Method for measuring and diagnosing battery cell voltage

Abstract

The present invention proposes a method for measuring and diagnosing a battery cell voltage. The method for measuring and diagnosing a battery cell voltage comprises: a process of calculating a voltage between opposite ends of a first path resistor in order to calculate a voltage between opposite ends of a path resistor connected to an output path of a battery cell to be diagnosed; a process of calculating a voltage between opposite ends of a second path resistor in order to calculate a voltage between opposite ends of a path resistor from a resistance value of the output path and a voltage of the battery cell to be diagnosed; a process of comparing the voltage between the opposite ends of the first path resistor with the voltage between the opposite ends of the second path resistor; and a process of diagnosing a measurement error according to a result of the 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

Battery cell voltage measurement diagnostic method

[0001] The present invention relates to a battery cell voltage measurement circuit, and more particularly, to a battery voltage measurement diagnosis method for diagnosing a battery cell voltage measurement circuit.

[0002] Rechargeable secondary cells, or batteries, are widely used as energy sources for mobile devices such as smartphones. Furthermore, batteries are also being used as energy sources for eco-friendly vehicles, such as electric and hybrid electric vehicles, which are being proposed as a solution to air pollution caused by fossil fuel-powered gasoline and diesel vehicles. The types of applications utilizing batteries are becoming increasingly diverse, and batteries are expected to be applied to a wider range of fields and products in the future.

[0003] Currently commercially available batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium-ion batteries. Among these, lithium-ion batteries are gaining attention for their advantages: virtually no memory effect compared to nickel-based batteries, allowing for easy charging and discharging, a very low self-discharge rate, and high energy density. Furthermore, lithium-ion batteries can be manufactured in small, lightweight designs, making them ideal power sources for mobile devices. Their expanding applications, including powering electric vehicles, are attracting attention as a next-generation energy storage medium.

[0004] These batteries are typically used in the form of battery packs rather than as single battery cells. A battery pack includes at least one battery module, which may be comprised of multiple battery cells. Battery packs are being developed with high-capacity and high-voltage specifications to meet consumer demands for longer life and more powerful operation. For example, as requirements for electric vehicles, such as driving range and maximum output, increase, the number of battery modules and cells that make up a battery pack is increasing. Meanwhile, a battery management system (BMS) is installed to manage the overall condition of the battery cells, battery modules, or battery pack.

[0005] However, in the case of a battery with multiple connected cells, repeated charging and discharging can lead to an imbalance in the charge levels of each cell. If the battery continues to discharge while in this imbalanced state, certain cells with lower charge levels will be over-discharged, compromising stable battery operation. Conversely, if the battery continues to charge while in this imbalanced state, certain cells with higher charge levels will be overcharged, jeopardizing battery safety. For example, if one battery cell has the lowest charge voltage and another has the highest charge voltage, the battery may not only charge but also fail to discharge, even if all other cells have adequate charge voltages. This imbalance in charge levels can cause some battery cells to become overcharged or over-discharged, resulting in an inability to supply power reliably to the load. Furthermore, overcharging or over-discharging of specific battery cells can not only reduce the capacity of the battery pack, but also deteriorate it and shorten its lifespan. Therefore, accurately measuring battery cell voltage is crucial. This is essential for assessing the condition of each battery cell within a confined space and controlling it accordingly. Abnormally measured battery cell voltages can prevent normal diagnostic functions or cause problems with battery performance indicators such as SOC (State of Charge) and SOH (State of Health).

[0006] Meanwhile, if the measurement circuit is abnormal, the battery cell voltage may be measured abnormally. Therefore, it is necessary to diagnose whether the battery cell voltage is measured accurately. In the past, to diagnose battery cell voltage measurement, the voltages of the lines connected to the battery cell were compared. That is, the voltages measured on two lines connected in parallel to the battery cell were compared, and if the voltage difference measured on each line exceeded a certain size, a problem was determined in the battery cell voltage measurement circuit. However, the conventional method had a problem in that it could not diagnose anomalies in the battery cell voltage measurement circuit if both lines were abnormal.

[0007] Related prior art is as follows.

[0008] Korean Patent No. 10-1610908

[0009] Korean Patent Publication No. 10-2023-0108604

[0010] The present invention provides a battery cell voltage measurement diagnostic method capable of diagnosing a battery cell voltage measurement circuit.

[0011] The present invention provides a battery cell voltage measurement diagnosis method for diagnosing a battery cell voltage measurement circuit by comparing a measured value and a calculated value of a battery cell voltage.

[0012] A battery cell voltage measurement diagnosis method according to one embodiment of the present invention includes a first path resistance both-end voltage calculation process for calculating a voltage across a path resistor connected to an output path of a battery cell to be diagnosed; a second path resistance both-end voltage calculation process for calculating a voltage across the path resistor from a resistance value of the output path and a voltage of the battery cell to be diagnosed; a process for comparing the first path resistance both-end voltage and the second path resistance both-end voltage; and a process for diagnosing a measurement error based on a comparison result of the first and second path resistance both-end voltages.

[0013] The voltage across the first path resistance is calculated from the difference between the voltage measured when the balancing path of the battery cell to be diagnosed is set and the voltage measured when the balancing path is not set.

[0014] The above second path resistance voltage is calculated from 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 resistance.

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

[0016] If the voltage across the first and second path resistors differs by exceeding a predetermined reference value, it is diagnosed as an error in voltage measurement.

[0017] According to other embodiments of the present invention, a battery cell voltage measurement diagnosis method of a battery pack including a plurality of battery cells and a BMS includes a first path resistance across-end voltage calculation process for calculating a voltage across a path resistor connected to an output path of a battery cell to be diagnosed from a voltage at an output terminal of the output path; a second path resistance across-end voltage calculation process for calculating a voltage across the path resistor from a resistance value of the output path and a voltage of the battery cell to be diagnosed; and a process for diagnosing an error in voltage measurement when a difference between the first and second path resistance across-end voltages exceeds a predetermined reference value.

[0018] The voltage across the first path resistor (V11) is calculated from the voltage (Vx(balancing ON)) when balancing the battery cell to be diagnosed is performed and the voltage (Vx(balancing OFF)) when balancing is not performed, as in [Mathematical Formula 1].

[0019] [Mathematical Formula 1]

[0020]

[0021] The above second path resistance voltage (V12) is calculated from the voltage of the battery cell to be diagnosed (VBC1), the sum of the resistance values ​​of the output path (Rm), and the resistance value of the path resistance (R12), as in [Mathematical Formula 2].

[0022] [Equation 2]

[0023]

[0024] According to an embodiment of the present invention, a battery cell voltage measurement diagnosis method can compare a voltage across a first path resistor and a voltage across a second path resistor of a battery cell to be diagnosed, and if the comparison result is greater than a reference value, a diagnosis error can be determined. That is, an error can be diagnosed by comparing a measured value (voltage across the first path resistor) and a calculated value (voltage across the second path resistor) of the battery cell voltage. At this time, the voltage across the first path resistor can be calculated by measuring the voltage across the path resistor when balancing the battery cell to be diagnosed and subtracting the voltage across the path resistor when balancing is not performed. In addition, the voltage across the second path resistor can be calculated using the voltage of the battery cell to be diagnosed and the resistance values ​​of multiple resistors provided in the output path.

[0025] As described above, the present invention can diagnose an error even when both lines connected to one terminal of a battery cell are abnormal or one is in an emergency state by comparing the voltages across the first and second path resistors and determining an error based on the comparison result. In other words, the present invention can solve the problem of the conventional method of not being able to diagnose an abnormality in the battery cell voltage measurement circuit when both lines connected to one terminal of a battery cell are abnormal.

[0026] FIG. 1 is a circuit diagram for battery cell voltage measurement and diagnosis according to one embodiment of the present invention.

[0027] FIG. 2 is a flowchart of a battery cell voltage measurement diagnostic method according to an embodiment of the present invention.

[0028] Figure 3 is a circuit diagram for explaining the operation according to the battery cell voltage measurement diagnosis method of the present invention.

[0029] FIG. 4 is a block diagram of a battery cell voltage measurement diagnostic device according to an embodiment of the present invention.

[0030] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms. These embodiments are provided solely to ensure complete disclosure of the present invention and to fully inform those of ordinary skill in the art of the scope of the invention.

[0031] FIG. 1 is a circuit diagram for a battery cell voltage measurement diagnostic method according to one embodiment of the present invention.

[0032] Referring to FIG. 1, a circuit for battery cell voltage measurement diagnosis according to an embodiment of the present invention comprises a plurality of battery cells (BC1, BC2, BC3, …), a plurality of first lines (L11, L12, L13, L14) and second lines (L21, L22, L23, L24) connected to the positive terminals (+) and negative terminals (-) of each of the plurality of battery cells (BC1, BC2, BC3), a plurality of first resistors (R11, R12, R13, R14) and a plurality of filters (F11, F12, F13, F14) respectively provided in the plurality of first lines (L11, L12, L13, L14), a plurality of second resistors (R21, R22) selectively provided in the plurality of second lines (L21, L22, L23, L24), and a plurality of adjacent second lines (L21, L22, It may include a plurality of switches (SW11, SW12, SW13, SW14) that connect the plurality of first lines (L11, L12, L13, L14) to each other. In addition, a plurality of first measurement pins (CT1, CT2, CT3, CT4) may be provided at the ends of the plurality of first lines (L11, L12, L13, L14), and a plurality of second pins (CB1, CB2, CB3, CB4) may be provided at the ends of the plurality of second lines (L21, L22, L23, L24).

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

[0034] First resistors (R11, R12, R13, R14) and filters (F11, F12, F13, F14) are connected in series to the first lines (L11, L12, L13, L14), and second resistors (R21, R22) are selectively connected to the second lines (L21, L22, L23, L24). The 2-1 resistor (R21) is connected to the 2-1 line (L21), and the 2-2 resistor (R22) is connected to the 2-3 line (L23). The second resistors (R21, R22) are alternately connected to a plurality of second lines (L21, L22, L23, L24). In other words, the second resistors (R21, R22) are connected to odd-numbered second lines (L21, L23) among the plurality of second lines (L21, L22, L23, L24) and are not connected to even-numbered second lines (L22, L24). Of course, the second resistors (R21, R22) may be connected to even-numbered second lines (L22, L24) among the plurality of second lines (L21, L22, L23, L24) and are not connected to odd-numbered second lines (L21, L23). Meanwhile, the second lines (L21, L22, L23, L24) may be branched from the first lines (L11, L12, L13, L14), respectively. For example, the second line (L21, L22, L23, L24) may be branched from the node (N11, N12, N13, N14) between the first resistor (R11, R12, R13, R14) and the filter (F11, F12, F13, F14). In addition, the first line (L11, L12, L13, L14) may be provided with the first measurement pin (CT1, CT2, CT3, CT4), and the second line (L21, L22, L23, L24) may be provided with the second measurement pin (CB1, CB2, CB3, CB4).That is, the 1-1 line (L11) and the 2-1 line (L21) connected in parallel with each other are provided with the 1-1 measuring pin (CT1) and the 2-1 measuring pin (CB1), respectively, the 1-2 line (L12) and the 2-2 line (L22) connected in parallel with each other are provided with the 1-2 measuring pin (CT2) and the 2-2 measuring pin (CB2), respectively, and the 1-3 line (L13) and the 2-3 line (L23) connected in parallel with each other are provided with the 1-3 measuring pin (CT3) and the 2-3 measuring pin (CB3), respectively.

[0035] In addition, the second lines (L21, L22, L23, L24) can be connected by switches (SW11, SW12, SW13, SW14). That is, a first switch (SW11) can be provided between the 2-1 line (L21) and the 2-2 line (L22), a second switch (SW12) can be provided between the 2-2 line (L22) and the 2-3 line (L23), and a third switch (SW13) can be provided between the 2-3 line (L23) and the 2-4 line (L24). The switches (SW11, SW12, SW13) can be turned on or off according to a control signal of a predetermined level to connect or disconnect the second lines (L21, L22, L23, L24) with each other. That is, when the first switch (SW11) is turned on, the 2-1 line (L21) and the 2-2 line (L22) are connected, when the second switch (SW12) is turned on, the 2-2 line (L22) and the 2-3 line (L23) are connected, and when the third switch (SW13) is turned on, the 2-3 line (L23) and the 2-4 line (L24) can be connected.

[0036]

[0037] FIG. 2 is a flowchart illustrating a battery cell voltage measurement and diagnosis method according to an embodiment of the present invention. In addition, FIG. 3 is a circuit diagram illustrating a process for calculating a voltage across a first path resistor according to a battery cell voltage measurement and diagnosis method according to an embodiment of the present invention.

[0038] Referring to FIG. 2, a battery cell voltage measurement diagnosis method according to an embodiment of the present invention may include a first path resistance both-end voltage calculation process (S110) for calculating the voltage across the path resistor connected to the output path of the battery cell to be diagnosed from the voltage at the output terminal of the output path, a second path resistance both-end voltage calculation process (S120) for calculating the voltage across the path resistor from the resistance value of the output path and the voltage of the battery cell to be diagnosed, a process (S130) for comparing the voltage across the first path resistor and the voltage across the second path resistor, and a process (S150) for diagnosing a voltage measurement error if the difference between the first and second path resistor both-end voltages exceeds a predetermined reference value and diagnosing it as normal if it is within the reference value. The battery cell voltage measurement diagnosis method according to an embodiment of the present invention will be described in detail by process as follows.

[0039] S110: Balancing of the battery cell to be diagnosed is performed to calculate the voltage across the first path resistance. 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, SW14) are turned off to balance the first battery cell (BC1). In this case, the current (IN) flows along the path as shown in FIG. 3. That is, when the first switch (SW11) is turned on to balance the first battery cell (BC1), the current (IN) flows from the positive terminal of the first battery cell (BC1) through the 1-1 resistor (R11), the 2-1 resistor (R21), and the 1-2 resistor (R12) to the negative terminal of the first battery cell (BC1). At this time, a voltage drop occurs due to the 1-2 resistor (R12) and the voltage (V11) is measured. Therefore, the voltage (V11) before and after balancing can be calculated through the voltage difference before and after the current flows, as in [Mathematical Formula 1]. Here, Vx is the voltage value of the first node (N11) where the 2-2 line (L22) branches off from the 1-2 line (L12), and this voltage value of the first node (N11) can be measured at the 1-2 measurement pin (CT2).

[0040]

[0041] That is, the voltage across the first path resistor (V11) can be calculated by subtracting the voltage applied to the node when balancing is not performed from the voltage applied to the node when balancing the battery cell to be diagnosed is performed.

[0042] S120: The voltage across the second path resistor can be calculated since the first and second resistors applied to the diagnostic circuit, the battery cell voltage, etc. are known. That is, the voltage across the second path resistor (V12) can be calculated from the current (IN) flowing in the output path of the battery cell to be diagnosed and the resistance value of the resistor (R12) of the output path as in [Mathematical Formula 2] since the resistance value of the resistor (R12) of the output path and the current (IN) flowing in the output path of the battery cell to be diagnosed are known.

[0043]

[0044] In addition, the current (IN) can be calculated from the voltage (VBC1) of the battery cell to be diagnosed, i.e., the voltage of the first battery cell (BC1), and the sum of the resistance values ​​of the output path, i.e., the first-first resistor (R11), the second-first resistor (R21), and the first-second resistor (R12), as in [Mathematical Expression 3]. In [Mathematical Expression 3], Rm is the sum of the resistance values ​​of the output path.

[0045]

[0046] Therefore, the voltage across the second path resistor (V12) can be calculated from [Mathematical Formula 2] and [Mathematical Formula 3] as in [Mathematical Formula 4]. That is, the voltage across the second path resistor (V12) can be calculated by dividing the voltage of the voltage (VBC1) of the first battery cell (BC1) by the sum of the resistance values ​​of the output path (Rm) and multiplying by the resistance value of the resistor (R12) where the voltage drop occurs.

[0047]

[0048] S130, S140 and S150: Compare the voltage across the first path resistor (V11) with the voltage across the second path resistor (V12) (S130). That is, compare the measured and calculated voltages across the path resistors. If the difference between the voltage across the first path resistor (V11) and the voltage across the second path resistor (V12) is greater than a predetermined reference value as a result of the comparison, it is diagnosed as an error (S150), and if it is less than the reference value, it is diagnosed as normal (S140).

[0049] Fig. 4 is a block diagram illustrating the configuration of a device for battery cell voltage measurement and diagnosis according to an embodiment of the present invention. That is, the circuit for battery cell voltage measurement and diagnosis of Fig. 1 can be connected to a diagnostic device to configure a diagnostic device such as that of Fig. 4.

[0050] Referring to FIG. 4, a battery cell voltage measurement diagnostic device according to an embodiment of the present invention may include a battery module (100) including a plurality of battery cells (BC1, BC2, BC3), and a diagnostic unit (200) that diagnoses a voltage measurement error of a battery cell to be diagnosed. Here, the diagnostic unit (200) may be provided within a BMS. In addition, the diagnostic unit (200) may include a measuring unit (210) that is connected to a plurality of first measuring pins (CT1, CT2, CT3, CT4) and a plurality of second measuring pins (CB1, CB2, CB3, CB4) of the diagnostic circuit to measure voltage, a storage unit (220) that stores information such as voltage of battery cells (BC1, BC2, BC3) constituting the diagnostic circuit and resistance values ​​of multiple resistors, current, etc., a comparison unit (230) that compares a voltage across a first path resistor and a voltage across a second path resistor, and a judgment control unit (240) that generates a control signal that controls switches (SW11, SW12, SW13, SW14) and judges a measurement diagnosis result according to a comparison result of the comparison unit (230).

[0051] The measuring unit (210) is connected to a plurality of first measuring pins (CT1, CT2, CT3, CT4) and a plurality of second measuring pins (CB1, CB2, CB3, CB4). The measuring unit (210) measures voltages through the plurality of first measuring pins (CT1, CT2, CT3, CT4) and the plurality of second measuring pins (CB1, CB2, CB3, CB4). That is, the measuring unit (210) can measure the voltage of a battery cell to be diagnosed through the first measuring pins (CT1, CT2, CT3, CT4) and the second measuring pins (CB1, CB2, CB3, CB4) connected thereto. In addition, the measuring unit (210) according to the present invention can measure the voltage when performing cell balancing on a specific battery cell and the voltage when performing cell balancing on the corresponding battery cell. That is, the measuring unit (210) measures the voltage when balancing the battery cell to be diagnosed is performed and the voltage when balancing is not performed, and accordingly calculates the voltage across the first path resistor (V11).

[0052] The storage unit (220) can store battery cells (BC1, BC2, BC3) constituting the diagnostic circuit and the characteristics or specifications of each component. That is, the storage unit (220) stores data such as charge or discharge voltages of battery cells (BC1, BC2, BC3), current voltage states of battery cells (BC1, BC2, BC3), resistance values ​​of a plurality of first resistors (R11, R12, R13, R14) constituting the diagnostic circuit, resistance values ​​of a plurality of second resistors (R21, R22), and current values ​​of each of the battery cells (BC1, BC2, BC3) according to the resistance values ​​of the first and second resistors and the voltage values ​​of the battery cells (BC1, BC2, BC3). Additionally, the storage unit (220) can store measurement values ​​such as the voltage when cell balancing of a specific battery cell measured by the measurement unit (210) is performed and the voltage when cell balancing of the corresponding battery cell is not performed.

[0053] The comparison unit (230) compares the voltage across the first path resistance of the battery cell to be diagnosed with the voltage across the second path resistance. That is, the comparison unit (230) compares the measured value and the calculated value of the voltage across the path resistance. To this end, the comparison unit (230) first calculates the difference using the voltage when battery cell balancing of the battery cell to be diagnosed is performed and the voltage when it is not performed from the measurement unit (210). That is, the comparison unit (230) calculates the voltage across the first path resistance of the battery cell to be diagnosed. Next, the comparison unit (230) calculates the voltage across the second path resistance using the voltage of the battery cell to be diagnosed from the storage unit (220) and the resistance values ​​of the plurality of resistors provided in the output path. That is, the comparison unit (230) calculates the voltage across the second path resistance according to [Mathematical Expressions 2] to [Mathematical Expressions 4]. And, the comparison unit (230) compares the voltages across the first and second path resistors.

[0054] The judgment control unit (240) determines the measurement diagnosis result according to the comparison result of the comparison unit (230). That is, if the voltage across the first path resistor and the voltage across the second path resistor compared by the comparison unit (230) are greater than a set reference value, the judgment control unit (240) diagnoses it as a measurement error, and if it is less than the reference value, it diagnoses it as a normal measurement. At this time, in the case of being diagnosed as a measurement error, it can be determined that at least one of the plurality of first measurement pins (CT1, CT2, CT3, CT4) and the plurality of second measurement pins (CB1, CB2, CB3, CB4) is abnormal, or that an abnormality has occurred in the circuit. Meanwhile, the judgment control unit (240) can control the switches (SW11, SW12, SW13, SW14) by generating a control signal for controlling the switches (SW11, SW12, SW13, SW14). That is, the judgment control unit (240) can select a battery cell to be diagnosed and control a switch connected to the measurement pin of the battery cell to perform balancing of the battery cell.

[0055] As described above, the battery cell voltage measurement diagnosis method according to an embodiment of the present invention can compare the voltage across the first path resistor and the voltage across the second path resistor, and if the comparison result is greater than a reference value, it can be determined as a diagnosis error. At this time, the voltage across the first path resistor can be calculated by subtracting the voltage across the path resistor when balancing the battery cell to be diagnosed and the voltage across the path resistor when balancing is not performed. In addition, the voltage across the second path resistor can be calculated using the voltage of the battery cell to be diagnosed and the resistance values ​​of multiple resistors provided in the output path.

[0056] Conventional methods have the problem of not being able to diagnose anomalies in the battery cell voltage measurement circuit when both lines connected to one terminal of a battery cell are abnormal. However, the present invention compares the voltages across the first and second path resistors and determines an error based on the comparison results, thereby enabling the diagnosis of an error even when both lines connected to one terminal of a battery cell are abnormal or one is in an emergency state.

[0057] While the technical concepts of the present invention have been specifically described through the above-described embodiments, it should be noted that the embodiments are intended for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, those skilled in the art will appreciate that various embodiments are possible within the scope of the technical concepts of the present invention.

[0058] The names of each symbol used in the description and drawings of the invention are as follows.

[0059] BC1, BC2, BC3: Battery cells L11, L12, L13, L14: Line 1

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

[0061] R21, R22: Second resistor SW11, SW12, SW13, SW14: Switch

[0062] 100: Battery module 200: BMS

[0063] 210: Measurement section 220: Storage section

[0064] 230: Comparison unit 240: Judgment control unit

[0065]

Claims

1. As a diagnostic method for measuring battery cell voltage, A first path resistance cross-terminal voltage calculation process for calculating the cross-terminal voltage of a path resistance connected to the output path of a battery cell to be diagnosed; A second path resistance both-end voltage calculation process for calculating the voltage across the path resistance from the resistance value of the output path and the voltage of the battery cell to be diagnosed; A process of comparing the voltage across the first path resistor and the voltage across the second path resistor; and A battery cell voltage measurement diagnosis method including a process of diagnosing a measurement error based on the comparison results of the voltages across the first and second path resistances.

2. A battery cell voltage measurement diagnosis method according to claim 1, wherein the voltage across the first path resistance is calculated from the difference between the voltage measured when the balancing path of the battery cell to be diagnosed is set and the voltage measured when the balancing path is not set.

3. A battery cell voltage measurement diagnosis method according to claim 2, wherein the voltage across the second path resistance is calculated from 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 resistance.

4. A battery cell voltage measurement diagnosis method according to claim 3, wherein the voltage across the second path resistance is calculated by dividing the voltage of the battery cell to be diagnosed by the sum of the resistance values ​​of the output paths and multiplying by the resistance value of the path resistance.

5. A battery cell voltage measurement diagnosis method for diagnosing a voltage measurement error when the voltages across the first and second path resistors in claim 4 differ by exceeding a predetermined reference value.

6. A method for measuring battery cell voltage of a battery pack including a plurality of battery cells and a BMS, A first path resistance cross-terminal voltage calculation process for calculating the voltage across the path resistance connected to the output path of the battery cell to be diagnosed from the voltage at the output terminal of the output path; A second path resistance voltage calculation process for calculating the voltage across the path resistance from the resistance value of the output path and the voltage of the battery cell to be diagnosed; and A battery cell voltage measurement diagnosis method including a process of diagnosing a voltage measurement error when the voltage across the first and second path resistors differs by exceeding a predetermined reference value.

7. In claim 6, the first path resistor both-end voltage (V11) is a battery cell voltage measurement diagnosis method calculated from the voltage (Vx(balancing ON)) when balancing the battery cell to be diagnosed is performed and the voltage (Vx(balancing OFF)) when balancing is not performed, as in [Mathematical Formula 1]. [Mathematical Formula 1] 8. In claim 7, the voltage across the second path resistor (V12) is the voltage of the battery cell to be diagnosed (V BC1 ), a battery cell voltage measurement diagnostic method calculated from the sum of the resistance values ​​of the output path (Rm) and the resistance value of the path resistance (R12) as in [Mathematical Formula 2]. [Equation 2]

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