JP4493514B2 - Photovoltaic module and manufacturing method thereof - Google Patents

Description

The present invention is a photovoltaic device, a photovoltaic module and a manufacturing method thereof, an optical electromotive force module and a manufacturing method thereof.

  2. Description of the Related Art Conventionally, in a photovoltaic device including a plurality of semiconductor layers including a photoelectric conversion layer, a technique for suppressing moisture and the like from entering a semiconductor layer is known (see, for example, Patent Document 1).

In Patent Document 1, in a configuration in which a collector electrode is formed in a predetermined region on the upper surface of a cell including a plurality of semiconductor layers including a photoelectric conversion layer, a moisture-proof layer is provided on the upper surface of the cell so as to cover the collector electrode. A technique for suppressing moisture and the like from entering a semiconductor layer forming a cell by forming the cell is disclosed.
JP 10-107308 A

  However, in Patent Document 1, the following inconvenience occurs when a tab electrode or the like is connected to the collecting electrodes of a plurality of photovoltaic devices to form a unit. That is, in Patent Document 1, when the moisture-proof layer is formed, the moisture-proof layer is formed on the region where the tab electrode of the collector electrode is connected in order to connect the collector electrode and the tab electrode in a later unitization step. Inconvenience arises in that a mask must be formed so as not to occur. As a result, when a plurality of photovoltaic devices are connected by tab electrodes to form a unit, there is a problem that it is difficult to simplify the manufacturing process of the photovoltaic device.

The present invention has been made to solve the above problems, in the case of unitized connected by tab electrodes photovoltaic device of multiple, which can simplify the manufacturing process It is to provide a photovoltaic module and a manufacturing method thereof .

Means for Solving the Problems and Effects of the Invention

The photovoltaic module of the present invention is a photovoltaic module including a plurality of photovoltaic devices connected by tab electrodes, and the photovoltaic device is a finger formed in a predetermined region on the light incident surface. A collector electrode having an electrode portion and a bus bar electrode portion, and a silicon oxide film formed on the light incident surface so as to cover both the finger electrode portion and the bus bar electrode portion of the collector electrode. The tab electrode is disposed on the first portion located on the upper surface of the bus bar electrode portion of the collector electrode of the silicon oxide film, while containing fine particles made of a material whose etching rate by the flux is higher than that of silicon oxide. In the first portion of the silicon oxide film, fine particles are etched by the flux, so that a part of the upper surface of the bus bar electrode portion of the collector electrode is exposed. , The bus bar electrode portion and the tab electrode of the collector electrode, particles of the silicon oxide film is connected by fusion layer through the etched portion.

In the photovoltaic module of the present invention , as described above , the silicon oxide film is formed on at least the light incident surface of the plurality of semiconductor layers including the photoelectric conversion layer so as to cover both the finger electrode portion and the bus bar electrode portion of the collector electrode. When the sodium contained in the glass substrate constituting the surface protective material is eluted due to the formation of water through the back surface protective material and the filler and reaching the surface protective material, Even when the photovoltaic device is reached via the filler, the silicon oxide film can suppress the elution of sodium eluted into the semiconductor layer located below the silicon oxide film.

In addition , by containing fine particles made of a material whose etching rate by flux is larger than that of silicon oxide in the silicon oxide film, by applying a soldering flux on the silicon oxide film located on the collector electrode, Since the fine particles contained in the silicon oxide film can be selectively etched, a part of the upper surface of the collector electrode can be exposed. As a result, when the collector electrode and the tab electrode are connected, the fusion layer is embedded in the etched portion of the silicon oxide film so that the collector electrode and the tab electrode are connected by the embedded fusion layer. Can be electrically connected. Therefore, when a plurality of photovoltaic devices are connected by tab electrodes to form a unit, when the silicon oxide film is formed, the tab electrode of the collector electrode is connected to connect the collector electrode and the tab electrode. It is not necessary to form a mask so that a silicon oxide film is not formed on the region to be formed. As a result, when a plurality of photovoltaic devices are connected by tab electrodes to form a unit, the manufacturing process of the photovoltaic module can be simplified. In addition, since the fusion layer is embedded in the portion where the fine particles of the silicon oxide film are etched, the collector electrode and the tab electrode can be connected by the embedded fusion layer, so that the tab is formed on the silicon oxide film. Even if the electrode is disposed, sufficient adhesion strength can be obtained between the collector electrode and the tab electrode.

Good Mashiku, said microparticles are microparticles made of ZnO. With this configuration, ZnO, which is a fine particle material, is a material whose etching rate by flux is higher than that of silicon oxide, so that the fine particles contained in the silicon oxide film can be easily selectively etched by the flux. Can do. In addition, since ZnO, which is a material of fine particles, is a material that absorbs UV light (ultraviolet rays), the amount of UV light transmitted through the silicon oxide film is reduced by containing fine particles of ZnO in the silicon oxide film. be able to. In this case , when the collector electrode contains a material that deteriorates due to the irradiation of UV light, it is possible to suppress the deterioration of the collector electrode.

The method for manufacturing a photovoltaic module of the present invention includes a step of forming a plurality of semiconductor layers including a photoelectric conversion layer, and a collector electrode having a finger electrode portion and a bus bar electrode portion on at least a light incident surface of the semiconductor layer. And a polysilazane containing fine particles made of a material whose etching rate by flux is higher than that of silicon oxide so as to cover both the finger electrode portion and the bus bar electrode portion of the collector electrode on the light incident surface. And a step of forming a silicon oxide film containing fine particles on the light incident surface by curing the coating solution by heat treatment, and a step of forming a silicon oxide film. Later, a flux is applied on the first portion of the silicon oxide film corresponding to the bus bar electrode portion of the collector electrode. Etching the fine particles to expose a part of the upper surface of the bus bar electrode portion of the collector electrode, and the bus bar electrode portion of the collector electrode and the tab electrode through the portion where the fine particles of the silicon oxide film are etched. Connecting with a fusion layer .

In this photovoltaic module manufacturing method, as described above, a silicon oxide film is formed by curing a coating solution containing polysilazane as a main component on at least a light incident surface of a plurality of semiconductor layers including a photoelectric conversion layer. Thus, a photovoltaic device capable of suppressing moisture and the like from entering a semiconductor layer located below the silicon oxide film can be formed by the silicon oxide film. In this case, the silicon oxide film by etching speed by the flux contains fine particles made larger material than silicon oxide, by applying a flux for soldering on the silicon oxide film located collector superb Since the fine particles contained in the silicon oxide film can be selectively etched, a part of the surface of the collector electrode can be exposed. As a result, when the collector electrode and the tab electrode are connected, the fusion layer is embedded in the etched portion of the silicon oxide film so that the collector electrode and the tab electrode are connected by the embedded fusion layer. Can be electrically connected. Therefore, when a plurality of photovoltaic devices are connected by tab electrodes to form a unit, when the silicon oxide film is formed, the tab electrode of the collector electrode is connected to connect the collector electrode and the tab electrode. It is not necessary to form a mask so that a silicon oxide film is not formed on the region to be formed. As a result, when a plurality of photovoltaic devices are connected by tab electrodes to form a unit, the manufacturing process of the photovoltaic module can be simplified. In addition, since the fusion layer is embedded in the portion where the fine particles of the silicon oxide film are etched, the collector electrode and the tab electrode can be connected by the embedded fusion layer, so that the tab is formed on the silicon oxide film. Even if the electrode is disposed, sufficient adhesion strength can be obtained between the collector electrode and the tab electrode .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Figure 1 is a perspective view showing a structure of a photovoltaic device used in the implementation form of the present invention. FIG. 2 is a cross-sectional view showing the structure of the photovoltaic module of this embodiment using the photovoltaic device shown in FIG. Figure 3 is an enlarged view of the tab electrodes showed the connected state to the bus bar electrode of the surface-side collecting electrodes of the optical electromotive force device shown in FIG. First, with reference to FIGS. 1 to 3, description will be given of a structure of an optical electromotive force module that by the implementation form.

In the optical electromotive force device 1, as shown in FIG. 1, which has a thickness of resistivity of about 300μm to about 1 [Omega · cm, the (100) on the upper surface of the n-type single crystal silicon substrate 2 having a surface, about A substantially intrinsic i-type amorphous silicon layer 3 having a thickness of 10 nm to about 20 nm is formed. The n-type single crystal silicon substrate 2 is an example of the “photoelectric conversion layer” and “semiconductor layer” in the present invention. The i-type amorphous silicon layer 3 is an example of the “semiconductor layer” in the present invention. A p-type amorphous silicon layer 4 having a thickness of about 10 nm to about 20 nm is formed on the i-type amorphous silicon layer 3. The p-type amorphous silicon layer 4 is an example of the “semiconductor layer” in the present invention.

  On the p-type amorphous silicon layer 4, a translucent conductive film 5 made of an ITO (Indium Tin Oxide) film having a thickness of about 80 nm to about 120 nm is formed. In a predetermined region on the upper surface of the translucent conductive film 5, a surface-side collector electrode 6 made of an epoxy resin into which fine silver (Ag) powder is kneaded is formed. The surface-side collector electrode 6 is an example of the “collector electrode” in the present invention. The surface-side collector electrode 6 has a plurality of finger electrode portions 6a for collecting current and a bus bar electrode portion 6b for collecting current collected in the finger electrode portion 6a. The bus bar electrode portion 6b is formed to extend in a predetermined direction. The plurality of finger electrode portions 6a are arranged so as to be spaced apart from each other and are formed to extend in a direction orthogonal to the direction in which the bus bar electrode portion 6b extends. Further, the finger electrode portion 6a and the bus bar electrode portion 6b of the surface side collector electrode 6 have a thickness of about 10 μm to about 30 μm and a width of about 100 μm to about 500 μm.

Here, in the present embodiment, silicon containing fine particles of ZnO on the upper surface of the translucent conductive film 5 so as to cover both the finger electrode portion 6a and the bus bar electrode portion 6b of the front-side collector electrode 6. An oxide film 7 is formed. ZnO which is a fine particle material contained in the silicon oxide film 7 is a material whose etching rate by flux (for example, pH = about 1.2) is higher than that of silicon oxide. The average particle diameter of the ZnO particles contained in the silicon oxide film 7 is about 0.005 μm or more and about 0.1 μm or less, and the volume ratio of the ZnO particles in the silicon oxide film 7 is about 81. % Or less. The thickness of the silicon oxide film 7 is not less than about 0.01 μm and not more than about 6 μm.

  Further, on the lower surface of the n-type single crystal silicon substrate 2, a substantially intrinsic i-type amorphous silicon layer 8 having a thickness of about 10 nm to about 20 nm and an n-type non-crystal having a thickness of about 10 nm to about 20 nm are formed. A crystalline silicon layer 9 is sequentially formed. The i-type amorphous silicon layer 8 and the n-type amorphous silicon layer 9 are examples of the “semiconductor layer” in the present invention. On the lower surface of the n-type amorphous silicon layer 9, a translucent conductive film 10 made of an ITO film having a thickness of about 80 nm to about 120 nm is formed.

  Further, in a predetermined region on the lower surface of the translucent conductive film 10, a back-side collector electrode 11 made of an epoxy resin in which fine silver (Ag) powder is kneaded is formed. The back surface side collector electrode 11 has a finger electrode portion 11a and a bus bar electrode portion 11b formed in the same shape as the finger electrode portion 6a and the bus bar electrode portion 6b of the surface side collector electrode 6 described above. That is, the bus bar electrode portion 11b is formed to extend in a predetermined direction. Further, the plurality of finger electrode portions 11a are arranged at a predetermined interval from each other, and are formed to extend in a direction orthogonal to the extending direction of the bus bar electrode portion 11b. In addition, the finger electrode portion 11a and the bus bar electrode portion 11b of the back-side collector electrode 11 have a thickness of about 10 μm to about 30 μm and a width of about 100 μm to about 500 μm.

Further, as shown in FIGS. 2 and 3, the photovoltaic module 21 of the present embodiment using the optical electromotive force device 1 includes a plurality of photovoltaic device 1. Each of the plurality of photovoltaic devices 1 has a thickness of about 150 μm, and is adjacent to another photovoltaic device 1 via a tab electrode 22 made of a copper foil covered with solder having a thickness of about 30 μm. Connected with. The end portion side of the tab electrode 22 is disposed on the bus bar electrode portion 6 b (see FIG. 3) of the surface-side collector electrode 6 of the predetermined photovoltaic device 1 via the silicon oxide film 7.

Here, as shown in FIG. 3, in the region corresponding to the bus bar electrode portion 6b of the front-side collector electrode 6 of the silicon oxide film 7, fine particles made of ZnO are etched by flux. Therefore, a part of the surface of the bus bar electrode portion 6b of the surface side collector electrode 6 is exposed in a region corresponding to the bus bar electrode portion 6b of the surface side collector electrode 6 of the silicon oxide film 7. Also, the silicon oxide film in which the content of fine particles of ZnO in the silicon oxide film 7 located on the bus bar electrode part 6b of the surface side collector electrode 6 is located on a region other than the bus bar electrode part 6b of the surface side collector electrode 6 7 is smaller than the content of fine particles of ZnO. A solder layer 23 is embedded in a portion of the silicon oxide film 7 where the fine particles of ZnO are etched, and the embedded solder layer 23 allows the bus bar electrode portion 6b and the tab of the surface side collector electrode 6 to be tabbed. The electrode 22 is connected. The solder layer 23 is an example of the “fusion layer” in the present invention.

  Note that also on the back surface side, the bus bar electrode portion 11b (see FIG. 1) of the back surface side collecting electrode 11 and the tab electrode 22 are connected by a solder layer (not shown).

  Further, as shown in FIG. 2, the plurality of photovoltaic devices 1 connected by the tab electrode 22 are covered with a filler 24 made of EVA (Ethylene Vinyl Acetate). A surface protective material 25 made of a glass substrate is provided on the upper surface of the filler 24. A back surface protective material 26 made of PVF (Poly Vinyl Fluoride) is provided on the lower surface of the filler 24.

In the present embodiment, as described above, by forming the silicon oxide film 7 on the upper surface of the translucent conductive film 5, moisture that has passed through the back surface protective material 26 and the filler 24 reaches the surface protective material 25. Even if sodium contained in the glass substrate constituting the surface protective material 25 is eluted due to the fact, even if the eluted sodium reaches the photovoltaic device 1 through the filler 24, the silicon oxide film 7 can suppress the elution of sodium eluted into each semiconductor layer located below the silicon oxide film 7. In this case, in this embodiment, the silicon oxide film 7 contains fine particles of ZnO whose etching rate by flux is higher than that of silicon oxide, so that the silicon oxide located on the bus bar electrode portion 6b of the surface-side collector electrode 6 can be obtained. By applying a soldering flux on the film 7, the fine particles of ZnO contained in the silicon oxide film 7 can be selectively etched, so that the bus bar electrode portion 6b of the surface side collector electrode 6 can be A part of the upper surface can be exposed. As a result, when the bus bar electrode portion 6b of the front-side collector electrode 6 and the tab electrode 22 are connected, the solder layer 23 is embedded in the portion of the silicon oxide film 7 where the fine particles of ZnO have been etched. The solder layer 23 can electrically connect the bus bar electrode portion 6 b of the front-side collector electrode 6 and the tab electrode 22. Therefore, when the plurality of photovoltaic devices 1 are connected by the tab electrode 22 to form a unit, when the silicon oxide film 7 is formed, the bus bar electrode portion 6b of the surface-side collector electrode 6 and the tab electrode 22 are connected. Therefore, it is not necessary to form a mask so that the silicon oxide film 7 is not formed on the region to which the tab electrode 22 of the bus bar electrode portion 6b of the front-side collector electrode 6 is connected. As a result, the manufacturing process of the photovoltaic module 21 can be simplified when a plurality of photovoltaic devices 1 are connected by the tab electrode 22 to be unitized.

Further, the embedded solder layer 23 in a portion microparticles consisting of ZnO of divorced oxide film 7 is etched, connect the bus bar electrode portion 6b and the tab electrode 22 of the surface-side collecting electrodes 6 by the embedded solder layer 23 As a result, even if the tab electrode 22 is disposed on the silicon oxide film 7, sufficient adhesion strength can be obtained between the bus bar electrode portion 6 b of the surface side collector electrode 6 and the tab electrode 22.
Further, in the present embodiment, by containing fine particles of ZnO in the silicon oxide film 7, since the fine particle material ZnO is a material that absorbs UV light (ultraviolet rays), it passes through the silicon oxide film 7. The amount of UV light can be reduced. Thereby, even if it uses the surface side collector electrode 6 containing the material (epoxy resin) which deteriorates by irradiation of UV light, it can suppress that the surface side collector electrode 6 deteriorates.

Further, the average particle size of the fine particles of ZnO contained in divorced oxide film 7, by setting below about 0.1 [mu] m, due to the average particle diameter of the fine particles of ZnO is greater than about 0.1 [mu] m Thus, it is possible to suppress the inconvenience that light other than UV light incident on the silicon oxide film 7 is scattered and reflected by fine particles made of ZnO and emitted to the outside. Accordingly, it is possible to suppress a decrease in the amount of light other than UV light that passes through the silicon oxide film 7 and enters the n-type single crystal silicon substrate (photoelectric conversion layer) 2. It can suppress that the output characteristic of this falls.

Further, the thickness of divorced oxide film 7, by setting below about 6 [mu] m, the thickness of the silicon oxide film 7 due to the greater than about 6 [mu] m, the surface-side collecting electrodes 6 permeability thereof as an underlying layer Generation | occurrence | production of the problem that contact resistance with the photoconductive film 5 becomes high can be suppressed. Specifically, when the silicon oxide film 7 is formed by curing a coating solution containing polysilazane, when the coating solution (silicon oxide film 7) is cured, the coating solution (silicon oxide film 7) Since an external force is applied to the surface-side collector electrode 6 due to internal stress, the contact state between the surface-side collector electrode 6 and the translucent conductive film 5 that is the underlying layer changes. In this case, if the thickness of the silicon oxide film 7 is larger than about 6 μm, the external force applied to the surface-side collector electrode 6 also increases, so that the gap between the surface-side collector electrode 6 and the translucent conductive film 5 that is the underlying layer is increased. The contact state also greatly changes. Therefore, by setting the thickness of the silicon oxide film 7 to about 6 μm or less, it is possible to suppress a change in the contact state between the surface-side collector electrode 6 and the translucent conductive film 5 that is the underlying layer. Since it can do, it can suppress that the contact resistance of the surface side collector electrode 6 and the translucent conductive film 5 which is the base layer becomes high.

Further, the thickness of divorced oxide film 7, by setting the above about 0.01 [mu] m, the thickness of the silicon oxide film 7 due to less than about 0.01 [mu] m, through the silicon oxide film 7, It is possible to prevent the inconvenience that moisture or the like easily enters each semiconductor layer located below the silicon oxide film 7.

Figure 4 is a sectional view for illustrating a manufacturing process of a photovoltaic Chikaramo joules by the implementation of the invention. Next, with reference to FIGS. 1-4, the manufacturing process of the photovoltaic module 21 by this embodiment is demonstrated.

  When producing the photovoltaic device 1 shown in FIG. 1, first, an n-type single crystal silicon substrate 2 having a resistivity of about 1 Ω · cm and a thickness of about 300 μm and having a (100) plane is formed. Impurities are removed by washing. Then, an RF plasma CVD (Chemical Vapor Deposition) method is used to form an i-type amorphous silicon layer 3 having a thickness of about 10 nm to about 20 nm and a thickness of about 10 nm to about 20 nm on the n-type single crystal silicon substrate 2. A p-type amorphous silicon layer 4 having n is sequentially formed. The formation conditions of the i-type amorphous silicon layer 3 and the p-type amorphous silicon layer 4 are as follows: frequency: about 13.56 MHz, formation temperature: about 100 ° C. to about 300 ° C., reaction pressure: about 5 Pa to about 100 Pa, RF power: about 1 mW / cm2 to about 500 mW / cm2. Note that p-type dopants for forming the p-type amorphous silicon layer 4 include group III elements B, Al, Ga, and In. Then, at the time of forming the p-type amorphous silicon layer 4, a compound gas containing at least one of the above-described p-type dopants is mixed with a source gas such as SiH4 (silane) gas to thereby form p-type amorphous silicon. Layer 4 can be formed.

  Next, an RF plasma CVD method is used to form an i-type amorphous silicon layer 8 having a thickness of about 10 nm to about 20 nm and a thickness of about 10 nm to about 20 nm on the lower surface of the n-type single crystal silicon substrate 2. An n-type amorphous silicon layer 9 is sequentially formed. In addition, as an n-type dopant at the time of forming the n-type amorphous silicon layer 9, P, N, As and Sb which are group 5 elements are mentioned. Then, when the n-type amorphous silicon layer 9 is formed, n-type amorphous silicon is mixed by mixing a compound gas containing at least one of the above-described n-type dopants with a source gas such as SiH 4 (silane) gas. It is possible to form layer 9. The formation conditions of the i-type amorphous silicon layer 8 and the n-type amorphous silicon layer 9 are the same as the formation conditions of the i-type amorphous silicon layer 3 and the p-type amorphous silicon layer 4 described above. .

  Next, a light-transmitting conductive film 5 made of an ITO film is formed on the p-type amorphous silicon layer 4 by sputtering. When forming the translucent conductive film 5, a target made of a sintered body of In2O3 powder containing about 5% by mass of SnO2 powder is used as a cathode (not shown) in a chamber (not shown) of a sputtering apparatus (not shown). (Not shown). In this case, it is possible to change the amount of Sn in the ITO film by changing the amount of SnO2 powder. Here, the amount of Sn with respect to In is preferably about 1% by mass to about 10% by mass, and more preferably about 2% by mass to about 7% by mass. The sintered density of the target is preferably about 90% or more. The translucent conductive film 5 is formed using a sputtering apparatus capable of applying a strong magnetic field of about 300 Gauss to about 3000 Gauss with a magnet.

  Next, the n-type single crystal silicon substrate 2 is arranged so as to be parallel to and opposed to the cathode. Then, the chamber is evacuated and then heated using a heater (not shown) until the substrate temperature reaches about 200 ° C. Thereafter, with the substrate temperature maintained at about 200 ° C., a mixed gas of Ar gas and O 2 gas is supplied into the chamber to maintain the pressure at about 0.4 Pa to about 1.3 Pa, and Discharging is started by applying DC power of 0.5 kW to about 2 kW. At this time, the n-type single crystal silicon substrate 2 is held stationary with respect to the cathode, and the deposition rate is set to about 10 nm / min to about 80 nm / min. Thereby, the translucent conductive film 5 made of an ITO film having a thickness of about 80 nm to about 120 nm is formed.

  Next, a transparent process comprising an ITO film having a thickness of about 80 nm to about 120 nm is formed on the lower surface of the n-type amorphous silicon layer 9 by using a formation process similar to the formation process of the translucent conductive film 5 described above. A photoconductive film 10 is formed.

  Next, a paste made of an epoxy resin in which a fine powder of silver (Ag) is kneaded is applied to a predetermined region on the upper surface of the translucent conductive film 5 by screen printing. Thereafter, a paste made of an epoxy resin in which fine silver (Ag) powder is kneaded is cured by performing a heat treatment for about 80 minutes under a temperature condition of about 200 ° C. Accordingly, the predetermined region on the upper surface of the translucent conductive film 5 is made of an epoxy resin in which fine powder of silver (Ag) is kneaded, and has a plurality of finger electrode portions 6a and bus bar electrode portions 6b. A front-side collector electrode 6 is formed. At this time, the bus bar electrode portion 6b is formed to extend in a predetermined direction. Further, the plurality of finger electrode portions 6a are formed so as to be arranged at a predetermined interval from each other and to extend in a direction orthogonal to the direction in which the bus bar electrode portion 6b extends. Further, the finger electrode portion 6a and the bus bar electrode portion 6b of the surface side collecting electrode 6 are formed to have a thickness of about 10 μm to about 30 μm and a width of about 100 μm to about 500 μm.

  Next, an epoxy resin in which a fine powder of silver (Ag) is kneaded into a predetermined region on the lower surface of the translucent conductive film 10 using a formation process similar to the formation process of the surface-side collector electrode 6 described above. And a back-side collector electrode 11 having a plurality of finger electrode portions 11a and bus bar electrode portions 11b. At this time, the finger electrode portion 11a and the bus bar electrode portion 11b of the back surface side collector electrode 11 are formed to have the same shape as the finger electrode portion 6a and the bus bar electrode portion 6b of the surface side collector electrode 6 described above.

Next, in this embodiment, a coating solution containing polysilazane containing fine particles of ZnO as a main component is prepared. Dibutyl ether is used as a solvent for the coating solution. Moreover, the ratio of the sum total of the mass of the polysilazane and the fine particles made of ZnO with respect to the mass of the solvent is set to about 2 mass% to about 10 mass%. In addition, the ratio of the mass of the fine particles made of ZnO to the total mass of the fine particles of polysilazane and ZnO is set to about 95% by mass or less. Further, the average particle diameter of the fine particles made of ZnO is set to about 0.005 μm or more and about 0.1 μm or less.

  As the coating solution, a solution to which palladium (Pd) having a particle size of about 0.05 μm or less is added is used. Thus, by adding palladium (Pd) to the coating solution, the curing temperature of the coating solution can be lowered.

  Next, the above-described fine particles of ZnO are contained on the upper surface of the translucent conductive film 5 by using a spray method so as to cover both the finger electrode portion 6a and the bus bar electrode portion 6b of the front-side collector electrode 6. A coating solution containing polysilazane as a main component is applied. Thereafter, a coating solution containing polysilazane containing fine particles of ZnO as a main component is cured by performing a heat treatment for about 1 hour under a temperature condition of about 200 ° C. in an air atmosphere. Thereby, a silicon oxide film 7 containing fine particles of ZnO is formed on the upper surface of the translucent conductive film 5 so as to cover both the finger electrode portion 6a and the bus bar electrode portion 6b of the front-side collector electrode 6. Is done.

At this time, in this embodiment, the silicon oxide film 7 is formed to have a thickness of about 0.01 μm or more and about 6 μm or less. In this way, by forming the silicon oxide film 7 to be about 6 μm or less, when the coating solution (silicon oxide film 7) is cured, the coating solution (silicon oxide film 7) is deformed and the surface side collection is performed. Since it can suppress that the external force added to the electrode 6 becomes large, it can suppress that the contact state between the surface side collector electrode 6 and the translucent conductive film 5 which is the base layer changes. . As a result, the contact state between the surface-side collector electrode 6 and the light-transmitting conductive film 5 that is the underlying layer changes, so that the surface-side collector electrode 6 and the light-transmitting conductive material that is the underlying layer are changed. Generation | occurrence | production of the problem that contact resistance with the film | membrane 5 becomes high can be suppressed.

When the silicon oxide film 7 is formed as described above, the volume ratio of the fine particles made of ZnO in the silicon oxide film 7 is about 81% or less. In this manner, the optical electromotive force device 1 shown in FIG. 1 is formed.

When the photovoltaic module 21 according to the present embodiment using the photovoltaic device 1 is manufactured, first, a plurality of photovoltaic devices 1 shown in FIG. 1 are prepared. Then, a flux (not shown) is applied to a region corresponding to the bus bar electrode portion 6 b of the surface side collector electrode 6 on the silicon oxide film 7. The components of the flux are glutamic acid hydrochloride: about 5% to about 10%, urea: about 4% to about 10%, and water: about 80% or more. The pH of the flux is about pH = 1.2.

At this time , in the present embodiment, as shown in FIG. 4, in the region corresponding to the bus bar electrode portion 6b of the front-side collector electrode 6 of the silicon oxide film 7, fine particles made of ZnO contained in the silicon oxide film 7 are fluxed. Is selectively etched. Thereby, in this embodiment, a part of upper surface of the bus bar electrode part 6b of the surface side collector electrode 6 can be exposed in a region corresponding to the bus bar electrode part 6b of the surface side collector electrode 6 of the silicon oxide film 7. . As a result, in the subsequent soldering step, the solder layer 23 is embedded in the portion of the silicon oxide film 7 where the fine particles of ZnO are etched, and the embedded solder layer 23 causes the bus bar electrode portion of the surface-side collector electrode 6 to be embedded. 6b and the tab electrode 22 can be electrically connected. Therefore, in this embodiment, when the silicon oxide film 7 is formed, in order to connect the bus bar electrode portion 6b of the surface side collector electrode 6 and the tab electrode 22, the tab of the bus bar electrode portion 6b of the surface side collector electrode 6 is used. Since it is not necessary to form a mask so that the silicon oxide film 7 is not formed on the region to which the electrode 22 is connected, the manufacturing process can be simplified.

  Thereafter, as shown in FIG. 2 and FIG. 3, each of the plurality of photovoltaic devices 1 is connected to another adjacent photovoltaic device via a tab electrode 22 made of a copper foil having a thickness of about 150 μm. Connect with 1. Specifically, one end side of the tab electrode 22 on which the solder layer 23 having a thickness of about 30 μm is coated on the front surface and the back surface is placed on the bus bar electrode portion 6 b of the front surface side collecting electrode 6 of the predetermined photovoltaic device 1. In addition, the silicon oxide film 7 is interposed therebetween. Further, the other end side of the tab electrode 22 is disposed on the bus bar electrode portion 11 b (see FIG. 1) of the back surface side collecting electrode 11 of another photovoltaic device 1 adjacent to the predetermined photovoltaic device 1.

Thereafter , as shown in FIG. 3, by performing a heat treatment, the solder layer 23 coated on the lower surface of the tab electrode 22 is melted, so that the fine particles made of ZnO of the silicon oxide film 7 are etched. A solder layer 23 is embedded. As a result, the bus bar electrode portion 6 b of the front-side collector electrode 6 and the tab electrode 22 are connected by the solder layer 23. Therefore, in the present embodiment, even if the tab electrode 22 is disposed on the silicon oxide film 7, sufficient adhesion strength can be obtained between the bus bar electrode portion 6 b of the surface-side collector electrode 6 and the tab electrode 22. Also on the back surface side, the solder layer (not shown) coated on the upper surface of the tab electrode 22 is melted by the above-described heat treatment, so that the bus bar electrode portion 11b of the back surface side collecting electrode 11 (see FIG. 1). And the tab electrode 22 are connected.

Finally, as shown in FIG. 2, a plurality of photovoltaic devices 1 connected later by an EVA sheet and a tab electrode 22 on a surface protective material 25 made of a glass substrate, and later a filler 24. The EVA sheet and the back surface protective material 26 made of PVF are sequentially laminated. Thereafter, by performing a vacuum laminating process while heating, light electromotive force module 21 that by the present embodiment is formed.

Next, among the effects of the present embodiment described above, an experiment conducted to confirm the effect related to the adhesion strength between the bus bar electrode portion of the front-side collector electrode and the tab electrode will be described. In this confirmation experiment, after producing the photovoltaic devices 1 according to the following Examples 1 to 5 and Comparative Example 1, for each of the produced photovoltaic devices 1, the bus bar electrode portion 6 b and the tab of the front-side collector electrode 6. The adhesion strength between the electrodes 22 was measured.

(Common to Examples 1 to 5 and Comparative Example 1)
[Preparation of samples used to measure adhesion strength]
First, using the process of implementation embodiment described above, actually formed up to the surface-side collecting electrodes 6 of the photovoltaic device 1 shown in FIG. The thickness of each of the i-type amorphous silicon layer 3, the p-type amorphous silicon layer 4, the i-type amorphous silicon layer 8, and the n-type amorphous silicon layer 9 was set to 10 nm. The thickness of each of the translucent conductive films 5 and 10 was set to 100 nm. The thickness of each of the front-side collector electrode 6 and the back-side collector electrode 11 was set to 30 μm.

  Thereafter, a coating solution containing polysilazane as a main component is applied on the upper surface of the light-transmitting conductive film 5 so as to cover the finger electrode portion 6a and the bus bar electrode portion 6b of the surface-side collector electrode 6 by spraying. did. At this time, in Examples 1 to 5, a coating solution containing polysilazane containing fine particles of ZnO as a main component was used as the coating solution. The ratio of the total mass of the polysilazane and the fine particles composed of ZnO to the mass of the solvent was set to 10% by mass. The average particle diameter of the fine particles made of ZnO was set to 0.02 μm.

  In Example 1, the ratio of the mass of the fine particles composed of ZnO to the total mass of the fine particles composed of polysilazane and ZnO was set to 25% by mass.

  In Example 2, the ratio of the mass of the fine particles composed of ZnO to the total mass of the fine particles composed of polysilazane and ZnO was set to 50% by mass.

  In Example 3, the ratio of the mass of the fine particles made of ZnO to the total mass of the fine particles of polysilazane and ZnO was set to 75% by mass.

  In Example 4, the ratio of the mass of the fine particles composed of ZnO to the total mass of the fine particles composed of polysilazane and ZnO was set to 85% by mass.

  In Example 5, the ratio of the mass of the fine particles made of ZnO to the total mass of the fine particles of polysilazane and ZnO was set to 95% by mass.

  Moreover, in Comparative Example 1, unlike Examples 1-5, the coating solution which has as a main component the polysilazane which does not contain the microparticles | fine-particles which consist of ZnO was used as a coating solution.

  Then, the coating solution which has a polysilazane as a main component was hardened by performing the heat processing for 1 hour in 200 degreeC temperature conditions in air | atmosphere. Thereby, the silicon oxide film 7 covering both the finger electrode portion 6a and the bus bar electrode portion 6b of the front-side collector electrode 6 was formed on the upper surface of the translucent conductive film 5. The silicon oxide film 7 was formed to have a thickness of 0.1 μm.

  When the silicon oxide film 7 was formed as described above, in Example 1, the volume ratio of the fine particles made of ZnO in the silicon oxide film 7 was 7%.

  In Example 2, the volume ratio of the fine particles made of ZnO in the silicon oxide film 7 was 18%.

  In Example 3, the volume ratio of the fine particles made of ZnO in the silicon oxide film 7 was 40%.

  In Example 4, the volume ratio of the fine particles made of ZnO in the silicon oxide film 7 was 56%.

  In Example 5, the volume ratio of the fine particles of ZnO in the silicon oxide film 7 was 81%.

  Thus, the photovoltaic apparatus 1 by Examples 1-5 and the comparative example 1 was produced.

  Next, the tab electrode 22 was connected to each surface side collector electrode 6 of Examples 1 to 5 and Comparative Example 1 manufactured as described above.

  Specifically, first, as shown in FIGS. 5 to 10, the silicon oxide film 7 located in the region corresponding to the bus bar electrode portion 6 b of each of the front-side collector electrodes 6 of Examples 1 to 5 and Comparative Example 1 is used. On top, flux (pH = 1.2) (not shown) was applied.

  At this time, in Examples 1 to 5, as shown in FIGS. 5 to 9, in the region corresponding to the bus bar electrode portion 6 b of the surface-side collector electrode 6 of the silicon oxide film 7, it is contained in the silicon oxide film 7. Fine particles made of ZnO were selectively etched by the flux. Thereby, in Examples 1-5, in the area | region corresponding to the bus-bar electrode part 6b of the surface side collector electrode 6 of the silicon oxide film 7, a part of upper surface of the bus-bar electrode part 6b of the surface-side collector electrode 6 was exposed. .

  Here, as shown in FIGS. 5 to 9, in Examples 1 to 5, the higher the volume ratio of the fine particles made of ZnO in the silicon oxide film 7, the more exposed the bus bar electrode portion 6 b of the surface side collector electrode 6. The part became bigger. That is, in the region corresponding to the bus bar electrode portion 6b of the surface side collector electrode 6 of the silicon oxide film 7 of Example 1 (see FIG. 5), the exposed portion of the bus bar electrode portion 6b of the surface side collector electrode 6 was the smallest. . Further, in the region corresponding to the bus bar electrode portion 6b of the surface side collector electrode 6 of the silicon oxide film 7 of Example 5 (see FIG. 9), the exposed portion of the bus bar electrode portion 6b of the surface side collector electrode 6 was the largest. . In Comparative Example 1, as shown in FIG. 10, the surface of the bus bar electrode portion 6 b of the surface side collector electrode 6 is exposed in the region corresponding to the bus bar electrode portion 6 b of the surface side collector electrode 6 of the silicon oxide film 7. There wasn't.

  Thereafter, as shown in FIGS. 11 to 15, the bus bar electrode portion 6 b and the tab electrode 22 of the surface-side collector electrode 6 are connected to the solder layer 23 a through the etched portion of the silicon oxide film 7 made of ZnO. Connected by ~ 23e. In this way, five samples corresponding to each of Examples 1 to 5 used for the measurement of adhesion strength described later were prepared.

  In Comparative Example 1, as shown in FIG. 16, the bus bar electrode portion 6b of the front-side collector electrode 6 was not exposed, so the bus-bar electrode portion 6b of the front-side collector electrode 6 and the tab electrode 22 were connected by the solder layer 23f. Could not connect.

[Measurement of adhesion strength]
Using the samples corresponding to each of Examples 1 to 5 described above, the adhesion strength between the bus bar electrode portion 6b of the front-side collector electrode 6 and the tab electrode 22 was measured. The measurement of the adhesion strength was performed using a measuring device 31 as shown in FIG. Specifically, first, the sample was fixed to the measuring device 31. Further, one end of the tab electrode 22 was bent in a direction perpendicular to the upper surface of the sample, and the bent one end of the tab electrode 22 was sandwiched between the clips 32 of the measuring device 31. Thereafter, the tab electrode 22 was pulled up in a direction perpendicular to the upper surface of the sample by turning the handle 33 of the measuring device 31. Then, the peeling strength when the tab electrode 22 was peeled from the bus bar electrode portion 6 b of the surface side collecting electrode 6 was measured by the measuring instrument 34. In this way, the adhesion strength between the bus bar electrode portion 6b of the front-side collector electrode 6 and the tab electrode 22 was measured. Moreover, in the measurement of the adhesion strength, after measuring the adhesion strength for each of the five samples corresponding to Examples 1 to 5, the average value of the measured adhesion strength of each of the five sheets was calculated. Then, normalization was performed using the adhesion strength between the bus bar electrode portion of the front-side collector electrode not covered with the silicon oxide film and the tab electrode as a reference (“1”). The results are shown in Table 1 below.

  Referring to Table 1 above, it was found that the normalized adhesion strength increases as the volume ratio of the fine particles of ZnO in the silicon oxide film 7 increases. Specifically, in Example 1 in which the volume ratio of the fine particles of ZnO in the silicon oxide film 7 was 7%, the normalized adhesion strength was 0.04. In Example 2 in which the volume ratio of the fine particles of ZnO in the silicon oxide film 7 was 18%, the normalized adhesion strength was 0.12. Further, in Example 3 in which the volume ratio of the fine particles of ZnO in the silicon oxide film 7 was 40%, the normalized adhesion strength was 0.43. In Example 4 where the volume ratio of the fine particles of ZnO in the silicon oxide film 7 was 56%, the normalized adhesion strength was 0.75. In Example 5 in which the volume ratio of the fine particles of ZnO in the silicon oxide film 7 was 81%, the normalized adhesion strength was 0.98. In Comparative Example 1 in which the silicon oxide film 7 did not contain fine particles of ZnO, the normalized adhesion strength between the silicon oxide film 7 and the tab electrode 22 was zero.

  From this result, if the silicon oxide film 7 contains fine particles of ZnO, the fine particles of ZnO can be selectively etched by the flux, so the fine particles of ZnO of the silicon oxide film 7 are etched. It was confirmed that the bus bar electrode portion 6b of the front-side collector electrode 6 and the tab electrode 22 can be connected by the solder layer 23 through the portion.

  The normalized adhesion strength increased as the volume ratio of ZnO particles in the silicon oxide film 7 increased. The silicon oxide film 7 was etched by the flux (the part where the ZnO particles were located). This is considered to be because the bonding area between the solder layer 23 and the bus bar electrode portion 6b of the front-side collector electrode 6 is increased. Accordingly, it is considered that the adhesion strength between the bus bar electrode portion 6b of the front-side collector electrode 6 and the tab electrode 22 can be increased by increasing the amount of fine particles made of ZnO contained in the silicon oxide film 7. It is done.

18 and 19 are graphs showing the relationship between the thickness of a silicon oxide film containing fine particles of ZnO and the normalized spectral sensitivity. Next, with reference to FIGS. 18 and 19, of the effects of the present embodiment described above, it will be described an experiment conducted for confirming the effect on the transmittance of UV light (ultraviolet light).

  In this confirmation experiment, a plurality of samples in which the thickness of the silicon oxide film 7 was changed in the range of 0.1 μm to 2 μm in the configuration of the photovoltaic device 1 of Examples 1, 2, and 5 described above were produced. The spectral sensitivity to UV light (light having a wavelength of 360 nm) and light having a wavelength of 420 nm was measured. Then, normalization was performed using the spectral sensitivity with respect to UV light and light having a wavelength of 420 nm of a photovoltaic device in which a silicon oxide film is not formed as a reference (“1”). In each sample of Examples 1, 2, and 5, the volume ratios of the fine particles of ZnO in the silicon oxide film 7 are 7%, 18%, and 81%, respectively. In each sample of Examples 1, 2, and 5, the average particle diameter of the fine particles made of ZnO contained in the silicon oxide film 7 is 0.02 μm.

  First, as shown in FIG. 18, it was found that the normalized spectral sensitivity to UV light is reduced in any of Examples 1, 2, and 5. That is, it was found that the absorption of UV light in the silicon oxide film 7 is increased by using the silicon oxide film 7 containing fine particles of ZnO in a volume ratio of 7% to 81%. This is presumably because the UV light was absorbed by the fine particles of ZnO contained in the silicon oxide film 7. From this result, it was confirmed that the amount of UV light transmitted through the silicon oxide film 7 can be reduced by containing fine particles of ZnO in the silicon oxide film 7.

  On the other hand, as shown in FIG. 19, in any of Examples 1, 2, and 5, it was found that the normalized spectral sensitivity hardly deteriorated with respect to light having a wavelength of 420 nm. That is, it was found that even when the silicon oxide film 7 containing fine particles of ZnO was used, light with a wavelength of 420 nm was hardly absorbed.

  Further, as shown in FIG. 18, it has been found that the normalized spectral sensitivity to UV light decreases as the volume ratio of the fine particles of ZnO in the silicon oxide film 7 increases. That is, it has been found that the absorption of UV light in the silicon oxide film 7 increases as the volume ratio of the fine particles of ZnO in the silicon oxide film 7 increases. Specifically, when the thickness of the silicon oxide film 7 is the same, the normalized spectral sensitivity of Example 5 in which the volume ratio of the fine particles of ZnO in the silicon oxide film 7 is 81% is the lowest, and the silicon oxide film The normalized spectral sensitivity of Example 1 in which the volume ratio of the fine particles of ZnO in the film 7 was 7% was the highest. This is presumably because the absorption of UV light by fine particles made of ZnO in Example 5 increased compared to Example 1.

  As shown in FIG. 18, in any of Examples 1, 2, and 5, the normalized spectral sensitivity to UV light increases as the thickness of the silicon oxide film 7 containing fine particles of ZnO increases. It turned out to be reduced. That is, it has been found that the absorption of UV light in the silicon oxide film 7 increases as the thickness of the silicon oxide film 7 containing fine particles of ZnO increases. This is considered to be because the amount of fine particles made of ZnO contained in the silicon oxide film 7 is increased by increasing the thickness of the silicon oxide film 7 containing fine particles made of ZnO. However, in Example 5 where the volume fraction of ZnO particles in the silicon oxide film 7 is 81%, the normalized spectral sensitivity hardly changes when the silicon oxide film 7 is changed from 1 μm to 2 μm. It was.

20 and 21 are graphs showing the relationship between the average particle diameter of the fine particles made of ZnO contained in the silicon oxide film and the normalized spectral sensitivity. Next, with reference to FIGS. 20 and 21, of the effects of the present embodiment described above, it will be described an experiment conducted for confirming the effect on the transmittance of light other than UV light.

  In this confirmation experiment, in the configuration of the photovoltaic device 1 of Example 2 described above, the average particle diameter of ZnO particles contained in the silicon oxide film 7 is changed within a range of 0.005 μm to 0.5 μm. A plurality of samples were prepared, and spectral sensitivity to UV light (light having a wavelength of 360 nm) and light having a wavelength of 420 nm was measured. Then, normalization was performed using the spectral sensitivity with respect to UV light and light having a wavelength of 420 nm of a photovoltaic device in which a silicon oxide film is not formed as a reference (“1”). In the sample of Example 2, the volume ratio of the fine particles made of ZnO in the silicon oxide film 7 is 18%. In the sample of Example 2, the thickness of the silicon oxide film 7 is 0.5 μm.

  First, as shown in FIG. 20, when the average particle diameter of the fine particles made of ZnO contained in the silicon oxide film 7 is in the range of 0.005 μm or more and 0.5 μm or less, the normalized spectral sensitivity to UV light is 0. It was found that the UV light was satisfactorily absorbed by the fine particles composed of ZnO.

  Further, as shown in FIG. 21, when the average particle diameter of the fine particles made of ZnO contained in the silicon oxide film 7 is in the range of 0.005 μm or more and 0.1 μm or less, the normalized spectral sensitivity for light having a wavelength of 420 nm. It became clear that the absorption of light having a wavelength of 420 nm by fine particles made of ZnO was suppressed. On the other hand, it was found that when the average particle diameter of the ZnO fine particles contained in the silicon oxide film 7 is larger than 0.1 μm, the normalized spectral sensitivity for light having a wavelength of 420 nm is lower than 0.98. . This is because the light having a wavelength of 420 nm incident on the silicon oxide film 7 is scattered and reflected by the fine particles made of ZnO and emitted to the outside because the average particle size of the fine particles made of ZnO is larger than 0.1 μm. This is probably because

  From this result, in order to reduce the UV light transmitted through the silicon oxide film 7 and increase the light having a wavelength of 420 nm transmitted through the silicon oxide film 7, the fine particles of ZnO contained in the silicon oxide film 7 are increased. It can be said that the average particle size is preferably set to 0.1 μm or less. Currently, there are no fine particles made of ZnO having an average particle size smaller than 0.005 μm. Therefore, the average particle diameter of the fine particles made of ZnO contained in the silicon oxide film 7 may be set to 0.005 μm or more and 0.1 μm or less.

FIG. 22 is a graph showing the relationship between the thickness of the silicon oxide film and the normalized curve factor (FF). Next, with reference to FIG. 22, an experiment conducted for confirming the effect relating to the contact resistance between the surface-side collector electrode and the translucent conductive film among the effects of the present embodiment described above will be described.

  In this confirmation experiment, in the configurations of the photovoltaic devices 1 of Examples 1, 2, 5 and Comparative Example 1 described above, the thickness of the silicon oxide film 7 was changed within a range of 0.01 μm to 7 μm. Samples were prepared and the fill factor (FF) of current-voltage characteristics was measured. Then, normalization was performed with the curve factor (FF) of the photovoltaic device in which the silicon oxide film was not formed as a reference (“1”). In each sample of Examples 1, 2, and 5, the volume ratios of the fine particles of ZnO in the silicon oxide film 7 are 7%, 18%, and 81%, respectively. In each sample of Examples 1, 2, and 5, the average particle diameter of the fine particles made of ZnO contained in the silicon oxide film 7 is 0.02 μm. In the sample of Comparative Example 1, the silicon oxide film 7 does not contain fine particles made of ZnO.

  As shown in FIG. 22, when Comparative Example 1 in which the silicon oxide film 7 does not contain the fine particles of ZnO is compared with Examples 1, 2, and 5 in which the silicon oxide film 7 contains the fine particles of ZnO. If the thickness of the silicon oxide film 7 is the same, the normalized curve factor (FF) of Examples 1, 2, and 5 is higher than the normalized curve factor (FF) of Comparative Example 1. Turned out to be. This is because, in forming the silicon oxide film 7 by curing the coating solution containing polysilazane, the fine particles made of ZnO that do not deform when the coating solution is cured contain the fine particles of Examples 1, 2, and 5. This is probably because the silicon oxide film 7 has a smaller deformation than the silicon oxide film 7 of Comparative Example 1 that does not contain fine particles of ZnO. That is, in Examples 1, 2, and 5, when the silicon oxide film 7 is formed, the coating solution (silicon oxide film 7) is deformed and an external force is applied to the surface-side collector electrode 6, so that the surface side It is considered that the contact state between the collector electrode 6 and the translucent conductive film 5 is suppressed from changing.

  As shown in FIG. 22, in Examples 1, 2, and 5, if the thickness of the silicon oxide film 7 is the same, the lower the volume ratio of the fine particles made of ZnO in the silicon oxide film 7, the normalization is. It was found that the fill factor (FF) was low. That is, the normalized curve factor (FF) of Example 1 in which the volume ratio of the fine particles of ZnO in the silicon oxide film 7 was 7% was the lowest. This is because the coating solution (silicon oxide film 7) is formed when the silicon oxide film 7 is formed by curing the coating solution containing polysilazane because the volume ratio of the ZnO fine particles in the silicon oxide film 7 is low. This is thought to be because the amount of deformation of the increased. In Example 1, it was found that when the thickness of the silicon oxide film 7 is larger than 6 μm, the normalized curve factor (FF) is lower than 0.98.

  From this result, it is considered that the upper limit of the thickness of the silicon oxide film 7 containing fine particles of ZnO is preferably 6 μm or less.

  FIG. 23 is a graph showing the relationship between the thickness of the silicon oxide film and the normalized output. Next, with reference to FIG. 23, an experimental result in which an aqueous solution containing sodium is applied on the upper surface of the silicon oxide film and the output of the photovoltaic device 1 is measured will be described.

  In this experiment, first, a plurality of samples in which the thickness of the silicon oxide film 7 was changed in the range of 0.005 μm to 0.16 μm in the configuration of the photovoltaic device 1 of Examples 1 and 2 described above were produced. At the same time, an aqueous solution (0.5 g) mixed with 0.05% NaHCO 3 was applied to the surface of the silicon oxide film 7. Thereafter, the output before and after the moisture resistance test (humidity: 85%, temperature: 85 ° C., test time: 5 hours) was measured for each sample of Examples 1 and 2 in which the above aqueous solution was applied. did. Then, normalization was performed using the output of each sample before the moisture resistance test as a reference (“1”). In each sample of Examples 1 and 2, the volume ratios of the fine particles made of ZnO in the silicon oxide film 7 are 7% and 18%, respectively. In each sample of Examples 1 and 2, the average particle diameter of the fine particles made of ZnO contained in the silicon oxide film 7 is 0.02 μm.

  As shown in FIG. 23, in both cases of Examples 1 and 2, if the thickness of the silicon oxide film 7 is 0.01 μm or more, the rate of decrease in the normalized output is 0.01 (1%) or less. Turned out to be. This is because, by setting the thickness of the silicon oxide film 7 to 0.01 μm or more, moisture containing a sodium component has been prevented from entering each semiconductor layer disposed below the silicon oxide film 7. it is conceivable that. Further, comparing Example 1 in which the volume ratio of ZnO particles in the silicon oxide film 7 is 7% and Example 2 in which the volume ratio of ZnO particles in the silicon oxide film 7 is 18%. It has been found that if the thickness of the silicon oxide film 7 is the same, the rate of decrease in the normalized output hardly changes.

  From this result, in order to prevent moisture containing sodium components from entering the semiconductor layers disposed below the silicon oxide film 7, the thickness of the silicon oxide film 7 is set to 0.01 μm or more. It is considered preferable. In this case, even if the volume ratio of the fine particles of ZnO in the silicon oxide film 7 is changed, it is considered that the output characteristics of the photovoltaic device 1 are not affected.

  Next, a photovoltaic device in which a silicon oxide film containing fine particles of ZnO is formed on the light incident side (Example 2), and a photovoltaic device in which no silicon oxide film is formed on the light incident side ( An experiment conducted to examine the difference in moisture resistance reliability from Comparative Example 2) will be described.

  In this experiment, first, three photovoltaic devices 1 of Example 2 described above are connected in series by the tab electrode 22, and the three photovoltaic devices 1 connected in series are arranged horizontally in three rows. Thus, a photovoltaic module was produced. As Comparative Example 2, three photovoltaic devices (not shown) in which a silicon oxide film is not formed are connected in series by a tab electrode, and three photovoltaic devices connected in series are connected to three photovoltaic devices. Photovoltaic modules were fabricated by placing them side by side. Thereafter, for each photovoltaic module of Example 2 and Comparative Example 2, the output before and after the humidity resistance test (humidity: 85%, temperature: 85 ° C., test time: 3000 hours) (average of three rows) Output). Then, normalization was performed using the output of each photovoltaic module before the moisture resistance test as a reference (“1”). In the photovoltaic device 1 of Example 2, the volume ratio of the fine particles made of ZnO in the silicon oxide film 7 is 18%. Moreover, in the photovoltaic device 1 of Example 2, the average particle diameter of the fine particles made of ZnO contained in the silicon oxide film 7 is 0.02 μm. The results are shown in Table 2 below.

  Referring to Table 2 above, the photovoltaic module (Example 2) using the photovoltaic device 1 in which the silicon oxide film 7 containing fine particles of ZnO is formed on the light incident side is more silicon. It was found that the rate of decrease in output after the moisture resistance test was smaller than that of a photovoltaic module (Comparative Example 2) using a photovoltaic device in which no oxide film was formed. Specifically, the normalized output of the photovoltaic module (Example 2) using the photovoltaic device 1 in which the silicon oxide film 7 containing fine particles of ZnO is formed on the light incident side is 98. It was 5%. On the other hand, the normalized output of the photovoltaic module (Comparative Example 2) using the photovoltaic device in which the silicon oxide film was not formed was 96.1%.

  From this result, it was confirmed that the moisture resistance of the photovoltaic device 1 can be improved by forming the silicon oxide film 7 containing fine particles of ZnO on the light incident side of the photovoltaic device 1. .

Na us, the embodiments disclosed herein are, it should be considered and not restrictive in all respects as illustrative. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

For example, in the above you facilities embodiment, as larger material than the etching rate of silicon oxide by the flux, was used ZnO, the present invention is not limited thereto and may be a material other than ZnO. Examples of the material whose etching rate by flux other than ZnO is higher than that of silicon oxide include ITO.

The upper in you facilities embodiment, the surface of the semiconductor layers constituting the photovoltaic device has been described a case flat, the present invention is not limited to this, the semiconductor layers constituting the photovoltaic device at least one Even in the case where the surface has an uneven shape, the same effect as in the above embodiment can be obtained.

Further, in the above you facilities embodiment, the back surface side of the photovoltaic module, but not provided, such as aluminum sheet for improving the moisture resistance, the present invention is not limited to this, on the back surface side of the photovoltaic module In order to improve moisture resistance, an aluminum sheet or the like may be provided on the back side of the photovoltaic module.

Further, in the above you facilities form has been explained as an example a photovoltaic device having a structure i type amorphous silicon layer and p-type amorphous silicon layers on n-type single crystal silicon substrate is formed, the The invention is not limited to this, and can be widely applied to photovoltaic devices having other structures.

Further, in the above you facilities embodiment, as the semiconductor material, silicon is used (Si), the present invention is not limited to this, SiGe, SiGeC, SiC, SiN , SiGeN, SiSn, SiSnN, SiSnO, SiO, Ge, Any semiconductor of GeC and GeN may be used. In this case, these semiconductors may be crystalline or amorphous or microcrystalline containing at least one of hydrogen and fluorine.

Further, in the above you facilities embodiment, as the material constituting the translucent conductive film, was used doped indium oxide (ITO) and Sn, the present invention is not limited to this, Toru made of a material other than ITO film A photoconductive film may be used. For example, a target prepared by mixing and sintering an appropriate amount of at least one of Zn, As, Ca, Cu, F, Ge, Mg, S, Si, and Te as a compound powder in indium oxide powder (In2O3) is used. A translucent conductive film formed in this manner may be used.

Further, in the above you facilities embodiment has formed the amorphous silicon layer by RF plasma CVD method, the present invention is not limited to this, vapor deposition, sputtering, microwave plasma CVD, ECR method, a thermal The amorphous silicon layer may be formed using other methods such as a CVD method and an LPCVD (low pressure CVD) method.

Further, in the above you facilities embodiment, during the sputtering of the ITO film constituting the transparent conductive film, was used Ar gas, the present invention is not limited to this, He, Ne, Kr, other inert gases or Xe It is also possible to use these mixed gases.

Further, in the above you facilities embodiment, the discharge operation at the time of sputtering was carried out using the DC power, the present invention is not limited to this, and pulse modulation DC discharge, RF discharge, VHF discharge, and microwave discharge It may be used.

Further, in the above you facilities embodiment is provided with the silicon oxide film only on the surface side of the photovoltaic device, the present invention is not limited to this, a silicon oxide film is provided on both front and back surfaces of the photovoltaic device May be. Incidentally, as above you facilities embodiment, the case in which the surface protective material made of a glass substrate on the surface side, sodium eluted from the glass substrate constituting the front surface protective member reaches the surface side of the photovoltaic device Therefore, it is necessary to provide a silicon oxide film at least on the surface side of the photovoltaic device. Accordingly, the upper in the you facilities embodiment, even if not provided silicon oxide film on the back surface side of the photovoltaic device, hardly sodium from entering the semiconductor layers constituting the photovoltaic device.

Is a perspective view showing a structure of a photovoltaic device according to implementation embodiments of the present invention. Is a sectional view showing the structure of an optical electromotive force module that by the implementation form shown in FIG. Is an enlarged view of the tab electrodes showed the connected state to the bus bar electrode of the surface-side collecting electrodes of the optical electromotive force device shown in FIG. Is a sectional view for illustrating the manufacturing process of the optical electromotive force module that by the implementation of the invention. It is a sectional view showing a state in which flux is applied to the silicon oxide film of the photovoltaic device according to the actual Example 1. It is a sectional view showing a state in which flux is applied to the silicon oxide film of the photovoltaic device according to the real施例2. It is a sectional view showing a state in which flux is applied to the silicon oxide film of the photovoltaic device according to the real施例3. It is a sectional view showing a state in which flux is applied to the silicon oxide film of the photovoltaic device according to the real施例4. It is a sectional view showing a state in which flux is applied to the silicon oxide film of the photovoltaic device according to the real施例5. 5 is a cross-sectional view showing a state in which a flux is applied on a silicon oxide film of a photovoltaic device according to Comparative Example 1. FIG. Is a cross-sectional view tab electrode to the bus bar electrode of the surface-side collecting electrodes of the photovoltaic device according to the actual Example 1 showed the connected state. Is a cross-sectional view tab electrode to the bus bar electrode of the surface-side collecting electrodes by Real施例2 photovoltaic device showed the connected state. Is a sectional view on the bus bar electrode portion tab electrode showed the connected state of the surface-side collective electrodes by Real施例3 photovoltaic device. Is a cross-sectional view tab electrode to the bus bar electrode of the surface-side collecting electrodes of the photovoltaic device according to the real施例4 showed the connected state. Is a cross-sectional view tab electrode to the bus bar electrode of the surface-side collecting electrodes of the photovoltaic device according to the real施例5 showed the connected state. It is sectional drawing which showed the state by which the tab electrode was connected to the bus-bar electrode part of the surface side collector electrode of the photovoltaic apparatus by the comparative example 1. It is a schematic diagram of the measuring apparatus used when measuring adhesive strength. 6 is a graph showing the relationship between the thickness of a silicon oxide film containing fine particles of ZnO and the normalized spectral sensitivity. 6 is a graph showing the relationship between the thickness of a silicon oxide film containing fine particles of ZnO and the normalized spectral sensitivity. It is the graph which showed the relationship between the average particle diameter of the microparticles | fine-particles which consist of ZnO contained in the silicon oxide film, and the normalized spectral sensitivity. It is the graph which showed the relationship between the average particle diameter of the microparticles | fine-particles which consist of ZnO contained in the silicon oxide film, and the normalized spectral sensitivity. It is the graph which showed the relationship between the thickness of a silicon oxide film, and a normalization curve factor (FF). It is the graph which showed the relationship between the thickness of a silicon oxide film, and the normalization output.

2 n-type single crystal silicon substrate (photoelectric conversion layer, semiconductor layer)
3 i-type amorphous silicon layer (semiconductor layer)
4 p-type amorphous silicon layer (semiconductor layer)
6 Surface side collector (collector)
6a Finger electrode part 6b Bus bar electrode part 7, 47 Silicon oxide film 8 i-type amorphous silicon layer (semiconductor layer)
9 n-type amorphous silicon layer (semiconductor layer)
22, 52 Tab electrode 23 Solder layer (fusion layer)
24 Filler 25 Surface protective material 26 Back surface protective material

Claims (5)

A photovoltaic module comprising a plurality of photovoltaic devices connected by tab electrodes,
The photovoltaic device includes a collector electrode having a finger electrode portion and a bus bar electrode portion formed in a predetermined region on the light incident surface, and a finger electrode portion and a bus bar electrode portion of the collector electrode on the light incident surface. A silicon oxide film formed so as to cover both,
The silicon oxide film contains fine particles made of a material whose etching rate by flux is larger than that of silicon oxide,
The tab electrode is disposed on a first portion of the silicon oxide film located on the upper surface of the bus bar electrode portion of the collector electrode,
In the first portion of the silicon oxide film, the fine particles are etched by the flux, so that a part of the upper surface of the bus bar electrode portion of the collector electrode is exposed,
The photovoltaic module, wherein the bus bar electrode portion of the collector electrode and the tab electrode are connected by a fusion layer through a portion of the silicon oxide film where the fine particles are etched. The photovoltaic module according to claim 1, wherein the fine particles are fine particles made of ZnO. The photovoltaic module according to claim 1 or 2, wherein an average particle size of the fine particles is 0.1 µm or less. The photovoltaic module according to claim 1, wherein the silicon oxide film has a thickness of 0.01 μm or more and 6 μm or less. Forming a plurality of semiconductor layers including a photoelectric conversion layer;
Forming a collector electrode having a finger electrode portion and a bus bar electrode portion on at least a light incident surface of the semiconductor layer;
A coating solution mainly composed of polysilazane containing fine particles made of a material whose etching rate by flux is larger than that of silicon oxide so as to cover both the finger electrode portion and bus bar electrode portion of the collector electrode on the light incident surface. A step of applying
Forming a silicon oxide film containing the fine particles on the light incident surface by curing the coating solution by a heat treatment, and
After the step of forming the silicon oxide film,
A portion of the upper surface of the bus bar electrode portion of the collector electrode is exposed by etching the fine particles by applying the flux on the first portion of the silicon oxide film corresponding to the bus bar electrode portion of the collector electrode. A process of
A method of manufacturing a photovoltaic module, comprising: connecting a bus bar electrode portion of the collector electrode and a tab electrode with a fusion layer through a portion of the silicon oxide film where the fine particles are etched.

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