JP2013016726A - Solar cell panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a possible ground fault of a bus bar as well as reduce a discharge risk, in introducing a double insulated wire as a measure against discharge of a solar cell panel mounted on an artificial satellite on an orbit.SOLUTION: A solar cell panel having solar cells arranged on a surface of the solar cell panel comprises: a conductive bus bar connected to an edge of a solar cell sequence of the plurality of solar cells connected serially; and a conductor wire which is electrically connected to the bus bar and allows current obtained by the solar cells to flow. The conductor wire configures an electric wire having a first covering which has insulation properties and covers the conductor wire, and a second covering which has electrical conductivity and covers the first covering. The electric wire has a covering removal part at which the second covering is removed over whole outer periphery at a predetermined position on the electric wire to expose the first covering on a surface. One covering of the second coverings separated at the covering removal part is allocated to a location which is not in contact with the bus bar, and is connected to a satellite ground point.

Description

The present invention relates to a solar cell panel mounted on an artificial satellite or the like flying in outer space. In particular, the present invention relates to a solar cell panel using a double-coated electric wire as a conductor wire for taking out electric power from a solar cell as a countermeasure against electric discharge generated in an orbit of an artificial satellite.

A plurality of solar cells are mounted on the surface (sunlight incident surface) of a solar cell panel mounted on an artificial satellite or the like, and each solar cell is electrically connected to constitute a solar cell circuit. Metal parts (hereinafter referred to as bus bars) are used at the power outlet from the solar cell circuit. A conductor wire is connected to the bus bar by soldering or the like, and electric power is taken out from the solar cell panel via the conductor wire.
Since solar cell panels are used in an external exposure environment to obtain sunlight, they are exposed to a large amount of radiation. For this reason, an electric wire having an insulating coating with high radiation resistance such as ETFE (ethylene tetrafluoroethylene) is generally used as the conductor wire.

Insulating coatings such as ETFE have high radiation resistance, but even with ETFE and the like, the insulating coating is cured if radiation is continuously received. When a heat cycle is applied in the cured state, a crack is generated in a part of the insulating coating. There is a concern that electric discharge occurs starting from the conductor portion of the conductor wire exposed by the crack.
Alternatively, there is a concern that the coating itself of an insulating coating such as ETFE is charged, and the insulating coating covering the conductor wire is destroyed due to discharge due to the charging of the coating.

As a countermeasure against this discharge, it is considered to apply a double-coated electric wire in which a conductor wire is covered with a double layer and the outer periphery of an insulating coating such as ETFE is covered with a layer having weak conductivity ( For example, refer nonpatent literature 1).

The following two effects are expected when a double-coated electric wire (hereinafter referred to as a conductive double-coated electric wire) in which the outer periphery is coated with this weakly conductive layer is applied.
As a first effect, by making the conductor wire coating double, even if one of the double coatings has cracks, the conductor wires are protected if there are no cracks in the other coatings. It can be prevented from being exposed.
As a second effect, by connecting the outer sheath of the double coating with a weak electrical conductivity to the satellite grounding point, the charge accumulated on the outer coating can be moved to the satellite grounding point. Charging can be prevented and the occurrence of discharge itself can be suppressed.

Qualification Of European Triple-junction Solar Cells With Astrium PVA Technology, Proc. Of the '8th European Space Power Space Power Conference', Constance, Germany, 14-19 September 2008 (ESA SP-661, September 2008), (Fig. 4 , Fig6).

In this way, by using a conductive double-clad electric wire at the power outlet of the solar cell panel and connecting the outer sheath to the satellite grounding point, the risk of the conductor being exposed is reduced and accumulated on the sheath Generation of discharge can be suppressed by moving the electric charge.
However, when the weak conductive coating on the outside of the conductive double-covered electric wire connected to the satellite grounding point and the bus bar come into contact with each other, there arises a problem that the bus bar that is the power outlet of the solar cell panel is grounded.
That is, when a conductive double-coated wire is used at the power outlet of the solar cell panel, if the weak conductive coating on the outside of the conductive double-coated wire contacts the bus bar, the bus bar will be grounded. The potential difference between the positive electrode and the negative electrode of the solar cell disappears, and as a result, there is a problem that the electric power generated by the solar cell cannot be supplied to each device of the satellite structure.

The present invention has been made in order to solve the above-described problems, and is capable of preventing discharge due to surface charging of a power extraction electric wire of a solar cell panel and capable of reliably supplying power generated by the solar cell to a satellite-mounted device. An object is to provide a battery panel.

  The solar cell panel according to the present invention is a solar cell panel in which a solar cell is arranged on the surface, and is electrically connected to the bus bar, a conductive bus bar connected to the electrode of the solar cell, and the sun An electric wire for passing a current generated in a battery is provided, and the electric wire includes a conductor wire through which an electric current flows, an insulating first coating covering the conductor wire, and a weakly conductive second covering the first coating. The electric wire has a coating removal portion in which the second coating is removed from the entire outer periphery and the first coating is exposed on the surface at a predetermined position.

  According to the present invention, the electric power generated in the solar cell panel is prevented from being discharged due to charging of the surface of the electric wire, and the bus bar is prevented from being grounded. Can be reliably supplied to satellite-equipped equipment.

(A) It is a figure explaining the structure of the solar cell panel which concerns on Embodiment 1 of this invention. (B) It is a figure which shows the A-A 'cross section of the solar cell panel which concerns on Embodiment 1. FIG. It is the figure which expanded a part of solar cell panel which concerns on Embodiment 1 of this invention. It is sectional drawing of the coating removal part in the electroconductive double covering electric wire used for the solar cell panel which concerns on Embodiment 1 of this invention. It is the figure which expanded a part of conventional solar cell panel.

Embodiment 1.
Hereinafter, the configuration of solar cell panel 100 according to Embodiment 1 will be described with reference to the drawings.

FIG. 1A is a diagram showing a schematic configuration of the solar cell panel 100 according to the first embodiment. FIG. 1B is a cross-sectional view at the position AA ′.
The solar cell panel 100 includes a solar cell panel base 110, and a plurality of solar cells 1a, 1b, ... are installed on the surface of the solar cell panel base 110. Here, the solar battery cell is a solar battery that converts solar energy into electric power by the photovoltaic effect, and is also simply referred to as a solar battery.
The front side (solar light incident side) of the solar battery cell 1 has a front side electrode as a collecting electrode, and the back side has a back side electrode as a collecting electrode.
Between adjacent solar cells 1 (for example, solar cells 1a and 1b in FIG. 1), the front side electrode of solar cell 1 (for example, the front side electrode of solar cell 1a) and the back side of the adjacent solar cell 1 An interconnector 3 that is a connection fitting for connecting in series with an electrode (for example, the back side electrode of the solar battery cell 1b) is disposed.
Similarly, a plurality of solar cells 1 are connected in series by the interconnector 3 to form a plurality of solar cell strings.
Moreover, the protective material which permeate | transmits sunlight, such as a cover glass, is adhere | attached on the front side (sunlight incident side) of the photovoltaic cell 1 with the adhesive agent (not shown).

Bus bars 2 are disposed at both ends of the solar cell strings electrically connected in series by the interconnector 3.
The bus bar 2 is connected to a conductor wire 5 for taking out electric power by solder 50 or the like.
The conductor wire 5 is also routed to the back surface side of the solar cell panel base 110 and connected to a desired satellite device. Thus, the electric power (current) generated by each solar cell string is collected in the bus bar 2 and supplied to the satellite-equipped equipment via the conductor wire 5.

The outer periphery of the conductor wire 5 is made of an insulating coating (first coating) having high radiation resistance and a weakly conductive coating (second coating) outside the first coating and covering the first coating. It is covered with a double layer to form a conductive double-clad electric wire 7.
The solar cell panel 100 is exposed to a large amount of radiation in outer space. Therefore, an insulating coating with high radiation resistance is used for the coating of the conductive double-coated wire 7. For example, ETFE (ethylene tetrafluoroethylene) is used as the insulating coating having high radiation resistance. Further, for example, black kapton (Kapton is a registered trademark) in which carbon is kneaded into polyimide is used for the outer weakly conductive coating (second coating).

In the conductive double-coated electric wire 7 of the present embodiment, at least one portion of the second coating 4 is removed, and the weakly conductive coating 4 (second coating 4) is removed at a position where it does not contact the bus bar 2. Provide a part. Here, the part from which the second coating 4 has been removed is referred to as a coating removal unit 30.
It is desirable that the sheath removing portion 30 is located as close as possible to the connection point where the bus bar and the conductor wire are electrically connected, and is not in contact with the bus bar 2.
By providing the coating removal portion 30 in this way, the second coating 4 becomes two electrically independent conductor layers 4a and 4b.

FIG. 3 is a view showing a cross section of the coating removing unit 30 in FIG. 2 at the position BB ′.
As shown in FIG. 3, the outer circumference of the conductor wire 5 is covered with an insulating coating 6 (first coating 6) having high radiation resistance and a coating (second coating 4) having weak conductivity outside thereof. Yes. And in the coating | coated removal part 30, the 2nd coating | coated 4 is removed over the outer peripheral whole region, and the 1st coating | coated 6 inside is exposed to the surface.
In the coating removal part 30, the 2nd coating | cover 4 is electrically parted and it comprises two independent conductor layers.

Furthermore, in the conductive double-coated electric wire 7 of the present embodiment, the second coating 4 that is separated from the bus bar 2 with the coating removal portion 30 interposed therebetween, that is, the second coating 4 that is electrically separated, that is, Of the second coatings 4a and 4b electrically separated by the coating removal unit 30, the second coating 4b on the side away from the connection point where the bus bar 2 and the conductor wire are connected is a satellite grounding point. (Not shown).

Next, in the solar cell panel of the present embodiment, while preventing discharge due to surface charging of the electric power take-out electric wire (conductive double-clad electric wire) of the solar cell panel, the bus bar is grounded and power is generated by the solar cell. An operation principle for avoiding a situation where power cannot be supplied to the satellite-mounted device will be described.

First, discharge suppression in a conventional solar cell panel will be described. FIG. 4 is a diagram showing a configuration of a conventional solar cell panel. In FIG. 4, a conductor wire 5 of a double coated electric wire having a weak conductive coating (second coating) on the outside is connected to the bus bar 2 of the solar cell panel, similarly to the solar cell panel 100 of the present embodiment. And the second coating 4 is connected to a satellite ground plane (not shown). However, in the conventional solar cell panel, the coating removal part 30 of this Embodiment is not provided.
In the conventional solar cell panel, the electric charge accumulated on the second coating 4 of the conductive double-clad electric wire can move to the satellite ground plane because the second coating 4 is connected to the satellite ground plane. . For this reason, it is possible to prevent the problem that the coated surface of the previous power take-out electric wire is charged and a potential difference is caused by the surface charging to cause discharge.

  However, in the conventional solar cell, there exists a possibility that the 2nd coating | cover 4 which has electroconductivity may contact the bus-bar 2. FIG. When the second coating 4 comes into contact with the bus bar 2, the bus bar 2 is short-circuited to the satellite ground via the conductive second coating 4, and the potential of the bus bar 2 is the same as the potential of the satellite ground. As a result, the operating voltage of the solar cell circuit is reduced and no power is generated.

On the other hand, in the solar cell panel 100 of this Embodiment, the coating removal part 30 from which the 2nd coating was removed is provided in at least one location of the 2nd coating 4 which has electroconductivity. By providing the coating removal unit 30, even if the second coating 4 and the bus bar 2 are in contact with each other, the bus bar and the satellite grounding surface are not short-circuited, and the operating voltage of the solar cell is reduced due to the short circuit. It is possible to avoid the phenomenon that the power is reduced and power is not generated.

In addition, it is about the position which provides the coating removal part 30, However, When the electroconductive double covering electric wire 7 itself which the one end was fixed to the bus-bar 2 by the vibration at the time of a satellite launch, and a temporal change after that moves back and forth and right and left Even so, it is desirable that the second coating 4b (see FIG. 2) is in a position where it does not contact the bus bar 2 within the range in which it can move. That is, the second coating 4b separated by the coating removing unit 30 and the bus bar 2 are separated from each other so that there is no contact.
On the other hand, in the second coating 4a (see FIG. 2, the second coating 4a on the bus bar 2 side in the second coating 4a and 4b electrically separated by the coating removing unit 30), radiation in outer space. Since the electric charge is accumulated on the second coating 4a and the coating surface is charged as in the conventional case, the length of the second coating 4a is preferably as short as possible.
As described above, the position of the coating removal unit 30 is such that the length of the second coating 4a is as short as possible within a range in which the second coating 4b on the side grounded to the satellite grounding surface does not contact the bus bar. It is desirable to provide it at a position.

As described above, in the solar cell panel 100 of the present embodiment, a predetermined position of the conductive double insulated wire 7, that is, the second coating 4 that is separated from the bus bar 2 among the separated second coatings 4. The coating removal unit 30 is provided at a position where the coating 4b does not come into contact with the bus bar 2, and the second coating 4b is grounded to the satellite grounding point.
Thereby, while avoiding that the bus-bar 2 is grounded, generation | occurrence | production of the discharge by charging the surface of the electroconductive double insulated wire 7 can be prevented.

DESCRIPTION OF SYMBOLS 1 Solar cell, 2 Bus bar, 3 Interconnector, 4 Second coating, 5 Conductor wire, 6 First coating, 7 Conductive double coating electric wire, 30 Duplicated removal part, 50 Solder, 100 Solar cell panel, 110 Solar panel base.

Claims (3)

A solar cell panel on which a solar cell is disposed, and a conductive bus bar connected to an electrode of the solar cell;
An electric wire that is electrically connected to the bus bar and carries the current generated by the solar cell;
The electric wire includes a conductor wire through which an electric current flows, an insulating first coating that covers the conductor wire, and a conductive second coating that covers the first coating, and the electric wire is formed at a predetermined position. A solar cell panel comprising: a coating removal portion in which the second coating is removed on the entire outer periphery and the first coating is exposed on the surface. The sheath removal portion is in the vicinity of a connection point where the bus bar and the conductor wire are electrically connected, and the bus bar and the conductor of the second sheath electrically separated by the sheath removal portion. 2. The solar cell panel according to claim 1, wherein the second covering farther from the connection point to which the line is connected is connected to a grounding point of a satellite. Of the second coating electrically separated by the coating removal portion, the second coating farther from the connection point where the bus bar and the conductor wire are connected is separated from the bus bar. The solar cell panel according to claim 1, wherein the solar cell panel is characterized.

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