Deterioration diagnosis device and deterioration diagnosis method

Abstract

To provide a deterioration diagnosis device and a deterioration diagnostic method which appropriately perform deterioration determination of an electric double layer capacitor in an electrical power system.SOLUTION: A deterioration diagnosis device (management device 14) which determines deterioration of an electric double layer capacitor 12 mounted on a vehicle system (an electrical power system) 1 includes a changeover section and a determination section. When the electrical power system is stopped, the changeover section stops power supply from an electric source to a load and supplies electric power corresponding to consumption power in backup operation from the electric double layer capacitor. When the electrical power system is stopped, the determination section determines deterioration of the electric double layer capacitor based on power supply state of the electric double layer capacitor when a predetermined lapse condition is satisfied after the power supply state by the electric double layer capacitor starts.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The disclosed embodiments relate to a degradation diagnosis device and a degradation diagnosis method. [Background technology]

[0002] BACKGROUND ART A power supply system for a vehicle having an electric double layer capacitor is known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-23093 Summary of the Invention [Problem to be solved by the invention]

[0004] When an electric double layer capacitor is used as a backup power supply, it is desirable to diagnose the deterioration of the electric double layer capacitor so that power can be supplied from the electric double layer capacitor in the event of a power loss when power supply from the battery stops.

[0005] However, the above technique does not take into consideration the diagnosis of deterioration of the electric double layer capacitor, and there is room for improvement.

[0006] One aspect of the embodiment has been made in view of the above, and aims to provide a degradation diagnosis device and a degradation diagnosis method that appropriately perform degradation determination of an electric double layer capacitor in a power supply system. [Means for solving the problem]

[0007] A degradation diagnosis device according to one aspect of the embodiment determines degradation of an electric double layer capacitor mounted on a power supply system. The degradation diagnosis device includes a switching unit and a determination unit. When the power supply system is shut down, the switching unit stops the power supply from the power source to the load and causes the electric double layer capacitor to supply power corresponding to the power consumption during backup processing. When the power supply system is shut down, the determination unit determines degradation of the electric double layer capacitor based on the power supply state of the electric double layer capacitor when a predetermined elapsed condition is satisfied after the start of power supply by the electric double layer capacitor. [Effects of the Invention]

[0008] A degradation diagnosis device and a degradation diagnosis method according to an aspect of the embodiment can appropriately determine the degradation of an electric double layer capacitor in a power supply system. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is an explanatory diagram illustrating an example of the configuration of a vehicle system according to an embodiment. [Figure 2] FIG. 2 is a block diagram illustrating a management device according to the embodiment. [Figure 3] FIG. 3 is a diagram showing a supply path of power supplied from the EDLC when the operating state of the primary power supply is switched from the ON state to the OFF state. [Figure 4] FIG. 4 is a diagram showing a supply path of power supplied to a load or the like after the voltage of the EDLC becomes equal to or lower than a predetermined voltage. [Figure 5] FIG. 5 is a flowchart illustrating a degradation diagnosis process for an EDLC according to an embodiment. [Figure 6] FIG. 6 is a time chart illustrating the deterioration diagnosis of the EDLC. [Figure 7] FIG. 7 is an explanatory diagram showing an example of the configuration of a vehicle system according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of a degradation diagnosis device and a degradation diagnosis method will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following embodiments. In the following, a vehicle system will be described as an example of a power supply system, and a degradation diagnosis device mounted on the vehicle system will be described as an example.

[0011] Fig. 1 is an explanatory diagram showing an example of the configuration of a vehicle system 1 according to an embodiment. As shown in Fig. 1, the vehicle system 1 includes a vehicle battery 2 (power source), an on-board power supply device 3, a load 4, and a storage 5. The vehicle battery 2 includes, for example, a lead battery or a lithium-ion battery.

[0012] The load 4 includes a device that generates vehicle data to be stored in the storage 5 during backup processing when a vehicle accident or other event occurs and power is not supplied from the vehicle battery 2. The load 4 includes, for example, a drive recorder, a device that operates while driving such as a radar device, a vehicle speed sensor, etc.

[0013] The vehicle data stored in storage 5 includes, for example, image data captured by a camera at a predetermined storage time, including when power is lost. The vehicle data stored in storage 5 may also include vehicle driving data. The vehicle driving data includes data acquired by a vehicle speed sensor, etc. If the vehicle is capable of autonomous driving, the vehicle driving data includes data during autonomous driving.

[0014] The storage 5 includes a semiconductor memory element such as a flash memory, a hard disk, etc. The storage 5 stores vehicle data, for example, in the event of a loss of power due to a vehicle accident or the like.

[0015] The vehicle-mounted power supply device 3 includes a primary power supply 10, a secondary power supply 11, an electric double-layer capacitor (hereinafter referred to as an EDLC (Electric Double-Layer Capacitor)) 12, a charge / discharge circuit 13, and a management device .

[0016] The primary power supply 10 is provided on the vehicle battery 2 side of the on-board power supply device 3. The primary power supply 10 is connected to the vehicle battery 2 via a diode 15. The primary power supply 10 is connected to a secondary power supply 11. The primary power supply 10 is connected to an EDLC 12 via a charge / discharge circuit 13. The diode 15 prevents reverse current flow to the vehicle battery 2 side.

[0017] The primary power source 10 is, for example, a DC-DC converter. The primary power source 10 converts the power supplied from the vehicle battery 2 into a predetermined DC voltage to generate an intermediate voltage. The operating state of the primary power source 10 is changed based on an ON signal and an OFF signal transmitted from the management device 14.

[0018] When the OFF signal is transmitted, the operating state of the primary power source 10 is changed from the ON state to the OFF state. When the operating state is the OFF state, the primary power source 10 does not generate an intermediate voltage. In other words, when the OFF signal is transmitted, the primary power source 10 does not supply power to the secondary power source 11 side.

[0019] When the ON signal is transmitted, the operation state of the primary power source 10 is changed from the OFF state to the ON state. When the operation state is the ON state, the primary power source 10 generates an intermediate voltage and supplies power to the secondary power source 11 side.

[0020] The secondary power supply 11 is provided between the primary power supply 10 and the load 4, storage 5, and management device 14. The secondary power supply 11 is connected to the primary power supply 10. The secondary power supply 11 is connected to the EDLC 12 via a charge / discharge circuit 13. The secondary power supply 11 is connected to the load 4, storage 5, and management device 14. The secondary power supply 11 converts the intermediate voltage generated by the primary power supply 10 into an operating voltage for the load 4, storage 5, and management device 14. The secondary power supply 11 is, for example, a DC-DC converter.

[0021] The EDLC 12 is a backup power supply. The EDLC 12 is connected to the primary power supply 10 and the secondary power supply 11 via a charge / discharge circuit 13. The EDLC 12 supplies power to the load 4, the storage 5, and the management device 14 when the vehicle battery 2 loses power. When the vehicle system 1 is started, the EDLC 12 is supplied with power from the vehicle battery 2 and charged. The EDLC 12 is configured to supply enough power to the load 4 and the like to perform backup processing for storing vehicle data in the storage 5 when the vehicle battery 2 loses power.

[0022] The charge / discharge circuit 13 includes a circuit that prevents a large current from flowing when charging / discharging the EDLC 12. The charge / discharge circuit 13 includes, for example, a constant current circuit that sets the current supplied to the EDLC 12 to a predetermined current.

[0023] The management device 14 is a control device that controls the on-board power supply device 3. The management device 14 functions as a degradation diagnosis device that diagnoses the degradation of the EDLC 12. The management device 14 performs the degradation diagnosis of the EDLC 12 when the vehicle system 1 is stopped.

[0024] Next, the management device 14 will be described with reference to Fig. 2. Fig. 2 is a block diagram showing the management device 14 according to the embodiment. Here, a configuration that functions as a degradation diagnosis device will be described.

[0025] The management device 14 includes a storage unit 20 and a control unit 21. The storage unit 20 is realized by, for example, a semiconductor memory element such as a RAM (Random Access Memory) or a flash memory, or a storage device such as a hard disk or an optical disk.

[0026] The control unit 21 is a controller, and is realized by, for example, a CPU (Central Processing Unit), MPU (Micro Processing Unit), ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), etc., by executing various programs (corresponding to an example of an information processing program) stored in a storage device inside the management device 14 using a storage area such as RAM as a working area.

[0027] The control unit 21 includes an acquisition unit 22, a measurement unit 23, a determination unit 24, a switching unit 25, and a notification unit 26. The acquisition unit 22, the measurement unit 23, the determination unit 24, the switching unit 25, and the notification unit 26 are not limited to this, and may be configured as an integrated unit or may be configured as separate units.

[0028] The acquisition unit 22 acquires an ON signal and an OFF signal for the vehicle system 1 from the start switch 30. The start switch 30 is a switch that switches ON or OFF the power supply for the entire vehicle system 1. The start switch 30 may be an ignition switch.

[0029] The acquisition unit 22 acquires a signal related to voltage from the first voltage sensor 31. The first voltage sensor 31 detects the voltage input from the vehicle battery 2 to the in-vehicle power supply device 3. If a power loss occurs in the vehicle battery 2 while the start switch 30 is turned on, the voltage detected by the first voltage sensor 31 becomes a power loss voltage, for example, "0 V."

[0030] The acquisition unit 22 acquires a signal related to voltage from the second voltage sensor 32. The second voltage sensor 32 detects the voltage of the EDLC 12. The second voltage sensor 32 is provided between the EDLC 12 and the charge / discharge circuit 13.

[0031] The measurement unit 23 measures the time for which power is supplied from the EDLC 12 to the load 4 and the like when the start switch 30 is switched from ON to OFF and the primary power supply 10 is turned OFF. The measurement unit 23 measures the time for which power is supplied from the primary power supply 10 to the OFF state until the voltage of the EDLC 12 drops below a predetermined voltage. The predetermined voltage is a voltage that is set in advance. The predetermined voltage is higher than the voltage at which the shutdown process executed when the vehicle system 1 is stopped becomes inoperable.

[0032] The determination unit 24 determines whether the start switch 30 has been operated. Specifically, the determination unit 24 determines whether the signal obtained from the start switch 30 has changed from an OFF signal to an ON signal. The determination unit 24 also determines whether the signal obtained from the start switch 30 has changed from an ON signal to an OFF signal.

[0033] When the start switch 30 is ON, the determination unit 24 determines whether the voltage detected by the first voltage sensor 31 is equal to or lower than the power loss voltage.

[0034] When the vehicle system 1 is stopped, the determination unit 24 determines the degradation of the EDLC 12 based on the power supply state of the EDLC 12 when a predetermined elapsed condition is satisfied after the start of power supply by the EDLC 12. The predetermined elapsed condition is satisfied when the voltage of the EDLC 12 becomes equal to or lower than a predetermined voltage after the start of power supply by the EDLC 12. The power supply state includes the time for which power is supplied by the EDLC 12.

[0035] Specifically, when the start switch 30 is switched from ON to OFF and the primary power supply 10 is turned OFF, the determination unit 24 determines whether the power supply time until the voltage of the EDLC 12 becomes equal to or lower than a predetermined voltage is less than a predetermined time. If the power supply time until the voltage of the EDLC 12 becomes equal to or lower than the predetermined voltage is less than the predetermined time, the determination unit 24 determines that the EDLC 12 has deteriorated. If the power supply time until the voltage of the EDLC 12 becomes equal to or lower than the predetermined voltage is equal to or longer than the predetermined time, the determination unit 24 determines that the EDLC 12 has not deteriorated.

[0036] The predetermined time is a time that is set in advance and is a time during which backup processing can be performed when power loss occurs in the vehicle battery 2.

[0037] When the vehicle system 1 is stopped, the switching unit 25 stops the power supply from the vehicle battery 2 to the load 4 and the like, and causes the EDLC 12 to supply power to the load 4 and the like.

[0038] Specifically, when start switch 30 is switched from ON to OFF, switching unit 25 transmits an OFF signal to primary power source 10, controls primary power source 10, and switches the operation state of primary power source 10 from ON to OFF. When the operation state of primary power source 10 is switched from ON to OFF, power is supplied from EDLC 12 to load 4 and the like, as shown in FIG. 3. Then, a shutdown process of vehicle system 1 is performed using the power supplied from EDLC 12. The shutdown process includes a degradation diagnosis process for EDLC 12. FIG. 3 is a diagram showing the supply path of power supplied from EDLC 12 when the operation state of primary power source 10 is switched from ON to OFF.

[0039] In the degradation diagnosis process, the same process as that performed when the vehicle battery 2 loses power due to the load 4 or the like is performed. That is, in the degradation diagnosis process, the same process as that performed in the backup process is performed, and the power actually consumed in the backup process is consumed. In the degradation diagnosis process, the power supply from the vehicle battery 2 is cut off, and power is supplied from the EDLC 12 to the load 4 or the like, and vehicle data is stored in the storage 5.

[0040] When the start switch 30 is switched from ON to OFF to set the operation state of the primary power source 10 to the OFF state and the voltage of the EDLC 12 falls below a predetermined voltage, the switching unit 25 sends an ON signal to the primary power source 10 to control the primary power source 10. The switching unit 25 switches the operation state of the primary power source 10 from the OFF state to the ON state. When the operation state of the primary power source 10 is switched from the OFF state to the ON state, power is supplied from the vehicle battery 2 to the load 4 and the like, as shown in FIG. 4. Therefore, the shutdown process of the vehicle system 1 continues using the power supplied from the vehicle battery 2. FIG. 4 is a diagram showing the supply path of power supplied to the load 4 and the like after the voltage of the EDLC 12 falls below the predetermined voltage.

[0041] If the degradation of the EDLC 12 is determined when the vehicle system 1 was last stopped, the notification unit 26 notifies the degradation of the EDLC 12 when the vehicle system 1 is started. For example, the notification unit 26 turns on a warning light on the instrument panel to indicate that the EDLC 12 is degraded.

[0042] Next, the degradation diagnosis process for the EDLC 12 according to the embodiment will be described with reference to Fig. 5. Fig. 5 is a flowchart illustrating the degradation diagnosis process for the EDLC 12 according to the embodiment.

[0043] The management device 14 determines whether the start switch 30 has been turned OFF (S100). If the start switch 30 is ON (S100: No), the management device 14 ends the current process.

[0044] If the start switch 30 is OFF (S100: Yes), the management device 14 switches the operation state of the primary power supply 10 to the OFF state (S101). As a result, power is supplied from the EDLC 12 to the load 4, the storage 5, and the management device 14 via the charge / discharge circuit 13 and the secondary power supply 11.

[0045] The management device 14 measures the time for which power is supplied from the EDLC 12 to the load 4, etc. (S102). The management device 14 determines whether the voltage of the EDLC 12 is equal to or lower than a predetermined voltage (S103). If the voltage of the EDLC 12 is higher than the predetermined voltage (S103: No), the management device 14 returns to step S102 and continues measuring the time for which power is supplied.

[0046] If the voltage of the EDLC 12 is equal to or lower than the predetermined voltage (S103: Yes), the management device 14 determines whether the power supply time is less than the predetermined time (S104). That is, the management device 14 determines whether the power supply time when the voltage of the EDLC 12 is equal to or lower than the predetermined voltage is less than the predetermined time.

[0047] If the power supply time is less than the predetermined time (S104: Yes), the management device 14 determines that the EDLC 12 has deteriorated (S105).

[0048] If the power supply time is equal to or longer than the predetermined time (S104: No), the management device 14 determines that the EDLC 12 is not deteriorated (S106).

[0049] The management device 14 switches the operation state of the primary power source 10 to the ON state (S107). As a result, power is supplied from the vehicle battery 2 to the load 4, the storage 5, and the management device 14 via the primary power source 10 and the secondary power source 11.

[0050] If the start switch 30 is turned ON while the management device 14 is executing the degradation determination process for the EDLC 12, the management device 14 ends the degradation determination process for the EDLC 12 and sets the operation state of the primary power source 10 to the ON state. Furthermore, if the start switch 30 is turned ON while the management device 14 is executing the degradation determination process for the EDLC 12, the management device 14 may set the operation state of the primary power source 10 to the ON state after the degradation determination process for the EDLC 12 is completed.

[0051] Next, the deterioration diagnosis of the EDLC 12 according to the embodiment will be described with reference to Fig. 6. Fig. 6 is a time chart for explaining the deterioration diagnosis of the EDLC 12.

[0052] At time t0, when the start switch 30 is switched from ON to OFF, the operating state of the primary power source 10 changes from ON to OFF. Furthermore, since power supply from the vehicle battery 2 is stopped, power is supplied from the EDLC 12 to the load 4 and the like. As a result, the voltage of the EDLC 12 drops. Furthermore, measurement of the time that power is supplied from the EDLC 12 to the load 4 and the like begins.

[0053] At time t1, when the power supply time of the EDLC 12 is less than the predetermined time, the voltage of the EDLC 12 falls below the predetermined voltage. Since the power supply time until the voltage of the EDLC 12 falls below the predetermined voltage is less than the predetermined time, it is determined that the EDLC 12 has deteriorated. The operating state of the primary power supply 10 is changed from the OFF state to the ON state.

[0054] Then, when the shutdown process is completed at time t2, the vehicle system 1 is changed from ON to OFF, and the vehicle system 1 is shut down.

[0055] The management device 14 determines the deterioration of the EDLC 12 mounted on the vehicle system 1. The management device 14 includes a switching unit 25 and a determination unit 24. When the vehicle system 1 is stopped, the switching unit 25 stops the power supply from the vehicle battery 2 to the load 4 and causes the EDLC 12 to supply the power consumed in the backup process. When the vehicle system 1 is stopped, the determination unit 24 determines the deterioration of the EDLC 12 based on the power supply state of the EDLC 12 when a predetermined elapsed condition is satisfied after the start of power supply by the EDLC 12.

[0056] This allows the management device 14 to appropriately determine the deterioration of the EDLC 12 used as a backup power supply.

[0057] It is also conceivable that the deterioration diagnosis of the EDLC 12 is performed when the vehicle system 1 is started or while the vehicle is running. However, if the deterioration diagnosis of the EDLC 12 is performed when the vehicle system 1 is started, there is a risk that some functions of the vehicle system 1 will be suspended until the deterioration diagnosis of the EDLC 12 is completed. Furthermore, for example, processing to be performed when the vehicle battery 2 loses power cannot be executed until the deterioration diagnosis of the EDLC 12 is completed and the EDLC 12 is recharged. Therefore, for example, if a power loss actually occurs in the vehicle battery 2, there is a risk that the backup processing cannot be executed.

[0058] When the vehicle system 1 is stopped, the management device 14 according to the embodiment performs a deterioration diagnosis of the EDLC 12, thereby preventing some vehicle functions from being stopped when starting up the vehicle system 1. Therefore, the management device 14 can appropriately perform a backup process when a power loss occurs in the vehicle battery 2.

[0059] Furthermore, when a deterioration diagnosis of the EDLC 12 is performed at the start of the vehicle system 1, the deterioration diagnosis of the EDLC 12 cannot be performed until charging of the EDLC 12 is completed. Furthermore, the EDLC 12 that is discharged during the deterioration diagnosis of the EDLC 12 must be recharged, consuming power from the vehicle battery 2.

[0060] When the vehicle system 1 is stopped, the management device 14 according to the embodiment can quickly perform a deterioration diagnosis of the EDLC 12 by performing a deterioration diagnosis of the EDLC 12. Furthermore, when the vehicle system 1 is stopped, the management device 14 performs a deterioration diagnosis of the EDLC 12, which eliminates the need to charge the EDLC 12 immediately after the deterioration diagnosis of the EDLC 12, thereby reducing power consumption of the vehicle battery 2.

[0061] When performing a deterioration diagnosis of the EDLC 12 at the start of the vehicle system 1, it is necessary to accurately monitor the charging current of the EDLC 12, which may increase the cost of a device for performing the deterioration diagnosis.

[0062] The management device 14 according to the embodiment performs a deterioration diagnosis of the EDLC 12 when the vehicle system 1 is stopped, thereby making it possible to reduce the cost of a device for performing the deterioration diagnosis of the EDLC 12.

[0063] When the vehicle system 1 is stopped, if the EDLC 12 is left with a large amount of energy stored therein, the EDLC 12 may deteriorate.

[0064] When the vehicle system 1 is stopped, the management device 14 according to the embodiment supplies power from the EDLC 12 to the load 4 and performs a degradation diagnosis of the EDLC 12, thereby discharging the EDLC 12 and suppressing degradation of the EDLC 12. When the vehicle system 1 is stopped, the EDLC 12 self-discharges, but the management device 14 executes a degradation diagnosis process to consume the energy stored in the EDLC 12, thereby suppressing degradation of the EDLC 12.

[0065] While the vehicle system 1 is stopped, the EDLC 12 may be kept in a charged state so that the voltage of the EDLC 12 does not drop.

[0066] However, in this case, if the EDLC 12, which has a large self-discharge, is kept in a charged state, the standby power consumption of the vehicle system 1 increases.

[0067] When the vehicle system 1 is stopped, the management device 14 according to the embodiment consumes the power of the EDLC 12, thereby suppressing the deterioration of the EDLC 12 and suppressing standby power consumption in the vehicle system 1.

[0068] The power consumption in the backup process is the power that is actually consumed when the vehicle battery 2 loses power.

[0069] When the EDLC 12 is used as a backup power supply, the energy stored in the EDLC 12 varies depending on the individual product of the vehicle system 1. For example, in a vehicle system 1 that uses components (such as the load 4) that consume a lot of power, the power consumption during backup processing becomes large.

[0070] If the deterioration determination of the EDLC 12 is performed in accordance with the vehicle system 1 that consumes a large amount of power, there is a risk that the EDLC 12 may be erroneously determined to be deteriorated even when the EDLC 12 is not actually deteriorated.

[0071] In the degradation determination process for the EDLC 12, the management device 14 according to the embodiment supplies the power actually consumed in the backup process from the EDLC 12, thereby enabling accurate determination of degradation of the EDLC 12 in each vehicle system 1. In other words, the management device 14 can accurately determine the actual degradation state of the EDLC 12 and determine the true life limit of the EDLC 12.

[0072] It is known that the internal resistance value of the EDLC 12 varies greatly depending on the temperature, so when determining the deterioration of the EDLC 12 without using the embodiment, it may be necessary to measure the temperature of the EDLC 12.

[0073] In contrast, the management device 14 according to the embodiment can determine the deterioration of the EDLC 12 without considering the temperature by supplying the power actually consumed in the backup process from the EDLC 12. In other words, the management device 14 can accurately determine the deterioration of the EDLC 12 by performing the deterioration determination of the EDLC 12 under the same conditions as when a power loss occurs in the vehicle battery 2.

[0074] The management device 14 can determine the deterioration of the EDLC 12 without adding a circuit or the like for determining the deterioration of the EDLC 12. Therefore, the management device 14 can determine the deterioration of the EDLC 12 while suppressing costs.

[0075] If a separate discharge circuit is provided to determine the deterioration of the EDLC 12, the discharge circuit cannot discharge a large amount of power, which may result in a large discrepancy with the power consumed in the backup process, making it difficult to accurately determine the deterioration of the EDLC 12. The management device 14 can accurately determine the deterioration of the EDLC 12 by determining the deterioration of the EDLC 12 without providing a separate discharge circuit to determine the deterioration of the EDLC 12.

[0076] The determining unit 24 determines that the EDLC 12 has deteriorated if the power supply time from when the EDLC 12 starts supplying power until the voltage of the EDLC 12 drops to a predetermined voltage or less is less than the predetermined time.

[0077] As a result, when the vehicle system 1 is stopped, the management device 14 can determine whether the EDLC 12 has deteriorated at the timing when the voltage of the EDLC 12 becomes equal to or lower than the predetermined voltage, and can perform the deterioration determination based on the voltage of the EDLC 12. Therefore, the management device 14 can suppress a voltage drop of the load 4 and the like when determining whether the EDLC 12 has deteriorated.

[0078] The predetermined voltage is a voltage higher than the voltage at which the shutdown process, which is executed when the vehicle system 1 is stopped, is stopped.

[0079] As a result, when vehicle system 1 is stopped, management device 14 can prevent the shutdown process from being terminated midway due to a drop in voltage, and can complete the shutdown process.

[0080] The switching unit 25 controls the primary power source 10, which can cut off the power supply from the vehicle battery 2 to the load 4, to stop the power supply from the vehicle battery 2 to the load 4 when the vehicle system 1 is stopped.

[0081] As a result, when the vehicle system 1 is stopped, the management device 14 can execute the degradation determination process for the EDLC 12 under the same conditions as when a power loss occurs in the vehicle battery 2. Therefore, by executing the degradation determination process for the EDLC 12, the management device 14 can accurately determine whether or not the backup process can be executed by the power supply from the EDLC 12.

[0082] When a predetermined elapsed condition is satisfied after the start of power supply by the EDLC 12, the switching unit 25 controls the primary power source 10 to resume power supply from the vehicle battery 2 to the load 4.

[0083] This allows the management device 14 to complete the shutdown process that is executed when the vehicle system 1 is stopped.

[0084] The management device 14 according to the modified example may determine that the EDLC 12 is not degraded if the voltage of the EDLC 12 is equal to or higher than a predetermined voltage after a predetermined time has elapsed since the EDLC 12 started supplying power.

[0085] This allows the management device 14 to keep the time required for the degradation determination process of the EDLC 12 constant.

[0086] When stopping the vehicle system 1, the in-vehicle power supply device 3 according to the modified example may use a comparator to generate a voltage drop signal for the EDLC 12 and input the generated voltage drop signal to the management device 14. Furthermore, when the voltage of the EDLC 12 falls below a predetermined voltage, the in-vehicle power supply device 3 according to the modified example may use a comparator to generate an ON signal for the primary power supply 10 and send the ON signal to the primary power supply 10.

[0087] When stopping the vehicle system 1, the management device 14 according to the modified example may execute a dummy process that consumes power corresponding to the power consumed by the backup process, thereby consuming power from the EDLC 12.

[0088] Furthermore, the management device 14 according to the modified example may set the predetermined time, for example, based on the difference in power consumption between the dummy process and the backup process. This allows the management device 14 according to the modified example to end the degradation determination process for the EDLC 12 before the power consumed by the backup process is consumed, thereby shortening the time required for the degradation determination process for the EDLC 12.

[0089] The management device 14 according to the modified example may not execute the degradation determination process for the EDLC 12 when the vehicle system 1 is stopped in a state where the operating time of the vehicle system 1 is short and the EDLC 12 is not sufficiently charged. For example, the management device 14 according to the modified example detects the voltage of the EDLC 12 when the start switch 30 is turned OFF, and does not execute the degradation determination process for the EDLC 12 when the detected voltage is less than a voltage at which degradation determination for the EDLC 12 can be executed. Furthermore, the management device 14 according to the modified example does not execute the degradation determination process for the EDLC 12 when the start switch 30 is turned OFF and the operating time of the vehicle system 1 is less than a predetermined operating time.

[0090] When vehicle system 1 is stopped while the operating time of vehicle system 1 is short and EDLC 12 is not sufficiently charged, management device 14 according to the modified example may turn off the operating state of primary power supply 10 and not execute the degradation determination process for EDLC 12. In other words, management device 14 according to the modified example discharges EDLC 12 by supplying power from EDLC 12 to load 4, etc., but does not execute the degradation determination process for EDLC 12.

[0091] As a result, when vehicle system 1 is stopped, management device 14 according to the modified example can prevent energy stored in EDLC 12 from being maintained in a large state, thereby preventing deterioration of EDLC 12.

[0092] In a vehicle system 1 according to a modified example, the EDLC 12 may be connected closer to the vehicle battery 2 than the primary power supply 10, as shown in FIG. 7 . FIG. 7 is an explanatory diagram showing an example configuration of a vehicle system 1 according to a modified example. In the vehicle system 1 according to the modified example, the voltage of the EDLC 12 is higher than the voltage of the primary power supply 10. In the vehicle system 1 according to the modified example, a switch 40 is provided closer to the vehicle battery 2 than the point where the EDLC 12 is connected. When the vehicle system 1 is stopped, the management device 14 turns off the switch 40 to prevent power from being supplied from the vehicle battery 2.

[0093] Further advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. [Explanation of symbols]

[0094] 1 Vehicle system (power supply system) 2 Vehicle battery (power source) 3 On-vehicle power supply unit 4. Load 5. Storage 10 Primary power supply (shutoff mechanism) 11 Secondary power supply 12 EDLC 14 Management device (deterioration diagnosis device) 21 Control section 22 Acquisition Department 24 Judgment section 25 Switching section 26. Information Department 30 Start switch

Claims

1. A degradation diagnosis device for determining degradation of an electric double layer capacitor mounted on a power supply system, comprising: a switching unit that stops the power supply from the power supply to the load when the power supply system is stopped and causes the electric double layer capacitor to supply power corresponding to the power consumption in the backup process of the load; a determination unit that determines, when the power supply system is stopped, degradation of the electric double layer capacitor based on a power supply state of the electric double layer capacitor when a predetermined elapsed condition is satisfied after the start of power supply by the electric double layer capacitor; A deterioration diagnosis device comprising:

2. 2. The degradation diagnosis device according to claim 1, wherein the determination unit determines that the electric double layer capacitor has deteriorated if, when the power supply system is stopped, a time period from when the supply of power by the electric double layer capacitor starts to when the voltage of the electric double layer capacitor becomes equal to or lower than a predetermined voltage is shorter than a predetermined time period.

3. 2. The degradation diagnosis device according to claim 1, wherein the determination unit determines that the electric double layer capacitor has deteriorated if, when the power supply system is stopped, a voltage of the electric double layer capacitor is less than a predetermined voltage after a predetermined time has elapsed since the electric double layer capacitor started to supply power.

4. 4. The degradation diagnosis device according to claim 2, wherein the predetermined voltage is higher than a voltage at which a shutdown process that is executed when the power supply system is stopped is stopped.

5. The degradation diagnosis device according to any one of claims 1 to 4, wherein the switching unit stops the power supply from the power source to the load when the power supply system is stopped by controlling a cut-off mechanism capable of cutting off the power supply from the power source to the load.

6. 6. The degradation diagnosis device according to claim 5, wherein the switching unit controls the cut-off mechanism to resume power supply from the power source to the load when the predetermined elapsed condition is satisfied after the start of power supply by the electric double layer capacitor.

7. 7. The degradation diagnosis device according to claim 1, wherein the power corresponding to the power consumption in the backup process is the power that would actually be consumed if a power loss occurs in the power supply.

8. A degradation diagnosis method for determining degradation of an electric double layer capacitor mounted on a power supply system, comprising: a switching step of stopping the power supply from the power supply to the load when the power supply system is stopped and supplying power corresponding to the power consumption in the backup process of the load from the electric double layer capacitor; a determining step of determining, when the power supply system is stopped, whether the electric double layer capacitor has deteriorated based on a power supply state of the electric double layer capacitor when a predetermined elapsed condition is satisfied after the start of power supply by the electric double layer capacitor; A deterioration diagnosis method comprising:

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