KR102474476B1 - Solar cell module - Google Patents

Abstract

The present invention relates to a solar cell module.
A solar cell module according to an example of the present invention includes a semiconductor substrate, a first electrode extending in a first direction on the surface of the semiconductor substrate, and a second electrode having a polarity different from that of the first electrode on the surface of the semiconductor substrate. a plurality of solar cells; and connected to a first electrode of a first solar cell among a plurality of solar cells and a second electrode of a second solar cell adjacent to the first solar cell, and disposed in a second direction crossing the first direction to form a plurality of solar cells. A plurality of conductive wires electrically connected to each other, wherein each of the plurality of conductive wires is electrically connected to the first electrode of the first solar cell by a conductive adhesive at the intersection point with the first electrode of the first solar cell, and the intersection point An insulating adhesive covering the conductive adhesive is further provided on a portion of the conductive adhesive located on the side of the conductive wire.

Description

Solar cell module {SOLAR CELL MODULE}

The present invention relates to a solar cell module.

Recently, as the depletion of existing energy resources such as oil and coal is predicted, interest in alternative energy to replace them is increasing, and accordingly, solar cells that produce electrical energy from solar energy are attracting attention.

A typical solar cell includes a semiconductor unit forming a p-n junction by different conductivity types such as p-type and n-type, and electrodes respectively connected to the semiconductor units of different conductivity types.

When light is incident on such a solar cell, a plurality of electron-hole pairs are generated in the semiconductor part, and the generated electron-hole pairs are separated into charge electrons and holes, respectively, and the electrons move toward the n-type semiconductor part, and the holes are p Move towards the semiconductor part of the older brother. The moved electrons and holes are collected by different electrodes connected to the n-type semiconductor part and the p-type semiconductor part, respectively, and power is obtained by connecting these electrodes with wires.

Such solar cells may be connected to each other by interconnectors.

An object of the present invention is to provide a solar cell module.

A solar cell module according to an example of the present invention includes a semiconductor substrate, a first electrode extending in a first direction on the surface of the semiconductor substrate, and a second electrode having a polarity different from that of the first electrode on the surface of the semiconductor substrate. a plurality of solar cells; and connected to a first electrode of a first solar cell among a plurality of solar cells and a second electrode of a second solar cell adjacent to the first solar cell, and disposed in a second direction crossing the first direction to form a plurality of solar cells. A plurality of conductive wires electrically connected to each other, wherein each of the plurality of conductive wires is electrically connected to the first electrode of the first solar cell by a conductive adhesive at the intersection point with the first electrode of the first solar cell, and the intersection point An insulating adhesive covering the conductive adhesive is further provided on a portion of the conductive adhesive located on the side of the conductive wire.

Here, the insulating adhesive may be positioned at each intersection point and may not be located between intersection points.

In addition, the insulating adhesive may be provided to further cover the conductive wire in addition to a portion of the conductive adhesive positioned on the side of the conductive wire at the intersection.

Also, the formation area of the insulating adhesive may be wider than that of a portion of the conductive adhesive where the conductive adhesive is located on the side of the conductive wiring.

In addition, the solar cell module of the present invention includes a front transparent substrate disposed in front of a plurality of solar cells; a rear substrate disposed on a rear surface of the plurality of solar cells; and a filling sheet disposed between the front transparent substrate and the plurality of solar cells and between the rear substrate and the plurality of solar cells, wherein the filling sheet includes a first EVA (ethylene vinyl acetate), the first EVA The content ratio of vinyl acetate may be between 28wt% and 32wt%.

In addition, the insulating adhesive includes at least one material of polyethylene terephthalate (PET), polyimide (PI), polyolefin (PO), acrylic, silicone, epoxy, and second EVA, The vinyl acetate content ratio of the second EVA may be different from that of the first EVA.

Here, the content ratio of vinyl acetate in the second EVA may be less than 28wt% or greater than 32wt%.

For example, the insulating adhesive may be provided in the form of a base film and an insulating tape containing the adhesive on the surface of the base film.

Here, the base film includes any one of polyethylene terephthalate (PET), polyimide (PI), polyolefin (PO), and the second EVA, and the adhesive is one of acrylic, silicone, and epoxy may include either.

Also, as another example, the insulating adhesive may be formed by curing a curable polymer epoxy in a liquid state, or the insulating adhesive may be formed by heat-treating a second EVA in a highly viscous semi-liquid state.

In addition, each of the plurality of solar cells may include a first electrode on the front surface of the semiconductor substrate and a second electrode on the rear surface of the semiconductor substrate, and the plurality of conductive wires may be disposed to cross the first electrode of the first solar cell.

Here, each of the plurality of conductive wires may have a wire shape having a circular or elliptical cross section.

Alternatively, each of the plurality of solar cells includes first and second electrodes formed long in a first direction on the rear surface of the semiconductor substrate, and the plurality of conductive wires are formed on the first electrode of the first solar cell and the second electrode of the second solar cell. It may be connected crosswise to each of the second electrodes.

In this case, each of the plurality of conductive wires may have a ribbon shape having a cross section wider than the thickness.

The solar cell module according to the present invention may further improve the reliability of the module by further including an insulating adhesive on the conductive adhesive located at the intersection where the conductive wire and the electrode are electrically connected to each other.

1 schematically illustrates an exploded perspective view for explaining a solar cell module according to an example of the present invention.
FIG. 2 is a diagram for explaining an example of a connection structure of a plurality of solar cells shown in FIG. 1 .
3 is a diagram for explaining an example of the structure of each solar cell.
Figure 4 is an enlarged view of the K1 portion in Figure 2 (a).
5 is a diagram for explaining a corrosion phenomenon of the conductive adhesive 251.
Figure 6 (a) is an example showing a cross section along the line CS3-CS3 shown in Figure 4, Figure 6 (b) is a view for explaining another example of the insulating adhesive 270.
7 to 11 are views for explaining a solar cell module according to another example of the present invention.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

In the drawings, the thickness is shown enlarged to clearly express the various layers and regions. When a part such as a layer, film, region, or plate is said to be "on" another part, this includes not only the case where it is "directly on" the other part, but also the case where there is another part in between. Conversely, when a part is said to be "directly on" another part, it means that there is no other part in between. In addition, when a part is said to be formed “as a whole” on another part, it means that it is formed not only on the entire surface of the other part but also on some of the edges.

Hereinafter, the front side may be one side of the semiconductor substrate 110 on which direct light is incident, and the back side may be the opposite side of the semiconductor substrate 110 on which direct light is not incident or reflected light other than direct light is incident. have.

In addition, in the following description, the meaning that the lengths or widths of two different components are the same means that they are the same within an error range of 10%.

Then, a solar cell module according to an embodiment of the present invention will be described with reference to the accompanying drawings.

1 schematically illustrates an exploded perspective view for explaining a solar cell module according to an example of the present invention.

The solar cell module according to the present invention may include a front transparent substrate 40, a first filling sheet 30a, a plurality of solar cells, a second filling sheet 30b, and a back sheet 50.

The front transparent substrate 40 may be made of tempered glass having high transmittance and excellent damage prevention function. For example, the tempered glass may be low iron tempered glass having a low iron content.

Each of the plurality of solar cells functions to convert incident solar energy into electrical energy, and may include a semiconductor substrate 110 doped with impurities, various functional layers, and electrodes for this purpose.

The rear substrate 50 may protect the solar cells from the external environment by preventing moisture from penetrating from the rear surfaces of the solar cells.

The rear substrate 50 may be disposed on the rear surface of the front transparent substrate 40 to face the front transparent substrate 40 with solar cells disposed therebetween.

Such a rear substrate 50 may be in the form of a sheet or a glass substrate, and may have a multi-layer structure such as a layer that prevents penetration of moisture and oxygen, a layer that prevents chemical corrosion, and a layer that has insulating properties.

The filling sheet 30 may include a first filling sheet 30a positioned between the front transparent substrate 40 and the plurality of solar cells and a second filling sheet 30b positioned between the plurality of solar cells and the rear substrate. can

Such a filling sheet 30 may prevent corrosion due to penetration of moisture and protect the solar cell from impact.

The filling sheet 30 includes first ethylene vinyl acetate (EVA), and the content ratio of vinyl acetate in the first EVA may be between 28wt% and 32wt%. In this way, by setting the content ratio of vinyl acetate to be between 28wt% and 32wt%, the shock absorption function of the filling sheet can be further improved, and thus, the solar cell can be more effectively protected from external impact. can

In addition, such a filling sheet 30 is integrated with the solar cells by a lamination process while being disposed on the upper and lower portions of the solar cells, fills the space between the solar cells, and can be hardened through heat treatment. .

In this solar cell module, a structure of each of the plurality of solar cells and a connection structure in which the plurality of solar cells are connected will be described in detail as follows.

FIG. 2 is a diagram for explaining an example of a connection structure of a plurality of solar cells shown in FIG. 1, and FIG. 3 is a diagram for explaining an example of a structure of each solar cell.

Here, (a) of FIG. 2 shows a planar structure in which a plurality of solar cells are connected by a plurality of conductive wires 200, and (b) of FIG. 2 shows a line CS1-CS1 in FIG. FIG. 2(c) shows a cross section along the CS2-CS2 line in FIG. 2(a).

As shown in FIGS. 2 and 3 , each of the plurality of solar cells is provided with a semiconductor substrate 110 and a plurality of first electrodes 140 extending in a first direction (x) on the entire surface of the semiconductor substrate 110, , The second electrode 150 may be provided on the rear surface of the semiconductor substrate 110 .

The plurality of solar cells C1 and C2 are spaced apart and arranged in a second direction y intersecting the first direction x, and are adjacent to each other in the second direction y, as shown in FIG. 2 . It may include first and second solar cells C1 and C2.

The plurality of conductive wires 200 are disposed extending in the second direction (y), and are located on the first electrode 140 located on the front side of the first solar cell C1 and the rear side of the second solar cell C2. It can be connected to the second electrode 150 to be.

Accordingly, the first and second solar cells C1 and C2 adjacent to each other in the second direction y may form a string by the plurality of conductive wires 200 .

The conductive wire 200 may have a circular or elliptical cross section and may be a long wire shape.

In this case, the number N200 of the plurality of conductive wires 200 may be 6 to 33 based on one side of the solar cell. In addition, the width W200 of each of the plurality of conductive wires 200 may be between 250 um and 500 um.

For example, when the line width W200 of the conductive wire 200 is greater than or equal to 250 um and less than 300 um, the number N200 of the conductive wire 200 may be 15 to 33.

In addition, when the line width W200 of the conductive line 200 is greater than or equal to 300 um and less than 350 um, the number N200 of the conductive line 200 may be 10 to 15, and the line width W200 of the conductive line 200 may be When the thickness is 350 um or more and less than 400 um, the number of conductive wires 200 (N200) may be 8 to 10, and when the line width W200 of the conductive wires 200 is 400 um to 500 um, the number of conductive wires 200 (N200) may be 6 to 8.

As described above, by arranging the number (N200) of the conductive wires 200 differently according to the line width (W200) of the conductive wires 200, total shading covered by the conductive wires 200 on the light-receiving surface of the solar cell. ) It is possible to appropriately adjust the self-resistance of the conductive wire 200 without increasing the area, thereby minimizing the output reduced by the conductive wire 200 and further improving the output of the solar cell module. can make it

The relationship of the number according to the line width W200 of the conductive wires 200 described above is an optimized example, and the present invention is not necessarily limited thereto.

In addition, the pitch between the two adjacent conductive wires 200 may be between 4.75 mm and 25.13 mm in consideration of the line width W200 and the number of conductive wires 200 .

As shown in FIG. 3, each of the plurality of solar cells includes a semiconductor substrate 110, an emitter unit 120, an antireflection film 130, a first electrode 140, a back surface field , BSF), a back passivation film 180 and a second electrode 150 may be provided.

The semiconductor substrate 110 may have a first conductivity type, for example, a p-type or an n-type conductivity, and the semiconductor substrate 110 may be formed in any one of single-crystal silicon, poly-crystal silicon, and amorphous silicon. have. For example, the semiconductor substrate 110 may be formed of a crystalline silicon wafer.

Specifically, when the semiconductor substrate 110 has a p-type conductivity, the semiconductor substrate 110 may be doped with an impurity of a trivalent element such as boron 2, gallium, or indium.

However, when the semiconductor substrate 110 has n-type conductivity, impurities of a 5-valent element such as phosphorus (P), arsenic (As), and antimony (Sb) may be doped into the semiconductor substrate 110. .

The front surface of the semiconductor substrate 110 has a plurality of concavo-convex surfaces. For convenience, in FIG. 3, only the edge portion of the semiconductor substrate 110 is shown as a concave-convex surface, but substantially the entire front surface of the semiconductor substrate 110 has a concave-convex surface, so that the emitter portion located on the front surface of the semiconductor substrate 110 120 and the anti-reflection film 130 may also have concavo-convex surfaces.

As shown in FIG. 3, the emitter unit 120 is formed on the entire surface of the semiconductor substrate 110 of the first conductivity type and has a second conductivity type opposite to the first conductivity type, for example, n A region in which the semiconductor substrate 110 is doped with impurities of the type conductivity type, and may be positioned on a surface where light is incident, that is, inside the front surface of the semiconductor substrate 110 .

Accordingly, the emitter portion 120 of the second conductivity type forms a p-n junction with the portion of the first conductivity type of the semiconductor substrate 110 .

Light incident on the semiconductor substrate 110 is separated into electrons and holes so that electrons can move toward the n-type side and holes can move toward the p-type side. Accordingly, when the semiconductor substrate 110 is p-type and the emitter unit 120 is n-type, the separated holes may move toward the rear surface of the semiconductor substrate 110 and the separated electrons may move toward the emitter unit 120 .

Since the emitter unit 120 forms a p-n junction with the semiconductor substrate 110, that is, the first conductive portion of the semiconductor substrate 110, unlike the present embodiment, the semiconductor substrate 110 has an n-type conductivity. In this case, the emitter unit 120 may have a p-type conductivity. In this case, the separated electrons may move toward the rear surface of the semiconductor substrate 110 and the separated holes may move toward the emitter unit 120 .

When the emitter unit 120 has an n-type conductivity type, the emitter unit 120 may be formed by doping the semiconductor substrate 110 with impurities of a 5-valent element. Conversely, when it has a p-type conductivity type, It may be formed by doping the semiconductor substrate 110 with impurities of a trivalent element.

The anti-reflection film 130 is located on the incident surface of the semiconductor substrate 110, and as shown in FIGS. 3 and 5, when the emitter unit 120 is located on the incident surface of the semiconductor substrate 110, The anti-reflection layer 130 may be positioned on the emitter unit 120 .

Such an antireflection film 130 may be formed of a dielectric material, and for example, at least one of a hydrogenated silicon nitride film (SiNx:H), a hydrogenated silicon oxide film (SiOx:H), and a hydrogenated silicon nitride oxide film (SiNxOy:H). Any one may be formed of a plurality of layers.

By doing this, the passivation function of the antireflection film 130 can be further strengthened, and the photoelectric efficiency of the solar cell can be further improved.

As shown in FIG. 3 , the plurality of first electrodes 140 are located on the entire surface of the semiconductor substrate 110 and are spaced apart from each other on the entire surface of the semiconductor substrate 110, and each of the first electrodes 140 is disposed in a first direction (x). It can be extended and positioned.

At this time, the plurality of first electrodes 140 may be electrically connected to the emitter unit 120 by penetrating the anti-reflection film 130 .

Accordingly, the plurality of first electrodes 140 may be made of at least one conductive material such as silver (Ag) to collect charges, for example, electrons moving toward the emitter unit 120 .

As shown in FIG. 2 , a plurality of conductive wires 200 disposed long in the second direction (y) may be connected to the plurality of first electrodes by crossing each other.

The rear surface field region 172 may be located on a rear surface opposite to the front surface of the semiconductor substrate 110, and is doped with impurities of the same first conductivity type as the semiconductor substrate 110 at a higher concentration than the semiconductor substrate 110. , for example, may be a P+ region.

The back surface field portion 172 may be overlapped and connected to a pattern of the second electrode 150 to be described later and formed long in the first direction (x), but formed in the form of a plurality of lines spaced apart in the second direction (y). have. Therefore, the back surface field part 172 may be composed of a plurality of back surface field part lines 172 .

A potential barrier is formed due to the difference in impurity concentration between the first conductive region of the semiconductor substrate 110 and the back surface electric field region 172, which hinders the movement of electrons toward the back surface field region 172, which is the direction in which holes move. On the other hand, it is possible to facilitate the movement of holes toward the back surface field region 172 .

Therefore, the amount of charge lost due to recombination of electrons and holes on and around the rear surface of the semiconductor substrate 110 is reduced and the movement of desired charges (eg, holes) is accelerated to increase the amount of charge transfer to the second electrode 150. can increase

The back passivation film 180 may be formed to cover the entire rear surface of the semiconductor substrate 110 except for a portion where the second electrode 150 is formed, and may perform a passivation function and an insulation function for the rear surface of the semiconductor substrate 110. have. The back passivation layer 180 may include at least one layer of at least one of silicon nitride (SiNx), silicon oxide (SiOx), and silicon oxynitride (SiNxOy).

The second electrodes 150 are formed parallel to each other long in a first direction (x) on the back surface opposite to one surface of the semiconductor substrate 110, and extend in a second direction (y) intersecting the first direction (x). It can be formed spaced apart. However, this pattern of the second electrode 150 is an example, and is not necessarily limited thereto.

The second electrode 150 overlaps with and is electrically connected to the aforementioned back surface electric field part 172 and collects charges moving from the back surface field part 172 side, for example, holes.

At this time, since the second electrode 150 is in contact with the back surface electric field region 172 maintained at a higher impurity concentration than the semiconductor substrate 110, that is, the contact resistance between the back surface field region 172 and the second electrode 150. As this is reduced, charge transfer efficiency from the semiconductor substrate 110 to the second electrode 150 may be improved.

The conductive wire 200 is connected to the second electrode 150, and charges (eg, holes) collected on the second electrode 150 can be transferred to other adjacent solar cells through the conductive wire 200. .

The second electrode 150 may include a metal material having good conductivity, and may contain, for example, at least one conductive material such as silver (Ag).

The operation of the solar cell according to the present embodiment having such a structure is as follows.

When light is irradiated to the solar cell and incident on the emitter unit 120, which is a semiconductor unit, and the semiconductor substrate 110 through the emitter unit 120, electron-hole pairs are generated in the semiconductor unit by light energy. Such an electron-hole pair is separated from each other by a p-n junction between the semiconductor substrate 110 and the emitter unit 120, so electrons and holes are connected to the back surface of the emitter unit 120 having an n-type conductivity, for example. Each moves toward the stepfather 172. In this way, electrons moving toward the emitter part 120 are collected by the first electrode 140 and transferred to the conductive wire 200, and holes moving toward the back surface electric field part 172 are collected by the second electrode 150. It can be collected and transferred to the conductive wire 200 .

So far, the overall configuration of the solar cell module according to an example of the present invention, the connection relationship of a plurality of solar cells, and the structure of each solar cell have been described.

Hereinafter, a connection relationship between the first portion P1 of the first electrode 140 and the conductive wire 200 will be described in more detail.

FIG. 4 is an enlarged view of the K1 portion in FIG. 2 (a), FIG. 5 is a view for explaining the corrosion phenomenon of the conductive adhesive 251, and FIG. 6 (a) is the CS3- shown in FIG. It is an example showing a cross section along the CS3 line, and FIG. 6(b) is a diagram for explaining another example of the insulating adhesive 270.

As shown in FIG. 4 , each of the plurality of conductive wires 200 is electrically connected to each of the first electrodes by the conductive adhesive 251 at the intersection where each of the plurality of first electrodes intersects. It can be.

Here, the conductive adhesive 251 may be composed of, for example, at least one of SnPb, SnPbAc, SnAgCu, or SnAg.

In addition, an insulating adhesive 270 covering the conductive adhesive 251 may be further provided on a portion of the conductive adhesive 251 located at the intersection, which is located on the side of the conductive wire 200 . That is, the insulating adhesive 270 may be provided to cover the conductive adhesive 251 .

The insulating adhesive 270 may be positioned at each intersection point and may not be located between intersection points. Accordingly, the width of the insulating adhesive 270 in the second direction (y) may be smaller than the spacing between the first electrodes, and the width of the insulating adhesive 270 in the first direction (x) may be smaller than the spacing between the conductive wires 200. can be narrow

The insulating adhesive 270 is made of at least one of polyethylene terephthalate (PET), polyimide (PI), polyolefin (PO), acrylic, silicone, epoxy, and second EVA. can be formed, including

Here, the vinyl acetate content ratio of the second EVA may be different from that of the first EVA used as the filling sheet 30 . For example, the content ratio of vinyl acetate in the second EVA may be less than 28wt% or greater than 32wt%.

Here, the vinyl acetate content ratio of the second EVA is different from that of the first EVA, but the vinyl acetate content ratio is less than 28wt% or greater than 32wt%, so that the second EVA The moisture-proof properties of EVA can be further improved. However, when the content ratio of vinyl acetate is between 28wt% and 32wt%, EVA may not have desired moisture-proof properties.

Such an insulating adhesive 270 may be transparent or translucent, and has an excellent moisture-proof function, so even if the solar cell module is used for a long time in a field, it can suppress or prevent the phenomenon of corrosion of the conductive adhesive 251, Reliability of the solar cell module can be further improved.

That is, at the beginning of production of the solar cell module, the conductive adhesive 251 that physically and electrically connects the first electrode and the conductive wire 200 at the junction is strong and is not particularly problematic, but is used exposed to the external natural environment. Due to the use characteristics of the solar cell module, when used outside for a long period of time, moisture 400 is present around the conductive adhesive 251 as shown in FIG. Moisture condensation may occur.

Accordingly, as shown in (b) of FIG. 5, a chemical reaction occurs between the conductive adhesive 251 and the moisture 400, and metal ions constituting the conductive adhesive 251, for example, tin ions (Sn2+) or Galvanic corrosion in which lead ions (Pb 2+ ) escape into the condensed moisture 400 may begin.

Accordingly, as shown in (c) of FIG. 5, while the galvanic corrosion continues, the conductive adhesive 251 is dissolved and eroded in the direction of the arrow, and as shown in (d) of FIG. 5, the conductive adhesive 251 Crevice generation may be created.

Eventually, such galvanic corrosion may cause defects in the solar cell module and reduce reliability.

However, as shown in FIG. 4 of the present invention, when the insulating adhesive 270 covering the conductive adhesive 251 located at the intersection is provided, even if the moisture 400 is condensed around the conductive adhesive 251, the conductive adhesive 251 is conductive. Since the insulating adhesive 270 having a moisture-proof function blocks between the adhesive 251 and the condensed moisture 400, a phenomenon in which a chemical reaction occurs between the conductive adhesive 251 and the condensed moisture 400 is suppressed or prevented. Therefore, it is possible to prevent or suppress galvanic corrosion as described above.

Accordingly, long-term reliability of the solar cell module can be further improved.

As such, the insulating adhesive 270 covering the conductive adhesive 251 positioned at the intersection may be formed in various shapes and materials.

For example, as shown in (a) of FIG. 6 , the formation area of the insulating adhesive 270 is greater than the area of a portion of the conductive adhesive 251 where the conductive adhesive 251 is located on the side of the conductive wire 200. can be made wider. Accordingly, the blocking effect between the conductive adhesive 251 and the condensed moisture 400 can be further increased.

In addition, in order to more effectively prevent galvanic corrosion, the insulating adhesive 270 is provided to further cover the conductive wiring 200 in addition to a portion of the conductive adhesive 251 located on the side of the conductive wiring 200 at the intersection. It is also possible.

That is, as shown in (b) of FIG. 6, not only the part of the conductive adhesive 251 where the insulating adhesive 270 is located on the side of the conductive wire 200 at the intersection, but also the conductive adhesive 251 is not located. It is also possible to completely cover the upper part of the conductive wiring 200 that is not covered.

As shown in (b) of FIG. 6 , when the insulating adhesive 270 completely covers not only the conductive adhesive 251 at the intersection but also the upper portion of the conductive wire 200 located at the intersection, the insulating adhesive 270 is moisture-proof. By making the properties more robust, the aforementioned galvanic corrosion can be prevented more reliably.

The insulating adhesive 270 may be formed in various ways.

For example, the insulating adhesive 270 is formed by being adhered to the conductive adhesive 251 located at the junction in the form of an insulating tape having a case-(1) base film and an adhesive, or in a liquid form at the junction of the case-(2). After being applied on the conductive adhesive 251 located at , it is hardened by heat or UV (ultra violet) irradiation, or case-(3) in the form of a highly viscous semi-liquid paste like toothpaste, the conductive adhesive 251 located at the intersection After being applied thereon, it may be cured and formed by a lamination process.

For example, when the case-(1) insulating adhesive 270 is provided in the form of an insulating tape, as shown in (a) of FIG. 6, the insulating adhesive 270 may include a base film and an adhesive on the surface of the base film. , and the adhesive may be adhered to the surface of the conductive adhesive 251 located at the intersection.

Here, the base film may contain any one of polyethylene terephthalate (PET), polyimide (PI), polyolefin (PO), and second EVA, and the adhesive may be acrylic, Any one of silicone and epoxy may be included and used.

Here, the content ratio of vinyl acetate in the second EVA may be less than 28wt% or greater than 32wt%.

As in Case-(2), when the insulating adhesive 270 is applied in a liquid state and cured, the insulating adhesive 270 may include a curable polymer epoxy.

In this way, when the curable polymer epoxy is formed as the insulating adhesive 270, the once cured insulating adhesive 270 may not be affected by heat treatment in a subsequent lamination process.

Next, as in Case-(3), when the insulating adhesive 270 is formed in a highly viscous semi-liquid state, the content ratio of vinyl acetate in the insulating adhesive 270 is less than 28wt% or 32wt%. An excess second EVA may be used, and the second EVA may be heat treated and cured during the lamination process.

For reference, here, the conductive wire 200 may be in the form of a wire having a circular or elliptical cross section, and may include a core 201 made of a conductive material such as silver or copper, and coated with a surface of the core 201 and containing tin. A coating layer 202 may be included.

Here, the coating layer 202 may be composed of, for example, at least one of SnPb, SnPbAc, SnAgCu, or SnAg.

Here, the diameter of the core 201 may be between 200 μm and 310 μm, and the thickness of the coating layer 202 may be between 10 μm and 20 μm.

So far, the case where the insulating adhesive 270 of the present invention is applied to a conventional solar cell module in which the first electrode 150 is formed on the front surface of the semiconductor substrate 110 and the second electrode 150 on the rear surface has been described as an example. The insulating adhesive 270 may be equally applied to a back contact solar cell module in which both first and second electrodes are positioned on the back surface of the semiconductor substrate 110 .

7 to 11 are diagrams for explaining a solar cell module according to another example of the present invention, FIG. 7 is a front view of the solar cell module according to another example of the present invention, and FIG. It shows the rear surface of a solar cell module according to an example, and FIG. 9 is a partial perspective view for explaining an example of a structure of a solar cell of a solar cell module according to another example of the present invention, and FIG. It is an enlarged view, and FIG. 11 shows a cross section taken along line CS4-CS4 in FIG. 10 .

As shown in FIGS. 7 to 8 , in the solar cell module according to another example of the present invention, the first and second solar cells each have first and second electrodes on the rear surface of the semiconductor substrate, and a plurality of conductive wires 200 ) may be connected to the first and second electrodes on the rear surface of the semiconductor substrate 110 provided in each of the first and second solar cells C1 and C2.

Here, the first and second solar cells C1 and C2 may be arranged spaced apart in the first direction (x), and as shown in FIG. 8 , each of the first and second solar cells C1 and C2 is at least The semiconductor substrate 110 and a plurality of first electrodes 140' formed on the rear surface of the semiconductor substrate 110 spaced apart from each other and extending in a second direction (y) intersecting the first direction (x), and a plurality of first electrodes 140' and a plurality of second electrodes 140'. Two electrodes 150' may be provided.

In addition, the plurality of conductive wires 200 are disposed extending in the first direction (x), which is the arrangement direction of the first and second solar cells C1 and C2, and are disposed on the first and second solar cells C1 and C2, respectively. can be connected.

Here, the plurality of conductive wires may include first and second conductive wires, and the first conductive wires may be connected to the first electrode of each solar cell, and the second conductive wire may be connected to the second electrode of each solar cell.

For example, the plurality of first and second conductive wires 200 intersect and overlap the plurality of first electrodes 140' provided in the first and second solar cells C1 and C2, respectively, to be connected. It may include a plurality of second conductive wires 220 crossing and overlapping the conductive wires 210 and the plurality of second electrodes 150'.

The first and second conductive wires 200 are formed of a conductive metal material, and include a conductive core containing any one of gold (Au), silver (Ag), copper (Cu), or aluminum (Al), and a core (CR) It coats the surface of and may include a conductive coating layer containing tin (Sn) or an alloy containing tin (Sn).

As a preferred example, the core may be formed of copper (Cu), and the coating layer may be formed of SnBiAg, which is an alloy containing tin (Sn).

Among both ends of the first conductive wire 210, one end connected to the interconnector 300 may protrude out of one side of the semiconductor substrate 110, and among both ends of the second conductive wire 220, the interconnector 300 ) and one end connected to may protrude out of the other side surface of the semiconductor substrate 110 .

Therefore, one end of the first conductive wire 210 and one end of the second conductive wire 220 may protrude out of the projection area of the semiconductor substrate, respectively, and the other end of the first conductive wire 210 and the second conductive wire 220 may protrude out of the projection area of the semiconductor substrate. ) may be located within the projection area of the semiconductor substrate.

Here, the plurality of first and second conductive wires 200 may have a shape of a conductive wire having a circular cross section or a shape of a ribbon having a width greater than a thickness.

Here, the line width of each of the first and second conductive wires 200 may be formed between 0.5 mm and 2.5 mm in consideration of minimizing manufacturing cost while keeping the line resistance of the conductive wires sufficiently low. The distance between 210 and the second conductive wire 220 may be between 4 mm and 6.5 mm in consideration of the total number of first and second conductive wires 200 so as not to damage the short-circuit current of the solar cell module. .

As such, the number of first and second conductive wires 200 respectively connected to one solar cell may be 10 to 20. Accordingly, the total number of first and second conductive wires 200 connected to one solar cell may be 20 to 40.

One end of each of the plurality of first and second conductive wires 200 may be connected to the interconnector 300 to connect a plurality of solar cells in series to form a string.

More specifically, the interconnector 300 may be located between the first solar cell C1 and the second solar cell C2 and extend long in the second direction y.

Here, as shown in FIGS. 7 and 8 , when the solar cell is viewed from a plane, the interconnector 300 includes the semiconductor substrate 110 of the first solar cell C1 and the semiconductor of the second solar cell C2. It may be disposed spaced apart from the substrate 110 .

In addition, one end of the first conductive wire 210 connected to the first electrode 140' of the first solar cell C1 and the second electrode of the second solar cell C2 ( 150'), one end of the second conductive line 220 is connected in common, so that the first and second solar cells C1 and C2 may be serially connected to each other in the first direction (x).

More specifically, in a state in which the first and second solar cells C1 and C2 are arranged in the first direction (x), the first and second solar cells C1 and C2 are connected to the first and second conductive wires 200 One string that is extended in the first direction (x) by the interconnector 300 and connected in series may be formed.

Here, as an example, one end of each of the first and second conductive wires 200 may be overlapped with the interconnector 300 and adhered to the interconnector 300 through the conductive adhesive 251 .

Here, the conductive adhesive 251 bonding the first and second conductive wires 200 and the interconnector 300 to each other may be formed of a metal material including tin (Sn) or an alloy containing tin (Sn). .

More specifically, the conductive adhesive 251 is (1) formed in the form of a solder paste containing tin (Sn) or an alloy containing tin (Sn), (2) tin (Sn) or tin (Sn) in epoxy. It may be formed in the form of an epoxy solder paste or conductive paste containing an alloy containing tin (Sn).

Since the solar cell module having such a structure includes a separate interconnector 300, a connection failure occurs between the first and second conductive wires 200 and the first and second electrodes 200 among a plurality of solar cells. When there is a battery, the connection between the interconnector 300 and the plurality of first and second conductive wires 200 is released, so that only the corresponding solar cell can be more easily replaced.

Until now, in the solar cell module according to the present invention, the first and second conductive wires 200 are connected to the rear surfaces of each of the first and second solar cells C1 and C2 adjacent to each other, and the first and second solar cells ( A structure in which C1 and C2) are serially connected to the interconnector 300 has been described.

Hereinafter, a specific structure of a solar cell applicable to the first and second solar cells C1 and C2 will be described.

9 is a diagram for explaining an example of a solar cell applied to a solar cell module according to another example of the present invention, and is a partial perspective view showing an example of a back contact solar cell.

As shown in FIG. 9 , an example of a solar cell according to the present invention includes an antireflection film 130, a semiconductor substrate 110, a tunnel layer 180, a first semiconductor unit 121, and a second semiconductor unit 172. , an intrinsic semiconductor unit 150, a passivation layer 190, a plurality of first electrodes 140', and a plurality of second electrodes 150'.

Here, the anti-reflection film 130, the tunnel layer 180, and the passivation layer 190 may be omitted, but when provided, the efficiency of the solar cell is further improved, so the case where they are provided will be described as an example below.

The semiconductor substrate 110 may be formed of at least one of monocrystalline silicon and polycrystalline silicon doped with impurities of the first conductivity type or the second conductivity type. For example, the semiconductor substrate 110 may be formed of a single crystal silicon wafer.

The antireflection film 130 is positioned on the front surface of the semiconductor substrate 110 to minimize reflection of light incident on the front surface of the semiconductor substrate 110 from the outside, and is made of aluminum oxide (AlOx), silicon nitride (SiNx), silicon It may be formed of at least one of an oxide layer (SiOx) and a silicon oxynitride layer (SiOxNy).

The tunnel layer 180 is disposed in direct contact with the entire rear surface of the semiconductor substrate 110 and may include a dielectric material. Accordingly, the tunnel layer 180 may pass carriers generated in the semiconductor substrate 110 as shown in FIG. 9 .

Such a tunnel layer 180 may pass carriers generated in the semiconductor substrate 110 and perform a passivation function for the back surface of the semiconductor substrate 110 .

As shown in FIG. 9 , the first semiconductor unit 121 may be disposed on the back surface of the semiconductor substrate 110 and, for example, directly contact a portion of the rear surface of the tunnel layer 180 .

In addition, such a first semiconductor unit 121 is disposed on the rear surface of the semiconductor substrate 110 long in the second direction (y), and is formed of a polycrystalline silicon material having a first conductivity type opposite to the second conductivity type. can

Here, the first semiconductor portion 121 may be doped with impurities of the first conductivity type, and when the impurities contained in the semiconductor substrate 110 are impurities of the second conductivity type, the first semiconductor portion 121 may tunnel A p-n junction may be formed with the semiconductor substrate 110 with the layer 180 therebetween.

Since each first semiconductor unit 121 forms a p-n junction with the semiconductor substrate 110, the first semiconductor unit 121 may have a p-type conductivity, and the plurality of first semiconductor units 121 may have a p-n junction. In the case of a positive conductivity type, the first semiconductor portion 121 may be doped with impurities of a trivalent element.

The second semiconductor unit 172 is disposed on the rear surface of the semiconductor substrate 110 extending long in the second direction (y) parallel to the first semiconductor unit 121, and for example, among the rear surfaces of the tunnel layer 180, the second semiconductor unit 172 is disposed. It may be formed by directly contacting a partial area spaced apart from each of the first semiconductor units 121 .

The second semiconductor unit 172 may be formed of a polycrystalline silicon material doped with impurities of the second conductivity type at a higher concentration than the semiconductor substrate 110 . Therefore, for example, when the semiconductor substrate 110 is doped with an n-type impurity that is a second conductivity type, the plurality of second semiconductor portions 172 may be n+ impurity regions.

The second semiconductor unit 172 hinders the movement of holes toward the second semiconductor unit 172, which is the direction in which electrons move, by a potential barrier caused by a difference in impurity concentration between the semiconductor substrate 110 and the second semiconductor unit 172. On the other hand, it is possible to facilitate the movement of carriers (eg, electrons) toward the second semiconductor unit 172 .

Therefore, the amount of electric charge lost through recombination of electrons and holes in the second semiconductor unit 172 and its vicinity or in the first and second electrodes 200 is reduced and electron movement is accelerated so that electrons into the second semiconductor unit 172 Movement can be increased.

In FIG. 9 so far, while explaining the case where the semiconductor substrate 110 is an impurity of the second conductivity type as an example, the first semiconductor part 121 serves as an emitter part, and the second semiconductor part 172 serves as a back surface. The case of acting as a former stepfather has been described as an example.

However, differently from this, when the semiconductor substrate 110 contains impurities of the first conductivity type, the first semiconductor portion 121 serves as a back surface electric field region and the second semiconductor portion 172 serves as an emitter region. You can also do

In addition, in FIG. 9 herein, a case in which the first semiconductor unit 121 and the second semiconductor unit 172 are formed of a polycrystalline silicon material on the rear surface of the tunnel layer 180 has been described as an example.

However, differently from this, when the tunnel layer 180 is omitted, the first semiconductor portion 121 and the second semiconductor portion 172 may be doped by diffusion of impurities into the back surface of the semiconductor substrate 110, such as In this case, the first semiconductor unit 121 and the second semiconductor unit 172 may be formed of the same single crystal silicon material as the semiconductor substrate 110 .

As shown in FIG. 9 , the intrinsic semiconductor unit 150 may be formed on the rear surface of the tunnel layer 180 exposed between the first semiconductor unit 121 and the second semiconductor unit 172, and such an intrinsic semiconductor unit 150 may have Unlike the first semiconductor unit 121 and the second semiconductor unit 172 , the semiconductor unit 150 may be formed of an intrinsic polycrystalline silicon layer that is not doped with impurities of the first conductivity type or impurities of the second conductivity type.

In addition, as shown in FIG. 9 , both side surfaces of the intrinsic semiconductor unit 150 may have a structure in direct contact with the side surfaces of the first semiconductor unit 121 and the side surfaces of the second semiconductor unit 172 .

The passivation layer 190 is a defect due to a dangling bond formed on the back surface of the polycrystalline silicon layer formed on the first semiconductor unit 121, the second semiconductor unit 172, and the intrinsic semiconductor unit 150. By removing the carriers, carriers generated from the semiconductor substrate 110 may play a role of preventing disappearance due to recombination by dangling bonds.

As shown in FIG. 8 , the plurality of first electrodes 140 ′ may be connected to the first semiconductor unit 121 and extended in the second direction y. As such, the first electrode 140 ′ may collect carriers, for example, holes that have moved toward the first semiconductor unit 121 .

The plurality of second electrodes 150' may be connected to the second semiconductor unit 172 and extended in the second direction (y) parallel to the first electrode 140'. As such, the second electrode 150 ′ may collect carriers, for example, electrons that have moved toward the second semiconductor unit 172 .

The first electrode 140' and the second electrode 150' are formed long in the second direction (y) and may be spaced apart in the first direction (x). In addition, as shown in FIG. 8 , the first electrode 140' and the second electrode 150' may be alternately disposed in the first direction (x).

In the solar cell according to the present invention manufactured with such a structure, the holes collected through the first electrode 140' and the electrons collected through the second electrode 150' are converted into power of the external device through an external circuit device. can be used

The solar cell applied to the solar cell module according to the present invention is not necessarily limited to FIGS. 9 and 7 , except that the first and second electrodes 200 provided in the solar cell are formed only on the back surface of the semiconductor substrate 110. and other components can be changed at any time.

As such, each of the solar cells applied to the solar cell module according to another example of the present invention, as shown in FIG. 140' and 150'), and the plurality of first and second conductive wires 210 and 220 are the first electrode 140' of the first solar cell C1 and the second electrode 140' of the second solar cell C2. Each of the electrodes 150' may be connected crosswise.

More specifically, as shown in FIG. 10 , in each of the plurality of solar cells C1 and C2, the first conductive wire 210 is a conductive adhesive 251 made of a conductive material at an intersection where the first electrode 140' intersects. ), and may be insulated from the second electrode 150' by an insulating layer 252 made of an insulating material at an intersection where it intersects the second electrode 150'.

In addition, a conductive adhesive 251 is applied to the second electrode 150' at the intersection where the second conductive wires 220 and 220 intersect the second electrode 150' in each of the plurality of solar cells C1 and C2. It is connected through and can be insulated from the first electrode 140' by the insulating layer 252 at the intersection where the first electrode 140' crosses.

Here, the conductive adhesive 251 may be formed of a conductive metal material, and may be formed in any one form of solder paste, epoxy solder paste, or conductive paste. can

Here, the solder paste layer may be formed of tin (Sn) or an alloy containing tin (Sn), and the epoxy solder paste layer may be formed of tin (Sn) or an alloy containing tin (Sn) in epoxy.

Here, the insulating layer 252 may be any insulating material, and for example, any one of epoxy-based, polyimide, polyethylene, acryl-based, and silicon-based insulating materials may be used.

Meanwhile, among the intersections of the first and second electrodes 140' and 150' and the first and second conductive wires 210 and 220, as shown in FIGS. 10 and 11(a), a conductive adhesive 251 Among the conductive adhesives 251 located at the intersection between the first electrode 140' and the first conductive wire 210 and the intersection between the second electrode 150' and the second conductive wire 220 connected through An insulating adhesive 270 covering the conductive adhesive 251 may be further provided on a portion located on a side surface of the conductive wire 200 .

In addition, as shown in FIG. 10, the insulating adhesive 270 is applied at the intersection between the first and second electrodes 140' and 150' having the same polarity and the first and second conductive wires 210 and 220, respectively. It is located at each intersection point, and may not be located between each intersection point.

In addition, as another example, as shown in FIG. It may be provided to cover more.

In addition, the formation area of the insulating adhesive 270 may be larger than that of a portion of the conductive adhesive 251 positioned on the side surface of the conductive wire 200 .

Although FIG. 11 illustrates an example in which the insulating adhesive 270 is formed at the intersection between the first electrode 140' and the first conductive wire 210, the second electrode 150' and the second conductive wire 220 ), the insulating adhesive 270 may be similarly formed on the conductive adhesive 251 located at the intersection between

The material of the insulating adhesive 270 may be the same as described above.

As described above, the solar cell module according to the present invention further includes the insulating adhesive 270 on the conductive adhesive 251 located at the intersection, thereby further improving the reliability of the solar cell module.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims are also included in the scope of the present invention. that fall within the scope of the right.

Claims (15)

a plurality of solar cells each including a semiconductor substrate, a first electrode extending along a first direction on a surface of the semiconductor substrate, and a second electrode having a polarity different from that of the first electrode on a surface of the semiconductor substrate;
a front transparent substrate disposed on front surfaces of the plurality of solar cells;
a rear substrate disposed on a rear surface of the plurality of solar cells;
A first EVA disposed between the front transparent substrate and the plurality of solar cells and between the rear substrate and the plurality of solar cells, and having a content ratio of vinyl acetate between 28wt% and 32wt% (EVA, ethylene A filling sheet containing vinyl acetate);
Connected to a first electrode of a first solar cell among the plurality of solar cells and a second electrode of a second solar cell adjacent to the first solar cell, and arranged in a second direction crossing the first direction, a plurality of conductive wires electrically connecting the solar cells;
It is located between the plurality of conductive wires and the first electrode of the first solar cell at the intersection of the plurality of conductive wires and the first electrode of the first solar cell, and is located between a part of the outer surface of the plurality of conductive wires and the first electrode of the first solar cell. a conductive adhesive electrically connecting the plurality of conductive wires and the first electrode of the first solar cell by contacting the first electrode of one solar cell; and
An insulating adhesive that is located at each of the intersection points, is not located between the intersection points, and covers the entirety of the outer surfaces of the plurality of conductive wires that are not in contact with the conductive adhesive and the outer surfaces of the conductive adhesive.
including,
The insulating adhesive is provided in the form of an insulating tape including a base film and an adhesive formed on a surface of the base film,
In the base film, the content ratio of polyethylene terephthalate (PET), polyimide (PI), acrylic, silicone, epoxy, and vinyl acetate is different from the content ratio of vinyl acetate of the first EVA. 2 contains at least one material of EVA,
The solar cell module wherein the adhesive includes any one of acrylic, silicone, and epoxy. delete delete According to claim 1,
The solar cell module of claim 1 , wherein a formation area of the insulating adhesive is larger than an area of a portion of the conductive adhesive where the conductive adhesive is located on a side surface of the conductive wiring. delete delete According to claim 1 or 4,
The solar cell module wherein the content ratio of vinyl acetate in the second EVA is less than 28wt% or greater than 32wt%. delete delete delete delete According to claim 7,
Each of the plurality of solar cells includes the first electrode on the front surface of the semiconductor substrate and the second electrode on the rear surface of the semiconductor substrate,
The plurality of conductive wires are arranged to cross the first electrode of the first solar cell. According to claim 7,
The solar cell module of claim 1 , wherein each of the plurality of conductive wires has a wire shape having a circular or elliptical cross section. According to claim 7,
Each of the plurality of solar cells includes the first and second electrodes formed long in the first direction on the back surface of the semiconductor substrate,
The plurality of conductive wires are cross-connected to the first electrode of the first solar cell and the second electrode of the second solar cell, respectively. According to claim 14,
The solar cell module of claim 1 , wherein each of the plurality of conductive wires has a ribbon shape having a cross section wider than a thickness.

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