KR101816180B1 - Solar cell module - Google Patents

Abstract

The present invention relates to a solar cell module.
A solar cell module according to an exemplary embodiment of the present invention includes a semiconductor substrate and a plurality of first and second solar cell modules arranged in a first direction and extending in a second direction crossing the first direction, A plurality of solar cells having electrodes; And a plurality of second conductive wirings arranged in a first direction on the rear surface of the semiconductor substrate of each of the plurality of solar cells, the plurality of first conductive wirings connected to the plurality of first electrodes and the plurality of second conductive wirings connected to the plurality of second electrodes; A plurality of first conductive wires arranged in a second direction between first and second solar cells arranged adjacent to each other of the plurality of solar cells and connected to the first solar cell and a plurality of first conductive wires connected to the second solar cell, Wherein the first and second conductive wirings include a first coating layer connected to the conductive core and the first and second electrodes, and a second coating layer connected to the inter-cell connector, And the melting point of the first coating layer and the melting point of the second coating layer are different from each other.

Description

Solar cell module {SOLAR CELL MODULE}

The present invention relates to a solar cell module.

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.

A plurality of such solar cells may be formed as modules by being connected to each other by inter-cell connectors.

On the other hand, in the back-surface solar cell in which all of the electrodes in the solar cell are connected to the rear surface, the metal wiring is connected to the electrode located on the rear surface of the semiconductor substrate through the conductive adhesive, and the metal wiring is connected to the inter- .

Here, the metal wiring can be expanded in length during the heat treatment process for connecting the metal wiring to the inter-cell connector, thereby deteriorating the physical adhesion between the metal wiring and the inter-cell connector, resulting in disconnection.

An object of the present invention is to provide a solar cell module with improved physical adhesion between a metal wiring and an inter-cell connector, thereby further improving reliability.

A solar cell module according to an exemplary embodiment of the present invention includes a semiconductor substrate and a plurality of first and second solar cell modules arranged in a first direction and extending in a second direction crossing the first direction, A plurality of solar cells having electrodes; And a plurality of second conductive wirings arranged in a first direction on the rear surface of the semiconductor substrate of each of the plurality of solar cells, the plurality of first conductive wirings connected to the plurality of first electrodes and the plurality of second conductive wirings connected to the plurality of second electrodes; A plurality of first conductive wires arranged in a second direction between first and second solar cells arranged adjacent to each other of the plurality of solar cells and connected to the first solar cell and a plurality of first conductive wires connected to the second solar cell, Wherein the first and second conductive wirings each comprise a conductive core and a conductive coating layer for coating the surface of the core, and the conductive coating layer is connected to the first and second electrodes And a second coating layer connected to the intercell connector, wherein a melting point of the first coating layer and a melting point of the second coating layer are different from each other.

In one example, the melting point of the first coating layer may be higher than the melting point of the second coating layer.

Here, the first coating layer may be located at the end of each of the plurality of first and second conductive wirings, and the second coating layer may be located at the remaining portion except for the ends of the plurality of first and second conductive wirings.

More specifically, each of the plurality of first and second conductive wirings includes a cell portion overlapping the rear surface of the semiconductor substrate among the first and second conductive wirings, and a protruding portion protruding outside the side surface of the semiconductor substrate in parallel with the second direction, Wherein the first coating layer is located at the protruding portion and the second coating layer is located at the cell portion.

Here, the melting point of the first coating layer may be higher than a first temperature between 160 ° C and 170 ° C, and the melting point of the second coating layer may be lower than the first temperature.

More specifically, the melting point of the first coating layer may be higher than the first temperature and lower than 350 ° C, and the melting point of the second coating layer may be 110 ° C or higher and lower than the first temperature.

In addition, the second coating layer may include SnBiAg, and the first coating layer may include at least one of SnPb, Sn, and Ag.

Further, the thicknesses of the first coating layer and the second coating layer may be equal to each other.

The core may include any one of gold (Au), silver (Ag), copper (Cu), and aluminum (Al).

Here, the first conductive interconnection is connected to the first electrode by a first conductive adhesive at a portion intersecting the first electrode, is insulated from the second electrode by an insulating layer at a portion intersecting the second electrode, The wiring is connected to the second electrode by a first conductive adhesive at a portion intersecting the second electrode and can be insulated from the first electrode by an insulating layer which intersects the first electrode.

Here, the second coating layer positioned in the cell portion in each of the first and second conductive wirings can be connected to the first electrode or the second electrode.

Further, the first coating layer may be located on one side of the surface of the core positioned at the protruding portion, at least on the side facing the inter-cell connector, on the protruding portion of each of the first and second conductive wirings.

Here, the first direction length of the first coating layer positioned at the protruding portion of each of the first and second conductive wirings may be at least larger than the width of the inter-cell connector.

The first coating layer is located on the protruding portion of each of the first and second conductive wires and is located on one surface of the core located on the protruding portion facing the intercell connector and the second coating layer on the opposite surface of the core, Can be located.

The solar cell module according to an exemplary embodiment of the present invention has a structure in which the first coating layer connected to the cell electrode and the second coating layer connected to the inter-cell connector in each of the first and second conductive wirings are made to have different melting points, The physical adhesion of the connector can be further improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view illustrating a plan view of a solar cell module according to an embodiment of the present invention; FIG.
2 is an example of a schematic cross-sectional view of first and second solar cells C1 and C2 connected to each other by an intercell connector 300 adjacent to each other in a first direction (x) in Fig.
FIGS. 3 to 5 are views for specifically explaining the series connection structure of the first and second solar cells C1 and C2 shown in FIG.
6 to 8 are views for explaining an example of a solar cell according to the present invention.
9 is a diagram for explaining the structure of the first and second conductive wirings in the solar cell module according to an example of the present invention in more detail.
10 and 11 are views for explaining an example in which the conductive wiring 200 shown in FIG. 9 is applied to the solar cell module of the present invention.
12 is a view for explaining another example of the conductive wiring 200 in the solar cell module according to an example of the present invention.
13 and 14 are views for explaining an example of a method of forming the conductive wiring 200 according to an example of the present invention.

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 of a certain structure may be a direction toward one surface of the semiconductor substrate to which the direct light is incident, and the rear surface may refer to a surface of the semiconductor substrate on which the direct light is not incident, Lt; / RTI >

Hereinafter, the cell string refers to a structure or a form in which a plurality of solar cells are connected in series to each other.

In addition, the meaning that the thickness and width of a constituent part are the same as the thickness and width of other constituent parts means that they are the same within a range of 10% including a process error.

FIG. 2 is a cross-sectional view of a solar cell module according to an embodiment of the present invention. Referring to FIG. 1, 1 and 2 solar cells (C1, C2).

1 and 2, a solar cell module according to an exemplary embodiment of the present invention includes a plurality of solar cells and a plurality of first and second conductive wirings 200.

In addition, in addition to this, in addition to the above, an inter-cell connector 300 for connecting a plurality of solar cells in series in a first direction x, a front transparent substrate 10 for encapsulating a cell string in which a plurality of solar cells are connected in series, , 30, a back sheet 40, and a frame 50. [

The plurality of solar cells may include a plurality of first electrodes 141 and a plurality of second electrodes 142 on the rear surface of the semiconductor substrate 110 and the semiconductor substrate 110. Such a plurality of solar cells will be described in more detail with reference to FIG.

The plurality of first and second conductive wirings 200 may be connected to the rear surface of each of the plurality of solar cells, as shown in Figs.

As described above, a plurality of solar cells to which the plurality of first and second conductive wirings 200 are connected can be connected in series in the first direction x by the inter-cell connector 300 as shown in Figs. 1 and 2 have.

For example, the intercell connector 300 can connect the first solar cell C1 and the second solar cell C2, which are disposed adjacent to each other in the first direction x of the plurality of solar cells, in series with each other.

2, a plurality of second conductive wirings 220 connected to the front surface of the plurality of first conductive wirings 210 connected to the first solar cell C1 and the second solar cells C2 Can be connected to the rear surface of the inter-cell connector 300, whereby a cell string in which a plurality of solar cells are connected in series can be formed.

As shown in FIG. 2, such a cell string may be thermocompressed and laminated while being disposed between the front transparent substrate 10 and the back sheet 40.

For example, a plurality of solar cells are disposed between the front transparent substrate 10 and the rear sheet 40, and transparent fillers 20 and 30, such as an EVA sheet, are disposed on the front and back surfaces of a plurality of solar cells as a whole , It can be integrated and encapsulated by a lamination process in which heat and pressure are simultaneously applied.

1, the front transparent substrate 10, the back sheet 40, and the fillers 20 and 30 encapsulated by the lamination process can be protected by fixing the edges by the frame 50 .

1, the front transparent substrate 10 and the fillers 20 and 30 are transmitted through the front surface of the solar cell module to form a plurality of solar cells, a plurality of first and second conductive wires 200, The intercell connector 300, the back sheet 40, and the frame 50 can be seen.

In addition, each of the cell strings may be arranged long in the first direction (x) and spaced apart in the second direction (y), and such plurality of cell strings may be arranged in a bushing bar 310 in a second direction (y).

Here, the front transparent substrate 10 may be formed of tempered glass having a high transmittance and excellent breakage-preventing function.

The back sheet 40 can prevent the moisture from penetrating from the rear surface of the solar cells C1 and C2 to protect the solar cell from the external environment. Such a backsheet 40 may have a multi-layer structure, such as a layer preventing moisture and oxygen penetration, a layer preventing chemical corrosion.

Such a backsheet 40 is made of a thin sheet made of an insulating material such as FP (fluoropolymer) / PE (polyeaster) / FP (fluoropolymer), but may be an insulating sheet made of another insulating material.

Such a lamination process may be performed in the state where the planar fillers 20 and 30 are disposed between the front transparent substrate 10 and the solar cell and between the solar cell and the rear substrate.

The materials of the fillers 20 and 30 may be formed of materials different from those of the insulating layer 252 to prevent corrosion due to moisture penetration and to protect the solar cells C1 and C2 from impact. And may be formed of a material such as ethylene vinyl acetate (EVA) capable of absorbing shock.

Therefore, the planar fillers 20 and 30 disposed between the front transparent substrate 10 and the solar cell and between the solar cell and the rear substrate can be softened and cured by heat and pressure during the lamination process.

Hereinafter, in the solar cell module shown in Figs. 1 and 2, a structure in which a plurality of solar cells are connected in series by the first and second conductive wirings 200 and the intercell connectors 300 will be described in more detail.

FIGS. 3 to 5 are views for specifically explaining the series connection structure of the first and second solar cells C1 and C2 shown in FIG.

3 shows an example of a front surface of the first and second solar cells C1 and C2 connected to each other by the inter-cell connector 300 adjacent to each other in the first direction (x) in FIG. 1. FIG. 3 shows an example of the rear surface of the first and second solar cells C1 and C2 shown in Fig. 3 and Fig. 5 shows a cross section along the line X1-X1 in Fig. 3 and Fig.

3 and 4, in the solar cell module according to the present invention, the first and second conductive wirings 200 are formed on the semiconductor substrate 110 provided in the first and second solar cells C1 and C2 Can be connected to the rear surface.

The first and second solar cells C1 and C2 may be arranged at a distance in the first direction x and each of the first and second solar cells C1 and C2 may be at least A plurality of first electrodes 141 formed on the rear surface of the semiconductor substrate 110 and the semiconductor substrate 110 so as to be elongated in a second direction y intersecting the first direction x and spaced apart from each other, Electrode 142 may be provided.

The plurality of first and second conductive wirings 200 are arranged so as to extend in a first direction x in the arrangement direction of the first and second solar cells C1 and C2 and the first and second solar cells C1, C2, respectively.

The plurality of first and second conductive wirings 200 as described above are formed by stacking a plurality of first conductive wires 140 which are crossed and overlapped with the plurality of first electrodes 141 provided in the first and second solar cells C1 and C2, And a plurality of second conductive wirings 220 connected to the wirings 210 and the plurality of second electrodes 142 in a crossing manner.

More specifically, the first conductive wiring 210 is connected to the first electrode 141 provided in each of the plurality of solar cells C1 and C2 through a first conductive adhesive agent 251 made of a conductive material, And may be insulated from the second electrode 142 by an insulating layer 252.

The second conductive wiring 220 is connected to the second electrode 142 provided in each of the plurality of solar cells C1 and C2 through the first conductive adhesive 251 and the insulating layer 252 One electrode 141 can be insulated.

The first and second conductive wirings 200 may be formed of a conductive metal material and may include gold (Au), a conductive core, and a conductive coating layer coating the surface of the core CR.

Here, the coating layer may include a first coating layer and a second coating layer having different melting points along a first direction which is a longitudinal direction of the core. This will be described in more detail with reference to FIG.

One end of the first conductive wiring 210 that is connected to the inter-cell connector 300 includes a protruding portion protruding out of the first side of the semiconductor substrate 110, and the other end of the second conductive wiring 220 One end connected to the inter-cell connector 300 may include a protruding portion protruding from the second side of the semiconductor substrate 110.

Here, the first side and the second side of the semiconductor substrate are located opposite to each other with respect to the semiconductor substrate, and the first and second sides are the lengths of the first and second conductive wirings 210 and 220 And a side in a direction parallel to the second direction intersecting the direction of the first direction.

As a result, the ends of the protruding portions protruding from the projection area of the semiconductor substrate can be connected to the intercell connector 300, and the first and second conductive wirings (210, 220) 210 may be located in the projected area of the semiconductor substrate.

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

Here, the line width of each of the first and second conductive wirings 200 shown in Figs. 4 and 5 is set to be between 0.5 mm and 2.5 mm, while keeping the line resistance of the conductive wirings sufficiently low, And the distance between the first conductive wiring 210 and the second conductive wiring 220 is set to 4 mm so as not to damage the short circuit current of the solar cell module in consideration of the total number of the first and second conductive wiring 200. [ To 6.5 mm.

In this way, the number of the first and second conductive wirings 200 connected to one solar cell can be 10 to 20, respectively. Therefore, the sum of the total number of the first and second conductive wirings 200 connected to one solar cell may be 20 to 40. [

Here, the first conductive adhesive 251 may be formed of a conductive metal. More specifically, the first conductive adhesive 251 may be formed by mixing a part of the metal materials included in the first and second electrodes 141 and 142 Or a mixed layer may be formed together with any one of a solder paste layer and an epoxy solder paste layer.

The first conductive adhesive 251 and the first and second electrodes 251 and 252 are formed so that the first conductive adhesive 251 includes a mixed layer in which some metallic materials included in the first and second electrodes 141 and 142 are mixed, The physical adhesion between the first conductive adhesive agent 251 and the first and second electrodes 141 and 142 can be minimized.

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

The insulating layer 252 may be any insulating material. For example, an insulating material such as epoxy, polyimide, polyethylene, acrylic, or silicone may be used.

One end of each of the plurality of first and second conductive wirings 200 is connected to the inter-cell connector 300, and a plurality of solar cells can be connected in series with each other.

More specifically, the inter-cell connector 300 is located between the first solar cell C1 and the second solar cell C2 and may extend in the second direction y.

3 and 4, when the solar cell is viewed in a plane, the inter-cell connector 300 is electrically connected to the semiconductor substrate 110 of the first solar cell C1 and the semiconductor substrate 110 of the second solar cell C2, And may be disposed apart from the substrate 110.

One end of the first conductive wiring 210 connected to the first electrode 141 of the first solar cell C1 and the second electrode 142 of the second solar cell C2 are connected to the inter- And the first and second solar cells C1 and C2 may be connected in series to each other in the first direction x.

More specifically, as shown in Fig. 5, the first and second solar cells C1 and C2 are arranged in the first direction (x) in a state in which the first and second solar cells C1 and C2 are arranged in the first direction (x) , One string that is extended in the first direction (x) and connected in series by the two conductive wirings (200) and the intercell connector (300) can be formed.

5, one end of each of the first and second conductive wirings 200 overlaps the inter-cell connector 300 and is connected to the inter-cell connector 300 via the second conductive adhesive agent 350. In this case, Can be adhered.

The second conductive adhesive agent 350 for bonding the first and second conductive wires 200 and the intercellular connector 300 to each other is made of a metal material including an alloy containing tin (Sn) or tin (Sn) .

More specifically, the second conductive adhesive agent 350 may have a higher melting point than the first conductive adhesive agent 251 and may include (1) a solder paste containing an alloy containing tin (Sn) or tin (Sn) ), Or (2) an epoxy solder paste or an electrically conductive paste containing an alloy containing tin (Sn) or tin (Sn) in the epoxy.

Since the solar cell module having such a structure is provided with a separate intercell connector 300, the solar cell in which the connection failure occurs between the first and second conductive wirings 200 and the first and second electrodes 200 among the plurality of solar cells When there is a battery, the connection between the intercell connector 300 and the first and second conductive wirings 200 is released, so that the solar cell can be replaced more easily.

Up to now, in the solar cell module according to the present invention, the first and second conductive wirings 200 are connected to the rear surfaces of the first and second solar cells C1 and C2 adjacent to each other, and the first and second solar cells C1, and C2 are connected in series to the inter-cell connector 300. FIG.

However, the solar cell module of the present invention is not limited to the structure in which the first and second solar cells adjacent to each other are necessarily connected in series through the intercell connector 300. In a state where the intercell connector 300 is omitted, The structure in which the first conductive wiring of the battery and the second conductive wiring of the second solar cell overlap each other and are connected to each other through the second conductive adhesive agent 350 is also applicable.

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

6 to 8 are diagrams for explaining an example of a solar cell to which the present invention is applied, FIG. 6 is a partial perspective view showing an example of a solar cell applied to the present invention, and FIG. 7 is a cross- FIG. 8 shows a pattern of the first and second electrodes 200 formed on the rear surface of the semiconductor substrate.

6 and 7, 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 section 121, The passivation layer 190, the plurality of the first electrodes 141, and the plurality of the second electrodes 142. The first electrode 141, the second electrode 142,

Here, the antireflection film 130, the tunnel layer 180, and the passivation layer 190 may be omitted. However, since the efficiency of the solar cell is improved, the following description will be made by way of example.

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. In one example, the semiconductor substrate 110 may be formed of a single crystal silicon wafer.

Here, the impurity of the first conductive type contained in the semiconductor substrate 110 or the impurity of the second conductive type may be any of n-type and p-type conductive types.

When the semiconductor substrate 110 has a p-type conductivity type, impurity of a trivalent element such as boron (B), gallium, indium, or the like is doped in the semiconductor substrate 110. However, when the semiconductor substrate 110 has an 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.

Hereinafter, the case where the impurity contained in the semiconductor substrate 110 is an impurity of the second conductivity type and is n-type will be described as an example. However, the present invention is not limited thereto.

The semiconductor substrate 110 may have a plurality of uneven surfaces on the entire surface thereof. Accordingly, the first semiconductor part 121 located on the front surface of the semiconductor substrate 110 may also have an uneven surface.

Accordingly, the amount of light reflected from the front surface of the semiconductor substrate 110 decreases, and the amount of light incident into the semiconductor substrate 110 increases.

The antireflection film 130 is formed on the front surface of the semiconductor substrate 110 to minimize the reflection of light incident from the outside to the front surface of the semiconductor substrate 110. The antireflection film 130 is formed of an aluminum oxide film (AlOx), a silicon nitride film (SiNx) An oxide film (SiOx), and a silicon oxynitride film (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 can pass carriers generated in the semiconductor substrate 110, as shown in FIGS.

The tunnel layer 180 may pass carriers generated in the semiconductor substrate 110 and passivate the back surface of the semiconductor substrate 110.

In addition, the tunnel layer 180 may be formed of a dielectric material formed of SiCx or SiOx having high durability even at a high temperature process of 600 DEG C or more.

6 and 7, the first semiconductor section 121 may be disposed on the rear surface of the semiconductor substrate 110, for example, in direct contact with a part of the rear surface of the tunnel layer 180 .

The first semiconductor section 121 may be formed of a polycrystalline silicon material having a first conductivity type opposite to the second conductivity type and disposed in the second direction y on the rear surface of the semiconductor substrate 110 .

Here, the first semiconductor section 121 may be doped with an impurity of the first conductivity type, and when the impurity contained in the semiconductor substrate 110 is an impurity of the second conductivity type, The pn junction with the semiconductor substrate 110 can be formed with the layer 180 therebetween.

The first semiconductor section 121 may have a p-type conductivity type and the plurality of first semiconductor sections 121 may be formed of p Impurity of the trivalent element can be doped in the first semiconductor portion 121. [0157]

The second semiconductor section 172 is extended on the rear surface of the semiconductor substrate 110 in a second direction y parallel to the first semiconductor section 121. The second semiconductor section 172 may be formed on the rear surface of the tunnel layer 180, 1 semiconductor region 121. In this case,

The second semiconductor section 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 which is an impurity of the second conductivity type, the plurality of second semiconductor regions 172 may be an n + impurity region.

The second semiconductor section 172 prevents the hole movement toward the second semiconductor section 172, which is the direction of electron movement, by the potential barrier due to the difference in impurity concentration between the semiconductor substrate 110 and the second semiconductor section 172 (E. G., Electrons) to the second semiconductor portion 172 can be facilitated.

Therefore, the amount of charges lost due to the recombination of electrons and holes in the second semiconductor section 172 and the vicinity thereof or the first and second electrodes 200 is reduced and the electron movement is accelerated, The amount of movement can be increased.

6 to 7 illustrate a case where the semiconductor substrate 110 is an impurity of the second conductivity type and the first semiconductor section 121 serves as an emitter section and the second semiconductor section 172 ) Serves as a rear electric field portion.

Alternatively, when the semiconductor substrate 110 contains impurities of the first conductivity type, the first semiconductor portion 121 serves as a rear electric field portion and the second semiconductor portion 172 serves as an emitter portion .

6 and 7, the case where the first semiconductor portion 121 and the second semiconductor portion 172 are formed of a polycrystalline silicon material on the rear surface of the tunnel layer 180 has been described as an example.

Alternatively, if the tunnel layer 180 is omitted, impurities may be diffused in the back surface of the semiconductor substrate 110 and doped in the first semiconductor portion 121 and the second semiconductor portion 172, The first semiconductor part 121 and the second semiconductor part 172 may be formed of the same single crystal silicon material as the semiconductor substrate 110. [

6 to 7, the intrinsic semiconductor part 150 may be formed on the rear surface of the tunnel layer 180 exposed between the first semiconductor part 121 and the second semiconductor part 172, Unlike the first semiconductor part 121 and the second semiconductor part 172, the intrinsic semiconductor part 150 is formed of an intrinsic polycrystalline silicon layer in which impurity of the first conductivity type or impurity of the second conductivity type is not doped .

6 and 7, each of both side surfaces of the intrinsic semiconductor part 150 may have a structure in which the side surfaces of the first semiconductor part 121 and the side surfaces of the second semiconductor part 172 are in direct contact with each other have.

The passivation layer 190 is formed on the back surface of the polycrystalline silicon layer formed on the first semiconductor section 121, the second semiconductor section 172, and the intrinsic semiconductor section 150 by a dangling bond defect So that carriers generated from the semiconductor substrate 110 can be prevented from being recombined by the dangling bonds and disappearing.

8, the plurality of first electrodes 141 may be connected to the first semiconductor portion 121 and may be formed to extend in the second direction y. The first electrode 141 may collect carriers, for example, holes, which have migrated toward the first semiconductor section 121.

The plurality of second electrodes 142 may be connected to the second semiconductor portion 172 and extend in the second direction y in parallel with the first electrode 141. As such, the second electrode 142 can collect carriers, for example, electrons, which have migrated toward the second semiconductor section 172.

The first electrode 141 and the second electrode 142 may be elongated in the second direction y and may be spaced apart from each other in the first direction x. In addition, as shown in FIG. 8, the first electrode 141 and the second electrode 142 may be alternately arranged in the first direction (x).

The holes collected through the first electrode 141 and the electrons collected through the second electrode 142 in the solar cell according to the present invention are used as electric power of the external device through the external circuit device .

The solar cell applied to the solar cell module according to the present invention is not necessarily limited to those shown in FIGS. 6 and 7 except that the first and second electrodes 200 provided in the solar cell are formed only on the rear surface of the semiconductor substrate 110 And other components can be changed at any time.

For example, in the solar cell module of the present invention, a part of the first electrode 141 and the first semiconductor part 121 are located on the front surface of the semiconductor substrate 110, and a part of the first electrode 141 is disposed on the semiconductor substrate 110 The MWT type solar cell may be connected to the remaining part of the first electrode 141 formed on the rear surface of the semiconductor substrate 110 through the hole formed in the semiconductor substrate 110. [

On the other hand, in such a solar cell module, each of the plurality of first and second conductive wirings includes a conductive core and a conductive coating layer that coats the surface of the core, and the conductive coating layer extends along a first direction And may include a first coating layer and a second coating layer having different melting points.

This will be described in more detail as follows.

9 is a diagram for explaining the structure of the first and second conductive wirings in the solar cell module according to an example of the present invention in more detail.

Each of the plurality of first and second conductive wirings 210 and 220 according to the present invention includes a conductive core 201 and a conductive coating layer 230 coating the surface of the core 201 as shown in FIG. .

Here, the core 201 may include any one of gold (Au), silver (Al), copper (Cu), and aluminum (Al).

In addition, the cross-sectional shape of the core 201 may be larger than the width and may be in the form of a metallic ribbon extending in the first direction (x).

The conductive coating layer 230 may include a metal material different from the core 201. The conductive coating layer 230 may include a first coating layer 231 having a different melting point along a first direction x of the core 201, And a second coating layer 232.

The first coating layer 231 may be formed so as to cover the entire surface of the core 201 along the first direction x in the longitudinal direction of the core 201 in the conductive wiring 200, The protrusion 232 may be located at a portion of the end of the core 201 and may be formed to cover the entire surface of the core 201 as shown in Fig.

As described above, the conductive wiring 200 according to the present invention is configured such that the conductive coating layer 230 coated on the surface of the core 201 includes the first coating layer 231 and the second coating layer 232 having different melting points, The coating layers 230 located along the first direction x in the longitudinal direction of the conductive wiring 200 are made to have different melting points so as to more effectively cope with the thermal expansion stress generated in the conductive wiring 200, 200 can be further improved.

Here, the melting point of the first coating layer 231 is made higher than the melting point of the second coating layer 232, so that the physical adhesion between the intercell connector 300 and the conductive wiring 200 can be further improved.

More specifically, the first coating layer 231 may be positioned at the end of each of the conductive wirings 200, and the second coating layer 232 may be located at a remaining portion of each of the conductive wirings 200 except for the ends thereof.

Here, the inter-cell connector 300 may be connected to the first coating layer 231, and the plurality of first electrodes 141 or the plurality of second electrodes 142 may be connected to the second coating layer 232 .

A relatively large thermal expansion stress may be generated in the first direction (x) of the conductive wiring 200 during the heat treatment process in which the conductive wiring 200 is connected to the electrode 140 or the inter-cell connector 300.

In the present invention, the first coating layer 231 having a relatively large melting point is used at the end of the conductive wiring 200, so that the physical adhesion force of the end of the conductive wiring 200, The physical adhesion force of the center portion of the conductive wiring 200, which has a small stress, can be greatly improved.

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

Here, the melting point of the first coating layer 231 may be higher than a first temperature between 160 ° C and 170 ° C, and the melting point of the second coating layer 232 may be lower than the first temperature.

For example, the melting point of the first coating layer 231 may be higher than the first temperature and lower than 350 ° C, and the melting point of the second coating layer 232 may be higher than or equal to 110 ° C and lower than the first temperature.

Here, the first temperature may be a temperature of a heat treatment process in a process of lamination of a solar cell module. For example, the first temperature may be 165 ° C, which is a temperature of a process of laminating a solar cell module.

Thus, for example, the melting point of the first coating layer 231 may be between 110 ° C and 165 ° C, and the melting point of the second coating layer 232 may be between 165 ° C and 350 ° C. , 2 coating layer 230 may be formed.

However, the melting points of the first and second coating layers 230 are not necessarily limited thereto, and the melting points of the first and second coating layers 230 may be different from each other.

For example, the first coating layer 231 may include at least one of SnPb, Sn, and Ag, and the second coating layer 232 may include SnBiAg.

When the first coating layer 231 contains silver (Ag), the core 201 may be formed of any one of gold (Au), copper (Cu), and aluminum (Al) except for silver .

The thicknesses of the first coating layer 231 and the second coating layer 232 may be equal to each other and even if the thicknesses of the first coating layer 231 and the second coating layer 232 are different from each other, Lt; / RTI >

Hereinafter, an example in which the conductive wiring 200 of the present invention including the first and second coating layers 230 having different melting points is applied to the solar cell module will be described.

10 and 11 are views for explaining an example in which the conductive wiring 200 shown in FIG. 9 is applied to the solar cell module of the present invention.

12 is a view for explaining another example of the conductive wiring 200 in the solar cell module according to an example of the present invention.

FIG. 10 is a plan view of a solar cell module to which the conductive wiring 200 of the present invention is applied, and FIG. 11 is a cross-sectional view of a solar cell module to which the conductive wiring 200 of the present invention is applied.

 Each of the plurality of first and second conductive wirings 210 and 220 may include cell portions 210A and 220A and protruding portions 210B and 220B as shown in FIGS.

The protruding portions 210B and 220B of the first and second conductive wirings 210 and 220 are formed so that portions of the first and second conductive wirings 210 and 220 protruding from the first and second sides of the semiconductor substrate 110 And the cell portions 210A and 220A of the first and second conductive wirings 210 and 220 mean a portion where the first and second conductive wirings 210 and 220 and the semiconductor substrate 110 overlap with each other.

Here, the ends of the protruding portions 210B and 220B of the first and second conductive wirings 210 and 220 can be connected to the inter-cell connector 300.

Here, for example, the first coating layer 231 may be located at the protruding portions 210B and 220B, and the second coating layer 232 may be located at the cell portions 210A and 220A.

More specifically, the first coating layer 231 is positioned at the end of the protruding portions 210B and 220B, and the second coating layer 232 is positioned mostly over the cell portions 210A and 220A, 210B, and 220B, respectively.

The second coating layer 232 located in the cell portions 210A and 220A in each of the first and second conductive wirings 210 and 220 can be connected to the first electrode 141 or the second electrode 142, The first coating layer 231 positioned at the ends of the protruding portions 210B and 220B of the first and second conductive wirings 210 and 220 can be connected to the intercell connector 300. [

The first and second conductive wirings 210 and 220 are formed on the rear surface of the semiconductor substrate 110 by a fixing tape (not shown) extending in a second direction y, And can be fixed to the rear surface.

The first and second conductive wirings 210 and 220 are fixed to the respective solar cells by the heat treatment process in a state where the first and second conductive wirings 210 and 220 are fixed to the rear surface of the semiconductor substrate 110 by the fixing tape, , 220 and the inter-cell connector 300 can be connected first.

During the heat treatment process, the second conductive adhesive 350 and the first coating layer 231 of the first and second conductive wirings 210 and 220 are melted to form the first and second conductive wirings 210 and 220 and the inter- 300 may be connected.

The second coating layer 232 of the first and second conductive wirings 210 and 220 and the first and second electrodes 141 and 142 are electrically connected to each other by the first conductive adhesive agent 251 by a heat treatment process during the lamination process As shown in FIG.

Here, the melting point of the first coating layer 231 may be higher than the first temperature, which is the temperature of the heat treatment process in the lamination process, and the melting point of the second coating layer 232 may be higher than the first temperature ≪ / RTI >

Accordingly, the first coating layer 231 is not melted during the lamination process, the first and second conductive wirings 210 and 220 and the inter-cell connector 300 can be maintained in a state of being electrically connected to each other, 2 coating layer 232 and the first conductive adhesive agent 251 are melted so that the first and second conductive wires 210 and 220 and the first and second electrodes 141 and 142 are electrically connected to each other by the first conductive adhesive agent 251 And can be electrically connected.

Here, the first direction length L231 of the first coating layer 231 may be at least greater than the width of the intercell connector 300 and may be smaller than the first direction x length of the protruding portions 210B and 220B.

The first coating layer 231 is located on the protruding portions 210B and 220B of the first and second conductive wirings 210 and 220. The first coating layer 231 is provided on the protruding portions 210B and 220B of the core 201, And may be located on one side facing the intercell connector 300.

11, the first coating layer 231 is located on the protruding portions 210B and 220B of the first and second conductive wirings 210 and 220, and the first coating layer 231 is formed on the protruding portions 210B and 220B. And may be located on the rear surface of the core 201 as well as the front surface facing the intercell connector 300 of the surface of the positioned core 201. [

However, the present invention is not limited thereto, and the first coating layer 231 may be disposed on only one side of the surface of the core 201 located at the protruding portions 210B and 220B, facing the intercell connector 300.

12, the first coating layer 231 in the protruding portions 210B and 220B of each of the first and second conductive wirings 210 and 220 may be formed in the shape of a core (not shown) located at the protruding portions 210B and 220B. The second coating layer 232 is located on the front surface of the core 201 facing the intercell connector 300 and on the rear surface opposite to the front surface of the core 201 located in the protrusions 210B and 220B It is possible.

As described above, the first and second conductive wirings 210 and 220 are formed by locating the first coating layer 231 having a relatively high melting point on the protruding portions 210B and 220B of the first and second conductive wirings 210 and 220, 220 and the intercell connector 300 are improved and the first and second conductive wirings 210 and 220 are heated even after the module process or module manufacturing is completed, It is possible to prevent disconnection between the first and second conductive wirings 210 and 220 and the inter-cell connector 300 due to the thermal expansion stress of the first and second conductive wirings 210 and 220.

Hereinafter, an example of a method of manufacturing the conductive wiring 200 having the first and second coating layers 230 on the surface of the core 201 will be described.

13 and 14 are views for explaining an example of a method of forming the conductive wiring 200 according to an example of the present invention.

The method of manufacturing the conductive wiring 200 according to the present invention may be various.

For example, in order to form the conductive wiring 200, the second coating layer 232 may be coated on the surface of the metal core 201 as shown in FIG. 13 (a).

13B, one side of the first region S1 located at the end of the conductive wiring 200 may be removed. Here, the second coating layer 232 located on one side of the first region S1 may be removed by physical etching or chemical visualization.

13 (c), the first coating layer 231 may be formed in the first region S1 to form the conductive interconnection 200. Next, as shown in Fig.

13 illustrates a method of coating the first coating layer 231 on the first region S1 after removing the second coating layer 232 from the first region S1 located at the end of the conductive wiring 200 The conductive wiring 200 of the present invention may be formed by selectively coating the first coating layer 231 on the first region S1 and the second coating layer 232 on the second region S2.

Although the method of forming the first coating layer 231 in the first region S1 located at the end of the metal core 201 in the state where the metal core 201 is previously cut is described as an example in FIG 13, The second coating layer 232 is first applied to the second region S2 of the metal core 201 in a state in which the metal core 201 is arranged long in the first direction x as shown in (a) of FIG. 14 And then the first coating layer 231 is formed in the first region S1 located in the middle rather than the end of the metal core 201 as shown in Fig. 14 (b) 1 It is also possible to form the conductive wiring 200 of the present invention by cutting the boundary line CL between the coating layer 231 and the second coating layer 232.

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, Of the right.

Claims (15)

A plurality of solar cells arranged in a first direction and connected to each other in series and each having a semiconductor substrate and a plurality of first and second electrodes arranged on the rear surface of the semiconductor substrate in a second direction crossing the first direction, ; And
A plurality of first conductive wirings arranged in the first direction on the rear surface of the semiconductor substrate of each of the plurality of solar cells and connected to the plurality of first electrodes and a plurality of first conductive wirings connected to the plurality of second electrodes, 2 conductive wiring;
A plurality of first conductive wirings connected to the first solar cell and a plurality of second conductive wirings arranged in the second direction between first and second solar cells disposed adjacent to each other of the plurality of solar cells, And an inter-cell connector to which the plurality of second conductive wirings connected are commonly connected,
Each of the plurality of first and second conductive wirings includes a conductive core and a first coating layer coated on the surface of the core and connected to the intercell connector and a second coating layer connected to the first and second electrodes,
Wherein a melting point of the first coating layer is higher than a melting point of the second coating layer.
delete The method according to claim 1,
Wherein the first coating layer is positioned at an end of each of the plurality of first and second conductive wirings,
Wherein the second coating layer is located at a remaining portion of each of the plurality of first and second conductive wirings except the ends thereof. The method according to claim 1,
Each of the plurality of first and second conductive wirings
A cell portion overlapping the rear surface of the semiconductor substrate among the first and second conductive wirings;
And a protruding portion protruding out of a side surface of the semiconductor substrate in parallel with the second direction and connected to the intercell connector,
Wherein the first coating layer is located at the protruding portion and the second coating layer is located at the cell portion. The method according to claim 1,
Wherein the melting point of the first coating layer is higher than a first temperature between 160 ° C and 170 ° C,
And the melting point of the second coating layer is lower than the first temperature. 6. The method of claim 5,
Wherein a melting point of the first coating layer is higher than the first temperature and lower than or equal to 350 ° C. 6. The method of claim 5,
And the second coating layer has a melting point of 110 ° C or higher and the first temperature or lower. The method according to claim 1,
Wherein the second coating layer comprises SnBiAg,
Wherein the first coating layer comprises at least one of SnPb, Sn, and Ag. The method according to claim 1,
Wherein the first coating layer and the second coating layer have the same thickness. The method according to claim 1,
Wherein the core comprises any one of gold (Au), silver (Ag), copper (Cu), and aluminum (Al). The method according to claim 1,
Wherein the first conductive wiring is connected to the first electrode by a first conductive adhesive at a portion intersecting the first electrode and is insulated from the second electrode by an insulating layer at a portion intersecting the second electrode,
Wherein the second conductive wiring is connected to the second electrode by the first conductive adhesive at a portion intersecting with the second electrode and is insulated from the first electrode by the insulating layer intersecting the first electrode Battery module. 5. The method of claim 4,
And the second coating layer located in the cell portion in each of the first and second conductive wirings is connected to the first electrode or the second electrode. 13. The method of claim 12,
Wherein the first coating layer is located on one side of the surface of the core located at the protruding portion of each of the first and second conductive wirings and facing at least the inter-cell connector. 13. The method of claim 12,
Wherein the first directional length of the first coating layer located at the protruding portion of each of the first and second conductive wirings is at least larger than the width of the inter-cell connector. 14. The method of claim 13,
Wherein the first coating layer is located on a projecting portion of each of the first and second conductive wirings and is located on one surface of the surface of the core located at the protruding portion facing the inter-cell connector, And the second coating layer is located.

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