JP7637857B2 - Solar cell attached to cover glass with conductive coating and its mounting method - Google Patents

Description

This invention relates to a solar power module for a flexible solar cell array, solar cells in the module, and a method for mounting the solar cells.

In recent years, flexible solar cell arrays, which are mounted on non-rigid insulating sheets such as polyimide sheets, have been attracting attention as primary power sources for artificial satellites and probes, due to the demand for weight reduction and space saving, as opposed to the conventional structure in which solar cells are mounted on rigid panels.

When solar cells are used in space, they are fitted with a cover glass to control heat and reduce radiation exposure to the solar cells. This cover glass becomes charged by plasma in space. During exploration missions, if micro-sized dust particles on the surface of a planet, such as the Moon, are charged, the dust particles will adhere to the charged cover glass, blocking sunlight from reaching the solar cell and reducing the amount of power generated.

A structure using conductive cover glass has been proposed to suppress dust accumulation during exploration missions.

As a method for suppressing dust accumulation on probes and the like, a structure has been proposed in which a cover glass patterned with a conductive indium tin oxide layer is mounted on a solar cell, as shown in Non-Patent Document 1. An AC power source is connected to this cover glass, and by applying a traveling wave created by superimposing sine waves, it is possible to remove dust that has accumulated on the shield of the probe, etc.

C. I. Calle, et al. , J. Electrostat. 67, (2009) 89.

The structure proposed in Non-Patent Document 1 as mentioned above is a prototype in the research stage, and the control circuit for applying a control signal from the AC power supply to the cover glass is directly connected to the test wire. In flexible solar cell arrays that use contact storage, the test wire acts as a barrier, making it impossible to store the module, which is an issue.

The present disclosure has been made to solve the problems described above, and aims to provide a solar cell attached to a cover glass with a conductive coating that provides a path to connect to the control circuitry required to suppress dust accumulation, even in a flexible solar cell array that uses contact storage, and a method for mounting such a solar cell.

In order to solve the above problems, the solar cell attached to the conductively coated cover glass of the present disclosure is characterized by comprising an insulating sheet that blocks heat and insulates electricity, a photovoltaic power generation element that generates electricity from sunlight and is attached to the surface of the insulating sheet, a cover glass that reduces radiation exposure to the solar cell and is attached to the photovoltaic power generation element, a transparent conductive film that covers the surface of the cover glass and has a conductive coating that transmits sunlight while being conductive like a metal material, an electrode pad that is placed on the surface of the transparent conductive film and conducts electricity, a connecting metal fitting that is joined at one end to the electrode pad and conducts electricity, a hole that is provided in the insulating sheet and allows the connecting metal fitting to pass through, and a back contact bar that is placed on the surface of the insulating sheet opposite the photovoltaic power generation element and is electrically connected to the other end of the connecting metal fitting through the hole.

The solar cell with conductively coated cover glass attached according to the present disclosure enables contact storage, such as winding, in a flexible solar cell array that uses contact storage, and maintains a path to connect to the control circuitry required to suppress dust accumulation.

1 is a cross-sectional view showing a solar cell according to a first embodiment. 1 is a top view of a solar cell according to a first embodiment. 1 is a perspective view showing contact storage of a solar cell according to a first embodiment of the present invention; FIG. 1 is a perspective view showing a part of a flexible solar cell array in which solar cells according to a first embodiment are mounted.

The following describes embodiments of the present disclosure with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals. Duplicate descriptions are appropriately simplified or omitted. Note that the present disclosure is not limited to the embodiments described below.

Embodiment 1.
A solar cell according to a first embodiment of the present disclosure will be described with reference to Fig. 1 to Fig. 4. Fig. 1 is a cross-sectional view showing a solar cell according to the first embodiment. Fig. 2 is a top view according to the first embodiment. Fig. 3 is a perspective view showing a state of contact storage with the solar cell according to the first embodiment mounted thereon. Fig. 4 is a perspective view showing a part of a flexible solar cell array with the solar cell according to the first embodiment mounted thereon.

The solar cell 100 has a flexible insulating sheet 1, a photovoltaic power generation element 2, a cover glass 3, a transparent conductive film 4, an electrode pad 5, a connecting metal fitting 6, a back contact bar 7, a photovoltaic power generation element adhesive 8, a transparent adhesive 9, holes 10, and a back contact bar adhesive 11. The insulating sheet may be a polyide film having heat resistance and electrical insulation properties, but the material is not limited to these. The photovoltaic power generation element adhesive 8 and the back contact bar adhesive 11 may be a silicone-based adhesive, but the material is not limited to these.

The photovoltaic element 2 is adhered to the insulating sheet 1 with a photovoltaic element adhesive 8. The cover glass 3 is adhered to the photovoltaic element 2 with a transparent adhesive 9. The surface of the cover glass 3 is covered with a transparent conductive film 4. The transparent conductive film 4 is electrically connected to the back contact bar 7 through holes 10 provided in the insulating sheet 1 by connecting metal fittings 6 joined to electrode pads 5 provided on the surface of the transparent conductive film 4. The back contact bar 7 is adhered to the side of the insulating sheet 1 opposite to the side to which the photovoltaic element 2 is adhered, with a back contact bar adhesive 11.

In FIG. 2, 5a, 5b, and 5c are electrode pads, 6a, 6b, and 6c are connecting fittings, and 7a, 7b, and 7c are back contact bars.

As shown in FIG. 2, the solar cell 100 has a structure with a corner crop in the longitudinal direction of the solar cell. A corner crop is a cutout at the corner of the solar cell, and corresponds to areas A and B in FIG. 2. Here, the shape of the corner crop may be a triangular cutout as in area A in FIG. 2, or a circular arc cutout as in area B, and the shape is not limited to these.

2, an electrode pad 5a is provided on the transparent conductive film 4 on the cover glass 3 near a corner crop A of the solar cell 100. The electrode pad 5a is connected to a back contact bar 7a by a connecting metal fitting 6a through a hole 10a provided in the corner crop.
This connection structure makes it possible to improve the mounting efficiency when mounting solar cells 100 in parallel, compared to a case in which no corner crops are provided.

In addition, in a flexible solar cell array 110 in which multiple solar cells 100 are arranged as shown in FIG. 3, the solar cells 100 are stored in contact by wrapping a contact sheet 1 around them. Even in the flexible solar cell array 110, it is possible to provide an electrical path.

In FIG. 2, the solar cell 100 of the present disclosure has two corner crops, and three electrode pads 5 are connected to the transparent conductive film 4 on the cover glass 3 near the corner crops. Therefore, by providing three holes 10 in the two corner crops, three parallel back contact bars 7a, 7b, and 7c can be connected to the connecting fittings 6a, 6b, and 6c for one parallel solar cell 100.

2, three electrode pads 5a, 5b, and 5c are connected to the transparent conductive film 4 on the cover glass 3. As shown in Fig. 4, the electrode pads 5a, 5b, and 5c are connected to different back contact bars 7a, 7b, and 7c, respectively, and therefore it is possible to provide an electrical path for connecting a three-phase AC power source to the cover glass 3 by, for example, applying patterning to the cover glass 3.
The solar cell 100 of the present disclosure provides an electrical path for connecting a three-phase AC power source, so that a three-phase AC signal can be applied to the patterned transparent conductive film 4 to generate a traveling wave electric field, and dust adhering to the transparent conductive film 4 on the cover glass 3 can be removed.

In FIG. 4, the corner crops in area B and area D allow the connecting fittings 6c in area C to face downward, allowing many solar cells 100 to be mounted vertically, improving mounting efficiency. Although the connecting fittings 6c in FIG. 4 face downward, the connecting fittings can also face sideways, allowing many solar cells 100 to be mounted in parallel.

According to the solar cell 100 in the first embodiment described above, by connecting the electrode pad 5 provided near the corner crop to the back contact bar 7 through the hole 10 provided in the corner crop portion using the connecting fitting 6, in a flexible solar cell array 110 having multiple solar cells 100 placed on a contact sheet 1, it is possible to store the solar cells 100 in a state where the insulating sheet 1 is rolled up and the solar cells 100 are in contact with the back surface of the insulating sheet 1, and it is possible to improve the mounting efficiency when mounting the solar cells 100 in parallel and in series.

1 Insulating sheet 2 Photovoltaic element 3 Cover glass 4 Transparent conductive film 5 Electrode pad 5a Electrode pad 5b Electrode pad 5c Electrode pad 6 Connecting fitting 6a Connecting fitting 6b Connecting fitting 6c Connecting fitting 7 Back contact bar 7a Back contact bar 7b Back contact bar 7c Back contact bar 8 Photovoltaic element adhesive 9 Transparent adhesive 10 Hole 10a Hole 10b Hole 10c Hole 11 Back contact bar adhesive 100 Solar cell 110 Flexible solar cell array A Region B Region C Region D Region

Claims (3)

A flexible insulating sheet;
a photovoltaic power generation element bonded onto a front surface of the insulating sheet;
A cover glass adhered onto the photovoltaic element;
a transparent conductive film that covers the surface of the cover glass and has a conductive coating that transmits sunlight;
an electrode pad disposed on a surface of the transparent conductive film;
A connecting fitting, one end of which is joined to the electrode pad and which conducts electricity;
a hole provided in the insulating sheet through which the connecting fitting can pass;
a back contact bar that is disposed on a back surface of the insulating sheet and is electrically connected to the other end of the connecting fitting through the hole;
A solar cell attached to a cover glass with a conductive coating. A corner crop, which is a cutout, is formed in the cover glass;
The corner crop is provided with the electrode pad and the connecting metal fitting, and the insulating sheet is provided with the hole around the corner crop, the hole leading to the surface of the back contact bar.
2. The solar cell according to claim 1, wherein the cover glass is attached to the conductive coating. A solar cell attached to a cover glass with a conductive coating according to any one of claims 1 to 2, which has an insulating sheet that insulates electricity and blocks heat.