JP2002299663A - See-through-type thin-film solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin-film solar cell module that can be manufactured by a simple method, and has see-through structure having an arbitrary pattern. SOLUTION: An integration-type solar cell structure (12) is provided. In the integration-type solar cell structure (12), a plurality of thin-film solar cell unit cells (121) are integrated on back and front regions of at least one portion of a translucent substrate (11). The thin film solar cell unit cell has a transparent front electrode layer (121a), photoelectric conversion unit layer (121b), and a back electrode layer (121c). At least at one portion of the integration-type solar cell structure (12), the transparent front electrode layer is exposed for composing a light transmission window section (121a'), and the exposed transparent front electrode layer should secure the flow of electricity in the integration- type thin-film solar cell structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a see-through type thin-film solar cell module.

[0002]

2. Description of the Related Art In a see-through type thin film solar cell module, generally, a transparent front electrode, an amorphous silicon photoelectric conversion unit and a back metal electrode are sequentially formed on a glass substrate, and then a large number of holes are formed in the back metal electrode and the photoelectric conversion unit. And cut grooves are provided. Such a see-through type solar cell module generates electric power by external light incident from the transparent front electrode side, and at the same time transmits the external light from the through hole, so that almost the entire transparent property is ensured.

However, in order to provide a through hole in the back metal electrode and the photoelectric conversion unit, a two-stage etching process (usually, wet etching for the back metal electrode and dry etching for the photoelectric conversion unit) is required. Is complicated.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a thin film having a see-through structure which can be manufactured by a simple method and which can have a light transmitting window in an arbitrary pattern which could not be achieved conventionally. It is intended to provide a solar cell module.

[0005]

According to the present invention, at least a part of the rear surface surface region of the light-transmitting substrate is provided by the present invention.
An integrated solar cell structure in which a plurality of thin film solar cell unit cells each including a transparent front electrode layer, a photoelectric conversion unit layer, and a back electrode layer are integrated, and a transparent front electrode is formed in at least a part of the structure of the integrated solar cell. The see-through type thin-film solar cell module, wherein the exposed layer constitutes a light-transmitting window, and the exposed transparent front electrode layer secures the flow of electricity in the integrated thin-film solar cell structure. Is achieved by

In this specification, the light incident side is called a front surface, and the opposite side is called a back surface.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the drawings.

FIG. 1 is a plan view of a see-through type thin-film solar cell module according to one embodiment of the present invention.
FIG. 2 is an enlarged sectional view showing a part of a section of the see-through type thin-film solar cell module shown in FIG. 1. 1 does not show the transparent sealing resin layer and the sealing member shown in FIG. 2 for simplicity.

A see-through type thin-film solar cell module 10 of the present invention shown in FIGS. And an integrated thin-film solar cell structure 12. As an example, the substrate 11 is 910 mm
It has a rectangular flat size of × 455mm, but 910m
It may also have a square plane size of mx 910 mm. Further, the width of the peripheral region 111 may be 5 to 150 mm.

The integrated thin-film solar cell structure 12 is of a type in which solar cell unit cells (also called strings) are integrated, and has a normal structure as best shown in FIG. That is, the integrated solar cell structure 12
Is composed of a plurality of solar cell unit cells 121 integrated on the translucent substrate 11. Each unit cell 121 includes, in order from the translucent substrate 11, a transparent front electrode layer 121a, an amorphous silicon-based photoelectric conversion unit 121b, and a back electrode layer 121c.

The transparent front electrode layer 121a formed on the glass substrate 11 can be formed of a transparent conductive oxide such as ITO, SnO ₂ , or ZnO. The transparent front electrode layer 121a may have a single-layer structure or a multilayer structure, and any of them can be formed by a known vapor deposition method such as an evaporation method, a CVD method, and a sputtering method.

The amorphous silicon-based photoelectric conversion unit 121b formed on the transparent front electrode layer 121a includes:
Although not shown, p is formed on the transparent front electrode layer 121a.
It has a structure in which an amorphous silicon-based semiconductor layer, an amorphous silicon-based thin film photoelectric conversion layer, and an n-type silicon-based semiconductor layer are sequentially stacked. Each of the p-type semiconductor layer, the photoelectric conversion layer and the n-type semiconductor layer is formed by plasma CVD.
It can be formed using a method. The p-type silicon-based semiconductor layer can be formed of an amorphous silicon-based semiconductor material such as silicon, silicon hydride (Si: H), or a silicon alloy such as silicon carbide or silicon germanium, and a p-type conductive material such as boron or aluminum. The type determining impurity atoms are doped. The photoelectric conversion layer is formed of an amorphous silicon-based semiconductor material such as intrinsic semiconductor silicon (such as silicon hydride) or silicon alloy such as silicon carbide and silicon germanium. If the photoelectric conversion function is sufficiently provided, a weak p-type or weak n-type amorphous silicon-based semiconductor material containing a trace amount of impurities for determining conductivity type can also be used. This photoelectric conversion layer is usually formed to a thickness in the range of 0.1 to 10 μm. The n-type silicon-based semiconductor layer can be formed of an amorphous silicon-based semiconductor material such as silicon, silicon hydride, or a silicon alloy such as silicon carbide or silicon germanium. Doped. Further, the n-type silicon-based semiconductor layer can be formed using n-type microcrystalline silicon hydride.

The back electrode layer 121c formed on the photoelectric conversion unit 121b can be formed of a metal material such as silver, aluminum, chromium, or titanium by a vapor deposition method, a sputtering method, or the like.

The above-described transparent front electrode layer 121a, photoelectric conversion unit 121b, and back electrode layer are divided by a laser scribe or the like to form a plurality of individual unit cells 121. That is, the transparent front electrode layer 121a is
1, the photoelectric conversion unit 121b is separated by the separation groove SV2, and the back electrode layer 121c is separated by the separation groove SV3 (only the separation grooves SV1 and SV3 are shown in FIG. 1). These unit cells 121 are electrically connected in series or in parallel.

As shown in FIG. 1, the peripheral region 111 of the glass substrate 11 has a back electrode layer, a photoelectric conversion unit, a transparent front surface, The electrode layer has been removed, exposing the glass surface. Thus, the glass substrate 11
By exposing the glass surface in the peripheral region 111, the adhesive strength to the sealing resin described later is improved.

Now, in such an integrated type thin film solar cell structure, a region corresponding to a specific string (in FIG. 1, 2
In one area), only the transparent front electrode layer 121a 'is formed, and the photoelectric conversion unit 121b and the back electrode layer 121c are not formed, so that the transparent front electrode layer 121a' is exposed. The exposed transparent front electrode layer 121a 'constitutes a light transmission window.

Here, the exposed transparent front electrode layer 121 is exposed.
a ′ is the flow of electricity in the integrated thin-film solar cell structure (in the strings adjacent to each other across the exposed transparent front electrode layer 121a ′, the transparent front electrode layer 121a, the photoelectric conversion unit 121b, and the back electrode layer of one of the strings 121c to the transparent front electrode layer 121 of the other string
a, photoelectric conversion unit 121b and back electrode layer 121
In order to ensure the flow of electricity to c, it is formed continuously with the transparent front electrode 121a of one of the strings (particularly, see FIG. 2).

In order to manufacture the thin-film solar cell module 10 having such a see-through structure, a transparent front electrode layer is formed almost entirely on the light-transmitting substrate 11, and then the separation groove SV1 is formed by laser scribe or the like. At the time of formation, in a region where the light transmitting window portion 121a 'is to be formed, a necessary separation groove is not formed in the transparent front electrode layer when forming a string. Thereafter, after forming the entire surface of the photoelectric conversion unit, forming the separation groove SV2, forming the entire surface of the back electrode layer, and forming the separation groove SV3, the back electrode layer formed on the light transmitting window 121a 'and the photoelectric conversion are formed. The unit portion is removed by removing means such as etching or laser removal to remove the front transparent electrode layer 12 of the light transmitting window.
Expose 1a '. When a solvent is used for removal by etching, hydrochloric acid, nitric acid,
For removing an aqueous solution of an acid such as acetic acid or phosphoric acid or a mixture thereof, and a photoelectric conversion unit portion, carbon tetrafluoride, an aqueous solution of sodium hydroxide, or the like can be used.

Another method for manufacturing the thin-film solar cell module having the see-through structure is to form a transparent front electrode layer by the above method, provide a predetermined separation groove SV1, and then form the light-transmitting window 121a '. After the formation region is covered with a mask, the entire surface of the photoelectric conversion unit, the formation of the separation groove SV2, the formation of the entire back electrode layer, and the formation of the separation groove SV3 are performed. Thereafter, the photoelectric conversion unit and the back electrode layer portion formed on the mask are removed together with the mask to expose the window 121a '.

Needless to say, the back surface of the solar cell module described in detail above is sealed and protected by a transparent sealing member, for example, a transparent film 14 via a transparent sealing resin layer (adhesive layer) 13. (See FIG. 2).

The transparent sealing resin used in the present invention can completely seal the unit cells 121 formed on the translucent substrate 11 and firmly adhere the sealing member such as the protective film 14. It is a resin which can be cured through softening and melting by heating, and usually contains an organic peroxide-based crosslinking agent. Examples of such resins include, for example, ethylene / vinyl acetate copolymer resin (EVA),
Thermoplastic resins such as vinyl acetate / triallyl isocyanurate copolymer resin (EVAT), polyvinyl butyral (PVB), and polyisobutylene (PIB). As the sealing resin, EVA is preferable from the viewpoint of adhesiveness to the glass substrate 11 and the price, but polyvinyl butyral is preferable from the viewpoint of light resistance.

The transparent sealing film 14 protects the solar cell module when placed in an outdoor environment,
It is preferably excellent in moisture resistance and water resistance and is insulative.
Such a sealing film 14 is made of a fluororesin film such as a polyvinyl fluoride film (for example, Tedlar film (registered trademark)) or polyethylene terephthalate (P).
ET) A resin film such as a film is sealed with a sealing resin layer 13.
The organic film may have a single-layer structure or a laminated structure as long as it has a layer in contact with the organic film. As the resin film, a fluororesin film is preferable. In addition,
The back surface sealing member is not limited to the resin film 14 but may be the substrate 11
It may be a glass plate of the same size as. The back surface sealing with the transparent sealing resin and the sealing member can be performed by heating under pressure by a conventional method. Needless to say, the sealing resin fills the region between the segments 12 (the light transmitting window 112) shown in FIG. 1 by this sealing.

FIG. 3 shows a see-through type thin-film solar cell module 20 according to the present invention in which light transmitting windows 121a "constituted by exposed transparent front electrode layers are provided in parallel with each other in a direction crossing the strings. 3, the transparent back sealing resin and the transparent sealing member are not shown for the sake of simplicity, but like the solar cell module shown in FIGS. It is sealed with.

In the solar cell module 20 shown in FIG. 3, after the integrated thin-film solar cell structure is formed on the translucent substrate 11 as usual, the back electrode layer and the photoelectric conversion unit in the window 121a ″ forming region are etched. Removal,
Removal is performed by removing means such as laser removal to expose the front transparent electrode layer 121a 'of the light transmitting window. When a solvent is used for removal by etching, an aqueous solution of an acid such as hydrochloric acid, nitric acid, acetic acid, or phosphoric acid or a mixture thereof is used for removing the back electrode layer, and tetrafluoride is used for removing the photoelectric conversion unit. Carbon, an aqueous solution of sodium hydroxide, or the like can be used. Alternatively, the see-through type solar cell module 20 separates the transparent front electrode layer when the integrated thin film solar cell structure is manufactured on the translucent substrate 11 as usual,
This is a method in which the light transmission window formation region is masked, and thereafter the entire surface of the photoelectric conversion unit, the formation of the separation groove SV2, the formation of the entire back electrode layer, and the formation of the separation groove SV3 are performed as usual. Thereafter, the photoelectric conversion unit and the back electrode layer formed on the mask are removed together with the mask, and the window 1 is removed.
21a "is exposed.

In the solar cell module 20 shown in FIG. 3, since the solar cell unit cells adjacent to each other in the direction crossing the string have already secured the flow of electricity in the integrated thin-film solar cell structure due to the structure thereof, they are not shown in FIG. 1, Fig. 2
No special means for ensuring the flow of electricity as shown in (1) is required.

When the see-through type thin-film solar cell module of the present invention described above with reference to FIGS. 1 to 3 is incorporated in a building as a window or a skylight, the solar cell unit cell 121 does not transmit external light. Part 121a ',
121a "provides a so-called blind-like light transmission structure which has not been achieved conventionally because external light is transmitted.

The see-through type thin-film solar cell module of the present invention, as shown in FIGS.
1 is preferably provided on almost the entire surface, but the blind dimming transmission structure may be formed only in a partial region of the translucent substrate 11, for example, only the upper or lower half region or the central region.
Further, in order to expose the front transparent electrode layer to form the light transmission window, it is only necessary to remove the back electrode layer and the photoelectric conversion unit portion formed on the light transmission window. The see-through structure can be provided in an arbitrary pattern such as a pattern. At that time, the electrical connection between the solar cell unit cells is secured by the transparent front electrode layer, so there is no need to separately make an electrical connection,
Therefore, it is also beautiful.

[0028]

As described above, according to the present invention, there is provided a thin-film solar cell module which can be manufactured by a simple method and has a see-through structure of an arbitrary pattern which could not be achieved conventionally. You.

[Brief description of the drawings]

FIG. 1 is a plan view of a see-through thin-film solar cell module according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a part of the see-through type thin-film solar cell module of FIG. 1;

FIG. 3 is a plan view of a see-through type thin-film solar cell module according to another embodiment of the present invention.

[Explanation of symbols]

10, 20: see-through type thin-film solar cell module 11: translucent substrate 12: integrated solar cell structure 13: transparent sealing resin layer 14: transparent sealing member 121a ', 121a'': light transmitting window (exposed front surface) 121: solar cell unit cell 121a: transparent front electrode layer 121b: photoelectric conversion unit 121c: back electrode layer

Claims (1)

[Claims] An integrated solar cell in which a plurality of thin-film solar cell unit cells each including a transparent front electrode layer, a photoelectric conversion unit layer, and a back electrode layer are integrated on at least a part of a back surface region of a translucent substrate. A transparent front electrode layer is exposed in at least a part of the structure of the integrated solar cell to constitute a light transmitting window, and the exposed transparent front electrode layer is provided in the integrated thin film solar cell structure. A see-through type thin-film solar cell module, wherein the flow of electricity is secured.