Battery pack, charging system, and method for charging battery pack

Patent metadata

Field	Value
Publication number	US-12580236-B2
Application number	US-202117906066-A
Country	US
Kind code	B2
Filing date	Feb 4, 2021
Priority date	Mar 17, 2020
Publication date	Mar 17, 2026
Grant date	Mar 17, 2026

Abstract

A battery pack is provided in which the battery pack itself can recognize a determination of a full charge, which is made by a charger, without using a communication line. A battery pack is provided with a secondary battery, current measurement means for measuring a charging current for charging the secondary battery, and a control circuit which receives an output signal from the current measurement means. The control circuit determines that the secondary battery is fully charged when a reduction rate of the charging current in a unit time exceeds a predetermined value.

First claim

The invention claimed is:

1 . A battery pack comprising:
a secondary battery; current measurement means for measuring a charging current for charging the secondary battery; and a control circuit that receives an output signal from the current measurement means, wherein the control circuit determines that the secondary battery is fully charged when a reduction rate of the charging current in a unit time exceeds a predetermined value.

2 . The battery pack according to claim 1 , wherein:
the charging current includes a rapid charging current for increasing a battery capacity of the secondary battery and a supplementary charging current for maintaining a full charge of the secondary battery; and wherein: the reduction rate of the charging current in the unit time corresponds to a change rate of the charging current when the charging current is switched from the rapid charging current to the supplementary charging current.

3 . The battery pack according to claim 2 , wherein:
the rapid charging current includes a pulse current having a first duty ratio; the supplementary charging current includes a pulse current having a second duty ratio shorter than the first duty ratio; and the control circuit determines that the battery pack is fully charged when a duty ratio of the charging current is switched from the first duty ratio to the second duty ratio.

4 . The battery pack according to claim 3 , further comprising indication means for indicating a charge state of the secondary battery,
wherein the control circuit causes the indication means to indicate a full charge state of the secondary battery when the control circuit determines that the secondary battery is fully charged.

5 . The battery pack according to claim 2 , further comprising indication means for indicating a charge state of the secondary battery,
wherein the control circuit causes the indication means to indicate a full charge state of the secondary battery when the control circuit determines that the secondary battery is fully charged.

6 . The battery pack according to claim 1 , further comprising indication means for indicating a charge state of the secondary battery,
wherein the control circuit causes the indication means to indicate a full charge state of the secondary battery when the control circuit determines that the secondary battery is fully charged.

7 . A method for charging a battery pack provided with a secondary battery, current measurement means for measuring a charging current for charging the secondary battery, and a control circuit which receives an output signal of the current measurement means, the method comprising:
determining, by the control circuit, that the secondary battery is fully charged when a reduction rate of the charging current in a unit time exceeds a predetermined value.

8 . The method according to claim 7 , wherein the battery pack is further provided with indication means for indicating a charge state of the secondary battery; and wherein the control circuit causes the indication means to indicate a full charge state of the secondary battery when the control circuit determines that the secondary battery is fully charged.

Assignees

• Fdk Corp

Inventors

• Mizoguchi Yasunari
• Kusagaya Yusuke

Classifications

• H02J7/947

  in response to integrated charge or discharge current · CPC title

• H02J7/927

  with introduction of pulses during the charging process · CPC title

• H01M2010/4271

  Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing · CPC title

• H01M10/48

  Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte (constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569) · CPC title

• H01M10/46

  Accumulators structurally combined with charging apparatus (circuits for charging H02J7/00) · CPC title