KR20190043291A - Solar cell module using divided cell and conductive foil - Google Patents

Abstract

The present invention relates to a photovoltaic module using a divided cell and a foil capable of increasing a light receiving area of a photovoltaic cell without generating a step between divided cells and improving photoelectric conversion efficiency of a photovoltaic cell by dividing a normal cell into a plurality of divided cells and constituting a photovoltaic module by electrically connecting a plurality of divided cells using a foil-type conductor. In the photovoltaic module according to the present invention, a plurality of cells divided from a normal cell are arranged to face each other along a longitudinal direction. The divided cells include first and second divided cells neighbored each other. A front electrode of the first divided cell and a rear electrode of the second divided cell are electrically connected by the foil-type conductor arranged in a longitudinal direction of the divided cell.

Description

[0001] The present invention relates to a solar cell module using a divided cell and a foil,

The present invention relates to a solar cell module using a divided cell and a foil, and more particularly, to a solar cell module using a divided cell and a foil, and more particularly to a solar cell module in which a normal cell is divided into a plurality of divided cells and a plurality of divided cells are electrically connected To a photovoltaic module using divided cells and foils capable of enhancing photoelectric conversion efficiency of a solar cell while increasing the light receiving area of the solar cell without generating a step between the divided cells.

The solar cell module is a device for receiving and photoelectrically converting sunlight, and is made up of a plurality of solar cells. Each solar cell constituting the solar cell module may be referred to as a p-n junction diode.

The process of converting sunlight into electricity by solar cells is as follows. When sunlight is incident on the p-n junction of the solar cell, an electron-hole pair is generated, and electrons are transferred to the n-type semiconductor layer and holes are transferred to the p-type semiconductor layer by the electric field to generate photovoltaic power between the p-n junctions. In such a state, if a solar cell is connected to both ends of the solar cell, a current can flow to produce electric power. The front and rear surfaces of the solar cell are provided with front and back electrodes for collecting electrons and holes, respectively.

In general, the front electrode of the first solar cell 110 is connected to the rear electrode of the neighboring second solar cell 120 through an interconnector (not shown) 130 (see Fig. 1).

The interconnector for electrically connecting neighboring solar cells is made of a conductor having a certain width and thickness. The shape for connecting neighboring solar cells is a ribbon shape, and a common interconnector is also referred to as a ribbon.

As described above, since the ribbon-shaped interconnector has a certain width and thickness, for example, a width of about 1.5 mm and a thickness of about 270 탆, a certain area of the solar cell can not be covered by the interconnector. Since the solar cell receives the sunlight and converts it into electricity, the decrease in the light receiving area of the solar cell means a decrease in the photoelectric conversion efficiency.

In recent years, there has been proposed a technique of replacing a ribbon-type interconnection with a wire-type interconnection in order to solve the problem of reducing the light receiving area by the interconnection and to improve the efficiency of the solar cell. Further, a technique has been proposed in which a normal cell is divided into a plurality of divided cells, and a plurality of divided cells are connected in a tiered stacking manner to reduce a light receiving area and improve a module output.

In the tile-laminated solar cell module, three or more divided cells are stacked one over the other like a trough, and the front electrodes and the rear electrodes of neighboring divided cells are electrically connected by using a conductive adhesive.

However, in such a conventional tile lamination type solar cell module, a step difference is generated due to overlapping in a tiled fashion, so that the total thickness of the solar cell module is increased, and during subsequent processes such as lamination and during module use A local stress is applied to the stepped portion due to the losing pressure. There is a high possibility that fine cracks are formed in the cell edge portion in the process of scribing and separating the cells, and there is a problem that the possibility of crack generation due to local stress becomes greater because the cells are bonded to each other at the cell edge portion.

In addition, a conductive inorganic adhesive or a conductive organic adhesive such as Ag paste is used for electrical connection between neighboring divided cells. In the case of applying the Ag paste, the Ag paste is required to be fired, whereas the solar cell tableting process affects the electrical characteristics of the cell Since the low-temperature firing Ag paste is separately required, there is a fear of an increase in manufacturing cost. Conductive organic adhesives also require special materials with low contact resistance, which increases the manufacturing cost.

In addition, when a conductive inorganic adhesive such as an Ag paste or a conductive organic adhesive is applied, it is not easy to separate the bonding state between cells when repairing a broken cell during use. In the case of a conductive organic adhesive, And reliability such as moisture resistance may be deteriorated.

Korean Patent No. 1138174

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide a solar cell module in which a normal cell is divided into a plurality of divided cells and a plurality of divided cells are electrically connected using a foil- The present invention provides a solar cell module using a divided cell and a foil, which can increase the light receiving area of the solar cell and improve the photoelectric conversion efficiency of the solar cell without generating a step between the divided cells.

According to an aspect of the present invention, there is provided a solar cell module using a divided cell and a foil, wherein a plurality of divided cells divided from a normal cell are arranged to face each other along the longitudinal direction, and the plurality of divided cells are arranged adjacent to each other Wherein the front electrode of the first divided cell and the rear electrode of the second divided cell are electrically connected by a conductive foil disposed along the longitudinal direction of the divided cells, .

Each of the divided cells has a bus bar electrode at one end, and the conductive foil covers the bus bar electrode provided at one end of the divided cells.

Wherein the normal cell has a structure in which a plurality of finger electrodes are spaced and arranged over the entire substrate and three to ten bus bar electrodes are provided in a form in which a plurality of finger electrodes are orthogonal to each other, And one bus bar electrode is provided on one end side of the divided cells.

A diffuse reflection induction pattern may be provided on the conductive foil in the form of a projection to induce irregular reflection. The plurality of divided cells are divided into three to ten normal cells. In addition, the conductive foil, the front electrode, the conductive foil and the rear electrode are connected by soldering, and the conductive foil may be coated with lead.

The amount of current produced by each divided cell is the same or falls within a tolerance range. Further, the areas of the divided cells are equal to each other.

The solar cell module using the divided cell and the foil according to the present invention has the following effects.

The light receiving area of the solar cell can be increased because the solar cell module is constituted by a plurality of divided cells and the conductive foil is provided only in the adjacent region between the divided cells and the divided cells.

In addition, by using a foil made of Al, Cu or the like and connecting the cells using the soldering process used in the conventional solar cell process, it is possible to reduce the cost of developing and manufacturing special materials such as conductive adhesive, thereby reducing the material cost. Also, when the string is repaired, heat can be applied to the soldered portion to easily disconnect the connected cells, so that the damaged cell can be easily replaced. In addition, since a thin conductive foil having a thickness of 200 탆 or less is applied, it is possible to reduce a step caused by overlapping of a cell and a cell, and to avoid a cell edge having a high frequency of micro crack occurrence even if a step is formed between the foil and the cell The possibility of cell cracking can be reduced.

In addition, as the conductive foil of the thin film is applied, the conductive foil absorbs the mechanical stress and the thermal stress when the cell is deformed according to the temperature change, so that the damage of the solar cell can be further suppressed. In addition, as the area of the divided cells or the electrode pattern is controlled so that each divided cell produces the same level of current, the current loss between the divided cells can be minimized.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a conventional solar cell module.
2 is a schematic view of a solar cell module using a divided cell and a foil according to an embodiment of the present invention.

The present invention discloses a solar cell module composed of a plurality of divided cells. The present invention also provides a solar cell module in which a plurality of divided cells are electrically connected by a conductive foil.

In the present invention, the term 'divided cell' refers to a plurality of normal solar cell units (hereinafter, referred to as 'normal cells'). A typical normal cell is a solar cell having a pn junction structure and an electrode structure completed by applying a solar cell process to a silicon substrate having a size of about 6 inches (about 156 mm x 156 mm) in width and 6 inches. Which means that such a normal cell is divided into a plurality of cells.

In the solar cell module according to the present invention, a plurality of divided cells are electrically connected by a conductive foil. The conductive foil electrically connects the front electrode of the first divided cell and the rear electrode of the second divided cell. More specifically, the bus bar electrode on the front face of the first divided cell and the bus bar electrode on the rear face of the second divided cell can be connected by the conductive foil.

The conductive foil of the present invention is disposed on one end side and the other end side of the divided cells so that a bus provided on one end side of the front surface of the first divided cell, And a bus bar electrode provided on one end side of the rear surface of the second divided cell. As the conductive foil is provided on both end sides of the divided cells, the light receiving area of the solar cell can be increased.

On the other hand, in electrically connecting a plurality of divided cells, the currents produced in the respective divided cells must be the same or have similar levels within an error range. If the production currents generated by the respective divided cells are different from each other, the efficiency of the solar cell is lowered because it is adjusted to the divided cells producing the lowest current. Taking this into consideration, the area and the electrode pattern are designed so that a plurality of divided cells applied to the present invention produce a similar level of current within the same current or error range.

The silicon substrate on which the normal cell is implemented, that is, the wafer, has a square shape, but has an octagonal shape because the corner portion is chamfered. Since the wafer of the normal cell does not have a perfect square shape, if the normal cell is divided into a uniform length (or width), the area of each divided cell becomes different. That is, in the case of a uniformly divided normal cell, the divided cells including the border and the divided cells including the inner side are different from each other.

The difference in the areas of the divided cells means the difference in the light receiving areas, and the difference in the light receiving areas means that the current amounts produced in the respective divided cells are different from each other. In consideration of this, the present invention makes each of the divided cells constituting the solar cell module have the same area. From another point of view, it is also possible to divide the normal cells by equally dividing, but also to make the amount of current produced in each divided cell through the design of the electrode pattern of each divided cell equal.

Hereinafter, a solar cell module using a divided cell and a foil according to an embodiment of the present invention will be described in detail with reference to the drawings.

2, a solar cell module using a divided cell and a foil according to an embodiment of the present invention includes a plurality of divided cells 10 including a first divided cell 11 and a second divided cell 12, And are electrically connected to each other via the plurality of conductive foils 30.

The normal cell is a silicon substrate having a size of about 6 inches (about 156 mm x 156 mm) and a width of about 6 inches (about 156 mm x 156 mm) And a pn junction structure and an electrode structure are completed. The size of the normal cell may be 5 to 8 inches in width and 6 inches in size. Since the normal cell is divided into 3 to 10 cells, the length of the long side and the short side of the divided cell 10 have a ratio of 3 to 10: 1.

The normal cell includes a front electrode 20 and a rear electrode (not shown). The front electrode 20 is provided on the front surface of the normal cell to collect carriers (for example, electrons) generated inside the solar cell substrate, and the rear electrode is provided on the rear surface of the normal cell, For example, holes). The front electrode 20 is composed of a finger electrode 22 and a bus bar electrode 21. The finger electrodes 22 are arranged parallel to the entire surface of the substrate at regular intervals, and the bus bar electrodes 21 are arranged orthogonal to the finger electrodes 22 on the entire surface of the substrate. 3 to 10 bus bar electrodes 21 may be arranged at regular intervals. The rear electrode may be a combination of a finger electrode and a bus bar electrode as in the case of the front electrode 20. In another embodiment, the rear electrode may be formed of a combination of an Al electrode and a bus bar electrode for inducing formation of a back surface filed It is possible.

A divided cell 10 divided from a normal cell having such a structure has one bus bar electrode 21. As described above, a normal cell has a structure in which a plurality of finger electrodes 22 are spaced apart from one another over the entire substrate, and three to ten bus bar electrodes 21 are provided in a shape in which a plurality of finger electrodes 22 are orthogonal to each other The normal cells are divided such that one bus bar electrode 21 is included in each of the divided cells 10. [ Each bus bar electrode 21 is provided with a plurality of finger electrodes 22, and the bus bar electrode 21 is provided on one end of the divided cell 10, The electrodes 21 are arranged along the longitudinal direction of the divided cells 10 (the direction orthogonal to the finger electrodes 22).

Each of the divided cells 10 having a structure in which one bus bar electrode 21 is arranged along the longitudinal direction of the divided cell 10 and a plurality of finger electrodes 22 is connected to the bus bar electrode 21 Respectively. The first divided cell 11 and the second divided cell 12 are electrically connected by the conductive foil 30, for example, two divided cells 10 disposed adjacent to each other.

Specifically, the conductive foil 30 is disposed in the longitudinal direction of the divided cells 10 (in a direction orthogonal to the finger electrodes 22) like the bus bar electrode 21, And the conductive foil 30 is bent between the first divided cell 11 and the second divided cell 12 so as to be electrically connected to the rear part of the second divided cell 12 And is electrically connected to the electrode. As described above, the bus bar electrode 21 is provided at one end of the divided cell 10, and the conductive foil 30 covers the bus bar electrode 21 disposed at one end of the divided cell 10 So that it is possible to minimize the reduction of the light receiving area by the conductive foil 30, since the conductive foil 30 is disposed only in the vicinity of the first divided cell 11 and the second divided cell 12. Further, as the thin conductive foil 30 is applied, the damage of the solar cell can be suppressed as the conductive foil 30 absorbs the mechanical stress and the thermal stress during the cell deformation due to the temperature change.

Meanwhile, the conductive foil 30 may be formed using the same material as the conventional ribbon connector, or may be formed of a copper foil. The connection between the conductive foil 30 and the front electrode 20 and the connection between the conductive foil 30 and the rear electrode may be performed by a soldering method. In this case, the conductive foil 30 may be coated with lead. In addition, in order to maximize the reflection of light, the conductive foil 30 may be provided with a diffuse reflection inducing pattern in the form of protrusions for inducing irregular reflection.

In the present invention, the foil made of Al, Cu, or the like is used and the cell is connected by using the soldering process used in the conventional solar cell process, thereby reducing the cost of developing and manufacturing a special material such as a conductive adhesive, . Also, when the string is repaired, heat can be applied to the soldered portion to easily disconnect the connected cells, so that the damaged cell can be easily replaced. In addition, since a thin conductive foil having a thickness of 200 탆 or less is applied, it is possible to reduce a step caused by overlapping of a cell and a cell, and to avoid a cell edge having a high frequency of micro crack occurrence even if a step is formed between the foil and the cell The possibility of cell cracking can be reduced.

The normal cell is divided into a form in which the bus bar electrode 21 is provided on one end side of the divided cell 10 in the above embodiment. However, the first divided cell 11 and the second divided cell The electrode structure of the divided cell 10 is not limited under the premise of the structure in which the conductive foil 30 is disposed only in the adjacent region of the cell 12. The structure in which the bus bar electrode 21 is provided on one end side of the divided cell 10 is the best embodiment according to the present invention. However, the conductive foil 30 is not the bus bar electrode 21 but the finger electrode 22 In this case, the finger electrode 22 and the conductive foil 30 may be connected to each other through a conductive pad connected to the finger electrode 22.

In addition, in order to increase the efficiency of the solar cell, the following points need to be considered. As described above, a normal cell is a solar cell having a pn junction structure and an electrode structure formed by applying a solar cell process to a silicon substrate having a size of about 6 inches (about 156 mm x 156 mm) in width and about 6 inches. As the corners are chamfered to form an octagon, the normal cells are also octagonal.

When the octagonal normal cells are uniformly divided, the divided cells 10 including the rims of the normal cells and the divided cells 10 including the inner regions of the normal cells are different from each other in area, This is because the edge of the normal cell contains the chamfer portion.

Therefore, in order to set the amount of current produced by each of the divided cells 10 to be the same (or a similar level within a tolerance range), the area of each of the divided cells 10 should be the same. For this purpose, the normal cells should be divided in consideration of the area reduced by the chamfer when the normal cells are divided. In this case, normal cells are not divided equally.

10: split cell 11: first divided cell
12: second divided cell 20: front electrode
21: bus bar electrode 22: finger electrode
30: conductive foil

Claims (8)

A plurality of divided cells divided from a normal cell are arranged to face each other along the longitudinal direction,
Wherein the plurality of divided cells include a first divided cell and a second divided cell arranged adjacent to each other,
Wherein the front electrode of the first divided cell and the rear electrode of the second divided cell are electrically connected by a conductive foil disposed along the longitudinal direction of the divided cells.
2. The plasma display panel as claimed in claim 1, wherein each of the divided cells has a bus bar electrode at one end, and the conductive foil covers the bus bar electrode provided at one end of the divided cells. .
2. The plasma display panel of claim 1, wherein the normal cells have a structure in which a plurality of finger electrodes are spaced apart from one another over the entire substrate, and three to ten bus bar electrodes are provided orthogonal to the plurality of finger electrodes,
Wherein the divided cells divided from the normal cell include one bus bar electrode and one bus bar electrode is provided at one end of the divided cell.
The solar cell module according to claim 1, wherein the conductive foil is provided with a diffuse reflection inducing pattern in the form of a protrusion for inducing irregular reflection.
The solar cell module according to claim 1, wherein the plurality of divided cells are divided into three to ten normal cells.
The solar cell module according to claim 1, wherein the conductive foil, the front electrode, the conductive foil and the rear electrode are connected by soldering, and the conductive foil is coated with lead.
The tile-laminated solar cell module according to claim 1, wherein a current amount produced by each of the divided cells is the same or within a tolerance range.
The solar cell module according to claim 1, wherein each of the divided cells has the same area.

Images