KR101264212B1 - Solar cell and solar cell module - Google Patents

Abstract

The present invention relates to a solar cell. One example of the solar cell includes a substrate having a first conductivity type and having a plurality of regions divided in a first direction, each of the plurality of regions having a second conductivity type different from the first conductivity type A plurality of first electrodes connected to the plurality of emitter portions, a plurality of second electrodes electrically connected to the substrate, a first bus bar connected to the plurality of first electrodes, And a second bus bar connected to the electrode, wherein a plurality of first bus bars located in each of the plurality of regions are connected to each other, and a plurality of second bus bars located in each of the plurality of regions are connected to each other.

Description

SOLAR CELL AND SOLAR CELL MODULE [0002]

The present invention relates to a solar cell and a solar cell module.

Recently, as energy resources such as oil and coal are expected to be depleted, interest in alternative energy to replace them is increasing, and solar cells that produce electric energy from solar energy are attracting attention.

Typical solar cells have a semiconductor portion that forms a p-n junction by different conductive types, such as p-type and n-type, and electrodes connected to semiconductor portions of different conductivity types, respectively.

When light enters the solar cell, a plurality of electron-hole pairs are generated in the semiconductor, and electrons and holes generated by the p-n junction move toward the n-type semiconductor portion and the p-type semiconductor portion, respectively. The transferred electrons and holes are collected by different electrodes connected to the p-type semiconductor portion and the n-type semiconductor portion, respectively, and the electrodes are connected to each other by a wire to obtain electric power.

The technical problem to be solved by the present invention is to improve the efficiency of a solar cell.

A solar cell according to an example of the present invention includes a substrate having a first conductivity type and having a plurality of regions divided in a first direction, each of the plurality of regions having a second conductivity type different from the first conductivity type A plurality of first electrodes connected to the plurality of emitter portions, a plurality of second electrodes electrically connected to the substrate, a first bus bar connected to the plurality of first electrodes, and a plurality of second bus bars connected to the plurality of emitter portions, And a second bus bar connected to the second electrode, wherein a plurality of first bus bars located in each of the plurality of regions are connected to each other, and a plurality of second bus bars located in each of the plurality of regions are connected to each other.

Wherein the plurality of first electrodes and the plurality of second electrodes extend in the same direction, and the first bus bar and the second bus bar extend in a direction different from the plurality of first electrodes and the plurality of second electrodes It is good to stretch.

The first direction may be parallel to the transverse sides of the substrate.

 The plurality of first electrodes and the plurality of first electrodes may extend in the first direction.

 The first bus bar and the second bus bar may extend in a second direction intersecting with the first direction.

The second direction may be parallel to the vertical sides of the substrate.

The first bus bar and the second bus bar located in each area may be positioned adjacent to a first vertical side of each of the areas and a second vertical side facing the first vertical side, respectively.

The plurality of first electrodes and the plurality of second electrodes located in each region may be positioned between the first bus bar and the second bus bar.

The extension lengths of the plurality of first electrodes positioned between the first bus bar and the second bus bar are the same and the extension lengths of the plurality of second electrodes positioned between the first bus bar and the second bus bar are the same can do.

The lengths of the plurality of first electrodes positioned between the first bus bar and the second bus bar are the same, except for the first electrode and the second electrode located at the edge of the substrate, The extension lengths of the plurality of second electrodes located between the two bus bars may be the same.

The solar cell according to the above feature may further include a first connection terminal extending in the first direction from each of the plurality of first bus bars and a second connection terminal extending from the plurality of second bus bars in the first direction The plurality of first bus bars may be connected to each other through the first connection terminal, and the plurality of second bus bars may be connected to each other through the second connection terminal.

The width of the first connection terminal is greater than the width of each of the plurality of first electrodes and the width of the second connection terminal is greater than the width of each of the plurality of second electrodes.

The solar cell may further include a plurality of electric field units having the first conductivity type, and the plurality of second electrodes may be electrically connected to the substrate through the plurality of electric field units.

The plurality of emitter portions, the plurality of first electrodes, the plurality of second electrodes, the plurality of first bus bars, and the plurality of second bus bars may be located on the same side of the substrate.

Wherein the plurality of emitter portions, the plurality of first electrodes, the plurality of second electrodes, the plurality of first bus bars, and the plurality of second bus bars are disposed on the opposite sides of the incident surface of the substrate, And may be located on the surface of the substrate.

The widths of the first electrode and the second electrode may be equal to each other.

The width of the first electrode and the width of the second electrode may be 60 탆 to 3000 탆, respectively.

The widths of the first bus bar and the first bus bar may be the same.

The width of the first bus bar and the second bus bar may be greater than the width of the first electrode and the second electrode.

Each first bus bar and each second bus bar has a width of 1 mm to 10 mm each.

A solar cell module according to another aspect of the present invention includes a plurality of solar cells connected in series, a first protective film disposed on an incident surface of the plurality of solar cells, a second protective film disposed on an opposite side of an incident surface of the plurality of solar cells, And a transparent substrate disposed on the first protective film, wherein each of the plurality of solar cells has a first conductivity type and includes a substrate having a plurality of regions divided in a first direction, Each comprising a plurality of emitter portions having a second conductivity type different from the first conductivity type, a plurality of first electrodes coupled to the plurality of emitter portions, a plurality of second electrodes electrically coupled to the substrate, A first bus bar connected to one electrode, and a second bus bar connected to the plurality of second electrodes, wherein a plurality of first bus bars located in each of the plurality of regions And it connected to a plurality of second bus bar on each of the plurality of regions are connected to each other.

According to this feature, the solar cell is divided into a plurality of regions, and first and second electrodes and first and second bus bars for collecting electric charge generated in each region are formed in each region, 1 and the movement distance of the charge moving to the second bus decreases. This reduces the amount of charge lost during the first and second bus bar movements along the first and second electrodes in each region, thereby improving the efficiency of the solar cell.

1 is a partial perspective view of a solar cell according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the solar cell shown in FIG. 1 taken along line II-II.
FIG. 3 is a view showing an example of the arrangement form of the first electrode portion and the second electrode portion formed on the rear surface of the substrate in the solar cell shown in FIGS. 1 and 2. FIG.
FIG. 4 is a view showing another example of the arrangement form of the first electrode part and the second electrode part formed on the rear surface of the substrate in the solar cell shown in FIGS. 1 and 2. FIG.
5 is a schematic perspective view of a solar cell module according to an embodiment of the present invention.
6 is a view showing a connection structure of a plurality of solar cells when a plurality of solar cells according to an embodiment of the present invention are connected to fabricate the solar cell module.

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

In the drawings, the thickness is enlarged to clearly represent the layers and regions. When a layer, film, region, plate, or the like is referred to as being "on" another portion, it includes not only the case directly above another portion but also the case where there is another portion in between. Conversely, when a part is "directly over" another part, it means that there is no other part in the middle. Further, when a certain portion is formed as "whole" on another portion, it means not only that it is formed on the entire surface of the other portion but also that it is not formed on the edge portion.

First, a solar cell according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3. FIG.

1 to 3, the solar cell 11 according to the present embodiment includes a substrate 110, an incident surface (hereinafter referred to as a 'front surface') that is a surface of the substrate 110 on which light is incident , A front electric part 171 located on the front protective part 191, an antireflective part 130 positioned on the front electric part 171, a substrate (not shown) on the opposite side of the incident surface, A plurality of emitter regions 121 located on the surface of the substrate 110 (hereinafter referred to as a back surface), a plurality of emitter regions 121 located on the rear surface of the substrate 110, A first electrode unit 140 connected to the plurality of emitter units 121 and a plurality of backside units 172 connected to the plurality of emitter regions 121, And a second electrode unit 150.

Generally, light is not incident on the rear surface of the substrate 110, but light may be incident on the rear surface of the substrate 110 as the case may be. In this case, the amount of light incident through the rear surface of the substrate 110 is much smaller than the amount of light incident through the front surface of the substrate 110.

The substrate 110 is a substrate of a first conductivity type, for example, a single crystal silicon of n-type conductivity type or a crystalline semiconductor such as polycrystalline silicon. At this time, since the substrate 100 has the n-type conductivity type, the substrate 110 may have a five-valence structure such as N, P, As, May contain impurities of the element.

Alternatively, the substrate 110 may be a p-type conductive type. In this case, the substrate 110 may be formed of a metal such as boron (B), aluminum (Al), gallium (Ga), indium (In) And the like. In yet another embodiment, the substrate 110 may be comprised of a semiconductor material other than silicon.

The front surface of the substrate 110 has a textured surface which is an irregular uneven surface through a texturing process. At this time, the texturing process is performed on the entire front surface of the substantially flat substrate 110. 1, only the edge portion of the substrate 110 is shown as an uneven surface, and the front protective portion 191, the front electric portion 171, and the anti-reflection portion 130, which are positioned thereon, Respectively. The entire front surface of the substrate 110 has a rough surface and the front surface protective part 191, the front surface electric part 171 and the antireflection part 130 located on the front surface of the substrate 110 also have a rough surface .

As a result, since the front surface of the substrate 110 has the textured surface, the light reflection on the front surface of the substrate 110 is reduced, and the incidence and reflection operations are performed a plurality of times on the surface of the substrate 110, So that the absorption rate of light is increased, so that the efficiency of the solar cell 11 is improved.

The front surface protection portion 191 located on the front surface of the substrate 110 which is an uneven surface may be made of hydrogenated silicon oxide (SiOx: H) or the like.

At this time, the front surface protection unit 191 may be located entirely on the front surface of the substrate 110 or may be positioned on the front surface of the substrate 110 except for the edge portion of the front surface of the substrate 110.

The front surface protection portion 191 is formed by using hydrogen (H) contained in the front surface protection portion 191 to remove defects such as dangling bonds mainly present on the surface of the substrate 110 and its vicinity A passivation function is performed to reduce the amount of charge transferred to the surface of the substrate 110 due to the defect by changing the stable coupling so that the amount of charge lost on the surface of the substrate 110 and its vicinity due to the defect .

The front electric field portion 171 located on the front surface protection portion 191 is formed of an impurity of the first conductive type which is the same conductivity type as the substrate 110 and contains impurities at a higher concentration than the substrate 110, to be.

Therefore, a potential barrier is formed due to a difference in impurity concentration between the substrate 110 and the front electric field portion 171, thereby performing a front electric field function that hinders the hole movement toward the front surface of the substrate 110. Therefore, a front field effect is obtained in which the holes moving toward the front side of the substrate 110 by the front electric field portion 171 are returned to the rear side of the substrate 110 by the potential barrier, The output amount of the holes output to the external device through the rear surface increases and the amount of charges lost due to recombination or defects at the front surface of the substrate 110 decreases.

The antireflective portion 130 located on the front electric field portion 171 is made of a hydrogenated silicon nitride film (SiNx: H) or the like. The reflection preventing part 130 reduces the reflectivity of the light incident on the solar cell 11 and increases the selectivity of the specific wavelength area to increase the efficiency of the solar cell 11. [ In this embodiment, the anti-reflection film 130 has a single film structure but may have a multi-layer structure such as a double film structure.

In this embodiment, at least one of the front surface protection part 191, the front electric part 171, and the anti-reflection part 130, which are disposed on the front surface of the substrate 110, may be omitted.

The plurality of emitter portions 121 located in the rear surface of the substrate 110 are spaced apart from each other and extend in a predetermined direction (e.g., a first direction).

The plurality of emitter portions 121 contain a second conductive type, for example, a p-type impurity (p ++) opposite to the conductive type of the substrate 110, 110) to form a pn junction. Therefore, the emitter section 121 includes impurities of a trivalent element.

The plurality of emitter portions 121 may be formed by diffusing impurities of a second conductivity type (e.g., p-type) into the substrate 110 through a diffusion process at a concentration higher than that of the substrate 110.

A plurality of rear electric sections 172 located in the rear surface of the substrate 110 are separated from the plurality of emitter sections 121 and extend in the same direction as the plurality of emitter sections 121 in parallel with each other.

Accordingly, as shown in Figs. 1 and 2, a plurality of emitter portions 121 and a plurality of rear electric sections 172 are alternately arranged on the rear surface of the substrate 110. [

The plurality of rear electric fields 172 are impurities, for example, n ++ parts, which contain impurities of the same conductivity type as that of the substrate 110 at a higher concentration than the substrate 110.

The plurality of rear electric fields 172 may be formed by diffusing impurities of the first conductivity type (e.g., n-type) into the substrate 110 through a diffusion process at a concentration higher than that of the substrate 110.

As a result, a potential barrier is formed due to a difference in impurity concentration between the substrate 110 and the plurality of rear electric fields 172, so that the holes, which have moved toward the rear electric field 172, The movement toward the electrode 151 is disturbed, and the amount of recombination of electrons and holes near the second electrode 151 and disappearing is reduced.

Due to the built-in potential difference due to the pn junction formed between the substrate 110 and the plurality of emitter portions 121, electrons and holes, which are charges generated by the light incident on the substrate 110, Type semiconductor region and the p-type semiconductor region, respectively. Therefore, when the substrate 110 is n-type and the plurality of emitter portions 121 are p-type, the holes move toward the respective emitter portions 121 and electrons move toward the respective rear electric portions 172.

Each emitter section 121 forms a pn junction with the substrate 110. Therefore, when the substrate 110 has a p-type conductivity type, unlike the present embodiment, the plurality of emitter sections 121 are n-type conductivity Type. In this case, the electrons move toward the plurality of emitter sections 121 and the holes move toward the plurality of rear electric field sections 172.

The rear surface protection portion 192 is located on the rear surface of the substrate 110 and has an opening portion for exposing a part of each emitter portion 121 and an opening portion for exposing a part of each rear electric portion 172. This allows the rear shield 192 to be directly above the backside of the substrate 110 where the emitter portion 121 and the backside electrical portion 172 are not located, on a portion of each emitter portion 121, 172, < / RTI >

At this time, the opening portion exposing a part of each emitter section 121 has a stripe shape extending long from the emitter section 121 in the extending direction (that is, the first direction) of the emitter section 121 , The opening that exposes a part of each rear electric section 172 has a stripe shape extending long along the extending direction of the rear electric section 172 on each rear electric section 172.

Like the front surface protection unit 191, the rear surface protection unit 192 is formed of a hydrogenated silicon oxide film (SiOx: H) or the like and changes the defects present on the back surface and the vicinity of the substrate 110 into stable bonding, 110 is reduced due to the defect.

3, the first electrode unit 140 includes a plurality of first electrodes 141 connected to the plurality of emitter units 121, a plurality of first electrodes 141 connected to the plurality of first electrodes 141, The first bus bar 142 of FIG.

The plurality of first electrodes 141 are physically and electrically connected to the respective emitter sections 121 exposed through the openings and extend along the plurality of emitter sections 121 on the plurality of emitter sections 121 .

The plurality of first electrodes 141 collects charges, for example, holes, which have migrated toward the emitter section 121.

As shown in FIG. 3, the plurality of first bus bars 142 extend in a direction (for example, a second direction) intersecting with the plurality of first electrodes 141, 141). Therefore, as shown in FIG. 3, the plurality of first electrodes 141 extending in the first direction extend from the first bus bars 142 extending in the second direction.

The plurality of first bus bars 142 collect the charges collected by the plurality of first electrodes 141 and transfer the collected charges in the corresponding directions.

In this case, since the plurality of first bus bars 142 collect the electric charges collected by the plurality of first electrodes 141 intersecting each other and move them in a desired direction, Is larger than the width of the electrode (141).

The second electrode unit 150 includes a plurality of second electrodes 151 connected to the plurality of rear electric units 172 and a plurality of second bus bars 152 connected to the plurality of second electrodes 151 .

A plurality of second electrodes 151 are physically and electrically connected to each of the exposed backside electrical components 172 through the corresponding openings and are electrically connected to the plurality of backside electrical components 172 along the plurality of backside electrical components 172 Extended.

The plurality of second electrodes 151 collect electrons, for example, electrons, which have migrated toward the rear electric field 172.

Similar to the plurality of first bus bars 142, the plurality of second bus bars 152 are electrically and physically connected to the rear electric section 172, as shown in FIG. 3, (For example, a second direction) intersecting with the first electrode 151, and is connected to a plurality of second electrodes 151 that intersect with each other. Therefore, as shown in FIG. 3, the plurality of second electrodes 151 extending in the first direction also extend from the second bus bars 152 extending in the second direction.

The plurality of second bus bars 152 collect the electric charges collected by the plurality of second electrodes 151 and transfer the collected electric charges in the corresponding directions.

The plurality of first bus bars 142 and the plurality of second bus bars 152 are connected to an external device through a conductive film such as a ribbon, and the collected electric charges are output to an external device.

As with the first bus bar 142, the width of each second bus bar 152 is greater than the width of each second electrode 151.

The widths of the first electrode 141 and the second electrode 151 may be the same and the widths of the first bus bar 142 and the second bus bar 152 may be the same. At this time, the widths of the first and second bus bars 142 and 152 may be equal to or larger than the width of the conductive film.

In this example, the width of each of the first electrodes 141 and each of the second electrodes 151 may be about 60 μm to 3000 μm, and the width of each of the first bus bars 142 and the second bus bars 152 The width may be from 1 mm to 10 mm. The width of the conductive film may be 1 mm to 10 mm.

Unlike the present example, the widths of the first electrodes 141 and the second electrodes 151 may be different from each other. For example, holes having a mobility lower than that of electrons may be formed in such a manner that the width of the collecting electrode (for example, the first electrode 141) is larger than the width of the electrode (for example, It can be big. Even in this case, the angular widths of the first and second electrodes 141 and 151 may be about 60 탆 to 3000 탆.

1 and 2, since the rear protective part 192 made of an insulating material is disposed between the adjacent first and second electrodes 141 and 151, the first and second electrodes 141 and 142, The electrodes 151 are electrically separated from each other.

Therefore, it is possible to prevent a short circuit between the adjacent emitter section 121 and the rear electric section 172 to prevent leakage of electric charges and to prevent electric leakage due to electrical interference between the adjacent emitter section 121 and the rear electric section 172 Also prevents loss of charge. As a result, the amount of leakage current of the solar cell 11 is reduced.

1 and 2, each first electrode 141 connected to each emitter section 121 is partially located on the adjacent rear protection section 192 and can partially overlap with the rear protection section 192, Each of the second electrodes 151 connected to the electric system part 172 may be partially overlapped with the rear protection part 192 and partially overlapped with the rear protection part 192. In this case, since the design margin of the first and second electrodes 141 and 151 is increased, the manufacture of the solar cell 11 becomes easier.

The operation of the solar cell 11 according to this embodiment having such a structure is as follows.

The solar cell 11 is irradiated with light and sequentially passes through the antireflection part 130 and the front electric part 171 and the front surface protection part 191 and is incident on the substrate 110, Electron-hole pairs are generated. At this time, since the surface of the substrate 110 is a textured surface, the light reflectivity at the front surface of the substrate 110 is reduced, and the incidence and reflection operations are performed at the textured surface to increase the light absorption rate. do. In addition, the reflection loss of the light incident on the substrate 110 by the anti-reflection unit 130 is reduced, and the amount of light incident on the substrate 110 is further increased.

These electron-hole pairs are separated from each other by the pn junction of the substrate 110 and the emitter section 121, and the holes move toward the plurality of emitter sections 121 having the p-type conductivity type, and electrons move to the n- And then collected by the first electrode 141 and the second electrode 151, respectively. When the first electrode 141 and the second electrode 151 are connected to each other by a conductive line, a current flows and is used as electric power from the outside.

The pn junction of the substrate 110 and the emitter section 121 causes the holes to move toward the emitter section 121 having the p type conductivity type and the electrons to the rear surface electric section 172 having the n type conductivity type And moves to the first bus bar 142 and the second bus bar 152 through the first electrode 141 and the second electrode 151, respectively. When the first bus bar 142 and the second bus bar 152 are connected to each other by a wire, a current flows and is used as electric power from the outside.

Since the first electrode unit 140 and the second electrode unit 150 are located on the rear surface of the substrate 110 opposite to the incident surface (i.e., the front surface), the first electrode unit 140 and the second electrode unit 150 The amount of light incident on the substrate 110 increases as compared to when the substrate 150 is positioned on the front surface of the substrate 110. [ As a result, the efficiency of the solar cell 11 is improved.

At this time, since the front surface protection portion 191 and the rear surface protection portion 192 are disposed on the front surface and the rear surface of the substrate 110, unstable coupling between the front surface and the rear surface of the substrate 110 causes the substrate 110 The amount of charge loss in the vicinity of the surface is reduced and the front electric field portion 171 and the rear electric field portion 172 are located on the front and rear surfaces of the substrate 110, Hole transport is disturbed. As a result, the amount of charges lost due to defects on the rear surface and the front surface of the substrate 110, and the amount of recombination between electrons and holes are eliminated and the efficiency of the solar cell 11 is further improved.

As shown in Fig. 3, the solar cell 11 is divided into a first region G1 and a second region G2, which are two regions.

The first and second regions G1 and G2 are obtained by dividing the first and second regions G1 and G2 in the first direction which is the extending direction of the first and second electrodes 141 and 151. The first and second regions G1 and G2 Is an area obtained when the lateral sides of the substrate 110 are divided in two in Fig. At this time, the lateral sides of the regions G1 and G2 may be substantially the same.

The substrate of the solar cell 11 shown in Fig. 3 is a substrate made of monocrystalline silicon, and all four corners E1-E4 have a chamfer shape. However, when the substrate of the solar cell 110 is made of polycrystalline silicon, the four corners E1-E4 have a shape in which the transverse sides and the vertical sides meet vertically at the respective corners E1-E4 without a chamfer shape do.

As shown in Fig. 3, since the structures of the solar cells shown in Figs. 1 and 2 already exist in the first and second regions G1 and G2, the first and second regions G1 and G2 are separated from each other in the regions G1 and G2, A plurality of emitter sections 121 separated from the plurality of emitter sections 121 and extending in a first direction so as to be spaced apart from each other, a plurality of emitter sections 121 connected to the plurality of emitter sections 121, A plurality of first electrodes 141 extending in a first direction, a plurality of second electrodes 151 connected to a plurality of rear electric units 172 and extending in a first direction, a plurality of first electrodes 141, 141 and a second bus bar 152 connected to the plurality of second electrodes 151 and extending in a second direction. The first bus bar 142 extends in the second direction and the second bus bar 152 extends in the second direction.

Therefore, the present embodiment is a structure in which the substrate 110 of the solar cell 110 is divided into a plurality of regions G1 and G2 and solar cells having the same function and the same structure are designed in the plurality of regions G1 and G2 The solar cell formed in each of the regions G1 and G2 can be referred to as a sub-cell.

3, a first electrode unit 140 having a plurality of first electrodes 141 and a first bus bar 142 disposed on the rear surface of the substrate 110 in each of the regions G1 and G2, The plurality of emitter portions 121 may be formed under the plurality of first electrodes 141. The plurality of emitter portions 121 may include a plurality of second electrodes 151 and a plurality of second bus bars 152, And a plurality of the plurality of rear electric sections 172 exist under the plurality of second electrodes 151.

At this time, the emitter portion 121 existing in the first region G1 and the emitter portion 121 existing in the second region G2 are separated from each other, and the emitter portion 121 existing in the first region G1 and the emitter portion 121 existing in the second region G2 are separated from each other, 172 and the rear electric part 172 existing in the second area G2 are also separated. The emitter portion 121 and the rear electric portion 172 are not located under the first bus bar 142 and the second bus bar 152 located in the regions G1 and G2, have.

In FIG. 3, a front protection unit 191, a front electric field unit 171, and an anti-reflection unit 130 are sequentially disposed on the entire front surface of the substrate 110, as described with reference to FIGS.

As described above, the first electrode unit 140 and the second electrode unit 150, which are disposed in the first and second regions G1 and G2, respectively, have the same configuration.

First, the first and second bus bars 142 and 152 and the first and second electrodes 141 and 151 arranged in the first region G1 will be described.

The first bus bar 142 is connected to the first longitudinal side V1 of the substrate 110 (e.g., the left side of the substrate 110 or the left side of the first region G1) And the second bus bar 152 extends from the first edge E1 chamfered to the second edge E2 in a side-by-side direction (i.e., the second direction) And the first side of the substrate 110 is adjacent to the interface B1 in the direction parallel to the interface B1 of the first area G1 and the second area G2 (or the right side of the first area G1) (E.g., the upper side of the substrate 110) to the second side (H2) of the substrate 110 (e.g., the lower side of the substrate 110).

At this time, a plurality of first electrodes 141 extend in a first direction in the first bus bar 142 and a plurality of second electrodes 151 are formed in the second bus bar 152 And extends in the first direction.

The plurality of first electrodes 141 extending from the first bus bar 142 are electrically and physically separated from the adjacent second bus bar 152 by being positioned adjacent to the second bus bar 152 located on the opposite side A plurality of second electrodes 151 extending from the second bus bar 152 are also electrically and physically separated from and adjacent to the first bus bar 142 located adjacent to the first bus bar 142 have. A plurality of emitter portions 121 and a plurality of rear electric fields 172 extending in the first direction are positioned between the first bus bar 142 and the second bus bar 152 extending in the second direction .

The first electrode 141 and the second electrode 151 are alternately disposed in the first direction and are adjacent to the first electrode 141 and the second electrode 151 in the first direction in the first direction G1, Are electrically and physically separated. Accordingly, the first electrode 141 and the second electrode 151 form a comb.

The structures of the first and second electrodes 141 and 151 and the first and second bus bars 142 and 152 disposed in the second region G2 are similar to the arrangement structure of the first region G1 .

That is, the first bus bar 142 of the second area G2 is aligned in the direction parallel to the interface B1 of the first area G1 and the second area G2 (or the left side of the second area G2) And is adjacent to the second bus bar 142 of the first region G1 and extends from the first transverse side H1 of the substrate 110 to the second transverse side H2 .

The second bus bar 152 of the second region G2 is positioned opposite the first bus bar 142 and is located at a second longitudinal side V2 of the substrate 110 And the fourth edge E4 from the third edge E3 adjacent to the second longitudinal edge V2 in the direction parallel to the second edge G2.

Therefore, in the second region G2, as in the first region G1, the plurality of first electrodes 141 extend at regular intervals in the first bus bar 142, The plurality of second electrodes 151 extend at regular intervals in the second bus bar 152 and extend in the second direction G2 in the first direction. The first bus bar 142 of FIG.

The first electrode 141 and the second electrode 151 adjacent to each other in the first direction are electrically and physically separated from each other and the plurality of first electrodes 141 extending from the first bus bar 142 are electrically connected to the second electrode 141, A plurality of second electrodes 151 separated from a second bus bar 152 located adjacent the longitudinal side V2 and extending from the second bus bar 142 are connected to a first bus And is separated from the bar 142.

Accordingly, in the second region G2, the first electrode 141 and the second electrode 151 also form a comb.

As shown in Fig. 3, the edges E1-E4 of the substrate 110 have a chamfer shape, so that the first electrode 141 located at each corner E1-E4 having a chamfer shape is positioned And the extension length of the second electrode 151 is shorter than the extension length of the second electrode 151 located in the other portion.

However, when the shape of each edge E1-E4 does not have a chamfer shape, the extension lengths of the plurality of first electrodes 141 existing in the regions G1 and G2 are substantially the same, The extension length of the electrode 151 may be substantially the same.

The plurality of first electrodes 141 extend from the first edge E1 and the second edge E2 of the first region G1 and extend from the upper side of the substrate 110, And first electrodes 1411 and 1412 which are positioned adjacent to the lower side of the substrate 110, that is, the second transverse side H2 and are adjacent to the first and second transverse sides H1 and H2, Respectively. The width of each of the first electrodes 1411 and 1412 is larger than the width of the other first electrode 141. Similarly, the plurality of second electrodes 151 also extend from the third edge E3 and the fourth edge E4 of the second area G2, respectively. The first and second transverse edges H1 and H2, And the width of each of the second electrodes 1511 and 1512 is also greater than the width of the second electrode 151.

The width of the first electrodes 1411 and 1412 may be equal to the width of the first bus bar 142 and the width of the second electrodes 1511 and 1512 may be equal to the width of the second bus bar 152 have.

The first electrodes 1411 and 1412 of the first region G1 and the second electrode 1511 1512 of the second region G2 electrically connect a plurality of solar cells 11 to form a plurality of solar cell modules And functions as a connection terminal for connecting two adjacent solar cells 11 when fabricated.

At this time, the first bus bar 142 located in the first region G1 and the first bus bar 142 located in the second region G2 are connected to the connection terminals 1411 and 1412 located in the first region G1 The second bus bar 152 located in the first area G1 and the second bus bar 152 located in the second area G2 are connected to each other in the vicinity of the interface B1 of the second transverse side H2 via the second bus bar 1412, The bus bars 152 are connected to each other in the vicinity of the interface B1 of the first transverse side H1 through one of the connection terminals 1511 and 1512 located in the second area G2.

The first electrode portion 140 located in the first region G1 is electrically and physically connected to the first electrode portion 140 located in the second region G2 and is electrically connected to the first electrode portion G1 in the first region G1. And the second electrode unit 150 is electrically and physically connected to the second electrode unit 150 located in the second area G2.

Since the solar cell 11 is divided into the two regions G1 and G2 and the first electrode portion 140 and the second electrode portion 150 exist in each of the regions G1 and G2, The extended lengths of the first electrodes 141 and the second electrodes 151 located at the first and second substrates G1 and G2 are set such that the area of the substrate 110 is not divided into the plurality of regions G1 and G2, Compared to the case where only one first electrode unit 140 and one second electrode unit 150 are present.

3, since the regions G1 and G2 of the substrate 110 are divided into two portions, the extension length of each of the first electrode 141 and each of the second electrodes 151 is equal to the area of the substrate 110 It is reduced to about 1/2 when it is not divided.

In addition, when the substrate 110 is divided into the plurality of regions G1 and G2, the amount of holes and electrons collected by the first and second electrodes 141 and 151 is set such that the region of the substrate 110 is divided The width of each of the first and second electrodes 141 and 151 can be reduced as compared with the case where the area of the substrate 110 is not divided and the widths of the first and second electrodes 141 and 151, The width of the second bus bar 152 connected to the first electrode 142 and the second electrode 151 may also be reduced. As a result, the formation area of the first electrode unit 140 and the second electrode unit 150 made of a material which causes a high manufacturing cost such as silver (Ag) is reduced, so that the manufacturing cost of the solar cell 11 is reduced do.

In this embodiment, the first bus bar 142 is located on the left side of each of the regions G1 and G2 and the second bus bar 152 is located on the right side of each of the regions G1 and G2, The second bus bar 152 may be positioned on the left side of the areas G1 and G2 and the first bus bar 142 may be positioned on the right side of the areas G1 and G2.

As described above, the lateral side of the substrate 110 is divided into n portions, the region of the substrate 110 is divided into n regions G1 and G2, and the first electrode portion 140 is formed for each of the regions G1 and G2. The first bus bar 142 and the second bus bar 142 are positioned to face each other with a plurality of first and second electrodes 141 and 151 interposed therebetween in the regions G1 and G2 when the second electrode unit 150 and the second electrode unit 150 are positioned. The maximum movement distances D1 and D2 of the holes and electrons respectively moving to the second bus bar 152 are reduced to about 1 / n when the area of the substrate 110 is not divided. Where n is 2, 3, 4, ..., n.

As a result, the series resistance from the plurality of emitter sections 121 to the first electrode section 140 and the series resistance from the plurality of rear electric section 172 to the second electrode section 150 decrease.

Accordingly, the movement distance of charges moving to the corresponding bus bars 142 and 152 in the regions G1 and G2 is reduced, and the amount of electric charges lost during movement to the corresponding bus bar 142 152 is greatly reduced, The amount of charges (for example, holes) moving from the emitter portion 121 to the first bus bar 142 and the amount of charges (e.g., electrons) traveling from the plurality of the rear electric portions 172 to the second bus bar 152, The amount of current (e.g., short-circuit current Jsc) output from the solar cell 11 increases.

3, the width of the first electrode 141 existing in each of the regions G1 and G2 and the width of the second electrode 151 are the same, but they may be different from each other. For example, since the mobility of holes is smaller than the mobility of electrons, the width of the electrode (e.g., the first electrode 141) for collecting holes may be wide. In this case, since the wiring resistance of each electrode for transferring holes is smaller than the wiring resistance of each electrode for transferring electrons, the difference in amount of collected charges due to the difference in the mobility of holes and electrons is compensated.

In this example, the widths of the first electrodes 141 existing in different regions are equal to each other, the widths of the second electrodes 151 existing in different regions are equal to each other, The width of the first bus bar 142 and the width of the second bus bar 152 are the same.

4, the region of the substrate 110 is divided into three regions G1, G2, and G3 as shown in FIG. 4, G3).

3, a plurality of first electrodes 141, 1411 and 1412 and a first bus bar 142 are provided in each of the regions G1, G2 and G3, A second electrode unit 150 having a plurality of second electrodes 151, 1511 and 1512 and a second bus bar 152 is positioned.

The first and second bus bars 142 and 152 located in the respective regions G1, G2 and G3 are positioned facing each other on the left and right sides of the regions G1, G2 and G3, A plurality of first electrodes 141 connected to the first bus bar 142 and a plurality of second electrodes 141 connected to the second bus bar 152 extend in the first direction between the first bus bar 142 and the second bus bar 152, Electrode 151 is present.

The plurality of first electrodes 141 extend from the first bus bar 142 to the second bus bar 152 in the vicinity of the second bus bar 152 and the plurality of second electrodes 151 Extends from the second bus bar 152 to the first bus bar 142 adjacent to the first bus bar 142 and the plurality of first electrodes 141 are separated from the adjacent second bus bar 152 And the plurality of second electrodes 151 are separated from the adjacent first bus bars 142.

  At this time, the first electrode 141 and the second electrode 151 adjacent to each other in the second direction are separated from each other. In the region between the first bus bar 142 and the second bus bar 152, the first electrode 141 And the second electrode 151 are alternately arranged in the second direction.

4, the plurality of first bus bars 142 located in the respective regions G1, G2 and G3 are positioned adjacent to the lower side (second transverse side H2) of the substrate 110 A plurality of second bus bars 152 connected to each other by the first electrode (connection terminal) 1412 and located in each of the regions G1, G2 and G3 are connected to the upper side of the substrate 110 (Connection terminal) 1511 located adjacent to the first electrode (H1).

4, the first bus bar 142 is located on the left side of each of the regions G1, G2 and G3 and the second bus bar 152 is located on the right side of the regions G1, G2 and G3. And the first bus bar 142 is located on the right side of the second bus bar 152. [ The connection positions of the plurality of first bus bars 142 located in the regions G1, G2 and G3 and the connection positions of the plurality of second bus bars 152 located in the regions G1, G2 and G3 are They can be exchanged with each other. For example, unlike FIG. 4, the first bus bars 142 located in the respective regions G1-G3 may be connected to each other near the second transverse side H2 (lower side) of the substrate 110, The second bus bars 152 located at the first side G1-G3 may be connected to each other near the first side H1 (upper side) of the substrate 110. [

As described above, the substrate 110 is divided into three regions G1, G2 and G3, and the first electrode portion 140 and the second electrode portion 150 (not shown) are formed separately in the divided regions G1, G2 and G3, The lengths of the first electrodes 141 and the second electrodes 151 located in the respective regions G1, G2 and G3 are further reduced so that the distance between the first electrode 141 and the second electrode 151 151 and the maximum movement distances D11, D12, D21, and D21 of the charge moving to the first bus bar 142 and the second bus bar 152 in the regions G1, G2, D22, D31, D32) also decrease.

Accordingly, the series resistance between the plurality of emitter portions 121 and the first electrode portion 140 and the series resistance between the plurality of the backside electric portion 172 and the second electrode portion 150 are further reduced.

As a result, the amount of charge moving to the first bus bar 142 and the second bus bar 152 increases, and the first bus bar 142 or the second bus bar 152 Lt; RTI ID = 0.0 > loss) < / RTI >

4, the lengths of the first electrodes 141 and the second electrodes 151 in the leftmost region G1 and the rightmost region G3 of the substrate 110 may be the same, The length of the first electrode 141 and the second electrode 151 existing in the leftmost region G1 is equal to the length of the first electrode 141 and the second electrode 151 existing in the rightmost region G3, Can be the same.

In this embodiment, the region of the substrate 110 is divided into at most three regions G1-G3, but not limited thereto, and is divided into four or more regions according to the size of the substrate 110, The first electrode unit 140 and the second electrode unit 150 may include a plurality of first electrode units 140 and a plurality of second electrode units 150, Are connected to each other.

As described above, the solar cell 11, in which the substrate 110 is divided into a plurality of regions and the first electrode portion 140 and the second electrode portion 150 are located in each region, A solar cell module 11 may be used to form one solar cell module. At this time, the plurality of solar cells 11 may be electrically connected to each other in series or in parallel via interconnectors (or ribbons).

Next, a solar cell module using a solar cell according to an embodiment of the present invention will be described with reference to FIGS. 5 and 6. FIG.

5, the solar cell module 100 according to the present embodiment includes a solar cell array 10, protective films 20a and 20b for protecting the solar cell array 10, (Hereinafter referred to as a 'lower protective film') 20a located on the light receiving surface side of the substrate 10 (hereinafter referred to as a 'upper protective film') 20a, A back sheet 50 disposed at a lower portion of the frame 20b, and a frame 60 for housing these components.

The back sheet 50 protects the solar cell 11 from the external environment by preventing moisture from penetrating from the rear surface of the solar cell module 100. Such a backsheet 50 may have a multi-layer structure such as a layer preventing moisture and oxygen penetration, a layer preventing chemical corrosion, and a layer having insulating properties.

The upper and lower protective films 20a and 20b prevent corrosion of the metal due to moisture penetration and protect the solar cell module 100 from impact. The upper and lower protective films 20a and 20b are integrated with the solar cell array 10 in a lamination process in a state where the upper and lower protective films 20a and 20b are disposed on the upper and lower sides of the solar cell array 10, respectively. The protective films 20a and 20b may be made of ethylene vinyl acetate (EVA), polyvinyl butyral, ethylene vinyl acetate partial oxide, silicon resin, ester resin, olefin resin, or the like.

The transparent member 40 located on the upper protective film 20a has a high transmittance and is made of tempered glass or the like to prevent breakage. At this time, the tempered glass may be a low iron tempered glass having a low iron content. In this transparent member 40, an embossing process can be performed on the inner side in order to enhance the light scattering effect.

The frame 60 is made of a material such as aluminum coated with an insulating material that does not cause corrosion and deformation due to the external environment, and has a structure that allows easy drainage, installation, and construction.

5 and 6, the solar cell array 10 includes a plurality of solar cells 11 arranged in a matrix structure. Each solar cell 11 has a plurality of connection portions 21 and 22, And are electrically connected in series. 5 and 6, the solar cell array 10 has a 4-by-4 matrix structure, but it is not limited thereto and the number of the solar cells 11 arranged in the row and column directions may be adjusted as necessary.

First, the arrangement of the plurality of solar cells 11 arranged in the solar cell array 10 will be described. The two solar cells 11 adjacent in the row direction are arranged in different shapes, and two solar cells 11, (11) are also arranged in different forms.

For example, as shown in Fig. 6, two solar cells 11 adjacent in the row direction and the column direction are arranged to be rotated 180 degrees from each other.

In this example, each connecting portion 21 connects the first bus bar 142 and the second bus bar 152, which are respectively located in the two solar cells 11 in the row direction, to connect two solar cells 11) to be electrically connected in series.

6, in the first row, the second bus bar 152 of the solar cell 11 in the first row is connected to the first bus bar 152 of the solar cell 11 in the second row by the connecting portion 21. Therefore, The connection part 21 is connected to the connection terminal 1511 connected to the second bus bar 152 and the connection terminal 1411 connected to the first bus bar 142. In this case,

The second bus bar 152 of the solar cell 11 located in the second row and not connected to the connection part 21 is connected to the first bus bar of the solar cell 11 located in the third row The connection unit 21 is connected to a connection terminal 1512 connected to the second bus bar 152 and a connection terminal 1412 connected to the first bus bar 142. [

Of course, the second bus bar 152 of the solar cell 11 in the third row, which is not connected to the connection unit 21, is connected to the first bus bar 142 located in the solar cell 11 in the fourth row, ).

In this manner, the first bus bar 142 and the second bus bar 152, which are located in the different solar cells 11 in the adjacent two solar cells 11 located on the same row, are connected by the respective connecting portions 21 And the connection portions 21 for connecting the first bus bar 142 and the second bus bar 152 are connected to each other by two connection terminals 1411 And 1511, or 1412 and 1512, respectively.

At this time, in the same row, each connection portion 21 is alternately located at two connection terminals 1411 and 1511 or two connection terminals 1412 and 1512 located in different solar cells 11. Therefore, in the same row, each connecting portion 21 is alternately located on the upper and lower sides of two adjacent solar cells 11. [

In the two solar cells 11 positioned in different rows and adjacent to each other in the column direction, the first bus bar 142 (or the first bus bar) of the solar cell 11 positioned immediately before or immediately after the solar cell 11 The second bus bar 152 and the second bus bar 152 located in different solar cells 11 which are not connected to the first bus bar 142 and the second bus bar 152, The first bus bars 142 and the second bus bars 142 are connected to each other by the connection portions 22. Each of the connection portions 22 includes first bus bars 142 positioned in two solar cells 11 positioned adjacent to each other in the column direction, 2 bus bar 152 to electrically connect two solar cells 11 adjacent in the column direction.

At this time, each connecting portion 22 has a length longer than each connecting portion 21 since two solar cells 11 located in different rows must be electrically connected in series.

These connection portions 22 are also connected to two connection terminals 1411 and 1512 or 1412 and 1511 respectively located in two solar cells 11. At this time, in order to facilitate connection between the connection terminals 1411, 1511, 1412, or 1512 and the connection portion 22, a separate connection portion 23 (2311, 1511, 1412, or 1512) ). However, the connection portion 23 may be omitted in some cases. At this time, the connection portion 23 is connected to each connection terminal 1411, 1511, 1412, or 1512, and the connection portion 22 can be located between the connection portions 23 located in different solar cells 11 .

In this way, a plurality of solar cells 11 arranged in a matrix structure are electrically connected in series, and in the case of FIG. 6, the solar cells 11 arranged in the first column of the first row, And connected serially in a zigzag manner to the solar cell 11. The first bus bar 142 (or the second bus bar 152) that is not connected to the adjacent solar cell 11 among the solar cells in the first row and the adjacent solar cell 11 And the second bus bar 152 (or the first bus bar 142), which is not connected to the first bus bar 11, with the external device to output electrons and holes collected through the plurality of solar cells 11 connected in series .

In this example, the connecting portions 21-23 are made of a conductive tape, which is a thin metal strip having a string shape and has a conductive material. Examples of the conductive material include nickel (Ni), copper (Cu), silver (Ag), aluminum (Al), tin (Sn), zinc (Zn), indium (In), titanium (Ti) Or a combination thereof, but may be made of any other conductive material.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

Claims (21)

A substrate having a first conductivity type and having a plurality of regions divided in a first direction on a rear surface opposite to an incident surface on which light is incident,
Wherein each of the plurality of regions located on the rear surface comprises:
A plurality of emitter portions extending in the first direction and having a second conductivity type different from the first conductivity type,
A plurality of first electrodes connected to the plurality of emitter portions and extending in the first direction,
A plurality of second electrodes extending in the first direction in a space between the plurality of emitter portions and electrically connected to the substrate and electrically separated from the plurality of first electrodes,
A first bus bar extending in a second direction intersecting the first direction and connecting one end of the plurality of first electrodes,
A second bus bar extending in the second direction and connecting one end of the plurality of second electrodes,
Including the
Wherein a plurality of first bus bars located in each of the plurality of regions are connected to each other and a plurality of second bus bars located in each of the plurality of regions are connected to each other, The electrode and the plurality of second electrodes are located between the first bus bar and the second bus bar located in the corresponding area
Solar cells. delete The method of claim 1,
Wherein the first direction is parallel to a lateral side of the substrate. delete delete The method of claim 1,
And the second direction is parallel to a vertical side of the substrate. The method of claim 6,
Wherein the first bus bar and the second bus bar located in each region are located adjacent to a first vertical side of each of the regions and a second vertical side facing the first vertical side, respectively. delete The method of claim 1,
The extension lengths of the plurality of first electrodes positioned between the first bus bar and the second bus bar are the same and the extension lengths of the plurality of second electrodes positioned between the first bus bar and the second bus bar are the same Solar cells. The method of claim 1,
The lengths of the plurality of first electrodes positioned between the first bus bar and the second bus bar are the same, except for the first electrode and the second electrode located at the edge of the substrate, And the length of the plurality of second electrodes located between the two bus bars is the same. The method of claim 1,
Further comprising a first connection terminal extending in the first direction from each of the plurality of first bus bars and a second connection terminal extending in the first direction from each of the plurality of second bus bars,
Wherein the plurality of first bus bars are connected to each other through the first connection terminal and the plurality of second bus bars are connected to each other through the second connection terminal
Solar cells. [Claim 11]
Wherein a width of the first connection terminal is greater than a width of each of the plurality of first electrodes and a width of the second connection terminal is greater than a width of each of the plurality of second electrodes. The method of any one of claims 1, 3, 6, 7, and 9 to 11,
Further comprising a plurality of electric field portions having the first conductivity type,
And the plurality of second electrodes are electrically connected to the substrate through the plurality of electric field portions. delete delete The method of claim 1,
Wherein the widths of the first electrode and the second electrode are equal to each other. 17. The method of claim 16,
Wherein a width of each of the first electrode and the second electrode is 60 mu m to 3000 mu m. The method of claim 1,
Wherein the widths of the first bus bar and the first bus bar are equal to each other. The method according to claim 1 or 18,
Wherein widths of the first bus bar and the second bus bar are greater than widths of the first electrode and the second electrode. 20. The method of claim 19,
Each of the first bus bar and the second bus bar having a width of 1 mm to 10 mm. A plurality of solar cells connected in series,
A first protective film located on an incident surface of the plurality of solar cells,
A second protective film located on a rear surface opposite to the incident surface of the plurality of solar cells,
A transparent substrate
/ RTI >
Each of the plurality of solar cells
A substrate having a first conductivity type and having a plurality of regions divided in a first direction on the rear surface,
Wherein each of the plurality of regions located on the rear surface comprises:
A plurality of emitter portions extending in the first direction and having a second conductivity type different from the first conductivity type,
A plurality of first electrodes connected to the plurality of emitter portions and extending in the first direction,
A plurality of second electrodes extending in the first direction in a space between the plurality of emitter portions and electrically connected to the substrate and electrically separated from the plurality of first electrodes,
A first bus bar extending in a second direction intersecting the first direction and connecting one end of the plurality of first electrodes,
A second bus bar extending in the second direction and connecting one end of the plurality of second electrodes,
/ RTI >
Wherein a plurality of first bus bars located in each of the plurality of regions are connected to each other and a plurality of second bus bars located in each of the plurality of regions are connected to each other, The electrode and the plurality of second electrodes are located between the first bus bar and the second bus bar located in the corresponding area
Solar module.

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