JP5587830B2 - Flat cable for charging electric vehicles - Google Patents

Description

  The present invention relates to an electric vehicle charging cable used for charging a battery of an electric vehicle.

  An electric vehicle that travels using electric power stored in a battery as a power source has been put into practical use. These electric vehicles charge a battery by receiving power supply from a commercial power source supplied to each household or an outdoor charging facility. For charging the battery, an electric vehicle charging cable that connects a power supply port and a power supply battery mounted on the vehicle is used. This type of charging cable uses a conductor with a relatively large cross-sectional area to safely supply a large current to the battery of an electric vehicle and complete charging in a short time, thereby increasing the outer diameter of the cable. Flexibility is lost. Therefore, a flexible electric vehicle charging cable has been proposed in terms of storage and handling.

  In JP-A-7-226112, a composite twisted wire is formed by further twisting a plurality of aggregate strands formed by twisting a plurality of strands having a strand diameter of 0.10 to 0.32 mm. Polyvinyl chloride containing an insulation coating on the outside of the wire to form a wire core, twisting the three wire cores at a twist pitch of 10 to 20 times the outer diameter of the layer, and containing a polyester plasticizer on the outside An electric vehicle charging cable is disclosed in which a sheath made of a resin-based resin composition is formed to provide flexibility, improve handling, and reduce storage space.

JP-A-7-226112

  The electric vehicle charging cable disclosed in Japanese Patent Laid-Open No. 7-226112 is improved in flexibility and easy to bend in order to reduce handling and storage space, but it reduces the cross-sectional area of the cable. In addition, the cable structure is not designed to prevent the cable from being disturbed when it is wound up on a winding body such as a reel to store the cable after charging.

If the cross-sectional area of the cable is large, when the cable is wound along the width direction of the body of the winding body such as a reel, the “winding length” is reduced in a limited space of the winding body. Problems arise. Also, as shown in FIG. 7, when the cable is wound around the winding body, the following trouble occurs.
(1) In the limited storage space, it is impossible to wind up the cable of the planned length.
(2) The cable may deviate from the winding body and damage the cable, or in the worst case, the conductor may be disconnected.
(3) When the cable is unwound from the winder during use, the cable becomes entangled and becomes difficult to unwind.
(4) The cable is extremely folded and the conductor is easily disconnected from the folded position.

  In order to prevent the above-mentioned trouble of winding disturbance, it is necessary to arrange the cable in an aligned manner. As a method for this, the cable entry angle with respect to the winding body is made substantially constant while traversing, and the cable is wound on the winding body. A method of winding along the trunk is known.

  For this purpose, there is no choice but to separate the final guide position of the cable from the winding body, resulting in a problem that the installation space for the winding body becomes large. In addition, a mechanism such as a limit switch is provided on both sides of the winding body (rotating body saddle position) so that the end of the winding body can be recognized so that it can be easily folded back at the folding position. There is also a need for the body to wind up in alignment.

  For this reason, since the winding device or instrument provided with the traverse mechanism is required, there is a problem that a space for winding the cable becomes large and costs for the winding occur.

  In addition, the charging cable supplies a large current to the battery of the electric vehicle safely and completes the charging in a short time, so that the outer diameter of the cable is increased by using a conductor having a relatively large cross-sectional area. The larger the cable outer diameter, the higher the rigidity and the less likely it is to be elastically deformed. Therefore, a large bend radius (curvature radius) is required to gently bend the charging cable. Therefore, a large space frame is required to store the cable. It became necessary to secure a large winding body.

  In addition, as a simple method for reducing the storage space for the cable, there is a method of making it easy to bend with a flexible cable as described in the background art and storing it by winding it in a ring shape without winding it around the cable winder. In this method, when the cable is unwound during charging, the cable becomes entangled and difficult to take out.

The present invention has been made in order to solve the above-described problems. The cable storage volume is reduced by reducing the cross-sectional area of the cable by reducing the cross-sectional area of the cable by making the cable structure capable of suppressing the temperature rise due to the heat generation of the conductor. It is an object of the present invention to provide an electric vehicle charging cable that makes it possible to reduce the size of the electric vehicle and makes it possible to perform the alignment winding without using a device or an instrument for winding up the alignment.

In order to achieve the above-mentioned object, the invention according to claim 1 is a charging cable for charging an electric vehicle by connecting the electric vehicle and a power supply port, for a power line conductor, a ground line conductor, and a signal control line. Insulating cores that cover each of the conductors are arranged in a plane, and the insulation cores of the feeding conductors of each of the insulation cores are arranged at both ends of the other insulation cores arranged in a plane. Arrange and arrange adjacent to each other, cover the outer periphery of the plurality of insulated cores with an outer sheath, and form them integrally in a flat shape, thereby reducing the cross-sectional area of the feeder conductor and aligning winding By doing so, the cable storage volume is reduced and winding disturbance is prevented.

According to a second aspect of the present invention, there is provided a plurality of insulated wire cores in which the conductors of the feeder wire insulation wire core and the ground wire insulation wire core of claim 1 are divided into a plurality of wires and covered with an insulator. Are arranged side by side in parallel.

The invention according to claim 3 is characterized in that a space between each of the above-described insulated wire cores is filled with an outer sheath.

According to the cable structure for charging an electric vehicle of the present invention, the cable storage volume can be made compact by reducing the cross-sectional area of the cable by reducing the cross-sectional area of the conductor. Can be miniaturized. Also, when winding the cable on the winder, it prevents the cable from being distorted, making it impossible to wind the cable of the planned length, causing the cable to be folded, It is possible to eliminate problems such as deviating and damaging the cable.

Further, the battery provided in the electric vehicle can be charged by a commercial power source provided in a general household. When charging an electric vehicle with a commercial power source, the cable is connected to the battery of the electric vehicle, and the charging cable wound around the winding body in the trunk is extended to the outside, and the household Charging is performed by connecting to a commercial power outlet. If the cable of the present invention is used, it can be stored compactly in a limited space in the trunk. In addition, the cable can be prevented from being entangled during winding and unwinding of the cable during charging.

Sectional drawing of the flat cable for charge which concerns on the 1st Embodiment of this invention Sectional drawing of the flat cable for charge which concerns on the 2nd Embodiment of this invention Sectional drawing of the flat cable for charge which concerns on the 3rd Embodiment of this invention Sectional drawing of the comparative example 1 of the conventional round cable Sectional drawing of the comparative example 2 of the conventional round cable The state figure which wound up the flat cable for charge of the present invention to a winding body State diagram of a conventional round cable for charging wound on a winder

  Embodiments of a flat cable for charging according to the present invention will be described below. The flat cable for charging an electric vehicle of the present invention has been created based on the following knowledge.

(1) Reduction of conductor cross-sectional area by flat cable structure Generally, the upper limit of the electric current conducted in a cable is limited according to the conductor cross-sectional area used for the cable. This is because when an excessively large current is conducted with respect to the conductor cross-sectional area, the conductor generates heat due to Joule heat, and the insulator covering the conductor may be melted by heat. In this way, if the conductor itself is exposed by melting the insulator due to the heat generated by the conductor, inconveniences such as a short circuit of the electric circuit and, in some cases, ignition may occur. For this reason, it is necessary that the sum of the heat generation temperature of the conductor and the ambient temperature does not exceed the maximum allowable temperature of the insulator (the maximum temperature allowable for maintaining the performance of the insulator).

The allowable current of the cable (the maximum current value that can always flow) is calculated by the following formula.
I = η0√ {(T1-T) / (rR)}
Where I: Allowable current (A)
r: Conductor effective resistance (Ω / cm) at T1 ° C. of the insulated wire core
R: Total thermal resistance of insulated wire core (° C. cm / W)
T1: Maximum allowable temperature of insulator (insulator heat-resistant temperature)
T: Ambient temperature (° C)
η0: Allowable current reduction coefficient in the case of multiple insulated wire cores The total thermal resistance R of the insulated wire cores is calculated by the following equation.
R = R1 + R2

R1 = (P1 / 2π) loge (d2 / d1) (° C./cm/W) R2 = (10P2 / πd2) (° C./cm/W)
R1: Thermal resistance of insulator (℃ ・ cm / W)
R2: Thermal resistance of the insulation core surface (℃ ・ cm / W)
d1: Outer diameter of conductor (mm)
d2: Insulator outer diameter (mm)
P1: Insulator's intrinsic thermal resistance (℃ ・ cm / W)
P2: Specific heat resistance of surface dissipation (℃ ・ cm / W)

From the above formula, the allowable current of the cable varies according to the following.

(1) Conductor effective resistance at T1 ° C of the insulation core (because the amount of heat generated varies depending on the electrical resistance)
(2) Insulation core arrangement method (because the ease of heat dissipation differs depending on the insulation core arrangement method)
(3) Kind of insulator (because the allowable temperature of insulation coating varies depending on the insulator)
(4) Ambient temperature (because the ambient temperature is high, the current required to reach the allowable insulation coating temperature decreases)
Here, when the cable having the same allowable current is manufactured with the insulator (3) and the ambient temperature of (4) being constant, by disposing a power feeding insulation core at both ends, The insulation resistance of the flat structure that can increase the allowable current reduction coefficient (η0) has a larger effective conductor resistance (r) at T1 ° C. than the arrangement of the insulation structure of the round structure. be able to. From this, the conductor effective resistance (r) is inversely proportional to the conductor cross-sectional area, so that the conductor cross-sectional area (that is, the diameter) can be made smaller than the round arrangement by arranging the insulating cores in a flat arrangement.

  From the above, when manufacturing cables having the same allowable current, the cross-sectional area of the flat structure cable of the present invention can be reduced by making the conductor cross-sectional area smaller than that of the conventional round structure cable.

  Further, by adopting a flat structure, even when the cable is wound over a plurality of layers, the cable can be wound in an aligned state without disturbing the winding state as shown in FIG. As a result, the size of the cable housing can be reduced.

  Hereinafter, embodiments of a flat cable for charging according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view of a flat cable for charging according to a first embodiment for supplying a commercial power source drawn into a house to an electric vehicle. Table 1 shows the configuration of the cable. The cable of this example is a flat cable having an allowable current of 15 A, which is used at an ambient temperature of 30 ° C. using PVC whose insulator is a maximum allowable temperature of 60 ° C. The allowable current reduction coefficient (η0) in the case of a large number of insulated wire cores arranged in a flat cable structure is the 3-3 “Creativity in Japan” of JCS 0168-1 “Calculation of allowable current of power cable of 33KV or less”. According to Table 3.1 of “Reduction rate due to strip installation”, η0 = 1.
From this, by obtaining the conductor effective resistance (r) of the power supply insulation core 1 at the allowable current 15A, the maximum allowable insulator temperature 60 ° C., and the ambient temperature 30 ° C. from the above formula, The conductor cross-sectional area is calculated to be 1.04 mm ² . In this example, a conductor having an outer diameter of 1.3 mmφ in which 82 strands of 0.127 mmφ were twisted so that the conductor cross-sectional area was 1.04 mm ² was used. In addition, the conductor of the grounding insulating core 2 was a conductor having the same cross-sectional area as that of the feeding insulating core 1 on the assumption that the same amount of current flows as that of the insulating core 1 for feeding line. The conductor cross-sectional area of the signal control insulating wire core 3 is determined by a signal to be transmitted. In this example, the outer diameter of a cross-sectional area of 0.76 mm ^{2 obtained by} twisting 60 strands having a strand diameter of 0.127 mmφ. A 1.1 mmφ conductor was used.
Then, a PVC insulating coating having a thickness of 0.8 mm and a maximum allowable temperature of 60 ° C. was formed on the outside of each conductor. Next, an insulating wire core for power feeding was arranged at both ends, and four insulating wire cores were arranged adjacent to each other, and a sheath 4 having a thickness of 1.0 mm was coated on the outer side to integrally form a planar shape. This charging flat cable had a height of 5.2 mm and a width of 14.3 mm, and the cable occupation area was 74.4 mm ² . In addition, the cable occupation area was calculated | required by the rectangle (height x width) in consideration of the actual storage volume at the time of winding up on winding bodies, such as a reel.

FIG. 2 is a cross-sectional view of a charging flat cable according to the second embodiment, and Table 2 shows the configuration of this cable. In this example, a part of Example 1 is changed, so the changed part will be described, and parts that are considered to be the same as or equivalent to Example 1 are denoted by the same reference numerals and redundant description is omitted. To do.
The conductor of the insulated wire core for the feeder line and the conductor of the insulated wire core for the ground line in Example 1 were divided into two, and the insulation coating of PVC having a thickness of 0.8 mm and a maximum allowable temperature of 60 ° C. was formed outside each of the conductors. Formed.
Then, the two insulated power supply cores are arranged at both ends, respectively, and the insulation cores are arranged adjacent to each other in the same manner as in the first embodiment. Formed integrally. The dimensions of the charging flat cable were 4.7 mm high × 20 mm wide, and the cable occupation area was 94.0 mm ² . In addition, the cable occupation area was calculated | required by the rectangle (height x width) similarly to Example 1. FIG.

FIG. 3 is a cross-sectional view of a flat cable for charging according to the third embodiment, and this cable has a configuration in which a space between each insulated wire core of Example 1 is filled with an external sheath.

Comparative example

As Comparative Example 1, FIG. 4 is a cross-sectional view of a conventional charging round cable for supplying electric power to a commercial power source drawn into a house. Table 1 shows the configuration of this cable.
The cable of this example is a round cable with an allowable current of 15 A, which is used at an ambient temperature of 30 ° C. using PVC whose insulator is a maximum allowable temperature of 60 ° C.
The allowable current reduction coefficient due to multi-core convergence of the round cable can be obtained from the equation η 0 = 0.995 × n−0.362. (N is the number of insulated wire cores)
Since the cable of this example has two insulation cores for the power supply line related to heat generation, the allowable current reduction coefficient due to multi-core convergence of this round cable is η0 = 0.77 from the above equation.
From this, by obtaining the conductor effective resistance (r) of the power supply insulation core 5 at the allowable current 15A, the maximum allowable insulator temperature 60 ° C., and the ambient temperature 30 ° C. from the above formula, The conductor cross-sectional area is 1.60 mm ² . In this example, a conductor having an outer diameter of 1.6 mmφ obtained by twisting 126 strands of 0.127 mmφ so that the conductor cross-sectional area is 1.60 mm ² was used. Further, as the conductor of the grounding insulating core 6, a conductor having the same cross-sectional area as that of the feeder insulating core 5 was used for the same reason described in the first embodiment. The conductor cross-sectional area of the signal control insulating wire core 7 is determined by the transmitted signal, but in this example, the cross-sectional area of 60 strands of the same strand diameter 0.127 mmφ as in Example 1 is twisted. A conductor with an outer diameter of 1.1 mmφ and 76 mm ² was used.
Then, a PVC insulating coating having a thickness of 0.8 mm and a maximum allowable temperature of 60 ° C. was formed on the outside of each conductor. Next, four insulated wire cores, namely, two insulated wire cores for power feeding, one insulated wire core for grounding, and one insulated wire core for signal control, are twisted, and a sheath 8 having a thickness of 1.0 mm is formed on the outside thereof. Covered.
The outer diameter of this charging round cable was 9.7 mmφ, and the cable occupation area was 94.1 mm ² . In addition, the cable occupation area was calculated | required by the rectangle (outer diameter x outer diameter) similarly to Example 1.

As Comparative Example 2, FIG. 5 is a cross-sectional view of the charging round cable of the second comparative example, and Table 2 shows the configuration of this cable.
In addition, since this example changes a part of the comparative example 1, the changed part is demonstrated and the overlapping description is abbreviate | omitted about the same part as the comparative example 1. FIG.
The conductor of the insulated wire core for the feeder line and the conductor of the insulated wire core for the ground line of Comparative Example 1 were divided into two, and an insulation coating of PVC having a maximum allowable temperature of 60 ° C. with a thickness of 0.8 mm was formed on the outside of each conductor. Formed.
Next, seven insulated cores, ie, four insulated wire cores for power supply lines, two insulated cores for grounding, and one insulated core for signal control, are twisted together, and a sheath 8 having a thickness of 1.0 mm is formed on the outside thereof. Was coated.
The outer diameter of this charging round cable was 10.3 mm, and the cable occupation area was 106.1 mm ² . In addition, the cable occupation area was calculated | required by the rectangle (outer diameter x outer diameter) similarly to Example 1.

  As can be seen by comparing the Examples and Comparative Examples in Tables 1 and 2 (Comparison between Example 1 and Comparative Example 1 and Example 2 and Comparative Example 2), the electric vehicle of the present invention is used in the cables having the same allowable current. The flat cable for use was able to reduce the cable occupation area by 10 to 20% compared to the conventional round cable for electric vehicles.

  As a result, the cable of the present invention can store many cables in a limited storage frame, so that the storage portion can be reduced in size, and the winding state is not disturbed even if the cable is wound, and The cable could be wound up in an aligned state, and when the wound-up cable was unwound, it could be prevented from being unwound from the winder.

The present invention is not limited to the above-described embodiments, and various modifications can be adopted. For example, in the embodiment, the description has been given of the case where the allowable current is 15A, the insulator is PVC having the maximum allowable temperature of 60 ° C, and the ambient temperature is 30 ° C. Similar effects can be obtained without departing from the spirit of the present invention.

1 Flat cable power supply insulation core 2 Flat cable ground insulation core 3 Flat cable signal control insulation core 4 Flat cable sheath 5 Round cable power supply insulation core 6 Round Insulated wire core 7 for cable grounding Insulated wire core 8 for signal control of round cable Sheath of round cable

Claims (3)

In a charging cable for charging an electric vehicle by connecting the electric vehicle and a power supply port, the insulating wire core formed by covering each of the feeder conductor, grounding conductor and signal control conductor with a flat surface disposed, the insulating core wires of the feeding conductor of the insulated core wires, arranged adjacently disposed on both ends of the other insulated wire heart arranged in a planar shape, an insulating core wires the outer periphery of the several plurality A flat cable for charging an electric vehicle, wherein the flat cable is integrally formed by covering an outer sheath. 2. An insulating wire core formed by dividing a conductor of an insulating wire core for a feeder line and an insulating wire core for a grounding wire into a plurality of pieces and covering an insulator is arranged on both sides in a plane. A flat cable for charging an electric vehicle as described in 1.   The flat cable for charging an electric vehicle according to any one of claims 1 to 2, wherein a space between each insulated wire core is filled with an outer sheath.