JPWO2018142544A1 - Solar cell module and method of manufacturing the same - Google Patents

Abstract

The solar cell module (1) is a p-type first solar cell whose n-type first crystal solar cell whose light receiving surface side is a positive electrode and a first crystal solar cell alternately arranged in parallel and whose light receiving surface side is a negative electrode And a two-crystal solar cell. Further, the solar cell module (1) connects the electrodes on the light receiving surface side of the adjacent first crystal solar cell and the second crystal solar cell, and the diameter is in the range of 0.2 mm to 1.0 mm. Between a plurality of light-receiving surface side connection wires composed of six or more metallic metal wire wires (11) having a circular cross section, and the adjacent first crystal solar cell and second crystal solar cell And a back surface side connection wiring made of a metal film (12) connecting electrodes on the back surface side facing the light receiving surface side.

Description

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

  Currently, the warranty period of solar cell modules has been extended to about 25 years. A solar cell module is required to have high reliability and high photoelectric conversion efficiency. The most frequent deterioration of the solar cell module is the disconnection of the connection between the solar cells. It is known that the main causes of the disconnection failure are a defect in the connection and a tab wire disconnection failure. The broken tab line defect is due to fatigue of the tab line, and in particular, the large curvature is disposed around the surface of one of the adjacent solar cells to the back of the other solar cell. It is easy to occur in parts.

  On the other hand, solar cells different in polarity are alternately arranged, that is, p-type solar cells and n-type solar cells are alternately arranged, and the solar cells from the surface of one solar cell to the other are arranged. It is known that it is possible to eliminate the wraparound of the tab line on the back of the cell. In Patent Document 1, an n-type solar cell using an n-type silicon substrate with the light receiving surface as the positive electrode and a back surface as the negative electrode, and a p-type silicon substrate with the light receiving surface as the negative electrode and the back surface as the positive electrode A solar cell module is disclosed in which p-type solar cells are alternately arranged. 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 by the surface side connection tab made of a metal wire. Moreover, the bus-bar electrode parts of the back surface side of adjacent photovoltaic cells are connected by the back surface side connection tab which consists of stripe-shaped 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 adjacent solar cells are connected by the front side connection tab made of a metallic ribbon, and the back side of the adjacent solar cells The bus bar electrode portions are connected to each other by a back side connection tab made of a strip-like metal foil. That is, since the adjacent solar cells are connected via the bus electrode and the connection tab, a large improvement in the photoelectric conversion efficiency can not be expected. In addition, since the number of front side connection tabs is smaller than the number of back side connection tabs, the number of front side connection tabs is small on the front side, so the effective current transfer from the current source to the front side connection tabs Since the distance is increased, the electrical resistance is increased, and a large improvement in photoelectric conversion efficiency can not be expected.

  On the other hand, as a method for achieving high photoelectric conversion efficiency of a solar cell module, a multi-wire system in which a large number of metal wire wires are directly joined to grid electrodes on solar cells without using bus bar electrodes has attracted attention. In the multi-wire system, the increase in the number of metal wires in the metal wire wire shortens the effective current transfer distance from the current source to the metal wire wire, thereby reducing the electrical resistance and increasing the height of the solar cell module. It is possible to improve the photoelectric conversion efficiency.

  As a technology using a multi-wire method, Patent Document 2 discloses that a solar battery cell provided with a transparent conductive film on the surface, a finger electrode which is provided in contact with the transparent conductive film and serves as a collecting electrode, and the finger electrode A solar cell module is disclosed which has a plurality of metal wires arranged as interconnectors and in which finger electrodes are formed in broken lines.

Unexamined-Japanese-Patent No. 2007-103536 JP 2014-146697

  However, when the inventors etc. produced and evaluated the solar cell module of patent document 2, the fall of the photoelectric conversion efficiency was recognized in the heat cycle test. And the reason for the decrease in photoelectric conversion efficiency in the heat cycle test is that the solar cell is broken due to the increase in the number of metal wires connecting the electrode on the light receiving surface of the adjacent solar cell and the electrode on the back surface. 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 load on the solar cells is increased and the solar cells are broken, resulting in a decrease in photoelectric conversion efficiency. Do. From this, as in the solar cell module adopting the multi-wire system described in Patent Document 2, when the electrodes on the light receiving surface of the adjacent solar cells and the electrode on the back surface are connected using a large number of metal wires, the solar It has been found that the battery cell is heavily stressed, the solar cell is easily cracked, and the reliability is lowered.

  This invention is made 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 problems described above and to achieve the object, the solar cell module according to the present invention alternates between an n-type first crystal solar cell and a first crystal solar cell in which the light receiving surface side is a positive electrode. And a p-type second crystal solar cell whose light receiving surface side is a negative electrode. Moreover, the solar cell module connects electrodes on the light receiving surface side of the adjacent first crystal solar cell and second crystal solar cell, and the diameter is in the range of 0.2 mm to 1.0 mm. Opposite to the light receiving surface side of the first crystalline solar cell and the second crystalline solar cell adjacent to each other, and a plurality of light receiving surface side connection wires formed of six or more metal wire wires having a cross section of And a back surface side connection wiring made of a metal film that connects the electrodes on the back surface side with 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 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 the light-receiving surface side 1 is a schematic sectional view showing a solar cell module according to Embodiment 1 of the present invention The schematic top view which looked at the n-type solar cell concerning Embodiment 1 of this invention from the light-receiving surface side A schematic bottom view of the n-type solar battery cell according to the first embodiment of the present invention viewed from the back surface side facing the light receiving surface side 1 is a schematic cross-sectional view showing an n-type solar battery cell according to Embodiment 1 of the present invention The schematic top view which looked at the p-type solar cell concerning Embodiment 1 of this invention from the light-receiving surface side The schematic bottom view which looked at the p-type solar cell concerning Embodiment 1 of this invention from the back side 1 is a schematic cross-sectional view showing a p-type solar battery cell according to Embodiment 1 of the present invention The schematic cross section which shows the other structural example of the p-type solar cell concerning Embodiment 1 of this invention A schematic bottom view showing an example of an electrode-integrated back sheet in which the metal film and the back sheet according to Embodiment 1 of the present invention are integrated A schematic sectional view showing an example of an electrode-integrated back sheet in which the metal film and the back sheet according to Embodiment 1 of the present invention are integrated. A schematic top view showing a state in which the n-type solar battery cell and the p-type solar battery cell according to the first embodiment of the present invention are connected by metal wire wires A schematic cross-sectional view showing a state in which the n-type solar battery cell and the p-type solar battery cell according to the first embodiment of the present invention are connected by metal wire wires Model top view which shows the laminated body before the lamination concerning Embodiment 1 of this invention 1 is a schematic cross-sectional view showing a laminate before lamination according to Embodiment 1 of the present invention The schematic bottom view which looked at the solar cell array produced by arrange | positioning a ribbon-like metal film on the back surface of a n-type solar cell and a p-type solar cell in Example 3 from the back side. A schematic cross-sectional view of a solar cell array manufactured by arranging a ribbon-like metal film on the back surface of an n-type solar cell and a p-type solar cell in Example 3. A schematic top view showing the laminate before lamination in Example 3 A schematic cross-sectional view showing a 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 cross-sectional view showing a solar cell module of Example 3 Schematic top view showing the laminate before lamination in Example 4 A schematic cross-sectional view showing a 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 cross-sectional view showing a 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.

  Below, the manufacturing method of the solar cell module concerning the embodiment of the present invention and a solar cell module is explained in detail based on a drawing. In addition, this invention is not limited to the following description, It can change suitably in the range which does not deviate from the summary of this invention. Further, in the drawings shown below, the scale of each member may be different from the actual one for easy understanding. The same applies to each drawing.

Embodiment 1
FIG. 1 is a schematic top 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 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 side facing the light receiving side. FIG. 3 is a schematic cross-sectional view showing the solar cell module 1 according to the first embodiment of the present invention, and is a cross-sectional view taken along line III-III in FIG. Two orthogonal directions indicated by arrow X and arrow Y in FIG. 1 are referred to as a column direction and a row direction, respectively. Note that a view from the light receiving surface side is a top view, and a view from the opposite side is a bottom view.

  The solar cell module 1 according to the first embodiment is configured of 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 battery cell 10 n is a first crystalline solar battery cell that uses an n-type crystalline silicon substrate and has a light receiving surface as a positive electrode and a back surface facing the light receiving surface as a negative electrode. The p-type solar cell 10p is a second crystalline solar cell using a p-type crystalline silicon substrate, the light receiving surface being a negative electrode, and the back surface being a positive electrode. In addition, below, when not distinguishing n-type solar cell 10n and p-type solar cell 10p, it may only be called the solar cell 10 in some cases.

  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 wires 11 which are connection wiring on the light receiving side and metal films 12 which are connection wiring on the back side. The cells 10 are electrically connected in series.

  Further, in FIG. 1, the solar cells 10 at the ends of each row are electrically connected in series to each other by the solar cells 10 at the ends of adjacent rows and the horizontal tab lines 13. Thereby, all the solar cells 10 in the solar cell module 1 are electrically connected in series. Moreover, the cable which is not shown in figure connected 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 FIGS. 1 and 3, on the light receiving surface side of n-type solar battery cells 10n and p-type solar battery cells 10p adjacent in each row, a positive electrode on the light receiving surface side of n-type solar battery cells 10n A plurality of metal wire wires 11 electrically connecting in series the negative electrode on the light receiving surface side of the p-type solar battery cell 10p are provided. In FIGS. 1 to 3, the electrodes of the solar battery cell 10 are omitted. The details of the electrodes of the solar battery cell 10 will be described later. The metal wires 11 extend parallel to one another along the column direction. A set of solar battery cells 10 is constituted by adjacent n-type solar battery cells 10 n and p-type solar battery cells 10 p connected to each other by the metal wire 11. That is, the metal wire wire 11 is joined to the electrode of the positive electrode provided on the light receiving surface of the n-type solar battery cell 10n and the electrode of the negative electrode on the light receiving surface side of the p-type solar battery cell 10p in the same set. Thereby, the plurality of n-type solar cells 10 n and the p-type solar cells 10 p in each row are electrically connected in series by the multi-wire method using the plurality of metal wire lines 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 The metal film 12 which electrically connects in series the positive electrode on the back surface side of the p-type solar battery cell 10p is provided. The metal films 12 extend in parallel to one another along the column direction. The metal film 12 electrically series-connects the electrode on the back surface side of one solar battery cell 10 and the electrode on the back surface side of the other solar battery cell 10 in a pair of solar battery cells 10 adjacent between different sets. Connecting. That is, the metal wire wire 11 is joined to the electrode of the positive electrode provided on the light receiving surface of the n-type solar battery cell 10n and the electrode of the negative electrode on the light receiving surface side of the p-type solar battery cell 10p in the same set.

  The plurality of solar cells 10 are sealed by a sealing material 22 made of a translucent resin, and a glass substrate 21 which is a translucent light receiving surface side protective 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. For the sealing material 22, a thermosetting resin having translucency such as ethylene-vinyl acetate (EVA) can be used. For the light receiving surface side protective member, a translucent material such as transparent glass or a transparent film can be used.

  For 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 10 n 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 battery cell 10 n 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 n-type solar battery cell 10n according to the first embodiment of the present invention, and is a cross-sectional view taken along line VI-VI in FIG. The n-type solar battery cell 10 n has a structure of a general solar battery cell mass-produced as an n-type solar battery cell, and has a photoelectric conversion efficiency of about 20% at maximum.

  The n-type solar battery cell 10 n is a crystalline solar cell using a crystalline semiconductor substrate. In the n-type solar battery cell 10n, a p-type impurity diffusion layer 32 as an impurity diffusion layer is formed by boron diffusion on the light receiving surface side of the 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 light receiving surface side of the n-type silicon layer 31, minute unevenness (not shown) is formed as a texture structure. The minute asperities increase the area of the light receiving surface to absorb light from the outside, suppress the reflectance on the light receiving surface, and confine light. In addition, an antireflective film may be provided on the surface of the n-type silicon layer 31 on the light receiving surface side.

  In addition, on the light receiving surface side of the n-type solar battery cell 10n, that is, on the light receiving surface side on the p-type impurity diffusion layer 32, a plurality of light receiving surface electrodes are formed of an electrode material containing silver and glass and have an elongated shape. A grid electrode 34 is provided electrically connected to the p-type impurity diffusion layer 32 at the bottom surface. That is, the plurality of grid electrodes 34 constitute a light receiving surface electrode which works 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 battery cell 10n, that is, the back surface side of the n-type silicon layer 31 so as to cover the entire back surface. That is, the back surface aluminum electrode 35 constitutes a back surface electrode acting as a negative electrode.

  The plurality of metal wire wires 11 are disposed on the grid electrode 34 in a state where the longitudinal direction of the metal wire wire 11 and the longitudinal direction of the grid electrode 34 of the n-type solar battery cell 10 n are orthogonal to each other. In FIG. 4, the arrangement position of the metal wire wire 11 on the light receiving surface side of the n-type solar battery cell 10 n is indicated by a dotted line. Moreover, the metal film 12 is arrange | positioned on the back surface aluminum electrode 35 in the state which the longitudinal direction of the metal film 12 and the longitudinal direction of the grid electrode 34 of the n-type solar cell 10n orthogonally cross. 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 10 p 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 as viewed from the back surface side. FIG. 9 is a schematic cross-sectional view showing a p-type solar battery cell 10p according to the first embodiment of the present invention, and is a cross-sectional view taken along line IX-IX in FIG.

  The p-type solar battery cell 10p is a crystalline solar cell using a crystalline semiconductor substrate. In the p-type solar battery cell 10p, an n-type impurity diffusion layer 42 as an impurity diffusion layer is formed by phosphorus diffusion on the light receiving surface side of a p-type silicon layer 41 made of a p-type silicon substrate which is a p-type semiconductor substrate. ing. A depletion layer 43 is formed in the vicinity of the junction surface between the p-type silicon layer 41 and the n-type impurity diffusion layer 42. In addition, on the surface of the light receiving surface side of the p-type silicon layer 41, minute unevenness (not shown) is formed as a texture structure. The minute asperities increase the area of the light receiving surface to absorb light from the outside, suppress the reflectance on the light receiving surface, and confine light. Further, an antireflective film may be provided on the surface of the p-type silicon layer 41 on the light receiving surface side.

  Further, on the light receiving surface side of the p-type solar battery cell 10p, that is, on 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 electrically connected to the n-type impurity diffusion layer 42. That is, the plurality of grid electrodes 44 constitute a light receiving surface electrode which works as a negative electrode.

  On the other hand, on the back surface of the p-type silicon layer 41, a back surface passivation film 46 made of a silicon nitride film is provided over the entire surface. A silicon oxide film may be used as the back surface passivation film 46. The back surface passivation film 46 is provided with dot-shaped contact holes 46 a reaching the back surface of the p-type silicon layer 41. Then, a back surface aluminum electrode 45 made of an electrode material containing aluminum and glass is provided on the back surface passivation film 46 so as to fill the contact holes 46 a and to cover the entire surface of the back surface passivation film 46. That is, the back surface aluminum electrode 45 constitutes a back surface electrode acting as a positive electrode.

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

  In contact hole 46 a, an alloy layer 47 of aluminum and silicon is formed between p-type silicon layer 41 and 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 A back surface field (BSF) layer 48, which is a high concentration p + region, is formed. The back surface aluminum electrode 45 is electrically connected to the p-type silicon layer 41 via the alloy layer 47 and the BSF layer 48.

  The p-type solar battery cell 10p shown in FIG. 7 to FIG. 9 is a back side passive cell (Passivated Emitter and Rear Cell: PERC) formed in the same size as the n-type solar battery cell 10n. The PERC cell aims to improve the photoelectric conversion efficiency by reducing recombination occurring at the interface between the p-type silicon layer on the back surface of the solar cell and the aluminum electrode using a passivation film provided on the back surface of the solar cell. It is a solar cell that can be The photoelectric conversion efficiency of a general p-type single crystal solar cell without a passivation film on the back surface is about 16%. On the other hand, when a PERC cell is used, it is possible to improve the photoelectric conversion efficiency to about 20%.

  Generally, the current generated by the n-type solar cell is larger than that of the p-type solar cell. Therefore, when n-type solar cell 10n and p-type solar cell 10p are alternately connected in series, the amount of current generated by n-type solar cell 10n and the current generated by p-type solar cell 10p There is a difference in the amount of current with the amount. Then, a loss occurs in the photoelectric conversion efficiency of the solar cell module due to the difference in the amount of current, that is, the output difference. Further, when there is a difference between the amount of current generated by the n-type solar battery cell 10n and the amount of current generated by the p-type solar battery cell 10p, even if a bypass diode is provided, the amount of generated current p is small. Solar cells tend to be hot spots. Then, discoloration of the back sheet due to heat or solder failure may cause the diode to be constantly energized, and may subsequently cause a diode failure and further heat generation of the solder failure portion.

  For this reason, in the first embodiment, the power generation characteristics of the p-type solar battery cell 10p are changed to the n-type solar cell by using the p-type solar battery cell of a type capable of realizing high photoelectric conversion efficiency for the p-type solar battery cell 10p. 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 battery cell 10p, the power generation characteristics of the p-type solar battery cell 10p are brought close to the power generation characteristics of the n-type solar battery cell.

  That is, the n-type solar battery cell 10n according to the first embodiment is an n-type solar battery cell having a photoelectric conversion efficiency of about 20% at maximum. 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%. And in this Embodiment 1, the difference of the electric current amount at the time of electric power generation of n type solar cell 10n and p type solar cell 10p is made into ± 5% or less. Thereby, in the first embodiment, n-type solar battery cells 10n and p-type solar battery cells 10p having different polarities are alternately connected in series, while n-type solar battery cells 10n and p-type solar battery cells 10p are alternately connected. The amount of generated current can be balanced, and generation of a hot spot and generation of loss of photoelectric conversion efficiency due to output difference 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. In addition to the above-described PERC cell, as a p-type solar battery cell of a type capable of realizing high photoelectric conversion efficiency in order to bring the power generation characteristics of the p-type solar battery cell 10p close to the power generation characteristics of the n-type solar battery cell 10n, Q cell manufactured by Q cell shown in FIG. Like ANTUM cells (registered trademark), it is possible to use a solar battery cell that reflects light passing through a silicon substrate and reuses it for power generation.

  In the solar cell shown in FIG. 10, a plurality of n-type impurity diffusion layers 52, depletion layers 53, and a plurality of light-receiving surface electrodes are formed on the light-receiving surface side of p-type silicon layer 51 made of p-type silicon substrate which is a p-type semiconductor substrate. Grid electrodes 54 are provided. In addition, on the back surface 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 battery cell, the light passing through the p-type silicon layer 51 to the back surface side is reflected by the reflective coating layer 56 and reused for power generation, whereby the photoelectric conversion efficiency can be improved. In particular, this technology is effective when applied to thin solar cells that are easy to transmit light. For example, when applied to a solar battery cell having a thickness of 150 μm or less, the effect of improving the photoelectric conversion efficiency is large. The reflective coating layer 56 can be formed, for example, by depositing a metal film on the back side of the p-type silicon layer 51.

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

  The metal wire 11 is a metal wire 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 11 is circular, the sunlight hitting the metal wire 11 becomes reflected light that is reflected in various directions, and the reflected light enters the solar battery cell 10 and the photoelectric conversion efficiency is Contribute to improvement.

  When the cross-sectional shape of the metal wire 11 is elliptical, the solar battery cell can be obtained by arranging the plurality of metal wires 11 such that the arrangement direction of the plurality of metal wires 11 is along the major axis of the ellipse. There are more regions shaded by the metal wire 11 on the light receiving surface 10. 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 such that the arrangement direction of the plurality of metal wire wires 11 is along the direction of the minor axis of the ellipse, the contact area between the metal wire wire 11 and the grid electrode is reduced. Thereby, the bonding area between the metal wire 11 and the grid electrodes 34 and 44 is reduced, and the metal wire 11 is easily detached from the grid electrodes 34 and 44. Therefore, the connection between the metal wire 11 and the grid electrodes 34 and 44 Less reliable.

  On the other hand, when the cross-sectional shape of the metal 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 11 and the grid electrode is properly maintained. Furthermore, there is no need for circumferential alignment of the cross section 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 smaller than 0.2 mm, the contact area with the grid electrodes 34 and 44 decreases. As a result, the bonding area between the metal wire 11 and the grid electrodes 34 and 44 is reduced, and the metal wire 11 is easily detached from the grid electrodes 34 and 44. Therefore, the metal wire 11 and the grid electrodes 34 and 44 Poor connection reliability. Moreover, when the diameter of the metal wire wire 11 is thicker than 1.0 mm, the area | region which becomes a shade by the metal wire wire 11 in the light-receiving surface of the photovoltaic cell 10 will increase. 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, a round chamfered shape in four corners. In the first embodiment, the number of metal wire wires 11 is seven. When the number of the metal wire wires 11 is less than six, it is easily affected by the resistance components of the grid electrodes 34 and 44, and the photoelectric conversion efficiency is reduced. When the number of the metal wire 11 is more than 17, the resistance components of the grid electrodes 34 and 44 decrease, but the area of the light receiving surface of the solar cell 10 which is shaded by the metal wire 11 is increased. Thereby, the sunlight which injects into the photovoltaic cell 10 decreases, and the photoelectric conversion efficiency of the photovoltaic cell 10 falls.

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

  Moreover, in the connection method of the metal wire 11 and the grid electrodes 34 and 44, the metal wire 11 is in contact with the grid electrodes 34 and 44, and from above the metal wire 11 and the grid electrodes 34 and 44. A method of pressing with a tape, sheet or gel can be used. In the case of pressing the metal wire 11 and the grid electrodes 34 and 44 from above with tape, sheet or gel, the tape, sheet or gel is transparent and has excellent light transmittance. Besides, pressure welding using a sealing material can be used.

  In the first embodiment, the solder is melted by heating while pressing the metal wire 11 against the grid electrodes 34 and 44 using the metal wire 11 coated with solder in advance, and the metal wire 11 is a grid Bond to the electrodes 34, 44.

  The metal film 12 is made of a foil, a film or a film, and is a metal wiring wider than the metal wire 11. In the present embodiment, the metal foil, the metal film or the metal film is generically referred to as a metal film. The metal film 12 has a flat film shape, and in order to surface-connect the back surface aluminum electrodes 35 and 45 on the back surface of the solar battery cell 10, the connection resistance to the back surface aluminum electrodes 35 and 45 can be reduced. The stress applied to the solar battery cell 10 can be reduced.

  As a material of the metal film 12, for example, copper having high conductivity is used. In the first embodiment, a copper foil which is a metal foil is used as the metal film 12. The number of metal films 12 connecting the solar battery cells 10 is not particularly limited, and may be one or more, or two or more. A plurality of ribbon-shaped metal films 12 may be used. In the first embodiment, one copper foil is used as the metal film 12.

  Since the back surface of the solar cell 10 does not need to be exposed to light, the metal film 12 preferably has a shape that maintains low electric resistance bonding and does not stress the solar cell 10. That is, in the case of a solar cell module structure using an opaque back sheet, since it is not necessary to transmit sunlight on the back surface of the solar cell 10, connection between adjacent solar cells 10 is a multi-wire method. There is no need to use it. And, by using a foil-like, film-like or film-like connection wiring, stress applied to the solar battery cell 10 can be reduced, and problems due to cell breakage can be reduced.

  The thickness of the metal film 12 is preferably 0.02 mm or more and 0.3 mm or less. If the thickness of the metal film 12 is less than 0.02 mm, the electrical resistance of the metal film 12 becomes large, and the handling of the metal film 12 becomes difficult. In addition, when the thickness of the metal film 12 is thicker than 0.3 mm, at the time of lamination due to the step formed by the surface of the back surface aluminum electrodes 35 and 45 of the back surface of the solar battery cell 10 and the metal film 12 Stress is applied to the solar battery cell 10, and cell breakage tends to occur in the solar battery cell 10. In addition, in consideration of the conductivity of the metal film 12, the thickness of the metal film 12 of 0.3 mm or less is sufficient.

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

  As another method, a metal film is mounted by mounting an electrode integrated back sheet in which the metal film 12 and the back sheet are integrated on the surface of the back surface aluminum electrodes 35, 45 and laminating the solar cell module. There is a method of connecting the solar battery cells 10 with each other using T.12.

  As a method of integrating the metal film 12 and the back sheet, there is a method of metal plating on one side of the back sheet, a method of thermocompression bonding of a metal foil to the back sheet, and a back sheet of the metal film 12 using an adhesive. For example, a method of pasting on is applicable. In either case, patterning of the metal foil by etching is required after the metal foil is integrated with the back sheet.

  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 Embodiment 1 of the present invention are integrated, and is a cross section along line IIX-II in FIG. FIG. By integrating the metal film 12 with the back sheet 23, it is possible to give the back sheet 23 a back surface wiring function.

  In the electrode-integrated back sheet 24 shown in FIGS. 11 and 12, an adhesive layer 61 is formed on one side of the back sheet 23 formed in advance, 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, it is possible to facilitate bonding of the metal film 12 and the back surface aluminum electrode 45. 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, handling of the material constituting the adhesive layer 61 becomes difficult. When the thickness of the adhesive layer 61 is greater than 50 μm, it becomes difficult for the adhesive layer 61 to deform 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 external force causes cell Cracking is likely to occur, etc.

  In addition, the other method of connecting the metal film 12 and the back surface aluminum electrodes 35 and 45 on the back surface of the solar battery cell 10 may use the same method as the bonding of the metal wire wire 11 and the grid electrodes 34 and 44. it can.

  Either of the method of using the single metal film 12 or the method of using the electrode integrated back sheet 24 in which the metal film 12 and the back sheet 23 are integrated, the plane of the back aluminum electrodes 35 and 45 and the metal film 12 In order to connect them, 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, the stress applied to the solar battery cell 10 is widely dispersed as compared with a general tab wire connection, that is, the case where the back aluminum electrodes 35 and 45 are connected to the tab wire through the bus electrodes, The effect that the cell breakage of the cell 10 hardly occurs is obtained.

  When the bonding area between the metal film 12 and the back surface aluminum electrodes 35 and 45 is large, cell breakage occurs in the solar battery cell 10 due to the thermal expansion difference between the metal film 12 and the back surface aluminum electrodes 35 and 45 There is a possibility of Therefore, when the bonding area between the metal film 12 and the back surface aluminum electrodes 35, 45 is large, the bonding between the metal film 12 and the back surface aluminum electrodes 35, 45 is preferably a large number of point connections. As an example of a large number of point connections, solder paste is printed on back surface aluminum electrodes 35 and 45 in lattice points at intervals of 10 mm, for example, and metal film 12 is connected to back surface aluminum electrodes 35 and 45 via solder paste.

  When using ACF or a conductive adhesive, applying ACF or a conductive adhesive to the entire surface of the metal film 12 is costly and causes the difference in thermal expansion between the metal film 12 and the back surface aluminum electrodes 35 and 45 to cause the sun Cell breakage may occur in the battery cell 10. Therefore, even when using an ACF or a conductive adhesive, without placing the ACF or the conductive adhesive on the entire surface of the metal film 12, a gap is opened in the surface of the metal film 12 to form an ACF or a conductive adhesive. It is preferable that the metal film 12 and the back surface aluminum electrodes 35, 45 be joined by partially arranging them.

  Moreover, when using pressure welding using a sealing material, the stress applied to the metal film 12 and the back surface aluminum electrodes 35 and 45 due to the thermal expansion difference is small, but the contact caused due to the deterioration of the surface of the metal film 12 Poor is a concern. For this reason, it is necessary to select the metal film 12 from a material which does not cause a conductive failure due to oxidation, such as nickel (Ni) plated copper foil, tin (Sn) plated copper foil, silver (Ag) plated copper foil.

  As described above, even when the cross-sectional shape of the metal wire 11 is circular, a large number of metal wires are disposed by causing the surface of one of the adjacent solar cells to wrap around to the back of the other solar cell. It became clear by examination of the inventors et al. That, when installed, large stress is applied to the solar cell at a portion where the curvature is large, and cell breakage of the solar cell tends to occur. And it became clear that cell breakage of a photovoltaic cell becomes more likely to occur by adopting a multi-wire system and increasing the number of wires.

  So, in the solar cell module 1 concerning this Embodiment 1, the n-type solar cell 10n and the p-type solar cell 10p are arrange | positioned alternately as the solar cell 10 arrange | positioned at the same line. As a result, between the n-type solar cell 10n and the p-type solar cell 10p adjacent to each other, there is no need to pass the metal wire line 11 from the light receiving surface side to the back side, and the metal wire line 11 does not bend. The grid electrode 34 of the n-type solar battery cell 10n and the grid electrode 44 of the p-type solar battery 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 wire 11, and cell breakage of the solar battery cell 10 due to the stress applied from the metal wire wire 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. Since the bus electrode is not used, the alignment of the metal wire line 11 to the bus line is performed. Also, the connection process of the metal wire line 11 is simplified. Furthermore, since no bus electrode is used, connection failure due to the bus electrode does not occur.

  Below, the manufacturing method of the solar cell module 1 concerning this Embodiment 1 is demonstrated. Here, the case of using the electrode-integrated back sheet 24 in which the metal film 12 and the back sheet 23 are integrated will be described. First, an n-type solar battery cell 10 n and a p-type solar battery cell 10 p which is a PERC cell are formed by a known method.

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

  Next, the metal wire wire 11 which is a solder plated copper wire in which a solder is plated on the surface of a 0.2 mm diameter copper wire is the grid electrode 34 of the n-type solar cell 10n and the grid electrode of the p-type solar cell 10p. They are disposed on the grid electrode 34 and on the grid electrode 44 in a state of being orthogonal to 44. Then, by pressing the metal wire 11 from above to thermally melt the solder on the surface of the metal wire 11 so that the metal wire 11 is not displaced, the metal wire 11 can be used as the grid electrode 34 and the grid electrode. It adhere | attaches 44 and as shown to FIG. 13 and FIG. 14, the n-type solar cell 10n and the p-type solar cell 10p are connected by the metal wire wire 11. As shown in FIG.

  Next, a pressure-sensitive adhesive dissolved in a solvent is applied to the surface of the back sheet for a solar cell made of PET, which is on the sealing material 22 side, and the solvent is dried to form a pressure-sensitive adhesive layer 61 with a thickness of about 35 μm. Ru. 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 adhered 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 Embodiment 1 of the present invention. FIG. 16 is a schematic cross-sectional view showing the laminate 25 before lamination according to Embodiment 1 of the present invention, and is a cross-sectional view taken along line XVI-XVI in FIG. In addition, in FIG. 15, the state which permeate | transmitted and looked at the back sheet 23 and the adhesion layer 61 among the electrode integrated back sheets 24 is shown. A sealing material sheet 22a for a solar cell made of an EVA sheet is placed on a glass substrate 21 made of white sheet glass, which is a light receiving surface side protective member. Next, the 25 sets of solar battery cells 10 are arranged on the sheet of the sealing material 22 in an array with the metal wire wire 11 side facing the glass substrate 21. Also, a horizontal tab wire 13 and a terminal box cable for wire connection to the terminal box are disposed on the sheet of the sealing material 22.

  The metal film 12 is placed on the back aluminum electrode 35 of the n-type solar battery cell 10 n and the back aluminum electrode 45 of the p-type solar battery cell 10 p, and the electrode integrated back sheet 24 is placed thereon. The front laminate 25 is formed. Thereafter, the laminate 25 before lamination is thermocompression-bonded by pressing and heating for 30 minutes at 150 ° C., for example, with a vacuum thermal laminator, to obtain the solar cell module 1 having the structure shown in FIG. 1 to FIG. Thereafter, a terminal box (not shown) connected to the terminal box cable is disposed on the electrode-integrated back sheet 24 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 cells 10 n and the p-type solar cells 10 n are alternately arranged by alternately arranging the n-type solar cells 10 n and the p-type solar cells 10 p. The metal wire wire 11 and the metal film 12, which are wires electrically connecting the battery cells 10p in series, can be used in a straight state without bending. Thereby, the stress applied to the solar cell 10 due to the bending of the wiring connecting the adjacent solar cells 10 can be reduced, and the cell breakage of the solar cell 10 can be prevented.

  Further, in the solar cell module 1 according to the first embodiment, the multi-wire method is used for connection between the n-type solar cell 10 n and the p-type solar cell 10 p on the light receiving surface side. Since the effective moving distance of the current 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.

  In addition, in the solar cell module 1 according to the first embodiment, surface connection by the metal film 12 having a flat film shape is used for connection between the n-type solar cell 10n and the p-type solar cell 10p on 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 reduced, 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 solar cell 10 resulting from the connection of solar cell 10 adjacent comrades, the photoelectric conversion efficiency of the solar cell 10 is made. Thus, it is possible to obtain a solar cell module capable of improving the photoelectric conversion efficiency and the reliability.

  Below, it demonstrates based on a specific Example.

Example 1
According to the manufacturing method of the solar cell module concerning Embodiment 1 mentioned above, the solar cell module was produced and it was set as the solar cell module of Example 1. FIG. As the n-type solar cell 10n and the p-type solar cell 10p, a solar cell having a size of 156 mm square and a thickness of 175 μm was used. The difference in the amount of current at the time of power generation between the n-type solar battery cell 10n and the p-type solar battery cell 10p is within ± 5%. As the metal wire 11, seven solder-plated copper wires having a diameter of 0.2 mm were used.

  In addition, on the side of the back sheet made of PET with an outer diameter of 1700 mm × 900 mm and a thickness of 0.2 mm and placed on the metal film 12 side, a pressure-sensitive adhesive dissolved with a solvent is applied to dry the solvent. Adhesive layer 61 having a thickness of about 50 μm. Then, an 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. For the glass substrate, white sheet glass having an outer diameter of 1600 mm × 800 mm and a thickness of 3.2 mm was used. As the encapsulant sheet 22a, an encapsulant sheet for solar cells made of EVA having a thickness of 0.6 mm was used.

Example 2
The same as Example 1, except that "six solder plated copper wires of 1.0 mm diameter" was used as the metal wire 11 instead of "seven solder plated copper wires of 0.2 mm diameter". A solar cell module was produced and used as a 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, to obtain a solar cell module of Example 3. FIG. 17 is a schematic diagram of a solar cell array 62 produced by arranging the ribbon-like metal film 12 on the back surface of the n-type solar battery cell 10 n and the p-type solar battery cell 10 p 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 a ribbon-shaped metal film 12 on the back surface of the n-type solar cell 10n and the p-type solar cell 10p in Example 3; It is sectional drawing in the XVIII-XVIII line in FIG.

  In Example 3, 25 pairs of solar battery cells 10 connected as shown in FIG. 13 and FIG. 14 are arranged in 10 columns × 5 rows with the back surface facing upward, and the horizontal tab line 13 and the terminal box cable are arranged. . Then, 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 10n and the p-type solar cell. The back side aluminum electrodes 45 of the battery cells 10 p were mounted in two rows. An ACF 63 is disposed on one surface of the tin (Sn) plated copper foil on the solar battery cell 10 side. Then, the ACF was thermocompression-bonded to each tin (Sn) -plated copper foil by a heat roll at a temperature at which the solder does not melt, thereby producing a 10-row × 5-row solar cell array 62 as shown in FIGS. .

  FIG. 19 is a schematic top view showing a laminate 64 before lamination in Example 3. FIG. 20 is a schematic cross-sectional view showing a laminate 64 before lamination in Example 3, and is a cross-sectional view taken along 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. FIG. 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.

  The sealing material sheet 22a, the solar cell array 62, the sealing material sheet 22a, and the back sheet 23 are laminated in this order on the glass substrate 21 to form a laminated body 64 before lamination shown in FIGS. 19 and 20. did. Thereafter, the laminate 64 before lamination is thermocompression bonded by pressing and heating with a vacuum thermal laminator to obtain a solar cell module of Example 3 having a structure shown in FIG. 21 and FIG.

Example 4
FIG. 23 is a schematic top view showing a laminate 66 before lamination in Example 4. FIG. 24 is a schematic cross-sectional view showing a laminate 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 surface side. FIG. 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, n-type solar cells 10n and p-type solar cells 10p were connected by metal wire wires 11 in the same manner as in Example 1 to form sets of 25 solar cells 10.

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

  On the back surface aluminum electrode 35 of the n-type solar battery cell 10n and the back surface aluminum electrode 45 of the p-type solar battery cell 10p having a thickness of 70 μm and made of a nickel (Ni) plated electrolytic copper foil It put together and mounted and soldered with the horizontal tab wire 13. A two-layered laminated back sheet 65 was placed thereon to form a laminated body 66 before lamination shown in FIGS. 23 and 24. In the laminated back sheet 65, an inner back sheet layer 65a made of thermoplastic type polyolefin and arranged on the inner side of the solar cell module 1, and an outer back sheet layer made of polyethylene terephthalate and arranged on the outer side of the solar cell module 1. The laminated back sheet 65 in which 65b and were laminated was used.

  Thereafter, the laminate 66 before lamination is thermocompression bonded by pressing and heating at 150 ° C. for 30 minutes with a vacuum thermal laminator, for example, to obtain a solar cell module having a structure shown in FIGS. 25 and 26. 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 65 a of the laminated back sheet 65 is softened, the encapsulating material sheet 22 a for a solar cell made of thermally crosslinkable polyolefin having a heat softening temperature of about 60 ° C. is melted And cover the solar battery cell 10. On the other hand, although the polyolefin of the inner back sheet layer 65a is softened and exhibits adhesiveness, it does not melt and flow. For this reason, the polyolefin of the inner backsheet layer 65a does not enter between the metal film 12 and 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. Thereby, since the metal film 12 is reliably pressed to the back surface aluminum electrode 35 and the back surface aluminum electrode 45, favorable electrical connection 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 Comparative Example 1, a commonly used solar is used, in which p-type solar cells in which the n-type and p-type of the component in the n-type solar cell 10 n are reversed are arranged in 10 columns × 5 rows. A battery module was produced. The p-type solar battery 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 a negative electrode, and the back surface of the p-type silicon substrate is a positive electrode It is done. On the light receiving surface side of the p-type solar battery cell, a plurality of grid electrodes formed by printing and firing silver paste and four bus electrodes extending in a direction orthogonal to the grid electrodes are provided. On the back surface side of the p-type solar battery cell, a back surface aluminum electrode is formed on the entire surface as in the above-described n-type solar battery cell 10n, and four bus electrodes are formed thereon.

  The p-type solar cells adjacent to each other in the same row are soldered four tab wires to the bus electrode on the light receiving surface side of one p-type solar cell and the bus electrode on the back side of the other p-type solar cell They are electrically interconnected in series. The tab wire is a solder coated copper wire and is joined to the bus electrode by melting the solder. The tab line is greatly bent and disposed to pass from the light receiving surface side to the back surface side between the adjacent p-type solar cells. Also, the p-type solar cells at the ends of adjacent rows are electrically interconnected in series by the horizontal tabs that are solder-coated copper wires. Thereby, all p type solar cells are electrically connected in series.

Comparative Example 2
The same p-type solar cells as in Comparative Example 1 are arranged in 10 columns and 5 rows, and an EVA sealing material having a thickness of 0.4 mm is placed on the p-type solar cells, and further 0.2 mm in thickness A solar cell module was produced by the multi-wire method in the same manner as in Example 1 except that thermocompression bonding was performed by placing the PET back sheet of the above and pressing and heating with a vacuum heat laminator.

Comparative Example 3
The same as Comparative Example 1 except that “six solder plated copper wires of 1.0 mm diameter” were used instead of “seven solder plated copper wires of 0.2 mm diameter” as metal wire wire 11 A solar cell module was produced and used as a solar cell module of Comparative Example 3.

Comparative Example 4
The same as Example 1, except that "seven solder plated copper wires having a diameter of 0.15 mm" was used as the metal wire 11 instead of "seven solder plated copper wires having a diameter of 0.2 mm" A solar cell module was produced and used as a solar cell module of Comparative Example 4.

Comparative Example 5
The same as Example 1, except that "six solder plated copper wires of 1.5 mm diameter" was used as the metal wire 11 instead of "seven solder plated copper wires of 0.2 mm diameter" A solar cell module was produced and used as a solar cell module of Comparative Example 5.

(Evaluation test)
About the solar cell module of Example 1 to Example 4 and Comparative Example 1 to Comparative Example 5 which were produced as mentioned above, the initial maximum output was measured using the solar simulator. Furthermore, 1000 cycles of heat cycle tests at two temperatures of −40 ° C. and 105 ° C. were performed, and the maximum power 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.

  In the solar cell module of Example 1, it is not necessary to pass the metal wire line 11 from the light receiving surface side to the back surface side between the n-type solar cell 10n and the p-type solar cell 10p adjacent to each other. Also, alignment to the bus electrode is not necessary. For this reason, in the solar cell module according to the first embodiment, the connection failure of the metal wire 11, that is, the disconnection of the metal wire 11 does not occur. Moreover, the solar cell module of Example 1 becomes 1.125 times the initial maximum output of the solar cell module of Comparative Example 1 by adopting the multi-wire system, and the photoelectric conversion efficiency is 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 the number of 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. In addition, the solar cell module of Example 2 is 1.1 times as large as 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 improved by 10.0%.

  The solar cell module of Example 3 adopts the same multi-wire system 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, as in the solar cell module of Example 1, and photoelectric conversion Efficiency increased by 12.5%.

  The solar cell module of Example 4 adopts the same multi-wire system as the solar cell module of Example 1. For this reason, in the solar cell module of Example 4, the connection failure of the metal wire 11 is eliminated. 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 high initial maximum power, and no decrease in maximum power after heat cycle is observed. On the other hand, in the solar cell modules of Comparative Examples 1, 2, 3, 4 and 5, a significant decrease in maximum output was observed after the heat cycle.

  The solar cell module of Comparative Example 1 had a lower initial maximum power as compared with the example employing the multi-wire system. From this result, it can be seen that the multi-wire system 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 breakage after the heat cycle was not observed.

  Further, as a result of analysis, in the solar cell modules of Comparative Example 2 and Comparative Example 3, the cell breakage of the solar cell module occurs at 200 or more places after the heat cycle, which is a main cause of the low initial maximum output. Conceivable.

  In the solar cell module of Comparative Example 4, cell breakage of the solar cell module was not observed. This is caused by the metal wire 11 because the connection failure of the metal wire 11 occurs because the diameter of the metal wire 11 is too thin, that is, the metal wire 11 is separated from the grid electrode. It is considered that no broken cells have occurred.

  Further, according to the analysis result of the maximum output after the heat cycle, in the solar cell module of Comparative Example 4, the connection failure between the metal wire 11 and the grid electrode, that is, the metal wire 11 is separated from the grid electrode, It turned out that the output is falling. The reason why cell breakage of the solar cell module of Comparative Example 4 is not recognized is considered to be stress relaxation due to connection failure.

  In the solar cell module of Comparative Example 5, the cell breakage of the solar cell module remained at 50 places, 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 as the solar cell module of Example 1, but because the metal wire wire is too thick, the sunlight incident on the solar cell is It is considered that the decrease in the photoelectric conversion efficiency of the solar battery cell is the main cause of the low initial maximum output.

  The configuration shown in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and one of the configurations is possible within the scope of the present invention. Parts can be omitted or changed.

  DESCRIPTION OF SYMBOLS 1 solar cell module, 10 solar battery cell, 10 n n-type solar battery cell, 10 p p-type solar battery 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, 46 a contact hole, 47 alloy layer, 48 back 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, 65 stack back Over door, 65a inside the back sheet layer, 65b outside the back sheet layer.

Claims (10)

An n-type first crystal solar cell whose positive electrode is a light receiving surface side,
A p-type second crystalline solar cell which is alternately juxtaposed to the first crystalline solar cell and the light receiving surface side is a negative electrode;
Connect the electrodes on the light receiving surface side of the first crystal solar cell and the second crystal solar cell adjacent to each other, and have a circular cross section with a diameter in the range of 0.2 mm to 1.0 mm 6 A plurality of light receiving surface side connection wires made of metal wires of metal wires or more;
Back surface side connection wiring which consists of a metal film which connects the electrodes of the back surface side which opposes the light receiving surface side of said 1st crystal system solar cell and 2nd crystal system solar cell which adjoins,
A solar cell module comprising: The thickness of the back side connection wiring is 0.3 mm or less
The solar cell module according to claim 1, characterized in that A back sheet is provided on the back side of the back side connection wiring,
The back 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, characterized in that A light receiving surface side protective 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 crystalline solar cell except the bonding surface between the electrode on the back side of the first crystalline solar cell and the second crystalline solar cell, and the back side connection wiring. A crystalline solar cell, 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 protective member and the back sheet,
The back side connection wiring side in the back sheet is made of a thermoplastic resin having a melting point higher than that of the sealing material,
The electrode on the back surface side of the first crystal solar cell and the second crystal solar cell is in direct contact with the back surface connection wiring,
The solar cell module according to any one of claims 1 to 3, characterized in that The electrode on the back surface side of the first crystalline solar battery cell and the second crystalline solar battery cell, and the back surface side connection wiring are solder, conductive adhesive, metal paste, anisotropic conductive film or conductive Being joined by the adhesive double-sided tape,
The solar cell module according to claim 1, characterized in that An arrangement step of alternately arranging an n-type first crystalline solar cell whose light receiving surface side is a positive electrode and a p-type second crystalline solar cell whose light receiving surface side is a negative electrode;
The electrodes on the light receiving surface side of the first crystal solar cell and the second crystal solar cell adjacent to each other have six or more circular cross sections each having a diameter of 0.2 mm to 1.0 mm. A light receiving surface side connecting step of connecting by a plurality of light receiving surface side connecting wires made of metal wires of metal;
A back surface side connecting step of connecting electrodes on the back surface side facing the light receiving surface sides of the first crystal type solar battery cell and the second crystal type solar battery cell adjacent to each other by a back surface side connection wiring made of a metal film;
A manufacturing method of a solar cell module characterized by including. The thickness of the back side connection wiring is 0.3 mm or less
The manufacturing method of the solar cell module of Claim 6 characterized by these. Before the back side connection step, there is a step of fixing the back side connection wiring on one side of the back sheet via 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 the back electrode of the first crystal solar cell and the second crystal solar cell, and the first crystal solar cell and the second crystal solar cell are disposed. Connecting the electrodes on the back side of the solar cell with the back side connection wiring,
The manufacturing method of the solar cell module of Claim 7 characterized by these. After the back side connection step,
A sheet of sealing material, the first crystalline solar cell and the second crystalline solar cell connected by the back surface side connection wiring and the light receiving surface side connection wiring on the light receiving surface side protective member; The electrodes on the back side of the first crystalline solar cell and the second crystalline solar cell are stacked by laminating the electrode integrated back sheet in this order, pressing and heating, and the back side Direct contact with connection wiring,
The manufacturing method of the solar cell module as described in any one of Claim 6 to 8 characterized by these. In the back surface side connection step, the electrode on the back surface side of the first crystal solar cell and the second crystal solar cell and the back surface connection wiring are soldered, conductive adhesive, metal paste, Bonding with anisotropic conductive film or conductive double-sided tape,
The manufacturing method of the solar cell module of Claim 6 characterized by these.

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