KR102428540B1 - Pantograph electrode structure suitable for supplying high current and contact resistance measuring method thereof - Google Patents

Abstract

The present invention relates to a pantograph electrode structure and a contact resistance measurement method, specifically, wherein a positive electrode and a negative electrode among feeding electrodes are respectively formed with a plurality of conductors so that each conductor supplies current to receiving electrodes to supply relatively high current so as to charge a large-capacity battery for an electric vehicle. In addition, the present invention relates to the pantograph electrode structure appropriate for supplying high current and the contact resistance measurement method thereof, wherein a contact resistance is calculated by using a current supplied to each conductor and a voltage difference between the conductors, and the calculated contact resistance is used to control and block a charging current or control whether to maintain charging so as to prevent overheating and fire of the electrode.

Description

PANTOGRAPH ELECTRODE STRUCTURE SUITABLE FOR SUPPLYING HIGH CURRENT AND CONTACT RESISTANCE MEASURING METHOD THEREOF

The present invention relates to a structure of a pantograph electrode and a method for measuring contact resistance thereof, and more particularly, by forming a + electrode and a - electrode of a feeding electrode with a plurality of conductors, respectively, supplying a current from each conductor to a receiving electrode to obtain a relatively high current In addition, the present invention calculates the contact resistance using the current supplied to each conductor and the voltage difference between each conductor, and prevents overheating of the electrode by referring to the calculated contact resistance. It relates to a pantograph electrode structure suitable for supplying a large current and a method for measuring contact resistance thereof.

Recently, the demand for electric vehicles such as electric vehicles and electric buses is increasing significantly.

Conventionally, the connector method (eg, the charging gun method or the plug-in connector method) has been mainly used as a connection means between the charger and the electric bus. It is mainly used only up to about 200A because it has to continuously increase and the conductor becomes thicker and the cable becomes clunky, limiting its use. In order to pass a larger current than that, a water-cooled connector that cools the conductor by flowing cooling water instead of thickening the conductor is used. In the case of a water-cooled connector, the current can be used up to about 500A, but it has disadvantages in that the structure is complicated and the price is high.

In particular, in the case of a large electric vehicle such as an electric bus, the pantograph method can be used to pass a larger current. There are bottom-up and top-down types of pantographs. Bottom-up type is a method in which the pantograph is mounted on the roof of an electric bus and rises when charging. way down. If you need to receive power while moving like an electric train or trambus, you have no choice but to use the bottom-up method, but in the case of an electric bus, charging is performed only in a stopped state, so using the top-down method may be more advantageous in cost reduction. The pantograph has the advantage that a large current can flow because the area of the conductor connection is large, and since the cable is fixed, there is no problem even if a thick cable is used if necessary.

As shown in FIG. 1, this top-down pantograph includes an elevating unit 10, an arm 20 that is folded according to the operation of the elevating unit 10, and a feeding electrode 30 installed at the lower end of the arm.

The feeding electrode 30 includes a + electrode 31 , a - electrode 33 , a ground electrode 35 , and a control pilot (CP) electrode 27 .

In addition, as shown in FIG. 2 , the power receiving electrode 40 is a power receiving side + electrode 41 , a receiving side - electrode 43 , a receiving side ground electrode 45 , and a receiving side CP electrode 47 on the roof of the electric vehicle. is provided, and is vertically crossed with the feeding electrode 30 to receive charging power, that is, current.

However, such a top-down pantograph has a maximum current of about 1000A, and as the battery capacity increases, the pantograph current is also greatly required to be 1500-2000A. Meanwhile, as the pantograph current increases, a technology capable of preventing overheating due to the contact resistance of the electrode is also required.

However, in such a top-down pantograph, the feeding electrode and the receiving electrode must be in good contact during charging. As the period of use increases, the contact state between the feeding electrode and the receiving electrode deteriorates, which may increase the contact resistance. When the contact resistance increases, excessive heat is generated at the contact part between the electrodes during charging, and in severe cases, it can lead to a fire. Therefore, it is necessary to prevent contact failure in advance by detecting whether the state of contact between the feeding electrode and the receiving electrode is good.

However, conventionally, a temperature sensor is installed in a pantograph to detect a contact failure, but there is a problem in that it is structurally complicated.

In order to solve this problem, US Patent Publication No. 2019/0193585 is disclosed as a prior patent.

The prior patent is a configuration for monitoring the contact resistance through the auxiliary electrode by configuring the feeding electrode with one main electrode and one auxiliary electrode.

However, this prior patent has a problem in that it cannot supply sufficient charging power because it only monitors the contact resistance and the charging power is supplied through one main electrode.

US Patent Publication No. 2019/0193585

The present invention is to solve the above problems, and by forming the + electrode and the - electrode of the feeding electrode with a plurality of conductors, respectively, a current is supplied from each conductor to the receiving electrode to supply a relatively high current to charge a large-capacity battery. An object of the present invention is to provide a pantograph electrode structure suitable for supplying a large current and a method for measuring contact resistance thereof.

In addition, the present invention calculates the contact resistance using the current supplied to each conductor and the voltage difference between each conductor, and refers to the calculated contact resistance to prevent overheating of the electrode. A pantograph electrode structure suitable for supplying a large current and Another object is to provide a method for measuring contact resistance thereof.

In order to achieve the above object, the pantograph electrode structure suitable for supplying a large current according to the present invention is in contact with a receiving electrode provided in an electric vehicle to supply a current from a charger to the receiving electrode. In the structure, the feeding electrode includes: a + electrode in which a plurality of conductors are spaced apart from each other and each conductor supplies a current to the receiving electrode; A plurality of conductors are disposed to be spaced apart from each other so that each conductor includes a - electrode for supplying a current to the receiving electrode, and the current flowing through the conductor of the + electrode or - electrode before starting charging is individually or according to each conductor. Controlled to be supplied sequentially, each of the contact resistance between the plurality of conductors of the + electrode or the - electrode and the corresponding receiving electrode is the voltage difference between the current flowing through the conductor and the conductor through which the current flows and the other conductor before charging starts. The current flowing through the conductor of the + or - electrode during charging is controlled to be supplied to each conductor, and during charging, the change in contact resistance between each of the plurality of conductors of the + or - electrode and the corresponding receiving electrode is monitored in real time during charging using at least a part of the voltage difference between the current flowing through the conductor during charging and the conductors through which the current flows.

The pantograph electrode structure according to the present invention is disposed between the + electrode and the - electrode and the charger, and a plurality of openings and closings that intermittently control the current flowing through the conductor of the + electrode or the - electrode to be supplied individually or sequentially according to each conductor It is characterized in that it further comprises a switch.

The pantograph electrode structure according to the present invention further comprises a contact resistance calculator for calculating the contact resistance by using the voltage difference between the current supplied to each conductor of the + electrode and the - electrode and each conductor.

The contact resistance calculation unit, when the number of conductors of the + electrode or the - electrode is n (here, n is a natural number greater than or equal to 2), the contact resistance of each conductor (r ₁ , r ₂ , r ₃ , ..., r _n ) can be calculated.

Here, I ₁ , I ₂ , I ₃ , … , I _n is the current flowing through each of the n conductors of the + electrode or - electrode before the start of charging, V ₁ , V ₂ , V ₃ , … , V _n is the voltage applied to each contact resistance between the corresponding conductor and the receiving electrode by the current flowing through each of the n conductors.

Voltage applied to each of the contact resistances V ₁ , V ₂ , V ₃ , … Each of , V _n may be obtained from a voltage difference between a conductor through which the current flows and another conductor.

In order to achieve the above object, the method for measuring contact resistance for a pantograph electrode structure suitable for supplying a large current according to the present invention is a method for measuring contact resistance using a pantograph electrode structure suitable for supplying a large current, before starting charging, the + electrode or - supplying current individually or sequentially to each conductor of the electrode; measuring a voltage applied to each contact resistance between each of a plurality of conductors of the + electrode or - electrode and a corresponding receiving electrode by the current flowing through each of the conductors before charging is started; calculating the contact resistance using a current flowing through each of the conductors and a voltage applied to each of the contact resistances; supplying current to each conductor of the + electrode or - electrode during charging; and using at least a part of the voltage difference between the current flowing through the conductor during charging and the conductors through which the current flows, the change in contact resistance between each of the plurality of conductors of the + electrode or the - electrode and the corresponding receiving electrode during charging in real time It is characterized in that it comprises the step of monitoring.

The step of calculating the contact resistance is, when there are n conductors of the + electrode or the - electrode (where n is a natural number greater than or equal to 2), the contact resistance (r ₁ , r ₂ , r ₃ ) of each conductor by the following equation , …, r _n ) can be calculated.

Here, I ₁ , I ₂ , I ₃ , … , I _n is the current flowing through each of the n conductors of the + electrode or - electrode before the start of charging, V ₁ , V ₂ , V ₃ , … , V _n is the voltage applied to each contact resistance between the corresponding conductor and the receiving electrode by the current flowing through each of the n conductors.

Voltage applied to each of the contact resistances V ₁ , V ₂ , V ₃ , … Each of , V _n may be obtained from a voltage difference between a conductor through which the current flows and another conductor.

According to the present invention, which is a pantograph electrode structure suitable for large current supply and a method for measuring contact resistance thereof, configured as described above, by forming the + electrode and the - electrode of the feeding electrode with a plurality of conductors, respectively, the current is supplied from each conductor to the receiving electrode, A high current can be supplied to charge a large-capacity battery.

In addition, according to the present invention, it is possible to calculate the contact resistance using the current supplied to each conductor and the voltage difference between the conductors, and prevent overheating of the electrode by referring to the calculated contact resistance.

1 is a diagram showing the configuration of a conventional top-down pantograph.
2 is a view showing a power receiving electrode installed on a typical electric vehicle roof.
3 is a perspective view showing the configuration of a pantograph suitable for supplying a large current to which the present invention is applied.
4 is a view for explaining a method for measuring contact resistance for a pantograph electrode structure suitable for supplying a large current according to an embodiment of the present invention.
5 is a plan view showing the contact state between the feeding electrode and the receiving electrode according to the pantograph electrode structure suitable for supplying a large current according to the present invention.
6 is a block diagram showing a structure of a pantograph electrode suitable for supplying a large current according to the present invention.
7 is a view for explaining a method for measuring contact resistance according to another embodiment of the present invention.

Hereinafter, the configuration of the pantograph electrode structure suitable for supplying a large current according to the present invention will be described in detail with reference to the accompanying drawings.

In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, the terms described below are terms defined in consideration of functions in the present invention, which may vary according to intentions or customs of users and operators. Therefore, the definition should be made based on the content throughout this specification.

3 is a perspective view showing the configuration of a pantograph suitable for supplying a large current to which the present invention is applied, and FIG. 4 is a side view showing the contact state between the feeding electrode and the receiving electrode according to the pantograph electrode structure suitable for supplying a large current according to the present invention, FIG. is a plan view showing the contact state between the feeding electrode and the receiving electrode according to the pantograph electrode structure suitable for supplying a large current according to the present invention.

3 to 6, a pantograph suitable for supplying a large current to which the present invention is applied is an arm 20 that is folded according to the operation of the elevating unit 10 and the elevating unit 10 as shown in FIG. 3, It may be composed of a feeding electrode 110 installed at the lower end of the arm.

As shown in FIGS. 4 and 5 , the feeding electrode 110 may include a + electrode 111 , a - electrode 113 , a ground electrode 115 , and a control pilot (CP) electrode 117 . Among the electrodes, charging power for charging the battery of the electric vehicle may be transmitted through the + electrode 111 and the - electrode 113 .

In the + electrode 111 , a plurality of conductors C are spaced apart from each other to supply a large current, so that each conductor C is in contact with the + electrode 41 on the receiving side of the receiving electrode 40 at right angles to the current. while supplying current. The conductors of the + electrode 111 may be arranged in parallel at equal intervals, but the arrangement structure is not limited thereto.

- The electrode 113 has a plurality of conductors (C) spaced apart from each other to supply a large current, so that each conductor (C) is in contact with the receiving side of the receiving electrode (40) in a direction perpendicular to the -electrode (43). while supplying current. The conductors of the - electrode 113 are preferably provided in the same number as the + electrode 111 and may be arranged in parallel with each other at equal intervals, but the arrangement number or structure is not limited thereto.

The ground electrode 115 may be formed of a single conductor and may provide a ground potential to the electric vehicle side while in contact with the power receiving side ground electrode 45 of the power receiving electrode 40 in a perpendicular direction. Here, one ground electrode 115 is provided, but the present invention is not limited thereto.

The CP electrode 117 is formed of a single conductor and is in contact with the power receiving side CP electrode 48 of the power receiving electrode 40 in a perpendicular direction. At this time, the CP electrode 117 is not limited to the number of conductors, and can transmit and receive a control signal for controlling the state of charge as a control electrode for controlling the state of charge.

In addition, the conductors C of the + and - electrodes 111 and 113 may generally supply currents of the same magnitude. For example, when three conductors are applied, if 1000A is supplied, a large current of 3000A is supplied, and when four conductors are applied, a large current of 4000A can be supplied. In addition, currents may be supplied to each of the conductors C of the + and - electrodes 111 and 113 by the same power source, but currents may be respectively supplied by separate power sources. In addition, although the current supplied to each conductor C may be the same, it is also possible to be configured to supply different currents.

Meanwhile, in the present invention, as shown in FIGS. 4 and 6 , the currents I ₁ , I ₂ , I ₃ supplied to the respective conductors C of the + and - electrodes 111 and 113 and the respective conductors C) The voltage difference (V ₁₂ , V ₂₃ , V ₃₁ ) may be used to calculate the contact resistance (r ₁ , r ₂ , r ₃ ), and may include a contact resistance calculator 120 for calculating the contact resistance. have. In addition, the present invention may further include a voltage measuring means (not shown) for measuring the voltage difference (V ₁₂ , V ₂₃ , V ₃₁ ) between the conductors C of the + and - electrodes 111 and 113 . have.

As an embodiment of the present invention, the contact resistance calculating unit 120 includes the currents I ₁ , I ₂ supplied to each of the conductors C when there are three conductors C of the + and - electrodes 111 and 113 . , I ₃ ) and the voltage difference (V ₁₂ , V ₂₃ , V ₃₁ ) between each conductor C measured by a voltage measuring means, the contact resistance (r ₁ , r ₂ , r ₃ ) of each conductor (C) ), a system of equations such as the following Equation 1 may be used.

Looking at Equation 1, it is not easy to calculate the contact resistances (r ₁ , r ₂ , r ₃ ) by combining the equations of Equation 1 because the three equations presented in Equation 1 cannot be viewed as independent equations. .

Therefore, in order to additionally obtain an expression independent of Equation 1, Equation 2 is obtained by varying the currents I ₁ , I ₂ , I ₃ supplied to each conductor C of the + and - electrodes 111 and 113 . can be obtained

Here, V _ij is the voltage difference of a pair of conductors arbitrarily selected from among the voltage differences (V ₁₂ , V ₂₃ , V ₃₁ ) between the respective conductors C, and I _i and I _j are currents flowing through each of the selected pair of conductors. , and r _i and r _j are the contact resistances of each of the selected pair of conductors.

In order for the equation of Equation 2 to be independent of Equation ₁ , the currents I _i and I _j are, if i and j are 1 and ₂ , respectively, I _i : I _j ≠ I ₁ : I ₂ and if i and j are 2 and 3, respectively, with respect to I ₂ and I ₃ in Equation 1, I _i : I _j ≠ I ₂ : I ₃ , and if i and j are 3 and 1, respectively, Equation 1 For I ₃ , I ₁ of I _i : I _j ≠ I ₃ : I ₁ needs to be controlled to satisfy the condition.

When Equation 2 satisfies the above-described condition, the contact resistance calculator 120 of the present invention may calculate the contact resistances r ₁ , r ₂ , r ₃ by combining Equations 1 and 2 together. .

In addition, although the case where there are three conductors C of the + and - electrodes 111 and 113 has been described above as an example, the number of conductors C of the + and - electrodes 111 and 113 is 2, 4, or the same. Even in the above case, the contact resistance can be calculated in a similar manner to the above-described method, respectively. For example, when there are four conductors C of the + and - electrodes 111 and 113, the currents I ₁ , I ₂ , I ₃ supplied to each of the conductors C of the + and - electrodes 111 and 113 are , I ₄ ) and the voltage difference (V ₁₂ , V ₂₃ , V ₃₄ , V ₄₁ ) between each conductor (C) to obtain simultaneous equations corresponding to Equations 1 and 2, and by combining them, the contact resistance ( r ₁ , r ₂ , r ₃ , r ₄ ) can be calculated.

If this is applied to the case where the number of conductors C of the + and - electrodes 111 and 113 is n (n is a natural number greater than or equal to 2), the following Equation 3 can be obtained.

Here, V _ij is the voltage difference of a pair of conductors arbitrarily selected from among the voltage differences (V ₁₂ , V ₂₃ , V ₃₄ , ..., V _n1 ) between the n conductors C, and I _i and I _j are Current flowing through each of the pair of conductors, and _{ri and r j are} the contact resistances of each of the selected pair of conductors.

In addition, in order for the V _ij equation of Equation 3 to be independent of the rest of the equations, the ratio of the currents I _i and I _j is, as described above, the currents I ₁ , I ₂ , I ₃ , _{. _ _}

As described above, in the pantograph electrode structure of the present invention, since the + electrode 111 and the - electrode 113 of the feeding electrode 110 are each composed of a plurality of conductors according to the current design capacity, the + electrode 111 and the - electrode A large current may be supplied to the power receiving electrode 40 of an electric vehicle or the like through 113 .

In addition, according to the method for measuring the contact resistance of the pantograph electrode according to an embodiment of the present invention, the voltage difference between the current supplied to each conductor of the + and - electrodes 111 and 113 and the respective conductors on the side of the feeding electrode 110 is used. Since the contact resistance is measured by measuring the contact resistance, it is possible to easily measure the contact resistance only by measuring the voltage/current on the power supply side without changing the design of the receiving electrode 40 side, that is, the electric vehicle side. It is possible to prevent overheating of the electrode and the occurrence of fire by controlling whether to adjust, block, or continue charging.

In addition, in the method for measuring contact resistance of a pantograph electrode according to an embodiment of the present invention, not only can the contact resistance be measured before the start of charging using Equation 3 described above, but also the contact resistance value measured before the start of charging even during charging And by using at least some of the equations of Equation 3, it is possible to monitor the change of the contact resistance in real time to control whether the charging current is adjusted, cut off, or whether charging is continued when the fluctuation amount is out of a predetermined threshold value or a threshold range.

7 is a view for explaining a method for measuring contact resistance according to another embodiment of the present invention.

Referring to FIG. 7 , the feeding electrode 110 having a pantograph electrode structure according to another embodiment of the present invention includes a + electrode 111 and a - electrode 113 each composed of a plurality of conductors, + The electrode 111 and the -electrode 113 transmit charging power provided from the charger (not shown) through the receiving side + electrode 41 and the receiving side -electrode 43 to the battery of the electric vehicle (not shown). send to Although not shown in the drawings, the feeding electrode 110 may further include a ground electrode 115 and a control pilot (CP) electrode 117 in addition to the + electrode 111 and the - electrode 113 .

In addition, in the method for measuring contact resistance according to another embodiment of the present invention, the current (I ₁ , I ₂ , I ₃ ) supplied to each conductor (C) of the + and - electrodes 111 and 113 is interrupted to intermittently to each electrode. Control so that only one current is sequentially supplied to the conductor of To this end, the charger is configured such that the current (I ₁ , I ₂ , I ₃ ) can be individually or sequentially supplied by a separate power source, or the current (I ₁ , I ₂ , I ₃ ) as shown in FIG. 7 . ) may be provided with an opening/closing switch (RY1a ~ RY3a, RY1b ~ RY3b) to individually control the supply and cut off.

For example, with respect to the + electrode 41, the on-off switch RY1a is turned on and the remaining RY2a and RY3a are opened to allow only the current I ₁ to flow, or the on-off switch RY2a is turned on and the remaining RY1a and RY3a are opened to allow only the current I ₂ to flow, or , the on/off switch RY3a is turned on and the remaining RY1a and RY2a are opened to allow only the current I ₃ to flow. At this time, at least one of the opening and closing switches RY1b to RY3b of the -electrode 43 side may be turned on to provide a current path.

In addition, as shown in FIG. 6 , the present invention provides contact resistance (r ₁ , r ₂ , r) between each conductor (C) of the + and - electrodes (111, 113) and the receiving side +, - electrodes (41, 43), as shown in FIG. ₃ ) may be configured to include a contact resistance calculator 120 that calculates. In addition, the present invention may further include a voltage measuring means (not shown) for measuring the voltage difference (V ₁₂ , V ₂₃ , V ₃₁ ) between the conductors C of the + and - electrodes 111 and 113 . have.

Referring to Figure 7, the contact resistance calculator (not shown), the current (I ₁ , I ₂ , I ₃ ) supplied from the charger to each conductor of the + electrode 41 , the contact resistance r ₁ , r ₂ , r ₃ ) can be calculated as in Equation 4 below.

Here, V ₁ , V ₂ and V ₃ are the contact resistances (r ₁ , r ₂ , r ₃ ) by the currents (I ₁ , I ₂ , I ₃ ) supplied to each of the plurality of conductors of the + electrode 41 . It is a voltage applied to each, and may be obtained from the voltage difference (V ₁₂ , V ₂₃ , V ₃₁ ) between each conductor measured by the voltage measuring means.

For example, when I ₁ flows, I ₂ and I ₃ are 0, so V ₁ is equal to V ₁₂ or -V ₃₁ , and when I ₂ flows I ₁ and I ₃ are 0, so V ₂ is V ₂₃ or - It is the same as V ₁₂ , and since I ₁ and I ₂ are 0 when I ₃ flows, V ₃ can be regarded as the same voltage value as V ₃₁ or -V ₂₃ .

In the above description, measuring the contact resistance of the + electrode 41 side has been described as an example, but the contact resistance of the - electrode 43 side can also be measured in the same way, and the It is also possible to measure the contact resistance sequentially, or to measure the contact resistance at the same time.

In addition, as shown in FIG. 7 , the case where there are three conductors C of the + and - electrodes 111 and 113 has been described as an example, but the conductors C of the + and - electrodes 111 and 113 are described as an example. The number of is not limited thereto, and even when the number of conductors C is 2, 4, or more, the contact resistance can be calculated in a similar manner to the above-described method, respectively. If this is applied to the case where the conductor C of the + and - electrodes 111 and 113 is n (n is a natural number greater than or equal to 2), the contact resistance calculator 120 of the present invention can be The contact resistance can be calculated by

As described above, according to the method for measuring the contact resistance of the pantograph electrode according to another embodiment of the present invention, the voltage difference between the current supplied to each conductor of the + and - electrodes 111 and 113 and each conductor on the side of the feeding electrode 110 is measured. Since the contact resistance is measured using By controlling the current, it is possible to prevent overheating of the electrode and the occurrence of fire.

In addition, in the method for measuring the contact resistance of the pantograph electrode according to the present invention, the contact resistance can be measured before the start of charging using Equation 5 above, and in addition, using at least some equations of Equation 3, contact in real time even during charging It is also possible to monitor the change in the resistance to control whether the charging current is adjusted, cut off or continued charging when the fluctuation amount is outside a predetermined threshold value or a threshold range.

The present invention may be variously modified and may take various forms, and in the detailed description of the invention, only specific embodiments thereof have been described. However, it is to be understood that the present invention is not limited to the particular form recited in the detailed description, but rather, it is to be understood to cover all modifications and equivalents and substitutions falling within the spirit and scope of the present invention as defined by the appended claims. should be

10: elevating unit 20: arm
30, 110: feeding electrode 31, 111: + electrode
33, 113: -electrode 35, 115: ground electrode
37, 117: CP electrode 40: receiving electrode
41: power receiving side + electrode 43: receiving side -electrode
44: power receiving side ground electrode 45: receiving side CP electrode
120: contact resistance calculation unit

Claims (8)

In the pantograph electrode structure provided with a power receiving electrode that is in contact with a power receiving electrode provided in an electric vehicle and supplies a current from a charger to the receiving electrode,
The feeding electrode is
a + electrode in which a plurality of conductors are spaced apart from each other and each conductor supplies a current to the receiving electrode;
A plurality of conductors are disposed to be spaced apart from each other, and each conductor includes an electrode for supplying current to the receiving electrode,
Before the start of charging, the current flowing in the conductor of the + electrode or the - electrode is controlled to be supplied individually or sequentially according to each conductor,
Each of the contact resistances between the plurality of conductors of the + electrode or the - electrode and the corresponding receiving electrode is calculated using the current flowing through the conductor before charging starts and the voltage difference between the conductor through which the current flows and the other conductor,
The current flowing in the conductor of the + electrode or - electrode during charging is controlled to be supplied to each conductor,
During charging, the change in contact resistance between each of the plurality of conductors of the + electrode or the - electrode and the corresponding receiving electrode is determined using at least a part of the voltage difference between the current flowing through the conductor and the conductors through which the current flows during charging. A pantograph electrode structure suitable for supplying a large current, characterized in that it is monitored in real time. According to claim 1,
A plurality of opening/closing switches disposed between the + electrode and the - electrode and the charger and controlling the current flowing through the conductor of the + electrode or the - electrode to be supplied individually or sequentially according to each conductor, characterized in that it further comprises Pantograph electrode structure suitable for large current supply. According to claim 1,
A pantograph electrode structure suitable for supplying a large current, characterized in that it further comprises a contact resistance calculator for calculating the contact resistance by using the voltage difference between the current supplied to each conductor of the + electrode and the - electrode and each conductor. 4. The method of claim 3,
The contact resistance calculation unit, when the number of conductors of the + electrode or the - electrode is n (here, n is a natural number greater than or equal to 2), the contact resistance of each conductor (r ₁ , r ₂ , r ₃ , ..., r _n ) A pantograph electrode structure suitable for supplying a large current, characterized in that it is calculated.

Here, I ₁ , I ₂ , I ₃ , … , I _n is the current flowing through each of the n conductors of the + electrode or - electrode before the start of charging, V ₁ , V ₂ , V ₃ , … , V _n is the voltage applied to each contact resistance between the corresponding conductor and the receiving electrode by the current flowing through each of the n conductors. 5. The method of claim 4,
Voltage applied to each of the contact resistances V ₁ , V ₂ , V ₃ , … , V _n are each obtained from a voltage difference between a conductor through which the current flows and another conductor, a pantograph electrode structure suitable for supplying a large current. In the method for measuring contact resistance using the pantograph electrode structure suitable for supplying a large current of claim 1,
supplying current individually or sequentially to each conductor of the + electrode or - electrode before starting charging;
measuring a voltage applied to each contact resistance between each of a plurality of conductors of the + electrode or - electrode and a corresponding receiving electrode by the current flowing through each of the conductors before charging is started;
calculating the contact resistance using a current flowing through each of the conductors and a voltage applied to each of the contact resistances;
supplying a current to each conductor of the + electrode or - electrode during charging; and
By using at least a part of the voltage difference between the current flowing through the conductor during charging and the conductors through which the current flows, the change in contact resistance between each of the plurality of conductors of the + electrode or - electrode and the corresponding receiving electrode is measured in real time during charging. A method for measuring contact resistance for a pantograph electrode structure suitable for supplying a large current, comprising the step of monitoring. 7. The method of claim 6,
The step of calculating the contact resistance is, when there are n conductors of the + electrode or the - electrode (where n is a natural number greater than or equal to 2), the contact resistance (r ₁ , r ₂ , r ₃ ) of each conductor by the following equation , ..., r _n ) A method for measuring contact resistance for a pantograph electrode structure suitable for supplying a large current, characterized in that it is calculated.

Here, I ₁ , I ₂ , I ₃ , … , I _n is the current flowing through each of the n conductors of the + electrode or - electrode before the start of charging, V ₁ , V ₂ , V ₃ , … , V _n is the voltage applied to each contact resistance between the corresponding conductor and the receiving electrode by the current flowing through each of the n conductors. 8. The method of claim 7,
Voltage applied to each of the contact resistances V ₁ , V ₂ , V ₃ , … , V _n are each obtained from a voltage difference between a conductor through which the current flows and another conductor.

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