EP-3293533-B1 - APPARATUS AND METHOD FOR DETECTING BATTERY CELL FAILURE DUE TO UNKNOWN DISCHARGE CURRENT

Inventors

• KOO, JIN SAM
• JEON, KWANG SOO
• PACK, Jun Hyuk
• LEE, DONG HYUN
• KWON, KYOUNG MIN
• LEE, JONG HWA

Dates

Publication Date

20260513

Application Date

20161123

Claims (5)

1. A method for detecting failure of a battery cell due to an unknown discharge current, the method comprising: a detector connection operation (S610) of connecting a detector (100) in series between the battery cell (200) and a power supply (300) for supplying a charging power; a test proper charging time determination operation (S620) of determining whether the charging of the battery cell (200) progresses by the charging power in excess of a predetermined battery cell specific charging reference time; a current real-time measurement operation (S630) of measuring a current value of the battery cell (200) in real time a battery cell current accumulation storage operation (S640) of accumulating and storing the real-time measured current value of the battery cell (200) in a storage element (120) for each measured time; a current slope variation calculation operation (S650) of calculating a current slope variation of the current value of the battery cell accumulated and stored in the battery cell accumulation storage operation; an unknown discharge current monitoring operation (S660) of determining whether the current slope variation calculated in the current slope variation calculation operation exceeds a predetermined battery cell specific failure determination reference current slope variation value; and a failure detection completion operation (S670) of determining a state of the battery cell as a failure state in which an unknown discharge occurs if the current slope variation value exceeds the predetermined battery cell specific failure determination reference current slope variation value, wherein the charging is a constant voltage charging, characterized in that : the current real-time measurement operation (S630) of measuring a current value of the battery cell (200) in real time is performed only if the charging of the battery cell progresses in excess of the battery cell specific charging reference time.
2. The method of claim 1, wherein the failure detection completion operation further comprises a failure detection notification operation of expressing the failure state through at least one of a speaker (130), a display unit (140), and a lamp (150).
3. An apparatus (100), which is connected in series between the battery cell (200) and a power supply (300) for supplying charging power, for detecting failure of a battery cell due to an unknown discharge current, the apparatus comprising: a storage element (120) configured to store a battery cell specific failure determination reference current variation value and a battery cell specific charging reference time in advance; a current measurement unit (110) configured to measure a real-time current from the battery cell; and a control unit (160) configured to determine whether the charging of the battery cell progresses in excess of the battery cell specific charging reference time by the charging power, accumulate and store the current value of the battery cell measured in real time in the current measurement unit in the storage element for each measure time calculate a current slope variation of the accumulated and stored current value of the battery cell, determine whether the calculated current slope variation exceeds the battery cell specific failure determination reference current variation value, and determine a state of the battery cell as a failure state in which an un unknown discharge failure occurs if the current slope variation value exceeds a predetermined battery cell specific failure determination reference current slope variation value, characterized in that the control unit (160) is configured to accumulate and store the current value of the battery cell measured in real time in the current measurement unit in the storage element for each measure time only if the charging of the battery cell progressed in excess of the battery cell specific charging reference time.
4. The apparatus of claim 3, wherein the control unit (160) further comprises: a test proper charging time determination unit (161) configured to determine whether the charging of the battery cell progresses in excess of the battery cell specific charging reference time; and a battery cell current accumulation storage unit (164) configured to accumulate and store a current value of the battery cell measured in real time in the current measurement unit in the storage element for each measured time if the charging of the battery cell progresses in excess of the battery cell specific charging reference time; a current slope variation calculation unit (165) configured to calculate the current slope variation from the accumulated and stored current value of the battery cell; and a current slope determination unit (166) configured to determine whether the calculated current slope variation exceeds the battery cell specific failure determination reference current variation value, and determine a state of the battery cell as a failure state in which an unknown discharge failure occurs if the current slope variation value exceeds a predetermined battery cell specific failure determination reference current slope variation value.
5. The apparatus of claim 4, further comprising at least one of a speaker (130), a display unit (140), and a lamp (150), wherein the control unit (160) further comprises a failure detection notification unit (163) configured to express the failure state of the battery cell through at least one of the speaker, the display unit, and the lamp.

Description

[Technical Field] The present invention relates to an apparatus and method for detecting failure of a battery cell due to an unknown discharge current, and more particularly to an apparatus and method for detecting failure of a battery cell due to an unknown discharge current, which can reduce the time required for failure detection compared to a conventional battery cell failure detection technique by using a real-time current monitoring method. [Background Art] Recently, research and development on secondary batteries have been actively conducted. Here, the secondary batteries, as batteries that can be charged and discharged, mean that they include conventional Ni/Cd batteries and Ni/MH batteries, and recent lithium ion batteries. Among the secondary batteries, the lithium ion battery has an advantage that the energy density is much higher than that of the conventional Ni/Cd battery and Ni / MH battery, and further, the lithium ion battery can be manufactured with a tendency of a small size so that it is used as a power source for a mobile apparatus. In addition, the usage range of the lithium ion battery extends as a power source for electric vehicles, so that the lithium ion battery attracts attention as a next generation energy storage medium. Meanwhile, in the battery cell production process, an unknown discharge current that may occur in a manufactured battery cell is a type of failure that abnormally drops the voltage of the battery cell. The conventional technology for detecting the failure of a battery cell based on the voltage characteristic of the battery cell takes a long period of time from the completion of the production of the battery cell to the time point when the failure is detected so that the production rate of the battery cell is lowered. Accordingly, the development of a new battery cell failure detection technique using an unknown discharge current, which can reduce the detection time compared to a conventional failure detection technique of a battery cell based on the voltage characteristic of a battery cell in order to increase the production speed of the battery cell, is required. Prior art battery cell failure detection is disclosed e.g. by JP 3 649903 B2 : CHARACTERISTIC EVALUATING METHOD AND CHARACTERISTIC EVALUATING DEVICE FOR ALKALINE ZINC STORAGE BATTERY; JP 2012 003863 A : METHOD AND DEVICE FOR DETECTING LITHIUM DENDRITE PRECIPITATION; US 2009/218990 A1 : Thermal Runaway Protection System for a Battery Charger; JP 3317184 B2 : POWER SUPPLY AND METHOD FOR DETECTING DETERIORATION OF POWER SUPPLY; US 2012/182021 A1 : DIFFERENTIAL CURRENT MONITORING FOR PARALLEL-CONNECTED BATTERIES; US 2014/266229 A1 : SYSTEM AND METHODS FOR DETECTION OF INTERNAL SHORTS IN BATTERIES; JP 3 596097 B2 : MINOR SHORT CIRCUIT DETECTING METHOD FOR CHARGEABLE LITHIUM BATTERY AND CHARGING APPARATUS. [Disclosure] [Technical Problem] The present invention provides a new apparatus and method for detecting failure of a battery cell due to an unknown discharge current, which can reduce the detection time compared to a conventional battery cell failure detection method using an unknown discharge current. [Technical Solution] A method for detecting failure of a battery cell due to an unknown discharge current which is not covered by the claimed invention includes: a detector connection operation of connecting a detector in series between the battery cell and a power supply for supplying a charging power; a test proper charging time determination operation of determining whether the charging of the battery cell progresses by the charging power in excess of a predetermined battery cell specific charging reference time; a current real-time measurement operation of measuring a current value of the battery cell in real time if the charging of the battery cell progresses in excess of the battery cell specific charging reference time; an unknown discharge current monitoring operation of determining whether the current value of the battery cell measured in real time exceeds a predetermined battery cell specific failure determination reference current range value; and a failure detection completion operation of determining a state of the battery cell as a failure state in which an unknown discharge occurs if the current value of the battery cell exceeds the predetermined battery cell specific failure determination reference current range value. The failure detection completion operation may further include a failure detection notification operation of expressing the failure state through at least one of a speaker, a display unit, and a lamp. In accordance with one exemplary embodiment, provided is a method for detecting failure of a battery cell due to an unknown discharge current as defined in the appended set of claims, and the method includes: a detector connection operation of connecting a detector in series between the battery cell and a power supply for supplying a charging power; a test proper charging time det