Insulation resistance measurement device and battery system

Abstract

This battery system comprises: a first insulation resistance monitoring circuit that provides a first voltage obtained by voltage division using first and second resistors between a ground terminal and a positive electrode of a battery pack connected to a load; a second insulation resistance monitoring circuit that provides a second voltage obtained by voltage division using third and fourth resistors between the ground terminal and a negative electrode of the battery pack; a third insulation resistance monitoring circuit that provides a third voltage obtained by voltage division using fifth and sixth resistors between the ground terminal and a first terminal of the load; a fourth insulation resistance monitoring circuit that provides a fourth voltage obtained by voltage division using seventh and eighth resistors between the ground terminal and a second terminal of the load; and an MCU that diagnoses an insulation state of the load by using the third and fourth voltages and diagnoses an insulation state of the battery pack by using the first and second voltages.

Description

Insulation resistance measuring device and battery system

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

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2025-0013988 dated February 4, 2025, and all contents disclosed in the document of said Korean patent application are incorporated herein as part of this specification.

[0003] This description relates to an insulation resistance measuring device and a battery system.

[0004] Electric vehicles can be driven using electric motors. To drive the electric motors, electric vehicles use battery packs, which are high-voltage power sources. In addition to electric vehicles, battery packs are used in various external devices.

[0005] In external devices using battery packs, it is necessary to maintain proper insulation between the battery pack and the external device. If the insulation of the battery pack is not maintained, leakage current occurs. Leakage current can cause unexpected discharge of the battery pack or malfunction of electrical components in the external device, and can result in fatal electric shock injuries to humans. Therefore, a Battery Management System (BMS) that manages the battery pack includes an insulation resistance measuring device equipped with an insulation diagnostic function.

[0006] Generally, the insulation resistance measurement circuit is provided at the battery pack terminal; in this case, if the relay connecting the battery pack and the external device is open, the insulation resistance of the external device cannot be checked.

[0007] In addition, Y-capacitors may be connected to the electrical components of external devices (e.g., inverters) to eliminate high-frequency noise from the power input from the battery pack. However, in the event of unexpected situations such as sudden power supply, high voltage may be charged into the Y-capacitors. If the voltage charged in the Y-capacitors remains undischarged, the risk of electric shock increases when a user's body comes into contact with the grounding part during maintenance or the use of the external device.

[0008] Some embodiments of the present disclosure aim to provide an insulation resistance measuring device and a battery system capable of measuring the insulation resistance of a load regardless of whether a relay connecting a battery pack and an external device is on or off.

[0009] According to one embodiment, a battery system may be provided. The battery system comprises a battery pack connected to a load of an external device, a first resistor, a first switch, and a second resistor connected in series between the positive terminal of the battery pack and a ground terminal, a first insulation resistance monitoring circuit providing a first voltage divided by the first resistor and the second resistor, a first DC voltage source connected in series between the ground terminal and the negative terminal of the battery pack, a third resistor, a second switch, and a fourth resistor, a second insulation resistance monitoring circuit providing a second voltage divided by the third resistor and the fourth resistor, a first relay located between the positive terminal of the battery pack and a first terminal of the load, a second relay located between the negative terminal of the battery pack and a second terminal of the load, a first capacitor connected between the first terminal of the load and the second terminal of the load, a third resistor, a third switch, and a sixth resistor connected in series between the first terminal of the load and the ground terminal, a third insulation resistance monitoring circuit providing a third voltage divided by the fifth resistor and the sixth resistor, and the ground terminal and the It includes a second DC voltage source connected in series between the second terminals of a load, a seventh resistor, a fourth switch, and an eighth resistor, and a fourth insulation resistance monitoring circuit that provides a fourth voltage divided by the seventh resistor and the eighth resistor, and an MCU (Main Control Unit) that diagnoses the insulation state of the load using the third voltage and the fourth voltage, and diagnoses the insulation state of the battery pack using the first voltage and the second voltage.

[0010] The battery system may further include a second capacitor connected between the first terminal of the load and the ground terminal, and a third capacitor connected between the ground terminal and the second terminal of the load, and the MCU may diagnose the insulation state of the load using the third voltage and the fourth voltage when the first relay and the second relay are in the ON state, and if the insulation state of the load is determined to be symmetric insulation breakdown, the insulation state of the battery pack may be diagnosed using the first voltage and the second voltage, and if the insulation state of the battery pack is determined to be insulation breakdown, the first relay and the second relay may be switched to the OFF state and the third switch and the fourth switch may be turned ON to discharge the second capacitor and the third capacitor.

[0011] The above MCU can measure a first insulation resistance formed between the first terminal of the load and the ground terminal and a second insulation resistance formed between the ground terminal and the second terminal of the load using the third voltage and the fourth voltage, and if both the first insulation resistance and the second insulation resistance are less than a reference value, the insulation state of the load can be determined as the symmetric insulation breakdown.

[0012] When the MCU determines that the insulation state of the load is asymmetric insulation breakdown, it can switch the first relay and the second relay to an off state and turn on the third switch and the fourth switch to discharge the second capacitor and the third capacitor, and can re-diagnose the insulation state of the load using the third voltage and the fourth voltage.

[0013] If the insulation state of the load according to the re-diagnosis is asymmetric insulation breakdown, the MCU can diagnose the insulation state of the battery pack using the first voltage and the second voltage, and can diagnose the final insulation breakdown based on the insulation state of the battery pack.

[0014] The above MCU can determine that the insulation state of the load is the asymmetric insulation breakdown if the first insulation resistance or the second insulation resistance is less than the reference value.

[0015] The MCU can periodically perform the operation of simultaneously turning on the first and third switches and simultaneously turning on the second and fourth switches, thereby periodically receiving the first voltage, the second voltage, the third voltage, and the fourth voltage.

[0016] The MCU can periodically perform an operation of turning on the first switch, the second switch, the third switch, and the fourth switch one by one for a predetermined period, thereby periodically receiving the first voltage, the second voltage, the third voltage, and the fourth voltage.

[0017] According to another embodiment, an insulation resistance measuring device of a battery management system that is connected to a load of an external device and manages a battery pack may be provided. The insulation resistance measuring device comprises: a first monitoring circuit for measuring a first voltage divided by a first resistor and a second resistor connected in series between the positive terminal of the battery pack and a ground terminal, and a second voltage divided by a third resistor and a fourth resistor connected in series between the ground terminal and the negative terminal of the battery pack; a first relay connected between the positive terminal of the battery pack and a positive terminal of the battery pack connected to a first terminal of the load; a second relay connected between the negative terminal of the battery pack and a negative terminal of the battery pack connected to a second terminal of the load; a first capacitor connected between the first terminal of the load and the second terminal of the load; a second monitoring circuit for measuring a third voltage divided by a fifth resistor and a sixth resistor connected in series between the positive terminal of the battery pack and a ground terminal, and a fourth voltage divided by a seventh resistor and an eighth resistor connected in series between the ground terminal and the negative terminal of the battery pack; and, using the first voltage and the second voltage, a first insulation resistance formed between the positive terminal of the battery pack and the ground terminal and the ground terminal and It may include an MCU (Main Control Unit) that measures a second insulation resistance formed between the negative electrodes of the battery pack, and uses the third voltage and the fourth voltage to measure a third insulation resistance formed between the first terminal of the load and the ground terminal and a fourth insulation resistance formed between the ground terminal and the second terminal of the load.

[0018] The first monitoring circuit may further include a first switch connected between the positive terminal of the battery pack and the ground terminal on a path formed by the first resistor and the second resistor, and a first DC voltage source and a second switch connected between the ground terminal and the negative terminal of the battery pack on a path formed by the third resistor and the fourth resistor; the second monitoring circuit may further include a third switch connected between the positive terminal of the battery pack and the ground terminal on a path formed by the fifth resistor and the sixth resistor, and a second DC voltage source and a fourth switch connected between the ground terminal and the negative terminal of the battery pack on a path formed by the seventh resistor and the eighth resistor; and the MCU may diagnose the insulation state of the load based on the third insulation resistance and the fourth insulation resistance when the first relay and the second relay are in the ON state, and if the insulation state of the load is determined to be symmetric insulation breakdown, the insulation state of the battery pack may diagnose the insulation state of the battery pack based on the first insulation resistance and the second insulation resistance. If the insulation state of the battery pack is determined to be insulation breakdown, the first relay and the second relay are switched to the off state, and the third switch and the fourth switch are turned on, thereby discharging the second capacitor connected between the first terminal of the load and the ground terminal, and the third capacitor connected between the ground terminal and the second terminal of the load.

[0019] The MCU can measure the voltage of the battery pack and determine a reference value for diagnosing the insulation state based on the voltage of the battery pack, and if both the third insulation resistance and the fourth insulation resistance are less than the reference value, the insulation state of the load can be determined as the symmetric insulation breakdown.

[0020] When the MCU determines that the insulation state of the load is asymmetric insulation breakdown, it can switch the first relay and the second relay to an off state and turn on the third switch and the fourth switch to discharge the second capacitor and the third capacitor, and can re-diagnose the insulation state of the load using the third voltage and the fourth voltage.

[0021] If the insulation state of the load according to the re-diagnosis is asymmetric insulation breakdown, the MCU can diagnose the insulation state of the battery pack using the first voltage and the second voltage, and can diagnose the final insulation breakdown based on the insulation state of the battery pack.

[0022] The above MCU can determine that the insulation state of the load is the asymmetric insulation breakdown if the first insulation resistance or the second insulation resistance is less than the reference value.

[0023] The MCU can periodically perform the operation of simultaneously turning on the first and third switches and simultaneously turning on the second and fourth switches, thereby periodically receiving the first voltage, the second voltage, the third voltage, and the fourth voltage.

[0024] The MCU can periodically perform an operation of turning on the first switch, the second switch, the third switch, and the fourth switch one by one for a predetermined period, thereby periodically receiving the first voltage, the second voltage, the third voltage, and the fourth voltage.

[0025] According to at least one of the embodiments, the insulation resistance of the load can be measured regardless of whether the relay connecting the battery pack and the external device is on or off.

[0026] In addition, according to at least one of the embodiments, the risk of electric shock during maintenance work can be prevented by discharging the Y-capacitor connected between the load and the ground terminal when the insulation of the load and the battery pack breaks down.

[0027] In addition, according to at least one of the embodiments, the accuracy of the insulation state diagnosis can be improved by discharging the Y-capacitor connected between the load and the ground terminal when the load is asymmetrically broken and re-diagnosing the insulation state of the load.

[0028] FIG. 1 is a drawing showing an example of an external device using a battery system according to one embodiment.

[0029] FIG. 2 is a diagram showing an example of the first to fourth insulation resistance monitoring circuits and voltage monitoring circuits illustrated in FIG. 1.

[0030] FIG. 3 is a diagram showing an example of a switching timing diagram for measuring insulation resistance according to an embodiment.

[0031] FIG. 4 is a diagram illustrating the voltage of the first insulation resistance monitoring terminal when the first switch is turned on while the first relay and the second relay shown in FIG. 2 are turned off.

[0032] FIG. 5 is a diagram illustrating the voltage of the second insulation resistance monitoring terminal when the second switch is turned on while the first relay and the second relay shown in FIG. 2 are turned off.

[0033] FIG. 6 is a diagram illustrating the voltage of the first and third insulation resistance monitoring terminals when the first switch and the third switch are turned on while the first relay and the second relay shown in FIG. 2 are turned on.

[0034] FIG. 7 is a diagram illustrating the voltage of the second and fourth insulation resistance monitoring terminals when the second switch and the fourth switch are turned on while the first relay and the second relay shown in FIG. 2 are turned on.

[0035] FIGS. 8 to 10 are flowcharts illustrating a method for diagnosing an insulation state when a first relay and a second relay are switched from an off state to an on state according to one embodiment.

[0036] FIG. 11 is a flowchart illustrating a method for diagnosing an insulation state when a first relay and a second relay are switched from an ON state to an OFF state according to one embodiment.

[0037] Embodiments of the present invention are described below with reference to the attached drawings so that those skilled in the art can easily implement them. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. Furthermore, in order to clearly explain the present invention in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification are given similar reference numerals. In the flowcharts described with reference to the drawings, the order of operations may be changed, various operations may be merged or certain operations may be divided, and specific operations may not be performed.

[0038] Throughout the specification and claims, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0039] Additionally, expressions written in the singular form may be interpreted as singular or plural unless explicit expressions such as "one" or "singular" are used.

[0040] Additionally, terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but said components are not limited by said terms. Such terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present disclosure, the first component may be named the second component, and similarly, the second component may be named the first component.

[0041] Furthermore, when it is stated that one component is "connected" to another component, this includes not only cases where they are "directly or physically connected," but also cases where they are "indirectly or non-contactually connected" with another component in between, or where they are "electrically connected." On the other hand, when it is stated that one component is "directly connected" to another component, it should be understood that there is no other component present in between.

[0042] FIG. 1 is a drawing showing an example of an external device using a battery system according to one embodiment.

[0043] Referring to FIG. 1, the external device (2) can be driven using the battery system (1).

[0044] The battery system (1) may have a structure that is connected to the load of an external device (2) through a positive terminal (OT+) and a negative terminal (OT-).

[0045] The battery system (1) can be discharged by operating as a power source that supplies power to the load.

[0046] In some embodiments, the external device (2) may be, for example, an electronic device, a means of transport, or an energy storage system (ESS), and the means of transport may be, for example, an electric vehicle, a hybrid vehicle, or a smart mobility vehicle.

[0047] In some embodiments, when the external device (2) is a vehicle, the load may include an inverter (210) and a motor (220).

[0048] The inverter (210) can be connected between the positive terminal (OT+) and the negative terminal (OT-) of the battery system (1), and can convert direct current power supplied from the battery pack (10) of the battery system (1) into alternating current power and supply it to the motor (220).

[0049] Additionally, a capacitor (C1) may be connected between the positive terminal (OT+) and the negative terminal (OT-) of the battery system (1). The capacitor (C1) can remove noise from the DC power output from the battery system (1).

[0050] The motor (220) can be driven using alternating current power from the inverter (210). For example, a three-phase alternating current motor can be used as the electric motor (220). Components within the vehicle that receive discharge power from the battery pack (10), including the inverter (210) and the motor (220), can be collectively referred to as electric loads.

[0051] The battery system (1) may include a battery pack (10), a first relay (20), a second relay (30), and an insulation resistance measuring device (100).

[0052] The battery system (1) includes a battery management system (BMS) that manages the battery pack (10), and an insulation resistance measuring device (100) can be implemented in the BMS. In this case, the BMS can be referred to as the insulation resistance measuring device (100).

[0053] The battery pack (10) may include a plurality of battery cells connected in series. The plurality of battery cells are capable of charging and discharging, and the number of the plurality of battery cells and their connection relationship can be designed according to the voltage and capacity required of the battery pack (10).

[0054] The first relay (20) and the second relay (30) can provide a current path during charging and discharging of the battery pack (10).

[0055] The first relay (20) can be connected between the positive terminal (P+) of the battery pack (10) and the positive connection terminal (OT+) of the battery system (1).

[0056] The second relay (30) can be connected between the negative terminal (P-) of the battery pack (10) and the negative terminal (OT-) of the battery system (1).

[0057] The first relay (20) and the second relay (30) can be turned on and off in response to a control signal from the MCU (Main Control Unit) (160) and can control the connection between the battery pack (10) and the external device (2). When the first relay (20) and the second relay (30) are closed, the positive terminal (P+) of the battery pack (10) can be electrically connected to the positive terminal (OT+) of the battery system (1), and the negative terminal (P-) of the battery pack (10) can be electrically connected to the negative terminal (OT-) of the battery system (1).

[0058] The first relay (20) and the second relay (30) may be mechanical contactors that are turned on and off by the magnetic force of a coil, or semiconductor switches such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor).

[0059] An insulation resistor (RPI1) and a Y-capacitor (CPI1) of the battery system (1) may be formed between the positive terminal (P+) of the battery pack (10) and the ground terminal of the external device (2), and an insulation resistor (RNI1) and a Y-capacitor (CNI1) of the battery system (1) may be formed between the negative terminal (P-) of the battery pack (10) and the ground terminal of the external device (2). The Y-capacitors (CPI1, CNI1) can remove high-frequency noise components of the power input to the battery pack (10).

[0060] Additionally, an insulation resistor (RPI2) and a Y-capacitor (CPI2) of the external device (2) may be formed between the positive terminal (OT+) of the battery system (1) and the ground terminal of the external device (2), and an insulation resistor (RNI2) and a Y-capacitor (CNI2) of the external device (2) may be formed between the negative terminal (OT-) of the battery pack (10) and the ground terminal of the external device (2). The ground terminal of the external device (2) may be, for example, the chassis of a vehicle. The Y-capacitors (CPI2, CNI2) can remove high-frequency noise components of the power input to the external device (2).

[0061] The insulation resistance measuring device (100) can measure the voltage and insulation resistance (RPI1, RNI1, RPI2, RNI2) of the battery pack (10). That is, the insulation resistance measuring device (100) can measure not only the insulation resistance (RPI1, RNI1) of the battery system (1) but also the insulation resistance (RPI2, RNI2) of the external device (2).

[0062] The insulation resistance measuring device (100) may include a first insulation resistance monitoring circuit (110), a second insulation resistance monitoring circuit (120), a third insulation resistance monitoring circuit (130), a fourth insulation resistance monitoring circuit (140), a voltage monitoring circuit (150), and an MCU (160).

[0063] The first insulation resistance monitoring circuit (110) can be connected between the positive terminal (P+) of the battery pack (10) and the ground terminal of the external device (2), and can output a first voltage corresponding to the voltage difference between the positive terminal (P+) of the battery pack (10) and the ground terminal of the external device (2) to the MCU (160). For example, the voltage difference between the positive terminal (P+) of the battery pack (10) and the ground terminal of the external device (2) can be distributed using a plurality of resistors, and the voltage distributed by the plurality of resistors can be used as the first voltage.

[0064] The second insulation resistance monitoring circuit (120) can be connected between the ground terminal of the external device (2) and the negative terminal (P-) of the battery pack (10), and can output a second voltage corresponding to the voltage difference between the ground terminal of the external device (2) and the negative terminal (P-) of the battery pack (10) to the MCU (160). For example, the voltage difference between the ground terminal of the external device (2) and the negative terminal (P-) of the battery pack (10) can be distributed using a plurality of resistors, and the voltage distributed by the plurality of resistors can be used as the second voltage.

[0065] The first insulation resistance monitoring circuit (110) and the second insulation resistance monitoring circuit (120) may be monitoring circuits for measuring the insulation resistance of the battery system (1).

[0066] The third insulation resistance monitoring circuit (130) can be connected between the positive terminal (OT+) of the battery pack (10) and the ground terminal of the external device (2), and can output a third voltage corresponding to the voltage difference between the positive terminal (OT+) of the battery pack (10) and the ground terminal of the external device (2) to the MCU (160). For example, the voltage difference between the positive terminal (OT+) of the battery pack (10) and the ground terminal of the external device (2) can be distributed using a plurality of resistors, and the voltage distributed by the plurality of resistors can be used as the third voltage.

[0067] The fourth insulation resistance monitoring circuit (140) can be connected between the ground terminal of the external device (2) and the negative terminal (OT-) of the battery pack (10), and can output a fourth voltage corresponding to the voltage difference between the ground terminal of the external device (2) and the negative terminal (OT-) of the battery pack (10) to the MCU (160). For example, the voltage difference between the ground terminal of the external device (2) and the negative terminal (OT-) of the battery pack (10) can be distributed using a plurality of resistors, and the voltage distributed by the plurality of resistors can be used as the fourth voltage.

[0068] The third insulation resistance monitoring circuit (130) and the fourth insulation resistance monitoring circuit (140) may be monitoring circuits for measuring the insulation resistance of the inverter (210), that is, the load.

[0069] The voltage monitoring circuit (150) can be connected between the positive terminal (P+) of the battery pack (10) and the negative terminal (P-) of the battery pack (10), and can output the pack voltage of the battery pack (10) corresponding to the voltage difference between the positive terminal (P+) of the battery pack (10) and the negative terminal (P-) of the battery pack (10) to the MCU (160).

[0070] In some embodiments, the first insulation resistance monitoring circuit (110), the second insulation resistance monitoring circuit (120), the third insulation resistance monitoring circuit (130), the fourth insulation resistance monitoring circuit (140), and the voltage monitoring circuit (150) can each convert the corresponding voltage into a digital signal and provide the digital signal of the corresponding voltage to the MCU (160).

[0071] The MCU (160) can measure insulation resistance (RPI1, RNI1, RPI2, RNI2) using the first voltage, second voltage, third voltage, fourth voltage, and pack voltage output from the first insulation resistance monitoring circuit (110), second insulation resistance monitoring circuit (120), third insulation resistance monitoring circuit (130), fourth insulation resistance monitoring circuit (140), and voltage monitoring circuit (150), respectively.

[0072] The MCU (160) can diagnose the insulation status of the load of the battery system (1) and the external device (2) using the measured insulation resistance (RPI1, RNI1, RPI2, RNI2).

[0073] In some embodiments, the MCU (160) can perform the overall functions of the BMS. The MCU (160) can control and manage the overall operation of the battery system (1). For example, the MCU (160) can monitor the overall condition of the battery pack (10) and the battery cells included in the battery pack (10) using the pack voltage of the battery pack (10), the cell voltages of the battery cells within the battery pack (10), and the current of the battery pack (10), control the charging and discharging of the battery pack (10), and perform cell balancing operations. The MCU (160) can control the on / off of the first relay (20) and the second relay (30) to control the charging and discharging of the battery pack (10).

[0074] The MCU (160) can be implemented in hardware using at least one of an ASIC (application specific integrated circuit), DSP (digital signal processor), DSPD (digital signal processing device), PLD (programmable logic device), FPGA (field programmable gate array), microprocessor, AP (Application Processor), CPU (Central Processing Unit), GPU (Graphic Processing Unit), and other electrical units for performing functions.

[0075] FIG. 2 is a diagram showing an example of the first to fourth insulation resistance monitoring circuits and voltage monitoring circuits illustrated in FIG. 1.

[0076] Referring to FIG. 2, the first insulation resistance monitoring circuit (110) may include resistors (R1, R2) and a first switch (SW1). One end of resistor (R1) may be connected to the positive terminal (P+) of the battery pack (10). The first switch (SW1) may be connected between the other end of resistor (R1) and one end of resistor (R2). The other end of resistor (R2) may be connected to the ground terminal of an external device (2). The first switch (SW1) may be turned on or off according to a switch control signal (CS1) of the MCU (160).

[0077] The first insulation resistance monitoring circuit (110) has a first insulation resistance monitoring terminal (TR1) on a path formed by resistors (R1, R2) and a first switch (SW1). The first insulation resistance monitoring terminal (TR1) can be connected to one end of resistor (R2) and can output a first voltage corresponding to the voltage difference between the positive terminal (P+) of the battery pack (10) and the ground terminal of the external device (2).

[0078] In some embodiments, the first insulation resistance monitoring terminal (TR1) may be connected to the other end of the resistor (R1).

[0079] In some embodiments, the order of connection of the resistors (R1, R2) and the first switch (SW1) between the positive terminal (P+) and the ground terminal of the battery pack (10) may be changed. In this case, the node where the voltage divided by the resistors (R1, R2) is output [e.g., the contact of the resistors (R1, R2)] may be set as the first insulation resistance monitoring terminal (TR1).

[0080] The second insulation resistance monitoring circuit (120) may include resistors (R3, R4) and a second switch (SW2). One end of resistor (R3) may be connected to the ground terminal of an external device (2), and the second switch (SW2) may be connected between the other end of resistor (R3) and one end of resistor (R4). The other end of resistor (R4) may be connected to the negative terminal (P-) of the battery pack (10). The second switch (SW2) may be turned on or off according to a switch control signal (CS2) of the MCU (160).

[0081] The second insulation resistance monitoring circuit (120) has a second insulation resistance monitoring terminal (TR2) on a path formed by resistors (R3, R4) and a second switch (SW2). The second insulation resistance monitoring terminal (TR2) can be connected to the other end of resistor (R3) and can output a second voltage corresponding to the voltage difference between the ground terminal of the external device (2) and the negative terminal (P-) of the battery pack (10).

[0082] In some embodiments, the second insulation resistance monitoring terminal (TR2) may be connected to one end of the resistor (R4).

[0083] In some embodiments, the second insulation resistance monitoring circuit (120) may further include a DC voltage source (122) on a path formed by resistors (R3, R4) and a second switch (SW2). Since resistors (R3, R4) are connected between the ground terminal and the negative terminal (P-) of the battery pack (10), the DC voltage source (122) may be provided so that the voltage of the second insulation resistance monitoring terminal (TR2) becomes a positive voltage. The negative terminal of the DC voltage source (122) may be connected to the ground terminal, and the positive terminal of the DC voltage source (122) may be connected to one end of resistor (R3).

[0084] In some embodiments, the order of connection of the DC voltage source (122), resistors (R3, R4), and second switch (SW2) between the ground terminal and the negative terminal (P-) of the battery pack (10) may be changed. In this case, the node where the voltage distributed by the resistors (R3, R4) is output [e.g., the contact of the resistors (R3, R4)] may be set as the second insulation resistance monitoring terminal (TR2).

[0085] The third insulation resistance monitoring circuit (130) may include resistors (R5, R6) and a third switch (SW3). One end of resistor (R5) may be connected to the positive terminal (OT+) of the battery pack (10). The third switch (SW3) may be connected between the other end of resistor (R5) and one end of resistor (R6). The other end of resistor (R6) may be connected to the ground terminal of the external device (2). The third switch (SW3) may be turned on or off according to the switch control signal (CS3) of the MCU (160).

[0086] The third insulation resistance monitoring circuit (130) has a third insulation resistance monitoring terminal (TR3) on a path formed by resistors (R5, R6) and a third switch (SW3). The third insulation resistance monitoring terminal (TR3) can be connected to one end of resistor (R6) and can output a third voltage to the MCU (160) corresponding to the voltage difference between the positive terminal (OT+) of the battery pack (10) and the ground terminal of the external device (2).

[0087] In some embodiments, the third insulation resistance monitoring terminal (TR3) may be connected to the other end of the resistor (R5).

[0088] In some embodiments, the order of connection of the resistors (R5, R6) and the third switch (SW3) between the positive terminal (OT+) and the ground terminal of the battery pack (10) may be changed. In this case, the node where the voltage divided by the resistors (R5, R6) is output [e.g., the contact of the resistors (R5, R6)] may be set as the third insulation resistance monitoring terminal (TR3).

[0089] The fourth insulation resistance monitoring circuit (140) may include resistors (R7, R8) and a fourth switch (SW4). One end of resistor (R7) may be connected to the ground terminal of an external device (2), and the fourth switch (SW4) may be connected between the other end of resistor (R7) and one end of resistor (R8). The other end of resistor (R8) may be connected to the negative terminal (OT-) of the battery pack (10). The fourth switch (SW4) may be turned on or off according to a switch control signal (CS4) of the MCU (160).

[0090] The fourth insulation resistance monitoring circuit (140) has a fourth insulation resistance monitoring terminal (TR4) on a path formed by resistors (R7, R8) and a fourth switch (SW4). The fourth insulation resistance monitoring terminal (TR4) can be connected to the other end of resistor (R7) and can output a fourth voltage to the MCU (160) that corresponds to the voltage difference between the ground terminal of the external device (2) and the negative terminal (OT-) of the battery pack (10).

[0091] In some embodiments, the fourth insulation resistance monitoring terminal (TR4) may be connected to one end of the resistor (R8).

[0092] In some embodiments, the fourth insulation resistance monitoring circuit (140) may further include a DC voltage source (142) on the path formed by resistors (R7, R8) and the fourth switch (SW4). Since resistors (R7, R8) are connected between the ground terminal and the negative terminal (OT-) of the battery pack (10), the DC voltage source (142) may be provided so that the voltage of the fourth insulation resistance monitoring terminal (TR4) becomes a positive voltage. The negative terminal of the DC voltage source (142) may be connected to the ground terminal, and the positive terminal of the DC voltage source (VDC2) may be connected to one end of resistor (R7).

[0093] In some embodiments, the order of connection of the DC voltage source (VDC2), resistors (R7, R8), and the fourth switch (SW4) between the ground terminal and the negative terminal (OT-) of the battery pack (10) may be changed. In this case, the node where the voltage divided by the resistors (R7, R8) is output [e.g., the contact of the resistors (R7, R8)] may be set as the fourth insulation resistance monitoring terminal (TR4).

[0094] The voltage monitoring circuit (150) may include resistors (R9, R10). One end of resistor (R9) may be connected to the positive terminal (P+) of the battery pack (10), the other end of resistor (R9) may be connected to one end of resistor (R10), and the other end of resistor (R10) may be connected to the negative terminal (P-) of the battery pack (10).

[0095] The voltage monitoring circuit (150) has a voltage monitoring terminal (TR5) on a path formed by resistors (R9, R10). The voltage monitoring terminal (TR5) can be connected to the other end of resistor (R9) or one end of resistor (R10) and can output a pack voltage corresponding to the voltage difference between the positive terminal (P+) of the battery pack (10) and the negative terminal (P-) of the battery pack (10).

[0096] In some embodiments, the voltage monitoring circuit (150) can measure the voltage of each of the plurality of battery cells of the battery pack (10) and provide the voltages of the plurality of battery cells to the MCU (160), thereby allowing the MCU (160) to calculate the pack voltage.

[0097] FIG. 3 is a diagram showing an example of a switching timing diagram for measuring insulation resistance according to an embodiment.

[0098] Referring to FIG. 3, the MCU (160) can simultaneously turn on the first switch (SW1) and the third switch (SW3) and simultaneously turn off the second switch (SW2) and the fourth switch (SW4) during a first period. The MCU (160) can simultaneously turn on the second switch (SW2) and the fourth switch (SW4) and simultaneously turn off the first switch (SW1) and the third switch (SW3) during a second period. The MCU (160) can repeat the first period and the second period during the insulation resistance measurement period.

[0099] Alternatively, the MCU (160) may set the first switch (SW1), the second switch (SW2), the third switch (SW3), and the fourth switch (SW4) to the ON state one by one.

[0100] Meanwhile, when measuring insulation resistance, the first relay (20) and the second relay (30) may be in an on state or an off state, and may be switched from an on state to an off state or from an off state to an on state.

[0101] For example, if the external device (2) is a vehicle, when the vehicle's engine is turned on, the first relay (20) and the second relay (30) can be switched from an off state to an on state, and when the vehicle is in motion, the first relay (20) and the second relay (30) can be maintained in an on state, and when the vehicle's engine is turned off, the first relay (20) and the second relay (30) can be switched from an on state to an off state.

[0102] In addition, the MCU (160) can discharge the Y-capacitors (CPI2, CNI2) by setting the first relay (20) and the second relay (30) to the off state and the third switch (SW3) and the fourth switch (SW4) to the on state to measure insulation resistance.

[0103] FIG. 4 is a diagram illustrating the voltage of the first insulation resistance monitoring terminal when the first switch is turned on while the first relay and the second relay shown in FIG. 2 are turned off.

[0104] Referring to FIG. 4, when the first switch (SW1) is turned on, a current path through resistors (R1, R2) can be formed between the positive terminal (P+) of the battery pack (10) and the ground terminal of the external device (2). Also, since the second switch (SW2) is turned off, a current path through resistors (R3, R4) is not formed. In this case, since an insulation resistor (RPI1) and a Y-capacitor (CPI1) are formed between the positive terminal (P+) of the battery pack (10) and the ground terminal of the external device, a circuit is formed in which a set of resistors (R1, R2), an insulation resistor (RPI1), and a Y-capacitor (CPI1) are connected in parallel between the positive terminal (P+) of the battery pack (10) and the ground terminal of the external device (2). In addition, a circuit can be formed in which an insulation resistor (RNI1) and a Y-capacitor (CNI1) are connected in parallel between the ground terminal and the negative terminal (P-) of the battery pack (10).

[0105] In this state, the MCU (160) can receive the voltage (V1) of the first insulation resistance monitoring terminal (TR1).

[0106] In the circuit illustrated in FIG. 4, the current flowing through the resistors (R1, R2) of the first insulation resistance monitoring circuit (110) is I1, the current flowing through the insulation resistance (RPI1) is I2, and the current flowing through the Y-capacitor (CPI1) is I C1 , the current flowing through the Y-capacitor (CNI1) is I C2 Let I3 be the current flowing through the insulation resistance (RNI1), and if Kirchhoff's current law is applied with respect to the node (N) connected to the ground terminal, the relationship in Equation 1 can be established.

[0107]

[0108] For convenience, the current flowing through the Y-capacitor (CPI1) and Y-capacitor (CNI1) is ignored in the following explanation. Accordingly, Equation 1 can be simply expressed as Equation 2.

[0109]

[0110] When the voltage of the first insulation resistance monitoring terminal (TR1) is denoted as V1, V1 can have a relationship as shown in Equation 3.

[0111]

[0112] When a set of resistors (R1, R2) and an insulation resistor (RPI1) are each connected in parallel between the positive terminal (P+) of the battery pack (10) and the ground terminal of the external device (2), the voltage across each of them is the same, so the relationship of Equation 4 can be established.

[0113]

[0114] From mathematical equation 4, I2 can be expressed as mathematical equation 5.

[0115]

[0116] From mathematical formulas 2, 3, and 5, I3 can satisfy the relationship of mathematical formula 6.

[0117]

[0118] Also, the voltage of the battery pack (10) is V pack When saying, V pack The relationship in mathematical formula 7 can be established.

[0119]

[0120] In the relationship of mathematical formula 7, if mathematical formulas 5 and 6 are applied, the voltage (V) of the battery pack (10) pack The relationship between ) and the voltage (V1) of the first insulation resistance monitoring terminal (TR1) can be determined as shown in Equation 8.

[0121]

[0122] In mathematical formulas 3 through 8, R1 is the resistance value of resistor (R1), R2 is the resistance value of resistor (R2), and R P1is the resistance value of the insulation resistance (RPI1), and R N1 is the resistance value of the insulation resistance (RNI1).

[0123] FIG. 5 is a diagram illustrating the voltage of the second insulation resistance monitoring terminal when the second switch is turned on while the first relay and the second relay shown in FIG. 2 are turned off.

[0124] Referring to FIG. 5, when the second switch (SW2) is turned on, a current path through resistors (R3, R4) can be formed between the ground terminal of the external device (2) and the negative terminal (P-) of the battery pack (10). Also, since the first switch (SW1) is turned off, a current path through resistors (R1, R2) is not formed. In this case, since an insulation resistor (RNI1) and a Y-capacitor (CNI1) are formed between the ground terminal of the external device (2) and the negative terminal (P-) of the battery pack (10), a circuit is formed in which a set of resistors (R3, R4), an insulation resistor (RNI1), and a Y-capacitor (CNI1) are connected in parallel between the ground terminal of the external device (2) and the negative terminal (P-) of the battery pack (10). In addition, a circuit can be formed in which an insulation resistor (RPI1) and a Y-capacitor (CPI1) are connected in parallel between the positive terminal (P+) and the ground terminal of the battery pack (10).

[0125] In this state, the MCU (160) can receive the voltage (V2) of the second insulation resistance monitoring terminal (TR2).

[0126] In the circuit illustrated in FIG. 5, the current flowing through the resistors (R3, R4) of the second insulation resistance monitoring circuit (120) is I1, the current flowing through the insulation resistance (RNI1) is I2, and the current flowing through the Y-capacitor (CPI1) is I C1 , the current flowing through the Y-capacitor (CNI1) is I C2 Let I3 be the current flowing through the insulation resistance (RPI1), and if Kirchhoff's current law is applied with respect to the node (N) connected to the ground terminal, the relationship in Equation 9 can be established.

[0127]

[0128] Since the Y-capacitors (CPI1, CNI1, CPI2, CNI2) are discharged before starting the insulation resistance measurement, the circuit part involving the Y-capacitors (CPI1, CNI1) is omitted from the explanation. Accordingly, Equation 9 can be expressed as Equation 10.

[0129]

[0130] When the voltage of the second insulation resistance monitoring terminal (TR2) is denoted as V2 and the voltage supplied by the DC voltage source (122) is denoted as VDC, V2 can have a relationship as shown in Equation 11.

[0131]

[0132] From mathematical equation 11, I1 can satisfy the relationship of mathematical equation 12.

[0133]

[0134] When a DC voltage source (122), a set of resistors (R3, R4), and an insulation resistor (RNI1) are each connected in parallel between the ground terminal of the external device (2) and the negative terminal (P-) of the battery pack (10), the voltage applied to each of them is the same, so the relationship of Equation 13 can be established.

[0135]

[0136] From mathematical equation 13, I2 can be expressed as mathematical equation 14.

[0137]

[0138] From mathematical formulas 10, 12, and 14, I3 can satisfy the relationship of mathematical formula 15.

[0139]

[0140] Also, the voltage of the battery pack (10) is V pack When saying, Vpack The relationship in mathematical formula 16 can be established.

[0141]

[0142] In the relationship of mathematical formula 16, if mathematical formulas 14 and 15 are applied, the voltage (V) of the battery pack (10) pack The relationship between the voltage (V2) of the second insulation resistance monitoring terminal (TR2) and the () can be determined as shown in Equation 17.

[0143]

[0144] In mathematical formulas 11 through 17, R3 is the resistance value of resistor (R3), R4 is the resistance value of resistor (R4), and R P1 is the resistance value of the insulation resistance (RPI1), and R N1 is the resistance value of the insulation resistance (RNI1).

[0145] The MCU (160) is the voltage (V1) of the first insulation resistance monitoring terminal (TR1), the voltage (V2) of the second insulation resistance monitoring terminal (TR2), and the voltage (V) of the battery pack (10). pack The resistance values ​​of the insulation resistances (RPI1, RNI1) can be calculated based on ). The MCU (160) can calculate the resistance values ​​of the insulation resistances (RPI1, RNI1) as in Equations 18 and 19, respectively, based on Equations 8 and 17.

[0146]

[0147]

[0148] In mathematical formulas 18 and 19, A, B, C, and D can be defined as in mathematical formulas 20, 21, 22, and 23, respectively.

[0149]

[0150]

[0151]

[0152]

[0153] Additionally, when the first relay (20) and the second relay (30) are off, and the third switch (SW3) is turned on, the MCU (160) can receive the voltage (V3) of the third insulation resistance monitoring terminal (TR3). The voltage (V) of the battery pack (10) pack Assuming that the capacitor (C1) is charged, a relationship between the voltage charged in the capacitor (C1) and the voltage (V3) of the third insulation resistance monitoring terminal (TR3) can be derived, similar to what is explained based on mathematical formulas 1 through 8. However, since the voltage of the capacitor (C1) is gradually discharged, the first relay (20) and the second relay (30) are turned off, and the voltage (V3) of the third insulation resistance monitoring terminal (TR3) can be used for insulation resistance measurement for a predetermined period of time.

[0154] In addition, when the first relay (20) and the second relay (30) are off and the fourth switch (SW4) is turned on, the voltage supplied by the DC voltage source (142) can be distributed by the resistors (R7, R8), and the MCU (160) can receive the voltage distributed by the resistors (R7, R8) as the voltage (V4) of the fourth insulation resistance monitoring terminal (TR4).

[0155] The MCU (160) can calculate the resistance value of the insulation resistance (RPI2, RNI2) based on the voltage (V3) of the third insulation resistance monitoring terminal (TR3), the voltage (V4) of the fourth insulation resistance monitoring terminal (TR4), and the voltage of the capacitor (C1).

[0156] FIG. 6 is a diagram illustrating the voltage of the first and third insulation resistance monitoring terminals when the first switch and the third switch are turned on while the first relay and the second relay shown in FIG. 2 are turned on.

[0157] Referring to FIG. 6, when the first relay and the second relay are turned on, a current path through resistors (R1, R2) and resistors (R5, R6) can be formed between the positive terminal (P+) of the battery pack (10) and the ground terminal of the external device (2) by turning on the first switch (SW1) and the third switch (SW3). Also, since the second switch (SW2) and the fourth switch (SW4) are turned off, a current path through resistors (R3, R4) and a current path through resistors (R7, R8) are not formed. In this case, since insulation resistors (RPI1, RPI2) are formed between the positive terminal (P+) of the battery pack (10) and the ground terminal of the external device, a circuit is formed in which the set of resistors (R1, R2), insulation resistor (RPI1), and insulation resistor (RPI2) are connected in parallel between the positive terminal (P+) of the battery pack (10) and the ground terminal of the external device (2). In addition, a circuit can be formed in which insulation resistors (RNI1, RNI2) are connected in parallel between the ground terminal and the negative terminal (P-) of the battery pack (10). In FIG. 6, the Y-capacitors (CPI1, CPI2, CNI1, CNI2) are omitted for convenience.

[0158] In this state, the MCU (160) can receive the voltage (V1) of the first insulation resistance monitoring terminal (TR1) and the voltage (V3) of the third insulation resistance monitoring terminal (TR3).

[0159] In the circuit illustrated in FIG. 6, the current flowing through the resistors (R1, R2) of the first insulation resistance monitoring circuit (110) is denoted as I1, the current flowing through the insulation resistance (RPI1) is denoted as I2, the current flowing through the insulation resistance (RNI1) is denoted as I3, the current flowing through the resistors (R5, R6) is denoted as I4, the current flowing through the insulation resistance (RPI2) is denoted as I5, and the current flowing through the insulation resistance (RNI2) is denoted as I6. When Kirchhoff's current law is applied with respect to the node (N) connected to the ground terminal, the relationship of Equation 24 can be established.

[0160]

[0161] When the voltage of the first insulation resistance monitoring terminal (TR1) is denoted as V1, V1 can have a relationship as shown in Equation 25.

[0162]

[0163] In addition, when the voltage of the third insulation resistance monitoring terminal (TR3) is denoted as V3, V3 can have a relationship as shown in Equation 26.

[0164]

[0165] When a set of resistors (R1, R2), a set of resistors (R5, R6), and insulation resistors (RPI1, RPI2) are each connected in parallel between the positive terminal (P+) of the battery pack (10) and the ground terminal of the external device (2), the voltage across each of them is the same, so the relationship of Equation 27 can be established.

[0166]

[0167] From Equation 27, I2 and I5 can be expressed as Equations 28 and 29.

[0168]

[0169]

[0170] In mathematical formulas 25 through 19, R1 is the resistance value of resistor (R1), R2 is the resistance value of resistor (R2), R5 is the resistance value of resistor (R5), and R6 is the resistance value of resistor (R6). Also, R P1 is the resistance value of the insulation resistance (RPI1), and R P2 is the resistance value of the insulation resistance (RPI2).

[0171] When insulation breakdown occurs, current flows through a resistor with a smaller resistance value. Therefore, by calculating the equivalent resistance of the insulation resistances (RNI1, RNI2) and simplifying I3 and I6 into the current I7 flowing through the equivalent resistance, the current I7 can be derived.

[0172] When insulation resistors (RNI1, RNI2) are connected in parallel between the ground terminal of the external device (2) and the negative terminal (P-) of the battery pack (10), if insulation breakdown occurs, the resistance value of the corresponding insulation resistor decreases, and current flows through the resistor with the smaller resistance value. Therefore, by calculating the equivalent resistance of the insulation resistors (RNI1, RNI2) and simplifying I3 and I6 into the current I7 flowing through the equivalent resistance, the current I7 can be derived. By using the current I7 flowing through the equivalent resistance of the insulation resistors (RNI1, RNI2) and the method described above, the voltage (V) of the battery pack (10) pack The relationship between ) and the voltage (V1) of the first insulation resistance monitoring terminal (TR1) and the voltage (V) of the battery pack (10) pack The relationship between the voltage (V3) of the third insulation resistance monitoring terminal (TR3) and the third insulation resistance monitoring terminal (TR3) can be determined.

[0173] FIG. 7 is a diagram illustrating the voltage of the second and fourth insulation resistance monitoring terminals when the second switch and the fourth switch are turned on while the first relay and the second relay shown in FIG. 2 are turned on.

[0174] Referring to FIG. 7, when the first relay and the second relay are turned on, the second switch (SW2) and the fourth switch (SW4) are turned on, thereby forming a current path through resistors (R3, R4) and a current path through resistors (R7, R8) respectively between the ground terminal of the external device (2) and the negative terminal (P-) of the battery pack (10). Additionally, since the first switch (SW1) and the third switch (SW3) are turned off, the current path through resistors (R1, R2) and the current path through resistors (R5, R6) are not formed. In this case, since insulation resistors (RNI1, RNI2) are formed between the ground terminal of the external device (2) and the negative terminal (P-) of the battery pack (10), a circuit is formed in which a set of resistors (R3, R4) and insulation resistors (RNI1, RNI2) are each connected in parallel between the ground terminal of the external device (2) and the negative terminal (P-) of the battery pack (10). Additionally, an insulation resistor (RPI1, RPI2) can be formed in parallel between the positive terminal (P+) of the battery pack (10) and the ground terminal. In FIG. 7, the Y-capacitors (CPI1, CPI2, CNI1, CNI2) are omitted for convenience.

[0175] In this state, the MCU (160) can receive the voltage (V3) of the third insulation resistance monitoring terminal (TR3) and the voltage (V4) of the fourth insulation resistance monitoring terminal (TR4).

[0176] In the circuit illustrated in FIG. 7, the current flowing through the resistors (R3, R4) of the second insulation resistance monitoring circuit (120) is denoted as I1, the current flowing through the insulation resistance (RNI1) is denoted as I2, the current flowing through the insulation resistance (RPI1) is denoted as I3, the current flowing through the resistors (R7, R8) is denoted as I4, the current flowing through the insulation resistance (RNI2) is denoted as I5, and the current flowing through the insulation resistance (RPI2) is denoted as I6. When Kirchhoff's current law is applied with respect to the node (N) connected to the ground terminal, the relationship of Equation 30 can be established.

[0177]

[0178] When the voltage of the second insulation resistance monitoring terminal (TR2) is denoted as V2 and the voltage supplied by the DC voltage source (122) is denoted as VDC, V2 can have a relationship as shown in Equation 31.

[0179]

[0180] From mathematical equation 31, I1 can satisfy the relationship of mathematical equation 32.

[0181]

[0182] In addition, when the voltage of the fourth insulation resistance monitoring terminal (TR4) is denoted as V4, V4 can have a relationship as shown in Equation 33.

[0183]

[0184] From mathematical equation 33, I4 can satisfy the relationship of mathematical equation 34.

[0185]

[0186] Next, when a set of DC voltage sources (122) and resistors (R3, R4), a set of DC voltage sources (142) and resistors (R7, R8), and insulation resistors (RNI1, RNI2) are each connected in parallel between the ground terminal of the external device (2) and the negative terminal (P-) of the battery pack (10), the voltage applied to each of these is the same, so the relationship of Equation 35 can be established.

[0187]

[0188] From mathematical formula 25, I2 and I5 can be expressed as mathematical formulas 36 and 37.

[0189]

[0190]

[0191] In mathematical formulas 31 through 37, R3 is the resistance value of resistor (R3), R4 is the resistance value of resistor (R4), R7 is the resistance value of resistor (R7), and R8 is the resistance value of resistor (R8). Also, R N1 is the resistance value of the insulation resistance (RNI1), and R N2 is the resistance value of the insulation resistance (RNI2).

[0192] When insulation resistors (RPI1, RPI2) are each connected in parallel between the positive terminal (P+) and the ground terminal of the battery pack (10), if insulation breakdown occurs, the resistance value of the corresponding insulation resistor decreases, and current flows through the resistor with the smaller resistance value. Therefore, by calculating the equivalent resistance of the insulation resistors (RPI1, RPI2) and simplifying I3 and I6 into the current I7 flowing through the equivalent resistance, the current I7 can be derived. By using the current I7 flowing through the equivalent resistance of the insulation resistors (RPI1, RPI2) and the method described above, the voltage (V) of the battery pack (10) pack The relationship between ) and the voltage (V2) of the second insulation resistance monitoring terminal (TR2) and the voltage (V) of the battery pack (10) pack The relationship between ) and the voltage (V4) of the fourth insulation resistance monitoring terminal (TR4) can be determined.

[0193] When the first relay (20) and the second relay (30) are turned on, the MCU (160) can calculate the resistance value of the insulation resistance (RPI2, RNI2) based on the voltage (V3) of the third insulation resistance monitoring terminal (TR3), the voltage (V4) of the fourth insulation resistance monitoring terminal (TR4), and the voltage of the capacitor (C1).

[0194] In addition, when the first relay (20) and the second relay (30) are turned on, the MCU (160) [tests] the voltage (V1) of the first insulation resistance monitoring terminal (TR1), the voltage (V2) of the second insulation resistance monitoring terminal (TR2), and the voltage (V) of the battery pack (10). packThe resistance value of insulation resistance (RPI1, RNI1) can be calculated based on ).

[0195] Next, a method for diagnosing the insulation status of the battery system (1) and the external device (2) based on the on / off status of the first relay (20) and the second relay (30) in the MCU (160) is described.

[0196] FIGS. 8 to 10 are flowcharts illustrating a method for diagnosing an insulation state when a first relay and a second relay are switched from an off state to an on state according to one embodiment.

[0197] Referring to FIG. 8, when power is applied to the external device (2), the MCU (160) can turn off the first relay (20) and the second relay (30) and turn on the third switch (SW3) and the fourth switch (SW4) to discharge the Y-capacitors (CPI2, CNI2) connected to the inverter (210) (S802).

[0198] The MCU (160) measures the voltage of the battery pack (10) (S804) and can set a reference value for diagnosing the insulation state according to the voltage of the battery pack (10) (S806). That is, the reference value for diagnosing the insulation state can be set differently depending on the voltage of the battery pack (10).

[0199] Next, the MCU (160) can receive the voltage (V1) of the first insulation resistance monitoring terminal (TR1), the voltage (V2) of the second insulation resistance monitoring terminal (TR1), the voltage (V3) of the third insulation resistance monitoring terminal (TR3), and the voltage (V4) of the fourth insulation resistance monitoring terminal (TR3) at a set period for measuring insulation resistance (S808).

[0200] In some embodiments, the MCU (160) can turn on the first and third switches (SW1, SW3) as shown in FIG. 3 to simultaneously receive the voltage (V1) of the first insulation resistance monitoring terminal (TR1) and the voltage (V3) of the third insulation resistance monitoring terminal (TR3), and turn on the second and fourth switches (SW2, SW4) to simultaneously receive the voltage (V2) of the second insulation resistance monitoring terminal (TR2) and the voltage (V4) of the fourth insulation resistance monitoring terminal (TR4).

[0201] In some embodiments, the MCU (160) can turn on the first to fourth switches (SW1 to SW4) one by one in sequence to sequentially receive the voltage (V1) of the first insulation resistance monitoring terminal (TR1), the voltage (V2) of the second insulation resistance monitoring terminal (TR1), the voltage (V3) of the third insulation resistance monitoring terminal (TR3), and the voltage (V4) of the fourth insulation resistance monitoring terminal (TR3).

[0202] In some embodiments, when the first relay (20) and the second relay (30) are in the off state, the MCU (160) can receive the voltage (V1) of the first insulation resistance monitoring terminal (TR1), the voltage (V2) of the second insulation resistance monitoring terminal (TR1), and the voltage (V4) of the fourth insulation resistance monitoring terminal (TR3). When the first relay (20) and the second relay (30) are in the on state and then turn off state, the MCU (160) can receive the voltage (V3) of the third insulation resistance monitoring terminal (TR3) for a predetermined time.

[0203] In some embodiments, when the first relay (20) and the second relay (30) are turned on, the MCU (160) can receive the voltage (V1) of the first insulation resistance monitoring terminal (TR1), the voltage (V2) of the second insulation resistance monitoring terminal (TR1), the voltage (V3) of the third insulation resistance monitoring terminal (TR3), and the voltage (V4) of the fourth insulation resistance monitoring terminal (TR3).

[0204] The MCU (160) can diagnose the insulation status of the battery pack (10) and the insulation status of the inverter (210) using the voltage (V1) of the first insulation resistance monitoring terminal (TR1), the voltage (V2) of the second insulation resistance monitoring terminal (TR1), the voltage (V3) of the third insulation resistance monitoring terminal (TR3), and the voltage (V4) of the fourth insulation resistance monitoring terminal (TR3).

[0205] When the first relay (20) and the second relay (30) are off, the MCU (160) can calculate the resistance value of the insulation resistance (RPI1, RNI1) using the voltage (V1) of the first insulation resistance monitoring terminal (TR1), the voltage (V2) of the second insulation resistance monitoring terminal (TR1), and the pack voltage (S812), and can diagnose the insulation state between the positive terminal (P+) of the battery pack (10) and the ground terminal and the insulation state between the ground terminal and the negative terminal (P-) of the battery pack (10) using the resistance value of the insulation resistance (RPI1, RNI1) (S814).

[0206] Meanwhile, when the first relay (20) and the second relay (30) are switched from the off state to the on state (S810), the MCU (160) checks the voltage (V3) of the third insulation resistance monitoring terminal (TR3), the voltage (V4) of the fourth insulation resistance monitoring terminal (TR4), and the pack voltage (V pack The resistance value of the insulation resistance (RPI2, RNI2) can be calculated using the insulation resistance (RPI2, RNI2) (S816), and the insulation state between the first terminal of the inverter (210) connected to the positive terminal (OT+) of the battery system (1) and the ground terminal, and the insulation state between the second terminal of the inverter (210) connected to the negative terminal (OT-) of the battery system (1) and the ground terminal can be diagnosed using the resistance value of the insulation resistance (RPI2, RNI2).

[0207] The MCU (160) can diagnose that the insulation state of the inverter (210) is insulation breakdown if the resistance value of the insulation resistance (RPI2) is less than the reference value or if the resistance value of the insulation resistance (RNI2) is less than the reference value (S818).

[0208] If the MCU (160) determines that the insulation resistance (RPI2) is less than the reference value and that the insulation resistance (RPI2) is less than the reference value, the insulation state between the first terminal of the inverter (210) connected to the positive terminal (OT+) of the battery system (1) and the ground terminal, and the insulation state between the second terminal of the inverter (210) connected to the negative terminal (OT-) of the battery system (1) and the ground terminal are both insulation breakdowns. In this case, the insulation state of the inverter (210) may be a symmetric insulation breakdown.

[0209] If the MCU (160) has a resistance value of insulation resistance (RPI2) that is less than a reference value and a resistance value of insulation resistance (RPI2) that is greater than or equal to a reference value, the insulation state between the first terminal of the inverter (210) and the ground terminal may be insulation breakdown. In this case, the insulation state of the inverter (210) may be asymmetric insulation breakdown.

[0210] If the MCU (160) has a resistance value of insulation resistance (RPI2) greater than or equal to a reference value and a resistance value of insulation resistance (RPI2) less than the reference value, the insulation state between the second terminal of the inverter (210) and the ground terminal may be insulation breakdown. In this case, the insulation state of the inverter (210) may be asymmetric insulation breakdown.

[0211] If the insulation state of the inverter (210) is symmetric insulation breakdown, the MCU (160) can calculate the resistance value of the insulation resistance (RPI1, RNI1) using the voltage (V1) of the first insulation resistance monitoring terminal (TR1), the voltage (V2) of the second insulation resistance monitoring terminal (TR1), and the pack voltage (S822), and can diagnose the insulation state between the positive terminal (P+) of the battery pack (10) and the ground terminal and the insulation state between the ground terminal and the negative terminal (P-) of the battery pack (10) using the resistance value of the insulation resistance (RPI1, RNI1).

[0212] Referring to FIG. 9, the MCU (160) can diagnose that the insulation state of the battery pack (10) is insulation breakdown if the resistance value of the insulation resistance (RPI1) is less than the reference value or if the resistance value of the insulation resistance (RNI1) is less than the reference value (S902).

[0213] The MCU (160) can output a final insulation state diagnosis result if the insulation state of the inverter (210) is symmetric insulation breakdown and the insulation state between the positive terminal (P+) of the battery pack (10) and the ground terminal, or the insulation state between the ground terminal and the negative terminal (P-) of the battery pack (10), is insulation breakdown (S904). The MCU (160) can output insulation breakdown as a final insulation state diagnosis result if the insulation state of the inverter (210) is symmetric insulation breakdown and the insulation state between the positive terminal (P+) of the battery pack (10) and the ground terminal, or the insulation state between the ground terminal and the negative terminal (P-) of the battery pack (10), is insulation breakdown.

[0214] Next, the MCU (160) can set the first relay (20) and the second relay (30) to the off state and the third switch (SW3) and the fourth switch (SW4) to the on state to discharge the Y-capacitors (CPI2, CNI2) connected to the inverter (210) (S906).

[0215] In this way, if the MCU (160) determines that the insulation state of the inverter (210) is symmetric insulation breakdown and the insulation state of the battery pack (10) is insulation breakdown, it can discharge the Y-capacitors (CPI2, CNI2) connected to the inverter (210) for safety (S906).

[0216] The MCU (160) can indicate that the first relay (20) and the second relay (30) will be set to the off state by outputting an insulation state diagnosis result before discharging the Y-capacitors (CPI2, CNI2).

[0217] Again, looking at FIG. 8, in step (S820), if the insulation state of the inverter (210) is asymmetric insulation breakdown, the MCU (160) can output an asymmetric insulation breakdown result (S824).

[0218] The MCU (160) can indicate that the first relay (20) and the second relay (30) will be set to the off state by outputting an asymmetric insulation breakdown result.

[0219] In some embodiments, if the external device (2) is a hybrid vehicle using two or more power sources, when the external device (2) receives an asymmetric insulation breakdown result, it can switch the power source from the battery system to another power source, such as an engine.

[0220] In some embodiments, when the external device (2) is a vehicle that uses only the battery system (1) as a power source, the external device (2) may stop driving when it receives an asymmetric insulation breakdown result.

[0221] Next, after the MCU (160) outputs the asymmetric insulation breakdown result, when the first relay (20) and the second relay (30) are turned off, the Y-capacitors (CPI2, CNI2) connected to the inverter (210) are discharged (S826), and the insulation status of the inverter (210) can be diagnosed again.

[0222] That is, if asymmetric insulation breakdown is diagnosed, the insulation status of the inverter (210) can be re-diagnosed after discharging the Y-capacitors (CPI2, CNI2) to confirm whether the asymmetric insulation breakdown is due to a misdiagnosis.

[0223] Referring to FIG. 10, after the discharge of the Y-capacitors (CPI2, CNI2), the MCU (160) [monitors] the voltage (V3) of the third insulation resistance monitoring terminal (TR3), the voltage (V4) of the fourth insulation resistance monitoring terminal (TR4), and the pack voltage (V pack The resistance value of insulation resistance (RPI2, RNI2) can be calculated using ) (S1010).

[0224] The MCU (160) can determine whether the insulation state of the inverter (210) is still asymmetric insulation breakdown if the resistance value of the insulation resistance (RPI2) is less than the reference value or if the resistance value of the insulation resistance (RNI2) is less than the reference value (S1020).

[0225] If the MCU (160) determines that the insulation state of the inverter (210) is still asymmetric insulation breakdown (S1030), it can calculate the resistance value of the insulation resistance (RPI1, RNI1) using the voltage (V1) of the first insulation resistance monitoring terminal (TR1), the voltage (V2) of the second insulation resistance monitoring terminal (TR1), and the pack voltage (S1040), and can diagnose the insulation state between the positive terminal (P+) of the battery pack (10) and the ground terminal and the insulation state between the ground terminal and the negative terminal (P-) of the battery pack (10) by comparing the resistance value of the insulation resistance (RPI1, RNI1) with a reference value.

[0226] The MCU (160) can determine that the insulation state of the battery pack (10) is insulation breakdown if the resistance value of the insulation resistance (RPI1) is less than the reference value or if the resistance value of the insulation resistance (RNI1) is less than the reference value (S1050).

[0227] The MCU (160) can finally output an insulation state diagnosis result (S1060). The MCU (160) can output insulation breakdown of the inverter (210) and insulation breakdown of the battery pack (10) as an insulation state diagnosis result.

[0228] Meanwhile, while the first relay (20) and the second relay (30) are kept in the ON state, the MCU (160) can repeat steps (S816~S826, S902~S906, S1010~S1060) using the voltage (V1) of the first insulation resistance monitoring terminal (TR1), the voltage (V2) of the second insulation resistance monitoring terminal (TR1), the voltage (V3) of the third insulation resistance monitoring terminal (TR3), and the voltage (V4) of the fourth insulation resistance monitoring terminal (TR3) received from the first to fourth insulation resistance monitoring circuits (110~140).

[0229] FIG. 11 is a flowchart illustrating a method for diagnosing an insulation state when a first relay and a second relay are switched from an ON state to an OFF state according to one embodiment.

[0230] Referring to FIG. 11, when the first relay (20) and the second relay (30) are switched to the off state (S1110), the MCU (160) determines whether the first relay (20) and the second relay (30) have been switched to the off state and whether a predetermined time has elapsed (S1120).

[0231] The MCU (160) can receive the voltage (V3) of the third insulation resistance monitoring terminal (TR3) for a predetermined time after the first relay (20) and the second relay (30) are switched to the off state.

[0232] The MCU (160) can diagnose the insulation state by using the voltage (V3) of the third insulation resistance monitoring terminal (TR3), the voltage (V4) of the fourth insulation resistance monitoring terminal (TR4), and the voltage charged in the capacitor (C1) for a predetermined time when the first relay (20) and the second relay (30) are switched to the off state (S1130).

[0233] The voltage (V3) of the third insulation resistance monitoring terminal (TR3), the voltage (V4) of the fourth insulation resistance monitoring terminal (TR4), and the pack voltage (V pack The step (S1130) of diagnosing the insulation state using ) may include the steps (S816~S826, S902~S906, S1010~S1060) described in FIGS. 8 to 10.

[0234] When the first relay (20) and the second relay (30) are switched to the off state and a predetermined time has elapsed, the MCU (160) checks the voltage (V1) of the first insulation resistance monitoring terminal (TR1), the voltage (V2) of the second insulation resistance monitoring terminal (TR2), and the pack voltage (V pack Using ), the insulation condition between the positive terminal (P+) of the battery pack (10) and the ground terminal, and the insulation condition between the ground terminal and the negative terminal (P-) of the battery pack (10) can be diagnosed (S1140).

[0235] The voltage (V1) of the first insulation resistance monitoring terminal (TR1), the voltage (V2) of the second insulation resistance monitoring terminal (TR2), and the pack voltage (V pack The step (S1140) of diagnosing the insulation state between the positive terminal (P+) of the battery pack (10) and the ground terminal and the insulation state between the ground terminal and the negative terminal (P-) of the battery pack (10) using ) may include the steps (S812, S814) of FIG. 8.

[0236] Although embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims also fall within the scope of the present invention.

Claims

1. A battery pack connected to a load of an external device, A first insulation resistance monitoring circuit comprising a first resistor, a first switch, and a second resistor connected in series between the positive terminal and the ground terminal of the battery pack, and providing a first voltage divided by the first resistor and the second resistor. A second insulation resistance monitoring circuit comprising a first DC voltage source connected in series between the ground terminal and the negative electrode of the battery pack, a third resistor, a second switch, and a fourth resistor, and providing a second voltage divided by the third resistor and the fourth resistor. A first relay located between the positive terminal of the battery pack and the first terminal of the load, A second relay located between the negative electrode of the battery pack and the second terminal of the load, A first capacitor connected between the first terminal of the load and the second terminal of the load, A third insulation resistance monitoring circuit comprising a fifth resistor, a third switch, and a sixth resistor connected in series between the first terminal of the load and the ground terminal, and providing a third voltage divided by the fifth resistor and the sixth resistor. A fourth insulation resistance monitoring circuit comprising a second DC voltage source connected in series between the ground terminal and the second terminal of the load, a seventh resistor, a fourth switch, and an eighth resistor, and providing a fourth voltage divided by the seventh resistor and the eighth resistor, and An MCU (Main Control Unit) that diagnoses the insulation status of the load using the third voltage and the fourth voltage, and diagnoses the insulation status of the battery pack using the first voltage and the second voltage. A battery system including 2. In Paragraph 1, A second capacitor connected between the first terminal of the load and the ground terminal, and A third capacitor connected between the ground terminal and the second terminal of the load. Includes more, The MCU diagnoses the insulation state of the load using the third voltage and the fourth voltage while the first relay and the second relay are in the ON state, and if the insulation state of the load is determined to be symmetrical insulation breakdown, it diagnoses the insulation state of the battery pack using the first voltage and the second voltage, and if the insulation state of the battery pack is determined to be insulation breakdown, it switches the first relay and the second relay to the OFF state and turns on the third switch and the fourth switch to discharge the second capacitor and the third capacitor. Battery system.

3. In Paragraph 2, The MCU measures a first insulation resistance formed between the first terminal of the load and the ground terminal and a second insulation resistance formed between the ground terminal and the second terminal of the load using the third voltage and the fourth voltage, and if both the first insulation resistance and the second insulation resistance are less than a reference value, determines the insulation state of the load as the symmetric insulation breakdown. Battery system.

4. In Paragraph 3, The above MCU, when it determines that the insulation state of the load is asymmetric insulation breakdown, switches the first relay and the second relay to an off state and turns on the third switch and the fourth switch to discharge the second capacitor and the third capacitor, and re-diagnoses the insulation state of the load using the third voltage and the fourth voltage. Battery system.

5. In Paragraph 4, The above MCU diagnoses the insulation state of the battery pack using the first voltage and the second voltage if the insulation state of the load according to the re-diagnosis is asymmetric insulation breakdown, and diagnoses the final insulation breakdown based on the insulation state of the battery pack. Battery system.

6. In Paragraph 4, The above MCU determines that the insulation state of the load is the asymmetric insulation breakdown if the first insulation resistance or the second insulation resistance is less than the reference value. Battery system.

7. In Paragraph 1, The MCU periodically performs the operation of simultaneously turning on the first and third switches and simultaneously turning on the second and fourth switches, thereby periodically receiving the first voltage, the second voltage, the third voltage, and the fourth voltage. Battery system.

8. In Paragraph 1, The MCU periodically performs the operation of turning on the first switch, the second switch, the third switch, and the fourth switch one by one for a predetermined period, thereby periodically receiving the first voltage, the second voltage, the third voltage, and the fourth voltage. Battery system.

9. An insulation resistance measuring device of a battery management system that is connected to a load of an external device and manages a battery pack, A first monitoring circuit for measuring a first voltage divided by a first resistor and a second resistor connected in series between the positive terminal and the ground terminal of the battery pack, and a second voltage divided by a third resistor and a fourth resistor connected in series between the ground terminal and the negative terminal of the battery pack, A first relay connected between the positive terminal of the battery pack and the positive terminal of the battery pack connected to the first terminal of the load, A second relay connected between the negative terminal of the battery pack and the negative terminal of the battery pack connected to the second terminal of the load, A first capacitor connected between the first terminal of the load and the second terminal of the load, A second monitoring circuit for measuring a third voltage divided by a fifth resistor and a sixth resistor connected in series between the positive terminal of the battery pack and the ground terminal, and a fourth voltage divided by a seventh resistor and an eighth resistor connected in series between the ground terminal and the negative terminal of the battery pack, and An MCU (Main Control Unit) that measures a first insulation resistance formed between the positive terminal of the battery pack and the ground terminal and a second insulation resistance formed between the ground terminal and the negative terminal of the battery pack using the first voltage and the second voltage, and measures a third insulation resistance formed between the first terminal of the load and the ground terminal and a fourth insulation resistance formed between the ground terminal and the second terminal of the load using the third voltage and the fourth voltage. An insulation resistance measuring device including 10. In Paragraph 9, The above-mentioned first monitoring circuit is, A first switch connected between the positive terminal of the battery pack and the ground terminal on a path formed by the first resistor and the second resistor, and It further includes a first DC voltage source and a second switch connected between the ground terminal and the negative electrode of the battery pack on a path formed by the third resistor and the fourth resistor, The above second monitoring circuit is, A third switch connected between the positive terminal of the battery pack and the ground terminal on the path formed by the fifth resistor and the sixth resistor, and It further includes a second DC voltage source and a fourth switch connected between the ground terminal and the negative terminal of the battery pack on the path formed by the seventh resistor and the eighth resistor, The MCU diagnoses the insulation state of the load based on the third insulation resistance and the fourth insulation resistance when the first relay and the second relay are in the ON state, and if the insulation state of the load is determined to be symmetric insulation breakdown, diagnoses the insulation state of the battery pack based on the first insulation resistance and the second insulation resistance, and if the insulation state of the battery pack is determined to be insulation breakdown, switches the first relay and the second relay to the OFF state and turns on the third switch and the fourth switch to discharge the second capacitor connected between the first terminal of the load and the ground terminal and the third capacitor connected between the ground terminal and the second terminal of the load. Insulation resistance measuring device.

11. In Paragraph 10, The MCU measures the voltage of the battery pack and determines a reference value for diagnosing the insulation state based on the voltage of the battery pack, and if both the third insulation resistance and the fourth insulation resistance are below the reference value, determines the insulation state of the load as the symmetric insulation breakdown. Insulation resistance measuring device.

12. In Paragraph 11, The above MCU, when it determines that the insulation state of the load is asymmetric insulation breakdown, switches the first relay and the second relay to an off state and turns on the third switch and the fourth switch to discharge the second capacitor and the third capacitor, and re-diagnoses the insulation state of the load using the third voltage and the fourth voltage. Insulation resistance measuring device.

13. In Paragraph 12, The above MCU diagnoses the insulation state of the battery pack using the first voltage and the second voltage if the insulation state of the load according to the re-diagnosis is asymmetric insulation breakdown, and diagnoses the final insulation breakdown based on the insulation state of the battery pack. Insulation resistance measuring device.

14. In Paragraph 13, The above MCU determines that the insulation state of the load is the asymmetric insulation breakdown if the first insulation resistance or the second insulation resistance is less than the reference value. Insulation resistance measuring device.

15. In Paragraph 10, The MCU periodically performs the operation of simultaneously turning on the first and third switches and simultaneously turning on the second and fourth switches, thereby periodically receiving the first voltage, the second voltage, the third voltage, and the fourth voltage. Insulation resistance measuring device.

16. In Paragraph 10, The above MCU is, Periodically performing the operation of turning on the first switch, the second switch, the third switch, and the fourth switch one by one for a predetermined period, thereby periodically receiving the first voltage, the second voltage, the third voltage, and the fourth voltage, Insulation resistance measuring device.

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