KR101542003B1 - Solar cell module - Google Patents

Abstract

The present invention relates to a solar cell module. The solar cell module according to the present invention includes: a semiconductor substrate; a first and a second electrode formed to be apart from each other on the rear surface of the semiconductor substrate; a plurality of solar cells disposed close to each other; an interconnector electrically connecting the solar cells in series. In each of the solar cells, the first electrode includes a plurality of first finger electrodes and a first bus bar electrode to which the finger electrodes are commonly connected. The second electrode includes second finger electrodes apart from the first finger electrodes and a second bus bar electrode to which the second finger electrodes are commonly connected. An interconnector is overlapped with and connected to the first finger electrodes and the second finger electrodes but is not overlapped with the first and second bus bars.

Description

Solar cell module {SOLAR CELL MODULE}

The present invention relates to a solar cell module.

A typical solar cell has a substrate made of different conductivity type semiconductors, such as p-type and n-type, an emitter, and an electrode connected to the substrate and the emitter, respectively. At this time, a p-n junction is formed at the interface between the substrate and the emitter.

The solar cell using the semiconductor substrate can be divided into various types such as a conventional type and a rear type depending on the structure.

In the conventional type, the emitter portion is located on the front surface of the substrate, the electrode connected to the emitter portion is disposed on the front surface of the substrate, the electrode connected to the substrate is positioned on the rear surface of the substrate, And all of the electrodes are located on the rear surface of the substrate.

Since the electrodes of the rear contact type solar cell are all formed on the rear surface of the substrate, the electrodes formed on the rear surface of the substrate are connected in series to the electrodes of the adjacent solar cells via the interconnector or another conductive metal to form the solar cell module .

The present invention relates to a solar cell module.

A solar cell module according to the present invention includes a plurality of solar cells arranged adjacent to each other and including a first electrode and a second electrode spaced apart from each other on a rear surface of a semiconductor substrate and a semiconductor substrate; And an interconnector electrically connecting the plurality of solar cells to each other in series. In each of the plurality of solar cells, the first electrode includes a plurality of first finger electrodes and a plurality of first finger electrodes, Wherein the second electrode includes a second finger electrode spaced apart from the first finger electrode and a second bus bar electrode having electrodes commonly connected to the second finger electrode, Finger electrodes or a plurality of second finger electrodes, and are not overlapped with the first and second bus bar electrodes.

Here, in each of the plurality of solar cells, each of the first and second finger electrodes is elongated in the first direction, and each of the first and second bus bar electrodes extends in a second direction intersecting the plurality of first and second finger electrodes And the plurality of solar cells are arranged apart from each other in the second direction, and the interconnector can be elongated in the second direction.

At this time, the interconnector may have a conductive ribbon or a conductive wire form.

In a specific example, when a plurality of solar cells include first, second, and third solar cells arranged in sequence, the interconnector includes a first interconnector and a second interconnector, The first electrode of the battery and the second electrode of the first solar cell may be connected in series and the second interconnector may connect the second electrode of the second solar cell and the first electrode of the third solar cell in series.

At this time, between the first interconnector and the first electrode of the second solar cell, and between the second interconnector and the second electrode of the second solar cell are connected to each other by a conductive adhesive, and the first interconnector and the second solar cell And between the second electrodes and between the second interconnector and the first electrode of the second solar cell can be insulated from each other by an insulating layer.

In addition, the width of the portion of the first and second finger electrodes of each of the plurality of solar cells connected to the interconnector may be larger than the width of the portion not connected to the interconnector.

As described above, the solar cell module according to the present invention minimizes thermal stress stress between the first and second finger electrodes and the first and second bus bars by connecting the interconnectors to the first and second finger electrodes located on the rear surface of the solar cell. And the banding of the semiconductor substrate can be minimized.

1 and 2 are views for explaining an example of a solar cell module according to the present invention.
FIGS. 3 and 4 are views for explaining an example of a solar cell structure applicable to the solar cell module shown in FIGS. 1 and 2. FIG.
5 is a view for explaining another example of the first and second electrodes C141 and C142 in the solar cell according to the present invention.
6 is a view for explaining an example of the interconnector (IC) shown in Fig.

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

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

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

FIG. 1 is a rear view of a solar cell module according to the present invention. FIG. 2 is a cross-sectional view taken along line CS1-CS1 of FIG. 1, and FIG. It is the appearance.

As shown in FIG. 1, the solar cell module according to the present invention may include a plurality of solar cells C1 to C3 and an interconnector (IC).

Here, each of the plurality of solar cells C1 to C3 may be spaced apart from each other and arranged in the second direction y. For example, as shown in FIG. 1, the first, second and third solar cells C1, C2 and C3 may be arranged apart from each other in the second direction y.

Each of the plurality of solar cells C1 to C3 includes a semiconductor substrate 110 on which a pn junction is formed, a first electrode C141 and a second electrode C142 formed on the rear surface of the semiconductor substrate 110, can do.

The first electrode C141 included in each of the plurality of solar cells C1 to C3 includes a plurality of first finger electrodes F141 and a first bus bar electrode B141.

The plurality of first finger electrodes F141 extend in a first direction x and the first bus bar electrode B141 extends in a second direction y intersecting the plurality of first finger electrodes F141. And a plurality of first finger electrodes F141 may be connected in common.

A plurality of second finger electrodes F142 and a plurality of second bus bar electrodes B142 of the second electrode C142 included in each of the plurality of solar cells C1 to C3 are included.

The plurality of second finger electrodes F142 extend in a first direction x and the second bus bar electrode B142 extends in a second direction y intersecting the plurality of second finger electrodes F142. And a plurality of second finger electrodes F142 may be connected in common.

Here, the width of each of the first and second bus bar electrodes B141 and B142 may be greater than the width of each of the first and second finger electrodes F141 and F142.

The interconnector (IC) serves to electrically connect a plurality of solar cells (C1 to C3) to each other in series. 1, the interconnector IC is formed on the back surface of the semiconductor substrate 110 of each solar cell in a second direction (y) intersecting with a plurality of first and second finger electrodes F141 and F142, And may be extended to be connected to the first electrode C141 or the second electrode C142.

Specifically, the interconnector (IC) may include a first interconnector IC1 and a second interconnector IC2.

1 and 2, a plurality of solar cells C1 to C3 including first, second, and third solar cells C1, C2, and C3 are sequentially arranged in a second direction y, The first interconnection IC1 is connected in series with the first electrode C141 of the second solar cell and the second electrode C142 of the first solar cell, The second electrode C142 of the second solar cell and the first electrode C141 of the third solar cell may be connected in series.

Here, the electrical connection between the first and second electrodes C141 and C142 of each solar cell and the interconnector (IC) can be connected to each other by the conductive adhesive CP.

For example, as shown in Fig. 2, the first interconnector IC1 and the first electrode C141 of the second solar cell and the second interconnector IC2 and the second electrode C142 of the second solar cell ) Can be connected to each other by a conductive adhesive (CP).

The first interconnector IC1 may be connected to the second electrode C142 of the first solar cell by a conductive adhesive CP and the second interconnector IC2 may be connected to the second electrode of the first solar cell by a conductive adhesive CP. 3 solar cell C141.

Here, the conductive adhesive CP is not particularly limited as long as it is a conductive material, but a conductive material having a melting point at a relatively low temperature of 140 ° C to 180 ° C is more preferable. However, the melting point is not necessarily limited to this, and the melting point may vary.

For example, the conductive adhesive CP may be a solder paste or a conductive material such as a conductive paste or a conductive adhesive film in which the conductive metal particles are contained in the insulating resin, or the like.

In addition, the interconnector (IC) may be provided in the form of a conductive ribbon or a conductive wire. When the interconnector (IC) is provided in the form of a conductive ribbon or a conductive wire, the manufacturing process of the solar cell module is simple and the material cost is low, thereby further reducing the manufacturing cost of the solar cell module.

Such an interconnector (IC) may be formed of a material having good conductivity such as copper (Cu) or silver (Ag).

In addition, electrical insulation between the first and second electrodes C141 and C142 of each solar cell and the interconnector IC can be performed by the insulating layer IP.

An insulating layer IP is formed between the first interconnector IC1 and the second electrode C142 of the second solar cell and between the second interconnector IC2 and the first electrode C141 of the second solar cell. Respectively.

The first interconnection IC1 and the first electrode C141 of the first solar cell and the second interconnector IC2 and the second electrode C142 of the third solar cell are also connected to the insulating layer IP As shown in Fig.

Here, the insulating layer IP may be formed of an insulating resin such as epoxy.

At this time, the interconnector (IC) is not connected to the first bus bar electrode B141 or the second bus bar electrode B142 of each solar cell in a superimposed manner, but a plurality of first finger electrodes F141, The first and second bus bar electrodes B141 and B142 may be overlapped and connected to the two finger electrodes F142 and not overlapped with the first and second bus bar electrodes B141 and B142.

1, a region overlapping the interconnector (IC) at the rear surface of the semiconductor substrate 110 may be spaced apart from the region where the first and second bus bars are located and the distance between D1 and D2 . For example, the region where the first bus bar is located and the region where the first interconnector IC1 is overlapped can be separated by D1, and the region where the second bus bar is located and the region where the second interconnector IC2 is overlapped D2. ≪ / RTI >

As described above, the interconnection IC is not connected to the first bus bar electrode B141 or the second bus bar electrode B142 of each solar cell in a superimposed manner, but a plurality of first finger electrodes F141 or a plurality of By forming the solar cell module so as to be overlapped with the second finger electrode F142, defectiveness of the solar cell module can be improved and banding of the semiconductor substrate 110 can be minimized to improve the efficiency of the solar cell.

More specifically, when the interconnector IC is connected to the first and second bus bar electrodes B141 and B142 of each solar cell, the interconnection IC is connected to each solar cell a plurality of first and second finger electrodes (B141 and B142) commonly connected to the first and second bus bar electrodes (B141 and B142) are arranged on the first and second bus bar electrodes (B141 and B142) F141, and F142 may be disconnected to cause failure of the solar cell module.

The reason why the disconnection can occur between the first and second bus bar electrodes B141 and B142 and the first and second finger electrodes F141 and F142 is that the first and second bus bar electrodes B141 and B142 Heat is applied to the entire surface along the longitudinal direction of the first and second bus bar electrodes B141 and B142 so that the first and second bus bars B141 and B142 are electrically connected to each other, The lengths of the electrodes B141 and B142 can contract along the second direction y.

At this time, the contraction lengths of the first and second bus bar electrodes B141 and B142 may increase as the length and width of the first and second bus bar electrodes B141 and B142 increase.

Therefore, the first and second finger electrodes F141 and F142 are subjected to extreme thermal expansion stress at the connection points of the first and second finger electrodes F141 and F142 and the first and second bus bar electrodes B141 and B142, And the first and second bus bar electrodes B141 and B142.

In addition, the semiconductor substrate 110 may be excessively bent according to longitudinal shrinkage of the first and second bus bar electrodes B141 and B142. Therefore, if the shrink length of the first and second bus bar electrodes B141 and B142 is excessively large, the semiconductor substrate 110 may be damaged and the carrier lifetime of the semiconductor substrate 110 may be significantly reduced Thus, the efficiency of the solar cell can be remarkably reduced.

However, as in the present invention, the interconnection IC is superimposed and connected to the plurality of first finger electrodes F141 or the plurality of second finger electrodes F142, the first and second bus bar electrodes B141 and B142, The disconnection between the first and second bus bar electrodes B141 and B142 and the plurality of first and second finger electrodes F141 and F142 can be minimized, Can be minimized.

More specifically, since each of the first and second finger electrodes F141 and F142 is connected in a direction crossing the interconnector IC, a plurality of first and second finger electrodes F141 and F142, Can be minimized.

In addition, the plurality of first and second finger electrodes F141 and F142 may have a relatively small width and may have a relatively smaller shrink length than the first and second bus bar electrodes B141 and B142.

Therefore, the thermal expansion stress occurring at the connection point between the first and second finger electrodes F141 and F142 and the first and second bus bar electrodes B141 and B142 can be further mitigated.

Even if a part of the plurality of first and second finger electrodes F141 and F142 is disconnected from the connection point between the first and second finger electrodes F141 and F142 and the first and second bus bar electrodes B141 and B142 And the first and second finger electrodes F141 and F142 which are partially disconnected are already connected to the interconnector IC and the remaining first and second finger electrodes F141 and F142 are connected to the first and second bus bar electrodes B141, and B142) provide a bypass path, thereby further improving the current collection efficiency of the solar cell.

In addition, since the shrink length of the first and second finger electrodes F141 and F142 is relatively small, bending of the semiconductor substrate 110 can be minimized.

Accordingly, efficiency reduction of each solar cell can be minimized, and efficiency reduction of the solar cell module as a whole can be minimized.

Although the overall structure of the solar cell module has been described so far, a solar cell applicable to the solar cell module will be described below.

FIGS. 3 and 4 are views for explaining an example of a solar cell structure applicable to the solar cell module shown in FIGS. 1 and 2. FIG.

Referring to FIG. 3, an example of a solar cell according to the present invention includes a semiconductor substrate 110, an antireflection film 130, an emitter 121, a back surface field (BSF) 172, (C141) and a second electrode (C142).

Here, the antireflection film 130 and the backside electrical part 172 may be omitted. Hereinafter, the antireflection film 130 and the backside electrical part 172 will be described with reference to FIG. 3 as an example.

The semiconductor substrate 110 may be a semiconductor substrate 110 of a first conductivity type, for example, n-type conductivity type silicon. The semiconductor substrate 110 may be formed by doping a first conductivity type impurity into a semiconductor wafer formed of a crystalline silicon material.

The emitter portions 121 are spaced apart from each other on the rear surface of the semiconductor substrate 110 facing the front surface, and extend in a direction parallel to each other. The plurality of emitter portions 121 may include a second conductive type, for example, a p-type conductive type impurity opposite to the conductive type of the semiconductor substrate 110. [

Accordingly, a p-n junction can be formed by the semiconductor substrate 110 and the emitter section 121.

A plurality of the rear electric components 172 may be disposed on the rear surface of the semiconductor substrate 110 and are spaced apart from each other in a direction parallel to the plurality of emitter portions 121 and extend in the same direction as the plurality of emitter portions 121 . Accordingly, as shown in FIG. 3, a plurality of emitter portions 121 and a plurality of rear electric sections 172 may be alternately arranged on the rear surface of the semiconductor substrate 110.

The plurality of rear electric field sections 172 may be an impurity having the same conductivity type as the semiconductor substrate 110 and containing impurities at a higher concentration than the semiconductor substrate 110, for example, an n ++ part.

The first electrode C141 may include a plurality of first finger electrodes F141 and a first bus bar electrode B141 as described above with reference to FIGS.

The plurality of first finger electrodes F141 may be physically and electrically connected to the emitter section 121 and may be formed on the back surface of the semiconductor substrate 110 along the emitter section 121, (X) intersecting the first bus bar electrode B141 as shown in FIG.

In addition, the second electrode C142 may include a plurality of second finger electrodes F142 and a second bus bar electrode B142 as described above with reference to FIGS.

The plurality of second finger electrodes F142 are formed on the rear surface of the semiconductor substrate 110 along the plurality of rear electric units 172 and electrically connected to the semiconductor substrate 110 through the rear electric part 172, And may be connected and disposed in a first direction (x) intersecting the second bus bar electrode B142, as shown in FIG.

Here, on the rear surface of the semiconductor substrate 110, the first electrode C141 and the second electrode C142 may be physically and spatially separated from each other and electrically isolated as shown in FIG.

Here, the widths W1a and W2a of the first and second finger electrodes F141 and F142 may be between 200um and 500um.

The holes collected through the first electrode (C141) and the electrons collected through the second electrode (C142) in the solar cell according to the present invention manufactured using the above structure 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 FIG. 3 or 4, and the first and second electrodes C141 and C142 (C141 and C142) Other components can be changed at any time, except that they are formed only on the rear side.

4 shows a case where the widths W1a and W2a of the first and second finger electrodes F141 and F142 are constant. Alternatively, the interconnector IC may include first and second finger electrodes F141 and F142, In order to lower the contact resistance between the interconnector IC and the first and second finger electrodes F141 and F142 and to further improve the adhesive force, the first and second finger electrodes F141 and F142, , And F142, the width of the portion overlapping the interconnector (IC) can be made larger than the width of the remaining portion.

5 is a view for explaining another example of the first and second electrodes C141 and C142 in the solar cell according to the present invention.

In Fig. 5, the first interconnection IC1 may be connected to the AIC1 region, and the second interconnection IC2 may be connected to the AIC2 region.

5, the first and second finger electrodes F141 and F142 of the solar cell according to the present invention are formed such that the width of a portion connected to the interconnector IC does not reach the interconnector IC The width may be larger than the width.

The width W1a of the portion where the first interconnector IC1 and the first finger electrode F141 overlap each other is set to the remaining portion (i.e., the first interconnector IC1 and the first finger electrode F141) The width W2a of the portion where the second inter connecter IC2 and the second finger electrode F142 are overlapped and connected to each other can be made larger than the width W1b of the remaining portion (The portion where the second interconnection IC2 and the second finger electrode F142 do not overlap) can be made larger than the width W2b.

Here, for example, the width of a portion overlapping with the first interconnection IC1 or the second interconnection IC2 for connecting to each interconnection IC in each of the first and second finger electrodes F141 and F142 W1b, and W2b may be 1.2 times to 3 times larger than the widths W1a and W2a of the portion not connected to each interconnection IC.

This is because when the interconnectors (IC) are connected to the first and second finger electrodes F141 and F142 having relatively small widths, the area of the region where the first and second finger electrodes F141 and F142 overlap each other is relatively small, 5, when the width of the portion overlapping the interconnector (IC) in the first and second finger electrodes F141 and F142 is made larger than the width of the remaining portion, The contact resistance between the electrodes C141 and C142 can be relatively lowered and the physical force to which the interconnector IC is bonded to the first and second electrodes C141 and C142 can be further increased.

Accordingly, it is possible to minimize defects and deterioration of the solar cell module due to weakening of the adhesive force between the interconnector (IC) and the first and second electrodes C141 and C142.

6 is a view for explaining an example of the interconnector (IC) shown in Fig.

The interconnection IC according to the present invention may be a conductive ribbon IC-A or a conductive wire IC-B shown in Fig. 6B.

As shown in Fig. 6A, the conductive ribbon IC-A may have a rectangular cross section, and the conductive wire IC-B may have a cylindrical shape having a cross section of a radius R have.

Here, the conductive ribbon IC-A and the conductive wire IC-B may be formed by coating the surface of the conductive metal core 310 with an adhesive metal material 320.

The conductive metal core 310 may be made of a conductive metal such as copper, silver or gold. The adhesive metal 320 may be formed of a conductive metal material A metal material such as tin (Sn) having a relatively low melting point may be used.

In addition, when the conductive ribbon IC-A is used as an inter-connector IC, the width of the ribbon IC-A does not connect to the inter-connector IC at the first and second finger electrodes F141 and F142 The width of the portion (WIC-A) of the ribbon (IC-A) may be between 0.5 mm and 2 mm.

In addition, when the conductive wire IC-B is used as an interconnection IC, the width WIC-B of the wire IC-B is smaller than the width WIC-B of the first and second finger electrodes F141 and F142, ) And 10% within the error range. In one example, the width (WIC-B) of the wire (IC-B) may be between 200 um and 500 um.

It will be apparent to those skilled in the art that various modifications, substitutions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. will be. Therefore, the embodiments disclosed in the present invention and the accompanying drawings are intended to illustrate and not to limit the technical spirit of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments and the accompanying drawings . The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

Claims (7)

1. A solar cell comprising: a plurality of solar cells each including a semiconductor substrate and a first electrode and a second electrode spaced apart from each other on a rear surface of the semiconductor substrate and disposed adjacent to each other; And
And an interconnector electrically connecting the plurality of solar cells to each other in series,
In each of the plurality of solar cells, the first electrode includes a plurality of first finger electrodes and a first bus bar electrode to which the plurality of first finger electrodes are commonly connected, A second finger electrode spaced apart from the first finger electrode, and a second bus bar electrode having electrodes commonly connected to the second finger electrode,
Wherein the interconnector is connected to the plurality of first finger electrodes or the plurality of second finger electrodes in a superimposed manner,
The first and second bus bar electrodes are not overlapped with each other,
Wherein the interconnector is connected to the plurality of first finger electrodes or the plurality of second finger electrodes through a conductive adhesive having a melting point between 140 캜 and 180 캜 and is spaced apart from the first and second bus bar electrodes by a predetermined interval The solar cell module being located. The method according to claim 1,
In each of the plurality of solar cells, each of the plurality of first and second finger electrodes extends in the first direction,
Wherein each of the first and second bus bar electrodes extends in a second direction intersecting with the first and second finger electrodes,
Wherein each of the plurality of solar cells is arranged apart from each other in the second direction,
And the interconnector extends in the second direction. The method according to claim 1,
The interconnector has a conductive ribbon or a conductive wire form. The method according to claim 1,
The plurality of solar cells include first, second, and third solar cells sequentially arranged,
Wherein the inter connecter includes a first inter connecter and a second inter connecter,
Wherein the first inter connecter connects the first electrode of the second solar cell and the second electrode of the first solar cell in series,
And the second interconnector connects the second electrode of the second solar cell and the first electrode of the third solar cell in series. 5. The method of claim 4,
The first interconnector and the first electrode of the second solar cell and the second interconnector and the second electrode of the second solar cell are connected to each other by the conductive adhesive. 5. The method of claim 4,
And between the first interconnector and the second electrode of the second solar cell and between the second interconnector and the first electrode of the second solar cell are insulated from each other by an insulating layer. The method according to claim 1,
Wherein a width of a portion of the first and second finger electrodes of each of the plurality of solar cells connected to the interconnector is greater than a width of a portion of the first and second finger electrodes that is not connected to the interconnector.

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