Vehicle power supply unit

Abstract

To easily extend life of a device including a relay.SOLUTION: An on-vehicle power supply device 10 is used in an on-vehicle power supply system 100. The on-vehicle power supply system 100 includes: a battery 20; a capacitor 22; and a power path 21 provided between the battery 20 and the capacitor 22. The on-vehicle power supply device 10 includes a relay 51 and a parallel circuit 52 provided in parallel with the relay 51. The parallel circuit 52 has a configuration in which a parallel relay 53 and a resistance unit 54 are connected in series. Multiple relay circuits 50 each composed of the relay 51 and the parallel circuit 52 are provided on the power path 21 between the battery 20 and the capacitor 22.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an in-vehicle power supply device. [Background technology]

[0002] The battery system disclosed in Patent Document 1 closes a relay that electrically connects the load device and the battery after preliminary charging by a precharge circuit. This configuration suppresses the inrush current that flows through the relay when the relay is closed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-78196 Summary of the Invention [Problem to be solved by the invention]

[0004] However, even if the inrush current is suppressed, the relay will continue to deteriorate as it is repeatedly turned on and off. As the deterioration progresses, the relay will eventually become unusable and the device including the relay will need to be replaced.

[0005] The present disclosure aims to provide a technique that can easily extend the life of a device that includes a relay. [Means for solving the problem]

[0006] The in-vehicle power supply device of the present disclosure comprises: An in-vehicle power supply device for use in an in-vehicle power supply system including a battery, a capacitor, and a power path provided between the battery and the capacitor, Relay and a parallel circuit provided in parallel with the relay, the parallel circuit is configured by connecting a parallel relay and a resistor unit in series, A plurality of relay circuits each composed of the relay and the parallel circuit are provided in the power path between the battery and the capacitor. [Effects of the Invention]

[0007] The technology according to the present disclosure makes it easy to extend the life of devices that include relays. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a circuit diagram that schematically shows an in-vehicle power supply system that includes an in-vehicle power supply device according to a first embodiment. [Figure 2] FIG. 2 is an explanatory diagram for explaining the operation when the in-vehicle power supply device selects the first relay circuit as the relay circuit to be switched and executes the first control. [Figure 3] FIG. 3 is an explanatory diagram for explaining the operation when the in-vehicle power supply device executes the second control. [Figure 4] FIG. 4 is an explanatory diagram for explaining the operation when the in-vehicle power supply device selects the second relay circuit as the relay circuit to be switched and executes the first control. [Figure 5] FIG. 5 is a flowchart showing the flow of processing executed by the in-vehicle power supply device of the first embodiment. [Figure 6] FIG. 6 is a circuit diagram that schematically shows an in-vehicle power supply system that includes an in-vehicle power supply device according to the second embodiment. [Figure 7] FIG. 7 is a circuit diagram that schematically shows an in-vehicle power supply system that includes an in-vehicle power supply device according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] In the following, embodiments of the present disclosure are listed and illustrated.

[0010] [1] An in-vehicle power supply device used in an in-vehicle power supply system including a battery, a capacitor, and a power path provided between the battery and the capacitor, Relay and a parallel circuit provided in parallel with the relay, the parallel circuit is configured by connecting a parallel relay and a resistor unit in series, A plurality of relay circuits each composed of the relay and the parallel circuit are provided in the power path between the battery and the capacitor. Automotive power supply device.

[0011] The above-mentioned automotive power supply device can perform precharging, which charges a capacitor while suppressing current, by utilizing a parallel circuit of one of the relay circuits. The above-mentioned automotive power supply device can suppress inrush current flow through the relay by switching the relay of the relay circuit to the ON state after precharging. Furthermore, the above-mentioned automotive power supply device can selectively use one of the relays in the multiple relay circuits as the relay to be switched to the ON state after precharging, which makes it easier to extend the life of devices including relays.

[0012] [2] A control unit is provided to control a plurality of the relay circuits, The plurality of relay circuits are arranged in series with each other in the power path, The control unit When a start condition for starting charging / discharging of the battery is satisfied, a first control is executed to control the parallel relay of the relay circuit to be switched among the plurality of relay circuits to an on state and to control the relay of the relay circuit that is not to be switched to an on state; When a switching condition is satisfied during execution of the first control, a second control is executed to switch the relay of the relay circuit to be switched to an on state. The in-vehicle power supply device according to [1].

[0013] The above-mentioned in-vehicle power supply device, in a configuration in which a plurality of relay circuits are connected in series, can perform precharging by executing a first control, and can suppress inrush current flowing through the relays by executing a second control after precharging.

[0014] [3] A control unit is provided to control a plurality of the relay circuits, The plurality of relay circuits are provided in parallel with each other in the power path, When a start condition for starting charging / discharging of the battery is satisfied, the control unit controls the parallel relays of at least some of the relay circuits to an on state, and then switches the relays of the relay circuits to be switched among the plurality of relay circuits to an on state. The in-vehicle power supply device according to [1].

[0015] In the above-described in-vehicle power supply device, in a configuration in which a plurality of relay circuits are provided in parallel, precharging can be performed by controlling at least some of the parallel relays to be in the ON state, and the above-described in-vehicle power supply device can suppress inrush current flowing through the relays by switching the relays of the relay circuits to be switched to the ON state after precharging.

[0016] [4] The control unit compares the deterioration levels of the relays and selects the relay circuit to be switched based on the comparison results. The in-vehicle power supply device according to [2] or [3].

[0017] The above-described in-vehicle power supply device can reflect the comparison result of the deterioration degree of the relay in the selection of the relay circuit to be switched.

[0018] [5] The control unit selects the relay circuit having the relay with the smallest degree of deterioration as the relay circuit to be switched. The in-vehicle power supply device according to [4].

[0019] In the above-described on-board power supply device, each relay is likely to deteriorate evenly, so that it is possible to more reliably achieve a long life for the device including the relays.

[0020] [6] The control unit specifies a resistance value of each of the relays when it is in an on state as the deterioration degree. The in-vehicle power supply device according to [4] or [5].

[0021] The above-described in-vehicle power supply device can use the resistance value of each relay when it is in the on state as the degree of deterioration.

[0022] [7] The control unit selects the relay circuit to be switched in accordance with a predetermined order. The in-vehicle power supply device according to [2] or [3].

[0023] The above-described in-vehicle power supply device selects the relay circuit to be switched in a predetermined order, and therefore each relay is likely to deteriorate evenly.

[0024] [8] The power path includes a positive power line provided between the positive electrode of the battery and one end of the capacitor, and a negative power line provided between the negative electrode of the battery and the other end of the capacitor, The plurality of relay circuits include the relay circuit provided on the positive power line and the relay circuit provided on the negative power line. [2], [4] to [7], the in-vehicle power supply device described in any one of [4] to [7].

[0025] In the above-described in-vehicle power supply device, a relay can be provided on each of the positive and negative power lines, and a plurality of relay circuits can be configured using the relays provided on each.

[0026] First Embodiment 1. Configuration of in-vehicle power supply system 100 FIG. 1 shows an in-vehicle power supply system 100 equipped with an in-vehicle power supply device 10. The in-vehicle power supply system 100 is used in a vehicle (not shown). The vehicle may be an electric vehicle, an engine vehicle, or a hybrid vehicle. In addition to the in-vehicle power supply device 10, the in-vehicle power supply system 100 also includes a battery 20, a power path 21, and a capacitor 22.

[0027] The battery 20 may be a lithium ion battery, a lead battery, or any other battery.

[0028] The power path 21 is an electrical path through which power is supplied from the battery 20. The power path 21 is provided between the battery 20 and the capacitor 22. The power path 21 has a positive power line 30 and a negative power line 31. The positive power line 30 is provided between the positive electrode of the battery 20 and one end of the capacitor 22. The positive terminal of the battery 20 is electrically connected to the positive power line 30. The negative power line 31 is provided between the negative electrode of the battery 20 and the other end of the capacitor 22. The negative terminal of the battery 20 is electrically connected to the negative power line 31. The negative terminal of the battery 20 is electrically connected to the ground. The output voltage of the battery 20 is applied to the power path 21 (more specifically, the positive power line 30). In this specification, unless otherwise specified, voltage refers to a potential difference with respect to the ground potential.

[0029] The capacitor 22 is electrically connected to the power path 21. The capacitor 22 is provided between the positive power line 30 and the negative power line 31. One end of the capacitor 22 is electrically connected to the positive power line 30. The other end of the capacitor 22 is electrically connected to the negative power line 31. Power based on the battery 20 is supplied to the capacitor 22 via the power path 21. The capacitor 22 smoothes the voltage applied to the power path 21 based on the battery 20.

[0030] In this embodiment, the capacitor 22 is configured as part of a drive unit 40 provided in the in-vehicle power supply system 100. In addition to the capacitor 22, the drive unit 40 includes an inverter 41 and a motor 42. The capacitor 22 is provided closer to the battery 20 than the inverter 41. The capacitor 22 smoothes the voltage based on the battery 20 and supplies it to the inverter 41. The inverter 41 is electrically connected to the power path 21. The inverter 41 generates an AC voltage (e.g., three-phase AC) from a DC voltage based on the voltage supplied from the battery 20 and supplies it to the motor 42. The motor 42 is, for example, a main motor. The motor 42 is a device that rotates based on the power supplied from the battery 20 and provides rotational force to the wheels of the vehicle.

[0031] The in-vehicle power supply device 10 is used in an in-vehicle power supply system 100. The in-vehicle power supply device 10 includes a plurality of relay circuits 50. The relay circuit 50 includes a relay 51 and a parallel circuit 52 that is provided in parallel with the relay 51. The relay 51 is a mechanical relay having contacts. The parallel circuit 52 is connected in parallel with the relay 51. The parallel circuit 52 is configured by connecting a parallel relay 53 and a resistor unit 54 in series. The parallel relay 53 may be a mechanical relay having contacts, or may be a relay that includes a semiconductor switch such as a field effect transistor (FET). The resistor unit 54 is configured, for example, by a known resistor.

[0032] The plurality of relay circuits 50 are provided in the power path 21 between the battery 20 and the capacitor 22. The plurality of relay circuits 50 are provided in series in the power path 21. The plurality of relay circuits 50 include a first relay circuit 50A provided in the positive power line 30 and a second relay circuit 50B provided in the negative power line 31.

[0033] The first relay circuit 50A includes a first relay 51A, which is an example of the relay 51, and a first parallel circuit 52A, which is an example of the parallel circuit 52. The first relay 51A is provided between the battery 20 (more specifically, the positive electrode of the battery 20) and the capacitor 22 (more specifically, one end of the capacitor 22). When the first relay 51A is in an ON state, it connects the battery 20 (more specifically, the positive electrode of the battery 20) and the capacitor 22 (more specifically, one end of the capacitor 22), and when the first relay 51A is in an OFF state, it disconnects the battery 20 (more specifically, the positive electrode of the battery 20) and the capacitor 22 (more specifically, one end of the capacitor 22). The first relay 51A is a system main relay. The first parallel circuit 52A is configured by connecting a first parallel relay 53A and a first resistor unit 54A in series. The first parallel relay 53A is an example of the parallel relay 53. The first resistor unit 54A is an example of the resistor unit 54.

[0034] The positive power line 30 includes a first positive power line 32 that is provided closer to the battery 20 than the first relay 51A, and a second positive power line 33 that is provided closer to the capacitor 22 than the first relay 51A. One end of the first positive power line 32 is electrically connected to a positive terminal of the battery 20. The other end of the first positive power line 32 is electrically connected to one end of the first relay 51A. One end of the second positive power line 33 is electrically connected to the other end of the first relay 51A. The other end of the second positive power line 33 is electrically connected to one end of the capacitor 22.

[0035] One end of the first relay 51A is electrically connected to the positive terminal of the battery 20 in a configuration in which it is shorted to the positive terminal of the battery 20. The other end of the first relay 51A is electrically connected to one end of the capacitor 22 in a configuration in which it is shorted to one end of the capacitor 22. When the first relay 51A is in an on state, the first positive side power line 32 and the second positive side power line 33 are electrically connected via the first relay 51A. When the first relay 51A is in an off state, the electrical continuity between the first positive side power line 32 and the second positive side power line 33 via the first relay 51A is released. One end of the first parallel circuit 52A is electrically connected to the first positive side power line 32 in a configuration in which it is shorted to the first positive side power line 32. In other words, one end of the first parallel circuit 52A is electrically connected to the positive terminal of the battery 20 and one end of the first relay 51A in a configuration in which it is shorted to the positive terminal of the battery 20 and one end of the first relay 51A. The other end of the first parallel circuit 52A is electrically connected to the second positive power line 33 in a configuration in which it is short-circuited to the second positive power line 33. In other words, the other end of the first parallel circuit 52A is electrically connected to the other end of the first relay 51A and one end of the capacitor 22 in a configuration in which it is short-circuited to the other end of the first relay 51A and one end of the capacitor 22.

[0036] The second relay circuit 50B includes a second relay 51B, which is an example of the relay 51, and a second parallel circuit 52B, which is an example of the parallel circuit 52. The second relay 51B is provided between the battery 20 (more specifically, the negative electrode of the battery 20) and the capacitor 22 (more specifically, the other end of the capacitor 22). When the second relay 51B is in an ON state, it connects the battery 20 (more specifically, the negative electrode of the battery 20) and the capacitor 22 (more specifically, the other end of the capacitor 22), and when the second relay 51B is in an OFF state, it disconnects the battery 20 (more specifically, the negative electrode of the battery 20) and the capacitor 22 (more specifically, the other end of the capacitor 22). The second relay 51B is a system main relay. The second parallel circuit 52B is configured by connecting a second parallel relay 53B and a second resistor 54B in series. The second parallel relay 53B is an example of the parallel relay 53. The second resistor section 54B corresponds to an example of the resistor section 54.

[0037] The negative power line 31 includes a first negative power line 34 that is provided closer to the battery 20 than the second relay 51B, and a second negative power line 35 that is provided closer to the capacitor 22 than the second relay 51B. One end of the first negative power line 34 is electrically connected to the negative terminal of the battery 20. First negative power line 34 The other end of the second negative electrode side power line 35 is electrically connected to one end of the second relay 51B. The other end of the second negative electrode side power line 35 is electrically connected to the other end of the capacitor 22.

[0038] One end of the second relay 51B is electrically connected to the negative terminal of the battery 20 in a configuration where it is shorted to the negative terminal of the battery 20. The other end of the second relay 51B is electrically connected to the other end of the capacitor 22 in a configuration where it is shorted to the other end of the capacitor 22. When the second relay 51B is in an on state, the first negative power line 34 and the second negative power line 35 are electrically connected via the second relay 51B. When the second relay 51B is in an off state, the electrical connection between the first negative power line 34 and the second negative power line 35 via the second relay 51B is released. One end of the second parallel circuit 52B is electrically connected to the first negative power line 34 in a configuration where it is shorted to the first negative power line 34. That is, one end of the second parallel circuit 52B is electrically connected to the negative terminal of the battery 20 and one end of the second relay 51B in a configuration where it is shorted to the negative terminal of the battery 20 and one end of the second relay 51B. The other end of the second parallel circuit 52B is electrically connected to the second negative-side power line 35 in a configuration in which it is short-circuited to the second negative-side power line 35. In other words, the other end of the second parallel circuit 52B is electrically connected to the other end of the second relay 51B and the other end of the capacitor 22 in a configuration in which it is short-circuited to the other end of the second relay 51B and the other end of the capacitor 22.

[0039] 2. Configuration of the control unit 71 The in-vehicle power supply device 10 includes a control unit 71 , a current detection unit 72 , a voltage detection unit 74 , a capacitor voltage detection unit 76 , and a temperature detection unit 77 .

[0040] The control unit 71 includes a control circuit such as an integrated circuit, etc. The control unit 71 includes a processing unit such as a CPU, a storage unit such as a memory, an input / output unit, etc.

[0041] The current detection unit 72 is configured as, for example, a known current sensor. The current detection unit 72 detects the value of the current flowing through the power path 21. The current detection unit 72 detects the value of the current flowing through the path of the power path 21 excluding the relay circuit 50. The current detection unit 72 detects the value of the current flowing through the first parallel circuit 52A when the first parallel relay 53A is in the ON state and the second relay 51B is in the ON state. The current detection unit 72 also detects the value of the current flowing through the second parallel circuit 52B when the second parallel relay 53B is in the ON state and the first relay 51A is in the ON state. The current detection unit 72 outputs a signal that can identify the detected value. The control unit 71 identifies the value of the current flowing through the power path 21 (more specifically, the path of the power path 21 excluding the relay circuit 50) based on the output signal of the current detection unit 72. The control unit 71 identifies the value of the current flowing through the first parallel circuit 52A by identifying the detected value when the capacitor 22 is being charged using the first parallel circuit 52A. Furthermore, the control unit 71 determines the value of the current flowing through the second parallel circuit 52B by determining the detection value when the capacitor 22 is being charged using the second parallel circuit 52B.

[0042] The voltage detection unit 74 is configured as, for example, a known voltage detection circuit. A voltage detection unit 74 is provided individually for each relay 51 and detects the potential difference across the corresponding relay 51. The voltage detection unit 74 includes a first voltage detection unit 74A provided for the first relay 51A and a second voltage detection unit 74B provided for the second relay 51B. Each voltage detection unit 74 outputs a signal that can identify the detected value. The control unit 71 identifies the potential difference across each relay 51 based on the output signal of each voltage detection unit 74.

[0043] The capacitor voltage detection unit 76 is configured as, for example, a known voltage detection circuit. The capacitor voltage detection unit 76 detects the voltage of the capacitor 22. The capacitor voltage detection unit 76 outputs a signal that can identify the detected value. The control unit 71 identifies the voltage of the capacitor 22 based on the output signal of the capacitor voltage detection unit 76.

[0044] A temperature detection unit 77 is provided for each relay 51, and detects the temperature of the contacts of the corresponding relay 51 when it is in the ON state. The temperature detection unit 77 includes a first temperature detection unit 77A provided for the first relay 51A and a second temperature detection unit 77B provided for the second relay 51B. Each temperature detection unit 77 outputs a signal that can identify the detected value. The control unit 71 identifies the temperature of the contacts of each relay 51 when it is in the ON state based on the output signal of each temperature detection unit 77.

[0045] The control unit 71 controls the first relay circuit 50A and the second relay circuit 50B. That is, the control unit 71 controls the first relay 51A, the first parallel relay 53A, the second relay 51B, and the second parallel relay 53B.

[0046] The control unit 71 executes the first control when a start condition for starting charging / discharging of the battery 20 is met. The start condition is, for example, that the vehicle has been switched to a start state. The start state of the vehicle is, for example, that a start switch (e.g., an ignition switch, a power switch, etc.) has been switched to an on state. The control unit 71 identifies the on / off state of the start switch, for example, by acquiring an on / off signal indicating the on / off state of the start switch directly or via another control device.

[0047] When the start condition is satisfied, the first relay 51A, the first parallel relay 53A, the second relay 51B, and the second parallel relay 53B are in the OFF state. The first control is a control for charging the capacitor 22 while suppressing the current using any of the parallel circuits 52. The first control is a control for controlling the parallel relay 53 of the relay circuit 50 to be switched among the multiple relay circuits 50 to the ON state and controlling the relay 51 of the relay circuit 50 that is not the target of switching to the ON state. More specifically, the first control is a control for switching the parallel relay 53 of the relay circuit 50 to be switched among the multiple relay circuits 50 while maintaining the relay 51 in the OFF state, and for the relay circuit 50 that is not the target of switching, while maintaining the parallel relay 53 in the OFF state, switching the relay 51 of the relay circuit 50 that is not the target of switching to the ON state. By executing the first control, the capacitor 22 is charged while suppressing the current using the resistor unit 54, and the voltage of the capacitor 22 gradually increases. As the voltage of the capacitor 22 increases, the difference between the voltage of the capacitor 22 and the voltage of the battery 20 decreases. As a result, the potential difference across the relay 51 of the relay circuit 50 to be switched becomes smaller.

[0048] The control unit 71 executes the second control when a switching condition is met during execution of the first control. The second control is control for switching the relay 51 of the relay circuit 50 to be switched to the ON state. The second control is control for maintaining the relay 51 of the relay circuit 50 that is not the switching target and maintaining the parallel relay 53 in the OFF state, and for the relay circuit 50 to be switched to the ON state and the parallel relay 53 in the relay circuit 50 to be switched to the OFF state. It is preferable that the timing for switching the parallel relay 53 to the OFF state is later than the timing for switching the relay 51 to the ON state. By executing the second control, more power is supplied from the battery 20 side to the capacitor 22 side.

[0049] The switching condition may be that the potential difference across the relay 51 of the relay circuit 50 to be switched becomes equal to or less than a predetermined value, that the value of the current flowing through the parallel relay 53 of the relay circuit 50 to be switched becomes equal to or less than a predetermined value, that a predetermined time has elapsed since the start of the first control, that the voltage of the capacitor 22 becomes equal to or greater than a predetermined value, or any other condition.

[0050] When the relay circuit 50 to be switched is the first relay circuit 50A, the control unit 71 executes the first control and the second control as follows. In the first control, the control unit 71 controls the first parallel relay 53A of the first relay circuit 50A to the ON state and the second relay 51B of the second relay circuit 50B to the ON state. More specifically, the control unit 71 switches the first parallel relay 53A to the ON state while maintaining the first relay 51A in the OFF state, and switches the second relay 51B to the ON state while maintaining the second parallel relay 53B in the OFF state. As a result, as shown in FIG. 2 , the current from the battery 20 is suppressed by the first resistor 54A and supplied to the capacitor 22. The control unit 71 executes the second control when a switching condition is met during the execution of the first control. In the second control, the control unit 71 switches the first relay 51A of the first relay circuit 50A to the ON state. More specifically, the control unit 71 switches the first relay 51A to the ON state and switches the first parallel relay 53A to the OFF state while maintaining the second relay 51B in the ON state and the second parallel relay 53B in the OFF state. As a result, as shown in Fig. 3, the first relay 51A can be switched to the ON state while suppressing the inrush current to the first relay 51A. As a result, a larger amount of power is supplied from the battery 20 side to the capacitor 22 side.

[0051] When the relay circuit 50 to be switched is the second relay circuit 50B, the control unit 71 executes the first control and the second control as follows. In the first control, the control unit 71 controls the second parallel relay 53B of the second relay circuit 50B to the ON state and the first relay 51A of the first relay circuit 50A to the ON state. More specifically, the control unit 71 switches the second parallel relay 53B to the ON state while maintaining the second relay 51B in the OFF state, and switches the first relay 51A to the ON state while maintaining the first parallel relay 53A in the OFF state. As a result, as shown in FIG. 4 , the current from the battery 20 is suppressed by the second resistor 54B and supplied to the capacitor 22. The control unit 71 executes the second control when a switching condition is met during the execution of the first control. In the second control, the control unit 71 switches the second relay 51B of the second relay circuit 50B to the ON state. More specifically, the control unit 71 switches the second relay 51B to the ON state and switches the second parallel relay 53B to the OFF state while maintaining the first relay 51A in the ON state and the first parallel relay 53A in the OFF state. This makes it possible to switch the second relay 51B to the ON state while suppressing the inrush current to the second relay 51B. As a result, a larger amount of power is supplied from the battery 20 side to the capacitor 22 side.

[0052] The control unit 71 compares the deterioration levels of the relays 51 and selects the relay circuit 50 to be switched based on the comparison results. The control unit 71 selects the relay circuit 50 having the relay 51 with the smallest deterioration level as the relay circuit 50 to be switched.

[0053] 3. Degree of deterioration The deterioration level of the relay 51 is determined based on, for example, the potential difference across the relay 51 when the relay 51 is in the on state, the resistance value when the relay 51 is in the on state, the number of times the relay 51 operates, the temperature when the relay 51 is in the on state (more specifically, the temperature of the relay contacts), a combination of a plurality of these, etc. The deterioration level of the relay 51 may be these values ​​themselves, or may be a value obtained by substituting these values ​​into an arithmetic expression.

[0054] The degree of deterioration of the relay 51 increases as the potential difference between both ends of the relay 51 increases. The degree of deterioration of the relay 51 increases as the resistance value of the relay 51 when it is in the on state increases. The degree of deterioration of the relay 51 increases as the number of times the relay 51 operates increases. The degree of deterioration of the relay 51 increases as the temperature of the relay 51 when it is in the on state increases, assuming that the value of the current flowing through the relay 51 is constant.

[0055] As a method of determining the potential difference between both ends of the relay 51, the control unit 71 determines the potential difference between both ends of the first relay 51A and the second relay 51B, for example, while the second control is being executed (i.e., when the first relay 51A and the second relay 51B are in the on state).

[0056] As a method of specifying the resistance value of the relay 51 when it is in the on state, the control unit 71 specifies the potential difference between both ends of the first relay 51A and the second relay 51B and the value of the current flowing through the power path 21 while the second control is being executed (that is, when the first relay 51A and the second relay 51B are in the on state), for example. Then, the control unit 71 specifies the resistance value of each relay 51 based on the specified potential difference and current value. Note that "while the second control is being executed" refers to after the first control is executed and the vehicle has switched to the starting state.

[0057] As a method of identifying the number of times that the relay 51 is operated, the control unit 71 counts, for each relay 51, the number of times that the relay 51 is switched to the on state in the second control, for example.

[0058] As a method of determining the temperature of the contacts when the relays 51 are in the on state, the control unit 71 determines the temperature of the contacts when each relay 51 is in the on state based on the output signal of the temperature detection unit 77, for example, while the second control is being executed (i.e., when the first relay 51A and the second relay 51B are in the on state).

[0059] 4. Operation of the Vehicle Power Supply Device 10 5, for example, when the control circuit constituting the control unit 71 is started. In step S101, the control unit 71 determines whether a start condition for starting charging / discharging of the battery 20 is met. If the start condition is not met (No in step S101), the control unit 71 repeats the process of step S101 until the start condition is met. If the start condition is met (Yes in step S101), the control unit 71 selects the relay circuit 50 to be switched in step S102.

[0060] The control unit 71 selects the relay circuit 50 to be switched based on the deterioration level of the relay 51 identified in the previous process of step S106. That is, the control unit 71 selects the relay circuit 50 to be switched based on the deterioration level of the relay 51 identified during the previous execution of the second control. When the control unit 71 first selects the relay circuit 50 to be switched, it selects a predetermined relay circuit 50 as the relay circuit 50 to be switched.

[0061] After selecting the relay circuit 50 to be switched, the control unit 71 starts the first control described above in step S103. After starting the first control, the control unit 71 determines whether the switching condition described above is met in step S104. If the control unit 71 determines that the switching condition is not met (No in step S104), it repeats the processing of step S104 until the switching condition is met. If the control unit 71 determines that the switching condition is met (Yes in step S104), it starts the second control described above in step S105.

[0062] After starting the second control, the control unit 71 identifies the deterioration level of each relay 51 in step S106. After identifying the deterioration level of each relay 51, the control unit 71 determines whether or not a termination condition is met in step S107. The termination condition is, for example, a condition for terminating charging and discharging of the battery 20. If the control unit 71 determines that the termination condition is not met (No in step S107), the control unit 71 repeats the process of step S107 until the termination condition is met. If the control unit 71 determines that the termination condition is met (Yes in step S107), the control unit 71 performs termination processing in step S108. The termination processing is, for example, processing for controlling all of the relays and parallel relays (in this embodiment, all of the first relay 51A, the first parallel relay 53A, the second relay 51B, and the second parallel relay 53B) to the OFF state. After the termination processing, the control unit 71 returns to the process of step S101.

[0063] 5.Example of effects The in-vehicle power supply device 10 can perform pre-charging, which charges the capacitor 22 while suppressing current, by utilizing the parallel circuit 52 of one of the relay circuits 50. The in-vehicle power supply device 10 can suppress inrush current from flowing through the relay 51 by switching the relay 51 of the relay circuit 50 to be switched on after pre-charging. Moreover, the in-vehicle power supply device 10 can selectively use the relay 51 of each of the multiple relay circuits 50 to switch on after pre-charging, which makes it easy to extend the life of the device including the relay 51.

[0064] In a configuration in which a plurality of relay circuits 50 are connected in series, the in-vehicle power supply device 10 can perform pre-charging to charge the capacitor 22 while suppressing current by executing the first control. Then, the in-vehicle power supply device 10 can suppress inrush current from flowing to the relay 51 by executing the second control after pre-charging.

[0065] The in-vehicle power supply device 10 can reflect the comparison result of the deterioration degree of the relay 51 in the selection of the relay circuit 50 to be switched.

[0066] In the in-vehicle power supply device 10, each relay 51 is likely to deteriorate evenly, so that the life of the device including the relay 51 can be more reliably extended.

[0067] The in-vehicle power supply device 10 can use the resistance value of each relay 51 when it is in the on state as the degree of deterioration.

[0068] The vehicle power supply device 10 can be provided with a relay 51 on each of the positive power line 30 and the negative power line 31, and multiple relay circuits 50 can be configured using the relays 51 provided on each.

[0069] Second Embodiment In the second embodiment, an example will be described in which a plurality of relay circuits 50 are provided in series in the positive power line 30. Note that the same components as those in the first embodiment are given the same reference numerals, and detailed description thereof will be omitted.

[0070] 6 shows an in-vehicle power supply system 200 including an in-vehicle power supply device 210 of the second embodiment. In addition to the in-vehicle power supply device 210, the in-vehicle power supply system 200 includes a battery 20, a power path 21, and a capacitor 22. The in-vehicle power supply device 210 includes multiple relay circuits 50, a third relay 60, a control unit 71, a current detection unit 72, a voltage detection unit 74, a capacitor voltage detection unit 76, and a temperature detection unit 77. The multiple relay circuits 50 are connected in series to one another on the positive power line 30.

[0071] The third relay 60 is provided on the negative power line 31. The third relay 60 is a system main relay. The third relay 60 is a mechanical relay having contacts. The third relay 60 is controlled by the control unit 71.

[0072] The control unit 71 performs the processing of Fig. 5 described in the first embodiment. However, the second embodiment differs in that when the control unit 71 executes the first control in step S103, in addition to the operations described in the first embodiment, the control unit 71 switches the third relay 60 to the ON state. Also, when the control unit 71 executes the termination processing in step S108, in addition to the operations described in the first embodiment, the control unit 71 switches the third relay 60 to the OFF state. In other respects, the operation of the control unit 71 is the same as the operation of the control unit 71 in the first embodiment.

[0073] The in-vehicle power supply device 210 of the second embodiment can also perform pre-charging, which charges the capacitor 22 while suppressing current, by utilizing the parallel circuit 52 of any of the relay circuits 50. The in-vehicle power supply device 210 can suppress inrush current from flowing to the relay 51 by switching the relay 51 of that relay circuit 50 to the ON state after pre-charging. Moreover, the in-vehicle power supply device 210 can selectively use the relay 51 of the multiple relay circuits 50 to switch to the ON state after pre-charging, which makes it easy to extend the life of the device including the relay 51.

[0074] <Third embodiment> In the third embodiment, an example will be described in which a plurality of relay circuits 50 are provided in parallel with one another on the power path 21. Note that the same components as those in the first embodiment are given the same reference numerals, and detailed description thereof will be omitted.

[0075] 7 shows an in-vehicle power supply system 300 including an in-vehicle power supply device 310 of the third embodiment. In addition to the in-vehicle power supply device 310, the in-vehicle power supply system 300 includes a battery 20, a power path 21, and a capacitor 22. The in-vehicle power supply device 310 includes multiple relay circuits 50, a third relay 60, a control unit 71, a current detection unit 72, a voltage detection unit 74, a capacitor voltage detection unit 76, and a temperature detection unit 77. The multiple relay circuits 50 are provided in parallel with each other on the positive power line 30.

[0076] The third relay 60 is provided on the negative power line 31. The third relay 60 is a system main relay. The third relay 60 is a mechanical relay having contacts. The third relay 60 is controlled by the control unit 71.

[0077] When a start condition for starting charging / discharging of the battery 20 is met, the control unit 71 controls the parallel relays 53 of at least some of the multiple relay circuits 50 to the ON state. The control unit 71 also controls the third relay 60 to the ON state. As a result, power is supplied from the battery 20 to the capacitor 22 via one of the parallel circuits 52. In other words, the capacitor 22 is charged with the current suppressed by the resistor unit 54. Thereafter, the control unit 71 switches the relay 51 of the relay circuit 50 to be switched among the multiple relay circuits 50 to the ON state. As a result, a larger current is supplied from the battery 20 to the capacitor 22.

[0078] The control unit 71 performs, for example, the processing of Fig. 5 described in the first embodiment. However, when executing the first control in step S103, the control unit 71 switches the parallel relays 53 of at least some of the relay circuits 50 to the ON state regardless of whether they are subject to switching, and switches the third relay 60 to the ON state. Furthermore, when executing the termination processing in step S108, the control unit 71 switches the third relay 60 to the OFF state in addition to the operations described in the first embodiment. In other respects, the operation of the control unit 71 is the same as the operation of the control unit 71 in the first embodiment.

[0079] In a configuration in which a plurality of relay circuits 50 are provided in parallel, the in-vehicle power supply device 310 of the third embodiment controls at least some of the parallel relays 53 to the on state, thereby enabling pre-charging to charge the capacitor 22 while suppressing current. Then, after pre-charging, the in-vehicle power supply device 310 switches the relay 51 of the relay circuit 50 to be switched to the on state, thereby preventing inrush current from flowing through the relay 51.

[0080] <Fourth embodiment> In the fourth embodiment, an example will be described in which the relay circuit 50 to be switched is selected in a predetermined order. Note that the automotive power supply system of the fourth embodiment has the same configuration as that of Fig. 1 described in the first embodiment, and therefore will be described with reference to Fig. 1.

[0081] In the fourth embodiment, the control unit 71 selects the relay circuit 50 to be switched in a predetermined order. For example, the control unit 71 may select the relay circuit 50 to be switched in the order of the first relay circuit 50A and the second relay circuit 50B. The control unit 71 performs, for example, the process shown in FIG. 5 described in the first embodiment. The control unit 71 may switch the relay circuit 50 to be switched in a predetermined order every time, or may switch in a predetermined order each time a predetermined condition is met. The predetermined condition may be, for example, that the relay 51 of the relay circuit 50 to be switched has been switched to the on state a predetermined number of times in succession, that the degree of deterioration of the relay 51 of the relay circuit 50 to be switched exceeds a threshold, or another condition.

[0082] The in-vehicle power supply device 10 of the fourth embodiment selects the relay circuit 50 to be switched in accordance with a predetermined order, and therefore each relay 51 is likely to deteriorate evenly.

[0083] <Other embodiments> The present disclosure is not limited to the embodiments described above and in the drawings. For example, any combination of features of the above-described or following embodiments is possible within a range that does not contradict. Furthermore, any feature of the above-described or following embodiments may be omitted unless explicitly stated as essential. Furthermore, the above-described embodiment may be modified as follows.

[0084] In each of the above embodiments, the number of relay circuits 50 is two, but it may be three or more.

[0085] In the second embodiment, the plurality of relay circuits 50 are arranged in series on the positive power line 30, but may be arranged in series on the negative power line 31.

[0086] In the third embodiment, the plurality of relay circuits 50 are arranged in parallel on the positive power line 30, but may be arranged in parallel on the negative power line 31.

[0087] It should be noted that the embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, and is intended to include all modifications within the scope indicated by the claims or within the scope equivalent to the claims. [Explanation of symbols]

[0088] 10…Vehicle power supply unit 20...Battery 21…Power line 22...Capacitor 30...Positive power line 31...Negative power line 32...First positive power line 33...Second positive power line 34...First negative power line 35...Second negative power line 40...Drive unit 41...Inverter 42...Motor 50...Relay circuit 50A...1st relay circuit 50B...Second relay circuit 51...Relay 51A...1st relay 51B...Second relay 52...Parallel circuit 52A…1st parallel circuit 52B…Second parallel circuit 53...Parallel relay 53A...1st parallel relay 53B...Second parallel relay 54...Resistance part 54A...1st resistance section 54B…Second resistance section 60...3rd relay 71...Control unit 72...Current detection section 74...Voltage detection unit 74A...First voltage detection unit 74B...Second voltage detection unit 76...Capacitor voltage detection section 77...Temperature detection unit 77A...First temperature detection unit 77B...Second temperature detection unit 100...Automotive power supply system 200...Automotive power supply system 210…Vehicle power supply unit 300...Automotive power supply system 310...Automotive power supply unit

Claims

1. An in-vehicle power supply device for use in an in-vehicle power supply system including a battery, a capacitor, and a power path provided between the battery and the capacitor, Relay and a parallel circuit provided in parallel with the relay, the parallel circuit is configured by connecting a parallel relay and a resistor unit in series, a plurality of relay circuits each including the relay and the parallel circuit are provided in the power path between the battery and the capacitor; Further, a control unit for controlling the plurality of relay circuits is provided, The plurality of relay circuits are arranged in series with each other in the power path, The control unit When a start condition for starting charging / discharging of the battery is satisfied, a first control is executed to control the parallel relay of the relay circuit to be switched among the plurality of relay circuits to an ON state and to control the relay of the relay circuit that is not to be switched to an ON state; When a switching condition is satisfied during execution of the first control, a second control is executed to switch the relay of the relay circuit to be switched to an on state; Furthermore, the control unit compares the deterioration levels of the relays and selects the relay circuit to be switched based on the comparison result. Automotive power supply device.

2. An in-vehicle power supply device for use in an in-vehicle power supply system including a battery, a capacitor, and a power path provided between the battery and the capacitor, Relay and a parallel circuit provided in parallel with the relay, the parallel circuit is configured by connecting a parallel relay and a resistor unit in series, a plurality of relay circuits each including the relay and the parallel circuit are provided in the power path between the battery and the capacitor; a control unit for controlling the plurality of relay circuits; The plurality of relay circuits are provided in parallel with each other in the power path, the control unit controls the parallel relays of at least some of the relay circuits to an on state when a start condition for starting charging / discharging of the battery is satisfied, and then switches the relays of the relay circuits to be switched among the plurality of relay circuits to an on state; Furthermore, the control unit compares the deterioration levels of the relays and selects the relay circuit to be switched based on the comparison result. Automotive power supply device.

3. The control unit selects the relay circuit having the relay with the smallest degree of deterioration as the relay circuit to be switched.

3. The in-vehicle power supply device according to claim 1 or 2.

4. The control unit specifies a resistance value of each of the relays in an on state as the deterioration degree.

4. The vehicle-mounted power supply device according to claim 3.

5. An in-vehicle power supply device for use in an in-vehicle power supply system including a battery, a capacitor, and a power path provided between the battery and the capacitor, Relay and a parallel circuit provided in parallel with the relay, the parallel circuit is configured by connecting a parallel relay and a resistor unit in series, a plurality of relay circuits each including the relay and the parallel circuit are provided in the power path between the battery and the capacitor; Further, a control unit for controlling the plurality of relay circuits is provided, The plurality of relay circuits are arranged in series with each other in the power path, The control unit When a start condition for starting charging / discharging of the battery is satisfied, a first control is executed to control the parallel relay of the relay circuit to be switched among the plurality of relay circuits to an ON state and to control the relay of the relay circuit that is not to be switched to an ON state; When a switching condition is satisfied during execution of the first control, a second control is executed to switch the relay of the relay circuit to be switched to an on state; Furthermore, the control unit selects the relay circuit to be switched in accordance with a predetermined order. Automotive power supply device.

6. An in-vehicle power supply device for use in an in-vehicle power supply system including a battery, a capacitor, and a power path provided between the battery and the capacitor, Relay and a parallel circuit provided in parallel with the relay, the parallel circuit is configured by connecting a parallel relay and a resistor unit in series, a plurality of relay circuits each including the relay and the parallel circuit are provided in the power path between the battery and the capacitor; a control unit for controlling the plurality of relay circuits; The plurality of relay circuits are provided in parallel with each other in the power path, the control unit controls the parallel relays of at least some of the relay circuits to an on state when a start condition for starting charging / discharging of the battery is satisfied, and then switches the relays of the relay circuits to be switched among the plurality of relay circuits to an on state; Furthermore, the control unit selects the relay circuit to be switched in accordance with a predetermined order. Automotive power supply device.

7. the power path includes a positive power line provided between a positive electrode of the battery and one end of the capacitor, and a negative power line provided between a negative electrode of the battery and the other end of the capacitor; The plurality of relay circuits include the relay circuit provided on the positive power line and the relay circuit provided on the negative power line.

6. The in-vehicle power supply device according to claim 1 or 5.

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