WO2018142544A1 - Solar cell module and method for manufacturing solar cell module - Google Patents

Abstract

A solar cell module (1), provided with: n-type first crystalline solar cells in which the light-receiving surface side serves as the positive electrode; and p-type second crystalline solar cells in which the light-receiving surface side serves as the negative electrode, the second crystalline solar cells being arranged so as to alternate with the first crystalline secondary cells. The solar cell module (1) is characterized in being provided with: a plurality of light-receiving surface-side connection wires connecting the respective light-receiving surface-side electrodes of adjacent first and second crystalline solar cells and comprising six or more metal wire lines (11) which are made of a metal and which have a circular cross-section having a diameter in the range of 0.2-1.0 mm; and reverse surface-side connection wires comprising metal films (12) connecting the respective reverse surface-side electrodes of adjacent first and second crystalline solar cells, the reverse surface side being opposite the light-receiving surface side.

Description

Solar cell module and method for manufacturing solar cell module

The present invention relates to a solar cell module including a plurality of solar cells and a method for manufacturing the solar cell module.

Currently, the warranty period for solar cell modules has been extended to about 25 years. The solar cell module is required to have high reliability and high photoelectric conversion efficiency. The most common deterioration in solar cell modules is disconnection of the connection between solar cells. It is known that the main cause of the disconnection failure is a defect in the connection portion and a disconnection failure in the tab line. Tab wire breakage is due to fatigue of the tab wire, and in particular, a large curvature that is disposed from the surface of one solar cell to the back surface of the other solar cell among adjacent solar cells. It is easy to occur in part.

On the other hand, solar cells with different polarities are alternately arranged, that is, p-type solar cells and n-type solar cells are alternately arranged, and the surface of one solar cell to the other solar cell. It is known that it is possible to eliminate the wrapping of the tab line to the back surface of the cell. In Patent Document 1, an n-type solar cell in which an n-type silicon substrate is used and a light-receiving surface is a positive electrode and a back surface is negative, and a p-type silicon substrate is used and a light-receiving surface is a negative electrode and a back surface is a positive electrode. A solar cell module in which the p-type solar cells are arranged alternately is disclosed. In the solar cell module described in Patent Literature 1, the bus bar electrode portions on the light receiving surface side of adjacent solar cells are connected to each other by a surface-side connection tab made of a metal wire. Moreover, the bus-bar electrode parts of the back surface side of an adjacent photovoltaic cell are connected by the back surface side connection tab which consists of striped metal foil.

However, in the solar cell module described in Patent Document 1, the bus bar electrode portions on the light receiving surface side of the adjacent solar cells are connected to each other by the front surface side connection tab made of a metal ribbon, and the back surface side of the adjacent solar cell is The bus bar electrode portions are connected to each other by a back surface side connection tab made of a striped metal foil. That is, since adjacent photovoltaic cells are connected via the bus electrode and the connection tab, significant improvement in photoelectric conversion efficiency cannot be expected. In addition, since the number of front side connection tabs is smaller than the number of back side connection tabs, effective current transfer from the current source to the front side connection tabs is possible due to the small number of front side connection tabs on the front side. Since the distance becomes longer, the electrical resistance increases and a significant improvement in photoelectric conversion efficiency cannot be expected.

On the other hand, as a method for achieving high photoelectric conversion efficiency of the solar cell module, a multi-wire method in which a large number of metal wire wires are directly joined to the grid electrode on the solar cell without using the bus bar electrode has attracted attention. In the multi-wire method, since the effective distance of current movement from the current source to the metal wire wire is shortened by increasing the number of metal wires of the metal wire, the electric resistance is reduced and the solar cell module is It becomes possible to increase the photoelectric conversion efficiency.

As a technique using a multi-wire system, Patent Document 2 discloses a photovoltaic cell having a transparent conductive film on the surface, a finger electrode provided in contact with the transparent conductive film and serving as a collecting electrode, and orthogonal to the finger electrode. A solar cell module having a plurality of metal wires arranged as interconnectors and having finger electrodes formed in a broken line shape is disclosed.

JP 2007-103536 A JP 2014-146697 A

However, when the inventors made and evaluated the solar cell module described in Patent Document 2, a decrease in photoelectric conversion efficiency was observed in the heat cycle test. The cause of the decrease in photoelectric conversion efficiency in the heat cycle test is a crack in the solar battery cell due to an increase in the number of metal wires connecting the electrode on the light receiving surface and the electrode on the back surface of the adjacent solar battery cell. There was found. That is, since a large number of metal wires are bent between adjacent solar cells and mounted on the solar cells, the burden on the solar cells is increased and the solar cells are cracked, resulting in a decrease in photoelectric conversion efficiency. To do. From this, like the solar cell module adopting the multi-wire system described in Patent Document 2, when the electrodes on the light receiving surface and the back electrode of adjacent solar cells are connected using a large number of metal wires, It has been found that a large stress is applied to the battery cell, the solar cell is easily cracked, and the reliability is lowered.

This invention is made | formed in view of the above, Comprising: It aims at obtaining the solar cell module which can improve a photoelectric conversion efficiency and reliability.

In order to solve the above-described problems and achieve the object, a solar cell module according to the present invention includes an n-type first crystalline solar cell having a light-receiving surface as a positive electrode, and alternating first crystalline solar cells. And a p-type second crystalline solar cell in which the light receiving surface side is the negative electrode. In addition, the solar cell module connects the electrodes on the light receiving surface side of the adjacent first crystal solar cell and second crystal solar cell, and has a circular shape with a diameter in the range of 0.2 mm to 1.0 mm. A plurality of light-receiving surface side connection wirings made of six or more metal metal wire wires having a cross-section, and the light-receiving surface sides of the adjacent first crystal solar cells and second crystal solar cells. And a back-side connection wiring made of a metal film for connecting the back-side electrodes to each other.

The solar cell module according to the present invention has an effect that the photoelectric conversion efficiency and the reliability can be improved.

The schematic top view which looked at the array wiring of the solar cell array of the solar cell module concerning Embodiment 1 of this invention from the light-receiving surface side The schematic bottom view which looked at the array wiring of the solar cell array of the solar cell module concerning Embodiment 1 of this invention from the back surface side facing a light-receiving surface side Schematic sectional view showing the solar cell module according to the first embodiment of the present invention. The schematic top view which looked at the n-type photovoltaic cell concerning Embodiment 1 of this invention from the light-receiving surface side The schematic bottom view which looked at the n-type photovoltaic cell concerning Embodiment 1 of this invention from the back surface side facing a light-receiving surface side Schematic sectional view showing an n-type solar cell according to the first embodiment of the present invention. The schematic top view which looked at the p-type photovoltaic cell concerning Embodiment 1 of this invention from the light-receiving surface side The schematic bottom view which looked at the p-type photovoltaic cell concerning Embodiment 1 of this invention from the back surface side Schematic sectional view showing a p-type solar cell according to the first embodiment of the present invention. Schematic sectional view showing another configuration example of the p-type solar cell according to the first embodiment of the present invention. Schematic bottom view showing an example of an electrode-integrated back sheet in which the metal film and the back sheet according to the first embodiment of the present invention are integrated. Schematic sectional view showing an example of an electrode-integrated backsheet in which the metal film and the backsheet according to the first embodiment of the present invention are integrated. The schematic top view which shows the state by which the n-type photovoltaic cell concerning Embodiment 1 of this invention and the p-type photovoltaic cell were connected by the metal wire wire. The schematic cross section which shows the state by which the n-type photovoltaic cell concerning Embodiment 1 of this invention and the p-type photovoltaic cell were connected by the metal wire wire. The schematic top view which shows the laminated body before the lamination concerning Embodiment 1 of this invention Schematic sectional view showing the laminate before lamination according to the first embodiment of the present invention. The schematic bottom view which looked at the solar cell array produced by arrange | positioning the ribbon-shaped metal film on the back surface of an n-type photovoltaic cell and a p-type photovoltaic cell in Example 3 from the back surface side. Schematic cross-sectional view of a solar cell array produced by arranging a ribbon-like metal film on the back surfaces of an n-type solar cell and a p-type solar cell in Example 3 Schematic top view showing the laminate before lamination in Example 3 Schematic sectional view showing the laminate before lamination in Example 3 The schematic bottom view which looked at the array wiring of the solar cell array of the solar cell module of Example 3 from the back surface side Schematic sectional view showing the solar cell module of Example 3 Schematic top view showing the laminate before lamination in Example 4 Schematic cross-sectional view showing the laminate before lamination in Example 4 The schematic bottom view which looked at the array wiring of the solar cell array of the solar cell module of Example 4 from the back surface side Schematic sectional view showing the solar cell module of Example 4 The figure which shows the result of the evaluation test of the solar cell module of Example 1 to Example 4 and Comparative Example 1 to Comparative Example 5.

Hereinafter, a solar cell module and a method for manufacturing the solar cell module according to an embodiment of the present invention will be described in detail based on the drawings. In addition, this invention is not limited to the following description, In the range which does not deviate from the summary of this invention, it can change suitably. In the drawings shown below, the scale of each member may be different from the actual scale for easy understanding. The same applies between the drawings.

Embodiment 1 FIG.
FIG. 1 is a schematic top view of an array wiring of a solar cell array of a solar cell module 1 according to a first embodiment of the present invention as viewed from the light receiving surface side. FIG. 2 is a schematic bottom view of the array wiring of the solar cell array of the solar cell module 1 according to the first embodiment of the present invention as viewed from the back surface side facing the light receiving surface side. FIG. 3 is a schematic cross-sectional view showing the solar cell module 1 according to the first embodiment of the present invention, which is a cross-sectional view taken along the line III-III in FIG. In FIG. 1, two orthogonal directions indicated by arrows X and Y are referred to as a column direction and a row direction, respectively. In addition, the figure seen from the light-receiving surface side is a top view, and the figure seen from the opposite side is a bottom view.

The solar cell module 1 according to the first embodiment is configured by n-type solar cells 10n and p-type solar cells 10p, which are two types of solar cells 10 arranged in a matrix in the column direction and the row direction. A solar cell array. The n-type solar cell 10n is a first crystalline solar cell in which an n-type crystalline silicon substrate is used, a light receiving surface is a positive electrode, and a back surface opposite to the light receiving surface is a negative electrode. The p-type solar cell 10p is a second crystalline solar cell in which a p-type crystalline silicon substrate is used, the light receiving surface is a negative electrode, and the back surface is a positive electrode. Hereinafter, when the n-type solar battery cell 10n and the p-type solar battery cell 10p are not distinguished, they may be simply referred to as the solar battery cell 10.

In each row of the solar cell array of the solar cell module 1, n-type solar cells 10n and p-type solar cells 10p are alternately arranged. A plurality of n-type solar cells 10n and p-type solar cells 10p arranged in each row are adjacent to each other by a plurality of metal wire lines 11 that are light-receiving surface side connection wires and a metal film 12 that is a back surface side connection wire. The cells 10 are electrically connected in series.

Further, in FIG. 1, the solar cells 10 at the end of each row are electrically connected in series with the solar cells 10 at the end of adjacent rows and the horizontal tab wires 13. Thereby, all the photovoltaic cells 10 in the solar cell module 1 are electrically connected in series. Moreover, the cable which is not shown in figure which connects to a terminal box is connected to the metal film 12 of the photovoltaic cell 10 located in the both ends of series connection.

As shown in FIG. 1 and FIG. 3, the positive electrode on the light-receiving surface side of the n-type solar cell 10n is disposed on the light-receiving surface side of the n-type solar cell 10n and the p-type solar cell 10p adjacent in each row. A plurality of metal wire wires 11 are provided to electrically connect the negative electrode on the light receiving surface side of the p-type solar battery cell 10p in series. In FIGS. 1 to 3, the electrodes of the solar battery cell 10 are omitted. The detail of the electrode of the photovoltaic cell 10 is mentioned later. The metal wire lines 11 extend parallel to each other along the column direction. A set of solar battery cells 10 is configured by adjacent n-type solar battery cells 10n and p-type solar battery cells 10p connected to each other by metal wire wires 11. That is, the metal wire 11 is joined to the positive electrode provided on the light receiving surface of the n-type solar cell 10n and the negative electrode on the light receiving surface side of the p-type solar cell 10p in the same set. Thus, the plurality of n-type solar cells 10n and the p-type solar cells 10p in each row are electrically connected in series by a multi-wire method using the plurality of metal wire wires 11.

Moreover, as shown in FIG. 1 and FIG. 3, on the back side of the n-type solar cell 10n and the p-type solar cell 10p adjacent in each row, the negative electrode on the back side of the n-type solar cell 10n A metal film 12 that electrically connects the positive electrode on the back surface side of the p-type solar battery cell 10p in series is provided. The metal films 12 extend in parallel to each other along the row direction. The metal film 12 electrically connects the electrode on the back surface side of one solar cell 10 and the electrode on the back surface side of the other solar cell 10 in a set of solar cells 10 adjacent to each other in different sets. Connecting. That is, the metal wire 11 is joined to the positive electrode provided on the light receiving surface of the n-type solar cell 10n and the negative electrode on the light receiving surface side of the p-type solar cell 10p in the same set.

The plurality of solar cells 10 are sealed with a sealing material 22 made of a light-transmitting resin, and a glass substrate 21 that is a light-transmitting light-receiving surface side protection member is provided on the light-receiving surface side of the sealing material 22. A back sheet 23, which is a back surface side protection member, is provided on the back surface side of the sealing material 22. As the sealing material 22, a thermosetting resin having translucency such as an ethylene vinyl acetate copolymer (Ethylene-Vinyl Acetate: EVA) can be used. A light-transmitting material such as transparent glass or transparent film can be used for the light-receiving surface side protection member.

As the back sheet 23, a single layer resin sheet or a laminated resin sheet in which a plurality of resin sheets are laminated can be used. In the first embodiment, a back sheet made of polyethylene terephthalate (PET) is used.

FIG. 4 is a schematic top view of the n-type solar battery cell 10n according to the first embodiment of the present invention as viewed from the light-receiving surface side. FIG. 5 is a schematic bottom view of the n-type solar cell 10n according to the first embodiment of the present invention as viewed from the back surface side facing the light receiving surface side. FIG. 6 is a schematic cross-sectional view showing the n-type solar cell 10n according to the first embodiment of the present invention, and is a cross-sectional view taken along the line VI-VI in FIG. The n-type solar battery cell 10n has a structure of a general solar battery cell that is mass-produced as an n-type solar battery cell, and has a maximum photoelectric conversion efficiency of about 20%.

The n-type solar battery cell 10n is a crystalline solar battery cell using a crystalline semiconductor substrate. In n-type solar cell 10n, p-type impurity diffusion layer 32, which is an impurity diffusion layer, is formed by boron diffusion on the light-receiving surface side of n-type silicon layer 31 made of an n-type silicon substrate, which is an n-type semiconductor substrate. ing. The n-type silicon substrate may be a single crystal silicon substrate or a polycrystalline silicon substrate.

A depletion layer 33 is formed in the vicinity of the junction surface between the n-type silicon layer 31 and the p-type impurity diffusion layer 32. In addition, on the surface of the n-type silicon layer 31 on the light receiving surface side, minute unevenness (not shown) is formed as a texture structure. The micro unevenness increases the area for absorbing light from the outside on the light receiving surface, suppresses the reflectance on the light receiving surface, and has a structure for confining light. Further, an antireflection film may be provided on the surface of the n-type silicon layer 31 on the light receiving surface side.

Further, on the light-receiving surface side of the n-type solar cell 10n, that is, on the light-receiving surface side on the p-type impurity diffusion layer 32, there are a plurality of light-receiving surface electrodes made of an electrode material containing silver and glass and having an elongated shape. A grid electrode 34 is provided in electrical connection with the p-type impurity diffusion layer 32 on the bottom surface. That is, the plurality of grid electrodes 34 constitute a light receiving surface electrode that functions as a positive electrode.

On the other hand, a back surface aluminum electrode 35 made of an electrode material containing aluminum and glass is provided on the back surface side of the n-type solar cell 10n, that is, the back surface side of the n-type silicon layer 31, covering the entire back surface. That is, the back surface aluminum electrode 35 constitutes a back surface electrode that functions as a negative electrode.

The plurality of metal wire lines 11 are arranged on the grid electrode 34 in a state where the longitudinal direction of the metal wire line 11 and the longitudinal direction of the grid electrode 34 of the n-type solar battery cell 10n are orthogonal to each other. In FIG. 4, the arrangement position of the metal wire 11 on the light receiving surface side of the n-type solar cell 10n is indicated by a dotted line. Moreover, the metal film 12 is arrange | positioned on the back surface aluminum electrode 35 in the state to which the longitudinal direction of the metal film 12 and the longitudinal direction of the grid electrode 34 of 10 n of n-type photovoltaic cells orthogonally crossed. In FIG. 5, the arrangement position of the metal film 12 on the back surface side of the n-type solar battery cell 10n is indicated by a dotted line.

FIG. 7 is a schematic top view of the p-type solar battery cell 10p according to the first embodiment of the present invention as viewed from the light-receiving surface side. FIG. 8 is a schematic bottom view of the p-type solar battery cell 10p according to the first embodiment of the present invention viewed from the back side. FIG. 9 is a schematic cross-sectional view showing the p-type solar cell 10p according to the first embodiment of the present invention, and is a cross-sectional view taken along the line IX-IX in FIG.

The p-type solar battery cell 10p is a crystalline solar battery cell using a crystalline semiconductor substrate. In p-type solar cell 10p, n-type impurity diffusion layer 42, which is an impurity diffusion layer, is formed by phosphorous diffusion on the light-receiving surface side of p-type silicon layer 41 made of a p-type silicon substrate that is a p-type semiconductor substrate. ing. A depletion layer 43 is formed near the junction surface between the p-type silicon layer 41 and the n-type impurity diffusion layer 42. Further, on the surface of the p-type silicon layer 41 on the light-receiving surface side, fine unevenness (not shown) is formed as a texture structure. The micro unevenness increases the area for absorbing light from the outside on the light receiving surface, suppresses the reflectance on the light receiving surface, and has a structure for confining light. An antireflection film may be provided on the light receiving surface side of the p-type silicon layer 41.

In addition, on the light receiving surface side of the p-type solar cell 10p, that is, the light receiving surface side of the n-type impurity diffusion layer 42, a plurality of grid electrodes 44 made of an electrode material containing silver and glass and having an elongated shape are provided on the bottom surface. Are electrically connected to the n-type impurity diffusion layer 42. That is, the plurality of grid electrodes 44 constitute a light receiving surface electrode that functions as a negative electrode.

On the other hand, a back surface passivation film 46 made of a silicon nitride film is provided on the entire back surface of the p-type silicon layer 41. Note that a silicon oxide film may be used for the back surface passivation film 46. The back surface passivation film 46 is provided with a dot-like contact hole 46 a that reaches the back surface of the p-type silicon layer 41. On the back surface passivation film 46, a back surface aluminum electrode 45 made of an electrode material containing aluminum and glass is provided to fill the contact hole 46a and cover the entire surface of the back surface passivation film 46. That is, the back surface aluminum electrode 45 constitutes a back surface electrode that works as a positive electrode.

The plurality of metal wire lines 11 are arranged on the grid electrode 44 in a state where the longitudinal direction of the metal wire line 11 and the longitudinal direction of the grid electrode 44 of the p-type solar battery cell 10p are orthogonal to each other. In FIG. 7, the arrangement | positioning position of the metal wire wire 11 in the light-receiving surface side of the p-type photovoltaic cell 10p is shown with the dotted line. Moreover, the metal film 12 is arrange | positioned on the back surface aluminum electrode 45 in the state in which the longitudinal direction of the metal film 12 and the longitudinal direction of the grid electrode 44 of the p-type photovoltaic cell 10p were orthogonally crossed. In FIG. 8, the arrangement | positioning position of the metal film 12 in the back surface side of the p-type photovoltaic cell 10p is shown with the dotted line.

In the contact hole 46a, an alloy layer 47 of aluminum and silicon is formed between the p-type silicon layer 41 and the back surface aluminum electrode 45. Further, in a region adjacent to the alloy layer 47 on the back surface side of the p-type silicon layer 41, aluminum is diffused from the back surface aluminum electrode 45 to the back surface side of the p-type silicon layer 41, so that the p-type impurity is higher than the p-type silicon layer 41. A back surface field (BSF) layer 48 that is a p + region having a high concentration is formed. The back surface aluminum electrode 45 is electrically connected to the p-type silicon layer 41 through the alloy layer 47 and the BSF layer 48.

The p-type solar cell 10p shown in FIGS. 7 to 9 is a back-passive type cell (Passivated Emitter and Rear Cell: PERC) formed in the same size as the n-type solar cell 10n. In the PERC cell, the recombination occurring at the interface between the p-type silicon layer on the back surface of the solar cell and the aluminum electrode is reduced by using a passivation film provided on the back surface of the solar cell, thereby improving the photoelectric conversion efficiency. It is a solar cell that can be used. The photoelectric conversion efficiency of a general p-type single crystal solar cell that does not have a passivation film on the back surface is about 16%. On the other hand, when the PERC cell is used, it is possible to improve the photoelectric conversion efficiency up to about 20%.

Generally, the n-type solar cell generates a larger current than the p-type solar cell. For this reason, when n-type solar cells 10n and p-type solar cells 10p are alternately connected in series, the amount of current generated by n-type solar cells 10n and the current generated by p-type solar cells 10p The amount of current is different from the amount. A loss occurs in the photoelectric conversion efficiency of the solar cell module due to the difference in current amount, that is, the output difference. Further, when there is a difference between the amount of current generated by the n-type solar cell 10n and the amount of current generated by the p-type solar cell 10p, even if a bypass diode is provided, the amount of current generated is small. Type solar cells tend to be hot spots. Then, the occurrence of discoloration due to the heat of the backsheet or the constant current conduction of the diode due to defective soldering, and then the occurrence of a state in which the defective diode and further heat generation of the defective soldering part may occur.

For this reason, in this Embodiment 1, the p-type photovoltaic cell 10p uses the p-type photovoltaic cell of the type which can implement | achieve high photoelectric conversion efficiency, and the power generation characteristic of the p-type photovoltaic cell 10p is n-type solar. It is close to the power generation characteristics of the battery cell 10n. Specifically, by using the above-described PERC cell for the p-type solar cell 10p, the power generation characteristic of the p-type solar cell 10p is brought close to the power generation characteristic of the n-type solar cell.

That is, the n-type solar cell 10n according to the first embodiment is an n-type solar cell having a maximum photoelectric conversion efficiency of about 20%. On the other hand, the p-type solar battery cell 10p which is a PERC cell also has a photoelectric conversion efficiency of about 20%. In the first embodiment, the difference in the amount of current during power generation between the n-type solar cell 10n and the p-type solar cell 10p is within ± 5%. Thereby, in this Embodiment 1, in n-type photovoltaic cell 10n and p-type photovoltaic cell 10p, connecting n-type photovoltaic cell 10n and p-type photovoltaic cell 10p with which polarity differs alternately in series. The amount of generated current can be balanced, and the occurrence of a loss of photoelectric conversion efficiency due to the occurrence of hot spots and output differences can be prevented.

FIG. 10 is a schematic cross-sectional view showing another configuration example of the p-type solar battery cell 10p according to the first embodiment of the present invention. As a p-type solar cell of a type capable of realizing high photoelectric conversion efficiency in order to bring the power generation characteristic of the p-type solar battery cell 10p close to the power generation characteristic of the n-type solar battery cell 10n, in addition to the above-described PERC cell, Q. manufactured by Q Cell Corporation shown in FIG. As in the ANTUM cell (registered trademark), a solar battery cell that reflects light passing through the silicon substrate and reuses it for power generation can be used.

In the solar cell shown in FIG. 10, a plurality of n-type impurity diffusion layers 52, depletion layers 53, and light-receiving surface electrodes are provided on the light-receiving surface side of a p-type silicon layer 51 made of a p-type silicon substrate which is a p-type semiconductor substrate. Grid electrode 54 is provided. On the back side of the p-type silicon layer 51, a metal layer is provided as a reflective coating layer 56 between the p-type silicon layer 51 and the back surface aluminum electrode 55. In this solar cell, the photoelectric conversion efficiency can be improved by reflecting the light passing through the p-type silicon layer 51 to the back side by the reflective coating layer 56 and reusing it for power generation. In particular, this technique has a great effect when applied to a thin solar cell that easily transmits light. For example, when applied to solar cells having a thickness of 150 μm or less, the effect of improving photoelectric conversion efficiency is great. The reflective coating layer 56 can be formed, for example, by forming a metal film on the back side of the p-type silicon layer 51.

Moreover, in order to make the power generation characteristics of the p-type solar cell 10p and the n-type solar cell 10n electrically connected in series close to each other, the solar cell having the same structure as the p-type solar cell and the n-type solar cell. Using the cell, the cell size of the p-type solar cell may be larger than the cell size of the n-type solar cell. That is, the current value of each solar cell is controlled by the difference in cell size between the p-type solar cell and the n-type solar cell having the same power generation characteristic, and the power generation characteristic of the p-type solar cell is changed to the n-type solar cell. It is also possible to approximate the power generation characteristics of the battery cell.

The metal wire 11 is a metal wiring made of a metal wire. The cross-sectional shape of the metal wire 11 is preferably circular. Since the cross-sectional shape of the metal wire line 11 is circular, sunlight hitting the metal wire line 11 becomes reflected light that is reflected in various directions, and the reflected light is incident on the solar battery cell 10 and has a photoelectric conversion efficiency. Contributes to improvement.

When the cross-sectional shape of the metal wire line 11 is an ellipse, when the plurality of metal wire lines 11 are arranged so that the arrangement direction of the plurality of metal wire lines 11 is along the long axis direction of the ellipse, The area shaded by the metal wire 11 on the light receiving surface 10 increases. Thereby, the sunlight which injects into the photovoltaic cell 10 decreases, and the photoelectric conversion efficiency of the photovoltaic cell 10 falls. Further, when the plurality of metal wire wires 11 are arranged so that the arrangement direction of the plurality of metal wire wires 11 is along the minor axis direction of the ellipse, the contact area between the metal wire wire 11 and the grid electrode is reduced. Thereby, since the joining area of the metal wire wire 11 and the grid electrodes 34 and 44 is reduced and the metal wire wire 11 is easily detached from the grid electrodes 34 and 44, the connection between the metal wire wire 11 and the grid electrodes 34 and 44 is achieved. Inferior in reliability.

On the other hand, when the cross-sectional shape of the metal wire wire 11 is circular, the balance between the photoelectric conversion efficiency of the solar battery cell 10 and the connection reliability between the metal wire wire 11 and the grid electrode is appropriately maintained. Furthermore, it is not necessary to align the cross section in the circumferential direction when connecting to the grid electrode.

The diameter of the metal wire 11 is preferably in the range of 0.2 mm to 1.0 mm. That is, the diameter of the metal wire 11 used in the multi-wire system has an appropriate range. When the diameter of the metal wire 11 is thinner than 0.2 mm, the contact area with the grid electrodes 34 and 44 is reduced. Thereby, since the joining area of the metal wire line 11 and the grid electrodes 34 and 44 is reduced, the metal wire line 11 is easily detached from the grid electrodes 34 and 44. Connection reliability is poor. Moreover, when the diameter of the metal wire line 11 is thicker than 1.0 mm, the area | region which becomes shade with the metal wire line 11 in the light-receiving surface of the photovoltaic cell 10 increases. Thereby, the sunlight which injects into the photovoltaic cell 10 decreases, and the photoelectric conversion efficiency of the photovoltaic cell 10 falls.

The number of metal wire wires 11 is preferably in the range of 6 to 16 in the case of a 156 mm square solar battery cell 10 having, for example, round chamfered shapes at four corners. In the first embodiment, the number of metal wire wires 11 is seven. When the number of the metal wire lines 11 is less than 6, it is easily influenced by the resistance component of the grid electrodes 34 and 44, and the photoelectric conversion efficiency is lowered. When the number of the metal wire lines 11 is greater than 17, the resistance components of the grid electrodes 34 and 44 decrease, but the area shaded by the metal wire lines 11 on the light receiving surface of the solar battery cell 10 increases. Thereby, the sunlight which injects into the photovoltaic cell 10 decreases, and the photoelectric conversion efficiency of the photovoltaic cell 10 falls.

As such a metal wire 11, for example, a copper wire having high conductivity is used. As a connection method between the metal wire line 11 and the grid electrodes 34 and 44, a bonding method in which a bonding object is interposed between the metal wire line 11 and the grid electrodes 34 and 44 can be used. As a joint to be inserted between the metal wire wire 11 and the grid electrodes 34, 44, a solder, a conductive adhesive, a metal paste, an anisotropic conductive film is provided between the metal wire wire 11 and the grid electrodes 34, 44. (Anisotropic Conductive Film: ACF) or conductive double-sided tape can be used. By using solder, conductive adhesive, metal paste, ACF or conductive double-sided tape, the connection between the metal wire 11 and the grid electrodes 34 and 44 can be strengthened.

In addition, as a method of connecting the metal wire line 11 and the grid electrodes 34 and 44, the metal wire line 11 is brought into contact with the grid electrodes 34 and 44 from above the metal wire line 11 and the grid electrodes 34 and 44. A method of pressing with a tape, a sheet, or a gel can be used. When the metal wire wire 11 and the grid electrodes 34 and 44 are pressed from above the tape, a sheet, or a gel, the tape, the sheet, or the gel is transparent and excellent in light transmittance. In addition, pressure welding using a sealing material can be used.

In the first embodiment, the metal wire wire 11 that has been pre-coated with solder is heated while pressing the metal wire wire 11 against the grid electrodes 34 and 44, so that the solder is melted and the metal wire wire 11 is grid-off. Bonded to the electrodes 34 and 44.

The metal film 12 is made of a foil, a film, or a film, and is a metal wiring that is wider than the metal wire line 11. In the present embodiment, the metal foil, the metal film, or the metal film is collectively referred to as a metal film. Since the metal film 12 has a flat film shape and makes a surface connection with the back surface aluminum electrodes 35 and 45 on the back surface of the solar battery cell 10, the connection resistance with the back surface aluminum electrodes 35 and 45 can be reduced. In addition, the stress applied to the solar battery cell 10 can be reduced.

For example, copper having high conductivity is used as the material of the metal film 12. In the first embodiment, a copper foil that is a metal foil is used as the metal film 12. The quantity of the metal film 12 which connects the photovoltaic cells 10 is not specifically limited, One or more sheets may be sufficient and two or more sheets may be sufficient. A plurality of ribbon-shaped metal films 12 may be used. In the first embodiment, a single copper foil is used as the metal film 12.

Since the back surface of the solar battery cell 10 does not need to be exposed to light, the metal film 12 preferably has a shape that maintains low electrical resistance bonding and does not apply stress to the solar battery cell 10. That is, in the case of a solar battery module structure using an opaque back sheet, the back surface of the solar battery cell 10 does not need to transmit sunlight, so that the connection between adjacent solar battery cells 10 is a multi-wire system. There is no need to use it. And the stress concerning the photovoltaic cell 10 can be reduced by using foil-shaped, film-shaped, or film-shaped connection wiring, and the malfunction by a cell crack can be reduced.

The thickness of the metal film 12 is preferably 0.02 mm or more and 0.3 mm or less. When the thickness of the metal film 12 is less than 0.02 mm, the electric resistance of the metal film 12 is increased, and the handling of the metal film 12 becomes difficult. Moreover, when the thickness of the metal film 12 is thicker than 0.3 mm, it is caused by a step formed by the surface of the back surface aluminum electrodes 35 and 45 on the back surface of the solar battery cell 10 and the metal film 12 at the time of lamination. Stress is applied to the solar cells 10, and cell cracks are likely to occur in the solar cells 10. Further, considering the conductivity of the metal film 12, a thickness of the metal film 12 of 0.3 mm or less is sufficient.

As a method of connecting the solar cells 10 using the metal film 12, a metal foil or a metal ribbon as a single metal film 12 provided separately from the back sheet is used as the back surface aluminum electrode 35 on the back surface of the solar cell 10. , 45 can be bonded to the surface. As a method for connecting the metal film 12 and the back surface aluminum electrodes 35 and 45, a bonding method in which a bonding material is interposed between the metal film 12 and the back surface aluminum electrodes 35 and 45 can be used. As a joint to be inserted between the metal film 12 and the back surface aluminum electrodes 35 and 45 on the back surface of the solar battery cell 10, solder, conductive adhesive, metal paste, ACF or conductive double-sided tape can be used. By using solder, conductive adhesive, metal paste, ACF or conductive double-sided tape, the connection between the metal film 12 and the back surface aluminum electrodes 35 and 45 can be strengthened.

As another method, an electrode-integrated back sheet in which the metal film 12 and the back sheet are integrated is placed on the surfaces of the back surface aluminum electrodes 35 and 45, and a solar cell module is laminated to form a metal film. 12 is a method of connecting the solar cells 10 to each other.

As a method of integrating the metal film 12 and the back sheet, a method of performing metal plating on one side of the back sheet, a method of thermocompression bonding a metal foil to the back sheet, and a back sheet of the metal film 12 using an adhesive It is possible to apply a method such as pasting to. In any method, after the metal foil is integrated with the back sheet, the metal foil must be patterned by etching.

FIG. 11 is a schematic bottom view showing an example of an electrode-integrated back sheet in which the metal film 12 and the back sheet 23 according to the first embodiment of the present invention are integrated. 12 is a schematic cross-sectional view showing an example of an electrode-integrated back sheet in which the metal film 12 and the back sheet 23 according to the first embodiment of the present invention are integrated, and is a cross-sectional view taken along the line IIX-IIX in FIG. FIG. By integrating the metal film 12 with the back sheet 23, it is possible to impart a back surface wiring function to the back sheet 23.

The electrode-integrated back sheet 24 shown in FIG. 11 and FIG. 12 has an adhesive layer 61 formed on one side of a pre-formed back sheet 23, and the metal film 12 is fixed to one side of the back sheet 23 via the adhesive layer 61. It is formed by. By fixing the metal film 12 to the back sheet 23 in advance, the metal film 12 and the back surface aluminum electrode 45 can be easily joined. In this case, the thickness of the adhesive layer 61 is preferably 15 μm or more and 50 μm or less. When the thickness of the adhesive layer 61 is less than 15 μm, it is difficult to handle the material constituting the adhesive layer 61. When the thickness of the adhesive layer 61 is greater than 50 μm, it becomes difficult for the adhesive layer 61 to be deformed along the metal film 12, the displacement due to thermal expansion becomes large, the back surface of the solar cell module becomes soft, and the cell due to external force Problems such as easy cracking occur.

Further, as another method for connecting the metal film 12 and the back surface aluminum electrodes 35 and 45 on the back surface of the solar battery cell 10, a method similar to the joining of the metal wire wire 11 and the grid electrodes 34 and 44 may be used. it can.

In either method using a single metal film 12 or a method using an electrode-integrated back sheet 24 in which the metal film 12 and the back sheet 23 are integrated, the plane between the back surface aluminum electrodes 35 and 45 and the metal film 12 is used. In order to connect each other, that is, the surface of the back surface aluminum electrodes 35 and 45 and the surface of the metal film 12 are connected. In this case, compared with a general tab line connection, that is, the case where the back surface aluminum electrodes 35 and 45 are connected to the tab line via the bus electrodes, the stress applied to the solar cell 10 is widely dispersed, and the solar cell The effect that the cell crack of the cell 10 hardly occurs is obtained.

In addition, when the joining area of the metal film 12 and the back surface aluminum electrodes 35 and 45 is large, the cell crack generate | occur | produces in the photovoltaic cell 10 resulting from the thermal expansion difference of the metal film 12 and the back surface aluminum electrodes 35 and 45. There is a possibility of doing. Accordingly, when the bonding area between the metal film 12 and the back surface aluminum electrodes 35 and 45 is large, the bonding between the metal film 12 and the back surface aluminum electrodes 35 and 45 is preferably a number of point connections. As an example of a large number of point connections, for example, solder paste is printed on the back surface aluminum electrodes 35 and 45 in a grid pattern at intervals of 10 mm, and the metal film 12 is connected to the back surface aluminum electrodes 35 and 45 through the solder paste.

In the case of using ACF or conductive adhesive, it is costly to apply ACF or conductive adhesive to the entire surface of the metal film 12, and the solar film is caused by the difference in thermal expansion between the metal film 12 and the back surface aluminum electrodes 35 and 45. Cell cracks may occur in the battery cell 10. For this reason, even when ACF or conductive adhesive is used, the ACF or conductive adhesive is not disposed on the entire surface of the metal film 12, and the ACF or conductive adhesive is applied with a gap in the plane of the metal film 12. It is preferable that the metal film 12 and the back surface aluminum electrodes 35 and 45 are joined partially.

Moreover, when using the pressure welding using a sealing material, although the stress concerning the metal film 12 and the back surface aluminum electrodes 35 and 45 resulting from a thermal expansion difference is small, the contact resulting from deterioration of the surface of the metal film 12 There is concern about defects. For this reason, the metal film 12 needs to select the material which does not cause the conductive defect by oxidation, such as nickel (Ni) plating copper foil, tin (Sn) plating copper foil, and silver (Ag) plating copper foil.

Even when the cross-sectional shape of the metal wire wire 11 is circular as described above, a large number of metal wires are arranged by wrapping from the surface of one of the adjacent solar cells to the back surface of the other solar cell. As a result, the inventors have clarified that a large stress is applied to the solar cell at a portion having a large curvature, and the cell is likely to be cracked. And it became clear that the cell crack of a photovoltaic cell becomes easy to generate | occur | produce by employ | adopting a multi wire system and increasing the number of wiring.

Therefore, in the solar cell module 1 according to the first embodiment, n-type solar cells 10n and p-type solar cells 10p are alternately arranged as the solar cells 10 arranged in the same row. This eliminates the need to pass the metal wire line 11 from the light receiving surface side to the back surface side between the adjacent n-type solar cell 10n and the p-type solar cell 10p, and the metal wire line 11 is not bent. The grid electrode 34 of the n-type solar cell 10n and the grid electrode 44 of the p-type solar cell 10p are connected in a straight line state.

Therefore, no stress is applied to the solar battery cell 10 due to the bending of the metal wire line 11, and cell cracking of the solar battery cell 10 due to the stress applied from the metal wire line 11 can be prevented. Further, by alternately arranging the n-type solar cells 10n and the p-type solar cells 10p, there is no need to bend the metal wire line 11 and no bus electrode is used, so that the metal wire line 11 is aligned with the bus line. Is also unnecessary, and the connecting process of the metal wire line 11 is simplified. Further, since no bus electrode is used, connection failure due to the bus electrode does not occur.

Next, a method for manufacturing the solar cell module 1 according to the first embodiment will be described. Here, a case where an electrode-integrated back sheet 24 in which the metal film 12 and the back sheet 23 are integrated will be described. First, n-type solar cells 10n and p-type solar cells 10p, which are PERC cells, are formed by a known method.

FIG. 13 is a schematic top view showing a state in which the n-type solar battery cell 10n and the p-type solar battery cell 10p according to the first embodiment of the present invention are connected by the metal wire wire 11. FIG. 14 is a schematic cross-sectional view showing a state where the n-type solar battery cell 10n and the p-type solar battery cell 10p according to the first embodiment of the present invention are connected by the metal wire wire 11, and is shown in FIG. It is sectional drawing in a XIV line. The n-type solar battery cell 10n and the p-type solar battery cell 10p are arranged adjacent to each other with the light-receiving surface side facing upward as shown in FIGS. Here, the n-type solar battery cell 10n and the p-type solar battery cell 10p have a longitudinal direction of the grid electrode 34 of the n-type solar battery cell 10n and a longitudinal direction of the grid electrode 44 of the p-type solar battery cell 10p. They are arranged in the same direction and orthogonal to the arrangement direction of the n-type solar cells 10n and the p-type solar cells 10p. Thereby, the group of the photovoltaic cell 10 is formed. Similarly, 25 sets of solar battery cells 10 are formed.

Next, the metal wire wire 11 which is the solder plating copper wire by which the surface of the copper wire with a diameter of 0.2 mm is plated is the grid electrode 34 of the n-type solar cell 10n and the grid electrode of the p-type solar cell 10p. It is arranged on the grid electrode 34 and on the grid electrode 44 in a state orthogonal to 44. And the metal wire line 11 is made into the grid electrode 34 and a grid electrode by heat-melting the solder of the surface of the metal wire line 11 pressing down the metal wire line 11 from the top so that a position shift of the metal wire line 11 may not be caused. The n-type solar cell 10n and the p-type solar cell 10p are connected by the metal wire 11 as shown in FIGS.

Next, a pressure-sensitive adhesive dissolved in a solvent is applied to the surface on the side of the sealing material 22 in the back sheet for a solar cell made of PET, and the pressure-sensitive adhesive layer 61 having a thickness of about 35 μm is formed by drying the solvent. The Then, the metal film 12 made of nickel (Ni) plated rolled copper foil is disposed on the adhesive layer 61, and the metal film 12 is bonded to the back sheet 23 by the adhesive layer 61. As a result, as shown in FIGS. 11 and 12, an electrode-integrated back sheet 24 in which the metal film 12 and the back sheet 23 are integrated is formed.

FIG. 15 is a schematic top view showing the laminate 25 before lamination according to the first embodiment of the present invention. 16 is a schematic cross-sectional view showing the laminate 25 before lamination according to the first embodiment of the present invention, and is a cross-sectional view taken along the line XVI-XVI in FIG. FIG. 15 shows a state in which the back sheet 23 and the adhesive layer 61 are seen through the electrode integrated back sheet 24. A solar cell sealing material sheet 22a made of an EVA sheet is placed on a glass substrate 21 made of white glass, which is a light-receiving surface side protection member. Next, 25 sets of solar battery cells 10 are arranged on the sheet of the sealing material 22 in an array with the metal wire 11 side facing the glass substrate 21 side. Further, the horizontal tab wire 13 and the terminal box cable for connecting to the terminal box are arranged on the sheet of the sealing material 22.

An electrode-integrated back sheet 24 is placed on the metal film 12 in accordance with the back surface aluminum electrode 35 of the n-type solar cell 10n and the back surface aluminum electrode 45 of the p-type solar cell 10p, and the laminate shown in FIGS. The previous laminate 25 is formed. Then, the laminated body 25 before lamination is thermocompression-bonded by pressurizing and heating, for example, at 150 ° C. for 30 minutes with a vacuum thermal laminator, so that the solar cell module 1 having the structure shown in FIGS. 1 to 3 is obtained. Thereafter, a terminal box (not shown) connected to the terminal box cable is disposed on the electrode-integrated back sheet 24.

As described above, in the solar cell module 1 according to the first embodiment, the n-type solar cell 10n and the p-type solar cell are arranged by alternately arranging the n-type solar cell 10n and the p-type solar cell 10p. The metal wire line 11 and the metal film 12, which are wirings for electrically connecting the battery cells 10p in series, can all be used in a straight state without bending. Thereby, the stress concerning the photovoltaic cell 10 resulting from the bending of the wiring which connects the adjacent photovoltaic cell 10 can be reduced, and the cell crack of the photovoltaic cell 10 can be prevented.

Moreover, in the solar cell module 1 concerning this Embodiment 1, in the photovoltaic cell 10, by using a multi-wire system for the connection of the n-type photovoltaic cell 10n and the p-type photovoltaic cell 10p in the light-receiving surface side. Since the effective current travel distance from the power generation position to the metal wire 11 is shortened, the electrical resistance is reduced and the photoelectric conversion efficiency of the solar cell module 1 can be improved.

Moreover, in the solar cell module 1 concerning this Embodiment 1, the surface connection by the metal film 12 which has a flat film shape for the connection of the n-type solar cell 10n and the p-type solar cell 10p in the light-receiving surface side. Therefore, the connection resistance between the metal film 12 and the back surface aluminum electrodes 35 and 45 can be lowered, and the stress applied to the solar battery cell 10 can be reduced.

Moreover, according to the solar cell module 1 concerning this Embodiment 1, while preventing the cell crack of the photovoltaic cell 10 resulting from the connection of adjacent photovoltaic cells 10, the photoelectric conversion efficiency of the photovoltaic cell 10 is improved. A solar cell module that can be improved and can improve photoelectric conversion efficiency and reliability can be obtained.

Next, description will be made based on specific examples.

Example 1.
A solar cell module was produced according to the method for manufacturing a solar cell module according to the first embodiment described above, and the solar cell module of Example 1 was obtained. As the n-type solar cell 10n and the p-type solar cell 10p, solar cells having a size of 156 mm square and a thickness of 175 μm were used. The difference in the amount of current during power generation between the n-type solar cell 10n and the p-type solar cell 10p is set to be within ± 5%. As the metal wire 11, seven solder plated copper wires having a diameter of 0.2 mm were used.

Moreover, the adhesive which melt | dissolved with the solvent is apply | coated to the surface at the side arrange | positioned at the metal film 12 side in the back sheet which consists of PET with an outer diameter of 1700 mm x 900 mm and thickness 0.2mm, and the solvent is dried. Thus, an adhesive layer 61 having a thickness of about 50 μm was formed. Then, the electrode-integrated back sheet 24 was formed by placing a Ni-plated rolled copper foil having a thickness of 0.06 mm on the adhesive layer 61. As the glass substrate, white plate glass having an outer diameter of 1600 mm × 800 mm and a thickness of 3.2 mm was used. As the sealing material sheet 22a, a sealing material sheet for solar cells made of EVA having a thickness of 0.6 mm was used.

Example 2
Except for using “six solder-plated copper wires having a diameter of 1.0 mm” instead of “seven solder-plated copper wires having a diameter of 0.2 mm” as the metal wire wires 11, the same as in Example 1. Thus, a solar cell module was produced and used as the solar cell module of Example 2.

Example 3
In Example 3, a solar cell module was produced in the same manner as in Example 1 except for the following steps, and a solar cell module of Example 3 was obtained. FIG. 17 is a schematic view of a solar cell array 62 produced by disposing the ribbon-like metal film 12 on the back surfaces of the n-type solar cell 10n and the p-type solar cell 10p in Example 3 as viewed from the back surface side. There is a bottom view. FIG. 18 is a schematic cross-sectional view of a solar cell array 62 produced by disposing the ribbon-like metal film 12 on the back surfaces of the n-type solar cell 10n and the p-type solar cell 10p in Example 3. FIG. 18 is a cross-sectional view taken along line XVIII-XVIII in FIG.

In Example 3, a set of 25 solar cells 10 connected as shown in FIG. 13 and FIG. 14 was arranged in 10 columns × 5 rows with the back side facing upward, and the horizontal tab wires 13 and terminal box cables were arranged. . As shown in FIGS. 17 and 18, a tin (Sn) plated copper foil having a width of 10 mm and a thickness of 50 μm is used as the metal film 12 on the back surface aluminum electrode 35 of the n-type solar cell 10 n and the p-type solar cell. The battery cells 10p were placed in two rows on the back surface aluminum electrode 45. An ACF 63 is disposed on one surface of the tin (Sn) plated copper foil on the solar battery cell 10 side. Then, ACF was thermocompression bonded to each tin (Sn) plated copper foil by a hot roll at a temperature at which the solder did not melt, thereby producing a solar cell array 62 of 10 columns × 5 rows as shown in FIGS. .

FIG. 19 is a schematic top view showing the laminate 64 before lamination in Example 3. 20 is a schematic cross-sectional view showing the laminate 64 before lamination in Example 3, and is a cross-sectional view taken along the line XX-XX in FIG. FIG. 21 is a schematic bottom view of the array wiring of the solar cell array of the solar cell module of Example 3 as viewed from the back surface side. 22 is a schematic cross-sectional view showing the solar cell module of Example 3, and is a cross-sectional view taken along line XXII-XXII in FIG.

On the glass substrate 21, the encapsulant sheet 22a, the solar cell array 62, the encapsulant sheet 22a, and the back sheet 23 are laminated in this order to form a laminate 64 before lamination shown in FIGS. did. Then, the laminated body 64 before lamination was thermocompression-bonded by pressurizing and heating with a vacuum thermal laminator to obtain a solar cell module of Example 3 having the structure shown in FIGS. 21 and 22.

Example 4
FIG. 23 is a schematic top view showing the laminate 66 before lamination in the fourth embodiment. 24 is a schematic cross-sectional view showing the laminated body 66 before lamination in Example 4, and is a cross-sectional view taken along line XXIV-XXIV in FIG. FIG. 25 is a schematic bottom view of the array wiring of the solar cell array of the solar cell module of Example 4 as viewed from the back side. 26 is a schematic cross-sectional view showing the solar cell module of Example 4, and is a cross-sectional view taken along line XXVI-XXVI in FIG.

In Example 4, first, in the same manner as in Example 1, n-type solar cells 10n and p-type solar cells 10p were connected by metal wire 11 to form 25 sets of solar cells 10.

Next, a solar cell sealing material sheet 22a made of a thermally crosslinkable polyolefin having a thickness of 0.8 mm and a heat softening temperature of about 60 ° C. was placed on a glass substrate 21 made of white plate glass. Next, 25 sets of solar battery cells 10 were arranged on the sheet of the sealing material 22 in an array with the metal wire 11 side facing the glass substrate 21 side. Further, the horizontal tab wire 13 and the terminal box cable for connecting to the terminal box were arranged on the sheet of the sealing material 22.

A metal film 12 made of electrolytic copper foil having a thickness of 70 μm and plated with nickel (Ni) is applied to the back surface aluminum electrode 35 of the n-type solar cell 10n and the back surface aluminum electrode 45 of the p-type solar cell 10p. It put together and joined with the horizontal tab wire | line 13 and the solder. On top of that, a laminated backsheet 65 having a two-layer structure was placed to form a laminate 66 before lamination as shown in FIGS. The laminated backsheet 65 includes an inner backsheet layer 65a made of thermoplastic polyolefin and disposed on the inner side of the solar cell module 1, and an outer backsheet layer made of polyethylene terephthalate and disposed on the outer surface side of the solar cell module 1. A laminated back sheet 65 laminated with 65b was used.

Thereafter, the laminated body 66 before lamination is subjected to thermocompression bonding by pressurizing and heating, for example, at 150 ° C. for 30 minutes with a vacuum thermal laminator, whereby the solar cell module having the structure shown in FIGS. 25 and 26 is obtained. Thereafter, a terminal box (not shown) connected to the terminal box cable was disposed on the laminated back sheet 65.

By performing lamination at 150 ° C. where the polyolefin of the inner back sheet layer 65a of the laminated back sheet 65 is softened, the sealing material sheet 22a for a solar cell made of thermally crosslinkable polyolefin having a thermal softening temperature of about 60 ° C. is melted. Then, the solar battery cell 10 is covered. On the other hand, the polyolefin of the inner backsheet layer 65a softens and exhibits adhesiveness but does not melt and flow. For this reason, the polyolefin of the inner backsheet layer 65 a does not enter between the back surface aluminum electrode 35 of the n-type solar cell 10 n and the back surface aluminum electrode 45 of the p-type solar cell 10 p and the metal film 12. Thereby, since the metal film 12 is reliably pressed against the back surface aluminum electrode 35 and the back surface aluminum electrode 45, good electrical bonding between the back surface aluminum electrode 35 and the back surface aluminum electrode 45 and the metal film 12 can be realized.

Comparative Example 1
In the comparative example 1, the p-type solar cells in which the n-type and p-type components of the above-described n-type solar cell 10n are reversed are arranged in 10 columns × 5 rows and are generally used. A battery module was produced. The p-type solar cell has an outer diameter of 156 mm square and a thickness of 175 μm, the n-type impurity diffusion layer provided on the light-receiving surface of the p-type silicon substrate is the negative electrode, and the back surface of the p-type silicon substrate is the positive electrode Has been. On the light-receiving surface side of the p-type solar cell, a plurality of grid electrodes formed by printing and baking silver paste and four bus electrodes extending in a direction perpendicular to the grid electrodes are provided. On the back surface side of the p-type solar cell, a back surface aluminum electrode is formed on the entire surface in the same manner as the n-type solar cell 10n, and four bus electrodes are formed thereon.

Adjacent p-type solar cells in the same row are soldered with four tab wires to the light receiving surface side bus electrode of one p-type solar cell and the back surface side bus electrode of the other p-type solar cell. So that they are electrically connected in series. The tab wire is a copper wire coated with solder, and is joined to the bus electrode by melting the solder. The tab line is arranged to be largely bent so as to pass from the light receiving surface side to the back surface side between adjacent p-type solar cells. In addition, the p-type solar cells at the ends of adjacent rows are electrically connected in series by horizontal tabs that are solder-coated copper wires. Thereby, all the p-type solar cells are electrically connected in series.

Comparative Example 2
Only the same p-type solar cells as in Comparative Example 1 were arranged in 10 columns × 5 rows, and an EVA sealing material having a thickness of 0.4 mm was placed on the p-type solar cells, and the thickness was further 0.2 mm. A solar cell module was produced by the multi-wire method in the same manner as in Example 1 except that the PET back sheet was placed and thermocompression bonded by pressurizing and heating with a vacuum thermal laminator.

Comparative Example 3
Similar to Comparative Example 1, except that “six solder plated copper wires with a diameter of 1.0 mm” were used as the metal wire wires 11 instead of “seven solder plated copper wires with a diameter of 0.2 mm”. Thus, a solar cell module was produced and used as a solar cell module of Comparative Example 3.

Comparative Example 4
Except for using “seven solder-plated copper wires having a diameter of 0.15 mm” instead of “seven solder-plated copper wires having a diameter of 0.2 mm” as the metal wire wires 11, the same manner as in Example 1 was used. Thus, a solar cell module was produced and used as a solar cell module of Comparative Example 4.

Comparative Example 5
Except for using “six solder-plated copper wires having a diameter of 1.5 mm” instead of “seven solder-plated copper wires having a diameter of 0.2 mm” as the metal wire wire 11, the same manner as in Example 1 was used. Thus, a solar cell module was produced and used as a solar cell module of Comparative Example 5.

(Evaluation test)
For the solar cell modules of Examples 1 to 4 and Comparative Examples 1 to 5 manufactured as described above, the initial maximum output was measured using a solar simulator. Furthermore, 1000 cycles of heat cycle tests at two temperatures of −40 ° C. and 105 ° C. were performed, and the maximum output after heat cycle of each solar cell module after the heat cycle test was measured. The measurement results of the solar cell modules of Examples 1 to 4 and Comparative Examples 1 to 5 are shown in FIG. FIG. 27 is a diagram showing the results of evaluation tests of the solar cell modules of Examples 1 to 4 and Comparative Examples 1 to 5.

The solar cell module of Example 1 does not need to pass the metal wire line 11 from the light receiving surface side to the back surface side between adjacent n-type solar cells 10n and p-type solar cells 10p, and uses bus electrodes. Therefore, alignment to the bus electrode is also unnecessary. For this reason, in the solar cell module of Example 1, the connection failure of the metal wire 11, that is, the metal wire 11 is not disconnected. Moreover, the solar cell module of Example 1 was 1.125 times the initial maximum output of the solar cell module of Comparative Example 1 by adopting the multi-wire method, and the photoelectric conversion efficiency was improved by 12.5%.

The solar cell module of Example 2 has the same configuration as that of the solar cell module of Example 1 except that the diameter and number of the metal wire wires 11 are different. For this reason, in the solar cell module of Example 2, the connection failure of the metal wire 11 is eliminated. Moreover, the solar cell module of Example 2 becomes 1.1 times the initial maximum output of the solar cell module of Comparative Example 1 by adopting the multi-wire method, similarly to the solar cell module of Example 1, and photoelectric conversion Efficiency increased by 10.0%.

The solar cell module of Example 3 employs the same multi-wire method as the solar cell module of Example 1. For this reason, in the solar cell module of Example 3, the connection failure of the metal wire 11 is eliminated. Moreover, the solar cell module of Example 3 becomes 1.125 times the initial maximum output of the solar cell module of Comparative Example 1 by adopting the multi-wire method, similarly to the solar cell module of Example 1, and photoelectric conversion Efficiency increased by 12.5%.

The solar cell module of Example 4 employs the same multi-wire method as the solar cell module of Example 1. For this reason, the solar cell module of Example 4 has lost the connection defect of the metal wire wire 11. FIG. Moreover, the solar cell module of Example 4 becomes 1.125 times the initial maximum output of the solar cell module of Comparative Example 1 by adopting the multi-wire method, similarly to the solar cell module of Example 1, and photoelectric conversion Efficiency increased by 12.5%.

As described above, the solar cell modules of Examples 1, 2, 3, and 4 have a high initial maximum output, and a decrease in the maximum output after the heat cycle is not recognized. On the other hand, in the solar cell modules of Comparative Examples 1, 2, 3, 4, and 5, a significant decrease in the maximum output was observed after the heat cycle.

The solar cell module of Comparative Example 1 had a lower initial maximum output than that of the Example adopting the multi-wire method. From this result, it can be seen that the multi-wire method is effective in improving the power generation efficiency. As a result of the analysis, the solar cell module of Comparative Example 1 is considered to have good reliability because cell cracks after the heat cycle were not observed.

Moreover, as a result of the analysis, in the solar cell modules of Comparative Example 2 and Comparative Example 3, cell cracks of the solar cell module occurred at 200 or more locations after the heat cycle, which is the main factor that the initial maximum output is low. Conceivable.

In the solar cell module of Comparative Example 4, no cell cracking of the solar cell module was observed. This is because the metal wire wire 11 is too thin and a connection failure of the metal wire wire 11 occurs, that is, the metal wire wire 11 is disconnected from the grid electrode. It is thought that the cracked cell was not generated.

Moreover, the solar cell module of the comparative example 4 is based on the analysis result of the maximum output after the heat cycle, due to poor connection between the metal wire wire 11 and the grid electrode, that is, the metal wire wire 11 is disconnected from the grid electrode. It turned out that the output has fallen. The reason why the cell crack of the solar cell module of Comparative Example 4 was not recognized is considered to be due to stress relaxation accompanying connection failure.

In the solar cell module of Comparative Example 5, the cell crack of the solar cell module remained at 50 locations, but the initial maximum output was low. As a result of the analysis, the solar cell module of Comparative Example 5 adopts the multi-wire method similarly to the solar cell module of Example 1, but because the metal wire is too thick, the sunlight incident on the solar cell is not enough. The decrease in the photoelectric conversion efficiency of the solar cells is considered to be the main factor for the low initial maximum output.

The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

1 solar cell module, 10 solar cell, 10n n-type solar cell, 10p p-type solar cell, 11 metal wire wire, 12 metal film, 13 horizontal tab wire, 21 glass substrate, 22 sealing material, 22a sealing Material sheet, 23 back sheet, 24 electrode integrated back sheet, 25, 64, 66 laminate, 31 n-type silicon layer, 32 p-type impurity diffusion layer, 33, 43, 53 depletion layer, 34, 44, 54 grid electrode , 35, 45, 55 Back surface aluminum electrode, 41 p-type silicon layer, 42 n-type impurity diffusion layer, 46 back surface passivation film, 46a contact hole, 47 alloy layer, 48 back surface electric field layer, 51 p-type silicon layer, 52 n-type Impurity diffusion layer, 56 reflective coating layer, 61 adhesive layer, 62 solar cell array Lee, 65 laminated backsheet, 65a inner backsheet layer, 65b outer backsheet layer.

Claims (10)

1. An n-type first crystalline solar cell in which the light-receiving surface side is a positive electrode;
   P-type second crystalline solar cells that are alternately arranged in parallel with the first crystalline solar cells and the light receiving surface side is a negative electrode;
   The electrodes on the light receiving surface side of the adjacent first crystal solar cells and the second crystal solar cells adjacent to each other are connected to each other and have a circular cross section whose diameter is in the range of 0.2 mm to 1.0 mm. A plurality of light-receiving surface side connection wirings made of metal wire wires made of metal or more,
   A back side connection wiring made of a metal film that connects the electrodes on the back side facing the light receiving surface side of the adjacent first crystal solar cell and the second crystal solar cell;
   A solar cell module comprising:
2. The thickness of the back side connection wiring is 0.3 mm or less,
   The solar cell module according to claim 1.
3. A back sheet is provided on the back side of the back side connection wiring,
   The back surface side connection wiring is fixed to the back sheet via an adhesive layer having a thickness of 50 μm or less,
   The solar cell module according to claim 2.
4. A light receiving surface side protection member is provided on the light receiving surface side of the light receiving surface side connection wiring,
   A back sheet is provided on the back side of the back side connection wiring,
   The first crystalline solar cell and the second, except for the electrodes on the back side of the first crystalline solar cell and the second crystalline solar cell and the junction surface of the back side connection wiring. Crystalline solar cells, the light receiving surface side connection wiring and the back surface side connection wiring are sealed with a sealing material between the light receiving surface side protection member and the back sheet,
   The back side connection wiring side in the back sheet is made of a thermoplastic resin having a higher melting point than the sealing material,
   The back surface side electrodes of the first crystal solar cell and the second crystal solar cell are in direct contact with the back surface connection wiring,
   The solar cell module according to any one of claims 1 to 3, wherein:
5. The electrode on the back side of the first crystal solar cell and the second crystal solar cell and the back side connection wiring are solder, conductive adhesive, metal paste, anisotropic conductive film or conductive Bonded with adhesive double-sided tape,
   The solar cell module according to claim 1.
6. An arrangement step of alternately arranging n-type first crystalline solar cells whose light-receiving surface side is a positive electrode and p-type second crystalline solar cells whose light-receiving surface side is a negative electrode;
   Six or more electrodes on the light-receiving surface side of the adjacent first crystal solar cells and the second crystal solar cells adjacent to each other have a circular cross section with a diameter ranging from 0.2 mm to 1.0 mm. A light-receiving surface side connection step of connecting by a plurality of light-receiving surface side connection wirings made of metal metal wires,
   A back side connection step of connecting the electrodes on the back side facing the light receiving surface side of the adjacent first crystal solar cell and the second crystal solar cell by a back side connection wiring made of a metal film;
   The manufacturing method of the solar cell module characterized by including.
7. The thickness of the back side connection wiring is 0.3 mm or less,
   The method for manufacturing a solar cell module according to claim 6.
8. Before the back side connection step, the step of fixing the back side connection wiring to one surface of the back sheet through an adhesive layer having a thickness of 50 μm or less to form an electrode integrated back sheet,
   The back surface side connection wiring is disposed in contact with electrodes on the back surface of the first crystal solar cell and the second crystal solar cell, and the first crystal solar cell and the second crystal system are arranged. Connecting the electrodes on the back side with the solar battery cell by the back side connection wiring,
   The method for manufacturing a solar cell module according to claim 7.
9. After the back side connection step,
   On the light receiving surface side protection member, the sheet of sealing material, the first crystal solar cell and the second crystal solar cell connected by the back surface side connection wiring and the light receiving surface side connection wiring, By laminating the electrode-integrated backsheet in this order, pressurizing and heating, electrodes on the back side of the first crystalline solar cell and the second crystalline solar cell, and the back side Direct contact with the connection wiring,
   The method for manufacturing a solar cell module according to claim 6, wherein:
10. In the back surface side connection step, the electrodes on the back surface side of the first crystal solar cell and the second crystal solar cell, and the back surface connection wiring, solder, conductive adhesive, metal paste, Bonding with an anisotropic conductive film or conductive double-sided tape,
    The method for manufacturing a solar cell module according to claim 6.

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