Method for measuring and diagnosing voltage of battery cell

Abstract

A method for measuring and diagnosing a battery cell voltage is provided. The method for measuring and diagnosing the voltage of a battery cell includes: a process of calculating a voltage across opposite ends of a first path resistor to calculate a voltage across opposite ends of a path resistor connected to an output path of the battery cell to be diagnosed; calculating voltages across opposite ends of the second path resistor according to the resistance value of the output path and the voltage of the battery cell to be diagnosed so as to calculate voltages across opposite ends of the path resistor; a process of comparing a voltage between opposite ends of the first path resistor with a voltage between opposite ends of the second path resistor; and diagnosing a measurement error according to a result of comparison of the voltage between the opposite ends of the first path resistor and the voltage between the opposite ends of the second path resistor.

Description

Technical Field

[0001] This invention relates to a battery cell voltage measurement circuit, and more particularly to a battery cell voltage measurement and diagnostic method for diagnosing the battery cell voltage measurement circuit. Background Technology

[0002] Rechargeable batteries, or rechargeable batteries, are widely used as energy sources for mobile devices such as smartphones. Furthermore, batteries are used as an energy source for environmentally friendly vehicles such as electric vehicles and hybrid electric vehicles, proposed as a solution to air pollution caused by fossil fuel-powered gasoline and diesel vehicles. The types of applications using batteries are becoming increasingly diverse, and it is expected that batteries will be used in even more fields and products in the future than they are now.

[0003] Currently available batteries include nickel-cadmium (NiCd), nickel-metal hydride (NiMH), nickel-zinc (NiZn), and lithium-ion (Li-ion) batteries. Among these, lithium-ion batteries have attracted significant attention due to their advantages of free charge / discharge, very low self-discharge rate, and high energy density, as they exhibit virtually no memory effect compared to nickel-based batteries. Furthermore, because lithium-ion batteries can be manufactured in a smaller size and are lightweight, they are used as power sources for mobile devices, and their applications have expanded to include electric vehicles, thus gaining attention as a next-generation energy storage medium.

[0004] These batteries are typically used in the form of battery packs rather than as individual battery cells. A battery pack includes at least one or more battery modules, and a battery module can consist of multiple battery cells. Battery packs have been developed with high capacity and high voltage specifications, enabling them to be used and driven for longer periods in response to consumer demand. For example, as requirements for electric vehicles, such as driving range and maximum output, are increasing, the number of battery modules and battery cells constituting a battery pack is also increasing. Simultaneously, a battery management system (BMS) is implemented to manage the overall state of the battery cells, battery modules, or battery pack.

[0005] However, in the case of a battery with multiple battery cells, the charge level of each cell becomes uneven during repeated charging and discharging. When the battery continues to discharge in an uneven state, the cell with the lowest charge level becomes over-discharged, making stable battery operation difficult. Conversely, when the battery continues to charge in an uneven state, the cell with the highest charge level becomes overcharged, compromising battery safety. For example, if any one cell is at its lowest charging voltage and all other cells are at their highest charging voltage, the battery may fail to charge and discharge properly, even if all other cells have appropriate charging voltages. Therefore, uneven charge levels can lead to some cells being overcharged or over-discharged, resulting in unstable power supply to the load. Furthermore, overcharging or over-discharging of specific cells can cause not only a reduction in battery pack capacity but also battery pack degradation and a shortened battery life. Therefore, accurate measurement of battery cell voltage is crucial. In other words, accurate measurement of battery cell voltage is necessary to determine the state of each battery cell within a confined space and to control the battery cells based on the determined state. When abnormal battery cell voltage is measured, normal diagnostic functions may not be able to be performed correctly, and the accuracy of SOX (including battery performance indicators such as state of charge (SOC) and state of health (SOH)) estimations may deteriorate.

[0006] Simultaneously, when the battery cell voltage measurement circuit malfunctions, the battery cell voltage can be measured abnormally. Therefore, it is necessary to diagnose whether the battery cell voltage is being measured accurately. Conventionally, the voltages of the lines connected to the battery cell are compared to each other to diagnose the battery cell voltage measurement. That is, the voltages measured on the two lines connected in parallel with the battery cell are compared to each other, and when the difference between the voltages measured on the lines is greater than a certain level, it is determined that there is a problem with the battery cell voltage measurement circuit. However, the problem with the conventional method is that when both lines are malfunctioning, the conventional method cannot diagnose the malfunction in the battery cell voltage measurement circuit.

[0007] The relevant existing technologies are as follows: Korean Patent Registration No. 10-1610908; Korean Unexamined Patent Publication No. 10-2023-0108604. Summary of the Invention

[0008] Technical issues

[0009] This invention provides a method for diagnosing battery cell voltage measurement, wherein a battery cell voltage measurement circuit can be used for diagnosis.

[0010] This invention provides a method for diagnosing the measurement of battery cell voltage. This method diagnoses the battery cell voltage measurement circuit by comparing the measured value and the calculated value of the battery cell voltage.

[0011] Technical solution

[0012] A method for diagnosing battery cell voltage measurement according to an embodiment of the present invention includes: a first voltage calculation process across a path resistor, wherein the first voltage calculation process calculates the voltage across a path resistor connected to an output path of the battery cell to be diagnosed; a second voltage calculation process across a path resistor, wherein the second voltage calculation process calculates the voltage across the path resistor based on the resistance value of the output path and the voltage of the battery cell to be diagnosed; a process for comparing the first voltage across the path resistor and the second voltage across the path resistor; and a process for diagnosing an error in the measurement based on the comparison result of the first voltage across the path resistor and the second voltage across the path resistor.

[0013] The first voltage across the path resistor is calculated based on the difference between the voltage measured when the equalization path of the battery cell to be diagnosed is set and the voltage measured when the equalization path is not set.

[0014] The second voltage across the path resistor is calculated based on the voltage of the battery cell to be diagnosed, the sum of the resistance values ​​of the output path of the battery cell to be diagnosed, and the resistance value of the path resistor.

[0015] The second voltage across the path resistor is calculated by dividing the voltage of the battery cell to be diagnosed by the sum of the resistance values ​​of the output path and multiplying the result of the division by the resistance value of the path resistor.

[0016] When the difference between the first voltage across the path resistor and the second voltage across the path resistor exceeds a predetermined reference value, an error is diagnosed as occurring in the voltage measurement.

[0017] A method for diagnosing battery cell voltage measurement according to another embodiment of the present invention is a method for diagnosing the battery cell voltage measurement of a battery pack including multiple battery cells and a battery management system, and includes: a first voltage calculation process across a path resistor, the first voltage calculation process across the path resistor calculating the voltage across the path resistor connected to the output path of the battery cell to be diagnosed based on the voltage of the output terminal of the output path of the battery cell to be diagnosed; a second voltage calculation process across the path resistor calculating the voltage across the path resistor based on the resistance value of the output path and the voltage of the battery cell to be diagnosed; and a diagnostic process, wherein when the difference between the first voltage across the path resistor and the second voltage across the path resistor exceeds a predetermined reference value, the diagnostic process diagnoses an error in the voltage measurement.

[0018] As shown in Formula 1, the voltage during balancing of the battery cell to be diagnosed is used as a reference. V x (Equalization on) and the voltage when equalization is not performed on the battery cell to be diagnosed. V x (Equalization switch) Calculate the first voltage across the path resistor. V11 .

[0019] [Formula 1]

[0020] V11=V x (Equal opening) -V x (Balance)

[0021] As in Formula 2, based on the voltage V of the battery cell to be diagnosed. BC1 The sum of the resistance values ​​of the output path R m The second voltage V12 across the path resistor is calculated using the resistance value R12 of the path resistor.

[0022] [Formula 2]

[0023] Beneficial effects

[0024] According to one embodiment of the present invention, a battery cell voltage measurement diagnostic method compares the voltage across a first path resistor of the battery cell under diagnosis with the voltage across a second path resistor, and determines that a measurement error has occurred when the comparison result exceeds a reference value. That is, measurement errors can be diagnosed by comparing the measured value (first voltage across the path resistor) and the calculated value (second voltage across the path resistor) of the battery cell voltage. In this case, the first voltage across the path resistor can be calculated by measuring the voltage across the path resistor when equalization is performed on the battery cell under diagnosis and by measuring the voltage across the path resistor when equalization is not performed on the battery cell, and by subtracting the measured voltages. Furthermore, the second voltage across the path resistor can be calculated using the voltage of the battery cell under diagnosis and the resistance values ​​of multiple resistors disposed in the output path.

[0025] As described above, in this invention, by comparing the first voltage and the second voltage across the path resistor and determining the measurement error based on the comparison result, measurement errors can be diagnosed even when both lines connected to one terminal of the battery cell are abnormal or one of the two lines is abnormal. In other words, according to this invention, the problem that conventional methods cannot diagnose abnormalities in the battery cell voltage measurement circuit when both lines connected to one terminal of the battery cell are abnormal can be solved. Attached Figure Description

[0026] Figure 1 This is a circuit diagram of a circuit for diagnosing the measurement of battery cell voltage according to an embodiment of the present invention.

[0027] Figure 2 This is a flowchart of a method for measuring the voltage of a battery cell according to an embodiment of the present invention.

[0028] Figure 3 This is a circuit diagram illustrating the operation of a method for measuring the voltage of a battery cell according to the present invention.

[0029] Figure 4 This is a block diagram of a device for diagnosing the measurement of battery cell voltage according to an embodiment of the present invention. Detailed Implementation

[0030] In the following, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below, but will be implemented in various different forms, and these embodiments are provided only to make the disclosure complete and to fully inform those skilled in the art of the scope of the invention.

[0031] Figure 1This is a circuit diagram of a method for measuring the voltage of a battery cell according to an embodiment of the present invention.

[0032] Reference Figure 1 According to an embodiment of the present invention, a circuit for diagnosing the voltage measurement of battery cells may include multiple battery cells BC1, BC2, BC3..., multiple first lines L11, L12, L13 and L14 respectively connected to the positive (+) and negative (-) terminals of the multiple battery cells BC1, BC2, BC3, and L24, multiple second lines L21, L22, L23 and L24, multiple first resistors R11, R12, R13 and R14 respectively disposed on the multiple first lines L11, L12, L13 and L14, multiple filters F11, F12, F13 and F14, multiple second resistors R21 and R22 selectively disposed on the multiple second lines L21, L22, L23 and L24, and multiple switches SW11, SW12, SW13 and SW14 connecting adjacent second lines L21, L22, L23 and L24 to each other. In addition, multiple first measurement pins CT1, CT2, CT3 and CT4 can be respectively set at the corresponding ends of multiple first lines L11, L12, L13 and L14, and multiple second pins CB1, CB2, CB3 and CB4 can be respectively set at the corresponding ends of multiple second lines L21, L22, L23 and L24.

[0033] The positive (+) and negative (-) terminals of multiple battery cells BC1, BC2, and BC3 are connected to the first lines L11, L12, L13, and L14 and the second lines L21, L22, L23, and L24. In this case, the first lines L11, L12, L13, and L14 are connected in parallel with the second lines L21, L22, L23, and L24. That is, the positive (+) terminal of the first battery cell BC1 is connected to the parallel-connected lines 1-1 L11 and 2-1 L21, and the negative (-) terminal of the first battery cell BC1 is connected to the parallel-connected lines 1-2 L12 and 2-2 L22. Furthermore, the positive (+) terminal of the second battery cell BC2 is connected to the parallel-connected lines 1-2 L12 and 2-2 L22. The negative terminal (-) of the second battery cell BC2 is connected to lines 1-3 (L13) and 2-3 (L23) which are connected in parallel. Furthermore, the positive terminal (+) of the third battery cell BC3 is connected to lines 1-3 (L13) and 2-3 (L23) which are connected in parallel, and the negative terminal (-) of the third battery cell BC3 is connected to lines 1-4 (L14) and 2-4 (L24) which are connected in parallel. In other words, the first and second lines connected to the negative terminal (-) of one battery cell are connected to the positive terminal (+) of the adjacent battery cell. In other words, the negative and positive terminals of two adjacent battery cells share the first and second lines.

[0034] First resistors R11, R12, R13, and R14, and filters F11, F12, F13, and F14, are connected in series to the first lines L11, L12, L13, and L14, respectively. Second resistors R21 and R22 are selectively connected to the second lines L21, L22, L23, and L24. A second-first resistor R21 is connected to the second-first line L21, and a second-second resistor R22 is connected to the second-third line L23. Second resistors R21 and R22 are alternately connected to multiple second lines L21, L22, L23, and L24. In other words, second resistors R21 and R22 are connected to the odd-numbered second lines L21 and L23, but not to the even-numbered second lines L22 and L24. Of course, the second resistors R21 and R22 can be connected to the even-numbered second lines L22 and L24 among the multiple second lines L21, L22, L23, and L24, and can be excluded from connection to the odd-numbered second lines L21 and L23. Simultaneously, the second lines L21, L22, L23, and L24 can branch from the first lines L11, L12, L13, and L14, respectively. For example, the second lines L21, L22, L23, and L24 can branch from nodes N11, N12, N13, and N14 between the first resistors R11, R12, R13, and R14 and the filters F11, F12, F13, and F14, respectively. Furthermore, the first measurement pins CT1, CT2, CT3, and CT4 can be respectively set on the first lines L11, L12, L13, and L14, and the second measurement pins CB1, CB2, CB3, and CB4 can be respectively set on the second lines L21, L22, L23, and L24. That is, the first-1 measurement pin CT1 and the second-1 measurement pin CB1 are respectively set on the first-1 line L11 and the second-1 line L21, which are connected in parallel; the first-2 measurement pin CT2 and the second-2 measurement pin CB2 are respectively set on the first-2 line L12 and the second-2 line L22, which are connected in parallel; and the first-3 measurement pin CT3 and the second-3 measurement pin CB3 are respectively set on the first-3 line L13 and the second-3 line L23, which are connected in parallel.

[0035] Furthermore, the second lines L21, L22, L23, and L24 can be connected via switches SW11, SW12, SW13, and SW14. That is, the first switch SW11 can be positioned between line 2-1 L21 and line 2-2 L22, the second switch SW12 can be positioned between line 2-2 L22 and line 2-3 L23, and the third switch SW13 can be positioned between line 2-3 L23 and line 2-4 L24. Switches SW11, SW12, and SW13 can be turned on or off according to a control signal with a predetermined level to connect or disconnect the second lines L21, L22, L23, and L24 from each other. In other words, when the first switch SW11 is turned on, line 2-1 L21 and line 2-2 L22 can be connected to each other; when the second switch SW12 is turned on, line 2-2 L22 and line 2-3 L23 can be connected to each other; and when the third switch SW13 is turned on, line 2-3 L23 and line 2-4 L24 can be connected to each other.

[0036] Figure 2 This is a flowchart of a method for measuring the voltage of a battery cell according to an embodiment of the present invention. Furthermore, Figure 3 This is a circuit diagram illustrating the process of calculating the voltage across a first path resistor according to a method for measuring the voltage of a battery cell, based on an embodiment of the present invention.

[0037] Reference Figure 2 A method for diagnosing battery cell voltage measurement according to an embodiment of the present invention may include: a first voltage calculation process across a path resistor, wherein the first voltage calculation process across the path resistor calculates the voltage across the path resistor connected to the output path of the battery cell to be diagnosed based on the voltage at the output terminal of the output path of the battery cell to be diagnosed (S110); a second voltage calculation process across the path resistor, wherein the second voltage calculation process across the path resistor calculates the voltage across the path resistor based on the resistance value of the output path and the voltage of the battery cell to be diagnosed (S120); a process for comparing the first voltage and the second voltage across the path resistor (S130); and a diagnostic process in which, as a result of comparing the first voltage and the second voltage across the path resistor, the difference between the first voltage and the second voltage across the path resistor exceeds a predetermined reference value, the diagnostic process diagnoses an error in the voltage measurement (S150); and a process in which, when the difference is within the predetermined reference value, it is diagnosed as a normal measurement (S140). The method for diagnosing battery cell voltage measurement according to an embodiment of the present invention is described below for each process.

[0038] S110: Perform balancing of the battery cell to be diagnosed to calculate the first voltage across the path resistor. For example, when the first battery cell BC1 is selected as the battery cell to be diagnosed, the first switch SW11 is turned on and the remaining switches SW12, SW13, and SW14 are turned off to balance the first battery cell BC1. In this case, the current I... N Along Figure 3 The path shown indicates the flow. That is, when the first switch SW11 is turned on to balance the first battery cell BC1, the current I... N The current flows from the positive terminal of the first battery cell BC1 through resistors R11 (1-1), R21 (2-1), and R12 (1-2) to the negative terminal of the first battery cell BC1. In this case, a voltage drop occurs due to resistor R12 (1-2), and the voltage V11 is measured. Therefore, the voltage V11 before and after equalization can be calculated as shown in Equation 1 using the voltage difference before and after current flow. Where V... x The voltage value of the first node N11 of line 2-2 L22 branching from line 1-2 L12 is given. The voltage value of the first node N11 can be measured at the measurement pin CT2 of line 1-2.

[0039] [Formula 1]

[0040] V11=V x (Equal opening) -V x (Balance)

[0041] In other words, the first voltage V11 across the path resistor can be calculated by subtracting the voltage applied to the node when balancing the battery cell not being diagnosed from the voltage applied to the node when balancing the battery cell not being diagnosed.

[0042] S120: The second voltage across the path resistor can be calculated because the first and second resistors used in the diagnostic circuit, the battery cell voltage, etc., are known. That is, because the current I flowing in the output path of the battery cell to be diagnosed... N Since the resistance value of resistor R12 in the output path is known, it can be calculated based on the current I as shown in Formula 2. N The second voltage across the path resistor is calculated using the resistance value of resistor R12.

[0043] [Formula 2]

[0044] In addition, current I N As in Formula 3, the voltage V of the battery cell to be diagnosed (i.e., the first battery cell BC1) can be used. BC1And the sum of the resistance values ​​of resistors R11 (1st), R21 (2nd), and R12 (1st) on the output path. In [Formula 3], R... m It is the sum of the resistance values ​​of the output path.

[0045] [Formula 3]

[0046] Therefore, the second voltage V12 across the path resistor can be calculated according to Formulas 2 and 3 as shown in Formula 4. In other words, the second voltage V12 across the path resistor can be calculated by changing the voltage V of the first battery cell BC1. BC1 Divide by the resistance value R of the output path m The sum is calculated by multiplying the result of the division by the resistance value of resistor R12, which causes the voltage drop.

[0047] [Formula 4]

[0048] S130, S140, and S150: The first voltage V11 across the path resistor is compared with the second voltage V12 across the path resistor (S130). That is, the measured and calculated values ​​of the voltages across the path resistor are compared with each other. As a result of the comparison, if the difference between the first voltage V11 and the second voltage V12 across the path resistor is greater than a predetermined reference value, an error in the voltage measurement is diagnosed (S150), and if the difference is less than the reference value, a normal measurement is diagnosed (S140).

[0049] Figure 4 This is a block diagram illustrating the configuration of a device for diagnosing battery cell voltage measurements according to an embodiment of the present invention. That is, Figure 1 The circuitry used for measuring battery cell voltage can be connected to diagnostic equipment to form, for example... Figure 4 The diagnostic equipment shown.

[0050] Reference Figure 4According to an embodiment of the present invention, an apparatus for diagnosing the measurement of battery cell voltage may include: a battery module 100, which includes a plurality of battery cells BC1, BC2 and BC3; and a diagnostic unit 200, which diagnoses errors in voltage measurement in the battery cell to be diagnosed. Here, the diagnostic unit 200 may be disposed within the BMS. In addition, the diagnostic unit 200 may include: a measurement unit 210, which is connected to a plurality of first measurement pins CT1, CT2, CT3 and CT4 and a plurality of second measurement pins CB1, CB2, CB3 and CB4 of the diagnostic circuit to measure voltage; a storage unit 220, which stores information such as the voltage of battery cells BC1, BC2 and BC3 constituting the diagnostic circuit, the resistance values ​​of a plurality of resistors, current, etc.; a comparison unit 230, which compares a first voltage across a path resistor with a second voltage across a path resistor; and a determination control unit 240, which generates control signals for controlling switches SW11, SW12, SW13 and SW14, and determines the diagnostic result for measurement based on the comparison result of the comparison unit 230.

[0051] Measurement unit 210 is connected to a plurality of first measurement pins CT1, CT2, CT3, and CT4 and a plurality of second measurement pins CB1, CB2, CB3, and CB4. Measurement unit 210 measures voltage via the plurality of first measurement pins CT1, CT2, CT3, and CT4 and the plurality of second measurement pins CB1, CB2, CB3, and CB4. That is, measurement unit 210 can measure the voltage of the battery cell to be diagnosed via the first measurement pins CT1, CT2, CT3, and CT4 and the second measurement pins CB1, CB2, CB3, and CB4 connected to the battery cell to be diagnosed. Furthermore, according to the invention, measurement unit 210 can measure the voltage when cell balancing of a specific battery cell is performed and the voltage when cell balancing of the corresponding battery cell is not performed. That is, measurement unit 210 measures the voltage when balancing of the battery cell to be diagnosed is performed and the voltage when balancing of the battery cell to be diagnosed is not performed, and accordingly calculates the first voltage V11 across the path resistor.

[0052] Storage unit 220 can store the characteristics or specifications of battery cells BC1, BC2, and BC3, as well as each component constituting the diagnostic circuit. Specifically, storage unit 220 stores data such as the charging or discharging voltages of battery cells BC1, BC2, and BC3; the current voltage state of battery cells BC1, BC2, and BC3; the resistance values ​​of the plurality of first resistors R11, R12, R13, and R14 constituting the diagnostic circuit; the resistance values ​​of the plurality of second resistors R21 and R22; and the current values ​​of each battery cell BC1, BC2, and BC3 determined based on the resistance values ​​of the first and second resistors and the voltage values ​​of battery cells BC1, BC2, and BC3. Furthermore, storage unit 220 can store measurement values ​​measured by measurement unit 210, such as the voltage when cell balancing of a specific battery cell is performed and the voltage when cell balancing of the corresponding battery cell is not performed.

[0053] Comparison unit 230 compares a first voltage and a second voltage across the path resistor of the battery cell to be diagnosed. That is, comparison unit 230 compares the measured and calculated values ​​of the voltage across the path resistor. To do this, firstly, comparison unit 230 uses the voltage from measurement unit 210 during battery cell balancing of the battery cell to be diagnosed and the voltage when battery cell balancing is not performed to calculate the voltage difference. That is, comparison unit 230 calculates the first voltage across the path resistor of the battery cell to be diagnosed. Next, comparison unit 230 uses the voltage of the battery cell to be diagnosed from storage unit 220 and the sum of the resistance values ​​of multiple resistors disposed in the output path to calculate the second voltage across the path resistor. That is, comparison unit 230 calculates the second voltage across the path resistor according to formulas 2 to 4. Comparison unit 230 compares the first voltage across the path resistor with the second voltage across the path resistor.

[0054] The determination control unit 240 diagnoses the measurement results based on the comparison result of the comparison unit 230. Specifically, when the difference between the first voltage across the path resistor and the second voltage across the path resistor compared by the comparison unit 230 is greater than a set reference value, the determination control unit 240 diagnoses a measurement error; when the difference is less than the set reference value, it diagnoses a normal measurement. In this case, when a measurement error is diagnosed, at least one of the multiple first measurement pins CT1, CT2, CT3, CT4 and the multiple second measurement pins CB1, CB2, CB3, CB4 can be identified as abnormal, or a circuit malfunction can be identified. Simultaneously, the determination control unit 240 can generate control signals for controlling switches SW11, SW12, SW13, and SW14. In other words, the determination control unit 240 can select the battery cell to be diagnosed and control the switches connected to the corresponding battery cell's measurement pins, thereby performing battery cell equalization.

[0055] As described above, in the method for diagnosing battery cell voltage measurement according to an embodiment of the present invention, a first voltage across a path resistor and a second voltage across the path resistor are compared, and if the comparison result is greater than a reference value, it can be diagnosed as a measurement error. In this case, the first voltage across the path resistor can be calculated by subtracting the voltage applied across the path resistor when balancing is performed from the voltage applied across the path resistor when balancing is not performed on the battery cell to be diagnosed. Furthermore, the second voltage across the path resistor can be calculated using the voltage of the battery cell to be diagnosed and the resistance values ​​of a plurality of resistors disposed in the output path.

[0056] The problem with traditional methods is that they cannot diagnose abnormalities in the battery cell voltage measurement circuit when both lines connected to one terminal of the battery cell are faulty. However, in this invention, a first voltage and a second voltage across the path resistor are compared, and the measurement error is diagnosed based on the comparison result. Therefore, even when both lines connected to one terminal of the battery cell are faulty, or when one of the two lines is faulty, the measurement error can still be diagnosed.

[0057] The technical concept of the present invention described above has been described in detail according to the above embodiments. However, it should be noted that the above embodiments are for description purposes only and not for limitation. Furthermore, those skilled in the art will understand that various embodiments are possible within the scope of the technical concept of the present invention.

[0058] The names of the reference numerals used in the specification and drawings of this invention are as follows.

[0059] BC1, BC2, BC3: Battery cells; L11, L12, L13, L14: First circuit

[0060] L21, L22, L23, L24: Second circuit; R11, R12, R13, R14: First resistor

[0061] R21, R22: Second resistors; SW11, SW12, SW13, SW14: Switches

[0062] 100: Battery module 200: BMS

[0063] 210: Measurement unit; 220: Storage unit

[0064] 230: Comparison unit; 240: Determining control unit

Claims

1. A method for measuring and diagnosing the voltage of a battery cell, the method comprising: The first voltage calculation process across the path resistor calculates the voltage across the path resistor connected to the output path of the battery cell to be diagnosed. The second voltage calculation process across the path resistor is based on the resistance value of the output path and the voltage of the battery cell to be diagnosed to calculate the voltage across the path resistor. The process of comparing the first voltage across the path resistor and the second voltage across the path resistor; as well as The process of diagnosing errors in measurement based on the comparison between the first voltage across the path resistor and the second voltage across the path resistor.

2. The method according to claim 1, wherein, The first voltage across the path resistor is calculated based on the difference between the voltage measured when the equalization path of the battery cell to be diagnosed is set and the voltage measured when the equalization path is not set.

3. The method according to claim 2, wherein, The second voltage across the path resistor is calculated based on the voltage of the battery cell to be diagnosed, the sum of the resistance values ​​of the output path of the battery cell to be diagnosed, and the resistance value of the path resistor.

4. The method according to claim 3, wherein, The second voltage across the path resistor is calculated by dividing the voltage of the battery cell to be diagnosed by the sum of the resistance values ​​of the output path and multiplying the result of the division by the resistance value of the path resistor.

5. The method according to claim 4, wherein, When the difference between the first voltage across the path resistor and the second voltage across the path resistor exceeds a predetermined reference value, an error is diagnosed as occurring in the voltage measurement.

6. A method for measuring the cell voltage of a battery pack comprising multiple battery cells and a battery management system, the method comprising: The first voltage calculation process across the path resistor is based on the voltage at the output terminal of the output path of the battery cell to be diagnosed, which is used to calculate the voltage across the path resistor connected to the output path of the battery cell to be diagnosed. The second voltage calculation process across the path resistor is based on the resistance value of the output path and the voltage of the battery cell to be diagnosed to calculate the voltage across the path resistor. as well as During the diagnostic process, if the difference between the first voltage across the path resistor and the second voltage across the path resistor exceeds a predetermined reference value, the diagnostic process diagnoses an error in the voltage measurement.

7. The method according to claim 6, wherein, As shown in Formula 1, the voltage during balancing of the battery cell to be diagnosed is used as a reference. V x (Equalization on) and voltage when equalization is not performed on the battery cell to be diagnosed. V x (Equalization switch) Calculate the first voltage across the path resistor. V11 , [Formula 1] V11=V x (Equal opening) -V x (Balance) 。 8. The method according to claim 7, wherein, As formula 2, according to the voltage V of the battery cell to be diagnosed BC1 The sum of the resistance values R of the output paths m And the resistance value R12 of the path resistor, the second voltage V12 across the path resistor is calculated, [Formula 2] 。

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