KR101874016B1 - High efficiency passivated emitter and rear cell having shingled array structure and manufacturing method thereof - Google Patents

Abstract

Various embodiments of the present invention relate to a high efficiency passivated emitter and rear cell (PERC) solar cell having a shingled array structure and a method of manufacturing the same. To solve technical problems, an object of the present invention is to provide a high efficiency PERC solar cell having a shingled array structure which is capable of suppressing an increase of an electrical resistance component which may be increased due to a local rear surface field layer when the shingled array structure is applied to a PERC cell, and a method of manufacturing the same. To this end, the method of manufacturing a high efficiency PERC solar cell having a shingled array structure includes the steps of: preparing a PERC solar cell including a front electrode and a rear electrode; forming an uneven portion on at least one of the front and rear electrodes; singulating the PERC solar cell to prepare a plurality of PERC solar cell units; and bonding a front electrode of one of the PERC solar cell units at one side and a rear electrode of another PERC solar cell unit at an opposite side to each other in a shingled array structure with conductive adhesive interposed therebetween.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high efficiency PERC solar cell having a shingled array structure and a manufacturing method thereof,

Various embodiments of the present invention relate to a high efficiency PERC solar cell having a shunged array structure and a method of manufacturing the same.

With the recent depletion of existing energy resources such as oil and coal, interest in alternative energy to replace them is increasing. Among them, solar cells produce electric energy from solar energy, and they are attracting attention because they have abundant energy resources and there is no problem about environmental pollution.

Typical solar cells have substrates and emitters made of different conductivity type semiconductors, 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 which are charged by the photovoltaic effect, For example, toward the emitter and the substrate, is collected by an electrode electrically connected to the substrate and the emitter, and the electrode is connected to the electric wire to obtain electric power.

The above-described information disclosed in the background of the present invention is only for improving the understanding of the background of the present invention, and thus may include information not constituting the prior art.

SUMMARY OF THE INVENTION The present invention provides a high efficiency PERC solar cell having a shunged array structure and a method of manufacturing the same. Particularly, the problem to be solved according to various embodiments of the present invention is that, when a shingled array structure is applied to a PERC cell, an additional electrical resistance component may increase due to a local back surface field layer. Efficiency PERC solar cell having a shingled array structure capable of suppressing an increase in electrical resistance components, and a method of manufacturing the same. More particularly, the present invention provides a method of surface-treating a rear electrode of a PERC cell to increase a contact area of a conductive material used in a shingled array structure, Efficiency PERC solar cell having a shading array structure capable of improving characteristics such as a fill factor, an open-circuit voltage (Voc), a short-circuit current (Jsc), and the like.

A method of manufacturing a high efficiency PERC solar cell having a shingled array structure according to various embodiments of the present invention includes: preparing a passive emitter and rear cell (PERC) solar cell cell including a front electrode and a rear electrode; Forming an uneven portion on at least one of the front electrode and the rear electrode; Singulating the PERC solar cell to prepare a plurality of PERC solar cell units; And bonding the front electrodes of one PERC solar cell unit and the rear electrodes of the other PERC solar cell unit among the plurality of PERC solar cell units to each other in a shingled array structure manner through a conductive adhesive agent, Wherein the conductive filler-filled thermosetting resin comprises a silver flake as an electrically conductive filler and a polyfunctional epoxy as a thermosetting resin, and the dicarboxylic acid, Aldehyde, and carboxylic acid.

The step of forming the irregularities may be performed using reactive ion etching, sputter etching, reactive ion beam etching, high density plasma etching, or electron beam etching.

The step of forming the concavo-convex part may be performed by forming the concavo-convex part to have a depth and a pitch of 1 to 500 mu m.

The step of bonding the front electrodes and the rear electrodes may have a width of 1 μm to 2 mm.

The step of forming the concave-convex part may be performed by forming an overflow preventing dam around the concave-convex part so that the conductive adhesive does not overflow to the outside of the concave-convex part.

The step of forming the concave-convex part may be performed by forming the concave-convex part in the form of a pyramid, a dome, a triangular pyramid, a cone or a hemisphere.

The step of forming the concave-convex part may be performed by forming the concave-convex part in the form of a plurality of square lines or a plurality of closed curves.

In addition, various embodiments of the present invention can provide a highly efficient PERC solar cell having a shunged array structure manufactured by any one of the above-described methods.

Various embodiments of the present invention provide a high efficiency PERC solar cell having a shunged array structure and a method of manufacturing the same. Particularly, in various embodiments of the present invention, when a shingled array structure is applied to a PERC cell, an additional electrical resistance component may be increased due to a local rear whole layer, and a shingle A highly efficient PERC solar cell having a solar cell array structure and a manufacturing method thereof are provided. Specifically, various embodiments of the present invention surface-process the rear electrode (and / or front electrode) of a PERC cell to increase the contact area of the conductive material used in joining into the shingled array structure, To provide a highly efficient PERC solar cell having a shading array structure capable of improving characteristics such as a fill factor, an open-circuit voltage, and a short-circuit current, and a method of manufacturing the same.

1 is a flowchart illustrating a method of manufacturing a high efficiency PERC solar cell having a shunged array structure according to various embodiments of the present invention.
FIGS. 2A to 2D are sequential sectional views illustrating a method of manufacturing a high efficiency PERC solar cell having a shingled array structure according to various embodiments of the present invention.
3 is a cross-sectional view illustrating a highly efficient PERC solar cell having a shunged array structure according to various embodiments of the present invention.
4 is an enlarged cross-sectional view showing an enlarged junction region in a high efficiency PERC solar cell having a shingled array structure according to various embodiments of the present invention.
FIGS. 5A and 5B are schematic views showing the shape of the irregular portion formed on the front electrode and / or the rear electrode and the application form of the conductive adhesive among the high efficiency PERC solar cells having the shingled array structure according to various embodiments of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The embodiments of the present invention are described in order to more fully explain the present invention to those skilled in the art, and the following embodiments may be modified into various other forms, It is not limited to the embodiment. Rather, these embodiments are provided so that this disclosure will be more faithful and complete, and will fully convey the scope of the invention to those skilled in the art.

In the following drawings, thickness and size of each layer are exaggerated for convenience and clarity of description, and the same reference numerals denote the same elements in the drawings. As used herein, the term "and / or" includes any and all combinations of one or more of the listed items. In the present specification, the term " connected "means not only the case where the A member and the B member are directly connected but also the case where the C member is interposed between the A member and the B member and the A member and the B member are indirectly connected do.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a," "an," and "the" include singular forms unless the context clearly dictates otherwise. Also, " comprise, " and / or "comprising, " when used in this specification, are intended to be interchangeable with the said forms, numbers, steps, operations, elements, elements and / And does not preclude the presence or addition of one or more other features, integers, operations, elements, elements, and / or groups.

Although the terms first, second, etc. are used herein to describe various elements, components, regions, layers and / or portions, these members, components, regions, layers and / It is obvious that no. These terms are only used to distinguish one member, component, region, layer or section from another region, layer or section. Thus, a first member, component, region, layer or section described below may refer to a second member, component, region, layer or section without departing from the teachings of the present invention.

It is to be understood that the terms related to space such as "beneath," "below," "lower," "above, But may be utilized for an easy understanding of other elements or features. Terms related to such a space are for easy understanding of the present invention depending on various process states or use conditions of the present invention, and are not intended to limit the present invention. For example, if an element or feature of the drawing is inverted, the element or feature described as "lower" or "below" will be "upper" or "above." Thus, "lower" is a concept encompassing "upper" or "lower ".

Referring to FIG. 1, there is shown a flowchart of a method of manufacturing a high efficiency PERC solar cell having a shunged array structure according to various embodiments of the present invention.

As shown in FIG. 1, a method of manufacturing a high efficiency PERC solar cell having a shingled array structure according to various embodiments of the present invention includes preparing a PERC solar cell cell S1, forming a concavo-convex portion S2, A singulation step S3, and a bonding step S4.

Referring to FIGS. 2A to 2D, a sequential cross-sectional view of a method for fabricating a high efficiency PERC solar cell having a shunged array structure according to various embodiments of the present invention is shown.

2A, in a PERC solar cell preparation step S1, a PERC solar cell 100 includes a substrate 110 and a substrate 110 on which incident light (hereinafter referred to as a front surface) an antireflection film 130 formed on the emitter 120 and a plurality of passivation layers 130 formed on the rear surface of the substrate 110 opposite to the front surface of the substrate 110. [ A front electrode 150 electrically connected to the emitter 120, a plurality of passivation layers 140 and a back electrode 160 formed on the substrate 110. The back electrode 160 is formed on the substrate 110, And a plurality of rear front layers 170 formed between the rear electrodes 160 and the substrate 110. [

The substrate 110 may be a semiconductor of a first conductivity type, for example, an n-type or p-type conductivity type silicon. The silicon may be monocrystalline silicon, polycrystalline silicon or amorphous silicon. When the substrate 110 is an n-type conductive type, the substrate 110 may include impurities of pentavalent elements such as phosphorous (P), arsenic (As), antimony (Sb) In the case of the p-type conductivity type, it may include impurities of a trivalent element such as boron (B), gallium (Ga), indium (In) and the like.

2A, as an alternative embodiment, the front side of the substrate 110 may be textured to have a texturing surface that is an uneven surface.

Emitter 120 is an impurity of a second conductivity type, e.g., p-type or n-type, opposite to the conductive type of substrate 110 and forms a p-n junction with the semiconductor substrate. Due to the built-in potential difference due to the pn junction, the electron-hole pairs generated by the light incident on the substrate 110 are separated into electrons and holes, electrons move toward the n-type, Moves toward the p-type. Thus, for example, when the substrate 110 is n-type and the emitter 120 is p-type, the separated holes move toward the emitter 120 and the separated electrons move toward the substrate 110, The electrons in the emitter 120 become the majority carriers, and the holes in the emitter 120 become the majority carriers.

The emitter 120 forms a pn junction with the substrate 110. Thus, unlike the present embodiment, when the substrate 110 has a p-type conductivity type, the emitter 120 has an n-type conductivity type . In this case, the separated holes move toward the substrate 110, and the separated electrons move toward the emitter 120.

When the emitter 120 has a p-type conductivity type, the emitter 120 may be formed by doping an impurity of a trivalent element such as boron, gallium, indium, or the like into the substrate 110, 120 may have an n-type conductivity type, the emitter 120 may be formed by doping an impurity of a pentavalent element such as phosphorus, arsenic, antimony, and the like on the substrate 110.

The antireflection film 130 may be formed by depositing a silicon nitride film (SiNx) or a silicon oxide film (SiOx) on the emitter 120. The antireflection film 130 reduces the reflectance of light incident on the solar cell and increases the selectivity of a specific wavelength region, thereby enhancing the efficiency of the solar cell. The antireflection film 130 may be omitted if necessary.

A plurality of protective films 140 are formed on the rear surface of the substrate 110 and serve to reduce the recombination rate of the charges near the rear surface of the substrate 110. Since the light passing through the substrate 110 is reflected by the plurality of protective films 140 and re-enters the substrate 110 side, the re-incident rate of light passing through the substrate 110 by the plurality of protective films 140 .

The plurality of protective films 140 may be formed of, for example, a silicon nitride film or a silicon oxide film. In addition, the plurality of protective films 140 may be formed of various inorganic dielectrics (for example, silicide-based materials) having low resistivity values.

A plurality of front electrodes 150 are formed on the emitter 120 and are electrically connected to the emitter 120 and extend in a predetermined direction away from each other. The plurality of front electrodes 150 collects charges, for example, holes / electrons, which have migrated toward the emitter 120, and outputs the collected charges to an external device.

The plurality of front electrodes 150 may be formed of a material selected from the group consisting of Ni, Cu, Ag, Al, Sn, Zn, (In), titanium (Ti), gold (Au), and combinations thereof.

The rear electrode 160 is also made of a conductive material, and is substantially integrally formed on the rear surface of the substrate 110 and a plurality of the protective films 140. A plurality of exposed portions are exposed between the protective film 140 and the protective film 140 to expose the rear surface of the substrate 110 as a lower layer so that a part of the rear electrode 160 is electrically connected to the substrate 110 through the exposed portion. . The rear electrode 160 collects charges, for example, electrons / holes, moving from the substrate 110 side and outputs the collected charges to an external device.

The back electrode 160 may be formed of, for example, but not limited to, nickel, copper, silver, aluminum, tin, zinc, indium, , Titanium (Ti), gold (Au), and combinations thereof.

The rear front layer 170 may be formed between the rear electrode 160 and the substrate 110. The plurality of rear whole layers 170 are regions in which impurities of the same conductivity type as the substrate 110 are doped at a higher concentration than the substrate 110, for example, n + / p + regions. A potential barrier is formed due to a difference in impurity concentration between the substrate 110 and the rear front layer 170 so that hole / electron movement toward the rear surface of the substrate 110 is impeded, And the phenomenon that the holes recombine and disappear is prevented.

The PERC solar cell 100 according to this embodiment having such a structure has a plurality of protective films 140 formed on the rear surface of the substrate 110 to prevent electric charges Reduction of recombination and its operation is as follows.

When light is irradiated to the solar cell 100 and is incident on the semiconductor substrate 110 through the antireflection film 130 and the emitter 120, electron-hole pairs are generated in the semiconductor substrate 110 due to light energy. At this time, the reflection loss of the light incident on the substrate 110 is reduced by the anti-reflection film 130, and the amount of light incident on the substrate 110 is increased.

The electrons and holes of these electron-hole pairs are formed by the pn junction of the substrate 110 and the emitter 120, for example, with the emitter 120 having the p-type conductivity type and the emitter 120 having the n- To the substrate 110 side.

As described above, the holes moved toward the emitter 120 are collected by the front electrode 150, and the electrons moved toward the substrate 110 are collected by the adjacent rear electrode 160. When the front electrode 150 and the rear electrode 160 are connected to each other by a conductive line, a current flows and can be used as external power.

Since a plurality of protective films 140 having a low resistivity and excellent contact properties with silicon (Si) are further formed between the substrate 110 and the rear electrode 160, the recombination of charges due to unstable bonding on the surface of the substrate 110 The efficiency of the solar cell is improved.

2B, irregularities 151 and 161 may be formed on the front electrode 150 and / or the rear electrode 160 in the step S2 of forming the concave and convex portions. The concave-convex portions 151 and 161 may be formed by, for example, reactive ion etching, sputter etching, reactive ion beam etching, high density plasma etching, sandblasting etching, or electron beam etching, although not limited thereto.

The concave and convex portions 151 and 161 may be formed by an electron beam etching method of 2.5 keV for 60 seconds, for example. The concave and convex portions 151 and 161 may be formed by various wet etching methods as another example. Further, the concave-convex portions 151 and 161 may be formed in a pattern shape having a precise depth and pitch by a normal photo-etching process.

In addition, it is preferable that the depth (or the height / thickness) and the pitch of the concave-convex portions 151 and 161 are formed to be approximately 1 μm to approximately 500 μm.

If the depth and pitch of the concave and convex portions 151 and 161 are less than about 1 탆, the conductive adhesive 190 may flow to an undesired region during the dispensing process of the conductive adhesive 190 to be described below, The outer side of the bonding region 180 to be formed may be contaminated with the conductive adhesive 190. This may lower the efficiency of solar cells by lowering the incident rate of sunlight.

 If the depth and pitch of the concave and convex portions 151 and 161 are larger than about 500 占 퐉, the conductive adhesive 190 during the dispensing process of the conductive adhesive 190 may not sufficiently cover the concave and convex portions 151 and 161, The region 180 may not be formed. That is, since the height of the uppermost portion of the concave and convex portions 151 and 161 is too high to cover the portion with the conductive adhesive 190, bonding between them may not be performed smoothly.

The sectional shape of the concave and convex portions 151 and 161 may include, for example, but not limited to, a tetragonal pyramid, an inverted pyramid, a dome, a triangular pyramid, a cone or a hemispherical shape. The joining area of the joining area 180 to be formed is increased by the concave-convex parts 151 and 161 of various stiffnesses, and thus the mechanical / electrical joining force in the joining area 180 can be improved.

The widths of the concave portions 151 and 161 formed on the front electrode 150 and / or the rear electrode 160 (in other words, the width of the overlap region of the front electrode 150 and the rear electrode 160, (The width of the recess 180) is preferably approximately 1 to 2 mm.

The mechanical / electrical bonding force between one side of the PERC solar cell unit 101 and the other side of the PERC solar cell unit 101 is smaller than the width of the bonding region 180 when the width of the concave and convex portions 151 and 161, They are weak and easily separated from each other.

Further, if the width of the concave-convex portions 151 and 161, the overlap region, or the width of the bonding region 180 is larger than about 2 mm, the light receiving area with respect to sunlight can be reduced. This leads to a reduction in the overall efficiency of the solar cell.

As shown in FIG. 2C, in the singulation step S3, the PERC solar cell 100 is sowed or singulated, and a single PERC solar cell unit 101 is provided. The PERC solar cell 100 may be separated into a plurality of PERC solar cell units 101 by, for example, but not limited to, a laser beam, a diamond blade, or a chemical etching method. One PERC solar cell unit 101 includes a front electrode 150 having a concave portion 151 on one side and a rear electrode 160 having a concave portion 161 on the other side ).

The front electrode 150 of one of the plurality of PERC solar cell units 101 and the front electrode 150 of the other of the plurality of PERC solar cell units 101 are connected to each other in the bonding step S4, A conductive adhesive agent 190 is interposed between the rear electrodes 160 of the backlight unit 160 and is bonded to each other in a shingled array structure manner.

For example, the conductive adhesive 190 is pressed between the front electrode 150 of the one PERC solar cell unit 101 and the rear electrode 160 of the other PERC solar cell unit 101 , And a temperature of about 100 DEG C to 250 DEG C is provided, so that they can be mechanically / electrically connected to each other. Here, the region formed by the conductive adhesive 190 may be defined as the junction region 180.

The conductive adhesive 190 may be dispensed only on the concave and convex portions 151 of the front electrode 150 of the one PERC solar cell unit 101 or on the rear electrode 160 of the other PERC solar cell unit 101. [ After being dispensed only to the concave / convex portion 161, the bonding process can be performed. The conductive adhesive 190 is applied to the uneven portion 151 of the front electrode 150 of the one PERC solar cell unit 101 and the uneven portion 161 of the rear electrode 160 of the other PERC solar cell unit 101 ), The bonding process can be performed.

Such a conductive adhesive 190 may include, for example, but not limited to, a conductive filler-filled thermosetting resin.

The conductive filler plays a role of bringing the particles into contact with each other to conduct electricity. Examples of the material of the conductive particles include silver (Ag), gold (Au), nickel (Ni) ), Carbon (C), and the like can be used in various sizes and shapes. Of these, silver is the most desirable because it has the characteristics of ① high conductivity ② simple processing ③ maximum contact effect in flake form ④ less deterioration even when it becomes an oxide (the oxide of other metal becomes an insulator) to be.

The particle shape of the conductive filler is preferably a flake-like particle for surface contact with many points. Such a conductive filler may have a particle size of, for example, but is not limited to, approximately 1 m to 3 m, and may have a weight ratio of approximately 10 wt% to 90 wt% of the conductive adhesive 190.

Further, the thermosetting resin may include, for example, epoxy, cyanate ester, silicone, and polyurethane, though it is not limited thereto. Of course, thermoplastic resins such as polyimide and epoxy phenol may be used in addition to the thermosetting resin.

The thermoplastic resin has advantages of easy repairing or reworking, but it is easily deteriorated at high temperature and may contain a solvent such as polyimide (residual solvent becomes a problem of reliability due to evaporation due to evaporation during heating).

In various embodiments of the present invention, thermosetting epoxy resins having the advantages of adhesion, chemical resistance, corrosion resistance, low cost, etc. are most preferred.

Meanwhile, in order to further improve the electrical conductivity of the conductive adhesive 190, the following process may be further performed.

The shrinkage of the polymer matrix is also increased. In general, the conductive adhesive 190 is further improved in electric conductivity after curing as compared with before curing. Therefore, in the case of a conductive adhesive based on epoxy, a polyfunctional epoxy may be added to increase the electrical conductivity while increasing the shrinkage upon curing.

The replacement of the lubricant film on the flake surface. The conductive adhesive 190 containing the flake has a film of organic lubricating oil on the flake surface that helps disperse into the matrix and has rheological properties with the adhesive. Since this film has an insulating property, the electric conductivity can be further improved by removing a part or all of the film (for example, adding a short chain dicarboxylic acid) during the curing operation of the conductive adhesive.

When a silver flake contained in the conductive adhesive 190 is oxidized, the silver oxide remains conductive (other metal oxides have insulating properties), but the conductivity is lower than that of the metal itself. Therefore, when the conductive adhesive agent 190 is compounded, aldehydes are added to reduce silver oxide to silver, and a carboxylic acid is generated, so that the electrical conductivity can be doubled

(TLP: Transient Liquid Phase) filler - When a metal mixture forming TLP is used as a filler, a liquid phase is formed at a low temperature during the curing operation, and a low melting point metal (for example, Sn-58Bi: A network of Sn-50.9In: melting point of 117 占 폚) and a refractory metal (for example, Sn-0.7Cu: melting point of 221 占 폚, Sn-3.5Ag: melting point of 221 占 폚) can be formed and electric conductivity can be further improved.

Low temperature sintering of silver nanopiller - When nanopillar is used, nano-sized particles have higher contact resistance than micron-sized particles, resulting in lower electrical conductivity. However, if the silver nanoparticles are sintered rapidly below 100 ° C, The electrical conductivity can be improved.

Thus, according to various embodiments of the present invention, even when a shingled array structure is applied to a PERC solar cell, an increase in additional resistance components can be suppressed. That is, the surface area of the front electrode 150 and / or the rear electrode 160 of the PERC solar cell 100 may be surface-treated to increase the contact area of the conductive adhesive 190 used in the shingled array structure, As a result, the resistance component can be reduced to improve the characteristics of the fill factor, open-circuit voltage and short-circuit current. Furthermore, according to various embodiments of the present invention, various treatments (for example, increasing the shrinkage of the polymer matrix, replacing the lubricant film on the silver flake surface, adding a reducing agent, using a low temperature transition liquid filler, low temperature sintering, etc.) It is possible to further reduce the electrical resistance of the conductive adhesive.

Referring to FIG. 3, a cross-sectional view of a high efficiency PERC solar cell 102 having a shingled array structure according to various embodiments of the present invention is shown.

3, the width of the concave-convex portions 151 and 161 or the width of the bonding region 180 formed in the front electrode 150 and / or the rear electrode 160 is substantially the same as that of the entire PERC solar cell 102 And the PERC solar cell units 101 bonded to each other have a substantially shingled array structure. That is, when the PERC solar cell 101 is placed on a flat surface, each of the PERC solar cell 101 has a shape substantially inclined with respect to the ground.

Referring to FIG. 4, there is shown an enlarged cross-sectional view of a junction region 180 in a high efficiency PERC solar cell having a shingled array structure according to various embodiments of the present invention.

The overflow preventing dams 152 and 162 may be further formed so that the conductive adhesive 190 does not overflow to the outside of the concave and convex portions 151 and 161 around the concave and convex portions 151 and 161 as shown in FIG. The dams 152 and 162 may protrude from the concave and convex portions 151 and 161 at a predetermined height. That is, a dam 152 protruding from the front electrode 150 around the concave / convex portion 151 and / or a dam 162 protruding from the rear electrode 160 around the concave / convex portion 161 .

The overflow preventing dams 152 and 162 are formed in the shape of a substantially square line or a closed curve when seen from the plane so that the conductive adhesive 190 dispensed on the inside thereof overflows to the outside of the dams 152 and 162 .

In addition, such dams 152 and 162 may be formed of a conductor or an insulator.

When dams 152 and 162 are formed with conductors, for example, but not limited to, dams 152 and 162 may be formed of eutectic solder (Sn37Pb), high lead solder (Sn95Pb), or leadless solder and the back electrode 160 formed on the front electrode 150 may be formed of lead-free solder such as SnCu, SnAg, SnAgCu, SnAgBi, SnAgBiIn, SnAgZn, AnZn, SnBi, SnIn, The dams 152 can be electrically connected to each other through reflow. Therefore, these dams 152 and 162 can further improve the electrical conductivity between the PERC solar cell unit 101 on one side and the PERC solar cell unit 101 on the other side together with the conductive adhesive 190.

5A and 5B, a concave / convex portion (not shown) formed on the front electrode 150 and / or the rear electrode 160 among the high efficiency PERC solar cells 102 having a shingled array structure according to various embodiments of the present invention 251, 261) and a coating form of the conductive adhesive 190 are shown.

5A, the concave and convex portions 251 indicated by the dotted lines on the left side are formed on the front electrode 150, and the concave and convex portions 261 shown on the right side in FIG. 5A are formed on the rear electrode 160. Fig. 5B shows the concavoconvex portion 261 reduced to a square shape for convenience of understanding.

5B, the concave and convex portions 261 may be formed in a plurality of square lines or a plurality of closed curve shapes, and the conductive adhesive 190 may be applied to the inside of the concave and convex portions 261. Here, the application region of the conductive adhesive 190 should be formed to be smaller than the outermost size of the concave-convex portion 261. For example, the application region of the conductive adhesive 190 may be formed on the inside of three to five concavities and convexities from the outermost portion of the concave-convex portion 261. Therefore, when the irregularities 251 formed on the front electrode 150 on one side and the irregularities 261 formed on the rear electrode 160 on the other side are pressed and cured with each other via the conductive adhesive 190 in the bonding step The overflow phenomenon of the conductive adhesive 190 is prevented due to the characteristics of the concave-convex portions 251 and 261 in the form of a plurality of square lines or a plurality of closed curved lines. That is, a plurality of square lines or a plurality of closed curve-shaped irregularities formed on the outside of the dispensing area of the conductive adhesive 190 perform the dam function instead.

The present invention is not limited to the above-described embodiment, but may be applied to other types of solar cells, such as the following patent claims It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims.

100; PERC solar cell
101; PERC solar cell unit
102; PERC solar cell
110; Board
120; Emitter
130; Antireflection film
140; Shield
150; Front electrode
151; Uneven portion
152; dam
160; Rear electrode
161; Uneven portion
162; dam
170; Rear front layer
180; Junction region
190; Conductive adhesive

Claims (9)

Preparing a passive emitter and rear cell (PERC) solar cell cell including a front electrode and a rear electrode;
Forming an uneven portion on at least one of the front electrode and the rear electrode;
Singulating the PERC solar cell to prepare a plurality of PERC solar cell units; And
A step of bonding a front electrode of one PERC solar cell unit and a rear electrode of the other PERC solar cell unit among the plurality of PERC solar cell units in a shingled array structure manner via a conductive adhesive;
Wherein the conductive filler-filled thermosetting resin comprises a silver flake as a conductive filler and a polyfunctional epoxy as a thermosetting resin, and the dicarboxylic acid , An aldehyde, and a carboxylic acid. The method according to claim 1,
Wherein the step of forming the concave-convex portion is performed using a reactive ion etching, a sputter etching, a reactive ion beam etching, a high density plasma etching, or an electron beam etching method. The method according to claim 1,
Wherein the step of forming the concavo-convex portion is performed by forming the depth and pitch of the concavo-convex portion to be 1 占 퐉 to 500 占 퐉. delete The method according to claim 1,
Wherein the step of bonding the front electrodes and the rear electrodes comprises the step of forming a region of overlap between the front electrodes and the rear electrodes of 1 占 퐉 to 2 mm. The method according to claim 1,
Wherein the step of forming the concave-convex portion is performed by forming an overflow preventing dam around the convexo-concave portion so that the conductive adhesive does not overflow to the outside of the convexo-concave portion. The method according to claim 1,
Wherein the step of forming the concave-convex portion is performed by forming the concave-convex portion in a pyramid, a dome, a triangular pyramid, a cone, or a hemispherical shape. The method according to claim 1,
Wherein the step of forming the concavo-convex portion is performed by forming the concavo-convex portion in the form of a plurality of square lines or a plurality of closed curved lines. A high efficiency PERC solar cell having a shingled array structure manufactured by the method according to any one of claims 1 to 3 and 5 to 8.

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