KR101883758B1 - Compound semiconductor solar cell module - Google Patents

Abstract

According to an embodiment of the present invention, a compound photovoltaic cell module capable of preventing deterioration of a junction portion between photovoltaic cells includes a plurality of compound photovoltaic cells partially overlapping each other in an overlapping region. The plurality of compound photovoltaic cells include a compound semiconductor layer, first and second electrodes formed on the front surface and the rear surface of the compound semiconductor layer, and a bussing substrate exposing a portion of the second electrode and formed on the entire surface of the rear surface of the second electrode. The bussing substrate includes an insulating substrate having a metal contact unit in electrical contact with the second electrode and an insulating film formed on both surfaces of an insulating material to expose the metal contact unit. The plurality of compound photovoltaic cells neighboring each other are electrically and physically connected by the metal contact unit disposed in the overlapping region.

Description

COMPOUND SEMICONDUCTOR SOLAR CELL MODULE [0001]

The present invention relates to a superposed compound solar cell module.

The compound semiconductor is not a single element such as silicon or germanium, but two or more elements are combined to operate as a semiconductor. Various kinds of compound semiconductors are currently being developed and used in various fields.

Among them, the compound solar cell is a III-V compound semiconductor such as gallium arsenide (GaAs), indium phosphorus (InP), gallium aluminum arsenide (GaAlAs), gallium indium arsenide (GaInAs), cadmium sulfur (CdS) A Group II-VI compound semiconductor such as tellurium (CdTe) or zinc sulfide (ZnS), or an I-III-VI compound semiconductor represented by copper indium selenium (CuInSe2).

Such a compound solar cell has a very thin thickness, and a supporting substrate is attached to the rear electrode formed on the entire surface of the rear surface of the solar cell for easy handling.

However, when the compound solar cells provided with the supporting substrate are connected to each other, the supporting substrate hides the rear electrode, which makes it difficult to electrically connect the compound solar cells.

SUMMARY OF THE INVENTION The present invention has been made in view of the above technical background, and is aimed at easily stacking compound semiconductor solar cells.

The present invention aims at solving various other technical problems, and the problems not described herein can be easily understood by the description of the present invention or by those skilled in the art.

The compound solar cell module according to an embodiment of the present invention includes a plurality of compound solar cells partially overlapping each other in the overlap region, and the plurality of compound solar cells include a compound semiconductor layer, a front surface and a rear surface of the compound semiconductor layer And a bushing substrate which exposes a first electrode, a second electrode and a part of the second electrode, and which is formed on the entire rear surface of the second electrode, wherein the bushing substrate has a metal contact portion in electrical contact with the second electrode And an insulating film formed on both surfaces of the insulating base material to expose the metal contact portion, wherein the plurality of compound solar cells neighboring each other are electrically and physically connected by the metal contact portion disposed in the overlapping region.

The metal contact portion may include a through hole exposing the second electrode, and a conductive metal formed in the through hole.

The conductive metal may further include lands connected to the conductive metal, the conductive metal being formed on the front surface and the rear surface of the insulating substrate facing the through hole, respectively.

The conductive metal and the land may be formed as a single body.

The conductive metal and the land may be formed of copper or the same conductive material as the second electrode.

The metal contact portions may be formed discontinuously in the overlap region.

The insulating layer may include a conductive portion electrically and physically connected to the metal contact portion.

The conductive portion may include a via hole exposing the metal contact portion at the front and rear surfaces, respectively, and a conductor electrically and physically bonded to the metal contact portion to fill the via hole.

The conductor may be formed of at least one of solder or conductive adhesive.

The supporting substrate may further include a supporting substrate positioned between the second electrode and the bushing substrate and having a bonding portion for electrically and physically connecting the second electrode and the metal contact portion.

A compound solar cell module according to another embodiment of the present invention includes:

A plurality of compound solar cells partially overlapping each other in the overlap region,

Wherein the plurality of compound solar cells comprises a conductive substrate and a metal contact portion electrically connected to the conductive substrate, the insulating substrate being formed on both surfaces of the conductive substrate, and the metal contact portion disposed in the overlap region The plurality of compound solar cells are electrically and physically connected.

The conductive substrate may be a metal foil.

The metal contact portion includes a via hole exposing a part of the conductive base material on the front and rear surfaces of the conductive base material, and a conductor electrically and electrically connected to the conductive base material filling the via hole.

The conductor may be formed of at least one of solder or conductive adhesive.

The metal contact portions may be formed discontinuously in the overlap region.

And a supporting substrate which is positioned between the second electrode and the bushing substrate and on which a bonding portion for electrically and physically connecting the second electrode and the metal contact portion is formed.

According to the embodiment of the present invention, since the metal contact portion to be bonded to the electrode is formed inside the bushing substrate, it is possible to prevent deterioration of the junction portion between the solar cells even when the metal contact portion is used for a long time in a place where a change in external environment such as temperature and humidity is severe. can do.

1 is a plan view of a compound solar cell module according to an embodiment of the present invention.
2 is a schematic sectional view taken along the line A-A 'of FIG.
3 is a view for explaining a specific configuration of a compound solar cell.
4 is a view showing an entire structure of a compound solar cell according to an embodiment of the present invention.
5 is a cross-sectional view taken along line B-B 'of FIG.
6 is a view showing a state in which a conductive metal is formed in a horseshoe shape.
7 is a rear view of the compound solar cell.
8 is a cross-sectional view of a compound solar cell according to another embodiment of the present invention.
Fig. 9 is a view showing a cross-sectional view of a compound solar cell including a supporting substrate.

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 explain the present invention in the drawings, parts not related to the description may be simplified or omitted. In addition, the various embodiments shown in the drawings are provided by way of example and for simplicity of explanation, the components are simplified and shown in a different manner from the actual ones.

In the following detailed description, the same reference numerals are assigned to the same components that do not differ according to the embodiments, and description thereof will not be repeated.

FIG. 1 is a plan view of a compound solar cell module according to an embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view taken along line A-A 'of FIG.

Referring to these drawings, a compound solar cell module according to an embodiment of the present invention may be formed by stacking a plurality of compound solar cells 10 in an overlap region 11a.

On the rear surface of the compound solar cell 10, a bushing substrate 17 having a metal contact portion 30 forming an electrical contact is formed over the entire surface. The bushing substrate 17 may be added to maintain the shape of the compound solar cell 10 formed to have a small thickness and the metal contact portion 30 is electrically and electrically connected to the second electrode formed on the back surface of the solar cell .

As shown in the drawing, when two solar cells neighboring in a first direction (x-axis direction in the drawing) are referred to as a first solar cell C1 and a second solar cell C2, respectively, And a part of the rear surface of the second solar cell C2 may be overlaid and electrically connected to a part of the front surface of the second solar cell C2.

Here, in the overlap region 11a, the metal contact portions 30 located on the rear surface of the first solar cell C1 are located above the second solar cell C2, and the two are more firmly bonded. The metal contact portion 30 is located between the first solar cell C1 and the second solar cell C2 in the overlap region 11a to increase the contact area between the first and second solar cells C1 and C2 to reduce the contact resistance, C1 and the second solar cell C2 can be attached easily.

The metal contact portion 30 may be partially formed in the second direction (y-axis direction in the drawing) along the overlap region 11a.

The solar cell used in one embodiment of the present invention is a solar cell in which the semiconductor layer is made of III-V (GaAs) such as gallium arsenide (GaAs), indium phosphide (InP), gallium aluminum arsenide (GaAlAs), gallium indium arsenide II-VI compound semiconductors such as cadmium sulphide (CdS), cadmium tellurium (CdTe), and zinc sulfide (ZnS), I-III-VI compound semiconductors represented by copper indium selenide Is used as a compound semiconductor layer.

Hereinafter, the interlayer structure of the compound solar cell will be described in more detail with reference to FIG.

3, the compound solar cell 10 includes a light absorption layer PV, a window layer 111 located on the front surface of the light absorption layer PV, A front contact layer 113 positioned between the window layer 111 and the front electrode 13; an antireflection film 114 positioned on the window layer 111; (Hereinafter referred to as a rear electrode) 15 positioned on the rear surface of the rear contact layer 115 and the rear surface of the rear contact layer 115, which are positioned on the rear surface of the substrate PV.

At least one of the antireflection film 114, the window layer 111, the front contact layer 113, and the rear contact layer 115 may be omitted. However, as shown in FIG. 7, For example.

The light absorbing layer (PV) may be formed including a III-VI group semiconductor compound. For example, GaInP compound containing gallium (Ga), indium (In) and phosphorus (P), or GaAs compound containing gallium (Ga) and arsenic (As).

Hereinafter, a description will be given by exemplifying that the light absorbing layer (PV) includes a GaAs compound.

The light absorbing layer PV is formed of a p-type semiconductor layer (PV-p) doped with a first conductive type impurity, for example, a p-type impurity and an n-type semiconductor doped with an impurity of the second conductive type, Layer (PV-n).

Although not shown, the light absorbing layer PV may further include a rear front layer located on the rear surface of the p-type semiconductor layer PV-p.

The p-type semiconductor layer (PV-p) is formed by doping the above-described compound with the first conductivity type, that is, the p-type impurity, and the n-type semiconductor layer (PV-n) an n-type impurity may be doped.

Here, the p-type impurity may be selected from carbon, magnesium, zinc or a combination thereof, and the n-type impurity may be selected from silicon, selenium, tellurium or a combination thereof.

The n-type semiconductor layer PV-n may be located in a region adjacent to the front electrode 13 and the p-type semiconductor layer PV-p may be disposed on the rear electrode 15 In the region adjacent to the center of gravity.

That is, the interval between the n-type semiconductor layer PV-n and the front electrode 13 is smaller than the interval between the p-type semiconductor layer PV-p and the front electrode, The interval between the back electrodes 15 is larger than the interval between the p-type semiconductor layer (PV-p) and the back electrode.

As a result, a pn junction in which the p-type semiconductor layer (PV-p) and the n-type semiconductor layer (PV-n) are joined is formed in the light absorbing layer PV, The generated electron-hole pairs are separated into electrons and holes by the internal potential difference formed by the pn junction of the light absorbing layer (PV), so that the electrons move toward the n-type and the holes move toward the p-type.

Therefore, the holes generated in the light absorbing layer PV move to the rear electrode 15 through the rear contact layer 115 and the electrons generated in the light absorbing layer PV pass through the window layer 111 and the front contact layer 113 To the front electrode (13).

Alternatively, the p-type semiconductor layer PV-p is located in the region adjacent to the front electrode 13 and the n-type semiconductor layer PV-n is located in the rear electrode 15 directly below the p-type semiconductor layer PV- Holes generated in the light absorbing layer PV move to the front electrode 13 through the front contact layer 113 and electrons generated in the light absorbing layer PV are incident on the rear contact layer 115 To the rear electrode 15 through the contact hole.

The back front layer may include an upper layer directly contacting with the upper layer, that is, an n-type semiconductor layer (PV-n) or a p-type semiconductor layer Layer PV-p, and may be formed of the same material as the window layer 111 or a different material.

For example, the back-front layer may be formed of AlGaInP.

In order to effectively block the transfer of charges (holes or electrons) to be transferred to the front electrode toward the rear electrode, the upper rear layer is a layer directly contacting the upper electrode, that is, the n-type semiconductor layer (PV-n) and is formed entirely on the rear surface of the p-type semiconductor layer PV-p.

That is, when the front layer is formed on the rear surface of the p-type semiconductor layer PV-p, the front layer acts to block electrons from moving toward the rear electrode and effectively blocks electrons from moving toward the rear electrode , The entire back surface layer is located on the entire rear surface of the p-type semiconductor layer (PV-p).

The light absorbing layer (PV) having such a structure may be manufactured from a mother substrate by a metal organic chemical vapor deposition (MOCVD) method, a molecular beam epitaxy (MBE) method, or any other suitable method for forming an epitaxial layer .

The p-type semiconductor layer (PV-p) and the n-type semiconductor layer (PV-n) can be made of the same material having the same band gap (homogeneous junction) (Heterogeneous junction).

The window layer 111 may be formed between the light absorption layer PV and the front electrode 13 and may be formed by doping a Group III-VI semiconductor compound, for example, AlInP with a second conductivity type, that is, an n-type impurity .

Here, aluminum (Al) is included in the window layer 111 to form the energy band gap of the window layer 111 higher than the energy band gap of the light absorption layer.

However, when the p-type semiconductor layer PV-p is located on the n-type semiconductor layer PV-n and the window layer 111 is located on the p-type semiconductor layer PV-p, 1 conductive type, that is, a p-type impurity.

However, the window layer 111 may not contain n-type or p-type impurities.

The window layer 111 serves to passivate the front surface of the light absorbing layer PV. Therefore, when the carrier (electrons or holes) moves to the surface of the light absorbing layer PV, the window layer 111 can prevent the carriers from recombining on the surface of the light absorbing layer PV.

Since the window layer 111 is disposed on the front surface of the light absorbing layer PV, that is, on the light incident surface, the window layer 111 is formed to have a thickness smaller than the energy band gap of the light absorbing layer PV in order to substantially absorb light incident on the light absorbing layer PV. It can have a high energy bandgap.

The antireflection film 114 may be located in a region other than a region where the front electrode 13 and / or the front contact layer 113 are located in the front surface of the window layer 111.

Alternatively, the antireflection film 114 may be disposed on the front contact layer 113 and the front electrode 13, as well as the exposed window layer 111. [

In this case, although not shown, the compound semiconductor solar cell may further include a bus bar electrode that physically connects the plurality of front electrodes 13, and the bus bar electrode is not covered by the anti-reflection film 114, .

The antireflection film 114 having such a configuration may include magnesium fluoride, zinc sulfide, titanium oxide, silicon oxide, derivatives thereof, or a combination thereof.

The front electrode 13 may be formed to extend in a second direction (y-axis direction in the drawing), and a plurality of front electrodes 13 may be spaced apart at regular intervals along a first direction (x-axis direction in the figure) perpendicular to the second direction .

The front electrode 13 having such a structure may be formed of an electrically conductive material and may be formed of a metal such as Au, Pt, Ti, W, Si, Ni, And at least one material selected from magnesium (Mg), palladium (Pd), copper (Cu), and germanium (Ge).

The front contact layer 113 located between the window layer 111 and the front electrode 13 is formed by doping a Group III-VI semiconductor compound with a second impurity at a doping concentration higher than the impurity doping concentration of the window layer 111 can do.

The front contact layer 113 forms an ohmic contact between the window layer 111 and the front electrode 13. That is, when the front electrode 13 directly contacts the window layer 111, the ohmic contact between the front electrode 13 and the light absorbing layer PV is not well formed due to the low doping concentration of the impurity in the window layer 111 Do not. Therefore, the carrier moved to the window layer 111 can not easily move to the front electrode 13 and can be destroyed.

However, when the front contact layer 113 is formed between the front electrode 13 and the window layer 111, the carrier is smoothly moved by the front contact layer 113 forming the ohmic contact with the front electrode 13 The short circuit current density (Jsc) of the compound semiconductor solar cell increases. As a result, the efficiency of the solar cell can be further improved.

In order to form an ohmic contact with the front electrode 13, the front contact layer 113 may be formed of GaAs or AlGaAs having good electrical conductivity. The doping concentration of the second impurity doped in the front contact layer 113 may be, May be higher than the doping concentration of the second dopant doped to the layer (111).

The front contact layer 113 is formed in the same shape as the front electrode 13.

When the rear surface of the p-type semiconductor layer PV-p of the light absorbing layer PV and the light absorbing layer PV are provided on the rear surface front layer, the rear surface contact layer 115 located on the rear surface of the rear front layer, PV) and can be formed by doping the impurity of the first conductivity type in the III-VI group semiconductor compound at a higher doping concentration than the p-type semiconductor layer (PV-p).

The rear contact layer 115 may be formed of GaAs or AlGaAs having good electrical conductivity to form an ohmic contact with the rear electrode 115, thereby further improving the short circuit current density Jsc of the compound semiconductor solar cell . As a result, the efficiency of the solar cell can be further improved.

The thickness of the front contact layer 113 and the thickness of the rear contact layer 115 may be respectively 1110 nm to 1130 nm. For example, the front contact layer 113 may have a thickness of 1110 nm, 115 may be formed with a thickness of 1130 nm.

The rear electrode 15 positioned on the rear surface of the rear contact layer 115 may be formed as a sheet-like conductor located entirely on the rear surface of the rear contact layer 115, unlike the front electrode 13 . That is, the rear electrode 15 may be referred to as a sheet electrode located on the entire rear surface of the rear contact layer 115.

The rear electrode 15 is made of gold (Au), platinum (Pt), titanium (Ti), tungsten (W), silicon (Si), nickel (Ni), magnesium (Mg) , Palladium (Pd), copper (Cu), and germanium (Ge).

Since such compound solar cells are made of very thin films, they can be further constructed with a bushing substrate attached to the back electrode for shape maintenance and support.

4 and 5, the structure of a compound solar cell including a bushing substrate according to an embodiment of the present invention will be described.

FIG. 4 shows an overall view of a compound solar cell according to an embodiment of the present invention, and FIG. 5 is a cross-sectional view taken along line B-B 'of FIG.

4 and 5, the compound solar cell 10 includes a semiconductor layer 11 formed of a compound semiconductor, a front electrode 13 and a rear electrode 15 formed on the front and rear surfaces of the semiconductor layer 11, .

The front electrode 13 is positioned in the front direction in which the light is incident, and may include narrow finger electrodes 13a so as not to block the incident light. One end of the finger electrodes 13a is connected to each other by a bus electrode 11b formed along the edge of the compound semiconductor layer 11. It is preferable that the line width of the bus electrode 11b is thicker than the line width of the finger electrodes 13a. The front electrode 13 includes a finger electrode 13a formed in the first direction and a bus electrode 13b formed in the second direction, so that the front electrode 13 may have a comb-like shape as a whole.

The rear electrode 15 may be formed as a common electrode on the entire rear surface of the compound semiconductor layer 11, as shown in FIG.

The front electrode 13 and the second electrode 15 may be formed of a metal such as Au, Pt, Ti, W, Si, Ni, And at least one material selected from palladium (Pd), copper (Cu), and germanium (Ge).

Meanwhile, the thickness of the compound semiconductor layer 11 may be about 3 to 5 (um), and the thickness of the electrodes 13 and 15 may be about 5 (um) to 10 (um). Therefore, the combined thickness of the compound semiconductor layer 11 and the electrodes 13 and 15 has a very thin thickness of about 20 (um). Therefore, a bushing substrate 17 having a thickness of about 100 to 200 (um) can be formed on the entire rear surface of the second electrode 15 to support the compound solar cell. The thickness of the bushing substrate 17 can be adjusted by changing the method of manufacturing the bushing substrate 17, the thickness of the electrode, or the electrode forming material.

 The bushing substrate 17 includes an insulating substrate 17b having a metal contact portion 30 formed in electrical contact with the rear electrode 15 and an insulating substrate 17b that exposes the metal contact portion 30. [ A front insulating layer 17a and a rear insulating layer 17c, which are formed on the front and back surfaces, respectively.

The insulating substrate 17b may be made of a high insulating film such as PET (polyethyleneterephthalate), PI (polyimide), or PE (polyethylene). The insulating base material 17 may include a metal contact portion 30 that makes electrical contact with the back electrode 15. [

The metal contact portion 30 may be formed of the same metal as the second electrode 17b for high conductivity with the second electrode 17b or copper (Cu) for easy processing, but is not limited thereto Various types of conductive materials can form the metal contacts 30.

More specifically, in one embodiment, the metal contact portion 30 may include a through hole 31 for exposing the rear electrode 15 and a conductive metal 33 formed in the through hole 31.

The through hole 31 is formed to penetrate through the insulating base material 17b and in a preferred form the conductive metal 33 may be arranged in the through hole 31 to conduct the front surface and the rear surface. For example, the conductive metal 33 may be formed to fill the through hole 31, or may be formed only partially on the wall surface of the through hole 31 without filling the entirety of the through hole 31.

The conductive metal 33 further includes a land 331 which is formed on the front surface and the rear surface of the insulating base material 17b facing the through hole 31 and connected to each other through the conductive metal 33 .

The land 331 may be formed as a single body with the conductive metal 33 or may be formed separately from the conductive metal 33.

The land 331 is connected to the conductive metal 33 formed on the through hole 31 so that the conductive metal 33 is extended to the front surface and the rear surface of the insulating substrate 17b. Accordingly, the conductive metal 331 including the land 331 can be formed to have an approximately "I" shape. As another example, the conductive metal 331 may be configured to have a horseshoe shape as illustrated in FIG. 6, and the conductive metal 33 including the land 331 may be formed to have various shapes without particular limitation There is a number.

Therefore, the conductive metal 33 formed on the cramped through hole 31 can be widely formed to the front surface and the rear surface of the insulating base material 17b, and as a result, the metal contact portion 30 is formed by the land 331, For example, the area of bonding with the second electrode 15 can be effectively increased.

The insulating films 17a and 17c formed on the front surface and the rear surface of the insulating substrate 17b include a conductive portion 40 electrically connected to the metal contact portion 30 of the insulating substrate 17b .

The insulating films 17a and 17c may be formed of an insulating material such as epoxy, silicon, or acrylate.

In one preferred form, the conductive portion 40 may comprise a via hole 41 that exposes the above-described metal contact portion 30, and a conductor 43 that fills the via hole and is electrically connected to the metal contact portion have.

Here, the conductor 43 may be made of a conductive material electrically and physically bonded to the metal contact portion 30, for example, a conductive adhesive or a solder may be thermally cured.

Here, the conductive adhesive is composed of the polymer base material and the conductive filler particles, and the conductive adhesive bonds and conducts between the members by mechanical and physical contact of the conductive fillers. The solder has a paste or cream phase formed by mixing the solder powder and flux. The solder powder melts above the melting point. It physically bonds with the base material while cooling, . The solder powder may be at least one selected from the group consisting of Sn-Cu, Sn-Ag, Sn-Ag-Cu, Sn-Ag-Bi, Sn- Sn-Bi system, and Sn-In system solder.

The bushing substrate 17 having such a structure may be formed to have a film shape and may be laminated to the second electrode 15 during the process of manufacturing a compound solar cell, for example, an epitaxial lift off (ELO) Can be bonded to the electrode (15).

In this way, when the bushing substrate 17 is bonded to the second electrode 15 by the laminating process, the melting point of the conductor (hereinafter referred to as the front conductor) constituting the conductive portion 40 of the front insulating film 17a Is preferably higher than the melting point of the conductor (hereinafter referred to as the rear conductor) constituting the conductive portion of the rear insulating film 17c.

If the melting point of the rear conductor is higher than the melting point of the front conductor, the front conductor may melt in the process of physically and electrically joining two neighboring solar cells using the rear conductor, which is not preferable.

On the other hand, Fig. 7 shows a rear view of the compound solar cell of this embodiment. As illustrated in FIG. 7, a bushing substrate 17 may be formed entirely over the rear electrode 15 at the rear side.

Then, the conductive part 40 can be formed discontinuously along one side of the compound solar cell while being exposed to the outside. Here, the number and shape of the conductive portions 40 can be variously changed in consideration of manufacturing processes and the like. As an example, it is also possible that the conductive part 40 is elongated along one side of the compound solar cell as shown.

As described above, only the conductive portion 40 is selectively exposed to the outside, and the inside thereof is covered and protected by the insulating film. Since the conductive portion 40 is disposed close to one side of the solar cell, it is easy to arrange the compound solar cells in a superposed manner.

As described above, in the bushing substrate 17 of this embodiment, since the metal contact portion 30, which forms the electrical contact with the second electrode 15, is formed inside the bushing substrate 17, It is possible to prevent the junction portion from being deteriorated even if the solar cell module is used for a long time in an external environment where the solar cell module 30 is not exposed to the outside and the environment is severely changed.

Hereinafter, referring to FIG. 8, a compound solar cell according to another embodiment of the present invention will be described.

Here, the constitution of the semiconductor layer 11, the front electrode 13 and the rear electrode 15 constituting the compound solar cell is the same as that of the above embodiment, and a detailed description thereof will be omitted.

In this embodiment, the bushing substrate 170 has a thickness of about 100 to 200 (um) to support the compound solar cell and may be formed on the entire rear surface of the second electrode 15. The thickness of the bushing substrate 17 can be adjusted by changing the method of manufacturing the bushing substrate 17, the thickness of the electrode, or the electrode forming material.

The bushing substrate 170 includes a conductive base material 170b and a front insulating film 170b having a metal contact portion 300 electrically connected to the conductive base material 170b and formed on the front and rear surfaces of the conductive base material 170b, (170a) and a rear insulating film (170c).

The conductive substrate 170b may be a foil preferably made of a conductive metal such as copper. In this embodiment, since the conductive base material 170b is formed over the entire surface like the second electrode 15, there is an advantage in that the contact resistance is reduced as compared with the case where the metal base material is locally formed.

In one example, the conductive base material 170b made of a metal foil is configured to protect the conductive base material 170b by disposing the insulating films 170a and 170c formed of an insulating material on the front surface and the rear surface, respectively.

The insulating material constituting the insulating films 170a and 170c is not particularly limited and may be composed of various insulating materials in consideration of the manufacturing process.

The insulating films 170a and 170c are preferably formed on the entire surface of the conductive base 170b and may include a metal contact portion 300 for a metal contact.

The metal contact portion 300 includes a via hole 310 for exposing the conductive base material 170b and a conductor 330 formed to be physically bonded to the conductive base material 170b via the via hole 310 .

Here, the conductor 330 may be formed of a conductive material electrically and physically bonded to the conductive base 170b. For example, a conductive adhesive or a solder may be thermally cured.

The bushing substrate 170 of this embodiment having such a configuration can be formed to have a film shape as described above and can be formed in the process of manufacturing a compound solar cell, for example, a second electrode (ELO) during an epitaxial lift- 15 and may be bonded to the second electrode 15.

When the bushing substrate 170 is bonded to the second electrode 15 by the laminating process, the melting point of the conductor (hereinafter referred to as the front conductor) constituting the conductive portion 300 of the front insulating film 170a Is preferably higher than the melting point of a conductor (hereinafter referred to as a rear conductor) constituting a conductive portion of the rear insulating film 170c.

If the melting point of the rear conductor is higher than the melting point of the front conductor, it is not preferable since the front conductor may cause a phase change in the process of forming the rear conductor to physically and electrically connect the two neighboring solar cells .

The arrangement of the metal contact portions 300 is the same as the arrangement of the conductive portions 40 described with reference to FIG. 7, and a detailed description thereof will be omitted.

A supporting substrate 51 for more firmly supporting the compound solar cell may be further disposed between the bushing substrate 17, 170 and the second electrode 15 formed as described above.

9, the front surface of the supporting substrate 51 may be entirely attached to the second electrode 15, and the rear surface may be attached to the front surface of the bushing substrate 17, 170 entirely. Here, the support substrate 51 may be laminated to the second electrode 15 or may be bonded through a non-conductive adhesive, and the bushing substrates 17 and 170 may also be laminated to the support substrate 51, Can be bonded.

Here, the non-conductive adhesive layer Ad may be formed from an adhesive having a higher bonding force than the conductive adhesive, such as PSA (Pressure Sensitive Adhesive) adhesive, Epoxy adhesive, Acrylate adhesive, Silicone adhesive, etc., but has no conductivity.

The support substrate 51 may further include a bonding portion 60 for electrically connecting the second electrode 15 and the metal contact portions 30 of the bushing substrates 17 and 170.

Preferably, the bonding portion 60 includes a via hole 61 that opens between the second electrode 15 and the metal contact portion 30, and a second electrode 15 and the metal contact portion 30 via the via hole 61, And a conductor 63 that electrically connects to each other.

Here, the conductor 63 may be formed from solder or a conductive adhesive. The support substrate 51 may be a PET (polyethylene terephthalate) film, more preferably a glass fiber reinforced PET film.

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, Of the right.

Claims (16)

A plurality of compound solar cells partially overlapping each other in the overlap region,
The plurality of compound solar cells may include,
A compound semiconductor layer;
A first electrode and a second electrode formed on the front surface and the rear surface of the compound semiconductor layer, respectively; And
And a bushing substrate formed on the rear surface of the second electrode, the bushing substrate exposing a part of the second electrode,
The bushing substrate
An insulating substrate 17b having a metal contact portion 30 formed in electrical contact with the second electrode,
And insulating films (17a, 17c) formed on both surfaces of the insulating base material to expose the metal contact portions,
The plurality of compound solar cells neighboring each other are electrically and physically connected by the metal contact portion disposed in the overlap region,
Wherein the metal contact portion includes a through hole exposing the second electrode, and a conductive metal formed in the through hole,
Wherein the insulating film includes a via hole exposing the metal contact portion at the front surface and a rear surface, and a conductive portion electrically connected to the metal contact portion, the conductive contact portion including a conductor electrically and physically bonded to the metal contact portion,
Wherein the conductor is formed of at least one of solder or a conductive adhesive. delete The method according to claim 1,
And a land formed on the front and back surfaces of the insulating base material facing the through hole, the land being connected to the conductive metal. The method of claim 3,
Wherein the conductive metal and the land are formed as a single body. 5. The method of claim 4,
Wherein the conductive metal and the land are made of the same conductive material as copper or the second electrode. The method according to claim 1,
And the metal contact portions are formed in a plurality of discontinuous manner in the overlap region. delete delete delete The method according to claim 1,
And a supporting substrate located between the second electrode and the bushing substrate and having a junction for electrically and physically connecting the second electrode and the metal contact. A plurality of compound solar cells partially overlapping each other in the overlap region,
The plurality of compound solar cells may include,
A compound semiconductor layer;
A first electrode and a second electrode formed on the front surface and the rear surface of the compound semiconductor layer, respectively; And
And a bushing substrate formed on the rear surface of the second electrode, the bushing substrate exposing a part of the second electrode,
The bushing substrate
A conductive substrate formed of a metal foil,
And an insulating layer formed on both surfaces of the conductive base, the insulating layer having a metal contact portion electrically connected to the conductive base,
Wherein the plurality of compound solar cells are electrically and physically connected by the metal contact portion disposed in the overlap region,
Wherein the metal contact portion includes a via hole exposing a part of the conductive base material on the front and rear surfaces of the conductive base material, and a conductor electrically and electrically connected to the conductive base material,
Wherein the conductor is formed of at least one of solder or a conductive adhesive. delete delete delete 12. The method of claim 11,
The metal contact portions are formed in a plurality of discontinuous manner in the overlap region. 12. The method of claim 11,
And a supporting substrate located between the second electrode and the bushing substrate and having a junction for electrically and physically connecting the second electrode and the metal contact.

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