WO2013031702A1 - Method for manufacturing solar cell connecting structure - Google Patents

Method for manufacturing solar cell connecting structure Download PDF

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Publication number
WO2013031702A1
WO2013031702A1 PCT/JP2012/071497 JP2012071497W WO2013031702A1 WO 2013031702 A1 WO2013031702 A1 WO 2013031702A1 JP 2012071497 W JP2012071497 W JP 2012071497W WO 2013031702 A1 WO2013031702 A1 WO 2013031702A1
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WO
WIPO (PCT)
Prior art keywords
adhesive
connection structure
manufacturing
conductive particles
connection
Prior art date
Application number
PCT/JP2012/071497
Other languages
French (fr)
Japanese (ja)
Inventor
明典 横山
Original Assignee
旭化成イーマテリアルズ株式会社
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Publication of WO2013031702A1 publication Critical patent/WO2013031702A1/en

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/042—PV modules or arrays of single PV cells
    • H01L31/05—Electrical interconnection means between PV cells inside the PV module, e.g. series connection of PV cells
    • H01L31/0504—Electrical interconnection means between PV cells inside the PV module, e.g. series connection of PV cells specially adapted for series or parallel connection of solar cells in a module
    • H01L31/0512—Electrical interconnection means between PV cells inside the PV module, e.g. series connection of PV cells specially adapted for series or parallel connection of solar cells in a module made of a particular material or composition of materials
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
    • C09J11/02—Non-macromolecular additives
    • C09J11/04—Non-macromolecular additives inorganic
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J9/00—Adhesives characterised by their physical nature or the effects produced, e.g. glue sticks
    • C09J9/02—Electrically-conducting adhesives
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/20—Conductive material dispersed in non-conductive organic material
    • H01B1/22—Conductive material dispersed in non-conductive organic material the conductive material comprising metals or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/042—PV modules or arrays of single PV cells
    • H01L31/05—Electrical interconnection means between PV cells inside the PV module, e.g. series connection of PV cells
    • H01L31/0504—Electrical interconnection means between PV cells inside the PV module, e.g. series connection of PV cells specially adapted for series or parallel connection of solar cells in a module
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C08K3/08—Metals
    • C08K2003/0806—Silver
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C08K3/08—Metals
    • C08K2003/085—Copper
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K2201/00—Specific properties of additives
    • C08K2201/001—Conductive additives
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C08K3/08—Metals
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy

Definitions

  • the present invention relates to a connection structure, and more particularly, to a method for manufacturing a connection structure between a solar battery cell, a solar battery module and the like and a tab wire.
  • a solar cell module has a structure in which a plurality of solar cells are connected in series and / or in parallel via tab wires (wiring members) electrically connected to their surface electrodes. ing.
  • solder has been used to connect the surface electrode of the solar battery cell and the tab wire when manufacturing this solar battery module. Solder is widely used because it is excellent in connection reliability such as conductivity and fixing strength, is inexpensive, and is versatile.
  • Patent Document 1 the method using a conductive adhesive can be connected at a lower temperature than the method using a solder, and thus is suitable for electrical connection of thinned solar cells. It is thought that.
  • Patent Document 2 discloses a method for connecting thin solar cells.
  • an object of the present invention is to provide a connection structure that exhibits good connection conductivity and does not cause cracking of a substrate even in a thinned solar battery cell.
  • the present invention is as follows.
  • connection step including a connection step of connecting the surface electrode conductive wiring of the solar battery cell having a substrate thickness of 40 ⁇ m to 190 ⁇ m and the tab wire with an adhesive containing conductive particles having a Vickers hardness of 100 MPa to 600 MPa.
  • connection structure according to [1], wherein the conductive particles have an oxygen content of 10 ppm to 10,000 ppm.
  • connection structure according to [1] or [2], wherein the conductive particles are an alloy having a silver or copper component.
  • connection structure according to any one of [1] to [3], wherein the adhesive includes 0.1% by volume to 20% by volume of conductive particles.
  • connection structure according to any one of [1] to [4], wherein the adhesive includes a thermosetting resin and is pressurized and heated in the connection step.
  • a solar cell module including a connection structure manufactured by the manufacturing method according to any one of [1] to [5].
  • a method for producing a connection structure including a surface electrode conductive wiring of a solar battery cell, a tab wire, and a cured adhesive electrically connecting them the following steps: A method for producing the connection structure, comprising a step of setting the curing rate of the adhesive to 20% to 90% by curing the adhesive.
  • the light receiving part side of the solar battery cell is a convex surface, and the warpage of the convex surface at 50 ° C. is 0. 1 cm per length to the both ends of the tab wire.
  • connection structure according to [7] or [8], wherein the elastic modulus of the cured adhesive is 0.1 to 6.0 GPa.
  • connection structure according to any one of [7] to [9], wherein the solar cell substrate has a thickness of 40 ⁇ m to 190 ⁇ m.
  • connection structure that exhibits good connection conductivity and does not cause cracking of the substrate when the solar cell using a thin substrate and the wiring member are connected.
  • connection step of connecting the surface electrode conductive wiring of the solar battery cell having a substrate thickness of 40 ⁇ m to 190 ⁇ m and the tab wire with an adhesive containing conductive particles having a Vickers hardness of 100 MPa to 600 MPa A method for manufacturing a connection structure is provided.
  • connection structure containing the surface electrode conductive wiring of a photovoltaic cell, a tab line, and the hardened adhesive which has electrically connected them, Comprising: By hardening an adhesive, an adhesive There is also provided a method for producing the connection structure, which includes a step of setting the curing rate of 20% to 90%.
  • the solar battery cell in the present embodiment has a substrate and a surface electrode conductive wiring.
  • the thickness of the substrate is preferably 40 ⁇ m to 190 ⁇ m, more preferably 50 ⁇ m to 180 ⁇ m, and still more preferably 60 ⁇ m to 175 ⁇ m.
  • a thickness of the substrate of 190 ⁇ m or less is preferable from the viewpoint of performance and cost of the connection structure.
  • the thickness of the substrate is 40 ⁇ m or more, it is preferable from the viewpoint of utilization efficiency of sunlight.
  • the substrate examples include polycrystalline, single crystal, and amorphous silicon substrates, InGaAs substrates, GaAs substrates, CIGS substrates, and the like.
  • substrate a melting
  • the surface of the substrate can be roughened, an antireflection film can be applied, or a surface shaping process can be performed.
  • the substrate can be doped with a small amount of additive to make a pn junction.
  • the solar battery cell of this embodiment has a conductive wiring as a surface electrode on a substrate.
  • the width of the surface electrode conductive wiring is preferably 0.2 ⁇ m to 2 mm, and more preferably 10 ⁇ m to 1 mm.
  • the conductive wiring can be formed through holes or side surfaces from the front surface to the back surface of the substrate.
  • the thickness of the surface electrode conductive wiring is preferably 0.1 ⁇ m to 50 ⁇ m, and more preferably 0.1 ⁇ m to 30 ⁇ m.
  • the conductive wiring preferably includes at least one selected from the group consisting of silver, gold, copper, and aluminum. Furthermore, in the conductive bonding between the conductive wiring and the conductive particles, from the viewpoint of obtaining a stable connection by suppressing diffusion of the components forming the conductive wiring and / or conductive particles, the components of the conductive particles and the conductive wiring are: More preferably, they are identical or close to each other.
  • the adhesive forming the connection structure includes conductive particles and an organic binder.
  • the content ratio of the conductive particles is preferably 0.1% by volume to 20% by volume, and preferably 0.1% by volume to 2.% by volume based on the total volume of the adhesive. It is more preferably 5% by volume, and further preferably 0.1% by volume to 1.6% by volume.
  • a silane coupling agent, an aluminum coupling agent, a titanium coupling agent, a silicone pressure-sensitive adhesive, and an epoxy-modified silicone resin can be added to the adhesive from the viewpoint of adhesion.
  • a thickener, an antifoamer, a dispersing agent, etc. can be added to an adhesive agent as needed.
  • the content of other components is not particularly limited, but is preferably 20% by volume or less, more preferably 0.001% by volume to 20% by volume based on the total volume of the adhesive.
  • the conductive particles are conductive particles.
  • the Vickers hardness of the conductive particles is preferably 100 MPa to 600 MPa.
  • the Vickers hardness is a hardness calculated from a size traced by the diamond indenter by applying a weight to the material with the diamond indenter. From the viewpoint of preventing cracking of the substrate of the solar battery cell, the Vickers hardness of the conductive particles is preferably 600 MPa or less, more preferably 550 MPa or less, and further preferably 500 MPa or less.
  • the Vickers hardness is preferably 100 MPa or more, more preferably 200 MPa or more, and more preferably 300 MPa or more from the viewpoint of connection while eliminating the insulating resin component in the adhesive and obtaining good connection conductivity. More preferably, it is more preferably 400 MPa or more.
  • the Vickers hardness of the conductive particles can be measured by preparing a measurement sample having the same composition as the conductive particles and using a microhardness meter.
  • the conductive particles can be formed from a single component or a plurality of components.
  • the conductive particles preferably include at least one selected from, for example, copper, silver, gold, tin and the like.
  • Conductive particles formed from a plurality of components have appropriate hardness and softness, have both desired conductivity and desired Vickers hardness, and are alloyed to achieve appropriate conductivity and hardness. Can be adjusted, which is preferable. Therefore, the conductive particles are preferably an alloy composed of about 2 to 4 components.
  • the main component in the alloy composition of the conductive particles is preferably, for example, Cu—Ag, Cu—Au, Cu—Sn, Cu—Ag—Au, Ni—Au, and the like.
  • Cu—Ag, Ni—Au, Cu—Au and Cu—Sn are more preferable.
  • conductive particles of an alloy in which an additive component of about several percent by volume is added to conductive particles having these main components can also be used. Further, by mixing an appropriate amount of oxygen, the hardness of the conductive particles can be designed to a preferable value.
  • the oxygen concentration in the conductive particles is preferably 10 ppm or more, more preferably 200 ppm or more, and even more preferably 500 ppm or more. It is preferably 1000 ppm or more.
  • the oxygen concentration is preferably 10,000 ppm or less, more preferably 5000 ppm or less, and more preferably 3000 ppm or less from the viewpoint of preventing the hardness of the conductive particles from becoming excessively high and maintaining conductivity. More preferred is 2000 ppm or less.
  • the conductive particles preferably include particles having an average particle diameter of 1 ⁇ m to 30 ⁇ m.
  • a spherical shape, a substantially spherical shape, an indefinite shape, a fiber shape, a disk shape, or the like can be used.
  • the shape of the conductive particles is preferably spherical or substantially spherical.
  • the conductive particles can be produced using a method such as melting, chemical reduction, gas phase synthesis, or plating.
  • a particularly preferable method for producing conductive particles is a method in which a metal component is melted and solidified to an appropriate size.
  • a metal component containing one or more kinds selected from copper, silver, gold, aluminum and tin is once several hundred degrees or higher, preferably 500 ° C. or higher, more preferably 700 ° C. or higher, particularly preferably 900 ° C. or higher. Dissolve with to mix evenly.
  • a base material having such a composition that has been melt-mixed is rapidly solidified into a fine powder state by a known inert gas.
  • oxygen can be uniformly contained in the conductive alloy particles by containing a small amount of oxygen in the inert gas atmosphere. Also, water is sprayed on the dissolved base material to rapidly cool and solidify, so that oxygen is contained in the conductive powder, and then a reducing gas (for example, hydrogen gas) is sprayed, or in the reducing gas.
  • a reducing gas for example, hydrogen gas
  • a method of suitably controlling the oxygen concentration of the metal composition can be employed by leaving it to stand. By appropriately controlling the oxygen concentration, the Vickers hardness and conductivity of the conductive particles can be designed to a preferable level.
  • organic binder for example, at least selected from an epoxy resin, a polyimide resin, an acrylic resin, a phenoxy resin, a polyester resin, a urethane resin, a polyamide resin, a silicone resin, a modified resin, a thermosetting resin, and the like.
  • the organic binder is preferably one containing an epoxy resin and / or a silicone resin.
  • the curing agent can be added to the adhesive as a one-pack type, or can be added separately when the adhesive is cured as a two-pack type. Further, from the viewpoint of obtaining a reliable conductive connection, the organic binder more preferably contains a curing agent for curing the organic binder with heat. Therefore, the organic binder is more preferably a thermosetting resin. As the curing agent, an epoxy microcapsule type curing agent is particularly preferable from the viewpoint of achieving both reactivity and storage stability.
  • a known tab line can be used as the tab line.
  • the tab wire include a metal wire containing copper, silver, gold, tin, and the like.
  • a tab wire subjected to solder plating, tin plating, zinc plating or the like can be used as necessary.
  • the thickness of the tab line is 0.1 ⁇ m to 500 ⁇ m and the width of the tab line is 0.2 ⁇ m to 10 mm from the viewpoint of the handleability (handleability) of the tab line.
  • connection structure can be manufactured by connecting the surface electrode conductive wiring formed on the substrate of the solar battery cell and the tab wire with an adhesive containing conductive particles.
  • the adhesive the conductive particles and the organic binder are dispersed by adding an appropriate solvent, and the paste is used as it is in a paste state, or an inert film for the adhesive (for example, polyethylene terephthalate (PET). ), Polyethylene naphthalate (PEN), polyphenylene sulfide (PPS), polycarbonate (PC) film, etc.), a paste (for example, dispersion liquid) is applied, and the solvent is dried and scattered (volatilized) to form a film.
  • PET polyethylene terephthalate
  • PEN Polyethylene naphthalate
  • PPS polyphenylene sulfide
  • PC polycarbonate
  • the adhesive can be used as an adhesive (for example, an adhesive film).
  • the solvent include ethyl acetate and toluene.
  • a mixed solvent can also be used.
  • the thickness of the adhesive film is preferably 1 ⁇ m to 100 ⁇ m for handling, and the width of the adhesive film is preferably 0.5 mm to 50 mm for handling.
  • the adhesive paste or film is used by being applied or pasted onto the surface electrode conductive wiring of the solar battery cell, and is preferably cured by known heat, electron beam, light, cation, radical curing reaction or the like.
  • the curing rate of the adhesive is preferably in the range of 20% to 90%. From the viewpoint of giving the cured adhesive an appropriate flexibility and preventing cracking of the substrate of the solar battery cell, the curing rate of the adhesive is preferably 90% or less, more preferably 88% or less. Preferably, it is 85% or less. From the viewpoint of realizing reliable connection, the curing rate of the adhesive is preferably 20% or more, more preferably 30% or more, further preferably 40% or more, and 50% or more. Is particularly preferred. For example, in the case of a thermosetting binder, the curing rate of the adhesive can be adjusted by the heating temperature and the heating time.
  • heating the adhesive it is preferable to heat in the range of 0.1 second to 60 seconds from the viewpoint of productivity and connection conductivity.
  • a heating method for example, a heating body such as hot air, metal, ceramics or the like can be used.
  • the heating temperature of the adhesive is preferably a temperature at which the temperature of the adhesive itself is 100 ° C. to 400 ° C. from the viewpoint of preventing the substrate of the solar battery cell from being cracked by heating and obtaining good connection conductivity.
  • a temperature at which the temperature of the adhesive itself is 100 ° C. to 300 ° C. is more preferable, and a temperature at which the temperature of the adhesive itself is 100 ° C. to 200 ° C. is more preferable.
  • the warping direction of the connection body is convex on the light receiving portion side in order to obtain good solar cell performance by expanding the light receiving area.
  • the amount of warpage of the connection body is preferably 0.013 mm or more per 1 cm length between both ends of the tab line on the cell surface, more preferably from the viewpoint of obtaining good solar cell performance by expanding the light receiving area. 0.067 mm or more, more preferably 0.10 mm or more.
  • it is preferably 0.33 mm or less per 1 cm length between both ends of the tab line on the cell surface.
  • the length between both ends of the tab line on the cell surface means the length from one side of the tab line of the cell substrate to the other end side of the tab line in the direction in which the tab line is attached.
  • the amount of warpage of the solar battery cell can be measured as follows: After the adhesive is cured, the cell is placed on a smooth surface with the convex portion facing upward, and the maximum value of the distance from the smooth surface to the wiring having the copper component on the concave portion side is measured to obtain the magnitude of warpage.
  • the amount of warpage per 1 cm is calculated by measuring 10 times and dividing the average warpage size by the length between both ends of the tab line on the cell surface. The measurement can be performed in an environment of 50 ° C.
  • the amount of warpage of the solar battery cell can be adjusted by the curing rate of the cured adhesive and the elastic modulus (Young's modulus) at 50 ° C.
  • the preferable range of the curing rate is as described above, and can be appropriately adjusted according to the elastic modulus at 50 ° C. of the cured adhesive.
  • the elastic modulus at 50 ° C. of the cured adhesive is preferably from 0.1 to 6.0 GPa, more preferably from 0.3 to 5.0 GPa, even more preferably from the viewpoint of obtaining a preferred range of warpage. 1.0 to 4.0 GPa.
  • the elastic modulus at 50 ° C. of the cured adhesive is not the elastic modulus of the organic binder alone, but the elastic modulus of the entire adhesive including the conductive particles, and the influence of the component, size, and volume of the conductive particles has an effect. To do.
  • connection structure can be used for a solar cell or the like that exhibits good connection conductivity and does not crack even when the solar cell is thinned.
  • the physical properties of the conductive particles used were measured by the following methods.
  • the volume integrated average value was measured with a laser diffraction measuring instrument HEROS & RODOS SR type manufactured by Sympatec (Germany), and the particle diameter when the volume integrated value was 50% was defined as the average particle diameter value.
  • Oxygen concentration The oxygen concentration in the conductive particles was heated to 2000 ° C. and measured with EMGA650 (manufactured by Horiba, Ltd.).
  • Vickers hardness A sample for measurement having the same composition and the same oxygen concentration as the conductive particles was prepared.
  • the oxygen concentration of the measurement sample was prepared by high-temperature hydrogen reduction and air oxidation so as to be the same amount (within ⁇ 10%) as the conductive particles.
  • the oxygen concentration of the measurement sample was measured by the method (2) as with the conductive particles.
  • the Vickers hardness of the above measurement sample was measured with an HMV-1 microhardness meter manufactured by Shimadzu Corporation under conditions of a diamond Vickers indenter diagonal of 136 degrees and a test force of 0.098 to 9.8 N automatic switching.
  • the Vickers hardness is obtained by the following formula.
  • Vickers hardness HV (MPa) 0.1891 F / d 2
  • F Indenter weight (N)
  • d Diagonal length of traces on metal material by indenter (mm)
  • Table 1 shows the composition, average particle diameter, and Vickers hardness of the conductive particles used.
  • Curing rate (Heat generation amount of uncured adhesive cured to 250 ° C. ⁇ Heat generation amount cured to 250 ° C. by DSC after being immersed in silicone oil bath) / (Heat generation amount of uncured adhesive cured to 250 ° C.) ) X 100%
  • the amount of warpage of the solar battery cell After the adhesive is cured, the cell's convex part is placed on a smooth surface, and the maximum distance from the smooth surface to the wiring having the copper component on the concave side is measured. Say it. The measurement was performed 10 times, and the amount of warpage per 1 cm was calculated by dividing the average warpage size by the length to both ends of the tab line on the cell surface. The measurement was performed in an environment of 50 ° C.
  • Adhesive film is lightly pasted on a 20 ⁇ m thick surface electrode conductive wiring formed of silver paste on a silicon substrate having the thickness shown in Table 3 below, and the PET film is peeled off. After that, the tab wire is opposed to the surface electrode conductive wiring with the adhesive interposed therebetween, and the pressure of the adhesive shown in Table 3 is applied, and the temperature of the adhesive is set to the heating temperature shown in Table 3 for 16 seconds.
  • the tab wire was connected by pressurization and heating. After heating and pressurization, the pressurization location was observed with an optical microscope, and the degree of cracking of the substrate was evaluated according to the following criteria.
  • connection structures prepared in Examples 1 to 9 had sufficient connection conductivity and also had good substrate crack prevention properties.
  • connection structures prepared in Comparative Examples 1 to 3 had insufficient connection conductivity and / or had poor substrate cracking.
  • connection structure of the present invention can be used for a solar cell that exhibits good connection conductivity and does not crack even if it is a thinned solar cell.

Abstract

Provided is a method for manufacturing a connecting structure that includes a connecting step for connecting surface electrode conductive wiring of solar cells with a substrate thickness of 40 µm - 190 µm and tab wires by an adhesive that includes conductive particles that have a Vickers hardness of 100 MPa - 600 MPa.

Description

太陽電池セル接続構造体の製造方法Manufacturing method of solar cell connection structure
　本発明は、接続構造体、より詳細には、太陽電池セル、太陽電池モジュールなどとタブ線との接続構造体の製造方法に関する。 The present invention relates to a connection structure, and more particularly, to a method for manufacturing a connection structure between a solar battery cell, a solar battery module and the like and a tab wire.
　一般的に、太陽電池モジュールは、複数の太陽電池セルが、それらの表面電極と電気的に接続されたタブ線（配線部材）を介して、直列及び／又は並列に接続された構造を有している。この太陽電池モジュールを作製するときの、太陽電池セルの表面電極とタブ線との接続には、従来からはんだが用いられてきた。はんだは、導通性、固着強度等の接続信頼性に優れ、安価であり、かつ汎用性があるので、広く用いられている。 Generally, a solar cell module has a structure in which a plurality of solar cells are connected in series and / or in parallel via tab wires (wiring members) electrically connected to their surface electrodes. ing. Conventionally, solder has been used to connect the surface electrode of the solar battery cell and the tab wire when manufacturing this solar battery module. Solder is widely used because it is excellent in connection reliability such as conductivity and fixing strength, is inexpensive, and is versatile.
　しかしながら、はんだを接続に用いる場合には、はんだの溶解凝固による体積収縮及び熱収縮に起因して、太陽電池セルに反りが発生して、太陽電池セルの基板が割れてしまうことが多発している。この課題に対して、太陽電池における半導体構造の部材を加熱すること、及び／又ははんだ収縮を防ぐための導電性フィルムによる接続方法が開示されている（例えば、特許文献１及び２）。 However, when solder is used for connection, warpage of the solar cell due to volume shrinkage and thermal shrinkage due to dissolution and solidification of the solder often occurs, and the solar cell substrate is often cracked. Yes. With respect to this problem, a connection method using a conductive film for heating a member of a semiconductor structure in a solar cell and / or preventing solder shrinkage is disclosed (for example, Patent Documents 1 and 2).
　また、最近の太陽電池の低価格化に伴い、特にシリコン結晶系の太陽電池において、高価な基板を薄くしたいとする要求が高まりつつある。 Also, with the recent price reduction of solar cells, there is a growing demand for thin expensive substrates, particularly in silicon crystal solar cells.
　特許文献１に記述されている通りに導電性接着剤を用いる方法は、はんだを用いる方法と比べて低温での接続が可能となるため、薄型化された太陽電池セルの電気的な接続に適していると考えられる。一方で、特許文献２には、薄型化された太陽電池セルの接続方法が開示されている。 As described in Patent Document 1, the method using a conductive adhesive can be connected at a lower temperature than the method using a solder, and thus is suitable for electrical connection of thinned solar cells. It is thought that. On the other hand, Patent Document 2 discloses a method for connecting thin solar cells.
特開２００７－１５８３０２号公報JP 2007-158302 A 特開２０１１－０５４９４４号公報JP 2011-054944 A
　しかしながら、引用文献１及び２に記述されている方法を用いたとしても、接続導電性と割れの防止を両立することは困難であった。本発明は、かかる事情を鑑みてなされたものである。したがって、本発明は、薄型化された太陽電池セルであっても、良好な接続導電性を示し、かつ基板の割れが生じない接続構造体を提供することを目的とする。 However, even if the methods described in the cited documents 1 and 2 are used, it is difficult to achieve both connection conductivity and prevention of cracking. The present invention has been made in view of such circumstances. Accordingly, an object of the present invention is to provide a connection structure that exhibits good connection conductivity and does not cause cracking of a substrate even in a thinned solar battery cell.
　すなわち、本発明は下記の通りである。 That is, the present invention is as follows.
　［１］　基板の厚さが４０μｍ～１９０μｍである太陽電池セルの表面電極導電配線と、タブ線とを、ビッカース硬度が１００ＭＰａ～６００ＭＰａである導電粒子を含む接着剤により接続する接続工程を含む、接続構造体の製造方法。 [1] including a connection step of connecting the surface electrode conductive wiring of the solar battery cell having a substrate thickness of 40 μm to 190 μm and the tab wire with an adhesive containing conductive particles having a Vickers hardness of 100 MPa to 600 MPa. A manufacturing method of a connection structure.
　［２］　前記導電粒子の酸素含有量が、１０ｐｐｍ～１００００ｐｐｍである、［１］に記載の接続構造体の製造方法。 [2] The method for manufacturing a connection structure according to [1], wherein the conductive particles have an oxygen content of 10 ppm to 10,000 ppm.
　［３］　前記導電粒子が、銀又は銅成分を有する合金である、［１］又は［２］に記載の接続構造体の製造方法。 [3] The method for manufacturing a connection structure according to [1] or [2], wherein the conductive particles are an alloy having a silver or copper component.
　［４］　前記接着剤は、０．１体積％～２０体積％の導電粒子を含む、［１］～［３］のいずれか１項に記載の接続構造体の製造方法。 [4] The method for manufacturing a connection structure according to any one of [1] to [3], wherein the adhesive includes 0.1% by volume to 20% by volume of conductive particles.
　［５］　前記接着剤は、熱硬化性樹脂を含み、かつ前記接続工程において加圧及び加熱される、［１］～［４］のいずれか１項に記載の接続構造体の製造方法。 [5] The method for manufacturing a connection structure according to any one of [1] to [4], wherein the adhesive includes a thermosetting resin and is pressurized and heated in the connection step.
　［６］　［１］～［５］のいずれか１項に記載の製造方法によって製造された接続構造体を含む、太陽電池モジュール。 [6] A solar cell module including a connection structure manufactured by the manufacturing method according to any one of [1] to [5].
　［７］　太陽電池セルの表面電極導電配線、タブ線、及びそれらを電気的に接続している硬化した接着剤を含む接続構造体の製造方法であって、以下の工程：
　接着剤を硬化させることによって、接着剤の硬化率を２０％～９０％とする工程
を含む、前記接続構造体の製造方法。 [7] A method for producing a connection structure including a surface electrode conductive wiring of a solar battery cell, a tab wire, and a cured adhesive electrically connecting them, the following steps:
A method for producing the connection structure, comprising a step of setting the curing rate of the adhesive to 20% to 90% by curing the adhesive.
　［８］　前記接着剤が硬化した後の、前記太陽電池セルの受光部側が凸面であり、且つ５０℃における前記凸面の反りの大きさが、前記タブ線の両端までの長さ１ｃｍあたり０．０１３～０．３３ｍｍである、［７］に記載の接続構造体の製造方法。 [8] After the adhesive is cured, the light receiving part side of the solar battery cell is a convex surface, and the warpage of the convex surface at 50 ° C. is 0. 1 cm per length to the both ends of the tab wire. The method for producing a connection structure according to [7], which is 013 to 0.33 mm.
　［９］　前記硬化した接着剤の弾性率が、０．１～６．０ＧＰａである、［７］又は［８］に記載の接続構造体の製造方法。 [9] The method for manufacturing a connection structure according to [7] or [8], wherein the elastic modulus of the cured adhesive is 0.1 to 6.0 GPa.
　［１０］　前記太陽電池セルの基板の厚さが４０μｍ～１９０μｍである、［７］～［９］のいずれか１項に記載の接続構造体の製造方法。 [10] The method for manufacturing a connection structure according to any one of [7] to [9], wherein the solar cell substrate has a thickness of 40 μm to 190 μm.
　本発明により、薄い基板を用いた太陽電池セルと配線部材との接続時に、良好な接続導電性を示し、かつ基板の割れが生じない接続構造体を提供することができる。 According to the present invention, it is possible to provide a connection structure that exhibits good connection conductivity and does not cause cracking of the substrate when the solar cell using a thin substrate and the wiring member are connected.
　以下、本発明を実施するための形態（以下、「実施の形態」と略記する）について詳細に説明する。尚、本発明は、以下の実施の形態に限定されるものではなく、種々変形して実施することができる。 Hereinafter, modes for carrying out the present invention (hereinafter abbreviated as “embodiments”) will be described in detail. The present invention is not limited to the following embodiments, and can be implemented with various modifications.
　本実施の形態では、基板の厚さが４０μｍ～１９０μｍである太陽電池セルの表面電極導電配線と、タブ線とを、ビッカース硬度が１００ＭＰａ～６００ＭＰａである導電粒子を含む接着剤により接続する接続工程を含む、接続構造体の製造方法を提供する。 In the present embodiment, the connection step of connecting the surface electrode conductive wiring of the solar battery cell having a substrate thickness of 40 μm to 190 μm and the tab wire with an adhesive containing conductive particles having a Vickers hardness of 100 MPa to 600 MPa. A method for manufacturing a connection structure is provided.
　また、太陽電池セルの表面電極導電配線、タブ線、及びそれらを電気的に接続している硬化した接着剤を含む接続構造体の製造方法であって、接着剤を硬化させることによって、接着剤の硬化率を２０％～９０％とする工程を含む、前記接続構造体の製造方法も提供される。 Moreover, it is a manufacturing method of the connection structure containing the surface electrode conductive wiring of a photovoltaic cell, a tab line, and the hardened adhesive which has electrically connected them, Comprising: By hardening an adhesive, an adhesive There is also provided a method for producing the connection structure, which includes a step of setting the curing rate of 20% to 90%.
（太陽電池セル基板）
　本実施の形態における太陽電池セルは、基板及び表面電極導電配線を有する。基板の厚さは、４０μｍ～１９０μｍが好ましく、より好ましくは５０μｍ～１８０μｍ、さらに好ましくは６０μｍ～１７５μｍである。基板の厚さが１９０μｍ以下であると、接続構造体の性能及びコストの観点で好ましい。一方で、基板の厚さが４０μｍ以上であると、太陽光の利用効率の観点で好ましい。 (Solar cell substrate)
The solar battery cell in the present embodiment has a substrate and a surface electrode conductive wiring. The thickness of the substrate is preferably 40 μm to 190 μm, more preferably 50 μm to 180 μm, and still more preferably 60 μm to 175 μm. A thickness of the substrate of 190 μm or less is preferable from the viewpoint of performance and cost of the connection structure. On the other hand, when the thickness of the substrate is 40 μm or more, it is preferable from the viewpoint of utilization efficiency of sunlight.
　基板としては、例えば、多結晶、単結晶及びアモルファスのシリコン基板、ＩｎＧａＡｓ基板、ＧａＡｓ基板、ＣＩＧＳ基板などが挙げられる。また、基板の製造方法としては、例えば、溶融、気相法などが挙げられる。また、必要に応じて、基板の表面を粗くする、反射防止膜を付ける、表面賦形処理をする等の処理をすることができる。
　また、基板には、ｐｎ接合部を作製するために少量の添加物がドープされることができる。 Examples of the substrate include polycrystalline, single crystal, and amorphous silicon substrates, InGaAs substrates, GaAs substrates, CIGS substrates, and the like. Moreover, as a manufacturing method of a board | substrate, a melting | fusing, vapor phase method etc. are mentioned, for example. Further, if necessary, the surface of the substrate can be roughened, an antireflection film can be applied, or a surface shaping process can be performed.
Also, the substrate can be doped with a small amount of additive to make a pn junction.
（表面電極導電配線）
　本実施の形態の太陽電池セルは、基板上に表面電極として導電配線を有する。接続構造体のサイズを適切に調整するために、表面電極導電配線の幅は、０．２μｍ～２ｍｍであることが好ましく、１０μｍ～１ｍｍであることがより好ましい。 (Surface electrode conductive wiring)
The solar battery cell of this embodiment has a conductive wiring as a surface electrode on a substrate. In order to appropriately adjust the size of the connection structure, the width of the surface electrode conductive wiring is preferably 0.2 μm to 2 mm, and more preferably 10 μm to 1 mm.
　また、導電配線は、基板の表面から裏側にホール又は側面を通して、形成することも可能である。 Also, the conductive wiring can be formed through holes or side surfaces from the front surface to the back surface of the substrate.
　熱によるストレスを小さくする観点から、表面電極導電配線の厚さは、０．１μｍ～５０μｍであることが好ましく、０．１μｍ～３０μｍであることがより好ましい。 From the viewpoint of reducing heat stress, the thickness of the surface electrode conductive wiring is preferably 0.1 μm to 50 μm, and more preferably 0.1 μm to 30 μm.
　また、適切な導通を可能にする観点から、導電配線は、銀、金、銅及びアルミニウムから成る群から選択される少なくとも１つを含むことが好ましい。さらに、導電配線と導電粒子との導電的接合において、導電配線及び／又は導電粒子を形成する成分の拡散を抑制して、安定な接続を得る観点から、導電粒子と導電配線との成分は、同一であるか、又は互いに近似していることがより好ましい。 Also, from the viewpoint of enabling appropriate conduction, the conductive wiring preferably includes at least one selected from the group consisting of silver, gold, copper, and aluminum. Furthermore, in the conductive bonding between the conductive wiring and the conductive particles, from the viewpoint of obtaining a stable connection by suppressing diffusion of the components forming the conductive wiring and / or conductive particles, the components of the conductive particles and the conductive wiring are: More preferably, they are identical or close to each other.
（接着剤）
　本実施の形態では、接続構造体を形成する接着剤は、導電粒子及び有機バインダーを含む。導電粒子の含有比率は、より良好な接続導電性を得る観点から、接着剤の全体積を基準として、０．１体積％～２０体積％であることが好ましく、０．１体積％～２．５体積％であることがより好ましく、０．１体積％～１．６体積％であることがさらに好ましい。 (adhesive)
In the present embodiment, the adhesive forming the connection structure includes conductive particles and an organic binder. From the viewpoint of obtaining better connection conductivity, the content ratio of the conductive particles is preferably 0.1% by volume to 20% by volume, and preferably 0.1% by volume to 2.% by volume based on the total volume of the adhesive. It is more preferably 5% by volume, and further preferably 0.1% by volume to 1.6% by volume.
　また、その他の成分として、密着性の観点から、例えば、シランカップリング剤、アルミカップリング剤、チタンカップリング剤、シリコーン粘着剤、エポキシ変性シリコーン樹脂などが接着剤に加えられることができる。また、必要に応じて、増粘剤、消泡剤、分散剤などが接着剤に加えられることができる。その他の成分の含有量は、特に制限されないが、接着剤の全体積を基準として、２０体積％以下であることが好ましく、０．００１体積％～２０体積％であることがより好ましい。 As other components, for example, a silane coupling agent, an aluminum coupling agent, a titanium coupling agent, a silicone pressure-sensitive adhesive, and an epoxy-modified silicone resin can be added to the adhesive from the viewpoint of adhesion. Moreover, a thickener, an antifoamer, a dispersing agent, etc. can be added to an adhesive agent as needed. The content of other components is not particularly limited, but is preferably 20% by volume or less, more preferably 0.001% by volume to 20% by volume based on the total volume of the adhesive.
（導電粒子）
　本実施の形態では、導電粒子は、導電性を有する粒子である。導電粒子のビッカース硬度は、１００ＭＰａ～６００ＭＰａであることが好ましい。ビッカース硬度は、ダイヤモンド圧子により、材料に加重を掛けていき、ダイヤモンド圧子により痕跡される大きさから、算出される硬度である。太陽電池セルの基板の割れを防止する観点から、導電粒子のビッカース硬度は６００ＭＰａ以下であることが好ましく、５５０ＭＰａ以下であることがより好ましく、５００ＭＰａ以下であることがさらに好ましい。一方で、接着剤中の絶縁樹脂成分を排除しながら接続し、かつ良好な接続導電性を得る観点から、ビッカース硬度は１００ＭＰａ以上であることが好ましく、２００ＭＰａ以上であることがより好ましく、３００ＭＰａ以上であることがさらに好ましく、４００ＭＰａ以上であることが特に好ましい。
　導電粒子のビッカース硬度は、導電粒子と同一組成の測定用サンプルを作製して、微小硬度計を用いて測定することができる。 (Conductive particles)
In the present embodiment, the conductive particles are conductive particles. The Vickers hardness of the conductive particles is preferably 100 MPa to 600 MPa. The Vickers hardness is a hardness calculated from a size traced by the diamond indenter by applying a weight to the material with the diamond indenter. From the viewpoint of preventing cracking of the substrate of the solar battery cell, the Vickers hardness of the conductive particles is preferably 600 MPa or less, more preferably 550 MPa or less, and further preferably 500 MPa or less. On the other hand, the Vickers hardness is preferably 100 MPa or more, more preferably 200 MPa or more, and more preferably 300 MPa or more from the viewpoint of connection while eliminating the insulating resin component in the adhesive and obtaining good connection conductivity. More preferably, it is more preferably 400 MPa or more.
The Vickers hardness of the conductive particles can be measured by preparing a measurement sample having the same composition as the conductive particles and using a microhardness meter.
　導電粒子は、単独成分又は複数の成分から形成されることができる。導電粒子は、例えば、銅、銀、金、スズなどから選ばれる少なくとも１つを含むことが好ましい。また、複数の成分から形成される導電粒子は、適度な硬さ及び軟らかさを有し、所望の導電性と所望のビッカース硬度を両立し、かつ合金化されることにより適度な導電性と硬度を調整することができるので好ましい。したがって、導電粒子は、２～４成分程度から成る合金であることが好ましい。 The conductive particles can be formed from a single component or a plurality of components. The conductive particles preferably include at least one selected from, for example, copper, silver, gold, tin and the like. Conductive particles formed from a plurality of components have appropriate hardness and softness, have both desired conductivity and desired Vickers hardness, and are alloyed to achieve appropriate conductivity and hardness. Can be adjusted, which is preferable. Therefore, the conductive particles are preferably an alloy composed of about 2 to 4 components.
　具体的には、導電粒子の合金組成における主成分としては、例えば、Ｃｕ－Ａｇ系、Ｃｕ－Ａｕ系、Ｃｕ－Ｓｎ系、Ｃｕ－Ａｇ－Ａｕ系、Ｎｉ－Ａｕ系などが好ましく、その中でもＣｕ－Ａｇ系、Ｎｉ－Ａｕ系、Ｃｕ－Ａｕ系及びＣｕ－Ｓｎ系がより好ましい。また、これらの主成分を有する導電粒子に数体積％程度の添加成分を加えた合金の導電粒子を用いることもできる。
　また、酸素を適量混合させることで、さらに、導電粒子の硬度を好ましい値に設計することができる。導電粒子に硬さを付与し、適度なビッカース硬度に調整する観点から、導電粒子中の酸素濃度は１０ｐｐｍ以上であることが好ましく、２００ｐｐｍ以上であることがより好ましく、５００ｐｐｍ以上であることがさらに好ましく、１０００ｐｐｍ以上であることが特に好ましい。一方で、導電粒子の硬度が過度に高くならないようにし、かつ導電性を維持する観点から、酸素濃度が１００００ｐｐｍ以下であることが好ましく、５０００ｐｐｍ以下であることがより好ましく、３０００ｐｐｍ以下であることがさらに好ましく、２０００ｐｐｍ以下であることが特に好ましい。 Specifically, the main component in the alloy composition of the conductive particles is preferably, for example, Cu—Ag, Cu—Au, Cu—Sn, Cu—Ag—Au, Ni—Au, and the like. Cu—Ag, Ni—Au, Cu—Au and Cu—Sn are more preferable. In addition, conductive particles of an alloy in which an additive component of about several percent by volume is added to conductive particles having these main components can also be used.
Further, by mixing an appropriate amount of oxygen, the hardness of the conductive particles can be designed to a preferable value. From the viewpoint of imparting hardness to the conductive particles and adjusting to an appropriate Vickers hardness, the oxygen concentration in the conductive particles is preferably 10 ppm or more, more preferably 200 ppm or more, and even more preferably 500 ppm or more. It is preferably 1000 ppm or more. On the other hand, the oxygen concentration is preferably 10,000 ppm or less, more preferably 5000 ppm or less, and more preferably 3000 ppm or less from the viewpoint of preventing the hardness of the conductive particles from becoming excessively high and maintaining conductivity. More preferred is 2000 ppm or less.
　導電粒子が接着剤に含まれるときの作業性を向上させる観点から、導電粒子は、１μｍ～３０μｍの平均粒子径を有する粒子を含むことが好ましい。
　導電粒子の形状は、球状、略球状、不定形、繊維状、円板状などを用いることができる。導電粒子が接着剤に含まれるときの作業性を向上させる観点から、導電粒子の形状は、球状又は略球状であることが好ましい。 From the viewpoint of improving workability when the conductive particles are contained in the adhesive, the conductive particles preferably include particles having an average particle diameter of 1 μm to 30 μm.
As the shape of the conductive particles, a spherical shape, a substantially spherical shape, an indefinite shape, a fiber shape, a disk shape, or the like can be used. From the viewpoint of improving workability when the conductive particles are contained in the adhesive, the shape of the conductive particles is preferably spherical or substantially spherical.
　本実施の形態では、導電粒子は、例えば、溶融、化学還元、気相合成、メッキなどの方法を用いて作製されることができる。
　特に好ましい導電粒子の製造方法は、金属成分を溶融させて、適度な大きさに凝固させる方法である。
　具体的には、銅、銀、金、アルミ、すずから選ばれた１種類以上を含む金属成分を一度数百度以上、好ましくは５００℃以上、さらに好ましくは７００℃以上、特に好ましくは９００℃以上で溶解して均一になるように混合する。一般的には、溶融混合されたかかる組成の母材を、既知の不活性ガスにより微粉状態へ急冷凝固させる。溶解された母材を導電性合金粒子へ凝固させるときに、不活性ガス雰囲気中に酸素を少量含有させることで、導電性合金粒子に均一に酸素を含有させることができる。
　また、溶解された母材に水を吹付けて急冷凝固させることで、酸素を導電粉末に含有させ、その後に還元性ガス（例えば、水素ガスなど）を吹付けるか、又は還元性ガス中に放置することで、金属組成の酸素濃度を好適に制御する方法も採用することができる。
　酸素濃度を適度に制御することで、導電粒子のビッカース硬度、及び導電性を好ましいレベルに設計することができる。 In the present embodiment, the conductive particles can be produced using a method such as melting, chemical reduction, gas phase synthesis, or plating.
A particularly preferable method for producing conductive particles is a method in which a metal component is melted and solidified to an appropriate size.
Specifically, a metal component containing one or more kinds selected from copper, silver, gold, aluminum and tin is once several hundred degrees or higher, preferably 500 ° C. or higher, more preferably 700 ° C. or higher, particularly preferably 900 ° C. or higher. Dissolve with to mix evenly. In general, a base material having such a composition that has been melt-mixed is rapidly solidified into a fine powder state by a known inert gas. When solidifying the dissolved base material into conductive alloy particles, oxygen can be uniformly contained in the conductive alloy particles by containing a small amount of oxygen in the inert gas atmosphere.
Also, water is sprayed on the dissolved base material to rapidly cool and solidify, so that oxygen is contained in the conductive powder, and then a reducing gas (for example, hydrogen gas) is sprayed, or in the reducing gas. A method of suitably controlling the oxygen concentration of the metal composition can be employed by leaving it to stand.
By appropriately controlling the oxygen concentration, the Vickers hardness and conductivity of the conductive particles can be designed to a preferable level.
（有機バインダー）
　本実施の形態において、有機バインダーとしては、例えば、エポキシ樹脂、ポリイミド樹脂、アクリル樹脂、フェノキシ樹脂、ポリエステル樹脂、ウレタン樹脂、ポリアミド樹脂、シリコーン樹脂、変性樹脂、熱硬化性樹脂などから選ばれた少なくとも１種類が挙げられる。これらは、１種類を単独で又は２種類以上を組み合わせて使用されることができる。特に、有機バインダーとしては、エポキシ樹脂及び／又はシリコーン樹脂を含むものが好ましい。また、熱、紫外線、電子線などで有機バインダーを硬化するために、有機バインダーに硬化剤を加えることが好ましい。硬化剤は、一液型として接着剤に加えておくか、又は二液型として接着剤の硬化時に別途加えることができる。
　また、確実な導電接続を得るという観点から、有機バインダーは、熱により有機バインダーを硬化するための硬化剤を含むことがより好ましい。したがって、有機バインダーは熱硬化性樹脂であることがより好ましい。硬化剤としては、特にエポキシ系のマイクロカプセル型の硬化剤が、反応性と保存性を両立させるという観点で好ましい。 (Organic binder)
In the present embodiment, as the organic binder, for example, at least selected from an epoxy resin, a polyimide resin, an acrylic resin, a phenoxy resin, a polyester resin, a urethane resin, a polyamide resin, a silicone resin, a modified resin, a thermosetting resin, and the like. One type is mentioned. These can be used singly or in combination of two or more. In particular, the organic binder is preferably one containing an epoxy resin and / or a silicone resin. Moreover, it is preferable to add a curing agent to the organic binder in order to cure the organic binder with heat, ultraviolet rays, electron beams or the like. The curing agent can be added to the adhesive as a one-pack type, or can be added separately when the adhesive is cured as a two-pack type.
Further, from the viewpoint of obtaining a reliable conductive connection, the organic binder more preferably contains a curing agent for curing the organic binder with heat. Therefore, the organic binder is more preferably a thermosetting resin. As the curing agent, an epoxy microcapsule type curing agent is particularly preferable from the viewpoint of achieving both reactivity and storage stability.
（タブ線）
　本実施の形態では、タブ線としては、既知のタブ線を用いることができる。例えば、タブ線としては、銅、銀、金、スズなどを含む金属線が挙げられる。また、必要に応じて、例えば、はんだメッキ、スズメッキ、亜鉛メッキなどを施したタブ線が使用されることができる。 (Tab line)
In the present embodiment, a known tab line can be used as the tab line. For example, examples of the tab wire include a metal wire containing copper, silver, gold, tin, and the like. Further, for example, a tab wire subjected to solder plating, tin plating, zinc plating or the like can be used as necessary.
　本実施の形態では、タブ線の取り扱い性（ハンドリング性）の観点から、タブ線の厚さは０．１μｍ～５００μｍであり、タブ線の幅は０．２μｍ～１０ｍｍであることが好ましい。 In the present embodiment, it is preferable that the thickness of the tab line is 0.1 μm to 500 μm and the width of the tab line is 0.2 μm to 10 mm from the viewpoint of the handleability (handleability) of the tab line.
（接続構造体の製造方法）
　本実施の形態では、接続構造体は、太陽電池セルの基板に形成された表面電極導電配線と、タブ線とを、導電粒子を含む接着剤により接続することにより製造されることができる。また、接着剤は、導電粒子と有機バインダーとを適当な溶剤を加えて分散させ、そのペースト状態のままで使用するか、又は接着剤に対しては不活性なフィルム（例えば、ポリエチレンテレフタレート（ＰＥＴ）、ポリエチレンナフタレート（ＰＥＮ）、ポリフェニレンスルフィド（ＰＰＳ）、ポリカーボネート（ＰＣ）などのフィルム）にペースト（例えば、分散液など）を塗布して、溶剤を乾燥及び飛散（揮発）させてフィルム状の接着剤（例えば、接着剤フィルムなど）として使用することができる。溶剤としては、例えば、酢酸エチル、トルエンなどが挙げられる。また、混合溶媒を用いることもできる。
　接着剤をフィルムとして用いる場合には、接着剤フィルムの厚さは、１μｍ～１００μｍであることが取り扱い上好ましく、接着剤フィルムの幅は０．５ｍｍ～５０ｍｍであることが取り扱い上好ましい。 (Method for manufacturing connection structure)
In the present embodiment, the connection structure can be manufactured by connecting the surface electrode conductive wiring formed on the substrate of the solar battery cell and the tab wire with an adhesive containing conductive particles. In addition, as for the adhesive, the conductive particles and the organic binder are dispersed by adding an appropriate solvent, and the paste is used as it is in a paste state, or an inert film for the adhesive (for example, polyethylene terephthalate (PET). ), Polyethylene naphthalate (PEN), polyphenylene sulfide (PPS), polycarbonate (PC) film, etc.), a paste (for example, dispersion liquid) is applied, and the solvent is dried and scattered (volatilized) to form a film. It can be used as an adhesive (for example, an adhesive film). Examples of the solvent include ethyl acetate and toluene. Moreover, a mixed solvent can also be used.
When the adhesive is used as a film, the thickness of the adhesive film is preferably 1 μm to 100 μm for handling, and the width of the adhesive film is preferably 0.5 mm to 50 mm for handling.
　接着剤ペースト又はフィルムは、太陽電池セルの表面電極導電配線上に塗布又は貼付して用いられるが、既知の熱、電子線、光、カチオン、ラジカル硬化反応などにより硬化されることが好ましい。
　接着剤の硬化率は２０％～９０％の範囲であることが好ましい。硬化後の接着剤に適度な柔軟性を持たせ、太陽電池セルの基板の割れを防止する観点から、接着剤の硬化率は９０％以下であることが好ましく、８８％以下であることがより好ましく、８５％以下であることがさらに好ましい。確実な接続を実現する観点から、接着剤の硬化率は２０％以上であることが好ましく、３０％以上であることがより好ましく、４０％以上であることがさらに好ましく、５０％以上であることが特に好ましい。
　接着剤の硬化率は、例えば熱硬化性のバインダーでは、加熱温度及び加熱時間により調整することができる。 The adhesive paste or film is used by being applied or pasted onto the surface electrode conductive wiring of the solar battery cell, and is preferably cured by known heat, electron beam, light, cation, radical curing reaction or the like.
The curing rate of the adhesive is preferably in the range of 20% to 90%. From the viewpoint of giving the cured adhesive an appropriate flexibility and preventing cracking of the substrate of the solar battery cell, the curing rate of the adhesive is preferably 90% or less, more preferably 88% or less. Preferably, it is 85% or less. From the viewpoint of realizing reliable connection, the curing rate of the adhesive is preferably 20% or more, more preferably 30% or more, further preferably 40% or more, and 50% or more. Is particularly preferred.
For example, in the case of a thermosetting binder, the curing rate of the adhesive can be adjusted by the heating temperature and the heating time.
　また、確実な導電接続を得る観点から、必要に応じて、接着剤に含まれる有機バインダーを硬化するときに、同時に加圧することが好ましい。例えば、接着剤の加圧及び加熱部の接触面積当たり、０．２ＭＰａ～５ＭＰａの加圧を行うことが好ましい。 In addition, from the viewpoint of obtaining a reliable conductive connection, it is preferable to apply pressure simultaneously when curing the organic binder contained in the adhesive, if necessary. For example, it is preferable to apply pressure of 0.2 MPa to 5 MPa per pressure of the adhesive and the contact area of the heating part.
　接着剤を加熱する場合には、生産性及び接続導電性の観点から、０．１秒～６０秒の範囲で加熱を行うことが好ましい。加熱方法としては、例えば、熱風、金属、セラミックスなどの加熱体を用いることができる。 When heating the adhesive, it is preferable to heat in the range of 0.1 second to 60 seconds from the viewpoint of productivity and connection conductivity. As a heating method, for example, a heating body such as hot air, metal, ceramics or the like can be used.
　接着剤の加熱温度としては、太陽電池セルの基板が加熱により割れることの防止、及び良好な接続導電性を得る観点から、接着剤自体の温度が１００℃～４００℃となるような温度が好ましく、接着剤自体の温度が１００℃～３００℃となるような温度がより好ましく、接着剤自体の温度が１００℃～２００℃となるような温度がさらに好ましい。 The heating temperature of the adhesive is preferably a temperature at which the temperature of the adhesive itself is 100 ° C. to 400 ° C. from the viewpoint of preventing the substrate of the solar battery cell from being cracked by heating and obtaining good connection conductivity. A temperature at which the temperature of the adhesive itself is 100 ° C. to 300 ° C. is more preferable, and a temperature at which the temperature of the adhesive itself is 100 ° C. to 200 ° C. is more preferable.
　さらに、接続体に反りが発生するときには、接続体の反りの方向は、受光面積の拡大により良好な太陽電池性能を得るため、受光部側が凸面になることが好ましい。また、接続体の反り量は、受光面積の拡大により良好な太陽電池性能を得る観点から、セル面上のタブ線両端間の長さ１ｃｍあたり０．０１３ｍｍ以上であることが好ましく、より好ましくは０．０６７ｍｍ以上、さらに好ましくは０．１０ｍｍ以上であり、一方で、セル基板の割れを防止する観点から、セル面上のタブ線両端間の長さ１ｃｍあたり０．３３ｍｍ以下であることが好ましく、より好ましくは０．２０ｍｍ以下、さらに好ましくは０．１５ｍｍ以下である。なお、セル面上のタブ線両端間の長さとは、セル基板のタブ線片側から、タブ線が付いている方向に向かってタブ線のもう一端側までの長さをいう。理論に拘束されるものではないが、太陽電池は、屋外で使用されることが多いので、太陽光が当たると直ぐにセルが約５０℃に曝される状態になる。そのため、通常の電気製品と異なり、約５０℃が通常の太陽電池セルの常用温度になる。そのため、本明細書では、５０℃における反りの大きさを規定している。 Furthermore, when warping occurs in the connection body, it is preferable that the warping direction of the connection body is convex on the light receiving portion side in order to obtain good solar cell performance by expanding the light receiving area. Further, the amount of warpage of the connection body is preferably 0.013 mm or more per 1 cm length between both ends of the tab line on the cell surface, more preferably from the viewpoint of obtaining good solar cell performance by expanding the light receiving area. 0.067 mm or more, more preferably 0.10 mm or more. On the other hand, from the viewpoint of preventing cracking of the cell substrate, it is preferably 0.33 mm or less per 1 cm length between both ends of the tab line on the cell surface. More preferably, it is 0.20 mm or less, More preferably, it is 0.15 mm or less. The length between both ends of the tab line on the cell surface means the length from one side of the tab line of the cell substrate to the other end side of the tab line in the direction in which the tab line is attached. Without being bound by theory, solar cells are often used outdoors, so that the cells are immediately exposed to about 50 ° C. when exposed to sunlight. Therefore, unlike a normal electric product, about 50 ° C. is the normal temperature of a normal solar battery cell. Therefore, in this specification, the magnitude | size of the curvature in 50 degreeC is prescribed | regulated.
　また、太陽電池セルの反り量の測定は下記のように行なうことができる：
　接着剤の硬化後にセルの凸部を上にして平滑面状に設置し、平滑面から凹部側の銅成分を有する配線までの距離の最大値を測定し、反りの大きさとする。１０回測定し、その平均の反りの大きさを、セル面上のタブ線両端間の長さで割ることで、１ｃｍあたりの反り量を算出する。測定は５０℃の環境下にて実施することができる。 Further, the amount of warpage of the solar battery cell can be measured as follows:
After the adhesive is cured, the cell is placed on a smooth surface with the convex portion facing upward, and the maximum value of the distance from the smooth surface to the wiring having the copper component on the concave portion side is measured to obtain the magnitude of warpage. The amount of warpage per 1 cm is calculated by measuring 10 times and dividing the average warpage size by the length between both ends of the tab line on the cell surface. The measurement can be performed in an environment of 50 ° C.
　太陽電池セルの反り量は、硬化した接着剤の硬化率、及び５０℃における弾性率（ヤング率）によって調整することができる。
　硬化率の好ましい範囲は、先述の通りであり、硬化した接着剤の５０℃における弾性率に合わせ、適宜調整することができる。
　硬化した接着剤の５０℃における弾性率は、好ましい範囲の反りを得る観点から０．１～６．０ＧＰａであることが好ましく、０．３～５．０ＧＰａであることがより好ましく、さらに好ましくは、１．０～４．０ＧＰａである。この範囲であれば、太陽電池セルの他の層に対応させて、反りの大きさを適切な範囲に制御することができ、それによって割れを低減することができる。ここで、硬化した接着剤の５０℃における弾性率は、有機バインダー単体の弾性率でなく、導電粒子を含んだ接着剤全体の弾性率を指し、導電粒子の成分、大きさ、体積量が影響するものである。 The amount of warpage of the solar battery cell can be adjusted by the curing rate of the cured adhesive and the elastic modulus (Young's modulus) at 50 ° C.
The preferable range of the curing rate is as described above, and can be appropriately adjusted according to the elastic modulus at 50 ° C. of the cured adhesive.
The elastic modulus at 50 ° C. of the cured adhesive is preferably from 0.1 to 6.0 GPa, more preferably from 0.3 to 5.0 GPa, even more preferably from the viewpoint of obtaining a preferred range of warpage. 1.0 to 4.0 GPa. If it is this range, it can be made to respond | correspond to the other layer of a photovoltaic cell, the magnitude | size of curvature can be controlled to an appropriate range, and it can reduce a crack by it. Here, the elastic modulus at 50 ° C. of the cured adhesive is not the elastic modulus of the organic binder alone, but the elastic modulus of the entire adhesive including the conductive particles, and the influence of the component, size, and volume of the conductive particles has an effect. To do.
　本実施の形態では、接続構造体は、薄型化された太陽電池セルであっても、良好な接続導電性を示し、かつ割れも生じない太陽電池などに使用されることができる。 In the present embodiment, the connection structure can be used for a solar cell or the like that exhibits good connection conductivity and does not crack even when the solar cell is thinned.
　以下に実施例及び比較例を挙げて本実施の形態をより具体的に説明するが、本発明は以下の実施例に限定されるものではない。 Hereinafter, the present embodiment will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples.
　使用した導電粒子の物性を下記に示す方法で測定した。 The physical properties of the conductive particles used were measured by the following methods.
（１）平均粒子径
　Ｓｙｍｐａｔｅｃ社（ドイツ）製レーザー回折型測定器ＨＥＲＯＳ＆ＲＯＤＯＳ　ＳＲ型により体積積算平均値を測定し、体積積算５０％になるときの粒子径を平均粒子径値とした。 (1) Average particle diameter The volume integrated average value was measured with a laser diffraction measuring instrument HEROS & RODOS SR type manufactured by Sympatec (Germany), and the particle diameter when the volume integrated value was 50% was defined as the average particle diameter value.
（２）酸素濃度
　導電粒子中の酸素濃度は、２０００℃に加熱し、ＥＭＧＡ６５０（堀場製作所製）により測定した。 (2) Oxygen concentration The oxygen concentration in the conductive particles was heated to 2000 ° C. and measured with EMGA650 (manufactured by Horiba, Ltd.).
（３）ビッカース硬度
　導電粒子と同組成、同一酸素濃度の測定用サンプルを作製した。測定用サンプルの酸素濃度は、導電粒子と同量（±１０％以内）になるように高温水素還元と空気酸化により調製した。測定用サンプルの酸素濃度は、導電粒子と同様に、上記（２）の方法で測定した。
　上記測定用サンプルのビッカース硬度を、島津製作所社製ＨＭＶ－１微小硬度計によりダイヤモンドビッカース圧子対角１３６度、試験力０．０９８～９．８Ｎ自動切換の条件にて測定した。ビッカース硬度は下記式により得られる。
　　ビッカース硬度　ＨＶ（ＭＰａ）＝０．１８９１Ｆ／ｄ２
　　　Ｆ：圧子加重（Ｎ）
　　　ｄ：圧子により金属材に付いた痕跡の対角線長さ（ｍｍ） (3) Vickers hardness A sample for measurement having the same composition and the same oxygen concentration as the conductive particles was prepared. The oxygen concentration of the measurement sample was prepared by high-temperature hydrogen reduction and air oxidation so as to be the same amount (within ± 10%) as the conductive particles. The oxygen concentration of the measurement sample was measured by the method (2) as with the conductive particles.
The Vickers hardness of the above measurement sample was measured with an HMV-1 microhardness meter manufactured by Shimadzu Corporation under conditions of a diamond Vickers indenter diagonal of 136 degrees and a test force of 0.098 to 9.8 N automatic switching. The Vickers hardness is obtained by the following formula.
Vickers hardness HV (MPa) = 0.1891 F / d 2
F: Indenter weight (N)
d: Diagonal length of traces on metal material by indenter (mm)
　使用した導電粒子の組成、平均粒子径及びビッカース硬度を表１に示す。 Table 1 shows the composition, average particle diameter, and Vickers hardness of the conductive particles used.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　＜実施例１～９＞、＜比較例１～３＞
　下記表２に示される組成１～１０を有する接着剤組成物のそれぞれを、５０質量％の濃度で酢酸エチル溶剤に溶解し、５０μｍの厚みを有するＰＥＴ上に塗布し、空気中において６０℃で１０分間に亘って乾燥して、酢酸エチル溶剤を揮発させ、厚さ２５μｍの接着剤フィルムを作製した。
　導電粒子の体積％は、接着剤（導電粒子＋有機バインダー）全体中に導電粒子が占める体積％を示す。有機バインダーの各成分の体積％は、導電粒子を含まない有機バインダー中の各成分の体積％とする。
　表２において、接着剤中の有機バインダーの各成分には、下記のものを用いた：
ａ．ビスフェノールＡ型エポキシ樹脂（旭化成ケミカルズ社製ＡＥＲ２６００）
ｂ．ジシクロペンタジエン型エポキシ樹脂（大日本インキ社製ＨＰ７２００）
ｃ．ビスフェノールＡ型フェノキシ樹脂（ＩｎＣｈｅｍ　Ｃｏｒｐｏｒａｔｉｏｎ社（米国、サウスカロライナ州、ロックヒル）製ＰＫＨＣ）
ｄ．潜在性硬化剤（旭化成エポキシ社製ＨＸ３９４１ＨＰマイクロカプセル型イミダゾール）
ｅ．シリコーン粘着剤（東レ・ダウコーニング社製ＳＤ４５８０）
ｆ．シランカップリング剤（信越化学社製ＫＢＭ４０３）
ｇ．アクリル樹脂（三菱レーヨン社製ダイヤナール）
ｈ．エポキシ変性シリコーン樹脂（東レ・ダウコーニング社製ＢＹ１６－８５５）
ｉ．ナフタレン型エポキシ樹脂（大日本インキ社製ＨＰ－４０３２） <Examples 1 to 9>, <Comparative Examples 1 to 3>
Each of the adhesive compositions having compositions 1 to 10 shown in Table 2 below was dissolved in an ethyl acetate solvent at a concentration of 50% by mass, applied onto PET having a thickness of 50 μm, and at 60 ° C. in air. After drying for 10 minutes, the ethyl acetate solvent was volatilized to produce an adhesive film having a thickness of 25 μm.
The volume% of the conductive particles indicates the volume% occupied by the conductive particles in the entire adhesive (conductive particles + organic binder). The volume% of each component of the organic binder is the volume% of each component in the organic binder that does not contain conductive particles.
In Table 2, the following were used for each component of the organic binder in the adhesive:
a. Bisphenol A type epoxy resin (AER2600 manufactured by Asahi Kasei Chemicals)
b. Dicyclopentadiene-type epoxy resin (HP7200, manufactured by Dainippon Ink, Inc.)
c. Bisphenol A type phenoxy resin (PKHC manufactured by InChem Corporation (Rock Hill, South Carolina, USA))
d. Latent curing agent (HX3941HP microcapsule type imidazole manufactured by Asahi Kasei Epoxy Co., Ltd.)
e. Silicone adhesive (SD4580 manufactured by Toray Dow Corning)
f. Silane coupling agent (Shin-Etsu Chemical KBM403)
g. Acrylic resin (Dianar manufactured by Mitsubishi Rayon)
h. Epoxy-modified silicone resin (BY16-855 manufactured by Toray Dow Corning)
i. Naphthalene type epoxy resin (HP-4032, manufactured by Dainippon Ink and Company)
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
（接続体構造性能）
１．硬化率測定
　未硬化の接着剤を、示差走査熱量測定装置（ＤＳＣ）で室温から２５０℃まで１０℃／ｍｉｎで昇温させた。そのときに発生する発熱量を、接着剤が１００％反応した場合の熱量とした。次に、実際の接続温度と接続時間で、未硬化の接着剤をシリコーンオイルバスに浸漬させることにより、実際の硬化度合いと同等に硬化させた。そして、その実際の硬化度合いと同等に硬化させた接着剤を、ＤＳＣで２５０℃まで１０℃/ｍｉｎで昇温させて完全に硬化させたときに発生した発熱量から硬化率を、以下のように算出した。
硬化率＝（未硬化接着剤を２５０℃まで硬化した発熱量－シリコーンオイルバスに浸漬させた後のＤＳＣで２５０℃まで硬化した発熱量）／（未硬化接着剤を２５０℃まで硬化した発熱量）×１００％ (Connector structure performance)
1. Curing rate measurement The uncured adhesive was heated at 10 ° C./min from room temperature to 250 ° C. with a differential scanning calorimeter (DSC). The amount of heat generated at that time was defined as the amount of heat when the adhesive reacted 100%. Next, the uncured adhesive was immersed in a silicone oil bath at the actual connection temperature and connection time, thereby being cured to the same extent as the actual curing degree. Then, the curing rate is calculated as follows from the calorific value generated when the adhesive cured to the same degree as the actual curing degree is heated at 10 ° C./min up to 250 ° C. by DSC and completely cured. Calculated.
Curing rate = (Heat generation amount of uncured adhesive cured to 250 ° C.−Heat generation amount cured to 250 ° C. by DSC after being immersed in silicone oil bath) / (Heat generation amount of uncured adhesive cured to 250 ° C.) ) X 100%
２．太陽電池セルの反り量
　接着剤の硬化後にセルの凸部を上にして平滑面状に設置し、平滑面から凹部側の銅成分を有する配線までの距離の最大値を測定し、反りの大きさとした。１０回測定し、その平均の反りの大きさを、セル面上のタブ線両端までの長さで割ることで、１ｃｍあたりの反り量を算出した。測定は５０℃の環境下にて実施した。 2. The amount of warpage of the solar battery cell After the adhesive is cured, the cell's convex part is placed on a smooth surface, and the maximum distance from the smooth surface to the wiring having the copper component on the concave side is measured. Say it. The measurement was performed 10 times, and the amount of warpage per 1 cm was calculated by dividing the average warpage size by the length to both ends of the tab line on the cell surface. The measurement was performed in an environment of 50 ° C.
３．基板の割れ、接続部の導電性の測定
　接着剤フィルムを、下記表３に示す厚さを有するシリコン基板に銀ペーストで形成された厚み２０μｍの表面電極導電配線上に軽く貼り、ＰＥＴフィルムを剥がした後、接着剤を挟んでタブ線を表面電極導電配線と向かい合わせて、表３に示した圧力で加圧しながら、接着剤の温度が表３に示した加熱温度になるように、１６秒に亘ってタブ線を加圧及び加熱で接続した。加熱及び加圧後、加圧箇所を光学顕微鏡で観察して、基板の割れの程度を、下記基準にて評価した。
基板割れ箇所　なし　　　　　Ａ
基板割れ箇所　１～２箇所　　Ｂ
基板割れ箇所　３～４箇所　　Ｃ
基板割れ箇所　５箇所以上　　Ｄ
　また、タブ線と基板により接着剤を挟んだ部分を４端子抵抗測定で測定し、初期導電性を下記基準にて評価した。
抵抗値１０ｍΩ未満　　　　　　　　Ａ
抵抗値１０ｍΩ以上２０ｍΩ未満　　Ｂ
抵抗値２０ｍΩ以上４０ｍΩ未満　　Ｃ
抵抗値４０ｍΩ以上　　　　　　　　Ｄ 3. Measurement of conductivity of substrate crack and connection part Adhesive film is lightly pasted on a 20 μm thick surface electrode conductive wiring formed of silver paste on a silicon substrate having the thickness shown in Table 3 below, and the PET film is peeled off. After that, the tab wire is opposed to the surface electrode conductive wiring with the adhesive interposed therebetween, and the pressure of the adhesive shown in Table 3 is applied, and the temperature of the adhesive is set to the heating temperature shown in Table 3 for 16 seconds. The tab wire was connected by pressurization and heating. After heating and pressurization, the pressurization location was observed with an optical microscope, and the degree of cracking of the substrate was evaluated according to the following criteria.
No substrate cracks A
Substrate crack location 1-2 locations B
Substrate breakage 3-4 places C
Substrate breakage 5 or more D
Moreover, the part which pinched | interposed the adhesive agent with the tab wire and the board | substrate was measured by 4-terminal resistance measurement, and the initial stage electroconductivity was evaluated on the following reference | standard.
Resistance value less than 10mΩ A
Resistance value 10mΩ or more and less than 20mΩ B
Resistance value 20mΩ or more and less than 40mΩ C
Resistance value 40mΩ or more D
　さらに、タブ線と基板により接着剤を挟んだ部分を８５℃及び８５％相対湿度（ＲＨ）の環境下に１０００時間放置した前後に、その部分を４端子抵抗測定で測定し、耐久性試験後導電性を下記基準にて評価した。
放置前後の抵抗値の変化率が２０％未満　　　　　　　Ａ
放置前後の抵抗値の変化率が２０％以上３０％未満　　Ｂ
放置前後の抵抗値の変化率が３０％以上５０％未満　　Ｃ
放置前後の抵抗値の変化率が５０％以上　　　　　　　Ｄ
　実施例１～９及び比較例１～３の接続体構造性能の評価結果を表３に示す。 Furthermore, before and after leaving the part where the adhesive was sandwiched between the tab wire and the substrate in an environment of 85 ° C. and 85% relative humidity (RH) for 1000 hours, the part was measured by 4-terminal resistance measurement, and after the durability test The conductivity was evaluated according to the following criteria.
Less than 20% change rate of resistance before and after being left A
The rate of change in resistance before and after being left is 20% or more and less than 30% B
The rate of change in resistance before and after being left is between 30% and less than 50% C
Change rate of resistance value before and after being left is over 50% D
Table 3 shows the evaluation results of the connection structure performance of Examples 1 to 9 and Comparative Examples 1 to 3.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　表３から明らかな通り、実施例１～９において調製された接続構造体は、十分な接続導電性があり、かつ基板の割れ防止性も良好であった。一方で、比較例１～３において調製された接続構造体は、接続導電性が不十分であるか、及び／又は基板の割れが不良であった。 As is apparent from Table 3, the connection structures prepared in Examples 1 to 9 had sufficient connection conductivity and also had good substrate crack prevention properties. On the other hand, the connection structures prepared in Comparative Examples 1 to 3 had insufficient connection conductivity and / or had poor substrate cracking.
　本発明の接続構造体は、薄型化された太陽電池セルであっても、良好な接続導電性を示し、かつ割れも生じない太陽電池などに利用することができる。 The connection structure of the present invention can be used for a solar cell that exhibits good connection conductivity and does not crack even if it is a thinned solar cell.

Claims (10)

  1. 　基板の厚さが４０μｍ～１９０μｍである太陽電池セルの表面電極導電配線と、タブ線とを、ビッカース硬度が１００ＭＰａ～６００ＭＰａである導電粒子を含む接着剤により接続する接続工程を含む、接続構造体の製造方法。 A connection structure including a connection step of connecting a surface electrode conductive wire of a solar battery cell having a substrate thickness of 40 μm to 190 μm and a tab wire with an adhesive containing conductive particles having a Vickers hardness of 100 MPa to 600 MPa. Manufacturing method.
  2. 　前記導電粒子の酸素含有量が、１０ｐｐｍ～１００００ｐｐｍである、請求項１に記載の接続構造体の製造方法。 The method for manufacturing a connection structure according to claim 1, wherein the oxygen content of the conductive particles is 10 ppm to 10,000 ppm.
  3. 　前記導電粒子が、銀又は銅成分を有する合金である、請求項１又は２に記載の接続構造体の製造方法。 The method for manufacturing a connection structure according to claim 1 or 2, wherein the conductive particles are an alloy having a silver or copper component.
  4. 　前記接着剤は、０．１体積％～２０体積％の導電粒子を含む、請求項１～３のいずれか１項に記載の接続構造体の製造方法。 The method for manufacturing a connection structure according to any one of claims 1 to 3, wherein the adhesive includes 0.1% by volume to 20% by volume of conductive particles.
  5. 　前記接着剤は、熱硬化性樹脂を含み、かつ前記接続工程において加圧及び加熱される、請求項１～４のいずれか１項に記載の接続構造体の製造方法。 The method for manufacturing a connection structure according to any one of claims 1 to 4, wherein the adhesive includes a thermosetting resin and is pressurized and heated in the connection step.
  6. 　請求項１～５のいずれか１項に記載の製造方法によって製造された接続構造体を含む、太陽電池モジュール。 A solar cell module including a connection structure manufactured by the manufacturing method according to any one of claims 1 to 5.
  7. 　太陽電池セルの表面電極導電配線、タブ線、及びそれらを電気的に接続している硬化した接着剤を含む接続構造体の製造方法であって、以下の工程：
    　接着剤を硬化させることによって、接着剤の硬化率を２０％～９０％とする工程
    を含む、前記接続構造体の製造方法。     A method for manufacturing a connection structure including a surface electrode conductive wiring of a solar battery cell, a tab wire, and a cured adhesive electrically connecting them, the following steps:
    A method for producing the connection structure, comprising a step of setting the curing rate of the adhesive to 20% to 90% by curing the adhesive.
  8. 　前記接着剤が硬化した後の、前記太陽電池セルの受光部側が凸面であり、且つ５０℃における前記凸面の反りの大きさが、前記タブ線の両端までの長さ１ｃｍあたり０．０１３～０．３３ｍｍである、請求項７に記載の接続構造体の製造方法。 After the adhesive is cured, the light-receiving portion side of the solar battery cell is a convex surface, and the degree of warpage of the convex surface at 50 ° C. is 0.013-0 per 1 cm length to both ends of the tab wire. The manufacturing method of the connection structure of Claim 7 which is .33 mm.
  9. 　前記硬化した接着剤の弾性率が、０．１～６．０ＧＰａである、請求項７又は８に記載の接続構造体の製造方法。 The method for producing a connection structure according to claim 7 or 8, wherein the cured adhesive has an elastic modulus of 0.1 to 6.0 GPa.
  10. 　前記太陽電池セルの基板の厚さが４０μｍ～１９０μｍである、請求項７～９のいずれか１項に記載の接続構造体の製造方法。 The method for manufacturing a connection structure according to any one of claims 7 to 9, wherein a thickness of the substrate of the solar battery cell is 40 袖 m to 190 袖 m.
PCT/JP2012/071497 2011-08-26 2012-08-24 Method for manufacturing solar cell connecting structure WO2013031702A1 (en)

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WO2010122863A1 (en) * 2009-04-21 2010-10-28 ソニーケミカル＆インフォメーションデバイス株式会社 Solar cell module and method for manufacturing same
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WO2011162137A1 (en) * 2010-06-22 2011-12-29 ソニーケミカル＆インフォメーションデバイス株式会社 Bonded material, and process for production thereof
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WO2010122863A1 (en) * 2009-04-21 2010-10-28 ソニーケミカル＆インフォメーションデバイス株式会社 Solar cell module and method for manufacturing same
WO2011024662A1 (en) * 2009-08-27 2011-03-03 三洋電機株式会社 Solar cell string and solar cell module using same
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