KR102344196B1 - Melting solder for photovoltaic module, electrode wire for photovoltaic module having the same, and photovoltaic module - Google Patents

Abstract

The present invention provides a molten solder for a solar module having a low melting point and high bonding strength. Molten solder for a solar module according to an embodiment of the present invention, 59.5% by weight to 60.0% by weight of tin (Sn); indium (In) in the range of 0.1% to 0.5% by weight; and the balance includes lead (Pb) and unavoidable impurities.

Description

Molten solder for photovoltaic module, electrode wire for photovoltaic module including same, and photovoltaic module

The technical idea of the present invention relates to a photovoltaic module, and more particularly, to a molten solder for a photovoltaic module, an electrode wire for a photovoltaic module, and a photovoltaic module.

Due to the depletion of chemical energy such as coal or oil and environmental pollution caused by the use of chemical energy, efforts are being made to develop alternative energy in recent years, and one of them is solar power generation using solar energy. Solar power generation is a series of technologies that convert solar energy such as sunlight or solar heat into electrical energy.

Briefly looking at the basic principle of photovoltaic power generation, when sunlight is irradiated to a solar cell composed of a PN junction semiconductor, charges and holes are generated by light energy, and electrons and holes move to form the N layer and An electromotive force is generated by the photovoltaic effect in which a current flows across the P layer, and the result of current flowing to an externally connected load is used. In order to convert infinite, pollution-free solar energy into electric energy, above all, it is required to develop a technology for a photovoltaic module for concentrating sunlight. In general, solar cells for photovoltaic power generation start from silicon or various compounds and can produce electricity when in the form of a solar cell. However, since a single cell does not provide sufficient output, each cell must be connected in series or parallel, and this connected state is called a solar module. As the photovoltaic industry increases, the demand for photovoltaic modules is rapidly increasing.

The configuration of the solar module is generally composed of a back sheet, a solar cell unit, a solar electrode wire, EVA, and glass. TPT (Tedlar/PET/Tedlar) type is widely used for the back sheet as the material under the module. Use the ones that contain less iron. Since the photovoltaic electrode wire is used as an electric current flowing wire, a material plated with tin and lead on a copper ribbon is mainly used. The photovoltaic electrode wire is a wire that is a passage for solar power, and is used to manufacture a photovoltaic module by attaching it to the photovoltaic unit.

The molten solder plated on the surface of the photovoltaic electrode wire requires a low melting point to minimize damage to the photovoltaic module due to thermal shock during high-temperature bonding, and high bonding strength to the semiconductor substrate.

Korean Patent No. 10-1245042

The technical problem to be achieved by the technical idea of the present invention is to provide a molten solder for a solar module having a low melting point and high bonding strength.

The technical problem to be achieved by the technical idea of the present invention is to provide an electrode wire for a photovoltaic module including the molten solder for the photovoltaic module.

The technical problem to be achieved by the technical idea of the present invention is to provide a photovoltaic module composed of an electrode wire for a photovoltaic module including the molten solder for the photovoltaic module.

However, these tasks are exemplary, and the technical spirit of the present invention is not limited thereto.

Molten solder for a solar module according to the technical idea of the present invention for achieving the above technical problem, 59.5% by weight to 60.0% by weight of tin (Sn); indium (In) in the range of 0.1% to 0.5% by weight; and the balance includes lead (Pb) and unavoidable impurities.

In some embodiments of the present invention, the molten solder for the solar module may have a melting point in the range of 181°C to 183°C.

In some embodiments of the present invention, the molten solder for the solar module may have a contact angle in the range of 9.3 degrees to 10.5 degrees.

In some embodiments of the present invention, the molten solder for a solar module may have a bonding force in the range of 2.80 N to 3.21 N.

Electrode wire for a solar module according to the technical idea of the present invention for achieving the above technical problem, a conductive core material; and a molten solder layer formed on the surface of the conductive core material, wherein the molten solder layer comprises: tin (Sn) in an amount of 59.5 wt% to 60.0 wt%; indium (In) in the range of 0.1% to 0.5% by weight; and the balance includes lead (Pb) and unavoidable impurities.

A photovoltaic module according to the technical idea of the present invention for achieving the above technical problem, a plurality of solar cell units; and an electrode wire for a solar module that electrically connects the solar cells, wherein the electrode wire for a solar module includes: a conductive core; and a molten solder layer formed on the surface of the conductive core material, wherein the molten solder layer comprises: tin (Sn) in an amount of 59.5 wt% to 60.0 wt%; indium (In) in the range of 0.1% to 0.5% by weight; and the balance includes lead (Pb) and unavoidable impurities.

The molten solder for a solar module according to the technical spirit of the present invention is formed of a tin-lead alloy containing indium in a range of 0.1 wt% to 0.5 wt%, thereby reducing the melting point and the contact angle, thereby increasing the bonding strength can do it Therefore, since the solar cell unit and the electrode wire can be electrically contacted at a low temperature, damage to the solar module due to thermal shock can be minimized.

The above-described effects of the present invention have been described by way of example, and the scope of the present invention is not limited by these effects.

1 is a graph showing the melting point of the molten solder for a solar module according to an embodiment of the present invention.
2 is a view of forming a contact angle and meniscus for molten solder for a solar module according to an embodiment of the present invention.
3 is a graph showing the bonding strength of molten solder for a solar module according to an embodiment of the present invention.
4 is a schematic diagram illustrating an electrode wire for a solar module including a molten solder for a solar module according to an embodiment of the present invention.
5 is a plan view illustrating a solar module according to an embodiment of the present invention.
6 is a cross-sectional view illustrating a solar module according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments of the present invention are provided to more completely explain the technical idea of the present invention to those of ordinary skill in the art, and the following examples may be modified in various other forms, The scope of the technical idea is not limited to the following examples. Rather, these embodiments are provided so as to more fully and complete the present disclosure, and to fully convey the technical spirit of the present invention to those skilled in the art. In this specification, the same reference numerals refer to the same elements throughout. Furthermore, various elements and regions in the drawings are schematically drawn. Accordingly, the technical spirit of the present invention is not limited by the relative size or spacing drawn in the accompanying drawings.

Molten solder for a solar module according to an embodiment of the present invention, 59.5% by weight to 60.0% by weight of tin (Sn); indium (In) in the range of 0.1% to 0.5% by weight; and the balance includes lead (Pb) and unavoidable impurities.

However, the above range is exemplary and the technical spirit of the present invention is not limited thereto. For example, molten solder containing indium in the range of 0.1% to 0.5% by weight, 5% by weight to 98% by weight of tin and the balance contains lead and unavoidable impurities, etc. included in thought.

The unavoidable impurities may include various elements, for example, silver (Ag), antimony (Sb), copper (Cu), bismuth (Bi), zinc (Zn), iron (Fe), aluminum (Al), Arsenic (As), cadmium (Cd), and the like may be included.

Table 1 is a table showing the chemical composition and characteristics of the molten solder for a solar module according to an embodiment of the present invention.

Classification Furtherance characteristic Remark lead indium melting point
(℃) contact angle
(Degree) bonding force
(N) bonding force
rate of rise comparative example 60 40 0 183.1 10.5 2.74 0 Example 1 60 39.9 0.1 182.8 10.5 2.80 2.2% Example 2 60 39.8 0.2 182.5 10.1 2.89 5.5% Example 3 60 39.7 0.3 182.2 9.7 3.01 9.9% Example 4 60 39.6 0.4 181.8 9.3 3.09 12.8% Example 5 60 39.5 0.5 181.5 9.3 3.21 17.2%

1 is a graph showing the melting point of the molten solder for a solar module according to an embodiment of the present invention.

Referring to Table 1 and FIG. 1 , the Examples including indium had a lower melting point compared to Comparative Examples not including indium. In addition, the melting point of the molten solder for solar modules decreased as the indium content increased. Accordingly, the molten solder for the solar module may have a melting point in the range of 181°C to 183°C. As the melting point is lowered, the fluidity of the solder is increased to improve the wettability, and accordingly, the solderability and bonding strength can be improved under the same soldering conditions.

Contact angle measurement was performed as follows. After the molten solder corresponding to the Comparative Examples and Examples was rolled into a plate material having a thickness of 0.2 mm, a disk having a diameter of 3 mm and a thickness of 0.2 mm was formed by drilling with a punch having a diameter of 3 mm. After the rosin-based flux was applied on the 0.5 mm thick copper plate subjected to surface polishing and acetone cleaning, the disk-shaped molten solder was placed. The copper plate on which the disk-shaped molten solder was disposed was placed on a hot plate at 240 DEG C, and heated and maintained for 30 seconds. Then, the hot plate was removed, and the copper plate on which the disk-shaped molten solder was disposed was air-cooled. After cooling, the cross-section of the copper plate on which the disk-shaped molten solder was disposed was observed under an optical microscope to measure the contact angle of the molten solder.

2 is a view of forming a contact angle and meniscus for molten solder for a solar module according to an embodiment of the present invention.

Referring to Table 1 and FIG. 2 , the examples including indium had a lower contact angle compared to the comparative examples not including indium. In addition, as the indium content increased, the contact angle of the molten solder for the solar module decreased. Accordingly, the molten solder for the solar module may have a contact angle in the range of 9.3 degrees to 10.5 degrees. The decrease in the contact angle means that the spreadability is remarkable, and it means that the width of the meniscus between the solar cell and the electrode wire increases. Accordingly, the soldered or bonded area is increased, and thus the bonding force is increased.

3 is a graph showing the bonding strength of molten solder for a solar module according to an embodiment of the present invention.

Referring to Table 1 and FIG. 3 , the examples including indium had high bonding strength compared to the comparative examples not including indium. In addition, as the indium content increased, the bonding strength of the molten solder for the solar module was increased. The molten solder for the solar module may have a bonding force in the range of 2.80 N to 3.21 N. Compared to the comparative example, the increase rate of bonding strength was up to 17.2%.

4 is a schematic diagram illustrating an electrode wire 10 for a solar module including a molten solder for a solar module according to an embodiment of the present invention.

Referring to FIG. 4 , the electrode wire 10 for a solar module includes a conductive core 2 and a molten solder layer 3 formed on the surface of the conductive core 2 .

The conductive core 2 may include a material having excellent conductivity and solderability, for example, a metal, for example, copper, silver, aluminum, palladium, or an alloy thereof. In addition, the conductive core 2 may include one type of material or may include two or more types of materials. For example, it may include a plurality of cladding layers each made of a different material.

The molten solder layer 3 may comprise molten solder as described above, for example, tin (Sn) in the range of 59.5 wt% to 60.0 wt%; indium (In) in the range of 0.1% to 0.5% by weight; and the balance includes lead (Pb) and unavoidable impurities. The molten solder layer 3 may have various thicknesses, for example in the range from 10 μm to 100 μm, and for example in the range from 20 μm to 40 μm.

The electrode wire 10 for a solar module may have various shapes, such as a circular cross section, a rectangle, and a polygon. The electrode wire 10 for a solar module may have a cross-sectional diameter in the range of, for example, 0.1 mm to 6.0 mm.

When soldering the electrode wire to the semiconductor substrate on which the solar cell is formed, the heating temperature needs to be strictly controlled to a low temperature near the melting point of the molten solder layer. The reason is that the thermal expansion coefficient of the metal material forming the conductive core of the electrode wire, for example, copper or aluminum, and the silicon forming the semiconductor substrate, for example, are different. In other words, the electrode wire needs to be soldered at as low a temperature as possible so that the thermal stress that causes cracks in the expensive semiconductor substrate is as small as possible. Therefore, the lower the melting point of the molten solder layer, the better.

5 is a plan view illustrating a solar module 30 according to an embodiment of the present invention.

Referring to FIG. 5 , the photovoltaic module 30 includes a plurality of solar cell units 20 and an electrode wire 10 for a photovoltaic module electrically connecting the solar cell units 20 . The configuration of the electrode wire 10 for a solar module is as described above. Also, although not shown, the electrode wire 10 for a solar module may be used in an interconnecter and a bus bar connecting the interconnector.

6 is a cross-sectional view showing a solar module 30 according to an embodiment of the present invention.

Referring to FIG. 6 , the solar module 30 includes a solar cell unit 20 including a semiconductor substrate formed on a silicon semiconductor having a PN junction, and a first electrode 90a and a second electrode 90b formed on the semiconductor substrate. ), and an electrode wire 10 for a solar module. In addition, the solar module 30 further includes a sealing unit 40 , a cover film unit 50 , a sealing unit 60 , and a cover glass unit 70 . One lower surface of the electrode wire 10 for a photovoltaic module is in electrical contact with the surface of the first electrode 90a, and the other upper surface of the electrode wire 10 for a photovoltaic module is in electrical contact with the second electrode 90b. do. This electrical contact is implemented by the above-described molten solder layer 3 of the electrode wire 10 for a solar module. Accordingly, the plurality of solar cell units 20 may be connected in series to generate a desired electromotive force.

The technical spirit of the present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is the technical spirit of the present invention that various substitutions, modifications and changes are possible without departing from the technical spirit of the present invention. It will be apparent to those of ordinary skill in the art to which this belongs.

10: electrode wire for solar module
2: Conductive core material
3: molten solder layer
20: solar cell unit
30: solar module
40: suture
50: cover film unit
60: seal
70: cover glass portion
90a: first electrode
90b: a second electrode;

Claims (6)

tin (Sn) in the range of 59.5% to 60.0% by weight;
lead (Pb) in the range of 39.5% to 39.9% by weight;
indium (In) in the range of 0.1% to 0.5% by weight; and
A molten solder for solar modules containing unavoidable impurities, comprising:
having a melting point of 181.5°C to 182.8°C, a contact angle of 9.3° to 10.5°, and a bonding force of 2.80N to 3.21N,
Molten solder for solar modules. delete delete delete conductive core; and
Including; a molten solder layer formed on the surface of the conductive core material;
The molten solder layer may include 59.5 wt% to 60.0 wt% of tin (Sn); lead (Pb) in the range of 39.5% to 39.9% by weight; indium (In) in the range of 0.1% to 0.5% by weight; And as an electrode wire for a solar module, including unavoidable impurities,
the molten solder layer has a melting point of 181.5°C to 182.8°C, a contact angle of 9.3° to 10.5°, and a bonding force of 2.80N to 3.21N;
Electrode wire for solar modules. a plurality of solar cell units; and
and an electrode wire for a solar module that electrically connects the solar cells.
The electrode wire for the solar module may include a conductive core; and a molten solder layer formed on the surface of the conductive core.
The molten solder layer may include 59.5 wt% to 60.0 wt% of tin (Sn); lead (Pb) in the range of 39.5% to 39.9% by weight; indium (In) in the range of 0.1% to 0.5% by weight; and unavoidable impurities, as a solar module,
the molten solder layer has a melting point of 181.5°C to 182.8°C, a contact angle of 9.3° to 10.5°, and a bonding force of 2.80N to 3.21N;
Solar modules.

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