KR101349847B1

KR101349847B1 - Solar Cell Package including By-Pass Diode

Info

Publication number: KR101349847B1
Application number: KR1020120062979A
Authority: KR
Inventors: 조우진
Original assignee: 희성전자 주식회사
Priority date: 2012-06-13
Filing date: 2012-06-13
Publication date: 2014-01-27
Also published as: KR20130139493A

Abstract

The present invention relates to a compound solar cell having a vertical structure in which a bypass diode provided to prevent reverse voltage of the solar cell is integrally formed with the solar cell. The solar cell package of the present invention includes a pair of insulating layers. A PCB substrate having electrodes; A bypass diode device mounted on one electrode of the PCB substrate; A junction layer formed on an upper surface of the bypass diode element; A solar cell bonded to an upper surface of the bypass diode device via the junction layer; And a bonding wire connecting the electrodes of the diode device and the solar cell to the electrodes of the PCB substrate.

Description

Bypass Diode Integrated Solar Cell Package {Solar Cell Package including By-Pass Diode}

The present invention relates to a solar cell, and more particularly, to a compound solar cell having a vertical structure in which a bypass diode provided to prevent a reverse voltage of the solar cell is integrally formed with the solar cell.

Solar cell is a key element of photovoltaic power generation that directly converts sunlight into electricity. When solar light is incident on the light absorption layer, electron-hole pairs are generated and electricity is generated by using the electromotive force. Element. Solar cells can be broadly classified into silicon-based, compound-based and organic-based solar cells according to the materials used. In addition, silicon-based solar cells may be classified into crystalline silicon (C-Si) solar cells and amorphous silicon (A-Si) solar cells according to the phase of the semiconductor.

These solar cells have a module structure in which a plurality of solar cells are connected in series to obtain a higher voltage because the output voltage is relatively low, such as several volts. At this time, when a defect occurs in one cell or is covered by a shadow, the defective cell may limit the total module current and destroy the device. To prevent this, a bypass diode is connected to each cell.

1 is a circuit diagram illustrating a general structure of a solar cell module having a bypass diode, and FIG. 2 is a perspective view schematically illustrating the solar cell package of FIG. 1 according to the related art. In the solar cell module, as shown in FIG. 1, a plurality of solar cells 10 are connected in series, and each solar cell 10 has a bypass diode 20 connected in parallel to prevent reverse bias. . In this case, the bypass diode 20 allows the normal output by another series group to be normally performed even if any one of the cells connected in series in the solar cell module array fails. Meanwhile, as shown in FIG. 2, in the solar cell package 1 according to the related art, the solar cell 10 is mounted by wire 32 bonding on a metal PCB substrate 30, and a discrete bypass diode 20 forms a structure in which the wire 32 is bonded on one side in the horizontal direction of the solar cell 10. At this time, the metal PCB substrate 30 is divided into a pair of electrodes by the insulating film 31.

In the solar cell package 1 according to the related art, a bypass diode 20 of a discrete element is mounted in the horizontal direction of the solar cell 10 so that one solar cell package 1 occupies a large area. There is a problem. This will eventually limit the number of solar cells 10 that can be formed in a predetermined area. In addition, since the bypass diode 20 of the discrete elements must be connected in parallel through soldering or the like, together with the bonding of the solar cell 10 on the PCB board 30 having a small area, the work is difficult and productivity is reduced. There is this.

The present invention has been proposed to solve the above problems, an object of the present invention is to provide a solar cell package that can form a large number of solar cells per unit area by forming a bypass diode and a solar cell in a vertical structure. It is done.

Another object of the present invention is to provide a bypass diode-integrated solar cell package having a structure capable of improving productivity by manufacturing a thin-film type bypass diode and a solar cell using a semiconductor manufacturing process.

The solar cell package of the present invention for achieving the above object is a PCB substrate having a pair of electrodes separated by an insulating film; A bypass diode device mounted on one electrode of the PCB substrate; A junction layer formed on an upper surface of the bypass diode element; A solar cell bonded to an upper surface of the bypass diode device via the junction layer; And a bonding wire connecting the electrodes of the diode device and the solar cell to the electrodes of the PCB substrate.

Here, the junction layer is characterized by consisting of a junction layer of a metal layer formed on the upper surface of the bypass diode element and an amorphous silicon layer formed on the lower surface of the solar cell.

In the present invention having the above configuration, the bypass diode and the solar cell are formed in a vertical structure, whereby a large number of solar cell can be formed per unit area. In addition, the bypass diode may be formed into a thin film using a semiconductor manufacturing process and bonded to the solar cell, thereby improving productivity.

1 is a circuit diagram showing a general structure of a solar cell provided with a bypass diode,
Figure 2 is a perspective view schematically showing a solar cell according to the prior art,
3 is a perspective view showing a solar cell package according to an embodiment of the present invention,
4 is a cross-sectional view showing a solar cell package of FIG.
5 is a circuit diagram illustrating a solar cell package of FIG. 3, and
FIG. 6 is a view illustrating a bonding process between a bypass diode and a solar cell of the solar cell package of FIG. 3.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a perspective view illustrating a solar cell package according to an embodiment of the present invention, FIG. 4 is a cross-sectional view illustrating the solar cell package of FIG. 3, and FIG. 5 is a circuit diagram illustrating the solar cell package of FIG. 3. As can be seen in Figures 3 and 4, the solar cell package of the present invention is a bypass diode 110 layer type on the PCB substrate 130, the solar cell on top of the bypass diode 110 layer. It forms a structure in which 120 layers are formed. That is, the present invention forms a structure in which the bypass diode 110 and the solar cell 120 are vertically bonded.

Specifically, the PCB substrate 130 is printed with various circuit patterns for power connection, and is divided into a pair of electrodes 130a and 130b having different potentials by the insulating layer 131. The bypass diode 110 and the solar cell 120 module are formed on one electrode 130a of the PCB substrate 130, and the wire 132 is bonded to the other electrode 130b to be electrically connected. Connected.

The bypass diode 110 is turned on when the reverse voltage is applied to the solar cell 120 so that the solar cell 120 is off, so that the current can continue to flow, and in parallel to the solar cell 120 Connected. The bypass diode 110 is formed of a semiconductor device having a pn junction, and a structure in which the lower electrode 111, the n-type semiconductor layer 112, the p-type semiconductor layer 113, and the upper electrode 114 are sequentially stacked. Can be achieved. In particular, in the present invention, the upper electrode 114 is formed on one side of the upper surface of the p-type semiconductor layer 113, the metal layer 115 for bonding to the solar cell 120 is the remaining p-type semiconductor layer ( 113) is formed on the upper surface. In this case, the metal layer 115 may be formed on the upper surface of the p-type semiconductor layer 113 via the insulating layer 116 to insulate the solar cell 120 formed on the bypass diode 110. Do.

The solar cell 120 is a semiconductor device that absorbs light energy by sunlight to generate electrons and hole pairs, thereby generating a current due to the movement of electrons and holes. The solar cell 120 may be composed of various types of solar cells, such as silicon-based, compound-based, or organic-based solar cells. For example, the present invention is composed of a solar cell using a III-V semiconductor compound as a light absorption layer. That is, as shown, the light absorption layer is composed of a first light absorption layer 122 of a Ge cell as a substrate, a second light absorption layer 123 of a GaAS cell as an intermediate layer and a third light absorption layer 124 of a GaInP cell as an upper layer. The anti-reflective coating (ARC) 125 may be formed on the upper surface of the third light absorbing layer 124 to prevent reflection of sunlight. In addition, one side of the first light absorbing layer 122 is mesa-etched to form a first electrode 126, and a second electrode 127 is formed on one side of the upper surface of the third light absorbing layer 124 together with the anti-reflection film 125. . In this case, the second electrode 127 may be formed through the p-GaAs cell 127a doped with p +.

Here, the first light absorbing layer 122, which is a Ge cell layer, absorbs light in the wavelength bands of the infrared and visible light regions as a substrate of the light absorbing layer, and the second light absorbing layer 123, which is a GaAS cell layer, is formed around a blue series. The light absorbs light in the visible region, and the third light absorbing layer 124, which is a GaInP cell layer, absorbs the ultraviolet light and the light in the visible region. In addition, the anti-reflection film 125 serves to improve the light absorption efficiency by reducing the reflection of the sunlight absorbed by the light absorption layer (122, 123, 124). The anti-reflection film 125 may be formed of a material having high light transmittance and high refractive index. For example, a ZnS thin film, a MgF ₂ thin film, or a thin film of Mg-Zn-F compound may be formed in a single or multilayer structure. The first electrode 126 and the second electrode 127 collect electrons and holes generated in the light absorption layer to allow the flow of current. The p-GaAs cell 127a formed on the second electrode 127 induces concentration of electrons so that the electrons can smoothly move to the second electrode 127.

The bypass diode 110 and the solar cell 120 having the above structure are stacked in a vertical structure at one electrode 130a of the PCB substrate 130, and the upper electrode 114 and the solar cell of the bypass diode are stacked. The second electrode 127 of the cell is bonded and connected to the other electrode 130b of the PCB substrate 130 by a wire 132. In addition, the first electrode 126 of the solar cell 120 is bonded by a wire 132 to one electrode 130a of the PCB substrate 130.

In the solar cell package 100 having the above structure, even when the solar cell 120 is damaged or a reverse bias is applied, current may flow through both terminals. The bypass diode 110 has a reverse bias voltage applied to the solar cell 120 so that the current flows through the solar cell 120 when the flow of current through the solar cell 120 is blocked. Because it forms. That is, as shown in (a) of FIG. 5, when a forward voltage due to sunlight is normally generated in the solar cell 120, current flows through the solar cell 120, but in (b) As shown in the drawing, when an abnormal reverse voltage is applied to the solar cell 120 due to a shadow or destruction of an element, the bypass diode 110 is turned on so that current can flow therethrough. Even if any one of the solar cells 120 connected in series by the bypass diode 110 is turned off, the entire current flow can be maintained.

FIG. 6 is a view illustrating a bonding process between a bypass diode and a solar cell of the solar cell package of FIG. 3.

The solar cell package of the present invention is manufactured by bonding a solar cell substrate prepared by epitaxially growing a compound of group III-V to a diode substrate having a p-n junction structure in a vertical direction. At this time, the junction of the solar cell 120 and the bypass diode may be made of a hetero substrate bonding process. That is, as shown in FIG. 6, after forming the solar cell 120 on an amorphous silicon substrate, the solar cell 120 is bonded to an upper surface of the bypass diode 110 fabricated in a separate process. The metal layer 115 is formed on the upper surface of the bypass diode 110 for the junction. When the amorphous silicon layer 121 and the metal layer 115 are adhered to each other by applying a predetermined temperature and pressure, the upper and lower layers are bonded at the contact surface between the amorphous silicon 121 and the metal layer 115.

In addition, the bypass diode 110 and the solar cell 120 module, each of which has a vertical junction, are mounted on the PCB substrate 130 by a surface mounting process, and each of the bypass diode 110 and the solar cell 120 is mounted. The electrodes 114, 126, and 127 are connected by wire bonding to the electrodes 130a and 130b of the PCB substrate. In this case, the bypass diode 110 may be adhered to the PCB substrate 130 using the adhesive 133.

Since the bypass diode 110 is coupled to the solar cell 120 in a vertical structure, the solar cell package 100 manufactured by the above process may reduce the area occupied by the solar cell package 100 on the substrate. A large number of solar cell packages 100 may be installed for the same area. In the description of the present invention, the solar cell package having a vertical structure has illustrated a solar cell using a compound of group III-V, but is not limited thereto and may be applied to various types of solar cell that can be bonded in a vertical structure with a bypass diode. It can also be applied.

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.

100: solar cell package
110: bypass diode 111: lower electrode
112: n-type semiconductor layer 113: p-type semiconductor layer
114: upper electrode 115: metal layer
120: solar cell 121: amorphous silicon layer
122: first light absorbing layer 123: second light absorbing layer
124: third light absorption layer 125: antireflection film
126: first electrode 127: second electrode
130: PCB substrate

Claims

A PCB substrate having a pair of electrodes separated by an insulating film;
A bypass diode device mounted on one electrode of the PCB substrate;
A junction layer formed on an upper surface of the bypass diode element;
A solar cell bonded to an upper surface of the bypass diode device via the junction layer; And
And a bonding wire connecting the electrodes of the diode device and the solar cell to the electrodes of the PCB substrate.
The bonding layer,
And a junction layer formed of a metal layer formed on an upper surface of the bypass diode element and an amorphous silicon layer formed on a lower surface of the solar cell.

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