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 this 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 determines a ground fault of a high-voltage power supply system mounted on a vehicle based on a threshold value. The above threshold value is switched according to the state of the vehicle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Grounding methods vary depending on countries, regions, etc. When the grounding method is different, the grounding resistance is different. When the grounding resistance is different, the reference resistance value to be used for detecting a disconnection of the ground wire is also different. The technology of Patent Document 1 does not consider different grounding methods. This specification provides a technology capable of correctly detecting a disconnection of the ground wire for a plurality of grounding methods.

Means for Solving the Problems

[0005] This specification discloses a charging cable for a vehicle. In a first aspect of the present technology, the 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 that detects a disconnection of the ground line by monitoring a ground 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 disconnection of the ground line by comparing the ground 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 a plurality of reference resistance values corresponding to a plurality of grounding methods. Thereby, when monitoring the ground resistance of the ground line, the detection device can correctly detect a disconnection of the ground line by using the reference resistance value corresponding to the specified grounding method.

[0007] In a second aspect, in the first aspect, the charging cable further includes a user interface provided in the control box. The user interface may be connected to the detection device and configured to receive a user's specification of a grounding method. According to the above configuration, the charging cable can receive a user's specification of a grounding method. Therefore, it is possible to correctly detect a disconnection of the ground line for the grounding method specified by the user.

[0008] In a third aspect, in the second aspect, the user interface may include at least one of a plurality of buttons, a dial, and a touch panel operated by the user. The user can specify a grounding method via at least one of a plurality of buttons, a dial, or a touch panel.

[0009] In the fourth aspect, in any one of the first to third aspects, the control box may further include a CCID (abbreviation for Charging Circuit Interrupt Device) interposed on the plurality of power lines.

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

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0012] With reference to the drawings, the charging cable 10 of the embodiment will be described. The charging cable 10 is used for charging the electric vehicle 100. As shown in FIG. 1, the charging cable 10 includes 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 luggage compartment or the like of the electric vehicle 100 in a state of being removed from the external power source and the charging inlet 102.

[0013] The cable main body 14 has a plurality of power lines L1, L2, L3, N and a ground line G. The control box 20 is provided at an intermediate position of the cable main body 14. That is, the control box 20 is provided between the plug 12 and the connector 16 of the cable main body 14. The charging cable 10 of this embodiment is a so-called Mode2 charging cable.

[0014] The control box 20 includes a CCID (abbreviation for Charging Circuit Interrupt Device) 22 and a detection device 24. The CCID 22 includes a relay (see FIG. 2 etc.) that is turned on / off by a control device (not shown). The detection device 24 detects a disconnection of the ground line G.

[0015] The detection device 24 stores a microcomputer (hereinafter referred to as "microcontroller") 26 and a memory 28. The microcontroller 26 executes a process for detecting a disconnection of the ground line G. Specifically, the microcontroller 26 detects a disconnection of the ground line G by monitoring the ground resistance of the ground line G.

[0016] Here, regarding the grounding of the power supply system and equipment, various grounding methods are known. For example, the TN grounding method, the TT grounding method, the IT grounding method, etc. are known. Different grounding methods are adopted depending on the country, region, etc. Generally, the reference of the resistance value of the ground line is different for each grounding method. When different reference resistance values (i.e., threshold values) are used to detect a disconnection of the ground line, false detection of a disconnection of the ground line (for example, a disconnection is detected even though the ground line is not actually disconnected, a disconnection is not detected when the ground line is actually disconnected, etc.) may occur.

[0017] Also, in order to correspond to the reference values of the resistance values of different ground lines, for example, a configuration in which components constituting the charging cable 10 such as the control box 20 used for each grounding method are changed can be considered. However, in this configuration, it is necessary to replace the components constituting the charging cable 10 such as the control box 20 according to the grounding method used. That is, the number of components constituting the charging cable 10 increases.

[0018] Therefore, in order to solve these problems, the memory 28 stores a plurality of reference resistance values corresponding to a plurality of grounding methods. The microcomputer 26 acquires the reference resistance value corresponding to the grounding method from the memory 28 in a state where one grounding method is specified from among the plurality of grounding methods. Then, the microcomputer 26 detects a disconnection of the ground line G by comparing the ground resistance of the ground line G with the reference resistance value already acquired from the memory 28 in a state where one grounding method is specified. For this reason, the charging cable 10 of the present embodiment can be uniformly used in any country or region where any of the TN grounding method, TT grounding method, or IT grounding method is used, without increasing the number of components constituting the charging cable 10 such as the control box 20.

[0019] Also, 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. Button 21a is a button indicating the TN grounding method. Button 21b is a button indicating the TT grounding method. Button 21c is a button indicating the IT grounding method. When any one of the buttons 21a to 21c is selected by the user, the grounding method corresponding to the selected button is stored in the memory 28 as the specified grounding method. In this way, the user can specify the grounding method by selecting any one of the buttons 21a to 21c of the control box 20. Regarding the relationship between various countries and regions and the grounding methods adopted there, for example, it is described in the instruction manual of the charging cable 10 or 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. Also, in order to access the web page of the instruction manual, for example, the control box 20 may be described with the URL of the web page, a code image for accessing the web page, or the like.

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

[0021] As shown in FIG. 2, the plug 12 of the charging cable 10 is connected to the outlet 52 of the power supply system 50. Also, the connector 16 of the charging cable 10 is connected to the charging inlet 102 of the electric vehicle 100. When the TN grounding system is adopted, the equipment (for example, the outlet 52) is connected to the ground of the power supply system 50 via the protective grounding conductor PE. Also, the ground wire G of the cable body 14 is connected to the protective grounding conductor PE. Therefore, in a situation where the grounding is properly performed, the grounding resistance of the ground wire G becomes a value relatively close to zero.

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

[0023] Subsequently, referring to FIG. 3, the TT grounding system will be described. In the TT grounding system, the power supply system is grounded at one point, but the protective grounding conductor is not supplied, and the grounding of the power supply system and the grounding of the equipment are performed independently. The TT grounding system is a grounding system widely adopted, for example, in Japan.

[0024] As shown in FIG. 3, when the TT grounding system is adopted, the equipment (e.g., the 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 grounding of the equipment via the outlet 52. A relatively small impedance occurs between the grounding of the power supply system 50 and the grounding of the equipment. Therefore, in the situation where the grounding is correctly performed, the grounding resistance of the ground wire G becomes a relatively small value. That is, in the situation where the grounding is correctly performed, the grounding resistance of the ground wire G in the TT grounding system is larger than the grounding resistance of the ground wire G in the TN grounding system.

[0025] Therefore, the reference resistance value corresponding to the TT grounding system stored in the memory 28 is set to a larger value (e.g., 1 kΩ) than the reference resistance value corresponding to the TN grounding system. When the user uses the charging cable 10 in an area where the TT grounding system is adopted, the user selects the button 21b of the control box 20. Then, the detection device 24 acquires the reference resistance value corresponding to the TT grounding system from the memory 28. And the detection device 24 monitors the grounding resistance of the ground wire G, and detects the disconnection of the ground wire G based on the grounding resistance of the ground wire G and the acquired reference resistance value. In this way, when the TT grounding system is adopted, the disconnection of the ground wire G can be detected by using the corresponding reference resistance value. That is, the disconnection of the ground wire G can be correctly detected.

[0026] Subsequently, referring to FIG. 4, the IT grounding system will be described. In the IT grounding system, the power supply system is either not grounded at all or grounded via a high impedance. In the example of FIG. 4, the power supply system 50 is grounded via the high impedance 54. The IT grounding system is a grounding system widely adopted, for example, in Norway and the like.

[0027] As shown in FIG. 4, when the IT grounding system is adopted, equipment (for example, 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 grounding of the equipment 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. Therefore, in a situation where the grounding is properly performed, the grounding resistance of the ground wire G becomes a relatively large value. That is, in a situation where the grounding is properly performed, the grounding resistance of the ground wire G in the IT grounding system is larger than the grounding resistance of the ground wire G in the TN grounding system and the grounding resistance of the ground wire G in the TT system.

[0028] Therefore, the reference resistance value corresponding to the IT grounding system stored in the memory 28 is set to a larger value (for example, 500 kΩ) than the reference resistance value corresponding to the TN grounding system and the reference resistance value corresponding to the TT grounding system. When the user uses the charging cable 10 in an area where the IT grounding system is adopted, the user selects the button 21c of the control box 20. Then, the detection device 24 acquires the reference resistance value corresponding to the IT grounding system from the memory 28. And the detection device 24 monitors the grounding resistance of the ground wire G, and detects the disconnection of the ground wire G based on the grounding resistance of the ground wire G and the acquired reference resistance value. In this way, when the IT grounding system is adopted, the disconnection of the ground wire G can be detected by using the corresponding reference resistance value. That is, the disconnection of the ground wire G can be correctly detected.

[0029] Note that in the IT grounding system, due to the grounding method of the grounding system, the grounding resistance of the ground wire G in a situation where the grounding is properly performed becomes a relatively large value. Along with this, the reference resistance value corresponding to the IT grounding system is also set to a relatively large value. It is usually not assumed that a grounding resistance exceeding this reference resistance value is detected. Therefore, in the IT grounding system, it can also be said that the disconnection detection of the ground wire G is substantially unnecessary.

[0030] As described above, in the configuration of this embodiment, the memory 28 of the detection device 24 stores a plurality of reference resistance values corresponding to a plurality of grounding methods. Thereby, when monitoring the grounding resistance of the ground wire G, the detection device 24 can correctly detect the disconnection of the ground wire G by using the reference resistance value corresponding to the specified grounding method. In particular, the charging cable 10 of this embodiment can be uniformly used in any country or region where any of the TN grounding method, TT grounding method, or IT grounding method is used, without increasing the number of components constituting 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] As described above, specific examples of the technology disclosed in this specification have been described in detail, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. Modifications of the above embodiments are listed below.

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

[0034] (Modification 2) In addition to or instead of buttons 21a to 21c, the control box 20 may be provided with a dial for specifying the grounding method, a touch panel capable of specifying the grounding method, etc. In this modification, the dial, touch panel, etc. are an example of the "user interface" of this technology. Generally speaking, the "user interface" of this technology may be anything as long as it is configured to receive the specification of the grounding method by the user.

[0035] (Modification Example 3) In the above-described embodiments, the TN grounding system, TT grounding system, and IT grounding system have been described. However, the present technology is also useful for grounding systems different from these grounding systems.

[0036] The technical elements described in this specification or the drawings exhibit technical utility either alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of purposes simultaneously, and achieving one of those purposes itself has technical utility.

Description of Reference Numerals

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

Claims

1. A charging cable for a vehicle, comprising: 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, wherein the control box has a detection device for detecting a disconnection of the ground line by monitoring a ground 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 disconnection of the ground line by comparing the ground resistance of the ground line with a reference resistance value corresponding to a specified grounding method. A charging cable.

2. The charging cable according to claim 1, further comprising a user interface provided in the control box, wherein the user interface is connected to the detection device and is configured to receive a designation of a grounding method by a user.

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

4. The charging cable according to claim 1, wherein the control box further has a CCID (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 includes at least a TN grounding method, a TT grounding method, and an IT grounding method.

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