KR20100032720A - Thin film solar cell and the method for fabricating thereof - Google Patents

Abstract

PURPOSE: A thin film solar cell and a manufacturing method thereof electrically disunite an in-between transparent conductive pattern locating according to the unit cell are provided so that the inner short fault is prevented in beforehand. CONSTITUTION: A plurality of front side transparent conductive patterns(130a, 130b, 130c) separating with a plurality of first separation lines(SL1) designed to the first width according to the unit cell is formed in the upper side of the substrate(110) classified into a plurality of unit cells. A first light absorption layer(141) is formed into the top of the front side transparent conductive pattern. A plurality of in-between transparent conductive patterns(170a, 170b, 170c) separating with a plurality of second break lines(SL2) designed to the second width according to the unit cell is formed into the top of the first light absorption layer. A second light absorption layer(142) is formed into the top of the in-between transparent conductive pattern. A plurality of reflective electrodes(150a, 150b, 150c) separating with a plurality of third break lines(SL3) designed to the third width according to the unit cell is formed into the top of the second light absorption layer. A plurality of back contact electrodes(160a, 160b, 160c) separating with a plurality of fourth break lines(SL4) designed to the reflective electrode upper furnace, and the fourth width according to the unit cell is formed.

Description

Thin Film Solar Cell and the method for fabrication

The present invention relates to a thin film solar cell, and more particularly, to a thin film solar cell and a method for manufacturing the same, which can improve light conversion efficiency in tandem and triple thin film solar cells.

In general, a thin film solar cell is a diode composed of a pn junction, and is classified into various types according to a material used as a light absorption layer. A solar cell using silicon as the light absorption layer is classified into a crystalline substrate type solar cell and an amorphous thin film solar cell. In addition, compound thin film solar cells using CIS (CuInSe ₂ ) or CdTe, group III-V solar cells, dye-sensitized solar cells and organic solar cells are representative solar cells.

Bulk crystalline solar cells using the above-mentioned polycrystalline silicon are mainly used, but such crystalline solar cells not only use expensive silicon raw materials in large quantities, but also increase production costs due to complicated manufacturing processes.

Recently, research is being conducted to reduce production costs by manufacturing thin-film solar cells on low-cost substrates such as glass, metal, and plastic instead of expensive silicon substrates.

Hereinafter, a thin film solar cell according to the related art will be described with reference to the accompanying drawings.

1 is a cross-sectional view schematically showing a thin film solar cell having a single junction structure according to the prior art, and more particularly, relates to an amorphous silicon thin film solar cell using amorphous silicon as a light absorption layer.

As illustrated, the thin film solar cell 5 having a single junction structure according to the related art has a substrate 10 made of transparent glass or plastic, a transparent conductive pattern 30 formed on an upper surface of the substrate 10, and the transparent A light absorption layer 40 having a pin structure including a p-type silicon layer 40a, an i-type silicon layer 40b, and an n-type silicon layer 40c sequentially stacked on the upper surface of the conductive pattern 30, and the It includes a reflective electrode 50 on the light absorption layer 40, and a rear electrode 60 formed on the reflective electrode 50.

In this case, the reflective electrode 50 is composed of one selected from the group of conductive materials including aluminum (Al) and silver (Ag) having excellent reflectance, thereby maximizing scattering characteristics of light passing through the light absorption layer 40. Function Amorphous silicon (a-Si: H) is used for the p-type, i-type, and n-type silicon layers 40a, 40b, and 40c of the light absorption layer 40.

In the above-described thin film solar cell 5, the light passing through the substrate 10 passes through the p-type silicon layer 40a and is absorbed by the i-type silicon layer 40b, and the amorphous silicon in the i-type silicon layer 40b. Electrons and holes are generated by light with energy greater than the optical band gap of (a-Si). Electrons and holes generated in the i-type silicon layer 40b are collected into the p-type silicon layer 40a and the n-type silicon layer 40c by an internal electric field, and the transparent conductive pattern 30 and the rear electrode, which are external electrodes, are collected. Bar 60 is supplied to the external circuit, through which it is possible to convert the solar energy into electrical energy.

Since the thin film solar cell 5 having the single junction structure is limited in that it can absorb only light in a short wavelength region, and thus there is a limit in improving light conversion efficiency, recently, a multi-junction capable of selectively absorbing light in a long wavelength region can be used. There is a lot of research into the structure. Tandem structure and triple structure are commercially available.

2A is a cross-sectional view schematically showing a tandem thin film solar cell according to the related art, and FIG. 2B is a cross-sectional view schematically showing a thin film solar cell having a triple structure according to the related art. In this case, the same reference numerals are used for the same names, and redundant description thereof will be omitted.

First, as shown in FIG. 2A, a thin film solar cell 5 having a tandem structure according to the related art has a substrate 10 made of transparent glass or plastic, and a transparent conductive pattern 30 formed on an upper surface of the substrate 10. And a first light absorption layer 41 having a pin structure including a p-type, i-type, and n-type silicon layer (not shown) sequentially stacked on the transparent conductive pattern 30, and the first light absorption layer ( 41, a second light absorption layer 42 having a pin structure including p-type, i-type, and n-type silicon layers (not shown) sequentially stacked on the second light absorbing layer 42, and the reflective electrode 50 on the second light absorption layer 42. ) And a rear electrode 60 formed on the reflective electrode 50.

In this case, the p-type, i-type and n-type silicon layers of the first light absorption layer 41 are amorphous silicon (a-Si: H), and the p-type, i-type, and n of the second light absorption layer 42 are formed. The type silicon layer may be any one selected from amorphous silicon-germanium (a-Si: Ge) or microcrystalline silicon (μc-Si).

In addition, as shown in FIG. 2B, the thin film solar cell 5 having a triple structure according to the related art has a first, second, and third light absorption layer (B) in a space between the transparent conductive pattern 30 and the reflective electrode 50. 43, 44, 45 are sequentially laminated.

In the triple structure, the first light absorption layer 43 has a pin structure made of amorphous silicon (a-Si), and the second light absorption layer 44 has a pin structure made of amorphous silicon-germanium (a-Si: Ge). In addition, the third light absorbing layer 45 has a pin structure made of micro-crystal silicon (μc-Si) in turn, or the first light absorbing layer 43 has a pin structure made of amorphous silicon (a-Si), The second light absorbing layer 44 has a pin structure made of microcrystalline silicon (μc-Si), and the third light absorbing layer 45 has a pin structure made of amorphous silicon-germanium (a-Si: Ge). In addition, it is also possible to apply variously by changing each structure and location.

However, in the above-described tandem structure or triple structure thin film solar cell, it is difficult to maximize the light conversion efficiency due to poor contact characteristics between each light absorption layer, that is, the p-type silicon layer and the n-type silicon layer.

Recently, in order to improve such a problem, efforts have been made to maximize light conversion efficiency through an intermediate transparent conductive pattern as a space between each light absorbing layer, but in such a structure, the intermediate transparent conductive pattern and the rear electrode are electrically contacted. There is a problem of a sharp decrease in light conversion efficiency due to an internal short defect.

The present invention has been made to solve the above-described problem, in the multi-junction thin film solar cell including a tandem structure and a triple structure to prevent the internal short failure in the structure interposing the intermediate transparent conductive pattern to the space between the light absorbing layer between It aims to maximize the light conversion efficiency.

A thin film solar cell according to the present invention for achieving the above object is a substrate divided into a plurality of unit cells; A plurality of front transparent conductive patterns separated for each unit cell by a plurality of first separation lines designed to have a first width on an upper surface of the substrate; A first light absorbing layer formed on the front transparent conductive pattern; A plurality of intermediate transparent conductive patterns separated for each unit cell by a plurality of second separation lines designed to have a second width above the first light absorption layer; A second light absorbing layer formed on the intermediate transparent conductive pattern; A plurality of reflective electrodes separated for each unit cell by a plurality of third separation lines designed to have a third width on the second light absorption layer; A first width of the reflective electrode, which is in one-to-one contact with the plurality of transparent conductive patterns by the plurality of third separation lines, and is electrically separated from the plurality of intermediate transparent conductive patterns by the second separation line, and has a fourth width. And a plurality of rear electrodes separated by the unit cells by a plurality of fourth separation lines.

At this time, the second separation line is characterized in that the thickness of 1/5 ~ 2/3 of the first light absorption layer is removed. The plurality of intermediate transparent conductive patterns are formed to a thickness of 1 ~ 30nm.

The first light absorption layer includes a p-type silicon layer, an i-type silicon layer, and an n-type silicon layer made of amorphous silicon, wherein the p-type silicon layer is 20-50 nm, the i-type silicon layer is 200-600 nm, n-type silicon The layers are each formed with a thickness of 20-50 nm.

In addition, the second light absorption layer comprises a p-type silicon layer, i-type silicon layer and n-type silicon layer made of any one selected from amorphous silicon-germanium or micro-crystal silicon, the p-type silicon layer is 20 ~ 50nm, i The type silicon layer is formed to a thickness of 400 ~ 1000nm, n-type silicon 20 ~ 50nm, respectively.

The intermediate transparent conductive pattern is formed of one selected from the group of transparent conductive oxides including indium tin oxide, tin oxide, and zinc oxide. A rear transparent conductive pattern and a third light absorbing layer are sequentially stacked in a space between the second light absorbing layer and the reflective electrode.

According to an aspect of the present invention, there is provided a method of manufacturing a thin film solar cell, wherein a plurality of first separation lines are designed to have a first width on a top surface of a substrate divided into a plurality of unit cells. Forming a front transparent conductive pattern; Forming a first light absorption layer on the front transparent conductive pattern; Forming a plurality of intermediate transparent conductive patterns separated for each unit cell by a plurality of second separation lines designed to have a second width above the first light absorption layer; Forming a second light absorbing layer on the intermediate transparent conductive pattern; Forming a plurality of reflective electrodes separated for each unit cell by a plurality of third separation lines designed to have a third width above the second light absorption layer; A first width of the reflective electrode, which is in one-to-one contact with the plurality of transparent conductive patterns by the plurality of third separation lines, and is electrically separated from the plurality of intermediate transparent conductive patterns by the second separation line, and has a fourth width. And forming a plurality of rear electrodes separated by the unit cells by a plurality of fourth separation lines.

At this time, the second separation line is characterized in that the thickness of 1/5 ~ 2/3 of the first light absorption layer is removed. The plurality of intermediate transparent conductive patterns are formed to a thickness of 1 ~ 30nm.

The first, second, third and fourth separation lines may be formed by a laser processing apparatus.

The first light absorption layer includes a p-type silicon layer, an i-type silicon layer, and an n-type silicon layer made of amorphous silicon, wherein the p-type silicon layer is 20-50 nm, the i-type silicon layer is 200-600 nm, n-type silicon The layers are each formed with a thickness of 20-50 nm.

In addition, the second light absorption layer comprises a p-type silicon layer, i-type silicon layer and n-type silicon layer made of any one selected from amorphous silicon-germanium or micro-crystal silicon, the p-type silicon layer is 20 ~ 50nm, i The type silicon layer is formed to a thickness of 400 ~ 1000nm, n-type silicon 20 ~ 50nm, respectively.

The intermediate transparent conductive pattern is formed of one selected from a group of transparent conductive oxides including indium tin oxide, tin oxide, and zinc oxide. A rear transparent conductive pattern and a third light absorbing layer are sequentially stacked in a space between the second light absorbing layer and the reflective electrode.

In the present invention, internal short defects can be prevented by electrically separating the intermediate transparent conductive patterns positioned by unit cells while maximizing light conversion efficiency through interposing an intermediate transparent conductive pattern as a space between the light absorption layers. It can be effective.

--- Example ---

In the present invention, the internal transparent defects and the rear electrode are electrically separated from each other by interposing the intermediate transparent conductive pattern as a space between the light absorbing layers for each cell, thereby preventing internal short defects, and at the same time, the optical switching efficiency. It is characterized by providing this excellent thin film solar cell.

Hereinafter, a thin film solar cell according to the present invention will be described with reference to the accompanying drawings.

Figure 3a is a cross-sectional view showing a thin film solar cell according to the present invention, to explain the tandem structure as an example.

As shown, the tandem thin film solar cell 105 according to the present invention is divided into a plurality of unit cells (C1, C2, C3) and made of a glass or metal substrate 110, and the upper portion of the substrate 110 A plurality of front transparent conductive patterns 130a separated by unit cells C1, C2, and C3 by a plurality of first separating lines SL1 designed to have a first width W1 on a surface; 130b and 130c and p-type silicon layers 141a, i-type silicon layers 141b, and n-type silicon layers 141c sequentially stacked on top surfaces of the front transparent conductive patterns 130a, 130b, and 130c. The unit cells C1 and C2 are formed by a first light absorption layer 141 having a pin structure and a plurality of second separation lines SL2 designed to have a second width W2 above the first light absorption layer 141. A plurality of intermediate transparent conductive patterns 170a, 170b, and 170c separated by C3) and sequentially stacked on top of the intermediate transparent conductive patterns 170a, 170b and 170c. A second light absorption layer 142 having a pin structure including the formed p-type silicon layer 142a, the i-type silicon layer 142b, and the n-type silicon layer 142c, and the first and second light absorption layers 141, A plurality of reflective electrodes 150a, 150b, and 150c separated by unit cells C1, C3, and C3 by a plurality of third separation lines SL3 designed to have a third width W3 to the upper portion of 142. In contact with the plurality of front transparent conductive patterns 130a, 130b and 130c in one-to-one contact with the third separation line SL3 on the reflective electrodes 150a, 150b and 150c, and by the second separation line SL2. Electrically separated from the plurality of intermediate transparent conductive patterns 170a, 170b, and 170c, and separated by unit cells C1, C2, and C3 by a plurality of fourth separation lines SL4 designed to have a fourth width W4. A plurality of rear electrodes 160a, 160b, 160c.

In this case, the reflective electrodes 150a, 150b, and 150c are made of one selected from the group of conductive materials including aluminum (Al) and silver (Ag) having excellent reflectance, and the first and second light absorption layers 141 and 142. It maximizes the scattering characteristics of light passing through it.

The front transparent conductive patterns 130a, 130b, and 130c and the intermediate transparent conductive patterns 170a, 170b, and 170c include indium tin oxide (ITO), tin oxide (SnO: F, SnO: B), and zinc oxide (ZnO). And one selected from the group of transparent conductive oxides including: Al).

In this case, the first, second, third and fourth separation lines SL1, SL2, SL3, SL4 are spaced apart from each other, and the widths W1, W2, W3, and W4 are equal to or different from each other. Can be designed.

As the p-type, i-type and n-type silicon layers 141a, 141b, and 141c of the first light absorption layer 141, amorphous silicon (a-Si: H) is used, and p of the second light absorption layer 142 is used. The type, i-type and n-type silicon layers 142a, 142b, and 142c may be any one selected from amorphous silicon-germanium (a-Si: Ge) or microcrystal silicon (μc-Si).

In general, the p-type silicon layer 141a of the first light absorption layer 141 is 20 to 50 nm, the i-type silicon layer 141b is 200 to 600 nm, and the n-type silicon layer 141c is 20 to 50 nm. The p-type silicon layer 142a of the second light absorption layer 142 is formed of 20 to 50 nm, the i-type silicon layer 142b of 400 to 1000 nm, and the n-type silicon layer 142c of 20 to 50 nm, respectively. In particular, the intermediate transparent conductive patterns 170a, 170b, and 170c interposed between the first and second light absorption layers 141 and 142 are formed to have a very thin thickness of about 1 to 30 nm.

In the above-described configuration, the first light is interposed between the first and second light absorption layers 141 and 142 through the intermediate transparent conductive patterns 170a, 170b and 170c having a very thin thickness of about 1 to 30 nm. The contact characteristics at the interface between the absorbing layer 141 and the second light absorbing layer 142 may be improved, thereby maximizing light conversion efficiency.

In addition, each unit cell (C1, C2, C3) to prevent the internal short phenomenon caused by the junction between the intermediate transparent conductive pattern (170a, 170b, 170c) and the back electrode (160a, 160b, 160c) The design of the second separation line SL2 which electrically separates the intermediate transparent conductive patterns 170a, 170b and 170c from the first light absorption layer 141, results in the intermediate transparent conductive patterns 170a, 170b and 170c and the rear electrode 160a. , 160b, 160c has the advantage of preventing the internal short failure in advance.

In particular, in the present invention, a plurality of intermediate transparent conductive patterns 170a, 170b, and 170c which are positioned for each unit cell C1, C2, and C3 are electrically separated by the design of the second separation line SL2, and the second separation line SL2 is performed. The plurality of rear electrodes 160a, 160b, and 160c respectively contacting the plurality of front transparent conductive patterns 130a, 130b, and 130c are disposed through the third separation line SL3 positioned on one side of the separation line SL2. It is characterized in that it is designed to be electrically separated from the intermediate transparent conductive patterns (170a, 170b, 170c).

In particular, in the case of the second separation line SL2, it is preferable to remove 1/5 to 1/2 the thickness of the first light absorption layer 141.

In this case, the plurality of intermediate transparent conductive patterns 170a, 170b, and 170c and the plurality of rear electrodes 160a, 160b, and 160c may be electrically separated from each other by forming the plurality of rear electrodes 160a, 160b, and 160c. This is because when a short defect occurs in which the conductive patterns 170a, 170b, and 170c are electrically contacted, the first and second light absorbing layers 141 and 142 may act as a factor of rapidly lowering the light conversion efficiency. In this case, the thin film solar cell is connected in series by electrical contact between the plurality of front transparent conductive patterns 130a, 130b and 130c and the rear electrodes 160a, 160b and 160c which are positioned for each unit cell C1, C2 and C3. It becomes possible.

Figure 3b is a plan view showing a thin film solar cell according to the present invention.

As illustrated, the thin film solar cell 105 according to the present invention cuts the plurality of cells 130 into a plurality of fourth separation lines SL4 for the purpose of improving light transmission.

In this case, in the plurality of cells 130 connected in series by rectangular processing in the vertical direction, the first and second light absorbing layers, the front transparent conductive pattern, and the like are exposed to the outside. The processing width W4 of the plurality of fourth separation lines SL4 is in the range of 50 to 80 μm, and the width W5 of the plurality of cells 130 connected in series is preferably designed in the range of 6 to 10 mm. .

The plurality of solar cells having the above-described configuration may connect the plurality of cells 130 in parallel through first and second wires (not shown) to the outermost ends.

Hereinafter, the thin film solar cell according to the present invention will be described in more detail.

4A to 4H are cross-sectional views sequentially illustrating a manufacturing process of a thin film solar cell according to the present invention in a process sequence.

As shown in FIG. 4A, indium-tin-oxide (ITO) and tin oxide (SnO: F, SnO) are divided into a plurality of unit cells (C1, C2, C3) and formed on a substrate 110 made of glass or metal. : B), the front transparent conductive layer 130 is formed of one selected from the group of transparent conductive oxides including zinc oxide (ZnO: Al). In this case, the front transparent conductive layer 130 is preferably formed to a thickness of 5000 kPa or more.

The front transparent conductive layer 130 may be any one selected from a sputtering method and a chemical vapor deposition method. In addition, a spray method of spraying a sol-gel solution containing a transparent conductive oxide material by spraying the coating or printing directly on the substrate 110 may be used.

As shown in FIG. 4B, a first laser processing apparatus (not shown) is positioned above the substrate 110 on which the front transparent conductive layer (130 of FIG. 4A) is formed, and the first laser processing apparatus is positioned. When the front transparent conductive layer is patterned by using the first laser cutting process, the same spacing is maintained for each unit cell C1, C2, C3 by a plurality of first separation lines SL1 designed to have a first width W1. A plurality of front transparent conductive patterns 130a, 130b, and 130c spaced apart from each other are formed.

In this case, the substrate 110 positioned at a portion corresponding to the first separation line SL1 located in the space between the front transparent conductive patterns 130a, 130b, and 130c is exposed to the outside by the first laser cutting process. do.

As shown in FIG. 4C, the p-type silicon layer 141a, the i-type silicon layer 141b, and the n-type silicon layer are formed on the substrate 110 on which the plurality of front transparent conductive patterns 130a, 130b, and 130c are formed. The first light absorption layer 141 having a pin structure is formed by sequentially stacking 141c.

At this time, amorphous silicon (a-Si: H) is used for the p-type, i-type, and n-type silicon layers 141a, 141b, and 141c of the first light absorption layer 141. The p-type silicon layer 141a of the first light absorption layer 141 is formed to have a thickness of 20 to 50 nm, the i-type silicon layer 141b to 200 to 600 nm, and the n-type silicon layer 141c to have a thickness of 20 to 50 nm, respectively. It is preferable.

Next, a transparent conductive layer including indium-tin oxide (ITO), tin oxide (SnO: F, SnO: B), and zinc oxide (ZnO: Al) on the pin-shaped first light absorption layer 141. Selected one of the oxide group is deposited to a thickness of 1 ~ 30nm to form an intermediate transparent conductive layer 170. The intermediate transparent conductive layer 170 may be formed in the same manner as the front transparent conductive layer (130 of FIG. 4A).

As shown in FIG. 4D, the second laser processing apparatus (not shown) is positioned above the substrate 110 on which the intermediate transparent conductive layer (170 of FIG. 4C) is formed, and the second laser processing apparatus is positioned. When the thickness of the intermediate transparent conductive layer and the first light absorption layer 141 is patterned by the second laser cutting process, the second separation designed to have a second width W2 toward one side spaced apart from the first separation line SL1. A plurality of intermediate transparent conductive patterns 170a, 170b, and 170c are spaced apart from each other by the lines SL2 at equal intervals for each of the unit cells C1, C2, and C3.

In particular, in the case of the second separation line SL2, it is preferable to remove 1/5 to 1/2 the thickness of the first light absorption layer 141. In the above-described configuration, the intermediate transparent conductive patterns 170a, 170b and 170c are formed to have a very thin thickness on the first light absorption layer 141, and the intermediate transparent conductive patterns 170a, 170b and 170c and the first light are formed. A part thickness of the absorber layer 141 is patterned for each unit cell C1, C2, C3, which will be described later.

As shown in FIG. 4E, the p-type silicon layer 142a, the i-type silicon layer 142b, and the n-type are formed on the intermediate transparent conductive patterns 170a, 170b, and 170c having the second separation line SL2. The silicon layer 142c is sequentially stacked to form a second light absorption layer 142 having a pin structure.

The p-type, i-type, and n-type silicon layers 142a, 142b, and 142c of the second light absorption layer 142 may be formed of any one of amorphous silicon-germanium (a-Si: Ge) and microcrystalline silicon (μc-Si). One can be used. At this time, the p-type silicon layer 142a of the second light absorption layer 142 is 20 to 50 nm, the i-type silicon layer 142b is 400 to 1000 nm, and the n-type silicon layer 142c is 20 to 50 nm in thickness. Each is formed.

Next, the reflective layer 150 is formed of one selected from the group of conductive materials including aluminum (Al) and silver (Ag) having excellent reflectance on the substrate 110 on which the second light absorption layer 142 is formed. The reflective layer 150 functions to maximize the scattering characteristics of light passing through the first and second light absorption layers 141 and 142.

As shown in FIG. 4F, a third laser processing apparatus (not shown) is positioned above the substrate 110 on which the second light absorption layer 142 and the reflective layer (150 of FIG. 4E) are formed. When the reflective layer, the second light absorbing layer 142, the intermediate transparent conductive patterns 170a, 170b, and 170c and the first light absorbing layer 141 are collectively patterned by a third laser cutting process using a 3 laser processing apparatus, Spaced at equal intervals for each of the unit cells C1, C2, and C3 by a third separation line SL3 designed to have a third width W3 to one side spaced apart from the first and second separation lines SL1 and SL2. A plurality of reflective electrodes 150a, 150b, 150c are formed, respectively.

In this case, a plurality of front transparent conductive patterns 130a, 130b, and 130c positioned at portions corresponding to the third separation lines SL3 are exposed to the outside by the third laser cutting process.

As shown in FIG. 4G, nickel (Ni), gold (Au), silver (Ag), and chromium (Cr) are disposed on the upper portion spaced apart from the substrate 110 on which the plurality of reflective electrodes 150a, 150b, and 150c are formed. The back metal layer 160 is formed of a single layer made of any one selected from titanium (Ti) and palladium (Pd), or any one selected from a double layer or a triple layer, which are sequentially stacked.

As shown in FIG. 4H, a fourth laser processing apparatus (not shown) is positioned above the substrate 110 on which the rear metal layer 160 (in FIG. 4G) is formed, and the fourth laser processing apparatus is used. 4 Patterning the rear metal layer, the reflective electrodes 150a, 150b and 150c, the second light absorbing layer 142, the intermediate transparent conductive patterns 170a, 170b and 170c and the first light absorbing layer 141 collectively by a laser cutting process. In this case, the unit cells C1, C2, and C3 are formed by the fourth separation line SL4 designed to have a fourth width W4 to one side spaced apart from the first, second, and third separation lines SL1, SL2, and SL3. A plurality of rear electrodes 160a, 160b, and 160c are spaced apart from each other while maintaining the same spacing.

That is, in the present invention, the first, second, third, and fourth separation lines SL1, SL2, SL3, and SL4 are designed to be spaced apart from each other.

At this time, without designing the second separation line SL2 patterned for each of the unit cells C1, C2, and C3, an intermediate transparent conductive layer (170 of FIG. 4C) is formed on the entire upper surface of the first light absorption layer 141. In addition, an internal short phenomenon caused by the junction of the intermediate transparent conductive layer and the rear electrodes 160a, 160b, and 160c may cause a line defect in which a current is not applied from one characteristic cell to the next cell.

However, as in the present invention, the interior caused by the electrical bonding between the intermediate transparent conductive patterns 170a, 170b, 170c and the rear electrodes 160a, 160b, 160c positioned for each unit cell C1, C2, C3. This problem can be solved by designing a second separation line SL2 that electrically separates the intermediate transparent conductive patterns 170a, 170b, and 170c of each unit cell C1, C2, and C3 so that a short phenomenon does not occur. In addition, there is a structural advantage that can implement a high-efficiency thin film solar cell.

In this case, a plurality of front transparent conductive patterns 130a, 130b, and 130c positioned at a portion corresponding to the fourth separation line SL4 designed to the fourth width W4 by the fourth laser cutting process are exposed to the outside. do.

Accordingly, in the present invention, a plurality of intermediate transparent conductive patterns 170a, 170b, and 170c which are positioned for each unit cell C1, C2, and C3 are electrically separated by the design of the second separation line SL2, and the second separation line SL2 is used. The plurality of rear electrodes 160a, 160b, and 160c respectively contacting the plurality of front transparent conductive patterns 130a, 130b, and 130c are disposed through the third separation line SL3 positioned on one side of the separation line SL2. By designing to be electrically separated from the intermediate transparent conductive patterns (170a, 170b, 170c) there is an advantage that can prevent the internal short failure in advance.

As mentioned above, the thin film solar cell which concerns on this invention can be manufactured.

Until now, the present invention has been described consistently with respect to the tandem structure, but this is only one example. In the triple structure, the tandem structure is a tandem other than a structure in which a rear transparent conductive pattern and a third light absorbing layer are further formed as a space between the second light absorbing layer and the reflective electrode. Since there is no great difference from the structure, description thereof will be omitted.

Therefore, it will be apparent that the present invention is not limited to the above embodiments, and various modifications and changes can be made without departing from the spirit and spirit of the present invention.

1 is a cross-sectional view schematically showing a thin film solar cell of a single junction structure according to the prior art.

Figure 2a is a schematic cross-sectional view showing a tandem thin film solar cell according to the prior art.

Figure 2b is a cross-sectional view schematically showing a triple structure thin film solar cell according to the prior art.

Figure 3a is a cross-sectional view showing a thin film solar cell according to the present invention.

Figure 3b is a plan view showing a thin film solar cell according to the present invention.

4A to 4H are cross-sectional views illustrating a manufacturing process of a thin film solar cell according to the present invention in a process sequence.

* Explanation of symbols for the main parts of the drawings *

110: substrate C1, C2, C3: unit cell

130a, 130b, 130c: front transparent conductive pattern

141, 142: first and second light absorption layers 150a, 150b, 150c: reflective electrode

160a, 160b, 160c: rear electrode

170a, 170b, 170c: Medium transparent conductive pattern

W1, W2, W3, W4: first, second, third, fourth width

SL1, SL2, SL3, SL4: first, second, third and fourth separation lines

Claims (15)

A substrate divided into a plurality of unit cells; A plurality of front transparent conductive patterns separated for each unit cell by a plurality of first separation lines designed to have a first width on an upper surface of the substrate; A first light absorbing layer formed on the front transparent conductive pattern; A plurality of intermediate transparent conductive patterns separated for each unit cell by a plurality of second separation lines designed to have a second width above the first light absorption layer; A second light absorbing layer formed on the intermediate transparent conductive pattern; A plurality of reflective electrodes separated for each unit cell by a plurality of third separation lines designed to have a third width on the second light absorption layer; A first width of the reflective electrode, which is in one-to-one contact with the plurality of transparent conductive patterns by the plurality of third separation lines, and is electrically separated from the plurality of intermediate transparent conductive patterns by the second separation line, and has a fourth width. A plurality of rear electrodes separated by the unit cells by a plurality of fourth separation lines designed as Thin film solar cell comprising a. The method of claim 1, The second separation line is a thin film solar cell, characterized in that to remove 1/5 ~ 2/3 thickness of the first light absorption layer. The method of claim 1, The plurality of intermediate transparent conductive pattern is a thin film solar cell, characterized in that formed in a thickness of 1 ~ 30nm. The method of claim 1, The first light absorption layer includes a p-type silicon layer, an i-type silicon layer, and an n-type silicon layer made of amorphous silicon, wherein the p-type silicon layer is 20-50 nm, the i-type silicon layer is 200-600 nm, n-type silicon The layer is a thin film solar cell, characterized in that each formed in a thickness of 20 ~ 50nm. The method of claim 1, The second light absorption layer includes a p-type silicon layer, an i-type silicon layer, and an n-type silicon layer formed of any one selected from amorphous silicon-germanium or micro crystal silicon, and the p-type silicon layer is 20 to 50 nm and i-type silicon. The layer is 400 ~ 1000nm, n-type silicon thin film solar cell, characterized in that formed in each of the thickness of 20 ~ 50nm. The method of claim 1, The intermediate transparent conductive pattern is a thin film solar cell, characterized in that formed of one selected from the group of transparent conductive oxides including indium tin oxide, tin oxide and zinc oxide. The method of claim 1, A thin film solar cell comprising a rear transparent conductive pattern and a third light absorbing layer sequentially stacked in a space between the second light absorbing layer and the reflective electrode. Forming a plurality of front transparent conductive patterns separated for each unit cell by a plurality of first separation lines designed to have a first width on an upper surface of a substrate divided into a plurality of unit cells; Forming a first light absorption layer on the front transparent conductive pattern; Forming a plurality of intermediate transparent conductive patterns separated for each unit cell by a plurality of second separation lines designed to have a second width above the first light absorption layer; Forming a second light absorption layer on the intermediate transparent conductive pattern; Forming a plurality of reflective electrodes separated for each unit cell by a plurality of third separation lines designed to have a third width above the second light absorption layer; A first width of the reflective electrode, which is in one-to-one contact with the plurality of transparent conductive patterns by the plurality of third separation lines, and is electrically separated from the plurality of intermediate transparent conductive patterns by the second separation line, and has a fourth width. Forming a plurality of rear electrodes separated by the unit cells by a plurality of fourth separation lines designed to be Method of manufacturing a thin film solar cell comprising a. The method of claim 8, The second separation line is a method for manufacturing a thin film solar cell, characterized in that to remove the thickness of 1/5 ~ 2/3 of the first light absorption layer. The method of claim 8, The plurality of intermediate transparent conductive pattern is a thin film solar cell manufacturing method, characterized in that formed in a thickness of 1 ~ 30nm. The method of claim 8, The first, second, third, and fourth separation line is a thin film solar cell, characterized in that formed by a laser processing apparatus. The method of claim 8, The first light absorption layer includes a p-type silicon layer, an i-type silicon layer, and an n-type silicon layer made of amorphous silicon, wherein the p-type silicon layer is 20-50 nm, the i-type silicon layer is 200-600 nm, n-type silicon The layer is a method of manufacturing a thin film solar cell, characterized in that each formed in a thickness of 20 ~ 50nm. The method of claim 8, The second light absorption layer includes a p-type silicon layer, an i-type silicon layer, and an n-type silicon layer formed of any one selected from amorphous silicon-germanium or micro crystal silicon, and the p-type silicon layer is 20 to 50 nm and i-type silicon. The layer is 400 ~ 1000nm, n-type silicon manufacturing method of a thin film solar cell, characterized in that each formed in a thickness of 20 ~ 50nm. The method of claim 8, The intermediate transparent conductive pattern is a thin film solar cell manufacturing method, characterized in that formed with one selected from the group of transparent conductive oxides including indium tin oxide, tin oxide and zinc oxide. The method of claim 8, And a rear transparent conductive pattern and a third light absorbing layer are sequentially stacked in a space between the second light absorbing layer and the reflective electrode.

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