KR102524021B1 - Well aligned solar cell module and manufacturing method for the same - Google Patents

Abstract

The present invention relates to a solar cell module that does not require a high-temperature pretreatment process, thereby preventing damage to the solar cell and capable of soldering simultaneously with lamination, and a manufacturing method thereof.
According to the method for manufacturing a solar cell module of the present invention, an alignment step of aligning corresponding wiring members on each electrode of solar cells including a perovskite layer; temporarily fixing the conductive wiring members on the solar cell; a string step of forming a string by arranging a plurality of solar cells to which the conductive wiring material is temporarily fixed; A lay-up step of arranging the solar cell string between sealants; By providing a method for manufacturing a solar cell module comprising: bonding the arrayed solar cell cells at a temperature of 150° C. or less through a laminator and electrically bonding the wiring material to the solar cell at a low temperature. , the effect of maintaining excellent photoelectric conversion efficiency in the module can be obtained.

Description

Solar cell module with excellent alignment and manufacturing method thereof {WELL ALIGNED SOLAR CELL MODULE AND MANUFACTURING METHOD FOR THE SAME}

The present invention relates to a solar cell module with improved productivity due to excellent alignment and a method for manufacturing the same.

A solar cell is a type of energy conversion device that converts sunlight energy into electrical energy, and is currently one of the most commercialized alternative energy technologies.

A commercial solar cell is used as a solar cell module by electrically connecting a plurality of solar cells in series or parallel and going through a packaging process.

This is because the electromotive force generated by each single solar cell is not sufficient for commercial use.

In order to manufacture such a solar cell module, a tabbing step of bonding ribbons to both sides of each solar cell and a step of manufacturing a string by connecting the cells with a ribbon are performed. Thereafter, after locating the stringed cell array on the sealing material, an array step of electrically connecting each string, a module setting step of covering the sealing material and the back sheet, and then a lamination step are performed.

The neck process that determines the yield in the general module manufacturing step is a tabbing step.

Basically, the tabbing step is a step of electrically bonding each solar cell with a ribbon. More specifically, in the tabbing step, after adjusting the alignment of each cell of the inspected solar cell, applying flux, connecting the ribbon to the bus bar, the soldering alloy layer is melted through soldering, and the ribbon and the bus bar are soldered. do.

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

Recently, in order to improve the low efficiency of conventional crystalline silicon solar cells, perovskite solar cells or tandem solar cells including the perovskite solar cells have been actively developed and commercialized.

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

Therefore, a solar cell including a perovskite absorber layer must avoid a high-temperature process not only in a solar cell process but also in a subsequent module process in order to prevent decomposition of the perovskite absorber layer due to heat.

In particular, the high-temperature soldering process in the tabbing step included in the conventional method of manufacturing a crystalline silicon solar cell module is no longer usable in the method of manufacturing a solar cell including a perovskite absorber layer.

Meanwhile, the alignment between the bus bar electrode and the ribbon in the tabbing step is a very important factor in determining the yield of the solar cell module process. This is because, if the bus bar electrode and the ribbon are not aligned, the charge carriers generated by the solar cell cannot be efficiently collected, and the lower surface of the ribbon does not absorb sunlight, resulting in photoelectric conversion due to the decrease in effective surface area. This is because it causes a decrease in efficiency.

In order to improve the photoelectric conversion efficiency of solar cells, many improvements are continuously required not only at the solar cell level but also at the module level.

In particular, recently, efforts have been made to increase the photoelectric conversion efficiency of the solar cell module by minimizing the decrease in the effective surface area of the solar cell module. As one of these efforts, the line width of bus bar electrodes continues to decrease. This requires more precise alignment of the busbar electrode and ribbon.

A technique for maximizing the surface area capable of absorbing light in a solar cell module and transporting the charge carriers collected in the solar cell to the outside with lower resistance is continuously required. This is because these technologies can further expand the commercialization and market of solar cells by improving the photoelectric conversion efficiency of the solar cell module as well as improving productivity in the module process.

As a prior art related to the present invention, there is Korean Patent Registration No. 10-1305087 (registered on September 10, 2013). The above patent discloses a tabbing method and device in the process of modularizing a solar cell.

The present invention relates to a solar cell module composed of a plurality of solar cells and a manufacturing method, which do not require a high-temperature pretreatment process, thereby preventing damage to the solar cell and enabling soldering at the same time as lamination to improve productivity. It is an object of the present invention to provide a solar cell module and a manufacturing method thereof.

In addition, an object of the present invention is to provide a solar cell module capable of preventing deterioration of a solar cell by applying a low-temperature lamination process and a manufacturing method thereof.

In addition, an object of the present invention is to provide a solar cell module capable of preventing module failure and effective surface area reduction by providing precise alignment between a bus bar electrode and a wiring member, and a manufacturing method thereof.

Furthermore, another object of the present invention is to provide a solar cell module capable of maximally suppressing a decrease in effective surface area and, as a result, suppressing a decrease in appearance defects and short-circuit current, and a manufacturing method thereof.

It does not require a high-temperature pretreatment process, and can prevent solar cell damage through low-temperature lamination, and also can solder at the same time as lamination, and provides precise alignment between bus bar electrodes and wiring materials. According to the manufacturing method of a solar cell module of the present invention capable of preventing module failure, an alignment step of aligning corresponding wiring members on each electrode of solar cells including a perovskite layer; temporarily fixing the conductive wiring members on the solar cell; a string step of forming a string by arranging a plurality of solar cells to which the conductive wiring material is temporarily fixed; A lay-up step of arranging the solar cell string between sealants; A low-temperature lamination step of bonding the arrayed solar cells at a temperature of 150° C. or less through a laminator and electrically bonding the wiring material to the solar cell; can

Preferably, the temporary fixing step is a step of attaching and fixing a temporary fixing tape on the wiring members arranged in a series in a direction crossing the longitudinal direction of the wiring members; manufacturing a solar cell module, characterized in that A method may be provided.

Alternatively, the temporary fixing step is a step of fixing with an electro conductive adhesive (ECA) positioned between each of the line members and the bus bars aligned in a series; manufacture of a solar cell module, characterized in that A method may be provided.

At this time, the electrically conductive adhesive is discontinuously positioned in the longitudinal direction of the wiring members; a method for manufacturing a solar cell module may be provided.

In particular, a method for manufacturing a solar cell module may be provided, wherein a ratio of the length of the electrically conductive adhesive in the longitudinal direction of the wiring members is 1 to 25%.

Alternatively, a method for manufacturing a solar cell module may be provided, wherein the electrically conductive adhesive is continuously positioned in the longitudinal direction of the wiring members.

In addition, in the present invention, according to the solar cell module of the present invention, which can suppress the decrease in effective surface area to the maximum, and as a result, the appearance defect and the decrease in short-circuit current can be suppressed, the perovskite layer, the first electrode, and the second electrode A plurality of solar cells including; A plurality of wiring members electrically connected to the first and second electrodes of adjacent cells among the plurality of solar cells, and an electrically conductive adhesive layer present at an interface between the electrode and the wiring member. A characterized solar cell module may be provided.

Preferably, the ratio of the length of the electrically conductive adhesive layer in the longitudinal direction of the wiring members is 1 to 25%; a solar cell module may be provided.

Alternatively, the electrically conductive adhesive layer is continuously positioned in the longitudinal direction of the wiring members; a solar cell module may be provided.

Alternatively, a eutectic mixture exists between the electrically conductive adhesive layers discontinuously positioned in the longitudinal direction of the wiring members; a solar cell module may be provided.

Preferably, a width of the electrically conductive adhesive layer is smaller than a width of the electrode; a solar cell module may be provided.

Preferably, the wiring member has a circular, elliptical or polygonal cross section; a solar cell module may be provided.

Preferably, the solar cell is a perovskite solar cell or a tandem solar cell including a perovskite solar cell; a solar cell module may be provided.

According to the present invention, in the method of manufacturing a solar cell module, a high-temperature pretreatment process is not required and a low-temperature lamination process is applied, thereby preventing damage or deterioration of the solar cell due to heat. Due to this, the solar cell module of the present invention does not cause a decrease in the photoelectric conversion efficiency of the solar cell, and can maintain excellent photoelectric conversion efficiency in the module.

In addition, in the solar cell module manufacturing method of the present invention, soldering may be performed simultaneously with lamination. As a result, the solar cell module of the present invention has the advantage of high productivity by reducing the total production time (tact time).

In addition, the solar cell module manufacturing method according to the present invention can provide precise alignment between the electrode and the wiring member. Therefore, the manufacturing method of the present invention can prevent module failure and improve productivity by increasing process yield. In addition, it is possible to obtain an effect of increasing the photoelectric conversion efficiency of the solar cell module by preventing a decrease in the effective surface area of the solar cell due to misalignment.

Furthermore, in the solar cell module and its manufacturing method according to the present invention, no loss of effective surface area of the solar cell occurs except for electrodes and wiring materials. As a result, it is possible to have an effect capable of suppressing a decrease in appearance defects and short-circuit current of the solar cell module.

1 is a schematic perspective view of a general solar cell module including the present invention.
FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1 .
3 is a process chart schematically showing a conventional manufacturing method of a solar cell module.
4 is a process chart schematically showing a method for manufacturing a solar cell module according to the present invention.
Figure 5 shows a temporarily fixed state of the wiring members aligned using a temporary fixing tape in the temporary fixing step of the present invention.
6 illustrates a temporarily fixed state of aligned wiring members by discontinuously applying an electrically conductive adhesive, which is another embodiment of the present invention.
FIG. 7 shows a temporarily fixed state of aligned wiring members by continuously applying an electrically conductive adhesive, which is another embodiment of the present invention.
8 illustrates a connection state after lamination of aligned wiring members using an electrically conductive adhesive, which is another embodiment of the present invention.
9 shows wiring members having various cross-sectional shapes used in the present invention.
10 is a binary system phase diagram of silver (Ag) and antimony (Sb).
11 is a binary system phase diagram of silver (Ag) and tin (Sn).
12 is a cross-sectional view showing a solar cell and module according to the present invention.

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

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

In order to clearly describe the present invention, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification. In addition, some embodiments of the present invention are described in detail with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same numerals as much as possible even if they are displayed on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related 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) may be used. These terms are only used to distinguish the component from other components, and the nature, sequence, order, or number of the corresponding component is not limited by the term. When an element is described as being “connected,” “coupled to,” or “connected” to another element, that element is or may be directly connected to that other element, but intervenes between each element. It will be understood that may be "interposed", or each component may be "connected", "coupled" or "connected" through other components.

In addition, in implementing the present invention, components may be subdivided for convenience of explanation, but these components may be implemented in one device or module, or one component may be implemented in a plurality of devices or modules. It may be divided into and implemented.

FIG. 1 is a perspective view showing a general solar cell module including the present invention, and FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1 .

Referring to FIGS. 1 and 2 , the solar cell module 100 includes a plurality of solar cells 150 and a wiring member 142 electrically connecting the plurality of solar cells 150 to each other. In addition, the solar cell module 100 includes an encapsulant 130 including a first encapsulant 131 and a second encapsulant 132 that enclose and seal the plurality of solar cells 150 and the wiring member 142 connecting them. And, the first protection member 110 positioned on the first surface of the solar cell 150 on the encapsulant 130 and the second protection positioned on the second surface of the solar cell 150 on the encapsulant 130 It includes member 120.

In this case, each of the first protective member 110 and the second protective member 120 may be made of an insulating material capable of protecting the solar cell 150 from external shock, moisture, ultraviolet rays, and the like.

Meanwhile, the first protective member 110 may be made of a light-transmitting material through which light may pass, and the second protective member 120 may be made of a sheet made of a light-transmitting material, a non-transmissive material, or a reflective material. For example, the first protective member 110 may be composed of a glass substrate, etc., and the second protective member 120 may have a TPT (Tedlar/PET/Tedlar) type, Glass or a base film (eg, It may include a polyvinylidene 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 having a low content of iron (Fe) to increase transmittance of sunlight, particularly sunlight in a wavelength range of 380 to 1,100 nm. In addition, the glass for the front glass plate 110 may be tempered, if necessary, to protect the solar cell 150 from impact or foreign matter from the outside.

When both the first and second protective members are made of a transparent material, the amount of power generation can be increased because light is received from both sides.

The plurality of solar cells 150 in the present invention may be electrically connected in series, parallel, or series-parallel by the wiring member 142, and the present invention does not specifically limit the electrical connection method. The wiring member 142 and the solar cell 150 will be described in more detail later.

The bus ribbon 145 is connected by a wiring member 142 to alternately connect both ends of the wiring member 142 of the solar cell 150 (ie, a solar cell string) forming one row do. The bus ribbon 145 may be disposed at an end of the solar cell string in a direction crossing it. The bus ribbon 145 may connect adjacent solar cell strings or may connect the solar cell strings or the solar cell strings to a junction box (not shown) preventing reverse current flow. The material, shape, and connection structure of the bus ribbon 145 may be variously modified, and the present invention is not limited thereto.

1 and 2, the encapsulant 130 includes the first encapsulant 131 positioned on the first surface of the solar cell 150 connected by the wiring member 142, and the first encapsulant 131 of the solar cell 150. It may include a second encapsulant 132 located on two sides.

The first encapsulant 131 and the second encapsulant 132 prevent moisture and oxygen from entering and chemically combine each element of the solar cell module 100 . The first and second encapsulants 131 and 132 may be made of an insulating material having light-transmitting and adhesive properties. For example, ethylene-vinyl acetate copolymer resin (EVA), polyvinyl butyral, silicon resin, ester-based resin, or olefin-based resin may be used as the first encapsulant 131 and the second encapsulant 132 .

The second protection member 120, the second encapsulant 132, the solar cell 150, the first encapsulant 131, the first encapsulant 131, the first The protective member 110 may be integrated to form the solar cell module 100 . A manufacturing method of the solar cell module 100 will be described in more detail below.

3 is a process diagram schematically illustrating a manufacturing method of a conventional solar cell module.

As shown in FIG. 3, first, corresponding wiring members are aligned on each electrode of solar cells classified by grade based on efficiency and color by cell inspection (S100).

In each of the solar cells classified as follows, wiring materials are bonded to both sides including the light-receiving surface and the opposite surface in the tabbing step (S200). At this time, when the wiring member is heated after being connected to the bus bar electrode, the soldering alloy layer of the wiring member is melted and the wiring member and the bus bar electrode are soldered.

Next, in a string step (S300) and a lay-up step (S400), a string is formed by serially connecting the solar cells to which the wiring member is bonded. Thereafter, the solar cell string is placed in a plurality of rows between the sealants 131 and 132 positioned on the first protective member 110 and the second protective member 120, and then each string is electrically connected.

Next, in the lamination step (S500), the string covered with the sealant is compressed and heated in a vacuum at a sufficiently high temperature to fix the first protective member, the sealant, the solar cell, the sealant, and the second protective member.

Meanwhile, as described above, in the conventional general solar cell module manufacturing method, the wiring material and the bus bar electrode are fixed through high-temperature soldering in the tabbing step. However, since the solar cell in the present invention is very vulnerable to heat, it is difficult to apply the conventional module manufacturing method including high-temperature soldering.

On the other hand, if the wiring member and the bus bar electrode are not fixed to each other, this causes a failure in the module process. More specifically, if the alignment between the bus bar electrode and the wiring material is not precisely matched and electrical contact is made and then laminated, the charge carriers generated in the solar cell cannot be efficiently collected, and the charge carriers cannot be efficiently collected. A misaligned wiring material does not transmit sunlight and thus reduces the effective surface area of the solar cell. In addition, such a problem eventually causes not only a decrease in the photoelectric conversion efficiency of the solar cell module, but also a failure in severe cases, resulting in a decrease in module yield.

In particular, in recent years, in order to minimize the decrease in the effective surface area of the solar cell due to the wiring material, the line width of the bus bar electrode and the wiring material is gradually decreasing. Therefore, the accuracy of alignment between the bus bar electrode and the wiring member is further required.

4 schematically illustrates a manufacturing method of a solar cell module in the present invention.

In the method for manufacturing a solar cell module in the present invention, a heating process is not included before the lamination step (S' 500), and in addition, the lamination step (S' 500) is performed at a low temperature of 150 ° C. or less. . In the manufacturing method of the solar cell module of the present invention, which is more specific, it includes a temporary fixing step (S' 200) after the cell inspection step (S 100), and a low-temperature lamination step (S'' 500). to be The low temperature lamination step (S″ 500) in the present invention will be described later.

The temporary fixing step in the present invention refers to a step of temporarily fixing the bus bar electrode and the wiring material before the lamination step without a separate high-temperature process.

The reason why the heating process is not included before the low-temperature lamination step (S′ 500) in the present invention is that the solar cells used in the present invention are solar cells that have improved the low photoelectric conversion efficiency of conventional crystalline silicon solar cells.

In particular, a tandem solar cell including a perovskite solar cell or a perovskite solar cell including an organic/inorganic perovskite absorber layer adopted in the present invention, and a high efficiency HIT (hetero solar cell) among conventional crystalline silicon solar cells -junction with intrinsic thin film) In the case of a solar cell, a low-temperature process is essential.

This is because the perovskite absorbing layer is very vulnerable to heat and moisture, and the perovskite absorbing layer is decomposed by heat in a manufacturing process at a high temperature of 200° C. or higher.

Meanwhile, in the HIT silicon solar cell, there are many defects or broken silicon bonds in the amorphous silicon buffer layer. In order to stabilize the defects or broken bonds, an intrinsic amorphous silicon buffer layer (i-a-Si:H) to which hydrogen is added as a dopant is used. However, if a high-temperature process of 200° C. or higher is included in a subsequent process, hydrogen in the doped buffer layer escapes from the buffer layer by diffusion. After all, a low-temperature process is an essential process even in a HIT silicon solar cell or a tandem solar cell including the same.

Therefore, in the method of manufacturing a module using such a high-efficiency solar cell, a high-temperature process of 150° C. or higher should be avoided as much as possible.

Temporarily fixing the bus bar electrode and the wiring member in the present invention can be implemented through various processes.

5 shows a state in which wiring members aligned with respect to the bus bar electrode are temporarily fixed using a temporary fixing tape, which is one aspect of the temporarily fixing step in the present invention.

In the present invention, first, after aligning the wiring members on the bus bar electrodes, the wiring members on the bus bar electrodes are temporarily fixed using a temporary fixing tape. The term "temporarily fixed" rather than "fixed" is used in the present invention because mechanically and/or electrically completely fixing the bus bar electrode and the wiring member proceeds through soldering in the subsequent lamination step.

At this time, the temporarily fixing tape in the present invention preferably temporarily fixes the wiring members in a direction crossing the longitudinal direction of the wiring member on the wiring member.

If the temporary fixing tape temporarily fixes the wiring member in the longitudinal direction of the wiring member, the portion of the temporary fixing tape located on the surface of the solar cell becomes excessively large. When the surface area occupied by the temporary fixing tape increases, this eventually causes a decrease in the area capable of absorbing sunlight on the surface of the solar cell, resulting in adverse effects on the photoelectric conversion efficiency of the solar cell module.

In addition, when the temporary fixing tape temporarily fixes the wiring members in a direction crossing the longitudinal direction on the wiring member, a plurality of wiring members can be temporarily fixed at once, thereby improving productivity through reduction of lead time. .

On the other hand, the fixed tape in the present invention is preferably made of a material with excellent solar transmittance. In addition, since the positions of the wiring members must be stably fixed even in the subsequent lamination step (S' 500), it is more preferable that the wiring members have high temperature resistance and adhesiveness.

As a non-limiting example of the material of the temporarily fixed tape, the base of the tape may be PE (polyethylene), PP (polypropylene), PET (polyethylene terephthalate), PVC (polyvinyl chloride), and the like. In addition, the adhesive can be used to produce a temporary fixing tape having transparency, insulation, and adhesive properties using acrylic, cellulose, or silicone-based resins.

Meanwhile, although FIG. 5 shows that three bus bar electrodes are located in one solar cell as an example, it is not necessarily limited thereto. In principle, one or more bus bar electrodes are located in one solar cell. In addition, as many wiring members as the number corresponding to the bus bar electrodes are positioned.

Referring back to FIG. 5 , the plurality of wiring members 142 in FIG. 5 are disposed at regular intervals within each solar cell constituting the module as well as within the solar cell module. As a non-limiting example, the number of wiring members 142 per cell may be 1 to 38.

On the other hand, the wiring member has mechanical dimensions. In particular, the width of the wiring member is matched with the number and shape of the wiring member, and thus affects not only adhesiveness with the bus bar electrode but also absorption and reflection of sunlight in the solar cell module, which will be described later.

The width W1 of the wiring member is preferably 0.5 to 1.5 mm when the number of wiring members is about 1 to 5 per cell. On the other hand, when the number of wiring members per cell is 6 or more, the width of the wiring member is preferably 250 to 500 um.

Specifically, if the width (W1) of the wiring member 142 is less than 250um, the strength of the wiring member 142 may not be sufficient, and the connection area with the bus bar electrode is very small, resulting in poor electrical connection characteristics and low adhesion. there is. On the other hand, if the width W1 of the wiring members 142 exceeds 500 um, the cost of the wiring members 142 increases and the wiring members 142 interfere with light incident on the front surface of the solar cell 150, causing light loss (shading). loss) may increase. In addition, since the force applied from the wiring members 142 in a direction away from the bus bar electrode increases, the adhesion between the wiring members 142 and the bus bar electrode may be low, and cracks may occur in the bus bar electrode or the semiconductor substrate 150. can cause problems.

6 and 7 show a temporarily fixed state of aligned wiring members using an electrically conductive adhesive, which is another embodiment of the present invention. In FIG. 6, (a) and (b) show shapes in which the electrically conductive adhesive is applied discontinuously, and (a) and (b) in FIG. 7 show the electrically conductive adhesive applied continuously.

Although not shown, a wiring member 142 is positioned on the electrically conductive adhesive. Therefore, the width of the wiring member is narrower than that of the bus bar electrode.

As shown in FIGS. 6 and 7, first, in the temporary fixing step of the present invention, an electro-conductive adhesive (ECA) is placed between each of the bus bar electrodes and the wiring members to secure the bus bar electrodes and the wiring members. go and fix

Here, the electrically conductive adhesive is a mixture in which metal particles of micro, meso, or nano size are dispersed in an adhesive polymer such as epoxy, polyurethane, silicone, polyimide, phenol, or polyester. am. In this case, the metal particles may include silver, copper, aluminum, tin, or an alloy thereof.

The electrically conductive adhesive in the present invention is preferably located in the longitudinal direction of the bus bar electrode and wiring member. Because the electrically conductive adhesive in the present invention is generally low in light transmittance due to the constituent materials of the adhesive. Therefore, by placing the electrically conductive adhesive only between the wiring member and the bus bar electrode, it is possible to prevent the adhesive from deteriorating the effective surface area of the solar cell.

Meanwhile, the electrically conductive adhesive in the present invention can be pre-applied on the bus bar electrode and temporarily fix the bus bar electrode and the wiring member while aligning the wiring member. Alternatively, after being applied or coated on one side of the wiring member in advance, temporary fixation of the bus bar electrode and the wiring member may be performed simultaneously with alignment of the wiring member.

In FIGS. 6 and 7 , the bus bar electrode is shown as intersecting the finger electrode formed on the transparent electrode, but is not necessarily limited thereto. In the present invention, a plurality of bus bar electrodes may be positioned in one solar cell without a finger electrode, and a wiring member may be fixed in a direction crossing the finger electrode without a separate bus bar electrode.

In this way, the solar cells including the bus bar electrode and the temporarily fixed wiring member go through a stringing step (S 300), a lay-up step (S 400), and a lamination step (S' 500).

8 is a picture depicting a connection state between a bus bar electrode and a wiring member after lamination (S' 500) of the wiring member temporarily fixed by the electrically conductive adhesive of the present invention.

As shown in FIG. 8, the wiring material temporarily fixed to the bus bar electrode is electrically and/or mechanically coupled or fixed to the bus bar electrode after the low temperature lamination step (S' 500) of applying heat and pressure in the present invention. .

At this time, the interface between the bus bar electrode and the wiring material is clearly divided in the step before/after the lamination (S' 500).

First, in the interface after temporary fixation and before lamination, as shown in FIG. 6, only an electrically conductive adhesive and, in some cases, an empty space exist between the bus bar electrode and the wiring member.

Although FIG. 6 shows that the electrically conductive adhesive exists discontinuously in the longitudinal direction of the wiring member (same as the longitudinal direction of the bus bar), it is not necessarily limited thereto. As shown in FIG. 7, the electrically conductive adhesive may be continuously present or applied in the longitudinal direction of the wiring member. However, in this case, it is more preferable in terms of electrical conductivity for extracting charge carriers to the outside of the cell to adjust the amount or thickness of the electrically conductive adhesive.

If the electrically conductive adhesive is discontinuously present in the longitudinal direction of the wiring member, the ratio of the length of the electrically conductive adhesive layer is preferably 1 to 25% of the total length of the wiring member. If the length of the electrically conductive adhesive layer is less than 1%, the adhesive strength between the bus bar electrode and the wiring member is too small, and the wiring member temporarily fixed to the bus bar electrode may come off. Conversely, if the length of the electrically conductive adhesive layer is longer than 25%, if the thickness of the adhesive layer is not adjusted, the electrical conductivity between the bus bar electrode and the wiring material is lowered, resulting in a decrease in the charge carrier extraction efficiency, which reduces the photoelectric conversion efficiency of the solar cell module. likely to cause a decline.

On the other hand, the interface after the lamination step (S' 500) of applying heat and pressure, as shown in FIG. A eutectic mixture containing a metallic compound is newly formed.

The reason why the intermetallic compound is formed at the interface in the present invention is as follows.

First, the wiring material used in the solar cell is an alloy 142b in which Sn, Ag, Pb, etc. are mixed on the surface using copper (Cu) as a base 142a, as shown in FIG. 9, for electrical connection between solar cells. It is prepared by coating through various methods such as plating and dipping.

The coating material containing tin (Sn) may be composed of Sn, SnIn, SnBi, SnBiPb, SnPb, SnPbAg, SnCuAg, SnCu, etc. as non-limiting examples.

As a lead-containing material, antimony lead or hard lead containing about 1 to 10 wt % of antimony (Sb) in lead (Pb) is widely used as a cable covering material such as a wiring material.

In addition, the wiring material including these components is laminated by applying heat and pressure at a temperature of 150° C. or less through the low-temperature lamination step (S' 500).

The reason why the upper limit of the process temperature is limited to 150 ° C. in the low-temperature lamination (S' 500) in the present invention is as follows.

As described above, the solar cell of the present invention is a high-efficiency solar cell such as a perovskite solar cell or a heterojunction solar cell using amorphous silicon.

It has been reported that the high-efficiency solar cell of the present invention as described above, particularly the perovskite solar cell, accelerates the decomposition of the perovskite material due to moisture and thermal instability.

Perovskite materials are particularly vulnerable at high temperatures, and it has been reported that the CH ₃ NH ₃ PbI ₃ light absorbing layer is decomposed after 3 hours at 150° C. or higher even in a vacuum, resulting in cell deterioration. On the other hand, it is reported that the atmosphere is maintained stably in a vacuum or N2, O2 atmosphere even after exposure to 85 ° C for 24 hours. This means that the perovskite solar cell adopted in the present invention is very vulnerable to heat, and the low temperature lamination step (S' 500), which is adjusted so that the lamination step does not exceed 150 ° C., must be performed.

During the low-temperature lamination step (S'500) in the present invention, the bus bar electrode and the wiring material temporarily fixed in the present invention contain Ag, which is the main component of the bus bar electrode, and tin (Sn), which is a component of the alloy of the coating layer 142b of the wiring material, or Antimony (Sb) reacts with each other. Because the alloy of the coating layer 142b of the wiring material usually has a melting temperature of 150° C. or less, it is melted during the lamination step and reacts with Ag of the bus bar electrode.

Unlike Ag and Pb, which do not form intermetallic compounds, as shown in the Ag-Sb phase diagram of FIG. 10, Ag and Sb are intermetallic compounds having an orthorhombic crystal structure in the intermediate composition region. -metallic compound).

In addition, as shown in the Ag-Sn phase diagram of FIG. 11, the Ag and Sn alloy system also includes an inter-metallic compound of Ag ₃ Sn composition in the intermediate composition region.

Therefore, in the low-temperature lamination step (S'500) in the present invention, the Ag-Sb and Ag-Sn intermetallic compounds are included between the wiring material and the bus bar, and Sb or Sn, which is the main component of the wiring material and the bus bar electrode, is the metal. It forms a eutectic mixture mixed with liver compounds. In the present invention, bonding strength is basically higher than that of the electrically conductive adhesive, and since it essentially belongs to metal, there is an advantage in terms of electrical conductivity.

As a result, one embodiment of the present invention in which the bus bar electrode and the wiring member are temporarily fixed by discontinuously positioning the electrically conductive adhesive in the longitudinal direction of the wiring member (FIG. 6), between the bus bar electrode and the wiring member by lamination (S' 500) has an interfacial structure in which the electrically conductive adhesive and the eutectic mixture alternate (FIG. 7).

At this time, after the lamination step (S′ 500), the area ratio of the electrically conductive adhesive layer and the eutectic mixture in the interface layer (or the length ratio in the length direction of the wiring member) is (1 to 25): (75 to 99), respectively. it is desirable

If the ratio of the electrically conductive adhesive layer is less than 1% (or if the ratio of the eutectic mixture is greater than 99%), the adhesive strength between the bus bar electrode and the wiring material cannot be secured in the temporary fixing step, causing problems in temporarily fixing Occurs. On the other hand, if the ratio of the electrically conductive adhesive layer exceeds 25% (or if the ratio of the eutectic mixture is less than 75%), high electrical conductivity between the bus bar electrode and the wiring material cannot be secured after lamination, which prevents the collection of charge carriers. A problem arises.

Referring back to FIG. 9 , in the present invention, wiring members of various shapes may be used. As a specific example, a wiring member having a circular, elliptical or polygonal cross section may be used.

Among them, the circular or elliptical wiring member has a geometrically smaller contact area with the bus bar electrode than the polygonal wiring member. Due to this, there is a disadvantage in that the area or length ratio of the temporary fixing tape or the electrically conductive adhesive layer at the interface increases in the temporary fixing step. On the other hand, the circular or elliptical wiring member has the advantage of increasing the absorption efficiency of sunlight by promoting scattering or refraction of sunlight and lengthening the light path.

On the other hand, a polygonal (eg, square) wiring material has the advantage of minimizing the fraction at the interface of the temporary fixing tape or the electrically conductive adhesive layer because it can maximize the contact area with the bus bar electrode. On the other hand, the polygonal wiring member has the disadvantage of reducing the absorption efficiency of sunlight by reflecting it as it is without scattering or refracting a part of the incident sunlight due to its shape to the solar cell below.

12 is a cross-sectional view of a solar cell and module manufactured by the solar cell module manufacturing method of the present invention.

For convenience of explanation, FIG. 12 shows that the lower part of the solar cell does not have any components, but in reality, the second sealing material and the second protective member exist in the lower part as well as the upper part of the cell.

First, in the present invention, a tandem solar cell is illustrated as a cell of the solar cell module of the present invention for convenience of explanation, but is not necessarily limited thereto. As described above, the solar cell of the present invention is a single junction solar cell such as a crystalline silicon solar cell or a perovskite solar cell, or a tandem in which the single junction solar cell is bonded through an intermediate layer. All solar cells can be used.

The tandem solar cell in FIG. 12, which is an embodiment of the present invention, includes a perovskite solar cell 120 including an absorber layer having a relatively large band gap and a silicon solar cell including an absorber layer having a relatively small band gap ( 110) shows the structure of a two-terminal tandem solar cell 150 in which the interlayer 116 (hereinafter also referred to as "tunnel junction layer", "intermediate layer", or "inter-layer") is directly tunnel-junctioned. .

Accordingly, the light in the short wavelength region among the light incident to the tandem solar cell 150 is absorbed by the perovskite solar cell 120 disposed thereon to generate electric charge, and the perovskite solar cell 120 The penetrating light of the long wavelength region is absorbed by the crystalline silicon solar cell 110 disposed below to generate charge.

In addition, the crystalline silicon solar cell 110 disposed below absorbs and generates power in the long wavelength region, so that the threshold wavelength can be moved to the long wavelength side, and as a result, the wavelength band absorbed by the entire solar cell can be widened. There are tangible advantages.

In this case, an intermediate layer 116 may be inserted between the crystalline silicon solar cell 110 and the electron transport layer 123 as needed for charge transfer. In this case, the intermediate layer 116 is made of a transparent conductive oxide, a carbonaceous conductive material, Alternatively, it may be implemented using a metallic material. In addition, the bonding layer 116 may be doped with an n-type or p-type material.

Meanwhile, in a single junction solar cell, it is common to introduce a texture structure to the surface in order to reduce the reflectance of incident light on the surface and increase the path of light incident to the solar cell. Therefore, the crystalline silicon solar cell 110 in the tandem solar cell 150 according to the present invention may also form a texture on the surface (at least on the rear surface).

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

In the case of a heterojunction silicon solar cell, the crystalline silicon solar cell includes a crystalline silicon substrate 111 having a texture structure on a second surface, and intrinsic amorphous first surfaces respectively positioned on the first and second surfaces of the crystalline silicon substrate. a silicon layer (i-a-Si:H) 112 and a second side intrinsic amorphous silicon layer (i-a-Si:H) 113; a first conductivity type amorphous silicon layer 114 positioned on the first surface intrinsic amorphous silicon layer 112; and a second conductivity type amorphous silicon layer 115 positioned on the second surface i-type amorphous silicon layer 113.

At this time, as shown in FIG. 12, the first surface is the front surface of the crystalline silicon substrate on which the perovskite layer is formed, and the second surface may be a surface opposite to the first surface, but is necessarily limited thereto It is not.

For example, first, very thin intrinsic amorphous silicon (ia-Si:H) is formed as a passivation layer on the front and rear surfaces of an n-type crystalline silicon substrate, and p-type high-concentration amorphous silicon (pa-Si:H ) layer as the emitter layer 114 on the front and a high concentration amorphous silicon (n ⁺ -a-Si: H) layer on the back as the back surfacefield (hereinafter referred to as BSF) layer 115. can have

It is more preferable to use a hydrogenated intrinsic amorphous silicon layer (i-a-Si:H) as the intrinsic amorphous silicon layer in the present invention. This is because hydrogen enters amorphous silicon by a hydrogenation reaction and can reduce a dangling bond of amorphous silicon and a localized energy state within an energy band gap.

However, in the case of using the hydrogenated intrinsic amorphous silicon layer (i-a-Si:H), the subsequent process temperature is limited to 200°C or less, more preferably 150°C or less. This is because when the process temperature is higher than 150 ° C., hydrogen bonds inside the amorphous silicon are broken. Therefore, there is a restriction that subsequent processes, in particular, firing in a process for forming a grid electrode made of metal must also be performed at a low temperature.

Meanwhile, the silicon solar cell 110 in the present invention may be implemented as a homojunction crystalline silicon solar cell. Specifically, an impurity doped layer having a different conductivity type from that of the crystalline silicon substrate 111 is used as the emitter layer 114, and an impurity doped layer having the same conductivity type as the crystalline silicon substrate 111 is used as the back surface layer 115. By using the layer, a homojunction crystalline silicon solar cell 110 may be implemented.

A second electrode including a transparent electrode layer 117 and a grid electrode 118 is positioned on the second surface of the crystalline silicon substrate 111 .

In the case of a heterojunction silicon solar cell, as described above, in order to prevent hydrogen bond breakage within amorphous silicon, the process temperature of the second electrode (more specifically, the bus bar electrode 118) is is limited to 150° C. or less like the process temperature of the bus bar electrode 127). Accordingly, in this case, the second electrode may be formed before the first electrode, or the second electrode and the first electrode may be formed simultaneously.

The second electrode includes a transparent electrode layer 117 positioned on the back surface electric layer 115 . When a transparent conductive oxide such as ITO (Indium Tin Oxide), ZITO (Zinc Indium Tin Oxide), ZIO (Zinc Indium Oxide), ZTO (Zinc Tin Oxide) is used as a material for the transparent electrode layer, the transparent electrode layer 117 is formed through sputtering. may be deposited.

On the transparent electrode layer 117, a bus bar electrode 118 is positioned. Of course, the grid electrode 118 may be formed directly on the back surface layer 115 without forming the transparent electrode layer 117, but amorphous silicon is relatively difficult to collect carriers through a metal grid. ) Since the mobility is low, it is more preferable to form the transparent electrode layer 117.

Also, the bus bar electrode 118 may be disposed on the finger electrode positioned on the transparent electrode as described in FIG. 6 .

Unlike this, in the case of a homojunction silicon solar cell, the second electrode and the first electrode are not formed at the same time, but a process of forming the second electrode through a high-temperature firing process at 700° C. or higher and a first electrode paste that does not include a glass frit The process of forming the first electrode by low-temperature firing at 250° C. or less using may be performed in two ways.

After the crystalline silicon solar cell 110 is formed in this way, an intermediate layer 116 is formed thereon as necessary, and then a normal perovskite solar cell 110 is formed, so that a typical tandem aspect in the present invention The battery 150 may be implemented.

Next, the electron transport layer 123 located on the intermediate layer 116 serves to transfer the electrons photoelectrically converted in the perovskite layer 124 to other components (eg, conductive structures) in the solar cell. carry out

In this case, the electron transport layer 123 may be formed of an electron conductive organic material layer, an electron conductive inorganic material layer, or a layer including silicon (Si).

In addition, in the tandem solar cell of the present invention, electron transport characteristics between the electron transport layer 123 and the perovskite layer 124 are improved, and the electron transport layer 123 and the perovskite layer 124 are different from each other. A buffer layer 123' may be added to perform a function of minimizing defects at the interface due to differences in components and crystal structures. Furthermore, even if the electron transport layer 123 does not sufficiently perform the function of electron transport, the buffer layer 123' alone may perform the function of the electron transport layer to some extent.

Next, a typical tandem solar cell of the present invention includes a perovskite (absorption) layer.

The perovskite layer in the present invention includes a methylamminium (MA) component or a formamidinium (FA) component. More specifically, in the perovskite absorption layer represented by ABX ₃ , A includes one or more of two or more of a +1-valent C _1-20 alkyl group, an amine-substituted alkyl group, an organic amidinium, or an alkali metal, and B is Pb ²⁺ , Sn ^{2+ ,} Cu ²⁺ , Ca ^{2+ ,} Sr ²⁺ , Cd ^{2+ ,} Ni ^{2+ ,} Mn ^{2+ , Fe 2+ ,} Co ^{2+ ,} Pd ^{2+ ,} Ge ^{2+ , Yb 2+} , Eu ²⁺ includes one or more than one, and X includes one or more of F ^{- ,} Cl ^{- ,} Br ^- , I ^- .

Until now, it is known that the band gap of MA (Methylamminium) PbI ₃ used as a representative perovskite (absorption) layer is about (1.55-1.6) eV. On the other hand, it is known that the band gap of the FA system used as another perovskite absorption layer is smaller than that of the MA system. As an example, the band gap of FAPbI ₃ is about 1.45 eV. However, the addition of Br can increase the band gap of the FA-based perovskite absorber layer to a similar extent to that of the conventional MA-based perovskite absorber layer. When the band gap energy is included in a high range, the high band gap perovskite layer absorbs short wavelength light compared to conventional silicon solar cells, thereby reducing thermal loss caused by the difference between photon energy and band gap, thereby generating high voltage. can As a result, the efficiency of the solar cell is eventually increased.

Meanwhile, the perovskite phase constituting the perovskite layer is very vulnerable to heat. A perovskite layer represented by ABX ₃ is usually converted into ABX ₃ components by heat-treating an organic material of AX composition and an inorganic material of BX ₂ composition. Therefore, when the temperature and time are excessively high or long during the heat treatment for the conversion or the heat treatment in the subsequent process, thermal decomposition of the converted ABX ₃ may occur, resulting in a decrease in photoelectric conversion efficiency.

In the present invention, after forming the perovskite layer, a hole transport layer 125 may be additionally formed. The hole transport layer 125 serves to transfer holes photoelectrically converted in the perovskite layer 124 to other components in the solar cell.

In this case, the hole transport layer 125 may be formed of a layer including a hole conductive organic material layer, a hole conductive metal oxide, or silicon (Si).

A first electrode including a front transparent electrode layer 126 and a bus bar electrode 127 on the front transparent electrode layer 126 is positioned on the hole transport layer as needed. Of course, the bus bar electrode 127 may also be disposed on the finger electrode positioned on the transparent electrode as described in FIG. 6 .

At this time, the transparent electrode layer 126 is formed on the entire top surface of the perovskite solar cell 120, and serves to collect electric charges generated in the perovskite solar cell 120. The transparent electrode layer 126 may be implemented with various transparent conductive materials. That is, the same transparent conductive material as the transparent conductive material of the intermediate layer 116 may be used as the transparent conductive material.

At this time, the first electrode (specifically, the bus bar electrode 127) is disposed on the transparent electrode layer 126 and is disposed in a partial area of the transparent electrode layer 126.

The first electrode (specifically, the bus bar electrode 127) may be manufactured by selectively applying a first electrode paste that does not include a glass frit and then firing at a low temperature at a first temperature. Here, the first electrode paste may include metal particles and an organic material that is a binder for low-temperature firing, and the first electrode paste does not include a glass frit. In particular, the first temperature may be 150 °C or less, more specifically, 100 to 150 °C.

The solar cell manufactured as described above goes through the cell inspection step, temporary fixing step, layup step, lamination step, etc., which are the method of manufacturing the solar cell module of the present invention shown in FIG. It is completed with a solar cell module.

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

Claims (14)

an alignment step of aligning corresponding wiring members on respective electrodes of solar cells including a perovskite layer;
temporarily fixing the wiring members on the solar cell;
a string step of forming a string by arranging a plurality of solar cells to which the wiring member is temporarily fixed;
A lay-up step of arranging the string between sealing materials;
a low-temperature lamination step of bonding the arrayed strings at a temperature of 150° C. or less through a laminator and electrically bonding the wiring member to the solar cell;
including,
The temporary fixing step is a step of fixing with an electrically conductive adhesive positioned between each of the line members and electrodes aligned in a series,
The electrically conductive adhesive is discontinuously located in the longitudinal direction of the wiring members,
The electrode includes silver (Ag) and the wiring member includes tin (Sn) or antimony (Sb), and the lamination step forms a structure in which the electrically conductive adhesive and the eutectic mixture alternate between the electrode and the wiring member. To, a method for manufacturing a solar cell module. delete delete delete According to claim 1,
The ratio of the length of the electrically conductive adhesive in the longitudinal direction of the wiring members is 1 to 25%;
Method for manufacturing a solar cell module, characterized in that. delete A plurality of solar cells including a perovskite layer, a first electrode, and a second electrode;
A plurality of wiring members electrically connected to first electrodes and second electrodes of adjacent cells among the plurality of solar cells;
an electrically conductive adhesive layer present at an interface between the electrode and the wiring member;
including,
The ratio of the length of the electrically conductive adhesive layer in the longitudinal direction of the wiring members is 1 to 25%,
The first electrode and the second electrode include silver (Ag), the wiring member includes tin (Sn) or antimony (Sb), and between the first electrode and the second electrode and the wiring member, the electrical conductivity A solar cell module in which a structure in which an adhesive and a eutectic mixture are alternated is formed. delete delete delete delete According to claim 7,
a width of the electrically conductive adhesive layer is smaller than a width of the electrode;
A solar cell module characterized by a. According to claim 7,
The wiring members may include a metal core having a circular, elliptical, or polygonal cross section, and a solder layer coated on a surface of the metal core;
A solar cell module characterized by a. According to claim 7,
The solar cell is a perovskite solar cell or a tandem solar cell including a perovskite solar cell;
A solar cell module characterized by a.

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