CN110873849B - Battery control apparatus and method for detecting internal short circuit of battery - Google Patents
Battery control apparatus and method for detecting internal short circuit of battery Download PDFInfo
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- CN110873849B CN110873849B CN201910742743.9A CN201910742743A CN110873849B CN 110873849 B CN110873849 B CN 110873849B CN 201910742743 A CN201910742743 A CN 201910742743A CN 110873849 B CN110873849 B CN 110873849B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/382—Arrangements for monitoring battery or accumulator variables, e.g. SoC
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
- G01R19/16566—Circuits and arrangements for comparing voltage or current with one or several thresholds and for indicating the result not covered by subgroups G01R19/16504, G01R19/16528, G01R19/16533
- G01R19/16576—Circuits and arrangements for comparing voltage or current with one or several thresholds and for indicating the result not covered by subgroups G01R19/16504, G01R19/16528, G01R19/16533 comparing DC or AC voltage with one threshold
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/389—Measuring internal impedance, internal conductance or related variables
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/425—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
- H01M10/4257—Smart batteries, e.g. electronic circuits inside the housing of the cells or batteries
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/44—Methods for charging or discharging
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/425—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
- H01M2010/4271—Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/425—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
- H01M2010/4278—Systems for data transfer from batteries, e.g. transfer of battery parameters to a controller, data transferred between battery controller and main controller
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Power Engineering (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Secondary Cells (AREA)
- Charge And Discharge Circuits For Batteries Or The Like (AREA)
- Tests Of Electric Status Of Batteries (AREA)
Abstract
Disclosed are a battery control apparatus and a method for detecting an internal short circuit of a battery, which may include: acquiring first charge state information related to a charge state of a battery; detecting a first reference time point when the first charge state information satisfies a reference condition; acquiring second charge state information related to a charge state of the battery; detecting a second reference time point when the second charge state information satisfies the reference condition; and detecting an internal short circuit of the battery based on a difference between a charged amount from the first reference time point to the second reference time point and a discharged amount from the first reference time point to the second reference time point.
Description
This application claims the priority and benefit of korean patent application No. 10-2018-0094543, filed on korean intellectual property office at 13.8.2018, and korean patent application No. 10-2019-0088298, filed on korean intellectual property office at 22.7.2019, the entire contents of which are incorporated herein by reference.
Technical Field
Exemplary embodiments of the present invention relate to a battery control apparatus and a method for detecting an internal short circuit of a battery.
Background
With the development of electrical and electronic technologies, the use of portable electronic products that are small and light and have various functions is sharply increasing. Batteries are generally used as power supply devices for the operation of portable electronic products, and rechargeable batteries, which are charged and reusable, are mainly used.
Unlike primary batteries, which cannot be charged, rechargeable batteries are rechargeable and dischargeable batteries. Rechargeable batteries are used for portable small electronic devices such as portable phones or notebook computers, or are widely used as power sources for driving motors of electric tools, vehicles, and the like. The interior of the rechargeable battery may be formed of a positive electrode, a negative electrode, a separator, an electrolyte, etc., and the case may be formed of a metal plate or a pouch.
A rechargeable battery having a high energy density may cause problems in safety, such as thermal runaway (thermal runaway), and particularly, a case where a positive electrode and a negative electrode within the rechargeable battery are short-circuited so that the rechargeable battery is overheated is a representative example. The internal short circuit is caused by the functional damage of the separator, and examples thereof include deformation caused by external impact, metallic foreign materials included in the manufacturing process, and formation of dendrite of lithium or copper caused by electrochemical reaction.
In the related art, a technology of detecting a state of an internal short circuit of a rechargeable battery in advance and preventing the internal short circuit is developed. In the related art scheme, an inspection time of several tens of minutes or more is required in a state where the voltage of the rechargeable battery is very stable (no load or very low load). Therefore, there are disadvantages in that: an internal short circuit generated in a state where the rechargeable battery is continuously charged or discharged cannot be detected.
The above information disclosed in this background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.
Disclosure of Invention
The present invention has been made in an effort to provide a battery control apparatus and a method for detecting an internal short circuit of a battery, which are capable of preventing thermal runaway of the battery due to the internal short circuit by effectively detecting the internal short circuit of the battery.
An exemplary embodiment of the present invention provides a method for detecting an internal short circuit of a battery, which may include: acquiring first charge state information related to a charge state of a battery; detecting a first reference time point when the first charge state information satisfies a reference condition; acquiring second charge state information related to a charge state of the battery; detecting a second reference time point when the second charge state information satisfies the reference condition; and detecting an internal short circuit of the battery based on a difference between a charged amount from the first reference time point to the second reference time point and a discharged amount from the first reference time point to the second reference time point.
The step of detecting the internal short circuit may include: determining that an internal short circuit has occurred in the battery when a difference between the charge amount and the discharge amount is equal to or greater than a threshold value.
Each of the first state of charge information and the second state of charge information may include a state of charge (SOC) of the battery, and the reference condition may include a reference SOC.
The reference condition may include a full charge condition. In an exemplary embodiment, each of the first and second charge state information may include a current value and a voltage value of the battery, respectively, and the full charge condition may include a reference current value and a reference voltage value. Further, the step of detecting the first reference time point may include detecting the first reference time point when a current value included in the first state of charge information of the battery is equal to or less than a reference current value and a voltage value included in the first state of charge information of the battery is equal to or greater than a reference voltage value, and the step of detecting the second reference time point may include detecting the second reference time point when the current value included in the second state of charge information of the battery is equal to or less than the reference current value and the voltage value included in the second state of charge information of the battery is equal to or greater than the reference voltage value.
The method may further comprise: determining whether the first charge state information and the second charge state information are approximate to each other within a predetermined range, wherein the step of detecting the internal short circuit may be performed when the first charge state information and the second charge state information are approximate to each other within the predetermined range.
The method may further comprise: determining whether the charged amount and the discharged amount are equal to or greater than a predetermined value, wherein the step of detecting an internal short circuit may be performed when at least one of the charged amount and the discharged amount is equal to or greater than a predetermined value.
The method may further comprise: determining whether a time interval between the first reference time point and the second reference time point is within a threshold range, wherein the step of detecting the internal short circuit may be performed when the time interval is within the threshold range.
The threshold range may be a maximum of 48 hours.
The method may further comprise: when the first reference time point is detected, accumulating an amount of charging current supplied from the charging device to the battery and an amount of discharging current supplied from the battery to the load; and calculating the charge amount and the discharge amount based on the accumulated charge current amount and discharge current amount when the second reference time point is detected.
The method may further comprise: after the step of calculating the charge amount and the discharge amount, the accumulated charge current amount and discharge current amount are reset.
Another exemplary embodiment of the present invention provides a battery control apparatus, which may include: a measurement unit configured to measure a voltage, a current, and a temperature of the battery; a detector that acquires charge state information regarding a charge state of the battery based on at least one of a voltage value, a current value, and a temperature value of the battery measured by the measurement unit, and detects a reference time point when the charge state information satisfies a reference condition; an accumulator that accumulates a charging current amount and a discharging current amount of the battery until a second reference time point is detected by the detector when the first reference time point is detected by the detector, and calculates a charging amount and a discharging amount of the battery based on the accumulated charging current amount and discharging current amount; and an internal short detector that detects an internal short of the battery based on a difference between a charged amount from the first reference time point to the second reference time point and a discharged amount from the first reference time point to the second reference time point.
The internal short detector may determine that an internal short occurs in the battery when a difference between the charged amount and the discharged amount is equal to or greater than a threshold value.
The state-of-charge information may include an SOC of the battery, and the reference condition may include a reference SOC.
The reference condition may include a full charge condition. In an exemplary embodiment, the state of charge information may include a current value and a voltage value of the battery, and the full charge condition may include a reference current value and a reference voltage value. Further, the detector may detect the reference time point when the current value of the battery is equal to or less than the reference current value and the voltage value of the battery is equal to or greater than the reference voltage value.
The internal short circuit detector may detect the internal short circuit based on a difference between the charged amount and the discharged amount when the state of charge information at the first reference time point and the state of charge information at the second reference time point of the battery are approximate to each other within a predetermined range.
The internal short circuit detector may detect an internal short circuit based on a difference between the charged amount and the discharged amount when the charged amount and the discharged amount are equal to or greater than a predetermined value.
The internal short circuit detector may detect an internal short circuit based on a difference between the charged amount and the discharged amount when a time interval between a first reference time point and a second reference time point is within a threshold range.
The threshold range may be a maximum of 48 hours.
According to the exemplary embodiments of the present invention, there are effects that an internal short circuit of a battery can be effectively detected and thermal runaway of the battery can be prevented.
Drawings
Fig. 1 is a block diagram showing the configuration of a battery control apparatus according to an exemplary embodiment of the present invention.
Fig. 2 is an equivalent circuit of a battery according to an exemplary embodiment of the present invention.
Fig. 3 is a graph illustrating changes in the amount of charge and the amount of discharge according to the occurrence of an internal short circuit of the battery.
Fig. 4 is a flowchart illustrating a method of the battery control apparatus for detecting an internal short circuit of the battery according to an exemplary embodiment of the present invention.
Detailed Description
Hereinafter, a battery control apparatus according to an exemplary embodiment of the present invention will be described in more detail with reference to fig. 1 to 3.
Fig. 1 is a block diagram showing the configuration of a battery control apparatus according to an exemplary embodiment of the present invention, and fig. 2 is an equivalent circuit of a battery according to an exemplary embodiment of the present invention.
Referring to fig. 1, a battery control apparatus 1 according to an exemplary embodiment of the present invention may include a battery 10, a measurement unit 20, a detection unit 30, and a control unit 40, and may prevent thermal runaway of the battery by sensing an internal short circuit of the battery 10.
The battery 10, which is a chargeable and dischargeable secondary battery, may be referred to as a battery cell.
Referring to fig. 2, the battery 10 may include two terminals B + and B-, and may be charged by an external charging device (not shown) or discharged by an external load (not shown) via the two terminals B + and B-. For convenience of description, it is described that the charging device is provided outside the battery control device 1, but the exemplary embodiment of the present invention is not limited thereto.
As shown in FIG. 2, battery 10 may include an internal resistance R B And an internal resistor R B It may have a resistance value of several m Ω to several hundred m Ω. When an internal short circuit occurs in the battery 10, the same effect as that of the electrical connection of the switch S inside the battery 10 is produced.
When the switch S is electrically connected, short-circuit current I short Into the short-circuit resistor R S Causing battery 10 to discharge. In this case, the short-circuit resistance R S It is possible to have a resistance value in a wide range of several m Ω to several k Ω.
The battery 10 is charged by one or more of a Constant Current (CC) charge in which the battery is charged with a constant current from an initial stage to a complete stage of charging, a Constant Voltage (CV) charge in which the battery is charged with a constant voltage from the initial stage to the complete state of charging, and a CC-CV charge in which the battery is charged with a constant current at the initial stage of charging and is charged with a constant voltage at the complete stage of charging. CC charging is a charging method for supplying a constant current to the battery 10 and charging the battery 10 until the battery 10 reaches a predetermined set voltage. When the CC charging is performed, the voltage of the battery 10 may increase together with the charge amount of the battery 10. In the present specification, the charge amount indicates an amount of charge or an amount of electric capacity (or capacity) that a charging device (not shown) supplies to the battery 10 to charge the battery 10, and is different from a state of charge (SOC) indicating a charge level. Further, the discharge amount indicates an amount of charge or an amount of capacitance supplied from the battery 10 to a load (not shown).
When the charge and discharge of the battery 10 are repeated under the same conditions, the charge amount between the full charge time points of the battery 10 (i.e., after the battery 10 is fully charged and then discharged until the battery 10 is fully charged again) is slightly larger than the discharge amount. Such differences are due to various energy losses of the battery 10 during the charging/discharging process (including heat generation and self-discharge, etc.).
As shown in fig. 2, when an internal short circuit occurs in the battery 10, a short-circuit current I is generated short And this results in a resistance R due to short-circuiting in the battery S Resulting in energy loss. Therefore, when an internal short circuit occurs in the battery 10, the amount of charge (discharged amount) that the battery 10 can supply to a load (not shown) is significantly smaller than the amount of charge (charged amount) that the charging device (not shown) can supply to the battery 10 before the internal short circuit occurs, compared to the amount of charge (charged amount) that the charging device (not shown) can supply to the battery 10. That is, in the battery 10 in which the internal short circuit occurs, some of the amount of charge (amount of charge) supplied by the charging device for charging the battery 10 during charging is included in the short-circuit resistance R S The amount of charge actually accumulated in the battery 10 is smaller than the amount of charge supplied from the charging device before the internal short circuit occurs, compared to the amount of charge supplied from the charging device. In addition, in the battery 10 in which the internal short circuit occurs, at the time of discharge, the short-circuit resistance R is included S The internal short circuit path of (b) consumes energy, and therefore, the amount of charge supplied from the battery 10 to the external load is smaller than the amount of charge actually discharged from the battery 10 before the internal short circuit occurs, as compared to the amount of charge actually discharged from the battery 10.
Referring to such characteristics, the battery control apparatus 1 according to the exemplary embodiment monitors the charge amount and the discharge amount of the battery 10 to detect an internal short circuit of the battery 10. A detailed configuration for detecting an internal short circuit of the battery 10 by monitoring the charge amount and the discharge amount of the battery 10 will be described below.
The measurement unit 20 continuously measures the voltage V, the current I, and the temperature T of the battery 10, and transmits the measured voltage value, current value, and temperature value to the detection unit 30. In this specification, the current I of the battery 10 represents a charging current supplied from a charging device (not shown) to the battery 10 or a discharging current supplied from the battery 10 to an external load (not shown).
The detection unit 30 includes a detector 31, an accumulator 32, and an internal short detector 33, monitors the charge amount and the discharge amount of the battery 10 and detects an internal short of the battery 10, and generates a short detection signal Ds.
The detector 31 acquires charge state information about the charge state of the battery 10 from the temperature value, the voltage value, and the current value of the battery 10 received from the measurement unit 20 at the time of charging the battery 10. Here, the state of charge information may include a temperature value, a voltage value, and a current value of the battery 10 measured by the measurement unit 20, or may include the SOC of the battery 10.
Further, the detector 31 detects a point of time (hereinafter, referred to as a "reference point of time") when the charge state information of the battery 10 satisfies a predetermined reference condition.
In the detector 31, the reference condition for detecting the reference time point may include a reference SOC. In this case, the detector 31 may detect a time point when the SOC of the battery 10 reaches a predetermined reference SOC as a reference time point. The reference SOC may be an SOC that becomes a reference for determining whether the battery 10 is in a fully charged state, but exemplary embodiments are not limited thereto, and thus, the reference SOC may be set to a lower or higher value than the SOC that becomes a reference for determining a fully charged state.
In the detector 31, the reference condition for detecting the reference time point as the full charge condition of the battery 10 may include at least one condition for determining the full charge state of the battery 10.
As one example, the reference condition may include a reference voltage value and a reference current value for determining a full charge state of the battery 10. In this case, the detector 31 may detect, as the reference time point, a time point at which the voltage value of the battery 10 is equal to or greater than the reference voltage value and the current value of the battery 10 is equal to or less than the reference current value. The full charge condition may include other conditions besides the reference voltage value and the reference current value, and this may vary according to a scheme in which the battery control apparatus 1 determines the full charge state of the battery 10.
In the detector 31, the reference condition for detecting the reference time point may include a reference voltage value and a reference current value for determining a predetermined state of the battery 10 other than the fully charged state. In this case, the reference voltage value and the reference current value may correspond to voltage values and current values that become references for determining whether the battery 10 reaches a predetermined state of charge before or after the battery 10 reaches a fully charged state. In this case, similar to the detection of the fully charged state, the detector 31 may detect, as the reference time point, a time point at which the voltage value of the battery 10 is equal to or greater than the reference voltage value and the current value of the battery 10 is equal to or less than the reference current value.
When the reference time point is detected by the detector 31, the accumulator 32 accumulates the charge and discharge amounts of the battery 10 until a subsequent reference time point is detected to calculate the charge and discharge amounts of the battery 10 during a time period between the two reference time points (hereinafter, referred to and used as a "comparison time period"). Here, the accumulator 32 may accumulate the charging current supplied from the charging device to the battery 10 during the comparison period and obtain the charged amount during the comparison period by the accumulated amount of the charging current, accumulate the discharging current supplied from the battery 10 to the external load during the comparison period and obtain the discharged amount during the comparison period by the accumulated amount of the discharging current.
In such a scheme, the accumulator 32 may calculate the charge amount and the discharge amount separately for each of a plurality of comparison time periods having two different reference time points (as the start reference time point and the end reference time point). For this, when the reference time point is detected, the accumulator 32 is reset to reset the amount of charging current and the amount of discharging current accumulated during the previous comparison period, and the accumulation of the charging current and the discharging current is restarted. The start reference time point of each comparison period may be the same as the end reference time point of the previous comparison period, and the end reference time point may be the same as the start reference time point of the subsequent comparison period.
The accumulator 32 may be a single accumulator having a sign, and may include two accumulators for accumulating the amount of charging current and the amount of discharging current, respectively, but the exemplary embodiment is not limited thereto.
When the charge amount and the discharge amount during each comparison period are calculated by the accumulator 32, the internal short detector 33 detects the internal short IS of the battery 10 based on the calculated charge amount and discharge amount, and transmits a detection signal Ds including information on whether the internal short IS occurs to the control unit 40.
The control unit 40 may control connection or disconnection of an external charging device (not shown) or a load (not shown) connected to the battery 10 based on the detection signal Ds received from the internal short detector 33. For example, when the detection signal Ds indicating the occurrence of the internal short of the battery 10 is generated by the internal short detector 33, the control unit 40 may interrupt the connection of an external charging device (not shown) or a load (not shown) connected to the battery 10.
Therefore, the battery control apparatus 1 may detect an internal short circuit of the battery 10 and control the connection between the battery 10 and the charging apparatus (or the load) according to the detection result of the internal short circuit, thereby preventing thermal runaway of the battery 10 due to the internal short circuit.
As described above, when the internal short circuit of the battery 10 is to be detected by comparing the charged amount and the discharged amount of the battery 10 during the comparison period having the start reference time point and the end reference time point, the amount of charge (or SOC) held by the battery 10 at the start reference time point of the comparison period and the amount of charge (or SOC) held by the battery 10 at the end reference time point need to be equal to or approximate to each other at a predetermined level or higher. This is because, in addition to the internal short circuit, a difference between the amount of charge held by the battery 10 at the start reference time point of the comparison period and the amount of charge held by the battery 10 at the end reference time point of the comparison period affects a difference between the amount of charge and the amount of discharge of the battery 10 during the comparison period, and thus, it is difficult to detect the internal short circuit by comparing the amount of charge and the amount of discharge.
Therefore, the battery control apparatus 1 sets the reference condition to detect the time when the state of charge of the battery 10 reaches a state (for example, a fully charged state) in which the amount of charge held by the battery 10 is determined to have a predetermined value that coincides with the start reference time point and the end reference time point of the comparison period.
In addition, when the internal short detector 33 determines that the state of charge of the battery 10 at the start reference time point and the state of charge of the battery 10 at the end reference time point are different from each other at a predetermined level or higher due to a change in the ambient environment of the battery 10 for one comparison period, the internal short detector 33 may omit the detection of the internal short. For example, when the full charge condition for determining the full charge state of the battery 10 is set to vary according to a change in the surrounding environment (such as temperature, etc.), the full charge conditions for the start reference time point and the end reference time point of one comparison period may be different from each other. Accordingly, the internal short circuit detector 33 compares the state of charge information (e.g., voltage value, current value, temperature value, etc.) of the battery 10 at the start reference time point of the comparison period and the state of charge information (e.g., voltage value, current value, temperature value, etc.) at the end reference time point with each other to determine whether an internal short circuit is detected.
Further, the internal short circuit detector 33 may detect the internal short circuit by comparing the charge amount and the discharge amount only when at least one of the charge amount and the discharge amount generated during the comparison period is equal to or greater than a predetermined value. This is because, if the charge amount and the discharge amount during the comparison period are too small, the difference between the charge amount and the discharge amount due to the internal short circuit is insignificant, and the reliability of the internal short circuit detection is reduced.
Further, the internal short detector 33 compares the charge amount and the discharge amount with each other to detect the internal short only when the length of the comparison period (i.e., the time interval between the start reference time point and the end reference time point of the comparison period) is within a predetermined threshold range. This is to prevent a decrease in detection reliability due to internal short detection in the following cases: the information of the accumulator 32 may be unreliable because the time interval between the start reference time point and the end reference time point is so short that the difference between the charged amount and the discharged amount due to the internal short is not significant, or the time interval between the start reference time point and the end reference time point is so long that the information of the accumulator 32 may be unreliable. Therefore, the internal short circuit detector 33 sets a threshold range so that a minimum time for generating a difference between the charged amount and the discharged amount due to the internal short circuit as a detectable level is set to a minimum value and a maximum time for ensuring the reliability of the accumulator 32 to a predetermined level or higher is set to a maximum value, and compares the charged amount and the discharged amount by comparing the charged amount and the discharged amount only when the length of the comparison period (time interval between the start reference time point and the end reference time point) is within the threshold range to detect the internal short circuit. The threshold range may be set to a minimum of 2 hours to a maximum of 48 hours, but the exemplary embodiments are not limited thereto.
Hereinafter, a method for detecting the internal short IS of the battery 10 by the battery control apparatus 1 will be described with reference to fig. 3.
Fig. 3 is a graph schematically showing changes in the amount of charge and the amount of discharge according to the occurrence of an internal short circuit of the battery 10, and shows a case where the battery 10 is repeatedly charged and discharged by a CC-CV charging method and a CC discharging method as an example.
In the graph of fig. 3, t represents time, I represents a charging current supplied from the charging device to the battery 10 or a discharging current supplied from the battery 10 to the load, and C represents a charge amount or a discharge amount. Referring to fig. 3, when a charging current is supplied to the battery 10, the charge amount of the battery 10 continuously increases, and when a discharging current is supplied from the battery 10, the discharge amount of the battery 10 continuously increases.
In fig. 3, as an example, the detector 31 acquires information on the state of charge of the battery 10 using the information obtained by the measurement unit 20, and detects a plurality of time points at which the state of charge information of the battery 10 satisfies the full charge condition as reference time points t1, t2, t3, and t4. Further, each time the reference time points t1, t2, t3, and t4 are detected, the detector 31 stores information on the state of charge of the battery 10 at the corresponding time points in a memory (not shown).
When the reference time points t1, t2, t3, and t4 are detected, the accumulator 32 calculates the charge amounts cc1, cc2, and cc3 and the discharge amounts dc1, dc2, and dc3 for a plurality of comparison time periods p1, p2, and p3 in which each of the reference time points t1, t2, t3, and t4 is set as a start reference time point or an end reference time point. The accumulator 32 may calculate the charge amount and the discharge amount during each of the comparison time periods p1, p2, and p3 by accumulating the charge current and the discharge current for each of the plurality of comparison time periods p1, p2, and p 3.
Specifically, when the reference time point t1 is detected, the accumulator 32 accumulates each of the amount of charging current and the amount of discharging current until the reference time point t2 is detected. In addition, when the reference time point t2 is detected, the charge amount cc1 and the discharge amount dc1 of the comparison period p1 are calculated by the charge current amount and the discharge current amount accumulated from the reference time point t1 to the reference time point t2. Further, the amount of charging current and the amount of discharging current accumulated so far are reset, and then the amount of charging current and the amount of discharging current are accumulated respectively until the reference time point t3 is detected after the start of new accumulation.
In addition, when the reference time point t3 is detected, the charge amount cc2 and the discharge amount dc2 of the comparison period p2 are calculated by the amount of charge current and the amount of discharge current accumulated from the reference time point t2 to the reference time point t3. Further, the amount of charging current and the amount of discharging current accumulated so far are reset, and then the amount of charging current and the amount of discharging current are accumulated respectively until the reference time point t4 is detected after the start of new accumulation.
In addition, when the reference time point t4 is detected, the charge amount cc3 and the discharge amount dc3 of the comparison period p3 are calculated by the amount of charge current and the amount of discharge current accumulated from the reference time point t3 to the reference time point t4.
In this scheme, the internal short circuit detector 33 compares the calculated charge amount with the discharge amount each time, calculates the charge amount and the discharge amount in each of the comparison time periods p1, p2, and p3, and determines that an internal short circuit has occurred when the difference between the charge amount and the discharge amount is equal to or greater than a threshold value. In addition to the internal short circuit, when the charge/discharge of the battery 10 is in progress, the energy of the battery 10 is lost due to heat generation or the like. However, the amount of energy lost in this case is insignificant and can be ignored by appropriately setting the threshold value at which the internal short circuit is detected. That is, the battery control apparatus 1 sets the threshold value for internal short detection to a predetermined value or more, so that it is possible to avoid a situation in which energy loss due to factors other than an internal short is erroneously determined to occur due to the internal short.
Taking fig. 3 as an example, the comparison period p1 is a period before the occurrence of the internal short circuit, and the charge amount and the discharge amount during the comparison period p1 are very similar to each other.
Then, in the comparison period p2, an internal short circuit occurs during the charging of the battery 10, so that the amount of charge cc2 in the comparison period p2 is larger than the amount of charge cc1 in the comparison period p1 in which the battery 10 is in a normal state. Therefore, the difference d1 between the discharged amount dc2 and the charged amount cc2 during the comparison period p2 becomes equal to or greater than the threshold value, and the internal short of the battery 10 can be detected by the internal short detector 33.
Then, in the comparison period p3, charging and discharging are performed in a state where the internal short circuit occurs, so that the energy loss due to the internal short circuit further increases. Therefore, the difference d2 between the discharge amount dc3 and the charge amount cc3 during the comparison period p3 increases compared to the difference during the previous comparison period p 2. Therefore, the internal short of the battery 10 is detected again by the internal short detector 33.
In the above-described battery control apparatus 1, the measurement unit 20, the detection unit 30, or the control unit 40 may be executed by one or more Central Processing Units (CPUs) or processors implemented by other chipsets, microprocessors, or the like.
Hereinafter, a battery control method according to an exemplary embodiment of the present invention will be described with reference to fig. 4.
Fig. 4 is a flowchart illustrating a method for detecting an internal short circuit according to an exemplary embodiment of the present invention.
The method for detecting an internal short circuit in fig. 4 may be performed by the battery control apparatus 1 described with reference to fig. 1 and 2.
Referring to fig. 4, the detection unit 30 acquires the charge state information of the battery 10 (S10) and compares the charge state information with the reference condition to determine whether a reference time point at which the charge state information of the battery 10 satisfies the reference condition is detected (S11).
In step S10, the detection unit 30 receives the results of measuring the voltage, current, and temperature of the battery 10 from the measurement unit 20, and acquires the charge state information about the charge state of the battery 10 from the measurement results. Here, the state of charge information may include a temperature value, a voltage value, and a current value of the battery 10 measured by the measurement unit 20, or may include an SOC of the battery 10.
In step S11, the reference time point serves as a start time point or an end time point of the comparison period, and the reference conditions for detecting the reference time point may include the reference SOC, the full charge condition, or the reference voltage value and the reference current value.
The detection unit 30 repeatedly performs the step S10 of acquiring the charge state information of the battery 10 and the step S11 of determining whether the reference time point is detected by comparing the charge state information with the reference condition until the reference time point is detected. In addition, when the reference time point is detected through step S11, the detection unit 30 accumulates the amount of charging current supplied from the charging device to the battery 10 and the amount of discharging current supplied from the battery 10 to the load (S12). Further, the detection unit 30 acquires the charge state information of the battery 10 (S13) and determines whether a reference time point at which the charge state information of the battery 10 satisfies the reference condition is detected by comparing the acquired charge state information with the reference condition (S14).
The detection unit 30 repeatedly performs the step S12 of accumulating the amount of charging current and the amount of discharging current, the step S13 of acquiring the charge state information of the battery 10, and the step S14 of determining whether the reference time point is detected by comparing the charge state information with the reference condition until the reference time point is detected. In addition, when the reference time point is detected through step S14, the charge and discharge amounts of the battery 10 are calculated by using the charge and discharge current amounts accumulated so far (S15). In addition, the amount of charging current and the amount of discharging current accumulated so far are reset by resetting the accumulator 32 (S16).
In step S15, the amount of charging current and the amount of discharging current accumulated from the reference time point detected through step S11 to the reference time point detected through step S14 are used in order to calculate the amount of charge and the amount of discharge. That is, in this case, in the comparison period for calculating the charge amount and the discharge amount, the start time point may become the reference time point detected by step S11, and the end time point may become the reference time point detected by step S14.
On the other hand, before detecting the internal short circuit of the battery 10 by comparing the charged amount and the discharged amount in the comparison period, the detection unit 30 first checks whether the present situation is a state in which the internal short circuit detection is possible in order to ensure the detection reliability (S17). In addition, if it is determined that the current state is a state in which internal short detection is possible, the amount of charge and the amount of discharge in the comparison period are compared, and the process proceeds to step S18 to perform internal short detection.
For example, in step S17, the detection unit 30 checks whether the state of charge information (e.g., voltage value, current value, temperature value, etc.) of the battery 10 at the time of detecting the reference time point through step S11 and the state of charge information (e.g., voltage value, current value, temperature value, etc.) of the battery 10 at the time of detecting the reference time point through step S14 are approximate to each other at a predetermined level or higher, and if both the state of charge information are approximate at the predetermined level or higher, the process may proceed to step S18. Specifically, when the difference between the temperature value of the battery 10 at the reference time point detected through step S11 and the temperature value of the battery 10 at the reference time point detected through step S14 is equal to or less than a predetermined value, the difference between the current value of the battery 10 at the reference time point detected through step S11 and the current value of the battery 10 at the reference time point detected through step S14 is equal to or less than a predetermined value, and the difference between the voltage value of the battery 10 at the reference time point detected through step S11 and the voltage value of the battery 10 at the reference time point detected through step S14 is equal to or less than a predetermined value, the detection unit 30 may determine that the charge state information of the battery 10 at the two reference time points is approximate.
Further, for example, in step S17, the detection unit 30 may check whether or not at least one of the charge amount and the discharge amount from the reference time point detected by step S11 to the reference time point detected by step S14 is equal to or greater than a predetermined value, and when the at least one of the charge amount and the discharge amount is equal to or greater than the predetermined value, the process may proceed to step S18.
Further, for example, in step S17, the detection unit 30 may compare the length of the comparison period in which the reference time point detected by step S11 is set as the start time point and the reference time point detected by step S14 is set as the end time point with a threshold range (for example, from minimum 2 hours to maximum 48 hours), and if the length of the comparison period is within the threshold range, the processing may proceed to step S18.
In step S17, if all the conditions listed above as an example are satisfied, the detection unit 30 may proceed to step S18 where the internal short detection is performed by comparing the charge amount and the discharge amount in the comparison period. However, since the exemplary embodiment is not limited thereto, even if only some of the conditions listed above as an example are satisfied, the detection unit 30 may proceed to step S18 in which the internal short detection is performed by comparing the charge amount and the discharge amount in the comparison period.
The above-described step S17 is to prevent the internal short detection from being performed in a case where the difference between the charge amount and the discharge amount calculated during the comparison period is increased to a value of the threshold value or more due to a factor other than the internal short, to prevent the internal short detection from being performed in a case where the difference between the charge amount and the discharge amount due to the internal short is not generated to a detectable level, or to prevent the internal short detection from being performed in a case where the reliability of the calculated charge amount and discharge amount is low.
When it is determined through step S17 that the present situation is not a situation in which the internal short detection is possible, the detection unit 30 proceeds to step S12 to start the accumulation of the amount of charging current and the amount of discharging current in a new comparison period. In this case, the reference time point previously detected through step S14 becomes a start time point of a new comparison period, and the reference time point detected later becomes an end time point of the new comparison period.
If it is determined at step S17 that the present situation is a situation in which the internal short detection is possible, the detection unit 30 determines whether the difference between the charged amount and the discharged amount from the reference time point detected through step S11 to the reference time point detected through step S14 is equal to or greater than the threshold value (S18). In addition, when the difference between the charged amount and the discharged amount is equal to or greater than the threshold value, it is determined that an internal short circuit has occurred in the battery 10 (S19), and the connection between the battery 10 and a charging device (not shown) or the connection between the battery 10 and a load is blocked (S20) to prevent thermal runaway of the battery 10.
In addition, in the present specification, it is described that the battery control apparatus 1 detects an internal short circuit of one battery 10 as an example, but the exemplary embodiment is not limited thereto. For example, the battery control apparatus 1 can detect the internal short of each battery by applying the internal short detection method even to a battery module in which a plurality of batteries are configured to be connected in series and/or in parallel. In this case, the voltage value of the battery 10 may correspond to the voltages of both terminals B + and B-of the battery 10, and the current of the battery 10 may correspond to a charging current supplied from a charging device to a battery module or a discharging current supplied from the battery module to a load.
While the invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. On the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
Claims (14)
1. A method for detecting an internal short circuit of a battery, the method comprising:
acquiring first charge state information related to a charge state of a battery;
detecting a first reference time point when the first charge state information satisfies a reference condition;
acquiring second charge state information related to a charge state of the battery;
detecting a second reference time point when the second charge state information satisfies the reference condition;
determining whether at least one of a charged amount from the first reference time point to the second reference time point and a discharged amount from the first reference time point to the second reference time point is equal to or greater than a predetermined value; and
detecting an internal short circuit of a battery based on a difference between the charged amount and the discharged amount when at least one of the charged amount and the discharged amount is equal to or greater than a predetermined value,
wherein each of the first state of charge information and the second state of charge information comprises a state of charge of the battery, and
the reference condition includes a reference state of charge.
2. The method of claim 1, wherein:
the step of detecting an internal short circuit includes: when the difference between the charge amount and the discharge amount is equal to or greater than a threshold value, it is determined that an internal short circuit has occurred in the battery.
3. The method of claim 1, wherein:
the reference condition also includes a full charge condition.
4. The method of claim 1, wherein:
each of the first charge state information and the second charge state information further includes a current value and a voltage value of the battery,
the reference condition further includes a reference current value and a reference voltage value,
the step of detecting the first reference time point includes detecting the first reference time point when a current value included in the first charge state information of the battery is equal to or less than a reference current value and a voltage value included in the first charge state information of the battery is equal to or greater than a reference voltage value, and
the step of detecting the second reference time point includes detecting the second reference time point when a current value of the battery included in the second state of charge information is equal to or less than a reference current value and a voltage value of the battery included in the second state of charge information is equal to or greater than a reference voltage value.
5. The method of claim 1, further comprising:
determining whether the first charge state information and the second charge state information are approximate to each other within a predetermined range,
wherein the step of detecting the internal short circuit is performed when the first charge state information and the second charge state information are approximate to each other within a predetermined range.
6. The method of claim 1, further comprising:
determining whether a time interval between the first reference point in time and the second reference point in time is within a threshold range,
wherein the step of detecting an internal short circuit is performed when the time interval is within a threshold range.
7. The method of claim 1, further comprising:
when the first reference time point is detected, accumulating an amount of charging current supplied from the charging device to the battery and an amount of discharging current supplied from the battery to the load; and
when a second reference time point is detected, the charge amount and the discharge amount are calculated based on the accumulated charge current amount and discharge current amount.
8. The method of claim 7, further comprising:
after the step of calculating the charge amount and the discharge amount, the accumulated charge current amount and discharge current amount are reset.
9. A battery control apparatus, comprising:
a measurement unit configured to measure a voltage, a current, and a temperature of the battery;
a detector that acquires charge state information related to a charge state of the battery based on at least one of a voltage value, a current value, and a temperature value of the battery measured by the measurement unit, and detects a reference time point when the charge state information satisfies a reference condition;
an accumulator that accumulates a charging current amount and a discharging current amount of the battery until a second reference time point is detected by the detector when the first reference time point is detected by the detector, and calculates a charging amount and a discharging amount of the battery based on the accumulated charging current amount and discharging current amount; and
an internal short detector detecting an internal short of the battery based on a difference between a charged amount from a first reference time point to a second reference time point and a discharged amount from the first reference time point to the second reference time point,
wherein the internal short circuit detector detects an internal short circuit based on a difference between the charged amount and the discharged amount when at least one of the charged amount and the discharged amount is equal to or greater than a predetermined value,
wherein the state of charge information includes a state of charge of the battery, and
the reference condition includes a reference state of charge.
10. The battery control apparatus according to claim 9, wherein:
the internal short detector determines that an internal short has occurred in the battery when a difference between the charged amount and the discharged amount is equal to or greater than a threshold value.
11. The battery control apparatus according to claim 9, wherein:
the reference condition also includes a full charge condition.
12. The battery control apparatus according to claim 9, wherein:
the charge state information further includes a current value and a voltage value of the battery,
the reference condition further includes a reference current value and a reference voltage value, and
the detector detects a reference time point when a current value of the battery is equal to or less than a reference current value and a voltage value of the battery is equal to or greater than a reference voltage value.
13. The battery control apparatus according to claim 9, wherein:
the internal short circuit detector detects an internal short circuit based on a difference between the charged amount and the discharged amount when state of charge information of the battery at a first reference time point and state of charge information of the battery at a second reference time point are approximate to each other within a predetermined range.
14. The battery control apparatus according to claim 9, wherein:
the internal short circuit detector detects an internal short circuit based on a difference between the charged amount and the discharged amount when a time interval between a first reference time point and a second reference time point is within a threshold range.
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KR20230093913A (en) | 2021-12-20 | 2023-06-27 | 삼성전자주식회사 | Method and apparatus for detecting short circuit of battery |
CN114252772B (en) * | 2021-12-22 | 2023-09-05 | 中国科学院电工研究所 | Internal short circuit diagnosis method and system for lithium ion battery |
CN114252792A (en) * | 2021-12-23 | 2022-03-29 | 蜂巢能源科技(无锡)有限公司 | Method and device for detecting internal short circuit of battery pack, electronic equipment and storage medium |
CN114264961B (en) * | 2021-12-23 | 2023-09-15 | 蜂巢能源科技(无锡)有限公司 | Method and device for detecting short circuit in battery cell and electronic equipment |
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US20090155674A1 (en) | 2007-12-18 | 2009-06-18 | Mitsumi Electronic Co., Ltd. | Battery Pack, Portable Device, Internal Short Detecting Method, and Internal Short Detecting Program |
JP2009170397A (en) * | 2007-12-18 | 2009-07-30 | Mitsumi Electric Co Ltd | Battery pack and portable device using the same, internal short-circuit detection method for the same, and internal short-circuit detection program |
JP5652802B2 (en) * | 2008-02-27 | 2015-01-14 | レノボ・イノベーションズ・リミテッド(香港) | Internal short circuit detection device and internal short circuit detection method for secondary battery |
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US8219333B2 (en) * | 2010-06-29 | 2012-07-10 | O2Micro, Inc | Battery management systems for protecting batteries from fault conditions |
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