Battery pack

• US 8,823,322 B2
• Filed: 10/12/2011
• Issued: 09/02/2014
• Est. Priority Date: 10/15/2010
• Status: Active Grant

• Current Assignee: Makita Corporation
• Original Assignee: Makita Corporation
• Inventors: Noda, Masafumi, Hayashi, Hidekazu, Uesugi, Hiroki
• Primary Examiner(s): DIAO, M BAYE
• Application Number:
  US13/271,516
• Publication Number:
  US 20120096298A1
• Time in Patent Office: 1,056 Days
• Field of Search: 320/116, 320/134, 320/136
• US Class Current: 320/116
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: G01R 31/396 Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/4257 Smart batteries, e.g. electronic circuits inside the housing of the cells or batteries
• CPC Class Codes: H01M 10/441 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/448 End of discharge regulating measures
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/00714 in response to battery charging or discharging current
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: H02J 7/007194 of the battery
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A tool battery pack can include a current detection element for detecting a discharge current or a charge current, a monitoring section for inputting a current signal of the discharge current or the charge current through the current detection element and for inputting voltage signals of each cell battery, and a control microcomputer for performing discharge control or charge control based on the signals from the monitoring section. Further, the tool battery pack is constructed such that the current signal through the current detection element is input to both the monitoring section and the control microcomputer.

Claims

1. A battery pack, comprising:

a secondary cell battery;

a current detection element for detecting a discharge current flowing from the secondary cell battery or a charge current flowing to the secondary cell battery;

a monitoring section for inputting a current signal of the discharge current or the charge current through the current detection element and for inputting a voltage signal of the secondary cell battery; and

a control microcomputer for performing discharge control or charge control based on the signals from the monitoring section, wherein;

the current signal through the current detection element is input to both the monitoring section and the control microcomputer; and

when a first difference between the discharge current signal transmitted from the monitoring section to the control microcomputer and the discharge current signal the control microcomputer acquires from the current detection element exceeds a first defined value, the control microcomputer stores a data showing abnormal discharge current is detected and outputs a signal for stopping discharging;

or

when a second difference between the charge current signal transmitted from the monitoring section to the control microcomputer and the charge current signal the control microcomputer acquires from the current detection element exceeds a second defined value, the control microcomputer stores a data showing abnormal charge current is detected and outputs a signal for stopping charging.

2. The battery pack according to claim 1, wherein a shunt resistance or an FET is used as the current detection element.

3. The battery pack according to claim 1, wherein a System In Package is used as the monitoring section and the control microcomputer.

4. A method for performing discharge control or charge control of a battery pack having a secondary cell battery, comprising the steps of:

detecting a discharge current or a charge current by a current detection element;

inputting a current signal of the discharge current or the charge current through the current detection element to both a monitoring section and a control microcomputer and a voltage signal of the secondary cell battery to the monitoring section;

performing discharge control or charge control based on the signals from the monitoring section by a control microcomputer; and

the step of performing discharge control comprises;

judging whether a first difference between the discharge current signal transmitted from the monitoring section to the control microcomputer and the discharge current signal the control microcomputer acquires from the current detection element exceeds a first defined value;

storing a data showing abnormal discharge current is detected when the first difference exceeds the first defined value; and

outputting a signal for stopping discharging

the step of performing discharge control comprises;

judging whether a second difference between the charge current signal transmitted from the monitoring section to the control microcomputer and the charge current signal the control microcomputer acquires from the current detection element exceeds a second defined value;

storing a data showing abnormal charge current is detected when the second difference exceeds the second defined value; and

outputting a signal for stopping charging.