Battery charger and control method thereof

Patent metadata

Field	Value
Publication number	US-10291044-B2
Application number	US-201615175509-A
Country	US
Kind code	B2
Filing date	Jun 7, 2016
Priority date	Jun 8, 2015
Publication date	May 14, 2019
Grant date	May 14, 2019

Abstract

A battery charger in one aspect of the present disclosure includes an attachment portion, a charging circuit, a positive electrode terminal, a negative electrode terminal, at least one signal input terminal, an analog value acquisition device, a charging current detector, a comparison processor, and a current value reflection processor. The current value reflection processor performs one of a variable determination process for reference values and an analog value correction process. The variable determination process is a process for the current value reflection processor to variably determine the reference value based on a value of a charging current detected by the charging current detector. The analog value correction process is a process for the current value reflection processor to correct an analog value to be used in a comparison by the comparison processor based on the value of the charging current detected by the charging current detector.

First claim

What is claimed is:

1. A battery charger comprising:
an attachment portion configured such that a battery pack is to be detachably attached, the battery pack comprising: a battery having a positive electrode and a negative electrode; and at least one signal output terminal, the at least one signal output terminal being configured to output an analog signal with an analog value;
a charging circuit configured to generate charging current for charging the battery;
a positive electrode terminal configured to be electrically coupled to the positive electrode of the battery in the battery pack when the battery pack is attached to the attachment portion and to output the charging current generated in the charging circuit to the positive electrode;
a negative electrode terminal configured to be electrically coupled to the negative electrode of the battery in the battery pack when the battery pack is attached to the attachment portion and to receive the charging current generated in the charging circuit from the negative electrode, an electric potential of the negative electrode terminal being set to a reference potential of the charging circuit;
at least one signal input terminal configured to be electrically coupled to the at least one signal output terminal in the battery pack when the battery pack is attached to the attachment portion, wherein the at least one signal input terminal receives the analog signal from the at least one signal output terminal in the battery pack;
an analog value acquisition device configured to acquire the analog value of the analog signal inputted to the at least one signal input terminal, the analog value obtained by the analog value acquisition device corresponding to a voltage value of the analog signal with respect to the reference potential;
a charging current detector configured to detect a value of the charging current;
a comparison processor configured to make comparison of a target comparison value based on the analog value obtained by the analog value acquisition device with a predetermined reference value determined in the battery charger and to perform a predetermined process based on a result of the comparison;
a current value reflection processor configured to perform a variable determination process for reference values, the variable determination process for reference values being a process for the current value reflection processor to set the predetermined reference value based on the value of the charging current detected by the charging current detector.

2. The battery charger according to claim 1 ,
wherein the analog value of the analog signal indicates an internal state of the battery pack.

3. The battery charger according to claim 1 ,
wherein the current value reflection processor is configured to set the predetermined reference value in the variable determination process for reference values such that the predetermined reference value increases with the value of the charging current detected by the charging current detector.

4. The battery charger according to claim 1 ,
wherein the battery comprises a plurality of cells,
wherein the at least one signal output terminal comprises at least one cell voltage output terminal configured to output cell voltage signal, the cell voltage signal being an analog signal having an analog value that corresponds to a voltage value of one of the plurality of cells,
wherein the at least one signal input terminal comprises at least one cell voltage input terminal configured to be electrically coupled to the at least one cell voltage output terminal when the battery pack is attached to the battery charger,
wherein the at least one cell voltage input terminal receives the cell voltage signal from the at least one cell voltage output terminal, and
wherein the analog value acquisition device is configured to acquire at least the analog value of the cell voltage signal inputted to the at least one cell voltage input terminal.

5. The battery charger according to claim 1 ,
wherein the battery pack comprises a temperature detector configured to output voltage corresponding to temperature of the battery,
wherein the at least one signal output terminal comprises a temperature signal output terminal configured to output a temperature signal, the temperature signal being an analog signal having an analog value corresponding to the voltage outputted from the temperature detector,
wherein the at least one signal input terminal comprises a temperature signal input terminal configured to be electrically coupled to the temperature signal output terminal when the battery pack is attached to the battery charger,
wherein the temperature signal input terminal receives the temperature signal from the temperature signal output terminal, and
wherein the analog value acquisition device is configured to acquire at least the analog value of the temperature signal inputted to the temperature signal input terminal.

6. The battery charger according to claim 1 ,
wherein the analog value acquisition device is configured to acquire an analog value corresponding to a voltage of the battery inputted from the battery pack to the positive electrode terminal.

7. The battery charger according to claim 1 ,
wherein the comparison processor is configured to determine, upon performing the predetermined process, whether abnormality has occurred in the battery pack based on the result of the comparison while the charging current is outputted to the battery pack.

8. The battery charger according to claim 7 ,
wherein the comparison processor is configured to perform, upon occurrence of the abnormality in the battery pack being determined, a process to stop output of the charging current from the charging circuit to the battery pack.

9. A control method of a battery charger comprising:
inputting at least one analog signal from a battery pack to a battery charger, the battery pack comprising a positive electrode, a negative electrode, and at least one analog signal output terminal, the at least one analog signal having an analog value and being inputted to the battery charger through the at least one analog signal output terminal in the battery pack;
acquiring the analog value of the at least one analog signal, the analog value corresponding to a voltage value of the at least one analog signal with respect to a reference potential of the battery charger;
outputting a charging current from the battery charger to the battery pack, the charging current fluctuating the voltage value of the at least one analog signal with respect to the reference potential;
detecting a value of the charging current;
comparing a comparison target value based on the acquired analog value with a predetermined reference value;
performing a predetermined process based on a result of the comparing of the comparison target value with the predetermined reference value; and
performing one of a variable determination process for reference values and an analog value correction process, the variable determination process for reference values being a process to set the predetermined reference value based on the value of the detected charging current, the analog value correction process being a process to correct the analog value to be used in the comparing based on the detected value of the charging current.

10. A battery charger comprising:
an attachment portion configured such that a battery pack is to be detachably attached, the battery pack comprising: a battery having a positive electrode and a negative electrode; and at least one signal output terminal, the at least one signal output terminal being configured to output an analog signal with an analog value;
a charging circuit con

Assignees

• Makita Corp

Inventors

• Uesugi Hiroki

Classifications

• H02J7/96

  in response to battery voltage · CPC title

• H02J7/94

  in response to battery current · CPC title

• H02J7/977

  of the battery · CPC title

• H02J7/485

  with provisions for charging different types of batteries · CPC title

• H02J7/65

  against overtemperature · CPC title