System main relay deposition inspection method

Abstract

The present invention relates to a welding inspection method for a system main relay provided between a high-voltage battery mounted in a vehicle and one or more auxiliary loads, the welding inspection method comprising: after a power supply system of the vehicle is stopped, welding the high-voltage battery with the auxiliary loads; stopping the supply of power from the high-voltage battery to the auxiliary load; a step of performing a weld inspection of the system main relay after the supply of power to the auxiliary load is stopped; and a step of starting power supply to the auxiliary load in response to a request from the auxiliary load when the result of the deposition inspection is that the system main relay is not deposited.

Description

Technical Field

[0001] This disclosure relates to a method for checking whether a system main relay installed between a high-voltage battery mounted in a vehicle and one or more auxiliary loads has a fused connection. Background Technology

[0002] Japanese Patent Application Publication No. 2023-156719 discloses a method as follows: when the main switch of a vehicle is turned off while the main relay of the system is turned on, if there is a specific auxiliary load (with the auxiliary battery as the main power source) that operates after the main switch is turned off, power is supplied from the high-voltage battery to the specific auxiliary load while the main relay of the system is turned on.

[0003] In OBD (On-Board Diagnostics) regulations, there is a necessary condition that the main relay of the system must be checked for fusion at a specified monitoring rate.

[0004] In the technology described in Japanese Patent Application Publication No. 2023-156719, when a specific auxiliary load operates after the main switch is disconnected, the system main relay is kept in the ON state. Therefore, it is impossible to perform a fuse check on the system main relay. Therefore, as a countermeasure to meet the requirements of OBD regulations, it is possible to perform a fuse check on the system main relay by forcibly stopping the power supply from the high-voltage battery to the specific auxiliary load after the main switch is disconnected.

[0005] However, during periods when power supply from the high-voltage battery to a specific auxiliary load is stopped, only the auxiliary battery's power is consumed by the operation of that specific auxiliary load. Therefore, it is possible for the auxiliary battery to be depleted. Summary of the Invention

[0006] This disclosure was made in view of the above-mentioned problems, and its object is to provide a method for performing a system main relay welding check that can suppress the depletion of the auxiliary battery when the welding check of the system main relay is performed after the main switch of the vehicle is turned off.

[0007] To address the aforementioned issues, one technical solution disclosed herein is a method for checking the fusion of a system main relay. The system main relay is located between a high-voltage battery mounted in a vehicle and one or more auxiliary loads. The method includes: stopping power supply from the high-voltage battery to the auxiliary loads after the vehicle is in a Ready-OFF (power system off) state; performing a fusion check on the system main relay after stopping power supply to the auxiliary loads; and, if the fusion check results in the system main relay not being fused, starting power supply to the auxiliary loads upon request from the auxiliary loads.

[0008] According to the above-disclosed method for checking the fuse bonding of the main relay of the system, when the fuse bonding of the main relay of the system is checked after the main switch of the vehicle is turned off, the depletion of the auxiliary battery can be suppressed. Attached Figure Description

[0009] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, wherein the same symbols denote the same elements, wherein:

[0010] Figure 1 This is a functional block diagram of a control unit and its peripheral parts used to implement a system main relay welding inspection method according to an embodiment of the present disclosure.

[0011] Figure 2A This is a flowchart illustrating a system main relay welding inspection method according to one embodiment of the present disclosure.

[0012] Figure 2B This is a flowchart illustrating a system main relay welding inspection method according to one embodiment of the present disclosure.

[0013] Figure 3 This is a timing diagram illustration for situations where there is an IGB-ON (IGB-connect) request based on other factors.

[0014] Figure 4 This is a timing diagram example in the absence of IGB-ON requests based on other factors. Detailed Implementation

[0015] The system main relay welding inspection method disclosed herein, when stopping the power supply from the high-voltage battery to the auxiliary load after the vehicle is Ready-OFF (power system shut down) in order to perform the welding inspection of the system main relay, in principle makes this stop temporary and quickly resumes the power supply from the high-voltage battery to the auxiliary load after the welding inspection. This suppresses the depletion of the auxiliary battery.

[0016] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.

[0017] Implementation

[0018] constitute

[0019] Figure 1 This is a functional block diagram of a control unit 60 and its peripheral parts used to implement a system main relay welding inspection method according to an embodiment of the present disclosure. Figure 1The functional blocks shown include a high-voltage battery 10, a system main relay (SMR) 20, a DC-DC converter (DDC) 30, an auxiliary battery 40, multiple auxiliary loads 51 and 52, and a control unit 60. Among them, in... Figure 1 In the diagram, solid lines represent power signal lines, and dashed lines represent control / communication signal lines.

[0020] The system's main relay welding inspection method can be applied to vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs) that use electric motors as a power source.

[0021] The high-voltage battery 10, such as a lithium-ion battery, is a rechargeable secondary battery that primarily supplies power to starter motors, drive motors, and other motors (not shown). This high-voltage battery 10 can supply power to auxiliary loads 51 and 52 via the system main relay 20 and the DC-DC converter 30.

[0022] The system main relay 20 is a switching element used to control the power supply and acceptance state of the high-voltage battery 10, and is disposed between the high-voltage battery 10 and the DC-DC converter 30. As the system main relay 20, a mechanical relay having movable and fixed terminals can be exemplified. The system main relay 20 can switch between a state of electrical connection between the input and output terminals (relay on) and a state of electrical disconnection between the input and output terminals (relay off) based on instructions from the control unit 60.

[0023] The DC-DC converter 30 is a power converter capable of converting input power into power of a specified voltage and outputting it. The first terminal of the DC-DC converter 30 is connected to the high-voltage battery 10 via the system main relay 20, and the second terminal is connected to the auxiliary battery 40, auxiliary load 51, and auxiliary load 52. The DC-DC converter 30 can supply power output from the high-voltage battery 10 connected to the first terminal to the auxiliary battery 40, auxiliary load 51, and auxiliary load 52 connected to the second terminal. The operation of the DC-DC converter 30 is controlled by the control unit 60.

[0024] The auxiliary battery 40, such as a lead-acid battery or a lithium-ion battery, is a rechargeable secondary battery that supplies power to multiple auxiliary loads 51 and 52. This auxiliary battery 40 is connected to the DC-DC converter 30 in a manner that allows it to be charged by the high-voltage battery 10. Typically, the auxiliary battery 40 is set to have a lower rated voltage than the high-voltage battery 10.

[0025] Auxiliary loads 51 and 52 are devices mounted on the vehicle and consume necessary power to perform prescribed operations. These auxiliary loads 51 and 52 include specific auxiliary loads that consume power when the vehicle's power system is off (Ready-OFF), such as when the vehicle is parked (e.g., in-vehicle equipment such as a dashcam with parking monitoring function). Auxiliary loads 51 and 52 operate using power supplied from the high-voltage battery 10 via the system main relay 20 and the DC-DC converter 30, and power stored in the auxiliary battery 40. Figure 1 The example shown is of two auxiliary loads 51 and 52 mounted on a vehicle, but the number of auxiliary loads mounted on a vehicle is not limited thereto.

[0026] The control unit 60 is configured to control the power supply from the high-voltage battery 10 to the auxiliary battery 40 and auxiliary loads 51 and 52 by operating the on / off action of the system main relay 20. This control unit 60 has at least the following functions: "IGSW control," "auxiliary power supply control," "auxiliary load control," "power supply control," "system control," and "SMR welding check." "IGSW control" controls the ON / OFF state of the IGB. "Auxiliary power supply control" controls the power supply to specific auxiliary loads when Ready-OFF. "Auxiliary load control" controls auxiliary loads 51 and 52. "Power supply control" controls the power supply for starting the DC-DC converter 30. "System control" controls the power supply from the high-voltage battery 10 to the auxiliary loads 51 and 52 via the DC-DC converter 30. "SMR welding check" determines whether the movable and fixed terminals of the system main relay 20 are not in a welded state. These functions can be communicatively connected via networks such as CAN (Controller Area Network).

[0027] This control unit 60 can typically be composed, in whole or in part, of an electronic control unit (ECU), including a processor such as a microcomputer, memory, and input / output interfaces. For example, the aforementioned IGSW control, auxiliary power supply control, and auxiliary load control functions can be included in the extended body ECU, while the power control, system control, and SMR welding inspection functions can be included in the HV-ECU. This electronic control unit can achieve some or all of the aforementioned functions by reading and executing the program stored in memory through the processor.

[0028] control

[0029] Next, further reference Figure 2A and Figure 2BThis embodiment describes the system main relay welding inspection method. Figure 2A and Figure 2B This is a flowchart illustrating the processing steps of the SMR welding inspection performed by the control unit 60. Figure 2A processing and Figure 2B The processing is connected by the connectors X, Y, and Z, respectively.

[0030] Should Figure 2A and Figure 2B The SMR welding inspection shown begins when the ignition switch is turned off and the vehicle is in the Ready-OFF state.

[0031] S301

[0032] The control unit 60 determines whether a fuse check of the system main relay 20 needs to be performed. This determination can be made, for example, by whether the fuse check of the system main relay 20 has been unable to be performed for a specified period due to reasons such as the operation of specific auxiliary loads after the vehicle is Ready-OFF. The specified period is set based on the requirements of OBD regulations. The necessity of a fuse check of the system main relay 20 is determined, for example, by the HV-ECU (SMR fuse check function).

[0033] If the control unit 60 determines that a welding check of the system main relay 20 is required (S201, Yes), the process proceeds to S202.

[0034] On the other hand, if the control unit 60 determines that the welding check of the system main relay 20 is not required (S201, No), the process proceeds to S213.

[0035] S302

[0036] The control unit 60 performs a process to temporarily stop the auxiliary power supply control; in other words, it disconnects the request for auxiliary power supply control. As a specific example of this process, firstly, the HV-ECU (system control function) sends a signal to the extended body ECU (auxiliary power supply control function) requesting a "temporary stop of auxiliary power supply control." Then, upon receiving this signal, the extended body ECU (auxiliary power supply control function) sends a signal to the HV-ECU (system control function) indicating "no request for auxiliary power supply control." Furthermore, it sends a request to the extended body ECU (IGSW control function) to "IGB-OFF related to auxiliary power supply control." Additionally, the extended body ECU sets its CAN communication with the HV-ECU to sleep mode disabled.

[0037] If the auxiliary machine power supply control is temporarily stopped through the control unit 60, the process proceeds to S203.

[0038] S203

[0039] The control unit 60 performs IGB-OFF processing related to auxiliary power supply control. As a specific example of this processing, it can be shown that the extended body ECU (IGSW control function), upon receiving a request for "IGB-OFF related to auxiliary power supply control," outputs an IGB-OFF signal to the HV-ECU (power control function). Through this processing, the power supply to the DC-DC converter 30 is disconnected, and the power supply from the high-voltage battery 10 to the auxiliary loads 51 and 52 ceases.

[0040] If the control unit 60 performs the IGB-OFF process related to auxiliary power supply control, the process proceeds to S204.

[0041] S204

[0042] The control unit 60 performs a welding check on the system main relay 20. This process is performed by the HV-ECU (SMR welding check function). The welding check on the system main relay 20 can be performed using known methods such as monitoring the terminal voltage of the system main relay 20 by implementing voltage fluctuation processing.

[0043] If the control unit 60 performs a welding check on the system main relay 20, the process proceeds to S205.

[0044] S205

[0045] The control unit 60 determines whether the system main relay 20 has experienced welding. This determination is made by the HV-ECU (SMR Welding Check Function). For example, if the voltages of both terminals of the system main relay 20 are the same despite voltage fluctuations, it can be determined that the fixed terminal and the movable terminal (one or both of the positive and negative sides) are welded together.

[0046] If the control unit 60 determines that the system main relay 20 is not fused (S205: none), the process proceeds to S206.

[0047] On the other hand, if the control unit 60 determines that the system main relay 20 has experienced a weld (S205, yes), the SMR weld inspection ends.

[0048] S206

[0049] The control unit 60 determines the result of whether auxiliary power supply control is feasible. This determination refers to whether, for a specific auxiliary load (such as a dashcam), power supply from the high-voltage battery 10 can be started (capable of starting) or cannot be started (cannot start). This determination is based on the result of the auxiliary power supply control feasibility determination performed before the IGB-OFF operation related to auxiliary power supply control in S203 described above. After temporarily halting the auxiliary power supply control, the result of this feasibility determination is received by the extended vehicle ECU (auxiliary power supply control function) from the HV-ECU (system control).

[0050] If the control unit 60 determines that the auxiliary machine power supply control can be started (S206, can start), the process proceeds to S208.

[0051] On the other hand, if the control unit 60 determines that the auxiliary power supply control cannot be started (S206, cannot start), the SMR welding check ends. In this case, the state where the extended body ECU (auxiliary power supply control function) requests "IGB-OFF related to auxiliary power supply control" from the extended body ECU (IGSW control function) remains unchanged, and CAN communication is in sleep mode. Furthermore, the "request for auxiliary power supply control" shown before performing IGB-OFF related to auxiliary power supply control is discarded.

[0052] Alternatively, if the control unit 60 determines that it has not received the result of the auxiliary machine power supply control determination (S206, not received), the process proceeds to S207.

[0053] S207

[0054] The control unit 60 determines whether a first time has elapsed since the IGB-OFF operation related to the auxiliary power supply control in S203 described above. This determination is performed to decide whether to maintain the temporarily suspended auxiliary power supply control in its original state if no result is received regarding whether the auxiliary power supply control is permissible. The first time can be set arbitrarily, for example, it can be set to 35 seconds.

[0055] If the control unit 60 determines that a first time has elapsed since the IGB-OFF operation related to auxiliary power supply control was initiated (S207, Yes), the SMR welding check ends. In this case, the request from the extended body ECU (auxiliary power supply control function) to the extended body ECU (IGSW control function) for "IGB-OFF operation related to auxiliary power supply control" remains unchanged, and CAN communication is in sleep mode. Furthermore, the "request for auxiliary power supply control" shown before the IGB-OFF operation related to auxiliary power supply control is discarded. Also, auxiliary power supply control for specific auxiliary loads is disabled until the next Ready-ON (power system operation).

[0056] On the other hand, if the control unit 60 determines that no first time has elapsed since the IGB-OFF operation involving auxiliary power supply control was performed (S207, No), the process proceeds to S206.

[0057] S208

[0058] Control unit 60 determines whether an IGB-ON request based on other factors exists. An IGB-ON request based on other factors is not an IGB-ON request for auxiliary power supply control related to a specific auxiliary load, but rather an IGB-ON request for auxiliary power supply control related to auxiliary loads other than the specific auxiliary load (e.g., air conditioning, battery, charging, etc.). IGB-ON requests based on other factors are received by the extended body ECU (IGSW control function).

[0059] If the control unit 60 determines that there is an IGB-ON request based on other factors (S208, yes), the process proceeds to S209.

[0060] On the other hand, if the control unit 60 determines that there is no IGB-ON request based on other factors (S208, none), the process proceeds to S210.

[0061] S209

[0062] The control unit 60 determines whether the auxiliary power supply control status is undetermined. If the auxiliary power supply control status is undetermined, the extended body ECU (auxiliary power supply control function) can receive this information from the HV-ECU (system control function) after temporarily halting the auxiliary power supply control status. Figure 3 The timing diagram shows the status of each control and request in the case of IGB-ON requests based on other factors.

[0063] If the control unit 60 detects that the status of the auxiliary machine power supply control is undetermined (S209, Yes), the process proceeds to S211.

[0064] On the other hand, if the control unit 60 does not detect that the auxiliary power supply control status is not determined (S209, No), this SMR welding inspection ends.

[0065] S210

[0066] The control unit 60 determines whether a second time interval has been detected as a disruption in CAN communication between the extended body ECU and the HV-ECU. This second time interval is set to any time required to determine if a communication interruption has occurred, for example, it can be set to 1 second. Figure 4 The timing diagram shows the status of each control and request in the absence of IGB-ON requests based on other factors.

[0067] If the control unit 60 detects a communication interruption between the extended body ECU and the HV-ECU for more than a second time (S210, yes), the process proceeds to S211.

[0068] On the other hand, if the control unit 60 does not detect a communication interruption between the extended body ECU and the HV-ECU for more than a second time (S210, No), this SMR welding inspection ends.

[0069] S211

[0070] The control unit 60 performs IGB-ON processing related to auxiliary power supply control. As a specific example of this processing, it can be shown that the extended body ECU (auxiliary power supply control function) sends a request for "IGB-ON related to auxiliary power supply control" to the extended body ECU (IGSW control function).

[0071] If the control unit 60 performs the processing of IGB-ON related to auxiliary power supply control, the processing proceeds to S212.

[0072] S212

[0073] The control unit 60 performs a process to restore the state of the auxiliary power supply control from a temporary suspension. As a specific example of this process, it can be shown that the process of extending the body ECU (auxiliary power supply control function) restores the result of the auxiliary power supply control determination shown before performing IGB-OFF related to auxiliary power supply control, that is, "there is a request for auxiliary power supply control" (request to start).

[0074] If the auxiliary machine power supply control state is restored from temporary stop by the control unit 60, the process proceeds to S213.

[0075] S213

[0076] The control unit 60 implements auxiliary power supply control, which supplies power from the high-voltage battery 10 to the auxiliary battery 40, auxiliary load 51, and auxiliary load 52 via the system main relay 20 and the DC-DC converter 30. This control is performed by the extended body ECU (auxiliary power supply control function).

[0077] If the auxiliary power supply control is implemented by the control unit 60, the SMR welding inspection is completed.

[0078] Function / Effect

[0079] As explained above, according to one embodiment of the system main relay welding inspection method of this disclosure, it is sometimes necessary to determine whether the system main relay 20, which is installed between the high-voltage battery 10 mounted in the vehicle and one or more auxiliary loads 51 and 52, has welded. In this case, after the vehicle is Ready-OFF, the power supply from the high-voltage battery 10 to the auxiliary loads 51 and 52 is temporarily stopped, and then the welding inspection of the system main relay 20 is performed. Moreover, if the welding inspection result shows that the system main relay 20 has not welded, the power supply to the auxiliary loads 51 and 52 is quickly resumed upon request.

[0080] This method can suppress the depletion of the auxiliary battery 40 during the welding check of the main relay 20 after the vehicle is ready-off.

[0081] The above describes one embodiment of the present disclosure. However, in addition to the system main relay welding inspection method, the present disclosure can also be understood as a control unit that performs the method, a program for performing the method, a computer-readable non-transitory recording medium storing the program, a vehicle equipped with the control unit, etc.

[0082] The method disclosed herein can be used in situations where it is desirable to suppress the depletion of auxiliary batteries when performing a welding inspection of the main relay of a system.

Claims

1. A method for inspecting the fusion bonding of a system main relay, wherein the system main relay is disposed between a high-voltage battery mounted in a vehicle and one or more auxiliary loads, wherein, The method for inspecting the fusion of the system's main relay includes: After the vehicle enters a power system shutdown state, the step of stopping the power supply from the high-voltage battery to the auxiliary load is performed. After stopping the power supply to the auxiliary load, the procedure of performing a fusion check on the system's main relay is performed; and If the result of the welding inspection is that the main relay of the system is not welded, the step of starting the power supply to the auxiliary load according to the request from the auxiliary load is initiated.

2. The method for inspecting the fusion bonding of the system main relay according to claim 1, wherein, In the step of stopping the power supply to the auxiliary load, if the welding check of the system main relay cannot be performed for a specified period of time because a specific auxiliary load operates after the vehicle becomes a power system shutdown state, the power supply from the high-voltage battery to the auxiliary load is stopped.

3. The method for inspecting the fusion bonding of the system main relay according to claim 2, wherein, The specific auxiliary load is a dashcam that enables parking monitoring after the vehicle's power system has stopped.

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