KR20190115382A - Solar cell module and manufacturing method for the same - Google Patents

Abstract

The present invention relates to a photovoltaic module capable of depositing a uniform unit film and having the excellent characteristics of a unit film and cell by a low temperature process and a manufacturing method thereof capable of having the high productivity. According to the photovoltaic module of the present invention, the photovoltaic module comprises: a plurality of tandem photovoltaic cells including an upper photovoltaic cell including a perovskite absorbing layer and a lower photovoltaic cell positioned below the upper photovoltaic cell; bus bar electrodes positioned on the upper and lower photovoltaic cells; and an electro conductive adhesive interconnecting bus bar electrodes of each tandem photovoltaic cell. The photovoltaic module is excellent in the uniformity, photoelectric conversion efficiency, and high productivity.

Description

SOLAR CELL MODULE AND MANUFACTURING METHOD FOR THE SAME

The present invention relates to a solar cell module capable of uniform unit film deposition and excellent unit film and cell characteristics by a low temperature process, and a method for manufacturing a solar cell module having high productivity.

Solar cells are a type of energy conversion device that converts solar energy into electrical energy and are one of the most commercially available alternative energy technologies.

Among them, crystalline silicon (c-Si) solar cells are widely used as commercial solar cells as representative single-junction solar cells.

However, due to the low photoelectric conversion efficiency of crystalline silicon solar cells, development of tandem solar cells constituting one solar cell by connecting single junction solar cells including absorption layers having different band gaps has been actively conducted.

FIG. 1 schematically shows a cross section of a two-terminal tandem solar cell, which is a general form of a tandem solar cell.

Referring to FIG. 1, a solar cell includes tunnel junctions between a single junction solar cell including an absorption layer having a relatively large band gap, and a single junction solar cell including an absorption layer having a relatively small band gap through a junction layer.

Among them, perovskite / crystalline silicon tandem solar cells using a single junction solar cell including a absorption layer having a relatively large band gap as a perovskite solar cell achieve high photoelectric efficiency of 30% or more. I can do it and am attracting much attention.

In such a tandem solar cell, a texture structure is typically formed on the surface of a crystalline silicon substrate to reduce reflectance of incident light. However, when such a texture structure is formed under the tandem solar cell, there is a problem that the perovskite solar cell is not uniformly deposited.

Because the texture structure usually has a size of several tens to several tens of micrometers, while the unit film has a thickness of several tens to hundreds of nm, each unit film has conformal growth that grows with the shape of the substrate or unit film below it. Will be In this case, if the substrate or the underlying film has a texture, uniform formation of the unit layer becomes very difficult due to the Gibbs-Thomson effect at the peak portion of the texture.

Therefore, in the related art, a substrate having a small size may be used for uniform deposition of a perovskite solar cell on a textured substrate. In this case, however, uniform deposition may be possible, but there is a problem in that productivity is remarkably decreased.

On the other hand, commercial solar cells are used as a solar cell module through a packaging process by connecting a plurality of solar cell cells electrically in series or in parallel.

Because each single solar cell does not have sufficient electromotive force from each cell for commercial use.

Conventional crystalline silicon (c-Si) solar cells have been electrically bonded to the busbar and ribbon through soldering in the tabbing step prior to the lamination step.

In recent years, as described above, the perovskite solar cell or the tandem solar cell including the perovskite solar cell has been actively developed and commercialized to improve the low efficiency of the conventional crystalline silicon solar cell.

The perovskite solar cell or tandem solar cell includes a perovskite absorbing layer, which has a disadvantage in that the perovskite absorbing layer is very vulnerable to heat and moisture.

Therefore, in order to prevent thermal decomposition of the perovskite absorbing layer, the solar cell including the perovskite absorbing layer must avoid the high temperature process not only in the solar cell process but also in the subsequent module process.

In particular, in an interconnection process such as a tabbing step included in a conventional crystalline silicon solar cell module manufacturing method, busbar electrodes of respective solar cells are connected to each other by soldering or the like.

However, when the soldering method is used in a method of manufacturing a single solar cell or a tandem solar cell including a perovskite absorbing layer, there is a problem in that decomposition or degradation due to heat of the perovskite absorbing layer is increased.

Therefore, in manufacturing a solar cell module using a perovskite solar cell or a tandem solar cell including the same, it is possible to obtain a unit film having excellent uniformity, high productivity, and prevent breakage of the perovskite absorbing layer by a high temperature process. There is a need for development of a solar cell module and a method of manufacturing the same.

An object of the present invention is to provide a solar cell module made of a unit film having excellent uniformity in a solar cell module composed of a plurality of solar cells.

In addition, an object of the present invention is to provide a solar cell module composed of a plurality of solar cells, in which a decrease in efficiency does not occur by avoiding destruction or degradation of the perovskite absorbing layer by a high temperature process. do.

In addition, the present invention, in order to provide a solar cell module as described above, in order to provide a manufacturing method of a solar cell module that can not only produce a uniform unit membrane in the manufacturing method of the solar cell, but also greatly improved the productivity. do.

In addition, the present invention is to provide a method of manufacturing a solar cell module that can ensure the electrical connection between the solar cells constituting the solar cell module while preventing the destruction or degradation of the perovskite absorbing layer.

According to the tandem solar cell module of the present invention having no damage to the perovskite absorbing layer without undergoing a high temperature module process and excellent in the uniformity and productivity of the unit films constituting the upper solar cell, the upper part including the perovskite absorbing layer A plurality of tandem solar cells including a solar cell and a lower solar cell positioned below the upper solar cell; A bus bar electrode positioned on the upper solar cell and the lower solar cell; A tandem solar cell module may be provided, including; an electrically conductive adhesive interconnecting busbar electrodes of each of the plurality of tandem solar cells.

Preferably, a tandem solar cell module including a wiring member positioned between the electrically conductive adhesive and the busbar electrode may be provided.

Alternatively, the busbar electrodes may be in direct contact with each other; a tandem solar cell module may be provided.

Preferably, the lower cell is a crystalline silicon solar cell; a tandem solar cell module may be provided.

In this case, the crystalline silicon solar cell may be a heterojunction solar cell; a tandem solar cell module may be provided.

Preferably, the electrically conductive adhesive includes at least one adhesive polymer of epoxy, polyurethane, silicone, polyimide, phenol and polyester; A tandem solar cell module including micro, meso or nano-sized dispersed metal particles may be provided.

On the other hand, eutectic mixture located between the bus bar electrode and the wiring material; It can be provided a solar cell module comprising a.

In addition, according to the manufacturing method of the tandem solar cell module according to an embodiment of the present invention to ensure the uniformity and productivity of the unit layers constituting the upper solar cell including a perovskite absorbing layer, the lower solar cell on the substrate Positioning lower solar cell unit membranes constituting the lower portion; Positioning an intermediate layer on the lower solar cell; Positioning the upper solar cell unit films constituting the upper solar cell including a perovskite absorbing layer on the intermediate layer; and in any of the steps of locating the unit films constituting the upper solar cell. A scribing step of dividing the substrate into any mini cell size may be provided.

Preferably, the scribing step is located between any of the steps of forming an electron transporting layer, a perovskite absorbing layer, and a hole transporting layer among the unit films of the upper solar cell. A method of manufacturing a tandem solar cell module may be provided.

In addition, according to the manufacturing method of the tandem solar cell module according to another embodiment of the present invention to ensure the uniformity and productivity of the unit films constituting the upper solar cell including a perovskite absorbing layer, the lower solar cell on the substrate Positioning lower solar cell unit membranes constituting the lower portion; Positioning an intermediate layer on the lower solar cell; Placing upper solar cell unit layers constituting an upper solar cell including a perovskite absorbing layer on the intermediate layer; And scribing the substrate into an arbitrary mini cell size after positioning the upper solar cell, wherein the mask is disposed between the mini cells on the substrate in any of the steps of locating the unit layers constituting the upper solar cell. Masking step of forming a; may be provided a method of manufacturing a tandem solar cell module further comprising.

Preferably, the masking step is located between any of the steps of forming an electron transport layer, a perovskite absorbing layer, a hole transport layer among the unit films of the upper solar cell; A method of manufacturing a tandem solar cell module may be provided.

According to the present invention, deterioration and destruction of the perovskite absorbing layer in the solar cell module can be prevented to reduce the photoelectric conversion efficiency of the tandem solar cell module including the perovskite solar cell.

In addition, it is possible to increase the efficiency of the tandem solar cell module by ensuring uniformity of the unit film.

Furthermore, in the present invention, it is possible to secure the yield of the module by securing the alignment and electrical connection of each unit solar cell in the modularization of the solar cell, furthermore, it is possible to efficiently collect the charge carriers generated in the solar cell The reduction of the effective cross-sectional area can be prevented and the fall of photoelectric conversion efficiency can be avoided.

On the other hand, in the method for manufacturing the tandem solar cell module of the present invention, not only a uniform unit membrane may be manufactured, but also the productivity may be greatly improved compared to a conventional unit cell process.

1 is a schematic view showing a general tandem solar cell.
2 illustrates an embodiment of forming a solar cell constituting the tandem solar cell module including the perovskite absorbing layer of the present invention.
Figure 3 illustrates another embodiment of forming a solar cell constituting the tandem solar cell module including the perovskite absorbing layer of the present invention.
4 is a cross-sectional view of a mask formed on a boundary portion of mini cells for forming a module in a mother substrate of a tandem solar cell module.
Figure 5 shows one embodiment of a cross section of the solar cell module applied to the solar cell module of the present invention.
FIG. 6 is a perspective view schematically illustrating a first solar cell and a second solar cell included in the solar cell module 100 shown in FIG. 5 and connected by a wiring member (for example, a ribbon).
7 is a cross-sectional view illustrating a bonding relationship between a wiring member (for example, a ribbon) and a solar cell.
8 is a cross-sectional view illustrating an example in which two solar cells adjacent to each other among a plurality of solar cells are directly connected without a wiring member.

Hereinafter, a tandem solar cell and a method of manufacturing the same according to a preferred embodiment of the present invention with reference to the accompanying drawings will be described in detail.

The present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, only this embodiment to make the disclosure of the present invention complete and to those skilled in the art to fully understand the scope of the invention It is provided to inform you.

In order to clearly describe the present invention, parts irrelevant to the description are omitted, and like reference numerals designate like elements throughout the specification. In addition, some embodiments of the invention will be described in detail with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same reference numerals as much as possible even though they are shown in different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description may be omitted.

In describing the components of the present invention, terms such as first, second, A, B, (a), and (b) can be used. These terms are only to distinguish the components from other components, and the terms are not limited in nature, order, order or number of the components. If a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected to or connected to that other component, but between components It is to be understood that the elements may be "interposed" or each component may be "connected", "coupled" or "connected" through other components.

In addition, in the implementation of the present invention may be described by subdividing the components for convenience of description, these components may be implemented in one device or module, or one component is a plurality of devices or modules It can also be implemented separately.

< First Example >

Figure 2 shows one first embodiment of forming a solar cell constituting a tandem solar cell module comprising a perovskite absorber layer of the present invention.

First, the tandem solar cell in the present invention includes a solar cell at the bottom and a solar cell at the top. At this time, the lower solar cell is characterized in that the band gap is smaller than the upper solar cell. In the tandem solar cell of FIG. 2, the crystalline silicon silicon cell is exemplified as the lower solar cell, but the lower solar cell of the present invention has a smaller band gap than the upper solar cell and is necessarily limited to the crystalline silicon solar cell. It is not.

As shown in FIG. 2, the substrate is first textured by using the crystalline silicon substrate as a starting material.

More specifically, the crystalline silicon solar cell in the tandem solar cell of the present invention may also have unevenness by texturing to prevent reflection of the first and / or second surface of the silicon substrate. For example, the unevenness may be composed of specific crystal planes. For example, it may have an approximate pyramid shape formed by four outer surfaces which are {111} planes. Because silicon has a face-centered cubic lattice (fcc) in the crystal cubic (diamond cubic), because the {111} plane of the lattice structure is the most stable in the dense plane.

As such, when the unevenness is formed on the surface of the substrate, reflection of light incident on the semiconductor substrate may be prevented, thereby effectively reducing light loss.

Next, the crystalline silicon substrate may be formed of a crystalline semiconductor having a first or second conductivity type by doping the first or second conductivity type dopant, which is a base dopant, at a low doping concentration. For example, the substrate may be composed of a single crystal or polycrystalline semiconductor (eg, single crystal or polycrystalline silicon).

In this case, the crystalline silicon solar cell 110 illustrated as a lower solar cell in the present invention may be implemented as a heterojunction silicon solar cell or a homo-junction silicon solar cell.

As an example, as shown in FIG. 2, the silicon solar cell of the present invention may be implemented as a homo-juction crystalline silicon solar cell. For example, in the case of a homojunction crystalline silicon solar cell having a front emitter layer and a back electric field layer, an impurity doping layer having a different conductivity type from that of the crystalline silicon substrate is used as the emitter layer, and a back surface field is used as the back surface field. By using an impurity doping layer having the same conductivity type as the crystalline silicon substrate, a homojunction crystalline silicon solar cell may be implemented.

Meanwhile, in FIG. 2, the rear field layer is first formed, and then the front emitter layer is formed, but is not necessarily limited thereto. Alternatively, the front emitter layer may be formed first, followed by the back field layer.

Alternatively, the silicon solar cell of the present invention may be implemented as a heterojunction crystalline silicon solar cell.

More specifically, in the case of a heterojunction silicon solar cell, the crystalline silicon solar cell is positioned on the first and / or second surfaces of the crystalline silicon substrate and the first and second surfaces of the crystalline silicon substrate, respectively. A first passivation layer and a second passivation layer; A first conductivity type region located on the first passivation layer; And a second conductivity type region located on the second passivation layer. In this case, the first conductivity type region may be a backside layer or an emitter layer, and the second conductivity type region may be an emitter layer or a backside layer because the second conductivity type has a conductivity type opposite to that of the first conductivity type region.

Next, an intermediate layer (or a tunnel junction layer) is positioned on the emitter layer (eg, a contact), and a lower electrode electrically connected thereto is positioned on the back field layer (eg, a contact).

However, in the present invention, the emitter layer is described and illustrated as being positioned with the intermediate layer (FIG. 2), but is not necessarily limited thereto. As described above, the back surface field (BSF) may be located with the intermediate layer.

First, the lower electrode may further include a lower electrode transparent electrode layer positioned between the rear field layer and the metal electrode layer of the lower electrode.

Here, the lower electrode transparent electrode layer may be entirely formed (for example, contacted) on the rear field layer. Forming as a whole may include not only covering the entire backside layer without any empty space or area, but inevitably when a part is not formed.

As such, when the lower electrode transparent electrode layer is entirely formed on the rear field layer, the carrier can easily reach the metal electrode layer of the lower electrode through the lower electrode transparent field layer, thereby reducing the resistance in the horizontal direction.

In particular, if the rear field layer is made of amorphous silicon, the crystallinity of the rear field layer may be relatively low, and thus the mobility of the carrier may be low. Thus, when the carrier is moved in the horizontal direction with the lower electrode transparent electrode layer, It is to lower the resistance.

Next, the lower electrode metal electrode is positioned on the lower electrode transparent electrode layer. The lower electrode metal electrode layer may be formed after manufacturing the lower solar cell, or may be formed together with the upper electrode metal electrode layer after manufacturing the upper solar cell (see FIG. 2).

In this case, the lower electrode metal electrode layer may include a metal and a crosslinked resin. The lower electrode metal electrode layer may include a metal to improve characteristics such as carrier collection efficiency and resistance reduction. As such, the lower electrode metal electrode layer may have a predetermined pattern to minimize shading loss since the lower electrode metal electrode layer may interfere with the incident light. This allows light to enter the portion where the lower electrode metal electrode layer is not formed.

Next, an intermediate layer is located on the emitter layer.

The intermediate layer of the tandem solar cell of the present invention used a transparent conductive oxide, a carbonaceous conductive material, or a metallic material so that the long-wavelength light that penetrates the upper solar cell can be incident on the lower solar cell without transmitting loss.

Specifically, as the transparent conductive oxide, ITO (Indium Tin Oxide), IWO (Indium Tungsten Oxide), ZITO (Zinc Indium Tin Oxide), ZIO (Zinc Indium Oxide), ZTO (Zinc Tin Oxide), GITO (Gallium Indium Tin Oxide) , GIO (Gallium Indium Oxide), GZO (Gallium Zinc Oxide), AZO (Aluminum doped Zinc Oxide), FTO (Fluorine Tin Oxide) or ZnO.

The upper solar cell is located on the intermediate layer of the present invention.

When the upper solar cell in the present invention is a perovskite solar cell, the second conductivity type charge transport layer (or transfer layer) positioned on the lower solar cell; A perovskite absorber layer on the second conductivity type charge transport layer; A first conductivity type charge transport layer on the perovskite absorber layer 132; And an upper electrode layer positioned on the first conductivity type charge transport layer.

By way of non-limiting example, where the crystalline silicon substrate is an n-type single crystal silicon substrate, the first conductivity type region acts as an emitter layer of a high concentration of amorphous silicon (p + -a-Si: H) layer of p type different from the substrate. The second conductivity type region may be a back surface field (hereinafter referred to as BSF) layer of n type of highly concentrated amorphous silicon (n ⁺ -a-Si: H) layer.

In this case, the second conductivity type charge transport layer in the first solar cell is the same n-type electron transport layer as the second conductivity type region, and the first conductivity type charge transport layer positioned on the perovskite absorption layer 132 is The same p-type hole transport layer 133 as the first conductivity type region 114 is formed. The second solar cell in this arrangement becomes a perovskite solar cell, and among them, it corresponds to a perovskite solar cell having a normal laminated structure.

The first solar cell in the present invention, unlike the previous second solar cell, of any one of the unit processes for forming the first to second conductivity type charge transport layer (or transfer layer) of the first solar cell It is prepared after dividing the substrate before the process.

In the present invention, since the substrate used in the tandem solar cell of the present invention is a crystalline silicon substrate, a scribe process widely used in the semiconductor field may be adopted.

In general, the scribe process refers to a process of making grooves on the surface of a wafer by using a diamond cutter, a laser, or the like to cut the wafer into a plurality of chips.

Therefore, in the present invention, a solar cell standardized as a method for improving the photoelectric conversion efficiency of the solar cell, for example, a solar cell using a pseudo square type semiconductor substrate is divided into several through the above scribing process. To form a small solar cell (hereinafter referred to as a mini cell). Thereafter, the small solar cells are collected and directly or indirectly electrically connected to each other to manufacture the solar cell module of the present invention.

First, as illustrated in FIG. 2, the first solar cell of the present invention may form an electron transport layer after dividing the substrate before the formation of the electron transport layer. Thus, the process in the following examples takes place on each divided unit substrate (i.e. mini cell) rather than the so-called mother substrate.

In the present invention, the electron transport layer may be formed of an electron conductive organic material layer, an electron conductive inorganic material layer, or a layer including silicon (Si).

The electron conductive organic material may be an organic material used as an n-type semiconductor in a conventional solar cell. As a specific and non-limiting example, the electron conductive organic material is fullerene (C ₆₀ , C ₇₀ , C ₇₄ , C ₇₆ , C ₇₈ , C ₈₂ , C ₉₅ ), PCBM ([6,6] -phenyl-C61butyric acid methyl ester )) And fulleren-derivative, polybenzimidazole (PBI), PTCBI (3,4, including C71-PCBM, C84-PCBM, PC70BM ([6,6] -phenyl C70-butyric acid methyl ester) 9,10-perylenetetracarboxylic bisbenzimidazole), F4-TCNQ (tetra uorotetracyanoquinodimethane) or mixtures thereof.

The electron conductive inorganic material may be a metal oxide commonly used for electron transport in a conventional quantum dot based solar cell or a dye-sensitized solar cell. As a specific and non-limiting example, the metal oxide is Ti oxide, Zn oxide, In oxide, Sn oxide, W oxide, Nb oxide, Mo oxide, Mg oxide, Ba oxide, Zr oxide, Sr oxide, Yr oxide, La oxide, One or two or more materials selected from V oxide, Al oxide, Y oxide, Sc oxide, Sm oxide, Ga oxide, In oxide and SrTi oxide may be mentioned, and a mixture thereof or a composite thereof may be mentioned. .

On the other hand, the electron transport layer made of a layer containing silicon (Si), more specifically, amorphous silicon (na-Si), amorphous silicon oxide (na-SiO), amorphous silicon nitride (na-SiN), amorphous silicon carbide ( na-SiC), amorphous silicon oxynitride (na-SiON), amorphous silicon carbonitride (na-SiCN), amorphous silicon germanium (na-SiGe), microcrystalline silicon (n-uc-Si), microcrystalline silicon oxide ( n-uc-SiO), microcrystalline silicon carbide (n-uc-SiC), microcrystalline silicon nitride (n-uc-SiN), microcrystalline silicon germanium (n-uc-SiGe) containing one or more Made of materials.

Next, a perovskite absorbing layer is located on the electron transport layer.

The perovskite absorbing layer in the present invention can be used both so-called MA (Methylamminium) or FA (Formamidinium) -based perovskite compounds widely used at present.

First of all, considering the band gap characteristics, MAPbI ₃ , a typical perovskite compound of MA (Methylamminium) having a band gap of about 1.55 to 1.6 eV, is formed of FA (Formamidinium) having a band gap of about 1.45 eV. Since the band gap is larger than that of MAPbI ₃ , a typical perovskite compound, it is more advantageous because it can absorb light having a short wavelength better.

However, the FA-based perovskite compound also has a unique advantage of superior temperature stability compared to the MA-based perovskite compound. In addition, in recent years, it has been confirmed that the doping of the FA-based perovskite compound with Br increases the band gap of the perovskite compound. In addition, it was confirmed that addition of Cs can suppress the production of unwanted delta (δ) phase FA compounds.

Therefore, in the present invention, when FA (Formamidinium) is used as the perovskite absorbing layer, FA _{1- x} Cs _x PbBr _y I _{3 -y} is more preferable (where 0 = x ≤ = 1, 0 ≤). = y ≤ = 3).

The addition of Br can increase the band gap of the FA-based perovskite absorber layer to a degree similar to that of the existing MA-based perovskite absorber layer. When the band gap energy is increased to a high range, a shorter wavelength of light is absorbed by the perovskite layer having a higher band gap than conventional silicon solar cells, thereby reducing the thermal loss caused by the difference between the photon energy and the band gap, thereby reducing the high voltage. Can be generated. As a result, the efficiency of the solar cell is eventually increased.

The hole transport layer is located on the perovskite absorber layer.

The hole transport layer applicable in the present invention may be formed of a layer including a hole conductive organic material layer, a hole conductive metal oxide, or silicon (Si).

The hole conductive organic material may be used as long as it is an organic hole transport material commonly used for hole transport in a conventional dye-sensitized solar cell or an organic solar cell. As a specific and non-limiting example, the electronic conductive organic material is polyaniline, polypyrrole, polythiophene, poly-3,4-ethylenedioxythiophene-polystyrenesulfonate (PEDOT-PSS), poly- [bis (4-phenyl) (2,4,6-trimethylphenyl) amine] (PTAA), polyaniline-camposulfonic acid (PANI-CSA), pentacene, coumarin 6 (coumarin 6, 3- (2-benzothiazolyl) -7- ( diethylamino) coumarin), zinc phthalocyanine (ZnPC), copper phthalocyanine (CuPC), titanium oxide phthalocyanine (TiOPC), Spiro-MeOTAD (2,2 ', 7,7'-tetrakis (N, Np-dimethoxyphenylamino) -9,9 '-spirobifluorene), F16CuPC (copper (II) 1,2,3,4,8,9,10,11,15,16,17,18,22,23,24,25-hexadecafluoro-29H, 31H-phthalocyanine ), SubPc (boron subphthalocyanine chloride) and N3 (cis-di (thiocyanato) -bis (2,2'-bipyridyl-4,4'-dicarboxylic acid) -ruthenium (II)) It may include.

Metal oxides include Ni oxide, Mo oxide, and V oxide. In this case, the hole transport layer may further include an n-type or p-type dopant, if necessary.

In the present invention, the hole transport layer including silicon (Si), more specifically, amorphous silicon (pa-Si), amorphous silicon oxide (pa-SiO), amorphous silicon nitride (pa-SiN), amorphous silicon carbide (pa -SiC), amorphous silicon oxynitride (pa-SiON), amorphous silicon carbonitride (pa-SiCN), amorphous silicon germanium (pa-SiGe), microcrystalline silicon (p-uc-Si), microcrystalline silicon oxide (p materials comprising one or more of -uc-SiO), microcrystalline silicon carbide (p-uc-SiC), microcrystalline silicon nitride (p-uc-SiN), microcrystalline silicon germanium (p-uc-SiGe) Is made of.

Next, the upper electrode is positioned on the hole transport layer in the present invention.

In this case, the upper electrode first includes an upper electrode transparent electrode layer. The upper electrode transparent electrode layer is formed on the entire upper surface of the perovskite solar cell, and serves to collect charges generated in the perovskite solar cell.

The upper electrode transparent electrode layer may be implemented as various transparent conductive materials. Transparent conductive oxides that can be used as the transparent electrode layer of the upper electrode or the lower electrode include ITO (Indium Tin Oxide), IWO (Indium Tungsten Oxide), ZITO (Zinc Indium Tin Oxide), ZIO (Zinc Indium Oxide), ZTO (Zinc Tin Oxide), GITO (Gallium Indium Tin Oxide), GIO (Gallium Indium Oxide), GZO (Gallium Zinc Oxide), AZO (Aluminum doped Zinc Oxide), FTO (Fluorine Tin Oxide) or ZnO.

Next, the upper electrode metal electrode layer is positioned on the upper electrode transparent electrode layer, and is disposed in a portion of the upper electrode transparent electrode. In addition, as shown in FIG. 2, the lower electrode metal electrode layer may be formed simultaneously with the upper electrode metal electrode layer.

The metal electrode layer of the upper electrode can be prepared by selectively applying a paste containing no glass frit, followed by low temperature baking. Here, the electrode paste for the metal electrode layer of the upper electrode may contain metal particles and an organic material which is a low-temperature baking binder, and the electrode paste for the upper electrode does not include glass frit. In particular, the process temperature of the upper electrode metal electrode may be 250 ° C or less, and more specifically 100 to 200 ° C. This is because the tandem solar cell in the present invention includes a perovskite absorbing layer, because the perovskite absorbing layer is very susceptible to heat and can be decomposed or destroyed by heating.

The tandem solar cell and the module according to the first embodiment of the present invention have the effect of greatly improving productivity in terms of ensuring the quality of the unit membrane as compared to the conventional method of manufacturing the tandem solar cell and the module.

The electron transport layer, the perovskite absorbing layer, and the hole transport layer unit layers constituting the perovskite solar cell are formed on the textured crystalline silicon solar cell with conformal growth or coating properties. This is because the thicknesses of the unit layers are very thin compared to the height of the texture in the substrate or the lower layers. Furthermore, the unit layers are mainly formed by a solution process or the like.

However, the tandem solar cell and the module of the present invention can greatly improve productivity compared to a conventional process using a mini cell by using a crystalline silicon substrate as a parent substrate up to a unit film of a lower second solar cell. In addition, from the unit membrane process of the perovskite solar cell, which is the first solar cell on the upper side, the unit membrane is formed by dividing into mini cells by the scribe process from the desired stage, thereby ensuring the uniform unit membrane property. Can be.

<Example 2>

Figure 3 shows another embodiment of forming a solar cell constituting a tandem solar cell module comprising a perovskite absorbing layer of the present invention.

The difference between FIG. 3 and FIG. 2 lies in at what stage the scribe process is performed.

Specifically, in Example 1 of FIG. 2, the scribing process is performed among the unit membrane processes of the perovskite solar cell as the first solar cell. In contrast, in Example 2 of FIG. 3, a scribe process is performed after forming the entire tandem solar cell including the first solar cell.

Therefore, the second embodiment shown in FIG. 3 has the advantage that the productivity of the tandem solar cell and the module is higher than that of the first embodiment shown in FIG. 2. However, the unit membranes of the tandem solar cells (particularly perovskite solar cells) according to the second embodiment of FIG. 3 may have a lower uniformity than the prior art or the first embodiment.

In the present invention, in order to secure the uniformity of the unit films constituting the perovskite solar cell in Example 2, as shown in Figure 4, before forming the perovskite solar cell on top of the tandem solar cell A mask is formed at the boundary of mini cells for module formation in the parent substrate.

The forming of the mask may be added as needed between the intermediate layer or the hole transport layer deposition step among the manufacturing processes of Embodiment 2 of FIG. 3. Each of the unit film processes constituting the perovskite solar cell, as described in detail in Example 1 above, is commonly used as a solution process, but a thin film process may also be used if necessary. Therefore, in the mask forming step of the present invention, as in the scribing process of Example 1, the uniformity and productivity are secured at the same time as it is positioned before the most uniform process among the unit films of the perovskite solar cell. It is possible.

On the other hand, the process of forming the mask in Example 2 of the present invention can significantly reduce the lead time, which is a process time per unit process as well as the number of processes compared to the scribe process.

For example, if n mini cells are formed through a scribe process on one mother substrate, the unit process is performed n times in each of several mini cells, and the n mini cells on the mother substrate are separated by a mask. There are many differences in the process time of the unit process to proceed the unit process n times.

If n mini-cells are formed through a scribing process and n unit film processes are performed, n substrate transfer and alignment are necessary. If the unit process is a thin film process, additional equipment or time for maintaining the vacuum is required.

On the other hand, when the unit membrane process is performed after masking the compartments for the n mini cells through the mask process, only the transfer and alignment of the first substrate is necessary.

Therefore, the tandem solar cell and the module and the method of manufacturing the same according to the second embodiment of the present invention have excellent uniformity of the unit film, so that not only the photoelectric change efficiency is excellent but also the productivity is very excellent compared to the prior art.

Tandem solar cell modularization

A plurality of tandem solar cells manufactured by the above Examples 1 and 2 are used as solar cell modules through a modulation process in which a plurality of electrically connected in series or in parallel.

Because each single solar cell is not sufficient for commercial use of the electromotive force generated in each cell.

In the case of a conventional crystalline silicon (c-Si) solar cell, the bus electrode or busbar electrode and the ribbon are electrically bonded through soldering in the tabbing step before the lamination step.

By the way, in the tandem solar cell of the present invention includes a perovskite absorbing layer, the perovskite absorbing layer is characterized by being very susceptible to heat and moisture.

Specifically, it is reported that the perovskite material is particularly weak at high temperatures, and deteriorates the cell by decomposing the CH ₃ NH ₃ PbI ₃ light absorbing layer after 3 hours at 150 ° C. or higher even in a vacuum. On the other hand, it is reported that the atmosphere is maintained in a vacuum, N ₂ , O ₂ atmosphere even after exposure to 24 hours at 85 ℃. This means that the perovskite unit membrane adopted in the present invention is very susceptible to heat, and even during the module process, a low temperature process adjusted to not exceed 150 ° C. should be performed.

Therefore, in order to prevent thermal decomposition of the perovskite absorbing layer, the solar cell including the perovskite absorbing layer must avoid the high temperature process not only in the solar cell process but also in the subsequent module process.

This means that the high temperature soldering process in the tabbing step included in the conventional crystalline silicon solar cell module manufacturing method can no longer be used in a solar cell including a perovskite absorber layer.

On the other hand, the alignment between the busbar electrode in each solar cell and the ribbon connecting the solar cells is a very important factor in determining the yield of the solar cell module process. If the alignment between the busbar electrode and the ribbon is misaligned, the photovoltaic conversion due to the reduction of the effective surface area is not possible because the carriers of the solar cells are not efficiently collected and the surface of the ribbon is not absorbed by the sun. This is because it causes a decrease in efficiency.

Therefore, in the present invention, when modularizing the mini-cells of the tandem solar cells in Examples 1 and 2, a tandem solar cell that can ensure the alignment of the solar cell mini-cells without applying a high temperature process, to ensure photoelectric conversion efficiency Modules and modularization schemes were developed.

Figure 5 shows one embodiment of a cross section of a solar cell module that can be applied to the solar cell module of the present invention.

As shown in FIG. 5, the solar cell module 100 of the present invention includes a plurality of solar cells 150 and a wiring member 142 (eg, a ribbon) for electrically connecting the plurality of solar cells 150. do. The solar cell module 100 includes an encapsulant 130 including a first encapsulant 131 and a second encapsulant 132 that enclose and seal a plurality of solar cells 150 and a wiring member 142 connecting thereto. And a first protection member 110 positioned on the first surface of the solar cell 150 on the encapsulant 130 and a second protection positioned on a second surface of the solar cell 150 on the encapsulant 130. Member 120.

Each of the plurality of solar cells 150 in the present invention corresponds to a mini cell whose size is determined in the scribing step.

In this case, the first protective member 110 and the second protective member 120 may be formed of an insulating material that can protect the solar cell 150 from external impact, moisture, ultraviolet rays, and the like.

Meanwhile, the first protective member 110 may be made of a light transmissive material, and the second protective member 120 may be made of a sheet made of a light transmissive material, a non-transparent material, a reflective material, or the like. For example, the first protective member 110 may be formed of a glass substrate, etc., and the second protective member 120 may have a TPT (Tedlar / PET / Tedlar) type, or a glass or a base film (for example, It may include a poly vinylidene fluoride (PVDF) resin layer formed on at least one surface of polyethylene terephthalate (PET).

At this time, the first protective member 110 mainly uses so-called white glass, in which the content of iron (Fe) is lowered to increase the transmittance of sunlight, particularly the wavelength in the range of 380 to 1,100 nm. In addition, the glass for the front glass plate 110 may be strengthened if necessary to protect the solar cell 150 from impact or foreign matter from the outside.

The plurality of solar cells 150 cells in the present invention may be electrically connected in series, parallel or in parallel by the wiring member 142, in particular for the electrical connection method is not limited in the present invention.

FIG. 6 is a perspective view schematically illustrating the first solar cell 151 and the second solar cell 152 included in the solar cell module 100 shown in FIG. 5 and connected by the wiring member 142.

5 and 6, two solar cells 150 (for example, the first solar cell 151 and the second solar cell 152) adjacent to each other among the plurality of solar cells 150 are wiring members 142. ) Can be connected.

In this case, the wiring member 142 includes the upper electrode 42 located on the front surface of the first solar cell 151 and the second solar cell 152 positioned on one side (lower left side of the drawing) of the first solar cell 151. Connect the lower electrode 44 located on the back of the. In addition, another wiring member 1420a is disposed on the lower electrode 44 located on the rear surface of the first solar cell 151 and on the front surface of another solar cell to be located on the other side of the first solar cell 151 (right side of the drawing). The electrode 42 is connected. And another wiring member 1420b is located on the upper electrode 42 located on the front of the second solar cell 152 and on the back of another solar cell to be located on one side (left side of the drawing) of the second solar cell 152. The second electrode 44 is connected. As a result, the plurality of solar cells 150 may be connected to each other by one wire by the wiring members 142, 1420a, and 1420b.

In this case, the width W1 of the wiring member 142 may be smaller than the pitch of the finger line 427, which is an electrode facing in the direction perpendicular to the wiring member direction in FIG. 6, and may be larger than the width of the finger line 427. . However, the present invention is not limited thereto and various modifications are possible.

7 is a cross-sectional view illustrating a bonding relationship between a wiring member and a solar cell.

As shown in FIG. 7, the solar cell of the present invention includes an electro-conductive adhesive between the busbar electrodes and the wiring members on the transparent electrode layer positioned on the front or rear surface of the solar cell. It is modularized by placing the ECA) to fix the busbar electrodes and the wiring members.

The electrically conductive adhesive is a mixture of micro, meso or nano-sized metal particles dispersed in an adhesive polymer such as epoxy, polyurethane, silicone, polyimide, phenol or polyester. to be. In this case, the metal particles may include silver, copper, aluminum, tin, or alloys thereof.

Subsequently, a subsequent low temperature subsequent process (eg lamination process) of 150 ° C. or less may be performed as necessary. If a low temperature subsequent process is performed, most of the organics, including the polymers that make up the electrically conductive adhesive, are burned out, and the remaining conductive metal particles react with the wiring material by diffusion to form an intermetallic compound. Eutectic mixtures may be newly formed. Since the eutectic mixture is made of a metal main component, it is possible to further increase the adhesion and electrical conductivity between the busbar electrode and the wiring material.

On the other hand, the first encapsulant 131 and the second encapsulant 132 prevents the inflow of moisture and oxygen and chemically combines the elements of the solar cell module 100. The first and second encapsulation materials 131 and 132 may be made of an insulating material having transparency and adhesion. For example, ethylene vinyl acetate copolymer resin (EVA), polyvinyl butyral, silicon resin, ester resin, olefin resin, and the like may be used as the first encapsulant 131 and the second encapsulant 132.

The second protective member 120, the second encapsulant 132, the solar cell 150, the first encapsulant 131, and the first by a lamination process using the first and second encapsulants 131 and 132. The protection member 110 may be integrated to form the solar cell module 100.

Through the low temperature modularization process using the electrically conductive adhesive, the tandem solar cell of the present invention can be manufactured as a module. In addition, the tandem solar cell of the present invention manufactured by such a method prevents degradation of the perovskite unit film through a low temperature process, thereby avoiding a decrease in photoelectric conversion efficiency.

8 is a cross-sectional view illustrating another example of the modularization process of the present invention, in which two solar cells adjacent to each other among a plurality of solar cells 150 are connected without a wiring material.

As shown in Figure 8, the mini-cell type solar cells of the present invention is shown that the bus bars located in the front or rear of each cell is directly connected by an electrically conductive adhesive (ECA), without a separate wiring material It is. The electrically conductive adhesive at this time is substantially the same as the electrically conductive adhesive used in FIG. 7 above.

The modularization method as shown in FIG. 8 can be modularized without a wiring material, so that the economical efficiency is high, and furthermore, since the area of the solar cell per unit area can be more compactly arranged, the power per unit area can be increased.

As described above, the present invention has been described with reference to the drawings, but the present invention is not limited to the embodiments and drawings disclosed herein, and various modifications may be made by those skilled in the art within the scope of the technical idea of the present invention. It is obvious that modifications can be made. In addition, even if the above described embodiments of the present invention while not explicitly described and described the operation and effect according to the configuration of the present invention, it is obvious that the effect predictable by the configuration also to be recognized.

Claims (11)

A plurality of tandem solar cells including an upper solar cell including a perovskite absorbing layer and a lower solar cell positioned below the upper solar cell;
A bus bar electrode positioned on the upper solar cell and the lower solar cell;
An electrically conductive adhesive interconnecting busbar electrodes of each of said plurality of tandem solar cells;
Tandem solar cell module comprising a. The method of claim 1,
A wiring member positioned between the electrically conductive adhesive and the busbar electrode;
Tandem solar cell module comprising a. The method of claim 1,
The busbar electrodes are in direct contact with each other;
Tandem solar cell module characterized in that. The method of claim 1,
The lower cell is a crystalline silicon solar cell;
Tandem solar cell module characterized in that. The method of claim 4, wherein
The crystalline silicon solar cell is a hetero junction solar cell;
Solar cell module characterized in that. The method of claim 1,
The electrically conductive adhesive may include at least one adhesive polymer of epoxy, polyurethane, silicone, polyimide, phenol, and polyester;
Dispersed metal particles of micro, meso or nano size;
Tandem solar cell module comprising a. The method of claim 2,
A eutectic mixture located between the busbar electrode and the wiring member;
Solar cell module comprising a. Positioning lower solar cell unit layers constituting the lower solar cell on a substrate;
Positioning an intermediate layer on the lower solar cell;
And placing upper solar cell unit layers constituting the upper solar cell including a perovskite absorbing layer on the intermediate layer.
A scribe step of dividing the substrate into an arbitrary mini-cell size in any of the steps of locating the unit films constituting the upper solar cell;
Method of manufacturing a tandem solar cell module further comprising. The method of claim 8,
The scribing step may be located between any of the steps of forming an electron transport layer, a perovskite absorber layer, and a hole transport layer among unit films of the upper solar cell;
Method of manufacturing a tandem solar cell module, characterized in that. Positioning lower solar cell unit layers constituting the lower solar cell on a substrate;
Positioning an intermediate layer on the lower solar cell;
Placing upper solar cell unit layers constituting an upper solar cell including a perovskite absorbing layer on the intermediate layer;
Scribing the substrate to an arbitrary mini cell size after positioning the upper solar cell;
A masking step of forming a mask between the mini cells on the substrate in any of the steps of locating the unit layers constituting the upper solar cell;
Method of manufacturing a tandem solar cell module further comprising. The method of claim 10,
The masking step may be located between any of the steps of forming an electron transporting layer, a perovskite absorbing layer, and a hole transporting layer among the unit layers of the upper solar cell;
Method of manufacturing a tandem solar cell module, characterized in that.

Images