KR101284278B1

KR101284278B1 - Solar cell module and interconnector used in solar cell module

Info

Publication number: KR101284278B1
Application number: KR1020110033682A
Authority: KR
Inventors: 신명준; 조근태; 이성은; 조성연
Original assignee: 엘지전자 주식회사
Priority date: 2011-04-12
Filing date: 2011-04-12
Publication date: 2013-07-08
Also published as: KR20120116120A

Abstract

The present invention relates to a solar cell module and the interconnector used in the solar cell module.
One example of a solar cell module according to the present invention includes a semiconductor substrate containing a first type of impurity, an emitter part containing a second type of impurity to form a pn junction with a semiconductor substrate, and an emitter part formed on an upper surface of a rear surface of the semiconductor substrate. A first solar cell including a plurality of first electrodes electrically connected to each other, and a plurality of second electrodes formed on the rear surface of the semiconductor substrate and alternately spaced apart from the plurality of first electrodes and electrically connected to the semiconductor substrate; A second solar cell; And electrically connecting the plurality of first electrodes of the first solar cell and the plurality of second electrodes of the second solar cell to each other in series or to the plurality of first electrodes of the first solar cell and the plurality of first electrodes of the second solar cell. Are electrically connected in series with each other, and a plurality of insulating layers are formed on a portion of the surface in contact with the first solar cell and the second solar cell.

Description

SOLAR CELL MODULE AND INTERCONNECTOR USED IN SOLAR CELL MODULE}

The present invention relates to a solar cell module and the interconnector used in the solar cell module.

With the recent prediction of the depletion of existing energy resources such as oil and coal, there is a growing interest in alternative energy to replace them, and accordingly, solar cells that produce electric energy from solar energy are attracting attention.

BACKGROUND ART A typical solar cell includes a substrate and an emitter made of semiconductors of different conductive types, such as p-type and n-type, and electrodes 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.

When light is incident on the solar cell, a plurality of electron-hole pairs are generated in the semiconductor, and the generated electron-hole pairs are separated into electrons and holes charged by the photovoltaic effect, respectively, and the electrons and holes are n-type. Move toward the semiconductor and the p-type semiconductor, for example toward the emitter portion and the substrate, respectively, and are collected by electrodes electrically connected to the substrate and the emitter portion, which are connected by wires to obtain power.

An object of the present invention is to provide a solar cell module and an interconnector used in the solar cell module that can improve the photoelectric conversion efficiency.

One example of a solar cell module according to the present invention includes a semiconductor substrate containing a first type of impurity, an emitter part containing a second type of impurity to form a pn junction with a semiconductor substrate, and an emitter part formed on an upper surface of a rear surface of the semiconductor substrate. A first solar cell including a plurality of first electrodes electrically connected to each other, and a plurality of second electrodes formed on the rear surface of the semiconductor substrate and alternately spaced apart from the plurality of first electrodes and electrically connected to the semiconductor substrate; A second solar cell; And electrically connecting the plurality of first electrodes of the first solar cell and the plurality of second electrodes of the second solar cell to each other in series or to the plurality of first electrodes of the first solar cell and the plurality of first electrodes of the second solar cell. The electrical connection in series with each other, the portion of the surface in contact with the first solar cell and the second solar cell includes an interconnector comprising a plurality of insulating layers.

Here, the interconnector may include a conductive layer of an electrically conductive material electrically connecting the first solar cell and the second solar cell to each other in series; And a plurality of insulating layers partially formed on the side of the conductive layer in contact with the first solar cell and the second solar cell to prevent the first electrode and the second electrode immediately adjacent to each other from being shorted to each other. .

In addition, the conductive layer may include a plurality of first conductive layers in contact with the plurality of first electrodes or the plurality of second electrodes, and a second conductive layer electrically connecting the plurality of first conductive layers to each other.

In addition, the length of the plurality of insulating layers may be wider than the width of the first electrode or the second electrode in contact with each of the plurality of insulating layers.

The length of at least one of the plurality of first conductive layers in contact with the first solar cell is longer than the length of at least one of the plurality of insulating layers in contact with the first solar cell, and the plurality of first conductive layers in contact with the second solar cell. The length of at least one of the layers may be shorter than the length of at least one of the plurality of insulating layers in contact with the second solar cell.

In addition, the thickness of the plurality of first conductive layers in the interconnector may be the same as the thickness of the plurality of insulating layers.

Further, in the first solar cell and the second solar cell, each of the plurality of first electrodes includes at least one first portion having a first width and at least one second portion having a second width less than the first width, the first aspect In the cell and the second solar cell each of the plurality of second electrodes includes at least one third portion having a third width and at least one fourth portion having a fourth width greater than the third width, wherein the interconnector is connected to the first solar cell. The first portion and the fourth portion of the second solar cell can be electrically connected to each other.

In addition, the length of each of the plurality of first conductive layers in contact with the first portion of the first solar cell and the fourth portion of the second solar cell is equal to the length of the second portion of the first solar cell and the second solar cell. It may be longer than the length of each of the plurality of insulating layers in contact with the three portions.

In addition, the interconnector electrically connecting the plurality of solar cells to each other may include a conductive layer of an electrically conductive material electrically connecting the plurality of solar cells to each other in series; And a plurality of insulating layers partially formed on one surface of the side of the conductive layer to prevent a short circuit.

The interconnector may be formed on an opposite surface of the conductive layer on which the plurality of insulating layers are not formed, and may further include a base layer made of an insulating material.

In addition, the length of at least one of the plurality of first conductive layers may be longer than the length of at least one of the plurality of insulating layers.

In another example, the length of the first conductive layer in a portion of the interconnect may be longer than the length of the insulating layer, and in at least a portion of the remaining portions of the interconnect the length of the first conductive layer may be shorter than the length of the insulating layer.

As described above, the solar cell module according to the present invention has an effect of improving the efficiency of the solar cell module and shortening the process time by using an interconnector that prevents adjacent electrodes from being shorted to each other.

1 is an example of some perspective view of an interdigitated back contact (IBC) in accordance with the present invention.
FIG. 2 is a cross-sectional view of the solar cell shown in FIG. 1 cut along the line II-II.
3 is an example of a partial perspective view of a back junction hybrid solar cell in accordance with the present invention.
4 is a cross-sectional view of the solar cell shown in FIG. 3 taken along the line IV-IV.
5 is an example of a partial perspective view of a metal wrap through (MWT) solar cell according to the present invention.
6 is a cross-sectional view of the solar cell illustrated in FIG. 5 taken along the line VI-VI.
7 is an example of a partial perspective view of an emitter wrap through (EWT) solar cell in accordance with the present invention.
FIG. 8 is a cross-sectional view of the solar cell illustrated in FIG. 7 taken along the line VII-VII.
9 is a view for explaining an example of the pattern of the first electrode and the second electrode in the solar cell according to the present invention in more detail.
FIG. 10 is a view schematically illustrating a first electrode and a second electrode of another pattern for comparison with the first electrode and the second electrode according to the present invention.
11 to 14 are views for explaining an example of the solar cell module and the interconnector when the solar cell according to the present invention has a pattern of the first electrode and the second electrode according to FIG.
15 is a view for explaining another example of the pattern of the first electrode and the second electrode in the solar cell according to the present invention in more detail.
16 is a view for explaining an example of the solar cell module according to the present invention, when the solar cell according to the present invention has a pattern of the first electrode and the second electrode according to 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. 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, a solar cell and a solar cell module according to an embodiment of the present invention will be described with reference to the accompanying drawings.

First, the solar cell of various structures according to the present invention will be described in detail with reference to FIGS. 1 to 6.

1 is an example of a partial perspective view of an interdigitated back contact (IBC) according to the present invention, and FIG. 2 is a cross-sectional view of the solar cell shown in FIG. 1 taken along line II-II.

1 and 2, a first example 1 of a solar cell according to the present invention includes a semiconductor substrate 110, an antireflection film 130, an emitter part 120, a back surface field; BSF 140, a plurality of first electrodes 121, and a plurality of second electrodes 141 may be provided.

Here, the anti-reflection film 130 and the rear electric field unit 140 may be omitted, and are also located between the anti-reflection film 130 and the semiconductor substrate 110 to which light is incident, and have the same conductivity as that of the semiconductor substrate 110. It is also possible to further include a front electric field portion which is an impurity portion containing a type of impurity at a higher concentration than the semiconductor substrate 110.

Hereinafter, as illustrated in FIGS. 1 and 2, an anti-reflection film 130 and a rear electric field unit 140 will be described as an example.

The semiconductor substrate 110 is a semiconductor substrate made of silicon of a first conductivity type, for example, an n-type conductivity. At this time, since the substrate 100 has an n-type conductivity type, the semiconductor substrate 110 is formed of 5, such as nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi). It may contain an impurity of a valent element.

Alternatively, the semiconductor substrate 110 may be a p-type conductive type. In this case, the semiconductor substrate 110 may include boron (B), aluminum (Na), gallium (Ga), indium (In), and titanium ( It may contain impurities of trivalent elements such as Ti).

The upper surface of this semiconductor substrate 110 is textured to have a textured surface that is an uneven surface. As a result, the light reflectance at the upper surface of the semiconductor substrate 110 is reduced, and a plurality of incidence and reflection operations are performed on the uneven surface, so that light is trapped inside the solar cell 1, thereby increasing light absorption. The efficiency of the solar cell 1 is improved.

The anti-reflection film 130 is positioned on the incident surface of the semiconductor substrate 110 and may be formed of a hydrogenated silicon nitride film (SiNx: H) or the like. The anti-reflection film 130 reduces the reflectance of light incident on the solar cell 1 and increases the selectivity of a specific wavelength region, thereby increasing the efficiency of the solar cell 1.

The emitter portions 120 are spaced apart from each other in the rear surface facing the front surface of the semiconductor substrate 110 and extend in parallel with each other. There may be a plurality of emitters 120 as described above, and the plurality of emitters 120 may have a high concentration of a second conductivity type, for example, p-type impurities, which is opposite to the conductivity type of the semiconductor substrate 110. And a pn junction with the substrate 100. Therefore, the emitter unit 120 includes impurities of trivalent elements such as boron (B), gallium (Ga), indium (In), and the like. The plurality of emitters 120 may be formed by containing a high concentration of p-type impurities p ++, which is a second conductivity type opposite to the conductivity type of the crystalline silicon semiconductor substrate 110, through a diffusion process.

The rear electric field unit 140 may be provided in plural inside the rear surface of the semiconductor substrate 110. The rear electric field unit 140 may be spaced apart in parallel with the plurality of emitter units 120 and extend in the same direction as the plurality of emitter units 120. have. Thus, as shown in FIGS. 1 and 2, the plurality of emitter portions 120 and the plurality of rear electric field portions 140 are alternately positioned on the rear surface of the semiconductor substrate 110.

The plurality of rear electric field parts 140 are impurities, for example, n ++ parts, in which impurities of the same conductivity type as those of the semiconductor substrate 110 are contained at a higher concentration than the semiconductor substrate 110. The plurality of rear electric field parts 140 may be formed by containing a high concentration of impurities (n ++) having the same conductivity type as that of the crystalline silicon semiconductor substrate 110 through a diffusion process.

As a result, a potential barrier is formed due to a difference in impurity concentration between the semiconductor substrate 110 and the plurality of rear electric field parts 140, and thus, holes moved to the rear electric field part 140 are prevented from moving toward the second electrode 141. As a result, the amount of electrons and holes recombined and disappears in the vicinity of the plurality of second electrodes 141 is reduced.

As such, when the plurality of rear electric field units 140 are included in the solar cell 1, the plurality of second electrodes 141 may be electrically connected to the semiconductor substrate 110 via the rear electric field unit 140.

As such, electrons, which are charges generated by light incident on the semiconductor substrate 110 due to a built-in potential difference due to a pn junction formed between the semiconductor substrate 110 and the plurality of emitter portions 120, are formed. Hole pairs are separated into electrons and holes, electrons move toward n-type and holes move toward p-type. Therefore, when the semiconductor substrate 110 is n-type and the plurality of emitter portions 120 are p-type, the separated holes move toward each emitter portion 120 and the separated electrons move toward the plurality of rear electric field portions 140. do.

Since each emitter portion 120 forms a pn junction with the semiconductor substrate 110, unlike the present embodiment, when the semiconductor substrate 110 has a p-type conductivity type, the plurality of emitter portions 120 are n-type. It has a conductivity type of. In this case, the separated electrons move toward the plurality of emitter units 120, and the separated holes move toward the plurality of rear electric fields 140.

The plurality of first electrodes 121 are physically and electrically connected to the plurality of emitter units 120, respectively, and extend along the plurality of emitter units 120.

The patterns of the plurality of first electrodes 121 may be formed along the patterns of the emitter unit 120. Accordingly, the width of the emitter portion 120 may increase in a portion where the width of the first electrode 121 increases, and the width of the emitter portion 120 may also decrease in a portion where the width of the first electrode 121 decreases.

In addition, the plurality of second electrodes 141 are physically and electrically connected to the semiconductor substrate 11 through the rear electric field unit 140, respectively, and extend along the plurality of rear electric field units 140.

The patterns of the plurality of second electrodes 141 may be formed along the pattern of the rear electric field unit 140. In the portion where the width of the second electrode 141 increases, the width of the rear electric field unit 140 also increases, and in the portion where the width of the second electrode 141 decreases, the width of the rear electric field unit 140 may also decrease.

Here, the first electrode 121 and the second electrode 141 are physically spaced apart from each other and electrically isolated from each other on the rear surface of the semiconductor substrate 110.

Accordingly, the first electrode 121 formed on the emitter part 120 collects the charges, for example, holes, which are moved toward the emitter part 120, and the second electrode formed on the rear field part 140. 141 collects charges, for example electrons, which have moved toward the corresponding backside field 140.

As such, holes collected through the first electrode 121 and electrons collected through the second electrode 141 are used as power of the external device through an external circuit device.

As described above, the solar cell 1 having the back junction structure is a solar cell in which the first electrode 121 and the second electrode 141 are positioned on the rear surface of the semiconductor substrate 110 to which light is not incident. same.

When light is irradiated to the solar cell 1 and passes through the anti-reflection film 130 to be incident on the semiconductor substrate 110, electron-hole pairs are generated in the semiconductor substrate 110 by light energy. At this time, since the surface of the semiconductor substrate 110 is a texturing surface, the light reflectivity on the entire surface of the semiconductor substrate 110 is reduced, and incident and reflection operations are performed on the texturing surface to increase light absorption, thereby increasing the efficiency of the solar cell 1. This is improved. In addition, the reflection loss of light incident on the semiconductor substrate 110 by the anti-reflection film 130 is reduced, so that the amount of light incident on the semiconductor substrate 110 is further increased.

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 holes move toward a plurality of emitter portions 120 having a p-type conductivity type, and the electrons are n-type Movement toward the plurality of rear electric field portions 140 having the conductivity type is collected by the first electrode 121 and the second electrode 141, respectively. When the first electrode 121 and the second electrode 141 are connected with a conductive wire, a current flows, which is used as power from the outside.

In this case, since the rear electric field unit 140 containing the same conductivity type impurities as the semiconductor substrate 110 in a high concentration is located on the rear surface of the semiconductor substrate 110, hole movement to the front and rear surfaces of the semiconductor substrate 110 is prevented. Is disturbed. As a result, the electrons and holes are recombined and extinguished in the rear surface of the semiconductor substrate 110, and the efficiency of the solar cell 1 is further improved.

A plurality of such solar cells 1 may be formed in one module, and the plurality of solar cells 1 may be electrically connected in series with each other through a connection part connecting the plurality of solar cells to each other or may be connected in parallel. .

When connected in series, it is possible to increase the output voltage output from one solar cell module formed of a plurality of solar cells (1), and when connected in parallel, it is possible to increase the output current output from one solar cell module. .

Up to now, the semiconductor substrate 110 is a single crystal silicon semiconductor substrate 110 and the emitter portion 120 and the rear electric field portion 140 have been described as an example of the diffusion process, but the emitter portion 120 will be described below. And a back junction hybrid solar cell 2 formed by laminating an amorphous silicon layer on the back field unit 140 will be described.

However, in the back junction hybrid solar cell as described above, the arrangement of the first electrode 121 and the second electrode 141 formed on the back surface of the semiconductor substrate 110 may be applied in the same manner as the back junction solar cell 1. have.

Hereinafter, various embodiments will be described with reference to FIGS. 3 to 8. In these embodiments, the same reference numerals are used to refer to the components shown in Figs. 1 and 2, and the detailed description thereof will be omitted.

3 and 4, the same reference numerals denote the same elements as those shown in FIGS. 1 and 2, and detailed descriptions thereof will be omitted. Therefore, the difference between the solar cell 1 shown in FIGS. 1 and 2 and the solar cell 2 of this example is as follows. In the solar cell 2 of this example, the plurality of emitter portions 120 and the plurality of rear surfaces are shown. The step 140 is made of a material different from the solar cell 1 of FIGS. 1 and 2, such as amorphous silicon. Therefore, the emitter unit 120 and the substrate 110 form a heterojunction unlike the solar cell 1 of FIGS. 1 and 2.

Therefore, the pattern of the first electrode 121 and the second electrode 141 of the back junction hybrid solar cell 2 is the pattern of the first electrode 121 and the second electrode 141 of the solar cell 1 of the IBC structure. It may be formed in the same manner as the pattern.

The pattern of the first electrode 121 and the second electrode 141 of the MWT solar cell 3 will be described in more detail below with reference to FIG. 9.

Referring to FIG. 5, the semiconductor substrate 110 of the MWT solar cell 3 includes a plurality of via holes 181 penetrating through the semiconductor substrate 110. The plurality of via holes 181 are formed in the semiconductor substrate 110 at a portion where the plurality of front electrodes 123 and the first electrodes 121 intersect with each other.

Since the rest of the MWT solar cell 3 is similar to the solar cell of the previous example, other explanations are omitted.

In addition, the patterns of the first electrode 121 and the second electrode 141 of the MWT solar cell 3 may include the first electrode 121 of the solar cell 1 having an IBC structure and the solar cell 2 having a back junction hybrid structure. ) And the second electrode 141 may be formed in the same pattern.

As shown in FIGS. 7 and 8, the EWT solar cell 4 is the same as the MWT solar cell 3, and the emitter portion 120 is formed in the semiconductor substrate 110 as shown in FIGS. 7 and 8. It may be formed in the incident surface, in the semiconductor substrate 110 in the via hole 181, and in the rear surface of the semiconductor substrate 110. The emitter unit 120 forms a p-n junction with the semiconductor substrate 110.

The EWT solar cell 4 has a structure in which the first electrode 121 and the second electrode 141 formed on the rear surface of the EWT solar cell 4 extend in the upper portion of the rear surface of the semiconductor substrate 110. It may be the same as the battery.

Hereinafter, the first electrode 121 and the second electrode 141 formed on the rear surface of the solar cell having various structures described above will be described.

9 is a view for explaining in more detail an example of the pattern of the first electrode and the second electrode in the solar cell according to the present invention, Figure 10 is for comparison with the first electrode and the second electrode according to the present invention Fig. 1 is a diagram briefly showing the first and second electrodes of different patterns.

As described above, the solar cells to which the patterns of the first electrode 121 and the second electrode 141 shown in FIG. 9 are applied may be applied to all of the solar cells described with reference to FIGS. 1 to 8.

In addition, the patterns of the first electrode 121 and the second electrode 141 illustrated in FIG. 9 may include the emitter unit 120 disposed on the rear surface of the semiconductor substrate 110 in addition to the solar cells described with reference to FIGS. 1 to 8. In all cases, this may apply.

Therefore, hereinafter, it will be described on the premise that all of the above-described solar cells of various structures are applied without any special description.

As shown in FIG. 9, a solar cell according to the present invention has a bus bar electrode electrically connecting a plurality of first electrodes 121 to each other or a plurality of second electrodes 141 electrically connected to a rear surface of a semiconductor substrate 110. There is no In addition, the emitter portion 120 having the same pattern as the plurality of first electrodes 121 and having substantially the same width as the plurality of first electrodes 121 between the plurality of first electrodes 121 and the semiconductor substrate 110. ) Is formed, and the plurality of second electrodes 141 and the semiconductor substrate 110 is the same pattern as the plurality of second electrodes 141, the back surface substantially the same as the plurality of second electrodes 141 The electric field unit 140 is formed.

That is, in the solar cell according to the present invention, as shown in FIG. 10, the first bus bar electrode 125 or the plurality of second electrodes 141 electrically connecting the plurality of first electrodes 121 to each other. There is no second busbar electrode 145 to connect electrically.

As in the present invention, when there are no busbar electrodes electrically connecting the plurality of first electrodes 121 or the plurality of second electrodes 141 to each other on the rear surface of the semiconductor substrate 110, electrical shadowing loss ) Can be reduced to maximize the photoelectric conversion efficiency of the solar cell.

Here, the electrical shadowing loss is referred to as an electric shadowing loss when the distance between the carrier generated in the semiconductor substrate 110 and the emitter portion 120 by the light incident from the outside is too large, the carrier is Emmy Since it does not move properly to the rotor part 120, the carrier collection amount of the first electrode 121 connected to the emitter part 120 is lowered, which means that the photoelectric conversion efficiency of the solar cell is lowered.

Typically, the first electrode 121 is formed in the same pattern as the emitter unit 120 on the emitter unit 120, the second electrode 141 is the rear electric field unit 140 on the rear electric field unit 140 It is formed in the same pattern as).

Accordingly, the emitter unit 120 having the same pattern as the first electrode 121 and the first busbar electrode 125 is disposed below the plurality of first electrodes 121 and the first busbar electrode 125 as shown in FIG. 10. ) Is formed, and the rear electric field unit 140 having the same pattern as the second electrode 141 and the second busbar electrode 145 is formed below the plurality of second electrodes 141 and the second busbar electrode 145. ) Is formed.

The reason why the first busbar electrode 125 and the second busbar electrode 145 are formed as shown in FIG. 10 is that the contact area between the interconnector and each solar cell is increased by increasing the contact area with the interconnector connecting the solar cells to each other. This is to minimize the resistance.

However, in order to minimize contact resistance with the interconnector as shown in FIG. 10, when the second busbar electrode 145 having a relatively large area and a long distance to the emitter part 120 is formed, the second busbar electrode ( The carrier generated in the semiconductor substrate 110 positioned below the 145 has a relatively long moving distance to the emitter portion 120, and the carrier generated at the bottom of the second busbar electrode 145 disappears by recombination. The chances of becoming relatively high.

Therefore, as shown in FIG. 10, when the second busbar electrode 145 is formed to have a relatively large area and a long distance to the emitter part 120 to minimize contact resistance with the interconnector, the second busbar The area occupied by the electrode 145 causes a decrease in photoelectric conversion efficiency.

However, as shown in FIG. 9, the patterns of the emitter part 120 and the rear electric field part 140 are formed to alternate with each other, and each of the patterns of the first electrode 121 and the second electrode 141 is formed in the emi. The semiconductor substrate is formed in the same manner as the pattern of the terminator 120 and the rear electric field unit 140, and does not form a bus bar electrode connecting the first electrode 121 to each other or the second electrode 141. Since the distance the carrier moves in most of the region 110 can be minimized, the photoelectric conversion efficiency of the solar cell is further improved.

In addition, as shown in FIG. 9, when the plurality of first electrodes 121 and the plurality of second electrodes 141 according to the present invention extend toward one side of the semiconductor substrate 110 in parallel with each other, The distance D1 from the ends of the plurality of first electrodes 121 to one side of the semiconductor substrate 110 is the distance D1 from the ends of the plurality of second electrodes 141 to one side of the semiconductor substrate 110. May be the same as).

As described above, the emitter unit 120 is formed without forming the busbar electrode and forming the plurality of first electrodes 121 and the plurality of second electrodes 141 in parallel with each other toward one side surface of the semiconductor substrate 110. The distance D1 from the end of the first electrode 121 connected to the end of one side of the semiconductor substrate 110 and the end of the second electrode 141 connected to the rear electric field unit 140 from the end of the semiconductor substrate 110. When the distances D1 to the end of one side of the same are formed to be the same, the carriers collected by the second electrode 141 as well as the carriers collected by the first electrode 121 also in the outer portion of the semiconductor substrate 110. Since the travel distance can be minimized, the photoelectric conversion efficiency of the solar cell can be maximized.

Here, the carrier which affects the photoelectric conversion efficiency of the solar cell is a carrier collected by the first electrode 121 rather than a carrier collected by the second electrode 141, so that the width W121 of the first electrode 121 is determined. The width of the second electrode 141 may be greater than that of the width W141.

In addition, in order to maximize the photoelectric conversion efficiency of the solar cell, it is important that the first electrode 121 and the second electrode 141 are alternately arranged as shown in FIG. 9, and the photoelectric conversion efficiency of the solar cell is one. The smaller the sum P1 of the widths of one second electrode 141 immediately adjacent to the first electrode 121 is increased, the smaller the width P2 of one immediately adjacent second electrode 141 is. The more the photoelectric conversion efficiency is further increased.

So far, the structure of the solar cell and the patterns of the first electrode 121 and the second electrode 141 have been described. Hereinafter, a structure in which the solar cells according to the present invention are connected to each other through an interconnector will be described.

11 to 14 are views for explaining an example of the solar cell module and the interconnector according to the present invention, when the solar cell according to the present invention has a pattern of the first electrode and the second electrode according to FIG.

FIG. 11 is a view of a solar cell module in which a first solar cell S1 and a second solar cell S2 according to the present invention are connected to each other by an interconnector 200, and FIG. 12 is according to the present invention. FIG. 13 is a view for explaining an example of the interconnector 200, and FIG. 13 is a side view of the solar cell module taken along the line III-XIII in FIG. 11, and FIG. 14 is an enlarged view of portions A and B in FIG. to be.

11 and 13, the solar cell module according to the present invention includes a semiconductor substrate 110S1 and 110S2, an emitter part (not shown), a plurality of first electrodes 121S1 and 121S2, and a plurality of second electrodes. A first solar cell including 141S1 and 141S2, but without a busbar electrode electrically connecting the plurality of first electrodes 121S1 and 121S2 to each other or electrically connecting the plurality of second electrodes 141S1 and 141S2 to each other; (S1), the second solar cell (S2) and the interconnector 200.

Here, the first solar cell S1 and the second solar cell S2 may correspond to solar cells having various structures described above, and the semiconductor substrate 110, the emitter unit 120, and the rear electric field unit of each solar cell. The description of the 140, the plurality of first electrodes 121, and the plurality of second electrodes 141 are the same as described above, and thus description thereof will be omitted.

The interconnector 200 is formed in a direction crossing the plurality of first electrodes 121S1 and 121S2 and the plurality of second electrodes 141S1 and 141S2, as shown in FIG. 11, and as illustrated in the first embodiment. A plurality of interconnectors 200 connecting the cells S1 and the second solar cells S2 may be formed.

The interconnector 200 electrically connects the plurality of first electrodes 121S1 of the first solar cell S1 and the plurality of second electrodes 141S2 of the second solar cell S2 to each other in series or in a first manner. The plurality of second electrodes 141S1 of the solar cell S1 and the plurality of first electrodes 121S2 of the second solar cell S2 are electrically connected in series to each other, so that the first solar cell S1 and the second sun are electrically connected. The battery S2 functions to be connected in series with each other, and a plurality of insulating layers are formed on a part of a surface in contact with the first solar cell S1 and the second solar cell S2 in each of these interconnectors. do.

More specifically, first look at an example of the interconnector 200 according to the present invention, as shown in FIG.

As shown in FIG. 12, the interconnector 200 according to the present invention may include a conductive layer 210, an insulating layer 230, and a base layer 240.

Here, the conductive layer 210 functions to electrically connect the first solar cell S1 and the second solar cell S2 to each other in series, and may include a cell conductive material.

Specifically, as shown in FIG. 13, the conductive layer 210 includes a plurality of first electrodes 121S1 in the first solar cell S1 and a plurality of second electrodes 141S2 in the second solar cell S2. Can be electrically connected to each other. Although not shown, the conductive layer 210 electrically connects the plurality of second electrodes 141S1 in the first solar cell S1 and the plurality of first electrodes 121S2 in the second solar cell S2. It is also possible.

As illustrated in FIG. 12, the conductive layer 210 may include a plurality of first conductive layers 213 and a plurality of first conductive layers 213 in contact with a plurality of first electrodes or a plurality of second electrodes, respectively. The second conductive layer 211 may be electrically connected to each other. Here, the first conductive layer 213 and the second conductive layer 211 may include a conductive material of the same material to minimize contact resistance.

Here, the length D213 of the first conductive layer 213 is in contact with the first conductive layer 213 in order to maximize the contact area when contacting the first electrode 121 or the second electrode 141. It may be formed to be the same as or wider than the width of the first electrode or the second electrode.

Therefore, as shown in FIG. 14, in the portion A in contact with the interconnector 200 and the first solar cell S1, the length D213A of the first conductive layer 213 is equal to that of the first conductive layer 213. The width of the first electrode 121S1 may be wider than the width W121S1, and the length D213B of the first conductive layer 213 may be formed at a portion B that contacts the interconnector 200 and the second solar cell S2. ) May be wider than the width W141S2 of the second electrode 141S2 which is in contact with the first conductive layer 213.

In addition, as shown in FIG. 12, the insulating layer 230 is a portion of the upper portion of the conductive layer 210, for example, a portion in which the first conductive layer 213 is not formed on the second conductive layer 211. And a first electrode 121 and a second electrode 141 immediately adjacent to each other to prevent an electrical short. Here, the thickness of the insulating layer 230 and the thickness of the first conductive layer 214 may be the same.

To this end, the length D230 of the insulating layer 230 may be formed to be wider than the width of the first electrode or the second electrode in contact with the insulating layer 230.

Thus, as shown in FIG. 14, in the portion A in contact with the interconnector 200 and the first solar cell S1, the length D230A of the insulating layer 230 is in contact with the insulating layer 230. It may be wider than the width W141S1 of the electrode 141S1, and the length D230B of the insulating layer 230 is the insulating layer 230 in the portion B that contacts the interconnector 200 and the second solar cell S2. ) May be formed to be wider than the width W121S2 of the first electrode 121S2.

12, the length D213 of the first conductive layer 213 of the interconnector 200 and the length D230 of the insulating layer 230 are shown to be the same, but differently from among the interconnectors 200. The length D213 of the first conductive layer 213 is in part longer than the length D230 of the insulating layer 230, and the length of the first conductive layer 213 in at least a portion of the remaining portions of the interconnector 200 ( D213 may be shorter than the length D230 of the insulating layer 230.

For example, as illustrated in FIG. 14, a length D213A of at least one of the plurality of first conductive layers 213 in contact with the first solar cell S1 may be in contact with the first solar cell S2. At least one of the plurality of first conductive layers 213 in contact with the second solar cell S2 is longer than the length D230A of the insulating layer 230 of the second solar cell ( At least one of the plurality of insulating layers 230 in contact with S2 may be shorter than the length D230B. In addition, as shown in FIG. 12, the base layer 240 may have no insulating layer 230 formed thereon. It is formed on the opposite side of the conductive layer 210, it may be made of an insulating material. The base layer 240 may be omitted when the interconnector 200 is formed in the solar cell module.

As described above, the structure of the interconnector 200 according to the present invention may be referred to as an optimal structure that may be applied to a solar cell having no busbar electrode structure as described above. In addition, since the plurality of solar cells are arranged in a row, the interconnector 200 may be continuously adhered to the rear surface of the solar cell, thereby simplifying the process, thereby reducing the process time.

9 to 14 illustrate that the first electrode 121 or the second electrode 141 extends from the top of the rear surface of the semiconductor substrate 110 with the same width, but considers the contact resistance with the interconnector 200. Thus, the first electrode 121 or the second electrode 141 may have different widths depending on the length.

15 is a view for explaining another example of the pattern of the first electrode and the second electrode in the solar cell according to the present invention in more detail, Figure 16 is a solar cell according to the present invention the first electrode and the It is a figure for demonstrating an example of the solar cell module which concerns on this invention when it has a pattern of a 2nd electrode.

As shown in FIG. 15, in the solar cell according to the present invention, the patterns of the first electrode 121 and the second electrode 141 may include the first electrode 121 or the first electrode in consideration of contact resistance with the interconnector 200. The two electrodes 141 may have different widths depending on the length.

15 may be applied to all of the solar cells described with reference to FIGS. 1 to 8, and the structure of the solar cell is the same as described above. Therefore, hereinafter, the description of the remaining portions except for the patterns of the first electrode 121 and the second electrode 141 will be omitted.

In addition, in the foregoing description, since the patterns of each of the first electrode 121 and the second electrode 141 are formed according to the respective patterns of the emitter part 120 and the rear electric field part 140, the parts of the first electrode 121 and the second electrode 141 are not shown at 15. Although not shown, each pattern of the emitter unit 120 and the rear electric field unit 140 will also be described below on the assumption that the patterns of the first electrode 121 and the second electrode 141 are the same.

As shown in FIG. 15, each of the plurality of first electrodes 121 includes a first portion 121a having a first width and at least one second portion 121b having a second width smaller than the first width. can do.

In addition, each of the plurality of second electrodes 141 may include at least one third portion 141a having a third width and at least one fourth portion 141b having a fourth width greater than the third width. In addition, in the same solar cell, the first portion 121a of the plurality of first electrodes 121 is formed at a portion of the plurality of second electrodes 141 that corresponds to the third portion 141a, and the plurality of first electrodes 121a. In each of the electrodes 121, the second portion 121b may be formed at a portion of the plurality of second electrodes 141 that corresponds to the fourth portion 141b.

As shown in FIG. 15, the formation of the first electrode 121 and the second electrode 141 while omitting the busbar electrode minimizes the above-described electrical shadowing loss and simultaneously with the interconnector 200. Since the contact resistance can be minimized, there is an effect of further improving the photoelectric conversion efficiency of the solar cell.

More specifically, each of the plurality of first electrodes 121 may have a relatively wide first portion 121a may be in contact with the interconnector 200 for electrically connecting the solar cells to each other. Each of the fourth portions 141b having a relatively large width 141b may be in contact with the interconnector 200 that electrically connects the solar cells to each other.

In addition, as illustrated in FIG. 15, the length L121a of the first portion 121a having a relatively large width in the first electrode 121 may be the fourth portion (which has a relatively large width in the second electrode 141). It can be made larger than the length L141b of 141b). In this way, the area occupied by the emitter in the total area of the solar cell rear surface can be maximized, and the efficiency of the solar cell can be further maximized.

Here, even when the patterns of each of the first electrode 121 and the second electrode 141 are the same as in FIG. 15, the interconnector 200 described in FIG. 12 may be used in the same manner to connect the solar cells to each other.

FIG. 16A illustrates the first solar cell S1 and the second solar cell S2 connected to each other, and FIG. 16B illustrates an interconnector used in FIG. 16A. An example is seen from the cross section.

More specifically, as shown in FIG. 16A, the interconnector 200 according to the present invention includes a first portion 121a of the first solar cell S1 and a fourth portion of the second solar cell S2. The portions 141b may be electrically connected to each other. The structure of the interconnector 200 is the same as described with reference to FIG. 12. However, the length of the conductive layer 210 and the insulating layer 230 in contact with the first solar cell S1 or the length of the conductive layer 210 and the insulating layer 230 in contact with the second solar cell S2 is The width of the first electrode 121 and the second electrode 141 may be changed as the width thereof changes.

For example, lengths L213S1 and L213S2 of the plurality of first conductive layers 213S1 and 213S2 in contact with the first solar cell S1 and the second solar cell S2, as shown in FIGS. 16A and 16B. ) May be longer than the lengths L230S1 and L230S2 of the plurality of insulating layers 230S1 and 230S2 in contact with the first solar cell S1 and the second solar cell S2.

Specifically, as shown in FIGS. 16A and 16B, the first portion 121a of the first solar cell S1 and the fourth portion 141b of the second solar cell S2 in the interconnector 200. The lengths L213S1 and L213S2 of each of the plurality of first conductive layers 213S1 and 213S2 in contact with each other may be formed by the second portion 121b of the first solar cell S1 and the third portion of the second solar cell S2 ( The length of each of the plurality of insulating layers 230S1 and 230S2 in contact with 141a may be longer than that of the lengths L230S1 and L230S2.

In the solar cell module as shown in FIG. 16A, the first electrode 121S1 of the first solar cell S1 contacting the interconnector 200 while maximizing the area occupied by the emitter in the total area of the rear surface of each solar cell. And by maximizing the area of the second electrode (141S2) of the second solar cell (S2), while minimizing the above-mentioned electrical shadowing (electrical shadowing loss), which can be collected by the emitter unit 120 in each part of the solar cell The amount of the carrier can be maximized, and the contact resistance of the interconnector 200 can be minimized, thereby further maximizing the efficiency of the solar cell.

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. Accordingly, the embodiments disclosed in the present invention and the accompanying drawings are not intended to limit the technical spirit of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by the embodiments and the accompanying drawings. . The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

Claims

A semiconductor substrate containing a first type of impurity, an emitter portion containing a second type of impurity to form a pn junction with the semiconductor substrate, and a plurality of emitter portions formed on an upper surface of the rear surface of the semiconductor substrate and electrically connected to the emitter portion A first solar cell and a second solar cell including a first electrode and a plurality of second electrodes formed on the rear surface of the semiconductor substrate, the second electrodes being alternately spaced apart from the plurality of first electrodes, and electrically connected to the semiconductor substrate. ; And
The plurality of first electrodes of the first solar cell and the plurality of second electrodes of the second solar cell are electrically connected in series with each other, or the plurality of second electrodes and the second solar cell of the first solar cell. An interconnector comprising a plurality of insulating layers electrically connected in series to each other, wherein a portion of a surface in contact with the first solar cell and the second solar cell includes a plurality of insulating layers;
The interconnector may include a conductive layer of an electrically conductive material electrically connecting the first solar cell and the second solar cell to each other in series;
The plurality of insulating layers formed on the side of the conductive layer to be partially spaced apart from the surface in contact with the first solar cell and the second solar cell to prevent the first and second electrodes immediately adjacent to each other from being short-circuited with each other; ; And
And a base layer formed on an opposite surface of the conductive layer on which the plurality of insulating layers are not formed and containing an insulating material.

delete

The method of claim 1,
The conductive layer is
A plurality of first conductive layers in contact with the plurality of first electrodes or the plurality of second electrodes, respectively;
And a second conductive layer electrically connecting the plurality of first conductive layers to each other.

The method of claim 1,
The length of the plurality of insulating layers is larger than the width of the first electrode or the second electrode in contact with each of the plurality of insulating layers, the solar cell module.

The method of claim 1,
The length of at least one of the plurality of first conductive layers in contact with the first solar cell is longer than the length of at least one of the plurality of insulating layers in contact with the first solar cell and in contact with the second solar cell. The length of at least one of the plurality of first conductive layers is shorter than the length of at least one of the plurality of insulating layers in contact with the second solar cell.

The method of claim 1,
And a thickness of the plurality of first conductive layers in the interconnector is equal to a thickness of the plurality of insulating layers.

The method of claim 3, wherein
Each of the plurality of first electrodes in the first and second solar cells includes a first portion having a first width and at least one second portion having a second width less than the first width,
Each of the plurality of second electrodes in the first solar cell and the second solar cell includes a third portion having a third width and at least one fourth portion having a fourth width greater than the third width,
And wherein the interconnector electrically connects the first portion of the first solar cell and the fourth portion of the second solar cell to each other.

The method of claim 7, wherein
The length of each of the plurality of first conductive layers in contact with the first portion of the first solar cell and the fourth portion of the second solar cell is the second portion and the second portion of the first solar cell. And a length of each of the plurality of insulating layers in contact with the third portion of the solar cell.

An interconnector for electrically connecting a plurality of solar cells to each other,
The interconnector may include a conductive layer of an electrically conductive material electrically connecting the plurality of solar cells in series with each other; And
A plurality of insulating layers partially spaced apart on one surface of the conductive layer to prevent a short circuit; And
And a base layer formed on an opposite surface of the conductive layer on which the plurality of insulating layers are not formed, and containing an insulating material.

delete

The method of claim 9,
The conductive layer is
A plurality of first conductive layers in contact with the plurality of first electrodes or the plurality of second electrodes, respectively;
And a second conductive layer electrically connecting the plurality of first conductive layers to each other.

The method of claim 9,
The thickness of the plurality of first conductive layers in the interconnector is the same as the thickness of the plurality of insulating layers.

The method of claim 11,
At least one of the plurality of first conductive layers is longer than at least one of the plurality of insulating layers.

The method of claim 11,
The length of the first conductive layer in a portion of the interconnector is longer than the length of the insulating layer, and in at least a portion of the remaining portion of the interconnector the length of the first conductive layer is shorter than the length of the insulating layer. Interconnect.