JP2013012670A - Photoelectric conversion module and manufacturing method of the same - Google Patents

Abstract

A highly reliable photoelectric conversion module is provided by improving the adhesive strength between a wiring conductor and an electrode.
A photoelectric conversion module M includes a substrate 2 containing silicon and oxygen, an electrode provided on the substrate 2, a solder 13 provided on the electrode and containing at least one of zinc and antimony, And a wiring conductor 11 provided on the solder 13. In the photoelectric conversion module M, the electrode has a through hole 8a penetrating vertically, and is disposed so that a part of the solder 13 reaches the substrate 2 in the through hole 8a. Further, in the photoelectric conversion module M, the wiring conductor 11 is bonded to the electrode via the solder 13 so as to cover the through hole 8a, and via a part of the solder 13 disposed in the through hole 8a. Are adhered to the substrate 2.
[Selection] Figure 6

Description

  The present invention relates to a photoelectric conversion module and a manufacturing method thereof.

  In recent years, photovoltaic power generation that converts light energy into electric energy has attracted attention as energy problems and environmental problems become more serious.

  In the photoelectric conversion module used for this photovoltaic power generation, the electric power obtained from the photoelectric conversion unit is taken out through a wiring conductor or the like. In such a photoelectric conversion module, wiring conductors respectively connected to the positive electrode and the negative electrode in the photoelectric conversion module are led out to a terminal box disposed on the back surface of the photoelectric conversion module (for example, Patent Document 1). reference).

JP 2006-216608 A

  The photoelectric conversion module is often installed mainly outdoors, and is easily affected by the surrounding environment. Therefore, in the photoelectric conversion module, stress tends to concentrate on the bonding portion between the wiring conductor and the electrode in an environment where a large temperature change occurs. As a result, the wiring conductor may be peeled off from the electrode.

  One object of the present invention is to provide a highly reliable photoelectric conversion module by improving the adhesive strength between a wiring conductor and an electrode.

  A photoelectric conversion module according to an embodiment of the present invention includes a substrate containing silicon and oxygen and an electrode provided on the substrate. Furthermore, in this embodiment, a solder including at least one of zinc and antimony provided on the electrode and a wiring conductor provided on the solder are provided. In the present embodiment, the electrode has a plurality of through holes penetrating vertically, and the solder is disposed so that a part of the solder reaches the substrate. Further, in the present embodiment, the wiring conductor is bonded to the electrode via the solder so as to cover the through hole, and via a part of the solder disposed in the through hole. Bonded to the substrate.

In the method for manufacturing a photoelectric conversion module according to an embodiment of the present invention, an ultrasonic wave is applied to an electrode forming step of forming an electrode on a substrate containing silicon and oxygen, and a solder containing at least one of zinc and antimony. And a solder installation step of providing on the electrode while applying vibration. Further, the present embodiment includes a wiring conductor installation step of providing a wiring conductor on the solder, and an adhesion step of melting the solder and bonding the wiring conductor to the electrode via the solder. In the present embodiment, the electrode forming step includes a step of forming a plurality of through holes penetrating up and down at the time of installation of the electrode or after the installation of the electrode. A step of disposing a part of the solder. Further, in the present embodiment, the wiring conductor installation step includes a step of providing the wiring conductor so as to cover the through hole, and the bonding step includes the wiring via the solder disposed in the through hole. Bonding a conductor to the substrate.

  In the method for manufacturing a photoelectric conversion module according to another embodiment of the present invention, an electrode forming step of forming an electrode on a substrate containing silicon and oxygen, and a solder containing at least one of zinc and antimony are ultrasonicated. A solder installation step of providing a wiring conductor on the electrode while applying vibration by applying, and in the present embodiment, a wiring conductor installation step of providing a wiring conductor on the solder, and melting the solder to An adhering step of adhering a wiring conductor to the electrode via the solder. In the present embodiment, the solder installation step includes a step of forming a plurality of through holes that vertically penetrate the electrode by the ultrasonic wave and disposing a part of the solder in the through hole, The wiring conductor installation step includes a step of providing the wiring conductor so as to cover the through hole. Furthermore, in the present embodiment, the bonding step includes a step of bonding the wiring conductor to the substrate via the solder disposed in the through hole.

  According to the photoelectric conversion module according to one embodiment of the present invention, the wiring conductor is bonded to the electrode and the substrate via the solder. Thereby, the adhesive strength of a wiring conductor and an electrode increases, and the reliability of a photoelectric conversion module improves.

It is a perspective view which shows an example of the photoelectric conversion part of the photoelectric conversion module which concerns on one Embodiment of this invention. It is sectional drawing of the photoelectric conversion part shown in FIG. It is the perspective view seen from the light-receiving surface side of the photoelectric conversion module which concerns on one Embodiment of this invention. It is the perspective view seen from the back surface side of the photoelectric conversion module shown in FIG. It is sectional drawing of the AA part of FIG. It is a partial expanded sectional view along the Y direction of the B section of FIG. (A)-(e) is sectional drawing explaining the manufacturing method of the photoelectric conversion module which concerns on one Embodiment of this invention. It is a plane perspective view of the site | part in which the wiring conductor and output conductor of the photoelectric conversion module which concern on one Embodiment of this invention are located. It is sectional drawing which shows an example of the solder installation process in the manufacturing method of the photoelectric conversion module which concerns on one Embodiment of this invention. (A)-(d) is sectional drawing explaining the manufacturing method of the photoelectric conversion module which concerns on other embodiment of this invention. It is sectional drawing which shows an example of the solder installation process in the manufacturing method of the photoelectric conversion module which concerns on other embodiment of this invention. It is a plane perspective view of the site | part in which the wiring conductor and output conductor of the photoelectric conversion module which concern on one Embodiment of this invention are located.

  An example of an embodiment of the photoelectric conversion module of the present invention will be described with reference to the drawings.

  First, a photoelectric conversion unit that is a part of the photoelectric conversion module will be described. Each figure may have a right-handed XYZ coordinate with the X-axis being the alignment direction of photoelectric conversion cells described later.

<Photoelectric conversion unit>
The photoelectric conversion unit 1 is provided on one main surface of the substrate 2. And this photoelectric conversion part 1 is
It has the lower electrode 3, the photoelectric converting layer provided with the light absorption layer 4 and the buffer layer 5, and the upper electrode provided with the translucent conductive layer 6 and the current collection electrode 7. In the photoelectric conversion unit 1, photoelectric conversion is performed by the light absorption layer 4 and the buffer layer 5 sandwiched between the lower electrode 3 and the upper electrode.

  As shown in FIG. 1, the photoelectric conversion unit 1 is configured such that a plurality of photoelectric conversion cells 1 a and 1 b are electrically connected. Specifically, as shown in FIG. 1, an upper electrode (collecting electrode 7) of one photoelectric conversion cell 1a and a lower electrode 3 of the other photoelectric conversion cell 1b adjacent to one photoelectric conversion cell 1a are provided. Electrically connected. Thereby, the adjacent photoelectric conversion cells 1 a and 1 b are connected in series along the X direction in FIG. 1 and are integrated on the substrate 2.

  In addition, the photoelectric conversion unit 1 is provided with output electrodes 8 (output electrodes 8A and 8B) for leading the electrical output obtained by the photoelectric conversion unit 1 to the outside.

  Next, each member of the photoelectric conversion unit 1 will be described.

  A plurality of lower electrodes 3 are arranged on one main surface of the substrate 2 at intervals in one direction (X direction in FIG. 1). In the present embodiment, as shown in FIG. 2, three lower electrodes 3 are provided that are separated from each other by a separation groove P <b> 1 corresponding to the interval. The number of lower electrodes 3 is not limited to that shown in FIG. Such a lower electrode 3 may be a thin film containing a metal such as molybdenum (Mo), aluminum (Al), titanium (Ti), tantalum (Ta) or gold (Au) or an alloy thereof. Moreover, the structure formed by laminating | stacking these metals may be sufficient. The lower electrode 3 may be formed to a thickness of about 0.2 to 1 μm on the substrate 2 by using a sputtering method or a vapor deposition method, for example.

The light absorption layer 4 is disposed on the lower electrode 3. The light absorption layer 4 includes, for example, a compound semiconductor. An example of such a compound semiconductor is a chalcogen compound semiconductor. A chalcogen compound semiconductor contains sulfur (S), selenium (Se) or tellurium (Te) which are chalcogen elements. An example of the chalcogen compound semiconductor is an I-III-VI compound semiconductor. An I-III-VI compound semiconductor is a compound of a group IB element (also referred to as a group 11 element), a group III-B element (also referred to as a group 13 element) and a group VI-B element (also referred to as a group 16 element). It is a semiconductor. Such an I-III-VI compound semiconductor has a chalcopyrite structure and is also called a chalcopyrite compound semiconductor (also referred to as a CIS compound semiconductor). Examples of the I-III-VI compound semiconductor include copper indium diselenide (CuInSe ₂ ), copper indium diselenide / gallium (Cu (In, Ga) Se ₂ ), diselen selenide / copper indium / gallium (gallium ( Cu (In, Ga) (Se, S) ₂ ), copper indium gallium disulfide (Cu (In, Ga) S ₂ ), or a thin film of selenium disulfide / copper indium / gallium as a surface layer There are multi-element compound semiconductor thin films such as copper indium selenide and gallium. The compound semiconductor included in the light absorption layer 4 is not only the above-described I-III-VI compound semiconductor, but also, for example, CZTS including copper (Cu), zinc (Zn), tin (Sn), and sulfur (S). It may be of the type. An example of such a CZTS compound semiconductor is Cu ₂ ZnSnS ₄ . Since the CZTS compound semiconductor does not use rare metal unlike the I-III-VI compound semiconductor, it is easy to secure the material. The light absorption layer 4 has, for example, a p-type conductivity and has a thickness of about 1 to 3 μm.

  The light absorption layer 4 is formed by a vacuum process such as sputtering or vapor deposition. The light absorption layer 4 is also formed by a process called a coating method or a printing method. In the coating method or the printing method, for example, a complex solution of elements mainly contained in the light absorption layer 4 is applied on the lower electrode layer 3, and then drying and heat treatment are performed.

  The buffer layer 5 is provided on the main surface on the + Z side of the light absorption layer 4 and has a second conductivity type (here, n-type conductivity type) different from the first conductivity type of the light absorption layer 4. Mainly includes semiconductors. Note that semiconductors having different conductivity types are semiconductors having different conductive carriers. Moreover, the conductivity type of the light absorption layer 4 may be n-type, and the conductivity type of the buffer layer 5 may be p-type. Here, a heterojunction region is formed between the buffer layer 5 and the light absorption layer 4. For this reason, in each photoelectric conversion cell, photoelectric conversion can occur in the light absorption layer 4 and the buffer layer 5 that form the heterojunction region.

The buffer layer 5 mainly contains a compound semiconductor. Examples of the compound semiconductor included in the buffer layer 5 include cadmium sulfide (CdS), indium sulfide (In ₂ S ₃ ), zinc sulfide (ZnS), zinc oxide (ZnO), indium selenide (In ₂ Se ₃ ), In (OH, S), (Zn, In) (Se, OH), (Zn, Mg) O, and the like. Further, if the buffer layer 5 has a resistivity of 1 Ω · cm or more, generation of leak current can be reduced. The buffer layer 5 can be formed by, for example, a chemical bath deposition (CBD) method or the like.

  The buffer layer 5 has a thickness in the normal direction (+ Z direction) of one main surface of the light absorption layer 4. This thickness is set to, for example, 10 to 200 nm. When the thickness of the buffer layer 5 is 100 to 200 nm, damage is unlikely to occur in the buffer layer 5 when the translucent conductive layer 6 is formed on the buffer layer 5 by a sputtering method or the like.

  The translucent conductive layer 6 is provided on the main surface on the + Z side of the buffer layer 5 and is, for example, a transparent conductive layer (also referred to as a transparent conductive layer) having an n-type conductivity type. The translucent conductive layer 6 functions as an electrode for extracting charges generated in the light absorption layer 4 (also referred to as an extraction electrode). The translucent conductive layer 6 mainly includes a material having a lower resistivity than the buffer layer 5. The translucent conductive layer 6 may include what is called a window layer, and may include a window layer and a transparent conductive layer.

The translucent conductive layer 6 mainly includes a material having a wide forbidden band, transparent, and low resistance. Examples of such a material include zinc oxide (ZnO), a compound of zinc oxide, and metal oxide semiconductors such as indium oxide (ITO) containing tin and tin oxide (SnO ₂ ). The zinc oxide compound contains any one element of aluminum, boron, gallium, indium, and fluorine.

  The translucent conductive layer 6 can be formed by sputtering, vapor deposition, chemical vapor deposition (CVD), or the like. The thickness of the translucent conductive layer 6 is, for example, 0.05 to 3.0 μm. Here, if the translucent conductive layer 6 has a resistivity of less than 1 Ω · cm and a sheet resistance of 50 Ω / □ or less, the charge is transferred from the light absorption layer 4 via the translucent conductive layer 6. Can be taken out well.

  The buffer layer 5 and the translucent conductive layer 6 may have a property (also referred to as light transmissivity) that allows light to easily pass through the wavelength band of light that can be absorbed by the light absorption layer 4. Thereby, the fall of the light absorption efficiency in the light absorption layer 4 can be reduced. Moreover, if the thickness of the translucent conductive layer 6 is 0.05 to 0.5 μm, the light transmissivity in the translucent conductive layer 6 is enhanced, and at the same time, the current generated by the photoelectric conversion is satisfactorily transmitted. obtain. Further, if the absolute refractive index of the translucent conductive layer 6 and the absolute refractive index of the buffer layer 5 are substantially the same, the incidence caused by the reflection of light at the interface between the translucent conductive layer 6 and the buffer layer 5. Light loss can be reduced.

The current collecting electrode 7 has a linear portion 7 a provided on the + Z side main surface (also referred to as one main surface) of the translucent conductive layer 6 and a connection portion 7 b. Then, for example, the charges collected by the translucent conductive layer 6 of the photoelectric conversion cell 1a can be further collected by the linear portion 7a and transmitted to the adjacent photoelectric conversion cell 1b through the connection portion 7b.

  By providing the linear portion 7a, the conductivity of the translucent conductive layer 6 is supplemented, so that the translucent conductive layer 6 can be thinned. Thereby, securing of charge extraction efficiency and improvement of light transmittance in the translucent conductive layer 6 can both be achieved. In addition, if the linear part 7a mainly contains the metal which was excellent in electroconductivity, such as silver, the conversion efficiency in the photoelectric conversion part 1 can improve. In addition, as a metal contained in the linear part 7a, copper, aluminum, nickel, etc. are mentioned, for example.

  Moreover, if the width | variety of the linear part 7a is 50-400 micrometers, the fall of the incident amount of the light to the light absorption layer 4 is ensured, ensuring favorable electroconductivity between the adjacent photoelectric conversion cell 1a and the photoelectric conversion cell 1b. Can be reduced. When a plurality of linear portions 7a are provided in one photoelectric conversion cell, the interval between the plurality of linear portions 7a may be about 2.5 mm, for example.

  In addition, if the surface of the linear part 7a has the property to reflect the light of the wavelength region which the light absorption layer 4 can absorb, when the photoelectric conversion part 1 is modularized, the linear part The light reflected on the surface of 7a can be reflected again in the module and incident on the light absorption layer 4. Thereby, the conversion efficiency in the photoelectric conversion part 1 can improve. Such a linear portion 7a may be formed using, for example, a paste in which metal particles such as silver having a high light reflectance are added to a translucent resin. It can also be realized by depositing a metal having a high light reflectance such as aluminum on the surface of the linear portion 7a.

  The connecting portion 7 b is disposed in the separation groove P <b> 2 that separates the light absorption layer 4 and the buffer layer 5. The connection portion 7b is electrically connected to the linear portion 7a. For example, the connection portion 7b located in the photoelectric conversion cell 1a has a hanging portion that connects to the lower electrode 3 extending from the adjacent photoelectric conversion cell 1b through the separation groove P2. Thereby, the connection part 7b electrically connects the upper electrode (the translucent conductive layer 6 and the linear part 7a) of the photoelectric conversion cell 1a and the lower electrode 3 of the photoelectric conversion cell 1b in FIG. 1A. it can. In FIG. 1, the linear portion 7a of the photoelectric conversion cell 1a electrically connected to the translucent conductive layer 6 and the lower electrode 3 of the photoelectric conversion cell 1b are directly connected. Not limited. For example, the connecting portion 7b electrically connects the upper electrode of the photoelectric conversion cell 1a and the lower electrode 3 of the photoelectric conversion cell 1b via at least one of the buffer layer 5 and the translucent conductive layer 6 disposed in the separation groove P2. It may be a form of connection to.

  The connecting portion 7b may be made of the same material and method as the linear portion 7a. Therefore, the connecting portion 7b may be performed simultaneously with the formation of the linear portion 7a. Moreover, the connection part 7b may be a part of the linear part 7a.

  The output electrodes 8A and 8B output the current converted from light in each photoelectric conversion cell to the outside. One of the output electrode 8A and the output electrode 8B is a positive electrode, and the other is a negative electrode. In the present embodiment, an output electrode 8A is provided on one end side of the photoelectric conversion unit 1, and an output electrode 8B is provided on the other end side. That is, it can be said that the output electrode 8A and the output electrode 8B are electrically connected to the photoelectric conversion unit 1. Specifically, in the present embodiment, the output electrode 8A corresponds to a portion where a part of the lower electrode 3 located on one end side (−X direction) of the photoelectric conversion cell 1a is extended. On the other hand, the output electrode 8B corresponds to a portion where a part of the lower electrode 3 located on the other end side (+ X direction) of the photoelectric conversion cell 1b is extended. In the present embodiment, the output electrode 8A and the output electrode 8B are formed by extending a part of the lower electrode 3, but the present invention is not limited to this. For example, the output electrode 8A and the output electrode 8B may be formed by extending a part of the upper electrode of the photoelectric conversion cell. When three or more photoelectric conversion cells are arranged, an output electrode 8A is provided in the photoelectric conversion cell located at one end of the photoelectric conversion unit 1 and the photoelectric conversion cell located at the other end of the photoelectric conversion unit 1 Is provided with an output electrode 8B.

  Next, an example of a method for manufacturing the photoelectric conversion unit 1 will be described.

  First, a metal such as molybdenum is formed on the substantially entire surface excluding about 3 to 20 mm inward from the outer peripheral portion of the substrate 2 to form the lower electrode 3. Next, a desired position of the lower electrode 3 is irradiated with a YAG (yttrium, aluminum, garnet) laser or the like to form a dividing groove P1, and the lower electrode 3 is patterned. Next, the light absorption layer 4 is formed on the patterned lower electrode 3 by using a sputtering method, a vapor deposition method, a printing method, or the like. Next, the buffer layer 5 is formed on the light absorption layer 4 by a solution growth method (CBD method) or the like.

  Next, the translucent conductive layer 6 is formed on the buffer layer 5 by sputtering or metal organic chemical vapor deposition (MOCVD). Next, the dividing groove P2 is formed by mechanical scribing or the like, and the light absorption layer 4, the buffer layer 5, and the translucent conductive layer 6 are patterned. Next, after applying a metal paste on the translucent conductive layer 6 by screen printing or the like, the current collector electrode 7 is formed by baking. Next, the photoelectric conversion unit 1 is formed by forming a plurality of photoelectric conversion cells arranged in the X direction by forming the dividing grooves P3 along the Y direction by mechanical scribing or the like and performing patterning.

  Next, for the photoelectric conversion cells (photoelectric conversion cell 1a and photoelectric conversion cell 1b in this embodiment) located at both ends in the X direction, for example, using a blade, a wheel brush, or the like, the light absorption layer 4, the buffer layer 5, the transparent layer, and the like. The photoconductive layer 6, the collecting electrode 7 and the like are scraped off with a width of about 2 to 7 mm, and a part of the lower electrode 3 is extended. Thereby, the output electrode 8A is formed at one end of the photoelectric conversion cell 1a, and the output electrode 8B is formed at the other end of the photoelectric conversion cell 1b.

<Photoelectric conversion module>
As shown in FIGS. 3 and 4, the photoelectric conversion module M according to one embodiment of the present invention includes a photoelectric conversion unit 1, a substrate 2, a covering member 9, a protective substrate 10, a wiring conductor 11, and terminals. And a box 12.

  The substrate 2 has a function of supporting the photoelectric conversion unit 1. The substrate 2 is made of a material containing silicon and oxygen. Specifically, examples of the material of the substrate 2 include blue plate glass (soda lime glass) or borosilicate glass having a thickness of about 1 to 3 mm. Moreover, the shape of the board | substrate 2 should just be flat form, such as rectangular shape and circular shape, for example.

  As shown in FIG. 5, the covering member 9 is filled between one main surface of the substrate 2 and the protective substrate 10 facing each other. The covering member 9 has a function of adhering the substrate 2 and the protective substrate 10 while protecting the photoelectric conversion unit 1. The covering member 9 is disposed so as to cover the photoelectric conversion unit 1. Examples of such a covering member 9 include a resin mainly composed of copolymerized ethylene vinyl acetate (EVA). Note that EVA may contain a crosslinking agent such as triallyl isocyanurate in order to promote crosslinking of the resin.

  The protective substrate 10 is provided so as to be in contact with the covering member 9 and has a function of protecting the photoelectric conversion unit 1 and the like from the outside. The size and shape of the protective substrate 10 are substantially the same as those of the substrate 2. As the protective substrate 10, for example, white plate glass that has been tempered with air cooling can be used in terms of light transmittance and required strength.

The wiring conductor 11 is electrically connected to the output electrode 8, and has a function of guiding the output of the photoelectric conversion unit 1 to the outside through the output electrode 8. In the present embodiment, the wiring conductor 11A is electrically connected to the output electrode 8A. On the other hand, the wiring conductor 11B is electrically connected to the output electrode 8B. As shown in FIG. 3, the wiring conductor 11 </ b> A and the wiring conductor 11 </ b> B are drawn to the back side of the substrate 2 through the opening 2 a provided in the substrate 2 and extend into the terminal box 12. The opening 2a is a through-hole penetrating the substrate 2 formed from one main surface of the substrate 2 toward the other main surface. The opening 2a may be provided in advance before the photoelectric conversion unit 1 is formed on the substrate 2, or may be provided after the photoelectric conversion unit 1 is formed. When the substrate 2 is blue glass, the opening 2a can be formed by a machining method using a drill or the like, a laser processing method using a YAG (yttrium, aluminum, garnet) laser, or the like.

  The wiring conductor 11 is made of, for example, a metal foil such as copper, silver, aluminum, an alloy containing these, or a laminate having a thickness of about 0.3 to 2 mm. The width of the wiring conductor 11 may be about 50% to 90% of the width of the output electrodes 8A and 8B, for example.

  As shown in FIG. 6, the wiring conductor 11 is connected to the output electrode 8 via the solder 13. The solder 13 contains at least one of zinc (Zn) and antimony (Sb). Examples of such solder 13 include those containing about 80 to 90% by weight of tin (Sn) and about 10 to 20% by weight of zinc or antimony. Other compositions of the solder 13 include, for example, tin. It may contain about 80 to 90% by weight, about 1 to 10% by weight of zinc, and 1 to 10% by weight of antimony. The solder 13 may be applied in advance to the surface of the output electrode 8 to which the wiring conductor 11 is bonded.

  In addition, as shown in FIG. 6, a part of the solder 13 enters the through hole 8 a provided in the output electrode 8. The through hole 8a is provided so as to penetrate the output electrode 8 in the vertical direction (Z direction in FIG. 6). Therefore, the solder 13 disposed in the through hole 8 a is positioned so as to reach the surface of the substrate 2. The wiring conductor 11 is bonded to the output electrode 8 via the solder 13 so as to cover the through hole 8a. Therefore, the wiring conductor 11 is also bonded to the substrate 2 through the solder 13 disposed in the through hole 8a. Therefore, the wiring conductor 11 is bonded to both the substrate 2 and the output conductor 8.

  As described above, the substrate 2 contains silicon and oxygen, and the solder 13 contains at least one of zinc and antimony. Therefore, a bond of silicon, oxygen and zinc (Si—O—Zn) or a bond of silicon, oxygen and antimony (Si—O—Sb) is provided between the solder 13 disposed in the through hole 8a and the substrate 2. Is formed. Thereby, since the wiring conductor 11 can be adhered to the substrate 2, the bonding strength between the wiring conductor 11 and the output electrode 8 can be increased.

  The shape of the through hole 8a is not particularly limited, and may be a circle, an ellipse, a quadrangle, or the like when the output electrode 8 is viewed in plan. Further, the through hole 8a may have an elongated shape when the output electrode 8 is viewed in plan. Moreover, the width | variety of the through-hole 8a should just be 50-200 micrometers. In addition, the area of the through hole 8 a obtained by viewing the output electrode 8 in plan view may be 0.1 to 5% of the adhesion area between the wiring conductor 11 and the output electrode 8. Thereby, it is possible to increase the adhesive strength while ensuring the conduction between the wiring conductor 11 and the output electrode 8.

  The wiring conductor 11 may have a coating layer containing at least one of zinc and antimony on the surface in contact with the solder 13. Thereby, formation of a bond of silicon, oxygen and zinc or a bond of silicon, oxygen and antimony between the substrate 2 and the solder 13 is promoted. The covering layer may be the same component as the solder 13. As a result, when the solder 13 is heated and the wiring conductor 11 is bonded (soldered) to the output electrode 8, the solder 13 and the coating layer are easily mixed, and a decrease in the adhesive strength is reduced. Such a coating layer is coated on the surface of the wiring conductor 11 by a method such as plating or dipping, for example. Further, the coating layer may be coated on a surface other than the surface to be bonded to the solder 13.

  Next, an embodiment of a method for manufacturing a photoelectric conversion module will be described.

(Embodiment 1)
First, as illustrated in FIG. 7A, the photoelectric conversion unit 1 is formed on the substrate 2. In addition, what is necessary is just to form the photoelectric conversion part 1 by the method mentioned above. Next, the surface of the lower electrode 2 located on the outer peripheral side of the photoelectric conversion unit 1 is exposed by mechanical scribing or the like to form the output electrode 8 (output electrode 8A and output electrode 8B).

  Next, as shown in FIG. 7B, a through hole 8a is provided in the vicinity of the center of the portion where the wiring conductor 11 of the output electrode 8 is disposed. Further, the through hole 8a may be formed by removing a part of the output electrode 8 using a YAG laser with a Q switch or the like. In the above electrode forming step, the through hole 8a is formed after the output electrode 8 is installed. However, the through hole 8a may be provided when the output electrode 8 is installed. In such an electrode formation step, for example, after the photoelectric conversion unit 1 is formed on the substrate 2, the output electrode 8 (output electrode 8 </ b> A and output electrode 8 </ b> B) electrically connected to the lower electrode 3 is sputtered on the substrate 2. When forming using a method or the like, a mask is formed with a photoresist using a photolithography method or the like at a position where the through-hole 8a is provided, and then a metal layer is formed using a sputtering method and then the mask is removed. Thus, the output electrode 8 may be obtained.

  Further, when the through hole 8a has an elongated shape in plan view, the through hole 8a may be formed so as to extend from one end portion in the longitudinal direction of the output electrode 8 to the other end portion. In the case of such a shape, a plurality of through holes 8a may be provided. Thereby, the adhesive strength between the wiring conductor 11 and the output electrode 8 is increased. Further, as shown in FIG. 8, a plurality of through holes 8 a may be provided at intervals along the longitudinal direction (Y direction) of the output electrode 8. At this time, the length of the through hole 8a is about 10 to 50 mm. Moreover, the length from the edge part of the through-hole 8a to the edge part of the adjacent through-hole 8a is about 5-50 mm. When a plurality of such through holes 8a are provided, the wiring conductor 11 is partially heated with a soldering iron or the like in accordance with the position of the through hole 8a. As a result, the amount of heat received by the wiring conductor 11 and the substrate 2 during bonding can be reduced, and the stress generated from the difference in thermal expansion coefficient generated after cooling can also be reduced. Therefore, a decrease in the adhesive strength between the wiring conductor 11 and the substrate 2 is reduced.

  In addition, the wiring conductor 11 has a long and narrow shape in plan view (a long and narrow shape in the Y direction in FIG. 3), and as shown in FIG. By adopting a long and narrow shape, the durability against thermal stress that is likely to occur after installation outdoors can be improved.

  Next, as shown in FIG. 7C, the solder 13 is provided on the output electrode 8. In this solder installation step, the solder 13 is provided on the output electrode 8 while applying vibration by applying ultrasonic waves. In such a solder installation step, as shown in FIG. 9, the solder iron 14 to which an ultrasonic wave can be applied is moved along the longitudinal direction of the output electrode 8 while supplying the solder wire 15. Solder 13 is installed on the board. Thereby, a part of the solder 13 is arranged in the through hole 8a. At this time, the solder 13 is disposed so as to reach the substrate 2. As various conditions of this solder installation process, for example, when the output electrode 8 is formed of molybdenum having a thickness of about 0.2 to 1 μm, the output is about 0.5 to 3 W and the tip temperature is 300 to 400. What is necessary is just to scan the soldering iron 14 set to about ° C. at a speed of about 20 to 100 mm / second. Moreover, the frequency of the applied ultrasonic wave should just be 40-80 kHz. By performing soldering while applying ultrasonic waves in this manner, the solder 13 containing at least one of zinc and antimony can be easily bonded to the substrate 2.

Next, as illustrated in FIG. 7D, the wiring conductor 11 is provided on the solder 13. In this wiring conductor installation step, the wiring conductor 11 is provided on the solder 13 so as to cover the through hole 8a.

  Next, as shown in FIG. 7 (e), the solder iron 16 is scanned on the wiring conductor 11 to melt the solder 13 by heat, and the wiring conductor 11 is bonded to the output electrode 8 through the solder 13. To do. This bonding step includes a step of bonding the wiring conductor 11 and the substrate 2 via the solder 13 disposed in the through hole 8a. In this bonding step, when the solder 13 is melted, ultrasonic waves may be applied in addition to heat to apply vibration to the solder 13. Thereby, the solder 13 is easily bonded to the output electrode 8 and the wiring conductor 11. The wiring conductor 11 is bonded to the output electrode 8 through the above-described electrode formation process, solder installation process, wiring conductor installation process, and bonding process.

  Next, a covering member 9 such as EVA is disposed on the photoelectric conversion unit 1, and a protective substrate 10 is placed thereon. Next, this laminated member is set in a laminating apparatus, and is integrated by being pressurized and integrated at a temperature of about 100 to 200 ° C. under a reduced pressure of about 50 to 150 Pa for about 15 to 60 minutes, thereby photoelectric conversion. A module is formed.

(Embodiment 2)
Next, a method for manufacturing the photoelectric conversion module according to Embodiment 2 will be described. This embodiment is different from the first embodiment in the electrode formation process and the solder installation process.

  First, as shown in FIG. 10A, the photoelectric conversion unit 1 is formed on the substrate 2. Next, the output electrode 8 (output electrode 8A and output electrode 8B) is formed by exposing the surface of the lower electrode 2 located on the outer peripheral side of the photoelectric conversion unit 1 by mechanical scribing or the like (electrode formation step).

Next, as shown in FIG. 10B, the solder 13 is provided on the output electrode 8 while applying vibration by applying ultrasonic waves. In such a solder installation process, the through-hole 8a can be formed in the output electrode 8 by applying an ultrasonic wave. That is, in this solder installation step, a part of the solder 13 is disposed in the through hole 8a while forming the through hole 8a while applying the solder 13 on the output electrode 8. For example, as shown in FIG. 11, solder 13 is placed on the output electrode 8 by moving the solder iron 14 to which ultrasonic waves can be applied along the longitudinal direction of the output electrode 8 while supplying the solder wire 15. . At this time, physical impact is applied to the output electrode 8 by application of ultrasonic waves, and fine through holes 8 a are formed in the output electrode 8. The through holes 8a have a diameter of about 10 to 300 μm and are formed with about 1 to 10 per 1 mm ² .

  For example, when the output electrode 8 is formed of molybdenum having a thickness of about 0.2 to 1 μm, the output is about 6 to 10 W and the tip temperature is about 300 to 400 ° C. What is necessary is just to scan the soldering iron 14 set to about 20-100 mm / sec. Moreover, the frequency of the applied ultrasonic wave should just be 40-80 kHz. By performing soldering while applying ultrasonic waves in this manner, the solder 13 containing at least one of zinc and antimony can be easily bonded to the substrate 2.

  Next, as shown in FIG. 10C, the wiring conductor 11 is provided on the solder 13. In this wiring conductor installation step, the wiring conductor 11 is provided on the solder 13 so as to cover the through hole 8a.

  Next, as shown in FIG. 10 (d), the solder rod 16 is scanned over the wiring conductor 11 to melt the solder 13 by heat, and the wiring conductor 11 is bonded to the output electrode 8 via the solder 13. To do. This bonding step includes a step of bonding the wiring conductor 11 and the substrate 2 via the solder 13 disposed in the through hole 8a. In this bonding step, when the solder 13 is melted, ultrasonic waves may be applied in addition to heat to apply vibration to the solder 13. Thereby, the solder 13 is easily bonded to the output electrode 8 and the wiring conductor 11. The wiring conductor 11 is bonded to the output electrode 8 through the above-described electrode formation process, solder installation process, wiring conductor installation process, and bonding process.

  In addition, this invention is not limited to the said embodiment, Many corrections and changes can be added within the scope of the present invention. For example, the photoelectric conversion module is not limited to the above-described CIS-based chalcopyrite-based photoelectric conversion module, and can also be applied to a photoelectric conversion module using a thin-film photoelectric conversion cell using amorphous silicon or microcrystalline silicon. is there.

  Further, in the first and second embodiments described above, as shown in FIG. 12, the wiring conductor 11 is bonded to the output electrode 8 via the solder 13 at intervals along the longitudinal direction of the wiring conductor 11. You may do it. This is because the solder 13 is melted as shown in FIG. 12 by placing the soldering iron 16 on the wiring conductor 11 at intervals along the longitudinal direction of the output electrode 8 in the bonding step of each embodiment. The plurality of bonding portions 17 may be bonded. As a result, the wiring conductor 11 is partially heated by the soldering iron 14, so that the amount of heat received by the wiring conductor 11 during bonding can be reduced. In addition, since the stress generated from the difference in thermal expansion coefficient among the wiring conductor 11, the output electrode 8, the substrate 2, and the solder 13 can be reduced after the solder 13 is cooled, the bonding strength of the wiring conductor 11 is reduced. Can be reduced. In the present embodiment, the solder 13 may be arranged so as to be independent from each other along the longitudinal direction of the output electrode 8 (longitudinal direction of the wiring conductor 11). The solder 13 may be partially melted and bonded to the solder. With this method, the solder 13 can be melted and bonded at a desired position, thereby simplifying the bonding process. In addition, as shown in FIG. 12, the solder 13 may be disposed at a portion where the through hole 8a is formed, or the solder 13 may be disposed at a portion where the through hole 8a is not formed.

M: photoelectric conversion module 1: photoelectric conversion unit 2: substrate 2a: opening 3: lower electrode 4: light absorption layer 5: buffer layer 6: translucent conductive layer 7: collecting electrode 7a: linear portion 7b : Connection part 8, 8A, 8B: Output electrode (electrode)
8a: Through-hole 9: Cover member 10: Protective substrate 11, 11A, 11B: Wiring conductor 12: Terminal box 13: Solder 14, 16: Solder rod 15: Solder wire 17: Adhesive portion

Claims (9)

A substrate comprising silicon and oxygen;
An electrode provided on the substrate;
Solder containing at least one of zinc and antimony provided on the electrode;
A wiring conductor provided on the solder,
The electrode has a through-hole penetrating vertically, and is disposed so that a part of the solder reaches the substrate in the through-hole,
The wiring conductor is bonded to the electrode via the solder so as to cover the through hole, and is bonded to the substrate via a part of the solder disposed in the through hole. , Photoelectric conversion module. The wiring conductor has an elongated shape in plan view,
The photoelectric conversion module according to claim 1, wherein the through hole has an elongated shape along a longitudinal direction of the wiring conductor in a plan view. The wiring conductor has a coating layer on the surface in contact with the solder,
The photoelectric conversion module according to claim 1, wherein the coating layer contains at least one of zinc and antimony.   4. The photoelectric conversion module according to claim 2, wherein the wiring conductor is bonded to the electrode via the solder at an interval along the longitudinal direction. 5. Forming an electrode on a substrate containing silicon and oxygen; and
A solder installation step of providing a solder containing at least one of zinc and antimony on the electrode while applying vibration by applying an ultrasonic wave;
A wiring conductor installation step of providing a wiring conductor on the solder;
An adhesion step of melting the solder and adhering the wiring conductor to the electrode via the solder,
The electrode forming step includes a step of forming a plurality of through holes penetrating vertically when the electrode is installed or after the electrode is installed,
The solder installation step includes a step of disposing a part of the solder in the through hole,
The wiring conductor installation step includes a step of providing the wiring conductor so as to cover the through hole,
The method of manufacturing a photoelectric conversion module includes a step of bonding the wiring conductor to the substrate through the solder disposed in the through hole in the bonding step. Forming an electrode on a substrate containing silicon and oxygen; and
A solder installation step of providing a solder containing at least one of zinc and antimony on the electrode while applying vibration by applying an ultrasonic wave;
A wiring conductor installation step of providing a wiring conductor on the solder;
An adhesion step of melting the solder and adhering the wiring conductor to the electrode via the solder,
The solder installation step includes a step of forming a plurality of through holes vertically penetrating the electrode by the ultrasonic wave and disposing a part of the solder in the through hole,
The wiring conductor installation step includes a step of providing the wiring conductor so as to cover the through hole,
The method of manufacturing a photoelectric conversion module includes a step of bonding the wiring conductor to the substrate through the solder disposed in the through hole in the bonding step.   The photoelectric conversion module according to claim 6, wherein the solder installation step is performed by bringing a solder iron into contact with the electrode.   The method for manufacturing a photoelectric conversion module according to claim 5 or 6, wherein, in the bonding step, when the solder is melted, heat is applied while applying vibration by applying ultrasonic waves.   The method for manufacturing a photoelectric conversion module according to claim 5, wherein, in the electrode forming step, the through hole is formed in the electrode by irradiating a laser beam after the electrode is formed.

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