Charging system

Abstract

To provide a technique capable of precisely determining whether a form C contact relay is welded.SOLUTION: A charging system includes a battery, a charging inlet, a power supply outlet, a DC charging route, an AC charging route, an AC power supply route, a system main relay, a form C contact relay, a first voltage sensor, a second voltage sensor, and a control unit. The control unit is configured such that welding detection processing for the form C contact relay can be executed. The welding detection processing includes: charging processing; switching processing to give, to the form C contact relay, a switching command for switching the form C contact relay into a second closed sate while keeping the system main relay closed, during execution of the charging processing; and determination processing of, after completion of the switching processing, determining that the form C contact relay is welded if a first voltage and a second voltage are not zero.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a charging system. [Background technology]

[0002] Patent Document 1 discloses a charging system including a battery, a DC charging inlet, an AC charging inlet, a power supply outlet, an AC charging path connecting the battery and the AC charging inlet via an AC-DC conversion unit, a DC charging path connecting the battery and the DC charging inlet and connected in parallel to the AC charging path, an AC power supply path connecting the battery and the power supply outlet via a DC-AC inverter, a first system main relay provided in the AC charging path, and a second system main relay provided in the AC power supply path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-092310 Summary of the Invention [Problem to be solved by the invention]

[0004] Among charging systems, there is a charging system that includes a bidirectional charger installed in an AC charging path. In this charging system, the AC power supply path branches off from a section of the AC charging path that connects the charging inlet and the bidirectional charger toward the power supply outlet. The branch point where the AC power supply path branches off from the AC charging path is provided with a contact C relay that can be switched between a first closed state that connects the battery and the charging inlet via the bidirectional charger and a second closed state that connects the battery and the power supply outlet via the bidirectional charger. A technology that can determine whether the contact C relay is welded is desired.

[0005] This specification provides a technique that can accurately determine whether or not a C-contact relay is welded. [Means for solving the problem]

[0006] In a first aspect disclosed in the present specification, a charging system includes a battery, a charging inlet to which an external charging power source can be attached / detached, a power supply outlet to which an electrical device can be attached / detached, a DC charging path connecting the battery and the charging inlet, an AC charging path connecting the battery and the charging inlet via a bidirectional charger and connected in parallel to the DC charging path, an AC power supply path connecting the battery and the power supply outlet via the bidirectional charger and branching off from a section of the AC charging path connecting the charging inlet and the bidirectional charger toward the power supply outlet, and a system main provided on the DC charging path and electrically connecting and disconnecting the battery to the charging inlet and electrically connecting and disconnecting the battery to the power supply outlet. a contact C relay provided at a branch point where the AC charging path branches off from the AC power supply path, the contact C relay being switchable between a first closed state in which the battery and the charging inlet are connected via the bidirectional charger and a second closed state in which the battery and the power supply outlet are connected via the bidirectional charger, a first voltage sensor provided in the AC charging path between the contact C relay and the bidirectional charger and detecting a first voltage, a second voltage sensor provided in the AC power supply path between the contact C relay and the power supply outlet and detecting a second voltage, and a control device connected to the first voltage sensor and the second voltage sensor and controlling the system main relay, the contact C relay, and the bidirectional charger. The control device is configured to be able to detect welding of the contact C relay.The welding detection process includes a charging process in which, while the system main relay is closed, AC charging power is supplied to the battery via the bidirectional charger from the external charging power source connected to the charging inlet; a switching process in which, while the charging process is being performed, a switching command is given to the C-contact relay to switch the C-contact relay to the second closed state while the system main relay is maintained closed; and a determination process in which, after the switching process is completed, if the first voltage and the second voltage are not zero, the C-contact relay is determined to be welded.

[0007] When an external charging power source is connected to the charging inlet, if the C-contact relay is switched to the second closed state, current stops flowing in the AC charging path on the battery side of the C-contact relay. Current also stops flowing in the AC power supply path. Therefore, if the C-contact relay is not welded, the first voltage and the second voltage are zero. In the above configuration, the control device determines that the C-contact relay is welded if the first voltage and the second voltage are not zero after the switching process is completed. Therefore, it is possible to accurately determine whether the C-contact relay is welded. [Brief explanation of the drawings]

[0008] [Figure 1] 2 is a diagram showing a schematic configuration of an electric vehicle 2 in which a C-contact relay 32 is in a first closed state. FIG. [Figure 2] 10 is a diagram showing a schematic configuration of an electric vehicle 2 when a C-contact relay 32 is in a second closed state. FIG. [Figure 3] FIG. 10 is a flowchart of a welding detection process. DETAILED DESCRIPTION OF THE INVENTION

[0009] The electric vehicle 2 will be described with reference to Figures 1 and 2. As an example, the electric vehicle 2 may be a battery electric vehicle, a hybrid electric vehicle, a fuel cell electric vehicle, or a plug-in hybrid electric vehicle. The electric vehicle 2 includes a charging system 10 and a traction motor (not shown).

[0010] The charging system 10 includes a battery 12, a charging inlet 14, and a power supply outlet 16. The battery 12 includes a plurality of battery cells. The battery cells are rechargeable battery cells, such as lithium-ion battery cells or all-solid-state battery cells. The charging inlet 14 is configured to allow an external charging power source 100 to be attached / detached. The external charging power source 100 is, for example, a DC charging stand, an AC charging stand, or a power outlet installed in a home or the like. The charging inlet 14 receives charging power for charging the battery 12 from the external charging power source 100. The power supply outlet 16 is configured to allow an electrical device to be attached / detached. The power supply outlet 16 outputs AC power to electrical devices such as home appliances, personal computers, smartphones, tablet devices, etc.

[0011] The charging system 10 further includes a DC charging path 20, an AC charging path 22, an AC power supply path 24, a bidirectional charger 26, a system main relay 28, a DC relay 30, a C-contact relay 32, a first voltage sensor 34, a second voltage sensor 36, and a third voltage sensor 38.

[0012] DC charging path 20 connects battery 12 and charging inlet 14. AC charging path 22 connects battery 12 and charging inlet 14 via bidirectional charger 26. AC charging path 22 is connected in parallel to DC charging path 20. AC power supply path 24 connects battery 12 and power supply outlet 16 via bidirectional charger 26. AC power supply path 24 branches off from a section of AC charging path 22 that connects charging inlet 14 and bidirectional charger 26 toward power supply outlet 16. In other words, the path of AC charging path 22 that is closer to battery 12 than contact C relay 32 is shared with AC power supply path 24.

[0013] The system main relay 28 and the DC relay 30 are provided in the DC charging path 20. The system main relay 28 is provided closer to the battery 12 than two connections of the DC charging path 20 with the AC charging path 22. The DC relay 30 is provided between the two connections of the DC charging path 20 with the AC charging path 22. The C-contact relay 32 is provided at a branch point (hereinafter simply referred to as the "branch point") where the AC power supply path 24 branches off from the AC charging path 22. The C-contact relay 32 is switchable between a first closed state in which the battery 12 and the charging inlet 14 are connected via the bidirectional charger 26, and a second closed state (see FIG. 2) in which the battery 12 and the power supply outlet 16 are connected via the bidirectional charger 26. The C-contact relay 32 is in the first closed state when a coil (not shown) of the C-contact relay 32 is not energized.

[0014] The bidirectional charger 26 can convert AC power supplied from the external charging power source 100 into DC power. The bidirectional charger 26 can also convert DC power supplied from the battery 12 into AC power.

[0015] The first voltage sensor 34 is provided in the AC charging path 22 between the branch point and the bidirectional charger 26. The second voltage sensor 36 is provided in the AC power supply path 24 between the power supply outlet 16 and the branch point. The third voltage sensor 38 is provided in the AC charging path 22 between the charging inlet 14 and the branch point.

[0016] The charging system 10 further includes a control device 40. The control device 40 is a computer device having a processor, a memory, etc. The control device 40 controls the operation of each component of the charging system 10.

[0017] (Welding detection process; Figure 3) The welding detection process executed by the control device 40 of the charging system 10 will be described with reference to Fig. 3. The control device 40 starts the process of Fig. 3 when an external charging power source that supplies AC power is connected to the charging inlet 14. In the initial state of Fig. 3, the system main relay 28 and the DC relay 30 are open, and no current is applied to the coil of the C-contact relay 32.

[0018] In S10, the control device 40 issues a closing command to the system main relay 28. This connects the battery 12 and the charging inlet 14 via the bidirectional charger 26, as shown in FIG.

[0019] In S12, the control device 40 starts the charging process. As a result, AC power is supplied from an external charging power source to the charging inlet 14. The AC power is converted to DC power in the bidirectional charger 26. The converted DC power is then supplied to the battery 12, thereby charging the battery 12.

[0020] In S14, the control device 40 monitors whether the capacity of the battery 12 is equal to or greater than a predetermined value. The predetermined value is a value slightly lower than the fully charged capacity. If the capacity of the battery 12 is equal to or greater than the predetermined value, the control device 40 determines YES in S14 and proceeds to S16. Note that an increase in the capacity of the battery 12 during the charging process means that at least the battery 12 and the charging inlet 14 are connected by the C-contact relay 32.

[0021] In S16, the control device 40 issues a switching command to the C-contact relay 32. The switching command is a command to switch the C-contact relay 32 to the second closed state.

[0022] In S20, the control device 40 determines whether the first voltage V1 detected by the first voltage sensor 34 and the second voltage V2 detected by the second voltage sensor 36 are zero. If the first voltage V1 and the second voltage V2 are zero (YES in S20), the control device 40 proceeds to S22, and if at least one of the first voltage V1 and the second voltage V2 is not zero (NO in S20), the control device 40 proceeds to S24.

[0023] In S22, the control device 40 determines that the C-contact relay 32 is normal. As shown in FIG. 2, when the C-contact relay 32 is in the second closed state, no current flows from the C-contact relay 32 to the power outlet 16 side or from the C-contact relay 32 to the battery 12 side. As a result, the first voltage V1 and the second voltage V2 are zero. Therefore, when the first voltage V1 and the second voltage V2 are zero, the control device 40 determines that the C-contact relay 32 is not welded. When S22 ends, the control device 40 ends the processing of FIG. 3.

[0024] Furthermore, in S24, the control device 40 determines that the C contact relay 32 is welded. After S22 is completed, the control device 40 ends the processing of FIG.

[0025] As described above, the charging system 10 includes the battery 12, the charging inlet 14, the power supply outlet 16, the DC charging path 20, the AC charging path 22, the AC power supply path 24, the system main relay 28, the C-contact relay 32, the first voltage sensor 34, the second voltage sensor 36, and the control device 40. The control device 40 is configured to be able to perform a process for detecting welding of the C-contact relay 32 (FIG. 3). The welding detection process in FIG. 3 includes a charging process (S12) in which, while the system main relay 28 is closed, AC charging power is supplied from an external charging power source connected to the charging inlet 14 to the battery 12 via the bidirectional charger 26; a switching process (S16) in which, while the charging process is being performed, a switching command is given to the C-contact relay 32 to switch the C-contact relay 32 to the second closed state while the system main relay 28 is maintained closed; and a determination process (S24) in which, after the switching process is completed, the C-contact relay 32 is determined to be welded if the first voltage V1 and the second voltage V2 are not zero (NO in S20).

[0026] When an external charging power source is connected to the charging inlet 14 and the C-contact relay 32 is switched to the second closed state, current stops flowing through the AC charging path 22, which is closer to the battery 12 than the C-contact relay 32. Furthermore, no current flows through the AC power supply path 24. Therefore, if the C-contact relay 32 is not welded, the first voltage V1 and the second voltage V2 are zero. In the above configuration, the control device 40 determines that the C-contact relay 32 is welded if the first voltage V1 and the second voltage V2 are not zero after the switching process is completed. Therefore, it is possible to accurately determine whether the C-contact relay 32 is welded. [Explanation of symbols]

[0027] 2: electric vehicle, 10: charging system, 12: battery, 14: charging inlet, 16: power supply outlet, 20: DC charging path, 22: AC charging path, 24: AC power supply path, 26: bidirectional charger, 28: system main relay, 30: DC relay, 32: C-contact relay, 34: first voltage sensor, 36: second voltage sensor, 38: third voltage sensor, 40: control device, 100: charging power source

Claims

[Claim 1] A battery, A charging inlet that allows an external charging power source to be attached or detached, A power outlet that allows electrical devices to be attached and detached; a DC charging path connecting the battery and the charging inlet; an AC charging path that connects the battery and the charging inlet via a bidirectional charger and is connected in parallel to the DC charging path; an AC power supply path that connects the battery and the power supply outlet via the bidirectional charger and branches off from a section of the AC charging path that connects the charging inlet and the bidirectional charger toward the power supply outlet; a system main relay provided in the DC charging path, electrically connecting and disconnecting the battery to and from the charging inlet and electrically connecting and disconnecting the battery to and from the power supply outlet; a C-contact relay provided at a branch point where the AC power supply path branches off from the AC charging path, the C-contact relay being switchable between a first closed state in which the battery and the charging inlet are connected via the bidirectional charger and a second closed state in which the battery and the power supply outlet are connected via the bidirectional charger; a first voltage sensor provided in the AC charging path between the C-contact relay and the bidirectional charger, the first voltage sensor detecting a first voltage; a second voltage sensor provided in the AC power supply path between the C-contact relay and the power supply outlet, the second voltage sensor detecting a second voltage; a control device connected to the first voltage sensor and the second voltage sensor, and configured to control the system main relay, the C-contact relay, and the bidirectional charger; Equipped with the control device is configured to be able to execute a process for detecting welding of the C-contact relay, The welding detection process includes: a charging process in which, with the system main relay closed, AC charging power from the external charging power source connected to the charging inlet is supplied to the battery via the bidirectional charger; a switching process of giving a switching command to the C-contact relay to switch the C-contact relay to the second closed state while the system main relay is maintained closed during the charging process; a determination process of determining that the C-contact relay is welded when the first voltage and the second voltage are not zero after the switching process is completed; Including, charging system.

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