KR101306436B1 - Solar cell apparatus and method of fabricating the same - Google Patents

Abstract

Photovoltaic device according to the embodiment, the support substrate; A rear electrode layer disposed on the support substrate; A light absorbing layer disposed on the rear electrode layer; And a front electrode layer disposed on the light absorbing layer, and the support substrate includes a recess portion.
According to one or more exemplary embodiments, a method of manufacturing a solar cell apparatus includes: forming a recess in a support substrate; 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; And forming a front electrode layer on the buffer layer.

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.

A manufacturing method of a solar cell for solar power generation is as follows. First, a substrate is provided, a back electrode layer is formed on the substrate, and patterned by a laser to form a plurality of back electrodes.

Then, a light absorption layer, a buffer layer, and a high-resistance buffer layer are sequentially formed on the back electrodes. A method of forming a light absorbing layer of copper-indium-gallium-selenide (Cu (In, Ga) Se 2; CIGS system) while simultaneously or separately evaporating copper, indium, gallium and selenium in order to form the above- A method in which a metal precursor film is formed and then formed by a selenization process is widely used. The band gap of the light absorption layer is about 1 to 1.8 eV.

Thereafter, a buffer layer containing cadmium sulfide (CdS) is formed on the light absorbing layer by a sputtering process. The energy bandgap of the buffer layer is about 2.2 to 2.4 eV. Thereafter, a high resistance buffer layer including zinc oxide (ZnO) is formed on the buffer layer by a sputtering process. The energy bandgap of the high resistance buffer layer is about 3.1 to 3.3 eV.

Thereafter, a groove pattern may be formed in the light absorbing layer, the buffer layer, and the high resistance buffer layer.

Thereafter, a transparent conductive material is stacked on the high resistance buffer layer, and the groove pattern is filled with the transparent conductive material. Accordingly, a transparent electrode layer is formed on the high resistance buffer layer, and connection wirings are formed inside the groove pattern, respectively. Examples of the material used for the transparent electrode layer and the connection wiring include aluminum doped zinc oxide and the like. The energy band gap of the transparent electrode layer is about 3.1 to 3.3 eV.

Thereafter, a groove pattern is formed in the transparent electrode layer, and a plurality of solar cells may be formed. The transparent electrodes and the high resistance buffers correspond to respective cells. The transparent electrodes and the high resistance buffers may be arranged in a stripe form or a matrix form.

The transparent electrodes and the back electrodes are misaligned with each other, and the transparent electrodes and the back electrodes are electrically connected to each other by the connection wirings. Accordingly, a plurality of solar cells can be electrically connected in series with each other.

Thus, various types of photovoltaic devices can be manufactured and used to convert sunlight into electrical energy. Such a photovoltaic power generation apparatus is disclosed in, for example, Japanese Patent Application Laid-Open No. 10-2008-0088744.

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.

Photovoltaic device according to the embodiment, the support substrate; A rear electrode layer disposed on the support substrate; A light absorbing layer disposed on the rear electrode layer; And a front electrode layer disposed on the light absorbing layer, and the support substrate includes a recess portion.

According to one or more exemplary embodiments, a method of manufacturing a solar cell apparatus includes: forming a recess in a support substrate; 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; And forming a front electrode layer on the buffer layer.

The photovoltaic device according to the embodiment includes a recess located on an upper surface of the support substrate. Through the recess, the first through holes previously formed in the rear electrode layer may be omitted, thereby reducing the process time. In addition, the efficiency of the photovoltaic device may be increased by reducing the dead zone inevitably generated by the first through holes.

In the method of manufacturing a solar cell apparatus according to the embodiment, it is possible to manufacture a solar cell apparatus having the above effect.

1 is a plan view illustrating a solar cell panel according to an embodiment.
2 is a cross-sectional view illustrating a cross section taken along a line AA ′.
3 to 5 are cross-sectional views illustrating a method of manufacturing a solar cell panel according to an 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. The criteria for top / bottom or bottom / bottom of each layer are 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 and 2, the 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 support substrate 100 includes a recess 120. The recess 120 has a recessed structure.

The recess 120 may be located on an upper surface of the support substrate 100.

The inner side surface of the recess 120 is inclined. In detail, the recess 120 may be inclined with respect to the upper surface of the support substrate 100 in an overhang structure. Specifically, the angle θ from the inner side surface of the recess portion 120 to the inner side surface of the recess portion 120 to the upper surface of the recess portion 120 may be 45 ° to 80 °. . When the angle θ from the inner side surface of the recess portion 120 to the inner side of the recess portion 120 to the upper surface of the recess portion 120 is less than 45 °, the photovoltaic device May cause structural instability. When the angle θ from the inner side surface of the recess portion 120 to the inner side of the recess portion 120 to the upper surface of the recess portion 120 exceeds 80 °, the support substrate ( There is a possibility that the back electrode layer 200 located on the upper surface of 100 is energized. That is, through the recess 120, the back electrode layer 200 is divided into a plurality of back electrodes, from the inner side of the recess 120 to the inside of the recess 120. When the angle to the top surface of the recess 120 is greater than 80 °, when the back electrode layer 200 is formed, the back electrode is also formed on the inner surface of the recess 120. There is a possibility of contact of the electrodes.

The ratio of the depth D of the recess 120 to the thickness T of the back electrode layer 200 may be 2: 1 to 4: 1. For example, when the thickness T of the back electrode layer 200 is about 470 nm, the depth D of the recess 120 may be 1 μm to 1.5 μm. This is a value considering an error range of the thickness T of the back electrode layer 200.

Through the recess 120, the first through holes previously formed in the rear electrode layer 200 may be omitted, thereby reducing the process time. In addition, the efficiency of the photovoltaic device may be increased by reducing the dead zone inevitably generated by the first through holes.

The rear electrode layer 200 is disposed on the supporting substrate 100. In addition, the back electrode layer 200 may be positioned on an upper surface of the recess 120 in the recess 120 of the support substrate 100. The rear 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 rear electrode layer 200 may include two or more layers. At this time, the respective 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 absorption layer 300 includes an I-III-VI group compound. For example, the light absorption layer 300 may be formed of a copper-indium-gallium-selenide (Cu (In, Ga) Se 2; CIGS) crystal structure, a copper- 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.

Second through holes (TH2) are formed in the light absorbing layer (300), the buffer layer (400), and the high resistance buffer layer (500). The second through holes (TH2) penetrate the light absorbing layer (300). In addition, the second through holes TH2 are open regions exposing the top surface of the back electrode layer 200.

The second through holes TH2 are positioned adjacent to the recess 120. That is, some of the second through holes TH2 are formed next to the recess 120 when viewed in a plan view. The second through grooves TH2 extend in the first direction.

The width of the second through holes TH2 may be about 80 μm to about 200 μm.

In addition, the light absorbing layer 300 defines a plurality of light absorbing portions 310, 320... By the second through holes TH2. That is, the light absorbing layer 300 is divided into the light absorbing portions 310. 320... By the second through holes TH2.

The buffer layer 400 is defined as a plurality of buffers by the second through holes TH2. That is, the buffer layer 400 is divided into the buffers by the second through holes TH2.

The high resistance buffer layer 500 is defined as a plurality of high resistance buffers by the second through holes TH2. That is, the high resistance buffer layer 500 is divided into the high resistance buffers by the second through holes TH2.

The front electrode layer 600 is disposed on the light absorption layer 300. More specifically, 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 for the front electrode layer 600 include Al-doped ZnO (AZO), indium zinc oxide (IZO), indium tin oxide (ITO), and the like. .

The thickness of the front electrode layer 600 may be about 500 nm to about 1.5 占 퐉. 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 front electrode layer 600 may be automatically patterned by the second through holes TH2. The front electrode layer 600 may be divided into a plurality of front electrodes by the second through holes TH2.

The front electrodes have a shape corresponding to the rear electrodes. That is, the front electrodes are arranged in a stripe form. Alternatively, the front electrodes may be arranged in a matrix form.

In addition, a plurality of cells C1, C2... Are defined by the second through holes TH2. That is, the photovoltaic device according to the embodiment is divided into the cells C1, C2... By the second through holes TH2. In addition, the cells C1, C2... Are connected to each other in a second direction crossing the first direction. That is, current may flow in the second direction through the cells C1, C2...

The connection parts 700 are disposed inside the second through holes TH2. 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 is formed integrally with the front electrode layer 600. That is, the material used as the connection part 700 is the same as the material used as the front electrode layer 600.

Subsequently, third through holes TH3 are formed in the light absorbing layer 300, the buffer layer 400, the high resistance buffer layer 500, and the front electrode layer 600. The third through holes TH3 pass through the light absorbing layer 300, the buffer layer 400, the high resistance buffer layer 500, and the front electrode layer 600.

The third through holes TH3 are formed at positions adjacent to the second through holes TH2. More specifically, the third through-holes TH3 are disposed beside the second through-holes TH2. That is, when viewed in plan, the third through grooves TH3 are arranged next to the second through grooves TH2. The third through grooves TH3 may have a shape extending in the first direction.

The front electrode layer 600 is divided into a plurality of front electrodes by the second through holes TH2 and the third through holes TH3. That is, the front electrodes are defined by the second through holes TH2 and the third through holes TH3.

In addition, a plurality of cells C1, C2... Are defined by the third through holes TH3. In more detail, the cells C1, C2... Are defined by the second through holes TH2 and the third through holes TH3. That is, the photovoltaic device according to the embodiment is divided into the cells C1, C2... By the second through holes TH2 and the third through holes TH3. In addition, the cells C1, C2... Are connected to each other in a second direction crossing the first direction. That is, current may flow in the second direction through the cells C1, C2...

By the third through holes TH3, the front electrodes may be surely distinguished from each other. That is, the cells can be surely distinguished from each other by the third through holes TH3. Accordingly, the third through holes TH3 may prevent a short between the front electrodes.

The solar cell panel according to the present embodiment minimizes the short between the cells C1, C2 ... and has improved electrical characteristics.

3 to 5 are cross-sectional views illustrating a method of manufacturing a solar cell panel according to an embodiment. For a description of the present manufacturing method, refer to the description of the solar cell panel described above. The description of the solar cell panel described above may be essentially combined with the description of the present manufacturing method.

Referring to FIG. 3, the recess 120 may be formed on the support substrate 100. The recess 120 may be formed by a mechanical device such as a tip, a laser device, or a heating wire.

The recess 120 may be mechanically patterned by a tip.

In this case, the recess 120 may be patterned in a direction inclined with respect to the support substrate 100. That is, the end of the tip may extend in a direction inclined with respect to the support substrate 100. By the tip, pressure may be applied in a direction inclined with respect to the support substrate 100, and the recess 120 may be patterned.

In addition, the recess 120 may be patterned by a laser. In this case, the laser may be irradiated onto the support substrate 100 in a direction inclined with respect to the upper surface of the support substrate 100.

Accordingly, the recess 120 may be formed in a direction inclined with respect to the upper surface of the support substrate 100.

In addition, the recess 120 may be formed by a laser having an energy density eccentric. That is, the energy density of the laser may have an energy density eccentric so that the energy density of the portion close to the inner side surface of the recess 120 is higher.

Although the laser having the energy density eccentric is irradiated to the support substrate 100 perpendicular to the upper surface of the support substrate 100, the recess portion including an inner surface of the overhang structure on the support substrate 100 ( 120 may be formed.

In addition, the recess 120 may be formed by a hot wire. The recess 120 may be formed by contacting the support substrate 100 in a direction in which the hot wire is inclined with respect to the upper surface of the support substrate 100. When the support substrate 100 includes a glass material, the recess 120 may be stably formed through the hot wire.

Subsequently, referring to FIG. 4, the back electrode layer 200 is formed on the support substrate 100. 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. The back electrode layer 200 may be formed on an upper surface of the support substrate 100 and an upper surface of the recess 120. The back electrode layer 200 may be divided into a plurality of back electrodes through the recess 120.

Subsequently, referring to FIG. 5, the light absorbing layer 300, the buffer layer 400, and the high resistance buffer layer 500 are 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 a metal precursor film is formed and then subjected to selenization, a metal precursor film is formed on the rear electrode 200 by a sputtering process using a copper target, an indium target, and a gallium target.

Then, the metal precursor film is formed with a light absorbing layer 300 of copper-indium-gallium-selenide (Cu (In, Ga) Se 2, CIGS system) 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.

Thereafter, cadmium sulfide is deposited by a sputtering process or a chemical bath depositon (CBD) or the like, and the buffer layer 400 is formed.

Then, zinc oxide is deposited on the buffer layer 400 by a sputtering process or the like, and the high-resistance buffer layer 500 is 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.

A portion of the light absorbing layer 300, the buffer layer 400, and the high resistance buffer layer 500 is removed to form second through holes TH2.

The front electrode layer 600 is formed on the light absorbing layer 300 and inside the second through holes TH2. That is, the front electrode layer 600 is formed by depositing a transparent conductive material on the high resistance buffer layer 500 and inside the second through holes TH2.

For example, the front electrode layer 600 is a transparent conductive material such as zinc oxide doped with aluminum is deposited on the upper surface of the high resistance buffer layer 500 and the inside of the second through holes TH2 by a sputtering process. Can be 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. Further, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified in 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 (15)

Support substrate;
A rear electrode layer disposed on the support substrate;
A light absorbing layer disposed on the rear electrode layer; And
And a front electrode layer disposed on the light absorbing layer,
The support substrate includes a recess portion,
The solar cell apparatus, wherein the rear electrode layer is disposed on an upper surface of the recess. The method of claim 1,
The recess is a solar cell apparatus located on the upper surface of the support substrate. The method of claim 1,
The recess is inclined in an overhang structure with respect to the upper surface of the support substrate. The method of claim 1,
The recess has a recessed structure. The method of claim 1,
The solar cell apparatus of which the inner side of the recess is inclined. The method of claim 5,
An angle from an inner side surface of the recess portion to an inner side of the recess portion, wherein the angle from the upper surface of the recess portion is 45 ° to 80 °. The method of claim 1,
The back electrode layer is a solar cell apparatus located on the upper surface of the recess. The method of claim 1,
The ratio of the depth of the recess portion and the thickness of the back electrode layer is 2: 1 to 4: 1 solar power device. The method of claim 1,
Depth of the recess is 1um to 1.5um of photovoltaic device. Forming a recess in the support substrate;
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; And
Forming a front electrode layer on the buffer layer;
In the forming of the back electrode layer, the back electrode layer is formed on the top of the recess manufacturing method of the solar cell apparatus. The method of claim 10,
And a laser is irradiated to the support substrate in a direction inclined with respect to the support substrate in the step of forming the recess. The method of claim 10,
The method of manufacturing a photovoltaic device in which a heating wire is driven to the support substrate in a direction inclined with respect to the support substrate in the step of forming the recess. The method of claim 10,
And a mechanical shock is applied to the support substrate in a direction inclined with respect to the support substrate in the step of forming the recess. The method of claim 10,
And a tip including an end in a direction inclined with respect to the support substrate in the step of forming the recess. The method of claim 10,
And a recess part inclined in an overhang structure with respect to an upper surface of the support substrate.

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