BATTERY CONDITION DETECTOR, BATTERY PACK INCLUDING SAME, AND BATTERY CONDITION DETECTING METHOD

• US 20110187329A1
• Filed: 09/09/2009
• Published: 08/04/2011
• 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: Kitamura, Keiichi, Takeno, Kazuhiko, Uemura, Haruo, Kanai, Yasuyuki, Majima, Yoshihide
• Granted Patent: US 8,749,204 B2
• Time in Patent Office: Days
• 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 remaining capacity calculating part configured to calculate a remaining capacity of a rechargeable battery;

a full-charge capacity calculating part configured to calculate a full-charge capacity of the rechargeable battery;

a micro short circuit determining part configured to determine a micro short circuit of the rechargeable battery by detecting an overcharge of the rechargeable battery based on a charged capacity charged during charging of the rechargeable battery, the remaining capacity calculated at a calculation time immediately before a start of the charging by the remaining capacity calculating part, and the full-charge capacity calculated before the start of the charging by the full-charge capacity calculating part; and

an output part configured to output a signal according to a determination result of the micro short circuit determining part.

2. The battery condition detector as claimed in claim 1, wherein the micro short circuit determining part is configured to determine the micro short circuit of the rechargeable battery if a relational expression represented by (Qrem+Qchg)/Qbat>

K holds, where Qchg is the charged capacity charged during the charging of the rechargeable battery, Qrem is the remaining capacity calculated at the calculation time immediately before the start of the charging by the remaining capacity calculating part, Qbat is the full-charge capacity calculated before the start of the charging by the full-charge capacity calculating part, and K is a positive coefficient greater than or equal to one.

3. The battery condition detector as claimed in claim 1, wherein the output part is configured to output a signal for reporting an abnormality of the rechargeable battery.

4. The battery condition detector as claimed in claim 1, wherein the output part is configured to output a signal for limiting the charging of the rechargeable battery.

12. A battery pack, comprising:

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

the rechargeable battery.

5. A battery condition detector, comprising:

an internal resistance calculating part configured to calculate an internal resistance of a rechargeable battery;

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

an output part configured to output a signal according to a determination result of the micro short circuit determining part.

6. The battery condition detector as claimed in claim 5, wherein the micro short circuit determining part is configured to determine the micro short circuit of the rechargeable battery by detecting the decrease in the internal resistance calculated by the internal resistance calculating part from the initial value of the internal resistance based on the internal resistance calculated by the internal resistance calculating part every time the rechargeable battery is charged.

7. The battery condition detector as claimed in claim 5, wherein the micro short circuit determining part is configured 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 by the internal resistance calculating part.

8. The battery condition detector as claimed in claim 5, wherein the micro short circuit determining part is configured to determine the micro short circuit 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.

9. The battery condition detector as claimed in claim 8, wherein the internal resistance calculating part is configured 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.

10. The battery condition detector as claimed in claim 5, wherein the output part is configured to output a signal for reporting an abnormality of the rechargeable battery.

11. The battery condition detector as claimed in claim 5, wherein the output part is configured to output a signal for limiting charging of the rechargeable battery.

13. A battery pack, comprising:

the battery condition detector as set forth in claim 5; and

the rechargeable battery.

14. A battery condition detecting method, comprising:

determining a micro short circuit of a rechargeable battery by detecting that the rechargeable battery has been charged for a capacity exceeding a chargeable capacity thereof during charging of the rechargeable battery.

15. The battery condition detecting method as claimed in claim 14, comprising:

determining the chargeable capacity of the rechargeable battery by measuring a remaining capacity of the rechargeable battery at a time immediately before a start of the charging of the rechargeable battery and a full-charge capacity of the rechargeable battery immediately before said time.

16. A battery condition detecting method, comprising:

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