Charging cable

Abstract

To provide a technique capable of correctly detecting the disconnection of a ground wire for a plurality of grounding systems.SOLUTION: A charging cable includes: a cable body having a plurality of power lines and a ground line; and a control box provided at an intermediate position of the cable body. The control box has a detection device for detecting the disconnection of the ground line by monitoring the ground resistance of the ground line. The detection device stores a plurality of reference resistance values corresponding to a plurality of ground systems, and detects the disconnection of the ground line by comparing the ground resistance of the ground line with a reference resistance value corresponding to a designated ground system.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The technology disclosed in the present specification relates to a charging cable for vehicles. [Background Art]

[0002] Patent Document 1 discloses a ground fault detection device. The ground fault detection device performs ground fault determination for a high-voltage power supply system mounted on a vehicle based on a threshold value. The threshold value is switched depending on the state of the vehicle. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 2013-092466 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] Different grounding methods are adopted depending on countries, regions and the like. Different grounding methods result in different grounding resistances. Different grounding resistances also lead to different reference resistance values that should be used for detecting disconnection of a ground line. The technology of Patent Document 1 does not take into consideration different grounding methods. The present specification provides a technology capable of correctly detecting disconnection of a ground line for a plurality of grounding methods. [Means for Solving the Problem]

[0005] This specification discloses a charging cable for a vehicle. In a first aspect of this technology, the charging cable comprises a cable body having a plurality of power lines and a ground line, and a control box located at an intermediate position of the cable body, wherein the control box has a detection device that detects a break in the ground line by monitoring the grounding resistance of the ground line, the detection device stores a plurality of reference resistance values ​​corresponding to a plurality of grounding methods, and detects a break in the ground line by comparing the grounding resistance of the ground line with a reference resistance value corresponding to a specified grounding method.

[0006] In the above configuration, the detection device stores multiple reference resistance values ​​corresponding to multiple grounding methods. This allows the detection device to correctly detect a break in the ground wire by using the reference resistance value corresponding to the specified grounding method when monitoring the grounding resistance of the ground wire.

[0007] In a second embodiment, the control box may further include a user interface, which is connected to the detection device and configured to accept a user's specification of the grounding method. With this configuration, the charging cable can accept a user's specification of the grounding method. This allows for the correct detection of a break in the ground wire for the grounding method specified by the user.

[0008] In a third embodiment, the user interface may include at least one of a plurality of buttons, dials, or touch panels operated by the user. The user can specify the grounding method via at least one of the plurality of buttons, dials, or touch panels.

[0009] In a fourth embodiment, in any one of the first to third embodiments described above, the control box may further include CCIDs (Charging Circuit Interrupt Devices) interposed on the plurality of power lines.

[0010] In the fifth embodiment, in any one of the first to fourth embodiments, the plurality of grounding methods may include at least a TN grounding method, a TT grounding method, and an IT grounding method. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram of a charging cable. [Figure 2] This is a schematic diagram illustrating the TN grounding method. [Figure 3] This is a schematic diagram illustrating the TT grounding system. [Figure 4] This is a schematic diagram illustrating the IT grounding method. [Modes for carrying out the invention]

[0012] The charging cable 10 of the embodiment will be described with reference to the drawings. The charging cable 10 is used to charge the electric vehicle 100. As shown in Figure 1, the charging cable 10 comprises a plug 12, a cable body 14, a connector 16, and a control box 20. The plug 12 is provided at one end of the cable body 14 and is connected to an external power source. The connector 16 is provided at the other end of the cable body 14 and is connected to the charging inlet 102 of the electric vehicle 100. The charging cable 10 is usually mounted in the cargo area of ​​the electric vehicle 100, etc., after being disconnected from the external power source and the charging inlet 102.

[0013] The cable body 14 has multiple power lines L1, L2, L3, N and a ground line G. The control box 20 is located in the middle of the cable body 14. That is, the control box 20 is located between the plug 12 and the connector 16 of the cable body 14. The charging cable 10 in this embodiment is a so-called Mode 2 charging cable.

[0014] The control box 20 includes a CCID (Charging Circuit Interrupt Device) 22 and a detection device 24. The CCID 22 includes a relay (see Figure 2, etc.) that is turned on / off by a control device (not shown). The detection device 24 detects a break in the ground wire G.

[0015] The detection device 24 stores a microcomputer (hereinafter referred to as "microcontroller") 26 and a memory 28. The microcontroller 26 performs processing to detect a break in the ground wire G. Specifically, the microcontroller 26 detects a break in the ground wire G by monitoring the grounding resistance of the ground wire G.

[0016] Here, various grounding methods are known for grounding power systems and equipment. For example, TN grounding, TT grounding, and IT grounding methods are known. Different grounding methods are adopted depending on the country or region. Generally, the reference value for the resistance of the ground wire differs for each grounding method. If the reference value for the resistance of the ground wire differs, the reference resistance value (i.e., threshold) that should be used to detect a break in the ground wire will also differ. If a common reference resistance value is used for different grounding methods, false detection of a break in the ground wire may occur (for example, a break in the ground wire is detected even though a break has not actually occurred, or a break in the ground wire is not detected even though a break has actually occurred, etc.).

[0017] Furthermore, in order to accommodate different ground wire resistance standards, one could consider a configuration in which the components of the charging cable 10, such as the control box 20 used for each grounding method, are changed. However, in this configuration, it is necessary to replace the components of the charging cable 10, such as the control box 20, depending on the grounding method used. In other words, the number of components that make up the charging cable 10 increases.

[0018] To address these challenges, the memory 28 stores multiple reference resistance values ​​corresponding to multiple grounding methods. When one grounding method is selected from among the multiple grounding methods, the microcontroller 26 retrieves the reference resistance value corresponding to that grounding method from the memory 28. Then, when one grounding method is selected, the microcontroller 26 detects a break in the ground line G by comparing the grounding resistance of the ground line G with the reference resistance value retrieved from the memory 28. For this reason, the charging cable 10 of this embodiment can be used uniformly in countries and regions where any of the TN grounding, TT grounding, or IT grounding methods are used, without increasing the number of components that make up the charging cable 10, such as the control box 20.

[0019] Further, as shown in FIG. 1, the control box 20 includes three buttons 21a to 21c. The buttons 21a to 21c are connected to the detection device 24. The button 21a is a button indicating the TN grounding system. The button 21b is a button indicating the TT grounding system. The button 21c is a button indicating the IT grounding system. When any one of the buttons 21a to 21c is selected by a user, the grounding system corresponding to the selected button is stored in the memory 28 as the specified grounding system. In this way, the user can specify the grounding system by selecting any one of the buttons 21a to 21c of the control box 20. It should be noted that the relationship between various countries and regions and the grounding systems adopted therein is described, for example, in the instruction manual of the charging cable 10 and the like. The instruction manual may be a paper medium provided together with the charging cable 10, or may be displayed as a web page. Further, in order to access the web page of the instruction manual, for example, the control box 20 may have the URL of the web page, a code image for accessing the web page, or the like described thereon.

[0020] Hereinafter, each grounding system will be described with reference to FIGS. 2 to 4. First, the TN grounding system will be described with reference to FIG. 2. In the TN grounding system, the power supply system is grounded at one point, and a protective grounding conductor PE for grounding equipment to that point is provided. The TN grounding system illustrated in FIG. 2 is a so-called TN-S grounding system that separates the neutral line N and the protective grounding conductor PE. As TN grounding systems, besides the TN-S grounding system, there are known a TN-C grounding system that shares the neutral line N and the protective grounding conductor PE, and a TN-C-S grounding system that partially shares the neutral line N and the protective grounding conductor PE. The TN grounding system is a grounding system widely adopted, for example, in Europe and America.

[0021] As shown in Figure 2, a plug 12 of a charging cable 10 is connected to an outlet 52 of a power supply system 50. A connector 16 of the charging cable 10 is connected to a charging inlet 102 of an electric vehicle. When the TN grounding system is employed, a device (e.g., the outlet 52) is connected to the ground of the power supply system 50 via a protective earthing conductor PE. A ground wire G of a cable body 14 is connected to the protective earthing conductor PE. Therefore, in a state where grounding is correctly performed, the ground resistance of the ground wire G is a value relatively close to zero.

[0022] For this reason, the reference resistance value corresponding to the TN grounding system stored in the memory 28 is set to a relatively small value (e.g., 100 Ω). When a user uses the charging cable 10 in a region where the TN grounding system is employed, the user selects a button 21a of a control box 20. Then, the detection device 24 acquires the reference resistance value corresponding to the TN grounding system from the memory 28. The detection device 24 monitors the ground resistance of the ground wire G, and detects disconnection of the ground wire G based on the ground resistance of the ground wire G and the acquired reference resistance value. For example, disconnection of the ground wire G may be detected when the ground resistance of the ground wire G is greater than the reference resistance value. In this way, when the TN grounding system is employed, disconnection of the ground wire G can be detected using the corresponding reference resistance value. That is, disconnection of the ground wire G can be correctly detected.

[0023] Next, the TT grounding system will be described with reference to Figure 3. In the TT grounding system, the power supply system is grounded at one point, but no protective earthing conductor is supplied, and the grounding of the power supply system and the grounding of the device are performed independently. The TT grounding system is, for example, a grounding system widely employed in Japan.

[0024] As shown in Figure 3, when the TT grounding method is adopted, the equipment (e.g., outlet 52) ​​is grounded independently of the grounding of the power supply system 50. The ground wire G of the cable body 14 is connected to the equipment's grounding via the outlet 52. A relatively small impedance is generated between the grounding of the power supply system 50 and the equipment's grounding. Therefore, when grounding is performed correctly, the grounding resistance of the ground wire G is a relatively small value. In other words, when grounding is performed correctly, the grounding resistance of the ground wire G in the TT grounding method is greater than the grounding resistance of the ground wire G in the TN grounding method.

[0025] Therefore, the reference resistance value corresponding to the TT grounding method stored in memory 28 is set to a larger value (for example, 1 kΩ) than the reference resistance value corresponding to the TN grounding method. When a user uses the charging cable 10 in an area where the TT grounding method is adopted, they select button 21b on the control box 20. The detection device 24 then retrieves the reference resistance value corresponding to the TT grounding method from memory 28. The detection device 24 then monitors the grounding resistance of the ground wire G and detects a break in the ground wire G based on the grounding resistance of the ground wire G and the retrieved reference resistance value. In this way, when the TT grounding method is adopted, a break in the ground wire G can be detected using the corresponding reference resistance value. In other words, a break in the ground wire G can be correctly detected.

[0026] Next, the IT grounding method will be explained with reference to Figure 4. In the IT grounding method, the power supply system is either not grounded at all or grounded via a high impedance. In the example in Figure 4, the power supply system 50 is grounded via a high impedance 54. The IT grounding method is a grounding method widely adopted in places such as Norway.

[0027] As shown in Figure 4, when the IT grounding method is adopted, the equipment (e.g., outlet 52) ​​is grounded independently of the grounding of the power supply system 50. The ground wire G of the cable body 14 is connected to the equipment's grounding via the outlet 52. Since the power supply system 50 is grounded via the high impedance 54, a relatively large impedance is generated between the grounding of the power supply system 50 and the grounding of the equipment. For this reason, when grounding is performed correctly, the grounding resistance of the ground wire G will be a relatively large value. That is, when grounding is performed correctly, the grounding resistance of the ground wire G in the IT grounding method is greater than the grounding resistance of the ground wire G in the TN grounding method and the grounding resistance of the ground wire G in the TT method.

[0028] Therefore, the reference resistance value corresponding to the IT grounding method stored in memory 28 is set to a value greater than the reference resistance value corresponding to the TN grounding method and the reference resistance value corresponding to the TT grounding method (for example, 500kΩ). When a user uses the charging cable 10 in an area where the IT grounding method is adopted, they select button 21c on the control box 20. The detection device 24 then retrieves the reference resistance value corresponding to the IT grounding method from memory 28. The detection device 24 then monitors the grounding resistance of the ground wire G and detects a break in the ground wire G based on the grounding resistance of the ground wire G and the retrieved reference resistance value. In this way, when the IT grounding method is adopted, a break in the ground wire G can be detected using the corresponding reference resistance value. In other words, a break in the ground wire G can be correctly detected.

[0029] In the IT grounding system, the grounding resistance of the ground wire G is relatively high when grounding is performed correctly, due to the specific grounding method used. Consequently, the reference resistance value corresponding to the IT grounding system is also set to a relatively high value. It is not usually expected that a grounding resistance exceeding this reference resistance value will be detected. Therefore, in the IT grounding system, it can be said that detecting a break in the ground wire G is practically unnecessary.

[0030] As described above, in this embodiment, the memory 28 of the detection device 24 stores multiple reference resistance values ​​corresponding to multiple grounding methods. This allows the detection device 24 to correctly detect a break in the ground wire G by using the reference resistance value corresponding to the specified grounding method when monitoring the grounding resistance of the ground wire G. In particular, the charging cable 10 of this embodiment can be used uniformly in countries and regions where any of the TN grounding, TT grounding, or IT grounding methods are used, without increasing the number of components that make up the charging cable 10, such as the control box 20.

[0031] Buttons 21a to 21c are an example of the "user interface" of this technology.

[0032] The specific examples of the technology disclosed herein have been described in detail above, but these are merely illustrative and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes to the specific examples illustrated above. Modifications of the above embodiments are listed below.

[0033] (Modification 1) The control box 20 does not need to have buttons 21a to 21c. In this case, the grounding method may be specified by another method (e.g., communication). In this modification, the "user interface" can be omitted.

[0034] (Modification 2) The control box 20 may be equipped with, in addition to or instead of, buttons 21a to 21c, a dial for specifying the grounding method, a touch panel for specifying the grounding method, etc. In this modification, the dial, touch panel, etc. are examples of the "user interface" of this technology. Generally speaking, the "user interface" of this technology can be anything as long as it is configured to accept the user's specification of the grounding method.

[0035] (Modification 3) In the above embodiments, the TN grounding method, TT grounding method, and IT grounding method were described, but this technology is also useful for grounding methods other than these.

[0036] The technical elements described herein or in the drawings demonstrate technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated herein or in the drawings can achieve multiple objectives simultaneously, and achieving even one of these objectives constitutes technical usefulness in itself. [Explanation of Symbols]

[0037] 10: Charging cable, 12: Plug, 14: Cable body, 16: Connector, 20: Control box, 21a~21c: Buttons, 22: CCID, 24: Detection device, 26: Microcontroller, 28: Memory, 50: Power system, 52: Outlet, 100: Electric vehicle, 102: Charging inlet

Claims

1. A charging cable for vehicles, A cable body having multiple power lines and ground lines, The cable body includes a control box located at an intermediate position, The control box has a detection device that detects a break in the ground wire by monitoring the grounding resistance of the ground wire. The detection device stores multiple reference resistance values ​​corresponding to multiple grounding methods, and detects a break in the ground wire by comparing the grounding resistance of the ground wire with a reference resistance value corresponding to a specified grounding method. Charging cable.

2. The control box further includes a user interface, The charging cable according to claim 1, wherein the user interface is connected to the detection device and is configured to accept a user's specification of a grounding method.

3. The charging cable according to claim 2, wherein the user interface includes at least one of a plurality of buttons, dials, or touch panels operated by the user.

4. The charging cable according to claim 1, wherein the control box further comprises CCIDs (abbreviation for Charging Circuit Interrupt Device) interposed on the plurality of power lines.

5. The charging cable according to any one of claims 1 to 4, wherein the plurality of grounding methods include at least a TN grounding method, a TT grounding method, and an IT grounding method.

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