Battery condition detector, battery pack including same, and battery condition detecting method

• US 8,749,204 B2
• Filed: 09/09/2009
• Issued: 06/10/2014
• Est. Priority Date: 09/11/2008
• Status: Active Grant

• Current Assignee: Mitsumi Electric Co., Ltd. (MinebeaMitsumi Inc.), NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: Mitsumi Electric Co., Ltd. (MinebeaMitsumi Inc.), NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Majima, Yoshihide, Kitamura, Keiichi, Takeno, Kazuhiko, Kanai, Yasuyuki, Uemura, Haruo
• Primary Examiner(s): DIAO, M BAYE
• Application Number:
  US13/062,965
• Publication Number:
  US 20110187329A1
• Time in Patent Office: 1,735 Days
• Field of Search: 320/149, 429/61
• US Class Current: 320/149
• CPC Class Codes: G01R 31/36 Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults
• 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 10/30 Nickel accumulators H01M10/34 takes precedence
• CPC Class Codes: H01M 10/48 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 Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A battery condition detector configured to detect a micro short circuit of a rechargeable battery is disclosed. The battery condition detector includes a processing part configured to calculate the remaining capacity and the full-charge capacity of a rechargeable battery 200 and to determine the micro short circuit of the rechargeable battery 200 by detecting an overcharge of the rechargeable battery 200 based on a charged capacity charged during the charging of the rechargeable battery 200, the remaining capacity calculated at a calculation time immediately before the start of the charging, and the full-charge capacity calculated before the start of the charging; and a communications part 70 configured to output a signal according to the determination result of the processing part 50.

Claims

1. A battery condition detector, comprising:

a processor; and

a memory storing instructions that, when executed by the processor, cause the battery condition detector to

calculate an internal resistance of a rechargeable battery;

determine a micro short circuit of the rechargeable battery by detecting a decrease in the calculated internal resistance from an initial value of the internal resistance; and

output a signal according to a result of determining the micro short circuit.

2. The battery condition detector as claimed in claim 1, wherein the memory stores instructions that, when executed by the processor, cause the battery condition detector to determine the micro short circuit of the rechargeable battery by detecting the decrease in the calculated internal resistance from the initial value of the internal resistance based on the internal resistance calculated every time the rechargeable battery is charged.

3. The battery condition detector as claimed in claim 1, wherein the memory stores instructions that, when executed by the processor, cause the battery condition detector to determine the micro short circuit of the rechargeable battery by detecting a difference exceeding a predetermined determination value, the difference being obtained by subtracting the internal resistance calculated in a current charging cycle from the internal resistance calculated in a previous charging cycle or a charging cycle therebefore.

4. The battery condition detector as claimed in claim 1, wherein the memory stores instructions that, when executed by the processor, cause the battery condition detector to calculate the internal resistance of the rechargeable battery based on a difference in voltage and a difference in current between before and after a start of charging of the rechargeable battery.

5. The battery condition detector as claimed in claim 4, wherein the memory stores instructions that, when executed by the processor, cause the battery condition detector to calculate the internal resistance based on:

the difference in voltage between a first voltage detected at a detection time before detection of a value of a charging current of the rechargeable battery greater than or equal to a predetermined value and a second voltage detected at a detection time after the detection of the value of the charging current greater than or equal to the predetermined value; and

the difference in current between a first current detected at the detection time before the detection of the value of the charging current of the rechargeable battery greater than or equal to the predetermined value and a second current detected at the detection time after the detection of the value of the charging current greater than or equal to the predetermined value.

6. The battery condition detector as claimed in claim 1, wherein the memory stores instructions that, when executed by the processor, cause the battery condition detector to output a signal for reporting an abnormality of the rechargeable battery.

7. The battery condition detector as claimed in claim 1, wherein the memory stores instructions that, when executed by the processor, cause the battery condition detector to output a signal for limiting charging of the rechargeable battery.

8. A battery pack, comprising:

the battery condition detector as set forth in claim 1; and

the rechargeable battery.

9. A battery condition detecting method, comprising:

calculating an internal resistance of a rechargeable battery;

determining a micro short circuit of the rechargeable battery by detecting a decrease in the calculated internal resistance of the rechargeable battery from an initial value of the internal resistance; and

outputting a signal according to a result of determining the micro short circuit.