Method and apparatus for diagnosing battery voltage measurement error

Abstract

To provide a method and an apparatus for diagnosing a voltage measurement error of a battery.SOLUTION: A method of diagnosing a voltage measurement error of a battery pack including a plurality of battery cells includes: measuring a voltage across opposite ends of each battery cell and performing cell balancing if a voltage difference between the battery cells satisfies a predetermined balancing condition; measuring a cell balancing current flowing through a cell balancing circuit directly connected to opposite ends of the battery cell for which the cell balancing is performed; and diagnosing a voltage measurement error based on a difference between a measured cell voltage and a calculated cell voltage of the battery cell, calculated based on a resistance of the cell balancing circuit and the cell balancing current.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a method and apparatus for diagnosing battery voltage measurement errors. [Background technology]

[0002] Recently, the demand for portable electronic products such as notebook computers, video cameras, and mobile phones has increased dramatically, and the development of energy storage batteries, robots, satellites, etc. has been in full swing. As a result, research on high-performance secondary batteries that can be repeatedly charged and discharged is being actively conducted.

[0003] In such a voltage measurement of a secondary battery, an erroneous voltage measurement may occur due to an abnormality in a voltage sensing circuit that measures the voltage of the secondary battery, etc. In that case, a cell balancing operation for balancing the cell voltages of a plurality of battery cells may be performed, and the erroneous voltage measurement may cause problems such as overcharging or over-discharging of the battery cells. Summary of the Invention [Problem to be solved by the invention]

[0004] The problem to be solved by the present invention is to overcome the above-mentioned problems, and to provide a method, a computer program, and an apparatus for diagnosing a battery voltage measurement error, which can effectively diagnose a battery voltage measurement error in the process of diagnosing a battery voltage measurement error.

[0005] However, such assignments are illustrative and are not intended to limit the scope of the invention. [Means for solving the problem]

[0006] As a technical means for achieving the above technical object, a method for diagnosing a voltage measurement error in a battery pack having a plurality of battery cells is provided, the method including the steps of: measuring a voltage across each battery cell; and proceeding with cell balancing if a voltage difference between the battery cells satisfies a predetermined balancing condition; measuring a cell balancing current flowing through a cell balancing circuit directly connected to both ends of the battery cell for which cell balancing is being proceeded; and diagnosing a voltage measurement error based on a difference between a calculated cell voltage of the battery cell, calculated based on the resistance of the cell balancing circuit and the cell balancing current, and the measured cell voltage.

[0007] According to one example, the step of performing the cell balancing includes the steps of measuring the voltage across each battery cell, determining a battery cell whose voltage is measured higher than the other battery cells as a balancing target when the voltage difference between the battery cells is equal to or greater than a predetermined threshold, and closing a switch provided in a cell balancing circuit having a resistor and a switch and directly connected to both ends of the battery cell determined as the cell balancing target, to perform the cell balancing.

[0008] According to another example, the step of measuring the cell balancing current may also include a step of measuring the cell balancing current flowing through a closed circuit including the battery cell in which cell balancing is being performed, a resistor provided in the cell balancing circuit, and a switch provided in the cell balancing circuit.

[0009] According to yet another example, the step of diagnosing the voltage measurement error also includes a step of obtaining a measured cell voltage by measuring the voltage value across both ends of a battery cell undergoing cell balancing, and a step of obtaining a calculated cell voltage of the battery cell undergoing cell balancing, the calculated cell voltage being calculated based on the resistance of the cell balancing circuit and the cell balancing current.

[0010] According to yet another example, the step of diagnosing the voltage measurement error also includes a step of diagnosing that there is an abnormality in the voltage measurement unit of the battery pack if the difference between the measured cell voltage and the calculated cell voltage is equal to or greater than a predetermined threshold value.

[0011] As a technical means for achieving the above technical object, a computer program stored on a recording medium is provided for using a computing device to execute the above method.

[0012] As a technical means for achieving the above technical object, there is provided a voltage measurement error diagnosis device for diagnosing a voltage measurement error in a battery pack having a plurality of battery cells, the voltage measurement device including: a voltage measurement unit electrically connected to both ends of each battery cell and measuring the voltage of each battery cell; a cell balancing circuit directly connected to both ends of each battery cell and through which a cell balancing current of each battery cell flows; a current measurement unit measuring a current flowing through the cell balancing circuit; and a processor that, based on the voltage across each battery cell, proceeds with cell balancing if a voltage difference between the battery cells satisfies a predetermined balancing condition, and diagnoses a voltage measurement error based on the difference between the measured cell voltage and a calculated cell voltage of the battery cell calculated based on the resistance of the cell balancing circuit and the cell balancing current.

[0013] According to one example, the processor may acquire a voltage across each battery cell, and if a voltage difference between the battery cells is equal to or greater than a predetermined threshold, may determine a battery cell whose voltage is measured higher than the other battery cells as a balancing target, and may close a switch provided in a cell balancing circuit having a resistor and a switch that is directly connected to both ends of the battery cell determined as a cell balancing target, thereby proceeding with cell balancing.

[0014] According to another example, the processor may obtain from the current measurement unit a value of a cell balancing current flowing through a closed circuit including a battery cell in which cell balancing is being performed, a resistor provided in the cell balancing circuit, and a switch provided in the cell balancing circuit.

[0015] According to yet another example, the processor may obtain a measured cell voltage by measuring a voltage value across both ends of a battery cell for which cell balancing is being performed, and may obtain a calculated cell voltage of the battery cell for which cell balancing is being performed, calculated based on a resistance of the cell balancing circuit and a cell balancing current.

[0016] According to yet another example, the processor may diagnose that there is an abnormality in the voltage measurement unit if the difference between the measured cell voltage and the calculated cell voltage is equal to or greater than a predetermined threshold value. Effect of the Invention

[0017] According to the present invention, there is provided a method, a computer program, and an apparatus for diagnosing a battery voltage measurement error, which can effectively diagnose a battery voltage measurement error in the process of diagnosing a battery voltage measurement error, although it goes without saying that the scope of the present invention is not limited by such effects. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a diagram illustrating a battery pack according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram illustrating a schematic of a cell balancing circuit according to an embodiment of the present invention. [Diagram 3] 1 is a diagram for explaining a voltage measurement error diagnosis method according to an embodiment of the present invention; [Figure 4] 4 is a flowchart illustrating a method for diagnosing a voltage measurement error according to an embodiment of the present invention. [Diagram 5] 1 is an exemplary diagram for explaining a method for diagnosing a voltage measurement error according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, various embodiments will be described in detail with reference to the accompanying drawings so that a person having ordinary skill in the art to which the present disclosure pertains can easily carry out the present disclosure. However, the technical idea of ​​the present disclosure may be embodied in various forms and is not limited to the embodiments described herein. In the description of the embodiments disclosed herein, if a detailed description of a related known technology is determined to obscure the gist of the technical idea of ​​the present disclosure, the detailed description of the known technology will be omitted. Identical or similar components are denoted by the same reference numerals, and duplicate descriptions thereof will be omitted.

[0020] In this specification, when an element is described as being "connected" to another element, this does not only mean that it is "directly connected" to another element, but also means that it is "indirectly connected" to another element by having another element in between. When an element "includes" another element, this does not mean that it excludes other elements in addition to the other elements, but also means that it includes other elements.

[0021] Some embodiments may be described by functional block configurations and various processing steps. Some or all of such functional blocks may be embodied by various numbers of hardware configurations and / or software configurations performing specific functions. For example, the functional blocks of the present disclosure may be embodied by one or more microprocessors or by circuit configurations for a given function. The functional blocks of the present disclosure may be embodied by various programming languages ​​or scripting languages. The functional blocks of the present disclosure may be embodied by algorithms executed in one or more processors. The functions performed by the functional blocks of the present disclosure may be performed by multiple functional blocks, or the functions performed by multiple functional blocks in the present disclosure may be performed by one functional block. In addition, the present disclosure may employ conventional techniques for electronic configuration, signal processing, and / or data processing, etc.

[0022] FIG. 1 is a diagram illustrating a battery pack according to an embodiment of the present invention.

[0023] Referring to FIG. 1, the battery pack 100 also includes a battery module 110, a processor 150, a memory 160, a voltage measuring unit 120, a current measuring unit 130, and a temperature measuring unit 140.

[0024] The battery module 110 includes a plurality of battery cells 111, which are also rechargeable secondary batteries. For example, the battery cells 111 may include at least one selected from the group consisting of a nickel-cadmium battery, a lead-acid battery, a nickel metal hydride battery (NiMH), a lithium ion battery, a lithium polymer battery, and the like.

[0025] The number and connection manner of the battery cells 111 included in the battery module 110 may be determined based on the amount of power and voltage required for the battery pack 100. Although the battery cells 111 included in the battery module 110 are illustrated as being connected in series for conceptual purposes only in FIG. 1, the battery cells 111 may be connected in parallel to each other or in series and parallel. Although the battery pack 100 is illustrated in FIG. 1 as including one battery module 110 for conceptual purposes only in FIG. 1, the battery pack 100 may include a plurality of battery modules 110 connected in series, in parallel, or in series and parallel. The battery pack 100 also includes a pair of pack terminals 101, 102 to which an electric load or a charging device may be connected.

[0026] In this specification, the battery as the target for diagnosing a voltage measurement error refers to both the battery module 110 and each of the battery cells 111 included in the battery module 110.

[0027] According to an embodiment of the present invention, the battery pack 100 also includes a switch. The switch may be coupled between the battery module 110 and one of the pack terminals 101, 102 (e.g., pack terminal 101). The switch may be controlled by the processor 150. Although not shown in FIG. 1, the battery pack 100 may further include a battery protection circuit, a fuse, a current sensor, etc.

[0028] The voltage measurement error diagnostic apparatus according to one embodiment of the present invention also includes a processor 150 and a memory 160 .

[0029] The processor 150 controls the overall operation of the device for diagnosing voltage measurement errors, and may be implemented, for example, as a processor, an application-specific integrated circuit (ASIC), or other chipset, logic circuit, register, communication modem, and / or data processing device, as known in the art, for performing the above-described operations.

[0030] The processor 150 may perform basic arithmetic, logic, and input / output operations, for example, to execute program code stored in the memory 160. The processor 150 may store data in the memory 160 or load data stored in the memory 160.

[0031] The memory 160 is a recording medium readable by the processor 150 and may include a random access memory (RAM), a read-only memory (ROM), and a permanent mass storage device such as a disk drive. An operating system (OS) and at least one program or application code may be stored in the memory 160. According to an embodiment of the present invention, a program code for diagnosing a voltage measurement error may be stored in the memory 160. Data generated by measuring at least one parameter of the battery cell 111 may be stored in the memory 160. For example, the data may include a charging / discharging current, a terminal voltage, and / or a temperature of the battery. The memory 160 may store a program code for estimating a state of charge (SOC) of the battery using data generated by measuring at least one parameter of the battery cell 111, and SOC-OCV (open circuit. voltage) data. The at least one parameter of the battery cell 111 may refer to a component or variable such as the terminal voltage of the battery cell 111, the charge / discharge current, and / or the ambient temperature.

[0032] The voltage measurement unit 120 may be configured to measure the voltage of the battery cell 111. For example, as shown in the configuration of FIG. 1, the voltage measurement unit 120 may be electrically connected to both ends of the battery module 110 and / or the battery cell 111. The voltage measurement unit 120 may also be electrically connected to the processor 150 so as to exchange electrical signals. The voltage measurement unit 120 may also measure the voltages across the battery module 110 and / or the battery cell 111 at time intervals under the control of the processor 150 and output a signal indicating the magnitude of the measured voltage to the processor 150. At this time, the processor 150 may determine the voltages of the battery module 110 and / or the battery cell 111 from the signal output from the voltage measurement unit 120. For example, the voltage measurement unit 120 may be implemented using a voltage measurement circuit commonly used in the art.

[0033] Also, the current measuring unit 130 may be configured to measure the current of the battery. For example, as shown in the configuration of Fig. 1, the current measuring unit 130 may be electrically connected to a current sensor provided on a charge / discharge path of the battery module 110 and / or the battery cell 111. Also, the current measuring unit 130 may be directly connected to both ends of each battery cell 111 and electrically connected to a current sensor provided on a cell balancing circuit through which a cell balancing current of each battery cell 111 flows.

[0034] Also, the current measuring unit 130 may be electrically connected to the processor 150 to exchange electrical signals. Also, the current measuring unit 130 may repeatedly measure the magnitude of the charging current or discharging current of the battery module 110 and / or the battery cell 111 at time intervals under the control of the processor 150, and output a signal indicating the magnitude of the measured current to the processor 150. Also, the current measuring unit 130 may output a signal indicating the magnitude of the current flowing through the cell balancing circuit to the processor 150. At this time, the processor 150 may determine the magnitude of the current from the signal output from the current measuring unit 130. For example, the current sensor may be implemented using a Hall sensor or a sense resistor commonly used in the art.

[0035] The temperature measuring unit 140 may be configured to measure the temperature of the battery. For example, as shown in the configuration of FIG. 1, the temperature measuring unit 140 may be connected to the battery module 110 and / or the battery cell 111 and may measure the temperature of the secondary battery included in the battery module 110 and / or the battery cell 111. The temperature measuring unit 140 may be electrically connected to the processor 150 so as to exchange electrical signals. The temperature measuring unit 140 may repeatedly measure the temperature of the secondary battery at time intervals and output a signal indicating the magnitude of the measured temperature to the processor 150. At this time, the processor 150 may determine the temperature of the secondary battery from the signal output from the temperature measuring unit 140. For example, the temperature measuring unit 140 may be implemented using a thermocouple commonly used in the industry.

[0036] The processor 150 may proceed with cell balancing when a voltage difference between the battery cells satisfies a predetermined balancing condition based on the voltage across each battery cell 111. The processor 150 may also diagnose a voltage measurement error based on a difference between a calculated cell voltage of the battery cell calculated based on the resistance of the cell balancing circuit and the cell balancing current, and a measured cell voltage.

[0037] FIG. 2 is a diagram illustrating a cell balancing circuit according to an embodiment of the present invention.

[0038] 2, the cell balancing circuit according to an embodiment of the present invention includes a battery cell 111, a first resistor 210, a switch 230, and a second resistor 220. As shown in FIG. 2, the cell balancing circuit is directly connected to both ends of the battery cell 111, and a cell balancing current of the battery cell 111 may flow through the cell balancing circuit. In this case, the voltage measuring unit 120 is directly connected to both ends of the battery cell 111, and may measure the voltage across the battery cell 111.

[0039] The cell balancing circuit also includes a closed circuit including the battery cell 111 for which cell balancing is to be performed, resistors (a first resistor 210 and a second resistor 220) included in the cell balancing circuit, and a switch 230 included in the cell balancing circuit.

[0040] 3 is a diagram illustrating a method for diagnosing a voltage measurement error according to an embodiment of the present invention. Also, FIG 4 is a flowchart illustrating a method for diagnosing a voltage measurement error according to an embodiment of the present invention. The method for diagnosing a voltage measurement error according to an embodiment of the present invention may be performed by the processor 150 illustrated in FIG 1.

[0041] 3 and 4, in step S110, the processor 150 measures the voltage across each battery cell, and may proceed with cell balancing if the voltage difference between the battery cells satisfies a predetermined balancing condition.

[0042] According to an embodiment of the present invention, the processor 150 may measure the voltage across each battery cell 111 using the voltage measurement unit 120 .

[0043] Furthermore, when the voltage difference between the battery cells is equal to or greater than a predetermined threshold, the processor 150 may determine that the battery cell 111 whose voltage is measured to be higher than the other battery cells is to be subjected to balancing.

[0044] In addition, the processor 150 may close the switch 230 provided in the cell balancing circuit that is directly connected to both ends of the battery cell 111 determined as the target for cell balancing and includes resistors (first resistor 210, second resistor 220) and a switch 230, thereby proceeding with cell balancing.

[0045] In step S120, the processor 150 may measure a cell balancing current flowing through a cell balancing circuit directly coupled to both ends of the battery cell 111 in which cell balancing is being performed.

[0046] According to one embodiment of the present invention, the processor 150 may measure a cell balancing current flowing through a closed circuit including the battery cell 111 undergoing cell balancing, resistors (first resistor 210, second resistor 220) provided in the cell balancing circuit, and a switch 230 provided in the cell balancing circuit.

[0047] In step S130, the processor 150 may diagnose a voltage measurement error based on the difference between the calculated cell voltage of the battery cell calculated based on the resistance (first resistor 210, second resistor 220) of the cell balancing circuit and the cell balancing current, and the measured cell voltage.

[0048] According to an embodiment of the present invention, the processor 150 may obtain a measured cell voltage by measuring a voltage value across the battery cell 111 where cell balancing is being performed.

[0049] In addition, the processor 150 may obtain a calculated cell voltage of the battery cell 111 undergoing cell balancing, the calculated cell voltage being calculated based on the resistance (first resistor 210, second resistor 220) of the cell balancing circuit and the cell balancing current.

[0050] In addition, the processor 150 according to an embodiment of the present invention may diagnose that there is an abnormality in the voltage measurement unit of the battery pack when the difference between the measured cell voltage and the calculated cell voltage is equal to or greater than a predetermined threshold. For example, when the processor 150 diagnoses a voltage measurement error, it may generate an alarm or signal to check the battery management system (BMS) of the battery pack.

[0051] 3, for example, the measured voltage of the battery cell 111 to be subjected to cell balancing among the plurality of battery cells may be 4.1 V, and the measured voltage of the remaining battery cells may be 4 V. If the balancing condition is that the voltage difference between the battery cells is 20 mV or more, the battery cell 111 whose voltage is measured as high as 4.1 V may be determined as the cell balancing target according to the balancing condition. Then, a switch 230 (e.g., a field effect transistor (FET)) included in the cell balancing circuit including the battery cell 111 to be subjected to cell balancing may be closed (FET ON), and a cell balancing current may flow in the cell balancing circuit.

[0052] For example, the cell balancing circuit may include two balancing resistors with a resistance of 15 Ω and an internal resistor of the FET with a resistance of 2 Ω. In this case, the resistance of the cell balancing circuit may indicate 32 Ω. If the cell balancing current is subsequently measured to be 125 mA, the calculated cell voltage may be calculated to be 4 V according to the formula V=I×R. In this case, the measured cell voltage of the battery cell 111 is 4.1 V, and the calculated cell voltage is 4 V, resulting in a voltage measurement error of 0.1 V.

[0053] When the difference between the measured cell voltage and the calculated cell voltage is equal to or greater than a predetermined threshold, the processor 150 may diagnose that the voltage measurement unit is abnormal. For example, when the measured cell voltage is 4.1V and the calculated cell voltage is 4V, and a voltage measurement error of 0.1V occurs, the difference is equal to or greater than a predetermined threshold (e.g., 20mV), so the processor 150 may diagnose that the voltage measurement unit is abnormal and generate an alarm. In addition, the processor 150 prevents the cell balancing operation from being performed based on the erroneously measured value.

[0054] FIG. 5 is an exemplary diagram illustrating a method for diagnosing a voltage measurement error according to an embodiment of the present invention.

[0055] 5, a circuit of a plurality of battery cells, each of which has an actual voltage of 4 V, and a voltage measuring unit connected to both ends of each battery cell is illustrated. However, the resistance and voltage values ​​illustrated in FIG. 5 are exemplary values, and the present invention is not limited thereto.

[0056] 5, if the normal parallel resistance component of each cell sensing terminal is 100 MΩ, the parallel resistance component of the 11th battery cell C11 may be as low as 90 MΩ due to microcracks in a multilayer ceramic chip capacitor (MLCC) or a change in the characteristics of a Zener diode. In this case, the measured voltage may be different from the actual voltage due to the characteristics of the voltage distribution circuit, as shown below.

[0057] The measured voltage of the twelfth battery cell C12 is 8V×100 / (100+90)=4.21V, which is different from the actual voltage of 4V. The measured voltage of the eleventh battery cell C11 is 8V×90 / (100+90)=3.79V, which is different from the actual voltage of 4V. In this case, all cells except the eleventh battery cell C11, whose measured voltage is 3.79V, will perform balancing operations, and the twelfth battery cell C12 will continue to perform balancing operations until the end and will have the lowest actual voltage of the module.

[0058] According to the present invention, the difference between the sensed voltage and the actual cell voltage calculated after the actual cell balancing operation is used to predict BMS failures, preventing cell balancing operations based on erroneously measured values, and allowing inspections to be performed during scheduled A / S dispatches, making operation efficient in terms of costs as well.

[0059] The various embodiments described above are merely examples and should not be implemented separately from one another. The embodiments described in this specification may be implemented in combination with one another.

[0060] The various embodiments described above may be embodied in the form of a computer program that can be executed by a computer through various components, and such a computer program may be recorded on a computer-readable medium. In this case, the medium may continuously store the computer-executable program or may temporarily store it for execution or download. The medium may be various recording or storage means in the form of a single or multiple hardware components combined, and is not limited to a medium directly connected to a computer system, but may be distributed on a network. Examples of the medium include magnetic media such as hard disks, floppy disks, and magnetic tapes; optical recording media such as compact disc read only memory (CD-ROM) and digital versatile disc (DVD); magneto-optical media such as floptical disks; and ROM, RAM, flash memory, etc., configured to store program instructions. Examples of other media include recording media or storage media managed by app stores that distribute applications, and sites and servers that supply or distribute various other software.

[0061] In this specification, a "module" or "module" may refer to a hardware component such as a processor or a circuit, and / or a software component executed by a hardware component such as a processor. For example, a "module" or "module" may be embodied by a software component, an object-oriented software component, a component such as a class component, and a task component, as well as a process, a function, an attribute, a procedure, a subroutine, a segment of program code, a driver, firmware, microcode, a circuit, data, a database, a data structure, a table, an array, and a variable.

[0062] The above description of the present invention is for illustrative purposes only, and a person having ordinary skill in the art to which the present invention pertains can easily understand that the present invention can be easily modified into other specific forms without changing the technical idea or essential features of the present invention. Therefore, it should be understood that the above-described embodiments are illustrative in all respects and are not limiting. For example, each component described as being single may be implemented in a distributed form, and similarly, each component described as being distributed may be implemented in a combined form.

[0063] The scope of the present invention is defined by the claims rather than the above detailed description, and all modifications and variations that fall within the meaning, scope, and equivalent concepts of the claims should be construed as being included within the scope of the present invention. [Explanation of symbols]

[0064] 100 Battery Pack 101,102 Pack terminal 110 Battery Module 111 Battery Cell 120 Voltage measurement section 130 Current measurement section 140 Temperature measurement section 150 processors 160 Memory 210 1st resistor 220 2nd resistor 230 Switch

Claims

1. 1. A method for diagnosing a voltage measurement error in a battery pack having a plurality of battery cells, comprising: measuring a voltage across each battery cell, and proceeding with cell balancing if a voltage difference between the battery cells satisfies a predetermined balancing condition; measuring a cell balancing current flowing through a cell balancing circuit directly coupled across a battery cell undergoing cell balancing; and diagnosing a voltage measurement error based on a difference between a calculated cell voltage of a battery cell calculated based on the resistance of the cell balancing circuit and the cell balancing current and a measured cell voltage.

2. The step of advancing cell balancing comprises: Measuring a voltage across each battery cell; determining a battery cell having a higher voltage than other battery cells as a balancing target when a voltage difference between the battery cells is equal to or greater than a predetermined threshold; and closing the switch provided in the cell balancing circuit, the switch being directly connected to both ends of the battery cell determined as the cell balancing target and including a resistor and a switch, to proceed with cell balancing.

3. 2. The method of claim 1, wherein the step of measuring the cell balancing current includes a step of measuring a cell balancing current flowing through a closed circuit including a battery cell undergoing cell balancing, a resistor provided in the cell balancing circuit, and a switch provided in the cell balancing circuit.

4. The step of diagnosing a voltage measurement error includes: obtaining a measured cell voltage by measuring a voltage value across a battery cell in which the cell balancing is being performed; and obtaining the calculated cell voltage of the battery cell undergoing cell balancing, the calculated cell voltage being calculated based on the resistance of the cell balancing circuit and the cell balancing current.

5. 5. The voltage measurement error diagnosis method according to claim 4, wherein the step of diagnosing the voltage measurement error includes a step of diagnosing that there is an abnormality in a voltage measurement unit of the battery pack when a difference between the measured cell voltage and the calculated cell voltage is equal to or greater than a predetermined threshold value.

6. A computer program stored on a recording medium for causing a computing device to carry out the method according to any one of claims 1 to 5.

7. 1. An apparatus for diagnosing a voltage measurement error in a battery pack having a plurality of battery cells, comprising: a voltage measuring unit electrically connected to both ends of each battery cell and measuring a voltage of each battery cell; a cell balancing circuit directly connected to both ends of each battery cell and through which a cell balancing current of each battery cell flows; a current measuring unit that measures a current flowing through the cell balancing circuit; and a processor that, when a voltage difference between the battery cells satisfies a predetermined balancing condition based on the voltage across each battery cell, proceeds with cell balancing, and diagnoses a voltage measurement error based on a difference between a calculated cell voltage of the battery cell calculated based on the resistance of the cell balancing circuit and the cell balancing current, and a measured cell voltage.

8. 8. The voltage measurement error diagnosis device of claim 7, wherein the processor acquires a voltage across each battery cell, and when a voltage difference between the battery cells is equal to or greater than a predetermined threshold, determines a battery cell whose voltage is measured higher than other battery cells as a balancing target, and closes the switch provided in the cell balancing circuit, which is directly connected to both ends of the battery cell determined as the cell balancing target and includes a resistor and a switch, to proceed with cell balancing.

9. 8. The voltage measurement error diagnosis device of claim 7, wherein the processor acquires from the current measurement unit a value of a cell balancing current flowing through a closed circuit including a battery cell undergoing cell balancing, a resistor provided in the cell balancing circuit, and a switch provided in the cell balancing circuit.

10. 10. The voltage measurement error diagnosis device of claim 9, wherein the processor acquires the measured cell voltage by measuring a voltage value across both ends of the battery cell for which the cell balancing is being performed, and acquires the calculated cell voltage of the battery cell for which the cell balancing is being performed, the calculated cell voltage being calculated based on a resistance of the cell balancing circuit and the cell balancing current.

11. 11. The voltage measurement error diagnostic device according to claim 10, wherein the processor diagnoses that the voltage measurement unit has an abnormality when a difference between the measured cell voltage and the calculated cell voltage is equal to or greater than a predetermined threshold value.

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