Relay fusion diagnostic circuit and relay fusion diagnostic method

Abstract

The battery system includes a battery pack, a first main relay having one end connected to a positive terminal of the battery pack and a second main relay having one end connected to a negative terminal of the battery pack, a first control relay connected between the first main relay and a positive terminal of an inverter and a second control relay connected between the second main relay and a negative terminal of the inverter, a fusion diagnosis circuit including a first resistor and a first photocoupler connected between the positive terminal of the battery pack and the negative terminal of the inverter, and a second resistor and a second photocoupler connected between the negative terminal of the inverter and the negative terminal of the battery pack, and a BMS (Battery Management System) that drives the first and second photocouplers to diagnose fusion of the second control relay.

Description

Technical Field

[0001] 《Cross - References to Related Applications (etc.)》 This application claims the benefit of priority based on Korean Patent Application No. 10 - 2021 - 0170980 filed on December 2, 2021, and all the contents disclosed in the document of the Korean patent application are incorporated herein by reference.

[0002] This disclosure relates to a relay welding diagnosis circuit and a relay welding diagnosis method.

Background Art

[0003] A battery system may include a positive terminal side relay and a negative terminal side relay of the battery. When at least one of the positive terminal side relay and the negative terminal side relay is welded, it may affect battery performance such as reducing the reliability of the battery system. Therefore, it is necessary to diagnose whether the relay included in the battery system is welded.

[0004] In particular, the negative terminal side relay can be connected to the ground level, and it is difficult to diagnose the welding of the relay.

Summary of the Invention

Problems to be Solved by the Invention

[0005] Provided are a relay welding diagnosis circuit and a relay welding diagnosis method capable of diagnosing which relay is welded among a plurality of relays connected to a battery pack by measuring the battery pack voltage in a battery system including the battery pack.

Means for Solving the Problems

[0006] A battery system according to one embodiment of the invention includes a battery pack, a first main relay with one end connected to the positive terminal of the battery pack and a second main relay with one end connected to the negative terminal of the battery pack, a first control relay connected between the first main relay and the positive terminal of an inverter and a second control relay connected between the second main relay and the negative terminal of an inverter, a fusion diagnosis circuit including a first resistor and a first photocoupler connected between the positive terminal of the battery pack and the negative terminal of the inverter, and a second resistor and a second photocoupler connected between the negative terminal of the inverter and the negative terminal of the battery pack, and a BMS (Battery Management System) that drives the first and second photocouplers to diagnose the fusion of the second control relay.

[0007] The BMS transmits a first control signal to drive the first photocoupler and a second control signal to drive the second photocoupler to the fusion splicing diagnostic circuit when the second control relay is open. When the first and second photocouplers are driven by the first and second control signals, the BMS can receive a first voltage signal corresponding to the negative terminal of the inverter.

[0008] The BMS can derive a corresponding first voltage difference between the negative terminal of the inverter and the negative terminal of the battery pack based on the first voltage signal.

[0009] The BMS can diagnose that the second control relay is not fused if the first voltage difference is a voltage corresponding to the battery pack voltage between the positive terminal and the negative terminal of the battery pack.

[0010] The BMS can diagnose that the second control relay is fused if the first voltage difference is a predetermined offset voltage that is different from the voltage that follows the battery pack voltage between the positive terminal and the negative terminal of the battery pack.

[0011] The fusion diagnosis circuit further includes a third resistor and a third photocoupler connected between the positive terminal of the inverter and the negative terminal of the battery pack, and the BMS can drive the third photocoupler to diagnose the fusion of the first control relay.

[0012] The BMS transmits a third control signal to the fusion splicing diagnostic circuit to drive the third photocoupler when the first control relay is open. When the third photocoupler is driven by the third control signal, the BMS can receive a second voltage signal corresponding to the positive terminal of the inverter.

[0013] The BMS can derive a corresponding second voltage difference between the positive terminal of the inverter and the negative terminal of the battery pack based on the second voltage signal.

[0014] The BMS can diagnose that the first control relay is fused if the second voltage difference is a voltage corresponding to the battery pack voltage between the positive terminal and the negative terminal of the battery pack.

[0015] The BMS can diagnose that the first control relay is not fused if the second voltage difference is a predetermined offset voltage that is different from the voltage that corresponds to the battery pack voltage between the positive terminal and the negative terminal of the battery pack.

[0016] A relay fusion diagnosis method according to another embodiment of the invention includes the steps of: the BMS deriving a battery pack voltage corresponding to the voltage between the positive and negative terminals of the battery pack based on the voltage of the positive terminal of the battery pack; connecting the positive terminal of the battery pack and the negative terminal of the inverter via a first resistor; connecting the negative terminal of the inverter and the negative terminal of the battery pack via a second resistor; and if the voltage between the negative terminal of the inverter and the negative terminal of the battery is a voltage corresponding to the battery pack voltage, the BMS diagnoses that the first control relay connected between the negative terminal of the battery pack and the negative terminal of the inverter is not fused.

[0017] The BMS may further include the step of diagnosing that the first control relay is fused if the voltage between the inverter negative terminal and the battery negative terminal is a predetermined offset voltage that is different from the voltage according to the battery pack voltage.

[0018] The BMS may further include the steps of connecting the positive terminal of the inverter and the negative terminal of the battery pack via a third resistor, and diagnosing that the BMS has fused a second control relay connected between the positive terminal of the battery pack and the positive terminal of the inverter if the voltage between the positive terminal of the inverter and the negative terminal of the battery pack is a voltage corresponding to the battery pack voltage.

[0019] The BMS may further include the steps of connecting the positive terminal of the inverter and the negative terminal of the battery pack via a third resistor, and diagnosing that the second control relay connected between the positive terminal of the battery pack and the positive terminal of the inverter is not fused if the voltage between the positive terminal of the inverter and the negative terminal of the battery pack is a predetermined offset voltage different from the voltage according to the battery pack voltage. [Effects of the Invention]

[0020] Through the present disclosure, in a battery system including a battery pack, it is possible to diagnose which relay among a plurality of relays connected to the battery pack is fused by measuring the battery pack voltage, prevent the phenomenon that current flows even when the relay is opened, and provide a relay fusion diagnosis circuit and a relay fusion diagnosis method that enable safe operation of the battery pack.

Brief Description of the Drawings

[0021] [Figure 1] It is a schematic diagram schematically showing a battery system according to an embodiment. [Figure 2] It is a circuit diagram showing an example of a battery system including a fusion diagnosis circuit according to an embodiment. [Figure 3] It is a flowchart of a fusion diagnosis method for a first control relay according to an embodiment. [Figure 4] It is a flowchart of a fusion diagnosis method for a second control relay according to an embodiment.

Modes for Carrying Out the Invention

[0022] Hereinafter, the embodiments disclosed in this specification will be described in detail with reference to the accompanying drawings. The same or similar components will be denoted by the same or similar reference numerals, and redundant descriptions thereof will be omitted. The suffixes “module” and / or “section” for the components used in the following description are given or mixed only for the ease of preparing the specification, and do not have the meaning or role of being distinguished from each other by themselves. In addition, when it is determined that a specific description of related known technologies may obscure the gist of the embodiments disclosed in this specification, the detailed description thereof will be omitted. Also, the accompanying drawings are only for facilitating the understanding of the embodiments disclosed in this specification, and the technical idea disclosed in this specification is not limited by the accompanying drawings, and should be understood to include all modifications, equivalents or alternatives included in the idea and technical scope of the present invention.

[0023] Terms including ordinal numbers such as first, second, etc. can be used to describe various components, etc., but the components, etc. are not limited by the above terms, etc. The above terms are only used for the purpose of distinguishing one component from other components.

[0024] In this specification, terms such as "including" or "having" are intended to specify the existence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and do not pre-exclude the existence or addition possibility of one or more other features, etc., numbers, steps, operations, components, parts, or combinations thereof. It should be understood that this is not the case.

[0025] Among the configurations according to an embodiment, in a configuration that controls other configurations under specific control conditions, a program embodied as a set of instruction words that embody a control algorithm necessary for controlling other configurations may be installed. The control configuration can process input data and stored data according to the installed program to generate output data. The control configuration may include a non-volatile memory for storing the program and a memory for storing data.

[0026] Figures 1 to 4 illustrate a relay fusion diagnosis circuit and a relay fusion diagnosis method.

[0027] Figure 1 is a schematic diagram schematically showing a battery system according to an embodiment.

[0028] The battery system 1 includes a battery pack 10, a battery management system (Battery Management System, BMS) 20, a main relay unit 30, control relays 41, 42, and a fusion diagnosis circuit 40. The battery system 1 may be electrically connected to an inverter 2.

[0029] The battery pack 10 may include a plurality of electrically connected battery cells (not shown). For example, a predetermined number of battery cells can be connected in series to form a battery module, and a predetermined number of battery modules can be connected in series and / or parallel to supply the desired power.

[0030] The main relay section 30 may include a first main relay 31 with one end connected to the positive terminal of the battery pack 10 and a second main relay 32 with one end connected to the negative terminal of the battery pack 10. The node between the first main relay 31 and the first control relay 41 is referred to as the first node N1. The node between the first control relay 41 and the positive terminal of the inverter 2 is referred to as the second node N2. The node between the second control relay 42 and the negative terminal of the inverter 2 is referred to as the third node N3.

[0031] The other end of the first main relay 31 is connected to one end of the first control relay 41, and the other end of the second main relay 32 is connected to one end of the second control relay 42. The other end of the first control relay 41 is connected to the positive terminal of the inverter 2. The other end of the second control relay 42 is connected to the negative terminal of the inverter 2.

[0032] The BMS20 is connected to the positive and negative terminals of each of the multiple battery cells contained in the battery pack 10. The closing and opening of the first main relay 31, the second main relay 32, the first control relay 41, and the second control relay 42 are controlled by relay control signals MRS1, MRS2, CRS1, and CRS2 supplied from the BMS20.

[0033] The fusion diagnostic circuit 40 may include a plurality of resistor boxes 410, 420, 430, and 440. The operation of the plurality of resistor boxes 410, 420, 430, and 440 may be controlled by a plurality of control signals CS1 to CS4 supplied from the BMS 20. However, the invention is not limited thereto, and the fusion diagnostic circuit 40 may further include a separate control circuit that generates the plurality of control signals CS1 to CS4.

[0034] The first resistor box 410 is connected between the other end of the first main relay 31 and the other end of the second main relay 32. The second resistor box 420 is connected between the other end of the second main relay 32 and the positive terminal of the inverter 2. The third resistor box 430 is connected between the other end of the first main relay 31 and the negative terminal of the inverter 2. The fourth resistor box 440 is connected between the other end of the second main relay 32 and the negative terminal of the inverter 2.

[0035] The BMS20 can receive a pack voltage signal V_PACK corresponding to the battery pack voltage from the first resistor box 410. The battery pack voltage can correspond to the voltage between the positive terminal and the negative terminal of the battery pack. The BMS20 can receive a first voltage signal VS1 corresponding to the voltage between the positive terminal of the inverter and the negative terminal of the battery pack from the second resistor box 420. The BMS20 can receive a second voltage signal VS2 corresponding to the voltage between the negative terminal of the inverter and the negative terminal of the battery pack from the fourth resistor box 440. Since the voltage at the negative terminal of the battery pack is at ground level, the battery pack voltage is the voltage at the positive terminal of the battery pack, the voltage between the positive terminal of the inverter and the negative terminal of the battery pack is the voltage at the positive terminal of the inverter, and the voltage between the negative terminal of the inverter and the negative terminal of the battery pack may be the voltage at the negative terminal of the inverter.

[0036] A fusion diagnosis circuit and diagnostic method that can diagnose the fusion of the first and second control relays 41 and 42 by measuring multiple voltages by closing and opening the first and second main relays 31 and 32 and the first and second control relays 41 and 42 according to the measured multiple voltages will be described below with reference to Figures 2 to 4.

[0037] Figure 2 is a circuit diagram showing an example of a battery system including a fusion diagnostic circuit according to one embodiment.

[0038] According to one embodiment, the battery system 1 may include a battery pack 10, a BMS 20, a main relay unit 30, first and second control relays 41 and 42, a fusion diagnostic circuit 40, an analog-to-digital converter (ADC) 50, and an isolator 60. The battery system 1 may be electrically connected to an inverter 2. The BMS 20 may include a Main Control Unit (MCU). The explanation of the configuration in Figure 2 that overlaps with the configuration in Figure 1 is the same as the explanation for the configuration in Figure 1.

[0039] With respect to the dotted line 55 shown in Figure 2, the ground HV_GND for the high-voltage level configuration located on the left side (hereinafter referred to as the high-voltage side) and the ground LV_GND for the low-voltage level configuration located on the right side (hereinafter referred to as the low-voltage side) are different from each other. For example, the negative terminal of the battery pack 10 is connected to ground HV_GND, and the emitter terminals of multiple transistors TR1 to TR4 may be connected to the other ground LV_GND.

[0040] The fusion diagnostic circuit 40 may include a plurality of resistor boxes 410, 420, 430, 440 and a plurality of resistors R11 to R16. The first resistor box 410 may include a first resistor R1, a first photocoupler PC1, and a first transistor TR1. The first photocoupler PC1 may include a first phototransistor PT1 and a first light-emitting diode PD1. The second resistor box 4 2 0 may include a second resistor R2, a second photocoupler PC2, and a second transistor TR2. The second photocoupler PC2 may include a second phototransistor PT2 and a second light-emitting diode PD2. Third resistor box 4 3 0 may include a third resistor R3, a third photocoupler PC3, and a third transistor TR3. The third photocoupler PC3 may include a third phototransistor PT3 and a third light-emitting diode PD3. Fourth resistor box 4 40 may include a fourth resistor R4, a fourth photocoupler PC4, and a fourth transistor TR4. The fourth photocoupler PC4 may include a fourth phototransistor PT4 and a fourth light-emitting diode PD4.

[0041] Multiple photocouplers PC1 to PC4 are elements for isolating the high-voltage side from the low-voltage side. Multiple photocouplers PC1 to PC4 can be connected or disconnected by control of the MCU210.

[0042] The emitter terminal of the first transistor TR1 is connected to ground LV_GND, the collector terminal of the first transistor TR1 is connected to one end of the first light-emitting diode PD1, and the base terminal of the first transistor TR1 may be input to the first control signal CS1 supplied from the MCU210. The other end of the first light-emitting diode PD1 is input to the voltage VCC. One end of the first phototransistor PT1 is connected to one end of the first resistor R1, and the other end of the first phototransistor PT1 is connected to one end of resistor R11 and the input terminal of ADC50 at node N11. The other end of the first resistor R1 is connected to the first node N1. The other end of resistor R11 is connected to ground HV_GND.

[0043] The emitter terminal of the second transistor TR2 is connected to ground LV_GND, the collector terminal of the second transistor TR2 is connected to one end of the second light-emitting diode PD2, and the base terminal of the second transistor TR2 may be input to the second control signal CS2 supplied from the MCU210. The other end of the second light-emitting diode PD2 is input to the voltage VCC. One end of the second phototransistor PT2 is connected to one end of the second resistor R2, and the other end of the second phototransistor PT2 is connected to one end of resistor R12 and the input terminal of ADC50 at node N12. The other end of the second resistor R2 is connected to the second node N2. The other end of resistor R12 is connected to one end of resistor R13, and a predetermined offset voltage V_OFF may be applied to the node where the other end of resistor R12 and one end of resistor R13 are connected. The other end of resistor R13 is connected to ground HV_GND.

[0044] The emitter terminal of the third transistor TR3 is connected to ground LV_GND, the collector terminal of the third transistor TR3 is connected to one end of the third light-emitting diode PD3, and the base terminal of the third transistor TR3 may be input to the third control signal CS3 supplied from the MCU210. The other end of the third light-emitting diode PD3 is input to the voltage VCC. One end of the third phototransistor PT3 is connected to one end of the third resistor R3, and the other end of the third phototransistor PT3 is connected to one end of resistor R14. The other end of the third resistor R3 is connected to the first node N1. The other end of resistor R14 is connected to the third node N3.

[0045] The emitter terminal of the fourth transistor TR4 is connected to ground LV_GND, the collector terminal of the fourth transistor TR4 is connected to one end of the fourth light-emitting diode PD4, and the base terminal of the third transistor TR3 may be input to the fourth control signal CS4 supplied from the MCU210. The other end of the fourth light-emitting diode PD4 is input to the voltage VCC. One end of the fourth phototransistor PT4 is connected to one end of the fourth resistor R4, and the other end of the fourth phototransistor PT4 is connected to one end of resistor R15 and the input terminal of ADC50 at node N13. The other end of the fourth resistor is connected to the third node N3. The other end of resistor R15 is connected to one end of resistor R16, and a predetermined offset voltage V_OFF may be applied to the node where the other end of resistor R15 and one end of resistor R16 are connected. The other end of resistor R16 is connected to ground HV_GND.

[0046] The on-level of multiple control signals CS1 to CS4 may be high, and the off-level may be low. In other words, the high-level control signals CS1 to CS4 may turn on multiple transistors TR1 to TR4 and sink current, while the low-level control signals CS1 to CS4 may turn off multiple transistors TR1 to TR4.

[0047] When a high-level first control signal CS1 is supplied from MCU210, the first transistor TR1 turns on, and current flows through the first light-emitting diode PD1, causing it to emit light. The emission of light from the first light-emitting diode PD1 turns on the first phototransistor PT1. When a high-level second control signal CS2 is supplied from MCU210, the second transistor TR2 turns on, and current flows through the second light-emitting diode PD2, causing it to emit light. The emission of light from the second light-emitting diode PD2 turns on the second phototransistor PT2. When a high-level third control signal CS3 is supplied from MCU210, the third transistor TR3 turns on, and current flows through the third light-emitting diode PD3, causing it to emit light. The emission of light from the third light-emitting diode PD3 turns on the third phototransistor PT3. When a high-level fourth control signal CS4 is supplied from MCU210, the fourth transistor TR4 turns on, and current flows through the fourth light-emitting diode PD4, causing it to emit light. The emission of light from the fourth light-emitting diode PD4 turns on the fourth phototransistor PT 4 It turns on.

[0048] ADC50 can receive a packed voltage signal V_PACK via an input terminal connected to node N11, a first voltage signal VS1 from an input terminal connected to node N12, and a second voltage signal VS2 from an input terminal connected to node N13. ADC50 can convert the received packed voltage signal V_PACK, the first voltage signal VS1, and the second voltage signal VS2 into multiple digital signals D_V_PACK, D_VS1, and D_VS2, respectively, and transmit them to the isolator 60.

[0049] The isolator 60 isolates the high-voltage side from the low-voltage side, allowing it to transmit multiple digital signals D_V_PACK, D_VS1, and D_VS2 received from the ADC 50 to the MCU 210.

[0050] The MCU210 can diagnose the fusion splicing of the first control relay 41 and / or the second control relay 42 based on multiple digital signals D_V_PACK, D_VS1, and D_VS2 received from the isolator 60.

[0051] Figure 3 is a flowchart of a fusion splicing diagnostic method for a first control relay according to one embodiment. During steps S11 to S12 in Figure 3, the first main relay 31 and the second main relay 32 are in a closed state.

[0052] The BMS20 can derive the battery pack voltage based on the pack voltage signal V_PACK, which corresponds to the battery pack positive terminal voltage V_PP (S11).

[0053] The MCU210 can generate a high-level first control signal CS1 to derive the battery pack voltage. The remaining control signals CS2 to CS4 may be low levels. The high-level first control signal CS1 turns on the first transistor TR1, causing current to flow, the first light-emitting diode PD1 to light up, and the first phototransistor PT1 to turn on. When the first phototransistor PT1 is turned on, the ADC50 can receive a pack voltage signal V_PACK corresponding to the battery pack voltage. For example, the pack voltage signal V_PACK may be the voltage at node N11, where the battery positive terminal voltage V_PP is distributed by the first resistors R1 and R11. Since the battery negative terminal is at ground level, the battery pack voltage follows the battery positive terminal voltage V_PP.

[0054] The ADC50 can convert the received pack voltage signal V_PACK into a digital signal D_V_PACK and transmit it to the isolator 60. The isolator 60 can transmit the received digital signal D_V_PACK to the MCU210. The MCU210 can derive the battery pack voltage for the battery pack 10 based on the digital signal D_V_PACK.

[0055] The BMS20 can derive a first voltage, which is the voltage difference between the inverter positive terminal and the battery pack negative terminal, based on a first voltage signal VS1 corresponding to the inverter positive terminal voltage V_IP, when the first control relay 41 is opened (S12). In step S12, the second control relay 42 may also be opened. When the first control relay 41 is opened, the MCU210 supplies a control signal CRS1 that causes the first control relay 41 to open.

[0056] The MCU210 can generate a high-level second control signal CS2 to derive the first voltage. The remaining control signals CS1, CS3, and CS4 may be low levels. When the high-level second control signal CS2 turns on the second transistor TR2, current flows, the second light-emitting diode PD2 lights up, and the second phototransistor PT2 turns on, the ADC50 can receive the first voltage signal VS1, which is the voltage at node N12.

[0057] The ADC50 can convert the received first voltage signal VS1 into a digital signal D_VS1 and transmit it to the isolator 60. The isolator 60 can transmit the received digital signal D_VS1 to the MCU210. The MCU210 can derive a first voltage based on the digital signal D_VS1. The first voltage can represent the voltage difference between the inverter positive terminal and the battery pack negative terminal.

[0058] The BMS20 can determine whether the first voltage derived in step S12 is a voltage corresponding to the battery pack voltage (S13).

[0059] The BMS20 can diagnose that the first control relay 41 is fused if the first voltage derived in step S12 is a voltage corresponding to the battery pack voltage (S14).

[0060] When the first control relay 41 is open and fused, node N2 is connected to the positive terminal of the battery pack, and the voltage at node N12 may be a voltage that follows the positive terminal voltage V_PP of the battery pack. In other words, when the first control relay 41 is fused, the positive terminal voltage V_PP of the battery pack is distributed by the second resistor R2, resistor R12, and resistor R13, and the voltage at node N12 is a voltage different from the offset voltage. When the first control relay 41 is fused, the voltage at node N12 is shown in the following [Equation 1].

number

[0061] The BMS20 can diagnose that the first control relay 41 is in a normal state if the first voltage derived in step S12 is not a voltage that follows the battery pack voltage (S15). When the first control relay 41 is in a normal state, node N2 is isolated from the positive terminal of the battery pack, so the voltage at node N12 may be a predetermined offset voltage V_OFF. The first control relay 41 can be considered in a normal state even when it is not fused.

[0062] Figure 4 is a flowchart of a fusion splicing diagnostic method for a second control relay according to one embodiment. During steps S21 to S22 in Figure 4, the first main relay 31 and the second main relay 32 are in a closed state.

[0063] The BMS20 can derive the battery pack voltage based on the pack voltage signal V_PACK, which corresponds to the battery pack positive terminal voltage V_PP (S21). The explanation for this is the same as the explanation for step S11.

[0064] BMS20 is the second control relay 4 2Under the open condition for the first control relay 41, a second voltage, which is the voltage difference between the battery negative terminal and the inverter negative terminal, can be derived based on the second voltage signal VS2 corresponding to the inverter negative terminal voltage V_IN (S22). In step S22, the first control relay 41 may be opened. 2 In response to the release condition, the MCU210 supplies a control signal CRS2 that causes the second control relay 42 to open.

[0065] Since both the battery pack's negative terminal and the inverter's negative terminal are at ground level, conventionally, even when the second control relay was fused under open control conditions, it was difficult to detect the voltage difference between the battery's negative terminal and the inverter's negative terminal.

[0066] In one embodiment disclosed herein, the battery pack positive terminal voltage V_PP is supplied to node N3 via the third resistor box 430. Thus, the inverter negative terminal voltage V_IN, unlike conventional designs, is at a level corresponding to the battery pack positive terminal voltage V_PP and is at a different level from the battery pack negative terminal voltage V_PN. In other words, when the second control relay 42 is not fused under open control conditions, a voltage difference occurs between the inverter negative terminal voltage and the battery pack negative terminal, allowing the fusion of the second control relay 42 to be detected based on the inverter negative terminal voltage V_IN.

[0067] The MCU210 can generate a high-level third control signal CS3 and a high-level fourth control signal CS4 to derive a second voltage. The remaining control signals CS1 and CS2 may be low levels. The high-level third control signal CS3 turns on the third transistor TR3, causing current to flow, the third light-emitting diode PD3 to light up, and the third phototransistor PT3 to turn on. The high-level fourth control signal CS4 turns on the fourth transistor TR4, causing current to flow, the fourth light-emitting diode PD4 to light up, and the fourth phototransistor PT4 to turn on. When the third phototransistor PT3 and the fourth phototransistor PT4 are turned on, the ADC50 can receive a second voltage signal VS2 corresponding to the inverter negative terminal voltage V_IN.

[0068] The ADC50 can convert the received second voltage signal VS2 into a digital signal D_VS2 and transmit it to the isolator 60. The isolator 60 can transmit the received digital signal D_VS2 to the MCU210. The MCU210 can derive a second voltage based on the digital signal D_VS2. The second voltage can represent the voltage difference between the inverter negative terminal and the battery pack negative terminal.

[0069] The BMS20 can determine whether the second voltage derived in step S22 is a voltage that corresponds to the battery pack voltage (S23).

[0070] The BMS20 can diagnose that the second control relay 42 is in a normal state if the second voltage derived in step S22 is a voltage that corresponds to the battery pack voltage (S24). The second control relay 42 can be considered to be in a normal state if it is not fused.

[0071] When the second control relay 42 is in a normal state, node N3 is isolated from the negative terminal of the battery pack, so the voltage at node N13 may be a voltage that follows the positive terminal voltage V_PP of the battery pack. In other words, when the second control relay 42 is in a normal state, the positive terminal voltage V_PP of the battery pack is distributed by the third resistor R3, the fourth resistor R4, resistor R14, resistor R15, and resistor R16, and the voltage at node N13 is a voltage different from the offset voltage. The second control relay 42 can be considered in a normal state when it is not fused. When the second control relay 42 is in a normal state, the voltage at node N13 is given by the following [Equation 2].

number

[0072] The BMS20 can diagnose that the second control relay 42 is fused if the second voltage derived in step S22 is not a voltage corresponding to the battery pack voltage (S25).

[0073] When the second control relay 42 is fused, node N3 is connected to the negative terminal of the battery pack, and the voltage at node N13 may be a predetermined offset voltage V_OFF.

[0074] Steps S11-S15 in Figure 3 and steps S21-S25 in Figure 4 may be performed simultaneously, or they may be performed in the order of S11-S15 followed by S21-S25, or vice versa.

[0075] Although embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto. Various modifications and improvements made by persons with ordinary skill in the art to which the present invention belongs also fall within the scope of the present invention. [Explanation of symbols]

[0076] 1. Battery System 2 Inverters 10 Battery Packs 20. Battery Management System (BMS) 30 Main relay section 31. Main Relay 1 32. Second Main Relay 40 Fusion diagnostic circuit 41 Control Relay 42 Second control relay 42 Control Relays 50 Analog-to-Digital Converters (ADCs) 60 Isolators 410 Resistor Box 420 Resistor Box 430 Resistor Box 440 Resistor Box

Claims

1. Battery pack and A first main relay with one end connected to the positive terminal of the battery pack and a second main relay with one end connected to the negative terminal of the battery pack, A first control relay connected between the first main relay and the positive terminal of the inverter, and a second control relay connected between the second main relay and the negative terminal of the inverter, A fusion splice diagnostic circuit including a first resistor and a first photocoupler connected between the other end of the first main relay and the negative terminal of the inverter, and a second resistor and a second photocoupler connected between the negative terminal of the inverter and the other end of the second main relay, A battery system comprising a Battery Management System (BMS) that drives the first and second photocouplers to diagnose the fusion of the second control relay.

2. The aforementioned BMS is The battery system according to claim 1, wherein, under the open control condition of the second control relay, a first control signal for driving the first photocoupler and a second control signal for driving the second photocoupler are transmitted to the fusion diagnostic circuit, and when the first and second photocouplers are driven by the first and second control signals, a first voltage signal corresponding to the negative terminal of the inverter is received.

3. The aforementioned BMS is The battery system according to claim 2, wherein a first voltage difference corresponding to the negative terminal of the inverter and the negative terminal of the battery pack is derived based on the first voltage signal.

4. The aforementioned BMS is The battery system according to claim 3, wherein if the first voltage difference is a voltage corresponding to the battery pack voltage between the positive terminal and the negative terminal of the battery pack, it is diagnosed that the second control relay is not fused.

5. The aforementioned BMS is The battery system according to claim 3, wherein if the first voltage difference is a predetermined offset voltage that is different from the voltage according to the battery pack voltage between the positive terminal and the negative terminal of the battery pack, it is diagnosed that the second control relay is fused.

6. The fusion diagnostic circuit is, The system further includes a third resistor and a third photocoupler connected between the positive terminal of the inverter and the other end of the second main relay. The battery system according to claim 1, wherein the BMS drives the third photocoupler to diagnose the fusion of the first control relay.

7. The aforementioned BMS is The battery system according to claim 6, wherein, under the open control condition of the first control relay, a third control signal is transmitted to the fusion diagnostic circuit to drive the third photocoupler, and when the third photocoupler is driven by the third control signal, a second voltage signal corresponding to the positive terminal of the inverter is received.

8. The aforementioned BMS is The battery system according to claim 7, wherein a second voltage difference corresponding to the positive terminal of the inverter and the negative terminal of the battery pack is derived based on the second voltage signal.

9. The aforementioned BMS is The battery system according to claim 8, wherein if the second voltage difference is a voltage corresponding to the battery pack voltage between the positive terminal and the negative terminal of the battery pack, it is diagnosed that the first control relay is fused.

10. The aforementioned BMS is The battery system according to claim 8, wherein if the second voltage difference is a predetermined offset voltage different from the voltage according to the battery pack voltage between the positive terminal and the negative terminal of the battery pack, it is diagnosed that the first control relay is not fused.

11. The BMS derives a battery pack voltage corresponding to the voltage between the positive and negative terminals of the battery pack based on the voltage at the positive terminal of the battery pack, The step of driving the first and second photocouplers to derive the voltage between the negative terminal of the inverter and the negative terminal of the battery pack, By driving the first photocoupler, the positive terminal of the battery pack and the negative terminal of the inverter are connected via the first resistor and the first photocoupler. By driving the second photocoupler, the negative terminal of the inverter and the negative terminal of the battery pack are connected via the second resistor and the second photocoupler, step, A relay fusion diagnosis method comprising the step of diagnosing that if the voltage between the negative terminal of the inverter and the negative terminal of the battery pack is a voltage corresponding to the battery pack voltage, the BMS diagnoses that the first control relay connected between the negative terminal of the battery pack and the negative terminal of the inverter is not fused.

12. The relay fusion diagnosis method according to claim 11, further comprising the step of diagnosing that the BMS is fused if the voltage between the negative terminal of the inverter and the negative terminal of the battery pack is a predetermined offset voltage that is different from the voltage according to the battery pack voltage.

13. The steps of driving the third photocoupler so that the positive terminal of the inverter and the negative terminal of the battery pack are connected via the third resistor and the third photocoupler, The relay fusion diagnosis method according to claim 11, further comprising the step of diagnosing that a second control relay connected between the positive terminal of the battery pack and the positive terminal of the inverter is fused if the voltage between the positive terminal of the inverter and

14. The steps of driving the third photocoupler so that the positive terminal of the inverter and the negative terminal of the battery pack are connected via the third resistor and the third photocoupler, The relay fusion diagnosis method according to claim 11, further comprising the step of: if the voltage between the positive terminal of the inverter and the negative terminal of the battery pack is a predetermined offset voltage that is different from the voltage according to the battery pack voltage, the BMS diagnoses that the second control relay connected between the positive terminal of the battery pack and the positive terminal of the inverter is not fused.

Images