TWI705659B - Manufacturing method of solar cell module - Google Patents

Abstract

A method for manufacturing a solar cell module includes the following steps: a flux coating step, which is to coat the flux on the first side connecting electrode provided on the first side of the solar cell unit and on the second side The second surface is connected to the electrode; and the lamination step, which is to laminate the first sheet of wire, the second surface of the solar cell unit, and the second sheet of wire on the heating plate. It also includes the following steps: a pressing step, which presses the second sheet wire from above; a pre-heating step, which uses a heating plate to preheat the solar cell unit to a predetermined pre-heating temperature; and a heating step, which uses a lamp heater The infrared rays from the second surface heat the solar cell to a predetermined heating temperature.

Description

Manufacturing method of solar cell module

The present invention relates to a method for manufacturing a solar cell module that uses tab wires to connect solar cell units.

Previously, when soldering solar battery cells and chip wires, solder plating (solder plating) has a copper foil chip wire with a cross-sectional structure of about 0.2mm×1.0mm, the solder system usually uses SnPb solder. However, because lead (PB) is a metal that is harmful to the human body, it is now subject to regulation.

Lead-based solder was used in the electronic substrates or wiring of electrical products mounted in refrigerators, air conditioners, microwave ovens, washing machines, and ventilators. But since 2006, in accordance with the Hazardous Substances Use Restriction Directive (DIRECTIVE 2002/95/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 27 January 2003 on the restriction of the use of certain hazardous substances in electrical and electronic equipment) Equipment Hazardous Substances Restriction Directive); RoHS Directive) specifications of lead-free solders are used in addition to special electrical products. For example, when ordinary landfill treatment is used as waste treatment, this directive is set as the possibility that harmful lead components will be eluted from the solder of waste products due to rainwater, etc. and cause groundwater pollution.

On the other hand, as with special electrical devices, it is difficult to determine the moduleization of solar cells by using lead-free solder to solder the wire, so solar cell modules are also excluded from the RoHS directive. Products, most of the solar cell module products currently use SnPb solder. One of the reasons why it is difficult to use lead-free solder to solder the chip wires and modularization of solar cells is because the melting point of lead-free solder is higher than that of lead-free solder. Above ℃, the specifications of the welding equipment must be in response to high temperature. When discussing the RoHS directive, the solar cell industry is in the dawn from the perspective of popularization. The popularization of solar cell modules, that is, the mass production of solar cell modules, has become a priority of various countries and is positioned outside the RoHS directive. Products.

Under this situation, the popularization of solar cell modules has progressed substantially since 2006. In Japan, the annual power generation capacity was about 250MW in 2008, but it has become a scale of more than 5000MW since 2012. According to the policy for the promotion of the recycling of photovoltaic power generation equipment, the March 2008 edition, the trial calculation records "Assuming that the life of the photovoltaic power generation equipment is 25 years, the emissions of the photovoltaic power generation equipment will be one in 2020. 3,000 tons per year, 30,000 tons in 2030". On the other hand, with regard to the RoHS directive, Europe also believes that from around 2021 the application exclusions should be reviewed, and even solar cell modules have gradually become lead-free.

As a technique commonly used for welding solar battery cells and tab wires, Patent Document 1 discloses that the solar battery cells provided with tab leads can be heated from a lamp heater while preheating using a heating plate. Infrared rays are irradiated to further heat the solder with the lead wire to the melting temperature of the solder, and then the lamp heater is turned off to cool the solder to perform soldering.

When the soldering method described in Patent Document 1 is applied to soldering using Sn-37Pb-based solder, the melting point of Sn-37Pb-based solder is 183°C, so when the peak temperature of the temperature graph is set to 190°C, the system can be used. welding.

On the other hand, in the lead-free solder, the National Research and Development Corporation New Energy and Industrial Technology Development Organization (New Energy and Industrial Technology Development Organization (NEDO): NEDO) recommends that it be formed as Sn-3.0Ag -0.5Cu series lead-free solder is used as a solder material. Because the melting point of Sn-3.0Ag-0.5Cu-based solder reaches a high temperature from 216°C to 221°C, it is difficult to directly transfer the original soldering equipment. Therefore, considering the conditions of low-temperature processing and wettability during soldering, the Sn-3.0Ag-0.5Cu-based solder further adds bismuth (Bi) or nickel (Ni) to the research and practical application of the system. . In the above-mentioned electrical products, lead-free can be achieved by using solder added with Bi or Ni.

Prior art literature

Patent literature

[Patent Document 1] Japanese Patent No. 4986401

Non-patent literature

[Non-Patent Document 1] General Incorporated Association of Electronics and Information Technology Industries, "Committed to the Reliability of Lead-Free Solder Joints", JEITA Review (General Incorporated Association of Electronics and Information Technology Industries Association Review) April 2008, p.16-20.

However, because the solar cell module is installed outdoors, the specifications must be determined in consideration of the humidity and temperature cycle of the outdoor environment. When considering the high temperature and high humidity conditions at 85°C, about 85%, and the rupture life during temperature cycling, according to the finishing disclosed in Non-Patent Document 1, compared to the addition of Bi or Ni contained in Sn-3.0Ag-0.5Cu SnPb solder with finished specifications and lead specifications still has no better composition than Sn-3.0Ag-0.5Cu.

From the above point of view, it is expected that high-quality soldering of solar cells and chip wires can be achieved by using lead-free solder with a higher processing temperature than SnPb-based solders under the conditions that can utilize existing equipment for soldering. .

The present invention is made in view of the above, and its object is to use the original equipment and use lead-free solder to achieve a high-quality solar cell module manufacturing method for soldering the solar cell and the wire.

In order to solve the above-mentioned problems and achieve the objective, the manufacturing method of the solar cell module of the present invention includes the following steps: a flux coating step, which is to apply flux to the first surface connecting electrode provided on the solar cell And a second side connection electrode, wherein the solar cell has a first side and a second side opposite to the first side, the first side connection electrode is provided on the first side, and the second side connection electrode is provided on the second side; and The stacking step is to laminate the first sheet wire whose surface is coated with lead-free solder, the solar cell unit whose second surface is upward, and the second sheet wire whose surface is coated with lead-free solder, on the heating plate. Moreover, the method of manufacturing a solar cell module is characterized by including the following steps: a pressing step, which uses a pressing device to press the second sheet wire from above; a preheating step, which uses a heating plate to preheat the solar cell unit to a predetermined The pre-heating temperature; and the heating step, which uses the infrared light of the lamp heater to heat the solar cell unit to a predetermined heating temperature from the second surface side.

The manufacturing method of the solar cell module of the present invention achieves the effect of using the original equipment and using lead-free solder to achieve high-quality soldering of solar cell units and chip wires.

1‧‧‧Film line

1a‧‧‧Copper foil

1b‧‧‧Solder plating

2‧‧‧Winding tube

3‧‧‧Pleated thread removal device

4‧‧‧wheel

5‧‧‧Slice line cutting device

6‧‧‧Film line transfer device

11‧‧‧Solar battery unit

11a‧‧‧Right side solar cell unit

11b‧‧‧Left solar battery unit

12‧‧‧Light-receiving surface electrode

13‧‧‧Light-receiving surface grid electrode

14‧‧‧Silver bus electrode on light-receiving surface

15‧‧‧Back electrode

16‧‧‧Back aluminum electrode

17‧‧‧Back silver bus electrode

17a‧‧‧Ag

21‧‧‧Flux coating device

22‧‧‧Flux

23, 23a, 23b, 23c, 23d‧‧‧heating plate

24‧‧‧Slice line groove

25‧‧‧Pressing device

26‧‧‧pin

27‧‧‧Axis

28‧‧‧Light heater

29‧‧‧Infrared

31‧‧‧Semiconductor substrate

32‧‧‧Gap

Md‧‧‧ditch depth

Mw‧‧‧Ditch width

Tw‧‧‧ film width

Td‧‧‧sheet thickness

S10‧‧‧ Film line preparation steps

S20‧‧‧Flux coating step

S30‧‧‧First piece line configuration steps

S40‧‧‧Solar battery unit configuration steps

S50‧‧‧Second piece line configuration steps

S60‧‧‧Pressing steps

S70‧‧‧Pre-heating step

S80‧‧‧Heating step

Fig. 1 is a flowchart showing the procedure of the manufacturing method of the solar cell module in the first embodiment of the present invention.

Fig. 2 is a process diagram for explaining an example of the manufacturing method of the solar cell module in the first embodiment of the present invention, and shows a diagram of the chip wire pulled out from the bobbin in the step of preparing the chip wire.

Figure 3 is a process diagram for explaining an example of the manufacturing method of the solar cell module in the first embodiment of the present invention, showing the step of removing the "wrinkle line" of the sheet line in the step of preparing the sheet line .

Figure 4 is a process diagram for explaining an example of the method of manufacturing a solar cell module according to the first embodiment of the present invention. It shows that in the step of preparing the wire, the "crease" will be removed by the wire cutting device. A schematic diagram of the state where the subsequent film line is cut and held in the film line transfer device.

Fig. 5 is a schematic perspective view of the solar battery cell used in the manufacturing method of the solar battery module according to the first embodiment of the present invention viewed from the light-receiving surface side.

Fig. 6 is a schematic perspective view of the solar cell unit used in the manufacturing method of the solar cell module according to Embodiment 1 of the present invention viewed from the back side facing the light-receiving surface.

Figure 7 is a process diagram for explaining an example of the manufacturing method of the solar cell module in the first embodiment of the present invention, showing the silver bus bar electrode on the light-receiving surface side of the solar cell by applying flux to the light-receiving surface Diagram of the steps.

Figure 8 is a process diagram for explaining an example of the manufacturing method of the solar cell module in the first embodiment of the present invention, showing a state after applying flux to the silver bus electrode on the light-receiving surface of the solar cell Schematic perspective view.

Figure 9 is a process diagram for explaining an example of the manufacturing method of the solar cell module in the first embodiment of the present invention, showing a schematic diagram of the state after applying flux to the silver bus electrode on the back of the solar cell Stereograph.

Figure 10 is a process diagram for explaining an example of the manufacturing method of the solar cell module in the first embodiment of the present invention. The positional relationship of the constituent members when the adjacent solar cell units are connected to each other using a sheet wire Conceptual schematic exploded perspective view.

Fig. 11 is a process diagram for explaining an example of the manufacturing method of the solar cell module in the first embodiment of the present invention, and shows a perspective view of a state in which the sheet wires are arranged on the heating plate and pressed from above with a pressing device.

Fig. 12 is a process diagram for explaining an example of the manufacturing method of the solar cell module in the first embodiment of the present invention, and is a cross-sectional view showing the state in which the chip wires are arranged in the chip wire grooves.

Fig. 13 is a perspective view showing a sheet line groove formed on the upper surface of the heating plate used in the solar cell module manufacturing method of Embodiment 1 of the present invention.

Fig. 14 is a process diagram for explaining an example of the manufacturing method of the solar cell module in the first embodiment of the present invention, and is a perspective view showing a state in which solar cells are arranged on the heating plate.

Fig. 15 is a process diagram for explaining an example of the manufacturing method of the solar cell module in the first embodiment of the present invention, and is a perspective view showing a state in which the wires are arranged on the solar cell unit.

Fig. 16 is a process diagram for explaining an example of the manufacturing method of the solar cell module in the first embodiment of the present invention, and is a perspective view showing a state in which the sheet wire arranged on the solar cell unit is pressed from above using a pressing device.

FIG. 17 is a process diagram for explaining an example of the manufacturing method of the solar cell module in the first embodiment of the present invention, and is a perspective view showing the implementation state of the heating step.

Fig. 18 is a perspective view showing an example of a solar cell module manufactured by the method of manufacturing a solar cell module according to Embodiment 1 of the present invention.

Fig. 19 is a diagram showing the conditions of the temperature curve of the solar battery cell versus time when the sheet wire is welded to the solar battery cell in the solar battery module manufacturing method of the first embodiment of the present invention.

Fig. 20 is a schematic perspective view showing an example of the structure of a lamp heater used in the method of manufacturing a solar cell module according to Embodiment 1 of the present invention.

Figure 21 is a graph showing the Ag composition ratio of the solder used for soldering the tab wire and the peel strength of the tab wire to the back silver bus electrode of the solar cell using the solar cell module manufacturing method of Embodiment 1 of the present invention Characteristic diagram of relationship.

Fig. 22 is a schematic perspective view showing the observation area of the cross-sectional image of the solar battery cell after the sheet wire is welded using the method for manufacturing the solar battery module of the first embodiment of the present invention.

Figure 23 is a diagram showing the solar battery cell when the solder plated with Sn-0.3Ag-0.7Cu wire is soldered to the back silver bus electrode according to the method for manufacturing the solar cell module in the first embodiment of the present invention Profile photography.

Figure 24 is a schematic diagram showing Figure 23.

Figure 25 shows the cross-section of the solar battery cell when the solder plated with Sn-3.0Ag-0.5Cu is soldered to the back side silver bus-bar electrode in the method of manufacturing the solar cell module of the first embodiment of the present invention Take pictures.

Figure 26 is a schematic diagram showing Figure 25.

Hereinafter, the manufacturing method of the solar cell module in the embodiment of the present invention will be described in detail based on the drawings. In addition, the present invention is not limited by this embodiment. In addition, in the drawings shown below, for easy understanding, the scale of each member may be different from the actual one. The same applies between the various schemes. In addition, for easy understanding, hatching may be added to the plan view or the three-dimensional view.

Implementation mode 1.

Fig. 1 is a flowchart of the procedure of the manufacturing method of the solar cell module in Embodiment 1 of the present invention. In the manufacturing method of the solar cell module of the first embodiment of the present invention, the main steps include a flux coating step, a lamination step, a pressing step, a preheating step, and a heating step. In addition, the lamination step includes a first sheet wire arranging step, a solar battery cell arranging step, and a second sheet wire arranging step. Hereinafter, the manufacturing method of the solar cell module in the first embodiment will be described in accordance with the process sequence.

(Preparation steps for film line)

First, before the main steps of the manufacturing method of the solar cell module of this embodiment, the sheet line preparation step of preparing the sheet line 1 is carried out in stage S10. Figure 2 is a process diagram for explaining an example of the manufacturing method of the solar cell module in the first embodiment of the present invention, showing the wire drawn from the bobbin 2 in the step of preparing the wire 1 1 picture. Figure 3 is a process diagram for explaining an example of the manufacturing method of the solar cell module in the first embodiment of the present invention, showing that the "crease line" of the sheet line 1 is removed during the step of preparing the sheet line 1 Diagram of steps. Figure 4 is a process diagram for explaining an example of the manufacturing method of the solar cell module in the first embodiment of the present invention. It shows that the wire cutting device 5 is used to remove the wire during the step of preparing the wire 1 A schematic diagram of the state where the sheet thread 1 after the crease line is cut and held in the sheet thread transfer device 6.

As shown in FIG. 2, in the form 1 of this form, the sheet wire 1 is supplied from the bobbin 2. The sheet wire 1 wound around the bobbin 2 is bent in a manner to maintain the shape when wound around the bobbin 2 and has a circular "pleat wire" with the same diameter as the bobbin 2. When the piece thread 1 is pulled out from the bobbin 2 and used as it is, the "wrinkle thread" of the piece thread 1 hinders various actions in the subsequent steps. Therefore, the "crease line" of the sheet line 1 must be removed.

Therefore, as shown in FIG. 3, the sheet thread 1 supplied from the bobbin 2 passes through the crease thread removing device 3 to remove the "crease thread". The crease removing device 3 is configured to alternately arrange a plurality of rollers 4 up and down in the conveying direction of the sheet thread 1 to remove the "wrinkle thread" of the sheet thread 1. The thread 1 pulled out from the crease thread removing device 3 is as shown in FIG. 3, and is cut to a desired length by the thread cutting device 5 in the subsequent process. The cut sheet thread 1 is sucked and held by the sheet thread transfer device 6 arranged adjacent to the sheet thread cutting device 5 as shown in Fig. 4. The sheet wire transfer device 6 arranges the held sheet wire 1 in a predetermined position of the solar cell unit or the heating plate 23 described later.

(Flux coating step)

After the chip wire preparation step, in step S20, a flux coating step of applying flux to the bus bar electrodes on the front and back of the solar cell 11 is implemented. Fig. 5 is a schematic perspective view of the solar battery cell 11 used in the manufacturing method of the solar battery module according to the first embodiment of the present invention viewed from the light-receiving surface side. Fig. 6 is a schematic perspective view of the solar battery cell 11 used in the manufacturing method of the solar battery module according to Embodiment 1 of the present invention, as viewed from the back side facing the light-receiving surface.

The solar cell 11 is a normal bulk solar cell using a crystalline silicon substrate. In addition, the solar cell 11 is not limited to the bulk solar cell using a crystalline silicon substrate, and various bulk solar cells can be used.

The detailed illustration is omitted, and the solar cell 11 has an n-type impurity diffusion layer formed on the light-receiving surface side of a p-type single crystal silicon substrate having an external dimension of approximately 156 mm square to form a pn junction. In addition, an anti-reflection film may be formed on the n-type impurity diffusion layer. On the light-receiving surface side of the solar cell 11, as a comb-shaped light-receiving surface side electrode 12 that penetrates the anti-reflection film and connects the n-type impurity diffusion layer, the light-receiving surface grid electrode 13 and the light-receiving surface grid electrode are provided 13 The light-receiving surface silver bus electrode 14 electrically connected.

The light-receiving surface grid electrode 13 is mainly composed of silver (Ag) and has a width of less than 100 μm. The number of counts ranging from 80 to 150 is arranged at equal intervals on the entire surface of the n-type impurity diffusion layer. The light-receiving silver busbar electrode 14 is made of silver (Ag) as the main body, and the width is from 1mm to about 2mm. The number of counts ranging from 3 to 5 is at equal intervals in the direction orthogonal to the light-receiving grid electrode 13 It is arranged on the n-type impurity diffusion layer. In the first embodiment, the number of silver bus bar electrodes 14 on the light-receiving surface is four. In addition, in the following drawings, for ease of understanding, the light-receiving surface grid electrode 13 may be omitted.

On the back side of the solar cell 11, as the back side electrode 15, a back aluminum electrode 16 and a back silver bus bar electrode 17 electrically connected to the back aluminum electrode 16 are provided. The back aluminum electrode 16 is mainly composed of aluminum (Al) and is arranged on the substantially entire surface of the back surface of the p-type single crystal silicon substrate. The back silver bus bar electrode 17 is mainly made of silver (Ag) and is arranged in a dot shape in a region corresponding to the light-receiving surface silver bus bar electrode 14 on the light-receiving surface side of the solar cell 11.

Therefore, as shown in Figs. 5 and 6, on the first surface (rear surface) and the second surface (light-receiving surface) of the solar cell 11, busbar electrodes, which are connection electrodes for welding the chip wires 1, are formed. That is, in the solar battery cell 11, the second surface connecting electrode for welding the chip wire 1 that is the light-receiving silver bus bar electrode 14 is formed on the light-receiving surface side, and the second surface for welding the chip wire 1 is formed on the back side. The one-side connection electrode is the back silver bus bar electrode 17. On both the light-receiving surface side and the back surface side of the solar cell 11, the area of the electrode portion is set to be less than 10% of the area of the p-type single crystal silicon substrate. At this time, in the solar battery cell 11, the upper surface is the negative side, and the lower surface is the positive side.

Figure 7 is a process diagram for explaining an example of the manufacturing method of the solar cell module in the first embodiment of the present invention, showing the silver bus bar on the light-receiving surface side of the solar cell 11 where flux is applied Diagram of the steps of the electrode 14.

In order to solder the chip wire 1 to the connecting electrode of the solar cell 11, as shown in Figure 7, the flux 22 is applied from the flux coating device 21 for coating the flux 22 on the silver bus bar electrode on the light-receiving surface 14 on. In addition, in Figure 7, it is shown that the flux 22 is applied to the silver bus electrode 14 on the light-receiving surface of the solar battery cell 11. On the silver bus electrode 17 on the back of the solar battery cell 11, it is also on the side of the light-receiving surface. Similarly, the flux 22 can be applied from the flux application device 21.

Figure 8 is a process diagram for explaining an example of the manufacturing method of the solar cell module in the first embodiment of the present invention, showing that the flux 22 is applied to the silver bus electrode 14 of the light-receiving surface of the solar cell 11 Schematic perspective view of the state. Figure 9 is a process diagram for explaining an example of the manufacturing method of the solar cell module in the first embodiment of the present invention, showing the process after the flux 22 is applied to the silver bus electrode 17 on the back of the solar cell 11 Schematic perspective view of the state.

As described above, the solar cell 11 coated with the flux 22 on the light-receiving surface side and the back surface side is transferred to the heating plate 23 by a solar cell transfer device not shown.

(Layering step)

After the flux coating step, a laminating step of laminating the solar battery cell 11 and the sheet wire on the heating plate 23 is implemented. In the lamination step, the first sheet wire arranging step, the solar battery cell arranging step, and the second sheet wire arranging step are implemented. Figure 10 is a process diagram for explaining an example of the manufacturing method of the solar cell module in the first embodiment of the present invention. The position of the constituent members when the adjacent solar cell units 11 are connected to each other using the sheet wire 1 A conceptual schematic exploded perspective view of the relationship.

In Fig. 10, when one end side of the patch cord 1 is placed on the upper side of the right solar cell 11a placed on the right side, that is, the light-receiving surface side, the other end side of the patch cord 1 is placed adjacent to the right solar cell The lower side of the left side solar cell 11b on the left side of the unit 11a, that is, the back side. In addition, in Fig. 10, only two solar battery cells 11 are shown, but in reality, more solar battery cells 11 are arranged side by side. Furthermore, in each solar battery cell 11, the sheet wire 1 extending from the left side is arranged above the solar battery cell 11, and the sheet wire 1 extending from the right side is arranged below the solar battery cell 11. In addition, in the following steps from the first sheet line arrangement step in the following stage S30 to the pressing step in the stage S60, for ease of understanding, only the lamination step in one heating plate 23 will be described.

The sheet line 1 is a sheet line preparation step in step S10, and is cut to a length ranging from the light-receiving surface side of the two adjacent solar battery cells 11 to the back surface side. In addition, the sheet wire 1 is bent into a crank shape so that it can be arranged from the light-receiving surface side of the two adjacent solar battery cells 11 to the back side.

(Steps to configure the first piece of wire)

Figure 11 is a process diagram for explaining an example of the manufacturing method of the solar cell module in the first embodiment of the present invention, showing a state in which the sheet wire 1 is arranged on the heating plate 23 and pressed from above by the pressing device 25 Stereograph. Fig. 12 is a process diagram for explaining an example of the manufacturing method of the solar cell module in the first embodiment of the present invention, and is a cross-sectional view showing the state in which the chip wire 1 is arranged in the chip wire groove 24. Fig. 13 is a perspective view showing the sheet line groove 24 formed on the upper surface of the heating plate 23 used in the solar cell module manufacturing method of the first embodiment of the present invention.

In the first piece line arrangement step of stage S30, as shown in Figures 11 and 12, the four pieces of the first piece line 1 are arranged on the left side using the piece line transfer device 6 not shown On the heating plate 23. One heating plate 23 is prepared individually for one solar battery cell 11. Thereby, by increasing the number of heating plates 23, it is possible to easily realize the welding of the sheet wire 1 to the required number of solar cells 11. As shown in FIGS. 12 and 13, on the upper surface of the heating plate 23, the sheet wire 1 is arranged in the sheet wire groove 24 provided at the position corresponding to the connection electrode on the first surface of the solar battery cell 11.

As shown in FIG. 12, the chip wire 1 has a structure in which the surface of the core wire, that is, the copper foil 1a, is coated with a solder plating layer 1b of lead-free solder. In the first embodiment, Sn-3.0Ag-0.5Cu-based solder is used for lead-free solder. When the width of the sheet line 1 is set to the sheet width Tw, the thickness of the sheet line 1 is set to the sheet thickness Td, the groove width of the sheet line groove 24 is set to the groove width Mw, and the groove depth of the sheet line groove 24 is set to Md , The film line groove 24 is at the same time that the film line 1 is accommodated, in order to make the upper surface of the film line 1 protrude from the upper surface of the heating plate 23, it is required to satisfy "sheet thickness Td≒ groove depth Md, sheet thickness Td> groove depth Md, sheet width Tw≒The condition of groove width Mw, sheet width Tw<groove width Mw".

Furthermore, the sheet wire 1 arranged in the sheet wire groove 24 is pressed from above by using the pressing device 25 as shown in FIG. 11. Thereby, the sheet wire 1 is surely pressed in and is in a state of being closely adhered to the bottom of the sheet wire groove 24. The pressing device 25 is provided with a plurality of pins 26 for pressing the sheet wire 1 and the solar cell unit 11; and a driving means not shown that rotates the plurality of pins 26 with the shaft 27 as the center. The driving means rotates the plurality of pins 26 with the shaft 27 as the center, and displaces them on the heating plate 23 at the pressing position of the photo line 1 and the retreat position from the heating plate 23.

11 and 12 are not shown, the bottom of the sheet line groove 24 is formed at equal intervals in the longitudinal direction of the sheet line groove 24 consisting of a plurality of suction holes formed by the suction part, the suction part is connected To the suction device. In addition, the sheet wire 1 accommodated in the sheet wire groove 24 is in a state of being adsorbed by the suction portion to the heating plate 23 and fixed. Moreover, in the state where the sheet wire 1 is sucked on the heating plate 23, the pressing device 25 temporarily returns to the standby position. That is, the pressing device 25 is temporarily released.

(Solar cell configuration steps)

FIG. 14 is a process diagram for explaining an example of the manufacturing method of the solar cell module in Embodiment 1 of the present invention, and is a perspective view showing a state in which the solar cell unit 11 is arranged on the heating plate 23. The solar cell arrangement step in stage S40 is as shown in Fig. 14, the first side, that is, the back side, is set to face down, and the second side, that is, the light-receiving side, is set to face upwards. It is arranged on the heating plate 23, that is, on the four-piece line 1 arranged on the heating plate 23 using a conveying device not shown. The solar battery cell 11 is arranged on the heating plate 23 so that the position of the first surface connection electrode, that is, the back silver bus bar electrode 17 is aligned with the position of the sheet line 1 on the heating plate 23. The solar battery unit 11 is adsorbed by the heating plate 23 and becomes a fixed state by an unillustrated suction portion formed of suction holes formed on the upper surface of the heating plate 23.

(Second piece line configuration steps)

FIG. 15 is a process diagram for explaining an example of the manufacturing method of the solar cell module in the first embodiment of the present invention, and is a perspective view showing a state in which the sheet wire 1 is arranged on the solar cell unit 11. In the second sheet wire arranging step of stage S50, as shown in FIG. 15, the four sheet wires 1 of the second sheet wire are arranged on the solar cell unit 11 using the sheet wire transfer device 6 not shown. On the upper surface of the solar battery cell 11, the tab wire 1 is arranged on the second surface connection electrode of the solar battery cell 11, that is, the light-receiving surface silver bus bar electrode 14.

(Press step)

Figure 16 is a process diagram for explaining an example of the manufacturing method of the solar cell module in the first embodiment of the present invention, showing a state in which the sheet wire 1 arranged on the solar cell unit 11 is pressed from above by the pressing device 25 The three-dimensional view.

In the pressing step of stage S60, as shown in FIG. 16, the pressing device 25 is used to press from above. In order to achieve proper welding, it is necessary to appropriately set the pressing force of the sheet wire 1 during welding. By setting the pressing force using the pressing device 25 from 1.0 N to 3.5 N per point, it is possible to form a solder fillet with high bonding reliability and a welding system with high bonding reliability. When the pressing force per one point is less than 1.0N, there are cases where the tab wire 1 and the connection electrode of the solar battery cell 11 cannot be properly adhered. When the pressing force per point is greater than 3.5N, due to the force of the pressing device 25, the thickness of the solder between the back silver bus bar electrode 17 and the chip wire 1 may change when the solder is melted.

By performing the first sheet line arrangement step of stage S30 to the pressing step of stage S60 on the plurality of heating plates 23 arranged in parallel, the plurality of heating plates 23 constitute the plurality of solar battery cells 11 before welding Solar cells are in series. At this time, although not shown, the sheet wire 1 protruding from the right side of the solar cell unit 11 at the right end of the solar cell string is set to extend several cm, that is, to be connected to the adjacent string by a connecting sheet. The status of the length amount. On the other hand, the solar cell unit 11 at the left end of the solar cell string is also the same. The piece line 1 protruding from the left is also set to extend several cm, which is the length used to connect to the adjacent string by the connecting piece. The state of quantity.

(Pre-heating step)

Next, in the pre-heating step of stage S70, the heating plate 23 is used to pre-heat the sheet wire 1 and the solar cell unit 11. The heating plate 23 is set to a predetermined pre-heating temperature so that the temperature of the sheet wire 1 and the solar battery unit 11 before welding becomes the pre-heating temperature that is frequently required. In the first embodiment, the preheating temperature of the heating plate 23 is set to 180±3°C, that is, from 177°C to 183°C. The pre-heating of the heating plate 23 is to reliably pre-heat the sheet wire 1 at a predetermined temperature, that is, 180±3° C., and the adjacent solar battery cells 11 connected by the sheet wire 1 are kept in the pre-heated state until the heating step is completed. The pre-heating can also be maintained until the heating step of all the solar cell units 11 in the solar cell string ends.

(Heating step)

FIG. 17 is a process diagram for explaining an example of the manufacturing method of the solar cell module in the first embodiment of the present invention, and is a perspective view showing the implementation state of the heating step. The heating step of stage S80 is to irradiate the infrared rays 29 from the lamp heater 28 while being placed on the heating plate 23 with the sheet wire 1 and the solar battery unit 11 heated to 180±3°C due to preheating. The temperature of the sheet wire 1 and the solar cell unit 11 is raised and lowered to a predetermined heating temperature in such a way that the sheet wire 1 and the solar cell unit 11 can obtain the required temperature profile. Thereby, the tab wire 1 can be welded to the second surface connection electrode of the solar cell 11, namely the light-receiving surface silver bus bar electrode 14 and the first surface connection electrode, namely the back silver bus bar electrode 17, and can connect the solar cell 11 and Piece line 1 is joined.

Fig. 17 shows a state where the heating plate 23 is arranged side by side, the heating plate 23a at the left end is not placed with the sheet wire 1 and the solar battery unit 11 and the pressing device 25 is in a standby state. The second heating plate 23b from the left end is in a state where the chip wire 1 is placed and the pressing device 25 is pressing the chip wire 1. The third heating plate 23c from the left end is in a state where the sheet wire 1 is placed on the solar battery unit 11, and is heated by irradiating infrared rays 29 from a lamp heater 28 provided on the upper portion of the heating plate 23. The heating plate 23d at the right end is in a state after the welding of the chip wire 1 has been completed after the heating step by the lamp heater 28 has been passed. The equipment shown in Figure 17 starts from the heating plate 23d on the right, and implements the above-mentioned first sheet wire placement step, solar cell placement step, second sheet wire placement step, pressing step, preheating step, and Heating step.

On the right side of the solar battery unit 11 placed on the heating plate 23 under the lamp heater 28, the solar battery unit 11 after the heating step has been completed and the welding of the sheet wire 1 is completed is held on the heating plate 23 State. In this state, all the heating plates 23 are maintained at the preheating temperature until the welding of the sheet wire 1 is completed and the number of solar battery cells 11 electrically connected in series becomes a predetermined number.

Although not shown, for example, when the number of serial connections required is 5 units, the lamp heater 28 is used to repeatedly irradiate the infrared ray 29 for heating 5 times. When the infrared ray 29 is irradiated, the heating plate 23 is set to the right. slide. The solar battery unit 11 after the series connection is completed using the sheet wire 1 is removed from the heating plate 23 to the right side, and the tandem system is in a state of being placed on a transfer platform. As a result, as shown in FIG. 18, for example, a series of five solar battery cells 11 connected in series by the wire 1 is formed. Fig. 18 is a perspective view showing an example of a solar cell module manufactured by the method of manufacturing a solar cell module according to Embodiment 1 of the present invention. Moreover, when the irradiation of the infrared rays 29 ends, the lamp heater 28 may be slid to the left. Moreover, the tandem can also be used directly as a solar cell module, and a connecting piece can also be used to electrically connect a plurality of tandems as a solar cell module.

Fig. 19 is a diagram showing the temperature graph conditions of the solar battery cell 11 versus time when the sheet wire 1 and the solar battery cell 11 are welded in the solar cell module manufacturing method of the first embodiment of the present invention. In the manufacturing method of the solar cell module of the first embodiment, the heating step is performed by irradiating the infrared rays 29 for 3.7 seconds from the preheating state of the sheet wire 1 and the solar cell 11 at 180°C to realize the heating step of the sheet wire 1 welding.

This graph shows the average value of the temperature measured by attaching a thermocouple to a 156mm square solar cell at twelve places on the side surface of the light-receiving surface during the heating step. In Figure 19, a temperature curve showing the average value of the upper limit temperature of the solar cell 11 that can be welded on the wire 1 is the average of the measured temperature during the upper limit setting and the lower limit temperature of the solar battery 11 that can be welded on the wire 1 The temperature graph of the value is the measured temperature when the lower limit is set.

From Fig. 19, when the sheet wire 1 and the solar battery cell 11 are irradiated with infrared rays 29 from a preheating state of 180°C for 3.7 seconds, the lower limit of the heating temperature of the solar battery cell 11 in the heating step becomes 248°C. While adding The upper limit of the heating temperature of the solar battery cell 11 in the heating step is 264°C. When the heating temperature of the solar cell 11 is higher than 264° C., the active power of the flux 22 is lost and the solder plating layer 1 b of the lead-free solder is sintered on the heating plate 23. The heating temperature of the solar battery cell 11 is less than 248°C, and the melting of the solder plating layer 1b of the lead-free solder becomes insufficient.

In addition, the heating time of the sheet wire 1 and the solar cell 11 from the preheating state at 180° C. can be set between 3.6 seconds and 3.8 seconds. When the output power of the lamp heater 28 is constant and the heating time is less than 3.6 seconds, the heating temperature does not reach 248°C and the lead-free solder system does not reach a molten state suitable for soldering. On the other hand, when the output of the lamp heater 28 is constant, and the heating time is longer than 3.8 seconds, the heating temperature becomes higher than 264°C. For example, the original function of the flux 22 is impaired due to the deactivation of the flux 22 and the production of lead-free solder is suppressed. Conditions such as the enlargement used to form the fillet make proper welding difficult.

In this temperature graph, after receiving the peak temperature of the solar battery cell 11, the solar battery cell 11 enters the cooling state and enters the preheating state again. During this period, a certain voltage is applied to the lamp heater 28 and the output power of the lamp heater 28 does not change. In order to achieve the above rapid heating, the lamp heater 28 may be formed in a form facing each back silver busbar electrode 17. Fig. 20 is a schematic perspective view showing an example of the structure of the lamp heater 28 used in the method of manufacturing the solar cell module according to the first embodiment of the present invention. The lamp heater 28 shown in Fig. 20 divides the lamp into four to match the number of the back silver busbar electrodes 17. Infrared rays 29 are also set to converge on the back silver busbar electrodes 17 from each lamp. The composition of irradiation. That is, the lamp heater 28 shown in Fig. 20 is used for each back silver bus bar electrode 17 and has a lamp and optical parts, wherein the optical parts are used to condense the infrared rays 29 irradiated from the lamp to individually illuminate the back Silver bus bar electrode 17.

In addition, in the first embodiment, after the heating step, the time for cooling the solar battery cell 11 from the heating temperature, that is, the peak temperature, to the pre-heating temperature is 7.0 seconds to 9.0 seconds. When the cooling time from the peak temperature to the pre-heating temperature is less than 7.0 seconds, because the rapid cooling rate of the solar battery unit 11 is too fast, the solar battery unit 11 may be cracked due to the rapid deformation of the solar battery unit 11. When the cooling time from the peak temperature to the pre-heating temperature is longer than 9.0 seconds, the rapid cooling rate is too slow, so cooling the solar cell 11 to the pre-heating temperature takes more time than expected and cannot be produced as expected. number. In addition, in the manufacturing method of the solar cell module of the first embodiment, as shown in Figure 19, the solar cell 11 in the pre-heated state is heated from 3.6 seconds to 3.8 seconds, and then from 7.0 seconds to 9.0 seconds. The temperature graph of the clock from the heating temperature to the pre-heating temperature is important. As long as the temperature graph can be realized, it does not matter how the pre-heating step and the heating step are realized.

In addition, the temperature profile of one solar battery cell 11 in a tandem arrangement is heated to 180°C from the stage when it is placed on the heating plate 23, and is reached after the setting of the above-mentioned chip line 1 and the heating of the lamp heater 28 The peak temperature is then reduced to a temperature profile of 180°C by turning off the lamp heater 28. After the temperature is lowered to 180°C, the solar battery cell 11 is kept at 180°C. In the first embodiment, among the tandem, the solar battery cell 11 at the right end is kept at 180°C for the longest time.

In the first embodiment, since the solar battery cells 11 are kept at 180°C from the state in which the solar battery cells 11 are placed on the heating plate 23 until they are formed in tandem, the solar battery cells 11 are not caused by excessive cooling. Conditions for cracks. When the soldering of the sheet wire 1 is rapidly heated from room temperature to a peak temperature of 250°C to about 260°C and then rapidly cooled, cracks may occur due to the rapid deformation of the solar cell 110. Under these conditions, There is almost no crack due to welding.

After the sheet wire 1 is welded, the warpage caused by the difference between the expansion coefficient of the copper foil 1a of the sheet wire 1 and the silicon of the solar cell 11 is caused. When it is cooled in one go, the warpage occurs at the same time when the temperature is lowered. The situation of cracks. However, in the first embodiment, when the tandem is manufactured by welding the chip wires 1, the holding temperature of the cooling stays at the preheating temperature of 180°C, so that the rapid cooling of the solar cell 11 can be prevented and the solar cell can be prevented. The unit 11 cracks when the temperature is lowered.

That is, when the pre-heating temperature is less than 177° C., the solar cell unit 11 may be deformed rapidly due to the rapid heating or rapid cooling in the heating step, which may cause cracks. In addition, when the preheating temperature is higher than 183°C compared to when the preheating temperature is 180°C, the time that the flux 22 is exposed to a higher temperature increases, so the activity of the flux 22 may decrease. Moreover, when the preheating temperature is further higher than 183° C. to some extent, the original function of the flux 22 is impaired due to the deactivation of the flux 22 and proper soldering becomes difficult.

The soldering of the above-mentioned sheet wire 1 can be processed at a speed of less than 6 seconds per sheet when converted into one solar battery cell 11. In order to realize this situation, the flux 22 must be selected from an appropriate material. In the first embodiment, the material described in Japanese Patent No. 3734361 is used for the flux 22. That is, in the first embodiment, the flux 22 is formed by using a solvent component and a solid component, and the solid component contains an ester compound of the acid component rosin, and more than one type of rosin resin acid or It is made of modified rosin, and the content of rosin having a conjugated diene structure is 20% by weight or less relative to the solid content. By using this kind of flux 22, it is possible to achieve a peak temperature of about 260°C in 3.7 seconds from the preheating state of the hot plate 23 at 180°C and maintain the temperature at 180°C after cooling down Curve graph for welding.

By applying the above-mentioned flux 22, after the soldering of the above-mentioned chip wire 1, even if it is cleaned without using alcohol or flux remover, it has excellent heat cycle resistance, high temperature and high humidity resistance, and shows excellent UV degradation. With high durability, it can manufacture solar cell modules with high long-term reliability.

The inventors of the present invention have conducted studies on the composition ratio of the preferable lead-free solder used in the manufacturing method of the above-mentioned solar cell module. The composition ratio of the solder is described in the report "Efforts to lead-free solder joint reliability" in JEITA Review of Non-Patent Document 1, and is determined by referring to this report. In the following, the content quoted from Non-Patent Document 1 is enclosed in parentheses. In Non-Patent Document 1, the solder composition is changed to 12 types of composition, and the solder life is summarized based on the "thermal cycle test and creep test". Evaluation is performed in the thermal cycle test system discussed in Non-Patent Document 1. "The conditions of -40°C for 30 minutes and 90°C for 30 minutes are changed to 1 cycle, and the cumulative failure rate is 1%. number".

Among the solders described in Non-Patent Document 1, the inventors focused on the composition of "Sn-3.0Ag-0.5Cu, Sn-0.7Cu, Sn-0.3Ag-0.7Cu, Sn-0.5Ag-0.7Cu, And Sn-1.0Ag-0.7Cu" five types of solder, the dependence of the "number of thermal cycles at cumulative failure rate of 1" on the composition ratio of Ag in the solder composition was studied and described in Non-Patent Document 1. As a result, as described in Non-Patent Document 1, Sn-3.0Ag-0.5Cu solder showed the highest number of cycles among the above five types of solder.

On the other hand, the inventors of the present invention are the above-mentioned five types of solders described in Non-Patent Document 1, and discussed the dependence of the composition ratio of Ag in the solder composition on the "solder life based on creep test". Non-Patent Document 1 Record. As a result, as described in Non-Patent Document 1, Sn-3.0Ag-0.5Cu solder is superior to solders of other specifications among the above-mentioned five types of solders and exhibits several times the lifetime. From this point of view, refer to Non-Patent Document 1 for the selection of lead-free solder materials.

According to the aforementioned JEITA Review report, it can be confirmed that Sn-3.0Ag-0.5Cu solder is excellent. Therefore, the inventors of the present invention have confirmed the problem of actually applying Sn-3.0Ag-0.5Cu solder to the solar cell module manufactured by welding the solar cell and the chip wire. From a cost point of view, to suppress the amount of Ag used in the chip wire, compare it with Sn-3.0Ag-0.5Cu solder, which is generally circulated as a solder specification, followed by a report in Non-Patent Document 1 showing higher bonding reliability The result is Sn-1.0Ag-0.7Cu solder, and the composition ratio of Ag is less Sn-0.3Ag-0.7Cu solder.

Use the chip wire manufactured by solder plating Sn-3.0Ag-0.5Cu solder, the chip wire manufactured by solder plating Sn-1.0Ag-0.7Cu solder, and Sn-0.3Ag-0.7Cu For the sheet wire manufactured by solder plating with solder, the sheet wire 1 was soldered to the back silver bus bar electrode 17 of the solar cell 11 according to the above-mentioned method, and the sheet wire 1 peel strength was evaluated. Figure 21 shows the Ag composition ratio of the solder used for soldering the tab wire 1 and the tab wire 1 to the back side silver bus bar electrode 17 of the solar cell 11 using the solar cell module manufacturing method of Embodiment 1 of the present invention The characteristic diagram of the relationship between the peel strength. Fig. 21 shows the dependence of the peel strength of the tab wire 1 on the back silver bus bar electrode 17 of the solar cell 11 on the composition ratio of Ag in the solder.

The peel strength of the tab wire 1 to the back silver busbar electrode 17 depends on the Ag composition ratio of the tab wire 1, and the lower the Ag composition ratio, the lower the peel strength becomes. Accepting this result and in order to understand the reason why the peel strength of the chip wire 1 is lower when soldering the back silver busbar electrode 17 with the solder with a low Ag composition, observe the area of the chip wire 1 along the line AA in Figure 22 A cross-sectional image of the portion where the back silver bus bar electrode 17 is welded. Fig. 22 is a schematic perspective view showing the observation area of the cross-sectional image of the solar battery cell 11 after the sheet line 1 is welded using the solar battery module manufacturing method of the first embodiment of the present invention. In addition, the sheet wire 1 is actually welded, but this drawing shows the state after the sheet wire 1 is removed.

Figure 23 shows the solar cell when the solder plated Sn-0.3Ag-0.7Cu sheet wire 1 is soldered to the back silver bus electrode 17 according to the method for manufacturing the solar cell module in the first embodiment of the present invention The section of unit 11 is photographed. Fig. 23 is a scanning electron microscope showing the semiconductor substrate 31 constituting the solar battery cell 11, the backside silver bus bar electrode 17, the solder plating layer 1b and the copper foil 1a in the area along the line AA in Fig. 22 ( Scanning Electron Microscope: SEM) photography. Figure 24 is a schematic diagram showing Figure 23.

Figure 25 shows the solar energy when the solder plated wire 1 with Sn-3.0Ag-0.5Cu solder is soldered to the back silver bus electrode 17 according to the method of manufacturing the solar cell module of the first embodiment of the present invention The cross-section of the battery unit 11 is photographed. Figure 25 is a scanning electron microscope showing the semiconductor substrate 31 constituting the solar battery cell 11, the back silver busbar electrode 17, the solder plating layer 1b, and the copper foil 1a in the area along the line AA in Figure 22 (Scanning Electron Microscope: SEM) photograph. Figure 26 is a schematic diagram showing Figure 25.

The cross-sectional structure of the back electrode part after the sheet wire is attached to the back of the solar cell 11, the bonding strength is higher and the original cross-sectional structure is better, as shown in the SEM photograph in Figure 25 and the schematic diagram in Figure 26, the back side silver The Ag17a of the bus bar electrode 17 is a structure that uniformly exists between the solder plating layer 1b and the semiconductor substrate 31. That is, when the chip wire 1 using Sn-3.0Ag-0.5Cu solder and the back silver bus bar electrode 17 are soldered, it can be confirmed that the cross section of the structure is as expected.

On the other hand, when the chip wire 1 with Sn-0.3Ag-0.7Cu solder plated with solder is soldered to the back silver bus bar electrode 17, the cross-sectional structure of the back electrode after the chip wire is added is as shown in Figure 23. A part of the part where Ag17a should exist originally becomes the void 32. It is presumed that the existence of the void 32 is caused by the low peel strength as shown in FIG. 21. This phenomenon does not occur at the junction between the silver bus bar electrode 14 and the chip wire 1 on the light-receiving surface.

In addition, although the cross-sectional photograph is not shown, when soldering the chip wire 1 with Sn-1.0Ag-0.7Cu solder plated with solder to the back silver bus bar electrode 17, observe the cross-sectional structure of the back electrode portion after the chip wire is added. As a result, compared with the Sn-0.3Ag-0.7Cu solder, it can be observed that the gap 32 between the solder plating layer 1b and the semiconductor substrate 31 in the portion where Ag17a of the back silver bus electrode 17 should exist is relatively high. low. That is, although it also depends on the structure of the back silver bus bar electrode 17 formed, it can be confirmed by observation that the back electrode portion formed according to the solar cell module manufacturing method of the first embodiment uses solder plating When the chip wire 1 with Sn-3.0Ag-0.5Cu solder is used, there is no void 32 at all; compared with the chip wire 1 with Sn-0.3Ag-0.7Cu solder plated with solder, Sn-1.0 is used with solder plating The degree of void 32 generated in the chip wire 1 of Ag-0.7Cu solder is relatively low.

On the other hand, as shown in Fig. 21, since the peel strength depends on the composition ratio of Ag in the solder, from previous observations, it is estimated that the generation of voids 32 depends on the composition ratio of Ag of the solder plating layer of the chip wire 1. . Furthermore, when Sn-3.0Ag-0.5Cu solder is used, voids 32 are not generated in the part where Ag17a should originally exist, so Ag17a does not melt, and when Sn-1.0Ag-0.7Cu solder is used, voids 32 are generated. From the above situation, assuming that the Ag composition ratio of the lead-free solder is between 1.0% and 3.0%, and the back silver bus bar electrode 17 made of Ag has a non-melting Ag composition ratio, try to calculate that Ag becomes non-melting The melting limit of the Ag composition ratio.

The trial calculation is based on the gap 32 of the sample after the solder plated with Sn-3.0Ag-0.5Cu solder plated with Sn-3.0Ag-0.5Cu solder and the back silver busbar electrode 17 are soldered. Observe the cross-sectional part shown in Figure 23 at multiple places, and consider The volume of the void 32 and the volume of Ag17a adjacent to the void 32, and the volume of Ag17a of the void 32 is assumed to be the solder that melts to the opposite side of the void 32. As a result, the composition of the solder in which the back silver bus bar electrode 17 does not elute can be tentatively calculated as a composition containing about 2 wt% of Ag. The specification of the solder may be Sn-2.0Ag-0.5Cu.

However, the specifications of the lead-free solder actually circulating as obtained from the above trial calculation results are Sn-3.0Ag-0.5Cu solder with a higher Ag composition ratio than Sn-1.0Ag-0.7Cu solder. Therefore, in the first embodiment, Sn-3.0Ag-0.5Cu-based solder is selected at the end. Moreover, the composition of the Sn-Ag-Cu solder system solder is preferably from 2.0 wt% to 3.3 wt% of silver, 0.4 wt% to 3.0 wt% of copper, and tin as the remainder.

When the composition of the Sn-Ag-Cu solder is less than 2.0wt% of silver, when the chip wire 1 is soldered to the light-receiving silver busbar electrode 14 or the back-side silver busbar electrode 17, the light-receiving silver busbar electrode 14 Or, the silver in the back silver bus bar electrode 17 is eluted to the solder side, causing the resistance of the light-receiving surface silver bus bar electrode 14 or the back silver bus bar electrode 17 to increase. Therefore, in the composition of the Sn-Ag-Cu system solder, the silver system is preferably 2.0 wt% or more. In addition, when the composition of the Sn-Ag-Cu-based solder is more than 3.3 wt% of silver, the cost of the solder becomes higher. Therefore, in the composition of the Sn-Ag-Cu-based solder, the silver-based solder is preferably 3.3 wt% or less.

In the composition of Sn-Ag-Cu-based solder, when there is more copper, the melting point of the solder increases. Therefore, in order to solder the tab wire 1 in the range of heating temperature from 248°C to 264°C, the composition of the Sn-Ag-Cu-based solder is preferably 3.0 wt% or less of copper. In addition, when the chip wire 1 is manufactured, solder is applied to the periphery of the wire by immersing the copper wire in a solder bath. Here, when the copper wire is immersed in the solder tank, the copper of the copper wire is eluted into the solder tank, so the copper must be dissolved in the solder tank. Therefore, it is difficult to reduce the composition of copper in the solder. Therefore, when the chip wire 1 is manufactured by immersing the copper wire in a solder bath and coating the solder around the wire, the composition of the Sn-Ag-Cu solder is usually 0.4 wt% or more of copper.

As mentioned above, in the manufacturing method of the solar cell module of the first embodiment, Sn-3.0Ag-0.5Cu solder is selected as the lead-free solder, and the sheet wire 1 and the solar cell 11 are directly laminated on the heating plate 23. , And film line 1. Furthermore, after preheating the solar cell 11 and the chip wire 1 with the heating plate 23, the lamp heater 28 is used and controlled by a temperature graph suitable for the temperature rise and fall of the Sn-3.0Ag-0.5Cu solder The temperature of the solar cell 11. That is, the preheating temperature is set to 177°C to 183°C, and the heating temperature is set to 248°C to 264°C. Thereby, the existing equipment can be utilized to realize the welding of the sheet wire 1 with high joining reliability. Furthermore, by using the lamp heater 28 which has a fast heating response which is the response of ON and OFF, it is possible to perform the heating of the chip wire 1 and the solar cell 11 in a short time and with high accuracy.

In addition, in order to achieve proper welding, in addition to setting an appropriate temperature profile, it is necessary to appropriately set the pressing force of the sheet wire 1 during welding. In the manufacturing method of the solar cell module of the first embodiment, the The pressing force of the film line 1 is set from 1.0N to 3.5N per point. Thereby, it is possible to form a uniform solder fillet with high joining reliability, and it is possible to achieve welding with high joining reliability.

thus. According to the manufacturing method of the solar cell module of the first embodiment, it is possible to perform high-quality soldering of the solar cell 11 and the chip wire 1 using the existing equipment and the Sn-3.0Ag-0.5Cu-based lead-free solder. In this way, by welding the sheet wire 1 and the solar battery unit 11 with high reliability, the following effects can be achieved: a highly reliable interconnection between the solar battery unit 11 and the solar battery unit 11 can be obtained. Solar cell modules.

The configuration shown in the above embodiment shows an example of the content of the present invention, and can also be combined with another conventional technology, and part of the configuration can be omitted or changed without departing from the scope of the present invention.

S10‧‧‧ Film line preparation steps

S20‧‧‧Flux coating step

S30‧‧‧First piece line configuration steps

S40‧‧‧Solar battery unit configuration steps

S50‧‧‧Second piece line configuration steps

S60‧‧‧Pressing steps

S70‧‧‧Pre-heating step

S80‧‧‧Heating step

Claims (9)

A method for manufacturing a solar cell module, which is characterized by comprising the following steps: a step of providing a plurality of heating plates with sheet line grooves; a flux coating step, which is to coat the flux on the first surface of the solar cell unit The connection electrode and the second surface connection electrode, wherein the solar cell has a first surface and a second surface opposite to the first surface, the first surface connection electrode is provided on the first surface, and the second surface connection electrode is provided on the The second surface; the lamination step, which is to arrange the first sheet wire whose surface is covered with lead-free solder in the sheet line groove, and place the first sheet wire and the second surface as the above-mentioned upwards in order from bottom to top The solar battery cell and the second sheet wire whose surface is covered with lead-free solder are laminated on one of the aforementioned plurality of heating plates; the pressing step is to press the second sheet wire from above using a pressing device; the pre-heating step, It uses the heating plate to preheat the solar battery unit to a predetermined preheating temperature; the heating step uses the infrared light of a lamp heater to heat the solar battery unit to the predetermined heating temperature from the second surface side; and The step of sliding the plurality of heating plates or the lamp heaters along the line grooves. As for the manufacturing method of solar cell module described in item 1 of the scope of patent application, the lamination step has the following steps: the first piece wire arrangement step, which is to arrange the aforementioned first piece wire in the piece wire groove, the piece The line groove is set on the heating plate corresponding to the solar cell The position of the connection electrode on the first side of the cell; the solar cell arrangement step is to make the position of the connection electrode on the first side coincide with the position of the first sheet wire and arrange the solar cell on the heating plate; and The second sheet wire arranging step is to arrange the second sheet wire on the second surface connection electrode of the solar battery cell. The method for manufacturing a solar cell module as described in claim 1, wherein the flux coating step is to coat the first solar cell unit and the second solar cell unit of the solar cell unit with the flux in the aforementioned flux coating step; In the lamination step, the first solar cell and the second solar cell are arranged adjacent to each other, and the first surface of the first solar cell is connected to the second solar cell using the first sheet wire. The second surface of the unit is connected to the electrode to form a solar cell series; in the heating step, the first solar cell and the second solar cell are individually heated; the pre-heating step is to maintain the pre-heated Until the heating step of the first solar cell and the second solar cell is completed. The method for manufacturing a solar cell module as described in item 1 or 2 of the scope of patent application, wherein the preheating temperature in the preheating step is from 177°C to 183°C, and the heating temperature in the heating step is 248°C Up to 264°C. The manufacturing method of solar cell module as described in item 1 or 2 of the scope of patent application, wherein in the heating step, the solar cell unit is previously The time for heating the preheating temperature to the heating temperature is from 3.6 seconds to 3.8 seconds; after the heating step, the time for cooling the solar cell unit from the heating temperature to the preheating temperature is from 7.0 seconds to 9.0 seconds. According to the method for manufacturing a solar cell module described in item 1 or 2 of the scope of the patent application, in the pressing step, the pressing force for pressing the second sheet line is from 1.0N to 3.5N per point. According to the method for manufacturing a solar cell module described in item 1 or 2 of the scope of the patent application, the first sheet wire and the second sheet wire are formed by covering the surface of the copper wire with Sn-Ag-Cu solder. The manufacturing method of the solar cell module as described in item 7 of the scope of patent application, wherein the composition of the aforementioned Sn-Ag-Cu solder is 2.0wt% to 3.3wt% for silver and 0.4wt% to 3.0wt% for copper %, the remainder is tin. According to the method of manufacturing a solar cell module described in item 1 or 2 of the scope of patent application, the aforementioned flux system has an ester compound, a rosin resin acid or a modified rosin.

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