KR102065170B1 - Solar cell module - Google Patents

Abstract

The present invention relates to a solar cell module.
A solar cell module according to an example of the present invention includes a plurality of solar cells including a semiconductor substrate, an emitter portion forming a pn junction with the semiconductor substrate, a first electrode connected to the emitter portion, and a second electrode connected to a rear surface of the semiconductor substrate. ; And a plurality of interconnectors connected to the first electrode or the second electrode to electrically connect the plurality of solar cells in series with each other. The first electrode or the first electrode provided in one solar cell in each of the plurality of solar cells. The number of the plurality of interconnectors connected to the two electrodes is between 10 and 18.

Description

Solar cell module {SOLAR CELL MODULE}

The present invention relates to a solar cell module.

With the recent prediction of the depletion of existing energy sources such as petroleum and coal, there is a growing interest in alternative energy to replace them, and thus solar cells producing electric energy from solar energy are attracting attention.

A typical solar cell includes a semiconductor portion for forming a p-n junction by different conductive types such as p-type and n-type, and electrodes connected to semiconductor portions of different conductive types, respectively.

When light is incident on the 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, which are electric charges, and electrons move toward the n-type semiconductor portion, and the holes are p. Move toward the semiconductor portion of the mold. The moved electrons and holes are collected by different electrodes connected to the n-type and p-type semiconductor parts, respectively, and are obtained by connecting these electrodes with wires.

Such solar cells may be connected to each other by an interconnector.

An object of the present invention is to provide a solar cell module with improved photoelectric conversion efficiency.

A solar cell module according to an example of the present invention includes a plurality of solar cells including a semiconductor substrate, an emitter portion forming a pn junction with the semiconductor substrate, a first electrode connected to the emitter portion, and a second electrode connected to a rear surface of the semiconductor substrate. ; And a plurality of interconnectors connected to the first electrode or the second electrode to electrically connect the plurality of solar cells in series with each other. The first electrode or the first electrode provided in one solar cell in each of the plurality of solar cells. The number of the plurality of interconnectors connected to the two electrodes is between 10 and 18.

Here, the width of the plurality of interconnectors may be between 0.24mm and 0.53mm, more preferably the width of the plurality of interconnectors may be between 0.3mm and 0.38mm.

Here, the plurality of first electrodes may be spaced apart from each other and extend in the first direction.

In addition, each of the plurality of solar cells may not include a bus bar electrode that is elongated in a second direction crossing the first direction so that the plurality of first electrodes are commonly connected.

In addition, the plurality of solar cells may be arranged in a second direction crossing the first direction, and the plurality of interconnectors may connect the plurality of solar cells in series with each other in the second direction.

In this case, the plurality of interconnectors may have a wire shape, and a cross section of each of the plurality of interconnectors may include a curved surface.

More specifically, the cross section of each of the plurality of interconnectors may be at least one of circular, elliptical, semicircular, rectangular, or trapezoidal.

Here, the second electrode may include a rear electrode layer positioned on the rear surface of the semiconductor substrate, or the second electrode may include a rear finger positioned longer in the same direction as the front finger on the rear surface of the semiconductor substrate.

In addition, the second electrode may further include a rear bus bar that is elongated in a second direction crossing the front finger on the rear surface of the semiconductor substrate.

In the solar cell module according to the present invention, the number of the plurality of interconnectors connected to the first electrode or the second electrode included in one solar cell is limited to 10 to 18, thereby improving efficiency of the solar cell module. Can improve and further reduce the manufacturing cost of the module.

1 is a view for explaining an example of a solar cell module according to the present invention.
FIG. 2 is a partial perspective view illustrating an example of a solar cell applied to the solar cell module illustrated in FIG. 1.
3 is a cross-sectional view taken along line CS3-CS3 in FIG. 2.
FIG. 4 is a graph showing an output reduction amount of the solar cell module according to the resistance of the interconnector IC shown in FIG. 1.
FIG. 5 is a graph simulating the output of the module by the remaining power generation area excluding the shading area covered by the interconnector (IC) shown in FIG.
FIG. 6 illustrates the number of interconnectors ICs when the width WIC of the interconnectors IC shown in FIG. 1 is 0.25 mm to set the number NICs of the interconnectors IC according to the present invention. Simulated module output according to (NIC).
FIG. 7 illustrates the number of interconnectors ICs when the width WIC of the interconnectors IC shown in FIG. 1 is 0.3 mm to set the number NICs of the interconnectors IC according to the present invention. Simulated module output according to (NIC).
FIG. 8 illustrates the number of interconnectors ICs when the width WIC of the interconnectors IC shown in FIG. 1 is 0.2 mm to set the number NICs of the interconnectors IC according to the present invention. Simulated module output according to (NIC).
9 is a graph comparing the material ratio and the shadowing area of the interconnectors IC for setting the number NIC of the interconnectors IC according to the present invention, respectively, with the comparative example.
FIG. 10 is a graph illustrating simulation results of output values of modules according to the width WIC of the interconnector IC when the number NICs of the interconnectors IC shown in FIG. 1 is 11;
FIG. 11 is a graph illustrating simulation results of output values of modules according to the width WIC of the interconnector IC when the number NIC of the interconnectors IC shown in FIG. 1 is thirteen.
FIG. 12 is a graph illustrating simulation results of output values of modules according to the width WIC of the interconnector IC when the number NIC of the interconnectors IC shown in FIG. 1 is 15. FIG.
FIG. 13 is a graph illustrating simulation results of output values of a module according to a width WIC of the interconnector IC when the number NICs of the interconnectors IC shown in FIG. 1 is 17. FIG.
14 to 16 are views for explaining another example of the solar cell that can be applied to the solar cell module according to the present invention shown in FIG.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. When a portion of a layer, film, region, plate, etc. is said to be "on top" of another part, this includes not only when the other part is "right over" but also when there is another part in the middle. On the contrary, when a part is "just above" another part, there is no other part in the middle. In addition, when a part is formed “overall” on another part, it means that it is not formed on the edge part as well as being formed on the entire surface of another part.

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 to which the direct light may not be incident or the reflected light may be incident.

In addition, in the following description, the meaning that the length or width of the two different components are the same means that they are the same within the error range of 10%.

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

1 is a view for explaining an example of a solar cell module according to the present invention, specifically, (a) in Figure 1 is a front view of the solar cell module according to the present invention, (b) is CS1-CS1 A cross section along the line, (c) is a cross section along the CS2-CS2 line.

2 is a partial perspective view illustrating an example of a solar cell applied to the solar cell module illustrated in FIG. 1, and FIG. 3 is a cross-sectional view taken along line CS3-CS3 in FIG. 2.

As shown in (a) to (C) of FIG. 1, a solar cell module according to the present invention includes a plurality of solar cells C1 and C2 and a plurality of interconnectors connected to the respective solar cells C1 and C2. (IC).

Here, an example of a solar cell applied to the solar cell module according to the present invention, as shown in Figures 2 and 3, the semiconductor substrate 110, the emitter portion 120, the anti-reflection film 130, a plurality of first An electrode 140, a back surface field (BSF) 172, and a second electrode 150 may be provided.

Here, the rear electric field 172 may be omitted, but when the rear electric field 172 is present, the efficiency of the solar cell is further improved. Hereinafter, the rear electric field 172 will be described as an example.

The semiconductor substrate 110 may have a first conductivity type, for example, a p-type conductivity type, and the semiconductor substrate 110 may be formed of any one of single crystal silicon, polycrystalline silicon, and amorphous silicon. In one example, the semiconductor substrate 110 may be formed of a crystalline silicon wafer.

When the semiconductor substrate 110 has a p-type conductivity type, impurities of trivalent elements, such as boron (B), gallium, and indium, are doped into the semiconductor substrate 110. However, on the other hand, the semiconductor substrate 110 may be an n-type conductive type. 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.

The front surface of the semiconductor substrate 110 has a plurality of uneven surfaces. For convenience, in FIG. 2, only the edge portion of the semiconductor substrate 110 is shown as the uneven surface, and the emitter portion 120 positioned thereon also shows only the edge portion as the uneven surface. However, substantially the entire front surface of the semiconductor substrate 110 has a concave-convex surface, and thus the emitter portion 120 located on the front surface of the semiconductor substrate 110 also has a concave-convex surface.

The light incident toward the front surface of the semiconductor substrate 110 having a plurality of unevennesses is generated by the plurality of unevennesses formed on the surface of the emitter portion 120 and the semiconductor substrate 110, and thus the semiconductor substrate 110 is subjected to a plurality of reflection operations. Incident inside. As a result, the amount of light reflected from the front surface of the semiconductor substrate 110 is reduced to increase the amount of light incident into the semiconductor substrate 110. In addition, due to the uneven surface, the surface area of the semiconductor substrate 110 and the emitter portion 120 to which light is incident increases, thereby increasing the amount of light incident on the semiconductor substrate 110.

As shown in FIGS. 2 and 3, the emitter unit 120 is formed on the entire surface of the first conductive type semiconductor substrate 110 and is the second conductive type opposite to the first conductive type, for example. For example, an n-type conductivity type impurity may be a region doped in the semiconductor substrate 110, and may be disposed on a surface on which light is incident, that is, inside the front surface of the semiconductor substrate 110. Therefore, the emitter portion 120 of the second conductivity type forms a p-n junction with the first conductivity type portion of the semiconductor substrate 110.

The light incident on the semiconductor substrate 110 may be separated into electrons and holes so that the electrons may move toward the n-type and the holes may move toward the p-type. Therefore, when the semiconductor substrate 110 is p-type and the emitter portion 120 is n-type, the separated holes may move toward the rear surface of the semiconductor substrate 110 and the separated electrons may move toward the emitter portion 120.

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

When the emitter portion 120 has an n-type conductivity type, the emitter portion 120 may be formed by doping the semiconductor substrate 110 with impurities of a pentavalent element. The impurities of the trivalent element may be formed by doping the semiconductor substrate 110.

The anti-reflection film 130 is positioned above the incident surface of the semiconductor substrate 110, and as shown in FIGS. 2 and 3, when the emitter part 120 is positioned at the incident surface of the semiconductor substrate 110, The anti-reflection film 130 may be located above the emitter part 120.

The anti-reflection film 130 may include a hydrogenated silicon nitride film (SiNx: H), a hydrogenated silicon oxide film (SiOx: H), a hydrogenated silicon nitride oxide film (SiNxOy: H), and a hydrogenated amorphous silicon (a-Si: H). It may include at least one of).

Such an anti-reflection film 130 is a defect such as a dangling bond mainly existing on and near the surface of the semiconductor substrate 110 due to hydrogen (H) included in the anti-reflection film 130. To pass through the passivation function to reduce the disappearance of the charges transferred to the surface of the semiconductor substrate 110 by the defect. Therefore, the amount of electric charge lost on or near the surface of the semiconductor substrate 110 due to the defect is reduced.

When the semiconductor substrate 110 has an uneven surface, the anti-reflection film 130 may have an uneven surface having a plurality of uneven surfaces similar to the semiconductor substrate 110.

Generally, since defects are mainly present on or near the surface of the semiconductor substrate 110, the passivation function is further improved when the anti-reflection film 130 is in direct contact with the surface of the semiconductor substrate 110 as in the case of the embodiment.

In addition, the anti-reflection film 130 may include the hydrogenated silicon nitride film (SiNx: H), the hydrogenated silicon oxide film (SiOx: H), the hydrogenated silicon nitride oxide film (SiNxOy: H), and the hydrogenated silicon oxynitride film (SiOxNy). At least one of: H) and hydrogenated amorphous silicon (a-Si: H) may be formed of a plurality of layers.

For example, the anti-reflection film 130 may be formed of two layers of hydrogenated silicon nitride film (SiNx: H).

By doing in this way, the passivation function of the anti-reflection film 130 can be strengthened more, and the photoelectric efficiency of a solar cell can be improved further.

As illustrated in FIGS. 2 and 3, the plurality of first electrodes 140 are positioned on the front surface of the semiconductor substrate 110, and are spaced apart from each other on the front surface of the semiconductor substrate 110. It can be positioned long stretched x).

As described above, the electrodes spaced apart from each other on the front surface of the semiconductor substrate 110 and extended in the first direction x may be referred to as front fingers.

In this case, the plurality of first electrodes 140 may be connected to the emitter unit 120 by passing through the anti-reflection film 130.

Accordingly, the plurality of first electrodes 140 may be made of at least one conductive material such as silver (Ag) to collect charges, for example, electrons, which are moved toward the emitter unit 120.

In this case, the solar cell according to the present invention may not include a bus bar electrode formed to extend in a second direction y crossing the first direction x such that the plurality of first electrodes 140 are commonly connected.

Typically, a bus bar electrode is connected to the interconnector IC connecting the plurality of solar cells C1 and C2 to each other. In the solar cell according to the present invention, the bus bar electrode is not provided. ) May be directly connected to each of the plurality of first electrodes 140 described above.

The rear electric field unit 172 may be disposed on a rear surface opposite to the front surface of the semiconductor substrate 110, and a region in which impurities of the same conductivity type as the semiconductor substrate 110 are doped at a higher concentration than the semiconductor substrate 110, eg, For example, the P + region.

The potential barrier is formed due to the difference in the impurity concentration between the first conductive region of the semiconductor substrate 110 and the backside electric field 172, thereby preventing electrons from moving toward the backside electric field 172, which is the movement direction of the hole. On the other hand, it facilitates the movement of holes toward the rear electric field 172. Therefore, the amount of charge lost due to the recombination of electrons and holes in the rear surface and the vicinity of the semiconductor substrate 110 is reduced, and the movement of the desired charge (eg, holes) is accelerated to reduce the amount of charge transfer to the second electrode 150. Increase.

The second electrode 150 may include a rear electrode layer 151 and a plurality of rear bus bars 152. The rear electrode layer 151 is in contact with the rear electric field unit 172 positioned at the rear of the semiconductor substrate 110, and substantially except for a portion where the rear edge and the rear busbar 152 are positioned on the semiconductor substrate 110. It may be located on the entire rear surface of the semiconductor substrate 110.

The back electrode layer 151 contains a conductive material such as aluminum (Al).

The back electrode layer 151 collects charges, for example, holes, moving from the back field 172.

In this case, since the rear electrode layer 151 is in contact with the rear electric field unit 172 which maintains the impurity concentration higher than that of the semiconductor substrate 110, the semiconductor substrate 110, that is, the rear electric field unit 172 and the rear electrode layer 151 are in contact with each other. The contact resistance between the electrodes is reduced, so that the charge transfer efficiency from the semiconductor substrate 110 to the back electrode layer 151 is improved.

The plurality of rear busbars 152 are positioned on the rear surface of the semiconductor substrate 110 where the rear electrode layer 151 is not located and are connected to the adjacent rear electrode layer 151.

The plurality of rear bus bars 152 may collect charges transferred from the rear electrode layer 151.

An interconnector IC is connected to the plurality of rear busbars 152 so that charges (eg, holes) collected by the plurality of rear busbars 152 are transferred to another adjacent solar cell through the interconnector IC. Can be.

The plurality of rear busbars 152 may be made of a material having a better conductivity than the rear electrode layer 151, and may contain at least one conductive material such as silver (Ag).

Each of the plurality of rear busbars 152 may be connected to a respective interconnector (IC).

Operation of the solar cell according to the present embodiment having such a structure is as follows.

When light is irradiated to the solar cell and incident on the emitter unit 120, which is a semiconductor unit, and the semiconductor substrate 110 through the emitter unit 120, electron-hole pairs are generated in the semiconductor unit by light energy. At this time, the reflection loss of the light incident on the semiconductor substrate 110 by the uneven surface of the semiconductor substrate 110 and the emitter portion 120 is reduced, thereby increasing the amount of light incident on the semiconductor substrate 110.

These electron-hole pairs are separated from each other by the pn junction of the semiconductor substrate 110 and the emitter portion 120 so that the electrons and holes are, for example, of the emitter portion 120 and the p-type having an n-type conductivity type. Each move toward the semiconductor substrate 110 having the conductivity type. As such, the electrons moved toward the emitter unit 120 are collected by the plurality of first electrodes 140 and transferred to the interconnector IC, and the holes moved toward the semiconductor substrate 110 are adjacent to the adjacent rear electrode layer 151. Collected by a plurality of rear busbars 152 and delivered to the interconnect (IC).

2 and 3, the first electrode 140 is positioned on the front surface of the semiconductor substrate 110 and the second electrode 150 is positioned on the rear surface of the semiconductor substrate 110. Although the structure of the conventional solar cell is described as an example, the solar cell module according to the present invention has a solar cell having a structure in which the first electrode 140 and the second electrode 150 are located on the rear surface of the semiconductor substrate 110. It is also possible to apply.

2 and 3 illustrate a case in which the rear bus bar 152 is included in the rear surface of the semiconductor substrate 110, the rear bus bar 152 may be omitted. That is, the second electrode 150 may be formed only by the rear electrode layer 151.

In addition, one example of a solar cell applied to the solar cell module of the present invention can be various forms in addition to this, after the first description on the number and width of the interconnector (IC) applied to the solar cell module according to the present invention, It demonstrates in FIGS. 14-16.

Hereinafter, for convenience of description, a case having the structure of the solar cell shown in FIGS. 2 and 3 will be described as an example.

Next, as shown in (a) of FIG. 1 again, in the solar cell module according to the present invention, the length direction of the first electrode 140 of each of the plurality of solar cells C1 and C2 is the first direction x. The plurality of solar cells C1 and C2 may be arranged in a second direction y crossing the first direction x.

At this time, as shown in (a) to (c) of FIG. 1, the plurality of interconnectors (IC) or the first electrode 140 or in order to electrically connect the plurality of solar cells (C1, C2) in series with each other It may be connected to the second electrode 150.

More specifically, as shown in FIG. 1B, in the solar cell module according to the present invention, the plurality of interconnectors ICs are elongated in the second direction y to extend the first solar cell. The electrode 140 and the second electrode 150 of the second solar cell may be connected in series.

In this case, the plurality of interconnectors IC according to the present invention may have a wire shape. In this case, as shown in FIG. 1A, a cross section of each of the plurality of interconnectors IC may include a curved surface. That is, in FIG. 1A, the cross section of each of the plurality of interconnectors IC is shown as an example. However, the cross section of each of the plurality of interconnectors IC is an ellipse, a semi-circle, a rectangle, or a trapezoid. It may include one.

Accordingly, light incident from the outside is reflected by the inclined surface of the interconnector IC to be incident toward the semiconductor substrate 110 or to be reflected back to the transparent substrate positioned on the front surface of the plurality of solar cells C1 and C2 or the semiconductor substrate. The light incident on the solar cell may be maximized by allowing the light to be incident toward the 110.

The plurality of interconnectors IC include solder paste or conductive metal particles containing a metal material such as tin (Sn) in the first electrode 140 or the second electrode 150 of the solar cell in the insulating resin. Conductive materials such as conductive paste or conductive adhesive film may be used.

Meanwhile, in the solar cell module of the present invention, the number NIC and the width WIC of the plurality of interconnectors IC may be limited to specific values.

That is, in consideration of the resistance of the plurality of interconnectors (IC), the shading area covered by the plurality of interconnectors (IC), and the output of the solar cells, the plurality of solar cells of the solar cell module of the present invention ( In each of C1 and C2, the number NIC of the plurality of interconnectors IC connected to the first electrode 140 or the second electrode 150 included in one solar cell may be between 10 and 18. The width WIC of the interconnect IC may be between 0.24 mm and 0.53 mm.

Here, the reason for limiting the number (NIC) of the interconnectors (IC) in the solar cell module according to the present invention will be described.

For reference, the output values of the modules shown in the graphs of FIGS. 4 to 5 are exemplary and not absolute values, and may be changed depending on the configuration of each solar cell, the number of solar cells applied to the module, or other conditions. do.

FIG. 4 is a graph showing the output reduction amount of the solar cell module according to the resistance of the interconnector IC shown in FIG. 1.

In FIG. 4, without considering the shading area of the semiconductor substrate 110 covered by the interconnector IC, the resistance of the interconnector IC and the output reduction amount of the output of the solar cell module are reduced. The results of simulating the relationship are shown.

Referring to FIG. 4, it can be seen that the output reduction amount of the solar cell module decreases as the width WIC and the number NIC of the interconnectors IC increase.

In more detail, as the number NIC and the width WIC of the interconnectors IC decrease, the resistance of the interconnectors IC increases, thereby increasing the output reduction amount of the solar cell module. That is, as the number NIC and the width WIC of the interconnectors increase, the resistance by the interconnector IC improves, thereby reducing the output reduction amount.

In addition, even if the number NIC and the width WIC of the interconnectors increase to some extent, the output reduction of the solar cell module converges to about 0.05W.

As a result, as the number NIC and the width WIC increase, the resistance decreases, so that the output of the solar cell module increases. In addition, the number IC and the number of interconnectors IC After increasing the width (WIC) to some extent, it can be seen that the output increase of the module is slowed down.

This is because the resistance of the interconnector IC decreases as the number NIC and the width WIC of the interconnector IC increases, and when the resistance of the interconnector IC improves to a certain level or less, It can be interpreted that the output reaches the maximum value of the output possible by each solar cell.

At this time, when the width WIC of the interconnector IC is relatively small (for example, when the width WIC is 0.15 mm), the difference in output reduction amount by the number of interconnectors ICs NIC is relatively different. When the width WIC of the interconnector IC is relatively large (for example, when the width WIC is 0.4 mm), the difference in output reduction by the number of interconnectors NICs is shown. It can be seen that appears relatively small.

FIG. 5 is a graph simulating the module output by the remaining power generation area except for the shading area covered by the interconnector IC shown in FIG.

The graph shown in FIG. 5 is a value excluding the influence of the resistance of the interconnector IC.

In FIG. 5, when there is no interconnector (IC), the number (NIC) and width (WIC) of the interconnectors (ICs) applied to the module are set as an example where the maximum output of each cell in the solar cell module is 5W. ), The output value of the output solar cell was simulated.

As shown in FIG. 5, it can be seen that as the number NIC and the width WIC of the interconnectors IC increase, the shading area by the interconnectors IC increases to decrease the output of the solar cell.

At this time, when the width WIC of the interconnector IC is small, the output variation of the solar cell appears to be relatively small even if the number NIC of the interconnectors IC is large or small. When the width WIC is increased, the number of interconnectors ICs is relatively affected, and thus the output of the solar cell is greatly changed.

That is, as the number NIC of the interconnectors IC increases, the influence of the width WIC of the interconnectors IC increases relatively, so that the output of the solar cell decreases relatively.

Therefore, when the width WIC of the interconnector IC is 0.15 mm, the shading area covered by the interconnector IC is increased even if the number of interconnectors ICs varies from 7 to 21. Because it is not large, the output of the solar cell does not significantly decrease.

However, when the width WIC of the interconnector IC is 0.4 mm, the shading area covered by the interconnector IC when the number of interconnectors IC increases from 7 to 21. This greatly increases the output of the solar cell can be seen to significantly decrease.

As such, it can be seen from the simulation results as shown in FIGS. 4 and 5 that when the number NIC and the width WIC of the interconnectors IC are increased, the resistance by the interconnectors IC decreases but the interconnections are reduced. If the shading area obscured by the connector (IC) increases, it affects the output of the solar cell, and if the number of ICs (NIC) and width (WIC) decreases, the resistance increases but the shading area is relative. It can be seen that the reduction affects the output of the solar cell.

Therefore, it can be seen that by properly determining the number (NIC) and the width (WIC) of the interconnect (IC) it can be more maximized the output of each solar cell applied to the module.

Therefore, in the present invention, first, in order to find the appropriate number of interconnectors ICs, first, the width WIC of the interconnectors IC is arbitrarily set, so that the number of interconnectors ICs in each width WIC. We simulated the module output according to (NIC).

FIG. 6 illustrates the number of interconnectors ICs when the width WIC of the interconnectors IC shown in FIG. 1 is 0.25 mm to set the number NICs of the interconnectors IC according to the present invention. The result of simulating the module output according to (NIC), Figure 7 is a width (WIC) of the interconnect (IC) shown in Figure 1 to set the number (NIC) of interconnectors (IC) according to the invention Is 0.3mm, it is the result of simulating the module output according to the number NIC of interconnectors (IC), Figure 8 is to set the number of interconnectors (IC) according to the present invention, Figure 1 When the width WIC of the interconnector IC illustrated in FIG. 2 is 0.2 mm, the output of the module is simulated according to the number NIC of the interconnectors IC.

For reference, the output values of the modules shown in the graphs of FIGS. 6 to 8 are exemplary, and are not absolute values, and may be changed depending on the configuration of each solar cell or the number of solar cells applied to the module or other conditions. do.

6 to 8, for example, the maximum allowable output power of each solar cell is 5W, and 60 solar cells are applied to one solar cell module as an example. Therefore, the maximum output power of one solar cell module is 300W.

6 to 8, the comparative example of the solar cell module shown in FIG. 1 shows that when the number of interconnectors ICs is 3 and the width WIC is 1.5 mm, This is the result of simulating the output. At this time, the output of the solar cell module is 285.4W.

6 to 8, the module output according to the number NIC of the interconnectors IC is a simulation result considering both the resistance and the shading area of the interconnectors IC.

First, as shown in FIG. 6, when the width WIC of the interconnector IC is 0.25 mm, the number NIC of the interconnectors IC has a lower output value than that of the comparative example. , 10 to 28 has a higher output than the comparative example, and from more than 29 it can be seen that having a lower output value than the comparative example. At this time, the maximum output power of the module was when the number of interconnectors ICs was 17, and the output value was 287.5W, which was approximately 2W higher than the output value of the comparative example.

In addition, as shown in FIG. 7, when the width WIC of the interconnector IC is 0.3 mm, an output value lower than that of the comparative example may be obtained when the number of interconnectors ICs is less than one to seven. From 7 to 26, it has a higher output than the comparative example, and from more than 27 it can be confirmed to have a lower output value than the comparative example. At this time, the maximum output power of the module was when the number of interconnectors ICs was 13, and the output value was 288.6W, which was approximately 3.2W higher than the output value of the comparative example.

In addition, as shown in FIG. 8, when the width WIC of the interconnector IC is 0.2 mm, an output value lower than the number of interconnectors ICs from 1 to 19 is lower than that of the comparative example. From 19 to 32, the output has a higher output than the comparative example, and from more than 32, it can be confirmed that the output value is lower than the comparative example. At this time, the maximum output power of the module was when the number of interconnectors ICs was 24, and the output value was 286.03W, which was approximately 0.63W higher than the output value of the comparative example.

Here, as a result of the simulation, when the width WIC of the interconnector IC is 0.2 mm, the maximum output value is less than 1 W compared to the comparative example, and thus the number of interconnectors ICs of the present invention is not a difference in the meaningful output value. Except for the reason for setting (NIC), it set based on FIG. 6 and FIG.

6 and 7, it can be seen that the number NIC of interconnectors ICs, which always have a higher output value than the comparative example, is between 10 and 26.

In addition, in the range of the number (NIC) of the interconnect (IC) having a higher output value than the comparative example, the present invention compared the material cost and shadow area of the interconnect (IC) compared with the case of the comparative example.

9 is a graph comparing the material ratio and the shadowing area of the interconnectors IC for setting the number NIC of the interconnectors IC according to the present invention, respectively, with the comparative example.

Here, the comparative example is a case where the number (NIC) of the interconnector (IC) is three, the width (WIC) is 1.5mm, the interconnector (IC) according to the present invention is a case where the width (WIC) is 0.25mm It set as an example.

As shown in (a) of FIG. 9, it can be seen that the material cost of the interconnector IC consumes the same material cost as that of the comparative example when the number NIC of the interconnectors IC per cell is 32.

Therefore, when the number of interconnectors (IC) is 32 or less, it can be seen that the material cost of the interconnector (IC) according to the present invention is further reduced than the comparative example.

In addition, as shown in (b) of FIG. 9, when the width WIC is 0.25 mm, when the number NIC of interconnectors IC is 18, it can be seen that it has the same shadow area as the comparative example. In the case where the number of interconnectors ICs exceeds 18, the shadow area is increased compared to the comparative example.

Accordingly, considering the simulation results of FIGS. 6 to 8 and the graph of FIG. 9, when the number of interconnectors ICs does not exceed 18, the material cost of the interconnectors IC is further reduced. It turns out that a shadow area is below a comparative example.

Therefore, when considering the Fig. 9 in the 10 ~ 26 derived from Fig. 6 and 7, it can be seen that the number (NIC) of the interconnect (IC) is more efficient and cheaper.

6 to 9, the number NIC of interconnectors ICs in the solar cell module according to the present invention is determined to be between 10 and 18.

In addition, the width WIC of the interconnector IC according to the present invention is simulated for several cases in a state where the number NIC of the interconnectors IC as described above is determined, and has an optimal module output. The width WIC of the connector IC was set.

10 to 13, the simulation result graph shows the module output according to the width (WIC) of the interconnector (IC) when the number of interconnectors (IC) is 11, 13, 15, or 17. Simulation results for the graph.

Specifically, FIG. 10 is a graph showing simulation results of output values of modules according to the width WIC of the interconnector IC when the number NICs of the interconnectors IC shown in FIG. 1 is 11, and FIG. FIG. 1 is a simulation result graph of output values of a module according to the width WIC of the interconnector IC when the number NIC of the interconnectors IC shown in FIG. 1 is 13, and FIG. 12 is shown in FIG. When the number NIC of the interconnectors IC is 15, a simulation result graph of the output value of the module according to the width WIC of the interconnector IC is shown, and FIG. 13 is the interconnector IC shown in FIG. When the number of NICs is 17, it is a graph of the simulation result of the output value of the module according to the width (WIC) of the interconnect (IC).

The output values of the modules shown in the graphs of FIGS. 10 to 13 are exemplary and are not absolute values, and may be changed by other conditions such as the configuration of each solar cell or the number of solar cells applied to the module.

10 to 13, for example, the maximum allowable output of each solar cell is 5W, and 60 solar cells are applied to one solar cell module as an example. Therefore, the maximum output power of one solar cell module is 300W.

Here, in the comparative example, the number NIC of the interconnectors IC is three and the width WIC is 1.5 mm, and the output value of the solar cell module according to the comparative example is 285.4W.

First, as shown in FIG. 10, when the number NICs of the interconnectors IC is 11, the solar cell module according to the present invention when the width WIC of the interconnectors IC is 0.24 mm to 0.85 mm. It can be seen that the output of the solar cell module according to the comparative example is better, and furthermore, when the width (WIC) of the interconnector (IC) is 0.3mm to 0.67mm the output of the solar cell module according to the present invention is 288W It can be confirmed that the above is good.

At this time, the maximum output of the solar cell module is when the width (WIC) of the interconnector (IC) is 0.4mm, the output value is 289.4W, 4W higher than the output value of the comparative example.

Next, as shown in FIG. 11, when the number NIC of the interconnectors IC is 13, the solar cell module according to the present invention when the width WIC of the interconnectors IC is 0.24 mm to 0.72 mm. It can be seen that the output of the solar cell module according to the comparative example is better, and furthermore, when the width (WIC) of the interconnector (IC) is 0.28mm to 0.54mm, the output of the solar cell module according to the present invention is 288W It can be confirmed that the above is good.

At this time, the maximum output power of the solar cell module was when the width (WIC) of the interconnector IC was 0.38 mm, and the output value was 289.3W, which was about 3.9W higher than the output value of the comparative example.

Next, as shown in FIG. 12, when the number NIC of the interconnectors IC is 15, the solar cell module according to the present invention when the width WIC of the interconnectors IC is 0.22 mm to 0.62 mm. It can be seen that the output of the solar cell module according to the comparative example is better, and furthermore, when the width (WIC) of the interconnector (IC) is 0.28mm to 0.45mm the output of the solar cell module according to the present invention is 288W It can be confirmed that the above is good.

At this time, the maximum output of the solar cell module is when the width (WIC) of the interconnector (IC) is 0.35mm, the output value is 288.7W, 3.3W higher than the output value of the comparative example.

Next, as shown in FIG. 13, when the number NIC of interconnectors IC is 17, the solar cell module according to the present invention when the width WIC of the interconnectors IC is 0.21 mm to 0.53 mm. It can be seen that the output of the solar cell module according to the comparative example is better, and furthermore, when the width (WIC) of the interconnector (IC) is 0.28mm to 0.38mm, the output of the solar cell module according to the present invention is 288W It can be confirmed that the above is good.

At this time, the maximum output of the solar cell module was when the width (WIC) of the interconnector (IC) is 0.3mm, the output value is 288.7W, 3.3W higher than the output value of the comparative example.

Accordingly, considering the simulation result graphs according to FIGS. 10 to 13, when the number NICs of the interconnectors IC is between 10 and 18, as in the present invention, the width of the interconnectors IC is WIC. ) Is between 0.24 mm and 0.53 mm, it can be seen that the output value of the solar cell module is better than the comparative example.

In addition, when the number NIC of the interconnectors (IC) is between 10 and 18, the width (WIC) of the interconnector (IC) according to the present invention according to the present invention may be between 0.3mm and 0.38mm. . At this time, as shown in Figures 10 to 13 above, it can be seen that the output value of the solar cell module is much better than the comparative example.

14 to 16, another example of the solar cell that can be applied to the solar cell module according to the present invention illustrated in FIG. 1 will be described.

In the following FIGS. 14 to 16, detailed descriptions of overlapping contents with those described in FIGS. 2 and 3 will be omitted, and the description will be mainly focused on different points.

Another example of a solar cell that may be applied to the solar cell module according to the present invention illustrated in FIG. 1 is different from that of FIGS. 2 and 3, as shown in FIG. 14. In addition to the front finger 141 extending in a long direction, it may be provided with a front bus bar 142 extended in the second direction (y) which is a direction crossing the longitudinal direction of the front finger 141.

In this case, the interconnector IC described above in FIGS. 1 and 4 to 13 may be connected to the front busbar 142.

In this case, the number of front bus bars 142 may be equal to the number of interconnectors IC, and the width of the front bus bars 142 may be equal to or smaller than the width of the interconnect ICs. That is, in one example, when 15 interconnectors IC are connected to the front surface of the semiconductor substrate 110 with a width of 0.3 mm, 15 front busbars 142 also have a width of 0.3 mm. It can be formed on the front.

As such, when the front bus bar 142 is formed, the connection area between the interconnect IC and the first electrode 140 may be increased, thereby further improving contact resistance and contact force.

In addition, the number of rear busbars 152 may be equal to the number of interconnectors IC, and the width of the rear busbars 152 may be equal to or smaller than the width of the interconnectors IC. However, as described above with reference to FIGS. 2 and 3, the rear busbar 152 may be omitted.

In addition, as shown in FIG. 15, the rear bus bar 152 is elongated in the second direction y, connected to each front finger 141, and spaced apart from each other between the front fingers 141. It is also possible to have the form of an island structure.

In addition, unlike the above-described pattern of the second electrode 150, instead of the rear electrode layer 151, the rear finger 151 ′ which is elongated in the same direction as the front finger 141 is provided on the rear surface of the semiconductor substrate 110. In the provided state, the above-described rear bus bar 152 may be provided.

In such a case, when the solar cell has a bi-facial structure, light may be received even on the rear surface of the semiconductor substrate 110, so that the efficiency of the solar cell may be further improved.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (12)

A semiconductor substrate, an emitter portion formed on a front surface of the semiconductor substrate and forming a pn junction with the semiconductor substrate, a rear electric field portion formed on a rear surface of the semiconductor substrate, and a emitter portion located on a front surface of the semiconductor substrate A plurality of solar cells including a first electrode connected to the second electrode and a second electrode positioned on a back surface of the semiconductor substrate and connected to the rear electric field; And
And a plurality of interconnectors electrically connecting the plurality of solar cells in series with each other.
The first electrode includes a plurality of finger electrodes spaced apart from each other and extending in a first direction, and a plurality of front bus bars extending in a second direction crossing the plurality of finger electrodes and connecting the plurality of finger electrodes.
The second electrode may include a rear electrode layer connected to the rear electric field and a plurality of rear surfaces positioned in a rear surface of the semiconductor substrate at the same position as the plurality of front bus bars with the semiconductor substrate therebetween and extending in the second direction. Including busbars,
The plurality of interconnectors respectively connect the plurality of front busbars of the first solar cell and the plurality of rear busbars of the second solar cell positioned adjacent to each other of the plurality of solar cells,
The number of the plurality of front busbars, the number of the plurality of rear busbars, and the number of the plurality of interconnectors each connected 1: 1 to the plurality of front busbars or the plurality of rear busbars are the same. And 6 or more and 33 or less, and each of the plurality of interconnectors has a width and a thickness of 0.24 mm to 0.53 mm, respectively. delete According to claim 1,
And a width of the plurality of interconnectors is between 0.3 mm and 0.38 mm. delete delete According to claim 1,
The plurality of solar cells are arranged in a second direction crossing the first direction,
And the plurality of interconnectors connect the plurality of solar cells in series with each other in the second direction. The method of claim 6,
The plurality of interconnector is a solar cell module having a wire form. The method of claim 6,
A cross section of each of the plurality of interconnectors comprises a curved surface. The method of claim 6,
A cross section of each of the plurality of interconnectors is any one of a circular, elliptical, semi-circular, rectangular, or trapezoidal. According to claim 1,
The rear electrode layer is formed of aluminum (Al), and the plurality of rear bus bars are formed of silver (Ag). According to claim 1,
The rear electrode layer is disposed on the entire rear surface of the semiconductor substrate except for the rear edge of the semiconductor substrate and the plurality of rear busbars. delete

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