JPWO2013039213A1 - Conductive member connection structure, metal foil pattern laminate, and solar cell module - Google Patents

Abstract

The connection structure of the conductive member includes an aluminum wiring and a conductive connection unit that connects the aluminum wiring to the conductive unit to conduct electricity, and the conductive connection unit includes at least a plurality of fine silver contacts with the aluminum wiring. A first silver paste containing particles, and conductive metal particles that are in contact with the plurality of silver particles and extend longer than the silver particles in a direction from the aluminum wiring toward the conductive unit.

Description

  The present invention relates to a conductive member connection structure in which an aluminum wiring and a conductive connection member are connected, a metal foil pattern laminate including the connection structure, and solar cells connected to the metal foil pattern laminate. The present invention relates to a sealed solar cell module.

In recent years, solar power generation, which is a power generation system using natural energy, has been rapidly spread. A solar cell module 200 that performs solar power generation is shown in FIG. The solar cell module 200 includes a translucent substrate 120, a solar cell module base material (back sheet) 110, and a translucent substrate 120 and a solar cell module base material 110 disposed on the light incident surface. It has a large number of sealed solar cells 130. Further, the solar battery cell 130 is sealed by being sandwiched between sealing films 140a and 140b such as an ethylene / vinyl acetate copolymer (EVA) film.
In the solar cell module 200, a plurality of solar cells 130 are electrically connected in series with a wiring material 150. The solar battery cell 130 is provided with a negative electrode 131 on the surface which is a sunlight receiving surface 130a and a positive electrode 132 on the back surface. Therefore, when connected by the wiring material 150, the wiring material 150 overlaps with the light receiving surface 130a, and there is a defect that the area efficiency of photoelectric conversion is reduced.

Moreover, in the arrangement | positioning of the electrodes 131 and 132 mentioned above, since it becomes the structure which connects the wiring material 150 to the back surface of the photovoltaic cell 130, there exists a possibility that the wiring material 150 may be disconnected by the difference in the thermal expansion coefficient of each member. was there.
Therefore, Patent Documents 1 and 2 propose a back contact type solar cell in which both a positive electrode and a negative electrode are installed on the back surface of the cell. In the solar cell of this system, both electrodes can be connected in series on the back surface of the cell, and reduction in the light receiving rate and the photoelectric conversion area efficiency can be prevented without reducing the light receiving area on the cell surface. Moreover, since it is not necessary to make it the structure which connects a wiring material from the surface to a back surface, the disconnection of the wiring material by the difference in the thermal expansion coefficient of each member can also be prevented.

As such a solar cell module, a laminated body in which a metal foil having a wiring pattern for connecting to a solar cell is attached to the surface of an insulating base material via an adhesive layer is used as a solar cell backsheet. In some cases, a part formed by laminating the material is distributed in the market.
For example, in the laminate 100 as a solar cell module substrate as shown in FIG. 8, a sheet member in which a metal foil 103 having a wiring pattern 103 a formed thereon is bonded to the substrate 101 via an adhesive layer 102. Is laminated on the surface of the back sheet 110.

In this laminated body 100, when forming the wiring pattern 103a, a photoresist is applied to the sheet-like metal foil 103, and a mask having the same pattern as the wiring pattern 103a is placed and exposed. Thereafter, unnecessary resist is removed and etching is performed with a resist pattern on the metal foil 103, whereby a predetermined wiring pattern 103 a is formed on the metal foil 103.
The wiring pattern 103a is energized by joining electrodes provided on the back surface of the solar battery cell via a conductive connecting member.

  In the laminated body described in Patent Documents 1 and 2 described above, copper was mainly used as a metal for forming a wiring pattern to be laminated on the laminated body of metal foil. However, since copper is expensive, it is relatively inexpensive. It has been proposed to use aluminum wiring.

JP 2005-11869 A JP 2009-111122 A JP 2007-76288 A

However, when the electrode on the back surface of the solar battery cell is joined to the wiring pattern of the aluminum wiring through the conductive connecting member, the oxide film of alumina Al ₂ O ₃ is formed on the surface of the aluminum wiring, In the case where the conductive connecting member is a solder material, there is a drawback that it is not possible to energize the aluminum wiring sufficiently. If the solder material is not sufficiently in contact with the aluminum wiring, the resistance value increases.

When such a junction structure is used for an IC tag antenna described in Patent Document 3, for example, there are about 1 to 3 junctions between the aluminum wiring and the electrodes, and an increase in resistance is not a big problem. However, in the solar cell modules described in Patent Documents 1 and 2, for example, the electrodes of 20 to 30 solar cells are connected in series by an aluminum wiring via a conductive connection member. Large and current consumption increases.
Further, the contact resistance was not stable even when the gap between the aluminum wiring and the electrode was reduced.
Further, when a silver paste containing silver particles is used as the conductive connecting member, the silver particles generally have a particle size as small as 10 to 20 μm. Therefore, when the height of the silver paste is formed to be several hundred μm, the silver particles are connected. May become unstable and the conductivity may deteriorate.

  In the present invention, a conductive member connection structure capable of obtaining good conductivity by reducing and stabilizing the contact resistance between the aluminum wiring and the conductive connection unit, a metal foil pattern laminate including the connection structure, and A solar cell module is provided.

The connection structure of the conductive member includes an aluminum wiring and a conductive connection unit that conducts by connecting the aluminum wiring to the conductive unit, and the conductive connection unit includes at least a plurality of fine silver particles that contact the aluminum wiring. And conductive metal particles that are in contact with a plurality of fine silver particles and extend longer than the silver particles in the direction from the aluminum wiring toward the conductive unit.
The conductive unit refers to an electrode in the present application as exemplified in the embodiments described later, but may be another component such as a resistor or an integrated circuit, or a conductive material such as a wiring member.
As the conductive connection unit, the plurality of silver particles of the first silver paste and the conductive metal particles can be sequentially brought into contact with the aluminum wiring to be conductive. Further, the silver particles ensure a large contact area between the aluminum wiring and the conductive metal particles. Further, the conductive metal particles are longer and longer than the silver particles in the direction from the aluminum wiring toward the conductive unit. Therefore, the conductivity can be improved and the contact resistance can be reduced and stabilized as compared with the case where a plurality of conventional silver particles are brought into contact with each other.
In addition, if a fine silver particle is flat form, it is preferable when ensuring a contact area.

  The conductive metal particles are preferably columnar. If it is columnar, the number of connections in the length direction can be reduced as compared with the case where a plurality of conventional silver particles are used, and stable conductivity can be secured in the columnar axial direction.

The conductive metal particles may be copper, silver, nickel or any other conductive metal.
If the conductive metal particles are formed of copper, nickel or other conductive metal, the same conductivity as silver can be obtained and the cost is lower than that of silver. In particular, if it is made of silver, good conductivity can be obtained.

The conductive metal particles are silver particles and may be contained in the first silver paste.
When the conductive metal particles are contained in the first silver paste containing a plurality of fine silver particles, the conductive metal particles are made of aluminum by pressing the first silver paste with the aluminum wiring and the conductive unit. The silver particles that are in surface contact with the wiring can be laminated in surface contact. Therefore, the contact resistance is small and stable, and the conductivity is good.
Alternatively, the conductive metal particles are silver particles and may be included in the second silver paste.
When the conductive metal particles are contained in a second silver paste different from the first silver paste, by applying the second silver paste to the first silver paste applied to the aluminum wiring, The conductive metal particles can be laminated while being surely brought into surface contact with the silver particles in surface contact with the aluminum wiring. Accordingly, as described above, the contact resistance is small and stable, and the conductivity is good.

The conductive metal particles may be a plate-like member formed by punching.
By placing the plate-like conductive metal particles formed by punching on the silver particles that are in contact with the aluminum wiring, it is possible to reliably stack them.

Further, a third silver paste containing fine silver particles may be interposed between the conductive metal particles and the conductive unit to conduct electricity.
Contact between the aluminum wiring and the conductive unit by bringing the conductive metal particles into contact with the silver particles of the first silver paste and then contacting the conductive unit through the silver particles of the third silver paste. Resistance can be stabilized and conductivity can be improved.

The connection structure of the conductive member includes an aluminum wiring and a conductive connection unit that connects the aluminum wiring to the conductive unit to conduct electricity, and the conductive connection unit includes a first silver paste containing a plurality of silver particles. Thus, the aluminum wiring has a concavo-convex portion for fitting and conducting silver particles.
The aluminum wiring and the conductive unit are made conductive by bringing a plurality of silver particles contained in the first silver paste into contact with each other. Further, by fitting the silver particles into the concavo-convex portion provided on the aluminum wiring, the contact between the aluminum wiring and the silver particles can be ensured, and the contact resistance can be made small and stable and conductive.

The metal foil pattern laminate includes any of the conductive member connection structures described above and a substrate to which aluminum wiring is bonded via an adhesive layer.
Thereby, a contact with an aluminum wiring and an electroconductive unit can be ensured, and contact resistance can be stabilized small.

A solar cell module includes a connection structure of any of the above-described conductive members, a substrate to which aluminum wiring is bonded via an adhesive layer, a solar cell provided with an electrode as a conductive unit on the back surface, A sealing material that seals the battery cells; and a translucent front plate that is laminated on the surface opposite to the aluminum wiring with respect to the sealing material.
By photoelectrically converting the light received by the solar cell through the translucent front plate, the electrode of the solar cell, the conductive connection unit, and the aluminum wiring are securely brought into contact in this order to conduct the contact resistance. Small and stable.

  According to the connection structure of the conductive member of the present application, by making silver particles and conductive metal particles of the first silver paste sequentially contact and conduct as a conductive connection unit to the aluminum wiring, The contact area between the aluminum wiring and the conductive metal particles is ensured. The conductive metal particles extend longer than the silver particles in the direction from the aluminum wiring in the conductive connection unit toward the conductive unit. Therefore, compared with the case where the conventional several silver particle is made to contact, contact resistance can be stabilized small and electroconductivity can also be improved.

  In addition, according to the conductive member connection structure of the present application, the conductive connection unit includes the first silver paste including a plurality of fine silver particles in contact with the aluminum wiring, and the fine silver particles are fitted into the aluminum wiring. Concave and convex portions are formed. Therefore, the aluminum wiring and the fine silver particles contained in the first silver paste are brought into contact with each other, the contact resistance is reduced and stabilized, and the conductivity can be improved.

  The metal foil pattern laminate of the present application can improve the electrical conductivity by making the contact between the aluminum wiring and the conductive connection unit reliable, making the contact resistance small and stable by the connection structure of the conductive member.

  The solar battery module of the present application photoelectrically converts the light received by the solar battery cell, and makes sure that the electrode of the solar battery cell, the conductive connection unit, and the aluminum wiring are brought into surface contact in this order with certainty and conductive. Thus, the contact resistance can be made small and stable, and the conductivity can be improved.

It is sectional drawing which isolate | separates and shows the solar cell module by 1st embodiment of this application. It is a principal part expanded sectional view which shows the junction structure of the aluminum wiring in the solar cell module shown in FIG. 1, and the electrode of a photovoltaic cell. It is a principal part expanded sectional view which shows the connection structure between the aluminum wiring by the second embodiment of this application, and the electrode of a photovoltaic cell. It is a principal part expanded sectional view which shows the connection structure between the aluminum wiring by 3rd embodiment of this application, and the electrode of a photovoltaic cell. It is a principal part expanded sectional view which shows the connection structure between the aluminum wiring by 4th embodiment of this application, and the electrode of a photovoltaic cell. It is a principal part expanded sectional view which shows the connection structure between the aluminum wiring by the modification of 1st embodiment of this application, and the electrode of a photovoltaic cell. It is sectional drawing which shows the principal part structure of the conventional solar cell module. It is sectional drawing which shows the wiring pattern provided in the conventional solar cell backsheet.

Hereinafter, a solar cell module provided with a conductive member connection structure according to each embodiment will be described with reference to FIGS. 1 and 6.
First Embodiment A solar cell module 1 including a conductive member connection structure according to a first embodiment shown in FIG. 1 includes a metal foil pattern laminate 2 and a back sheet 3 provided on the back surface of the metal foil pattern laminate 2. A plurality of solar cells 4 arranged on the surface of the metal foil pattern laminate 2, a sealing material 5 for sealing the plurality of solar cells 4 on the metal foil pattern laminate 2, and a sealing material And a translucent front plate 6 provided on the surface of 5.

The back sheet 3 has a barrier layer as a shield material. As the barrier layer of the back sheet 3, an aluminum foil film or a composite laminated film of the aluminum foil film and the resin material of the base material 8 having a moisture shielding property and an oxygen shielding property can be used.
The metal foil pattern laminate 2 is formed by laminating an insulating base material 8 bonded to the back sheet 3, an adhesive layer 9, and an aluminum wiring 10 as a metal foil pattern on which a predetermined circuit pattern is formed. Has been.

The base material 8 has a film shape or a sheet shape. As the material, for example, acrylic, polycarbonate, polyethylene terephthalate, polyethylene naphthalate, polyimide, urethane, epoxy, melamine, styrene, or a resin obtained by copolymerization thereof can be used. In order to control heat insulation, elasticity, and optical characteristics, an organic or inorganic filler or the like may be mixed in the base material 8 as necessary.
The adhesive layer 9 is formed, for example, by heating and curing a thermosetting resin such as urethane, acrylic, epoxy, polyimide, olefin, or a step curable adhesive obtained by copolymerizing these. Moreover, you may use the adhesive bond layer which is not a step hardening type as the adhesive bond layer 3. FIG.

The aluminum wirings 10 are arranged with a predetermined gap therebetween, and an insulating resin 12 is disposed in the gaps between the aluminum wirings 10. The aluminum wiring 10 has a predetermined wiring pattern. An oxide film containing alumina Al ₂ O ₃ is easily formed on the surface 10 a of the aluminum wiring 10. Therefore, the flat silver particles 21 of the conductive connection unit 15 described later have better conductivity than the above-described solder material, but on the other hand, the resistance value increases because it is difficult to adhere. Although this resistance value is insignificant, in the solar cell module 1, since a large number of solar cells 4 are connected in series, the overall resistance value increases.
Therefore, it is desirable to remove the oxide film on the surface 10 a of the aluminum wiring 10 for electrical connection with the electrode 13 disposed on the back surface of the solar battery cell 4. In order to prevent the oxide film from being formed again on the surface 10a of the aluminum wiring 10 after the oxide film is removed, for example, an antioxidant film such as a hexavalent chromium-free surface treatment agent for aluminum (“Palcoat” manufactured by Nihon Parkerizing Co., Ltd.) It is preferable to form.

For example, an EVA film is used as the sealing material 5 that seals and insulates the solar cells 4. The sealing material 5 may be formed by laminating two or more EVA films so as to sandwich the solar battery cell 4. Further, for example, a glass panel is used for the translucent front plate 6 bonded to the surface of the sealing material 5.
Although the above-described solar cell module 1 is a final product, a laminate from the back sheet 3 to the metal foil pattern laminate 2 including the aluminum wiring 10 (and the insulating resin 12) may be shipped as a product. A conductive connection unit 15 may also be included.
In addition, although the metal foil pattern laminated body 2 was illustrated as lamination | stacking with the base material 8, the adhesive bond layer 9, and the aluminum wiring 10, the aluminum wiring 10 was directly provided on the base material 8, and the adhesive bond layer 9 was used. Arbitrary combinations are possible, such as a configuration in which the aluminum wiring 10 is provided on the back sheet 3 and the base material 8 is not used.
Moreover, it is also possible to constitute the solar cell module 1 or the metal foil pattern laminate 2 without using the insulating resin 12 and / or the backsheet 3.

Next, the connection structure of the electroconductive member which is 1st embodiment of this application used with the solar cell module 1 is demonstrated with reference to FIG.
In the connection structure between the aluminum wiring 10 and the electrode 13 of the solar battery cell 4 according to the present embodiment shown in FIG. 2, solder is generally used as the conductive connection unit 15 that connects the aluminum wiring 10 and the electrode 13. It was done. However, when the aluminum wiring 10 is used as the wiring pattern, it is difficult for the solder to adhere to the aluminum wiring 10 and the electrical resistance increases. Therefore, a silver paste 17 is used as the conductive connection unit 15.
In addition, the aluminum wiring 10, the conductive connection unit 15, and the electrode 13 of the solar battery cell 4 constitute a conductive member, and the bonding structure is the aluminum wiring 10 and the conductive connection unit 15, or the aluminum wiring 10, the conductive connection unit. 15 and the junction structure of the electrode 13 of the solar battery cell 4.

A gap K between the aluminum wiring 10 and the electrode 13 of the solar battery cell 4 is, for example, about 400 micrometers (μm). When the silver paste 17 is disposed and electrically connected to the gap K between the aluminum wiring 10 and the electrode 13 of the solar battery cell 4, the silver particles contained in the synthetic resin 18 generally have, for example, a particle size of 10 to 10. It is as fine as about 20 μm. Further, when the content ratio is, for example, 80% by weight of silver particles and 20% by weight of synthetic resin, the ratio of silver particles is lower than the weight ratio in volume ratio. Therefore, since the contact ratio between silver particles becomes small, the resistance value during energization is large and unstable.
The solar cell module 1 has a configuration in which, for example, about 20 to 30 solar cells 4 are connected in series. Therefore, in order to prevent the contact resistance value from increasing and the power generation efficiency from decreasing, it is necessary to reduce the contact resistance of the conductive connection unit 15.
On the other hand, if the particle diameter of a large number of silver particles is formed to be, for example, about 100 to 200 μm, the contact area increases and the resistance value during energization decreases. However, since such large-diameter silver particles are not generally produced, the production cost increases.

Therefore, in the first embodiment of the present application, in the connection structure of conductive members, the following configuration is adopted in order to suppress an increase in manufacturing cost of silver particles, increase a contact area, and reduce electric resistance.
That is, in the connection structure of the aluminum wiring 10 and the electrode 13 of the solar battery cell 4 according to the first embodiment of the present application, as shown in FIG. 2, the silver paste 17 is composed of a large number of silver in a synthetic resin 18 having viscosity and fluidity. A paste in which particles are dispersed and mixed. The silver particles include, for example, long and large pillar silver particles 20 having a pillar shape and a height of about 400 μm, and flat silver particles 21 having a substantially plate shape and fine (for example, about 10 to 20 μm).
The synthetic resin 18 includes, for example, an epoxy resin or a silicon resin.

In the silver paste 17, a plurality of fine tabular silver particles 21 are arranged in contact with the surface of the aluminum wiring 10, and the pillar silver particles 20 are in contact between the tabular silver particles 21 and the electrodes 13 of the solar battery cell 4. Arranged. The aluminum wiring 10 is formed with an antioxidant coating by removing the oxide coating on the surface 10a. This also reduces the contact resistance value and improves the conductivity.
With the above configuration, electricity is passed between the aluminum wiring 10 and the electrode 13 of the solar battery cell 4 through the plate-like fine silver particles 21 and the pillar silver particles 20. Moreover, since the electrode 13 of the solar battery cell 4 is made of silver, the conductivity is good.

In order to join the flat silver particles 21 and the pillar silver particles 20 contained in the synthetic resin 18 with respect to the silver paste 17 disposed in the gap K between the aluminum wiring 10 and the electrode 13 of the solar battery cell 4 as described above, The following manufacturing method is used.
A silver paste 17 in which pillar silver particles 20 and flat silver particles 21 are mixed in a synthetic resin 18 is manufactured, this silver paste 17 is applied on the aluminum wiring 10, and the electrodes 13 of the solar cells 4 are disposed thereon. To do. When pressure is applied to the silver paste 17 with the aluminum wiring 10 and the electrode 13 of the solar battery cell 4, for example, only one large pillar silver particle 20 is formed between the aluminum wiring 10 and the electrode 13 of the solar battery cell 4 by the pressing force. A plurality of fine tabular silver particles 21 remain in a flat plate shape between the pillar silver particles 20 and the aluminum wiring 10, and are in surface contact with each other.
Furthermore, by heating, the aluminum wiring 10, the plurality of tabular silver particles 21, the pillar silver particles 20, and the electrode 13 are in surface contact in this order and joined.

As described above, the conductive member connection structure in the solar cell module 1 according to the first embodiment presses and solidifies the silver paste 17 applied to the gap K between the aluminum wiring 10 and the electrode 13. Thereby, a plurality of fine flat silver particles 21 and pillar silver particles 20 can be sequentially laminated on the conductive film on the surface 10 a of the aluminum wiring 10 and brought into surface contact with the electrode 13 of the solar battery cell 4. Further, the resistance value can be further stabilized by removing the oxide film on the surface 10a of the aluminum wiring 10 to form a conductive film.
With the configuration in which columnar pillar silver particles 20 are formed longer than the flat silver particles 21 in the height direction within the gap K between the aluminum wiring 10 and the electrode 13, the aluminum wiring 10, the plurality of flat silver particles 21, the flat silver particles 21, The contact area between the lower end surface of the pillar silver particle 20 and the upper end surface of the pillar silver particle 20 and the electrode 13 can be ensured by surface contact. Accordingly, the contact resistance and current consumption are reduced, the resistance value is stabilized, and the conductivity is improved.

Furthermore, by providing columnar pillar silver particles 20 having a large height and arranging a plurality of fine flat silver particles 21 between the pillar silver particles 20 and the aluminum wiring 10, the contact resistance is reduced and the conductivity is reduced. Since it improved, the number of the big pillar silver particles 20 reduces, and the raise of manufacturing cost can be suppressed.
Therefore, in the solar cell module 1, even if, for example, several tens of aluminum wires 10 and the electrodes 13 of the solar cells 4 are connected in series with the silver paste 17, the resistance value increases and the current consumption increases. Can be suppressed.

In addition, the connection structure of the conductive member in the solar cell module 1 of the present application is not limited to the above-described first embodiment, and the configuration, material, and the like can be changed or replaced as appropriate without departing from the gist of the present invention. And these are also included in the present application.
Although other embodiments and modifications of the present application will be described below, the same or similar members and components as those of the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.

2nd embodiment The connection structure of the electroconductive member of the solar cell module 1 by 2nd embodiment of this application is demonstrated with FIG.
In the connection structure between the aluminum wiring 10 and the electrode 13 of the solar battery cell 4 according to the second embodiment, the conductive connection unit 15 is replaced with the first silver paste 23 containing the flat silver particles 21 and the pillar silver particles as shown in FIG. The second silver paste 24 containing 20 is formed into two layers.

First, a first silver paste 23 in which a plurality of fine flat silver pastes 21 are mixed in a synthetic resin 18 is applied on the surface 10a of the aluminum wiring 10 on which an antioxidant coating is formed. Next, the 2nd silver paste 24 which mixed the pillar silver particle 20 in the synthetic resin 18 is apply | coated on the 1st silver paste 23, and the electrode 13 of the photovoltaic cell 4 is adhere | attached on it. Furthermore, by heating, the aluminum wiring 10, the plurality of tabular silver particles 21, the pillar silver particles 20, the plurality of tabular silver particles 21, and the electrode 13 are brought into surface contact in this order and bonded.
According to the conductive member connection structure according to the second embodiment, a plurality of fine flat silver pastes 21 and pillar silver pastes 20 are sequentially laminated in the gap K between the aluminum wiring 10 and the electrode 13 of the solar battery cell 4. By making surface contact with each other, the aluminum wiring 10 and the electrode 13 of the solar battery cell 4 can be reliably made conductive.
Moreover, since the conductive connection unit 15 is formed in two layers, in the pressing method according to the first embodiment, the lamination of the tabular silver particles 21 and the pillar silver particles 20 can be more reliably formed.

  In the first and second embodiments described above, as the conductive connection member 15 that connects the aluminum wiring 10 and the electrode 13 of the solar battery cell 4, fine flat silver particles 21 and a large pillar on the aluminum wiring 10. Silver particles 20 were laminated. The connection between the upper end surface of the pillar silver particle 20 and the electrode 13 of the solar battery cell 4 has good conductivity because the electrode 13 is made of silver. However, in order to further ensure the contact and energization between the pillar silver particles 20 and the electrode 13, the surface of the electrode 13 is the same as the first silver paste 23 in which fine flat silver particles 21 are mixed in the synthetic resin 18. You may apply | coat the 3rd silver paste of a structure.

3rd embodiment The connection structure of the electroconductive member of the solar cell module 1 by 3rd embodiment of this application is demonstrated with FIG.
In the third embodiment, in the connection structure between the aluminum wiring 10 of the solar battery module 1 and the electrode 13 of the solar battery cell 4, the conductive connection unit 15 is replaced with two first silver pastes 23 including flat silver particles 21, The third silver paste 23A and the pillar metal particles 26 disposed therebetween were formed in three layers.

That is, the first silver paste 23 in which the fine flat silver paste 21 is mixed in the synthetic resin 18 is applied to the surface 10a of the aluminum wiring 10 on which the antioxidant coating is formed. On the upper surface of the flat silver paste 21 of the first silver paste 23 provided on the aluminum wiring 10, columnar pillar metal particles 26 formed of, for example, copper, Ni, or other various conductive metals are disposed.
Then, the third silver paste 23 </ b> A is applied to the electrode 13 of the solar battery cell 4 and disposed on the upper end surface of the pillar metal particle 26. When the pillar metal particles 26 are formed of a conductive metal other than silver, for example, copper, if the flat silver particles 21 are placed between the pillar metal particles 26 and the electrode 13, good conductivity can be obtained.

According to the connection structure of conductive members according to the third embodiment, fine tabular silver particles 21, pillar metal particles 26, and tabular silver particles 21 are formed in the gap K from the aluminum wiring 10 to the electrode 13 of the solar battery cell 4. Are stacked in contact with each other so as to form three layers in this order. Furthermore, the aluminum wiring 10 and the electrode 13 of the solar battery cell 4 can be formed in a conductive state by heating.
The pillar metal particles 26 have a thickness of about 400 μm and a substantially plate shape. Therefore, for example, a film-like conductive metal such as copper or Ni may be punched out by punching and placed on the flat silver particles 21 on the surface 10 a of the aluminum wiring 10.

According to the connection structure of the conductive member in the solar cell module 1 according to the third embodiment, the flat silver particles 21, the pillar metal particles 26, and the flat plates are provided between the aluminum wiring 10 and the electrodes 13 of the solar cells 4. Silver particles 21 are laminated in this order in three layers and are brought into surface contact with each other. Therefore, the contact resistance value between the aluminum wiring 10 and the solar battery cell 4 can be reduced and the conductivity can be improved.
In addition, the pillar metal particles 26 having a height higher than that of the tabular silver particles 21 are formed of an inexpensive conductive metal such as copper or Ni instead of expensive silver, and the tabular silver particles 21 are formed with fine dimensions having general dimensions. Since it was formed using simple silver particles, it can be manufactured at a lower cost.
The pillar metal particles 26 may be formed of silver.

Fourth Embodiment A connection structure for conductive members of a solar cell module 1 according to a fourth embodiment of the present application will be described with reference to FIG.
In the connection structure between the aluminum wiring 10 and the conductive connection unit 15 according to the fourth embodiment, a silver paste 29 is applied as the conductive connection unit 15 to the gap K between the aluminum wiring 10 and the electrode 13 of the solar battery cell 4. And heated to join. The silver paste 29 is formed by mixing a large number of fine silver particles 28 having a particle size of, for example, about 10 to 20 μm in the synthetic resin 18. As described above, the content ratio included in the silver paste 29 is, for example, 80% by weight for the silver particles 28 and 20% by weight for the synthetic resin 18 in terms of weight ratio.
On the surface 10a of the aluminum wiring 10, a plurality of fine recesses 30 into which silver particles 28 can be fitted are formed as uneven portions. Therefore, the roughness (Rz value) of the concavo-convex portion of the surface 10a of the aluminum wiring 10 is formed to be substantially the same as the particle size of the silver particles 28 so that the silver particles 28 enter the concave portions 30 of the surface 10a. The particle size of the silver particles 28 is not necessarily uniform and may be indefinite, and the center value of the particle size distribution may be substantially the same as the roughness (Rz value) of the uneven portion.

  On the surface 10a of the aluminum wiring 10, the oxide film may be removed to form an anti-oxidation film in the same manner as in each of the above-described embodiments. Thus, the oxide film may be removed.

  As described above, according to the conductive member connecting structure in the solar cell module 1 according to the fourth embodiment, the silver paste in which the aluminum wiring 10 and the electrode 13 of the solar cell 4 are applied to the gap K between them. 29 is brought into a conducting state by the contact of a large number of silver particles 28 included in the material 29. In addition, by fitting the silver particles 28 into the concave portions 30 of the concavo-convex portions formed on the surface 10 a of the aluminum wiring 10, the aluminum wiring 10 and the silver particles 28 can be brought into electrical contact with each other sufficiently. Further, since the electrode 13 is made of silver, it is in sufficient contact with the silver particles 28 of the silver paste 29, and therefore can be reliably conducted.

In addition, in each embodiment of this application mentioned above, although the connection structure from the aluminum wiring 10 to the electrode 13 of the photovoltaic cell 4 was demonstrated as a connection structure of an electroconductive member, this application is not limited to the connection structure mentioned above, It can replace with the electrode 13 of the photovoltaic cell 4, and can also be used for the connection structure of electroconductive units, such as another circuit, and the aluminum wiring 10. FIG.
Moreover, the connection structure of the electroconductive member by each embodiment of this application can also be used not only for the solar cell module 1, but for the connection structure of various electroconductive members, such as an antenna of an IC tag, a conductor, and a circuit pattern. .

In the conductive connection unit 15 in the first embodiment, instead of one pillar silver particle 20 as shown in FIG. 2, a plurality of pillar silver particles 20A are dispersed or contacted in parallel as shown in FIG. It may be arranged. This configuration can also be used for the pillar silver particles 20 and the pillar metal particles 26 in the second and third embodiments.
The pillar silver particles 20 and the pillar metal particles 26 form conductive metal particles.
The fine silver particles 21 and 28 contained in the silver pastes 17, 23, and 29 are not necessarily flat and may be indefinite.

  Further, in each of the above-described embodiments, the oxide film on the surface 10a of the aluminum wiring 10 is removed to form the antioxidant film and the conductivity is ensured. However, it is not always necessary to remove the oxide film. For example, in an IC tag antenna or the like, the silver paste used for energization with the conductive connection member 15 is very small, for example, about 1 to 3, so that the conductive connection member 15 is made conductive through an oxide film. Good.

  A conductive member connection structure in which an aluminum wiring and a conductive connection member are connected, a metal foil pattern laminate including the connection structure, and solar cells connected to the metal foil pattern laminate and sealed. Applicable to solar cell modules.

DESCRIPTION OF SYMBOLS 1 Solar cell module 2 Metal foil pattern laminated body 4 Solar cell 5 Sealing material 6 Translucent front board 10 Aluminum wiring 10a Surface 13 Electrode 15 Conductive connection member 17, 29 Silver paste 18 Synthetic resin 20 Pillar silver particle 21 Flat plate Silver particles 23 First silver paste 23A Third silver paste 24 Second silver paste 26 Pillar metal particles 28 Silver particles

Claims (10)

An aluminum wiring, and a conductive connection unit for connecting the aluminum wiring to a conductive unit to conduct electricity;
The conductive connection unit includes at least a first silver paste including a plurality of fine silver particles that are in contact with the aluminum wiring, and is in contact with the plurality of silver particles and in a direction from the aluminum wiring to the conductive unit. Conductive metal particles extending longer than the silver particles,
Conductive member connection structure.   The conductive member connection structure according to claim 1, wherein the conductive metal particles are columnar.   The conductive member connection structure according to claim 1, wherein the conductive metal particles are copper, silver, nickel, or another conductive metal.   The conductive member connection structure according to claim 1, wherein the conductive metal particles are silver particles and are included in the first silver paste.   The conductive metal connection structure according to claim 1, wherein the conductive metal particles are silver particles and are contained in a second silver paste.   The conductive member connection structure according to claim 1, wherein the conductive metal particles are plate-like members formed by punching.   The conductive member according to any one of claims 1 to 6, wherein a third silver paste containing fine silver particles is interposed between the conductive metal particles and the conductive unit to conduct electricity. Connection structure. An aluminum wiring, and a conductive connection unit for connecting the aluminum wiring to a conductive unit to conduct electricity;
The conductive connection unit comprises a first silver paste containing a plurality of silver particles,
The aluminum wiring has a concavo-convex portion for fitting and conducting the silver particles,
Conductive member connection structure. The connection structure of the conductive member according to any one of claims 1 to 8,
A substrate to which the aluminum wiring is bonded via an adhesive layer;
A metal foil pattern laminate. The connection structure of the conductive member according to any one of claims 1 to 8,
A substrate to which the aluminum wiring is bonded via an adhesive layer;
A solar battery cell provided with an electrode on the back surface, which is the conductive unit;
A sealing material for sealing the solar battery cell;
A translucent front plate laminated on the surface opposite to the aluminum wiring with respect to the sealing material;
A solar cell module comprising:

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