JP5406900B2 - Solar cell module and manufacturing method thereof - Google Patents

Description

  The present invention relates to a solar cell module capable of using a wiring substrate made of various resin materials and a method for manufacturing the same.

  In recent years, development of clean energy sources has been desired due to problems of depletion of energy resources and global environmental issues such as an increase in carbon dioxide in the atmosphere. In particular, solar power generation using solar cells is a new energy source. Developed, put into practical use, and are on the path of development. As a solar cell, a pn junction is formed by diffusing reverse conductivity type impurities on the light-receiving surface of a single-crystal or polycrystalline single-conductive silicon substrate, and electrodes are formed on the light-receiving surface and the back surface of the silicon substrate, respectively. Conventionally, a solar cell module configured by connecting a plurality of solar cells has been mainstream.

  In addition, solar cells that achieve high output by a back surface field effect by forming an impurity layer containing impurities of the same conductivity type at a high concentration on the back surface of one conductivity type silicon substrate are also common. Furthermore, a so-called back electrode type solar cell has been developed in which electrodes are not formed on the light receiving surface of a silicon substrate, but P electrodes and N electrodes are formed on the back surface thereof.

  In a back electrode type solar cell, since there is generally no electrode on the light receiving surface, there is no shadow loss due to the electrode, and a higher output is obtained compared to a solar cell having electrodes on the light receiving surface and the back surface of the silicon substrate. Can be expected.

  For this reason, it has been proposed that the connection of the solar battery cells can be facilitated and cell cracking can be reduced by connecting the back electrode type solar battery cells using a wiring substrate in which wiring is formed on an insulating base material. (For example, refer to Patent Document 1).

JP 2005-340362 A

The use of a wiring board has been proposed to facilitate the connection of solar cells, but mass production has not been achieved. As a wiring board used in the semiconductor field, a wiring pattern is mainly formed on a hard substrate or a polyimide film on which a wiring pattern is formed by a copper foil on a glass epoxy substrate having a small thermal shrinkage rate. There is a flexible substrate. However, glass epoxy substrates and polyimide films used for these wiring boards are very expensive because 1 m ² or more is required per solar cell module material. This is a major factor that does not lead to mass production.

  Therefore, it is conceivable to use a cheaper material, but the cheap material generally has a problem in heat resistance. In the process of manufacturing the solar cell module, the wiring substrate is heated in the process of connecting the solar cell and the wiring substrate and the step of sealing the solar cell module with the weather-resistant sealing material, and is exposed to a temperature of at least about 150 ° C. May be.

  For example, when a PET film having a tenth of the price is used instead of a polyimide film, the dimensional change of the polyimide film is 0. Whereas it is 1% or less, the PET film may shrink by several%, and there is a high possibility that a deviation occurs between the electrode of the solar battery cell and the wiring of the wiring board, resulting in a defective module.

  In general, the electrode of a back electrode type solar cell is denser and has a finer pitch, and higher solar cell characteristics can be expected. However, considering the thermal shrinkage of the film, it is difficult to design an electrode with a finer and finer pitch. There arises a problem that the battery characteristics cannot be exhibited.

  Therefore, in view of the above problems, the present invention enables electrode design with a fine pitch even in a configuration in which solar cells are connected using a wiring substrate made of various resin materials whose thermal shrinkage rate is not sufficiently low. It aims at providing the solar cell module which exhibits a high solar cell characteristic, and its manufacturing method.

As a result of diligent investigations to achieve the above object, the present inventors have usually made a resin film produced by a biaxial stretching method in the MD direction (winding direction) and TD direction when being produced while being rolled up. A difference of several to several tens of times occurs in the heat shrinkage ratio (perpendicular to MD). For example, in the case of a general inexpensive PET film, the electrode pattern is finely designed considering that it is about 2% in the MD direction and about 0.2% in the TD direction with respect to heat treatment at 150 ° C. for 30 minutes. The inventors have found that a wiring board having a sufficiently small influence of thermal shrinkage can be manufactured by setting the direction with a small margin as the TD direction, and the present invention has been achieved. That is, the present invention is a solar cell module that electrically connects backside electrode type solar cells adjacent to each other using a wiring board in which a wiring pattern is formed on a film-like resin base material. by comparing the pitch of the wiring pattern in the first direction based on the second direction perpendicular to the pitch of the wiring pattern in the second direction, the direction to be smaller pitch, of the resin base material It is characterized by the TD direction being a direction perpendicular to the winding direction during film production.

  According to this configuration, in the wiring pattern formed on the film-like resin base material, the longitudinal direction of the plurality of wirings to be formed is the first direction, and the width direction in which the plurality of wirings are provided is the second direction. By adopting the TD direction of the resin base material having a small heat shrinkage rate in the second direction, it is possible to construct a wiring pattern in which the influence of the heat shrinkage is suppressed. Therefore, it is possible to obtain a solar cell module including a wiring board that is created using various resin materials whose heat shrinkage rate is not sufficiently low.

  Moreover, this invention is the solar cell module of the said structure, The said resin base material is a biaxially stretched resin film, It is characterized by the above-mentioned. According to this configuration, a resin suitable for a wiring board can be selected and used from many resin materials that are usually manufactured by a biaxial stretching method.

  In the solar cell module having the above-described configuration, the present invention is characterized in that the film is a polyester film. According to this structure, the wiring board of a solar cell module can be manufactured using an inexpensive and mass-produceable resin material.

  Moreover, this invention is a solar cell module of the said structure, The said film contains either polyethylene terephthalate PET or polyethylene naphthalate PEN, It is characterized by the above-mentioned. According to this configuration, even if the resin material has a large thermal contraction rate and is very inexpensive, it is possible to manufacture a wiring substrate having a sufficiently small thermal shrinkage effect by setting the width direction of the wiring substrate to the TD direction. it can.

Moreover, this invention is a manufacturing method of the solar cell module which electrically connects back electrode type photovoltaic cells mutually adjacent using the wiring board which formed the wiring pattern in the film-form resin base material, 1st Comparing the pitch of the wiring pattern in the first direction and the pitch of the wiring pattern in the second direction based on the direction and the second direction orthogonal to the direction, the direction having the smaller pitch is determined as the resin The resin base material is thermally shrunk when performing a heat treatment process with the TD direction being a direction perpendicular to the winding direction at the time of film production of the base material and the solar battery cell and the wiring substrate being stacked. It is characterized by.

  According to this configuration, in the wiring pattern formed on the film-like resin base material, the longitudinal direction of the plurality of wirings to be formed is the first direction, and the width direction in which the plurality of wirings are provided is the second direction. By adopting the TD direction of the resin base material having a small heat shrinkage rate in the second direction, it is possible to construct a wiring pattern in which the influence of the heat shrinkage is suppressed. For this reason, when the wiring substrate and the solar battery cell having a structure in which a large number of wirings are provided adjacent to each other in the second direction are overlapped and thermally contracted, the thermal contraction rate is reduced. Even when using various resin materials that are not sufficiently low, it is possible to obtain a method of manufacturing a solar cell module that prevents misalignment due to thermal shrinkage. In other words, even in a configuration in which solar cells are connected using a wiring substrate made of various resin materials whose heat shrinkage rate is not sufficiently low, a solar cell that enables electrode design at a fine pitch and exhibits high solar cell characteristics A method for manufacturing a module can be obtained.

  Moreover, the present invention is characterized in that, in the method for manufacturing a solar cell module having the above-described configuration, the temperature of the heat treatment step is set to 100 ° C. or higher and 180 ° C. or lower. According to this configuration, even if heat treatment is performed at the time of bonding, electrode connection, etc., the heating temperature is suppressed to 180 ° C. or less, and even if an inexpensive resin material having a low heat resistance temperature is used, displacement due to thermal contraction is prevented. can do.

  Further, the present invention provides a method for manufacturing a solar cell module having the above-described configuration, wherein a solder having a melting point of 180 ° C. or lower or a conductive adhesive that cures at 180 ° C. or lower is used for connection between the electrode on the solar cell side and the wiring board. It is characterized by use. According to this configuration, it is possible to reliably connect the electrode on the solar cell side and the wiring substrate while suppressing thermal contraction of the resin substrate at a heat treatment temperature of 180 ° C. or lower.

According to the present invention, the wiring pattern formed on the film-shaped resin substrate is divided into the wiring pattern pitch in the first direction and the wiring in the second direction based on the first direction and the second direction orthogonal thereto. Compared with the pitch of the pattern, the direction that becomes the smaller pitch is the TD direction that is perpendicular to the winding direction during film production of the resin base material, thereby suppressing the influence of thermal shrinkage A pattern can be constructed. Therefore, it is possible to obtain a solar cell module including a wiring board that is created using various resin materials whose heat shrinkage rate is not sufficiently low. In addition, by making the temperature of the heat treatment step when manufacturing this solar cell module 100 ° C. or more and 180 ° C. or less, even when using various inexpensive resin materials having a low heat-resistant temperature, misalignment due to heat shrinkage is caused. A solar cell module including the prevented wiring board can be manufactured.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic explanatory drawing of a photovoltaic cell, (a) shows a cross-sectional model, (b) is a top view which shows the photovoltaic cell in which the linear electrode pattern was formed, (c) is a dot It is a top view which shows the photovoltaic cell in which the electrode pattern of a shape was formed, (d) is a top view which shows the photovoltaic cell in which the comb-tooth shaped electrode pattern was formed. It is a top view which shows an example of a wiring board. The example of 1st embodiment of a photovoltaic cell is shown, (a) is the cross-sectional schematic diagram, (b) is a top view. It is a top view which shows the other example of a wiring board. An example of the solar cell module which concerns on this invention is shown, (a) is a top view, (b) is a cross-sectional schematic diagram. It is sectional drawing which shows the principal part structure of the semi-finished state before mounting | wearing with the frame and terminal box of the solar cell module which concerns on this invention. It is sectional drawing which shows the principal part structure of the completion state of the solar cell module which concerns on this invention.

  Embodiments of the present invention will be described below with reference to the drawings. 1A and 1B are schematic explanatory views of a solar battery cell, where FIG. 1A is a schematic cross-sectional view, FIG. 1B is a plan view showing a solar battery cell on which a line-shaped electrode pattern is formed, and FIG. ) Is a plan view showing a solar cell in which a dot-like electrode pattern is formed, and (d) is a plan view showing the solar cell in which a comb-like electrode pattern is formed. FIG. 2 is a plan view showing an example of a wiring board.

  The solar cell module includes a solar cell main body portion including a plurality of solar cells, a frame body that holds and integrates the periphery of the solar cell main body portion, and a terminal box that serves as an output portion of power generated by the solar cell main body portion And an output cable connected to the terminal box, and a solar cell sealing material such as translucent glass or a light-receiving surface protection plate made of a plastic material, sheet-like ethylene vinyl acetate, in order from the surface , Monocrystalline silicon, polycrystalline silicon, amorphous silicon, compound semiconductor, and other solar cells sealed in this solar cell encapsulant, and lamination of a back film that protects the solar cell encapsulant from the back surface The body is integrated into the frame body.

  The solar cell module is a string in which a plurality of solar cells are electrically wired by an interconnector, and a glass substrate with electrodes formed thereon are set in series / parallel, and a light-receiving surface protection plate and a back film on the back side And sealed with a translucent resin, and a frame is attached to the periphery. The solar battery cell of this embodiment is a back electrode solar battery cell 10 in which both the N electrode and the P electrode are on the back surface side, and has a configuration as shown in the schematic cross-sectional view of FIG. A silicon substrate 1, an antireflection film 2 formed on the light receiving surface of the silicon substrate 1, an N + layer 3 and a P + layer 4 formed on the back surface of the silicon substrate 1, a passivation film 7 formed on the back surface, N The electrode 5 and the P electrode 6 are provided. In addition, another passivation film may be formed between the silicon substrate 1 and the antireflection film 2.

  The antireflection film 2 and the passivation film 7 can be formed from, for example, a silicon nitride film or a silicon oxide film.

  The electrode pattern provided on the back side is a line-shaped electrode pattern as shown in FIG. 1B, a dot-shaped electrode pattern as shown in FIG. 1C, and a comb-like electrode pattern as shown in FIG. A solar cell 10A in which a line-shaped electrode pattern including a N-electrode 5a and a P-electrode 6a formed in a line shape is formed, a N-electrode 5b and a P-electrode formed in a dot shape, respectively. The solar battery cell 10B is provided with a dot-like electrode pattern having 6b, and the solar battery cell 10C is provided with a comb-like electrode pattern having N-electrodes 5c and P-electrodes 6c. Next, a wiring board to be mounted for connecting a plurality of electrodes of a plurality of solar cells 10 (10A, 10B, 10C) and taking out an electromotive force will be described.

  A wiring board means what formed the desired wiring pattern on the insulating board, and there exist what uses a hard board | substrate and a film board as an insulating board | substrate. In the present embodiment, a wiring board using a film manufactured by a biaxial stretching method is used.

  For example, this wiring board is made by bonding an insulating film as a base material and a metal foil using an adhesive, etc., forming a protective resist on the surface of the metal foil in a desired shape, and then etching the exposed metal foil By processing and removing the resist, a wiring board having a desired wiring pattern is formed. At this time, by determining the orientation of the film in accordance with the wiring pattern to be formed, a wiring board that is resistant to thermal shrinkage can be manufactured.

  In general, the film is produced by stretching the melted resin base material in a roll shape in a longitudinal direction (winding direction: MD direction) and a lateral direction (TD direction: a direction orthogonal to the MD direction) to obtain a uniform thickness. It is carried out by a biaxial stretching method for producing a film. As a feature of this method, since stress tends to remain in the MD direction, when shrinking by heating, it tends to shrink in the MD direction, and the thermal contraction rate may be several to several tens of times that in the TD direction. That is, the heat shrinkage rate in the TD direction of the resin base material is small, and the heat shrinkage rate in the MD direction is large.

  Therefore, as a resin base material of a flexible wiring substrate used in the semiconductor field, a polyimide film having excellent heat resistance that hardly changes in shape even when heated to tens of degrees Celsius is used. However, the polyimide film is very expensive, and when used as a wiring board of a solar cell module, it is difficult to mass-produce it considering that an area equivalent to the module area is required.

  On the other hand, polyester films such as PET (polyethylene terephthalate) and PEN (polyethylene naphthalate) are inexpensive because they are widely used for general purposes as packaging materials and the like. There are some things. However, the polyester-based film is greatly inferior in heat resistance as compared with the polyimide film, and may be used as a base material for a wiring board, but is limited to applications where no heat is applied. For example, in the case of a general PET film alone, the heat shrinkage rate is known to be about 2% in the MD direction and about 0.2% in the TD direction with respect to heat treatment at 150 ° C. for 30 minutes. Yes. Actually, since the metal foil is bonded, the shrinkage rate is smaller than the above value, but the shrinkage rate in the MD direction is still larger than that in the TD direction. Further, the specific shrinkage rate varies depending on the wiring pattern.

  When using a wiring board for a solar cell module, at the time of manufacturing the module, heating at at least 100 ° C. or more is required in both the connection with the solar cell and the sealing of the solar cell module. Moreover, since discoloration, modification, and deformation occur in a general PET resin, the processing temperature needs to be 180 ° C. or less. The same can be said with respect to PEN and other polyester films, although there are some differences. Therefore, in an application where a wiring board is used for a solar cell module, a polyester film is not used as a base material for the wiring board in the semiconductor field because of the problem of heat shrinkage. However, in solar cells, there is no need to use dense and complicated wiring patterns in both the vertical and horizontal directions, as in semiconductors, but a simple pattern as will be described later, and the direction where high accuracy is required is limited to one direction. Therefore, it is possible to use the pattern by forming the direction in which the high accuracy is required as the TD direction of the resin base material and the other as the MD direction. By doing in this way, an inexpensive polyester film can be used for a wiring board, As a result, mass production of a solar cell module is attained.

  FIG. 2 shows an example of a wiring board. This wiring board is a comb in which the wiring is formed corresponding to the electrode provided in the solar cell 10A in which the line-shaped electrode pattern is formed or the solar cell 10B in which the dot-shaped electrode pattern is formed. A wiring board 20 in which tooth-shaped P wiring and N wiring are formed so as to face each other (even if the cell electrode is comb-shaped), a plurality of (for example, twelve) wiring boards can be installed. When the solar cells are installed, connection wirings 9a to 9m are provided for connecting these cells in series. It is preferable that the wiring (P wiring and N wiring) formed corresponding to the electrode provided in the solar battery cell has a width equal to or greater than the width of the electrode. Wiring as a solar cell module is performed by connecting the electrodes of the solar battery cells and the wiring of the wiring board so as to overlap each other. By overlapping the electrodes and the wiring in this manner, the electric resistance when collecting the electricity generated in the solar cell can be reduced, and high solar cell characteristics can be obtained.

  Here, for example, a low melting point solder or a low temperature curing type conductive adhesive is used to connect the wiring of the wiring board and the electrode of the solar battery cell so that the heating temperature for the connection is suppressed to 180 ° C. or lower. Yes. In this case, if a polyester-based film such as PET or PEN is used as the resin substrate of the wiring board, even if the processing temperature is a relatively low temperature of 180 ° C. or less, positional displacement occurs due to thermal shrinkage and wiring defects are caused. There is a possibility. Therefore, since there is a high risk of contact between one electrode of the solar battery cell and the wiring connected to the other adjacent electrode, the X direction in the figure in which a large number of adjacent wirings are formed is the resin base material. A wiring board made of a resin base material having the TD direction and the Y direction being the MD direction will be used.

  As described above, the width direction of the wiring pattern in which a plurality of wirings are arranged adjacent to each other is the wiring substrate 20 having the TD direction of the resin base material. By adopting the TD direction of the resin base material and adopting the MD direction of the resin base material in a direction that can take a large pattern margin, a wiring pattern that is not affected by the heat shrinkage by preventing the positional deviation due to the heat shrinkage. Can be built.

  Next, a solar cell of a type that collects power to a bus bar electrode provided at the cell end via a comb-like finger electrode of the solar battery cell, and a wiring substrate that is connected via a connection wiring that comes into contact with the bus bar electrode A solar cell module consisting of: will be described with reference to FIGS.

  A solar battery cell 10C shown in FIG. 3A is a back electrode type solar battery in which both an N electrode 5 and a P electrode 6 are formed on the back surface. For example, an N type silicon substrate 1 and light reception of the silicon substrate 1 An antireflection film 2 formed on the surface, an N + layer 3 and a P + layer 4 formed on the back surface of the silicon substrate 1, a passivation film 7 formed on the back surface, an N electrode 5, and a P electrode 6. ing. Moreover, as shown in FIG.3 (b), the N electrode 5 formed in the photovoltaic cell 10C of this embodiment is the finger N electrode 5c, and the P electrode 6 is the finger P electrode 6c, These are comb-tooth shape. The bus bar N electrode 50 and the bus bar P electrode 60 are formed at the cell end.

  An example of the wiring board 21 used corresponding to the solar battery cell 10C is shown in FIG. The wiring of the wiring board used here is a connection wiring 9 (9a) that forms a wiring pattern for connecting the bus bar N electrode 50 and the bus bar P electrode 60 of the adjacent solar battery cells in series and a wiring pattern for connecting the solar battery strings. ~ 9m).

  By connecting the bus bar electrodes (the bus bar N electrode 50 and the bus bar P electrode 60) of the solar battery cells to the connection wiring 9 (9a to 9m), wiring as a solar battery module is performed. That is, the current is collected only by the finger electrodes of the solar battery cells, and the current is collected by the bus bar electrodes at the cell ends. In this way, only the bus bar portion needs to be overlaid on the connection wiring 9 of the wiring board, and thus it is necessary to devise a method for reducing the resistance of the finger electrode so as not to cause loss in the finger electrode. It is easy to align.

  In this case, the bus bar electrode and the connection wiring can be connected to each other by using the low melting point solder or the low temperature curing type conductive adhesive described above, so that the heating temperature for the connection can be suppressed to 180 ° C. or lower. At this time, if the base material of the wiring board is a polyester film such as PET or PEN, even if the treatment is performed at 180 ° C. or less, positional displacement may occur due to thermal shrinkage, resulting in wiring failure. Therefore, it is preferable to use the wiring substrate 21 that has a high possibility of coming into contact with the end portion of the finger electrode and in which the Y direction in the drawing is the TD direction of the resin base material.

  As described above, by using the wiring substrate 21 in which the direction with a high design possibility and a small design margin is the TD direction of the resin base material, positional displacement is prevented by thermal shrinkage and is not affected by thermal shrinkage. A wiring pattern can be constructed.

  After mounting and connecting the wiring substrate 21, it is sandwiched between a light-transmitting sealing material such as EVA (ethylene / vinyl / acetate), a light-transmitting substrate such as glass, and a weather-resistant film, and subjected to heat vacuum bonding and annealing. The module is sealed, and a solar cell module is completed by attaching a terminal box for taking out electricity to the frame and the outside.

  As described above, from the electrode pattern of the solar cell and the wiring pattern shape of the wiring board, the direction with the small design margin should be the direction with the small thermal shrinkage rate of the resin base material, and the design margin should be small and the error should be kept small. By matching the direction in which the heat shrinkage rate of the resin base material is small in a certain direction, it is possible to construct a wiring pattern that suppresses the effect of heat shrinkage, and using an inexpensive resin material that does not have a sufficiently low heat shrinkage rate A solar cell module provided with the produced wiring board can be obtained.

  Depending on the type of sealing material used in the heat-vacuum pressure bonding and annealing process, it is generally heated at 120 to 180 ° C. for about 10 to 60 minutes, so when a polyester film is used for the wiring board, There is a possibility that the position difference between the solar battery cell and the wiring board may occur due to the contraction due to. Even in this case, it is possible to prevent the occurrence of module failure due to misalignment by setting the direction of small design margin as the TD direction of the resin base material.

  Thus, the wiring pattern used in the solar cell module is simple and the same pattern for all cells. Therefore, the direction with a small design margin is the TD direction of the base film, and the direction with a margin is the MD direction. By doing so, it is possible to use a polyester film such as PET or PEN which is very inexpensive but has a large thermal shrinkage rate.

(Example)
As an example, a solar battery module M was manufactured by using the solar battery cell 10A on which the linear electrode pattern shown in FIG. 1 was formed and the wiring substrate 20 shown in FIG. As shown in FIG. 1A, in the solar cell 10A, N + layers 3 and P + layers 4 are alternately formed in a line shape on the back surface side of the solar cell, and an antireflection film 2 made of, for example, a silicon nitride film is formed on the light receiving surface. A passivation film 7 is formed on the back side, and an N electrode 5 and a P electrode 6 are formed on the N + layer and the P + layer, respectively. The solar battery cell 10A having this configuration can be manufactured by a known method. Here, the electrode of the solar battery cell 10A is a fired electrode mainly composed of silver, in which line-shaped N electrodes 5a and P electrodes 6a are alternately formed, and the distance between the N electrode 5a and the P electrode 6a. Was 0.5 mm. The width of each electrode was set to 0.2 mm for both electrodes. Further, solder (Sn—Bi solder) H was coated on the surface of the electrode.

  Next, a 25 μm-thick PET film was used as the base material for the wiring substrate 20 and bonded to a 35 μm copper foil using an adhesive, and then a protective resist was formed and etched into a desired shape. The wiring board 20 is provided with comb-like N wirings and P wirings, N type wirings electrically connected to the N type electrodes of the back electrode type solar cells, and adjacent solar cells. A connection wiring is formed to electrically connect the P-type wiring electrically connected to the P-type electrode of the cell. In addition, wiring is also formed so that the strings are connected in series.

  Here, the width of the wiring overlapping the electrode of the solar battery cell was set to 0.35 mm. The reason why the width of the wiring is wider than the width of the electrode of 0.2 mm is to prevent the cell characteristics from being deteriorated due to the electric resistance when collecting the current generated in the solar battery cell. The distance to the opposite polarity electrode is 0.15 mm. In addition, the distance between the location corresponding to the comb-shaped N wiring and P wiring bus bar and the tip of the solar cell electrode having the opposite polarity was set to 0.5 mm. In addition, the wiring board was manufactured with the X direction of the module having a small design margin as the TD direction of the base material.

  Subsequently, as shown in FIG. 5 (a), twelve solar cells 10A (10a to 10l) are placed on the wiring board, and the solar battery cell is prevented from moving using a UV curable adhesive. Temporarily fixed. Then, as shown in FIG. 5B, the N electrode 5a and the N wiring 91 and the P electrode 6a and the P wiring 92 were electrically connected by reflow soldering. This reflow soldering is a soldering method in which solder H is coated in advance on a connection portion, and an electronic component is placed thereon and then heated. In this embodiment, the peak temperature to be heated is 150 ° C. It set so that it might become.

  Next, as shown in FIG. 6, an EVA film as a sealing material is installed on the light receiving surface side and the back surface side, a glass substrate 11 is installed on the light receiving surface side, and a weather resistant film 12 is installed on the back surface side. The solar cell module was sealed by heat-vacuum pressure bonding with a laminator and further annealed. The heating temperature and treatment time in each step were 5 minutes at 130 ° C. for the laminator and 40 minutes at 140 ° C. for the annealing treatment.

  Through the steps as described above, as shown in FIG. 7, an aluminum frame 30 is attached to the periphery of the module, a terminal box 8 is attached to take out electricity to the outside, and two solar cell modules M (MA And MB) completed. The electricity generated by the solar cell module M can be taken out via the output cable 81.

(Comparative example)
As a comparative example, the TD direction of the PET film that is the base material of the wiring board is set as the Y direction, the MD direction is set as the X direction of the board shape, and the reverse direction is set. Two units, Ma and Mb, were produced.

  The solar cell modules MA and MB produced as examples and the solar cell modules Ma and Mb produced as comparative examples were subjected to a confirmation test of presence / absence of failure mode and the number of defective cells. The results are shown in Table 1.

  The cause of the failure that occurred in the comparative example was that two of the 12 cells of the comparative examples Ma and Mb were short-circuited due to misalignment. The two examples MA and MB can be produced without any problem due to misalignment, and shrinkage due to heat by setting the direction with a small dimensional margin and a small design margin as the TD direction of the base film. It was confirmed that it was difficult to be affected by

  As described above, the resin base material of the wiring board is defined as a direction in which the thermal contraction rate of the resin base material is small, from the shape of the electrode pattern of the solar battery cell and the wiring pattern of the wiring board, with a direction with a small thermal shrinkage rate of the resin base material. By making the width direction in which a plurality of wirings of the pattern are arranged side by side as the TD direction of the resin base material, the pitch is relatively simple and the wiring pattern of the solar cell connection that is a repetition of the same pattern is fine pitch By adopting the TD direction of the resin base material in the width direction to be wired and adopting the MD direction of the resin base material in the direction that can take a large pattern margin, a wiring pattern that is not affected by thermal shrinkage is constructed. be able to.

  For this reason, the solar cell module according to the present invention has a fine pitch electrode design even in a configuration in which solar cells are connected using a wiring board made of various inexpensive resin materials whose thermal shrinkage rate is not sufficiently low. This enables a solar cell module that exhibits high solar cell characteristics.

  Moreover, since the manufacturing method of the solar cell module according to the present invention manufactures the solar cell module having the above configuration at a heat treatment step temperature of 100 ° C. or higher and 180 ° C. or lower, even if an inexpensive resin material having a low heat-resistant temperature is used, A positional shift can be prevented by heat shrinkage, and a manufacturing method in which defective products are not generated is obtained.

  Therefore, according to the present invention, in a solar cell module for electrically connecting back electrode solar cells adjacent to each other using a wiring board in which a wiring pattern is formed on a film-like resin base material, a film-like resin is used. In the wiring pattern formed on the substrate, the longitudinal direction of the plurality of wirings to be formed is defined as the first direction, the width direction in which the plurality of wirings are provided is defined as the second direction, and the heat shrinkage rate is increased in the second direction. By adopting the TD direction of a small resin substrate, it is possible to construct a wiring pattern that suppresses the influence of thermal shrinkage. Therefore, it is possible to obtain a solar cell module including a wiring board that is created using various resin materials whose heat shrinkage rate is not sufficiently low. In addition, the temperature of the heat treatment process when manufacturing the solar cell module is set to a manufacturing method of 100 ° C. or higher and 180 ° C. or lower, thereby preventing misalignment due to thermal shrinkage even when using an inexpensive resin material having a low heat resistance temperature. A solar cell module including the printed wiring board can be manufactured.

  The solar cell module according to the present invention is a solar cell module provided with a wiring board made using various inexpensive resin materials whose heat shrinkage rate is not sufficiently low, and is therefore suitable for the solar cell field that requires mass production. Applicable.

DESCRIPTION OF SYMBOLS 1 Silicon substrate 2 Antireflection film 3 N + layer 4 P + layer 5 N electrode 6 P electrode 7 Passivation film 9 Connection wiring 10 Solar cell 20 Wiring substrate 21 Wiring substrate 30 Frame H Solder M Solar cell module

Claims (7)

A solar cell module for electrically connecting back electrode solar cells adjacent to each other using a wiring substrate in which a wiring pattern is formed on a film-like resin base material,
Comparing the pitch of the wiring pattern in the first direction and the pitch of the wiring pattern in the second direction based on the first direction and the second direction orthogonal to the first direction, the direction with the smaller pitch is A solar cell module having a TD direction which is a direction orthogonal to a winding direction at the time of film production of the resin substrate. The solar cell module according to claim 1, wherein the resin base material is a biaxially stretched resin film. The solar cell module according to claim 1, wherein the film is a polyester film. The solar cell module according to claim 3, wherein the film contains either polyethylene terephthalate PET or polyethylene naphthalate PEN. Using a wiring board in which a wiring pattern is formed on a film-shaped resin base material, a solar cell module manufacturing method for electrically connecting back electrode solar cells adjacent to each other,
Based on the first direction and the second direction orthogonal thereto, the pitch of the wiring pattern in the first direction is compared with the pitch of the wiring pattern in the second direction, and the direction having the smaller pitch is determined. The resin base material is heated when the heat treatment step is performed with the TD direction being a direction orthogonal to the winding direction at the time of film production of the resin base material and the solar battery cell and the wiring substrate being stacked. The manufacturing method of the solar cell module characterized by shrinking | contracting. The method for manufacturing a solar cell module according to claim 5, wherein the temperature of the heat treatment step is set to 100 ° C. or higher and 180 ° C. or lower. 7. The solar according to claim 5, wherein a solder having a melting point of 180 ° C. or lower or a conductive adhesive that cures at 180 ° C. or lower is used for connection between the electrode on the solar battery cell and the wiring board. Manufacturing method of battery module.

Images