JP2004200515A - Solar cell module - Google Patents

Abstract

Provided is a high-performance solar cell module that reduces electric resistance due to a connection tab at a portion that is not on an electrode such as between a plurality of solar cell elements, prevents a decrease in output of the solar cell module, and provides a high-performance solar cell module.
A solar cell module in which a plurality of solar cell elements having electrodes on the front and back surfaces are electrically connected by connection tabs and arranged on the back side of a light-transmitting substrate. The widths of the connection tabs 17 and 18 between the electrodes 3 and 4 of the plurality of solar cell elements 1 and 2 are made wider or thicker than the widths on the electrodes 3 and 4.
[Selection] Fig. 2

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a solar cell module, and more particularly to a solar cell module in which a plurality of solar cell elements are electrically connected by connection tabs.
[0002]
[Prior art]
Solar cell elements are often manufactured using a single crystal silicon substrate or a polycrystalline silicon substrate. For this reason, the solar cell element is vulnerable to physical impact, and when the solar cell is installed outdoors, it is necessary to protect it from rain etc. Therefore, the solar cell element is made of a translucent substrate and an ethylene vinyl acetate copolymer ( It is common practice to create a solar cell module by enclosing it with a filler mainly containing EVA) or the like.
[0003]
In this solar cell module, since one solar cell element has a small electric output, a plurality of solar cell elements are usually connected in series and parallel, so that a practical predetermined electric output can be obtained from the solar cell module. .
[0004]
6 and 7 are views showing a state where a plurality of solar cell elements are connected. FIG. 6 is a cross-sectional view of a connection portion between two solar cell elements, and FIG. 7 is a diagram illustrating a light receiving surface side where the two solar cell elements are connected.
[0005]
6 and 7, reference numerals 1 and 2 denote solar cell elements, reference numerals 3 and 4 denote light receiving surface side bus bar electrodes, reference numerals 5 and 6 denote connection tabs, reference numeral 7 denotes light receiving surface side finger electrodes, reference numeral 8 denotes a P-type substrate, and reference numeral 9 denotes an N type. The impurity diffusion layer 10 is a high-concentration P-type impurity diffusion layer, and 11 is a back-side busbar electrode.
[0006]
The solar cell elements 1 and 2 have the following structure. An N-type impurity diffusion layer 9 is formed by thermally diffusing an N-type impurity such as phosphorus on one main surface of a single-crystal silicon or polycrystal silicon P-type substrate 8 having a thickness of about 0.3 mm and a size of about 150 mm square. Then, a high-concentration P-type impurity diffusion layer 10 is formed by baking a P-type impurity such as aluminum on the other main surface. Further, an anti-reflection film (not shown) is formed of silicon nitride or the like to suppress light reflection on the N-type impurity diffusion layer 9 serving as a light receiving surface, and then a silver paste is screen-printed on the light receiving surface side and the back side. To form an electrode.
[0007]
The electrodes are composed of busbar electrodes and finger electrodes on both the light receiving surface side and the back surface side. For example, on the light-receiving surface, the finger electrodes 7 are about 0.2 mm in width, and many finger electrodes 7 are formed in parallel with the sides of the solar cell element to collect light-generating carriers. The busbar electrodes 3, 4 are formed to have a width of about 2 mm for collecting the collected carriers and attaching the connection tabs 5, 6, and are formed two to three so as to intersect the finger electrodes 7 vertically. Lastly, all of the electrodes are solder-coated to protect the electrode portions and to facilitate attachment of the connection tabs 5,6. In the solar cell element thus manufactured, the light receiving surface side is a minus side, and the back surface is a plus side.
[0008]
The connection tabs 5 and 6 are usually formed by cutting the entire surface of a copper foil having a thickness of about 0.1 mm and a width of 2 mm with solder to a predetermined length.
[0009]
Attachment of the connection tabs 5 and 6 to the solar cell element 1 is performed such that the connection tabs 5 and 6 cut to a predetermined length are not hidden on the light-receiving side busbar electrodes 3 and 4 of the solar cell element. Deploy. Next, the connection tabs 5, 6 are connected to the light-receiving-side busbar electrodes 3, 4 of the solar cell element by pressing the connection tabs 5, 6 against the light-receiving-side busbar electrodes 3, 4 with a soldering iron. Further, the front and back of the solar cell element 1 to which the connection tabs 5 and 6 are connected are turned upside down, and the connection tab 5 is similarly connected to the back side bus bar electrode 11 of the solar cell element 2 as shown in FIG. (See Patent Document 1)
Prior art document information related to the invention of this application includes the following.
[0010]
[Patent Document 1]
Japanese Patent Publication No. 11-318820
[Problems to be solved by the invention]
The width and thickness of the connection tabs 5, 6 used for connecting the solar cell elements 1, 2 as described above are constant over the entire length. For this reason, considering the series resistance of the connected solar cell elements 1 and 2, the portions where the connection tabs 5 and 6 on the light receiving surface side and the back surface side of the solar cell elements 1 and 2 are connected to the electrodes 3 and 4 are electrodes. Although there are solders and connection tabs 5 and 6 on the electrodes 3 and 4 and the connection tabs 5 and 6, portions that are not connected to the electrodes 3 and 4 such as between the solar cell elements 1 and 2 are only the connection tabs 5 and 6. Therefore, the electrical resistance of the portion where the connection tabs 5, 6 and the electrode are not connected is considerably higher than that of the portion where the connection tabs 5, 6 and the electrodes 3, 4 of the solar cell elements 1, 2 are connected.
[0012]
For this reason, in the entire solar cell module, there is a problem that the electric output is reduced due to the influence of the electric resistance of the portion where the connection tabs 5 and 6 and the electrodes 3 and 4 are not connected.
[0013]
The present invention has been made in view of such a problem, and an object of the present invention is to reduce the electric resistance due to a connection tab on a portion that is not on an electrode, such as between solar cell elements, and to reduce the output of a solar cell module. And providing a high-performance solar cell module.
[0014]
[Means for Solving the Problems]
In view of the above problems, in the present invention, in a solar cell module in which a plurality of solar cell elements having electrodes on the front and back surfaces are electrically connected by connection tabs and arranged on the back side of the light-transmitting substrate, the plurality of solar cell elements The width of the connection tab between the electrodes is wider than the width on the electrodes.
[0015]
Also, in a solar cell module in which a plurality of solar cell elements having electrodes on the front and back surfaces are electrically connected by connection tabs and arranged on the back side of the light-transmitting substrate, a connection tab between the electrodes of the plurality of solar cell elements is provided. Is thicker than the thickness on the electrode.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a diagram showing an example of the structure of a solar cell module manufactured by the method of the present invention. In FIG. 1, 12 is a translucent substrate, 13 and 15 are fillers, 14 is a plurality of solar cell elements connected by connection tabs, and 16 is a back surface material.
[0017]
As the translucent substrate 12, a white plate tempered glass having a thickness of about 3 to 5 mm is often used.
[0018]
The solar cell element 14 is made of, for example, a single-crystal silicon or polycrystalline silicon substrate having a thickness of about 0.3 mm, and its approximate size is, for example, about 150 mm square in a polycrystalline silicon solar cell. When producing a solar cell module, the electrodes of the solar cell element 14 are connected to connection tabs 17 such as solder-plated copper foil, and the connection tabs are further connected so that a predetermined electric output is generated from the solar cell module. At 17, a solar cell element 14 connected in series and parallel is used.
[0019]
As described above, in addition to the ethylene vinyl acetate copolymer (EVA), a filler mainly containing polyvinyl butyral (PVB) or the like is often used as the fillers 13 and 15.
[0020]
The back material 16 is made of, for example, a weather-resistant fluororesin sandwiching an aluminum foil so as not to transmit moisture.
[0021]
In the solar cell module, a translucent substrate 12, fillers 13, 15, a solar cell element 14, and a backing material 16 as shown in FIG. 1 are superimposed as shown in FIG. I do.
[0022]
FIG. 2 is a diagram showing a state in which two solar cell elements are connected in series using the connection tab according to the present invention. In FIG. 2, reference numerals 1 and 2 denote solar cell elements, reference numerals 3 and 4 denote light receiving surface side bus bar electrodes, and reference numeral 7 denotes a light receiving surface side finger electrode. Reference numerals 17 and 18 denote connection tabs according to the present invention.
[0023]
The attachment of the connection tabs 17 and 18 to the solar cell element 1 is performed in the same manner as described above. That is, the connection tabs 17 and 18 are arranged on the light receiving surface side bus bar electrodes 3 and 4 of the solar cell element 1 so as not to hide the light receiving surface. Further, the connection tabs 17 and 18 are pressed against the light receiving surface side bus bar electrodes 3 and 4 with a soldering iron, so that the solder on the surface portions of the connection tabs 17 and 18 and the light receiving surface side bus bar electrodes 17 and 18 is melted. The connection tabs 17 and 18 are connected to the light-receiving-surface-side busbar electrodes 3 and 4 of the solar cell elements 1 and 2.
[0024]
FIG. 3 is a diagram showing one embodiment of the connection tab of the present invention. In FIG. 3, reference numeral 19 denotes a portion of the connection tab on an electrode such as a busbar electrode portion on the light receiving surface side or the back surface side of the solar cell element, and reference numeral 20 denotes a portion on the electrode such as the busbar portion when the solar cell elements are connected to each other. There is no part.
[0025]
As shown in FIG. 3, only a portion 20 of the connection tab 17 that is not on the electrode such as a bus bar is wider than a portion 19 on the electrode such as the bus bar electrode on the light receiving surface side and the back side of the solar cell element. Keep it. As a result, the electric resistance of the portion 20 not on the electrode, such as a bus bar, and the portion 19 on the electrode become substantially the same, and the output of the solar cell module is not reduced by the influence of the portion 20 of the connection tab 19 not on the electrode. The width of the portion 20 not on the electrode may be determined in consideration of a current value generated by the solar cell element, a dimension between the solar cell elements, and the like.
[0026]
FIG. 4 is a diagram showing another embodiment of the connection tab of the present invention. In FIG. 4, reference numeral 21 denotes a portion on the bus bar electrode on the light receiving surface side, reference numeral 22 denotes a portion not on the electrode such as the bus bar portion, and reference numeral 23 denotes a portion on the back surface side of the electrode such as the bus bar.
[0027]
In the connection tab shown in FIG. 4, if the width of the portion 21 on the light-receiving side bus bar electrode is larger than the width of the light-receiving side bus bar, the connection tab protrudes to the light receiving surface, and the photocurrent of the solar cell element decreases. The width of the portion 21 on the busbar electrode on the light receiving surface side is set to be smaller than the width of the busbar on the light receiving surface side. Therefore, the width of the portion 21 on the busbar electrode on the light receiving surface side is the smallest.
[0028]
In addition, a portion 22 that is not on the electrode, such as a portion located between a plurality of solar cell elements when connected, is the widest in order to reduce electric resistance.
[0029]
Furthermore, in the portion 23 on the electrode such as the bus bar on the back surface side of the solar cell element of the connection tab 17, the width is wider than the width of the portion 23 on the bus bar electrode on the light receiving surface in order to increase the ease of connection work and the connection strength. Has become.
[0030]
Each of the connection tabs 17 shown in FIGS. 3 and 4 can be formed by punching a solder-coated copper foil with a punching die formed in a predetermined shape.
[0031]
FIG. 5 is a sectional view showing another embodiment of the connection tab of the present invention. In FIG. 5, reference numeral 24 denotes a portion of the connection tab on an electrode such as a light-receiving surface side or a back-side busbar electrode of the solar cell element, and 25 denotes a portion between the plurality of solar cell elements when the solar cell elements are connected to each other. It is a part that is not on the electrode, such as where it is located. Only this portion 25 is thickened to reduce the electric resistance. Accordingly, it becomes possible by soldering or further attaching a copper foil or the like with a conductive adhesive only to the portion 25 not on the electrode when the solar cell elements are connected to each other.
[0032]
Note that the present invention is not limited to the above-described embodiment. For example, the solar cell element is not limited to a crystalline solar cell such as a single crystal or polycrystalline silicon, and may be formed on a back surface of a light-transmitting substrate in a thin film solar cell or the like. The present invention can be applied to a solar cell module in which a plurality of solar cell elements are arranged and the plurality of solar cell elements are electrically connected by a connection tab.
[0033]
【The invention's effect】
As described above, according to the solar cell module according to the present invention, the width of the connection tab in a portion where the connection tab and the electrode are not connected is increased, and the thickness of this portion is increased, thereby increasing the thickness of the solar cell module. Can be reduced. As a result, the electric output can be improved even with solar cell modules of the same size.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a solar cell module of the present invention.
FIG. 2 is a diagram showing a state in which two solar cell elements are connected in series using a connection tab of the present invention.
FIG. 3 is a diagram showing one embodiment of a connection tab of the present invention.
FIG. 4 is a view showing another embodiment of the connection tab of the present invention.
FIG. 5 is a view showing still another embodiment of the connection tab of the present invention.
FIG. 6 is a cross-sectional view of a connection portion between two connected solar cell elements.
FIG. 7 is a diagram showing two solar cell elements connected using a conventional connection tab.
[Explanation of symbols]
1, 2: solar cell element, 3, 4: light-receiving surface side bus bar electrode, 5, 6: connection tab, 7: light-receiving surface side finger electrode, 8: P-type substrate, 9: N-type impurity diffusion layer, 10: high Concentration P-type impurity diffusion layer, 11: back side bus bar electrode, 12: translucent substrate, 13, 15: filler, 14: a plurality of solar cell elements connected by connection tabs, 16: back surface material, 17, 18: Connection tab according to the present invention, 19: Portion of the connection tab on the electrode, 20: Portion of the connection tab not on the electrode, 21: Portion of the connection tab on the light receiving surface side of the bus bar electrode, 22: Connection Portion of the tab not on the electrode, 23: portion on the back side electrode, 24: portion on the connection tab electrode, 25: portion of the connection tab not on the electrode

Claims (2)

In a solar cell module in which a plurality of solar cell elements having electrodes on the front and back surfaces are electrically connected by connection tabs and arranged on the back side of the light-transmitting substrate, a width of a connection tab between the electrodes of the plurality of solar cell elements is provided. Is wider than the width on the electrode. In a solar cell module in which a plurality of solar cell elements having electrodes on the front and back surfaces are electrically connected by connection tabs and arranged on the back surface side of the light-transmitting substrate, the thickness of the connection tab between the electrodes of the plurality of solar cell elements is Is thicker than the thickness on the electrode.

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