Bus duct system for charging electric vehicle and electric vehicle charging system including same

Abstract

The present invention relates to an electric vehicle charging system, and includes a bus duct system for charging an electric vehicle. The bus duct system includes: a bus duct line; and a branching device. The bus duct line includes a bus duct connection unit that electrically connects a plurality of bus ducts with each other to form a power supply network. The branching device branches power supplied through the bus ducts and supplies power to an electric vehicle charger. Each bus duct includes a plurality of bus bars and an enclosure accommodating the plurality of bus bars. The plurality of bus bars includes an R-phase bus bar, an S-phase bus bar, a T-phase bus bar, and at least one N-phase bus bar. The branching device comprises: as a plurality of electrical connection members electrically connected to the plurality of bus bars on a one-to-one basis, a first electrical connection member connected to any one of the R-phase bus bar, the S-phase bus bar, and the T-phase bus bar; and a second electrical connection member connected to the N-phase bus bar. The plurality of electrical connection members are electrically connected to only any one of the R-phase, S-phase, and T-phase bus bars and the N-phase bus bar.

Description

Bus duct system for electric vehicle charging and electric vehicle charging system including the same

[0001] The present invention relates to a bus duct system for charging electric vehicles and an electric vehicle charging system including the same. Specifically, the present invention relates to a bus duct system for charging electric vehicles and an electric vehicle charging system including the same, which can simultaneously charge multiple electric vehicles parked in multiple locations and minimize the space required to construct charging facilities.

[0002] The global market share of electric vehicles has been rapidly increasing. Electric vehicles operate by powering a motor powered by a battery. These batteries must be periodically recharged via an electric vehicle charger.

[0003] In parking lots and other locations, electric vehicle chargers are being deployed in a number of locations for charging electric vehicles. As the penetration rate of electric vehicles increases, the deployment of multiple electric vehicle chargers is required, and charging facilities capable of charging multiple electric vehicles simultaneously in a short period of time are also required.

[0004] However, there is a need to build a power grid capable of operating multiple slow or rapid electric vehicle chargers simultaneously, and securing space for installing multiple electric vehicle chargers is a particular issue.

[0005] Figure 1 schematically illustrates the power supply route of an electric vehicle charging system based on a bus duct.

[0006] As illustrated in FIG. 1, an electric vehicle charging system based on a bus duct includes a bus duct (10) for supplying power, a branch box (20) for branching power from the bus duct (10), a distribution board (30) for supplying power branched from the branch box (20) to an electric vehicle charger, etc.

[0007] For example, the bus duct (10) may be equipped with four bus bars that are current flow paths, i.e., R phase, S phase, T phase and N phase bus bars that are neutral wires with different phases, and the branch box (20) is equipped with electrical connecting members such as brushes that electrically connect to each bus bar to transmit the power supplied from the bus bars of each phase to the distribution board (30), and the distribution board (30) resupplies the supplied power to the electric vehicle charger (EV).

[0008] Specifically, the branch box (20) receives three-phase power from all three busbars of the R-phase, S-phase, and T-phase of the bus duct (10) and transmits it to the distribution board (30), and one pair among the R-phase and N-phase, S-phase and N-phase, and T-phase and N-phase pairs can be connected to each of the plurality of circuit breakers (CB) provided in the distribution board (30), and power is supplied to the electric vehicle charger through each circuit breaker (CB).

[0009] This bus duct-based electric vehicle charging system requires a large space to build the charging facility, and also supplies power through a separately installed distribution panel (30), so the power supply route is complex, which may cause additional errors in the power supply.

[0010] Accordingly, there is a need for an electric vehicle charging bus duct system and an electric vehicle charging system including the same that can simultaneously charge multiple electric vehicles while minimizing the space required to build charging facilities.

[0011] The present invention aims to provide an electric vehicle charging bus duct system and an electric vehicle charging system including the same, which can simultaneously charge a plurality of electric vehicles parked in a plurality of areas, minimize the space required to build charging facilities, make the overall system compact, and enable efficient power supply.

[0012] In order to solve the above problem, the present invention,

[0013] A bus duct system for charging an electric vehicle, comprising: a bus duct line constituting a power supply network, including a plurality of bus ducts and a bus duct connection portion electrically connecting the bus ducts; and a branch device for branching power supplied through the bus duct and supplying power to an electric vehicle charger, wherein the bus duct includes a plurality of bus bars and an enclosure accommodating the plurality of bus bars, wherein the plurality of bus bars include R-phase, S-phase, T-phase, and at least one N-phase bus bar, and the branch device includes a plurality of electrical connection members electrically connected one-to-one with the plurality of bus bars, a first electrical connection member connected to any one of the R-phase, S-phase, and T-phase bus bars, and a second electrical connection member connected to the N-phase bus bar, wherein the plurality of electrical connection members are electrically connected only to any one of the R-phase, S-phase, and T-phase bus bars and the N-phase bus bar.

[0014] Here, the branch device is composed of N branch devices across the entire bus duct line, and among the N branch devices, the number of branch devices including a first electrical connection member connecting to an R-phase bus bar is X, the number of branch devices including a first electrical connection member connecting to an S-phase bus bar is Y, and the number of branch devices including a first electrical connection member connecting to a T-phase bus bar is Z, and a bus duct system for charging an electric vehicle is provided, characterized in that it satisfies the following mathematical expression 1.

[0015] [Mathematical Formula 1]

[0016] 3(C max -C min ) / N ≤ 0.25

[0017] In the above mathematical formula 1,

[0018] C maxis the largest value among X, Y and Z, and C min is the smallest value among X, Y, and Z.

[0019] In addition, a bus duct system for charging an electric vehicle is provided, characterized in that each of the plurality of electrical connecting members is electrically connected to each of the plurality of bus bars through a connecting terminal coupled to each of the plurality of bus bars.

[0020] Meanwhile, an electric vehicle charging system is provided, characterized by including the above-described electric vehicle charging bus duct system; and an electric vehicle charger for charging an electric vehicle using power supplied from the branch device.

[0021] Here, the electric vehicle charger provides an electric vehicle charging system characterized in that it includes a charging unit that provides charging power to an electric vehicle, an electric vehicle connection unit that connects the charging unit and the electric vehicle wired or wirelessly, and a control unit that controls the charging unit.

[0022] In addition, an electric vehicle charging system is provided, characterized in that the charging unit is provided inside the branch device.

[0023] And, the electric vehicle connection part provides an electric vehicle charging system characterized by including a charging cable or a wireless charging coil.

[0024] Here, an electric vehicle charging system is provided, characterized in that the electric vehicle connection part includes a charging cable and further includes a cable reel structure capable of pulling out or pulling in the charging cable to adjust the length of the charging cable.

[0025] In addition, the electric vehicle charging system is provided, characterized in that the cable reel structure includes a single reel structure having one pulley on which the charging cable is wound or a double reel structure having two pulleys.

[0026] The electric vehicle charging system according to the present invention is capable of transmitting a large amount of power so as to charge multiple electric vehicles simultaneously through a power supply network by a bus duct, and supplies power directly to an electric vehicle charger in a single phase from a branch device connected to the bus duct, so that a separate distribution panel is unnecessary, thereby minimizing the space required to construct a charging facility, making the configuration of the entire system compact, and exhibiting excellent effects of efficient power supply.

[0027] Figure 1 schematically illustrates the power supply route of an electric vehicle charging system based on a bus duct.

[0028] FIG. 2 is a perspective view of an embodiment of a bus duct line and a branch device of a bus duct system for charging an electric vehicle according to the present invention.

[0029] Figure 3 schematically illustrates the assembly state of the bus duct system for charging electric vehicles illustrated in Figure 2.

[0030] Fig. 4 is a bottom perspective view of a branch device in the bus duct system for electric vehicle charging illustrated in Fig. 2.

[0031] Figure 5 is an enlarged view of a branch connection provided on the lower surface of a branch device commonly used in a bus duct, connected to a bus bar.

[0032] FIG. 6 is an enlarged view of a branch connection part provided on the lower surface of a branch device according to one embodiment of the present invention, which is connected to a busbar.

[0033] FIG. 7 is an enlarged view showing a branch connection part provided on the lower surface of a branch device according to another embodiment of the present invention connected to a busbar.

[0034] FIG. 8 is a schematic illustration of an embodiment of a state of an electrical connecting member placed under a circuit breaker with the cover of the housing opened and the circuit breaker removed in each branch device illustrated in FIG. 2.

[0035] FIG. 9 schematically illustrates a power supply route in an electric vehicle charging system including the bus duct system for electric vehicle charging illustrated in FIG. 2.

[0036] Figure 10 schematically illustrates an electric vehicle charging system with an additional configuration of a cable reel structure according to the present invention.

[0037] Fig. 11 is an enlarged view of the configuration of a single reel structure among the cable reel structures illustrated in Fig. 10.

[0038] Fig. 12 is an internal perspective view of the slip ring portion in Fig. 11.

[0039] Fig. 13 schematically illustrates a speed controller applicable to the single-reel structure illustrated in Fig. 11.

[0040] Fig. 14 schematically illustrates a magnetic damper applicable to the single-reel structure illustrated in Fig. 11.

[0041] Fig. 15 schematically illustrates the laminated structure of a cable wound on a pulley of the single-reel structure illustrated in Fig. 11.

[0042] Fig. 16 schematically illustrates the configuration of a double reel structure among the cable reel structures illustrated in Fig. 10.

[0043] Figure 17 is an enlarged view of the double reel structure illustrated in Figure 16.

[0044] Fig. 18 is a schematic diagram of a cross-section of a pulley around which a cable is wound in the double-reel structure illustrated in Fig. 17.

[0045] Figure 19 is an enlarged view of the ratchet stopper in Figure 17.

[0046] Fig. 20 is an exploded perspective view of a ball bearing stopper applicable to the cable reel structure illustrated in Fig. 10.

[0047] Figure 21 schematically illustrates the operation of the ball bearing stopper in Figure 20.

[0048] Fig. 22 schematically illustrates another operating aspect of the ball bearing stopper in Fig. 20.

[0049] Fig. 23 schematically illustrates the operation of the sub-ball bearing in the ball bearing stopper illustrated in Fig. 20.

[0050] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosure is thorough and complete, and to sufficiently convey the spirit of the present invention to those skilled in the art. Like reference numbers designate like elements throughout the specification.

[0051] FIG. 2 is a perspective view of one embodiment of a bus duct system for charging an electric vehicle according to the present invention, and FIG. 3 schematically illustrates an assembled state of the bus duct system for charging an electric vehicle illustrated in FIG. 2.

[0052] As illustrated in FIGS. 2 and 3, the bus duct system for charging an electric vehicle according to the present invention may include a bus duct line (100) in which a plurality of bus ducts (100a, 100b) are connected to each other through a bus duct connection (140) to form a power supply network, a plurality of branch devices (200) for branching power supplied through one of the plurality of bus ducts (100a, 100b) and supplying it to an electric vehicle charger, and at least a portion of the electric vehicle charger may be integrally provided within the housing of the branch device (200) or may be provided externally separately from the branch device (200).

[0053] Here, the bus duct (100a, 100b) is constructed along a line by housing the bus bar corresponding to the conductor within a cover having a duct-shaped hollow portion without exposing it to the outside, thereby preventing damage or safety accidents caused by the cable coming into contact with people or objects, minimizing adverse effects on the appearance, minimizing the space required for constructing a power supply network, and providing an advantage of being able to supply sufficient power to charge multiple electric vehicles simultaneously.

[0054] Specifically, each of the plurality of bus ducts (100a, 100b) may include a plurality of bus bars (110) as current flow paths, for example, an R-phase bus bar (111), an S-phase bus bar (112), and a T-phase bus bar (113) that supply power of different phases, and at least one N-phase bus bar (114) that is a neutral line, and an outer case (120) that accommodates the bus bars (100).

[0055] Hereinafter, in the embodiment of the present invention, it is illustrated and described that one N-phase busbar (114), which is a neutral line, is provided, but two or more N-phase busbars (114) may be provided.

[0056] Additionally, a pair of grounding wires (130) may be additionally provided within the above-mentioned case.

[0057] Here, a busbar connection hole (161) may be formed in the outer case (120) to expose a busbar (110) to be electrically connected to the branch device (200) to the outside at a portion where the branch device (200) is connected, and a cover (162) for opening and closing the busbar connection hole (161) may be provided.

[0058] In addition, the bus duct connection part (140) connecting the plurality of bus ducts (100a, 100b) may include a connection kit (141) that connects a plurality of bus bars (110) exposed at one end of one bus duct (100a) and a plurality of bus bars (110) exposed at the opposite end of another bus duct (100b) in phases, a cover (142) for protecting the exposed bus bars and the connection kit (141), etc. The connection kit (141) is known in many documents, including the applicant's prior patents, and thus a detailed description thereof will be omitted.

[0059] In addition, the branch device (200) may include a housing (220) equipped with an openable cover, a circuit breaker (230) for preventing overcurrent for safety, etc., and some components of the electric vehicle charger may be provided as an integral part inside the housing (220).

[0060] FIG. 4 is a perspective view of the bottom of a branch device in the bus duct system for charging electric vehicles illustrated in FIG. 2, FIG. 5 is an enlarged view of a branch connection part provided on the bottom of a branch device generally used in a bus duct connecting to a bus bar, FIGS. 6 and 7 are enlarged views of a branch connection part provided on the bottom of a branch device according to an embodiment of the present invention connecting to a bus bar, FIG. 8 is a schematic view of an embodiment of a state of an electrical connecting member arranged under a circuit breaker in a state where the cover of the housing is opened and the circuit breaker is removed in each of the branch devices illustrated in FIG. 2, and FIG. 9 is a schematic view of a power supply route in an electric vehicle charging system including the bus duct system for charging electric vehicles illustrated in FIG. 2.

[0061] Specifically, the branch device (200) may include a branch connection portion (210) on the lower surface for electrically connecting a plurality of busbars (110) exposed to the outside through busbar connection holes (161) in the outer case (120) of the bus duct (100a, 100b) at a portion where the branch device (200) is fastened and the circuit breaker (230).

[0062] Here, the branch connection portion (210) may include a plurality of electrical connection members (212) having, for example, a clamp shape so as to be able to grip both sides of each busbar to connect to each of the plurality of busbars (110), and a branch connection housing (211) into which each of the plurality of electrical connection members (212) is detachably inserted and protected and insulated.

[0063] Each of the plurality of electrical connecting members (212) may be directly connected to each of the plurality of busbars (110), but may also be electrically connected to each of the plurality of busbars (110) through a connecting terminal coupled to each of the plurality of busbars (110).

[0064] As illustrated in FIG. 5, the branch connection part (210) provided on the lower surface of the branch device (200) generally used in the bus duct (100) branches the power into three phases by electrically connecting each of the plurality of electrical connection members (212) to each of the R-phase, S-phase, T-phase and N-phase bus bars (111, 112, 113, 114) and then supplies the power back to the electric vehicle charger through a separate distribution board. However, according to an embodiment of the bus duct system for electric vehicle charging of the present invention, as illustrated in FIG. 6, the electrical connection member (212) includes one of the R-phase, S-phase and T-phase bus bars (111, 112, 113), for example, a first electrical connection member (212a) connected to the R-phase bus bar (111) and a second electrical connection member (212b) connected to the N-phase bus bar (114), and the plurality of electrical connection members (212) are connected to each other. The connecting member (212) electrically connects only one of the R-phase, S-phase, and T-phase busbars (111, 112, 113) and the N-phase busbar (114), thereby supplying power to the electric vehicle charger (600) in a single phase rather than in multiple phases such as three phases.

[0065] Alternatively, the bus duct system for charging an electric vehicle of the present invention may have a connection terminal (150) such as a tab bar extended from each of the R-phase, S-phase, and T-phase bus bars (111, 112, 113) and the N-phase bus bar (114) as illustrated in FIG. 7, connected to an electrical connection member (212). In this case, the bus bar from which the connection terminal (150) is not extended is not connected to the electrical connection member (212), thereby supplying power to the electric vehicle charger (600) by branching it into a single phase.

[0066] Accordingly, in the bus duct system for charging electric vehicles of the present invention, only one of the R-phase, S-phase, and T-phase busbars (111, 112, 113) is electrically connected to the first electrical connecting member (212a), and the N-phase busbar (114) is electrically connected to the second electrical connecting member (212b), so that the plurality of electrical connecting members (210) are electrically connected only to one of the R-phase, S-phase, and T-phase busbars (111, 112, 113) and the N-phase busbar (114).

[0067] For example, in the first branch device (200a) illustrated in FIG. 9, as illustrated in FIG. 8a, the first electrical connection member (212a) is connected only to the R-phase busbar (111) among the R-phase, S-phase, and T-phase busbars (111, 112, 113), and the second electrical connection member (212b) is connected to the N-phase busbar (114), so that the branched power is supplied to the first electric vehicle charger (600a), and in the second branch device (200b), as illustrated in FIG. 8b, the first electrical connection member (212a) is connected only to the S-phase busbar (112) among the R-phase, S-phase, and T-phase busbars (111, 112, 113), and the second electrical connection member (212b) is connected to the N-phase busbar (114), so that the branched power is supplied to the second electric vehicle charger (600b), and the third In the branch device (200c), as shown in Fig. 8c, among the R-phase, S-phase, and T-phase busbars (111, 112, 113), the first electrical connecting member (212a) is connected only to the T-phase busbar (113), and the second electrical connecting member (212b) is connected to the N-phase busbar (114), so that the branched power can be supplied to the third electric vehicle charger (600c).

[0068] Accordingly, since power is supplied to each electric vehicle charger (600) in a single phase through the branch device (200), a distribution panel for redistributing the power that has been branched into multiple phases such as three phases is unnecessary, so the space required for constructing a charging facility is minimized, and the power supply route is simplified, thereby reducing the possibility of a power supply error.

[0069] In particular, the bus duct system for charging electric vehicles according to the present invention can be equipped with N branch devices (200) throughout the bus duct line, and when the number of branch devices including a first electrical connection member (212a) connected to an R-phase bus bar (111) among the N branch devices is X, the number of branch devices including a first electrical connection member (212a) connected to an S-phase bus bar (112) is Y, and the number of branch devices including a first electrical connection member (212c) connected to a T-phase bus bar (113) is Z, the phase balance of the entire bus duct line can be implemented by satisfying the following mathematical expression 1, so that efficient power supply can be implemented.

[0070] [Mathematical Formula 1]

[0071] 3(C max -C min ) / N ≤ 0.25

[0072] In the above mathematical expression 1, C max is the largest value among X, Y and Z, and C min is the smallest value among X, Y, and Z.

[0073] Here, if the bus duct system for charging an electric vehicle according to the present invention does not satisfy the above mathematical expression 1, excessive current may flow to the N-phase busbar, which is the neutral line, causing a circuit failure, and further, since the current is concentrated on one phase busbar, a voltage drop may become severe, heat may be generated, and a circuit breaker may be operated, resulting in an inefficient power supply problem.

[0074] Meanwhile, the R-phase busbar (111) may be called the L1-phase busbar, the S-phase busbar (112) may be called the L2-phase busbar, and the T-phase busbar (113) may be called the L3-phase busbar.

[0075] Figure 10 schematically illustrates the configuration of an electric vehicle charging system with an additional configuration of a cable reel structure according to the present invention.

[0076] As illustrated in FIG. 10, in the electric vehicle charging system according to the present invention, the electric vehicle charger (600) may include a charging unit that provides charging power to the electric vehicle, an electric vehicle connection unit made of a charging cable or a wireless charging coil to connect the charging unit and the electric vehicle wired or wirelessly, a control unit that controls the charging unit, etc. Specifically, the charging unit may receive power from the branch device (200) and perform charging of the electric vehicle through the electric vehicle connection unit according to a signal received from the control unit.

[0077] In addition, the electric vehicle charger (600) may be connected to the bus duct line (100) separately from the branch device (200), or some of the components of the electric vehicle charger (600), for example, the charging unit, may be integrally provided within the housing of the branch device (200).

[0078] Here, when the electric vehicle connection part is formed of a wireless charging coil, the wireless charging coil may be a transmission coil and the electric vehicle may be equipped with a reception coil. For example, the transmission coil may be placed on the ground of a place where the electric vehicle is parked, and the reception coil may be placed on the lower surface of the electric vehicle, so that when the electric vehicle is parked, the transmission coil and the reception coil face each other, and a current flows to the reception coil by electromagnetic induction, thereby charging the battery inside the electric vehicle.

[0079] Meanwhile, if the electric vehicle connection part is made of a wired charging cable, a cable reel structure (300, 400) capable of winding and pulling out or pulling in the cable to adjust the length of the cable may be additionally connected to the bus duct line (100). Here, the cable reel structure may be applied by selecting a single reel structure (300) having one pulley on which the cable is wound, or a double reel structure (400) having two pulleys.

[0080] Specifically, the connection made of a wired charging cable may include a first cable (510a) that is introduced into the single-reel structure (300) from the electric vehicle charger and a second cable (510b) that is drawn out from the single-reel structure (300) and connected to the electric vehicle. In addition, the connection made of a wired charging cable may include a cable (520) that is introduced into and drawn out from the double-reel structure (400) from the electric vehicle charger.

[0081] Fig. 11 is an enlarged view of the configuration of a single-reel structure among the cable reel structures illustrated in Fig. 10. Specifically, Fig. 11a is a perspective view of the single-reel structure, and Fig. 11b is an enlarged view of only the flange of the single-reel structure illustrated in Fig. 11a. In addition, Fig. 12 is an enlarged internal perspective view of only the slip ring of the single-reel structure illustrated in Fig. 11a.

[0082] As illustrated in FIG. 11, the single-reel structure may include a 'ㄷ'-shaped base plate (310) that can be fastened to the bus duct line (100), a pulley (320) that can rotate around an axis penetrating the base plate (310) and on which a cable can be wound, a slip ring (330) coupled to the pulley (320), etc.

[0083] Specifically, as illustrated in FIGS. 11 and 12, the first cable (510a) is electrically connected to a brush (333) inside the slip ring (330) through a first connecting portion (331) at one end of the shaft, the brush (333) is electrically connected to a coil wound around a rotor (334) inside the slip ring (330), and the coil is electrically connected to a second cable (510b) wound around the pulley (320) through a second connecting portion (332), so that the first cable (510a) and the second cable (510b) are electrically connected.

[0084] Accordingly, when the second cable (510b) wound around the pulley (320) is pulled out to connect the second cable (510b) to the electric vehicle, the twist and tension applied to the second cable (510b) are offset by the rotation axis around which the rotor (334) rotates being tilted within a certain angle range, and are not transmitted to the first cable (510a), so that the first cable (510a) and the second cable (510b) can be prevented from being damaged.

[0085] In addition, the second cable (510b) can be stably pulled out and pulled in from the pulley (320) by being supported by a support (311) provided at one end of the base plate (310).

[0086] In addition, the pulley (320) has a structure in which a pair of flanges (321, 322) are provided on both sides of a cylinder (323) disposed at the center, so that the second cable (510b) can be wound in a manner of being stacked around the cylinder (323) while being supported by the pair of flanges (321, 322).

[0087] Furthermore, when charging an electric vehicle, the temperature of the second cable (510b) rises, and in order to increase the transmission capacity of the second cable (510b) through effective heat dissipation, as shown in FIG. 2b, the flange (321, 322) may be provided with one or more ventilation holes (321a), and further, the cylinder (323) and the flange (321, 322) may be made of a metal with high thermal conductivity, for example, copper, aluminum, or an alloy thereof.

[0088] Specifically, among the second cables (510b) laminated around the cylinder (323), the lowest layer in direct contact with the cylinder (323) dissipates heat by conduction to the cylinder (323) which has high thermal conductivity, whereas two or more layers laminated on the lowest layer and thus not in direct contact with the cylinder (323) have insufficient heat dissipation, which may limit the transmission capacity of the second cable (510b), and the second cable (510b) may be damaged, the user may be burned, or a fire may occur.

[0089] Accordingly, additional heat dissipation can be performed by contact between a portion disposed in two or more layers of the laminated structure of the second cable (510b) and external air through one or more ventilation holes (321a) provided in the flange (321, 322), and preferably, the ventilation holes (321a) can be arranged adjacent to a portion disposed in two or more layers, more preferably in three or more layers, of the second cable (510b), and the total cross-sectional area of ​​the one or more ventilation holes (321a) can occupy 30 to 70% based on the cross-sectional area of ​​the flange (321, 322).

[0090] Here, if the total cross-sectional area of ​​the ventilation hole (321a) is less than 30% of the cross-sectional area of ​​the flange (321, 322), contact between the second cable (510b) and the outside air and heat dissipation thereby are insufficient, which may result in a reduction in the transmission capacity of the second cable (510b), damage to the cable, burns to the user, or a fire, while if it exceeds 70%, the rigidity of the flange (321, 322) is insufficient, making it impossible to stably support the second cable (510b).

[0091] In addition, a spring member (not shown) such as a mainspring may be provided inside the pulley (320) that can rotate around an axis penetrating the base plate (310). In the process of pulling out the second cable (510b) wound around the pulley (320) to connect the second cable (510b) to the electric vehicle, the pulley (320) rotates in one direction, and accordingly, elasticity is stored in the spring member, and when the second cable (510b) is separated from the electric vehicle upon completion of charging of the electric vehicle, the pulley (320) automatically rotates in the other direction by the elasticity stored in the spring member, so that the second cable (510b) can be wound around the pulley (320) again.

[0092] However, when the second cable (510b) is wound again on the pulley (320) by the elasticity of the spring member, if the winding speed is too fast, the second cable (510b) may be damaged or it may be difficult to wind it stably on the pulley (320), so it is necessary to control the winding speed.

[0093] Fig. 13 schematically illustrates a speed controller applicable to the single-reel structure illustrated in Fig. 11.

[0094] As illustrated in Fig. 13, a speed controller (340) is additionally provided in the single-reel structure (300), so that the speed at which the pulley (320) rotates in the other direction, i.e., the speed at which the pulley (320) rotates when the second cable (510b) is wound around the pulley (320), can be controlled.

[0095] Specifically, the speed controller (340) may include a gear (341) that is rotatable with the pulley (320) about the same central axis as the pulley (320) and has teeth protruding on its periphery, a support rod (342) that is arranged adjacent to the gear (341) and is rotatable about the central axis so that one end moves along the surface of the teeth provided on the periphery of the gear when the gear rotates, and a linear damper (343) that suppresses the rise of the end of the support rod (342) that is arranged far from the gear (341).

[0096] Here, the gear (341) may be separately provided on the base plate (310) and the pulley (320), and one of the pair of flanges (321, 322) of the pulley (320) may be provided as a gear.

[0097] Accordingly, as shown in Fig. 13a, when the second cable (510b) is pulled out, when the gear (341) rotates in the direction in which the pulley (320) rotates, i.e., counterclockwise, one end of the support bar (342) moves along the surface of the teeth provided around the gear (341), and the other end of the support bar (342) descends without much resistance.

[0098] On the other hand, as shown in FIG. 13b, when the second cable (510b) is introduced, when the gear (341) rotates in the direction in which the pulley (320) rotates, i.e., clockwise, one end of the support rod (342) moves along the surface of the teeth provided around the gear (341), and the other end of the support rod (342) rises, and the linear damper (343) suppresses the rise of the other end of the rising support rod (342), thereby slowing down the rotational speed of the gear (341) and the rotational speed of the pulley (320) that rotates together with the gear (341), and consequently slowing down the speed at which the second cable (510b) is wound around the pulley (320).

[0099] Fig. 14 schematically illustrates a magnetic damper applicable to the single-reel structure illustrated in Fig. 11.

[0100] As illustrated in Fig. 14, the single-reel structure (300) may be provided with a magnetic damper (350) as the speed controller, replacing the speed controller (340). The magnetic damper (350) may include a magnetic stator (351) that does not rotate and has one or more permanent magnets (351a) on its surface, a magnetic rotor (352) that rotates and has one or more permanent magnets (352a) on its surface, a partition (353) provided between the magnetic stator (351) and the magnetic rotor (352) and having a plurality of openable and closable shutters (353a), a rotational shaft (354) connecting the magnetic stator (351), the magnetic rotor (352), and the partition (353).

[0101] Specifically, the permanent magnet (351a) provided in the magnetic stator (351) and the permanent magnet (352a) provided in the magnetic rotor (352) may face each other and have the same or opposite polarities, and the magnetic stator (351) may be fixed to the base plate (310), and the magnetic rotor (352) and the partition (353) may rotate together with the pulley (320).

[0102] Accordingly, when the partition (353) rotates in the direction in which the pulley (320) rotates when the second cable (510b) is pulled out, all of the plurality of shutters (353a) provided in the partition (353) are closed and block the space between the permanent magnet (351a) of the magnetic stator (351) and the permanent magnet (352a) of the magnetic rotor (352), so that the magnetic rotor (352) and the partition (353) rotate without much resistance without any attractive or repulsive force between the permanent magnets, and accordingly, the pulley (320) also rotates without much resistance, so that the second cable (510b) can be easily pulled out.

[0103] On the other hand, when the partition (353) rotates in the direction in which the pulley (320) rotates when the second cable (510b) is introduced, as the degree or number of rotations increases, a plurality of shutters (353a) are sequentially opened gradually, and an attractive force or a repulsive force between the permanent magnets (351a, 352a) is applied through the empty space blocked by the shutters (353a), and as a result, the rotation of the magnetic rotor (352) and the partition (353) is resisted, and the rotation speed is reduced, and accordingly, the pulley (320) is also resisted, and the rotation speed is reduced, and as a result, the winding speed of the second cable (510b) is reduced.

[0104] Fig. 15 schematically illustrates the laminated structure of a cable wound on a pulley of the single-reel structure illustrated in Fig. 11.

[0105] As illustrated in FIG. 15, the gap between a pair of flanges (321, 322) constituting the pulley (320), i.e., the width (w) of the cylinder (323) provided between the pair of flanges (321, 322), may be 1.5 to 2.5 times the diameter (D) of the second cable (510b) wound around the pulley (320).

[0106] Here, if the width (w) is less than 1.5 times the diameter (D), the diameter must increase in order to stably support the second cable (510b) on which the flange (321, 322) is wound, and accordingly, the weight of the single-reel structure (300) increases, and as a result, a problem may arise in which an excessive load is applied to the bus duct line (100) to which the single-reel structure (300) is connected.

[0107] On the other hand, if the width (w) is more than 2.5 times the diameter (D), a problem in heat dissipation may occur as the portion arranged horizontally in each layer of the laminated structure of the first cable (510b) increases, so that the transmission capacity of the first cable (510b) may decrease, and the cable may be damaged, the user may be burned, or a fire may occur.

[0108] Fig. 16 schematically illustrates the configuration of a double reel structure among the cable reel structures illustrated in Fig. 10, and Fig. 17 is an enlarged view of the double reel structure illustrated in Fig. 16.

[0109] As illustrated in FIGS. 16 and 17, the double-reel structure (400) includes a pair of pulleys (410, 420) around which a cable (520) is wound and arranged in a row on a frame (440), and among the pair of pulleys (410, 420), the first pulley (410) arranged adjacent to the electric vehicle charger has a fixed central axis about which the first pulley (410) rotates, while the other second pulley (420) has a central axis about which the first pulley (410) rotates that is movable horizontally along the frame (440).

[0110] Additionally, the second pulley (420) may include a recovery part (430) such as a roll spring having elasticity that pulls the second pulley (420) away from the first pulley (410).

[0111] Accordingly, when a user pulls the cable (520) out from the first pulley (410) to connect the cable (520) to the electric vehicle, the first pulley (410) and the second pulley (420) rotate, and at the same time, the second pulley (420) moves horizontally in a direction closer to the first pulley (410), and elasticity is stored in the roll spring connected to the second pulley (420).

[0112] On the other hand, when the user removes the pulling force after detaching the cable (520) from the electric vehicle, the second pulley (420) is pulled away from the first pulley (410) by the elasticity stored in the roll spring (430), and as a result, the first pulley (410) and the second pulley (420) are further separated from each other, and the cable (520) is recovered. Here, a roll spring such as a spring is also provided inside the second pulley (420), so that when the second pulley (420) is pulled away from the first pulley (410), the second pulley (420) rotates on its own, thereby further accelerating the recovery of the cable (520).

[0113] Fig. 18 is a schematic diagram of a cross-section of a pulley around which a cable is wound in the double-reel structure illustrated in Fig. 17.

[0114] As illustrated in Fig. 18, the first pulley (410) may be provided with a plurality of discs (411, 412, 413) connected to the same central axis but capable of rotating separately, and a cable (520) may be wound around each disc (411, 412, 413). The same applies to the second pulley (420).

[0115] As described above, when the cable (520) is introduced or withdrawn from the double-reel structure (400), the second pulley (420) moves horizontally, and as a result, the degree of rotation of each of the plates (411, 412, 413), i.e., the rotation angle and the number of rotations, become different. Therefore, each of the plates (411, 412, 413) must be able to rotate separately. If each of the plates (411, 412, 413) rotates to the same degree, the cable (520) may be damaged due to friction between some of the plates and the cable (520) wound thereon, or the introduction or withdrawal of the cable (520) may be difficult.

[0116] In addition, a groove may be formed around the circumference of the circular plate (411, 412, 413) to minimize friction between the circular plate (411, 412, 413) and the cable (520) wound around it. Specifically, by winding the cable (520) around the groove, the contact area between the circumference of the circular plate (411, 412, 413) and the cable is minimized, and as a result, friction between them is minimized, thereby preventing damage to the cable (520) due to friction and enabling smoother insertion or withdrawal of the cable (520).

[0117] In addition, the diameter of the pulley (410, 420) may be designed to be 10 times or more based on the diameter of the cable (520) wound around the pulley (410, 420). If the diameter of the pulley (410, 420) is less than 10 times based on the diameter of the cable (520) wound around the pulley (410, 420), the friction between the circumferential surface of the pulley (410, 420) and the cable (520) increases, and when the cable (520) is pulled in or out, a cable lifting phenomenon may occur in which the cable (520) between the pulleys (410, 420) sags down or rises up.

[0118] Furthermore, the pulley (410, 420), for example, at least one of the plurality of discs constituting the pulley (410, 420), may be made of a material having a low coefficient of friction, for example, polyacetal resin, to minimize friction with the cable (520). The polyacetal resin has excellent wear resistance and a low coefficient of friction, which can further improve the rolling characteristics of the pulley (410, 420).

[0119] Figure 19 is an enlarged view of the ratchet stopper in Figure 17.

[0120] As illustrated in FIG. 19, the double reel structure (400) may be provided with a stopper, particularly a ratchet stopper (450), that fixes a cable (520) pulled out by a user in a pulled-out state.

[0121] As described above, when a user pulls the cable (520) from the pulley (410, 420) to connect the cable (520) to an electric vehicle, the second pulley (420) moves horizontally toward the first pulley (410), and elasticity is stored in the recovery part (430) such as a roll spring, and due to this elasticity, the cable (520) receives a tensile force so that it is wound around the pulley (410, 420) again and recovered.

[0122] That is, when the charging of the electric vehicle is completed and the user wants to disconnect the cable (520) from the electric vehicle, it may be difficult to disconnect the cable (520) that is under continuous tensile force, and in particular, when the cable (520) is quickly withdrawn by the tensile force immediately after disconnecting the cable (520) from the electric vehicle, the cable (520) or the connector provided at the end thereof may be damaged, or the cable (520) or the connector may collide with the user, resulting in injury to the user.

[0123] Accordingly, the ratchet stopper (450) performs a function of forcibly stopping the rotation of the pulley (410, 420) around which the cable (520) is wound so that the cable (520) is no longer subjected to tensile force by the recovery unit (430) while connected to the electric vehicle, thereby preventing the cable (520) from being recovered at high speed immediately after the cable (520) is separated from the electric vehicle.

[0124] Specifically, the ratchet stopper (450) may include a ratchet wheel (451) and a latch (452), and asymmetrical teeth are formed around the periphery of the ratchet wheel (451), and the latch (452) is positioned over the teeth.

[0125] Accordingly, as illustrated in FIG. 19a, the ratchet wheel (451) can rotate counterclockwise, but as illustrated in FIG. 19b, when the ratchet wheel (451) attempts to rotate clockwise, the teeth are caught by the latch (452), making it impossible to rotate. Here, the possible and impossible rotational directions can be changed depending on the shape of the teeth of the ratchet wheel (451). That is, due to the latch (452), the ratchet wheel (451) can rotate only in one direction, either clockwise or counterclockwise.

[0126] In particular, the ratchet stopper (450) may be provided on, for example, the first pulley (410) and may move integrally with the first pulley (410), and when a user pulls the cable (520) to connect it to an electric vehicle, the pulley (410, 420) around which the cable (520) is wound rotates counterclockwise and the cable (520) is pulled out, but since the first pulley (410) cannot rotate clockwise by the ratchet stopper (450), the pulled-out cable (520) is not automatically pulled back in.

[0127] Meanwhile, the ratchet wheel (451) may be provided with one or more grooves (451a), preferably a pair of grooves (451a) may be provided symmetrically to each other, and no teeth are formed on the grooves (451a). Accordingly, the latch (452) is structured so that it cannot be caught on the teeth of the grooves (451a), and once the latch (452) is positioned on the grooves (415) as shown in FIG. 19c, the ratchet wheel (451) can be rotated clockwise as shown in FIG. 19d.

[0128] That is, the user can select whether the ratchet wheel (451) can rotate clockwise through the ratchet stopper (450), i.e., whether the cable (520) can be automatically withdrawn. Specifically, the user pulls the cable (520) to connect it to the electric vehicle, and when the cable is withdrawn, the pulleys (410, 420) rotate counterclockwise, and when the latch (452) engages the teeth as shown in FIG. 19b, the cable (520) is fixed in the withdrawn state, and the cable (520) is connected to the electric vehicle to charge the electric vehicle.

[0129] In addition, when the charging of the electric vehicle is completed, the user withdraws the cable (520) again and releases the cable (520) while the latch (452) is positioned in the groove (415a) as shown in FIG. 19c, and the ratchet wheel (451) rotates clockwise as shown in FIG. 19d due to the tensile force caused by the elasticity of the recovery part (430), and the pulleys (410, 420) that operate integrally with the ratchet wheel (451) also rotate clockwise, allowing the cable (520) to be stably recovered.

[0130] In particular, when the ratchet wheel (451) rotates clockwise as shown in FIG. 19d, the latch (452) rubs against the teeth formed around the ratchet wheel (451), and this friction slows down the rotation speed of the ratchet wheel (451) and the first pulley (410) that moves integrally with the ratchet wheel (451), thereby preventing the cable (520) from being recovered at high speed.

[0131] Fig. 20 is an exploded perspective view of a ball bearing stopper applicable to the cable reel structure illustrated in Fig. 10, Fig. 21 schematically illustrates the operation of the ball bearing stopper in Fig. 20, and Fig. 22 schematically illustrates another operation of the ball bearing stopper in Fig. 20.

[0132] The single reel structure of FIG. 11 or the double reel structure of FIG. 16 may be provided with a ball bearing stopper (460) that can fix the exposed length of a cable wound on the single reel structure or the double reel structure and control the pulling speed when the cable is pulled in. For example, the ball bearing stopper (460) may be fixed to the base plate (310) of the single reel structure or the frame (440) of the double reel structure.

[0133] As illustrated in FIG. 20, the ball bearing stopper (460) may be provided with a groove (461) disposed at the top inside a cylindrical housing (463) and rotatable in one direction, for example, counterclockwise, and a protrusion (462) disposed at the bottom and movable up and down, and the cylindrical housing (463) may have an upper cover (464) fastened to the top and a lower cover (465) fastened to the bottom, thereby preventing the groove (461) and the protrusion (462) inside the cylindrical housing (463) from coming off.

[0134] Here, the groove (461) has a hollow hole inside through which a cable can pass, and a long-axis groove (461a), an inclined surface (461c), and a short-axis groove (461b) can be sequentially and repeatedly arranged at the bottom of the circumference of the hollow hole, and the protrusion (462) has a hollow hole inside through which a cable can pass, and one or more protruding columns (462a) are provided at the top of the circumference of the hollow hole, and one or more balls (462b) capable of horizontal movement of a certain length can be provided at the bottom.

[0135] Accordingly, the cable passes through the hollow hole of the groove (461) positioned at the top and the protrusion (462) positioned at the bottom inside the cylindrical housing (463), and when the user pulls the cable downward with a strong force to use it in this state, the protrusion (462) moves downward together with the cable, and the groove (461) rotates counterclockwise, so that the protrusion pillar (462a) of the protrusion (462) is inserted into the short groove (461b) of the groove (461) and fixed, as shown in FIG. 21.

[0136] In this state, one or more balls (462b) provided at the lower portion of the protrusion (462) wrap around the cable penetrating the hollow hole and are in contact with or adjacent to the cable surface, but since the space inside the housing is sufficient at the position of the balls (462b), the balls (462b) do not press strongly or do not press at all around the cable, so that the cable can move freely up and down, and when the user does not hold the cable, an upward tensile force is applied by the elasticity of the single reel recovery part of the single reel structure (300) or the double reel recovery part (430) of the double reel structure (400), so that the cable can move upward and be recovered.

[0137] Meanwhile, when the user momentarily pulls the cable downward with a somewhat strong force, the protrusion (462) momentarily moves downward, causing the protrusion column (462a) to come out of the short-axis groove (461b), and at the same time, the groove (461) rotates slightly counterclockwise, and as shown in FIG. 22, the protrusion column (462a) is inserted into the long-axis groove (461a).

[0138] In this state, the ball (462b) at the bottom of the protrusion (462) is positioned higher than the position in the state shown in Fig. 21, that is, the position in the state in which the protrusion pillar (462a) is inserted into the short groove (461b), and in this position, the space inside the housing is reduced, and thus the ball (462b) relatively strongly presses the circumference of the cable to suppress the up-and-down movement of the cable.

[0139] Accordingly, the initial state of the ball bearing stopper (460) is as shown in Fig. 22, in which the protruding pillar (462a) of the protruding portion (462) is inserted into the long-axis groove (461a) of the groove portion (461), and the ball (462b) at the bottom of the protruding portion (462) presses the cable passing through the hollow hole from the circumference to suppress the up-and-down movement of the cable.

[0140] In addition, when the user wants to pull down to use the cable, if he pulls down with a strong force momentarily, the protrusion (462) moves downward momentarily and the groove (461) rotates counterclockwise, and as shown in FIG. 13, the protrusion pillar (462a) comes out of the long-axis groove (461a) and is inserted into the short-axis groove (461b), and in this state, the user can freely pull down to pull out the cable and use it, such as by connecting the cable to an electric vehicle.

[0141] And, in order to remove the tensile force applied to the cable immediately before or immediately after using the cable, the user pulls the cable downwards with a strong force once again, so that the protrusion (462) moves downward momentarily and the groove (461) rotates counterclockwise, and as shown in FIG. 22, the protrusion column (462a) comes out of the short-axis groove (461b) and is inserted back into the long-axis groove (461a), and in this state, one or more balls (462b) provided at the lower end of the protrusion (462) press the cable around to suppress the cable from moving up and down.

[0142] Finally, when the cable is finished being used and needs to be retrieved, the user pulls the cable down again with a strong force, so that the protrusion (462) moves downward momentarily and the groove (461) rotates counterclockwise, and as shown in FIG. 21, the protrusion column (462a) comes out of the long-axis groove (461a) and is inserted into the short-axis groove (461b). In this state, when the user releases the cable, the single-reel recovery part of the single-reel structure (300) or the double-reel recovery part (430) of the double-reel structure (400) pulls and retrieves the cable by the stored elasticity.

[0143] Here, the counterclockwise rotation of the groove (461) can be replaced with a clockwise rotation depending on the arrangement of the long-axis groove (461a) and the short-axis groove (461b) of the groove (461), and the rotation of the groove (461) can be performed manually by the user or automatically by a sub-ball bearing additionally provided in the housing.

[0144] Fig. 23 schematically illustrates the operation of the sub-ball bearing in the ball bearing stopper illustrated in Fig. 20.

[0145] As shown in Fig. 23, the sub ball bearing (463a) additionally provided in the housing can perform the function of pushing the groove (461) clockwise or counterclockwise in a state where the protruding column (462a) of the protruding portion (462) is inserted into the long-axis groove (461a) or short-axis groove (461b) of the groove (461).

[0146] Specifically, as shown in Fig. 23a, in a state where the protruding pillar (462a) of the protruding portion (462) is inserted into the longitudinal groove (461a) of the groove portion (461), the sub ball bearing (463a) is provided in the groove portion (461) and includes a plurality of protruding portions and an inclined surface between adjacent protruding portions, and is placed on an inclined surface adjacent to the first position between the protruding position 1 and the protruding position 2, thereby applying a force to rotate the protruding portion (461d) counterclockwise.

[0147] Next, as shown in FIG. 23b, when the protrusion (462) is lowered and separated from the groove (461), the groove (461) is slightly rotated counterclockwise by the pressing force of the sub ball bearing (463a), so that the protrusion pillar (462a) of the protrusion (462) moves from the long axis groove (461a) and enters the short axis groove (461b) adjacent to the long axis groove (461a), and here, the sub ball bearing (463a) is positioned at the most depressed portion between the 1st and 2nd positions of the uneven portion (461d).

[0148] And, as shown in Fig. 23c, the protruding column (462a) that has entered the short-cut groove (461b) is inserted into the short-cut groove (461d) while the inclined surface formed on the upper portion slides on the inclined surface formed in the short-cut groove (461b), and in this process, the sub-ball bearing (463a) is placed on the inclined surface adjacent to the second position between the protruding position 2 and the protruding position 3 in the protruding portion (461d) and presses, thereby applying a force to rotate the protruding portion (461d) counterclockwise.

[0149] Next, as shown in FIG. 23d, when the protrusion (462) is lowered and separated from the groove (461), the groove (461) is slightly rotated counterclockwise by the pressing force of the sub ball bearing (463a), so that the protruding column (462a) of the protrusion (462) moves from the short groove (461b) and enters the inclined surface (461c) adjacent to the short groove (461a), where the sub ball bearing (463a) is positioned at the most depressed portion between the 2nd and 3rd positions in the uneven portion (461d).

[0150] Finally, as shown in Fig. 23e, the protruding column (462a) that has entered the inclined surface (461c) is inserted into the long-axis groove (461d) again while the inclined surface formed on the upper portion slides on the inclined surface (461c), and in this process, the sub ball bearing (463a) is placed on the inclined surface adjacent to the 3rd position between the protruding position 3 and the protruding position 4 from the uneven portion (461d) and presses it, thereby applying a force to rotate the uneven portion (461d) counterclockwise.

[0151] That is, in this process, while the protrusion (462) repeats rising and falling, the groove (461) continuously rotates slightly counterclockwise or clockwise to adjust the position of the protrusion (462), thereby allowing the ball bearing (462b) of the protrusion (462) to be repeatedly fixed and released from the cable penetrating the internal hollow portion.

[0152]

[0153] [Example]

[0154]

[0155] 1. Equilibrium evaluation

[0156]

[0157] The phase equilibrium was evaluated under the conditions described in Table 1 below with a total load of 281.6 kW and a load of 6.4 kW in a bus duct line with a total of 44 branch boxes connected to each bus duct, and the evaluation results are as described in Table 2 below.

[0158]

[0159] Example 1 Example 2 Example 3 Load Capacity (kW) Load Capacity (kW) Load Capacity (kW) A (RN) 1489.6 1596 17 108.8 B (SN) 1596 1383.2 16 102.4 C (TN) 1596 16 102.4 1170.4

[0160] Example 1 Example 2 Example 3 3 (Cmax - Cmin) / N 0.0076 0.2046 0.409 1A-B Load capacity difference 6.41 2.86.4 BC Load capacity difference 0 19.232 CA Load capacity difference 6.46.43 8.4 D (maximum value of load capacity difference) 6.41 9.23 8.4 E (total load / 3) 93.99 3.99 3.9 Load unbalance ratio (D / E*100) (%) 6.82 0.540

[0161]

[0162] As described in Table 2 above, the bus duct lines of Examples 1 and 2 that satisfy Mathematical Formula 1 can perform efficient power supply with a load unbalance ratio of 30% or less between the R-phase, S-phase, and T-phase busbars, whereas the bus duct line of Example 3 that does not satisfy Mathematical Formula 1 has a load unbalance ratio exceeding 30%, which may cause circuit failure due to excessive current in the neutral line, and may cause inefficient power supply such as severe voltage drop and circuit breaker operation due to current concentration in one phase. Here, the load unbalance ratio (unit: %) can be calculated by (D / E*100) as in the equation in Table 2.

[0163] While the present invention has been described above with reference to one embodiment, those skilled in the art will appreciate that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention as defined in the claims below. Therefore, any modified implementation that fundamentally includes the elements of the claims should be considered within the technical scope of the present invention.

Claims

1. As a bus duct system for electric vehicle charging, A bus duct line constituting a power supply network, including a bus duct connection that electrically connects a plurality of bus ducts and bus ducts; and It includes a branch device that branches the power supplied through the above bus duct and supplies power to an electric vehicle charger, The above bus duct includes a plurality of bus bars and an enclosure that accommodates the plurality of bus bars, The above plurality of busbars include R-phase, S-phase, T-phase and at least one N-phase busbar, The above branch device includes a plurality of electrical connecting members electrically connected one-to-one with the plurality of busbars, a first electrical connecting member connected to one of the R-phase, S-phase, and T-phase busbars, and a second electrical connecting member connected to the N-phase busbar. A bus duct system for charging an electric vehicle, characterized in that the plurality of electrical connecting members are electrically connected only to one of the R-phase, S-phase, and T-phase bus bars and the N-phase bus bar.

2. In paragraph 1, The above branch device is composed of N branch devices across the entire bus duct line, A bus duct system for charging an electric vehicle, characterized in that among the N branch devices, the number of branch devices including a first electrical connection member connected to an R-phase busbar is X, the number of branch devices including a first electrical connection member connected to an S-phase busbar is Y, and the number of branch devices including a first electrical connection member connected to a T-phase busbar is Z, and the system satisfies the following mathematical expression 1. [Mathematical Formula 1] 3(C max -C min ) / N ≤ 0.25 In the above mathematical formula 1, C max is the largest value among X, Y and Z, and C min is the smallest value among X, Y, and Z.

3. In paragraph 1 or 2, A bus duct system for charging an electric vehicle, characterized in that each of the plurality of electrical connecting members is electrically connected to each of the plurality of bus bars through a connecting terminal coupled to each of the plurality of bus bars.

4. Bus duct system for electric vehicle charging according to paragraph 1 or 2; and An electric vehicle charging system, characterized by including an electric vehicle charger for charging an electric vehicle using power supplied from the above branch device.

5. In paragraph 4, An electric vehicle charging system, characterized in that the electric vehicle charger includes a charging unit that provides charging power to an electric vehicle, an electric vehicle connection unit that connects the charging unit and the electric vehicle wired or wirelessly, and a control unit that controls the charging unit.

6. In paragraph 5, An electric vehicle charging system, characterized in that the charging unit is provided inside the branch device.

7. In paragraph 5, An electric vehicle charging system, characterized in that the electric vehicle connection part includes a charging cable or a wireless charging coil.

8. In paragraph 7, The above electric vehicle connection part includes a charging cable, An electric vehicle charging system characterized in that it further includes a cable reel structure capable of pulling out or pulling in the charging cable to adjust the length of the charging cable.

9. In paragraph 8, An electric vehicle charging system, characterized in that the cable reel structure includes a single reel structure having one pulley on which the charging cable is wound or a double reel structure having two pulleys.

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