motor-halt signal is inputted from the battery pack. With this structure, the power tool can be used continuously without need to halt rotation of the motor, even when receiving a halt signal, such as an overdischarge detection signal or an overcurrent detection signal.

First claim

1 . A power tool comprising:
a motor capable of being driven by power supplied from a battery pack including a battery cell; and
a controller configured to control the motor, and to continue to rotate the motor even when an abnormality signal is inputted from the battery pack.

2 . The power tool according to claim 1 , wherein the controller is further configured to switch a control mode between:
a mode under which the controller halts the motor in response to the abnormality signal; and a mode under which the controller continues to rotate the motor irrespective of the abnormality signal.

3 . The power tool according to claim 1 , wherein the battery pack includes a battery protection portion configured to monitor a state of the battery cell,
wherein the battery protection portion is further configured to output the abnormality signal when current flowing through the battery cell is continuously greater than or equal to a first prescribed value for a first prescribed period of time, and wherein the controller is further configured to halt the motor on the basis of the abnormality signal when temperature of the battery cell is higher than a first predetermined value.

4 . The power tool according to claim 3 , wherein the controller is further configured to:
set an allowable current value and a current flow continuous period when the temperature of the battery cell is lower than the first predetermined value; and in a case where the temperature of the battery cell is low, set the allowable current value to a lower value than that in a case where the temperature of the battery cell is high and further set the current flow continuous period to a longer period than that in a case where the temperature of the battery cell is high, and halt the motor after expiration of the set current flow continuous period.

5 . A power tool comprising:
a motor capable of being driven by power supplied from a battery pack including a battery cell; a battery temperature detector configured to detect temperature of the battery cell; and a controller configured to control the motor, and to continue to rotate the motor in response to a signal outputted from the battery temperature detector even when an abnormality signal is inputted from the battery pack.

6 . The power tool according to claim 5 , wherein the motor is halted in response to the abnormality signal when the temperature of the battery cell is higher than a first predetermined value, whereas the motor continues to rotate irrespective of the abnormality signal when the temperature of the battery cell is lower than or equal to the first predetermined value.

7 . The power tool according to claim 6 , wherein an allowable current value and a current flow continuous period are set when the temperature of the battery cell is lower than the first predetermined value,
wherein in a case where the temperature of the battery cell is low, the allowable current value is set to a lower value than that in a case where the temperature of the battery cell is high and the current flow continuous period is set to a longer period than that in a case where the temperature of the battery cell is high, and wherein the motor is halted after expiration of the set current flow continuous period.

8 . A power tool comprising:
a motor capable of being driven by power supplied from a battery pack including a battery cell; and a controller configured to control the motor, and to switch a control mode between a first mode and a second mode, under the first mode the controller halting the motor when an abnormality signal is inputted from the battery pack, under the second mode the controller continuing to rotate the motor even when the abnormality signal is inputted from the battery pack.

9 . A battery pack connectable to a power tool, the battery pack comprising at least one secondary battery cell, the power tool being capable of continuously performing a desired operation by virtue of discharge current supplied from the secondary battery cell,
wherein when the discharge current becomes large, a period of time during which the desired operation is allowed to be continuously performed is restricted.

10 . The battery pack according to claim 9 , wherein the period of time in a case where temperature of the secondary battery cell is high is shorter than that in a case where the temperature of the secondary battery is low, and
wherein the period of time in a case where the discharge current is large is shorter than that in a case where the discharge current is low.

11 . A battery pack connectable to a power tool, the battery pack comprising at least one secondary battery cell, the power tool being capable of continuously performing a desired operation by virtue of discharge current supplied from the secondary battery cell,
wherein when the discharge current becomes large, a period of time during which the desired operation is allowed to be continuously performed is set, and wherein in a case where temperature of the secondary battery cell is high, the period of time is set to a shorter period than that in a case where the temperature of the secondary battery cell is low.

12 . A power tool to which a battery pack is connectable, the battery pack including at least one secondary battery cell, the power tool being capable of continuously performing a desired operation by virtue of discharge current supplied from the secondary battery cell,
wherein when the discharge current becomes large, a period of time during which the desired operation is allowed to be continuously performed is restricted.

13 . The power tool according to claim 12 , wherein the period of time in a case where temperature of the secondary battery cell is high is shorter than that in a case where the temperature of the secondary battery is low, and
wherein the period of time in a case where the discharge current is large is shorter than that in a case where the discharge current is low.

14 . A power tool to which a battery pack is connectable, the battery pack including at least one secondary battery cell, the power tool being capable of continuously performing a desired operation by virtue of discharge current supplied from the secondary battery cell,
wherein when the discharge current becomes large, a period of time during which the desired operation is allowed to be continuously performed is set, and wherein in a case where temperature of the secondary battery cell is high, the period of time is set to a shorter period than that in a case where the temperature of the secondary battery cell is low.

15 . The power tool according to claim 12 , wherein the power tool comprises:
a motor, and a switching element disposed between the motor and the secondary battery cell and configured to cut off a discharge current path therebetween after the period of time elapses.

Assignees

• Hitachi Koki Kk

Inventors

• Kawano Yoshikazu
• Takano Nobuhiro
• Koizumi Toshiaki
• Funabashi Kazuhiko
• Yoshida Kenichirou
• Aradachi Takao

Classifications

• H02J7/667

  disconnection of loads if battery is not under charge, e.g. in vehicle if engine is not running · CPC title

• H02J7/44

  between battery management systems and power sources · CPC title

• B60L58/10

  for monitoring or controlling batteries · CPC title

• B25F5/00

  Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for · CPC title

• H02J1/002

  using intermediate DC-AC-DC conversion · CPC title