KR101210162B1 - Solar cell apparatus and method of fabricating the same - Google Patents

Abstract

The solar cell apparatus according to the embodiment includes a support substrate; A rear electrode layer disposed on the support substrate; A light absorbing layer disposed on the back electrode layer; And a front electrode layer disposed on the light absorbing layer, wherein a first through hole penetrating the back electrode layer, the light absorbing layer, and the front electrode layer is located, is adjacent to the first through groove, and the back electrode layer and the light A second through hole penetrating the absorbent layer is positioned, and the inner side surface of the second through groove is inclined in an overhang structure with respect to the upper surface of the support substrate.
A method of manufacturing a solar cell apparatus according to an embodiment includes forming a back electrode layer on a support substrate; Forming a light absorbing layer on the back electrode layer; Forming a buffer layer on the light absorbing layer; Forming a front electrode layer on the buffer layer; Forming a first through hole penetrating the back electrode layer, the light absorbing layer, the buffer layer, and the front electrode layer; And forming a second through hole adjacent to the first through hole and penetrating through the back electrode layer and the light absorbing layer, wherein an inner surface of the second through hole has an overhang structure with respect to an upper surface of the support substrate. Inclined to

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell,

Embodiments relate to a photovoltaic device and a method of manufacturing the same.

Photovoltaic devices for converting sunlight into electrical energy include solar panels, diodes and frames.

The solar cell panel has a plate shape. For example, the solar cell panel has a rectangular plate shape. The solar cell panel is disposed inside the frame. Four side surfaces of the solar cell panel are disposed inside the frame.

The solar cell panel receives sunlight and converts it into electrical energy. The solar panel includes a plurality of solar cells. In addition, the solar cell panel may further include a substrate, a film or a protective glass for protecting the solar cells.

The solar panel also includes a bus bar connected to the solar cells. The bus bars extend from upper surfaces of the outermost solar cells and are connected to the wiring.

The diode is connected in parallel with the solar cell panel. Selective current flows through the diode. That is, when the performance of the solar cell panel is degraded, current flows through the diode. Accordingly, the short circuit of the photovoltaic device itself according to the embodiment is prevented. In addition, the photovoltaic device may further include a wire connected to the diode and the solar cell panel. The wiring connects adjacent solar cell panels.

The frame accommodates the solar cell panel. The frame is made of metal. The frame is disposed on the side of the solar cell panel. The frame accommodates side surfaces of the solar cell panel. In addition, the frame may include a plurality of subframes. In this case, the subframes may be connected to each other.

Such a photovoltaic device is mounted outdoors to convert sunlight into electrical energy. At this time, the photovoltaic device may be exposed to an external physical shock, an electric shock, and a chemical shock.

The technology related to such a photovoltaic device is described in Korean Patent Publication No. 10-2009-0059529.

On the other hand, in such a photovoltaic device, a plurality of pattern lines are formed and electrically connected. However, when the plurality of pattern lines are formed, there is a problem that a process error occurs or the efficiency is reduced due to a loss of resistance.

The embodiment is to provide a photovoltaic device having a short circuit prevention and improved performance and a method of manufacturing the same.

The solar cell apparatus according to the embodiment includes a support substrate; A rear electrode layer disposed on the support substrate; A light absorbing layer disposed on the back electrode layer; And a front electrode layer disposed on the light absorbing layer, wherein a first through hole penetrating the back electrode layer, the light absorbing layer, and the front electrode layer is located, is adjacent to the first through groove, and the back electrode layer and the light A second through hole penetrating the absorbent layer is positioned, and the inner side surface of the second through groove is inclined in an overhang structure with respect to the upper surface of the support substrate.

A method of manufacturing a solar cell apparatus according to an embodiment includes forming a back electrode layer on a support substrate; Forming a light absorbing layer on the back electrode layer; Forming a buffer layer on the light absorbing layer; Forming a front electrode layer on the buffer layer; Forming a first through hole penetrating the back electrode layer, the light absorbing layer, the buffer layer, and the front electrode layer; And forming a second through hole adjacent to the first through hole and penetrating through the back electrode layer and the light absorbing layer, wherein an inner surface of the second through hole has an overhang structure with respect to an upper surface of the support substrate. Inclined to.

Through the structure of the second through hole, it is possible to prevent an electrical short between the connection portion and the back electrode layer of the first cell.

As the connection part is positioned in the first through hole and the third through hole, a contact area between the connection parts and the back electrode layer may increase. Therefore, the contact resistance can be reduced, the series resistance can be reduced, and the fill factor can be increased. Through this, the performance of the photovoltaic device can be improved.

As described above, since the first through hole, the second through hole and the third through hole are integrally formed, the rear electrode layer and the front electrode layer may be patterned without additional through grooves. Therefore, the solar cell panel according to the embodiment can be easily manufactured.

In addition, since no additional through holes are formed, the solar cell panel according to the embodiment may have a large area effective power generation area. That is, it may be an effective power generation area after the area where the second through holes are formed. Accordingly, the solar cell panel according to the embodiment may reduce dead zones and have improved photoelectric conversion efficiency.

In the solar cell manufacturing method according to the embodiment it can be produced a solar cell having the above-described effect.

1 is a plan view illustrating a solar cell panel according to a first embodiment.
2 is a cross-sectional view illustrating a cross section taken along a line AA ′.
3 is a cross-sectional view of a solar cell panel according to a second embodiment.
4 to 7 are views illustrating a process of manufacturing the solar cell panel according to the embodiment.

In the description of embodiments, each layer, region, pattern, or structure may be “on” or “under” the substrate, each layer, region, pad, or pattern. Substrate formed in ”includes all formed directly or through another layer. Criteria for the top / bottom or bottom / bottom of each layer will be described with reference to the drawings.

The thickness or the size of each layer (film), region, pattern or structure in the drawings may be modified for clarity and convenience of explanation, and thus does not entirely reflect the actual size.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a plan view illustrating a solar cell panel according to an embodiment. FIG. 2 is a cross-sectional view taken along the line A-A 'of FIG. 1.

1 to 2, a solar cell panel includes a support substrate 100, a back electrode layer 200, a light absorbing layer 300, a buffer layer 400, a high resistance buffer layer 500, a front electrode layer 600, and a plurality of substrates. Connections 700 are included.

The support substrate 100 has a plate shape, and the back electrode layer 200, the light absorbing layer 300, the buffer layer 400, the high resistance buffer layer 500, the front electrode layer 600, and the connection portion ( 700).

The support substrate 100 may be an insulator. The support substrate 100 may be a glass substrate, a plastic substrate, or a metal substrate. In more detail, the support substrate 100 may be a soda lime glass substrate. The supporting substrate 100 may be transparent. The support substrate 100 may be rigid or flexible.

The rear electrode layer 200 is disposed on the supporting substrate 100. The back electrode layer 200 is a conductive layer. Examples of the material used as the back electrode layer 200 include a metal such as molybdenum.

In addition, the back electrode layer 200 may include two or more layers. In this case, each of the layers may be formed of the same metal, or may be formed of different metals.

The light absorbing layer 300 is disposed on the back electrode layer 200. In addition, the material included in the light absorbing layer 300 is filled in the first through grooves.

The light absorbing layer 300 includes a group I-III-VI compound. For example, the light absorbing layer 300 may be formed of a copper-indium-gallium-selenide-based (Cu (In, Ga) Se 2; CIGS-based) crystal structure, copper-indium-selenide-based, or copper-gallium-selenide-based. It may have a crystal structure.

The energy band gap of the light absorption layer 300 may be about 1 eV to 1.8 eV.

Subsequently, the buffer layer 400 is disposed on the light absorbing layer 300. The buffer layer 400 is in direct contact with the light absorbing layer 300.

The high resistance buffer layer 500 is disposed on the buffer layer 400. The high resistance buffer layer 500 includes zinc oxide (i-ZnO) that is not doped with impurities. The energy band gap of the high resistance buffer layer 500 may be about 3.1 eV to 3.3 eV.

The front electrode layer 600 is disposed on the light absorbing layer 300. In more detail, the front electrode layer 600 is disposed on the high resistance buffer layer 500.

The front electrode layer 600 is disposed on the high-resistance buffer layer 500. The front electrode layer 600 is transparent. Examples of the material used as the front electrode layer 600 include aluminum doped ZnO (AZO), indium zinc oxide (IZO), indium tin oxide (ITO), and the like. Can be.

The front electrode layer 600 may have a thickness of about 500 nm to about 1.5 μm. In addition, when the front electrode layer 600 is formed of zinc oxide doped with aluminum, aluminum may be doped at a ratio of about 2.5 wt% to about 3.5 wt%. The front electrode layer 600 is a conductive layer.

The solar cell according to the embodiment includes a first through hole TH1 and a second through hole TH2.

The first through hole TH1 penetrates the back electrode layer 200, the light absorbing layer 300, and the front electrode layer 600.

The second through hole TH2 is adjacent to the first through hole TH1 and penetrates the back electrode layer 200 and the light absorbing layer 300. Here, the second through hole TH2 includes an inner side surface 301.

The inner side surface 301 is inclined with respect to the upper surface of the support substrate 100. In more detail, the inner side surface 301 may be inclined in an overhang structure with respect to the upper surface of the support substrate 100. That is, the inner side surface 301 may be inclined inwardly of the second through holes TH2. Accordingly, the angle θ from the inner side surface 301 to the inner side of the second through holes TH2 to the upper surface of the support substrate 100 may be smaller than 90 °. In more detail, the angle from the inner side surface 301 of the second through hole TH2 to the inner side of the second through hole TH2 to the top surface of the back electrode layer 200 may be 15 ° to 85 °. have.

Through the structure of the second through hole TH2, an electrical short circuit between the connection part 700 and the back electrode layer 200 of the first cell C1 may be prevented.

In this case, the first through hole TH1 and the second through hole TH2 may be integrally formed.

Subsequently, the semiconductor device further includes a third through hole TH3 adjacent to the first through hole TH1, spaced apart from the second through hole TH2, and penetrating through the light absorbing layer 300. The third through hole TH3 exposes an upper surface of the back electrode layer 200. In detail, the third through hole TH3 may expose an upper surface of the back electrode layer 200 to about 80 μm to about 100 μm.

The first through hole TH1, the second through hole TH2, and the third through hole TH3 are integrally formed.

The connection part 700 may be located in the first through hole TH1 and the third through hole TH3. Through this, the connection part 700 may be connected to the back electrode layer 200. Specifically, the connection parts 700 extend downward from the front electrode layer 600 and are connected to the back electrode layer 200. For example, the connection parts 700 extend from the front electrode of the first cell C1 and are connected to the back electrode of the second cell C2.

Thus, the connection parts 700 connect adjacent cells to each other. In more detail, the connection parts 700 connect the front electrode and the rear electrode included in the cells C1, C2, ... which are adjacent to each other.

The connection part 700 may be integrally formed with the front electrode layer 600. That is, the material used as the connection part 700 may be the same as the material used as the front electrode layer 600.

Since the connection part 700 is positioned in the first through hole TH1 and the third through hole TH3, the contact area between the connection parts 700 and the back electrode layer 200 may increase. Therefore, the contact resistance can be reduced, the series resistance can be reduced, and the fill factor can be increased. Through this, the performance of the photovoltaic device can be improved.

As described above, since the first through hole TH1, the second through hole TH2, and the third through hole TH3 are integrally formed, the rear electrode layer may be formed without additionally forming additional through holes. 200 and the front electrode layer 600 may be patterned. Therefore, the solar cell panel according to the embodiment can be easily manufactured.

In addition, since no additional through holes are formed, the solar cell panel according to the embodiment may have a large area effective power generation area. That is, it may be an effective power generation area after the area where the second through holes TH2 are formed. Accordingly, the solar cell panel according to the embodiment may reduce dead zones and have improved photoelectric conversion efficiency.

Hereinafter, a solar cell according to a second embodiment will be described with reference to FIG. 3. Detailed descriptions of parts identical or similar to those of the first embodiment will be omitted for clarity and simplicity. 3 is a cross-sectional view of a solar cell panel according to a second embodiment.

Referring to FIG. 3, the insulating part 800 may be located in the second through hole TH2. In detail, the insulating part 800 may be positioned to cover the back electrode layer 200 in the second through hole TH2. The insulating part 800 may insulate the back electrode layer 200 and the connection part 700 of the first cell C1. That is, an electrical short circuit between the first cell C1 and the second cell C2 can be prevented.

Hereinafter, a method of manufacturing a solar cell according to an embodiment will be described with reference to FIGS. 4 to 7. 4 to 7 are views illustrating a process of manufacturing the solar cell panel according to the embodiment.

Referring to FIG. 4, the back electrode layer 200, the light absorbing layer 300, the buffer layer 400, the high resistance buffer layer 500, and the front electrode layer 600 are sequentially formed on the support substrate.

Examples of the material used for the back electrode layer 200 include molybdenum and the like. The back electrode layer 200 may be formed of two or more layers under different process conditions. In addition, an additional layer such as a diffusion barrier may be interposed between the support substrate 100 and the back electrode layer 200.

Subsequently, the light absorbing layer 300 is formed on the back electrode layer 200. The light absorption layer 300 may be formed by a sputtering process or an evaporation process.

For example, a copper-indium-gallium-selenide-based (Cu (In, Ga) Se 2; CIGS-based) light-emitting layer is formed while simultaneously evaporating copper, indium, gallium, A method of forming the light absorbing layer 300 and a method of forming the metal precursor film by a selenization process are widely used.

When the metal precursor film is formed and selenization is subdivided, a metal precursor film is formed on the back electrode 200 by a sputtering process using a copper target, an indium target, and a gallium target.

Subsequently, the metal precursor film is formed of a copper-indium-gallium-selenide (Cu (In, Ga) Se 2; CIGS-based) light absorbing layer 300 by a selenization process.

Alternatively, the copper target, the indium target, the sputtering process using the gallium target, and the selenization process may be performed simultaneously.

Alternatively, the CIS-based or CIG-based optical absorption layer 300 can be formed by using only a copper target and an indium target, or by a sputtering process and a selenization process using a copper target and a gallium target.

Subsequently, the buffer layer 400 is formed on the light absorbing layer 300. Here, cadmium sulfide is deposited by a sputtering process or a chemical bath deposit (CBD) or the like, and the buffer layer 400 is formed.

Thereafter, zinc oxide may be deposited on the buffer layer 400 by a sputtering process, and the high resistance buffer layer 500 may be formed.

The buffer layer 400 and the high resistance buffer layer 500 are deposited to a low thickness. For example, the thickness of the buffer layer 400 and the high resistance buffer layer 500 is about 1 nm to about 80 nm.

Subsequently, the front electrode layer 600 is formed on the high resistance buffer layer 500. The front electrode layer 600 may be formed by depositing a transparent conductive material such as zinc oxide doped with aluminum on the high resistance buffer layer 500 by a sputtering process.

Subsequently, referring to FIG. 5, a first through hole TH1 penetrating the back electrode layer 200, the light absorbing layer 300, the buffer layer 400, and the front electrode layer 600 may be formed. When the first through hole TH1 is formed, a laser may be irradiated to the back electrode layer 200, the light absorbing layer 300, the buffer layer 400, and the front electrode layer 600.

Subsequently, referring to FIG. 6, a second through hole TH2 adjacent to the first through hole TH1 and penetrating through the back electrode layer 200 and the light absorbing layer 300 is formed. The second through holes TH2 may be patterned by a laser. In this case, the laser may be irradiated to the back electrode layer 200 and the light absorbing layer 300 in a direction inclined with respect to the support substrate 100.

Next, referring to FIG. 7, a third through hole TH3 is formed adjacent to the first through hole TH1, spaced apart from the second through hole TH2, and penetrating the light absorbing layer 300. Go through the steps. An upper surface of the rear electrode layer 200 may be exposed through the third through hole TH3. The third through hole TH3 may be formed by applying a mechanical impact to the light absorbing layer 300 and the front electrode layer 600.

Subsequently, a connection part 700 may be formed in the first through hole TH1 and the third through hole TH3. The connection part 700 may be formed using a transparent conductive material in the form of a paste.

Although not shown in the drawings, the insulating part 800 may be further formed in the second through hole TH2 before the connection part 700 is formed.

The features, structures, effects and the like described in the foregoing embodiments are included in at least one embodiment of the present invention and are not necessarily limited to one embodiment. In addition, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the present invention. It can be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiments may be modified. It is to be understood that the present invention may be embodied in many other specific forms without departing from the spirit or essential characteristics thereof.

Claims (13)

Support substrate;
A rear electrode layer disposed on the support substrate;
A light absorbing layer disposed on the back electrode layer; And
And a front electrode layer disposed on the light absorbing layer,
A first through hole penetrating the rear electrode layer, the light absorbing layer, and the front electrode layer is located;
A second through hole adjacent to the first through hole and penetrating through the back electrode layer and the light absorbing layer, and an inner side surface of the second through hole inclined in an overhang structure with respect to an upper surface of the support substrate; Photovoltaic device. The method of claim 1,
The photovoltaic device of claim 2, wherein an angle from an inner side surface of the second through hole to the inner side of the second through hole and to an upper surface of the back electrode layer is 15 ° to 85 °. The method of claim 1,
The solar cell apparatus of claim 1, wherein the first through hole and the second through hole are integrally formed. The method of claim 2,
And a third through hole adjacent to the first through hole, spaced apart from the second through hole, and penetrating through the light absorbing layer. 5. The method of claim 4,
The third through hole exposes a top surface of the back electrode layer. 5. The method of claim 4,
And a connection part connected to the back electrode layer in the first through hole and the third through hole. The method according to claim 6,
The photovoltaic device of claim 2, wherein the second through hole further comprises an insulating portion for insulating the back electrode layer and the connection portion. 5. The method of claim 4,
The first through hole, the second through groove and the third through groove is integrally formed with the solar cell apparatus. Forming a back electrode layer on the support substrate;
Forming a light absorbing layer on the back electrode layer;
Forming a buffer layer on the light absorbing layer;
Forming a front electrode layer on the buffer layer;
Forming a first through hole penetrating the back electrode layer, the light absorbing layer, the buffer layer, and the front electrode layer;
Forming a second through hole adjacent to the first through hole and penetrating through the back electrode layer and the light absorbing layer;
The inner surface of the second through groove is inclined in an overhang structure with respect to the upper surface of the support substrate. 10. The method of claim 9,
In the step of forming the first through groove, the method of manufacturing a photovoltaic device in which a laser is irradiated to the back electrode layer, the light absorbing layer, the buffer layer and the front electrode layer. 10. The method of claim 9,
In the step of forming the second through groove, a method of manufacturing a photovoltaic device in which a laser is irradiated to the back electrode layer and the light absorbing layer in a direction inclined with respect to the support substrate. 10. The method of claim 9,
And forming a third through hole adjacent to the first through hole, spaced apart from the second through hole, and penetrating through the light absorbing layer. The method of claim 12,
The forming of the third through hole may include a mechanical shock applied to the light absorbing layer and the front electrode layer to expose the top surface of the back electrode layer.

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