Device and method for determining abnormality in battery cells

Abstract

The present invention includes a battery cell abnormality determination device that includes a magnetic field measurement unit that measures a magnetic field generated by a current flowing through a battery cell; and a control unit that calculates the capacity of the battery cell using the current calculated from the magnetic field measured by the magnetic field measurement unit, and the control unit determines an abnormality in the battery cell using the capacity of the battery cell.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] The present invention claims the benefit of priority based on Korean Patent Application No. 10-2019-0017277, filed on February 14, 2019, and all contents disclosed in the documents of the above Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a device and method for determining an abnormality in a battery cell. [Background technology]

[0003] Recently, research and development into secondary batteries has been actively conducted. Here, secondary batteries are batteries that can be charged and discharged, and include conventional Ni / Cd batteries, Ni / MH batteries, and the latest lithium-ion batteries. Among secondary batteries, lithium-ion batteries have the advantage of having a much higher energy density than conventional Ni / Cd batteries, Ni / MH batteries, etc. Furthermore, lithium-ion batteries can be manufactured in a compact and lightweight form, making them widely used as power sources for mobile devices. Furthermore, lithium-ion batteries are gaining attention as a next-generation energy storage medium, with their range of use expanding to include power sources for electric vehicles.

[0004] In addition, secondary batteries are generally used as battery packs including battery modules in which a plurality of battery cells are connected in series and / or parallel, and the state and operation of the battery packs are managed and controlled by a battery management system.

[0005] In applications such as electric vehicles and energy storage systems (ESS), a large number of battery cells are connected in series to ensure a high voltage, and in a battery pack including a large number of battery cells, a single current sensor is used to measure the charge and discharge current.

[0006] In such cases, the degree of battery deterioration is calculated based on the capacity or internal resistance of the entire battery pack, so it is not possible to determine whether a specific battery cell has an abnormal capacity or other internal abnormality.

[0007] Furthermore, when determining the capacity and deterioration of a battery pack, the measurement is not performed on a battery cell basis, which inevitably leads to large errors. Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention aims to measure the capacity and voltage of each battery cell and accurately measure the presence or absence of deterioration in battery capacity without error. [Means for solving the problem]

[0009] A battery cell abnormality determination device according to one embodiment of the present invention includes a magnetic field measurement unit that measures a magnetic field generated by a current flowing through a battery cell; and a control unit that calculates a capacity of the battery cell using a current calculated from the magnetic field measured by the magnetic field measurement unit, and the control unit determines an abnormality in the battery cell using the capacity of the battery cell.

[0010] The device for determining an abnormality in a battery cell according to an embodiment of the present invention further includes a magnetic field shield unit that collects a magnetic field generated by a current flowing through the battery cell.

[0011] The device for determining an abnormality in a battery cell according to an embodiment of the present invention further includes a storage unit that stores the capacity of the battery cell at the time of manufacture.

[0012] In the device for determining an abnormality in a battery cell according to an embodiment of the present invention, the control unit accumulates and integrates current for a first time period to calculate the capacity of the battery cell.

[0013] In the device for determining an abnormality in a battery cell according to an embodiment of the present invention, the control unit determines that the capacity of the battery cell has deteriorated when a difference between the capacity of the battery cell and the capacity of the battery cell at the time of manufacture exceeds a preset critical value.

[0014] The device for determining an abnormality in a battery cell according to an embodiment of the present invention further includes a voltage measurement unit that measures a voltage of the battery cell; the memory unit further stores a full charge / discharge time at the time of production of the battery cell; and the control unit calculates a full charge / discharge arrival time of the battery cell using the voltage of the battery cell, and determines that the internal resistance of the battery cell has increased if a difference between the measured full charge / discharge arrival time of the battery cell and the full charge / discharge arrival time of the battery cell at the time of production exceeds a preset critical value.

[0015] In the device for determining an abnormality in a battery cell according to an embodiment of the present invention, the magnetic field measuring unit and the magnetic field shielding unit are provided on either the negative electrode or the positive electrode of the battery cell.

[0016] The battery cell abnormality determination device according to an embodiment of the present invention is used for an energy storage system (ESS) or a battery cell for a vehicle.

[0017] A battery pack according to another embodiment of the present invention includes a plurality of battery cells connected in series; and a battery cell abnormality determination device provided in each battery cell, the battery cell abnormality determination device including a current measurement unit that measures a current flowing through each connected battery cell; and a control unit that calculates a capacity of the battery cell using the current, and the control unit determines an abnormality in the battery cell using the capacity of the battery cell.

[0018] In a battery pack according to another embodiment of the present invention, the current measuring unit measures the current using a magnetic field generated by the current flowing through the battery cell.

[0019] In a battery pack according to another embodiment of the present invention, the device for determining an abnormality in a battery cell further includes a storage unit that stores the capacity of the battery cell at the time of manufacture.

[0020] In a battery pack according to another embodiment of the present invention, the control unit calculates the capacity of the battery cell by accumulating the current for a first time period.

[0021] In a battery pack according to another embodiment of the present invention, the control unit determines that the capacity of the battery cell has deteriorated when a difference between the capacity of the battery cell and the capacity of the battery cell at the time of manufacture exceeds a preset critical value.

[0022] In a battery pack according to another embodiment of the present invention, the battery pack may further include a voltage measuring unit that measures a voltage of the battery cell, the memory unit may further store a full charge / discharge time at the time of manufacture of the battery cell, and the control unit may calculate a full charge / discharge time to be reached of the battery cell using the voltage of the battery cell, and may determine that an internal resistance of the battery cell has increased if a difference between the measured full charge / discharge time to be reached of the battery cell and the full charge / discharge time to be reached of the battery cell at the time of manufacture exceeds a predetermined critical value.

[0023] In a battery pack according to another embodiment of the present invention, the current measuring unit is provided at either the negative electrode or the positive electrode of the battery cell.

[0024] In a battery pack according to another embodiment of the present invention, the battery pack is a battery pack for an ESS or a vehicle.

[0025] A method for determining an abnormality in a battery cell according to another embodiment of the present invention includes the steps of measuring a magnetic field generated by a current flowing through the battery cell; measuring a capacity of the battery cell by accumulating a current derived from the measured magnetic field; and determining an abnormality in the battery cell using the measured capacity of the battery cell.

[0026] In another embodiment of the present invention, the method for determining an abnormality in a battery cell further includes measuring a voltage of the battery cell, and calculating a full charge / discharge time to reach the battery cell using the measured voltage of the battery cell; determining whether a difference between the full charge / discharge time to reach the battery cell and the full charge / discharge time to reach the battery cell at the time of manufacture exceeds a predetermined critical value; and determining that the internal resistance of the battery cell has increased when the difference between the full charge / discharge time to reach the battery cell and the full charge / discharge time to reach the battery cell at the time of manufacture exceeds the predetermined critical value.

[0027] In another embodiment of the present invention, the method for determining an abnormality in a battery cell may further include determining that the capacity of the battery cell has deteriorated if a difference between the capacity of the battery cell and the capacity of the battery cell at the time of manufacture exceeds a predetermined critical value.

[0028] In another embodiment of the method for determining an abnormality in a battery cell according to the present invention, if it is determined that the internal resistance of the battery cell has increased or the capacity of the battery cell has deteriorated, the method may further include transmitting a signal indicating an increase in the internal resistance of the battery cell or a signal indicating a deterioration in the capacity of the battery cell to the outside. [Effects of the Invention]

[0029] According to an embodiment of the present invention, it is possible to more accurately determine whether or not the capacity of a battery cell has deteriorated and whether or not the internal resistance of the battery cell has increased by measuring the capacity and voltage of the battery cell. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 2 is a block diagram showing the configuration of a battery control system. [Figure 2] FIG. 2 is a diagram showing a simplified configuration of a battery cell in a battery module. [Figure 3] 1 is a diagram illustrating a configuration of a battery cell abnormality determination device according to an embodiment of the present invention; [Figure 4a]1 is a diagram illustrating an example of an apparatus for determining an abnormality in a battery cell according to an embodiment of the present invention; [Figure 4b] 1 is a diagram illustrating an example of an apparatus for determining an abnormality in a battery cell according to an embodiment of the present invention; [Figure 4c] 1 is a diagram illustrating an example of an apparatus for determining an abnormality in a battery cell according to an embodiment of the present invention; [Figure 5] 4 is a flowchart of a method for determining an abnormality in a battery cell according to an embodiment of the present invention. [Figure 6] 10 is a flowchart of a method for determining an abnormality in a battery cell according to another embodiment of the present invention. [Figure 7] FIG. 10 is a diagram illustrating the configuration of a battery cell abnormality determination device according to another embodiment of the present invention. [Figure 8] 10 is a flowchart of a method for determining an abnormality in a battery cell according to another embodiment of the present invention. [Figure 9] 10 is a flowchart of a method for determining an abnormality in a battery cell according to another embodiment of the present invention. [Figure 10] 1 is a block diagram showing a hardware configuration of a battery management system according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, various embodiments of the present invention will be described with reference to the drawings. However, this is not intended to limit the present invention to the specific embodiments, and it should be understood that it includes various modifications, equivalents, and / or alternatives of the embodiments of the present invention. In connection with the description of the drawings, similar reference numerals may be used for similar components.

[0032] The terms used in this document are merely used to describe particular embodiments and are not intended to limit the scope of other embodiments. The singular term includes the plural term unless the context clearly indicates a different meaning. All terms used herein, including technical and scientific terms, may have the same meaning as commonly understood by a person of ordinary skill in the art of the present invention. Terms defined in commonly used dictionaries may be interpreted as having the same or similar meaning as the meaning they have in the context of the relevant art, and unless explicitly defined in this document, they should not be interpreted in an idealized or overly formal sense. In some cases, even terms defined in this document may not be interpreted to exclude embodiments of the present invention.

[0033] Furthermore, in describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are merely used to distinguish the component from other components, and do not limit the nature, order, or sequence of the components. When a component is described as being "coupled," "coupled," or "connected" to another component, it should be understood that the component may be directly coupled or connected to the other component, but that other components may also be "coupled," "coupled," or "connected" between each component.

[0034] FIG. 1 is a diagram illustrating a schematic configuration of a battery control system including a battery pack 1 according to an embodiment of the present invention and a host controller 2 included in the host system.

[0035] As shown in FIG. 1, the battery pack 1 includes a rechargeable battery module 10 made up of one or more battery cells, a switching unit 14 connected in series to the positive terminal side or the negative terminal side of the battery module 10 to control the flow of charge / discharge current of the battery module 10, and a battery management system 20 that monitors the voltage, current, temperature, etc. of the battery pack 1 and controls and manages it to prevent overcharging and over-discharging.

[0036] Here, the switching unit 14 is a semiconductor switching element for controlling the flow of current for charging or discharging the battery module 10, and may include, for example, at least one MOSFET.

[0037] In addition, the BMS 20 can measure or calculate the voltage and current of the gate, source, drain, etc. of the semiconductor switching element 14 to monitor the voltage, current, temperature, etc. of the battery pack 1, and can also measure the current, voltage, temperature, etc. of the battery pack using a sensor 12 provided adjacent to the semiconductor switching element 14. The BMS 20 is an interface that receives input of measured values ​​of the various parameters described above, and can include a plurality of terminals and circuits connected to these terminals for processing the input values.

[0038] In addition, the BMS 20 can also control the ON / OFF of the switching elements 14, for example, MOSFETs, and can monitor the status of the battery modules 10 by being connected to the battery modules 10.

[0039] The upper controller 2 can transmit a control signal for the battery module to the BMS 20. As a result, the operation of the BMS 20 can be controlled based on the signal applied from the upper controller. The battery cell of the present invention may be configured to be included in a battery pack used in an ESS (Energy Storage System) or a vehicle, etc. However, the present invention is not limited to such applications.

[0040] The configuration of the battery pack 1 and the configuration of the BMS 20 are well known, so a more detailed description will be omitted.

[0041] Meanwhile, a battery cell abnormality determination device according to an embodiment of the present invention is connected to each of a plurality of battery cells connected in series within a battery module 10 to determine whether or not there is an abnormality in the battery cell. While the current, voltage, and temperature of the battery module 10 itself can be measured using a sensor 12 to determine whether or not there is capacity degradation in the entire battery module 10, this method is difficult to measure accurately because it is not possible to measure whether or not there is capacity degradation on a battery cell-by-cell basis. Therefore, hereinafter, a battery cell abnormality determination device that can measure whether or not there is capacity degradation on a battery cell-by-cell basis will be considered.

[0042] FIG. 2 is a diagram showing a simplified configuration of a battery cell in a battery module.

[0043] In the battery module 10, a plurality of battery cells are connected in series / parallel.

[0044] Generally, a pack tray made of a highly thermally conductive material is provided on the lower surface of the module housing of the battery module 10. The pack tray can absorb heat generated in each cell of the battery cell assembly.

[0045] A battery cell abnormality determination device is disposed on the negative electrode terminal and positive electrode terminal side of the battery cell, which will be described in more detail with reference to FIGS. 3 to 4c below.

[0046] FIG. 3 is a diagram showing the configuration of a battery cell abnormality determination device 300 according to an embodiment of the present invention.

[0047] The battery cell abnormality determination device 300 may be disposed across the negative and positive terminals of the battery cell. In particular, the battery cell abnormality determination device 300 may be disposed on either the negative or positive tab extending from the battery cell to the outside. The battery cell abnormality determination device 300 includes a magnetic field shield unit 301, a magnetic field measurement unit 302, a voltage measurement unit 304, a temperature measurement unit 306, a control unit 308, a memory unit 310, and a communication unit 312.

[0048] The magnetic field shield unit 301 collects the magnetic field flowing through the battery cell in order to measure the current of the battery cell on a per-cell basis. The magnetic field shield unit 301 may be formed to surround at least a portion of the battery cell in order to accurately measure the magnetic field generated when current flows through the battery cell. Specifically, the magnetic field shield unit 301 may be formed to surround, for example, the lower side of the tab (positive or negative electrode) of the battery cell and the side portion of the battery cell. In this case, the magnetic field shield unit 301 is formed at a certain distance from the tab of the battery cell.

[0049] The magnetic field measurement unit 302 measures a magnetic field generated around the battery cell when a current flows through the battery cell. The magnetic field generated around the battery cell may be shielded by the magnetic field shield unit 301. The measured magnetic field may be used to indirectly calculate the current of the battery cell, for example, by the Biot-Savart law. For example, the control unit 308 may receive the strength of the magnetic field measured by the magnetic field measurement unit 302 and calculate the current flowing through the battery cell in real time. The current flowing through the battery cell calculated in real time may then be accumulated over a certain period of time to derive the capacity of the battery cell. Here, the certain period of time may be, for example, about one hour as a reference time for 1 C-rate discharge.

[0050] The voltage measurement unit 304 measures the voltage of the battery cell. The voltage measurement unit 304 is disposed across the negative terminal and positive terminal (between tabs) of the battery cell to measure the voltage of the battery cell. The voltage of the battery cell measured by the voltage measurement unit 304 is transmitted to the control unit 308. The control unit 308, which receives the voltage of the battery cell from the voltage measurement unit 304, calculates a full charge / discharge arrival time of the battery cell using the voltage of the battery cell. Here, the full charge / discharge arrival time is the time required for the battery cell to go from a fully discharged state to a fully charged state.

[0051] The temperature measuring unit 306 may measure the temperature of the battery cell. The temperature measuring unit 306 may be, for example, but is not limited to, a thermistor. The battery state of charge (SOC) of the battery cell may change depending on the temperature. Therefore, when calculating the capacity of the battery cell according to the current, the capacity of the battery cell may be calculated by also referring to the temperature of the battery cell. The change in the capacity of the battery cell according to the temperature of the battery cell may be calculated using a look-up table of the capacity of the battery cell according to the temperature of the battery cell, which is determined in advance through an experiment.

[0052] The control unit 308 calculates a real-time current of the battery cell using the magnetic field value of the battery cell received from the magnetic field measurement unit 302. The control unit 308 also calculates the capacity of the battery cell by accumulating the calculated current of the battery cell for a certain period of time. At this time, the control unit 308 may reflect the temperature measured by the temperature measurement unit 306 in the calculation of the capacity of the battery cell. A look-up table of the capacity change of the battery cell according to the temperature of the battery cell, which is determined in advance through an experiment, may be used when calculating the capacity of the battery cell.

[0053] The control unit 308 also compares the derived battery cell capacity with a pre-stored battery cell capacity at the time of manufacture. The battery cell capacity at the time of manufacture is a battery cell capacity value measured at the time of manufacture and stored in the memory unit 310. If the difference between the derived battery cell capacity and the pre-stored battery cell capacity at the time of manufacture exceeds a pre-set critical value, the control unit 308 determines that the capacity of the battery cell has deteriorated.

[0054] In addition, the control unit 308 calculates a full charge / discharge time of the battery cell using the voltage measured by the voltage measurement unit 304. If a difference between the calculated full charge / discharge time of the battery cell and the full charge / discharge time of the battery cell at the time of manufacture exceeds a preset critical value, the control unit 308 determines that the battery cell has deteriorated due to an increase in the internal resistance of the battery cell.

[0055] The storage unit 310 stores identification information (ID) of the battery cells to which the battery cell abnormality determination devices are respectively connected. The storage unit 310 also stores the initial production capacity of the battery cells. The initial production capacity is the capacity of the battery cells at the time of shipping. The storage unit 310 may also store a capacity table based on the current of the battery cells at the time of production or a capacity table based on the voltage of the battery cells. The storage unit 310 also stores information on the time to reach full charge / discharge of the battery cells at the time of production.

[0056] The communication unit 312 may transmit a signal indicating a battery cell abnormality, such as a battery cell capacity degradation signal or a battery cell internal resistance increase signal, along with the identification information of the battery cell to an external device, for example, a battery management system connected to the battery module, under the control of the control unit 308. The battery cell abnormality may be determined when a difference between the capacity of the battery cell calculated by the control unit 308 and the pre-stored capacity of the battery cell at the time of manufacture exceeds a preset critical value, thereby determining that the capacity of the battery cell has deteriorated. The battery cell abnormality may also be determined when a difference between the full charge / discharge time of the battery cell calculated by the control unit 308 and the full charge / discharge time of the battery cell at the time of manufacture exceeds a preset critical value, thereby determining that the battery cell has deteriorated due to an increase in the internal resistance of the battery cell.

[0057] 4a to 4c are diagrams illustrating a simplified implementation example of a battery cell abnormality determination device according to an embodiment of the present invention.

[0058] 4a, a voltage sensing unit is shown that is generated across the positive and negative terminals of a battery cell. The voltage sensing unit can be considered to be a component that corresponds to the voltage measurement unit 304 in the configuration of FIG. 3. The voltage sensing unit is disposed across the positive and negative terminals of the battery cell and senses the voltage of the battery cell. The voltage measured by the voltage sensing unit is transmitted to a measurement / storage circuit.

[0059] A measurement / storage circuit is disposed above the negative terminal of the battery cell, and may include components corresponding to the magnetic field measurement unit 302, the temperature measurement unit 306, the control unit 308, the memory unit 310, and the communication unit 312 in the configuration of FIG.

[0060] The voltage measured by the voltage sensing unit is transmitted to a measurement / storage circuit, and the measurement / storage circuit calculates a full charge / discharge time of the battery cell using the battery cell voltage transmitted from the control unit 308. If the difference between the calculated full charge / discharge time of the battery cell and the full charge / discharge time of the battery cell at the time of production exceeds a preset critical value, the control unit 308 determines that the battery cell has deteriorated due to an increase in the internal resistance of the battery cell.

[0061] In addition, the magnetic field measurement unit 302 of the measurement / storage circuit measures a magnetic field around the battery cell that is generated when a current flows through the battery cell. For example, the strength of the magnetic field measured by the magnetic field measurement unit 302 is received by the control unit 308, and the control unit 308 can calculate the current flowing through the battery cell in real time. Then, the current flowing through the battery cell calculated in real time can be accumulated over a certain period of time to derive the capacity of the battery cell.

[0062] The control unit 308 of the measurement / storage circuit derives the capacity of the battery cell, and if the difference between the derived capacity of the battery cell and the pre-stored capacity of the battery cell at the time of production exceeds a pre-set critical value, it is determined that the capacity of the battery cell has deteriorated.

[0063] The measurement / storage circuit may also include a thermistor capable of measuring the temperature of the battery cell. For example, the thermistor may have a configuration corresponding to the temperature measurement unit 306 of the battery cell abnormality determination device shown in FIG.

[0064] The control unit 308 may determine whether or not the capacity of the battery cell has deteriorated by reflecting the temperature of the battery cell measured by a thermistor, etc. In this case, a look-up table of the capacity change of the battery cell according to the temperature of the battery cell, which is determined in advance through an experiment, may be used.

[0065] The memory unit 310 may also be disposed in the measurement / storage circuit. The memory unit 310 stores identification information (ID) of the battery cells to which the battery cell abnormality determination devices are respectively connected. The memory unit 310 also stores the initial production capacity of the battery. The initial production capacity is the capacity of the battery cell at the time of shipment. Therefore, the memory unit 310 may store a capacity table based on the current of the battery cell at the time of production or a capacity table based on the voltage of the battery cell. The memory unit 310 also stores information on the time to reach full charge / discharge of the battery cell at the time of production.

[0066] The communication unit 312 may also be disposed in the measurement / storage circuit. When it is determined that the capacity of the battery cell has deteriorated because a difference between the capacity of the battery cell calculated by the control unit 308 and the pre-stored capacity of the battery cell at the time of manufacture exceeds a preset critical value, or when it is determined that the battery cell has deteriorated due to an increase in the internal resistance of the battery cell because a difference between the calculated full charge / discharge time of the battery cell and the full charge / discharge time of the battery cell at the time of manufacture exceeds a preset critical value, the communication unit 312 may transmit a battery cell capacity deterioration signal or a battery cell internal resistance increase signal together with identification information of the battery cell to an external device, for example, a battery management system connected to a battery module, by the control unit 308.

[0067] Referring to FIG. 4b, a magnetic field shield is shown surrounding the lower and side surfaces of the battery cell tab at a certain distance, and a PCB including circuit components corresponding to the measurement / storage circuit arranged on the upper surface of the battery cell tab is also shown.

[0068] The magnetic field shield functions to collect the magnetic field generated when current flows through the battery cell. The magnetic field generated when current flows through the battery cell and collected by the magnetic field shield is measured by the magnetic field measurement unit 302 of the measurement / storage circuit.

[0069] The magnetic field shield may be made of, for example, a nickel alloy (Ni-alloy).

[0070] Referring to FIG. 4c, a side view of a PCB including circuit components corresponding to a measurement / storage circuit disposed on the upper surface of the battery cell tab and a magnetic field shield formed to surround the lower and side surfaces of the battery cell tab at a certain distance is shown.

[0071] A circuit is formed on a PCB board attached to the upper surface of the tab of the battery cell, and the PCB board is attached to both sides of a magnetic shield surrounding the tab of the battery cell.

[0072] FIG. 5 is a flowchart of a method for determining an abnormality in a battery cell according to an embodiment of the present invention.

[0073] The magnetic field generated by the current flowing through the battery cell is collected by the magnetic field shield unit. The collected magnetic field is measured by the magnetic field measurement unit 302, and the strength of the measured magnetic field is transmitted to the control unit 308. The control unit 308, which receives the measured magnetic field strength, calculates the current flowing through the battery cell in real time using the measured magnetic field strength (S500). For example, the current of the battery cell can be indirectly calculated using the measured magnetic field according to the Biot-Savart law. For example, the control unit 308 receives the magnetic field strength measured by the magnetic field measurement unit 302 and calculates the current flowing through the battery cell in real time.

[0074] The control unit 308 calculates the capacity of the battery cell by accumulating the calculated current for a certain period of time (S502). The formula for accumulating the calculated current for a certain period of time is as follows:

[0075]

number

[0076] The control unit 308 determines whether the difference between the calculated capacity of the battery cell and the capacity of the battery cell at the time of production stored in the storage unit 310 exceeds a preset critical value (S504).

[0077] Here, the temperature measuring unit 306 may further measure the temperature of the battery cell. The temperature measuring unit 306 may be, for example, a thermistor. The battery state of charge (SOC) of the battery cell may change depending on the temperature. Therefore, when calculating the capacity of the battery cell according to the current, the capacity of the battery cell may be calculated by also referring to the temperature of the battery cell. The change in the capacity of the battery cell according to the temperature of the battery cell may be calculated using a look-up table of the capacity of the battery cell according to the temperature of the battery cell, which is determined in advance through an experiment.

[0078] When the control unit 308 determines that the difference between the calculated capacity of the battery cell and the capacity of the battery cell at the time of manufacture stored in the memory unit 310 does not exceed a preset critical value, the control unit 308 again calculates the magnetic field measurement value generated by the current flowing through the battery cell as the current value of the battery cell.

[0079] If the control unit 308 determines that the difference between the calculated capacity of the battery cell and the capacity of the battery cell at the time of production stored in the memory unit 310 exceeds a preset critical value, the control unit 308 transmits a battery cell capacity degradation notification signal to the communication unit 312 (S506).

[0080] FIG. 6 is a flowchart of a method for determining an abnormality in a battery cell according to another embodiment of the present invention.

[0081] The voltage measurement unit 304 measures the voltage of the battery cell (S600). The voltage measurement unit 304 is disposed across the negative and positive terminals of the battery cell to measure the voltage of the battery cell. The voltage of the battery cell measured by the voltage measurement unit 304 is transmitted to the control unit 308.

[0082] The control unit 308 receives the battery cell voltage measured by the voltage measurement unit 304 in real time and measures the time it takes for the battery cell to reach full charge from a fully discharged state using the received battery cell voltage. That is, the control unit 308 derives the full charge / discharge time of the battery cell (S602).

[0083] In addition, the control unit 308 compares the derived charge / discharge time of the battery cell with the pre-stored charge / discharge time of the battery cell at the time of manufacture, and determines whether the difference between the derived charge / discharge time of the battery cell and the pre-stored charge / discharge time of the battery cell at the time of manufacture exceeds a preset critical value (S604).

[0084] If the difference between the derived charge / discharge time of the battery cell and the pre-stored charge / discharge time of the battery cell at the time of production exceeds a preset critical value, the control unit 308 transmits a signal indicating an increase in the internal resistance of the battery cell to the communication unit 312 (S606).

[0085] On the other hand, if the difference between the derived charge / discharge time of the battery cell and the pre-stored charge / discharge time of the battery cell at the time of production does not exceed a preset critical value, the control unit 308 controls the voltage measurement unit 304 to measure the voltage of the battery cell.

[0086] FIG. 7 is a diagram showing the configuration of a battery cell abnormality determination device according to another embodiment of the present invention.

[0087] The battery cell abnormality determination device 700 includes a magnetic field shield unit 701 , a magnetic field measurement unit 702 , a voltage measurement unit 704 , a temperature measurement unit 706 , and a communication unit 708 .

[0088] The magnetic field shield unit 701 collects the magnetic field flowing through the battery cells in order to measure the current of each battery cell. The magnetic field shield unit 701 may be formed to surround the bottom and side surfaces of the tabs of the battery cells at a certain distance in order to accurately measure the magnetic field generated when current flows through the battery cells. The magnetic field shield unit 701 may be made of, for example, a nickel alloy.

[0089] The magnetic field measurement unit 702 measures a magnetic field generated around the battery cell when a current flows through the battery cell. The measured magnetic field can be used to indirectly calculate the current of the battery cell, for example, by the Biot-Savart law.

[0090] The voltage measuring unit 704 measures the voltage of the battery cell. Since the voltage measuring unit 704 measures the voltage of the battery cell, it is disposed across the negative terminal and the positive terminal of the battery cell.

[0091] The temperature measuring unit 706 can measure the temperature of the battery cell. The temperature measuring unit 306 can be, for example, a thermistor. Since the battery state of charge (SOC) of the battery cell can change depending on the temperature, the capacity of the battery cell can be calculated by also taking the temperature of the battery cell into consideration when calculating the capacity of the battery cell according to the current. The change in the capacity of the battery cell according to the temperature of the battery cell can be calculated using a look-up table of the capacity of the battery cell according to the temperature of the battery cell, which is determined in advance through an experiment.

[0092] The communication unit 708 transmits the magnetic field strength, voltage value, and temperature measured by the magnetic field measurement unit 702, voltage measurement unit 704, and temperature measurement unit 706 to a Battery Management System (BMS) 710. The communication unit 708 can transmit the magnetic field strength, voltage value, and temperature of the battery cell to the BMS 710 wirelessly or via a wired connection. The communication unit 708 also transmits identification information of the battery cell, the initial production capacity of the battery cell, and information on the full charge / discharge time at the time of production of the battery cell, which are stored in the memory unit 709.

[0093] The storage unit 709 stores identification information (ID) of the battery cells to which the battery cell abnormality determination devices are respectively connected. The storage unit 709 also stores the initial production capacity of the battery cells. The initial production capacity can be derived from a capacity table based on the voltage of the battery cells. Therefore, the storage unit 709 can store a capacity table based on the current of the battery cells at the time of production, or a capacity table based on the voltage of the battery cells. The storage unit 709 also stores information on the time to full charge / discharge of the battery cells at the time of production.

[0094] However, instead of the configuration of the magnetic field shield unit 701 and the magnetic field measurement unit 702, a current measurement unit that immediately measures the current of the battery cell may be used. In this case, the current value measured by the current measurement unit is transmitted to the BMS.

[0095] The communication unit 712 of the BMS 710 receives the magnetic field strength, voltage value, and temperature of a specific battery cell wirelessly or via a wired connection from the battery cell abnormality determination device 700.

[0096] The communication unit 712 transmits the received information on the magnetic field strength, voltage value, temperature, identification information of the battery cell, capacity information of the battery cell at the time of production, and full charge time of the battery cell at the time of production to the control unit 714.

[0097] The control unit 714 calculates the real-time current of the battery cell using the received magnetic field value of the battery cell. The control unit 714 accumulates the calculated battery cell current for a certain period of time to calculate the battery cell capacity. At this time, the control unit 714 may use the temperature measured by the temperature measuring unit 706 to reflect the temperature measured in the temperature measuring unit 706 in the calculation of the battery cell capacity. A look-up table of battery cell capacity changes according to the battery cell temperature, which is determined in advance through experiments, may be used.

[0098] In addition, the control unit 714 compares the derived battery cell capacity with the pre-stored capacity of the battery cell at the time of manufacture. The capacity of the battery cell at the time of manufacture is stored in the storage unit 709. If the difference between the derived battery cell capacity and the pre-stored capacity of the battery cell at the time of manufacture exceeds a preset critical value, the control unit 714 determines that the capacity of the battery cell has deteriorated.

[0099] In addition, the control unit 714 calculates a full charge / discharge time of the battery cell using the voltage measured by the voltage measurement unit 704. If a difference between the calculated full charge / discharge time of the battery cell and the full charge / discharge time of the battery cell at the time of manufacture exceeds a preset critical value, the control unit 714 determines that the battery cell has deteriorated due to an increase in the internal resistance of the battery cell.

[0100] In this embodiment, the capacity and full charge / discharge time of the battery cell at the time of production are stored in the storage unit 709, but they may also be stored in a separate storage unit (not shown) of the BMS.

[0101] Alternatively, the capacity and full charge / discharge time of the battery cell at the time of production are stored in the memory unit 709, and once the BMS receives the capacity and full charge / discharge time of the battery cell at the time of production, it can be stored together with the identification information of the battery cell and used later.

[0102] FIG. 8 is a flowchart of a method for determining an abnormality in a battery cell according to another embodiment of the present invention.

[0103] When a current flows through the battery cell, a magnetic field generated around the battery cell is measured by the magnetic field measurement unit 702 (S800). The magnetic field generated around the battery cell can be shielded by the magnetic field shield unit 701.

[0104] Further, the voltage of the battery cell is measured by the voltage determination unit 704 (S802). The voltage measurement unit 704 measures the voltage of the battery cell, and is therefore disposed across the negative and positive terminals of the battery cell.

[0105] Further, the temperature of the battery cell is measured by the temperature measuring unit 706 (S802). The temperature measuring unit 706 may be, for example, a thermistor. Since the battery state of charge (SOC) of the battery cell may change depending on the temperature, the capacity of the battery cell can be calculated by also referring to the temperature of the battery cell when calculating the capacity of the battery cell according to the current. The change in the capacity of the battery cell according to the temperature of the battery cell can be calculated using a look-up table of the capacity of the battery cell according to the temperature of the battery cell, which is determined in advance through an experiment.

[0106] The measured magnetic field strength, voltage, and temperature of the battery cell are transmitted to the BMS, along with the identification information of the battery cell, the initial production capacity of the battery cell, and the time to reach full charge / discharge at the time of production of the battery cell (S806).

[0107] FIG. 9 is a flowchart of a method for determining an abnormality in a battery cell according to another embodiment of the present invention.

[0108] The BMS 710 receives, from the battery cell abnormality determination device for each of the plurality of battery cells, the magnetic field strength, voltage, and temperature of the battery cell, as well as the identification information of the battery cell, the initial production capacity of the battery cell, and the time to reach full charge / discharge at the time of production of the battery cell (S900). The communication unit 712 of the BMS 710 can receive information from each of the battery cell abnormality determination devices wirelessly or via a wired connection.

[0109] The control unit 714 of the BMS 710 calculates the current flowing through the battery cell in real time using the received magnetic field strength (S902). For example, the current of the battery cell can be indirectly calculated using the measured magnetic field according to the Biot-Savart law.

[0110] Next, the control unit 714 calculates the capacity of the battery cell by accumulating the calculated current for a certain period of time (S904). The formula for accumulating the calculated current for a certain period of time is as follows:

[0111]

number

[0112] After calculating the capacity of the specific battery cell, the control unit 714 determines whether the difference between the calculated capacity of the battery cell and the capacity of the battery cell at the time of manufacture exceeds a preset critical value (S906).

[0113] Furthermore, since the battery state of charge (SOC) of a battery cell may change depending on the temperature, the capacity of the battery cell can be calculated by also referring to the temperature of the battery cell when calculating the capacity of the battery cell depending on the current. The change in the capacity of the battery cell depending on the temperature of the battery cell can be calculated using a look-up table of the capacity of the battery cell depending on the temperature of the battery cell, which is determined in advance by experiment.

[0114] If the control unit 714 determines that the difference between the calculated capacity of the battery cell and the capacity of the battery cell at the time of production does not exceed a preset critical value, the control unit 714 again receives information on the battery cell from the battery cell abnormality determination device in real time.

[0115] However, if the control unit 714 determines that the difference between the calculated capacity of the battery cell and the capacity of the battery cell at the time of production exceeds a preset critical value, it causes the communication unit 712 to transmit a battery cell capacity degradation notification signal to the upper controller 2 (S906).

[0116] Meanwhile, the control unit 714 also calculates a full charge / discharge time of the battery cell using the received voltage of the specific battery cell, and determines whether a difference between the calculated full charge / discharge time of the specific battery cell and the full charge / discharge time of the battery cell at the time of production exceeds a preset critical value (S908).

[0117] If the difference between the derived charge / discharge time of the battery cell and the pre-stored charge / discharge time of the battery cell at the time of production exceeds a preset critical value, the control unit 714 controls the communication unit 712 to transmit a signal indicating an increase in the internal resistance of the battery cell to the upper controller 2 (S910).

[0118] On the other hand, if the difference between the derived charge / discharge arrival time of the battery cell and the pre-stored charge / discharge arrival time of the battery cell at the time of production does not exceed a preset critical value, the control unit 308 again receives information about the battery cell from the battery cell abnormality determination device in real time.

[0119] FIG. 10 is a block diagram showing the hardware configuration of a battery management system according to an embodiment of the present invention.

[0120] The battery management system 1000 may include a microcontroller (MCU) 1010 that controls various processes and components, a memory 1040 that stores an operating system program and various programs (e.g., a battery pack abnormality diagnosis program or a battery pack temperature estimation program), an input / output interface 1030 that provides an input interface and an output interface between the battery cell module and / or the semiconductor switching element, and a communication interface 1020 that can communicate with the outside via a wired or wireless communication network. As such, the computer program according to the present invention may be stored in the memory 1040 and processed by the microcontroller 1010, thereby being embodied as a module that performs each of the functional blocks shown in FIGS. 3 and 7, for example.

[0121] References herein to "one embodiment" of the present principles, as well as various variations of such phrases, mean that the particular features, structures, characteristics, etc., associated with this embodiment are included in at least one embodiment of the present principles. Thus, the appearances of the phrase "one embodiment" and any other variations disclosed throughout this specification do not necessarily all refer to the same embodiment.

[0122] All embodiments and conditional examples disclosed throughout this specification are intended to help those skilled in the art to understand the principles and concepts of the present invention. Those skilled in the art will understand that the present invention can be embodied in modified forms without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments should be considered from an illustrative rather than a restrictive perspective. The scope of the present invention is defined by the claims, not the foregoing description, and all differences within the scope of the claims should be construed as being within the scope of the present invention.

Claims

1. A battery pack including a plurality of battery cells and an abnormality determination device that determines an abnormality in each of the plurality of battery cells, The abnormality determination device a magnetic field shield unit that separately collects magnetic fields generated by currents flowing through the battery cells; a magnetic field measurement unit that measures magnetic fields generated by currents flowing through the battery cells; a temperature measurement unit for measuring the temperature of each of the plurality of battery cells; a control unit that calculates a full charge capacity of each of the plurality of battery cells using a current calculated based on a magnetic field measured by the magnetic field measurement unit and the temperature measured by the temperature measurement unit, the control unit determines an abnormality in each of the plurality of battery cells using a full charge capacity of each of the plurality of battery cells. Battery pack.

2. The battery pack according to claim 1 , wherein the abnormality determination device further includes a storage unit that stores full charge capacities of the plurality of battery cells at the time of production.

3. 3. The battery pack of claim 2, wherein the control unit calculates a full charge capacity of each of the plurality of battery cells by accumulating the current calculated based on the magnetic field measured by the magnetic field measurement unit for a first time period.

4. 4. The battery pack of claim 2, wherein the control unit determines that the full charge capacity of each of the plurality of battery cells has deteriorated when a capacity difference between a full charge capacity of each of the plurality of battery cells and a full charge capacity at the time of manufacture of each of the plurality of battery cells exceeds a predetermined capacity difference critical value.

5. The abnormality determination device further includes a voltage measurement unit that measures the voltage of each of the plurality of battery cells, The storage unit further stores a full charge / discharge time at the time of production of each of the plurality of battery cells, the control unit calculates a full charge / discharge time for each of the plurality of battery cells using a voltage of each of the plurality of battery cells; When a time difference between the measured full charge / discharge time of each of the plurality of battery cells and the full charge / discharge time at the time of production of each of the plurality of battery cells exceeds a predetermined time difference critical value, it is determined that the internal resistance of each of the plurality of battery cells has increased. The battery pack according to any one of claims 2 to 4.

6. The battery pack according to claim 1 , wherein the magnetic field measuring unit and the magnetic field shielding unit are provided on either a negative electrode or a positive electrode of each of the plurality of battery cells.

7. The battery pack of claim 1 , wherein the battery pack is for an energy storage system (ESS) or a vehicle.

8. Measuring magnetic fields generated by currents flowing through each of the plurality of battery cells, the magnetic fields being collected separately by the magnetic field shield unit; measuring a temperature of each of the plurality of battery cells; calculating a full charge capacity of each of the plurality of battery cells by accumulating a current derived from a measured magnetic field based on the measured temperature; determining whether or not each of the plurality of battery cells has an abnormality using the calculated full charge capacities of each of the plurality of battery cells; A method for determining an abnormality in a battery cell, including:

9. measuring a voltage of each of the plurality of battery cells; Calculating a time to reach full charge / discharge for each of the plurality of battery cells using the measured voltages of each of the plurality of battery cells; determining whether a time difference between a full charge / discharge time of each of the plurality of battery cells and a full charge / discharge time at the time of production of each of the plurality of battery cells exceeds a predetermined time difference threshold value; determining that an internal resistance of each of the plurality of battery cells has increased when the time difference exceeds the time difference critical value; The method for determining an abnormality in a battery cell according to claim 8 , further comprising:

10. 10. The method of claim 8, further comprising determining that the full charge capacity of each of the battery cells has deteriorated when a capacity difference between a full charge capacity of each of the battery cells and a full charge capacity at the time of manufacture of each of the battery cells exceeds a predetermined capacity difference threshold value.

11. 11. The method of claim 9, further comprising transmitting an internal resistance increase signal or a capacity degradation signal to an external device when it is determined that the internal resistance of each of the battery cells has increased or the full charge capacity of each of the battery cells has deteriorated.

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