US20110197951A1

US20110197951A1 - Solar battery module and method of manufacturing the same

Info

Publication number: US20110197951A1
Application number: US13/060,193
Authority: US
Inventors: Yoshiya Abiko; Yasushi Funakoshi; Kyotaro Nakamura; Yasushi Sainoo
Original assignee: Individual
Current assignee: Sharp Corp
Priority date: 2008-08-22
Filing date: 2009-08-03
Publication date: 2011-08-18
Also published as: US20110204647A1; WO2010021235A1; JP2010050341A; US8334613B2; JP5152858B2

Abstract

A solar battery module includes a wiring substrate having connection wiring on a front surface, a plurality of solar battery cells, a sealant sealing the plurality of solar battery cells mounted on the front surface of the wiring substrate, and a light-transmitting front surface protection material covering the plurality of solar battery cells sealed with the sealant. The plurality of solar battery cells each include a cell substrate and back surface electrodes disposed on a back surface of the cell substrate. The cell substrates are arranged on the front surface of the wiring substrate. The plurality of solar battery cells are mounted on the wiring substrate by electrically connecting the back surface electrodes with the connection wiring. A filler is disposed in at least a portion of a gap between the plurality of solar battery cells.

Description

TECHNICAL FIELD

The present invention relates to a solar battery module and a method of manufacturing the same.

BACKGROUND ART

In recent years, development of clean energy has been desired because of the problem of exhaustion of energy resources, global environmental problems such as an increase in CO₂in the atmosphere, and the like. Thus, in particular, solar power generation using solar batteries has been developed, put to practical use, and is progressing as a new energy source.
Conventionally, solar batteries manufactured by forming a p-n junction by, for example, diffusing impurities having a conductivity type opposite to that of a monocrystalline or polycrystalline silicon substrate, over a light receiving surface of the silicon substrate, and forming electrodes on the light receiving surface of the silicon substrate and a back surface opposite to the light receiving surface, respectively, have been a mainstream.
In addition, the thickness of the silicon substrate has been reduced in order to reduce the cost of raw materials. There arises a problem that a reduction in the thickness of a solar battery cell (hereinafter also referred to simply as a “cell”) results in a crack in the cell during a wiring operation performed when a solar battery module (hereinafter also referred to simply as a “module”) is fabricated. To solve the problem, a method of wiring a back surface electrode type solar battery cell using a wiring substrate has been proposed. It is to be noted that the “back surface electrode type” is an antonym of a “double surface electrode type”, and refers to a type in which both a p electrode and an n electrode are formed on a back surface of a cell.
Further, improving a fill factor, that is, so-called “F. F”, of a module by using a wiring substrate has also been proposed.
However, to dispose and fix a wiring substrate within a module, a highly accurate fixing method causing no misalignment of a cell with respect to the wiring substrate before and after a manufacturing process is important. In particular, in a sealing step, since heat treatment is performed up to around 150° C., misalignment of a cell with respect to a wiring substrate is likely to occur.
On the other hand, a method of sealing and fixing cells within a resin using a sealant such as module EVA (ethylene vinyl acetate) has been known as a module structure in a conventional double surface electrode type cell or a manufacturing method thereof. This technique is disclosed, for example, in Japanese Patent Laying-Open No. 2001-119056 (Patent Document 1).
From the viewpoint of fixing cells within a module, a technique of disposing a resin having a low softening temperature at a region where a photovoltaic element is disposed and filling a resin having a high softening point in between cells, in order to prevent softening of a filler and lateral shift of a front surface protection material is proposed in Japanese Patent Laying-Open No. 2006-295087 (Patent Document 2). This technique is considered to be intended for prevention of misalignment of the front surface protection material even during outdoor use at a high temperature, by employing such a configuration.
In addition, a technique of preventing overlapping of and contact between solar battery elements by disposing a spacer between cells is disclosed in Japanese Patent Laying-Open No. 61-166182 (Patent Document 3). Further, a technique of providing a linear convex portion beforehand on a front surface of a plate-like sealant for positioning a cell string is disclosed in Japanese Patent Laying-Open No. 2005-136128 (Patent Document 4).

PRIOR ART DOCUMENTS

Patent Documents

Patent Document 1: Japanese Patent Laying-Open No. 2001-119056

Patent Document 2: Japanese Patent Laying-Open No. 2006-295087

Patent Document 3: Japanese Patent Laying-Open No. 61-166182

Patent Document 4: Japanese Patent Laying-Open No. 2005-136128

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

All of the techniques described above are based on the premise that a sealing target is a structural body in which a plurality of cells are connected in series using a metal interconnector. In this case, to seal such a structural body within a module, a resin such as an EVA (ethylene vinyl acetate) sheet is disposed on an upper surface and a lower surface of the structural body. Until the resin is cured after being subjected to heat treatment, the structural body can freely move within the liquefied resin, and a relative fixing position of the structural body with respect to a solid target can only attain an accuracy of the order of mm, at most. In addition, since these techniques are not based on the premise of using a wiring substrate, an effective effect cannot be obtained with regard to fixing of cells onto a wiring pattern on a wiring substrate and positional accuracy therebetween.
On the other hand, since accurate alignment of the order of μm is required to mount and fix cells on a wiring substrate, some new approach is needed.
Therefore, one object of the present invention is to provide a solar battery module in which solar battery cells can be aligned with high accuracy when they are mounted on a wiring substrate, and a method of manufacturing the same.

Means for Solving the Problems

To achieve the object described above, a solar battery module in accordance with the present invention includes: a wiring substrate having connection wiring on a front surface; a plurality of solar battery cells each including a cell substrate and back surface electrodes disposed on a back surface of the cell substrate, and mounted on the wiring substrate by arranging the cell substrates on the front surface of the wiring substrate and electrically connecting the back surface electrodes with the connection wiring; a sealant sealing the plurality of solar battery cells mounted on the front surface of the wiring substrate; and a light-transmitting front surface protection material covering the plurality of solar battery cells sealed with the sealant, a filler being disposed in at least a portion of a gap between the plurality of solar battery cells.

Effects of the Invention

According to the present invention, alignment and fixing of the solar battery cells onto the wiring substrate can be performed with high accuracy, and a highly efficient and high quality solar battery module and a method of manufacturing the solar battery module can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a solar battery module in Embodiment 1 in accordance with the present invention.

FIG. 2 is a partial cross sectional view of the solar battery module in Embodiment 1 in accordance with the present invention.

FIG. 3 is a partial cross sectional view focusing on one solar battery cell and the vicinity thereof included in the solar battery module in Embodiment 1 in accordance with the present invention.

FIG. 4 is an exploded view of the solar battery module in Embodiment 1 in accordance with the present invention.

FIG. 5 is a cross sectional view showing a first example of positional relationship between a wiring substrate and a filler disposed between solar battery cells.

FIG. 6 is a cross sectional view showing a second example of the positional relationship between the wiring substrate and the filler disposed between the solar battery cells.

FIG. 7 is a cross sectional view showing a third example of the positional relationship between the wiring substrate and the filler disposed between the solar battery cells.

FIG. 8 is a cross sectional view showing a fourth example of the positional relationship between the wiring substrate and the filler disposed between the solar battery cells.

FIG. 9 is a cross sectional view showing a fifth example of the positional relationship between the wiring substrate and the filler disposed between the solar battery cells.

FIG. 10 is a cross sectional view showing a sixth example of the positional relationship between the wiring substrate and the filler disposed between the solar battery cells.

FIG. 11 is a cross sectional view showing a seventh example of the positional relationship between the wiring substrate and the filler disposed between the solar battery cells.

FIG. 12 is a cross sectional view showing an eighth example of the positional relationship between the wiring substrate and the filler disposed between the solar battery cells.

FIG. 13 is a plan view showing an example in which a filler 300 is in contact with all of four side walls of a cell.

FIG. 14 is a plan view showing an example in which filler 300 is present only at a portion between cells.

FIG. 15 is a plan view showing a first example of disposition of n electrodes and p electrodes on a back surface of a silicon substrate.

FIG. 16 is a plan view showing a second example of the disposition of the n electrodes and the p electrodes on the back surface of the silicon substrate.

FIG. 17 is a plan view showing an exemplary disposition of n type wiring and p type wiring in the wiring substrate.

FIG. 18 is a plan view showing a first example of electrical connection between wiring substrates.

FIG. 19 is a plan view showing a second example of the electrical connection between the wiring substrates.

FIG. 20 is an explanatory view showing a manner of vacuum pressure bonding.

FIG. 21 is a cross sectional view of a structure subjected to the vacuum pressure bonding.

FIG. 22 is a cross sectional view of a first example of a state where a tape is applied between the cells.

FIG. 23 is a cross sectional view of a second example of the state where the tape is applied between the cells.

MODES FOR CARRYING OUT THE INVENTION

Embodiment

1

Referring to FIGS. 1 to 14, a solar battery module in Embodiment 1 in accordance with the present invention will be described. FIG. 1 shows a plan view of a solar battery module 1, and FIG. 2 shows a partial cross sectional view of solar battery module 1. As shown in FIG. 1, solar battery module 1 has a structure in which a plurality of solar battery cells 100 are arranged in an array on a front surface of one wiring substrate 200. Further, FIG. 3 shows a partial cross sectional view focusing on one solar battery cell 100 and the vicinity thereof. In FIG. 3, solar battery cells adjacent on both sides, a filler, and a sealant 400 are not shown.
Solar battery module 1 in the present embodiment includes wiring substrate 200 having connection wiring on the front surface, the plurality of solar battery cells 100, sealant 400 sealing the plurality of solar battery cells 100 mounted on the front surface of the wiring substrate, and a light-transmitting front surface protection material 500 covering the plurality of solar battery cells 100 sealed with sealant 400. The plurality of solar battery cells 100 each include a cell substrate 120 and back surface electrodes disposed on a back surface of cell substrate 120. The back surface electrodes include two types of electrodes, that is, an n electrode 106 and a p electrode 107. In the present embodiment, n electrodes 106 and p electrodes 107 are alternately arranged. Cell substrates 120 are arranged on the front surface of wiring substrate 200. The plurality of solar battery cells 100 are mounted on wiring substrate 200 by electrically connecting the back surface electrodes with the connection wiring. A filler 300 is disposed in at least a portion of a gap between the plurality of solar battery cells 100.
As shown in FIG. 3, an upper surface of a silicon substrate 101 of solar battery cell 100 is a light receiving surface, that is, a surface on which sunlight is incident, and an anti-reflection film 102 is provided on this surface. On the other hand, in the vicinity of a lower surface of silicon substrate 101, n-type impurity-doped regions 104 formed by diffusing n-type impurities and p-type impurity-doped regions 105 formed by diffusing p-type impurities are provided to be alternately arranged at a predetermined spacing. The lower surface of silicon substrate 101 is covered with a passivation film 103. N electrode 106 and p electrode 107 are formed to come into contact with n-type impurity-doped region 104 and p-type impurity-doped region 105, respectively, through contact holes formed in passivation film 103.
The connection wiring on the front surface of wiring substrate 200 includes two types of wiring, that is, n type wiring 109 and p type wiring 110. Wiring substrate 200 includes an insulating substrate 111, n type wiring 109, and p type wiring 110. N electrode 106 of solar battery cell 100 is electrically connected with n type wiring 109 of wiring substrate 200, and p electrode 107 is electrically connected with p type wiring 110 of wiring substrate 200.
FIG. 4 shows an exploded view of the solar battery module. A solar battery cell 100 i and another adjacent solar battery cell 100 j are mounted on the front surface of wiring substrate 200. Although many solar battery cells are actually arranged within the solar battery module, a description will now be given, focusing on two solar battery cells 100 i and 100 j, as a typical example.
To fix planar positions of solar battery cells 100 i, 100 j on the front surface of wiring substrate 200, filler 300 is disposed in a gap between solar battery cells 100 i and 100 j. Sealant 400 covers these plural cells from above. Further, light-transmitting front surface protection material 500 covers an upper side of sealant 400. Although sealant 400 is actually once liquefied, enters into a gap, and then is cured to seal the solar battery cells, it is schematically illustrated in this exploded view (FIG. 4) as a flat plate-like material before use.
The solar battery module in the present embodiment can have high quality because alignment and fixing of the solar battery cells onto the wiring substrate can be performed with high accuracy.
FIGS. 5 to 12 show several examples of positional relationship between wiring substrate 200 and filler 300 disposed between solar battery cells 100 i and 100 j. FIGS. 5 to 12 provide enlarged views, focusing on the gap between the solar battery cells.
As the solar battery module in the present embodiment, it is preferable that filler 300 is disposed to be in contact with wiring substrate 200 at a bottom portion of the gap. Specifically, it is preferable that filler 300 extends downward to an extent that filler 300 comes into contact with insulating substrate 111 of wiring substrate 200, as in the examples shown in FIGS. 6 to 11. The reason for that is because, with this structure, relative positional relationship between a metal wiring pattern bonded and fixed onto wiring substrate 200 and the solar battery cells can be fixed more firmly before and after heat treatment in a sealing step, and alignment thereof in the relative positional relationship can be performed with high accuracy.
As the solar battery module in the present embodiment, it is preferable that filler 300 is distributed in a range wider than the gap by extending to enter into a space between cell substrate 120 and wiring substrate 200. Specifically, it is preferable that filler 300 extends as in the examples shown in FIGS. 7 to 11. The reason for that is because, with this structure, bond strength between cell substrate 120 and wiring substrate 200 is further increased.
However, even when filler 300 is not in contact with wiring substrate 200 throughout the gap, and there are locally some places having a structure as shown in FIG. 5 or 12, a tolerable effect as the present invention can be exhibited.
In FIG. 5, although filler 300 is disposed in the gap, filler 300 does not abut on wiring substrate 200. An upper end of filler 300 is flush with an upper surface of cell substrate 120. In FIG. 6, although filler 300 reaches wiring substrate 200, filler 300 does not enter into a void on a back side of cell substrate 120. In FIG. 7, filler 300 also enters into the void on the back side of cell substrate 120, and filler 300 is in contact with insulating substrate 111 of wiring substrate 200 in a range wider than the gap between the solar battery cells. Although the most preferable example of the three examples shown in FIGS. 5 to 7 is the example shown in FIG. 7, a portion in a state as shown in FIG. 5 may be locally present. In FIG. 8, although filler 300 enters into the void on the back side of cell substrate 120, the upper end of filler 300 is lower than the upper surface of cell substrate 120. In FIG. 9, filler 300 enters into the void on the back side of cell substrate 120, and the upper end of filler 300 slightly bulges at the upper surface of cell substrate 120. However, the bulge has a height comparable to that of the highest portion of asperities on a front surface of anti-reflection film 102.
It is preferable that the filler protrudes at an upper portion of the gap to be higher than the upper surface of the cell substrate. In FIG. 10, filler 300 protrudes from the upper surface of cell substrate 120, and further moves onto the front surface of anti-reflection film 102 and extends to both sides.
Although the most preferable example of the three examples shown in FIGS. 8 to 10 is the example shown in FIG. 9 or 10, a tolerable effect can be exhibited even when a portion in a state as shown in FIG. 8 is locally present. If filler 300 has a structure moving onto the upper surface of cell substrate 120 and extending as shown in FIG. 10, it is desirable that filler 300 is transparent.
Even when filler 300 protrudes from the upper surface of cell substrate 120, filler 300 preferably protrudes from the upper surface of cell substrate 120 without blocking the light receiving surface, that is, without overlying the upper surface of cell substrate 120, as shown in FIG. 11. It is to be noted, however, that the height of a portion of filler 300 protruding from an upper surface of the solar battery cell should not exceed the thickness of the sealant applied later, because a protruding portion exceeding the thickness of the sealant may penetrate the sealant and damage sealing with the sealant.
In the example shown in FIG. 12, the upper end of filler 300 is lower than the upper surface of the solar battery cell, and a lower end of filler 300 does not reach wiring substrate 200. A portion in such a state may be locally present.
Insulating substrate 111 included in wiring substrate 200 may be of the same material as sealant 400.
FIGS. 13 and 14 show only a region corresponding to two cells extracted from the solar battery module, when seen from above, in order to describe positional relationship between the solar battery cell and the filler. Although solar battery cells 100 i and 100 j are extracted and shown in these figures as an example, and the number of the cells is two, the number of the cells is naturally not limited to this number in an actual structure. The form as shown in FIG. 13 in which filler 300 is in contact with all of four side walls of a cell is desirable. Specifically, it is preferable that the filler is disposed to fill the gap entirely. However, since comparable alignment accuracy can be obtained even in a case where filler 300 is present only at a portion between the cells as shown in FIG. 14, such a case is included in the present invention.
Preferably, in the solar battery module in the present embodiment, filler 300 is a resin, because, if filler 300 is a resin, reduction in cost and weight can be achieved. Further, if filler 300 is a resin, a process can proceed at a low temperature, which is advantageous. A resin more excellent in weather resistance than the sealant is desirable, if possible. Specifically, as the resin, for example, if an EVA (ethylene vinyl acetate) sheet commonly used as a sealant for a solar battery module is utilized, the same EVA resin may be used. Further, as the resin, a resin such as an acrylic resin, an epoxy resin, a urethane resin, and a silicone resin is preferable. In addition, any resin such as an olefin resin, a polyester resin, a polystyrene resin, a polycarbonate resin, a polyethylene resin, a polypropylene resin, a polyethylene terephthalate (PET) resin, a polyethylene naphthalate resin, a polysulfone resin, a polyphenylenefide resin, a polyethersulfone resin, a polyetherimide resin, a polyimide resin, and a rubber resin may be used.
Specifically, it is preferable that the filler includes at least one resin selected from the group consisting of ethylene vinyl acetate, an epoxy resin, an acrylic resin, a urethane resin, an olefin resin, a polyester resin, a silicone resin, a polystyrene resin, a polycarbonate resin, a polyethylene resin, a polypropylene resin, a polyethylene terephthalate (PET) resin, a polyethylene naphthalate resin, a polysulfone resin, a polyphenylenefide resin, a polyethersulfone resin, a polyetherimide resin, a polyimide resin, and a rubber resin.
These resins can be in a solid, liquid, or amorphous state. In the case of a solid resin, a tape-like resin is common in form, and the solid resin may take the form of a film, a bar, or the like. A resin that is a liquid at ordinary temperature, or a resin that is a solid in an initial state but is once liquefied in a certain step, and then is cured and becomes solid when the module is finally completed, is desirable to eliminate a void and achieve highly air tight sealing, that is, highly reliable sealing. Specifically, for example, if a thermoplastic resin or a thermosetting resin is used, heat may be locally applied before sealing to cure the resin to prevent movement of the solar battery cells, and then the entire region of the filler may be cured in a heat treatment step during sealing. Alternatively, if a UV curable resin is used, the resin may be cured in a UV irradiation step. Further alternatively, if a two-component curable resin or ordinary temperature setting resin is used, the resin may be cured only by being kept at ordinary temperature.
In addition, in the present embodiment, it is desirable that aligned solar battery cells are disposed beforehand, prior to application of the filler. This can reliably fill a void and suppress inclusion of bubbles and the like, and can further ensure a fixing force.

Embodiment 2

A method of manufacturing a solar battery module in Embodiment 2 in accordance with the present invention will be described. The method of manufacturing a solar battery module in the present embodiment includes the steps of arranging and fixing a plurality of solar battery cells each including a cell substrate and back surface electrodes disposed on a back surface of the cell substrate, on a front surface of a wiring substrate having connection wiring on the front surface, applying a filler to a gap between the solar battery cells arranged on the front surface of the wiring substrate, and sealing the plurality of solar battery cells arranged on the front surface of the wiring substrate with a sealant after the step of applying the filler.
Preferably, in the step of applying the filler, the filler is also applied to outer peripheral portions of the plurality of solar battery cells arranged on the front surface of the wiring substrate.
According to the method of manufacturing a solar battery module in the present embodiment, alignment and fixing of the solar battery cells onto the wiring substrate can be performed with high accuracy, and a method of manufacturing a highly efficient and high quality solar battery module can be provided.
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited thereto.

EXAMPLE 1

As Example 1, a case where metal electrodes are connected with solder will be described.
Firstly, back surface junction type solar battery cell 100 in the form shown in FIG. 3 was prepared. Here, the light receiving surface and the back surface of silicon substrate 101 of solar battery cell 100 are each in the shape of a pseudo-square with each side measuring 126 mm. FIG. 15 shows the back surface of silicon substrate 101. On the back surface of silicon substrate 101, n electrodes 106 and p electrodes 107 were alternately arranged in parallel as linear patterns.
Alternatively, n electrodes 106 and p electrodes 107 may be alternately arranged as dot patterns as shown in FIG. 16. Using the dot patterns as shown in FIG. 16 is preferable, because a wider area can be covered with the passivation film, and high output can be obtained. Further, silicon substrate 101 may have a thickness of around 100 to 500 μm, and the thickness of silicon substrate 101 is set to 200 μm in the present example. However, according to the present invention, the thickness can be reduced to not more than 100 μm.
Next, as shown in FIG. 17, insulating substrate 111 made of a PET (polyethylene terephthalate) film was prepared, and n type wiring 109 and p type wiring 110 made of copper were transferred onto insulating substrate 111 to fabricate wiring substrate 200. Electrical connection between wiring substrates 200 as shown in FIG. 17 may be established by forming a pattern electrode beforehand as shown in FIG. 18, or by welding a bus bar electrode 201 or the like as shown in FIG. 19. The number of cells connected in series and disposition thereof can be arbitrarily selected. Here, wiring substrate 200 had a wiring pattern that allows a total of 16 solar battery cells 100 arranged in a four-by-four array to be electrically connected in series as shown in FIG. 18 or 19.
Subsequently, solder paste or molten solder is formed by patterning on surfaces of n electrodes 106 and p electrodes 107 on the back surface of the solar battery cell. Alternatively, solder paste or molten solder may be formed by patterning on front surfaces of n type wiring 109 and p type wiring 110 of wiring substrate 200, instead of n electrodes 106 and p electrodes 107. Further alternatively, solder paste or molten solder may be formed by patterning on both of the surfaces of n electrodes 106 and p electrodes 107 on the back surface of the solar battery cell and the front surfaces of n type wiring 109 and p type wiring 110 of wiring substrate 200. For the patterning thereof, a screen printing method, an ink jet method, a dip soldering method, or the like can be used.
Thereafter, as shown in FIG. 18 or 19, solar battery cells 100 are placed on wiring substrate 200. The placement is performed by aligning solar battery cells 100 using alignment marks formed on solar battery cells 100 beforehand. Thereby, a solar battery in which solar battery cells 100 were placed on wiring substrate 200 as shown in FIG. 3 was fabricated. In the solar battery, n electrode 106 of solar battery cell 100 is placed on n type wiring 109 of wiring substrate 200, and p electrode 107 of solar battery cell 100 is placed on p type wiring 110 of wiring substrate 200. The “placement” used herein refers to a state in which an electrode is merely located and not joined. Hereinafter, the term “placement” refers to the same state.
Thereafter, the temperature was increased to a temperature required to melt solder, that is, around 130 to 200° C., to melt solder at an interface 113 between n and p electrodes 106, 107 of the cells and n and p type wiring 109, 110, to establish electrical connection between solar battery cells 100 and wiring substrate 200 and fix the positions thereof.
After the plurality of solar battery cells 100 are disposed in a matrix and fixed on wiring substrate 200 as shown in FIG. 18 or 19, filler 300 was applied to the gap between the cells and cell edge portions corresponding to an outer peripheral portion of the wiring substrate. As an application method, automatic application using a dispenser or a spray is preferable.
Next, although the process may directly proceed to the sealing step, it is preferable to cure and solidify at least a portion of filler 300. If a UV curable resin is used as the filler, it is preferable to irradiate a corresponding portion with ultraviolet rays on this occasion to cure the portion. If a thermosetting resin is used, it is preferable to locally apply heat and then perform regular curing with the heat used in the sealing step.
Subsequently, as shown in FIG. 20, light-transmitting front surface protection material 500 made of glass, a first transparent resin 400 a made of an ethylene vinyl acetate resin, the solar battery fabricated as described above, a second transparent resin 400 b made of an ethylene vinyl acetate resin, and a protection sheet 600 were introduced into a laminator in this order to perform vacuum pressure bonding between the first transparent resin 400 a and the second transparent resin 400 b. Here, as protection sheet 600, an aluminum foil sandwiched by PET films was used. Further, the vacuum pressure bonding was performed by keeping the materials at 125° C. for five minutes in an evacuated state.
Then, after the vacuum pressure bonding, the first transparent resin 400 a and the second transparent resin 400 b were melted by heating the materials at 135° C. for 40 minutes. Further, the materials were cooled to cure the melted transparent resins, and thereby the materials were integrated as shown in FIG. 21. By the curing, sealant 400 was formed, and at the same time solar battery cells 100 were pressure bonded to wiring substrate 200 by a fixing strength of sealant 400. Through the steps described above, a structure in which the solar battery having solar battery cells 100 placed on wiring substrate 200 was sealed within sealant 400, that is, solar battery module 1, was completed.

EXAMPLE 2

As Example 2, a case where metal electrodes are connected with a conductive adhesive material will be described. The process up to the step of preparing solar battery cell 100 and wiring substrate 200 is the same as that in Example 1.
Subsequently, a conductive adhesive or an anisotropically conductive adhesive paste (ACP) is applied, or an anisotropically conductive adhesive film (ACF) or the like is disposed, on the surfaces of n electrodes 106 and p electrodes 107 on the back surface of the solar battery cell. Alternatively, the above materials may be applied or disposed on the front surfaces of n type wiring 109 and p type wiring 110 of wiring substrate 200, instead of n electrodes 106 and p electrodes 107. Further alternatively, the above materials may be applied or disposed on both of the surfaces of n electrodes 106 and p electrodes 107 on the back surface of the solar battery cell and the front surfaces of n type wiring 109 and p type wiring 110 of wiring substrate 200.
If the adhesive or ACP is used, it may be entirely applied, and it may also be selectively applied by patterning only on the surfaces of the electrodes. For the application and patterning thereof, the screen printing method, the ink jet method, an application method using a cloth impregnated with the adhesive or ACP, or the like can be used.
Thereafter, as shown in FIG. 18 or 19, solar battery cells 100 are placed on wiring substrate 200, as described in Example 1. The placement is performed by aligning solar battery cells 100 using alignment marks formed on solar battery cells 100 beforehand. Thereby, a solar battery in which solar battery cells 100 were placed on wiring substrate 200 as shown in FIG. 3 was fabricated. In the solar battery, n electrode 106 of solar battery cell 100 is placed on n type wiring 109 of wiring substrate 200, and p electrode 107 of solar battery cell 100 is placed on p type wiring 110 of wiring substrate 200. The “placement” used herein refers to a state in which an electrode is merely located and not joined.
On this occasion, various methods can be employed as a method of fixing solar battery cells 100 at predetermined positions on wiring substrate 200. For example, solar battery cells 100 may be fixed by applying a transparent UV curable resin in a small amount from a front surface side to overlie cell edges and wiring substrate 200, and curing the resin by ultraviolet irradiation. Alternatively, solar battery cells 100 may be fixed by applying a light-transmitting tape from the front surface side. Further alternatively, if a thermosetting conductive adhesive is used, solar battery cells 100 may be fixed using an adhesive force before curing with no change, and may be temporarily fixed by locally applying heat to cure the adhesive.
After the plurality of solar battery cells 100 are disposed in a matrix and fixed on wiring substrate 200 as shown in FIG. 18 or 19, filler 300 is applied to the gap between the cells and the cell edge portions corresponding to the outer peripheral portion of the wiring substrate. As an application method, automatic application using a dispenser or a spray is preferable.
The subsequent step is the same as that described in Example 1. Specifically, vacuum pressure bonding was performed as shown in FIGS. 20 and 21 to complete a solar battery module. It is to be noted that, also when the ACP or ACF was used, sufficient electrical connection was obtained by a pressure bonding force during the vacuum pressure bonding.

EXAMPLE 3

As Example 3, a case where an adhesive is applied between pattern electrodes will be described. The process up to the step of preparing solar battery cell 100 and wiring substrate 200 is the same as that in Example 1.
Subsequently, an adhesive is applied to a region between n electrode 106 and p electrode 107 on the back surface of solar battery cell 100. Alternatively, an adhesive is applied to a region between n type wiring 109 and p type wiring 110 on the front surface of wiring substrate 200. Further alternatively, an adhesive may be applied to both of the region between n electrode 106 and p electrode 107 on the back surface of solar battery cell 100 and the region between n type wiring 109 and p type wiring 110 on the front surface of wiring substrate 200. The application of an adhesive is performed to form an adhesive layer to be limited to a desired pattern only, and the screen printing method, the ink jet method, or the like can be used. In addition, instead of applying an adhesive in a desired pattern only from the beginning, it is also effective to screen an adhesive once entirely applied, by pressing a scraper or the like against the front surface to scrape the adhesive off, that is, to remove an unnecessary adhesive remaining on the electrodes. In this case, although a slight amount of adhesive may fail to be removed and remain on n and p electrodes 106, 107 of the cell or wiring substrate 200, a small amount of adhesive may remain as long as it does not interrupt electrical contact. Instead of pressing a scraper or the like against the front surface to scrape the adhesive off, screening may be performed by squeezing out an excess adhesive between n electrode 106 and p electrode 107 of the cell and between respective electrodes of n and p type wiring 109, 110, by pressing only, without scraping the adhesive off.
Thereafter, as shown in FIG. 18 or 19, solar battery cells 100 are placed on wiring substrate 200, as described in Example 1. The placement was performed by aligning solar battery cells 100 using alignment marks formed on solar battery cells 100 beforehand.
Thereby, a solar battery in which solar battery cells 100 were placed on wiring substrate 200 as shown in FIG. 3 was fabricated. The subsequent step is the same as that described in Example 1. Specifically, vacuum pressure bonding was performed as shown in FIGS. 20 and 21 to complete a solar battery module.

EXAMPLE 4

As Example 4, a case where a solar battery cell is temporarily fixed using an adhesive material partially on the back surface of the cell will be described. The process up to the step of preparing solar battery cell 100 and wiring substrate 200 is the same as that in Example 1.
Subsequently, an adhesive was applied to at least one of the back surface of solar battery cell 100 and a portion of the front surface of wiring substrate 200. The adhesive may be applied in an amount that is enough to prevent misalignment of solar battery cell 100 with respect to wiring substrate 200 and cause no problem in electrical contact. With this method, patterning is not required and thus the number of steps can be reduced. In addition, since only a small amount of the adhesive is used, material cost can also be reduced.
Thereafter, as shown in FIG. 18 or 19, solar battery cells 100 are placed on wiring substrate 200. The placement was performed by aligning solar battery cells 100 using alignment marks formed on solar battery cells 100 beforehand.
Thereby, a solar battery in which solar battery cells 100 were placed on wiring substrate 200 as shown in FIG. 3 was fabricated. The subsequent step is the same as that described in Example 1. Specifically, vacuum pressure bonding was performed as shown in FIGS. 20 and 21 to complete a solar battery module.

EXAMPLE 5

As Example 5, a case where the filler is also used to temporarily fix cells will be described. In this case, no adhesive is used.
The process up to the step of preparing solar battery cell 100 and wiring substrate 200 is the same as that in Example 1. Subsequently, filler 300 is applied to the gap between the cells and the cell edge portions corresponding to the outer peripheral portion of the wiring substrate. It is desirable to apply filler 300 such that only a small portion of filler 300 overlies a region where cells 100 are disposed. As an application method, automatic application using a dispenser or a spray is preferable.
Thereafter, as shown in FIG. 18 or 19, solar battery cells 100 are placed on wiring substrate 200. The placement was performed by aligning solar battery cells 100 using alignment marks formed on solar battery cells 100 beforehand. Thereby, a solar battery in which solar battery cells 100 were placed on wiring substrate 200 as shown in FIG. 3 was fabricated. In the solar battery, n electrode 106 of solar battery cell 100 is placed on n type wiring 109 of wiring substrate 200, and p electrode 107 of solar battery cell 100 is placed on p type wiring 110 of wiring substrate 200.
On this occasion, at least a portion of filler 300 was cured to fix solar battery cells 100. If a UV curable resin is used as the filler, it is preferable to irradiate a corresponding portion with ultraviolet rays on this occasion to cure the portion. If a thermosetting resin is used, it is preferable to locally apply heat and then perform regular curing with the heat used in the sealing step.
The subsequent step is the same as that described in Example 1. Specifically, vacuum pressure bonding was performed as shown in FIGS. 20 and 21 to complete a solar battery module.

EXAMPLE 6

As Example 6, a case where the filler is in the form of a tape will be described.
The process up to the step of preparing solar battery cell 100 and wiring substrate 200 is the same as that in Example 1. As shown in FIG. 18 or 19, solar battery cells 100 are placed on wiring substrate 200, as described in Example 1. The placement was performed by aligning solar battery cells 100 using alignment marks formed on solar battery cells 100 beforehand. Thereby, a solar battery in which solar battery cells 100 were placed on wiring substrate 200 as shown in FIG. 3 was fabricated.
In the solar battery, n electrode 106 of solar battery cell 100 is placed on n type wiring 109 of wiring substrate 200, and p electrode 107 of solar battery cell 100 is placed on p type wiring 110 of wiring substrate 200.
In this state, a light-transmitting tape as filler 300 is applied to the gap between the cells and the cell edge portions corresponding to the outer peripheral portion of wiring substrate 200. Any tape having a high light transmitting property may be applied, including, for example, a cellophane adhesive tape, a PET tape, and a Teflon (registered trademark) tape. When the tape is applied, attention should be paid to ensure that the tape adheres to both solar battery cells 100 and wiring substrate 200, in at least a portion thereof. The tape is applied, for example, as shown in FIGS. 22 and 23. FIGS. 22 and 23 are each a cross sectional view of a state where the tape is applied between the cells.
The subsequent step is the same as that described in Example 1. Specifically, vacuum pressure bonding was performed as shown in FIGS. 20 and 21 to complete a solar battery module.

EXAMPLE 7

As Example 7, a case where the filler is a solid resin will be described. The process up to the step of preparing solar battery cell 100 and wiring substrate 200 is the same as that in Example 1.
Subsequently, an adhesive was applied to at least one of the back surface of solar battery cell 100 and a small portion of the front surface of wiring substrate 200. The adhesive may be applied in an amount that is enough to prevent misalignment of solar battery cell 100 with respect to wiring substrate 200 and cause no problem in electrical contact. With this method, patterning is not required and thus the number of steps can be reduced. In addition, since only a small amount of the adhesive is used, material cost can also be reduced.
Thereafter, as shown in FIG. 18 or 19, solar battery cells 100 are placed on wiring substrate 200. The placement was performed by aligning solar battery cells 100 using alignment marks formed on solar battery cells 100 beforehand. Thereby, a solar battery in which solar battery cells 100 were placed on wiring substrate 200 as shown in FIG. 3 was fabricated. In the solar battery, n electrode 106 of solar battery cell 100 is placed on n type wiring 109 of wiring substrate 200, and p electrode 107 of solar battery cell 100 is placed on p type wiring 110 of wiring substrate 200.
On this occasion, as a method of fixing solar battery cells 100 at predetermined positions on wiring substrate 200, an adhesive force of the adhesive before curing may be used with no change, a transparent UV curable resin may be applied to a portion of the front surfaces of cells 100 and cured by ultraviolet irradiation to fix cells 100, or a light-transmitting tape may be used. If a thermosetting adhesive is applied to the back surfaces of cells 100 or the front surface of wiring substrate 200, cells 100 may be temporarily fixed by locally applying heat to corresponding portions.
After solar battery cells 100 were disposed in a matrix and fixed on wiring substrate 200 as shown in FIG. 18 or 19, filler 300 made of a solid resin was disposed at the gap between solar battery cells 100 and the cell edge portions adjacent to the outer peripheral portion of wiring substrate 200. Here, as the filler, a thermoplastic resin such as an ethyl vinyl acetate resin, a thermosetting resin such as an olefin resin, a silicone resin, and an epoxy resin, or a resin that is solid at ordinary temperature such as a urethane resin and a rubber resin molded to have a predetermined size, was used.
The subsequent step is the same as that described in Example 1. Specifically, vacuum pressure bonding was performed as shown in FIGS. 20 and 21 to complete a solar battery module.
Preferably, in the solar battery module in accordance with the present invention, the filler is colored. For example, if the filler is colored in a color at the time of sealing the cells, design property is improved. In addition, it is preferable that the filler has a color having a property of reflecting light within a spectral sensitivity wavelength of the solar battery cell, or that the filler has a color having a light reflection property. If the filler has such a color, light once reflected at an area thereof is incident again on the cell, causing an improvement in a short circuit current value and an increase in electrical output.
Even when the filler has a color having a property of reflecting light outside the spectral sensitivity wavelength of the solar battery cell, each color has an effect. For example, if the color has a property of reflecting ultraviolet light of not more than 300 nm, weather resistance is improved. For example, if the color has a property of reflecting light having a wavelength of infrared light or higher than that, rise in temperature of a solar power generation panel can be prevented, and properties during actual operation can be improved.
Alternatively, in some cases, it is preferable that the filler has a color similar to that of the cell substrate, because this can make the filler less noticeable and overall unity in appearance can be provided.
It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the scope of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the scope of the claims.

INDUSTRIAL APPLICABILITY

The present invention is applicable to a solar battery module and a method of manufacturing the same.

DESCRIPTION OF THE REFERENCE SIGNS

1: solar battery module, 100, 100 i, 100 j: solar battery cell, 101: silicon substrate, 102: anti-reflection film, 103: passivation film, 104: n-type impurity-doped region, 105: p-type impurity-doped region, 106: n electrode, 107: p electrode, 109: n type wiring, 110: p type wiring, 111: insulating substrate, 112: void, 113: interface, 120: cell substrate, 200: wiring substrate, 201: bus bar electrode, 300: filler, 400: sealant, 400 a: first transparent resin, 400 b: second transparent resin, 500: light-transmitting front surface protection material, 600: protection sheet.

Claims

1. A solar battery module, comprising:

a wiring substrate having connection wiring on a front surface;

a plurality of solar battery cells each including a cell substrate and back surface electrodes disposed on a back surface of said cell substrate, and mounted on said wiring substrate by arranging said cell substrates on the front surface of said wiring substrate and electrically connecting said back surface electrodes with said connection wiring;

a light-transmitting front surface protection material covering said plurality of solar battery cells; and

a sealant provided between said light-transmitting front surface protection material and said wiring substrate for sealing said plurality of solar battery cells mounted on the front surface of said wiring substrate,

a filler being disposed in at least a portion of a gap between said plurality of solar battery cells, to extend across said gap.

2. The solar battery module according to claim 1, wherein said filler is disposed to be in contact with said wiring substrate at a bottom portion of said gap.

3. The solar battery module according to claim 2, wherein said filler is distributed in a range wider than said gap by extending to enter into a space between said cell substrate and said wiring substrate.

4. The solar battery module according to claim 1, wherein said filler is disposed to fill said gap entirely.

5. The solar battery module according to claim 1, wherein said filler protrudes at an upper portion of said gap to be higher than an upper surface of said cell substrate.

6. The solar battery module according to claim 1, wherein said filler is colored.

7. The solar battery module according to claim 1, wherein said filler has a color having a property of reflecting light within a spectral sensitivity wavelength of said solar battery cell.

8. The solar battery module according to claim 1, wherein said filler has a color having a light reflection property.

9. The solar battery module according to claim 1, wherein said filler has a color similar to that of said cell substrate.

10. The solar battery module according to claim 1, wherein said filler is a resin.

11. The solar battery module according to claim 10, wherein said filler includes at least one resin selected from the group consisting of ethylene vinyl acetate, an epoxy resin, an acrylic resin, a urethane resin, an olefin resin, a polyester resin, a silicone resin, a polystyrene resin, a polycarbonate resin, a polyethylene resin, a polypropylene resin, a polyethylene terephthalate (PET) resin, a polyethylene naphthalate resin, a polysulfone resin, a polyphenylenefide resin, a polyethersulfone resin, a polyetherimide resin, a polyimide resin, and a rubber resin.

12. The solar battery module according to claim 1, wherein said filler is a tape-like material.

13. A method of manufacturing a solar battery module, comprising the steps of:

arranging and fixing a plurality of solar battery cells each including a cell substrate and back surface electrodes disposed on a back surface of said cell substrate, on a front surface of a wiring substrate having connection wiring on the front surface;

disposing a filler in a gap between said solar battery cells arranged on the front surface of said wiring substrate, to extend across said gap; and

sealing said plurality of solar battery cells arranged on the front surface of said wiring substrate and said filler with a sealant after the step of disposing said filler.

14. The method of manufacturing a solar battery module according to claim 13, wherein, in the step of disposing said filler, said filler is also disposed in outer peripheral portions of said plurality of solar battery cells arranged on the front surface of said wiring substrate.