KR101816151B1 - Solar cell module - Google Patents

Abstract

The present invention relates to a solar cell module. The solar cell module according to an exemplary embodiment of the present invention comprises: a plurality of solar cells arranged in a first direction to be connected in series to one another and each including a semiconductor substrate, and a plurality of first electrodes and a plurality of second electrodes lengthily disposed in a second direction crossing the first direction on a back surface of the semiconductor substrate; a plurality of first conductive lines connected to the first electrodes and a plurality of second conductive lines connected to the second electrodes, the first and second conductive lines lengthily disposed in the first direction on the back surface of the semiconductor substrate of each of the solar cells; and an inter-cell connector which is lengthily disposed in the second direction between first and second solar cells adjacent to each other among the solar cells, and to which the first conductive lines connected to the first solar cell and the second conductive lines connected to the second solar cell are commonly connected, wherein each of the first and second conductive lines includes a conductive core and a conductive coating layer for coating the front surface among surfaces of the conductive core connected to the first and second electrodes, and the back surface, which is opposite from the front surface, is different from the front surface.

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- .

In the case where the metal wiring is connected to the rear surface of the solar cell, if the solar cell module is operated in the field after the completion of the solar cell module, the solar cell module may be affected by the season, , It can be exposed to an environment in which the high temperature and the low temperature are continuously repeated.

At this time, high temperature and low temperature are repeated in the inside of the solar cell module, so that the metal wiring is thermally expanded or heat shrinked, so that the metal wiring and the electrode of the solar cell are disconnected or the physical adhesion force between the metal wiring and the inter- The inter-cell connector may be bent.

An object of the present invention is to provide a solar cell module with improved reliability by suppressing thermal expansion or heat shrinkage of a metal wiring that may be caused by an exposed external environment during operation of the 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, Each of the first and second conductive wirings including a conductive core and a conductive coating layer for coating a surface of the core which is connected to the plurality of first and second electrodes, The rear surface of the core is different from the front surface of the core.

Here, the rear surface of the core may include a first region where the conductive coating layer is not located, unlike the front surface of the core.

In addition, the solar cell module includes a front transparent substrate located on the front surface of a plurality of solar cells; A front filler positioned between the front transparent substrate and the plurality of solar cells; And

 A rear substrate positioned on a rear surface of the plurality of solar cells; And a rear filler positioned between the rear substrate and the plurality of solar cells.

Here, the conductive coating layer is entirely coated on the front surface connected to the first and second electrodes in the core included in each of the first and second conductive wirings, and the first region is positioned at both ends of the core in the first direction .

Here, the first region overlaps the edge regions of both ends of the semiconductor substrate in the first direction, and the conductive coating layer may be coated on the rear surface of the core except for the first region.

Here, of the back surfaces of the cores contained in the first and second conductive wirings, the length of overlapping the first region with the edge region of the semiconductor substrate may be between 5 mm and 20 mm.

In addition, the rear surface of the core exposed in the first region may have a plurality of irregularities.

Here, the back filler may be in direct physical contact with the backside of the core exposed in the first region.

Alternatively, the insulating coating layer may be further disposed on the rear surface of the core exposed to the first region, and the insulating coating layer may physically contact the rear filler material.

Also, the first region may be located on the entire rear surface of the core.

In addition, the entire backside of the core can be in direct physical contact with the back filler.

Alternatively, an insulating coating layer may be further formed on the entire rear surface of the core exposed to the first region, and the insulating coating layer may physically contact the rear filler.

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, 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 intercell connector may be spaced apart from the semiconductor substrate of each of the first and second solar cells.

The core may be formed of at least one of gold (Au), silver (Al), copper (Cu), and aluminum (Al), and the conductive coating layer may include at least one of SnBiAg, SnPb, Sn, have.

The insulating coating layer may be an epoxy-based polymer.

In the front surface of the conductive core included in the first conductive wiring, the conductive coating layer is selectively coated only on a region connected to the first electrode and a region connected to the inter-cell connector, The coating layer may be selectively coated only on a region connected to the second electrode and on an area connected to the inter-cell connector.

The solar cell module according to an embodiment of the present invention has a first region where the conductive coating layer is not located on at least a part of the rear surface of the core among the conductive wirings including the core and the conductive coating layer so that thermal expansion and heat shrinkage of the conductive wirings can be suppressed have.

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.
10 is a view schematically showing the first embodiment in which the first region is provided on a part of the rear surface of the conductive wiring.
11 is a cross-sectional view taken along the line X2-X2 in Fig.
12 is a view showing an example in which the module shown in FIG. 11 is modularized between a front transparent substrate and a rear substrate.
FIG. 13 is a diagram for explaining a first modification of the first area shown in FIG. 10; FIG.
FIG. 14 is a diagram for explaining a second modification of the first area shown in FIG. 10; FIG.
15 is a view for explaining a second embodiment in which the first region is provided on the entire rear surface of the conductive wiring.
16 is a diagram for explaining a modification to the second embodiment.

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, a plurality of first and second conductive wirings 200, and an intercell connector 300.

In addition, in addition to this, it is possible to further include a front transparent substrate 10, front and back fillers 20 and 30, a back substrate 40, and a frame 50 that encapsulate a cell string in which a plurality of solar cells are connected in series to each other have.

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, the cell string may be thermocompressed and laminated while being disposed between the front transparent substrate 10 and the rear substrate 40.

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

1, the front transparent substrate 10, the rear substrate 40, and the front and back fillers 20 and 30 encapsulated by the lamination process are fixed at the edges by the frame 50, .

1, the front transparent substrate 10 and the front filler 20 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 wirings 200, The connector 300, the rear substrate 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 rear substrate 40 can prevent moisture from penetrating from the rear surface of the solar cells C1 and C2, thereby protecting the solar cell from the external environment. Such a backside substrate 40 may have a multi-layer structure, such as a layer preventing moisture and oxygen penetration, a layer preventing chemical corrosion.

The rear substrate 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.

In this lamination process, the front filler 20 is positioned between the front transparent substrate 10 and the solar cell, and the back filler 30 is positioned between the solar cell and the rear substrate 40.

The materials of the front and rear fillers 20 and 30 may be formed of a thermosetting material to prevent corrosion due to moisture penetration and to protect the solar cells C1 and C2 from impact and absorb shock And may be formed of a material such as ethylene vinyl acetate (EVA).

Accordingly, the sheet-like front and back fillers 20, 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 at each of the plurality of solar cells C1 and C2 through the first conductive adhesive 251 made of a conductive material And may be insulated at a portion intersecting the second electrode 142 by an insulating layer 252 made of an insulating material.

The second conductive wiring 220 is connected to the second electrode 142 provided at each of the plurality of solar cells C1 and C2 through the first conductive adhesive 251. The insulating layer 252 The first electrode 141 may be insulated at a portion where it intersects the first electrode 141.

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. [

In this solar cell module, in order to suppress thermal expansion or heat shrinkage of the conductive wiring, which may be caused by the exposed external environment during operation of the solar cell module, And may include a first region.

This will be described in more detail as follows.

9 is a view for explaining the structure of the first and second conductive wirings 210 and 220 in the solar cell module according to an example of the present invention in more detail.

4, each of the first and second conductive wirings 210 and 220 according to an embodiment of the present invention includes a conductive core 201 and a conductive coating layer 202 for coating the surface of the core 201, . ≪ / RTI >

Here, the core 201 may be a metal formed of at least 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) (x).

In addition, the conductive coating layer 202 may be coated on the entire front and side surfaces of the core 201.

The conductive coating layer 202 may be entirely coated on the front surface of the core 201 included in each of the first and second conductive wirings 210 and 220 connected to the first and second electrodes 141 and 142.

In addition, a first region 200RA where the conductive coating layer 202 is not formed may be formed on at least a part of the rear surface of the core 201. [

9, the first region 200RA where the conductive coating layer 202 is not located is positioned at both ends of the core 201 in the first direction x of the core 201 , And the rear surface of the core 201 positioned at both ends in the first direction (x).

In addition, the conductive coating layer 202 may be coated on the rear surface of the core 201 except for both ends in the first direction (x).

Here, the conductive coating layer 202 may include at least one of SnBiAg, SnPb, Sn, and Ag.

The conductive wiring in which the first region 200RA where the conductive coating layer 202 is not formed is formed on the rear surface of the core 201 as described above can be applied as shown in FIGS. 10 and 11 below.

10 is a view schematically showing the first embodiment in which the first region 200RA is provided on a part of the rear surface of the conductive wiring, Fig. 11 is a view showing a cross section taken along the line X2-X2 in Fig. 10, 11 shows an example in which the module shown in FIG. 11 is modularized between a front transparent substrate and a rear substrate.

10, the first and second electrodes 141 and 142, the conductive adhesive, and the insulating layer are not shown for the sake of understanding.

11, a conductive coating layer 202 is formed on the front surface of the core 201 included in each of the first and second conductive wirings 210 and 220 and connected to the first and second electrodes 141 and 142, Can be coated as a whole.

The first region 200RA where the conductive coating layer 202 is not located and the rear surface of the core 201 is exposed is positioned at both ends of the core 201 in the first direction x of the core 201 10, the first region 200RA may be overlapped with the edge regions S1 at both ends of the semiconductor substrate 110 in the first direction (x).

10 and 11, the conductive coating layer 202 may be coated on the rear surface of the core 201 except for the first region 200RA formed at both ends in the first direction x. have.

10 and 11, the length OL of the first region 200RA overlapping the edge region S1 of the semiconductor substrate 110 may be between 5 mm and 20 mm.

The first region 200RA is positioned at both ends of the first and second conductive wirings 210 and 220 in the first direction x so that the first region 200RA overlaps the edge region S1 of the semiconductor substrate 110 It is possible to more effectively reduce the thermal expansion stress that is relatively larger at both ends in the longitudinal direction of the first and second conductive wirings 210 and 220.

12, the rear surface of the core 201 exposed in the first region 200RA of the first and second conductive wirings 210 and 220 is electrically connected to the rear filler 30 ). ≪ / RTI >

Thus, the rear surface of the core 201 exposed in the first region 200RA of the first and second conductive wirings 210 and 220 is physically in direct contact with the rear filler 30, so that the first and second conductive wirings 210, and 220, respectively.

More specifically, the back filler 30 according to the present invention may be formed of a thermosetting material as described above. After the thermosetting material is once cured, it is not softened even when heat is applied again .

The material coated on the surface of the core 201 of the first and second conductive wirings 210 and 220 is mainly a solder material. Such a solder material is relatively ductile as compared with the core 201, There is a characteristic that the thermal deformation easily occurs.

When the temperature inside the module rises due to the external environment during module operation, the first and second conductive wirings 210 and 220 are subjected to thermal expansion stress in the longitudinal direction, and the first and second conductive wirings 210 and 220 The thermal expansion coefficient of both ends of the first direction (x) in the longitudinal direction may be relatively large.

However, when the rear surface of the core 201 is physically brought into direct contact with the rear filler 30 of the hardenable material at both ends of the first and second conductive wirings 210 and 220 in the first direction (x) The thermal expansion stress of the first and second conductive wirings 210 and 220 to be expanded in the longitudinal direction is reduced by the rear filler 30 so that the first and second conductive wirings 210 and 220 ) Can be reduced.

A modification of the first region 200RA capable of more effectively reducing the coefficient of thermal expansion of the first and second conductive wirings 210 and 220 will be described below.

13 is a view for explaining a first modification of the first area 200RA shown in Fig. 10, and Fig. 14 is a view for explaining a second modification of the first area 200RA shown in Fig. 10 Respectively.

13, in the first modification of the first region 200RA, a plurality of irregularities 200P may be provided on the rear surface of the core 201 exposed in the first region 200RA.

13, the first region 200RA is located at both ends of the rear surface of the core 201 included in the first and second conductive wirings 210 and 220 in the first direction x, A plurality of irregularities 200P may be provided on the portion of the core 201 where the first region 200RA is formed.

Thus, the surface area at which the core 201 and the back filler 30 are physically bonded can be increased at both ends of the rear surface of the core 201 in the first direction (x), and the first and second conductive wires 210 , 220 can be further reduced.

14, in the second modification of the first region 200RA, the insulating coating layer 200L is further disposed on the rear surface of the core 201 exposed in the first region 200RA, and the insulating coating layer 200L may physically contact the rear filler 30 directly.

Here, the insulating coating layer 200L may be an epoxy-based polymer or a thermosetting material.

The insulating coating layer 200L can further improve the adhesion with the rear filler 30 and further reduce the thermal expansion coefficient of the first and second conductive wirings 210 and 220.

In this case, the first and second conductive wirings 210 and 220 may be formed in the same manner as the first and second conductive wirings 210 and 220. In this case, The coefficient of thermal expansion of the thermoplastic resin can be further reduced.

Although the first and second conductive wirings 210 and 220 include the first region 200RA at both ends of the rear surface of the core 201 in the first direction x as an example, The first region 200RA may be formed in the entire rear region of the core 201 included in the first and second conductive wirings 210 and 220. [

This will be described in more detail as follows.

FIG. 15 is a view for explaining a second embodiment in which the first region 200RA is provided on the entire rear surface of the conductive wiring, and FIG. 16 is a diagram for explaining a modification to the second embodiment.

15, the first region 200RA according to the second embodiment is disposed entirely on the rear surface of the core 201 in each of the first and second conductive wirings 210 and 220, The entire rear surface of the semiconductor device can be exposed.

Thus, the entire rear surface of the core 201 can be in direct physical contact with the back filler 30. [

16, in the modification of the second embodiment, an insulating coating layer 200L is further formed on the first region 200RA formed on the entire rear surface of the core 201, The insulating coating layer 200L formed on the entire surface can be in direct physical contact with the rear filler 30. [

As described above, the first and second conductive wirings 210 and 220 according to the second embodiment of the present invention have the first region 200RA formed on the entire rear surface of the core 201, and the first and second conductive wirings 210 , 220 can be further reduced.

In each of the above-described embodiments, the case where the conductive coating layer 202 is formed on the entire front surface of the core 201 in each of the cores 201 included in the first and second conductive wirings 210 and 220 is explained The conductive coating layer 202 may be selectively formed only in a region where the conductive coating layer 202 is connected to the first and second electrodes 141 and 142 in the front surface of the core 201 and in an area connected to the intercell connector 300.

That is, the conductive coating layer 202 of the front surface of the conductive core 201 included in the first conductive wiring 210 is selectively coated with only the region connected to the first electrode 141 and the region connected to the inter- .

The conductive coating layer 202 may be selectively coated on only a region connected to the second electrode 142 and a region connected to the inter-cell connector 300, .

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 (17)

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, An inter-cell connector to which the plurality of second conductive wirings connected are commonly connected;
A front transparent substrate disposed on a front surface of the plurality of solar cells; And
And a rear substrate disposed on a rear surface of the plurality of solar cells,
Wherein each of the first and second conductive wirings includes a conductive core and a conductive coating layer for coating the surface of the core,
Wherein the conductive coating layer is provided on a front surface of the core facing the front transparent substrate to connect to the plurality of first and second electrodes,
And a first region of the surface of the core facing the rear substrate, the conductive region being different from the front surface of the core.
delete The method according to claim 1,
The solar cell module
A front filler positioned between the front transparent substrate and the plurality of solar cells; And
And a rear filler disposed between the rear substrate and the plurality of solar cells. The method of claim 3,
Wherein the conductive coating layer is entirely coated on the front surface of the core included in each of the first and second conductive wirings and connected to the first and second electrodes,
Wherein the first region is located at both ends of the core in the first direction from the rear side of the core. 5. The method of claim 4,
Wherein the first region overlaps with a rim region at both ends of the semiconductor substrate in the first direction,
Wherein the conductive coating layer is coated on the rear surface of the core except for the first region. 6. The method of claim 5,
Out of the rear surface of the core included in each of the first and second conductive wirings,
Wherein a length of the first region overlapping the edge region of the semiconductor substrate is between 5 mm and 20 mm. 6. The method of claim 5,
Wherein a back surface of the core exposed in the first region has a plurality of projections and depressions. The method of claim 3,
Wherein the back filler is in direct physical contact with the back surface of the core exposed in the first region. 9. The method of claim 8,
Wherein an insulating coating layer is further disposed on a rear surface of the core exposed in the first region,
Wherein the insulating coating layer is in direct physical contact with the back filler. The method of claim 3,
Wherein the first region is located on the entire rear surface of the core. 11. The method of claim 10,
Wherein the entire backside of the core is in direct physical contact with the back filler. 11. The method of claim 10,
An insulating coating layer is further formed on the entire rear surface of the core exposed in the first region,
Wherein the insulating coating layer is in direct physical contact with the back filler. 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. 14. The method of claim 13,
And the intercell connector is spaced apart from the semiconductor substrate of each of the first and second solar cells. The method according to claim 1,
Wherein the core is formed of at least one of gold (Au), silver (Al), copper (Cu), and aluminum (Al)
Wherein the conductive coating layer includes at least one of SnBiAg, SnPb, Sn, and Ag. 10. The method of claim 9,
Wherein the insulating coating layer is an epoxy-based polymer. The method according to claim 1,
The conductive coating layer is selectively coated only on a region connected to the first electrode and a region connected to the inter-cell connector among the entire surface of the conductive core included in the first conductive wiring,
Wherein the conductive coating layer is selectively coated only on a region connected to the second electrode and an area connected to the inter-cell connector among the entire surface of the conductive core included in the second conductive wiring.

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