Battery diagnostic device, battery diagnostic method, battery pack, and automobile

Abstract

A battery diagnostic device according to an embodiment of the present invention includes a voltage sensing circuit configured to generate a voltage signal indicating a cell voltage of a battery cell, a recording medium configured to record time-series data of the cell voltage, and a control circuit operatively coupled to the voltage sensing circuit and the recording medium, wherein the control circuit is configured to (i) receive the voltage signal and record the time-series data of the cell voltage on the recording medium, (ii) determine first and second cell voltage slopes for different first and second time intervals based on the time-series data, (iii) determine an average slope of the cell voltage for a third time interval between the first and second time intervals based on the time-series data, and (iv) set the first and second cell voltage slopes as boundary conditions of a normal slope range, and diagnose the battery cell as having a voltage abnormality if the condition that the average slope of the cell voltage falls outside the normal slope range is met.

Description

[Technical Field]

[0001] The present invention relates to a technique for diagnosing voltage abnormalities in a battery.

[0002] This application claims priority based on Korean Patent Application No. 10-2022-011733, filed on September 16, 2022, the entire contents of which are incorporated herein by reference in their entirety in the specification and drawings thereof. [Background technology]

[0003] In recent years, as demand for portable electronic products such as laptops, video cameras, and mobile phones has grown rapidly and the development of electric vehicles, energy storage systems, robots, and artificial satellites has gained momentum, active research has been conducted into high-performance batteries that can be repeatedly charged and discharged.

[0004] Currently commercially available batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium batteries. Among them, lithium batteries are attracting attention due to their advantages of being able to be freely charged and discharged since they have almost no memory effect compared to nickel-based batteries, a very low self-discharge rate, and a high energy density.

[0005] In recent years, energy storage systems and electric vehicles that require high voltages have become widespread, and as a result, there is an increasing need for diagnostic technology that can accurately detect voltage abnormalities in each of the multiple battery cells connected in series within a battery pack.

[0006] Abnormal battery cell voltage refers to a fault state in which the cell voltage drops and / or rises abnormally due to an internal short circuit, an external short circuit, a failure of the voltage sensing line, a poor connection with the charge / discharge line, or the like.

[0007] Previously, a simple method was used to diagnose battery cell voltage abnormalities by determining whether the difference between cell voltages measured at two different points in time exceeded a reference value. This method has the advantage of not requiring a high-performance processor because it does not require a large amount of data calculations.

[0008] However, since the voltage of a battery cell also depends on the temperature, current, and / or SOH (State of Health), it is difficult to accurately diagnose an abnormal voltage of a battery cell by simply comparing the voltage difference of the battery cell measured at different times with a reference value.

[0009] In addition, even if the voltage difference between battery cells is below the reference value, if the voltage gradient of the battery cells shows abnormal behavior, for example, if lithium plating occurs at the negative electrode of a lithium battery, there is a limitation in that the cell voltage abnormality cannot be detected. Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention has been made to solve the above-mentioned problems, and aims to provide a battery diagnostic device, a battery diagnostic method, a battery pack, and a vehicle for efficiently and accurately diagnosing voltage abnormalities in battery cells using the slope of voltage change of the battery cells.

[0011] Other objects and advantages of the present invention can be understood from the following description and become more apparent from the embodiments of the present invention, and can be realized by the means and combinations thereof as set forth in the claims. [Means for solving the problem]

[0012] In order to achieve the above object, a battery diagnostic device according to one aspect of the present invention includes a voltage sensing circuit configured to generate a voltage signal indicative of a cell voltage of a battery cell, a recording medium configured to record time-series data of the cell voltage, and a control circuit operably coupled to the voltage sensing circuit and the recording medium.

[0013] The control circuit may be configured to (i) receive the voltage signal and record time series data of the cell voltage on a recording medium, (ii) determine a first cell voltage slope and a second cell voltage slope for different first and second time intervals based on the time series data, respectively, (iii) determine an average cell voltage slope for a third time interval between the first and second time intervals based on the time series data, and (iv) set the first cell voltage slope and the second cell voltage slope as boundary conditions of a normal slope range, and diagnose the battery cell as having a voltage abnormality if the condition that the average cell voltage slope falls outside the normal slope range is met.

[0014] The duration of the third time interval may be greater than the duration of the first time interval and the duration of the second time interval.

[0015] The duration of the first time interval may be substantially the same as the duration of the second time interval.

[0016] In one embodiment, when the cell voltages constituting the time-series data show a substantially continuously decreasing pattern, the control circuit may be configured to diagnose the battery cell as having a voltage abnormality if the first cell voltage slope, the second cell voltage slope, and the average slope of the cell voltages do not satisfy the inequality condition of Equation 1 below:

[0017] [Formula 1] Inequality: 1st cell voltage slope < average cell voltage slope < 2nd cell voltage slope

[0018] In another embodiment, the control circuit may be configured to diagnose a battery cell as having a voltage abnormality if the first cell voltage slope, the second cell voltage slope, and the average slope of the cell voltages do not satisfy the inequality condition of Equation 2 below when the cell voltages constituting the time-series data show a substantially continuously increasing pattern.

[0019] [Formula 2] Inequality: 1st cell voltage slope > average cell voltage slope > 2nd cell voltage slope

[0020] In yet another embodiment, the control circuit may be configured to diagnose the battery cell as having a voltage abnormality if both the inequality condition and the equality condition of the following Equation 3 are not satisfied when the operating state of the battery cell is switched from the charging state to the no-load state:

[0021] [Formula 3] Inequality: 1st cell voltage slope < average slope < 2nd cell voltage slope Equation: 1st cell voltage slope = average slope = 2nd cell voltage slope

[0022] In yet another embodiment, the control circuit may be configured to diagnose the battery cell as having a voltage abnormality if both the inequality condition and the equality condition of the following Equation 4 are not satisfied when the operating state of the battery cell is switched from the discharge state to the no-load state:

[0023] [Formula 4] Inequality: 1st cell voltage slope > average slope > 2nd cell voltage slope Equation: 1st cell voltage slope = average slope = 2nd cell voltage slope

[0024] The control circuit may be configured to update a voltage abnormality detection count for the battery cell when the battery cell is diagnosed with a voltage abnormality.

[0025] The battery diagnostic device may further include a display operably coupled to the control circuit, and the control circuit may be configured to output, via the display, a result of diagnosing a battery cell in which a voltage abnormality has occurred, the battery cell satisfying a condition that the voltage abnormality detection count is equal to or greater than a reference value.

[0026] The battery diagnostic device may further include an interface unit operably coupled to the control circuit and configured to facilitate communication with an external device, wherein the control circuit may be configured to transmit a result of diagnosing a battery cell in which a voltage abnormality has occurred, the battery cell satisfying a condition that the voltage abnormality detection count is equal to or greater than a reference value, to the external device via the interface unit.

[0027] In order to achieve the above object, a battery diagnostic method according to another aspect of the present invention includes a first step of receiving an input of a voltage signal indicating a cell voltage of a battery cell from a voltage sensing circuit and recording time series data of the cell voltage on a recording medium; a second step of determining a first cell voltage slope in a first time interval based on the time series data; a third step of determining a second cell voltage slope in a second time interval after the first time interval based on the time series data; a fourth step of determining an average cell voltage slope in a third time interval between the first time interval and the second time interval based on the time series data; a fifth step of setting the first cell voltage slope and the second cell voltage slope as boundary conditions of a normal slope range; and a sixth step of diagnosing the battery cell as having a voltage abnormality if the condition that the average cell voltage slope is outside the normal slope range is met.

[0028] The above object is also achieved by a battery pack including the above-described battery diagnostic device and a vehicle including the battery pack. [Effects of the Invention]

[0029] According to one aspect of the present invention, a battery cell with an abnormal voltage can be identified through a simple calculation using the slope of the cell voltage calculated in the first time interval and the second time interval, and the average slope of the cell voltage determined between the first time interval and the second time interval.

[0030] Furthermore, according to one aspect of the present invention, the calculation method used for diagnosing the battery is not complicated, so a high-spec processor is not required.

[0031] Furthermore, according to one aspect of the present invention, battery cells exhibiting abnormal voltage behavior can be reliably identified even if the difference between voltages measured at different times is not large.

[0032] The effects of the present invention are not limited to those described above, and other effects of the present invention not mentioned above will be clearly understood by those skilled in the art from the description of the claims.

[0033] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention, serve to further understand the technical concept of the present invention. Therefore, the present invention should not be interpreted as being limited to only the matters described in the drawings. [Brief explanation of the drawings]

[0034] [Figure 1] 1 is a diagram illustrating an exemplary configuration of an electric vehicle according to an embodiment of the present invention; [Figure 2a] 10 is a diagram illustrating a first time interval T1, a second time interval T2, and a third time interval T3 according to an embodiment of the present invention in time series data of cell voltages processed in a first diagnostic cycle. FIG. [Figure 2b] FIG. 10 is a diagram illustrating time-series data of cell voltages processed in a second diagnostic cycle, for a first time interval T1, a second time interval T2, and a third time interval T3 according to an embodiment of the present invention. [Figure 2c]FIG. 10 is a diagram illustrating a first time interval T1, a second time interval T2, and a third time interval T3 according to an embodiment of the present invention in time-series data of cell voltages processed in an arbitrary m-th diagnostic cycle. [Figure 3a] 4 is a graph showing an example of time-series data of cell voltages of battery cells with normal voltages in an embodiment of the present invention; [Figure 3b] 4 is a graph showing an example of time-series data of a cell voltage of a battery cell in which a voltage abnormality has occurred in an embodiment of the present invention. [Figure 4a] 10 is a graph showing an example of time-series data of cell voltages of battery cells having normal voltages in accordance with another embodiment of the present invention; [Figure 4b] 10 is a graph showing an example of time-series data on the cell voltage of a battery cell in which a voltage abnormality has occurred in another embodiment of the present invention. [Figure 5] 1 is a flow chart illustrating an exemplary battery diagnostic method according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0035] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms and phrases used in the specification and claims should not be construed as being limited to their ordinary and dictionary meanings, but should be construed as having meanings and concepts corresponding to the technical ideas of the present invention, in accordance with the principle that the inventors themselves can appropriately define the concepts of terms in order to best describe the invention.

[0036] Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and that there may be various equivalents and modifications that can be substituted therefor at the time of this application.

[0037] Terms including ordinal numbers such as "first," "second," etc. are used to distinguish one of various components from other components, and do not limit the components.

[0038] Throughout the specification, when a part "includes" a certain element, this does not exclude other elements and means that it may further include other elements unless otherwise specified. Furthermore, terms such as "controller" in the specification refer to a unit that processes at least one function or operation, and may be embodied in hardware, software, or a combination of hardware and software.

[0039] Furthermore, throughout this specification, when a part is referred to as being "connected" to another part, this includes not only a "direct connection" but also an "indirect connection" via other elements.

[0040] FIG. 1 is a diagram showing an example of the configuration of a vehicle according to an embodiment of the present invention.

[0041] Referring to FIG. 1, an automobile 1 includes a battery pack B, an inverter 3, an electric motor 4, and a vehicle controller 5.

[0042] The automobile 1 refers to a vehicle that is driven by a motor using electric energy provided by a battery pack B. As an example, the automobile 1 may be an electric automobile, a plug-in hybrid automobile, or a hybrid automobile.

[0043] The battery pack B includes a cell group CG, a switch 6, and a battery management system 100.

[0044] The cell group CG can be coupled to the inverter 3 through a pair of power supply terminals provided on the battery pack B. The cell group CG is made up of a plurality of battery cells BC1 to BC2 connected in series. N (N is a natural number greater than or equal to 2) for each battery cell BC iThe type of battery is not particularly limited as long as it can be repeatedly charged and discharged, such as a lithium-ion battery cell. i is an index for identifying the battery cell. i is a natural number ranging from 1 to N.

[0045] The switch 6 is connected in series with the cell group CG. The switch 6 is provided in a current path for charging and discharging the cell group CG. The switch 6 is controlled to be turned on and off in response to a switching signal from the battery management system 100. The switch 6 may be a mechanical relay that is turned on and off by the magnetic force of a coil, or may be a semiconductor switch such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor).

[0046] The inverter 3 is provided to convert DC current from the cell group CG into AC current in response to commands from the battery management system 100 or the vehicle controller 5. The electric motor 4 may be, for example, a three-phase AC motor. The electric motor 4 is driven by AC power supplied from the inverter 3.

[0047] The battery management system 100 is provided to take charge of overall control related to charging and discharging of the cell group CG during operation of the automobile 1. Here, operation of the automobile 1 may include moving the automobile 1, parking, waiting at traffic lights, etc.

[0048] The battery management system 100 includes a battery diagnostic device 200. The battery management system 100 may further include at least one of a current sensor 310, a temperature sensor 320, and an interface unit 330.

[0049] The battery diagnostic device 200 measures the temperature of the battery cells BC1 to BC2 while the automobile 1 is running. N The battery diagnostic device 200 includes a voltage sensing circuit 210 and a control circuit 220, which are provided to diagnose individual voltage abnormalities.

[0050] The voltage sensing circuit 210 senses the voltages of the plurality of battery cells BC1 to BC2 through a plurality of voltage sensing lines. N The voltage sensing circuit 210 senses the voltage of each battery cell BC at regular time intervals while the vehicle 1 is running. i and generating a voltage signal indicative of the measured cell voltage. The voltage sensing circuit 210 may include a typical voltage measurement circuit known in the art. The voltage measurement circuit may include a multiplexing circuit that can sequentially select battery cells to be measured at time intervals, a filter circuit that removes noise from the voltage measurement signal, an amplifier circuit that amplifies the voltage measurement signal, and the like.

[0051] The current sensor 310 is connected in series to the cell group CG through a current path. The current sensor 310 is configured to detect the battery current flowing through the cell group CG at regular time intervals while the vehicle 1 is running and generate a current signal indicative of the detected battery current. The current sensor 310 may be a conventional sensor known in the art, such as a sense resistor or a Hall sensor. The current flowing through the cell group CG may be a charging current or a discharging current.

[0052] The temperature sensor 320 is configured to detect the temperature of the cell group CG at regular time intervals while the automobile 1 is running and generate a temperature signal indicative of the detected temperature. The temperature sensor 320 may be a conventional sensor known in the art, such as a thermocouple.

[0053] The control circuitry 220 may be implemented in hardware using at least one of application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), microprocessors, and other electrical units for performing functions.

[0054] The control circuit 220 may include a recording medium 221. The recording medium 221 may be in the form of at least one of a flash memory, a hard disk, a solid state disk (SSD), a solid disk drive (SDD), a multimedia microcard, a random access memory (RAM), a static RAM (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), and a programmable read-only memory (PROM). The recording medium 221 may record data and programs required for the arithmetic operations performed by the control circuit 220. The recording medium 221 may record data indicating the results of the arithmetic operations performed by the control circuit 220, such as diagnostic results.

[0055] The control circuit 220 may be operatively coupled to the voltage sensing circuit 210, the temperature sensor 320, the current sensor 310, the interface unit 330, and / or the switch 6. The control circuit 220 may collect sensing signals from the voltage sensing circuit 210, the current sensor 310, and the temperature sensor 320 at regular time intervals while the automobile 1 is running. The sensing signals include voltage signals, current signals, and / or temperature signals. The sensing signals may be synchronized signals. The control circuit 220 may convert the voltage signals, current signals, and / or temperature signals into digital data and accumulate and record them in the recording medium 221 to generate time-series data regarding the voltage, current, and / or temperature of the battery cells. Thus, the recording medium 221 may store the voltage, current, and / or temperature signals of each battery cell BC. i Time series data regarding the cell voltage, the current flowing through battery pack B, and the temperature can be accumulated and recorded.

[0056] The control circuit 220 can identify whether the battery cell is being charged, discharged, or in an unloaded state by referring to the magnitude and sign of the current measured through the current sensor 310.

[0057] Specifically, the control circuit 220 may identify the battery cell as being in an unloaded state when the magnitude of the current is 0. The control circuit 220 may also identify the battery cell as being discharging when the magnitude of the current is greater than 0 and the sign of the current value is positive. The control circuit 220 may also identify the battery cell as being charging when the magnitude of the current is greater than 0 and the sign of the current value is negative.

[0058] The interface unit 330 may include a communication circuit configured to support wired or wireless communication between the control circuit 220 and the vehicle controller 5 (e.g., an electronic control unit (ECU)). The wired communication may be, for example, a Controller Area Network (CAN) communication, and the wireless communication may be, for example, ZigBee (registered trademark) or Bluetooth (registered trademark) communication. Of course, the type of communication protocol is not particularly limited as long as it supports wired or wireless communication between the control circuit 220 and the vehicle controller 5.

[0059] The interface unit 330 may be coupled to an output device 331 that provides information received from the vehicle controller 5 and / or the control circuit 220 in a form that can be recognized by a user. The output device 331 may include a display 331a and a speaker 331b. The vehicle controller 5 may control the inverter 3 based on battery information (e.g., voltage, current, temperature, SOC (State of Charge)) collected through communication with the battery management system 100.

[0060] The control circuit 220 detects the voltage of each battery cell BC measured by the voltage sensing circuit 210 while the automobile 1 is running. i The time series data of the cell voltage can be used to diagnose whether the battery cell has a voltage abnormality.

[0061] Specifically, the control circuit 220 controls each battery cell BC i A first cell voltage slope is determined in a first time interval based on time series data for the cell voltage.

[0062] In addition, the control circuit 220 controls each battery cell BC i A second cell voltage slope is determined in a second time interval that is after the first time interval based on time series data for the voltage of the second cell.

[0063] In addition, the control circuit 220 controls each battery cell BC iBased on the time series data for the voltage, an average slope of the cell voltage is determined in a third time interval between the first time interval and the second time interval.

[0064] In addition, the control circuit 220 can be configured to set the first cell voltage slope and the second cell voltage slope as boundary conditions of a normal slope range, and diagnose the battery cell as having a voltage abnormality if the condition that the average slope of the cell voltage falls outside the normal slope range is met.

[0065] 2a to 2c are diagrams showing the first time interval T1, the second time interval T2, and the third time interval T3 according to an embodiment of the present invention, respectively, in the time series data of cell voltages processed in the first diagnostic cycle, the second diagnostic cycle, and the mth diagnostic cycle.

[0066] First, the i-th battery cell BC i The number of cell voltages included in the time series data for the cell voltage is n, the cell voltage measurement period is Δt, the length of the third time section is p*Δt, and the kth measurement time point t k The cell voltage measured at V i,k Let's define it as follows.

[0067] Δt can be from several tens of milliseconds to several seconds. p is a natural number and can be from several tens to several thousands. Of course, the present invention is not limited by the magnitudes of Δt and p.

[0068] Referring to FIG. 2a, in the first diagnostic cycle, the first time interval is from t1 to t2, and the second time interval is from t 2+p ~t 2+p+1 The third time interval is t2 to t 2+p is.

[0069] The time span of the third time section (t2 to t 2+p ) is the time duration (t1 to t2) of the first time interval and the time duration (t 2+p ~t 2+p+1 ) is significantly larger than

[0070] For example, when p is 1000, the first time interval is from t1 to t2, and the second time interval is from t 1002 ~t 1003 The third time interval is t2 to t 1002 It could be.

[0071] In the first time interval, the slope of the first cell voltage is (V i,2 -V i,1 ) / Δt.

[0072] In the second time interval, the second cell voltage slope is (V i,1003 -V i,1002 ) / Δt.

[0073] In the third time interval, the average slope of the cell voltage is (V i,1002 -V i,2 ) / (1000×Δt).

[0074] Referring to FIG. 2b, in the second diagnostic cycle, the first time interval is from t2 to t3, and the second time interval is from t 3+p ~t 3+p+1 The third time interval is t3 to t 3+p is.

[0075] For example, when p is 1000, the first time interval is from t2 to t3, and the second time interval is from t 1003 ~t 1004 The third time interval is t3 to t 1003 It could be.

[0076] In the first time interval, the slope of the first cell voltage is (V i,3 -V i,2 ) / Δt.

[0077] In the second time interval, the second cell voltage slope is (V i,1004 -V i,1003 ) / Δt.

[0078] In the third time interval, the average slope of the cell voltage is (V i,1003 -V i,3 ) / (1000×Δt).

[0079] Referring to FIG. 2c, in any m-th (m is a natural number equal to or less than “np−2”) diagnostic cycle, the first time interval is t m ~t m+1 and the second time interval is t m+1+p ~t m+1+p and the third time interval is t m+1 ~t m+1+p is.

[0080] For example, when p is 1000, the first time interval is t m ~t m+1 and the second time interval is t m+1+1000 ~t m+1+1000+1 and the third time interval is t m+1 ~t m+1+1000 It could be.

[0081] In the first time interval, the slope of the first cell voltage is (V i,m+1 -V i,m ) / Δt.

[0082] In the second time interval, the second cell voltage slope is (V i,m+1+1000+1 -V i,m+1+1000 ) / Δt.

[0083] In the third time interval, the average slope of the cell voltage is (V i,m+1+1000 -V i,m+1 ) / (1000×Δt).

[0084] 3a and 3b are graphs showing an example of time-series data of cell voltages of a battery cell with a normal voltage and a battery cell with a voltage abnormality in accordance with an embodiment of the present invention.

[0085] 3a and 3b show an example of time series data of cell voltage as the cell voltage decreases over time. The changes in cell voltage in FIGS. 3a and 3b may occur when the battery cell is discharging or when the battery cell is switched from a charging state to an unloaded state. An unloaded state refers to a state in which the battery cell is not charging or discharging. When the battery cell is switched from a charging state to an unloaded state, the IR voltage becomes zero, and the cell voltage decreases to the voltage in the stabilization state. The cell voltage decreases rapidly at the beginning of the unloaded state, and after a certain amount of time has passed, the cell voltage gradually decreases to the voltage in the stabilization state. The cell voltage in the stabilization state corresponds to the open circuit voltage.

[0086] 3a, the cell voltage of a battery cell with a normal voltage decreases over time without exhibiting any particular behavior in the cell voltage slope. Therefore, in the cell voltage time series data section in which the cell voltage gradually decreases, the first cell voltage slope r1 determined in the first time section T1, the second cell voltage slope r2 determined in the second time section T2, and the average cell voltage slope r1 determined in the third time section T3 are av satisfies the condition of the following inequality 1. For reference, r1, r2 and r av is a negative number, the smaller the absolute value, the larger the cell voltage gradient.

[0087] <Inequalities 1> First cell voltage gradient r1<average cell voltage gradient r av <Second cell voltage gradient r2

[0088] Referring to Figure 3b, a battery cell experiencing a voltage abnormality exhibits anomalous behavior in the cell voltage slope. For example, if the battery cell is a lithium-ion battery and lithium plating occurs at the negative electrode, the cell voltage slope exhibits anomalous behavior (see dotted circle). That is, a section where the cell voltage slope increases appears as it gradually decreases. Therefore, if abnormal behavior in the cell voltage slope occurs in the second time section T2, the condition of Inequality 1 described above cannot be satisfied.

[0089] That is, the first cell voltage gradient r1 determined in the first time interval T1, the second cell voltage gradient r2 determined in the second time interval T2, and the average gradient r of the cell voltage determined in the third time interval T3 are av cannot satisfy the condition of inequality 1 above, and the average slope of the cell voltage r av falls outside the normal slope range defined by the first cell voltage slope r1 and the second cell voltage slope r1, and satisfies the condition of the following inequality 2.

[0090] <Inequalities 2> Second cell voltage gradient r2<First cell voltage gradient r1<Average cell voltage gradient r av

[0091] If the control circuit 220 detects a second time period T2 in which inequality 2 is satisfied in any diagnostic cycle for the cell voltage time series data of the battery cell, it records the time when the voltage abnormality was detected in the recording medium 221 and increments the voltage abnormality detection count by 1.

[0092] Furthermore, if the voltage abnormality detection count exceeds a reference value during the analysis of the time-series data of the cell voltage according to the above-described method, the control circuit 220 diagnoses the corresponding battery cell as having a voltage abnormality.

[0093] The reference value may have a value of 1 or more. The reference value may be appropriately determined taking into consideration diagnostic sensitivity. For example, in applications requiring high diagnostic sensitivity, the reference value may be set to 1 to 3. For other examples, in applications requiring normal diagnostic sensitivity, the reference value may be set to 4 or more.

[0094] When the battery cell to be diagnosed is diagnosed as having an abnormal voltage, the control circuit 220 can output the diagnosis result through the output device 331.

[0095] For example, the control circuit 220 may visually output a message indicating that a battery cell in the battery pack B has a voltage abnormality through a graphical user interface via the display 331a connected to the interface unit 330.

[0096] When the battery diagnostic device 200 of the present invention is included in a battery pack B of an automobile 1, the display 331a may be a vehicle display panel provided in the automobile 1. As another example, when the battery diagnostic device 200 of the present invention is included in a diagnostic system (not shown), the display 331a may be a display panel provided in the diagnostic system.

[0097] As another example, the control circuit 220 may audibly output a message through the speaker 331b connected to the interface unit 330 indicating that a battery cell in the battery pack B has a voltage abnormality.

[0098] 4a and 4b are graphs showing an example of time-series data of cell voltages of a battery cell with a normal voltage and a battery cell with a voltage abnormality in another embodiment of the present invention.

[0099] 4a and 4b show an example of time series data of cell voltage as it increases over time. The changes in cell voltage in FIGS. 4a and 4b may occur when a battery cell is being charged or when the battery cell is switched from a discharged state to a no-load state. When a battery cell is switched from a discharged state to a no-load state, the IR voltage becomes zero, and the cell voltage increases to the voltage in the stabilized state. The cell voltage increases quickly at the beginning of the no-load state, and after a certain amount of time has passed, the cell voltage gradually increases to the voltage in the stabilized state. The cell voltage in the stabilized state corresponds to the open circuit voltage.

[0100] 4a, the cell voltage of a battery cell with a normal voltage increases over time without exhibiting any particular behavior in the cell voltage slope. Therefore, in the cell voltage time series data section in which the cell voltage gradually increases, the first cell voltage slope r1 determined in the first time section T1, the second cell voltage slope r2 determined in the second time section T2, and the average cell voltage slope r1 determined in the third time section T3 are av satisfies the following inequality 3. For reference, r1, r2 and r av is a positive number, the larger the absolute value, the larger the cell voltage gradient.

[0101] <Inequality 3> First cell voltage gradient r1>Average cell voltage gradient r av >Second cell voltage gradient r2

[0102] Referring to Figure 4b, a battery cell experiencing a voltage abnormality exhibits an anomalous behavior in the cell voltage slope. For example, if the battery cell is a lithium-ion battery, the voltage slope exhibits anomalous behavior if a disconnection occurs in the negative electrode tab or lithium plating occurs in the negative electrode. As a result, a period in which the magnitude of the cell voltage slope increases after gradually decreasing appears. Therefore, if the cell voltage slope exhibits abnormal behavior in the second time period T2, the condition of Inequality 3 described above cannot be satisfied.

[0103] That is, the first cell voltage gradient r1 determined in the first time interval T1, the second cell voltage gradient r2 determined in the second time interval T2, and the average gradient r of the cell voltage determined in the third time interval T3 are av cannot satisfy the above inequality 3, and the average slope of the cell voltage r av falls outside the normal slope range defined by the first cell voltage slope r1 and the second cell voltage slope r1 and satisfies the following inequality 4.

[0104] <Inequality 4> Average slope of cell voltage r av <1st cell voltage gradient r1<2nd cell voltage gradient r2

[0105] If the control circuit 220 detects a second time period T2 in which inequality 4 is satisfied in any diagnostic cycle of the cell voltage time series data, it records the time when the voltage abnormality was detected in the recording medium 221 and increments the voltage abnormality detection count by 1.

[0106] The control circuit 220 may also determine that the corresponding battery cell has a voltage abnormality if the voltage abnormality detection count is equal to or greater than a reference value during the process of analyzing the time-series data of the cell voltage according to the above-described method.

[0107] The control circuit 220 can also output the diagnosis result through the output device 331 when it is determined that the battery cell to be diagnosed has an abnormal voltage.

[0108] For example, the control circuit 220 may visually output a message indicating that a battery cell in the battery pack B has a voltage abnormality through a graphical user interface via the display 331a connected to the interface unit 330.

[0109] When the battery diagnostic device 200 of the present invention is included in a battery pack B of an automobile 1, the display 331a may be a vehicle display panel provided in the automobile 1. As another example, when the battery diagnostic device 200 of the present invention is included in a diagnostic system (not shown), the display 331a may be a display panel provided in the diagnostic system.

[0110] As another example, the control circuit 220 may audibly output a message through the speaker 331b connected to the interface unit 330 indicating that a battery cell in the battery pack B has a voltage abnormality.

[0111] Meanwhile, when the operating state of the battery cell to be diagnosed is switched from a charging state to a no-load state, if neither Inequality 1 nor Equation 1 below is satisfied, the control circuit 220 may diagnose the battery cell as having a voltage abnormality. Inequality 1 corresponds to the above-mentioned inequality, and Equation 1 corresponds to an additional condition for increasing the accuracy of diagnosis even when the cell voltage of the battery cell is substantially reduced to the regulated voltage (i.e., open-circuit voltage).

[0112] <Inequalities 1> First cell voltage gradient r1<average gradient r av <Second cell voltage gradient r2 <Equation 1> First cell voltage gradient r1 = average gradient r av = Second cell voltage gradient r2

[0113] Similarly, when the operating state of the battery cell to be diagnosed is switched from a discharge state to a no-load state, if neither of the following inequalities 3 and 2 is satisfied, the control circuit 220 may diagnose the battery cell as having a voltage abnormality. Inequality 3 corresponds to the above-mentioned inequalities, and Equation 2 corresponds to an additional condition for increasing the diagnostic accuracy even if the cell voltage of the battery cell substantially increases to the regulated voltage (i.e., open-circuit voltage).

[0114] <Inequality 3> First cell voltage gradient r1>average gradient r av >Second cell voltage gradient r2 <Equation 2> First cell voltage gradient r1 = average gradient r av = Second cell voltage gradient r2

[0115] The control circuit 220 may periodically execute the above-described diagnostic logic for the abnormal voltage of the battery cell on all the battery cells. In addition, when executing the diagnostic logic on all the battery cells, the control circuit 220 may independently execute the diagnostic logic for each battery cell according to a predetermined order.

[0116] The control circuit 220 may also execute the above-described diagnostic logic for voltage abnormalities of the battery cells in real time in conjunction with the measurement of the cell voltages before acquiring time-series data for the preset n cell voltages.

[0117] Specifically, referring to FIG. 2a, when the diagnosis of voltage abnormality for the battery cell is started, the control circuit 220 determines the cell voltage measurement time t 2+p+1 When this time has elapsed, a first diagnostic cycle may be performed.

[0118] That is, the control circuit 220 measures the time from measurement time t1 to t 2+p+1 Using the time series data of the cell voltage measured in the first time interval T1, the first cell voltage slope r1 in the first time interval T1, the second cell voltage slope r2 in the second time interval T2, and the average slope r of the cell voltage in the third time interval T3 are calculated. av can be determined.

[0119] Also, referring to FIG. 2b, the control circuit 220 measures the cell voltage at time t 2+p+2 When time has elapsed, a second diagnostic cycle may be performed.

[0120] That is, the control circuit 220 measures the time from measurement time t2 to t 2+p+2 Using the time series data of the cell voltage measured in the first time interval T1, the first cell voltage slope r1 in the first time interval T1, the second cell voltage slope r2 in the second time interval T2, and the average slope r of the cell voltage in the third time interval T3 are calculated. av can be determined.

[0121] Also, referring to FIG. 2c, the control circuit 220 measures the cell voltage at time t m+1+p+1 When m has elapsed, any mth diagnostic cycle may be performed.

[0122] That is, the control circuit 220 controls the measurement time t m ~t m+1+p+1 Using the time series data of the cell voltage measured in the first time interval T1, the first cell voltage slope r1 in the first time interval T1, the second cell voltage slope r2 in the second time interval T2, and the average slope r of the cell voltage in the third time interval T3 are calculated.av can be determined.

[0123] The battery diagnostic device 200 according to the embodiment of the present invention may be included in the battery management system 100, a control system of a load device (not shown), or a diagnostic system installed in a maintenance center for the automobile 1 or the battery pack B.

[0124] In the present invention, the control circuit 220 may optionally include a processor, an ASIC (Application-Specific Integrated Circuit), other chipsets, logic circuits, registers, communication modems, data processing devices, etc., known in the art, to execute the various control logics described above.

[0125] Furthermore, when the control logic is embodied as software, the control circuit 220 may be replaced by a processor that executes a set of program modules. In this case, the program modules may be stored in memory and executed by the processor. The memory may be provided inside or outside the processor and may be connected to the processor by various well-known computer components. The memory may also be included in the recording medium 221. Furthermore, the memory is a general term for devices in which information is stored, regardless of the type of device, and does not refer to a specific memory device.

[0126] In addition, various control logics of the control circuit 220 may be combined, and the combined control logic may be created as a computer-readable code system and stored in a computer-readable recording medium. The type of the recording medium is not particularly limited as long as it is accessible by a processor included in a computer. For example, the recording medium may include at least one selected from the group consisting of ROM, RAM, registers, CD-ROM, magnetic tape, hard disk, floppy disk, and optical data storage device. The code system may also be distributed and stored in and executed by computers connected via a network. Functional programs, codes, and code segments for implementing the combined control logic may be easily construed by a programmer skilled in the art to which the present invention pertains.

[0127] A battery diagnostic method using the battery diagnostic device 200 of the present invention will be described in detail below. The battery diagnostic method may be performed by the battery diagnostic device 200 while the automobile 1 is in operation. The operation of the automobile 1 may include driving, stopping, or parking. The battery diagnostic method may be performed in the process of diagnosing the battery pack B at a maintenance center for the automobile 1. The battery diagnostic method may be performed while the automobile 1 is being charged at a charging station. The operation of the control circuit 220 will be described in more detail in various embodiments of the battery diagnostic method.

[0128] 5 is a flow chart illustrating an exemplary battery diagnostic method according to an embodiment of the present invention. The diagnostic method of FIG. 5 can be repeatedly executed by the control circuit 220 at predetermined diagnostic intervals.

[0129] Referring to FIG. 5, when the battery diagnosis starts, the control circuit 220 controls the voltage sensing circuit 210 to detect the voltage of each battery cell BC in step S10. i The voltage of n cells is measured repeatedly at regular intervals, and the time series data V i,kis generated and recorded on the recording medium 221. i is an index of the battery cell, and k is a natural number from 1 to n. As a result, the recording medium 221 stores the i Time series data of cell voltage V i,k is recorded and stored. Time series data V i,k The number of cell voltages that make up this is n.

[0130] Next, the control circuit 220 repeats steps S20 to S90 a preset number of times to charge each battery cell BC i Determine the voltage fault detection count for

[0131] First, in step S20, the control circuit 220 controls each battery cell BC i Time series data V for cell voltage i,k Based on this, the first cell voltage gradient r i,1 As a result, the recording medium 221 stores the battery cells BC i The slope of the first cell voltage r i,1 is recorded.

[0132] Then, in step S30, the control circuit 220 controls each battery cell BC i Time series data V for cell voltage i,k Based on this, the second time interval (t 2+p ~t 2+p+1 ) and the second cell voltage slope r i,2 As shown in FIG. 2a, the second time interval is separated from the first time interval by p×Δt. Thus, the recording medium 221 stores the voltages of the battery cells BC i The second cell voltage gradient r i,2 is recorded.

[0133] Then, in step S40, the control circuit 220 controls each battery cell BC i Time series data V for cell voltage i,k Based on this, the first time interval (t1 to t2) and the second time interval (t 2+p ~t 2+p+1) the third time interval (t2 to t 2+p ) and the average slope of the cell voltage r i,av As a result, the recording medium 221 stores the battery cells BC i The average slope of the cell voltage with respect to i,av is recorded.

[0134] Then, in step S50, the control circuit 220 controls each battery cell BC i The first cell voltage slope r determined with respect to i,1 and the second cell voltage slope r i,2 and each battery cell BC i Normal slope range for i The boundary conditions are set as follows.

[0135] Then, in step S60, the control circuit 220 controls each battery cell BC i The average slope of the cell voltage determined with respect to r i,av The battery cell BC i Normal slope range of i Battery cell BC that has become disconnected and has a voltage abnormality i * Here, the symbol "*" indicates the battery cell where the voltage abnormality occurs. In step S60, the battery cell BC where the voltage abnormality occurs is identified. i * The embodiment for identifying is as described above based on Inequality 1 to Inequality 4, Equation 1, and Equation 2.

[0136] Next, in step S70, the control circuit 220 detects the voltage abnormality in each battery cell BC i * The time when the voltage abnormality is detected is cumulatively recorded in the recording medium 221, and the battery cell BC i * The voltage abnormality detection count for the battery cell is increased by 1. Here, the symbol "*" indicates the battery cell in which the voltage abnormality is detected.

[0137] Next, in step S80, the control circuit 220 determines whether the current diagnostic cycle has reached the preset number of diagnostic cycles. i,k is n, and the first time interval and the second time interval are spaced apart by p×Δt, the preset number of diagnostic cycles is “np−2”.

[0138] If the determination in step S80 is "No," the control circuit 220 moves the process to step S90. In step S90, the control circuit 220 increments the diagnostic cycle index by 1, and returns the process to step S10. This causes the next diagnostic cycle to be performed, and steps S10 to S80 are repeated.

[0139] As shown in FIG. 2b, in the second diagnostic cycle, the first time interval T1 is changed to t2-t3, and the second time interval T2 is changed to t 2+p+1 ~t 2+p+2 The third time period T3 is changed to t3~t 2+p+1 will be changed to.

[0140] As shown in FIG. 2c, in any m-th diagnostic cycle, the first time interval T1 is t m ~t m+1 and the second time interval T2 is changed to t m+1+p ~t m+1+p+1 The third time interval T3 is changed to t m+1 ~t m+1+p will be changed to.

[0141] Steps S10 to S70 are repeated until the determination in step S80 is "Yes."

[0142] Once the diagnostic cycle is repeated a preset number of times, each battery cell BC i A process is performed in which a value assigned to the voltage abnormality detection count for the battery cell is compared with a reference value to identify a battery cell in which a voltage abnormality has occurred, and a diagnosis result is output.

[0143] Specifically, in step S100, the control circuit 220 controls each battery cell BC i The battery cell BC whose assigned voltage abnormality detection count is equal to or greater than the reference value i # Here, the symbol "#" indicates a battery cell whose voltage abnormality detection count is equal to or greater than the reference value.

[0144] If the determination in step S100 is "YES," the control circuit 220 outputs the diagnosis result visually or audibly through the output device 331 connected to the interface unit 330. The diagnosis result may include a warning message indicating that a battery cell with an abnormal voltage has occurred in the battery pack B.

[0145] As one example, the control circuit 220 may visually output the diagnostic result through the display 331a. As another example, the control circuit 220 may audibly output the diagnostic result through the speaker 331b.

[0146] Once the diagnosis results are output, the user of the automobile 1 can take the automobile 1 to a service center to more precisely diagnose the condition of the battery pack B. If a phenomenon such as lithium plating is actually confirmed in some battery cells included in the battery pack B, the battery pack B may be replaced.

[0147] Meanwhile, the control circuit 220 may transmit the diagnostic results to an external device through the interface unit 330. The external device may be the vehicle controller 5 of the automobile 1 or an on-board automobile diagnostic device or an off-board automobile diagnostic device operably coupled through the interface unit 330.

[0148] Meanwhile, the battery diagnostic method according to the present invention may be modified as follows: The control circuit 220 may execute a diagnostic cycle in real time in conjunction with measuring the cell voltages before acquiring time-series data for the preset n cell voltages.

[0149] Specifically, after starting the cell voltage measurement of each battery cell, the control circuit 220 2+p+1 When this time has elapsed, a first diagnostic cycle may be performed.

[0150] That is, referring to FIG. 2a, the control circuit 220 controls the measurement time t 2+p+1 When time has passed, measurement time points t1 to t 2+p+1 Each battery cell BC measured at i Time series data of cell voltage V i,k Steps S10 to S70 can be performed using the above.

[0151] Also, referring to FIG. 2b, the control circuit 220 measures the cell voltage at time t 2+p+2 That is, the control circuit 220 may execute a second diagnostic cycle when the measurement time t 2+p+2 When time has passed, measurement time points t2 to t 2+p+2 Each battery cell BC measured at i Time series data of cell voltage V i,k Steps S10 to S70 can be performed using the above.

[0152] Also, referring to FIG. 2c, the control circuit 220 measures the cell voltage at time t m+1+p+1 That is, the control circuit 220 may execute any m-th diagnostic cycle when the measurement time t m+1+p+1 When time has passed, the measurement time t m ~t m+1+p+1 Each battery cell BC measured at i Time series data of cell voltage V i,k Steps S10 to S70 can be performed using the above.

[0153] The execution of steps S10 to S70 may be repeated until the number of diagnostic cycles reaches a predetermined number. After the execution of steps S10 to S70 has been repeated the predetermined number of times, steps S100 and S110 may be executed substantially in the same manner as in the above-described embodiment.

[0154] According to the above-described embodiment, a battery cell in which a voltage abnormality has occurred can be identified through a simple calculation using the slope of the cell voltage calculated in the first time interval and the second time interval, and the average slope of the cell voltage determined between the first time interval and the second time interval.

[0155] Additionally, embodiments of the present invention do not require a high-spec processor because the calculations used to diagnose the battery are not complex.

[0156] Furthermore, embodiments of the present invention allow reliable identification of battery cells exhibiting abnormal voltage behavior even when the differences between voltages measured at different times are not large.

[0157] In various embodiments of the present invention, components referred to as "modules" or "circuits" should be understood as functionally divided elements, not physically divided elements. Therefore, each component may be selectively integrated with other components, or each component may be divided into subcomponents for efficient execution of control logic. However, it will be obvious to those skilled in the art that, even if components are integrated or divided, as long as the same function can be recognized, the integrated or divided components are also construed as being within the scope of the present invention.

[0158] As described above, the present invention has been described using limited embodiments and drawings, but the present invention is not limited thereto, and it goes without saying that various modifications and variations can be made by a person having ordinary knowledge in the technical field to which the present invention pertains within the technical spirit of the present invention and the equivalent scope of the claims.

[0159] Furthermore, the present invention described above is not limited to the above-described embodiments and drawings, and various substitutions, modifications, and alterations can be made by a person having ordinary knowledge in the technical field to which the present invention belongs without departing from the technical concept of the present invention. It is also possible to selectively combine all or part of each embodiment for various modifications.

Claims

1. a voltage sensing circuit configured to generate a voltage signal indicative of a cell voltage of the battery cell; a recording medium configured to record the time-series data of the cell voltage; a control circuit operatively coupled to the voltage sensing circuit and the recording medium; The control circuit (i) receiving the voltage signal and recording time-series data of the cell voltage on the recording medium; (ii) determining a first cell voltage slope and a second cell voltage slope in a first time interval and a second time interval that are different from each other based on the time series data; (iii) determining an average slope of the cell voltages for a third time interval between the first time interval and the second time interval based on the time series data; (iv) A battery diagnostic device configured to set the first cell voltage slope and the second cell voltage slope as boundary conditions of a normal slope range, and to diagnose the battery cell as having a voltage abnormality if the condition that the average slope of the cell voltage falls outside the normal slope range is met.

2. The battery diagnostic device according to claim 1 , wherein a time width of the third time interval is greater than a time width of the first time interval and a time width of the second time interval.

3. The battery diagnostic device according to claim 2 , wherein the duration of the first time interval is substantially the same as the duration of the second time interval.

4. When the cell voltages constituting the time-series data show a pattern of substantially continuous decrease, the control circuit determines whether the first cell voltage slope, the second cell voltage slope, and the average cell voltage slope satisfy the following equation 1: [Formula 1] Inequality: First cell voltage slope < average cell voltage slope < second cell voltage slope 2. The battery diagnostic device according to claim 1, wherein the battery cell is diagnosed as having an abnormal voltage if the above condition is not met.

5. When the cell voltages constituting the time-series data show a pattern of substantially continuous increase, the control circuit determines whether the first cell voltage slope, the second cell voltage slope, and the average cell voltage slope satisfy the following equation 2: [Formula 2] Inequality: First cell voltage slope > average cell voltage slope > second cell voltage slope 2. The battery diagnostic device according to claim 1, wherein the battery cell is diagnosed as having an abnormal voltage if the above condition is not met.

6. When the operating state of the battery cell is switched from the charging state to the no-load state, the control circuit calculates the following equation 3: [Formula 3] Inequality: 1st cell voltage slope < average slope < 2nd cell voltage slope Equation: 1st cell voltage slope = average slope = 2nd cell voltage slope 2. The battery diagnostic device according to claim 1, wherein the battery cell is diagnosed as having an abnormal voltage if both of the above conditions are not met.

7. When the operating state of the battery cell is switched from a discharge state to a no-load state, the control circuit calculates the voltage Vcc of the battery cell by the following equation 4: [Formula 4] Inequality: 1st cell voltage slope > average slope > 2nd cell voltage slope Equation: 1st cell voltage slope = average slope = 2nd cell voltage slope 2. The battery diagnostic device according to claim 1, wherein the battery cell is diagnosed as having an abnormal voltage if both of the above conditions are not met.

8. The battery diagnostic device according to claim 1 , wherein the control circuit is configured to update a voltage abnormality detection count when the battery cell is diagnosed as having a voltage abnormality.

9. further comprising a display operably coupled to the control circuit; 9. The battery diagnostic device according to claim 8, wherein the control circuit is configured to output, via the display, a result of diagnosing a battery cell that satisfies a condition that the voltage abnormality detection count is equal to or greater than a reference value as a battery cell in which a voltage abnormality has occurred.

10. an interface unit operatively coupled to the control circuit to facilitate communication with an external device; 9. The battery diagnostic device according to claim 8, wherein the control circuit is configured to transmit a result of diagnosing a battery cell that satisfies a condition that the voltage abnormality detection count is equal to or greater than a reference value as a battery cell in which a voltage abnormality has occurred to an external device via the interface unit.

11. A battery pack comprising the battery diagnostic device according to any one of claims 1 to 10.

12. A motor vehicle comprising the battery pack of claim 11.

13. A first step of receiving a voltage signal indicating a cell voltage of a battery cell from a voltage sensing circuit and recording time-series data of the cell voltage on a recording medium; a second step of determining a first cell voltage slope in a first time interval based on the time series data; a third step of determining a second cell voltage slope in a second time interval after the first time interval based on the time series data; a fourth step of determining an average slope of the cell voltage in a third time interval between the first time interval and the second time interval based on the time series data; a fifth step of setting the first cell voltage slope and the second cell voltage slope to boundary conditions of a normal slope range; a sixth step of diagnosing the battery cell as having an abnormal voltage if the condition that the average gradient of the cell voltage falls outside the normal gradient range is met.

14. The battery diagnosis method according to claim 13 , wherein a time width of the third time interval is greater than a time width of the first time interval and a time width of the second time interval.

15. The sixth step is When the cell voltages constituting the time series data show a substantially continuously decreasing pattern, the first cell voltage slope, the second cell voltage slope, and the average cell voltage slope are expressed by the following Equation 1: [Formula 1] Inequality: First cell voltage slope < average cell voltage slope < second cell voltage slope The battery diagnostic method according to claim 13 or 14, further comprising the step of diagnosing the battery cell as having an abnormal voltage if the condition (a) is not satisfied.

16. The sixth step is When the cell voltages constituting the time series data show a pattern of substantially continuous increase, the first cell voltage slope, the second cell voltage slope, and the average cell voltage slope are expressed by the following Equation 2: [Formula 2] Inequality: First cell voltage slope > average cell voltage slope > second cell voltage slope The battery diagnostic method according to claim 13 or 14, further comprising the step of diagnosing the battery cell as having an abnormal voltage if the condition (a) is not satisfied.

17. The sixth step is When the operating state of the battery cell is switched from a charging state to an unloaded state, the following equation 3 is satisfied: [Formula 3] Inequality: 1st cell voltage slope < average slope < 2nd cell voltage slope Equation: 1st cell voltage slope = average slope = 2nd cell voltage slope The battery diagnosis method according to claim 13 or 14, further comprising the step of diagnosing the battery cell as having an abnormal voltage if both of the above conditions are not met.

18. The sixth step is When the operating state of the battery cell is switched from a discharge state to an unloaded state, the following equation 4 is satisfied: [Formula 4] Inequality: 1st cell voltage slope > average slope > 2nd cell voltage slope Equation: 1st cell voltage slope = average slope = 2nd cell voltage slope The battery diagnosis method according to claim 13 or 14, further comprising the step of diagnosing the battery cell as having an abnormal voltage if both of the above conditions are not met.

19. The battery diagnosis method according to claim 13 or 14, further comprising updating a voltage abnormality detection count of the battery cell when the battery cell is diagnosed as having a voltage abnormality.

20. a step of diagnosing a battery cell that satisfies the condition that the voltage abnormality detection count is equal to or greater than a reference value as a battery cell in which a voltage abnormality has occurred and displaying the result on a display; or 20. The battery diagnosis method of claim 19, further comprising: diagnosing a battery cell that satisfies a condition that the voltage abnormality detection count is equal to or greater than a reference value as a battery cell in which a voltage abnormality has occurred, and transmitting the result to an external device.

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