JP2005340362A - Solar cell and solar cell module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solar cell capable of being inexpensively manufactured with a greater FF (Fill Factor) value, and to provide a solar cell module using the solar cell. <P>SOLUTION: In the solar cell and the solar cell module using the solar cell, the solar cell includes a solar cell wafer 17 where pluralities of p electrodes 6 and n electrodes 5 are formed respectively in a dot shape on one surface of a semiconductor substrate 1; and a wiring board where a p wiring 14 and an n wiring 15 are formed, electrically insulated from each other on one surface of an insulating substrate 16. One surface of a wiring board 18 is installed on one surface of the solar cell wafer 17, and the p electrodes 6 are electrically connected with each other through the p wiring 14 and the n electrodes 5 are electrically connected with each other through the n wiring 15. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a solar battery cell and a solar battery module, and more particularly to a solar battery cell having a large FF (Fill Factor) value and capable of being manufactured at low cost, and a solar battery module using the solar battery cell.

In recent years, development of clean energy has been desired due to the problem of depletion of energy resources and global environmental problems such as an increase in CO _{2 in} the atmosphere. In particular, a solar cell module configured by connecting a plurality of solar cells. The solar power generation used has been developed and put into practical use as a new energy source, and is on the path of development.

  Conventionally, a solar cell constituting a solar cell module has a conductivity type opposite to the conductivity type of the silicon substrate on the surface (light receiving surface) on the side where sunlight enters among the surfaces of a single crystal or polycrystalline silicon substrate, for example. A pn junction is formed by diffusing impurities to be formed, and electrodes are formed on the light receiving surface of the silicon substrate and the back surface on the opposite side. It is also common to increase the output by the back surface field effect by diffusing impurities of the same conductivity type as the silicon substrate at a high concentration on the back surface of the silicon substrate.

  In addition, so-called back junction solar cells have been developed in which electrodes are not formed on the light receiving surface of a silicon substrate, but electrodes of different conductivity types are formed only on the back surface of the silicon substrate. In the back junction solar cell, since power can be taken out only from the back side of the silicon substrate on which the electrode is formed, the electrode is a back junction solar cell and a solar cell module in which a plurality of these are connected. Very important from an output perspective.

  FIG. 11 shows a schematic cross-sectional view of an example of a conventional back junction solar cell. In this conventional back junction solar cell, for example, an antireflection film (not shown) is formed on the light receiving surface of an n-type silicon substrate 101, and an n + layer 105 and a p + layer are formed on the back surface of the silicon substrate 101. 106 are alternately formed along the back surface at predetermined intervals. A p electrode 111 is formed on the p + layer 106, and an n electrode 112 is formed on the n + layer 105. When sunlight is incident on the light receiving surface of the back junction solar cell, carriers generated in the vicinity of the light receiving surface of the silicon substrate 101 reach the pn junction formed on the back surface, and current is supplied to the p electrode 111 and the n electrode 112 as current. Collected and taken out to be output of the solar battery cell.

  Moreover, the typical top view of an example of the back surface of the conventional back junction type photovoltaic cell is shown in FIG. As shown in FIG. 12, in this conventional back junction solar cell, from the viewpoint of improving the output of the solar cell, a p-electrode 111 and an n-electrode 112 are respectively disposed inside the back surface of the silicon substrate 101. It is formed in a comb shape so as to cover.

FIG. 13 shows a flowchart of an example of a manufacturing process of a conventional back junction solar cell. First, in step 1a (S1a), an n-type single crystal silicon substrate is prepared. In step 2a (S2a), SiOx films are deposited on both surfaces of the silicon substrate by using an APCVD method (atmospheric pressure CVD method). In step 3a (S3a), a p + layer is formed by performing BBr ₃ vapor phase diffusion after opening a comb-shaped pattern on the back surface of the silicon substrate by a photo-etching method. Subsequently, in step 4a (S4a), after the acid-resistant tape is attached to the light receiving surface of the silicon substrate, the back surface is cleaned with HF (hydrogen fluoride). Then, after removing the acid-resistant tape on the light receiving surface, a SiOx film is deposited again on the back surface. Next, in step 5a (S5a), a comb-shaped pattern is opened by a photo-etching method so as to face the p + layer between the comb-shaped p + layers on the back surface of the silicon substrate, and then POCl ₃ The n + layer is formed by vapor phase diffusion so that the p + layer comb teeth and the n + layer comb teeth face each other. In step 6a (S6a), after cleaning the entire surface of the silicon substrate with HF, a SiN film is deposited on the light receiving surface of the silicon substrate by plasma CVD.

  Next, in step 7a (S7a), as shown in FIG. 14, the p-electrode 111 is placed within the range of the p + layer formed on the back surface of the silicon substrate 101, and the n-electrode 112 is placed within the range of the n + layer. It is formed by screen printing in the form of dots and then firing. Here, a silver paste is used as the screen printing material, and the p-electrode 111 and the n-electrode 112 are formed by drying the screen-printed silver paste and baking it in an oxidizing atmosphere.

  Thereafter, in step 8a (S8a), by forming a linear connection electrode pattern that electrically connects the dotted p-electrode 111 and the n-electrode 112 by screen printing using a silver paste, and then firing, As shown in FIG. 15, connecting electrodes 113a and 113b made of silver are formed. In step 9a (S9a), the p-electrode 111, the n-electrode 112, and the coupling electrodes 113a and 113b are dried after being dipped in the flux, dipped in a solder bath, and solder-coated. Thereafter, these electrodes are washed and then dried to complete a solar battery cell.

Further, using a plurality of solar cells thus obtained, as shown in FIG. 16, the connection electrode 113a of one solar cell and the connection electrode 113b of another solar cell among the plurality of solar cells Are electrically connected by connection electrodes 107 soldered to these electrodes to produce a solar cell module. And this solar cell module can also be stuck on a glass substrate between EVA (ethylene vinyl acetate) resin.
U.S. Pat. No. 4,133,697 US Pat. No. 5,185,042

  However, in the conventional solar battery cell and solar battery module obtained as described above, the point-like p-electrode and n-electrode formed by firing the silver paste and the silver paste are fired. There was a problem that the FF value could not be improved because the contact resistance with the connecting electrode was large. Moreover, since the amount of the silver paste used when manufacturing one photovoltaic cell also increases, there also existed a problem that it cannot manufacture cheaply.

  Therefore, an object of the present invention is to provide a solar cell having a large FF (Fill Factor) value and capable of being manufactured at low cost, and a solar cell module using the solar cell.

  In the present invention, a solar cell wafer in which a plurality of p-electrodes and n-electrodes are formed in a dot shape on one surface of a semiconductor substrate, and p-wire and n-wire are electrically insulated from each other on one surface of an insulating substrate. A wiring substrate formed on one surface of the solar cell wafer, the p electrode being electrically connected by the p wiring, and the n electrode being electrically connected by the n wiring. It is a solar battery cell.

  Here, in the solar battery cell of the present invention, the p electrode and the n electrode are formed of a material containing silver, the p wiring and the n wiring are formed of a material containing copper, and the p electrode and the p wiring And the connection between the n electrode and the n wiring are preferably made via solder.

  Further, in the solar battery cell of the present invention, the p wiring and the n wiring are each formed in a comb shape including comb teeth, and the p wiring and the n wiring are installed with the respective comb teeth facing each other, It is preferable that the comb teeth of the p wiring and the comb teeth of the n wiring are alternately arranged along one surface of the insulating substrate.

  In the solar cell of the present invention, it is preferable that the p electrode and the n electrode are arranged in a line, and the arrangement line of the p electrode and the arrangement line of the n electrode are alternately arranged.

  Further, in the solar battery cell of the present invention, the insulating substrate can be transparent.

  Moreover, in the photovoltaic cell of this invention, it is preferable that the reflecting film is formed in the surface on the opposite side of the one surface of an insulating substrate.

  The present invention also includes a solar cell wafer in which a plurality of n electrodes are formed in the shape of dots on the light receiving surface of a semiconductor substrate, and a wiring substrate in which n wiring is formed on one surface of an insulating substrate, One surface of the wiring substrate is installed on one surface of the battery wafer, the n electrodes are electrically connected by the n wiring, and the insulating substrate is a transparent solar cell.

  The present invention also includes a solar cell wafer in which a plurality of p-electrodes are formed in the shape of dots on a light receiving surface of a semiconductor substrate, and a wiring substrate in which p wiring is formed on one surface of an insulating substrate, One surface of the wiring substrate is placed on one surface of the battery wafer, the p-electrodes are electrically connected by the p-wiring, and the insulating substrate is a transparent solar cell.

  Furthermore, the present invention provides a plurality of solar cell wafers in which a plurality of p-electrodes and n-electrodes are formed in a dot shape on one surface of a semiconductor substrate, p-wires, n-wires and these wires on one surface of an insulating substrate. A wiring substrate on which a connection electrode to be electrically connected is formed, and the p electrode of one solar cell wafer among the solar cell wafers is electrically connected to the p wiring, and the one solar cell wafer This is a solar cell module in which n electrodes of other solar cell wafers different from are electrically connected to n wiring.

  Here, in the solar cell module of the present invention, the p electrode and the n electrode are formed of a material containing silver, the p wiring and the n wiring are formed of a material containing copper, and the p electrode and the p wiring And the connection between the n electrode and the n wiring are preferably made via solder.

  In the solar cell module of the present invention, the p wiring and the n wiring are each formed in a comb shape including comb teeth, and are electrically connected to the p electrode and the n electrode of one solar cell wafer, respectively. It is preferable that the wiring and the n wiring are arranged with their respective comb teeth facing each other, and the comb wiring teeth of the p wiring and the comb teeth of the n wiring are alternately arranged along one surface of the insulating substrate. .

  ADVANTAGE OF THE INVENTION According to this invention, the FF (Fill Factor) value is large, the photovoltaic cell which can be manufactured cheaply, and a solar cell module using the same can be provided.

  Hereinafter, embodiments of the present invention will be described. In the drawings of the present application, the same reference numerals represent the same or corresponding parts. Further, in this specification, a surface on the side where sunlight enters the solar cell module is defined as a light receiving surface, and a surface on the opposite side of the light receiving surface and on which sunlight does not enter is defined as a back surface.

  In FIG. 1, typical sectional drawing of a preferable example of the photovoltaic cell of this invention is shown. In this solar cell, a plurality of p + layers 6 and n + layers 5 are formed on the back surface of a semiconductor substrate 1 such as a silicon substrate at intervals along the back surface. A solar cell wafer 17 in which a dotted p-electrode 11 is formed and a dotted n-electrode 12 is formed on the n + layer 5, a p-wiring 14 and an n-wiring 15 are formed on an insulating substrate 16. Wiring board 18. Then, the wiring substrate 18 is installed on the back surface of the solar cell wafer 17, the p wiring 14 is installed on the p electrode 11 via the solder 19, and the plurality of dotted p electrodes 11 are electrically connected, and n An n wiring 15 is installed on the electrode 12 via a solder 19, and a plurality of dot-like n electrodes 12 are electrically connected.

In FIG. 2, the flowchart of a preferable example of the manufacturing process of the photovoltaic cell of this invention is shown. First, in step 1 (S1), for example, an n-type single crystal silicon substrate is prepared as the semiconductor substrate 1. In step 2 (S2), SiOx films are deposited on both surfaces of the semiconductor substrate 1 by using an APCVD method (atmospheric pressure CVD method). Then, in step 3 (S3), a p + layer 6 is formed by carrying out BBr ₃ vapor phase diffusion after opening a comb-shaped pattern on the back surface of the semiconductor substrate 1 by photo etching. Subsequently, in step 4 (S4), after the acid-resistant tape is attached to the light receiving surface of the semiconductor substrate 1, the back surface is cleaned with HF (hydrogen fluoride). Then, after removing the acid-resistant tape on the light receiving surface, a SiOx film is deposited again on the back surface. Next, in step 5 (S5), a comb-shaped pattern is opened by photo-etching on the back surface of the semiconductor substrate 1 so as to face the comb-shaped p + layer 6 and then the comb-shaped pattern is formed by POCl ₃ vapor phase diffusion. The n + layer 5 is formed so that the comb teeth of the p + layer 6 and the comb teeth of the n + layer 5 face each other, and these comb teeth are alternately arranged along the back surface of the semiconductor substrate 1. In step 6 (S6), after cleaning the entire surface of the semiconductor substrate 1 with HF, a SiN film is deposited on the light receiving surface of the semiconductor substrate 1 by, for example, plasma CVD.

  Next, in step 7 (S7), as shown in the schematic plan view of FIG. 3, the p electrode 11 is placed in the range of the p + layer 6 formed on the back surface of the semiconductor substrate 1, and the range of the n + layer 5 is reached. The n-electrodes 12 are formed by screen printing in a plurality of dot shapes, and then firing. Here, from the viewpoint of improving sunlight reflection and conductivity, the p-electrode 11 and the n-electrode 12 are made of silver, and a silver paste is used as the screen printing material. Then, the p-electrode 11 and the n-electrode 12 made of silver are formed by drying the screen-printed p-electrode 11 and the n-electrode 12 and evaporating the solvent contained in the silver paste, followed by firing in an oxidizing atmosphere. Is done. Further, as shown in FIG. 3, the p electrode 11 and the n electrode 12 are arranged linearly, and the arrangement line of the p electrode 11 and the arrangement line of the n electrode 12 are respectively along the back surface of the semiconductor substrate 1. They are arranged alternately.

  In step 8 (S8), the p electrode 11 and the n electrode 12 are dipped in the flux and then dried. Thereafter, the p-electrode 11 and the n-electrode 12 are immersed in a solder bath, washed and dried, and the surface of the p-electrode 11 and the n-electrode 12 is coated with the solder 19 to form the solar cell wafer 17.

  Subsequently, in step 9 (S9), the wiring substrate 18 as shown in the schematic plan view of FIG. 4 in which the p wiring 14 and the n wiring 15 made of, for example, copper are formed on one surface of the insulating substrate 16 is formed. Prepared. Here, the wiring substrate 18 is formed such that the p wiring 14 and the n wiring 15 each have a comb shape including a plurality of comb teeth, and the p wiring 14 and the n wiring 15 are disposed with their comb teeth facing each other. ing. Then, comb teeth of the p wiring 14 and comb teeth of the n wiring 15 are alternately arranged along one surface of the insulating substrate 16. In this wiring substrate 18, for example, after forming a film made of copper on the entire surface of the insulating substrate 16, a part of the film made of copper is removed by etching to form the p wiring 14 and the n wiring 15. Produced. Here, the surface of the p wiring 14 and the n wiring 15 is coated with solder.

  And this wiring board 18 is installed on the back surface of the solar cell wafer 17, and p wiring 14 and n wiring 15 are installed on the p electrode 11 and the n electrode 12, respectively, as shown in the schematic plan view of FIG. Is done. Then, for example, by blowing hot air from the solar cell wafer 17 side to melt both solders and then cooling, a solar cell in which the solar cell wafer 17 and the wiring substrate 18 are integrated is completed.

  Here, from the viewpoint of improving the FF value, an aluminum film is used as a reflective film on the surface opposite to the side where the p wiring 14 and the n wiring 15 of the insulating substrate 16 shown in FIG. It can also be formed. In this case, since the sunlight reflected by the reflective film needs to pass through the insulating substrate 16, the insulating substrate 16 needs to be transparent.

  Thus, in the above, a plurality of dot-like p-electrodes 11 and n-electrodes 12 made of silver whose surfaces are coated with solder 19, p-wires 14 and n made of copper whose surfaces are also coated with solder 19. The wirings 15 are electrically connected to each other via solder 19. As a result, a p-electrode and an n-electrode made of pointed silver formed by firing a silver paste, and a connecting electrode made of silver also formed by firing the silver paste, which has caused a large contact resistance. Can be avoided. Therefore, the FF (Fill Factor) value of the solar battery cell of the present invention can be improved as compared with the conventional case. Moreover, since the amount of silver paste used for formation of a connection electrode can be reduced, it can manufacture at a cheaper cost than before. Furthermore, the reinforcement effect of the photovoltaic cell of this invention can also be acquired by using a wiring board.

  The schematic side view of FIG. 6 shows a schematic side view of another preferred example of the solar battery cell of the present invention. In solar cell wafer 17 of this solar cell, n + layer 5 is formed on the light receiving surface of semiconductor substrate 1 made of, for example, a p-type silicon substrate, and an antireflection film (not shown) is formed on n + layer 5. ) And an n-electrode 12 made of silver. A p + layer 6 is formed on the back surface of the semiconductor substrate 1, and a p-electrode 11 is formed on the entire back surface of the semiconductor substrate 1. Further, a wiring board 18 on which an n wiring 15 made of copper is formed is installed on the light receiving surface of the solar cell wafer 17, and the n wiring 15 and the n electrode 12 are electrically connected via a solder 19. ing.

  Here, the surfaces of the n electrode 12 and the n wiring 15 are respectively coated with solder 19, and the plurality of dot-like n electrodes 12 are fished on the n + layer 5 as shown in the schematic plan view of FIG. It is arranged in the shape of a bone (fish bone). Then, an n wiring 15 formed in a fishbone shape in advance on the wiring substrate 18 is installed on the n electrode 12 of the solar cell wafer 17, and hot air is blown from the solar cell wafer 17 side, for example, to both solders 19. Then, the solar cell wafer 17 and the wiring substrate 18 are integrated to complete the solar cell shown in FIG. Here, the insulating substrate 16 in the wiring substrate 18 is transparent, and sunlight incident from the wiring substrate 18 side passes through the transparent insulating substrate 16 and reaches the light receiving surface of the semiconductor substrate 1.

  Also in this solar cell, a plurality of dot-like n electrodes 12 made of silver whose surface is coated with solder 19 are respectively connected via solder 19 by n wiring 15 made of copper whose surface is coated with solder 19. Since it is electrically connected, the FF (Fill Factor) value of the solar battery cell can be improved as compared with the prior art. Moreover, like the above-described solar battery cell, the manufacturing cost of the solar battery cell can be reduced, and the reinforcing effect by the wiring board 18 can also be obtained. In this solar cell, an n electrode 12 is formed on the light receiving surface of the semiconductor substrate 1, and the n electrode 12 is electrically connected to the n wiring 15 of the wiring substrate 18. It goes without saying that a p-electrode may be formed on the p-electrode, and this p-electrode may be electrically connected to the p-wiring of the wiring board 18.

  In FIG. 8, the typical top view of a preferable example of the back surface of the solar cell module of this invention is shown. This solar cell module is electrically connected to the solar cell wafers 17a, 17b, 17c shown in FIG. 9 having the same configuration as the solar cell wafer shown in FIG. 1, and the p-electrode 11 on one surface of the insulating substrate 16 shown in FIG. The wiring board 18 in which the p wiring 14 to connect, the n wiring 15 which electrically connects the n electrode 12, and the connection electrode 20 which electrically connects these wiring are formed is included. Then, the p-electrode 11 of one solar cell wafer 17a among the solar cell wafers 17 is electrically connected to the p-wiring 14 of the wiring substrate 18, and another solar cell wafer 17b different from the one solar cell wafer 17a. N electrode 12 is electrically connected to n wiring 15. The p-electrode 11 of the solar cell wafer 17 b is electrically connected to the p-wiring 14 of the wiring substrate 18, and the n-electrode 12 of the solar cell wafer 17 c is electrically connected to the n-wiring 15.

  This solar cell module is manufactured as follows, for example. First, as shown in the schematic plan view of FIG. 9, the solar cell wafers 17a, 17b, and 17c formed as described above are arranged with their back surfaces facing upward. Next, as shown in the schematic plan view of FIG. 10, the p wiring 14 and the n wiring 15 made of comb-shaped copper face each other, and each comb tooth is an insulating substrate 16. The wiring substrate 18 is formed so as to be alternately arranged along one surface, and the connection electrode 20 that electrically connects the p wiring 14 and the n wiring 15 is formed on one surface of the insulating substrate 16. prepare. And this wiring board 18 is installed on the back surface of these solar cell wafers 17a, 17b, 17c, and p wiring 14 and n wiring 15 of wiring board 18 and p electrode 11 of solar cell wafers 17a, 17b, 17c and The n electrode 12 is electrically connected to each other through solder. Thereby, the solar cell module of the present invention shown in FIG. 8 is completed. In the present invention, the solar cell module can be attached to a substrate such as a glass substrate after being sandwiched between EVA resins.

  Thus, in the solar cell module of the present invention, the p-electrode 11 and the n-electrode 12 of the solar cell wafers 17a, 17b, and 17c formed in a dot shape are formed in advance on the wiring board 18 and the p-wiring 14 and n. They are electrically connected to the wiring 15 via solder. Thereby, even when the p-electrode 11 and the n-electrode 12 of the solar cell wafers 17a, 17b, and 17c are made of silver, the contact resistances of the p-electrode 11 and the p-wiring 14, and the n-electrode 12 and the n-wiring 15 are made higher than those of the conventional one. Can be reduced. Further, by using the wiring substrate 18 on which the connection electrodes 20 are previously installed, the electrical connection and configuration of the solar cell wafers 17a, 17b, and 17c can be simultaneously and easily formed.

  In the above, as the insulating substrate 16 of the wiring substrate 18, for example, a glass substrate, a glass epoxy substrate formed by immersing an epoxy resin in a nonwoven fabric made of glass fiber, a transparent polyester film (PET film), polyethylene naphthalate A film (PEN film), a polyimide film, or a polypropylene film can also be used.

  In the above description, the dot-like p-electrode 11 and the n-electrode 12 are each arranged in a straight line, but are not limited to a straight line and may be arranged in a line such as a curved line or a spiral.

  In the above, the insulating substrate 16 constituting the wiring board 18 is transparent from the viewpoint of transmitting sunlight, particularly when the wiring board 18 is installed on the light receiving surface of the solar cell wafer 17. preferable.

  In the above description, it is needless to say that n-type and p-type conductivity may be interchanged.

  Moreover, in the above, it is not necessary to coat the surface of the p electrode 11, the n electrode 12, the p wiring 14 and the n wiring 15, but from the viewpoint of improving the FF value, it is preferable to coat the solder.

  In the above description, it goes without saying that the p electrode 11 and the n electrode 12 may be made of a material other than silver, and the p wiring 14 and the n wiring 15 may be made of a material other than copper.

(Example 1)
The solar battery cell shown in FIG. 1 was manufactured as follows. First, a SiOx film of about 200 nm is formed on the light-receiving surface and the back surface of a semiconductor substrate 1 made of a flat n-type single crystal silicon substrate having a width of 125 mm, a length of 125 mm, and a thickness of 240 μm etched using an alkaline solution by an APCVD method. Was deposited. Next, a comb-shaped window having a width of 250 μm is opened on the back surface of the semiconductor substrate 1 by photo-etching, and BBr ₃ vapor phase diffusion is performed at 970 ° C. for 50 minutes to form a p + layer 6 of about 30Ω / □. Formed. Subsequently, after the acid-resistant tape was attached to the light receiving surface of the semiconductor substrate 1, the back surface was cleaned with HF (hydrogen fluoride). Then, after the acid-resistant tape on the light receiving surface of the semiconductor substrate 1 was peeled off, an SiOx film was deposited on the back surface by about 200 nm again by the APCVD method. Next, a comb-shaped pattern having a width of 250 μm is opened on the back surface of the semiconductor substrate 1 so as to face the comb-shaped p + layer 6 by a photoetching method, and then POCl ₃ vapor phase diffusion is performed at 830 ° C. for 20 minutes. A comb-shaped n + layer 5 of about 40Ω / □ was formed. Here, the p + layer 6 and the n + layer 5 are alternately arranged along the back surface of the semiconductor substrate 1 so that the comb teeth of the p + layer 6 and the comb teeth of the n + layer 5 face each other. Formed to be arranged. Then, after cleaning the entire surface of the semiconductor substrate 1 with HF, a SiN film having a thickness of 700 nm was deposited on the light receiving surface of the semiconductor substrate 1 by plasma CVD.

  Next, as shown in FIG. 3, a plurality of dot-like p-electrodes 11 are formed in the range of the p + layer 6 formed on the back surface of the semiconductor substrate 1, and a plurality of dot-like p-type electrodes in the range of the n + layer 5 Each n-electrode 12 was screen-printed using a silver paste. Here, the diameters of the upper surfaces of the p electrode 11 and the n + layer 5 were 150 μm. Thereafter, the screen-printed silver paste was dried at a temperature of about 150 ° C. and then fired in an oxidizing atmosphere at about 620 ° C. for about 1 to 2 minutes. Thereafter, the p electrode 11 and the n electrode 12 were immersed in the flux and then dried. And it immersed in the solder bath of about 200 degreeC, the solder 19 was coated, the p electrode 11 and the n electrode 12 were wash | cleaned and dried, and the solar cell wafer 17 was formed.

  On the other hand, on one surface of an insulating substrate 16 made of a flat glass epoxy substrate having a width of 150 mm, a length of 150 mm and a thickness of 1.6 mm, a p wiring 14 and an n wiring made of copper having a surface coated with solder are formed. A wiring board 18 shown in FIG. Then, as shown in FIG. 5, the solar cell wafer 17 is superposed on the alignment marker of the wiring board 18 preheated to 90 ° C., and hot air is blown from the solar cell wafer 17 side to melt both solders. After cooling, the solar battery cell shown in FIG. 1 in which the solar battery wafer 17 and the wiring board 18 were integrated was completed.

  A current-voltage curve of this solar battery cell was prepared, and the short-circuit current Isc (mA), the open-circuit voltage Voc (mA), the FF value, and the maximum power value Pm (W) were calculated from the current-voltage curve. The results are shown in Table 1.

(Example 2)
A solar battery cell was manufactured in the same manner as in Example 1 except that a polyester film having a thickness of about 200 μm was used instead of the glass epoxy substrate as the insulating substrate 16 shown in FIG. And the current-voltage curve of this photovoltaic cell was produced, and short circuit current Isc (mA), open circuit voltage Voc (mA), FF value, and maximum electric power value Pm (W) were computed from this current-voltage curve. The results are shown in Table 1.

(Example 3)
Except that an aluminum film having a thickness of about 2 μm was deposited as a reflective film on the surface opposite to the surface on which the p wiring and n wiring of the polyester film of Example 2 were formed, the same as in Example 2. Solar cells were manufactured. And the current-voltage curve of this photovoltaic cell was produced, and short circuit current Isc (mA), open circuit voltage Voc (mA), FF value, and maximum electric power value Pm (W) were computed from this current-voltage curve. The results are shown in Table 1.

(Comparative Example 1)
11 except that the connection electrodes 113a and 113b shown in FIG. 15 are formed and the p-electrode 111 and the n-electrode 112 are electrically connected without using the wiring substrate 18 shown in FIG. The solar battery cell shown in FIG. Here, the connection electrodes 113a and 113b were formed by screen-printing a silver paste having a width of 180 μm, drying the paste at a temperature of about 150 ° C., and firing it for about 1 to 2 minutes in an oxidizing atmosphere of about 620 ° C. . And the current-voltage curve of this photovoltaic cell was produced, and short circuit current Isc (mA), open circuit voltage Voc (mA), FF value, and maximum electric power value Pm (W) were computed from this current-voltage curve. The results are shown in Table 1.

  As shown in Table 1, both the FF value and Pm tended to increase for the solar cells of Examples 1 to 3 as compared to the solar cell of Comparative Example 1. This is because, in the solar cells of Examples 1 to 3, the p-electrode 11 and the n-electrode 12 made of silver of the solar cell are provided by installing the wiring substrate 18 on which the p-wiring 14 and the n-wiring 15 made of copper are formed. Is electrically connected via the solder, it is considered that the contact resistance between the p wiring 14 and the p electrode 11 and between the n wiring 15 and the n electrode 12 did not increase.

  Moreover, the solar cell of Example 3 tended to increase Pm as compared with the solar cells of Examples 1-2. This is considered to be due to the effect of the reflective film formed on the polyester film.

Example 4
A solar battery cell as shown in FIG. 6 was produced as follows. First, by applying a solution containing phosphorus on the light-receiving surface of the semiconductor substrate 1 made of a p-type silicon substrate having a width of 125 mm, a length of 125 mm, and a thickness of 330 μm, and performing thermal diffusion at about 900 ° C., An n + layer 5 having a sheet resistance value of about 50Ω / □ was formed. Then, an antireflection film (not shown) made of a TiOx film having a thickness of about 60 nm was formed on the n + layer 5.

  Next, an aluminum paste was printed on the entire back surface of the semiconductor substrate 1 to a thickness of about 50 μm by screen printing, and dried at 150 ° C. for about 4 minutes to form the p + layer 6 and the p electrode 11 simultaneously. Further, a plurality of silver pastes were printed on the light receiving surface side of the semiconductor substrate 1 in the form of dots and dried at 150 ° C. for about 4 minutes to form an n-electrode 12 made of silver, thereby completing the solar cell wafer 17. Here, the n-electrode 12 was formed in a fishbone shape on the light-receiving surface of the semiconductor substrate 1 as shown in the schematic plan view of FIG. Thereafter, the n-electrode 12 was immersed in a solder bath, and the surface thereof was coated with solder.

  In addition, a wiring board 18 having a n-wiring 15 made of copper coated with solder and formed on a polyester film is placed on the light-receiving surface of the solar cell wafer 17, and hot air is blown from the solar cell wafer 17 side in the same manner as described above. The solar battery wafer 17 and the wiring board 18 were integrated with each other by cooling after melting both solders by spraying the solar cell shown in FIG.

  A current-voltage curve of this solar cell was prepared, and a short-circuit current Isc (mA), an open-circuit voltage Voc (mA), and an FF value were calculated from the current-voltage curve. The results are shown in Table 2.

(Comparative Example 2)
A solar battery cell was manufactured in the same manner as in Example 4 except that the plurality of dot-like n electrodes 12 were electrically connected by a connecting electrode made of silver without using the wiring substrate 18. And the current-voltage curve of this photovoltaic cell was produced, and short circuit current Isc (mA), open circuit voltage Voc (mA), and FF value were computed from this current-voltage curve. The results are shown in Table 2.

  As shown in Table 2, even when the wiring substrate 18 is installed on the light receiving surface of the solar cell wafer 17, a plurality of dotted n-electrodes 12 are electrically connected by an n-wiring 15 made of copper. Therefore, the contact resistance decreased, and the solar cell of Example 4 had a large FF value equivalent to that of the solar cell of Comparative Example 2.

(Example 5)
A glass epoxy substrate having a width of 150 mm and a length of 550 mm was prepared as the insulating substrate 16 shown in FIG. Then, the p wiring 14 and the n wiring 15 made of copper whose surfaces are coated with the solder 19 are formed on the glass epoxy substrate, and the connection electrode 20 made of copper having a width of 15 mm × a length of 150 mm is formed. The wiring board 18 shown in FIG.

  Further, as shown in FIG. 9, three solar cell wafers 17a, 17b, and 17c each having a width of 125 mm and a length of 125 mm were arranged. And wiring board 18 is installed on the back of these solar cell wafers 17a, 17b and 17c, and p wiring 14 and n wiring 15 made of copper of wiring board 18 and silver of solar cell wafers 17a, 17b and 17c. The p electrode 11 and the n electrode 12 are electrically connected to each other through solder. Thereby, the solar cell module shown in FIG. 8 was manufactured. It was 3.5W when the output of this solar cell module was measured.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  According to the present invention, it is possible to provide a solar cell that has a large FF (Fill Factor) value and can be manufactured at low cost, and a solar cell module using the solar cell. Therefore, the present invention is suitable for the solar cell field. Can be used.

It is typical sectional drawing of a preferable example of the photovoltaic cell of this invention. It is a flowchart of a preferable example of the manufacturing process of the photovoltaic cell of this invention. FIG. 3 is a schematic plan view of a preferred example of an arrangement of p electrodes and n electrodes formed on a light receiving surface of a semiconductor substrate used in the present invention. It is a typical top view of a desirable example of a wiring board used for the present invention. It is a typical top view of a preferable example when the wiring board used for this invention is installed on the back surface of a solar cell wafer. It is a typical side view of another example of the preferable photovoltaic cell of this invention. It is a typical top view of a preferable example of the arrangement | sequence of the n electrode formed in the light-receiving surface of the semiconductor substrate used for this invention. It is a typical top view of a preferable example of the back surface of the solar cell module of the present invention. It is a typical top view of a desirable example of the state where the solar cell wafer used for the solar cell module of the present invention is arranged. It is a typical top view of a desirable example of a wiring board used for a solar cell module of the present invention. It is typical sectional drawing of an example of the conventional back junction type photovoltaic cell. It is a typical top view of an example of the back surface of the conventional back junction type photovoltaic cell. It is a flowchart of an example of the manufacturing process of the conventional back junction type photovoltaic cell. It is the typical top view which showed the arrangement | sequence of the p electrode and n electrode which were formed in the back surface of the conventional back junction type photovoltaic cell. It is the typical top view which showed an example of the connection electrode formed in the back surface of the conventional back junction type photovoltaic cell. It is a typical top view of an example of the back of the conventional solar cell module.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Semiconductor substrate, 5,105 n + layer, 6,106 p + layer, 11,111 p electrode, 12,112 n electrode, 14 p wiring, 15 n wiring, 16 Insulating substrate, 17, 17a, 17b, 17c Solar cell wafer, 18 wiring board, 19 solder, 20, 107 connection electrode, 101 silicon substrate, 113a, 113b connecting electrode.

Claims (11)

  A solar cell wafer in which a plurality of p-electrodes and n-electrodes are formed in a dot shape on one surface of a semiconductor substrate and a p-wiring and n-wiring are formed on one surface of the insulating substrate so as to be electrically insulated from each other. A wiring substrate, wherein one surface of the wiring substrate is disposed on one surface of the solar cell wafer, the p electrode is electrically connected by the p wiring, and the n electrode is electrically connected by the n wiring. A solar battery cell that is connected.   The p electrode and the n electrode are formed of a material containing silver, the p wiring and the n wiring are formed of a material containing copper, and the connection between the p electrode and the p wiring and the n electrode The solar cell according to claim 1, wherein the connection to the n wiring is made through solder.   The p wiring and the n wiring are each formed in a comb shape including comb teeth, and the p wiring and the n wiring are disposed so that the respective comb teeth face each other, 3. The solar cell according to claim 1, wherein the comb teeth of the n wiring are alternately arranged along one surface of the insulating substrate.   The p electrode and the n electrode are respectively arranged in a line, and the arrangement line of the p electrode and the arrangement line of the n electrode are alternately arranged. The solar cell according to any one of the above.   The solar cell according to claim 1, wherein the insulating substrate is transparent.   The solar cell according to claim 5, wherein a reflective film is formed on a surface opposite to one surface of the insulating substrate.   A solar cell wafer in which a plurality of n electrodes are formed in a dot shape on a light receiving surface of a semiconductor substrate, and a wiring substrate in which n wiring is formed on one surface of an insulating substrate, on one surface of the solar cell wafer A solar battery cell, wherein one surface of the wiring substrate is installed on the substrate, the n electrodes are electrically connected by the n wiring, and the insulating substrate is transparent.   A solar cell wafer in which a plurality of p-electrodes are formed in a dot shape on a light receiving surface of a semiconductor substrate; and a wiring substrate in which p wiring is formed on one surface of an insulating substrate, on one surface of the solar cell wafer A solar battery cell, wherein one surface of the wiring substrate is disposed on the p-electrode, the p-electrode is electrically connected by the p-wiring, and the insulating substrate is transparent.   A plurality of solar cell wafers each having a plurality of p-electrodes and n-electrodes formed in a dot shape on one surface of a semiconductor substrate, and a connection for electrically connecting p-wires, n-wires, and these wires to one surface of an insulating substrate A p-electrode of one of the solar cell wafers is electrically connected to the p-wiring, and is different from the one solar cell wafer. An n-electrode of another solar cell wafer is electrically connected to the n wiring, and the solar cell module.   The p electrode and the n electrode are formed of a material containing silver, the p wiring and the n wiring are formed of a material containing copper, and the connection between the p electrode and the p wiring and the n electrode The solar cell module according to claim 9, wherein the n wiring and the n wiring are respectively connected via solder.   The p wiring and the n wiring are each formed in a comb shape including comb teeth, and the p wiring and the n wiring respectively electrically connected to the p electrode and the n electrode of the one solar cell wafer are respectively connected to each other. The comb teeth of the p wiring and the comb teeth of the n wiring are alternately arranged along one surface of the insulating substrate. The solar cell module according to 9 or 10.

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