Device body, motor-driven device, and temperature detection method

Patent metadata

Field	Value
Publication number	US-2016359343-A1
Application number	US-201615170488-A
Country	US
Kind code	A1
Filing date	Jun 1, 2016
Priority date	Jun 8, 2015
Publication date	Dec 8, 2016
Grant date	—

Abstract

A device body in one aspect of the present disclosure comprises a motor, a current path, a positive terminal, a negative terminal, a device-side signal terminal, a temperature information detector, a current detector, and a correction unit. The correction unit is configured to correct temperature information based on a current value of a conducting current, so as to reduce an influence given to the temperature information by the conducting current.

First claim

What is claimed is:

1 . A device body comprising:
a motor configured to be driven by electric power supplied from a battery pack, the battery pack comprising a battery, a temperature detector configured to vary a resistance value thereof in accordance with temperature of the battery, a positive electrode, a negative electrode, and a battery-side signal terminal configured to output a temperature signal of which voltage value is changed in accordance with change in the resistance value of the temperature detector; a current path configured to pass a conducting current to the motor therethrough; a positive terminal configured to be coupled to the positive electrode of the battery pack; a negative terminal configured to be coupled to the negative electrode of the battery pack, an electric potential of the negative terminal being set to a reference electric potential of the current path; a device-side signal terminal configured to be coupled to the battery-side signal terminal of the battery pack; a temperature information detector configured to detect temperature information indicating the temperature of the battery based on a temperature detection voltage value, the temperature detection voltage value being a voltage value of the device-side signal terminal with respect to the reference electric potential; a current detector configured to detect a current value of the conducting current; and a correction unit configured to correct the temperature information based on the current value so as to reduce influence given to the temperature information by the conducting current.

2 . The device body according to claim 1 , wherein at least one of the device body and the battery pack comprises a temperature signal generator configured to supply one of current and voltage to the temperature detector.

3 . The device body according to claim 1 , wherein the correction unit is configured to correct the temperature information such that the temperature of the battery indicated by the temperature information becomes lower as the current value increases.

4 . The device body according to claim 1 , further comprising:
a motor control unit configured to drive and control the motor; and an abnormality determination unit configured to determine whether the temperature of the battery is abnormal based on the temperature information and a temperature determination reference value for determining temperature abnormality of the battery.

5 . The device body according to claim 4 , wherein the correction unit is configured to correct the temperature determination reference value based on the current value so as to reduce the influence.

6 . The device body according to claim 5 , wherein the correction unit is configured to correct the temperature determination reference value to be higher as the current value increases.

7 . The device body according to claim 4 , wherein the motor control unit is configured to perform at least one of reduction and suspension of the conducting current to the motor when the temperature of the battery is determined abnormal by the abnormality determination unit.

8 . The device body according to claim 1 , wherein the correction unit is configured to perform a plurality of correction methods as a method of correcting the temperature information, each of the plurality of correction methods corresponding to a mutual different one of a plurality of current regions, the plurality of current regions corresponding to a plurality of ranges that can be taken by the current value.

9 . The device body according to claim 8 , wherein the plurality of current regions comprise 16 or fewer current regions.

10 . A motor-driven device comprising:
a battery pack; and a device body, the battery pack comprising:
a battery;
a temperature detector configured to vary a resistance value according to a temperature of the battery;
a positive electrode;
a negative electrode; and
a battery-side signal terminal configured to output a temperature signal of which voltage value is changed in accordance with change in the resistance value of the temperature detector,
the device body comprising:
a motor configured to be driven by electric power supplied from the battery pack;
a current path configured to pass a conducting current to the motor therethrough;
a positive terminal configured to be coupled to the positive electrode of the battery pack;
a negative terminal configured to be coupled to the negative electrode of the battery pack, an electric potential of the negative terminal being set to a reference electric potential of the current path;
a device-side signal terminal configured to be coupled to the battery-side signal terminal of the battery pack;
a temperature information detector configured to detect temperature information indicating the temperature of the battery based on a temperature detection voltage value, the temperature detection voltage value being a voltage value of the device-side signal terminal with respect to the reference electric potential;
a current detector configured to detect a value of the conducting current; and
a correction unit configured to correct the temperature information based on the current value so as to reduce influence given to the temperature information by the conducting current.

11 . A method of detecting a temperature of a battery that supplies electric power to a motor, the method comprising:
detecting temperature information indicating the temperature of the battery based on a temperature detection value supplied from a temperature detector, the temperature detector being configured such that a resistance value thereof changes in accordance with the temperature of the battery, the temperature detection value changing in accordance with the resistance value; detecting a value of a conducting current to the motor; and correcting the temperature information based on the detected value so as to reduce influence given to the temperature information by the conducting current.

Assignees

• Makita Corp

Inventors

• Ito Takaaki
• Umemura Takuya

Classifications

• H02J7/977

  of the battery · CPC title

• H02J7/855

  with circuits adapted for supplying loads from the battery · CPC title

• H02J7/60 Primary

  including safety or protection arrangements · 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

• G01R31/374

  with means for correcting the measurement for temperature or ageing · CPC title