JP2008305945A - Substrate for thin film solar cell and manufacturing method of the same, and manufacturing method of thin film solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate for thin film solar cell for simply manufacturing at a lower cost a thin film solar cell having excellent dielectric resistance and weather resistance. <P>SOLUTION: The substrate for thin film solar cell is characterized in including a light transmitting insulating underlayer (2) formed in the entire region other than the entire circumferential edge region up to the internal side of the predetermined width from the entire circumferential edge of the light transmitting insulating supporting material (1) on the principal surface of this supporting material. The light transmitting insulating underlayer further includes a transparent electrode layer (3) having the front surface including concave and convex areas formed to cover the entire circumferential region and the light transmitting insulating underlayer of the light transmitting insulating supporting material. Moreover, the transparent electrode layer includes zinc oxide as the principal element. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a thin film solar cell substrate, and more particularly to a thin film solar cell substrate capable of improving the reliability of a thin film solar cell.

  A thin-film solar cell generally includes a transparent electrode layer, a semiconductor photoelectric conversion layer including one or more semiconductor photoelectric conversion units, and a highly reflective back electrode layer, which are sequentially laminated on a light-transmitting light-transmitting insulating support. Is included. Further, in a relatively large area thin film solar cell, laser scribe is performed at each point after the transparent electrode layer is formed, the semiconductor photoelectric conversion layer is formed, and the highly reflective back electrode layer is formed. A plurality of solar cells are connected in series or in parallel on the optical insulating support to be integrated. After the formation of the back electrode layer, the entire surface of the back surface of the thin film solar cell is sealed with a resin sealing material and a protective film or a protective material, thereby completing the thin film solar cell module.

  Since a thin film solar cell module having a relatively large area is generally used outdoors, moisture or the like may enter from the outside and the solar cell may be altered or corroded. Of course, in that case, the pressure resistance and power generation characteristics of the thin-film solar cell module deteriorate. As one of the specific causes of this problem, it is conceivable that moisture penetrates from between the translucent insulating support and the resin sealing material at the peripheral end of the thin film solar cell module. Therefore, it is required to improve the weather resistance and reliability of the thin-film solar cell module by reliably preventing moisture from entering from the peripheral end portion.

From such a viewpoint, in Japanese Patent Application Laid-Open No. 2000-150944 of Patent Document 1, a transparent tin oxide electrode layer, a semiconductor photoelectric conversion layer, and a back electrode layer are separated into a plurality of cell regions by laser scribing on a transparent glass support. In a thin film solar cell module in which the cell regions are deposited and integrated by being electrically connected to each other, a tin oxide electrode layer, a semiconductor photoelectric conversion layer, and a back metal electrode layer in the peripheral region of the glass support It is disclosed that by removing mechanically, a solar cell module can be provided that has excellent dielectric strength after backside sealing and does not cause degradation in power generation characteristics due to corrosion due to environmental influences.
JP 2000-150944 A

  In the method for improving the dielectric strength and weather resistance of the thin-film solar cell module disclosed in Patent Document 1, a tin oxide electrode layer, a semiconductor photoelectric conversion layer, while maintaining the strength of the support in the peripheral region of the glass support, And it is not easy to completely remove the metal electrode layer. This is because the tin oxide electrode layer is formed on the glass support by thermal CVD (chemical vapor deposition) at a relatively high temperature of about 400 to 500 ° C., and the adhesion to the glass support is considerably strong. . That is, if the tin oxide electrode layer is mechanically completely removed in the peripheral region of the glass support, the glass support is damaged in the peripheral region, and the mechanical strength tends to decrease.

  In addition, a tin oxide layer that is widely used as a transparent electrode layer of a thin film solar cell has a feature of high chemical stability, but is not necessarily desirable from the viewpoint of productivity. This is because the tin oxide electrode layer needs to be formed by a high-temperature process of 400 ° C. or more as described above, and it is difficult to remove (process) by a method such as etching.

  In view of the situation in the prior art as described above, the present invention provides a thin film solar cell substrate that can easily and inexpensively manufacture a thin film solar cell excellent in dielectric strength and weather resistance. It is aimed.

  A thin film solar cell substrate according to the present invention is a translucent insulating underlayer formed on one main surface of a translucent insulating support in all regions other than the entire peripheral region from the entire peripheral edge to the inside of a predetermined width. The transparent insulating underlayer has a surface irregularity, and further includes a transparent electrode layer formed so as to cover the entire peripheral region of the transparent insulating support and the transparent insulating underlayer, The transparent electrode layer is characterized by containing zinc oxide as a main component.

  In addition, it is preferable that it is a width of 5 mm or more and 15 mm or less as a whole peripheral area | region of the translucent insulating support body. The light-transmitting insulating base layer may include insulating fine particles having a particle size in the range of 0.05 to 1.0 μm and a binder. The insulating fine particles preferably include at least silicon oxide fine particles, and the binder preferably includes silicon oxide as a main component.

  As a preferable method for manufacturing the above-described thin film solar cell substrate, a mask is provided that covers the entire peripheral region of the translucent insulating support, a translucent insulating base layer is formed in the inner region of the mask, and the mask is formed. The transparent electrode layer can be deposited so as to cover and cover the entire peripheral region of the translucent insulating support and the translucent insulating base layer.

  A tape is attached as the mask, and a light-transmitting insulating base layer can be formed by a dipping method. When the translucent insulating base layer is formed by the dipping method, the antireflection layer can be simultaneously formed in the entire region of the main surface facing one main surface provided with the mask in the translucent insulating support. Note that the translucent insulating base layer may be formed by a roll coating method.

  In the method of manufacturing a thin film solar cell using the above-described thin film solar cell substrate, a semiconductor photoelectric conversion layer and a back electrode layer are sequentially deposited on the transparent electrode layer of the thin film solar cell substrate, and a translucent insulating support is provided. A step of removing the transparent electrode layer, the semiconductor photoelectric conversion layer, and the back electrode layer on the entire peripheral region, and bonding a protective layer so as to cover the back electrode layer and the entire peripheral region of the translucent insulating support. It is preferable.

  The method for manufacturing the thin film solar cell may further include a laser scribing step for dividing the transparent electrode layer, the semiconductor photoelectric conversion layer, and the back electrode layer into a plurality of strip cell regions. Can be electrically connected in series. One or more amorphous semiconductor photoelectric conversion units can also be formed when depositing the semiconductor photoelectric conversion layer. Furthermore, in the deposition of the semiconductor photoelectric conversion layer, one or more amorphous semiconductor photoelectric conversion units and one or more crystalline photoelectric conversion units can be stacked.

  In the thin film solar cell substrate according to the present invention, the entire peripheral area from the entire peripheral edge of one principal surface of the translucent insulating support to the inside of the predetermined width is in direct contact with the zinc oxide electrode layer. That is, in this entire peripheral region, the adhesion strength between the translucent insulating support and the zinc oxide electrode layer is small, and the zinc oxide electrode layer can be removed relatively easily. Therefore, after sequentially depositing the semiconductor photoelectric conversion layer and the back electrode layer on the zinc oxide electrode layer, the zinc oxide electrode layer, the semiconductor photoelectric conversion layer, and the back electrode layer can be easily formed on the entire peripheral region of the translucent insulating support. The protective layer can be bonded and sealed so as to cover the back electrode layer and the entire peripheral region of the translucent insulating support. As a result, it is possible to provide a thin-film solar cell module that has excellent dielectric strength characteristics and does not cause degradation in power generation characteristics due to corrosion from the peripheral edge.

  Further, the transparent electrode layer of zinc oxide can be formed at a low temperature of 200 ° C. or lower, and the thin film solar cell can be manufactured at a lower cost than when a transparent electrode layer of tin oxide formed at a temperature of 400 ° C. or higher is used. A battery substrate and a thin-film solar battery including the same can be manufactured.

  1 and 2 illustrate a method for manufacturing a thin film solar cell substrate according to an embodiment of the present invention. In the drawings of the present application, dimensional relationships such as length, width, and thickness are appropriately changed for clarity and simplification of the drawings, and do not represent actual dimensional relationships. In particular, the thickness is shown significantly enlarged compared to the length and width. In the drawings of the present application, the same reference numerals represent the same or corresponding parts.

  In FIG. 1, the entire peripheral area from the entire peripheral edge of the upper surface of the translucent insulating support 1 to the inside of a predetermined width is covered with a mask 11. In FIG. 1, the mask 11 is shown only in a partial region. In the region surrounded by the mask 11, the light-transmitting insulating base layer 2 is formed. Then, after the light-transmissive insulating base layer 2 is formed, the mask 11 is removed.

  In addition, it is preferable that the whole peripheral area | region where the translucent insulating base layer 2 is covered with the mask 11 has a width | variety of 5 mm or more and 15 mm or less. This is because, as will be understood from the following description, if the width of the entire peripheral region is less than 5 mm, the peripheral sealing of the thin film solar cell may be insufficient, and conversely, the width should be larger than 15 mm. This is because it is not preferable from the viewpoint of reducing the effective power generation area of the thin-film solar cell.

As the translucent insulating support 1, a plate-like member or a sheet-like member made of glass or transparent resin can be used. In particular, a soda-lime glass plate containing SiO ₂ , Na ₂ O and CaO as main components and having both smooth main surfaces has high transparency and insulation, and a large-area plate can be obtained at low cost. The insulating insulating support 1 is preferable.

  As the mask 11, for example, a tape can be simply attached. As such a mask tape 11, a general heat-resistant tape having heat resistance equal to or higher than the heating and drying temperature at the time of forming the translucent insulating base layer 2 can be used, for example, Teflon (registered trademark) tape, polyimide tape. Various tapes such as an aluminum foil tape can be used.

The translucent insulating base layer 2 preferably includes fine particles made of at least silicon oxide (SiO ₂ ). This is because the refractive index of SiO ₂ is lower than that of the zinc oxide electrode layer 3 (see FIG. 2) and has a value close to that of the glass support 1. Further, SiO ₂ has high transparency and is suitable as a material used on the light incident side of the solar cell. Further, the light-transmitting insulating base layer 2 is made of titanium oxide (TiO ₂ ), aluminum oxide (Al ₂ O ₃ ), indium tin oxide (ITO), zirconium oxide in addition to SiO ₂ for the purpose of adjusting the refractive index. Fine particles such as (ZrO ₂ ) or magnesium fluoride (MgF ₂ ) may be included.

The method for forming the light-transmitting insulating base layer 2 containing fine particles as described above on the light-transmitting insulating support 1 is not particularly limited, but a method of applying fine particles together with a binder material containing a solvent is preferable. As the binder material that plays a role in improving the adhesion strength between the fine particles and between the fine particles and the translucent insulating support 1, the deposition condition (especially temperature) of the semiconductor layer 4 (see FIGS. 3 and 4). In consideration of durability and reliability in long-term use, inorganic materials are preferable. Specifically, metal oxides such as silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, and tantalum oxide can be used. In particular, when SiO ₂ fine particles are deposited on the glass support 1, the silicon oxide binder material, which also contains silicon as a main component, produces strong adhesion due to the formation of silicide bonds, and its transparency is good and refracted. The rate is also preferable because it is close to the glass support 1 and SiO ₂ fine particles.

  As a method for applying the coating liquid containing the fine particles and the binder material onto the translucent insulating support 1, a dipping method, a spin coating method, a bar coating method, a spray method, a die coating method, a roll coating method, and a flow coating method In order to uniformly form the light-transmitting insulating base layer 2 containing fine particles densely, a roll coating method is preferable. On the other hand, when the transparent insulating base layer 2 is formed by the dipping method, an antireflection layer (not shown in FIG. 1) can be simultaneously formed on the entire lower surface of the transparent insulating support 1. (See symbol 7 in FIG. 4).

  When the application of the coating liquid is completed, the coating liquid film is immediately heated and dried. Since the translucent insulating base layer 2 thus formed contains fine particles, it has surface unevenness, the shape of the protrusions is a curved surface, and the unevenness of the unevenness is relatively uniform. Therefore, in the zinc oxide electrode layer 3, the semiconductor layer 4, and the back electrode layer 5 (see FIG. 3) to be formed later, an electrical short circuit is caused due to a sharp convex portion on the surface of the translucent insulating base layer 2. There is nothing. The surface unevenness of the translucent insulating base layer 2 can act to scatter incident light, and can also act to enhance the bondability with the zinc oxide electrode layer 3 deposited thereon.

  In addition, when using a glass plate as the translucent insulating support 1, the effect of the base layer 2 as an alkali barrier film that prevents alkali metal from glass from entering the zinc oxide electrode layer 3 and the semiconductor layer 4 is enhanced. Therefore, in order to prevent color unevenness due to light interference that occurs when the thickness of the transparent zinc oxide electrode layer 3 is not constant, a plurality of layers having different refractive indexes between the base layer 2 and the zinc oxide electrode layer 3 A thin film in combination with may be interposed.

  After the formation of the translucent insulating base layer 2, the mask tape 11 is peeled off and removed. Then, as shown in FIG. 2, the zinc oxide electrode layer is formed so as to cover the entire peripheral region covered with the mask tape 11 on the translucent insulating support 1 and the translucent insulating base layer 2. 3 is deposited.

  In the zinc oxide electrode layer 3, fine surface irregularities are produced by adjusting the deposition conditions, thereby obtaining an effect of increasing the scattering of incident light. The height difference of the surface irregularities is about 0.03 to 0.3 μm, and the haze ratio of the glass support 1, the underlayer 2, and the zinc oxide electrode layer 3 is about 5 to 30%. The sheet resistance of the zinc oxide electrode layer 3 is set to about 5 to 20Ω / □.

  The zinc oxide electrode layer 3 can be formed using a method such as CVD, sputtering, or vapor deposition. In particular, the zinc oxide electrode layer 3 is formed by the CVD method from the viewpoint that the deposition of the zinc oxide layer having fine surface irregularities that causes the light confinement effect of the well-known thin film solar cell is possible at a low temperature of 200 ° C. or less by the CVD method. It is preferable.

  More specifically, the zinc oxide electrode layer 3 is formed by a CVD method under reduced pressure conditions using a source gas containing a dopant composed of organic zinc, an oxidizing agent, and a group III element at a substrate temperature of 200 ° C. or lower. Can be done. In this case, it is preferable from the viewpoint of obtaining the light confinement effect of the thin-film solar cell that the gap between the ridges and valleys of the surface unevenness of the zinc oxide electrode layer 3 is approximately 50 to 500 nm and the height difference is approximately 20 to 200 nm. Note that the above substrate temperature is measured as the temperature of the substrate surface in contact with the heating unit in the film forming apparatus.

  The average thickness of the zinc oxide electrode layer 3 is preferably 0.5 to 5 μm, and more preferably 1 to 3 μm. This is because if the zinc oxide electrode layer 3 is too thin, it is difficult to sufficiently impart surface irregularities that contribute to the light confinement effect, and it becomes difficult to obtain the necessary conductivity as the electrode layer. . Conversely, if the zinc oxide electrode layer 3 is too thick, the amount of light reaching the semiconductor layer 4 is reduced due to its own light absorption and the photoelectric conversion rate is reduced. Moreover, when the zinc oxide electrode layer 3 is too thick, the film formation cost increases due to the increase in the film formation time.

  In one embodiment of the present invention as described above, a thin film solar cell substrate as shown in FIG. 2 can be obtained simply and at low cost. Then, using such a thin-film solar cell substrate, a thin-film solar cell excellent in withstand voltage and weather resistance is produced, for example, as illustrated in the schematic cross-sectional view of FIG. 3 or FIG. obtain. 4 is different from FIG. 3 only in that an antireflection layer 7 is formed on the lower surface of the translucent insulating support 1.

  FIG. 3 shows a state immediately before the integrated thin film solar cell formed using the thin film solar cell substrate of FIG. As can be understood from FIG. 3, in the deposited zinc oxide electrode layer 3, a separation groove 301 is formed by laser processing so as to be separated into a plurality of strip-shaped regions corresponding to a plurality of solar cells to be integrated. Is done. For this laser processing, for example, the fundamental wave (wavelength 1064 nm) of an Nd-YAG laser can be used.

  After the separation groove 301 is formed, the semiconductor layer 4 that performs a photoelectric conversion action is formed on the zinc oxide electrode layer 3. The semiconductor layer 4 may be a single photoelectric conversion unit including a pin junction, for example, or may be a laminate of a plurality of units. As the semiconductor layer 4, it is desired to be able to absorb the main wavelength range (400 to 1200 nm) of sunlight, and for example, a crystalline silicon-based unit can be preferably used. Note that the “silicon-based” material includes not only silicon but also silicon carbide or silicon germanium containing 50% or more of silicon.

  The deposited semiconductor layer 4 is divided into a plurality of strip-like regions by connection grooves 401 formed by laser processing, as in the case of the zinc oxide electrode layer 3. For this laser processing, for example, the second harmonic (wavelength 532 nm) of an Nd-YVO4 laser can be used. If a laser beam having such a wavelength is used, the zinc oxide electrode layer 3 absorbs less and damage is reduced, and the semiconductor layer 4 absorbs large and enables efficient laser processing. Chemical etching or mechanical processing can also be used for processing the semiconductor layer 4.

  As suggested above, in the present invention, an amorphous silicon photoelectric conversion unit and a crystalline silicon photoelectric conversion unit are sequentially stacked as the semiconductor layer 4 to manufacture a tandem thin film solar cell. It goes without saying that it is possible. In this case, the amorphous silicon-based photoelectric conversion layer is sensitive to light having a wavelength of about 360 to 800 nm, and the crystalline silicon-based photoelectric conversion layer 42 photoelectrically converts light having a longer wavelength up to about 1200 nm. Is possible. Therefore, by arranging the amorphous silicon photoelectric conversion layer and the crystalline silicon photoelectric conversion layer in this order from the light incident side, it is possible to effectively use incident light in a wider wavelength range.

After the connection groove 401 is formed, the back electrode layer 5 is formed on the semiconductor layer 4. As the back electrode layer 5, it is preferable to form at least one metal layer containing at least one of Al, Ag, Au, Cu, Pt, and Cr by sputtering or vapor deposition. A conductive oxide layer (not shown) such as ITO, SnO ₂ , or ZnO may be formed between the semiconductor layer 4 and the back electrode layer 5. This conductive oxide layer not only enhances the adhesion between the semiconductor layer 4 and the back electrode layer 5, but also increases the light reflectivity of the back electrode layer 5, and the metal element from the back electrode layer 5 becomes a semiconductor. It can also serve to prevent diffusion into layer 4.

  The back electrode layer 5 is laser processed by the same method as that for the semiconductor layer 4. More specifically, a laser beam is incident from the translucent insulating support 1 side, the semiconductor layer 4 is locally sublimated, and at the same time, the back electrode layer 5 is locally blown off, so that a plurality of parallel separation grooves 501 are obtained. Form.

  Thereafter, the zinc oxide electrode layer 3, the semiconductor layer 4, and the back electrode layer 5 are removed by a mechanical method or etching in the entire peripheral region covered with the mask 11 on the translucent insulating support 1. At that time, since the bonding force of the zinc oxide electrode layer 3 to the translucent insulating support 1 is weak, the zinc oxide electrode layer 3, the semiconductor layer 4, and the back electrode layer 5 in the entire peripheral region of the translucent insulating support 1. Can be easily removed.

  After the entire peripheral region of the translucent insulating support 1 is thus exposed, the back surface side of the integrated thin film solar cell is sealed with the organic protective layer 62 via the sealing resin layer 61. At this time, since the translucent insulating support 1 is exposed in the entire peripheral area, the sealing resin layer 61 and the organic protective layer 62 are in direct contact with the translucent insulating support 1 in the entire peripheral area. (Note that the thickness is greatly enlarged in the drawing: the total thickness from the light-transmitting insulating base layer 2 to the back electrode layer 5 is at most several μm). Therefore, in the completed thin film solar cell, it is possible to reliably prevent moisture and the like from entering the inside from the peripheral edge portion to significantly impair the power generation performance.

  Of course, as the sealing resin layer 61, a resin capable of favorably bonding the organic protective layer 62 on the peripheral region of the translucent insulating support 1 and the back electrode layer 5 is used. As such a resin, for example, EVA (ethylene vinyl acetate copolymer), PVB (polyvinyl butyral), PIB (polyisobutylene), and a silicone resin can be used.

  As the organic protective layer 62, an insulating film excellent in moisture resistance and water resistance such as a fluororesin film such as a polyvinyl fluoride film (for example, Tedlar film (registered trademark)) or a PET (polyethylene terephthalate) film is used. Used. The organic protective layer 62 may be a single type of film or may have a laminated structure including a plurality of types of films. The organic protective layer 62 may have a structure in which a metal foil such as aluminum is sandwiched between resin films. Since the metal foil such as the aluminum foil has a function of improving moisture resistance and water resistance, the organic protective layer 62 including the metal foil can more effectively protect the thin film solar cell from moisture. The sealing resin layer 61 and the organic protective layer 62 as described above can be simultaneously bonded to the back surface side of the thin film solar cell by a vacuum laminating method.

  As more specific examples of embodiments of the present invention as described above, several examples are described below along with comparative examples.

Example 1
1 to 3 can also be referred to regarding the method of manufacturing the integrated amorphous silicon thin film solar cell according to the first embodiment. In Example 1, a white glass support of 360 mm × 465 mm × 4 mm was prepared as the translucent insulating support 1 first.

A mask 11 of an aluminum foil tape was attached so as to cover the entire peripheral area from the entire peripheral edge of the white glass support 1 to the inner side with a width of 5 mm. In the inner region of the mask 11, an SiO ₂ film having an average thickness of 100 nm containing SiO ₂ particles was formed as a translucent insulating base layer 2 on the white glass support 1 by a roll coating method.

  Thereafter, the mask 11 was removed, and a zinc oxide electrode layer 3 having a fine surface uneven structure was deposited by a CVD method so as to cover the entire peripheral region of the white glass support 1 and the translucent insulating base layer 2. More specifically, the pressure was set to 133 Pa (1 Torr) and the substrate temperature was adjusted to 150 ° C. in the film formation chamber. Into the film formation chamber, hydrogen was introduced at a flow rate of 1000 sccm, diborane diluted to 5000 ppm with hydrogen at 500 sccm, water at 100 sccm, and diethylzinc at 50 sccm, and the zinc oxide electrode layer 3 was deposited to a thickness of 1.5 μm. did. Thus, the thin film solar cell substrate in Example 1 was produced.

  With respect to the zinc oxide electrode layer 3 deposited in Example 1, the sheet resistance, haze ratio, and transmittance were measured using a resistance meter, a haze meter (NDH5000W type, manufactured by Nippon Denshoku Co., Ltd.) and a spectrophotometer, respectively. It was. As a result, the resistivity was 9Ω / □, the haze ratio measured with a C light source from the zinc oxide electrode layer 3 side was 20%, and the transmittance for light with a wavelength of 1000 nm was 81%.

  In such a zinc oxide electrode layer 3, by forming a plurality of parallel separation grooves 301 by laser processing using a fundamental wave (wavelength 1064 nm) of an Nd-YAG laser, it corresponds to a plurality of integrated photovoltaic cells. A plurality of strip-like regions were separated.

  Next, an amorphous silicon photoelectric conversion unit having a thickness of about 300 nm was formed as a semiconductor layer 4 on the zinc oxide electrode layer 3 by a plasma CVD method. This amorphous silicon photoelectric conversion unit includes a p-type microcrystalline silicon layer, a p-type amorphous silicon carbide layer, an i-type amorphous silicon layer, and an n-type layer which are sequentially stacked.

The p-type microcrystalline silicon layer has a thickness of 15 nm by introducing silane, diborane, and hydrogen into the deposition chamber, setting the pressure to 350 Pa, and applying high frequency power for plasma excitation at a density of 150 mW / cm ² . Deposited in thickness. By forming such a p-type microcrystalline silicon layer on the zinc oxide electrode layer 3, the ohmic contact characteristics between the p-type amorphous silicon carbide layer and the zinc oxide electrode layer 3 are improved, and the curvature of the solar cell is improved. Factors can be improved. In order to improve the bondability between the zinc oxide electrode layer 3 and the p-type microcrystalline silicon layer, hydrogen is used so that the surface of the zinc oxide electrode layer 3 is cleaned before the p-type microcrystalline silicon layer is formed. Plasma treatment may be performed with argon, nitrogen, or the like.

The p-type amorphous silicon carbide layer is formed by introducing silane, diborane, hydrogen, and methane into the deposition chamber, setting the pressure to 133 Pa, and applying high frequency power for plasma excitation at a density of 170 mW / cm ² . Deposited to a thickness of 10 nm. Subsequently, silane and hydrogen are introduced into the film formation chamber, the pressure is set to 50 Pa, and high frequency power for plasma excitation is applied at a density of 120 mW / cm ² , whereby the i-type amorphous silicon layer has a thickness of 300 nm. It was deposited. Further, silane, phosphine, and hydrogen were introduced into the film formation chamber, the pressure was set to about 350 Pa, and an n-type silicon layer was deposited to a thickness of about 10 nm.

  The support 1 laminated up to the semiconductor layer 4 is introduced into a sputtering chamber, and a zinc oxide layer (not shown) doped with aluminum (Al) by using argon as a sputtering gas under RF (radio frequency) discharge. Was deposited to a thickness of 30 nm.

  Thereafter, the support 1 is once taken out from the sputtering chamber, and the semiconductor layer 4 and the zinc oxide layer having a thickness of 30 nm thereon are formed by laser processing using the second harmonic (wavelength 532 nm) of the Nd-YAG laser. It was divided into a plurality of strip-shaped regions by the connection grooves 401.

  The support 1 having the connection groove 401 formed therein was again introduced into the sputtering chamber, and the back electrode layer 5 was formed. As the back electrode layer 5, a zinc oxide layer and a silver layer were sequentially laminated. At this time, a zinc oxide layer doped with aluminum (Al) was deposited to a thickness of 60 nm by using argon as a sputtering gas under RF discharge. A silver layer having a thickness of 200 nm was formed on the zinc oxide layer.

  Thereafter, in order to separate the back electrode layer 5 and the semiconductor layer 4 corresponding to the plurality of cells, a plurality of separation grooves 501 were formed by laser processing using a second harmonic (wavelength: 532 nm) of an Nd-YAG laser.

  After the plurality of cells connected in series is formed in this way, the zinc oxide electrode is formed in the entire peripheral area (area covered by the mask 11) from the entire peripheral edge of the white glass support 1 to the inside of the width of 5 mm. Layer 3, semiconductor layer 4, and back electrode layer 5 were removed by mechanical polishing.

  Finally, an EVA sheet is placed on the back electrode layer 5 as the sealing resin layer 61, and a black fluororesin-based sheet (Tedlar (registered trademark)) is placed thereon as the organic protective layer 62. Sealing was performed. At this time, the sealing resin layer 61 and the organic protective layer 62 are not only bonded to the back surface of the back electrode layer 5 but also on the entire peripheral region covered with the mask 11 on the translucent insulating support 1. Join. That is, the thin film solar cell of FIG. 3 is reliably sealed not only on the back surface but also on the entire peripheral region.

When the output characteristics were measured by irradiating AM1.5 light with an intensity of 100 mW / cm ² to the integrated amorphous silicon thin film photoelectric solar cell of Example 1 obtained in this way, 1 in a plurality of integrated cells. The open circuit voltage per cell was 0.90 V, the short circuit current density was 14.7 mA / cm ² , the fill factor was 70.2%, and the conversion efficiency was 9.2%.

Furthermore, in order to carry out the reliability test of the integrated amorphous silicon thin film solar cell of Example 1, based on JIS standards, atmospheric pressure, air atmosphere, temperature 85 ° C., and humidity 85% RH (relative The output characteristics of the solar cell after being left open in an oven maintained at (humidity) for 1000 hours were evaluated. As a result, the open circuit voltage per cell is 0.90 V, the short-circuit current density is 14.7 mA / cm ² , the fill factor is 70.3%, and the conversion efficiency is 9.2%. There was little change.

(Comparative Example 1)
Also in Comparative Example 1, an integrated thin film solar cell similar to that in Example 1 was produced. That is, the integrated amorphous silicon thin film solar cell of Comparative Example 1 was different from Example 1 only in that the mask 11 was not applied in the manufacturing process.

When the integrated amorphous silicon thin film solar cell obtained in Comparative Example 1 was irradiated with AM 1.5 light at an intensity of 100 mW / cm ² and the output characteristics were measured, the open circuit voltage per cell was 0. The short circuit current density was 14.6 mA / cm ² , the fill factor was 69.0%, and the conversion efficiency was 8.9%.

Furthermore, the output characteristics of the integrated amorphous silicon thin film solar cell of Comparative Example 1 were also evaluated after a reliability test was performed according to the same JIS standard as in Example 1. As a result, in the integrated amorphous silicon thin film solar cell of Comparative Example 1, the open-circuit voltage per cell was 0.83 V, the short-circuit current density was 13.8 mA / cm ² , the fill factor was 62.5%, The conversion efficiency was 7.1%, and the output characteristics were greatly deteriorated. This is because the underlying layer 2 was also interposed between the entire peripheral region of the translucent insulating support 1 and the zinc oxide electrode layer 3, so that the back electrode layer was formed from the zinc oxide electrode layer 3 in the entire peripheral region. Up to 5 cannot be sufficiently removed by the mechanical polishing method, and it is considered that the power generation characteristics deteriorated due to corrosion occurring in the peripheral portion and the inside of the solar cell of Comparative Example 1 in the process of the reliability test.

(Example 2)
4 is a schematic cross-sectional view showing an integrated thin-film solar cell according to Example 2. FIG. The integrated thin film solar cell of Example 2 was also produced in the same manner as in Example 1. That is, the integrated amorphous silicon thin film solar cell of Example 2 was different from Example 1 in the manufacturing process only in the following two points (A) and (B).

  (A): A polyimide tape is applied so as to cover the entire peripheral area from the entire peripheral edge of the white sheet glass support 1 to the inner side with a width of 8 mm, and later, the zinc oxide electrode layer 3 within the entire peripheral area with the width of 8 mm. To the back electrode layer 5 were removed by mechanical polishing.

(B): The SiO ₂ underlayer 2 was formed by the dipping method, and at the same time, the SiO ₂ antireflection film 7 was also formed on the lower surface of the white glass support 1.

When the integrated amorphous silicon thin film solar cell obtained in Example 2 was irradiated with AM 1.5 light at an intensity of 100 mW / cm ² and the output characteristics were measured, the open circuit voltage per cell was It was 0.90 V, the short-circuit current density was 15.3 mA / cm ² , the fill factor was 70.4%, and the conversion efficiency was 9.6%.

In addition, compared with the conversion efficiency of 9.2% in the case of Example 1, the conversion efficiency is improved to 9.6% in the case of this Example 2. The reason is that SiO 2 is formed on the lower surface of the white glass support 1. ₂ Probably because the antireflection film 7 was formed.

Further, for the integrated amorphous silicon thin film solar cell of Example 2, the output characteristics of the solar cell after performing a reliability test according to the same JIS standard as in Example 1 were evaluated. As a result, in the integrated amorphous silicon thin film solar cell of Example 2, the open-circuit voltage per cell was 0.90 V, the short-circuit current density was 15.3 mA / cm ² , the fill factor was 70.5%, and The conversion efficiency was 9.7%, and there was almost no change in the output characteristics.

(Example 3)
FIG. 4 can also be referred to regarding the method of manufacturing the integrated tandem thin film solar cell according to Example 3. That is, the integrated amorphous silicon thin film solar cell of Example 3 was different from Example 2 in the manufacturing process only in the following two points (C) and (D).

  (C): An aluminum foil tape is applied so as to cover the entire peripheral area from the entire peripheral edge of the white glass support 1 to the inner side of 10 mm in width, and later, the zinc oxide electrode layer in the entire peripheral area of the width 10 mm 3 to the back electrode layer 5 were removed by mechanical polishing.

  (D): As the semiconductor layer 4, not only an amorphous silicon thin film photoelectric conversion unit but also a crystalline silicon thin film photoelectric conversion unit was laminated thereon.

More specifically, as the semiconductor layer 4 in Example 3, a crystalline silicon photoelectric conversion unit was further formed on the amorphous silicon photoelectric conversion unit by a plasma CVD method. The crystalline silicon photoelectric conversion unit includes a p-type silicon layer, an i-type crystalline silicon layer, and an n-type silicon layer. This p-type silicon layer is deposited to a thickness of 15 nm by introducing silane, diborane and hydrogen into the CVD chamber and applying high frequency power for plasma excitation at a density of 150 mW / cm ² under a pressure of 400 Pa. It was. Subsequently, by introducing silane and hydrogen into the CVD chamber and applying high frequency power for plasma excitation at a density of 150 mW / cm ² under a pressure of 850 Pa, an i-type crystalline silicon layer having a thickness of 1.4 μm is deposited. It was done. Furthermore, silane, phosphine, and hydrogen were introduced into the CVD chamber, and an n-type layer was deposited to a thickness of about 15 nm under a pressure of 350 Pa. Thus, in the semiconductor layer 4, the amorphous silicon photoelectric conversion unit and the crystalline silicon photoelectric conversion unit were sequentially stacked.

  Thereafter, also in Example 3, the back electrode layer 5 and the separation groove 501 are formed in the same manner as in Example 1, and from the zinc oxide electrode layer 3 within the entire peripheral area of width 10 mm on the white glass support 1. After removing up to the back electrode layer 5 by mechanical polishing, the back surface was sealed with a sealing resin layer 61 and an organic protective layer 62 thereon.

The integrated tandem thin film solar cell of Example 3 thus obtained was irradiated with AM 1.5 light at an intensity of 100 mW / cm ² and the output characteristics were measured. The open-circuit voltage per cell was 1.36 V. The short-circuit current density was 12.7 mA / cm ² , the fill factor was 72.8%, and the conversion efficiency was 12.5%.

  Further, for the integrated tandem thin film solar cell of Example 3, the output characteristics of the solar cell were evaluated after performing a reliability test according to the same JIS standard as in Example 1. As a result, in the integrated tandem thin film solar cell of Example 3, the open circuit voltage per cell was 1.36 V, the short circuit current density was 12.7 mA / cm2, the fill factor was 73.0%, and the conversion efficiency was 12 The output characteristics were almost unchanged.

(Comparative Example 2)
Also in Comparative Example 2, an integrated thin film solar cell similar to that in Example 3 was produced. That is, the integrated amorphous silicon thin film solar cell of Comparative Example 2 was different from Example 3 only in that the mask 11 was not applied in the manufacturing process.

The integrated tandem thin film solar cell obtained in Comparative Example 2 was irradiated with AM1.5 light at an intensity of 100 mW / cm ² and the output characteristics were measured. As a result, the output characteristics were almost the same as those of the solar cell of Example 3. The output characteristics are shown. However, in the solar cell of Comparative Example 2 after performing the reliability test according to the same JIS standard as in Example 3, the open-circuit voltage per cell is 1.29 V and the short-circuit current density is 11.8 mA / cm. ^{2. The} fill factor was 65.8%, and the conversion efficiency was 10.0%, and the output characteristics were greatly reduced. This is thought to be due to the occurrence of corrosion at the periphery and the inside of the solar cell of Comparative Example 2 in the process of the reliability test, resulting in a decrease in power generation characteristics.

  As described above, according to the present invention, it is possible to provide a thin film solar cell substrate that can easily and inexpensively manufacture a thin film solar cell excellent in withstand voltage and weather resistance.

It is typical sectional drawing for demonstrating an example of the manufacturing method of the board | substrate for thin film solar cells by this invention. It is typical sectional drawing which shows an example of the board | substrate for thin film solar cells completed after the process of FIG. It is typical sectional drawing which shows an example of the integrated thin film solar cell produced using the board | substrate for thin film solar cells by this invention. It is typical sectional drawing which shows the other example of the integrated thin film solar cell produced using the board | substrate for thin film solar cells by this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Translucent insulation support body, 2 Translucent insulation base layer, 3 Zinc oxide electrode layer, 4 Semiconductor photoelectric conversion layer, 5 Back surface electrode layer, 7 Antireflection layer, 11 Mask tape, 61 Sealing resin layer, 62 Organic Protective layer, 301 transparent electrode layer separation groove, 401 connection groove, 501 back electrode layer separation groove.

Claims (12)

Including a translucent insulating underlayer formed on the main surface of the translucent insulating support in all regions other than the entire peripheral region from the entire peripheral edge to the inside of the predetermined width;
The translucent insulating base layer has surface irregularities,
A transparent electrode layer formed so as to cover the entire peripheral region of the translucent insulating support and the translucent insulating base layer;
The transparent electrode layer contains zinc oxide as a main component.   2. The thin film solar cell substrate according to claim 1, wherein the entire peripheral edge region of the translucent insulating support has a width of 5 mm or more and 15 mm or less.   3. The thin film solar cell substrate according to claim 1, wherein the light-transmitting insulating base layer includes insulating fine particles having a particle size in a range of 0.05 to 1.0 μm and a binder.   4. The thin film solar cell substrate according to claim 3, wherein the insulating fine particles include at least silicon oxide fine particles, and the binder includes silicon oxide as a main component. A method for producing a thin-film solar cell substrate according to claim 1,
Providing a mask covering the entire peripheral area of the translucent insulating support;
Forming the translucent insulating underlayer in an inner region of the mask;
Removing the mask,
A method for producing a substrate for a thin-film solar cell, comprising depositing the transparent electrode layer so as to cover the entire peripheral area of the translucent insulating support and the translucent insulating base layer.   6. The method for manufacturing a thin film solar cell substrate according to claim 5, wherein a tape is attached as the mask, and the light-transmitting insulating base layer is formed by a dipping method.   The translucent insulating base layer is formed by the dipping method, and at the same time, an antireflection layer is formed in the entire area of the main surface facing the one main surface of the translucent insulating support. The manufacturing method of the board | substrate for thin film solar cells of Claim 6 to do.   6. The method of manufacturing a thin film solar cell substrate according to claim 5, wherein the translucent insulating base layer is formed by a roll coating method. A method for producing a thin film solar cell using the thin film solar cell substrate according to claim 1,
A semiconductor photoelectric conversion layer and a back electrode layer are sequentially deposited on the transparent electrode layer of the thin film solar cell substrate,
Removing the transparent electrode layer, the semiconductor photoelectric conversion layer, and the back electrode layer on the entire peripheral region of the translucent insulating support;
A method of manufacturing a thin-film solar cell, comprising a step of bonding a protective layer so as to cover the back electrode layer and the entire peripheral region of the translucent insulating support.   It further includes a laser scribing step for dividing the transparent electrode layer, the semiconductor photoelectric conversion layer, and the back electrode layer into a plurality of strip cell regions, and the plurality of strip cell regions are electrically connected in series. The method for producing a thin-film solar cell according to claim 9.   The method for manufacturing a thin-film solar cell according to claim 9 or 10, wherein in the deposition of the semiconductor photoelectric conversion layer, one or more amorphous semiconductor photoelectric conversion units are formed.   The thin-film solar cell according to claim 9 or 10, wherein in the deposition of the semiconductor photoelectric conversion layer, one or more amorphous semiconductor photoelectric conversion units and one or more crystalline photoelectric conversion units are stacked. Method.

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