KR102219791B1 - Solar cell module - Google Patents

Abstract

In one preferred embodiment, the solar cell module includes a solar cell including a front electrode formed on the front surface of a semiconductor substrate, a rear electrode formed on the rear surface of the semiconductor substrate as an interface, and a solar cell adjacent to the front electrode. A wiring member connected to the rear electrode, a plurality of front pad portions formed at an intersection point where the front electrode and the wiring member cross, and a plurality of rear pad portions formed at an intersection point where the rear electrode and the wiring member cross, the The rear electric field portion is formed only to correspond to each of all rear electrodes formed on the rear surface of the semiconductor substrate, and the number of the rear pad portions is less than the number of the front pad portions.

Description

Solar cell module {SOLAR CELL MODULE}

The present invention relates to a solar cell module with improved efficiency.

A solar cell has a semiconductor substrate forming a pn junction, an emitter, a rear electric field layer, and an electrode connected to the semiconductor substrate with the emitter/rear electric field at an interface. The solar cell constructed in this way constitutes a solar cell module by electrically connecting neighboring solar cells with an inter-connector having a size of about 1.5mm. In general, three interconnectors are used to connect two adjacent solar cells.

The process of connecting the inter-connector to the solar cell is also referred to as a tabbing process. In general, the inter-connector is soldered to an electrode. For tabbing, the solar cell contains bus electrodes with a width of about 1.5 (mm).

Since this bus electrode is made of silver (Ag), which is the same material as the finger electrode that collects electric charges, it acts as a cause of increasing the manufacturing cost of the solar cell from the perspective of the producer.

In addition, if there are multiple inter-connectors with a line width of around 1.5 (mm) on the front of the solar cell to which light is incident, the light-receiving surface is reduced, and a partial shaded area is formed due to the inter-connector, reducing the efficiency of the solar cell. have.

The present invention is invented in the context of such a technical background, and is to provide a solar cell module that improves the above-described problems.

In one preferred embodiment, the solar cell module includes a solar cell including a front electrode formed on the front surface of a semiconductor substrate, a rear electrode formed on the rear surface of the semiconductor substrate as an interface, and a solar cell adjacent to the front electrode. A wiring member connected to the rear electrode, a plurality of front pad portions formed at an intersection point where the front electrode and the wiring member cross, and a plurality of rear pad portions formed at an intersection point where the rear electrode and the wiring member cross, the The rear electric field portion is formed only to correspond to each of all rear electrodes formed on the rear surface of the semiconductor substrate, and the number of the rear pad portions is less than the number of the front pad portions.

The ratio (m/n) of the number of rear pad parts (m) to the number of front pad parts (n) is 0.5≦1 <1.

The pitch of the rear pad portion is greater than the pitch of the front pad portion, and the number of intersections between the rear pad portion and the rear pad portion immediately adjacent thereto is the number of intersection points between the front pad portion and the front pad portion immediately adjacent thereto. More than the number.

The rear pad portion and the front pad portion are disposed at equal intervals, respectively, in the extending direction of the wiring member.

The size of the front pad part is the same as the size of the rear pad part.

The pitch of the front electrode is equal to or greater than the pitch of the rear electrode, and the line width of the rear electrode is equal to or greater than the line width of the front electrode.

The number of lines of the rear electrode is greater than the number of lines of the front electrode.

The wiring member has a wire shape having a diameter of 200 (um)-500 (um), and 10 to 15 or less wiring members connect two adjacent solar cells.

It further includes a reflector coupled to the wiring member between the solar cell and the solar cell adjacent thereto.

The reflector is made of the same material as the front electrode or the rear electrode, or made of the same material as the wiring material.

The reflector is coupled to the front and rear surfaces, respectively, with the wiring member interposed therebetween.

The surface of the reflector includes irregularities, or enters inward from the end of the solar cell and is combined with the wiring member.

The reflector is soldered to the entire wiring material.

According to an embodiment of the present invention, since the rear pad portion can be formed less than that of the front pad portion, manufacturing cost can be reduced.

In addition, light-receiving efficiency can be improved by using a wire-shaped wiring member having a thin line width instead of a wiring member having a wide line width previously used.

In addition, since the reflector is formed between the solar cell and the solar cell, light-receiving efficiency can be increased due to the light reflected from the reflector.

The drawings attached to this specification show schematics for easy explanation of the invention. Therefore, the accompanying drawings may be different from the actual one.
1 is a view showing the overall appearance of a solar cell module.
FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1.
3 is a cross-sectional view taken along the line BB of FIG. 1.
4 shows the overall appearance of the wiring material.
5 is a diagram showing an arrangement relationship between a front electrode and a wiring member.
6 is a diagram showing an arrangement relationship between a rear electrode and a wiring member.
7 to 10 are views for explaining an arrangement relationship between a front pad portion and a rear pad portion.
11 is a view showing a reflector.
12 to 17 are cross-sectional views taken along the CC line of FIG. 11 and show various aspects of the reflector.

The examples described below are only a preferred form and do not represent all of the present invention. In particular, the embodiments made by selectively selecting and selecting each of the constituent elements described through the embodiments below, and combining them, also belong to the present invention because each constituent element has already been described.

In addition, embodiments of the present invention will be described in detail below with reference to the drawings. In the description, the same reference numerals are assigned to the same or substantial portions of the drawings, and the description is not repeated to avoid duplication of description.

In addition, the numerical ranges presented below are only examples, and the numerical ranges presented below may be adjusted due to various variables unless there is a specific limitation.

Hereinafter, a solar cell module according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4. 1 is a perspective view showing the overall appearance of a solar cell module, FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1, FIG. 3 is a cross-sectional view taken along line B-B of FIG. 1, and FIG. 4 is a view of a wiring member.

1 to 4, in the solar cell module of this embodiment, a plurality of wiring members 125 having a thin thickness are connected to a plurality of solar cells disposed adjacent to each other. The wiring material 125 is electrically connected (hereinafter, connected) to the front electrode 113 formed on the front surface of the first solar cell C1 among two adjacent solar cells, and is also adjacent to the first solar cell C1. It is connected to the rear electrode C2 formed on the rear surface of the second solar cell C2.

In this embodiment, it will be described that the solar cell has a bifacial structure that absorbs light from the front and rear surfaces of the semiconductor substrate 111, respectively.

The solar cell has a cube shape with a thin thickness, the width and length are approximately 156 (mm) * 156 (mm), and the thickness is 150 (um)-200 (um).

A front electrode 113 is positioned on the front surface of which light is incident, and is connected to the wiring material 125 through the front pad unit 140. The front electrode 113 collects electric charges opposite to that of the semiconductor substrate 111. In one example, if the semiconductor substrate 111 is a p-type semiconductor substrate, the front electrode 113 collects electrons.

The semiconductor substrate 111 forms a pn junction and is formed of an n-type or p-type semiconductor substrate including first conductive impurities.

A rear electrode 115 having a shape similar to that of the front electrode 113 is positioned on the rear surface of the semiconductor substrate 111 and is connected to the wiring material 125 through the rear pad unit 160. The rear electrode 115 collects a conductive charge opposite to that of the front electrode 113.

The front electrode 113 and the rear electrode 115 will be described in detail below with different drawings.

And, between the rear electrode 115 and the semiconductor substrate 111, a rear electric field portion () is located, and the rear electric field portion 154 contains impurities having the same conductivity as the semiconductor substrate 111 at a higher concentration than the substrate 111. As a doped region, it is formed locally only to correspond to the rear electrode 115.

The rear electric field 154 is of the same conductivity type as the substrate, and if the semiconductor substrate 111 is n-type, the rear electric field 154 is also n-type, and is formed by implanting phosphorus (P) as an impurity on the rear surface of the substrate. I can. In a preferred form, the rear electric field unit 154 can be formed locally by implanting impurities into the rear surface of the substrate by ion implanting, which is one of the ion implantation methods.

The rear electric field 154 prevents the recombination of different charges on the surface of the substrate by forming a potential barrier due to the difference in impurity concentration from the substrate 111, thereby preventing the transfer of charges having the same polarity as the substrate toward the rear surface. can do.

In this embodiment, it is described that the rear electric field part 154 is not formed on the entire rear surface of the substrate, but is formed only on some electrodes, but differently, the rear electric field unit 154 is formed on the entire rear surface of the semiconductor substrate 111 It is also possible to be formed.

In a solar cell having such a configuration, two adjacent solar cells are connected by a wiring member 125.

The wiring member 125 has a wire shape as illustrated in FIG. 4A. In FIG. 4 (B) shows a cross-sectional shape of the wiring member 125.

As shown, the wiring material 125 has a cross-sectional shape in which the coating layer 125a coats the core layer 125b with a thin thickness (around 12 (um)), and a total thickness of 250 (um)-550 (um) Has.

The core layer 125b is a metal material having good conductivity such as Ni, Cu, Ag, and Al having good conductivity, and the coating layer 125b has a chemical formula such as Pb, Sn or SnIn, SnBi, SnPb, Sn, SnCuAg, and SnCu. Since it contains a metallic material, especially solder, soldering is possible.

When connecting two adjacent solar cells, 10 to 15 wiring members 125 are used when the semiconductor substrate has a size of 156 (mm) * 156 (mm), and the size of the substrate or the line width and thickness of the electrode , Pitch, and thickness of wiring materials are adjusted as variables.

The above description is based on the fact that the wiring member 125 is a wire shape having a circular cross section, but may have various shapes such as a rectangle and an oval cross section.

Such wiring material 125 connects two adjacent solar cells, one side is connected to the front electrode 113 through the front pad part 140 of the first solar cell C1, and the other side is connected to the second solar cell. It is connected to the rear electrode 115 through the rear pad part 1600 of the battery C2. One preferred form of connecting the electrode and the wiring material is soldering in which the material is melted and bonded, or conductive synthetic resin with adhesive strength. Conductive adhesives containing particles are also possible.

In this embodiment, the front pad portion 140 and the rear pad portion 160 are further positioned as points where the front electrode 113 and the wiring member 125 cross each other. Such pads 140 and 160 expand the area where the front electrode 113 and the wiring material 125, and the rear electrode 115 and the wiring material 125 intersect, so that the wiring material 125 is connected to the front electrode 113 and the rear electrode. When each is connected to 115, the contact resistance is reduced, and the bonding force between the wiring material 125 and the electrodes 113 and 115 is increased.

An example of a soldering method is to position the wiring material 125 on the front and rear surfaces of two adjacent solar cells, respectively, so that the wiring material 125 faces the front electrode 113 and the rear electrode 115, respectively, and is in this state. The coating layer 125a of the wiring member 125 is heated above the melting temperature for several seconds. Accordingly, as the coating layer 125a is melted and cooled, the wiring material 125 is attached to the electrode.

In this embodiment, a reflector 170 is further positioned between the solar cell and the solar cell. In the longitudinal direction of the wiring member 125, the solar cell is separated by a certain distance from the adjacent solar cell, so that an inter section IA exists between the solar cell and the solar cell. The reflector 170 is located in the inter section IA and scatters light incident on the inter section IA so that the light is incident to neighboring solar cells.

Hereinafter, the front electrode 113 of the solar cell module configured as described above will be described in more detail with reference to FIG. 5.

In this embodiment, the front electrode 113 includes a collection electrode 1131 and a connection electrode 1133.

The collection electrode 1131 has a constant line width and extends long in one direction, for example, in a direction crossing the extension direction of the wiring member 125, and is arranged parallel to the neighboring one to form a stripe arrangement. The collection electrode 1131 has a line width of 35 (um)-70 (um), and the pitch Pf, which is a distance between the electrode and the electrode, is 1.3 (mm)-1.8 (mm). The numerical range presented here is only a preferred example, and the numerical range is adjusted according to various variables.

The connection electrode 1133 also has a constant line width and extends long in a direction crossing the collection electrode 1131, that is, in the same direction as the extension direction of the wiring member 125, thereby electrically connecting the collection electrode 1131.

The connection electrode 1133 has a line width of 35 (um)-70 (um), substantially the same as the collection electrode 1131, but the pitch Bdf is 9 (mm)-13 (mm). Greater than (1131).

Alternatively, the connection electrode 1133 may have a larger line width than the collection electrode 1131, and may be equal to or smaller than the horizontal width wfh of the front pad unit 140.

Since the connection electrode 1133 having such a configuration is not a necessary configuration, it is also possible that the front electrode 113 is composed of only the collection electrode 1131 without the connection electrode 1133. As the connection electrode 1133 is omitted, the area to which light is incident can be increased, and the manufacturer can reduce the material cost to reduce the production cost.

In addition, a front pad portion 140 is selectively formed at a point where the collection electrode 1131 and the connection electrode 1133 intersect. The vertical width (wfv) of the front pad part 140 is 300-500 (um), and the horizontal width (wfh) is 800 (um)-1.2 (mm).

In a preferred form, the front pad portion 140 is formed at every intersection point, but there are 13-20 front pad portions 140 based on one line of the connection electrode 1133 under conditions such as manufacturing cost and efficiency. They are arranged at equal intervals. In the drawing, in the extending direction of the connection electrode 1133, it is exemplified that the front pad portion 140 is formed at an intersection for every 2*n (n=natural number) line.

In addition, the front pad portion 140 is preferably formed at all intersections in the extending direction of the collection electrode 1131.

Therefore, when there are 100 connection electrodes 1131 and 12 collection electrodes 1133, the total number of pads formed on the front surface is 50*12.

The collection electrode 1131, the connection electrode 1133, and the front pad portion 140 may be simultaneously formed by a screen printing method, and in this case, they are all made of the same material, for example silver (Ag). In addition, each component can be configured separately as needed.

In addition, the wiring member 125 is positioned directly above the connection electrode 1133 and is formed long in a direction parallel to the connection electrode. Accordingly, the wiring material 125 and the connection electrode 1133 are arranged to face each other. The line width Da of the wiring member 125 is 200 (um)-700 (um), which is smaller than the horizontal width wfh of the front pad portion 140.

Since the wiring material 125 is soldered while being disposed on the connection electrode 1133 as described above, it is melt-coupled not only with the front pad unit 140 but also with the connection electrode 1133, thereby reducing the contact resistance between the electrode and the wiring material. The efficiency of the solar cell can be increased, and the bonding strength of wiring materials can also be increased.

Hereinafter, the rear electrode 115 will be described in detail with reference to FIG. 6.

In this embodiment, the rear electrode 115 also includes a collection electrode 1151 and a connection electrode 1153 like the front electrode 113. In the following description, so as not to be confused with the front electrode 113, the collection electrode 1131 and the connection electrode 1133 of the front electrode 113 are referred to as a front collection electrode 1131 and a front connection electrode 1133, respectively, and The collection electrode 1151 of the electrode 115 is called a rear collection electrode, and the connection electrode 1153 is called a rear connection electrode.

The rear collecting electrode 1151 has a constant line width and extends long in one direction, for example, in a direction crossing the extension direction of the wiring member 125 to have a strip shape, and is arranged in parallel with neighboring ones to form a stripe arrangement.

The rear collecting electrode 1151 has a line width of 35 (um)-70 (um) and a pitch Pb of 1.4 (mm)-1.7 (mm), similar to the front collecting electrode 1131. In another preferred form, the rear collecting electrode 1151 has a larger line width than the front collecting electrode 1131 and has a line width of 75 (um)-115 (um), and the pitch Pb is 1.4 (mm), the same as the front collecting electrode 1131 )-1.7(mm).

In this way, it is also possible to configure the collection electrode 1151 on the rear surface to be thicker than the collection electrode 1131 on the front surface.

In addition, the front side has a large series resistance of about 120 -140 (Ω/sq), while the rear side is about 20 -40 (Ω/sq), which is lower than the front. Therefore, in order to increase the contact area with the wiring material, the front collecting electrode 113 requires a relatively larger number of pad portions than the rear surface, and as a result, the pitch of the front collecting electrode 1131 becomes larger than the rear surface, and the rear collecting electrode 1151 The number of) may be greater than that of the front collection electrode 1131.

Meanwhile, in the drawing, it is shown that the line widths of the front collecting electrode 1131 and the rear collecting electrode 1151 are the same.

In addition, the rear connection electrode 1153 also has a constant line width, and extends long in a direction crossing the rear collection electrode 1151, that is, in the same direction as the extension direction of the wiring material 125 to electrically connect the rear collection electrode 1151 I'm making it.

The rear connection electrode 1153 has a line width of 35 (um)-70 (um), the same as the rear collection electrode 1151, and the pitch (Bdb) is 9 (mm)-13 (mm) the same as the front surface. Is the pitch (Bdb) of

Alternatively, the rear connection electrode 1153 may have a larger line width than the rear collection electrode 1151 and may be equal to or smaller than the width wbh of the rear pad unit 160.

Since the rear connection electrode 1153 is not necessarily a necessary configuration, the rear electrode 115 may also be composed only of the collection electrode 1151. As the rear connection electrode 1153 is omitted, the area in which light is incident can be increased, and the manufacturer can reduce the material cost to reduce the manufacturing cost.

In addition, a rear pad part 140 is selectively formed at a point where the rear collection electrode 1151 and the rear connection electrode 1153 intersect, so that the rear electrode 115 can be connected to the wiring material 125. . In this embodiment, the size of the rear pad unit 160 is the same as the front pad unit 140, the vertical width (wbv) is 300-500 (um), the horizontal width (wbh) is 800 (um)-1.2 (mm), but can be configured in other sizes optionally.

In this embodiment, the rear pad portion 160 is formed in a smaller number than the front pad portion 140. In the drawing, it is exemplified that the number of rear pad portions 160 is 1/2 than that of the front pad portion 140.

As illustrated in the drawing, the rear electrode 115 has a locally formed rear electric field part 154 corresponding to the collection electrode 1151. The rear electric field 154 is a region doped with impurities at a higher concentration than the semiconductor substrate 111. For example, if the impurity concentration of the semiconductor substrate 111 is 1*1016 (atoms/cm3), the rear electric field 154 is It is doped with a high concentration of 2*1020 (atoms/cm3).

In this embodiment, since the rear electric field part 154 is formed locally only for the collection electrode 1151, the rear electric field part 154 is also separated from a neighboring one like the collection electrode 1151 by a certain distance. To achieve.

As such, the rear surface of the semiconductor substrate 111 is formed with a collection electrode 1151 through the interface of the rear electric field 154 doped with a high concentration, so when measured with a measuring device, the rear side series resistance is 20-40 (Ω/ sq), while the front is 120-140 (Ω/sq), which is about three times larger than this.

This fact disproves that the contact resistance between the wiring member 125 and the electrode is much larger on the front surface than on the rear surface. As a result of the experiment conducted by the present inventor, it was found that even if the number of the rear pad portions 160 is reduced to the front pad portion 140 * 1/2, the efficiency of the solar cell is not affected. However, when the number of the rear pad portions 160 is smaller than 1/2 of the front pad portions 140, the efficiency of the solar cell was found to decrease rapidly.

In this embodiment, the number of rear pad portions 160 is configured to be less than that of the front pad portion 140, thereby effectively reducing manufacturing cost and maintaining the efficiency of the solar cell.

The rear collecting electrode 1151, the rear connecting electrode 1153, and the rear pad unit 160 may be formed simultaneously by a screen printing method, and in this case, they are all made of the same material, for example silver (Ag). In addition, each component can be configured separately as needed.

In addition, the wiring material 125 is positioned directly above the rear connection electrode 1153 and is formed elongated in a direction parallel to the rear connection electrode 1153, and the pitch of the wiring material is substantially equal to the pitch Bdb of the connection electrode 1153 same.

In the rear side as well, since soldering is performed while the wiring material 125 is disposed on the rear connection electrode 1153 as described above, even if the number of the rear pad portions 160 is relatively smaller than the number of the front pad portions 140, the wiring material Since 125 is melt-coupled not only with the rear pad unit 160 but also with the rear connection electrode 1153 in the longitudinal direction, the contact resistance between the electrode and the wiring material is reduced, and the bonding strength of the wiring material is also increased.

As described above, in this embodiment, since the rear pad unit 160 is formed less than the front pad unit 140, the positions of the front pad unit 140 and the rear pad unit 160 are located at the positions of the front electrode and the rear electrode. According to the various arrangements. This will be described in detail with reference to FIGS. 7 to 10.

In these drawings, only the components necessary for explanation are shown briefly, the dashed-dotted line represents the front collecting electrode 1131, the dotted line represents the rear collecting electrode 1151, and the dashed-dotted line represents the wiring material 125. In addition, it is assumed that the wiring member 125 is positioned on the same line at the front and the rear, and the sizes of the front pad 140 and the rear pad 160 are the same.

First, FIG. 7 shows a case where the front collecting electrode 1131 and the rear collecting electrode 1151 have the same pitch, and the front collecting electrode 1131 and the rear collecting electrode 1151 are located on the same line.

The front pad portion 140 is formed every multiple of 2, and there is one intersection point without the front pad portion 140 in the extending direction of the wiring member 125. In addition, the rear pad portion 160 is formed every multiple of 4, and there are three intersection points without the rear pad portion 160 therebetween. As a result, the pitch Pdf, which is the distance between the front pad portions 140, is smaller than the pitch Pdb of the rear pad portions 160.

On the other hand, the rear pad portion 160 is formed in a multiple of 4, whereas the front pad portion 140 is formed in a multiple of 2, so when the front pad portion 140 and the rear pad portion 160 overlap, all rear pads The portion 160 is positioned to overlap the front pad portion, and one front pad portion 140 is positioned between the rear pad portion 160.

In comparison, FIG. 8 shows that the front collecting electrode 1131 and the rear collecting electrode 1151 are located on the same line as in FIG. 7, but the rear pad unit 160 does not overlap the front pad unit 140. , It shows a state formed between the front pad portion 140. In this case, the front pad portion 140 is formed in a multiple of 2, and the rear pad portion 160 is formed in a multiple of 4, so all the rear pad portions 160 are not in a position overlapping with the front pad portion 140. .

9 shows a case where the pitches of the front collection electrode 1131 and the rear collection electrode 1151 are the same, but the front collection electrode 1131 and the rear collection electrode 1151 are not positioned on the same line.

In this case, the front collecting electrode 1131 and the rear collecting electrode 1151 are not located on the same line in the extending direction of the wiring member 125, but are alternately arranged. Further, the front pad portion 140 is formed in a multiple of 2, and the rear pad portion 160 is formed in a multiple of 4, so that the front pad portion 140 and the rear pad portion 160 are not in an overlapping position.

10 shows a case where the pitch of the front collecting electrode 1131 is larger than the pitch of the rear collecting electrode 1151. In this case, since the pitch of the rear collecting electrode 1151 is smaller than the pitch of the front collecting electrode 1131, the front collecting electrode 1131 and the rear collecting electrode 1151 are located on the same line, adjacent to each other, or far away. It has various shapes, such as being separated.

Accordingly, the rear pad unit 160 includes all cases where the rear pad unit 160 is positioned at an overlapping position with the front pad unit 140, positioned at a position that only partially overlaps, or positioned at another position.

Hereinafter, the reflector 170 will be described with reference to FIGS. 11 to 16. 11 is a view for explaining a reflector, a plan view centered on the inter section IA, and FIG. 12 is a cross-sectional view taken along line C-C of FIG. 11.

The second solar cell c2 is separated by an inter section IA and is connected to the first solar cell c1 and the wiring member 125. In addition, the reflector 170 is positioned as the inter section IA.

In this embodiment, the reflector 170 is a bar-shaped rectangular parallelepiped and made of a metal material having good reflectivity. For example, the reflector 170 is made of the same material as the electrodes 113 and 115 or the same material as the wiring material 125.

The reflector 170 is fixed to the wiring member 125 and is soldered to the wiring member 125 in a preferred form. In this case, when the wiring material 125 is soldered to the electrodes 113 and 115, since the wiring material 125 is also soldered with the reflector 170, the manufacturing cost can be reduced by reducing the number of work hours.

Preferably, the reflector 170 is connected to all wiring members 170 connecting the two solar cells. In this embodiment, as for the wiring member 125, twelve wiring members are used to electrically connect the two solar cells c1 and c2, and the reflector 170 is soldered with all 12 wiring members.

On the other hand, one side of the wiring member 125 is connected to the front electrode 113 of the first solar cell c1, and the other side is connected to the rear electrode 115 of the second solar cell c2. Accordingly, the wiring member 125 is inclined at a predetermined angle in the inter section IA, and the reflector 170 fixed to the wiring member 125 in the inter section IA is also inclined at a predetermined angle.

Therefore, when light is incident on the inter section IA, the light is reflected from the surface of the reflector 170 and is incident on the neighboring second solar cell c2.

13 shows a state in which the reflector 170 is positioned further inward than the end of the first solar cell and is coupled to the wiring material.

In FIG. 13, the reflector 170 is further formed inward by a predetermined distance t from the end of the first solar cell c1 and is attached to the wiring material 125.

On the other hand, the wiring member 125 has one side connected to the front electrode 113 of the first solar cell c1, and the other side connected to the rear electrode 115 of the second solar cell c2. Therefore, the wiring member 125 is bent from top to bottom at the end of the first solar cell c1. When the wiring member 125 made of a metal film is bent in this way, disconnection is likely to occur at the bent point.

By the way, in this embodiment, since the reflector 170 is affixed to the bent part of the wiring member 125, a problem in which the wiring member 125 is disconnected can be prevented.

14 shows a state in which the reflector 170 is formed on the front and rear surfaces of the wiring member 125 in the inter section IA.

In FIG. 14, the reflector 170 is the same as described above except that the reflector 170 is formed above and below the wiring member 125, respectively. As the reflector 170 is formed in the lower part of the wiring material as described above, it is possible to prevent the wiring material 125 from being broken in the inter section IA, and further, the reflector 170 made of a metal material is further formed in the inter section IA. As a result, the line resistance of the wiring material 125 can be reduced.

15 shows a state in which irregularities are formed on the surface of the reflector. Since the surface of the reflector 170 includes the unevenness 171 in this way, when light is reflected from the surface of the reflector 170, diffuse reflection occurs, thereby effectively increasing the amount of light incident on the solar cell.

16 shows a state in which the surface of the reflector is made of an inclined surface Cs, and an uneven surface 171 is formed on the inclined surface. 15 illustrates a rounded shape of the inclined surface Cs, but any shape may be used as long as the height changes according to the position. As such, if the reflector surface has an inclined surface Cs, the light is further refracted from the reflector surface toward the solar cell as much as it corresponds to the inclination angle, so that the amount of light incident on the solar cell can be effectively increased.

Until now, the description of the reflector has been described as an example in which one reflector 170 is disposed in the inter section IA, but at least two or more reflectors 170 may be disposed as shown in FIG. 17. In this case, all of the plurality of reflectors 170 may be arranged in the manner described with reference to FIGS. 12 to 16, or each reflector may be configured in a different shape. For example, when two reflectors 170 are present in the inter section IA, one is configured as shown in FIG. 14 and the other is configured as shown in FIG. 16.

In addition, in FIG. 17, it is described as an example that the reflector 170 is divided into a plurality in the extending direction of the wiring member, but may be divided into a plurality of parts in a direction crossing the wiring member.

Claims (26)

A solar cell having a front electrode formed on the front surface of the semiconductor substrate and including a plurality of parallel front collecting electrodes, and a rear electrode formed on the rear surface of the semiconductor substrate and including a plurality of parallel rear collecting electrodes,
A wiring member connecting the front electrode to the rear electrode of an adjacent solar cell,
A plurality of front pad portions positioned in a region where the front collecting electrode and the wiring member overlap, and having a vertical width greater than that of the front collecting electrode,
And a plurality of rear pad portions formed in a region where the rear collecting electrode and the wiring member overlap,
The pitch of the plurality of front pad portions is greater than the pitch of the plurality of front collecting electrodes, and the number of the rear pad portions is less than the number of the front pad portions.
According to claim 1
A solar cell module in which a ratio (m/n) of the number of rear pads (m) to the number of front pads (n) is 0.5≦1 <1.
The method of claim 1,
The pitch of the rear pad portion is larger than the pitch of the front pad portion.
The method of claim 3,
It is located between the rear pad portion and the rear pad portion immediately adjacent thereto, and the number of intersection points where the rear collection electrode and the wiring member cross is between the front pad portion and the front pad portion immediately adjacent thereto, and the front collection electrode A solar cell module that is greater than the number of intersections at which the and the wiring members cross.
The method of claim 1,
The rear pad portion and the front pad portion are arranged at equal intervals in the extending direction of the wiring member.
The method of claim 1,
The size of the front pad part is the same as the size of the rear pad part.
The method of claim 1,
The pitch of the front collecting electrode is equal to or greater than the pitch of the rear collecting electrode.
The method of claim 7,
A solar cell module having a line width of the rear collecting electrode equal to or greater than the line width of the front collecting electrode.
The method of claim 8,
The number of the rear collection electrodes is greater than the number of the front collection electrodes.
The method according to any one of claims 1 to 9,
The wiring material has a line width of 200 (um)-500 (um), and 10 to 15 or less wiring materials connect two adjacent solar cells.
delete delete delete delete delete delete The method of claim 1,
The front electrode further comprises a front connection electrode connecting the plurality of front pads in a direction crossing the plurality of front collection electrodes.
The method of claim 17,
The width of the front pad part is larger than the width of the front connection electrode.
The method of claim 17,
The wiring material is a solar cell module comprising a core layer made of metal and a coating layer including solder, positioned on a surface of the core layer.
The method of claim 19,
The wiring material is connected by soldering to the plurality of front pads.
The method of claim 20,
The wiring material is disposed on the front connection electrode and is connected by soldering to a plurality of front pads. The method of claim 21,
The wiring material is a solar cell module connected by soldering to the plurality of front pad portions and the front connection electrodes, respectively.
The method of claim 17,
The width of the front connection electrode is smaller than the width of the wiring member solar cell module.
The method of claim 1,
The plurality of front pad portions and the plurality of rear pad portions are positioned at different positions in the direction of the wiring member with the substrate interposed therebetween.
The method of claim 1,
The plurality of front pad portions and the plurality of rear pad portions are positioned at the same position in the direction of the wiring member with the substrate interposed therebetween.
The method of claim 1,
A solar cell module having a circular cross section of the wiring member.

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