Hitachi, Ltd. : Patent Application Titled “Conductive Binder Composition, Metal Wire with Conductive Binder, Bonded Unit, and Solar Cell Module” Published Online
《Hitachi, Ltd. : Patent Application Titled “Conductive Binder Composition, Metal Wire with Conductive Binder, Bonded Unit, and Solar Cell Module” Published Online》：
By a News Reporter-Staff News Editor at Politics & Government Week — According to news reporting originating from Washington, D.C., by VerticalNews journalists, a patent application by the inventors Yokochi,Seigo (Hitachi-shi, JP); Fujita, Masaru (Hitachi-shi, JP); Hayashi, Hiroki (Tsukuba-shi, JP), filed on January 11, 2012, was made available online onDecember 26, 2013.
The assignee for this patent application is Hitachi Chemical Company, Ltd.
Reporters obtained the following quote from the background information supplied by the inventors: “As means for solving aggravated global warming or fossil energy depletion, attention is paid on a solar battery which is a power generating system using sunlight. A structure in which solar battery cells in which an electrode is formed on a monocrystalline or polycrystalline Si wafer, are connected in series or in parallel to each other via a metal wire, has been employed for the current main solar battery cells. In general, solder which shows excellent conductivity and is inexpensive has been used for the connection of the electrodes of the solar battery cells and the metal wire (Patent Literature 1). Further, in recent years, in consideration of environmental problems, a method has been known for applying Sn–Ag–Cu solder which does not contain Pb onto a copper wire which is a metal wire, and connecting electrodes of solar battery cells and the metal wire by performing heating to a temperature equal to or higher than a melting temperature of the solder (Patent Literature 1 and 2).
“However, at the time of the connecting, since it is necessary to perform heating at a temperature equal to or higher than 260.degree. C. which exceeds a melting point of the Sn–Ag–Cu solder, in addition to an occurrence of property degradation of the solar battery cells, there are problems that warping or cracking of solar battery cells is generated and yield ratio is degraded.
“For solving such problems, a use of a conductive adhesive composition capable of electrical connection at a lower temperature has been proposed (Patent Literature 3). This conductive adhesive composition is a composition obtained by mixing and dispersing of metal particles which are typified by silver particles in a thermosetting resin, and the electrical connection is expressed by physical contacting with these metal particles to the electrodes of the solar battery cells and the metal wire.
“In addition, an adhesive which contains a thermosetting resin as an alternative material of the solder, metal particles such as lead-free solder melting at a low temperature and flux, and has a low melting temperature, excellent wettability, and high binding strength has been proposed (Patent Literature 4).”
In addition to obtaining background information on this patent application, VerticalNews editors also obtained the inventors’ summary information for this patent application: “Technical Problem
“However, since the conductivity expressing mechanism of the conductive adhesive composition disclosed in Patent Literature 3 is realized based on the contact of metal particles, it is necessary to increase content of the metal particles for securing excellent conductivity. As a result, adhesiveness of the adhesive is degraded according to the reduction of the adhesive components.
“In addition, in a case of using the conductive adhesive composition disclosed in Patent Literature 4 for producing a solar cell module, the present inventors have found that there is a problem that it is difficult to handle the conductive adhesive composition, since the adhesive has tackiness.
“Herein, an object of the present invention is to provide a conductive adhesive composition which does not have tackiness at a room temperature and is capable of electrical connection at a low temperature, and a metal wire with a conductive adhesive using the composition. In addition, another object thereof is to provide a connected body and a solar cell module using the conductive adhesive composition or the metal wire with a conductive adhesive.
“In addition, in the present specification, the phrase of ‘does not have tackiness’ means that the tackiness is not recognized as a result of a predetermined test disclosed in Examples.
“Solution to Problem
“The present invention provides a conductive adhesive composition including: conductive particles (A) containing metal having a melting point of equal to or lower than 210.degree. C. (hereinafter, also simply referred to as ‘conductive particles (A)’); a resin (B) having a softening point of equal to or lower than the melting point of the metal of the conductive particles and being solid at a room temperature (hereinafter, also simply referred to as a ‘resin (B)’); a flux activator (C); and a solvent (D).
“According to the conductive adhesive composition, by employing the configuration described above, it is possible to avoid the tackiness at a room temperature and to perform electrical connection at a low temperature.
“In addition, in the present specification, the ‘melting point’ refers to a value measured by Differential Scanning calorimetry (DSC), for example, and the ‘softening point’ refers to a value measured by a rheometer which can change a measurement temperature, for example.
“It is preferable that the metal of the conductive particles (A) contain at least one kind of component selected from bismuth, indium, tin, and zinc. Accordingly, it is possible to decrease the melting point of the conductive particles while maintaining excellent conductivity.
“From a viewpoint of obtaining excellent connection stability, it is preferable that the resin (B) contain a thermosetting resin, and particularly contain an epoxy resin.
“In a case where the conductive adhesive composition described above contains the thermosetting resin, it is preferable that the conductive adhesive composition further contain a curing agent or a curing accelerator.
“It is preferable that the flux activator (C) contain a compound having a hydroxy group and a carboxyl group.
“It is preferable that a boiling point of the solvent (D) be equal to or higher than 20.degree. C. and equal to or lower than 300.degree. C. Accordingly, it becomes easy to remove the solvent and it is possible to apply the conductive adhesive composition evenly on the electrode surfaces of the solar battery cells.
“The conductive adhesive composition described above may be suitably used for electrical connection of the electrodes of the solar battery cells and the metal wire.
“In addition, the present invention provides a connected body in which a plurality of solar battery cells are connected via a metal wire, in which electrodes of the solar battery cells and the metal wire are connected via the conductive adhesive composition described above.
“In addition, the present invention provides a metal wire with a conductive adhesive formed of a metal wire and an adhesive layer coating the metal wire, in which the adhesive layer is formed of an adhesive using the conductive adhesive composition described above.
“In addition, the present invention provides a connected body formed of a plurality of solar battery cells, and a metal wire with a conductive adhesive which is disposed on electrode surfaces of the solar battery cells and is for electrical connection of the plurality of solar battery cells, in which the metal wire with a conductive adhesive is the metal wire with a conductive adhesive described above.
“In addition, the present invention provides a method for producing a solar cell module including: a step of laminating a sealing material on both surfaces of the connected body described above; a step of laminating glass on the sealing material on a light receiving surface side of the solar battery cells, and a protection film on the sealing material on a rear surface of the solar battery cells; and a step of sealing the solar battery cells while electrically connecting and bonding the solar battery cells and the metal wires by heating the obtained laminated body.
“In addition, the present invention provides a solar cell module in which electrodes of a plurality of solar battery cells and metal wire are electrically connected to via the conductive adhesive composition described above.
“Advantageous Effects of Invention
“According to the present invention, it is possible to provide a conductive adhesive composition which does not have tackiness at a room temperature and is capable of electrical connection at a low temperature, and the metal wire with a conductive adhesive using the composition. In addition, by using the conductive adhesive composition or the metal wire with a conductive adhesive, it is possible to provide a connected body which realizes shortening and simplicity of process at the time of producing the solar cell module. Further, by using the conductive adhesive composition which is capable of electrical connection at a low temperature or the metal wire with a conductive adhesive, it is possible to provide a solar cell module having high reliability.
BRIEF DESCRIPTION OF DRAWINGS
“FIG. 1 is a schematic view showing main parts of a solar cell module according to the present invention.
“FIG. 2 is a view for illustrating one embodiment of a method for producing a solar cell module according to the present invention.”
For more information, see this patent application: Yokochi, Seigo; Fujita,Masaru; Hayashi, Hiroki. Conductive Binder Composition, Metal Wire with Conductive Binder, Bonded Unit, and Solar Cell Module. Filed January 11, 2012 and posted December 26, 2013. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=6395&p=128&f=G&l=50&d=PG01&S1=20131219.PD.&OS=PD/20131219&RS=PD/20131219
Keywords for this news article include: Energy, Solar Cell, Hitachi Chemical Company Ltd..
Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2014, NewsRx LLC
《Hitachi, Ltd. : Patent Application Titled “Conductive Binder Composition, Metal Wire with Conductive Binder, Bonded Unit, and Solar Cell Module” Published Online》：
By a News Reporter-Staff News Editor at Politics & Government Week — According to news reporting originating from Washington, D.C., by VerticalNews journalists, a patent application by the inventors Yokochi,Seigo (Hitachi-shi, JP); Fujita, Masaru (Hitachi-shi, JP); Hayashi, Hiroki (Tsukuba-shi, JP), filed on January 11, 2012, was made available online onDecember 26, 2013.
The assignee for this patent application is Hitachi Chemical Company, Ltd.
Reporters obtained the following quote from the background information supplied by the inventors: “As means for solving aggravated global warming or fossil energy depletion, attention is paid on a solar battery which is a power generating system using sunlight. A structure in which solar battery cells in which an electrode is formed on a monocrystalline or polycrystalline Si wafer, are connected in series or in parallel to each other via a metal wire, has been employed for the current main solar battery cells. In general, solder which shows excellent conductivity and is inexpensive has been used for the connection of the electrodes of the solar battery cells and the metal wire (Patent Literature 1). Further, in recent years, in consideration of environmental problems, a method has been known for applying Sn–Ag–Cu solder which does not contain Pb onto a copper wire which is a metal wire, and connecting electrodes of solar battery cells and the metal wire by performing heating to a temperature equal to or higher than a melting temperature of the solder (Patent Literature 1 and 2).
“However, at the time of the connecting, since it is necessary to perform heating at a temperature equal to or higher than 260.degree. C. which exceeds a melting point of the Sn–Ag–Cu solder, in addition to an occurrence of property degradation of the solar battery cells, there are problems that warping or cracking of solar battery cells is generated and yield ratio is degraded.
“For solving such problems, a use of a conductive adhesive composition capable of electrical connection at a lower temperature has been proposed (Patent Literature 3). This conductive adhesive composition is a composition obtained by mixing and dispersing of metal particles which are typified by silver particles in a thermosetting resin, and the electrical connection is expressed by physical contacting with these metal particles to the electrodes of the solar battery cells and the metal wire.
“In addition, an adhesive which contains a thermosetting resin as an alternative material of the solder, metal particles such as lead-free solder melting at a low temperature and flux, and has a low melting temperature, excellent wettability, and high binding strength has been proposed (Patent Literature 4).”
In addition to obtaining background information on this patent application, VerticalNews editors also obtained the inventors’ summary information for this patent application: “Technical Problem
“However, since the conductivity expressing mechanism of the conductive adhesive composition disclosed in Patent Literature 3 is realized based on the contact of metal particles, it is necessary to increase content of the metal particles for securing excellent conductivity. As a result, adhesiveness of the adhesive is degraded according to the reduction of the adhesive components.
“In addition, in a case of using the conductive adhesive composition disclosed in Patent Literature 4 for producing a solar cell module, the present inventors have found that there is a problem that it is difficult to handle the conductive adhesive composition, since the adhesive has tackiness.
“Herein, an object of the present invention is to provide a conductive adhesive composition which does not have tackiness at a room temperature and is capable of electrical connection at a low temperature, and a metal wire with a conductive adhesive using the composition. In addition, another object thereof is to provide a connected body and a solar cell module using the conductive adhesive composition or the metal wire with a conductive adhesive.
“In addition, in the present specification, the phrase of ‘does not have tackiness’ means that the tackiness is not recognized as a result of a predetermined test disclosed in Examples.
“Solution to Problem
“The present invention provides a conductive adhesive composition including: conductive particles (A) containing metal having a melting point of equal to or lower than 210.degree. C. (hereinafter, also simply referred to as ‘conductive particles (A)’); a resin (B) having a softening point of equal to or lower than the melting point of the metal of the conductive particles and being solid at a room temperature (hereinafter, also simply referred to as a ‘resin (B)’); a flux activator (C); and a solvent (D).
“According to the conductive adhesive composition, by employing the configuration described above, it is possible to avoid the tackiness at a room temperature and to perform electrical connection at a low temperature.
“In addition, in the present specification, the ‘melting point’ refers to a value measured by Differential Scanning calorimetry (DSC), for example, and the ‘softening point’ refers to a value measured by a rheometer which can change a measurement temperature, for example.
“It is preferable that the metal of the conductive particles (A) contain at least one kind of component selected from bismuth, indium, tin, and zinc. Accordingly, it is possible to decrease the melting point of the conductive particles while maintaining excellent conductivity.
“From a viewpoint of obtaining excellent connection stability, it is preferable that the resin (B) contain a thermosetting resin, and particularly contain an epoxy resin.
“In a case where the conductive adhesive composition described above contains the thermosetting resin, it is preferable that the conductive adhesive composition further contain a curing agent or a curing accelerator.
“It is preferable that the flux activator (C) contain a compound having a hydroxy group and a carboxyl group.
“It is preferable that a boiling point of the solvent (D) be equal to or higher than 20.degree. C. and equal to or lower than 300.degree. C. Accordingly, it becomes easy to remove the solvent and it is possible to apply the conductive adhesive composition evenly on the electrode surfaces of the solar battery cells.
“The conductive adhesive composition described above may be suitably used for electrical connection of the electrodes of the solar battery cells and the metal wire.
“In addition, the present invention provides a connected body in which a plurality of solar battery cells are connected via a metal wire, in which electrodes of the solar battery cells and the metal wire are connected via the conductive adhesive composition described above.
“In addition, the present invention provides a metal wire with a conductive adhesive formed of a metal wire and an adhesive layer coating the metal wire, in which the adhesive layer is formed of an adhesive using the conductive adhesive composition described above.
“In addition, the present invention provides a connected body formed of a plurality of solar battery cells, and a metal wire with a conductive adhesive which is disposed on electrode surfaces of the solar battery cells and is for electrical connection of the plurality of solar battery cells, in which the metal wire with a conductive adhesive is the metal wire with a conductive adhesive described above.
“In addition, the present invention provides a method for producing a solar cell module including: a step of laminating a sealing material on both surfaces of the connected body described above; a step of laminating glass on the sealing material on a light receiving surface side of the solar battery cells, and a protection film on the sealing material on a rear surface of the solar battery cells; and a step of sealing the solar battery cells while electrically connecting and bonding the solar battery cells and the metal wires by heating the obtained laminated body.
“In addition, the present invention provides a solar cell module in which electrodes of a plurality of solar battery cells and metal wire are electrically connected to via the conductive adhesive composition described above.
“Advantageous Effects of Invention
“According to the present invention, it is possible to provide a conductive adhesive composition which does not have tackiness at a room temperature and is capable of electrical connection at a low temperature, and the metal wire with a conductive adhesive using the composition. In addition, by using the conductive adhesive composition or the metal wire with a conductive adhesive, it is possible to provide a connected body which realizes shortening and simplicity of process at the time of producing the solar cell module. Further, by using the conductive adhesive composition which is capable of electrical connection at a low temperature or the metal wire with a conductive adhesive, it is possible to provide a solar cell module having high reliability.
BRIEF DESCRIPTION OF DRAWINGS
“FIG. 1 is a schematic view showing main parts of a solar cell module according to the present invention.
“FIG. 2 is a view for illustrating one embodiment of a method for producing a solar cell module according to the present invention.”
For more information, see this patent application: Yokochi, Seigo; Fujita,Masaru; Hayashi, Hiroki. Conductive Binder Composition, Metal Wire with Conductive Binder, Bonded Unit, and Solar Cell Module. Filed January 11, 2012 and posted December 26, 2013. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=6395&p=128&f=G&l=50&d=PG01&S1=20131219.PD.&OS=PD/20131219&RS=PD/20131219
Keywords for this news article include: Energy, Solar Cell, Hitachi Chemical Company Ltd..
Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2014, NewsRx LLC