Conveying system

Abstract

This invention provides a transport system that can suppress abnormal overheating during charging. [Solution] A transport system including a battery vehicle and a charging plug with a cable, wherein the charging plug of the charging plug with a cable comprises plug terminals 111R, 111S, 111T, a plug-side signal terminal 111R, a locking mechanism that prevents the charging plug from being pulled out of the vehicle charging outlet when locked, and a first switch SA interposed in the voltage path 118, which is ON when locked and OFF when unlocked, the vehicle charging outlet comprises an outlet terminal and an outlet-side signal terminal, and the mounted charger is characterized in that it prohibits charging if it cannot detect the voltage applied from the plug-side signal terminal 111R' to the outlet-side signal terminal.

Description

Technical Field

[0001] The present invention relates to a conveying system.

Background Art

[0002] In a charging plug for an electric vehicle, there is a locking mechanism for preventing the charging plug from being pulled out from the vehicle charging socket during charging (see, for example, Patent Document 1). Such a locking mechanism also exists in a charging plug for a forklift.

[0003] In a forklift, there is also a temperature detection mechanism that uses a thermistor to detect the temperature of the vehicle charging socket and automatically stops charging when the vehicle charging socket overheats abnormally (see, for example, Patent Document 2). This temperature detection mechanism and the above locking mechanism are separate mechanisms and operate independently of each other.

[0004] A temperature detection mechanism using a thermistor requires a detection circuit for detecting the resistance value of the thermistor, a mounting component for installing the thermistor, a harness for transmitting the signal of the thermistor to a control unit (controller), and dedicated software for processing the signal of the thermistor by the control unit, etc. Therefore, when adopting a temperature detection mechanism using a thermistor in an existing forklift, a major modification is required.

[0005] By the way, in a conventional forklift, charging may be performed even when the insertion of the charging plug into the vehicle charging socket is insufficient. In this case, abnormal overheating may occur at the contact portion between the vehicle charging socket and the charging plug. Also, when the charging plug is pulled out during charging, a spark may occur at the contact portion between the vehicle charging socket and the charging plug. Due to these reasons, in a conventional forklift, there is a risk that the resin near the contact portion (for example, the resin case of the charging plug) melts or catches fire.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2013-106391 [Patent Document 2] Japanese Patent Publication No. 2002-27604 [Overview of the project] [Problems that the invention aims to solve]

[0007] The present invention has been made in view of the above circumstances, and its objective is to provide a transport system that can suppress abnormal overheating during charging. [Means for solving the problem]

[0008] To solve the above problems, the transport system according to the present invention is A battery vehicle equipped with a battery, an onboard charger for charging the battery, and a vehicle charging outlet connected to the onboard charger, A charging plug with a cable configured to be connectable to the aforementioned vehicle charging outlet, A transport system including, The aforementioned charging plug with cable is A power cable for connecting to an external power supply, The vehicle comprises a charging plug configured to be detachable from the vehicle charging outlet, The aforementioned charging plug is A plug terminal for supplying power from the external power source to the battery vehicle, The plug-side signal terminal connected to the plug terminal via a voltage path, A locking mechanism that prevents the charging plug from being pulled out of the vehicle charging outlet when it is locked, The system includes a first switch interposed in the voltage path, which is ON when the locked state is reached and OFF when the locked state is released, The aforementioned vehicle charging outlet is The outlet terminal that contacts the plug terminal, It comprises a plug-side signal terminal that contacts the outlet-side signal terminal, The aforementioned onboard charger is characterized in that it prohibits charging if it cannot detect the voltage applied from the plug-side signal terminal to the outlet-side signal terminal.

[0009] In the aforementioned transport system, The charging plug further comprises a second switch interposed in the voltage path, The second switch can be configured to be ON when the amount of the charging plug inserted into the vehicle charging outlet is equal to or greater than a predetermined threshold, and OFF when the amount of insertion is less than the threshold.

[0010] In the aforementioned transport system, The charging plug further comprises a thermal fuse interposed in the voltage path, The thermal fuse can be configured to be connected to the plug terminal in a way that allows heat to be conducted.

[0011] In the aforementioned transport system, The thermal fuse is connected to the outlet terminal via a metal terminal, The aforementioned metal terminals are The connection part connected to the aforementioned outlet terminal, A cylindrical section in which the thermal fuse is placed, The arrangement portion can be configured to face the end of the plug terminal.

[0012] In the aforementioned transport system, The insertion portion of the outlet-side signal terminal that is inserted into the plug-side signal terminal can be configured to be shorter than the insertion portion of the outlet terminal that is inserted into the plug terminal.

[0013] In the aforementioned transport system, The aforementioned onboard charger is A power conversion unit that converts the AC power input via the AC power line from the vehicle charging socket into DC power and outputs the DC power to the battery; A control unit that controls the power conversion unit; and The power conversion unit includes A transformer; A switch circuit provided on the primary side of the transformer, which supplies the AC power to the transformer when in the on state and cuts off the supply of the AC power to the transformer when in the off state; A rectifier circuit provided on the secondary side of the transformer; and The control unit includes An AC connection detection unit that detects the AC voltage applied to the vehicle charging socket; A switch control unit that controls the on state and the off state of the switch circuit and turns off the switch circuit when the AC voltage is not detected by the AC connection detection unit; and The AC voltage detected by the AC connection detection unit can be configured to be the voltage applied from the plug-side signal terminal to the socket-side signal terminal.

Effect of the Invention

[0014] According to the present invention, a transport system capable of suppressing abnormal overheating during charging can be provided.

Brief Description of the Drawings

[0015] [Figure 1] It is a diagram showing a transport system according to the present invention. [Figure 2] [[ID=3,6]](A) It is a diagram showing a charging plug of the present invention. (B) It is a diagram showing the arrangement of each terminal in the charging plug of the present invention. (C) It is a diagram showing a modification of the arrangement of each terminal. [Figure 3] It is a diagram showing the attachment structure of a metal terminal in the charging plug of the present invention. [Figure 4] It is a diagram showing a vehicle charging socket of the present invention. [Figure 5] It is a circuit diagram of a mounted charger of the present invention. [Figure 6] (A) This figure shows a modified charging plug. (B) This figure shows a modified vehicle charging outlet. [Modes for carrying out the invention]

[0016] Hereinafter, embodiments of the transport system according to the present invention will be described with reference to the attached drawings.

[0017] Figure 1 shows a transport system 1 according to one embodiment of the present invention. The transport system 1 includes at least one charging plug 100 with a cable and at least one forklift 200 (corresponding to the "battery vehicle" of the present invention).

[0018] The charging plug with cable 100 comprises a charging plug 110 and a power cable 120. The charging plug 110 is configured to be matesable with a vehicle charging outlet 210, which will be described later. The power cable 120 is configured to be connectable to an external power source (in this embodiment, a three-phase AC power source provided in a facility such as a factory or warehouse). The charging plug with cable 100 supplies AC power from the external power source to the forklift 200. The power cable 120 may consist of a single power cable, or it may consist of multiple power cables (including extension cables) connected in series.

[0019] Figure 2(A) shows the structure of the charging plug 110. The charging plug 110 includes plug terminals 111R, 111S, and 111T that correspond to three phases, a plug-side signal terminal 111R', a ground terminal 111E, a plug-side terminal block 112, a plug-side connection part 113, a cover body 114, a lock pin 115A and a lock release button 115B, metal terminals 116R, 116S, and 116T, thermal fuses 117R, 117S, and 117T, and a voltage path 118.

[0020] Plug terminals 111R, 111S, and 111T are terminals corresponding to three phases (R phase, S phase, and T phase), and the configuration of each terminal is the same. Plug terminal 111R has a recess on one side into which the outlet terminal 211R (described later) is inserted, and on the other side a metal terminal 116R and the R phase wire R are connected. Plug terminal 111S has a recess on one side into which the outlet terminal 211S (described later) is inserted, and on the other side a metal terminal 116S and the S phase wire S are connected. Plug terminal 111T has a recess on one side into which the outlet terminal 211T (described later) is inserted, and on the other side a metal terminal 116T and the T phase wire T are connected. The wires R, S, and T are drawn out from the power cable 120.

[0021] The plug-side signal terminal 111R' has the same axial length as the plug terminals 111R, 111S, and 111T, but a smaller diameter than the plug terminals 111R, 111S, and 111T. The plug-side signal terminal 111R' has a recess on one side into which the outlet-side signal terminal 211R' (described later) is inserted, and one end of the voltage path 118 is connected to the other side. The other end of the voltage path 118 is connected to the other side of the plug terminal 111R.

[0022] The ground terminal 111E has a recess on one side into which the ground terminal 211E (described later) is inserted, and the ground wire E is connected to the other side. The ground wire E is drawn out from the power cable 120.

[0023] Figure 2(B) shows the arrangement of plug terminals 111R, 111S, 111T, plug-side signal terminal 111R', and ground terminal 111E. Figure 2(B) is a front view of the plug-side connection section 113. Plug terminals 111R, 111S, and 111T are located in the center of the plug-side connection section 113 in the left-right direction, while plug-side signal terminal 111R' and ground terminal 111E are located to the right of the center in the left-right direction. Furthermore, plug-side signal terminal 111R' is located between plug terminal 111S and plug terminal 111T.

[0024] Note that the above arrangement is just one example and can be changed as appropriate depending on the relationship with the forklift 200. For example, as shown in Figure 2(C), the plug terminals 111R, 111S, and 111T may be placed in the center in the height direction, and the plug-side signal terminal 111R' may be placed to the right of the center in the left-right direction and between plug terminal 111R and plug terminal 111S.

[0025] The plug-side terminal block 112 is made of resin (for example, epoxy resin) and holds the central portions of the plug terminals 111R, 111S, 111T, the plug-side signal terminal 111R', and the ground terminal 111E. A wall portion 112a is provided on the rear side of the plug-side terminal block 112, as shown in Figure 3. The wall portion 112a is intended to ensure reliable insulation by securing creepage distance between the plug terminals 111R, 111S, 111T, and the ground terminal 111E. The rear end surface of the wall portion 112a protrudes further back than the rear end surfaces of the plug terminals 111R, 111S, 111T, the plug-side signal terminal 111R', and the ground terminal 111E. Note that the wall portion 112a is not shown in Figure 2(A).

[0026] The plug-side connection portion 113 is an annular member provided on the front side of the plug-side terminal block 112 so as to surround the plug terminals 111R, 111S, 111T, the plug-side signal terminal 111R', and the ground terminal 111E. The plug-side connection portion 113 is configured to be matesable with the vehicle charging outlet 210, which will be described later.

[0027] The cover body 114 houses the plug terminals 111R, 111S, 111T, the plug-side signal terminal 111R', the ground terminal 111E, the plug-side terminal block 112, the metal terminals 116R, 116S, 116T, the thermal fuses 117R, 117S, 117T, and the voltage path 118. The cover body 114 has a grip portion that can be grasped by an operator. In this embodiment, the cover body 114 is formed of a transparent material, but it may be formed of an opaque material.

[0028] The locking pin 115A and the unlocking button 115B constitute the "locking mechanism" of the present invention. The locking pin 115A and the unlocking button 115B are connected by a mechanical mechanism. When the unlocking button 115B is not pressed, the locking mechanism is in a state where the locking pin 115A protrudes from the outer surface of the plug-side connection part 113 (locked state). On the other hand, when the unlocking button 115B is pressed, the locking mechanism is in a state where the locking pin 115A does not protrude from the outer surface of the plug-side connection part 113 (unlocked state). The locking mechanism in the locked state prevents the charging plug 110 from being pulled out of the vehicle charging outlet 210.

[0029] As shown in Figure 3, the metal terminals 116R, 116S, and 116T are connected to the plug terminals 111R, 111S, and 111T by screws 119 while holding the thermal fuses 117R, 117S, and 117T. The metal terminals 116R, 116S, and 116T are made of a metal with high thermal conductivity (for example, copper) and all have the same structure. In this embodiment, flag terminals are used as the metal terminals 116R, 116S, and 116T.

[0030] The metal terminals 116R, 116S, and 116T each have a connecting portion 116a and an arrangement portion 116b. The connecting portion 116a is located on the upper surface of the plug terminals 111R, 111S, and 111T, and the arrangement portion 116b is located opposite the end (rear end face) of the plug terminals 111R, 111S, and 111T.

[0031] The connecting portion 116a is formed on a flat plate and has a through hole that is smaller than the head of the screw 119 and larger than the threaded portion of the screw 119. The placement portion 116b is formed in a cylindrical shape (in this embodiment, a cylindrical shape). A thermal fuse 117R is placed in the placement portion 116b for the metal terminal 116R, a thermal fuse 117S is placed in the placement portion 116b for the metal terminal 116S, and a thermal fuse 117T is placed in the placement portion 116b for the metal terminal 116T. The thermal fuses 117R, 117S, and 117T are fixed inside the cylinder of the placement portion 116b, for example, by an insulating adhesive.

[0032] As described above, the thermal fuses 117R, 117S, and 117T are connected to the plug terminals 111R, 111S, and 111T via metal terminals 116R, 116S, and 116T in a heat-conductive manner. The thermal fuses 117R, 117S, and 117T all have the same configuration. For example, non-resettable thermal fuses in which the temperature-sensing element contains a fusible alloy can be used as the thermal fuses 117R, 117S, and 117T. The thermal fuses 117R, 117S, and 117T include a first lead connected to one side of the temperature-sensing element and a second lead connected to the other side of the temperature-sensing element. The first and second leads are insulated with an insulating tube or the like.

[0033] In this embodiment, a sleeve s is used as a connecting means to connect the first lead, second lead of the thermal fuses 117R, 117S, and 117T and the wires of the voltage path 118. However, any connecting means other than a sleeve s can be used as the connecting means.

[0034] The voltage path 118 has one end connected to the plug-side signal terminal 111R' and the other end connected to the plug terminal 111R. In this embodiment, one end of the wire constituting the voltage path 118 is crimped to a ring terminal, and the ring terminal is screwed to the plug-side signal terminal 111R' with a screw 119. Similarly, the other end of the wire constituting the voltage path 118 is crimped to a ring terminal, and the ring terminal is screwed to the plug terminal 111R together with the metal terminal 116R with a screw 119. Note that this connection method is just one example, and any connection method can be adopted.

[0035] The voltage path 118 includes a first switch SA, a second switch SB, and thermal fuses 117R, 117S, and 117T. The first switch SA, the second switch SB, and the thermal fuses 117R, 117S, and 117T are connected in series.

[0036] The first switch SA is a switch that is ON when the locking mechanism, consisting of a locking pin 115A and a release button 115B, is in the locked state, and OFF when it is in the unlocked state. When the first switch SA is OFF, that is, when the release button 115B is pressed and the lock is released, the voltage path 118 is non-conductive.

[0037] In this embodiment, a microswitch (limit switch) is used as the first switch SA. For example, the actuator portion of the microswitch is connected to the locking mechanism, and the contact portion of the microswitch is interposed in the voltage path 118. This allows the on / off state of the first switch SA to be linked to the locked / unlocked state of the locking mechanism.

[0038] The second switch SB is a switch that turns ON when the insertion depth of the charging plug 110 into the vehicle charging outlet 210 is greater than or equal to a predetermined threshold, and turns OFF when the insertion depth is less than the predetermined threshold. The predetermined threshold is set to the insertion depth when the charging plug 110 is inserted as far as it can go into the vehicle charging outlet 210 (hereinafter referred to as the fully inserted state). When the second switch SB is OFF, that is, when the charging plug 110 is not in the fully inserted state (not fully inserted state), the voltage path 118 becomes non-conductive.

[0039] In this embodiment, a microswitch (limit switch) is used as the second switch SB. For example, the actuator portion of the microswitch is positioned at the location where it contacts the vehicle charging outlet 210 when the device is fully inserted, and the contact portion of the microswitch is interposed in the voltage path 118. This allows the on / off state of the second switch SB to be linked to the fully inserted state / not fully inserted state. The location where the device contacts the vehicle charging outlet 210 when the device is fully inserted is, for example, the location of the ground terminal 111E that the ground terminal 211E of the vehicle charging outlet 210 contacts when the device is fully inserted.

[0040] Furthermore, if abnormal overheating occurs at plug terminal 111R, the heat is transferred to the thermal fuse 117R via metal terminal 116R, causing the thermal fuse 117R to melt (activate), and the voltage path 118 becomes non-conductive. If abnormal overheating occurs at plug terminal 111S, the heat is transferred to the thermal fuse 117S via metal terminal 116S, causing the thermal fuse 117S to melt (activate), and the voltage path 118 becomes non-conductive. Similarly, if abnormal overheating occurs at plug terminal 111T, the heat is transferred to the thermal fuse 117T via metal terminal 116T, causing the thermal fuse 117T to melt (activate), and the voltage path 118 becomes non-conductive.

[0041] As described above, the voltage path 118 becomes non-conductive when the locking mechanism is unlocked, when the charging plug 110 is not fully inserted, or when abnormal overheating occurs at any of the plug terminals 111R, 111S, or 111T. On the other hand, it becomes conductive when the locking mechanism is locked, when the charging plug 110 is fully inserted, and when abnormal overheating does not occur at any of the plug terminals 111R, 111S, or 111T.

[0042] Referring again to Figure 1, in this embodiment, the forklift 200 is a reach-type forklift. However, the forklift 200 may be a counterbalanced type forklift or any other type of forklift. Also, in this embodiment, the forklift 200 is a manned forklift operated by an operator, but it may be an unmanned forklift capable of autonomous driving.

[0043] The forklift 200 comprises a body 201. The front of the body 201 is provided with a pair of left and right straddle legs 202 and a load handling device 203. The load handling device 203 comprises a mast 204 that is movable in the front-rear direction along the straddle legs 202 and forks 205 that are movable up and down on the mast 204. The load handling device 203 may have other attachments in addition to, or in place of, the forks 205.

[0044] A driver's seat 206 for the operator to sit in while standing is provided on the rear right side of the vehicle body 201. An operating unit 207, including an accelerator lever and various operating levers for the cargo handling device 203, is provided in front of the driver's seat 206. A steering wheel 208 for steering is provided on the left side of the driver's seat 206. A head guard 209 is provided above the driver's seat 206. A vehicle charging outlet 210 is provided on the side wall of the driver's seat 206. Note that the vehicle charging outlet 210 is not limited to this position and can be provided at any other location.

[0045] Inside the vehicle body 201 are an onboard charger 220 and a battery 230. In this embodiment, the battery 230 is a lead-acid battery, but it may also be a lithium-ion battery or another type of battery.

[0046] As shown in Figure 4, the vehicle charging outlet 210 includes outlet terminals 211R, 211S, and 211T that are compatible with three phases, an outlet-side signal terminal 211R', an earth terminal 211E, an outlet-side terminal block 212, and an outlet-side connection part 213.

[0047] The outlet terminals 211R, 211S, and 211T are terminals corresponding to three phases (R phase, S phase, and T phase), and the configuration of each terminal is the same. Outlet terminal 211R has a shape that allows one end to be inserted into the recess of plug terminal 111R, and the R phase wire R is connected to the other end. Outlet terminal 211S has a shape that allows one end to be inserted into the recess of plug terminal 111S, and the S phase wire S is connected to the other end. Outlet terminal 211T has a shape that allows one end to be inserted into the recess of plug terminal 111T, and the T phase wire T is connected to the other end. The wires R, S, and T are connected to the mounted charger 220.

[0048] The outlet-side signal terminal 211R' has a shape that allows one end to be inserted into the recess of the plug-side signal terminal 111R', and the other end is connected to the wire R'. The length of the part of the outlet-side signal terminal 211R' that is inserted into the recess (insertion part) is the same as the length of the insertion part of outlet terminals 211R, 211S, and 211T, but its diameter is smaller than the diameter of outlet terminals 211R, 211S, and 211T. The ground terminal 211E has a shape that allows one end to be inserted into the recess of ground terminal 111E, and the other end is connected to the ground wire E.

[0049] The outlet-side terminal block 212 is made of resin (for example, epoxy resin) and holds outlet terminals 211R, 211S, 211T, outlet-side signal terminal 211R', and ground terminal 211E. On the rear side of the outlet-side terminal block 212 (the side facing the vehicle body 201), a wall portion (not shown) may be provided to ensure creepage distance between each terminal of outlet terminals 211R, 211S, 211T, and ground terminal 211E to ensure reliable insulation.

[0050] The outlet-side connection portion 213 is an annular member provided on the front side (external side of the vehicle body 201) of the outlet-side terminal block 212 so as to surround the outlet terminals 211R, 211S, 211T, the outlet-side signal terminal 211R', and the ground terminal 211E. The outlet-side connection portion 213 is configured to allow the plug-side connection portion 113 to be fitted into it. In addition, the inner circumferential surface of the outlet-side connection portion 213 is provided with a receiving portion (not shown) for receiving the lock pin 115A that protrudes from the outer circumferential surface of the plug-side connection portion 113.

[0051] Figure 5 shows the circuit diagram of the onboard charger 220. The onboard charger 220 comprises terminals T1 to T6, a power conversion unit 220A, and a control unit 220B.

[0052] Terminals T1 to T4 are AC input terminals. Terminal T1 is connected to outlet terminal 211R via the R-phase wire R. Terminal T2 is connected to outlet terminal 211S via the S-phase wire S. Terminal T3 is connected to outlet terminal 211T via the T-phase wire T. Terminal T4 is connected to outlet-side signal terminal 211R' via the wire R'. Terminals T5 and T6 are DC output terminals. Terminal T5 is connected to the positive terminal of battery 230, and terminal T6 is connected to the negative terminal of battery 230.

[0053] The power conversion unit 220A includes a switch circuit 221, a transformer 222, and a rectifier circuit 223. The control unit 220B is composed of, for example, a microcontroller and includes an AC connection detection unit 224 and a switch control unit 225.

[0054] The switch circuit 221 is located on the primary side of the transformer 222 and supplies AC power to the transformer 222 when charging, and cuts off the supply of AC power to the transformer 222 when it is not charging or in the event of an abnormality.

[0055] The switch circuit 221 consists of a magnetic switch. The magnetic switch comprises three switch units 221R, 221S, and 221T that switch between an on state and an off state, and a coil unit MC. The switch units 221R, 221S, and 221T are interposed in the AC power lines of the corresponding phases. The coil unit MC is interposed in the signal line L1 (power line), and when current flows through the signal line L1, it turns on the switch units 221R, 221S, and 221T, and when no current flows through the signal line L1, it turns off the switch units 221R, 221S, and 221T. When the switch units 221R, 221S, and 221T are in the off state, the supply of AC power to the transformer 222 is cut off.

[0056] The switch circuit 221 may include a thermal relay. The thermal relay comprises, for example, three heat elements and relay contacts. The three heat elements are connected in series with three switch units 221R, 221S, and 221T, and the relay contacts are connected in series with the coil unit MC. When the heat elements detect a predetermined overcurrent, the relay contacts are open, and the supply of current to the coil unit MC is interrupted. When the heat elements do not detect a predetermined overcurrent, the relay contacts are closed, and the supply of current to the coil unit MC is not interrupted.

[0057] The transformer 222 comprises a primary coil and a secondary coil (not shown). The primary coil is connected to a switch circuit 221, and the secondary coil is connected to a rectifier circuit 223. The transformer 222 transforms (for example, steps down) the AC power input to the primary coil and outputs it from the secondary coil.

[0058] The rectifier circuit 223 rectifies AC to DC. In this embodiment, the rectifier circuit 223 is a three-phase bridge diode in which six diodes are connected in a bridge configuration. A smoothing capacitor may be provided after the three-phase bridge diode. The high-potential side (positive side) output terminal of the rectifier circuit 223 is connected to terminal T5, and the low-potential side (negative side) output terminal of the rectifier circuit 223 is connected to terminal T6.

[0059] The AC connection detection unit 224 is connected to the outlet-side signal terminal 211R' via signal line L2 (electric wire) and electric wire R', and detects the AC voltage applied to the outlet-side signal terminal 211R'.

[0060] The switch control unit 225 controls the on and off states of the switch circuit 221. Specifically, the switch control unit 225 controls the on and off states of the switch units 221R, 221S, and 221T by controlling the current supply to the coil unit MC.

[0061] When the AC connection detection unit 224 detects an AC voltage, and the operator operates the charging start switch (charging start button) provided on the vehicle body 201, the switch control unit 225 supplies current to the coil unit MC and turns on the switch units 221R, 221S, and 221T. The switch control unit 225 monitors the voltage between terminals T5 and T6 and causes the power conversion unit 220A to charge the battery 230. When the voltage between terminals T5 and T6 reaches a predetermined voltage value (for example, the voltage value when the battery 230 is fully charged), the switch control unit 225 stops supplying current to the coil unit MC and turns off the switch units 221R, 221S, and 221T, thereby ending the charging of the battery 230.

[0062] On the other hand, if the AC connection detection unit 224 no longer detects an AC voltage during charging, the switch control unit 225 stops supplying current to the coil unit MC and turns off the switches 221R, 221S, and 221T. This cuts off the supply of AC power to the transformer 222, and the charging of the battery 230 automatically stops. Also, if the AC connection detection unit 224 does not detect an AC voltage before charging starts, the switch control unit 225 does not supply current to the coil unit MC even if the charging start switch (charging start button) is operated by the operator, and keeps the switches 221R, 221S, and 221T in the off state. As a result, the supply of AC power to the transformer 222 does not start, and the charging of the battery 230 does not start.

[0063] The AC voltage applied to the outlet-side signal terminal 211R' is the R-phase voltage supplied via the plug-side signal terminal 111R' of the charging plug 110 and the voltage path 118. As described above, the voltage path 118 becomes non-conductive when the locking mechanism is unlocked, when the charging plug 110 is not fully inserted, or when abnormal overheating occurs at any of the plug terminals 111R, 111S, or 111T. When the voltage path 118 is non-conductive, the AC connection detection unit 224 no longer detects an AC voltage, and charging automatically stops (charging will not start if it has not yet started). In other words, charging of the battery 230 is prohibited.

[0064] As described above, in the transport system 1 according to this embodiment, charging is stopped (charging is not started) when the locking mechanism is unlocked, so for example, when the charging plug 110 is pulled out during charging, sparks at the contact point between the vehicle charging outlet 210 and the charging plug 110 can be suppressed. Furthermore, in the transport system 1 according to this embodiment, charging is stopped (charging is not started) when the charging plug 110 is not fully inserted, so for example, abnormal overheating caused by insufficient contact between the vehicle charging outlet 210 and the charging plug 110 can be suppressed. Moreover, in the transport system 1 according to this embodiment, the thermal fuses 117R, 117S, and 117T stop charging (charging is not started) when abnormal overheating occurs at any of the plug terminals 111R, 111S, or 111T, so the progression of such abnormal overheating can be suppressed.

[0065] According to the transport system 1 of this embodiment, the forklift 200 only needs to connect the signal line L2 of the AC connection detection unit 224 to the wire R' of the outlet side signal terminal 211R', so it can be applied to existing forklifts without requiring major modifications. Furthermore, the charging plug 110 can be handled with a single voltage path 118 by connecting the first switch SA, the second switch SB and the thermal fuses 117R, 117S, and 117T in series. In addition, the three-phase compatible thermal fuses 117R, 117S, and 117T can handle abnormal overheating that occurs at the plug terminals 111R, 111S, and 111T of each phase.

[0066] In this embodiment, the thermal fuses 117R, 117S, and 117T are connected to the plug terminals 111R, 111S, and 111T in a heat-conductive manner via metal terminals 116R, 116S, and 116T made of a metal with high thermal conductivity (for example, copper). Therefore, in the event of abnormal overheating, heat is quickly transferred to the thermal fuses 117R, 117S, and 117T. Moreover, since the thermal fuses 117R, 117S, and 117T are positioned inside the cylinders of the metal terminals 116R, 116S, and 116T, heat is transferred to the thermal fuses 117R, 117S, and 117T from all directions. As a result, the performance (operation) of the thermal fuses 117R, 117S, and 117T can be stabilized and accelerated. Furthermore, by using the metal terminals 116R, 116S, and 116T, space can be saved, and the size of the charging plug 110 can be avoided. The metal terminals 116R, 116S, and 116T can be fastened with screws 119, which can improve work efficiency.

[0067] [Differentiation] Figure 6(A) shows a modified charging plug 110', and Figure 6(B) shows a modified vehicle charging outlet 210' corresponding to the charging plug 110'. The transport system 1 according to the above embodiment may be equipped with a charging plug 110' and a vehicle charging outlet 210' instead of the charging plug 110 and the vehicle charging outlet 210.

[0068] The charging plug 110' has the same configuration as the charging plug 110 of the above embodiment, except that it does not have a second switch SB. In the charging plug 110', even when not fully inserted, the voltage path 118 is conductive as long as the locking mechanism is in the locked state (first switch SA is ON) and the thermal fuses 117R, 117S, and 117T have not melted (activated).

[0069] The vehicle charging outlet 210' has the same configuration as the vehicle charging outlet 210 of the above embodiment, except that the length of the insertion part of the outlet-side signal terminal 211R' is shorter than the length of the insertion parts of the outlet terminals 211R, 211S, and 211T.

[0070] The plug portion of the outlet-side signal terminal 211R' is configured to be of a length that allows the AC connection detection unit 224 to detect AC voltage when the charging plug 110' is fully inserted, while preventing the AC connection detection unit 224 from detecting AC voltage when the charging plug 110' is not fully inserted. This configuration allows for the use of a modified charging plug 110' in which the second switch SB is omitted from the charging plug 110.

[0071] In the modified configuration, the AC connection detection unit 224 cannot detect the AC voltage when the charging plug 110' is not fully inserted. Therefore, as with the above embodiment, it is possible to suppress abnormal overheating caused by insufficient contact between the vehicle charging outlet 210' and the charging plug 110'. In the modified configuration, the configuration is the same as the above embodiment except for the charging plug 110' and the vehicle charging outlet 210', so the modified configuration has the same effects as the above embodiment.

[0072] [Other variations] Although embodiments of the transport system according to the present invention have been described above, the present invention is not limited to the above embodiments.

[0073] The transport system according to the present invention includes a battery, an onboard charger for charging the battery, a battery vehicle equipped with a vehicle charging outlet connected to the onboard charger, and a charging plug with a cable configured to be connectable to the vehicle charging outlet, wherein the charging plug with a cable comprises a power cable for connecting to an external power source and a charging plug configured to be matesable to the vehicle charging outlet, the charging plug comprises a plug terminal for supplying power from an external power source to the battery vehicle, a plug-side signal terminal connected to the plug terminal via a voltage path, a locking mechanism for preventing the charging plug from being pulled out of the vehicle charging outlet when locked, and a first switch interposed in the voltage path which is on when locked and off when unlocked, the vehicle charging outlet comprises an outlet terminal that contacts the plug terminal and an outlet-side signal terminal that contacts the plug-side signal terminal, and the onboard charger can be configured as appropriate to prohibit charging if it cannot detect the voltage applied from the plug-side signal terminal to the outlet-side signal terminal.

[0074] In the above embodiment, the voltage path 118 includes a first switch SA, a second switch SB, and thermal fuses 117R, 117S, and 117T. However, the voltage path 118 only needs to include at least one of the first switch SA, the second switch SB, and the thermal fuses 117R, 117S, and 117T.

[0075] In the above embodiment, the thermal fuses 117R, 117S, and 117T are connected to the plug terminals 111R, 111S, and 111T via metal terminals 116R, 116S, and 116T. However, they may also be connected to the plug terminals 111R, 111S, and 111T by a heat-conductive method other than the metal terminals 116R, 116S, and 116T, or they may be connected directly to the plug terminals 111R, 111S, and 111T. Furthermore, when using metal terminals 116R, 116S, and 116T, their shape and other characteristics may be appropriately modified.

[0076] In the above embodiment, a forklift 200 is given as an example of a battery-powered vehicle, but the battery-powered vehicle may be a material handling vehicle other than a forklift (for example, a transport vehicle, construction machinery, or agricultural machinery). [Explanation of Symbols]

[0077] 1. Conveying System 100 Charging Plugs with Cables 110 Charging Plug 111R, 111S, 111T plug terminals 111R' Plug-side signal terminal 111E Ground terminal 112 Plug-side terminal block 113 Plug-side connection 114 Cover body 115A Locking Pin 115B Unlock button 116R, 116S, 116T metal terminal 117R, 117S, 117T Thermal Fuse 118 Voltage Path 120 Power Cable 200 forklifts 210 Vehicle charging outlets 211R, 211S, 211T outlet terminals 211R' Outlet side signal terminal 211E Ground terminal 212 Outlet-side terminal block 213 Outlet side connection 220 Onboard Charger 220A Power Conversion Unit 220B Control Unit 230 batteries

Claims

1. A battery vehicle equipped with a battery, an onboard charger for charging the battery, and a vehicle charging outlet connected to the onboard charger, A charging plug with a cable configured to be connectable to the aforementioned vehicle charging outlet, A transport system including, The aforementioned charging plug with cable is A power cable for connecting to an external power supply, The vehicle comprises a charging plug configured to be detachable from the vehicle charging outlet, The aforementioned charging plug is A plug terminal for supplying power from the external power source to the battery vehicle, The plug-side signal terminal connected to the plug terminal via a voltage path, A locking mechanism that prevents the charging plug from being pulled out of the vehicle charging outlet when it is locked, The system includes a first switch interposed in the voltage path, which is ON when the locked state is in place and OFF when the locked state is released, The aforementioned vehicle charging outlet is The outlet terminal that contacts the plug terminal, It comprises a plug-side signal terminal that contacts the outlet-side signal terminal, The aforementioned onboard charger prohibits charging if it cannot detect the voltage applied from the plug-side signal terminal to the outlet-side signal terminal. A transport system characterized by the following features.

2. The charging plug further comprises a second switch interposed in the voltage path, The second switch turns ON when the amount of the charging plug inserted into the vehicle charging outlet is equal to or greater than a predetermined threshold, and turns OFF when the amount of insertion is less than the threshold. The transport system according to feature 1.

3. The charging plug further comprises a thermal fuse interposed in the voltage path, The thermal fuse is connected to the plug terminal in a way that allows heat to be conducted. The transport system according to feature 1.

4. The thermal fuse is connected to the outlet terminal via a metal terminal, The aforementioned metal terminals are The connection part connected to the aforementioned outlet terminal, A cylindrical section in which the thermal fuse is placed, The arrangement portion is located opposite the end of the plug terminal. The transport system according to feature 3.

5. The insertion portion of the outlet-side signal terminal that is inserted into the plug-side signal terminal is shorter than the insertion portion of the outlet terminal that is inserted into the plug terminal. The transport system according to feature 1.

6. The aforementioned onboard charger is A power conversion unit that converts AC power input from the vehicle charging outlet via AC power lines into DC power and outputs the DC power to the battery, The system comprises a control unit for controlling the power conversion unit, The power conversion unit is Transformer and, A switch circuit is provided on the primary side of the transformer, which supplies AC power to the transformer when it is ON and cuts off the supply of AC power to the transformer when it is OFF. The transformer comprises a rectifier circuit provided on the secondary side, The control unit, An AC connection detection unit that detects the AC voltage applied to the vehicle charging outlet, The system includes a switch control unit that controls the ON state and the OFF state of the switch circuit, and that puts the switch circuit into the OFF state when the AC connection detection unit does not detect the AC voltage, The AC voltage detected by the AC connection detection unit is the voltage applied from the plug-side signal terminal to the outlet-side signal terminal. The transport system according to feature 1.

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