KR101743717B1 - Solar cell module and manufacturing method of a wire for solar cell module - Google Patents

Abstract

The present invention relates to a solar cell module and a method of manufacturing a wiring used therein.
An example of a solar cell module according to the present invention includes a plurality of wirings connected to electrodes provided in each of a plurality of solar cells and a plurality of solar cells through a conductive adhesive agent, A plurality of irregularities are provided on the surface of the second portion opposite to the first portion with respect to the center of the wiring.
In addition, a method of manufacturing a wiring used in a solar cell module includes a rolling step of forming a plurality of projections and depressions in a first portion and a second portion in a solar cell wiring core, and a coating step of forming a coating layer on a surface of a core .

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a solar cell module,

The present invention relates to a solar cell module and a method of manufacturing a wiring used therein.

Recently, as energy resources such as oil and coal are expected to be depleted, interest in alternative energy to replace them is increasing, and solar cells that produce electric energy from solar energy are attracting attention.

Typical solar cells have a semiconductor portion that forms a p-n junction by different conductive types, such as p-type and n-type, and electrodes connected to semiconductor portions of different conductivity types, respectively.

When light is incident on such a solar cell, a plurality of electron-hole pairs are generated in the semiconductor portion, and the generated electron-hole pairs are separated into electrons and holes, respectively, so that the electrons move toward the n- Type semiconductor portion. The transferred electrons and holes are collected by different electrodes connected to the n-type semiconductor portion and the p-type semiconductor portion, respectively, and electric power is obtained by connecting these electrodes with electric wires.

Such solar cells can be electrically connected to each other by wiring.

According to the conventional patent publication No. US 2006/0272844, an interconnection line connecting a plurality of solar cells in series has a structure in which irregularities are formed on a front surface or a front surface or a front surface of a core in which a whole surface or a cross- The core surface may be coated with a thick solder layer in some cases.

However, in the case where the solder layer is thickly coated with the irregularities formed on the entire surface of the round core, if the irregularities of the core do not protrude to the surface of the solder layer, there is no unevenness on the outer surface of the solder layer, .

In addition, when the concave and convex portions are formed on the front surface and the front and rear surfaces of the rectangular core and the solder layer is formed thick and no irregularities are formed on the outer surface of the solder layer, the surface of the solder layer is flat, It is difficult to provide an optical path for re-entering into the solar cell module, and the shading area is relatively increased at the front surface of the solar cell in which the light is incident due to the rectangular core.

It is an object of the present invention to provide a solar cell module and a method of manufacturing a wiring used therein.

An example of a solar cell module according to the present invention includes a plurality of solar cells each having an electrode formed on a surface of a semiconductor substrate and a semiconductor substrate; And a plurality of wires connected to electrodes provided in each of the plurality of solar cells via a conductive adhesive in order to electrically connect a plurality of adjacent solar cells among the plurality of solar cells, A plurality of irregularities are provided on the surface of the first part to be connected and a plurality of irregularities are provided on the surface of the second part opposite to the first part with respect to the center of the wiring.

Here, the cross section of the wiring has a circular or oval shape as a whole, and irregularities may not be formed on the surface between the first and second portions in the wiring.

In addition, the wiring includes a coating layer coating the surface of the core and the core, and the core is formed of any one of copper (cu), silver (Ag), gold (Au), and aluminum ) Or tin (Sn), and the thickness of the coating layer may be smaller than the width or height of the concavities and convexities formed in the first and second portions.

Here, the maximum diameter of the core is between 200 [mu] m and 500 [mu] m, and the thickness of the coating layer may be between 1 [mu] m and 5 [mu] m.

In addition, the width or height of each of the plurality of irregularities formed in the first and second portions is larger than the thickness of the coating layer, the width of each of the plurality of irregularities formed in the first and second portions is between 20um and 25um, The height of each of the plurality of concavities and convexities formed on the substrate may be between 20 um and 30 um.

The width and height of the irregularities located at the outermost portions of the first and second portions in each of the first and second portions may be smaller than the width and height of the irregularities located in the middle portions of the first and second portions.

Each of the plurality of irregularities formed in the first and second portions may have a groove shape extending long in the longitudinal direction, the width direction, or the oblique direction of the wiring, or may have a pyramid shape.

Here, the width of the first and second portions in which a plurality of irregularities are formed in the wiring may be between 100 μm and 150 μm.

The width of the conductive adhesive may be larger than the width of the first portion or second portion connected to the conductive adhesive and may be smaller than the maximum line width of the wiring. As an example, the width of the conductive adhesive may be between 320 and 380 um.

The conductive adhesive may be in the form of a solder paste containing tin (Sn) or may be in the form of a conductive adhesive paste in which a plurality of conductive particles are distributed in the adhesive resin.

For example, when the conductive adhesive contains a plurality of conductive particles distributed in the adhesive resin, the adhesive resin is formed of at least one of an epoxy-based resin, a silicone-based resin, and an acrylic-based resin, The particles may be formed to include at least one of Ni, Ag, or SnBi.

Here, the size of the conductive particles may be smaller than the width or height of the plurality of irregularities. As an example, the size of the conductive particles may be between 1 um and 10 um.

In addition, the melting point of the adhesive resin included in the conductive adhesive agent may be lower than the melting point of the coating layer included in the wiring. For example, the curing temperature of the adhesive resin may be between 155 ° C and 185 ° C.

A method for manufacturing a wiring used in a solar cell module according to an example of the present invention includes rotating a first roller and a second roller of a rolling machine in which a plurality of projections and depressions are formed to draw the solar cell wiring core between the first and second rollers, A step of forming a plurality of irregularities on a first portion to be connected to the electrode of the solar cell in the core and a second portion to be opposite to the first portion with respect to the center of the core; And a coating step of forming a coating layer on a surface of the core having a plurality of unevenness formed thereon.

Here, the coating step may be performed by an electroplating method.

In addition, the width of each of the first and second portions in which a plurality of irregularities are formed in the core by the rolling step may be between 100 [mu] m and 150 [mu] m.

The width of each of the plurality of irregularities formed on the surface of the first and second rollers of the rolling mill may be between 20um and 25um, and the height of each protrusion may be between 20um and 30um.

In addition, the maximum diameter of the core is between 200 탆 and 500 탆, and the thickness of the coating layer formed in the coating step may be between 1 탆 and 5 탆.

Further, before the rolling step, a cutting step of cutting the first portion and the second portion of the core having a circular cross section may be further included. At this time, the width of each of the first portion and the second portion cut at the cutting step may be between 100um and 150um.

According to another aspect of the present invention, there is provided a method of manufacturing a wiring for use in a solar cell module, comprising: a coating step of coating a surface of a solar cell wiring core to form a coating layer; And rotating the first roller and the second roller of the rolling machine in which the plurality of projections and depressions are formed to draw the core having the coating layer between the first and second rollers to form a first portion to be connected to the electrode of the solar cell in the core in which the coating layer is formed, And a rolling step of forming a plurality of concavities and convexities on a second portion which is an opposite surface of the first portion with respect to the center.

Also, prior to the coating step, cutting the first and second portions of the core having a circular cross-section may be further included.

A solar cell module according to the present invention includes a plurality of interconnections for electrically connecting a plurality of adjacent solar cells to each other and a plurality of projections and depressions formed on a portion connected to the electrodes are used to (1) (2) a conductive adhesive without solder can be used to bond the wiring and the electrode, thereby further reducing the manufacturing cost, and (3) the conductive adhesive which is cured at a low temperature with the conductive adhesive The temperature of the tabbing process for connecting the wires and the electrodes to each other can be performed at a low temperature between 155 ° C. and 185 ° C. and the buckling phenomenon in which the semiconductor substrate is bent due to the thermal expansion stress in the tabbing process Can be minimized.

In addition, the wiring of the present invention is also formed on a side opposite to a portion where a plurality of projections and depressions are connected to the electrode, so that light incident on the wiring can be diffusedly reflected so as to enter the semiconductor substrate again, .

In addition, the manufacturing method of the wiring used in the solar cell module according to the present invention can simplify the manufacturing process.

1 to 3 are views for explaining an example of a solar cell module to which a solar cell according to the present invention is applied.
4 is a partial perspective view for explaining an example of a solar cell applied to the solar cell module of FIG.
5 is a view for explaining an example of wiring applied to an example of a solar cell module according to the present invention.
6 is a view for explaining various patterns of irregularities formed on the first and second portions of the wiring according to the present invention.
7 is a view for explaining an example in which the wiring according to the present invention is connected to the electrode of a solar cell through a conductive adhesive.
8 is a view for explaining another example in which the wiring according to the present invention is connected to the electrode of the solar cell through the conductive adhesive.
9 is a flowchart for explaining a method of manufacturing a wiring according to the first embodiment of the present invention.
Fig. 10 is a view for explaining the shape of a rolling mill and a wire to be manufactured in accordance with the procedure of Fig. 9; Fig.
11 is a flowchart for explaining a modification of the method of manufacturing a wiring according to the first embodiment of the present invention.
12 is a diagram for explaining the form of wiring according to the flow chart of FIG.
13 is a flowchart for explaining a method of manufacturing a wiring according to the second embodiment of the present invention.
FIG. 14 is a view for explaining the form of wiring according to the flowchart shown in FIG. 13; FIG.
15 is a flowchart for explaining a modification of the method of manufacturing a wiring according to the second embodiment of the present invention.
FIG. 16 is a view for explaining the form of wiring according to the flowchart shown in FIG. 15. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

In the drawings, the thickness is enlarged to clearly represent the layers and regions. When a layer, film, region, plate, or the like is referred to as being "on" another portion, it includes not only the case directly above another portion but also the case where there is another portion in between. Conversely, when a part is "directly over" another part, it means that there is no other part in the middle. Further, when a certain portion is formed as "whole" on another portion, it means not only that it is formed on the entire surface of the other portion but also that it is not formed on the edge portion.

Hereinafter, the front surface may be one surface of the semiconductor substrate to which the direct light is incident, and the rear surface may be the opposite surface of the semiconductor substrate in which direct light is not incident, or reflected light other than direct light may be incident.

In the following description, the meaning of two different components having the same length or width means that they are equal to each other within an error range of 10%.

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

1 to 3 are views for explaining an example of a solar cell module to which a solar cell according to the present invention is applied. Here, FIG. 1 shows a solar cell module viewed from the front, FIG. 2 is a cross- Fig. 3 is a cross-sectional view taken along line CS2-CS2 in Fig. 1. Fig. 4 is a partial perspective view for explaining an example of a solar cell according to the present invention applied to FIG.

1 to 3, a solar cell module according to the present invention includes a plurality of solar cells C1 and C2 and a plurality of wirings 300 connected to the respective solar cells C1 and C2 .

The first and second solar cells C1 and C2 may include a first electrode 140 on the front surface of the semiconductor substrate 110 and a second electrode 150 on the rear surface thereof.

Here, the first and second electrodes 140 and 150 of each of the first and second solar cells C1 and C2 may be elongated in a stripe shape in the first direction x.

The first and second solar cells C1 and C2 are arranged in a second direction y intersecting with the first direction x and are electrically connected by a plurality of wirings 300 extending long in the second direction y They can be electrically connected to each other.

For example, each of the plurality of wirings 300 is connected to the first electrode 140 of the first solar cell C1 and the second electrode 150 of the second solar cell C2, (C1, C2) connected in series to each other.

Here, although not shown in FIGS. 1 and 2, when a plurality of wirings 300 are connected to the first electrode 140 and the second electrode 150 of each solar cell, a conductive adhesive (not shown) Can be connected. The configuration in which the plurality of wirings 300 are connected to the electrodes of the respective solar cells through the conductive adhesive is described in more detail with reference to Figs. 7 and 8. Fig.

At this time, the number of the plurality of wirings 300 may be 6 to 33 based on one surface of the solar cell. In addition, the width of each of the plurality of wirings 300 may be between 200 [mu] m and 500 [mu] m.

For example, when the line width of the wiring 300 is 200um or more and less than 300um, the number of the wirings 300 may be 15 to 33. When the line width of the wiring 300 is more than 300um and less than 350um, the number of the wirings 300 may be 10 to 15. When the line width of the wiring 300 is more than 350um and less than 400um, The number of wirings 300 may be 6 to 8 when the line width of the wiring 300 is 400 to 500 mu m.

The number of wirings 300 is arranged differently according to the line width of the wiring 300 so that the total shading area covered by the wiring 300 on the light receiving surface of the solar cell is not increased, It is possible to appropriately adjust the self-resistance of the solar cell module 300, thereby minimizing the output reduced by the wiring 300 and further improving the output of the solar cell module.

The relationship between the number of wires 300 according to the line widths described above is only one example optimized, and the present invention is not necessarily limited thereto.

3, the pitch 300P between two wirings 300 that are connected to the first electrode 140 or the second electrode 150 and are adjacent to each other, And may be formed to be between 4.75 mm and 25.13 mm in consideration of the line width, the number, and the shading area of the wiring 300.

1 and 2, the wiring 300 connected to the first electrode 140 of the first solar cell C1 through the conductive adhesive directly contacts the second electrode 150 of the second solar cell with a conductive adhesive Another separate wiring 300 extending long in the first direction x is provided between the first solar cell and the second solar cell, and the first solar cell The wiring 300 connected to the first electrode 140 of the first solar cell C1 through the conductive adhesive and the wiring 300 connected to the second electrode 150 of the second solar cell through the conductive adhesive are connected to the separate wiring 300, And the first solar cell and the second solar cell may be connected in series.

4, the solar cell includes a semiconductor substrate 110, an emitter layer 120, an antireflection film 130, a first electrode 140, A back surface field (BSF) 172, a back protection layer 180, and a second electrode 150. [

The semiconductor substrate 110 may have a first conductivity type, for example, a p-type or an n-type conductivity type. The semiconductor substrate 110 may be formed of any one of single crystal silicon, polycrystalline silicon, have. In one example, the semiconductor substrate 110 may be formed of a crystalline silicon wafer. However, the semiconductor substrate 110 is not necessarily limited to such a silicon wafer, but a GaAs substrate may also be used.

Specifically, when the semiconductor substrate 110 has a p-type conductivity type, impurities of boron, gallium, indium, and other trinary elements are doped in the semiconductor substrate 110. Alternatively, however, the semiconductor substrate 110 may be of the n-type conductivity type. Impurities of pentavalent elements such as phosphorus (P), arsenic (As), and antimony (Sb) may be doped into the semiconductor substrate 110 when the semiconductor substrate 110 has an n-type conductivity type.

The front surface of the semiconductor substrate 110 has a plurality of uneven surfaces. 4, only the edge portion of the semiconductor substrate 110 is shown as an uneven surface, but substantially the entire front surface of the semiconductor substrate 110 has an uneven surface, The antireflection film 120 and the antireflection film 130 may have uneven surfaces.

As shown in FIG. 4, the emitter layer 120 is formed on the entire surface of the first conductive type semiconductor substrate 110, which is the incident surface, and is of a second conductive type opposite to the first conductive type, for example, n Impurity of the conductive type can be doped into the semiconductor substrate 110 and be located on the surface where the light is incident, that is, inside the front surface of the semiconductor substrate 110. Thus, the emitter portion 120 of the second conductivity type forms a p-n junction with the first conductive type portion of the semiconductor substrate 110.

Light incident on the semiconductor substrate 110 is separated into electrons and holes, so that the electrons move toward the n-type and the holes move toward the p-type. Therefore, when the semiconductor substrate 110 is p-type and the emitter section 120 is n-type, the separated holes move toward the back surface of the semiconductor substrate 110, and the separated electrons can move toward the emitter section 120.

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

When the emitter section 120 has an n-type conductivity type, the emitter section 120 may be formed by doping an impurity of a pentavalent element into the semiconductor substrate 110. Conversely, when the emitter section 120 has a p-type conductivity type, And may be formed by doping an impurity of a trivalent element into the semiconductor substrate 110.

4 and 5, when the emitter section 120 is located on the incident surface of the semiconductor substrate 110, the antireflection film 130 is disposed on the incident surface of the semiconductor substrate 110, The antireflection film 130 may be disposed on the emitter layer 120.

The antireflection film 130 may include a hydrogenated silicon nitride film (SiNx: H), a hydrogenated silicon oxide film (SiOx: H), a hydrogenated silicon nitride oxide film (SiNxOy: H), and a hydrogenated amorphous silicon May be formed as a plurality of layers.

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

4, the plurality of first electrodes 140 are located on the front surface of the semiconductor substrate 110 and are spaced apart from each other on the front surface of the semiconductor substrate 110, You can stretch it long.

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

Accordingly, the plurality of first electrodes 140 can collect charges, for example, electrons, which have migrated toward the emitter section 120.

The rear electric field portion 172 may be located on the rear surface opposite to the front surface of the semiconductor substrate 110 and may include an impurity of the first conductivity type identical to that of the semiconductor substrate 110 in a region doped at a higher concentration than the semiconductor substrate 110 , For example, a P + region.

The rear electric field portion 172 may be formed in a plurality of lines spaced apart in the second direction y by forming a long line in the first direction x in a superposed connection with the second electrode 150 pattern, have. Thus, the backside electrical section 172 may be comprised of a plurality of backside electrical line sections 172.

A potential barrier is formed due to the difference in impurity concentration between the semiconductor substrate 110 and the rear electric field portion 172, thereby hindering electron movement toward the rear electric field portion 172, which is the direction of movement of the holes, It is possible to facilitate the movement of holes toward the light emitting layer 172.

Therefore, it is possible to reduce the amount of charge lost due to the recombination of electrons and holes at the back surface and the vicinity of the semiconductor substrate 110 and to accelerate the movement of a desired charge (e.g., a hole) .

The backside passivation layer 180 may be formed to cover the entire rear surface of the semiconductor substrate 110 except for the 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. At least one of the silicon nitride (SiNx), silicon oxide (SiOx), or silicon oxynitride (SiNxOy) may be formed of at least one layer.

The second electrode 150 is formed in parallel with the first direction x on the rear surface opposite to the first surface of the semiconductor substrate 110 and extends in the second direction y intersecting the first direction x. And can be formed spaced apart.

The second electrode 150 may be electrically connected to the rear electric unit 172 to collect electric charges, for example, holes moving from the rear electric unit 172 side.

Since the second electrode 150 is in contact with the rear electric part 172 which maintains the impurity concentration higher than that of the semiconductor substrate 110, the contact resistance between the rear electric part 172 and the second electrode 150 The efficiency of charge transfer from the semiconductor substrate 110 to the second electrode 150 can be improved.

The wiring 300 is connected to the second electrode 150 and the electric charge collected in the second electrode 150 can be transmitted to another adjacent solar cell through the wiring 300.

The first and second electrodes 140 and 150 may include a metal material having a good conductivity and may contain at least one conductive material, for example, silver (Ag).

4, the patterns of the first and second electrodes 140 and 150 are formed to extend in the first direction x. However, as shown in FIG. 4, the first and second electrodes 140, 140, and 150 may be provided differently.

For example, the first and second electrodes 140 and 150 may be formed in a pattern in which other electrodes extending long in the second direction y are connected to electrodes extending in a first direction x.

At this time, the other electrode extending in the second direction y may overlap with the wiring 300. Alternatively, the second electrode 150 may be provided in the form of a surface electrode covering the entire rear surface of the semiconductor substrate 110, as described above. As described above, the first and second electrodes 140 and 150 may be provided in various patterns.

Each of the plurality of wirings 300 for connecting the plurality of solar cells to each other in series through the conductive adhesive may be connected to the solar cell in the second direction y as shown in Fig. Although the illustration of the conductive adhesive agent is omitted in Fig. 4, this will be described in detail in Fig. 7 and Fig.

4, each of the plurality of wirings 300 connected to the electrodes 140 and 150 of each solar cell through a conductive adhesive in the solar cell module according to the present invention includes electrodes 140 and 150, A plurality of projections and depressions 300K are provided on the surface of the first portion 300P1 to be connected and a plurality of second portions 300P2 are formed on the surface of the second portion 300P2 opposite to the first portion 300P1 with respect to the center 300C of the wiring 300 The protrusions 300K may be provided.

The structure of the wiring 300 according to the present invention will be described in more detail as follows.

5 is a view for explaining an example of wiring applied to an example of a solar cell module according to the present invention.

5A is a cross-sectional view of the wiring 300, and FIG. 5B is a partial perspective view of the wiring 300. FIG.

As shown in FIGS. 5A and 5B, the interconnection wire 300 according to the present invention is formed on the surface of the first portion 300P1 connected to the electrodes 140 and 150, A plurality of protrusions 300K may be provided on the surface of the second portion 300P2 opposite to the first portion 300P1 with respect to the center 300C of the wiring 300 with a plurality of protrusions 300K .

The division of the first and second portions 300P1 and 300P2 of the wiring 300 can be determined based on the wiring 300 connected to the electrodes 140 and 150 of the solar cell. For example, when the wiring 300 is disposed as shown in FIGS. 1 and 2, the lower part of the wiring 300 is connected to the first electrode 140 of the first solar cell C1, An upper portion of the wiring 300 may be connected to the second electrode 150 of the battery C2.

Therefore, in the wiring 300 connected to the first solar cell C1, the lower portion can be defined as the first portion of the wiring 300, the upper portion can be defined as the second portion of the wiring, and the second solar cell C2 , An upper portion of the wiring 300 may be defined as a first portion of the wiring, and a lower portion thereof may be defined as a second portion of the wiring.

Therefore, in the present invention, the first and second portions 300P1 and 300P2 of the wiring 300 can be distinguished from the wiring 300 connected to each solar cell.

As described above, a plurality of irregularities 300K are formed on the surface of the first portion 300P1 of the wiring 300 to increase the surface area of the first portion 300P1 connected to the electrodes 140 and 150, 300 and the electrodes 140 and 150 can be further improved and a plurality of projections and depressions 300K can be formed on the surface of the second portion 300P2 of the wiring 300, The light incident on the portion 300P2 can be diffusely reflected to be re-incident on the solar cell, and the efficiency of the solar cell module can be further improved.

The wiring 300 of the solar cell module according to the present invention is formed by pressing a wire having a circular section with a rolling mill to form a plurality of projections 300K on the surfaces of the first and second portions 300P1 and 300P2 of the wiring 300 The cross section of the wiring 300 may have a circular or elliptical shape as a whole.

Therefore, irregularities 300K may not be formed on the surface of the wiring 300 between the first portion 300P1 and the second portion 300P2 except the portion where the unevenness 300K is formed by the rolling mill .

As described above, light irregularities 300K are not formed on the surfaces between the first and second portions 300P1 and 300P2 in the wiring 300, and light incident on the side surface of the wiring 300 is directly reflected toward the solar cell , The efficiency of the solar cell can be further improved.

Each of the plurality of protrusions 300K formed on the first and second portions 300P1 and 300P2 extends along the longitudinal direction of the wiring 300, that is, along the axial direction 300X of the wiring 300 And may have a groove shape.

The wiring 300 may include a core 300a and a coating layer 300b coating the surface of the core 300a.

Here, the core 300a is formed of any one of copper (Cu), silver (Ag), gold (Au), and aluminum (Al), and the coating layer 300b includes tin Alloy.

Here, the core 300a functions to transfer carriers generated in each solar cell to adjacent solar cells, the coating layer 300b prevents oxidization of the core 300a, and the wiring 300 is electrically connected to the solar cell via the conductive adhesive. It is possible to secure the adhesive force between the core 300a and the conductive adhesive agent when the electrodes are connected to the electrodes 140 and 150 of the battery.

Here, the thickness of the coating layer 300b may be smaller than the width or height of the unevenness 300K formed in the first and second portions 300P1 and 300P2. As described above, by making the thickness of the coating layer 300b smaller than the width or the height of the unevenness 300K, the first and second portions 300P1 and 300P2 of the core 300a can be formed while minimizing the cost of forming the coating layer 300b. The unevenness 300K formed on the surface of the coating layer 300b can be expressed directly on the surface of the coating layer 300b. Accordingly, a plurality of projections and depressions 300K can be directly formed on the surfaces of the first and second portions 300P1 and 300P2 of the wiring 300.

However, when the thickness of the coating layer 300b is formed to be excessively larger than the width or height of the unevenness 300K, the first and second portions 300P1 and 300P2 are formed by the coating layer 300b, The unevenness 300K may disappear and the unevenness 300K may not be developed on the surface of the wiring 300 by the coating layer 300b. In this case, the increase in the surface area of the first portion 300P1 may be relatively reduced, the adhesion between the wiring 300 and the electrodes 140 and 150 may not reach a desired level, The light reflection by the second portion 300P2 may not be performed smoothly.

Here, the maximum diameter (R300) of the core (300a) can be set to be between 200 [mu] m and 500 [mu] m, taking into consideration the shading area and number of the wirings (300).

The thickness of the coating layer 300b is preferably 1um or more to prevent oxidation of the wiring 300 so that the irregularities 300K formed on the first and second portions 300P1 and 300P2 of the core 300a are electrically connected to the wiring 300, The thickness of the first and second portions 300P1 and 300P2 may be 5 μm or less in order to minimize the formation cost of the coating layer 300b.

The width or height of each of the plurality of protrusions 300K formed on the first and second portions 300P1 and 300P2 may be greater than the thickness of the coating layer 300b and the width or height of the plurality of protrusions 300K formed on the first and second portions 300P1 and 300P2, The width of each of the concave and convex portions 300K is between 20um and 25um and the height of each of the plurality of concave and convex portions 300K formed in the first and second portions 300P1 and 300P2 is between 20um and 30um.

5A, the widths of the irregularities 300K located at the outermost portions of the first and second portions 300P1 and 300P2 in the first and second portions 300P1 and 300P2, respectively, The height may be smaller than the width or height of the unevenness 300K located at the center of the first and second portions 300P1 and 300P2. This may be a characteristic when the core 300a having a circular cross section is rolled by a roller of the rolling mill in which the projections and depressions 300K are formed.

As described above, when the core 300a having a circular section is rolled by a roller of a rolling mill in which the projections and depressions 300K are formed to form the irregularities 300K on the first and second portions 300P1 and 300P2 of the wiring 300 , The process is simple and the cost for forming the concavities and convexities 300K on the first and second portions 300P1 and 300P2 of the wiring 300 can be minimized.

In addition, the width W300P of the first and second portions 300P1 and 300P2 in which the plurality of irregularities 300K are formed in the wiring 300 can be formed to be between 100 μm and 150 μm. The reason why the width W300P of each of the first and second portions 300P1 and 300P2 is set to be equal to or greater than 100 μm is to increase the surface area of the portion of the wiring 300 bonded to the electrodes 140 and 150, To the minimum.

The width W300P of each of the first and second portions 300P1 and 300P2 is set to 150um or less because the width W300P of each of the first and second portions 300P1 and 300P2 is excessively larger than the above- The pressure of the rolling mill excessively increases due to the characteristic of forming the irregularities 300K by pressing the wiring 300 with the rolling mill so that the overall shape of the wiring 300 can be flattened, The irregularities 300K are not formed between the surfaces 300P1 and 300P2, and the surface area of the wiring 300 formed by the curved surface may be reduced.

In this way, when the wiring 300 has a flat shape, the optical effect by the wiring 300 may not be secured as much as desired.

The unevenness 300K formed in the first and second portions 300P1 and 300P2 of the wiring 300 has been described as an example having a groove shape extending long along the central axis 300X of the wiring 300. However, Here, the shapes of the protrusions 300K formed in the first and second portions 300P1 and 300P2 of the wiring 300 may have various shapes. This will be described in more detail as follows.

6 is a view for explaining various patterns of the irregularities 300K formed on the first and second portions 300P1 and 300P2 of the wiring 300 according to the present invention.

6 (a), 6 (a), 6 (c) and 6 (e) are partial perspective views of the wiring 300, And FIG. 6 (d) is a top view of the wiring 300 shown in FIG. 6 (c).

As shown in FIG. 6, the irregularities 300K of the wiring 300 according to the present invention may be formed variously, unlike in FIG.

 Specifically, as shown in Figs. 6A and 6B, the unevenness 300K formed in the first and second portions 300P1 and 300P2 of the wiring 300 is the center axis 300X of the wiring 300 The first and second portions 300P1 and 300P2 of the wiring 300 may be formed so as to have a groove shape extending in the width direction crossing the wiring 300. As shown in FIGS. 6C and 6D, And 300P2 may be formed to have a groove shape extending long in an oblique direction to the central axis 300X of the wiring 300. [

Alternatively, irregularities 300K formed on the first and second portions 300P1 and 300P2 of the wiring 300 may be formed to have a pyramid shape as shown in FIG. 6E, or alternatively, an inverted pyramid shape .

As described above, the irregularities 300K formed on the first and second portions 300P1 and 300P2 of the wiring 300 according to the present invention can have various patterns.

As shown in FIG. 4, when the wiring 300 having the concave and convex portions 300K on the first and second portions 300P1 and 300P2 is connected to the semiconductor substrate 110 on the front and rear surfaces of the solar cell, , And may be connected through a conductive adhesive. For this, referring to FIGS. 7 and 8, which is an enlarged view of the portion A in FIG. 3, the following description will be given.

FIG. 7 is a view for explaining an example in which the wiring according to the present invention is connected to the electrode of the solar cell through the conductive adhesive, and FIG. 8 is a view for explaining another example in which the wiring according to the present invention is connected to the electrode of the solar cell through the conductive adhesive Fig.

7 and 8 illustrate the case where the wiring 300 is connected to the first electrode 140 of the solar cell as an example. However, when the wiring 300 is connected to the second electrode 150, have.

7 and 8 illustrate only the case where the wiring 300 is connected to the electrodes 140 and 150 through the conductive adhesive 200. However, the wiring 300 and the electrodes 140 and 150 do not overlap each other The wiring 300 and the semiconductor substrate 110 can be bonded to each other through the conductive adhesive 200 in the region of the semiconductor substrate 110 where the semiconductor substrate 110 is not formed.

7, when the wiring 300 is connected to the electrodes 140 and 150 of the solar cell, for example, the first electrode 140, the wiring 300 may be connected through the conductive adhesive 200. Here, the material of the conductive adhesive 200 may be, for example, in the form of a solder paste containing tin (Sn) or tin (Sn) alloy.

The width W200 of the conductive adhesive 200 is larger than the width W300P of the first portion 300P1 or the second portion 300P2 connected to the conductive adhesive 200 and the maximum line width R300) (or diameter). Here, the width W200 of the conductive adhesive 200 means the width in the line width direction of the wiring 300, that is, the width in the first direction (x).

The width W200 of the conductive adhesive 200 is formed to be larger than the width W300P of the first portion 300P1 or the second portion 300P2 of the wiring 300, The electrodes 140 and 150 can have a sufficient adhesive force and a low contact resistance and the width W200 of the conductive adhesive 200 is made smaller than the maximum line width R300 of the wiring 300, The shading area where the semiconductor substrate 110 is covered can be minimized. The width W200 of the conductive adhesive 200 may be, for example, between 320 and 380 μm.

8, the conductive adhesive 200 may include a plurality of conductive particles (not shown) in the adhesive resin 200S, as shown in FIG. 7. In the conductive adhesive 200, 200P may be distributed and formed.

Here, the adhesive resin 200S of the conductive adhesive 200 may be formed of at least one of an epoxy-based resin, a silicone-based resin, and an acrylic-based resin, and the conductive particles 200P may be at least one selected from the group consisting of Ni, Ag Or < RTI ID = 0.0 > SnBi. ≪ / RTI >

Here, the size of the conductive particles 200P may be smaller than the width or height of the plurality of irregularities 300K. For example, the size of the conductive particles 200P may be between 1 um and 10 um.

The adhesive resin 200S of the conductive adhesive 200 can sufficiently secure the physical adhesive force between the wiring 300 and the electrodes 140 and 150 and the semiconductor substrate 110. [

The unevenness 300K formed in the first portion 300P1 of the wiring 300 during the tableting process for connecting the wiring 300 to the solar cell causes the conductive particles 200P in the adhesive resin 200S to contact the wiring 300 So that the conductive particles 200P are stably positioned between the irregularities 300K of the wiring 300 and the electrodes 140 and 150 so that the wiring 300 and the electrodes 140, 150 can be sufficiently lowered.

The melting point of the adhesive resin 200S included in the conductive adhesive 200 may be lower than the melting point of the coating layer 300b included in the wiring 300. [

As described above, according to the present invention, the curing temperature of the adhesive resin 200S is set to be lower than that of the coating layer 300b of the wiring 300, so that irregularities formed on the surface of the first portion 300P1 of the wiring 300 during the tabletting process The conductive particles 200P of the conductive adhesive 200 in the tableting process can be held in the first portion 300P1 in which the plurality of irregularities 300K are formed, So that the wiring 300 and the electrodes 140 and 150 can have sufficiently low contact resistance.

At this time, the curing temperature of the adhesive resin 200S may be, for example, between 155 ° C and 185 ° C. As described above, according to the present invention, the curing temperature of the adhesive resin 200S of the conductive adhesive 200 is made sufficiently low to lower the temperature of the tableting process, and the wiring 300 or the electrodes 140 and 150, It is possible to prevent the semiconductor substrate 110 from buckling due to the thermal expansion stress of the semiconductor substrate 110.

The structure of the wiring 300 applied to the solar cell module according to the present invention and the solar cell module according to the present invention has been described so far. Hereinafter, the first and second portions 300P1 and 300P2 of the wiring 300 will be described. (300K) are formed.

FIG. 9 is a flow chart for explaining a method of manufacturing a wiring according to the first embodiment of the present invention, and FIG. 10 is a view for explaining a form of a wire and a wire to be manufactured, in which a wire is manufactured according to the procedure of FIG.

10A is a perspective view schematically illustrating a rolling mill 400 having first and second rollers R1 and R2 having a plurality of irregularities 300K formed on its surface and FIG. (C) is a view of the rolling mill 400 viewed from the top. 10D is a sectional view of the core 300a before and after the rolling step S1 and FIG. 10E is a sectional view of the wiring 300 in which the coating step S2 is performed. It is.

As shown in FIG. 9, a method of manufacturing the wiring 300 used in the solar cell module according to an example of the present invention may include a rolling step S1 and a coating step S2.

In the rolling step S1, the rolling mill 400 having the first roller R1 and the second roller R2 may be used as shown in Figs. 10 (a) to (c).

Here, a plurality of unevenness RK can be formed on the surfaces of the first and second rollers R1 and R2.

5, when the irregularities 300K having a groove shape in parallel with the axis of the wiring 300 are to be formed in the wiring 300, the surface of the first and second rollers R1 and R2 A plurality of protrusions RK may be formed and each of the plurality of protrusions RK may have a shape in which the protrusions are elongated in a direction perpendicular to the rotation axis XR of each of the first and second rollers R1 and R2.

6 (a), when the irregularities 300K having a groove shape crossing the axis of the wiring 300 are to be formed on the wiring 300, the first and second rollers R1, A roller in which protrusions of protrusions and protrusions RK are elongated in a direction parallel to the rotation axis XR of each of the rollers Rl and R2 may be used.

6 (c), when the irregularities 300K having a groove shape in the oblique direction on the axis of the wiring 300 are to be formed in the wiring 300, the first and second rollers R1 and R2 A roller in which protrusions of protrusions and protrusions RK are elongated obliquely in each rotation axis can be used.

The width of each of the plurality of irregularities RK formed on the surfaces of the first and second rollers R1 and R2 of the rolling mill 400 may be between 20 um and 25 um and the height of each protrusion may be between 20 um and 30 um. Alternatively, however, the width and protrusion height of the unevenness RK may have different numerical ranges.

As shown in Figs. 10 (b) and 10 (c), in the state in which the rolling mill 400 having the first and second rollers R1 and R2 provided with the plurality of protrusions RK is prepared, The rolling step S1 may be performed by rotating the first roller R1 and the second roller R2 to draw the solar cell wiring core 300a between the first and second rollers R1 and R2. At this time, the solar cell wiring core 300a may be a metal wire having a maximum diameter of 200 to 500 μm and a circular cross section.

10 (d), the core 300a having a circular shape in cross section before the rolling step S1 is deformed by the pressure applied by the first and second rollers R1 and R2 After the rolling step S1, a plurality of irregularities 300K may be formed in the first portion 300P1 and the second portion 300P2 of the core 300a.

In the rolling step S1, a plurality of irregularities 300K are formed on the first and second parts 300P1 and 300P2 of the core 300a. The width W300P of each of the first and second parts 300P1 and 300P2 The first and second rollers 300R and 300R are formed such that the width of the unevenness 300K formed in the first and second portions 300P1 and 300P2 is between 20um and 25um and the height of the unevenness 300K is between 20um and 30um, R1 and R2 can be adjusted.

After the rolling step S1, as shown in FIG. 9, a coating step S2 for forming a coating layer 300b on the surface of the core 300a having a plurality of concavities and convexities 300K may be performed.

Such a coating step S2 may be performed, for example, by an electroplating method, such that the thickness of the coating layer 300b is between 1 [mu] m and 5 [mu] m.

By the rolling step S1 and the coating step S2, the wiring 300 of the present invention as described in Fig. 5 can be completed.

In the method of manufacturing the wiring 300 according to the first embodiment of the present invention, a method of forming the wiring 300 of the present invention by directly rolling the solar cell wiring core 300a having a circular section in the form of a coating, The first and second portions 300P1 and 300P2 may be cut first and then the rolling step S1 and the coating step S2 may be performed in the core 300a having a circular shape in section. This will be described in more detail as follows.

Fig. 11 is a flowchart for explaining a modification of the method of manufacturing a wiring according to the first embodiment of the present invention, and Fig. 12 is a diagram for explaining a wiring form according to the flowchart of Fig.

11, a modification of the manufacturing method of the wiring 300 according to the first embodiment of the present invention may include a cutting step S0, a rolling step S1, and a coating step S2 .

Here, the cutting step S0 may be performed before the rolling step S1. In the cutting step S0, as shown in Fig. 12 (a), in the core 300a having a circular section, The first and second portions 300P1 and 300P2 of the core 300a can be cut so that the first and second portions 300P1 and 300P2 of the core 300a can be cut as shown in FIG.

In this cutting step S0, the core 300a may be cut so that the width of each of the first portion 300P1 and the second portion 300P2 may be between 100 μm and 150 μm.

Thereafter, the rolling step S1 is performed to form a plurality of concave and convex portions 300K on each of the first and second portions 300P1 and 300P2, as shown in Fig. 12C, S2 may be performed so that the coating layer 300b may be formed on the surface of the core 300a as shown in Figure 12 (d).

Here, the description of the rolling step S1 and the coating step S2 is the same as the manufacturing method of the wiring 300 according to the first embodiment of the present invention, which is omitted.

Although the case where the coating step S2 is performed after the rolling step S1 is performed is described as an example of the method of manufacturing the wiring 300 so far, the order of the rolling step S1 and the coating step S2 is It is also possible to carry out the change. This will be described in more detail as follows.

FIG. 13 is a flowchart for explaining a method of manufacturing a wiring according to the second embodiment of the present invention, and FIG. 14 is a view for explaining the form of wiring according to the flowchart shown in FIG.

As shown in Fig. 13, in the method of manufacturing the wiring 300 according to the second embodiment of the present invention, the rolling step S2 'may be performed after the coating step S1' is performed.

The coating step S1 'is performed by coating the surface of the solar cell wiring core 300a having a circular section as shown in Fig. 14 (a) The coating layer 300b may be formed on the surface of the substrate 300a. In the step of forming the coating layer 300b, an electroplating method may be used as in the method of manufacturing the wiring 300 according to the first embodiment, and the thickness of the coating layer 300b may be between 1 and 5 um.

The first roller R1 and the second roller R2 of the rolling mill 400 having the plurality of projections 300K are rotated to rotate the core 300a on which the coating layer 300b is formed by the first and second rollers R1 The electrode 300 of the photovoltaic cell of the present invention may be connected to the electrode of the solar cell 140 in the core 300a on which the coating layer 300b is formed, as shown in FIG. 14 (c) A plurality of protrusions 300K are formed on the first portion 300P1 to be connected to the first portion 300P1 and the second portion 300P2 that is the opposite surface of the first portion 300P1 with respect to the center of the core 300a, The wiring 300 according to the invention can be formed.

In addition, in the method of manufacturing the wiring 300 according to the second embodiment of the present invention, the cutting step may be further performed as in the modification of the first embodiment. This will be described in more detail as follows.

FIG. 15 is a flowchart for explaining a modification of the method of manufacturing a wiring according to the second embodiment of the present invention, and FIG. 16 is a view for explaining a wiring form according to the flowchart shown in FIG.

As shown in Fig. 15, a modification of the manufacturing method of the wiring 300 according to the second embodiment of the present invention includes a cutting step S0 ', a coating step S1' and a rolling step S2 ' can do.

Here, the cutting step S0 'may be performed before the coating step S1'. In the cutting step S0 ', as shown in FIG. 16 (a), the core 300a having a circular section The first portion 300P1 and the second portion 300P2 are cut so that the first and second portions 300P1 and 300P2 of the core 300a can be cut as shown in Fig. 16B.

Thereafter, the coating step S1 'is performed to form a coating layer 300b on the surface of the core 300a having the first and second portions 300P1 and 300P2 cut, as shown in FIG. 16C. .

Thereafter, a rolling step S2 'is carried out to form a plurality of irregularities 300K on each of the first and second portions 300P1 and 300P2 of the wiring 300, as shown in Fig. 16D .

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

Claims (25)

A plurality of solar cells each having a semiconductor substrate and electrodes formed on a surface of the semiconductor substrate; And
And a plurality of wires connected to electrodes provided in each of the plurality of solar cells via a conductive adhesive so as to electrically connect a plurality of adjacent solar cells among the plurality of solar cells,
Wherein the wiring comprises a core and a coating layer coating the surface of the core,
Wherein each of the plurality of wirings includes a plurality of wiring irregularities on a surface of a first portion connected to the electrode and a plurality of wiring irregularities on a surface of a second portion opposite to the first portion with respect to a center of the wiring,
Wherein a plurality of core irregularities are provided in the first and second portions of the core,
Wherein the plurality of wiring concavities and convexities have a shape in which the corrugated concavo-convex shape is formed on the first and second partial surfaces of the coating layer,
The cross section of the wiring has a circular or elliptical shape as a whole,
The concavities and convexities are not formed on the surface between the first portion and the second portion in the wiring,
The width and the height of the irregularities located at the outermost portions of the first and second portions of each of the first and second portions are smaller than the width and height of the irregularities located at the center portions of the first and second portions,
Wherein the thickness of the coating layer is smaller than the width or height of the core irregularities formed in the first and second portions of the core. delete The method according to claim 1,
Wherein the core is formed of any one of copper (Cu), silver (Ag), gold (Au), and aluminum (Al), and the coating layer is made of an alloy containing tin (Sn) module. The method of claim 3,
The maximum diameter of the core is between 200 um and 500 um,
Wherein the thickness of the coating layer is between 1 [mu] m and 5 [mu] m. The method of claim 3,
Wherein a width or a height of each of the plurality of wiring irregularities formed in the first and second portions is larger than the thickness of the coating layer,
The width of each of the plurality of wiring concaves and convexes formed in the first and second portions is between 20um and 25um,
Wherein a height of each of the plurality of wiring irregularities formed in the first and second portions is between 20um and 30um. delete The method according to claim 1,
Wherein each of the plurality of wiring irregularities formed in the first and second portions has a groove shape extending long along the longitudinal direction, the width direction, or the oblique direction of the wiring, or has a pyramid shape. The method according to claim 1,
Wherein a width of the first and second portions in which the plurality of wiring irregularities are formed in the wiring is between 100 mu m and 150 mu m. The method according to claim 1,
Wherein a width of the conductive adhesive is larger than a width of the first portion or the second portion connected to the conductive adhesive and smaller than a maximum line width of the wiring. 10. The method of claim 9,
Wherein a width of the conductive adhesive is between 320 [mu] m and 380 [mu] m. The method according to claim 1,
The conductive adhesive may be in the form of a solder paste containing tin (Sn) or may be in the form of a conductive adhesive paste in which a plurality of conductive particles are distributed in the adhesive resin. 12. The method of claim 11,
Wherein the conductive adhesive is formed by distributing a plurality of conductive particles in the adhesive resin,
Wherein the adhesive resin is formed of at least one of an epoxy-based resin, a silicone-based resin, and an acrylic-based resin,
Wherein the conductive particles include at least one of Ni, Ag, and SnBi. 13. The method of claim 12,
And the size of the conductive particles is smaller than the width or the height of the plurality of wiring irregularities. 13. The method of claim 12,
And the size of the conductive particles is between 1 [mu] m and 10 [mu] m. 13. The method of claim 12,
Wherein the melting point of the adhesive resin contained in the conductive adhesive agent is lower than the melting point of the coating layer included in the wiring. 13. The method of claim 12,
Wherein the curing temperature of the adhesive resin is between 155 ° C and 185 ° C. The first roller and the second roller of the rolling mill in which a plurality of projections and depressions are formed are rotated to draw the solar cell wiring core between the first and second rollers to form a first portion to be connected to the electrode of the solar cell in the core, A rolling step of forming a plurality of corrugated irregularities on a second portion which is an opposite side of the first portion with respect to the reference; And
And a coating step of forming a coating layer on a surface of the core having the plurality of core irregularities formed thereon,
The solar cell wiring core has a circular or elliptical shape in cross section as a whole,
The core unevenness is not formed on the surface between the first portion and the second portion of the solar cell wiring core by the rolling step,
The width and height of the irregularities located at the outermost portions of the first and second portions in the plurality of core irregularities formed in each of the first and second portions by the rolling step are located in the middle portion of each of the first and second portions Is smaller than the width and height of the core irregularities,
Wherein the thickness of the coating layer formed in the coating step is smaller than the width or height of the core irregularities formed in the first and second portions of the core, Wherein a plurality of the projected irregularities of the wiring are formed. 18. The method of claim 17,
Wherein the coating step is performed by an electroplating method. 18. The method of claim 17,
Wherein a width of each of the first and second portions in which a plurality of corrugated irregularities are formed in the core by the rolling step is in the range of 100um to 150um. 18. The method of claim 17,
Wherein the width of each of the plurality of core irregularities formed on the surfaces of the first and second rollers of the rolling mill is between 20um and 25um and the height of each protrusion is between 20um and 30um. 18. The method of claim 17,
The maximum diameter of the core is between 200 um and 500 um,
Wherein the thickness of the coating layer formed in the coating step is between 1 [mu] m and 5 [mu] m. 18. The method of claim 17,
And cutting the first portion and the second portion of the core having a circular cross section prior to the rolling step. 23. The method of claim 22,
Wherein a width of each of the first portion and the second portion cut in the cutting step is between 100um and 150um. A coating step of coating a surface of a solar cell wiring core to form a coating layer; And
A first portion to be connected to an electrode of the solar cell in a core in which the coating layer is formed by rotating a first roller and a second roller of a rolling machine having a plurality of unevenness to draw a core having the coating layer therebetween between first and second rollers, And forming a plurality of wiring irregularities on a second portion which is an opposite surface of the first portion with respect to the center of the core,
The solar cell wiring core has a circular or elliptical shape in cross section as a whole,
The wiring step is not formed on the surface between the first portion and the second portion of the solar cell wiring core by the rolling step,
A plurality of core irregularities are formed in the first and second portions of the core by the rolling step, the core irregularities of the plurality of wiring irregularities have a shape developed on the first and second partial surfaces of the coating layer,
The width and height of the irregularities located at the outermost portions of the first and second portions in the plurality of wiring irregularities formed in the first and second portions by the rolling step are located in the middle portions of the first and second portions, Is smaller than the width or height of the concave /
Wherein the thickness of the coating layer formed in the coating step is smaller than the width or height of the core irregularities formed in the first and second portions of the core. 25. The method of claim 24,
And cutting the first portion and the second portion of the core having a circular cross section prior to the coating step.

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