BATTERY INTERNAL SHORT-CIRCUIT DETECTING DEVICE AND METHOD, BATTERY PACK, AND ELECTRONIC DEVICE SYSTEM

• US 20100201321A1
• Filed: 07/23/2008
• Published: 08/12/2010
• Est. Priority Date: 07/26/2007
• Status: Abandoned Application

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Fujikawa, Masato, Nakashima, Takuya, Nakatsuji, Toshiyuki, Asakura, Jun
• Application Number:
  US12/670,796
• Publication Number:
  US 20100201321A1
• Time in Patent Office: Days
• US Class Current: 320/132
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 2260/44 by parameter estimation
• CPC Class Codes: B60L 3/0038 relating to sensors
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 3/0069 relating to the isolation, e.g. ground fault or leak current
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 10/448 End of discharge regulating measures
• CPC Class Codes: H01M 10/486 for measuring temperature
• CPC Class Codes: H01M 50/569 Constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals battery terminal connectors with integrated measuring arrangements G01R31/364
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A battery internal short-circuit detecting device has: a battery temperature detection unit for detecting a battery temperature Tr; an ambient temperature detection unit for detecting an ambient temperature Te; an average heating value detection unit for detecting an average value Pav of battery heating values per predetermined first period ΔW1, which are generated by discharging or charging the battery; a battery temperature estimation unit for obtaining a battery temperature Tp estimated to be reached after a lapse of a predetermined second period ΔW2 since the detection of the average value Pav of the heating values, based on the average value Pav of the heating values and the ambient temperature Te; and an internal short-circuit determination unit for determining that an internal short circuit has occurred when the actual battery temperature Tr after the lapse of the second period ΔW2 is equal to or greater than the sum of the estimated battery temperature Tp and a predetermined coefficient α.

Claims

1. A battery internal short-circuit detecting device, comprising:

a battery temperature detection unit for detecting a battery temperature Tr;

an ambient temperature detection unit for detecting an ambient temperature Te;

an average heating value detection unit for detecting an average value Pav of battery heating values per predetermined first period Δ

W1, which are generated by discharging or charging the battery;

a battery temperature estimation unit for obtaining a battery temperature Tp estimated to be reached after a lapse of a predetermined second period Δ

W2 since the detection of the average value Pav of the heating values, based on the average value Pav of the heating values and the ambient temperature Te; and

an internal short-circuit determination unit for determining that an internal short circuit has occurred when an actual battery temperature Tr after the lapse of the second period Δ

W2 is equal to or greater than the sum of the estimated battery temperature Tp and a predetermined coefficient α

.

2. The battery internal short-circuit detecting device according to claim 1, further comprising:

a current detection unit for detecting a current I flowing to the battery; and

an internal resistance acquisition unit for obtaining a battery internal resistance r corresponding to the battery temperature Tr,

wherein the average heating value detection unit calculates a heating value P of the battery a predetermined number of times based on the current I and the internal resistance r during the first period Δ

W1, and obtains the average value of the heating values P as the Pav.

3. The battery internal short-circuit detecting device according to claim 2, further comprising:

a battery state of charge acquisition unit for acquiring the battery state of charge SOC at the start of the first period Δ

W1, thereafter updating the battery state of charge SOC each time the current detection unit detects the current I, and obtaining the battery state of charge SOC at the time of the lapse of the first period Δ

W1;

a terminal voltage estimation unit for obtaining a battery terminal voltage Vp estimated from the battery state of charge SOC obtained at the time of the lapse of the first period Δ

W1;

a terminal voltage detection unit for detecting an actual battery terminal voltage Vr at the time of the lapse of the first period Δ

W1; and

an operation control unit for operating the average heating value detection unit, the battery temperature estimation unit and the internal short-circuit determination unit, only when the actual battery terminal voltage Vr is equal to or lower than a threshold value obtained by adding a predetermined coefficient β

to the terminal voltage Vp.

4. The battery internal short-circuit detecting device according to claim 1, wherein the battery is a nonaqueous electrolyte secondary battery that has a heat-resistant layer between a negative electrode and a positive electrode of the battery, or a nonaqueous electrolyte secondary battery with an electrode plate resistance of at least 4 Ω

·

cm².

5. A battery pack, comprising:

a battery; and

the battery internal short-circuit detecting device described in claim 1.

6. An electronic device system, comprising:

a battery;

a loading device supplied with power from the battery; and

the battery internal short-circuit detecting device described in claim 1.

7. A battery internal short-circuit detecting method, comprising:

a step of detecting a battery temperature Tr;

a step of detecting an ambient temperature Te;

an average heating value detection step of detecting an average value Pav of battery heating values per predetermined first period Δ

W1, which are generated by discharging or charging a battery;

a battery temperature estimation step of obtaining a battery temperature Tp estimated to be reached after a lapse of a predetermined second period Δ

W2 since the detection of the average value Pav of the heating values, based on the average value Pav of the heating values and the ambient temperature Te;

a step of detecting an actual battery temperature Tr after the lapse of the second period Δ

W2; and

an internal short-circuit determination step of determining that an internal short circuit has occurred when the actual battery temperature Tr after the lapse of the second period Δ

W2 is equal to or greater than the sum of the estimated battery temperature Tp and a predetermined coefficient α

.

8. The battery internal short-circuit detecting method according to claim 7, wherein the average heating value detection step has a step of obtaining a current I flowing to the battery, a step of obtaining a battery internal resistance r corresponding to the battery temperature Tr, and a step of calculating a heating value P of the battery a predetermined number of times based on the current I and the internal resistance r during the first period Δ

W1, to obtain the average value of the heating values P as the Pav.

9. The battery internal short-circuit detecting method according to claim 8, further comprising:

a step of acquiring the battery state of charge SOC at the start of the first period Δ

W1;

a step of updating the battery state of charge SOC each time the current detection unit detects the current I, after the step of acquiring the battery state of charge SOC, and then obtaining the battery state of charge SOC at the time of the lapse of the first period Δ

W1;

a step of obtaining a battery terminal voltage Vp estimated from the battery state of charge SOC obtained at the time of the lapse of first period Δ

W1;

a step of detecting an actual battery terminal voltage Vr at the time of the lapse of the first period Δ

W1; and

a step of starting the average heating value detection step, only when the actual battery terminal voltage Vr is equal to or lower than a threshold value obtained by adding a predetermined coefficient β

to the terminal voltage Vp.

10. The battery internal short-circuit detecting method according to claim 7, wherein the battery is a nonaqueous electrolyte secondary battery that has a heat-resistant layer between a negative electrode and a positive electrode of the battery, or a nonaqueous electrolyte secondary battery with an electrode plate resistance of at least 4 Ω

·

cm².