Method of determining pre-charge resistor anomalies and battery system using same

Abstract

A battery system includes at least one battery pack including a plurality of battery cells, a plurality of pre-charge resistors connected to one end of the at least one battery pack, a plurality of pre-charge switches having one end connected to the other end of the plurality of pre-charge resistors, a plurality of capacitors connected to the other end of the plurality of pre-charge switches, and a main control circuit that determines whether the plurality of pre-charge resistors are abnormal based on a result of comparing a sum of a plurality of branch circuit currents calculated by using a plurality of pre-stored resistance values of the plurality of pre-charge resistors and a voltage applied across the plurality of pre-charge resistors with a battery current flowing through the at least one battery pack when a first period of time elapses during a pre-charge operation. One of the plurality of pre-charge resistors, the pre-charge switch connected to the other end of the one pre-charge resistor, and the capacitor constitute one branch.

Description

Technical Field

[0001] Cross-reference to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2020-0117949, filed on September 14, 2020, with the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference.

[0003] This disclosure relates to a method for determining a precharge resistor malfunction and a battery system using the method. Background Technology

[0004] As the pre-charge resistor deteriorates, its resistance increases. Consequently, the charging time of the pre-charge capacitor connected to the pre-charge resistor is prolonged, and the transition to drive mode may be delayed during vehicle ignition when receiving power from the battery system.

[0005] Furthermore, when a battery system comprises multiple battery packs connected in parallel, high current can flow through the high-voltage load branch connected in parallel with the battery system to branches other than those connected to the degraded pre-charge resistor. The heat generated by this high current may then damage the protection circuitry.

[0006] Furthermore, in high-load loads connected to the battery system, insulation may be compromised due to damage to the pre-charge resistor. Deterioration of the pre-charge resistor can reduce the internal resistance of loads in branches connected to high-load loads, where smaller currents than specified flow. Summary of the Invention

[0007] Technical issues

[0008] This disclosure provides a method for determining whether a pre-charge resistor is abnormal and a battery system using the method.

[0009] Technical solution

[0010] According to one aspect of the present invention, a battery system includes: a plurality of battery packs, the plurality of battery packs including a plurality of battery cells; a plurality of pre-charge resistors, wherein one terminal of each of the plurality of pre-charge resistors is connected to one terminal of each of the plurality of battery packs; a plurality of pre-charge switches, wherein one terminal of each of the plurality of pre-charge switches is connected to another terminal of each of the plurality of pre-charge resistors; a plurality of capacitors, wherein one terminal of each of the plurality of capacitors is connected to another terminal of each of the plurality of pre-charge switches; and a main control circuit, which, during the execution of the pre-charge operation, after a first period of time, determines whether the plurality of pre-charge resistors are abnormal based on a comparison of the sum of a plurality of branch circuits calculated using pre-stored values ​​of the plurality of resistors and the voltages at two terminals of the plurality of pre-charge resistors with the battery current flowing through at least one battery pack. One of the plurality of pre-charge resistors, the pre-charge switch, and the capacitor connected to the other terminal of one of the pre-charge resistors constitute a branch.

[0011] The main control circuit calculates the charging slope of multiple branches and determines, based on the difference between the capacitor voltages of multiple capacitors that have passed the second time period during the pre-charging operation and the capacitor voltages of multiple capacitors that have passed the first time period, that the pre-charging resistor of the branch with a charging slope smaller than a predetermined reference slope among the multiple branch charging slopes is abnormal.

[0012] The reference slope can be the branch charging slope when each of the plurality of pre-charge resistors is in a normal state.

[0013] The main control circuit can measure the charging time of multiple branches where the voltage of each of the multiple capacitors reaches the voltage of at least one battery pack, and can determine that the pre-charge resistor of the branch with a charging time longer than a predetermined reference time is abnormal.

[0014] The reference time can be the branch charging time when each of the multiple pre-charge resistors is in a normal state.

[0015] The first time period may be a time period corresponding to a time constant determined by the resistance value of each of the plurality of pre-charge resistors and the capacitance of each of the plurality of capacitors, and the second time period may be a time period corresponding to a predetermined integer multiple of the time constant.

[0016] According to another aspect of the present invention, a method for determining an anomaly in a pre-charge resistor of a battery system, the battery system comprising a plurality of battery packs containing a plurality of battery cells, a plurality of pre-charge resistors, a plurality of pre-charge switches, and a plurality of capacitors, the method comprising the steps of: calculating a plurality of branch currents using the voltages at two terminals of the plurality of pre-charge resistors after a first time period has elapsed during the execution of the pre-charge operation and a plurality of pre-stored resistance values ​​of the plurality of pre-charge resistors; initially comparing the sum of the plurality of branch currents with the battery current flowing through at least one of the battery packs; and if, as a result of the initial comparison, the sum of the plurality of branch currents differs from the battery current, determining that at least one of the plurality of pre-charge resistors is an anomaly. One of the plurality of pre-charge resistors, the pre-charge switch, and a capacitor connected to the other terminal of one of the pre-charge resistors constitute a branch. One terminal of each of the plurality of pre-charge resistors may be connected to one terminal of each of the plurality of battery packs, one terminal of each of the plurality of pre-charge switches may be connected to the other terminal of each of the plurality of pre-charge resistors, and one terminal of each of the plurality of capacitors may be connected to the other terminal of each of the plurality of pre-charge switches.

[0017] The method for determining the abnormality of the pre-charge resistor of the battery system may further include the following steps: calculating a plurality of branch charging slopes based on the difference between a plurality of capacitor voltages of a plurality of capacitors during a second time period and a plurality of capacitor voltages of a plurality of capacitors during a first time period; comparing each of the plurality of branch charging slopes with a predetermined reference slope for the second time; and determining, as a result of the second comparison, that the pre-charge resistor of the branch having a branch charging slope larger than the reference slope is abnormal.

[0018] The method for determining an anomaly in the pre-charge resistor of the battery system may further include: measuring the charging time of a plurality of branches, wherein during the plurality of branch charging times, the voltage charged into each of the plurality of capacitors reaches the voltage of at least one battery pack; comparing the plurality of branch charging times a third time with a predetermined reference time; and, as a result of the third comparison, determining that the pre-charge resistor of the branch having a branch charging time longer than the reference time is an anomaly.

[0019] Beneficial effects

[0020] A method for determining whether a pre-charge resistor is abnormal and a battery system for applying this method are provided. Attached Figure Description

[0021] Figure 1 This is a diagram illustrating the configuration of a battery system according to an embodiment.

[0022] Figure 2 This is a diagram illustrating a method for detecting the degradation of a pre-charge resistor during pre-charge operation according to an embodiment.

[0023] Figure 3 It is a graph showing the voltage fluctuation of one of a plurality of capacitors during pre-charge operation according to an embodiment. Detailed Implementation

[0024] The embodiments disclosed in this specification will be described in detail below with reference to the accompanying drawings. In this specification, identical or similar components will be denoted by identical or similar reference numerals, and repeated descriptions thereof will be omitted. The terms "module" and "unit" used for components in the following description are for ease of explanation only. Therefore, these terms do not have the meaning or function of distinguishing them from each other. Furthermore, in describing embodiments of this specification, detailed descriptions of well-known techniques associated with the invention will be omitted when it is determined that such detailed descriptions may obscure the gist of the invention. Additionally, the accompanying drawings are provided only to facilitate the understanding of the embodiments disclosed in this specification and are not to be construed as limiting the spirit of the disclosure herein. It is to be understood that the invention includes all modifications, equivalents, and substitutions that do not depart from the scope and spirit of the invention.

[0025] Ordinal terms such as first, second, etc., will only be used to describe various components and will not be interpreted as limiting these components. These terms are only used to distinguish one component from others.

[0026] To understand this, when a component is referred to as "connected" or "linked" to another component, it can be directly connected or linked to the other component, or there can be other intermediate components connecting or linking to the other component. On the other hand, to understand this, when a component is referred to as "directly connected or linked" to another component, it can be connected or linked to the other component without any other intermediate components.

[0027] It will also be understood that the terms “comprising” or “having” as used in this specification specify the presence of the said feature, number, step, operation, component, part or combination thereof, but do not exclude the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0028] Figure 1 This is a diagram illustrating the configuration of a battery system according to an embodiment.

[0029] The battery system 1 includes multiple battery packs 10 to 30, a main control circuit (MCU) 40, and a relay device 50. Figure 1The diagram shows a number of battery packs, specifically three, but the invention is not limited to this, and the battery system 1 may include four or more battery packs. Additionally, in Figure 1 In this example, multiple battery packs 10 to 30 are illustrated as being connected in parallel, but two or more battery packs may be connected in series, and multiple battery packs connected in series may be connected in parallel.

[0030] Vehicle 2 includes an inverter 201, an Electric Power Take-Off (EPTO) 202, and a high-speed charger 203. EPTO 202 may include a battery, an electric motor, a hydraulic pump, an intelligent electronic control system, etc. Figure 1 An example of a configuration of vehicle 2 connected to battery system 1 is shown, and other configurations such as a DC-DC converter for 12V, a DC-DC converter for 24V, and an on-board charger (OBC) can also be connected.

[0031] Multiple battery packs 10 to 30 are connected in parallel with each other, and two terminals of the multiple battery packs 10 to 30 are respectively connected to the relay device 50 via lines 101 and 102.

[0032] Each of the multiple battery packs 10 to 30 includes multiple battery cells 11 to 15, 21 to 25 and 31 to 35, multiple battery pack management systems 100 to 300, and current sensors 16, 26 and 36. Hereinafter, the battery pack management system is referred to as the battery pack management system (BMS). Figure 1 The illustration shows each of several battery packs 10 to 30 comprising five battery cells 11 to 15, 21 to 25, and 31 to 35 (this is an example), but the invention is not limited thereto. Additionally, although in Figure 1 Not shown, but the relay may be connected between at least one end of each of the plurality of battery packs 10 to 30 and at least one corresponding line of the two lines 101 and 102.

[0033] Each of the multiple battery pack BMS100 to 300 is connected to multiple battery cells 11 to 15, 21 to 25, and 31 to 35, and measures the cell voltage of the multiple battery cells 11 to 15, 21 to 25, and 31 to 35. Each of the multiple battery pack BMS100 to 300 can acquire the voltage, battery current, and temperature of battery packs 10, 20, and 30. Each of the multiple battery pack BMS100 to 300 can control the charging and discharging current of battery packs 10 to 30 based on the cell voltage and battery current of the multiple battery cells 11 to 15, 21 to 25, and 31 to 35, and can control the cell balancing operation of the multiple battery cells 11 to 15, 21 to 25, and 31 to 35.

[0034] Each of the multiple current sensors 16, 26, and 36 can respectively measure the battery pack current flowing through the corresponding battery packs 10, 20, and 30, and can send current detection signals IS1, IS2, and IS3 indicating the measured battery pack current to the main control circuit 40. In this case, the multiple current sensors 16, 26, and 36 can also transmit the current detection signals IS1, IS2, and IS3 to the multiple battery pack BMS100 to 300.

[0035] The main control circuit 40 can receive information from multiple battery packs BMS 100 to 300, such as the cell voltages of multiple battery cells 11 to 15, 21 to 25, and 31 to 35, and the voltage, current, and temperature of multiple battery packs 10, 20, and 30. The main control circuit 40 can supply power control signals to the multiple battery packs 10, 20, and 30 to supply the power required for vehicle operation, and can supply charging control signals to charge the multiple battery packs 10, 20, and 30. Additionally, the main control circuit 40 can perform controls necessary for the operation of the battery system 1, and can initiate and control protection operations when an abnormal state of the battery system 1 is detected. The main control circuit 40 may include a memory 41, and information necessary for the operation of the battery system 1 can be stored in the memory 41. For example, information necessary for determining whether the pre-charge resistor is abnormal during pre-charge operation can be stored in the memory 41.

[0036] The relay device 50 may include a plurality of precharge resistors 61 to 63, a plurality of precharge switches 71 to 73, a plurality of main switches 81 to 83, and a plurality of capacitors 91 to 93. The relay device 50 controls the switching operation of the plurality of precharge switches 71 to 73 according to a plurality of precharge gating voltages RVG1 to RVG3 received from the main control circuit 40, and controls the switching operation of the plurality of main switches 81 to 83 according to a plurality of gating voltages VG1 to VG3.

[0037] In relay device 50, one terminal of a plurality of pre-charge resistors 61 to 63 and a plurality of main switches 81 to 83 is connected to line 101, and another terminal of the plurality of main switches 81 to 83 is connected to a corresponding configuration in vehicle 2. Another terminal of each of the plurality of pre-charge resistors 61 to 63 is connected to one terminal of a corresponding one of the plurality of pre-charge switches 71 to 73, and another terminal of the plurality of pre-charge switches 71 to 73 is connected to a corresponding configuration in vehicle 2. Another terminal of pre-charge switch 71 and main switch 81 is connected to one of the two input terminals of inverter 201, and another terminal of pre-charge switch 72 and main switch 82 is connected to one of the two input terminals of EPTO 202, and another terminal of pre-charge switch 73 and main switch 83 is connected to one of the two input terminals of high-speed charger 203. Each of a plurality of capacitors 91 to 93 is connected between another terminal of a corresponding one of the plurality of pre-charge switches 71 to 73 and line 102. Each of the multiple voltage sensors 51 to 53 is connected to the two ends of a corresponding one of the multiple capacitors 91 to 93 to measure the voltages VC1, VC2 and VC3 charged into the multiple capacitors 91 to 93, and can send multiple voltage detection signals VS1, VS2 and VS3 to the main control circuit 40.

[0038] Voltage sensor 103 can be connected between line 101 and line 102 to measure the battery voltage VB, which is the voltage at the two terminals of the battery system 1, and can send a voltage detection signal VBS indicating the measured battery voltage VB to the main control circuit 40.

[0039] The pre-charging operation can be an operation that blocks the surge current generated by pre-connecting the battery system 1 and the vehicle 2 through the pre-charging resistor and pre-charging switch before the main switch is turned on. When the resistance increases due to the deterioration of the pre-charging resistor, various problems as mentioned above occur. Therefore, according to the embodiment, the main control circuit 40 detects the deterioration of multiple pre-charging resistors during the pre-charging operation. During the pre-charging operation, the main control circuit 40 can turn on multiple main switches 81 to 83 while they are in the off state and before a predetermined time before the pre-charging operation is completed. Subsequently, the main control circuit 40 can turn on multiple main switches 81 to 83 and then turn off multiple pre-charging switches 71 to 73.

[0040] In the following text, refer to Figure 2 This describes a method for detecting the degradation of a pre-charge resistor during pre-charge operation, according to an embodiment.

[0041] Figure 2 This is a diagram illustrating a method for detecting the degradation of a pre-charge resistor during pre-charge operation according to an embodiment.

[0042] exist Figure 1 During the pre-charge operation, the electrical paths configured by pre-charge resistors 61, 62 and 63, on-state pre-charge switches 71, 72 and 73, and capacitors 91, 92 and 93, respectively, connected between battery system 1 and inverter 201, EPTO 22 and high-speed charger 203 are defined as branches.

[0043] After the pre-charge operation begins, each of the multiple capacitors 91 to 93 can be charged using the battery voltage VB, such that the voltage of each of the multiple capacitors 91 to 93 can rise within a predetermined delay period to converge to the battery voltage VB. At this time, the delay period is determined based on the product (RC) of the resistance value R of the pre-charge resistor and the capacitance C of the capacitor in each branch; this delay period is called the time constant (T). In this embodiment, the elapsed time during the pre-charge operation is divided into units of time constant, and the determination of whether the pre-charge resistor is abnormal is performed in step 3. However, dividing the elapsed time into units of time constant is only one of the various embodiments of the invention, and the invention is not limited thereto. That is, abnormalities in the pre-charge resistor can be detected at appropriate times according to the design. An abnormality in the pre-charge resistor means that the resistance value has increased due to the deterioration of the pre-charge resistor.

[0044] Figure 3 It is a graph showing the voltage fluctuation of one of a plurality of capacitors during pre-charge operation according to an embodiment.

[0045] like Figure 3 As shown, the voltage VC1, which is the voltage across the two terminals of capacitor 91, rises from the start of pre-charging. After a 1T period, VC1 reaches voltage level VC11; after a 4T period, it reaches voltage level VC12; and after a 5T period, it reaches voltage level VC13, which is essentially the same as the battery voltage VB. Other voltages VC2 and VC3 also have similar characteristics. Figure 3 The curve shown in the figure has a similar waveform. However, the time constant T can be different for each pre-charge resistor and capacitor.

[0046] First, the main control circuit 40 receives voltage detection signals VBS and VS1 to VS3 at time 1T, indicating the battery voltage VB and the voltages of multiple capacitors VC1 to VC3, and calculates the branch current (S1). Based on the voltage values ​​indicated by each of the voltage detection signals VBS and VS1 to VS3, the current I1 connected to the first branch of the inverter 201, the current I2 connected to the second branch of the EPTO 22, and the current I3 connected to the third branch of the high-speed charger 203 are calculated. In this case, the main control circuit 40 can use the resistance values ​​of each of the multiple pre-charge resistors 61 to 63 stored in the memory 41. For example, the main control circuit 40 calculates current I1 by dividing the voltage obtained by subtracting the voltage level VC11 of the battery voltage VB from the voltage level VC1 at time 1T by the resistance value of the pre-charge resistor 61 stored in the memory 41, calculates current I2 by dividing the voltage obtained by subtracting the voltage level VC2 of the battery voltage VB at time 1T by the resistance value of the pre-charge resistor 62 stored in the memory 41, and calculates current I3 by dividing the voltage obtained by subtracting the voltage level VC3 of the battery voltage VB at time 1T by the resistance value of the pre-charge resistor 63 stored in the memory 41.

[0047] The main control circuit 40 determines whether the sum of currents I1 to I3 (the sum of branch currents) is the same as the battery current S2. The main control circuit 40 can receive current detection signals IS1 to IS3 from current sensors 16, 26, and 36 of the multiple battery packs 10, 20, and 30, respectively, and calculate the battery current as the current of the battery system 1 by summing the current values ​​indicated by the current detection signals IS1 to IS3. However, the invention is not limited to this, and the current sensor can be located in either line 101 or line 102 to measure the battery current.

[0048] As a result of S2, if the sum of the branch currents is the same as the battery current, the pre-charging operation continues. If the sum of the branch currents is different from the battery current, the main control circuit 40 can determine that at least one of the multiple pre-charging resistors 61 to 63 is defective. That is, when the resistance value increases due to the deterioration of at least one of the multiple pre-charging resistors 61 to 63, at least one of the currents I1 to I3 may differ from the actual branch current. The battery current IB is actually the sum of the multiple branch currents, and the currents I1 to I3 calculated by the main control circuit 40 are based on the resistance values ​​stored in the memory 41. Therefore, due to the deterioration of the pre-charging resistors, there is a difference between the stored resistance and the actual resistance. Due to this difference, the battery current IB is different from the calculated sum of the branch currents (I1+I2+I3). Therefore, it can be confirmed that the main control circuit 40 has a pre-charging resistor whose resistance value has increased due to deterioration among the multiple pre-charging resistors 61 to 63.

[0049] As the pre-charging operation continues, at time 4T, the main control circuit 40 calculates the branch charging slope (S4) using multiple capacitor voltages VC1 to VC3. For example, the main control circuit 40 can calculate the branch charging slope by dividing the value obtained by subtracting the voltage level VC11 of VC1 at time 1T from the voltage level VC12 at time 4T by time 3T. Similarly, the main control circuit 40 can calculate the charging slope of each branch by dividing the value obtained by subtracting the voltage levels of VC2 and VC3 at time 1T from the voltage levels at time 4T by time 3T.

[0050] The main control circuit 40 compares the charging slope of each branch with the reference slope and determines whether the charging slope of each branch is equal to or greater than the reference slope (S5). When the pre-charge resistor is in its normal state, the reference slope can be set as the branch charging slope. Step S5 can be performed for each branch.

[0051] As a result of S5, if the branch charging slope is less than the reference slope, the main control circuit 40 determines that the pre-charging resistor of the corresponding branch is abnormal.

[0052] As determined by S5, if the charging slope of all branches is equal to or greater than the reference slope, the main control circuit 40 continues the pre-charging operation. As the resistance value increases due to the deterioration of the pre-charging resistors, the rising slope of voltages VC1, VC2, and VC3 decreases. Therefore, the main control circuit 40 calculates the charging slope of each branch based on this and compares it with the reference slope, thereby determining that the pre-charging resistors of branches with slopes lower than the reference slope are abnormal due to deterioration.

[0053] As the pre-charging operation continues, the main control circuit 40 measures the charging time (S7) of the branch where the levels of multiple voltages VC1 to VC3 reach the battery voltage VB. For example... Figure 3 As shown, if time 5T has elapsed, the voltage VC1 reaches the battery voltage VB, where time 5T is differentiated based on the resistance value of the pre-charge resistor in each branch.

[0054] The main control circuit 40 compares the charging time of each of the multiple branches with a reference time and determines whether each of the multiple branch charging times is equal to or less than the reference time (S8). If the resistance value increases due to the deterioration of the pre-charge resistor, the actual measured time 5T is longer than the time 5T based on the pre-charge resistor under normal conditions. The reference time can be the time 5T determined by the steady-state pre-charge resistor.

[0055] As determined by S8, when the charging time of multiple branches is longer than the reference time, the main control circuit 40 determines that the pre-charging resistor of the corresponding branch is abnormal (S9).

[0056] As determined by S8, if the charging time of multiple branches is less than or equal to the reference time, the main control circuit 40 determines that all pre-charge resistors are normal (S10).

[0057] Thus, during the pre-charging operation period, the implementation can determine whether the pre-charging resistor is abnormal through three steps. If the pre-charging resistor is determined to be abnormal, the pre-charging operation is stopped, and the main control circuit 40 can notify of the abnormality in the pre-charging resistor through an interface (not shown) provided in at least one of the battery system 1 and the vehicle 2.

[0058] Although the invention has been described in conjunction with what is now considered to be practical embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. Rather, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A battery system comprising: Multiple battery packs, wherein the multiple battery packs are connected in parallel with each other and each includes multiple battery cells; Multiple branches connected in parallel, the multiple branches including: A plurality of pre-charge resistors, wherein one terminal of each of the plurality of pre-charge resistors is connected to one terminal of each of the plurality of battery packs; A plurality of precharge switches, wherein one terminal of each of the plurality of precharge switches is connected to another terminal of each of the plurality of precharge resistors; A plurality of capacitors, wherein one terminal of each of the plurality of capacitors is connected to another terminal of each of the plurality of precharge switches; and The main control circuit, during the first period of the pre-charge operation, determines whether the multiple pre-charge resistors are abnormal by comparing the sum of multiple branch currents calculated using pre-stored values ​​of multiple resistors and the voltage at the two terminals of the multiple pre-charge resistors with the battery current flowing through at least one battery pack. Each of the plurality of pre-charge resistors, each of the plurality of pre-charge switches connected to another terminal of each of the plurality of pre-charge resistors, and each of the plurality of capacitors connected to another terminal of each of the plurality of pre-charge switches are connected in series to form a branch.

2. The battery system according to claim 1, wherein, The main control circuit calculates multiple branch charging slopes based on the difference between the multiple capacitor voltages of multiple capacitors that have passed the second time period during the execution of the pre-charging operation and the multiple capacitor voltages of multiple capacitors that have passed the first time period, and determines that the pre-charging resistor of the branch with a branch charging slope smaller than a predetermined reference slope is abnormal.

3. The battery system according to claim 2, wherein, The reference slope is the branch charging slope when each of the plurality of pre-charge resistors is in a normal state.

4. The battery system according to claim 2, wherein, The first time period is a time constant determined by the resistance value of each of the plurality of pre-charge resistors and the capacitance of each of the plurality of capacitors, and The second time period is a time period corresponding to a predetermined integer multiple of the time constant.

5. The battery system according to claim 2, wherein, The main control circuit measures the charging time of multiple branches when the voltage of each of the multiple capacitors reaches the voltage of at least one battery pack, and determines that the pre-charge resistor of the branch with a charging time longer than a predetermined reference time is abnormal.

6. The battery system according to claim 5, wherein, The reference time is the branch charging time when each of the multiple pre-charge resistors is in normal condition.

7. The battery system according to claim 1, wherein, The first time period is a time period corresponding to a time constant determined by the resistance value of each of the plurality of pre-charge resistors and the capacitance of each of the plurality of capacitors.

8. A method for determining a pre-charge resistor malfunction in a battery system, the battery system comprising multiple battery packs and multiple branches, the multiple battery packs being connected in parallel and each comprising multiple battery cells, the multiple branches being connected in parallel and comprising multiple pre-charge resistors, multiple pre-charge switches, and multiple capacitors, wherein, One terminal of each of the plurality of pre-charge resistors is connected to one terminal of each of the plurality of battery packs, one terminal of each of the plurality of pre-charge switches is connected to another terminal of each of the plurality of pre-charge resistors, and one terminal of each of the plurality of capacitors is connected to another terminal of each of the plurality of pre-charge switches. The method includes the following steps: Multiple branch currents are calculated by using the voltages at the two terminals of multiple pre-charge resistors during the first time period of the pre-charge operation and multiple pre-stored resistance values ​​of the multiple pre-charge resistors. The sum of the currents in the plurality of branches is first compared with the battery current flowing through at least one of the battery packs; and If, as a result of the initial comparison, the sum of the multiple branch currents differs from the battery current, then at least one of the multiple pre-charge resistors is determined to be abnormal. Each of the plurality of pre-charge resistors, each of the plurality of pre-charge switches connected to another terminal of each of the plurality of pre-charge resistors, and each of the plurality of capacitors connected to another terminal of each of the plurality of pre-charge switches are connected in series to form a branch.

9. The method for determining an anomaly in the pre-charge resistor of a battery system according to claim 8, further comprising the following steps: The charging slope of multiple branches is calculated based on the difference between the voltages of multiple capacitors during the second period and the voltages of multiple capacitors during the first period. The second step involves comparing each of the multiple branch charging slopes with a predetermined reference slope. as well as As a result of the second comparison, it was determined that the pre-charge resistor of the branch with a branch charging slope greater than the reference slope was abnormal.

10. The method for determining an anomaly in the pre-charge resistor of a battery system according to claim 9, wherein, The reference slope is the branch charging slope when each of the plurality of pre-charge resistors is in a steady state.

11. The method for determining an anomaly in the pre-charge resistor of a battery system according to claim 9, further comprising the following steps: Measure the charging time of multiple branches, during which the voltage in each of the multiple capacitors charged reaches the voltage of the at least one battery pack. The charging time of the multiple branches is compared with a predetermined reference time for the third time; as well as As a result of the third comparison, it was determined that the pre-charge resistor of the branch with a branch charging time longer than the reference time was abnormal.

12. The method for determining an anomaly in the pre-charge resistor of a battery system according to claim 11, wherein, The reference time is the branch charging time when each of the plurality of pre-charge resistors is in a normal state.

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