Battery management system that can diagnose shunt resistor failure and method of diagnosing shunt resistor failure using same

Abstract

The present invention relates to a battery management system that can diagnose a shunt resistor failure and a method of diagnosing a shunt resistor failure using same, and the battery management system may comprise: a current prediction unit for receiving the voltage of an auxiliary battery from an auxiliary battery voltage measurement unit and dividing same by the internal resistance of the auxiliary battery to predict a first current, and receiving the voltage of a main battery from a main battery voltage measurement unit and dividing same by the internal resistance of the main battery to predict a second current; and a state diagnosis unit for calculating the average of the first current and the second current, calculating a first error rate on the basis of the average and an auxiliary current, and diagnosing the state of an auxiliary shunt resistor on the basis of the calculated first error rate.

Description

Battery management system capable of diagnosing failure of shunt resistor and method for diagnosing failure of shunt resistor using the same

[0001] Cross-citation with related application(s)

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0052988, filed April 19, 2024, the entire contents of which are incorporated herein by reference.

[0003] The present invention relates to a battery management system capable of diagnosing a failure of a shunt resistor and a method for diagnosing a failure of a shunt resistor using the same.

[0004] Currently commercially available batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium batteries. The power supply systems for these batteries typically include current sensors to measure current. Current sensors monitor the battery's condition by measuring the current flowing through the battery's charge / discharge path, and detect overcurrents. The current measured by the current sensor can be used to calculate the state of charge (SOC) or as a basis for determining whether the charge / discharge process is proceeding normally.

[0005] Shunt resistors are used as components to measure current flowing through a battery, and the voltage across them can be measured to determine the current. However, if the shunt resistor malfunctions, the current flowing through the battery cannot be properly measured. Consequently, even if an abnormal situation such as overcurrent occurs, it cannot be properly blocked, which can lead to serious problems such as battery failure or explosion.

[0006] Conventionally, the status of a shunt resistor can be diagnosed by comparing the current value flowing through the shunt resistor with the current prediction value obtained based on the voltage value acquired by a cell voltage meter. However, in cases where multiple charge / discharge cases such as charge, discharge, and simultaneous charge / discharge modes are possible, that is, when two shunt resistors are used (for example, when a main shunt resistor and an auxiliary shunt resistor are used together), the conventional shunt resistor status diagnosis method can diagnose the status of the auxiliary shunt resistor only when charging is being performed through the charge path and discharging is not being performed through the discharge path. Therefore, there is a need for a method capable of diagnosing the status of the auxiliary shunt resistor regardless of the charge / discharge mode.

[0007] The present invention aims to provide a battery management system capable of diagnosing a failure of a shunt resistor in a battery system capable of charging, discharging, and charge-discharging modes and including a main shunt resistor and an auxiliary shunt resistor, and a method for diagnosing a failure of a shunt resistor using the same.

[0008] A battery management system capable of diagnosing a failure of a shunt resistor according to an embodiment of the present invention may include: an auxiliary current detection unit that detects an auxiliary current flowing in an auxiliary shunt resistor based on a voltage generated at both ends of the auxiliary shunt resistor; an auxiliary battery voltage measurement unit that is connected to a positive terminal and a negative terminal of an auxiliary battery and measures a voltage of the auxiliary battery; a main battery voltage measurement unit that is connected to a positive terminal and a negative terminal of a main battery and measures a voltage of the main battery; a current prediction unit that divides the voltage of the auxiliary battery measured by the auxiliary battery voltage measurement unit by an internal resistance of the auxiliary battery to predict a first current and divides the voltage of the main battery measured by the main battery voltage measurement unit by an internal resistance of the main battery to predict a second current; and a status diagnosis unit that calculates an average of the first current and the second current, calculates a first error rate based on the average and the auxiliary current, and diagnoses a status of the auxiliary shunt resistor based on the calculated first error rate.

[0009] The above current prediction unit can receive the auxiliary current from the auxiliary current detection unit and calculate the internal resistance of the auxiliary battery by dividing the voltage of the auxiliary battery by the auxiliary current.

[0010] It may include a main current detection unit that detects the main current flowing through the main shunt resistor based on the voltage generated at both ends of the main shunt resistor.

[0011] The above current prediction unit can receive the main current from the main current detection unit and calculate the internal resistance of the main battery by dividing the voltage of the main battery by the main current.

[0012] The above-mentioned status diagnosis unit can determine whether the auxiliary current is greater than or equal to a reference value, and if the auxiliary current is greater than or equal to the reference value, it can determine that the auxiliary shunt resistor is in an open state.

[0013] The above condition diagnosis unit can determine that the auxiliary shunt resistor is in a short state when the first error rate is greater than or equal to a predetermined threshold value, and can determine that the auxiliary shunt resistor is in a drift state when the first error rate is in a predetermined range less than the threshold value.

[0014] The above-mentioned condition diagnosis unit can calculate a second error rate based on the second current and the main current, and diagnose the condition of the main shunt resistor based on the calculated second error rate.

[0015] The above-mentioned status diagnosis unit can determine whether the main current is greater than or equal to a reference value, and if the main current is greater than or equal to the reference value, it can determine that the main shunt resistor is in an open state.

[0016] The above-mentioned condition diagnosis unit can determine that the main shunt resistor is in a short state when the second error rate is greater than or equal to a predetermined threshold value, and can determine that the main shunt resistor is in a drift state when the second error rate is in a predetermined range less than the threshold value.

[0017] In a battery system including an auxiliary shunt resistor and a main shunt resistor according to one embodiment of the present invention, a method for diagnosing a failure of the auxiliary shunt resistor and the main shunt resistor may include a step in which an auxiliary current detection unit detects an auxiliary current flowing in the auxiliary shunt resistor based on a voltage generated at both ends of the auxiliary shunt resistor, a step in which a current prediction unit predicts a first current by dividing a voltage of the auxiliary battery measured by an auxiliary battery voltage measurement unit by an internal resistance of the auxiliary battery, and a step in which a status diagnosis unit predicts a second current by dividing a voltage of the main battery measured by a main battery voltage measurement unit by an internal resistance of the main battery, a step in which a status diagnosis unit calculates an average of the first current and the second current when the auxiliary current is less than the reference value, and calculates a first error rate using the auxiliary current and the average, and a step in which the status diagnosis unit determines a status of the auxiliary shunt resistor based on the first error rate.

[0018] The step of predicting the second current may include a step in which the current prediction unit receives the auxiliary current detected through the auxiliary current detection unit and calculates the internal resistance of the auxiliary battery by dividing the voltage of the auxiliary battery by the auxiliary current, and a step in which the current prediction unit receives the main current detected based on the voltage generated across both ends of the main shunt resistor through the main current detection unit and calculates the internal resistance of the main battery by dividing the voltage of the main battery by the main current.

[0019] The step of calculating the first error rate may include a step of the state diagnosis unit determining whether the auxiliary current is greater than or equal to a predetermined reference value, and a step of determining that the auxiliary shunt resistor is in an open state when the auxiliary current is greater than or equal to the predetermined reference value.

[0020] The step of calculating the first error rate may calculate the ratio of the difference between the auxiliary current and the average of the first current and the second current to the average of the first current and the second current as the first error rate.

[0021] The step of determining the state of the auxiliary shunt resistor may include a step of determining whether the first error rate is greater than or equal to a predetermined threshold value, and a step of determining that the auxiliary shunt resistor is in a short state when the first error rate is greater than or equal to the threshold value.

[0022] The step of determining the state of the auxiliary shunt resistor may include a step of determining whether the first error rate falls within a predetermined range below a threshold value, and a step of determining that the auxiliary shunt resistor is in a drift state when the first error rate falls within a predetermined range below the threshold value.

[0023] According to an embodiment, the method may further include a step in which a main current detection unit detects a main current flowing in a main shunt resistor based on a voltage generated at both ends of the main shunt resistor, a step in which the current prediction unit predicts a second current by dividing a voltage of the main battery by an internal resistance of the main battery, a step in which a status diagnosis unit calculates a second error rate using the main current and the second current, and a step in which the status diagnosis unit determines a status of the main shunt resistor based on the second error rate.

[0024] According to one embodiment of the present invention, in a battery system including both a main shunt resistor and an auxiliary shunt resistor capable of simultaneous charging and discharging, the state of the auxiliary shunt resistor can be accurately diagnosed.

[0025] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure belongs from the description below.

[0026] FIG. 1 is a drawing illustrating a battery system according to one embodiment of the present invention.

[0027] FIG. 2 is a block diagram of a battery management system according to one embodiment of the present invention.

[0028] FIG. 3 is a flowchart of a method for diagnosing an auxiliary shunt resistor failure according to one embodiment of the present invention.

[0029] Figure 4 is a flowchart of a main shunt resistor failure diagnosis method according to one embodiment of the present invention.

[0030] In describing the embodiments disclosed in this specification, detailed descriptions of related known technologies will be omitted if it is determined that such detailed descriptions may obscure the gist of the embodiments disclosed in this specification. In addition, the attached drawings are provided solely to facilitate understanding of the embodiments disclosed in this specification, and the technical concepts disclosed in this specification are not limited by the attached drawings, and should be understood to include all modifications, equivalents, and substitutes included within the spirit and technical scope of the present invention.

[0031] Terms that include ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by these terms. These terms are used solely to distinguish one component from another.

[0032] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0033] In this application, terms such as “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the specification, but should be understood not to exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0034] The present invention will be described in detail with reference to the attached drawings below.

[0035] FIG. 1 is a drawing illustrating a battery system (1) according to one embodiment of the present invention.

[0036] Referring to FIG. 1, a battery system (1) according to one embodiment of the present invention may include a main battery (10), an auxiliary battery (2), contactors (C1 to C3), a main shunt resistor (R2), an auxiliary shunt resistor (R1), and a battery management system (20).

[0037] In Fig. 1, the main battery (10) is connected between a node (N) connecting a first power terminal (P+_DSG) and a second power terminal (P+_CHG) of the battery system (1) and a third power terminal (P-). A first contactor (C1) may be connected between the positive electrode of the main battery (10) and the node (N), a second contactor (C2) may be connected between the node (N) and the first power terminal (P+_DSG), and an auxiliary shunt resistor (R1) and a third contactor (C3) may be connected between the node (N) and the second power terminal (P+_CHG). A main shunt resistor (R2) may be connected between the negative electrode of the main battery (10) and the third power terminal (P-), and a ground may be provided. In the present disclosure, the potential of the positive electrode is higher than the potential of the negative electrode.

[0038] The main battery (10) is a secondary battery capable of charging, discharging, and recharging. Depending on the embodiment, the main battery (10) may include a plurality of battery cells electrically connected in series and parallel.

[0039] The auxiliary battery (2) is a charger for supplying power to and charging the main battery (10). Depending on the embodiment, the auxiliary battery (2) may include a plurality of battery cells electrically connected in series and parallel, and may be a secondary battery capable of being charged and discharged. The electrical connection between the auxiliary battery (2) and the main battery (10) is controlled through the ON / OFF operations of the first contactor (C1) and the third contactor (C3).

[0040] The contactors (C1 to C3) serve as a kind of switch that controls the connection between the main battery (10) and the auxiliary battery (2) and the connection between the main battery (10) and the external device (3). For example, in FIG. 1, when the first contactor (C1) and the third contactor (C3) are turned on, the main battery (10) and the auxiliary battery (2) are electrically connected, and the main battery (10) is charged, and when the first contactor (C1) and the second contactor (C2) are turned on, the main battery (10) and the external device (3) are connected, and the main battery (10) is discharged. At this time, the external device (3) may be a load such as a vehicle. According to an embodiment, the contactor may include first to third contactors (C1 to C3), and the first to third contactors (C1 to C3) may be relays or MOSFETs.

[0041] The main shunt resistor (R2) is a shunt resistor element for detecting a current flowing at a specific point within the battery system (1) when the main battery (10) is being charged and / or discharged. According to an embodiment, the main shunt resistor (R2) can detect a current flowing between the negative pole of the main battery (10) and the third power terminal (P-) when the main battery (10) is being discharged by the external device (3) according to the ON operation of the first contactor (C1) and the second contactor (C2), i.e., when a discharge cycle is in progress. In addition, the main shunt resistor (R2) can detect a current flowing between the negative pole of the main battery (10) and the third power terminal (P-) when the main battery (10) is being charged by the auxiliary battery (2) according to the ON operation of the first contactor (C1) and the third contactor (C3), i.e., when a charge cycle is in progress. In Fig. 1, the main shunt resistor (R2) is shown as being connected between the negative pole of the main battery (10) and the third power terminal (P-), but the position where the main shunt resistor (R2) is connected is not limited thereto, and can be freely changed as long as the current flowing in the main battery (10) during charging and / or discharging of the main battery (10) can be measured.

[0042] The auxiliary shunt resistor (R1) is a shunt resistor element for detecting a current flowing at a specific point within the battery system (1) when the main battery (10) is being charged. According to an embodiment, the auxiliary shunt resistor (R1) can detect a current flowing between the node (N) and the third contactor (C3) when the main battery (10) is being charged by the auxiliary battery (2), i.e., when a charging cycle is in progress, according to the ON operation of the first contactor (C1) and the third contactor (C3). In Fig. 1, the auxiliary shunt resistor (R1) is illustrated as being connected between the node (N) and the third contactor (C3), but the position at which the auxiliary shunt resistor (R1) is connected is not limited thereto, and can be freely changed as long as the current flowing in the auxiliary battery (2) while the main battery (10) is being charged can be measured.

[0043] The battery management system (20) (BMS) may include an auxiliary current detection unit (21), a control unit (22), an auxiliary battery voltage measurement unit (26), and a main battery voltage measurement unit (27). Here, the control unit (22) may include a current prediction unit (23) and a status diagnosis unit (24). According to an embodiment, the battery management system (20) may further include a main current detection unit (25).

[0044] The auxiliary current detection unit (21), the main current detection unit (25), the auxiliary battery voltage measurement unit (26), and the main battery voltage measurement unit (27) can transmit and receive signals with the control unit (22) by a wired or wireless communication method. For example, the control unit (22) can generate a control signal and transmit it to the auxiliary current detection unit (21), the main current detection unit (25), the auxiliary battery voltage measurement unit (26), and the main battery voltage measurement unit (27), and the auxiliary current detection unit (21), the main current detection unit (25), the auxiliary battery voltage measurement unit (26), and the main battery (10) measurement unit can detect or measure the auxiliary current, the main current, the voltage of the auxiliary battery (2), and the voltage of the main battery (10), respectively, according to the control signal. In addition, the auxiliary current detection unit (21) can detect the auxiliary current and transmit it to the control unit (22), and the main current detection unit (25) can detect the main current and transmit it to the control unit (22). In addition, the auxiliary battery voltage measurement unit (26) can measure the voltage of the auxiliary battery (2) and transmit it to the control unit (22), and the main battery voltage measurement unit (27) can measure the voltage of the main battery (10) and transmit it to the control unit (22).

[0045] That is, the battery management system (20) can measure the voltage, current, temperature, etc. of the main battery (10) and can measure the voltage, current, temperature, etc. of the auxiliary battery (2). In addition, the battery management system (20) can diagnose the status of the main shunt resistor (R2) and the auxiliary shunt resistor (R1) using the voltage, current, and temperature of the main battery (10) and the voltage, current, and temperature of the auxiliary battery (2).

[0046] A battery management system (20) according to one embodiment of the present invention will be described in detail below with reference to FIG. 2.

[0047] Figure 2 is a block diagram of a battery management system (20) according to one embodiment of the present invention.

[0048] Referring to FIGS. 1 and 2, the auxiliary current detection unit (21) detects the auxiliary current flowing in the auxiliary shunt resistor (R1) based on the voltage generated across the two terminals of the auxiliary shunt resistor (R1). For example, the auxiliary current detection unit (21) can measure the voltage generated across the two terminals of the auxiliary shunt resistor and divide the measured voltage value by the resistance value of the auxiliary shunt resistor (R1) to detect the auxiliary current flowing in the auxiliary shunt resistor (R1). At this time, the resistance value of the auxiliary shunt resistor (R1) may be stored in the memory (28) or the auxiliary current detection unit (21) as a value known in advance.

[0049] The main current detection unit (25) detects the main current flowing in the main shunt resistor (R2) based on the voltage generated across the two terminals of the main shunt resistor (R2). For example, the main current detection unit (25) can measure the voltage generated across the two terminals of the main shunt resistor and divide the measured voltage value by the resistance value of the main shunt resistor (R2) to detect the main current flowing in the main shunt resistor (R2). At this time, the resistance value of the main shunt resistor (R2) may be stored in the memory (28) or the main current detection unit (25) as a value known in advance.

[0050] The auxiliary battery voltage measuring unit (26) is connected to the positive and negative terminals of the auxiliary battery (2) and measures the voltage of the auxiliary battery (2). Here, the voltage of the auxiliary battery (2) means the voltage difference between the positive and negative terminals of the auxiliary battery (2).

[0051] The main battery voltage measuring unit (27) is connected to the positive and negative terminals of the main battery (10) and measures the voltage of the main battery (10). Here, the voltage of the main battery (10) means the voltage difference between the positive and negative terminals of the main battery (10).

[0052] The current prediction unit (23) can predict the first current using the voltage and internal resistance of the auxiliary battery (2), and can predict the second current using the voltage and internal resistance of the main battery (10). For example, the current prediction unit (23) can predict the first current by dividing the voltage of the auxiliary battery (2) measured through the auxiliary battery voltage measurement unit (26) by the internal resistance of the auxiliary battery (2). The current prediction unit (23) can predict the second current by dividing the voltage of the main battery (10) measured through the main battery voltage measurement unit (27) by the internal resistance of the main battery (10).

[0053] At this time, the voltage of the auxiliary battery (2) is received from the auxiliary battery voltage measuring unit (26), and the voltage of the main battery (10) is received from the main battery voltage measuring unit (27). Depending on the embodiment, the internal resistance of the auxiliary battery (2) and the internal resistance of the main battery (10) may be data recorded in the memory (28) or values ​​calculated by the current prediction unit (23).

[0054] For example, the current prediction unit (23) may receive the auxiliary current from the auxiliary current detection unit (21) and the voltage of the auxiliary battery (2) from the auxiliary battery voltage measurement unit (26), respectively, and then divide the voltage of the auxiliary battery (2) by the auxiliary current to calculate the internal resistance of the auxiliary battery (2). Alternatively, the current prediction unit (23) may receive the temperature measurement value of the auxiliary battery (2) measured by the sensing unit (29), and detect the internal resistance of the auxiliary battery (2) according to the temperature measurement value from a table stored in the memory (28), thereby determining the internal resistance of the auxiliary battery (2). At this time, a table listing the internal resistance values ​​according to the temperature value of the auxiliary battery (2) may be stored in the memory (28).

[0055] For example, the current prediction unit (23) may receive the main current from the main current detection unit (25) and the voltage of the main battery (10) from the main battery voltage measurement unit (27), respectively, and then divide the voltage of the main battery (10) by the main current to calculate the internal resistance of the main battery (10). Alternatively, the current prediction unit (23) may receive the temperature measurement value of the main battery (10) measured by the sensing unit (29), and detect the internal resistance of the main battery (10) according to the temperature measurement value from a table stored in the memory (28), thereby determining the internal resistance of the main battery (10). At this time, a table listing internal resistance values ​​according to the temperature value of the main battery (10) may be stored in the memory (28).

[0056] The status diagnosis unit (24) can calculate the average of the first current and the second current, and can use this to calculate the first error rate.

[0057] Here, the first error rate corresponds to a criterion used to diagnose the status of the auxiliary shunt resistor (R1), and the status diagnosis unit (24) can derive the first error rate using the average value of the auxiliary current and the first and second currents. For example, the status diagnosis unit (24) can calculate the first error rate as the ratio of the difference value between the auxiliary current and the average of the first and second currents to the average of the first and second currents, as in mathematical expression 1.

[0058]

[0059] The status diagnosis unit (24) can determine the status of the auxiliary shunt resistor (R1) based on the first error rate. For example, the status diagnosis unit (24) can determine whether the auxiliary current is greater than or equal to a reference value, and if the auxiliary current is greater than or equal to the reference value, determine that the auxiliary shunt resistor (R1) is in an open state (OPEN). The reference value can be determined based on the current range that the auxiliary current can have and the value of the auxiliary shunt resistor in the open state.

[0060] In addition, the state diagnosis unit (24) can determine whether the first error rate is equal to or greater than a predetermined threshold value, and if the first error rate is equal to or greater than the threshold value, it can determine that the auxiliary shunt resistor (R1) is in a short state. The threshold value can be set to any value within a range from 100% to a ratio obtained by subtracting a predetermined margin from 100%. In addition, the state diagnosis unit (24) can determine whether the first error rate is within a predetermined range less than the threshold value, and if the first error rate is within the predetermined range, it can determine that the auxiliary shunt resistor (R1) is in a DRIFT state. The predetermined range can be determined based on the ranges that each of the first current, the second current, and the auxiliary current has in the drift state of the auxiliary shunt resistor (R1).

[0061] According to the embodiment, the state diagnosis unit (24) can calculate the second error rate based on the second current and the main current.

[0062] Here, the second error rate corresponds to a criterion used to diagnose the status of the main shunt resistor (R2), and the status diagnosis unit (24) can derive the second error rate using the main current and the second current. For example, the status diagnosis unit (24) can calculate the second error rate as the ratio of the difference between the main current and the second current compared to the second current, as in mathematical expression 2.

[0063]

[0064] According to an embodiment, the status diagnosis unit (24) can diagnose the status of the main shunt resistor (R2) based on the second error rate. For example, the status diagnosis unit (24) can determine whether the main current is greater than or equal to a reference value, and if the main current is greater than or equal to the reference value, determine that the main shunt resistor (R2) is in an open state. The reference value can be determined based on a current range that the main current can have and the value of the main shunt resistor (R2) in the open state.

[0065] In addition, the state diagnosis unit (24) can determine whether the second error rate is greater than or equal to a predetermined threshold value, and if the second error rate is greater than or equal to the threshold value, it can determine that the main shunt resistor (R2) is in a short-circuit state. The threshold value can be set to any value within a range from 100% to a ratio obtained by subtracting a predetermined margin from 100%. In addition, the state diagnosis unit (24) can determine whether the second error rate is within a predetermined range less than the threshold value, and if the second error rate is within the predetermined range, it can determine that the main shunt resistor (R2) is in a drift state. The predetermined range can be determined based on the ranges that the main current and the second current each have in the drift state of the main shunt resistor (R2).

[0066] FIG. 3 is a flowchart of a method for diagnosing a failure of an auxiliary shunt resistor (R1) according to one embodiment of the present invention, and FIG. 4 is a flowchart of a method for diagnosing a failure of a main shunt resistor (R2) according to one embodiment of the present invention.

[0067] Referring to FIGS. 3 and 4, a method for diagnosing a failure of a shunt resistor according to an embodiment of the present invention may include a method for diagnosing a failure of an auxiliary shunt resistor (R1) and / or a method for diagnosing a failure of a main shunt resistor (R2). That is, the method according to an embodiment of the present invention can diagnose the status of an auxiliary shunt resistor (R1) and / or a main shunt resistor (R2) in a battery system (1) including the auxiliary shunt resistor (R1) and the main shunt resistor (R2).

[0068] Referring to FIG. 3, a method for diagnosing a fault in an auxiliary shunt resistor (R1) according to one embodiment of the present invention may include an auxiliary current detection step (S110), a current prediction step (S120), an error rate calculation step (S130), and a status diagnosis step (S140).

[0069] In the auxiliary current detection step (S110), the auxiliary current detection unit (21) detects the auxiliary current flowing through the auxiliary shunt resistor (R1) based on the voltage generated at both ends of the auxiliary shunt resistor (R1). At this time, the detected auxiliary current can be transmitted to the control unit (22).

[0070] In the current prediction step (S120), the current prediction unit (23) uses the voltage and internal resistance of the auxiliary battery (2) and the voltage and internal resistance of the main battery (10) to predict the first current and the second current, respectively. For example, the current prediction unit (23) can predict the first current by dividing the voltage of the auxiliary battery (2) measured through the auxiliary battery voltage measurement unit (26) by the internal resistance of the auxiliary battery (2) (S121). The current prediction unit (23) can predict the second current by dividing the voltage of the main battery (10) measured through the main battery voltage measurement unit (27) by the internal resistance of the main battery (10) (S122).

[0071] According to an embodiment, the internal resistance of the auxiliary battery (2) can be derived using the auxiliary current or the temperature measurement value of the auxiliary battery (2). For example, the current prediction unit (23) can receive the auxiliary current from the auxiliary current detection unit (21) and the voltage of the auxiliary battery (2) from the auxiliary battery voltage measurement unit (26), respectively, and then divide the voltage of the auxiliary battery (2) by the auxiliary current to calculate the internal resistance of the auxiliary battery (2). In addition, the current prediction unit (23) can receive the temperature measurement value of the auxiliary battery (2) measured by the sensing unit (29), and detect the internal resistance of the auxiliary battery (2) according to the temperature measurement value from a table stored in the memory (28), thereby determining the internal resistance of the auxiliary battery (2). At this time, a table listing internal resistance values ​​according to the temperature value of the auxiliary battery (2) can be stored in the memory (28).

[0072] According to an embodiment, the internal resistance of the main battery (10) may be derived using the main current or the temperature measurement value of the main battery (10). For example, the current prediction unit (23) may receive the main current from the main current detection unit (25) and the voltage of the main battery (10) from the main battery voltage measurement unit (27), respectively, and then divide the voltage of the main battery (10) by the main current to calculate the internal resistance of the main battery (10). Here, the main current may be detected based on the voltage generated across the main shunt resistor (R2) through the main current detection unit (25). In addition, the current prediction unit (23) may receive the temperature measurement value of the main battery (10) measured by the sensing unit (29), detect the internal resistance of the main battery (10) according to the temperature measurement value from a table stored in the memory (28), and determine this as the internal resistance of the main battery (10). At this time, a table listing the internal resistance values ​​according to the temperature value of the main battery (10) can be stored in the memory (28).

[0073] In the error rate calculation step (S130), the state diagnosis unit (24) can calculate the average of the first current and the second current (S133), and the state diagnosis unit (24) can calculate the first error rate using the auxiliary current and the average of the first and second currents (S134). At this time, the state diagnosis unit (24) can receive the first current and the second current from the current prediction unit (23), and the auxiliary current from the auxiliary current detection unit (21).

[0074] Here, the first error rate corresponds to a criterion used to diagnose the status of the auxiliary shunt resistor (R1), and the status diagnosis unit (24) can derive the first error rate using the average value of the auxiliary current and the first and second currents. For example, the status diagnosis unit (24) can calculate the first error rate as the ratio of the difference value between the auxiliary current and the average of the first and second currents compared to the average of the first and second currents.

[0075] According to an embodiment, in the error rate calculation step (S130), the status diagnosis unit (24) can determine whether the auxiliary current is greater than or equal to a reference value (S131). At this time, if the auxiliary current is greater than or equal to a preset reference value, the status diagnosis unit (24) can determine that the auxiliary shunt resistor (R1) is in an open state (S132). That is, if the auxiliary current is greater than or equal to a preset reference value, the status diagnosis unit (24) can diagnose the state of the auxiliary shunt resistor (R1) without calculating the first error rate.

[0076] In the status diagnosis step (S140), the status diagnosis unit (24) can determine the status of the auxiliary shunt resistor (R1) based on the first error rate.

[0077] According to an embodiment, the state diagnosis step (S140) may include a short determination step (S141, S142) and a drift determination step (S143, S144). For example, in the state diagnosis step (S140), the state diagnosis unit (24) may determine whether the auxiliary shunt resistor (R1) is in a short state through a step (S141) of determining whether the first error rate is equal to or greater than a predetermined threshold value, and a step (S142) of determining that the auxiliary shunt resistor (R1) is in a short state if the first error rate is equal to or greater than the predetermined threshold value. In addition, in the state diagnosis step (S140), the state diagnosis unit (24) may determine whether the auxiliary shunt resistor (R1) is in a drift state through a step (S143) of determining whether the first error rate is in a predetermined range less than the threshold value, and a step (S144) of determining that the auxiliary shunt resistor (R1) is in a drift state if the first error rate is in the predetermined range less than the threshold value.

[0078] FIG. 4 is a flowchart of a main shunt resistor (R2) failure diagnosis method according to one embodiment of the present invention.

[0079] Referring to FIG. 4, a main shunt resistor (R2) fault diagnosis method according to one embodiment of the present invention may include a main current detection step (S210), a current prediction step (S220), an error rate calculation step (S230), and a status diagnosis step (S240).

[0080] In the main current detection step (S210), the main current detection unit (25) detects the main current flowing through the main shunt resistor (R2) based on the voltage generated across both terminals of the main shunt resistor (R2). At this time, the detected main current can be transmitted to the control unit (22).

[0081] In the current prediction step (S220), the current prediction unit (23) predicts the second current using the voltage and internal resistance of the main battery (10). For example, the current prediction unit (23) can predict the second current by dividing the voltage of the main battery (10) measured through the main battery voltage measurement unit (27) by the internal resistance of the main battery (10) (S220).

[0082] According to an embodiment, the internal resistance of the main battery (10) may be derived using the main current or the temperature measurement value of the main battery (10). For example, the current prediction unit (23) may receive the main current from the main current detection unit (25) and the voltage of the main battery (10) from the main battery voltage measurement unit (27), respectively, and then divide the voltage of the main battery (10) by the main current to calculate the internal resistance of the main battery (10). In addition, the current prediction unit (23) may receive the temperature measurement value of the main battery (10) measured by the sensing unit (29), and detect the internal resistance of the main battery (10) according to the temperature measurement value from a table stored in the memory (28), thereby determining the internal resistance of the main battery (10). At this time, a table listing internal resistance values ​​according to the temperature value of the main battery (10) may be stored in the memory (28).

[0083] In the error rate calculation step (S230), the status diagnosis unit (24) can calculate the second error rate using the second current and the main current (S233). At this time, the status diagnosis unit (24) can receive the second current from the current prediction unit (23) and the main current from the main current detection unit (25).

[0084] Here, the second error rate corresponds to a criterion used to diagnose the status of the main shunt resistor (R2), and the status diagnosis unit (24) can derive the second error rate using the main current and the second current. For example, the status diagnosis unit (24) can calculate the second error rate as the ratio of the difference between the main current and the second current compared to the second current.

[0085] According to an embodiment, in the error rate calculation step (S230), the status diagnosis unit (24) can determine whether the main current is greater than or equal to a reference value (S231). At this time, if the main current is greater than or equal to a preset reference value, the status diagnosis unit (24) can determine that the main shunt resistor (R2) is in an open state (S232). That is, if the main current is greater than or equal to a preset reference value, the status diagnosis unit (24) can diagnose the state of the main shunt resistor (R2) without calculating the second error rate.

[0086] In the status diagnosis step (S240), the status diagnosis unit (24) can determine the status of the main shunt resistor (R2) based on the second error rate.

[0087] According to an embodiment, the status diagnosis step (S240) may include a short determination step (S241, S242) and a drift determination step (S243, S244). For example, in the status diagnosis step (S240), the status diagnosis unit (24) may determine whether the main shunt resistor (R2) is in a short state through a step (S241) of determining whether the second error rate is equal to or greater than a predetermined threshold value, and a step (S242) of determining that the main shunt resistor (R2) is in a short state if the first error rate is equal to or greater than the predetermined threshold value. In addition, in the status diagnosis step (S240), the status diagnosis unit (24) may determine whether the main shunt resistor (R2) is in a drift state through a step (S243) of determining whether the second error rate is within a predetermined range less than the threshold value, and a step (S244) of determining that the main shunt resistor (R2) is in a drift state if the second error rate is within the predetermined range less than the threshold value.

[0088] Meanwhile, the above-described method can be written as a program that can be executed on a computer, and can be implemented on a general-purpose digital computer that operates the program using a computer-readable recording medium. The computer-readable recording medium may include a storage medium such as a magnetic storage medium such as a ROM, RAM, USB, floppy disk, or hard disk, or an optical readable medium such as a CD-ROM or DVD.

[0089] The scope of the present invention is indicated by the claims described below rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

Claims

1. An auxiliary current detection unit that detects an auxiliary current flowing through an auxiliary shunt resistor based on a voltage generated at both ends of the auxiliary shunt resistor; An auxiliary battery voltage measuring unit connected to the positive and negative terminals of the auxiliary battery and measuring the voltage of the auxiliary battery; A main battery voltage measuring unit connected to the positive and negative terminals of the main battery and measuring the voltage of the main battery; A current prediction unit that predicts a first current by dividing the voltage of the auxiliary battery measured by the auxiliary battery voltage measurement unit by the internal resistance of the auxiliary battery, and predicts a second current by dividing the voltage of the main battery measured by the main battery voltage measurement unit by the internal resistance of the main battery; and A condition diagnosis unit that calculates an average of the first current and the second current, calculates a first error rate based on the average and the auxiliary current, and diagnoses the condition of the auxiliary shunt resistor based on the calculated first error rate; Battery management system.

2. In paragraph 1, The above current prediction unit, Receives the auxiliary current from the auxiliary current detection unit, and calculates the internal resistance of the auxiliary battery by dividing the voltage of the auxiliary battery by the auxiliary current. Battery management system.

3. In paragraph 1, Including a main current detection unit that detects the main current flowing through the main shunt resistor based on the voltage generated at both ends of the main shunt resistor. Battery management system.

4. In paragraph 3, The above current prediction unit, Receives the main current from the main current detection unit, and calculates the internal resistance of the main battery by dividing the voltage of the main battery by the main current. Battery management system.

5. In paragraph 1, The above condition diagnosis unit, It is determined whether the above auxiliary current is greater than or equal to the reference value, and if the above auxiliary current is greater than or equal to the reference value, it is determined that the above auxiliary shunt resistor is in an open state. Battery management system.

6. In paragraph 1, The above condition diagnosis unit, If the first error rate is greater than or equal to a predetermined threshold value, it is determined that the auxiliary shunt resistor is in a short state, and if the first error rate is in a predetermined range less than the threshold value, it is determined that the auxiliary shunt resistor is in a drift state. Battery management system.

7. In paragraph 3, The above condition diagnosis unit, A second error rate is calculated based on the second current and the main current, and the status of the main shunt resistor is diagnosed based on the calculated second error rate. Battery management system.

8. In paragraph 7, The above condition diagnosis unit, It is determined whether the above main current is greater than or equal to the reference value, and if the above main current is greater than or equal to the reference value, it is determined that the above main shunt resistor is in an open state.

9. In paragraph 7, The above condition diagnosis unit, If the second error rate is greater than or equal to a predetermined threshold value, the main shunt resistor is determined to be in a short state, and if the second error rate is within a predetermined range less than the threshold value, the main shunt resistor is determined to be in a drift state. Battery management system.

10. In a battery system including an auxiliary shunt resistor and a main shunt resistor, a method for diagnosing a failure of the auxiliary shunt resistor and the main shunt resistor, A step of detecting an auxiliary current flowing through the auxiliary shunt resistor based on a voltage generated at both ends of the auxiliary shunt resistor by the auxiliary current detection unit; A step of predicting a first current by dividing the voltage of the auxiliary battery measured by the auxiliary battery voltage measuring unit by the internal resistance of the auxiliary battery, and predicting a second current by dividing the voltage of the main battery measured by the main battery voltage measuring unit by the internal resistance of the main battery; A step of the status diagnosis unit calculating an average of the first current and the second current when the auxiliary current is less than the reference value, and calculating a first error rate using the auxiliary current and the average; and The above condition diagnosis unit includes a step of determining the condition of the auxiliary shunt resistor based on the first error rate. Method for diagnosing faults in shunt resistors.

11. In paragraph 10, The step of predicting the above second current is: A step in which the current prediction unit receives the auxiliary current detected through the auxiliary current detection unit and calculates the internal resistance of the auxiliary battery by dividing the voltage of the auxiliary battery by the auxiliary current; and The current prediction unit includes a step of receiving the main current detected based on the voltage generated at both ends of the main shunt resistor through the main current detection unit, and calculating the internal resistance of the main battery by dividing the voltage of the main battery by the main current. Method for diagnosing faults in shunt resistors.

12. In paragraph 10, The step of calculating the above first error rate is: The above-mentioned state diagnosis unit determines whether the auxiliary current is greater than a predetermined reference value; and A step of determining that the auxiliary shunt resistor is in an open state when the auxiliary current is greater than a predetermined reference value, Method for diagnosing faults in shunt resistors.

13. In paragraph 10, The step of calculating the above first error rate is: The ratio of the difference between the auxiliary current and the average of the first current and the second current to the average of the first current and the second current is calculated as the first error rate. Method for diagnosing faults in shunt resistors.

14. In paragraph 10, The step of judging the status of the above auxiliary shunt resistor is: A step of determining whether the first error rate is greater than or equal to a predetermined threshold; and Including a step of determining that the auxiliary shunt resistor is in a short state when the first error rate is greater than or equal to the threshold value. Method for diagnosing faults in shunt resistors.

15. In paragraph 10, The step of judging the status of the above auxiliary shunt resistor is: A step of determining whether the first error rate falls within a predetermined range below the threshold value; and Including a step of determining that the auxiliary shunt resistor is in a drift state when the first error rate is within a predetermined range below the threshold value. Method for diagnosing faults in shunt resistors.

16. In paragraph 10, A step in which a main current detection unit detects a main current flowing through a main shunt resistor based on a voltage generated at both ends of the main shunt resistor; A step in which the current prediction unit predicts a second current by dividing the voltage of the main battery by the internal resistance of the main battery; A step of calculating a second error rate using the main current and the second current by the status diagnosis unit; and The above condition diagnosis unit further includes a step of determining the condition of the main shunt resistor based on the second error rate. Method for diagnosing faults in shunt resistors.

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