JP2013247165A - Thin-film solar battery module and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin-film solar battery module in which management of a manufacturing process is easily performed, and which can achieve superior power generation characteristics with satisfactory reproducibility.SOLUTION: The thin-film solar battery module has a plurality of thin-film solar cells including a surface transparent conductive film, a photoelectric conversion layer formed of a semiconductor layer and a backside metal electrode laminated in this order on a translucent insulating substrate, and has the plurality of the thin-film solar cells electrically connected in series by connecting the backside metal electrode of one of the adjacent thin-film solar cells to the surface transparent conductive film of the other thin-film solar cell. The thin-film solar battery module also has an external lamination region having the same lamination structure as that of the thin-film solar cell formed in a flat region outside a formation region of the thin-film solar cells on the translucent insulating substrate, and has an inspection region in a part of the external lamination region, which is isolated from the other region in the external lamination region by an isolation groove that reaches the translucent insulating substrate from the top face of the backside metal electrode.

Description

  The present invention relates to a thin film solar cell module and a method for manufacturing the same.

  In thin-film solar cell modules, a technique has been developed in which transparent electrode films, semiconductor layers, and the like are separated by laser scribing, and solar cells electrically connected in series are collectively manufactured on a large-area substrate (for example, , See Patent Document 1).

  In addition, in order to increase the light utilization efficiency in the thin-film solar cell, there is a technique for increasing the optical path length inside the power generation layer by scattering the light by providing an uneven shape on the light incident side glass substrate or transparent conductive film. It is used. As a method for forming such a concavo-convex shape, for example, it has been devised to form a fine concavo-convex shape by subjecting a glass substrate to a sand blast treatment or a plasma treatment and then a wet etching treatment (for example, a patent Reference 2).

  In addition, as a method for forming the uneven shape, it has been proposed to form a transparent conductive film made of an oxide on a flat glass substrate and form the uneven shape on the surface of the transparent conductive film by etching (for example, And Patent Document 3).

  In addition, a thin film solar cell has been proposed in which a layer thickness measurement site having a small unevenness is formed on a part of a support having an uneven surface. It has been shown that the layer thickness measurement site is provided in a photoelectric conversion region or a non-photoelectric conversion region directly below the current collecting electrode (see, for example, Patent Document 4).

Japanese Patent No. 3436858 JP 2003-69059 A Japanese Patent No. 4193960 International Publication No. 2010/101116

  However, in the conventional thin film solar cell module, the information obtained by the inspection of the final product is the output characteristics of the solar cell. That is, although it was possible to know the film thickness by inspection in the middle of the manufacturing process, it was not easy to know the variation in the machining process and the dependence of the electrical characteristics on the machining conditions. For this reason, in the inspection of the final product, there is a problem that thin film solar cell modules having inferior power generation characteristics are mixed, resulting in a decrease in yield.

  The present invention has been made in view of the above, and it is possible to easily manage a manufacturing process and obtain a thin film solar cell module capable of realizing good power generation characteristics with high reproducibility and a method for manufacturing the same. Objective.

  In order to solve the above-described problems and achieve the object, a thin-film solar cell module according to the present invention comprises a light-transmitting insulating substrate, a photoelectric conversion layer composed of a surface transparent conductive film and a semiconductor layer, and a back metal electrode. A plurality of thin-film solar cells included in this order are provided, and the back surface metal electrode of one of the thin-film solar cells among the adjacent thin-film solar cells and the surface transparent conductive film of the other thin-film solar cell are connected A thin film solar cell module in which the plurality of thin film solar cells are electrically connected in series, and the thin film solar cell is formed on a flat region outside the formation region of the thin film solar cell on the translucent insulating substrate. The outer stacked region having the same stacked structure as the battery cell is formed, and the outer product is formed in a part of the outer stacked region by a separation groove that reaches the translucent insulating substrate from the upper surface of the back surface metal electrode. Providing the examination region isolated from other regions in the region, characterized by.

  According to the present invention, it is possible to easily manage the manufacturing process, and it is possible to obtain a thin film solar cell module having good power generation characteristics with good reproducibility.

FIG. 1 is a plan view showing a schematic configuration of the thin-film solar cell module according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view showing a schematic configuration of the thin-film solar cell module according to Embodiment 1 of the present invention, and is a cross-sectional view taken along line A-A ′ of FIG. 1. FIG. 3 is a flowchart showing manufacturing steps of the thin film solar cell module. FIG. 4 is a cross-sectional perspective view of an essential part showing an example of an inspection region (measurement pattern) in the thin film solar cell module according to Embodiment 1 of the present invention. FIG. 5 is an example of a cross-sectional view taken along line B-B ′ in FIG. 4, and is a cross-sectional view showing an example of the structure of a measurement pattern element that can be used for evaluating the PN junction of the semiconductor layer of the photoelectric conversion layer. FIG. 6 is an example of a cross-sectional view taken along the line BB ′ in FIG. 4, and is a cross section showing an example of the structure of a measurement pattern element that can be used for evaluating the contact resistance between the back surface metal electrode layer and the front surface transparent conductive film. FIG. FIG. 7 is another example of a cross-sectional view taken along line BB ′ in FIG. 4, and shows another example of the structure of the measurement pattern element that can be used for evaluating the contact resistance between the back surface metal electrode layer and the surface transparent conductive film. It is sectional drawing which shows an example. FIG. 8 is a perspective cross-sectional view of a main part showing a position measurement pattern formed in the outer laminated region (non-photoelectric conversion region 1) in the thin film solar cell module according to the first embodiment and used for alignment in the laser scribing apparatus. FIG. 9 is an example of a cross-sectional view taken along line C-C ′ of FIG. 8. FIG. 10 is a plan view showing another measurement pattern according to the second embodiment used for alignment in the laser scribing apparatus. FIG. 11 is an example of a cross-sectional view taken along line D-D ′ of FIG. 10. FIG. 12: is principal part sectional drawing which shows schematic structure of the thin film solar cell module concerning Embodiment 3 of this invention. FIG. 13: is a flowchart which shows the manufacturing process and inspection process of a thin film solar cell module concerning Embodiment 3 of this invention. FIG. 14 is a characteristic diagram showing the base dependency of crystallinity when a microcrystalline silicon film is formed over microcrystalline silicon films having different crystallinity. FIG. 15: is principal part sectional drawing which shows schematic structure of the thin film solar cell module by a prior art. FIG. 16 is a schematic diagram showing how probe light is scattered during optical inspection of a solar cell according to the prior art. FIG. 17 is a schematic diagram illustrating a state of scattering of probe light at the time of optical inspection when the solar cell module according to Embodiment 3 of the present invention is manufactured. FIG. 18 is a schematic diagram for explaining the definition of the root mean square roughness (RMS). FIG. 19: is principal part sectional drawing which shows schematic structure of the thin film solar cell module concerning Embodiment 4 of this invention. FIG. 20 is a flowchart illustrating a manufacturing process and an inspection process of the thin-film solar cell module according to the fourth embodiment. FIG. 21 is a schematic diagram showing the structure of the transparent conductive film material when the transparent conductive film is processed and flattened by a laser. FIG. 22 is a schematic diagram showing a current conduction path when a transparent conductive film is processed and flattened by a laser. FIG. 23: is sectional drawing which shows typically schematic structure of the thin film solar cell module concerning Embodiment 5 of this invention.

  Embodiments of a thin film solar cell module and a method for manufacturing the same according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited to the following description, In the range which does not deviate from the summary of this invention, it can change suitably. In the drawings shown below, the scale of each member may be different from the actual scale for easy understanding. The same applies between the drawings. Further, even a plan view may be hatched to make the drawing easy to see.

Embodiment 1 FIG.
FIG. 1 is a plan view showing a schematic configuration of a thin-film solar cell module 10 according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view showing a schematic configuration of the thin-film solar cell module 10 according to Embodiment 1 of the present invention, and is a cross-sectional view taken along the line AA ′ of FIG.

  The thin-film solar cell module 10 has a plurality of (herein, seven) thin-film solar cells (hereinafter simply referred to as cells) C arranged in a predetermined direction (in the figure) on a translucent insulating substrate 11 such as a glass substrate or a resin substrate. , In the left-right direction). That is, the cells C1 to C7 are electrically connected in series. Each cell C is formed by sequentially laminating a surface transparent conductive film 12, a photoelectric conversion layer 13, a back transparent conductive film 14, and a back metal electrode layer 15. The surface transparent conductive film 12 of a certain cell C is connected to the back metal electrode layer 15 of one adjacent cell C (the left adjacent in FIG. 2), and the back metal electrode layer 15 is connected to the other adjacent (right in FIG. 2) It is connected to the surface transparent conductive film 12 of the adjacent cell C. With such connection, all the cells C in the thin film solar cell module 10 are electrically connected in series.

  Further, the side of the cell C1 on one end side (left end in FIGS. 1 and 2) of the thin film solar cell module 10 is a non-photoelectric conversion region 1. In the non-photoelectric conversion region 1, the same stacked structure as the cell C is formed on the translucent insulating substrate 11, and the measurement pattern element 2 that is an inspection region is arranged in a part thereof. On the back surface metal electrode layer 15 having a laminated structure of the non-photoelectric conversion region 1 including the measurement pattern element 2, a front electrode layer-side bus bar electrode 21 serving as an extraction electrode is formed. Therefore, the measurement pattern element 2 is formed in the lower region of the front electrode layer side bus bar electrode 21.

  Further, on the back surface metal electrode layer 15 of the cell C7 on the other end side (the right end in FIGS. 1 and 2) side of the thin film solar cell module 10, a back electrode layer side bus bar electrode 22 as an extraction electrode is formed. . In FIG. 1, illustration of the front electrode layer side bus bar electrode 21 and the back electrode layer side bus bar electrode 22 is omitted.

  In the thin film solar cell module 10, the region (cell C7) under the back electrode layer side bus bar electrode 22 contributes to power generation. However, the surface electrode layer-side bus bar electrode 21 is electrically directly connected to the surface transparent conductive film 12 of the adjacent cell C <b> 1 via the metal electrode layer 3. Therefore, it can be seen that the area under the front electrode layer side bus bar electrode 21 does not affect the output of the thin-film solar cell module 10 in any shape. For this reason, in the thin film solar cell module 10, the area | region under the surface electrode layer side bus-bar electrode 21 is the non-photoelectric conversion area | region 1. FIG.

  Therefore, the measurement pattern is used as an inspection region for electrical evaluation that is electrically independent of the cell C in the region below the surface electrode layer-side busbar electrode 21 by utilizing the feature of the structure of the surface electrode layer-side busbar electrode 21. By disposing the element 2, it is possible to evaluate in detail the conductivity of the electrode layer, the evaluation of the PN junction, the finished state of the laser scribing process, the contact resistance between the surface transparent conductive film 12 and the back surface metal electrode layer 15, and the like. .

  FIG. 3 is a flowchart showing manufacturing steps of the thin film solar cell module. Hereinafter, a manufacturing process of a general thin film solar cell module will be described with reference to FIG. First, the translucent insulating substrate 11 such as a glass substrate is cleaned (step S10). Next, a transparent conductive film that becomes the surface transparent conductive film 12 is formed on the translucent insulating substrate 11 (step S20). The transparent conductive film is made of, for example, a low-resistance material such as tin oxide, zinc oxide, or indium oxide that has translucency with respect to light having a wavelength of 300 to 400 nm or more and has a sheet resistance of 10 to 20Ω / □ or less. Used. For forming a transparent conductive film, for example, sputtering, plasma CVD (chemical vapor deposition), MO-CVD (Metal Organic Chemical Vapor Deposition), vapor deposition, coating Laws are used.

  Next, the transparent conductive film is etched by immersing the translucent insulating substrate 11 on which the transparent conductive film is formed in an aqueous solution containing an etching agent, thereby forming an uneven shape as a texture structure on the surface of the transparent conductive film. (Step S30). For the transparent conductive film made of zinc oxide, phosphoric acid, acetic acid or the like is used as an etching agent. For a transparent conductive film made of indium oxide or tin oxide, sulfuric acid, hydrochloric acid, aqua regia, phosphoric acid, hydrobromic acid or the like is used as an etching agent.

  Next, a part of the transparent conductive film is cut and removed in a stripe shape in a direction substantially parallel to the longitudinal direction of the translucent insulating substrate 11, and the transparent conductive film is patterned into a strip shape, and a plurality of surface transparent conductive films 12 is separated. The transparent conductive film is patterned by forming a first stripe-shaped groove extending in a direction substantially parallel to the longitudinal direction of the translucent insulating substrate 11 and reaching the translucent insulating substrate 11 by a laser scribing method. (Step S40).

  Next, a semiconductor layer to be the photoelectric conversion layer 13 is formed on the surface transparent conductive film 12 including the first groove (step S50). In each cell C, the photoelectric conversion layer 13 in which three semiconductor layers of a p-type semiconductor layer, an i-type semiconductor layer, and an n-type semiconductor layer are stacked from the light-transmitting insulating substrate 11 side operates as one solar cell element. In the single-layer thin film solar cell, one set of the photoelectric conversion layers 13 of the combination of the semiconductor layers is stacked, and in the stacked thin film solar cell, a plurality of sets are stacked. The three semiconductor layers are preferably formed continuously in a clean vacuum so that unintended impurities (dust and unexpected elements) do not enter the semiconductor layers as much as possible.

  In single-layer thin-film solar cells, amorphous silicon, amorphous silicon carbide, amorphous silicon oxide, microcrystalline silicon, microcrystalline silicon carbide, microcrystalline silicon oxide, etc. are formed as a p-type semiconductor layer by plasma CVD, hot wire CVD, etc. Is done. In the i-type semiconductor layer, amorphous silicon, amorphous silicon carbide, amorphous silicon oxide, amorphous silicon germanium, or the like is formed by a plasma CVD method, a hot wire CVD method, or the like. In the n-type semiconductor layer, amorphous silicon, microcrystalline silicon, or the like is formed by a plasma CVD method, a hot wire CVD method, or the like.

  The stacked thin film solar cell is a solar cell in which the i-type semiconductor layer is made of amorphous silicon germanium, microcrystalline silicon, microcrystalline silicon germanium, microcrystalline germanium, or the like on the semiconductor layer used in the single-layer thin film solar cell. It has a structure in which one or more elements are stacked. In the case of a laminated thin film solar cell, a semitransparent layer for optical design called an intermediate layer may be inserted between the solar cell elements. This intermediate layer is made of, for example, microcrystalline silicon oxide, zinc oxide, tin oxide or the like, and has a characteristic of reflecting some incident light forward and transmitting the remaining light backward.

  Next, the back transparent conductive film 14 is formed on the photoelectric conversion layer 13 by the same material and method as those for forming the front electrode layer (step S60). At this time, the back transparent conductive film 14 has a role of preventing the metal used for the back metal electrode layer 15 from diffusing into the semiconductor layer of the photoelectric conversion layer 13.

  Next, the photoelectric conversion layer 13 and the back surface transparent conductive film 14 are patterned by laser scribing similarly to the front surface transparent conductive film 12 (step S70). That is, a part of the photoelectric conversion layer 13 and the back surface transparent conductive film 14 is cut and removed in a stripe shape in a direction substantially parallel to the longitudinal direction of the translucent insulating substrate 11, so that the photoelectric conversion layer 13 and the back surface transparent conductive film 14 are removed. Are patterned into strips and separated. This patterning is performed in a striped second groove (connection groove) that extends in a direction substantially parallel to the longitudinal direction of the translucent insulating substrate 11 and reaches the surface transparent conductive film 12 at a location different from the first groove. This is done by forming

  Next, the back surface metal electrode layer 15 is formed in the second groove (connection groove) and on the back surface transparent conductive film 14 (step S80). Back metal electrode layer 15 is formed of a metal such as silver, aluminum, or titanium by, for example, sputtering. At this time, the back surface metal electrode layer 15 is formed under the condition that the back surface metal electrode layer 15 is formed along the inner wall of the second groove (connection groove). Thereby, the inner surface of the second groove (connection groove) is covered with the back surface metal electrode layer 15, and electrical connection between the back surface metal electrode layer 15 on the back surface transparent conductive film 14 and the surface transparent conductive film 12 is ensured. Is done.

  Next, a part of the back surface metal electrode layer 15, the back surface transparent conductive film 14, and the photoelectric conversion layer 13 is cut and removed in a stripe shape in a direction substantially parallel to the longitudinal direction of the translucent insulating substrate 11 and patterned into a strip shape. Then, it is separated into a plurality of cells C. The surface transparent conductive film is patterned by a laser scribing method, extending in a direction substantially parallel to the longitudinal direction of the translucent insulating substrate 11 at a location different from the first groove and the second groove (connection groove). This is performed by forming a striped third groove (separation groove) reaching 12 (step S90). Thus, the cells C electrically connected in series are formed.

  Finally, a modularization process is performed. That is, the bus bar electrode made of aluminum or copper is connected to the current drawing portion of the cell C at both ends by solder, ultrasonic processing, conductive adhesive or the like, and is modularized by a sealing material, a back sheet, and a frame (step S100). ). As described above, a separation step by laser scribe or mechanical scribe for connecting the solar cell elements in the translucent insulating substrate 11 in series is performed between the above steps.

  After execution of the manufacturing flow as described above, a thin film solar cell module in which the cells C arranged in a vertically long strip shape are electrically connected in series is formed. Here, when electrical evaluation of the cell C is performed using each formed cell C, the influence of the adjacent cells C connected in series, the vertically transparent front surface conductive film 12 and the back surface metal electrode The influence of the resistance value of the layer 15 becomes large, and the semiconductor layer of the photoelectric conversion layer 13 cannot be sufficiently analyzed. Further, the contact resistance of the connection portion between the front transparent conductive film 12 and the back metal electrode layer 15 cannot be evaluated.

  Therefore, in the present embodiment, in the manufacturing flow of FIG. 3, the transparent conductive film is etched (step S30), the back transparent conductive film is formed (step S70), and the back electrode is formed (step S90). At the time of processing each layer in the laser scribing process (step S40, step S70, step S90), an evaluation element for measuring electrical characteristics is formed in the non-photoelectric conversion region 1. That is, as shown in FIG. 4, in the non-photoelectric conversion region 1 next to the cell C1 on the one end side of the thin-film solar cell module 10, which is outside the formation region of the cell C on the translucent insulating substrate 11. An external laminated region in which the same laminated structure as that of the cell C is formed is provided, and the laminated film in the external laminated region is cut into small regions, and the measurement pattern element 2 is formed as an inspection region which is an electrically independent evaluation pattern. Thus, an evaluation element is installed. FIG. 4 is a main-part cross-sectional perspective view showing an example of the measurement pattern element 2 in the thin-film solar cell module 10 according to the first embodiment. The measurement pattern element 2 is separated from other regions in the outer stacked region (non-photoelectric conversion region 1) by a separation groove 31 reaching the translucent insulating substrate 11 from the upper surface of the back surface metal electrode layer 15. Therefore, the evaluation element is electrically separated from the other regions in the outer laminated region (non-photoelectric conversion region 1).

  Various structures of the measurement pattern element 2 can be considered, and FIG. 4 shows an example thereof. FIG. 5 is an example of a cross-sectional view taken along line BB ′ in FIG. 4, and is a cross-section illustrating an example of the structure of the measurement pattern element 2 that can be used for evaluating the PN junction of the semiconductor layer of the photoelectric conversion layer 13. FIG. FIG. 6 is an example of a cross-sectional view taken along the line BB ′ in FIG. 4, and the structure of the measurement pattern element 2 that can be used for evaluating the contact resistance between the back surface metal electrode layer 15 and the surface transparent conductive film 12. It is sectional drawing which shows an example.

  Each layer constituting the measurement pattern element 2 for evaluation is laminated in the same process as the cell C. And the process of the groove | channel for forming the measurement pattern element 2 containing the isolation | separation groove | channel 31 is performed simultaneously in the formation process of the cell C mentioned above. For this reason, an additional process such as mask formation or etching for forming the measurement pattern element 2 is not necessary.

  Further, the measurement pattern element 2 reaches the translucent insulating substrate 11 from the upper surface of the back surface metal electrode layer 15, and the layers from the photoelectric conversion layer 13 to the back surface metal electrode layer 15 in the measurement pattern element 2 are divided into a plurality of small regions, That is, a separation groove 32 that is divided into the measurement unit 2a and the measurement unit 2b is formed. The processing of the separation groove 32 is simultaneously performed in the above-described process of forming the cell C. For this reason, an additional process such as mask formation or etching for forming the measurement pattern element 2 is not necessary.

  In the case of the measurement pattern element 2 shown in FIG. 5, the electrical characteristics can be evaluated by measuring the current flowing in the semiconductor layer in the vertical direction (stacking direction) using the electrode layer closest to the PN junction of the semiconductor layer. Therefore, the change in junction capacitance due to diode characteristics and CV (capacitance voltage) measurement is measured, the doping concentration of the p-type semiconductor layer and the n-type semiconductor layer, and the depletion layer region in the i-type semiconductor layer It is possible to evaluate the width. The CV measurement of the PN layer is expressed by a step junction model (Formula 1). For this reason, by analyzing the measurement result using Equation 1, the doping concentration of each semiconductor layer and the numerical value of the diffusion potential can be evaluated.

  Further, the current-voltage characteristic of the cell C when no light is irradiated can be expressed by an equivalent circuit using a diode equation (Equation 2), a series resistor, and a shunt resistor.

  In this case, it can be said that the smaller the saturation current, the smaller the recombination at the junction interface of the elements, and the better the diode. In addition, since the value of the diode factor reflects the recombination current in the diode, it can be used for managing the manufacturing conditions of the semiconductor layer.

  These are important parameters that determine the voltage and fill factor of the solar cell. However, since the area of a single cell is too large for a module, the influence of the resistance of the electrode layer is large. There wasn't.

  On the other hand, in the thin film solar cell module 10 according to the present embodiment, the non-photoelectric conversion region 1 is provided with an external stacked region in which the same stacked structure as the cell C is formed, and a small area measurement is performed in the external stacked region. Since the pattern element 2 is provided, it is possible to correctly measure and evaluate the electric characteristics of the cell C while suppressing the influence of the resistance of the electrode layer. The size of one measurement electrode, that is, the size of one measurement pattern element 2 may be approximately 3 mm square or more, and preferably about 5 mm square that fits in the installation region of the surface electrode layer side bus bar electrode 21.

  In the measurement pattern element 2 shown in FIG. 6, the adjacent back surface metal electrode layers 15 are in contact with and electrically connected to the surface transparent conductive film 12 at two locations. The resistance Rele between the adjacent back surface metal electrode layers at this time is expressed by Equation 3.

  Furthermore, as shown in FIG. 7, by simultaneously arranging a pattern in which the distance between two points where the back surface metal electrode layer 15 and the surface transparent conductive film 12 are in contact with those in FIG. The resistance Rtco of the conductive film 12 can be calculated. FIG. 7 is another example of a cross-sectional view taken along the line BB ′ in FIG. 4, and the structure of the measurement pattern element 2 that can be used for evaluating the contact resistance between the back surface metal electrode layer 15 and the surface transparent conductive film 12. It is sectional drawing which shows another example.

  In general, the resistance value of a metal electrode is very small compared to the contact resistance between the metal electrode and the transparent conductive film or the transparent conductive film. Therefore, if the resistance Rele between the adjacent backside metal electrode layers can be ignored, Equation 3 is approximated to Equation 4, and the contact resistance Rcont is calculated by substituting the previously calculated resistance Rtco of the surface transparent conductive film 12. can do.

  This contact resistance Rcont is caused by damage to the surface transparent conductive film 12 due to the laser scribing process, variation in processing size, and coverage (covering state) with respect to the processing hole (second groove (connection groove)) of the back surface metal electrode layer 15. Since it changes, evaluation of a laser scribing process and a back surface metal electrode layer 15 formation process is attained. In the structure of the measurement pattern element 2 for measuring the contact resistance Rcont, the error is reduced when the distance between the contact positions of the back surface metal electrode layer 15 and the front surface transparent conductive film 12 is largely changed. It may be used.

  When the contact resistance Rcont is larger than a predetermined specified value, the surface transparent conductive film 12 is damaged because the laser power when the semiconductor layer of the photoelectric conversion layer 13 is scribed is too strong. In this case, the contact resistance Rcont can be returned to the specified value by lowering the focus position and power density of the laser scribe. When the current-voltage characteristics cannot be approximated by a linear line, a semiconductor layer remains between the front transparent conductive film 12 and the back metal electrode layer 15 to form an electrical barrier. In this case, the semiconductor layer remaining between the front transparent conductive film 12 and the back metal electrode layer 15 can be eliminated by selecting the manufacturing process conditions so as to increase the power density of the laser scribe.

  In order to perform these evaluations more easily and accurately, it is preferable to form the measurement pattern element 2 on a flat substrate. When a voltage is applied to the measurement pattern element 2 formed on the surface transparent conductive film 12 having a large concavo-convex shape, the electric field concentrates at the apex of the convex portion, so that the measurement pattern element 2 is destroyed and expressed in Equation 1. No complex CV characteristics may be measured. In order to prevent this, the measurement pattern element 2 is preferably formed on a flat substrate close to an ideal state.

  For example, in the manufacturing flow of FIG. 2, after forming a transparent conductive film on the translucent insulating substrate 11, the surface electrode layer side bus bar in the outer laminated region (non-photoelectric conversion region 1) on the translucent insulating substrate 11. Masking the arrangement position of the electrode 21 with a protective film, tape, or the like, and then etching to form an uneven shape. Thereby, an uneven | corrugated shape can be formed in the surface transparent conductive film 12 of an electric power generation part (cell C), leaving a flat part in a part (surface transparent conductive film 12 in the measurement pattern element 2) of a transparent conductive film. .

  As a method for forming a concavo-convex shape in a transparent conductive film, a dry process and a wet process can be roughly classified. First, the case where it processes by a dry process is demonstrated. The dry process is a process in which a surface is processed by chemical reaction with a gas or physical contact with molecules. In this case, a flat surface can be obtained by preventing gas and molecules from coming into contact with the surface of the transparent conductive film.

  When physical processing is performed by applying fine substances or molecules to the surface, such as blasting or plasma etching with argon ions, a mask such as a plate that blocks these flying is placed on the front surface of the transparent conductive film. Thereby, a flat surface is obtained on the surface of the transparent conductive film.

  In the case of a chemical reaction between a gas such as fluorine-containing compound gas such as tetrafluorocarbon, hydrogen, or hydrocarbon and a transparent conductive film, the surface of the gas is activated by the chemical reaction when the active gas molecules reach the surface of the transparent conductive film. (For example, see Reference: “Japanese Patent Application No. 2008-161341”). Therefore, depending on the processing conditions that increase the lifetime of the reactive species, such as low pressure, the reactive gas can enter the surface of the transparent conductive film unintentionally by simply placing a mask on the surface of the transparent conductive film. There is a possibility that. In such a case, it is necessary to prepare a mask that adheres to the surface to be protected, such as an adhesive film or a tape.

  Next, the case of processing by a wet process will be described. The wet process is a method of processing by immersing a substrate on which a transparent conductive film is formed in an aqueous solution containing an etching agent. For the transparent conductive film made of zinc oxide, phosphoric acid, acetic acid or the like is used as an etching agent. For a transparent conductive film made of indium oxide or tin oxide, sulfuric acid, hydrochloric acid, aqua regia, phosphoric acid, hydrobromic acid or the like is used as an etching agent.

  Since the substrate is immersed in the aqueous solution, unintended etching due to the wraparound of the aqueous solution is likely to occur as in the case of using the chemical reaction of the gas. Therefore, also in the case of a wet process, it is necessary to use as a mask a protective sheet or the like that can be in close contact with the flat portion and is resistant to chemicals such as acids.

  As described above, in the first embodiment, as the electrical evaluation element, the surface electrode layer-side busbar electrode 21 in the non-photoelectric conversion region 1 of the thin film solar cell module 10 that is an external region of the cell C formation region. A measurement pattern element 2 for electrical evaluation that is electrically independent of the cell C is formed in the lower region. By measuring various electrical characteristics using this electrical evaluation element, the electrical conductivity and PN junction of the electrode layer, the finished state of the laser scribe process, the surface transparent conductive film 12 and the back metal electrode layer 15 Electrical characteristics such as contact resistance can be evaluated in detail.

  In addition, when measuring and evaluating the electrical characteristics of a large area, there is a high possibility that a partial defect is included. In this case, the electrical characteristics of the original laminated film cannot be accurately performed due to the influence of the defect. There is a case. Further, when measuring / evaluating electrical characteristics for a large area, the resistance of the electrode layer becomes a non-negligible magnitude, which may adversely affect measurement / analysis. However, in the first embodiment, since it is possible to evaluate by measuring and evaluating the electrical characteristics in a small-area inspection region, it is possible to suppress adverse effects on measurement and analysis due to partial defects.

  Moreover, in Embodiment 1, since the test | inspection area | region is provided under the surface electrode layer side bus-bar electrode 21 which does not contribute to electric power generation, the power generation performance fall in a thin film solar cell module does not generate | occur | produce. Further, if the inspection area is large, the connection area between the cell C and the bus bar electrode may be reduced, but the evaluation area in the first embodiment is a small area that can be accommodated in the front electrode layer side bus bar electrode 21. The influence on the connection between the cell C and the bus bar electrode is very small.

  Moreover, in Embodiment 1, since the groove | channel of the measurement pattern element 2 exists under the surface electrode layer side bus-bar electrode 21, the laminated film of the surface electrode layer side bus-bar electrode 21 and an external lamination area | region (non-photoelectric conversion area | region 1). There is also an effect of relieving the stress caused by the difference in thermal expansion occurring between the two.

  Therefore, according to the first embodiment, it is possible to perform electrical evaluation for each layer and process, which has conventionally been difficult to evaluate, without impairing the power generation efficiency of the thin-film solar cell module. The dependence of electrical characteristics on processing conditions can be easily known, and the manufacturing process can be easily managed. Thereby, the thin film solar cell module excellent in photoelectric conversion efficiency can be obtained with good reproducibility.

Embodiment 2. FIG.
FIG. 8 is a perspective cross-sectional view of a main part showing a position measurement pattern formed in the outer laminated region (non-photoelectric conversion region 1) in the thin film solar cell module according to the first embodiment and used for alignment in the laser scribing apparatus. FIG. 9 is an example of a cross-sectional view taken along the line CC ′ of FIG. In the manufacturing process of the thin film solar cell module described above, there are roughly four laser scribing processes. In the laser scribe process performed after the formation of the transparent conductive film that becomes the surface transparent electrode layer, the laser scribe process performed after the formation of the back transparent conductive film, and the laser scribe process performed twice after the formation of the back metal electrode, the objects to be scribed Is different. That is, the transparent conductive film is processed in the second laser scribing step after the formation of the transparent conductive film and the back surface metal electrode. In the first laser scribing step after forming the back transparent conductive film and after forming the back metal electrode, the silicon film is processed.

  Therefore, at least two different laser light sources need to be used in the laser scribe process. For this reason, it is necessary to perform alignment for each laser scribing process so that the positional deviation between the planned processing position and the actual processing position is eliminated.

  Therefore, the position measurement patterns shown in FIGS. 8 and 9 are patterns used when adjusting the processing position in each laser scribing process, and are the external laminated region (non-photoelectric conversion region 1) on the translucent insulating substrate 11. Are provided in a quadrangular shape at specific positions. In this pattern, the initial transparent conductive film scribe mark 51 (corresponding to the laser scribe process after forming the transparent conductive film), the semiconductor layer scribe mark 52 (corresponding to the laser scribe process after forming the back transparent conductive film), the back surface metal electrode Each scribe trace pattern of layer scribe trace 53 (corresponding to the first laser scribe process after the formation of the back metal electrode) and late transparent conductive film scribe trace 54 (corresponding to the second laser scribe process after the formation of the back metal electrode) Is formed. By measuring and calculating the distance and parallelism of each line of the scribe trace pattern by inspection with an optical microscope, a laser microscope, a stylus type step gauge, etc., the one side direction and the other side direction of the translucent insulating substrate 11 orthogonal to each other Laser scribe misalignment in the x-axis direction and y-axis direction in FIG. 8 can be detected.

  That is, the initial transparent conductive film scribe mark 51 is formed during the laser scribing process after the formation of the transparent conductive film. Thereafter, before the laser scribing of the semiconductor layer is performed after the formation of the semiconductor layer (photoelectric conversion layer 13) and the back surface transparent conductive film 14, the semiconductor layer scribe trace 52 is formed, and the distance and angle with the initial transparent conductive film scribe trace 51 are formed. The scribe device is adjusted based on the result. Hereinafter, in the same manner, before performing laser scribing in the subsequent scribing process in the manufacturing process of the thin film solar cell module, by forming and inspecting the back surface metal electrode layer scribe trace 53 and the late transparent conductive film scribe trace 54, The scribing device is adjusted based on the result. Thereby, alignment of the scribe position at the time of a laser scribe process can be performed.

  FIG. 10 is a plan view showing another position measurement pattern according to the second embodiment used for alignment in the laser scribing apparatus. FIG. 11 is an example of a cross-sectional view taken along line C-C ′ of FIG. 10. When the positional deviation of the laser scribe is evaluated more simply, the square pattern as described above may not be used. For example, as shown in FIG. 10 and FIG. 11, before each laser scribing step, a line having a certain angle and length is drawn by laser scribing, and the positional deviation can be evaluated from these positional relationships.

  Therefore, according to the second embodiment, the scribe position can be aligned at the time of the laser scribe process without impairing the power generation efficiency of the thin-film solar cell module and without increasing the number of processes. It is possible to easily know the variation in the manufacturing process, and it is possible to easily manage the manufacturing process. Thereby, the thin film solar cell module excellent in photoelectric conversion efficiency can be obtained with good reproducibility.

Embodiment 3 FIG.
FIG. 12: is principal part sectional drawing which shows schematic structure of the thin film solar cell module concerning Embodiment 3 of this invention. FIG. 12 shows the vicinity of the non-photoelectric conversion region 1. As described in the first and second embodiments, the region where the bus bar electrode in the vicinity of the end portion of the thin-film solar cell module is disposed is the non-photoelectric conversion region 1 and is not related to the output of the solar cell. Therefore, it is not necessary to scatter light in the non-photoelectric conversion region 1, and even if the surface on the side where the surface transparent conductive film of the translucent insulating substrate 11 is formed is a flat portion, the output of the solar cell Has no effect. This flat portion can be used not only for electrical inspection but also for optical inspection steps of the respective film forming processes, and accurate inspection can be performed with a simple optical model.

  In the thin-film solar cell module according to the third embodiment, the texture structure is formed on the surface of the translucent insulating substrate 11 in the formation part of the cell C, and the surface of the translucent insulating substrate 11 in the non-photoelectric conversion region 1. The basic structure is the same as that of the thin film solar cell module 10 according to the first embodiment except that is a flat portion. Therefore, in FIG. 12, detailed description is abbreviate | omitted by attaching | subjecting the same code | symbol as the thin film solar cell module 10. FIG. Although illustration and description are omitted, the measurement pattern element 2 and the position measurement pattern which are the grooves described in the first and second embodiments are formed.

  In order to form a texture structure on the glass substrate as the translucent insulating substrate 11, a physical texture forming method such as blasting or a texture by chemical action using fluorine gas, carbon tetrafluoride gas or the like. The forming method is effective. When such processing is performed, a flat region can be easily produced by performing texture processing after masking a desired region with a mask such as an adhesive sheet. Thereafter, the mask is removed, and the glass substrate is cleaned and inspected. Since a flat portion is also formed at the same time as texture processing, it is possible to form a flat non-photoelectric conversion region 1 on the surface of the light-transmitting insulating substrate 11 without increasing the number of steps.

  Below, the manufacturing process and inspection process of the thin film solar cell module concerning Embodiment 3 are demonstrated. FIG. 13 is a flowchart showing a manufacturing process and an inspection process of the thin-film solar cell module according to the third embodiment.

  First, after the glass substrate (textured glass substrate) having a texture structure formed on the surface is washed as the light-transmitting insulating substrate 11 (step S110), the transparent conductive film that becomes the surface transparent conductive film 12 is formed according to the first embodiment. As in the case, a film is formed on the translucent insulating substrate 11 (step S120). The film thickness and composition of the transparent conductive film have a great influence on the light transmittance. For this reason, after film formation of the transparent conductive film, the film thickness, composition, etc. of the transparent conductive film are optically inspected by a spectroscope or spectroscopic ellipsometry (step S130), and it is confirmed that there is no problem in the film formation process of the transparent conductive film.

  Here, when there is a problem in the film formation process of the transparent conductive film, the process is reviewed from the next film formation process of the transparent conductive film to change the conditions of the film formation process. For example, when the refractive index of the formed transparent conductive film is high, if the film formation method is a sputtering method or a plasma CVD method, the oxygen concentration in the growth atmosphere is increased, and the oxygen composition is increased. It is possible to lower the refractive index.

  Next, similarly to the case of the first embodiment, the transparent conductive film is patterned into a strip shape by the laser scribing method and separated into a plurality of surface transparent conductive films 12 (step S140).

  Since the texture structure which is a light confinement structure has already been formed on the surface of the glass substrate, after the formation of the surface transparent conductive film 12, the semiconductor layer of the photoelectric conversion layer 13 is formed in the same manner as in the first embodiment. (Step S150).

  Next, an optical inspection of the semiconductor layer of the photoelectric conversion layer 13 is performed (step S160), and it is confirmed that there is no problem in the film formation process of the semiconductor layer. In the case of a p-type semiconductor layer, an i-type semiconductor layer, an n-type semiconductor layer, and a stacked type, in order to inspect the film thickness of each intermediate layer, it is difficult only by measuring light transmittance and light reflectance, It is necessary to obtain the film thickness, refractive index, and crystallization ratio of each layer by measurement and analysis using spectroscopic ellipsometry. Furthermore, to control the light inside the semiconductor layer, it is necessary to know the refractive index of the intermediate layer and the films before and after the intermediate layer. When the finished state of each layer is inspected by these optical inspections, and the inspection result is greatly deviated from a predetermined value, it is important to be able to inspect the film forming apparatus and change the conditions of the next process. The optical inspection of the semiconductor layer will be described later.

  Next, the back transparent conductive film 14 is formed on the photoelectric conversion layer 13 in the same manner as in the first embodiment by using the same material and method as those for forming the surface electrode layer (step S170).

  Next, an optical inspection of the back transparent conductive film 14 is performed (step S180), and it is confirmed that there is no problem in the film forming process of the back transparent conductive film 14.

  Next, the photoelectric conversion layer 13 and the back surface transparent conductive film 14 are patterned by laser scribing in the same manner as in the first embodiment (step S190). That is, a part of the photoelectric conversion layer 13 and the back surface transparent conductive film 14 is cut and removed in a stripe shape in a direction substantially parallel to the longitudinal direction of the translucent insulating substrate 11, so that the photoelectric conversion layer 13 and the back surface transparent conductive film 14 are removed. Are patterned into strips and separated.

  Next, the back metal electrode layer 15 is formed in the same manner as in the first embodiment (step S200).

  Next, as in the case of the first embodiment, the back metal electrode layer 15, the back transparent conductive film 14, and the photoelectric conversion layer 13 are partially parallel to the longitudinal direction of the translucent insulating substrate 11 by laser scribing. The strips are cut and removed in the direction of stripes and patterned into strips to be separated into a plurality of cells C (step S210). Thus, the cells C electrically connected in series are formed.

  Although not described here, in each laser scribing step, the measurement pattern element 2 and the position measurement pattern which are the grooves described in the first and second embodiments are formed and the scribe position is aligned.

  Next, the final confirmation of the scribe position by optical inspection and the electrical inspection described in the first embodiment are performed using the measurement pattern element 2 and the position measurement pattern (step S220). Finally, a modularization process is performed. That is, the bus bar electrode made of aluminum or copper is connected to the current extraction part of the cell C at both ends by solder, ultrasonic processing, conductive adhesive or the like, and modularized by the sealing material, the back sheet, and the frame (step S230). ).

  Next, optical inspection of the semiconductor layer will be described. In a single-junction thin film solar cell, a film formation process for three layers of a p-type semiconductor layer, an intrinsic semiconductor layer, and an n-type semiconductor layer is performed. In the case of a stacked thin-film solar cell, solar cell elements composed of the above three layers are formed as many as the number of stacked layers. In the junction type, six layers are formed, and in the case of using an intermediate junction layer, seven layers are formed. In addition, it goes through the process for the intermediate bonding layer. The film thickness and refractive index inspection process after the formation of these semiconductor layers and the subsequent formation of the back surface transparent conductive film 14 is a very important process for stably producing a high-quality product.

  For example, when the film thickness of the p-type semiconductor layer is too thin, the electric field in the semiconductor layer is lowered and the output voltage is lowered. On the other hand, when the film thickness of the p-type semiconductor layer is too thick, the light absorbed by the p-type semiconductor layer is not converted into a current, leading to a decrease in current. Generally, the film thickness of the p-type semiconductor layer is controlled between 10 nm and 20 nm, and the power generation performance is affected only by the film thickness being deviated by about 30% from the set value.

  In the inventors' investigation, in a single-junction thin film solar cell using amorphous silicon carbide for the p-type semiconductor layer, amorphous silicon for the i-type semiconductor layer, and microcrystalline silicon for the n-type semiconductor layer, the film of the p-type semiconductor layer When the thickness decreases from 10 nm to 7 nm, the output voltage decreases from 850 mV to 820 mV. For example, in a thin film solar cell module in which about 140 identical cells C are connected in series, when the output voltage drops due to the film thickness of the p-type semiconductor layer, an output voltage of 119V is originally obtained. The output voltage obtained is 116V, which is about 3% voltage drop. Furthermore, due to the effect of the electric field in the semiconductor layer being lowered, the fill factor is lowered and the maximum output is reduced by 3% or more.

  In microcrystalline silicon used for an n-type semiconductor layer and microcrystalline silicon oxide or zinc oxide used as an intermediate layer, not only the film thickness but also crystallinity, refractive index, etc. affect solar cell performance. Note that in this specification, a film made of a mixture of crystalline silicon and amorphous silicon is defined as a microcrystalline silicon film. The n-type semiconductor layer not only affects the output voltage, but also has a function of forming a junction with the second-layer (next-layer) solar cell element in a multi-junction solar cell. For this reason, the series resistance increases and the fill factor decreases due to an increase in film thickness and a decrease in crystallinity in microcrystalline silicon used for the n-type semiconductor layer.

  In the case where a microcrystalline silicon oxide layer which is an intermediate layer is formed over the n-type semiconductor layer, the crystallinity of the microcrystalline silicon oxide layer also varies depending on the crystallinity of the n-type semiconductor layer. Even if the microcrystalline silicon oxide layer is formed under the same conditions, the crystallinity of the initial growth layer varies greatly depending on the crystallinity of the base. For this reason, it is necessary to control the crystallinity of the n-type semiconductor layer so that it is as designed.

  FIG. 14 shows the base dependency of the crystallinity when the second microcrystalline silicon film is formed under the same conditions on the microcrystalline silicon films having different crystallinity (the second microcrystalline silicon film has FIG. 6 is a characteristic diagram showing a crystallinity dependency of a ground crystallinity). FIG. 14 shows the crystallinity of the second microcrystalline silicon film at the film thickness of 50 nm. Here, the degree of crystallinity is an index calculated using Equation 5 from the peak intensity derived from crystalline silicon and the peak intensity derived from amorphous silicon in the spectrum obtained by Raman scattering spectroscopy.

  In the structural analysis of thin films by spectroscopic ellipsometry, the optical model of the thin film to be measured is expressed as a mixture of the optical model of the crystalline silicon film and the optical model of the amorphous silicon film, and the degree of crystallinity is determined by the contribution ratio. It can also be defined.

According to the result of FIG. 14, even when the microcrystalline silicon film is grown under the same growth conditions and with the same film thickness, when the base film is an amorphous film, the crystallinity is as low as 0.4. It can be seen that as the crystallinity of the film increases, the crystallinity of the microcrystalline silicon film grown thereon changes from 1 to 4.3. Since the conductivity of the microcrystalline silicon film varies greatly from the 10 ⁻⁶ S / cm level to the 10 S / cm level depending on the degree of crystallinity, the influence on the output of the solar cell module is very large.

  However, it is difficult to inspect the film thickness of these layers in a nondestructive manner. Even if an attempt is made to measure by light reflectance or spectroscopic ellipsometry, the structure of the conventional thin film solar cell module as shown in FIG. As shown, the incident light 61 is scattered by the concavo-convex structure on the surface of the photoelectric conversion layer 13 reflecting the concavo-convex structure on the surface of the translucent insulating substrate 11, so that the reflected light 62 does not reach the measuring device 63. For this reason, in the case of spectroscopic ellipsometry, it is necessary to construct an optical model in consideration of light scattering, and the texture structure also varies, making it difficult to correctly inspect the film thickness and optical characteristics. FIG. 15: is principal part sectional drawing which shows schematic structure of the thin film solar cell module by a prior art. FIG. 16 is a schematic diagram showing how probe light is scattered during optical inspection of a solar cell according to the prior art.

  On the other hand, in the case of an optical inspection on the flat translucent insulating substrate 11, the reflected light 62 is reflected in the same direction as the incident light 61 and returns to the measuring device 63 as shown in FIG. It can be expressed by an optical model in which materials are laminated, and analysis becomes easy. FIG. 17 is a schematic diagram illustrating a state of scattering of probe light during an optical inspection when the solar cell module according to the third embodiment is manufactured.

  For example, reference document “Japanese Patent Laid-Open No. 2010-205892” evaluates an error between the root mean square surface roughness (RMS value) of a semiconductor layer and the actual film thickness calculated by optical measurement. The results are shown in Table 1 below. The RMS value is a value calculated by the following equation 6 using the data of the average line Z0 and the measurement point Zi shown in FIG. FIG. 18 is a schematic diagram for explaining the definition of the root mean square roughness (RMS).

  As can be seen from Table 1, when the RMS value of the concavo-convex shape on the base surface is 25 nm, a measurement error of 10% occurs between the film thickness calculated by optical measurement and the actual film thickness. Further, in order to obtain a high-power thin film solar cell, a concavo-convex shape having an RMS value exceeding 100 nm is also used, and the measurement error is further increased. In the reference document “Japanese Patent Application Laid-Open No. 2010-205892”, a measurement part having a small RMS value is formed by a laser processing apparatus or the like in a limited part of the conductive layer adjacent to the power generation area where the conductive layer is to be removed. The width of the measurement site that can be installed so as not to give a limit is limited to 200 to 300 μm. Furthermore, in order to increase the effective area, it is considered that the region of the conductive layer removal site will become narrower in the future. When it is necessary to evaluate not only the film thickness but also the refractive index and crystallinity, a measurement area with a width of about 2 to 3 mm is generally required for measurement by spectroscopic ellipsometry. It becomes difficult to respond.

  On the other hand, in the thin film solar cell module according to the present embodiment, the surfaces of both end portions of the translucent insulating substrate 11 are flat, and the measurement pattern element 2 is formed at least in the outer laminated region. Is flat. As a result, various inspections and measurements can be performed without reducing the power generation performance. The surface electrode layer side bus bar electrode 21 needs a bus bar electrode width of about 4 to 5 mm so as to collect a current of several amperes and take it out without generating a loss. For this reason, the area | region of the measurement pattern element 2 required for a test | inspection can fully be ensured.

  In the thin film solar cell module according to the present embodiment, finally, the flat portions at both ends of the translucent insulating substrate 11 remain below the surface electrode layer-side bus bar electrode 21. However, since this portion has the same structure as the thin film solar cell C but is an electrically independent region, the thin film solar cell C is not adversely affected.

  Therefore, according to the thin-film solar battery module according to the third embodiment, the thickness, refractive index, and crystallinity of each layer constituting the thin-film solar battery cell C are 10% or less with a simple optical model without additional processing steps. Can be evaluated.

Embodiment 4 FIG.
FIG. 19: is principal part sectional drawing which shows schematic structure of the thin film solar cell module concerning Embodiment 4 of this invention. The difference between the thin-film solar cell module according to the fourth embodiment and the thin-film solar cell module according to the third embodiment is that the surface transparent conductive film 12 has an uneven shape with a texture structure. Thus, even when the surface transparent conductive film 12 is formed on the flat translucent insulating substrate 11 and the surface transparent conductive film 12 is provided with an uneven shape, the power generation is performed in the same manner as in the third embodiment. Optical evaluation can be performed without impairing efficiency.

  Below, the manufacturing process and inspection process of the thin film solar cell module concerning Embodiment 4 are demonstrated. FIG. 20 is a flowchart illustrating a manufacturing process and an inspection process of the thin-film solar cell module according to the fourth embodiment. First, after cleaning the glass substrate as the translucent insulating substrate 11 (step S310), a transparent conductive film to be the surface transparent conductive film 12 is formed on the translucent insulating substrate 11 as in the first embodiment. Film is formed (step S320).

  The film thickness and composition of the transparent conductive film have a great influence on the light transmittance. For this reason, after film formation of a transparent conductive film, the film thickness, composition, etc. of a transparent conductive film are optically inspected by a spectroscope or spectroscopic ellipsometry (step S330), and it is confirmed that there is no problem in the film formation process of a transparent conductive film. Here, when there is a problem in the film formation process of the transparent conductive film, the process is reviewed from the next film formation process of the transparent conductive film to change the conditions of the film formation process.

  Next, in order to keep the surface of the transparent conductive film in the outer laminated region (non-photoelectric conversion region 1) where the inspection region is provided, a mask is attached to this region and masking is performed (step S340). Next, the transparent conductive film is etched by immersing the translucent insulating substrate 11 on which the transparent conductive film is formed in an aqueous solution containing an etching agent, thereby forming an uneven shape as a texture structure on the surface of the transparent conductive film. (Step S350). That is, it is possible to easily produce a flat region on the surface of the transparent conductive film by performing texture processing after masking a desired region with a mask such as an adhesive sheet. Then remove the mask. Subsequent steps S360 to S460 are the same as steps S130 to S230 shown in FIG.

  In addition, in the case of a manufacturing process in which a flat portion is provided in a region where cells are separated by laser scribing as in a reference document “Japanese Patent Laid-Open No. 2010-205892,” a portion where an electrode or a semiconductor layer is removed is a solar cell module. It is also a place where the back electrode and the surface transparent electrode layer are in contact and the cells are connected in series.

  FIG. 21 is a schematic diagram showing the structure of the transparent conductive film material when the transparent conductive film is processed and flattened by a laser. As shown in FIG. 21, once the transparent conductive film material crystal portion 12a is formed as the surface transparent conductive film 12, the surface of the transparent conductive film formed a good crystal when the surface is flattened by laser scribing. The surface of the material crystal part 12a is rapidly cooled after being melted and evaporated at the moment when the laser is irradiated. For this reason, the transparent conductive film material fusion | melting part 12b which is a residue layer with low crystallinity is formed in the outermost surface of the transparent conductive film material crystal | crystallization part 12a, and electroconductivity falls locally. The amorphous transparent conductive film and the crystalline transparent conductive film differ in resistance value by about 1 to 2 digits. For this reason, even if it is a very thin amorphous transparent conductive film (transparent conductive film material melting part 12b), the influence which it has on the resistance value of the whole thin film solar cell module is large, and the photoelectric conversion efficiency of a solar cell module falls. Cause.

  FIG. 22 is a schematic diagram showing a current conduction path when a transparent conductive film is processed and flattened by a laser. As shown in FIG. 22, the resistance value R when the back surface metal electrode layer 15 is brought into contact with the transparent conductive film material melting portion 12 b is expressed by Equation 7.

  In Equation 7, Rtco, Rcont, and Rmetal have the same value in the case of the material and the crystal produced under the same conditions, but the resistance for Rmelt added by processing is added to increase the series resistance in each cell. . As a result, the resistance of the entire module in which the cells are connected in series is increased.

  On the other hand, in the present embodiment, the current conduction path is not processed by providing a flat portion in a region where cells are separated by laser scribing as in the reference “Japanese Patent Laid-Open No. 2010-205892”. The generated current is taken out through a low resistance current path.

  Therefore, in the fourth embodiment, the output characteristics are not deteriorated due to the crystallinity of the surface transparent conductive film 12 where the back surface metal electrode layer 15 and the surface transparent conductive film 12 are in contact with each other. Is obtained.

Embodiment 5 FIG.
An external lamination region and an inspection region are formed in a region adjacent to the end of the thin film solar cell C electrically connected in series, and the back electrode layer side bus bar electrode 22 provided on this region is a back metal electrode. It may be connected to the layer 15. FIG. 23: is sectional drawing which shows typically schematic structure of the thin film solar cell module concerning Embodiment 5 of this invention. In the separation process of the cells C by laser scribing, if the structure is symmetrical in the series connection direction of the cells C, a thin film solar cell module in which two submodules SM are connected in parallel inside the thin film solar cell module is obtained. It can be produced. The submodule SM is a thin film solar cell module according to the third embodiment. That is, a plurality of external lamination regions and inspection regions are formed in a region between adjacent thin film solar cells C electrically connected in series and a region adjacent to an end portion of the thin film solar cells C electrically connected in series. Has been.

  In this structure, the central portion of the cells C in the series connection direction serves as an arrangement portion for the back electrode layer side bus bar electrode 22 and also serves as a connector portion for connecting the sub modules SM in parallel. Further, the vicinity of the center portion and the vicinity of both end portions in the serial connection direction of the cells C on the translucent insulating substrate 11 are flat portions.

  By processing the lower part of the back electrode layer side bus bar electrode 21 with laser scribing to form a predetermined inspection pattern, the region of the electrical characteristics and optical characteristics can be made similar to the case of the first to fourth embodiments. Can be used for inspection. In the case of this structure, since flat portions are formed in the vicinity of the center portion and in the vicinity of both end portions in the series connection direction of the cells C on the light-transmitting insulating substrate 11, the central portion and the peripheral portion of the large light-transmitting insulating substrate 11 Both can be inspected, and in-plane variation (in-plane uniformity) in the translucent insulating substrate 11 in each manufacturing process can be inspected. Further, by providing a plurality of similar structures, two or more parallel circuits can be configured.

  The structure as described above can be applied to either the case where the light-transmitting insulating substrate 11 is provided with an uneven structure or the case where the surface transparent conductive film 12 is provided with an uneven structure.

  As described above, the thin-film solar cell module according to the present invention is useful for easily managing the manufacturing process and manufacturing good power generation characteristics with good reproducibility.

DESCRIPTION OF SYMBOLS 1 Non-photoelectric conversion area | region 2 Measurement pattern element 3 Metal electrode layer 10 Thin film solar cell module 11 Translucent insulated substrate 12 Surface transparent conductive film 12a Transparent conductive film material crystal | crystallization part 12b Transparent conductive film material fusion | melting part 13 Photoelectric conversion layer 14 Back surface transparent Conductive film 15 Back surface metal electrode layer 21 Front surface electrode layer side bus bar electrode 22 Connector / back surface electrode layer side bus bar electrode 22 Back surface electrode layer side bus bar electrode 31 Separation groove 41 Measurement probe 51 Initial transparent conductive film scribing mark 52 Semiconductor layer scribing mark 53 Back surface metal electrode layer scribe mark 54 Late transparent conductive film scribe mark 55 Late transparent conductive film scribe mark (cell separation groove)
61 Incident light 62 Reflected light 63 Measuring instrument C Cell SM Submodule Z0 Average line Zi Measuring point

Claims (12)

On the translucent insulating substrate, a plurality of thin-film solar cells including a surface transparent conductive film, a photoelectric conversion layer composed of a semiconductor layer, and a back metal electrode in this order are provided, and one of the adjacent thin-film solar cells The thin-film solar battery module in which the back-surface metal electrode of the thin-film solar battery cell and the surface transparent conductive film of the other thin-film solar battery cell are connected and the thin-film solar battery cells are electrically connected in series. ,
An outer laminated region in which the same laminated structure as the thin-film solar cell is formed in a flat region outside the formation region of the thin-film solar cell on the translucent insulating substrate;
A part of the outer laminated region includes an inspection region separated from other regions in the outer laminated region by a separation groove reaching the translucent insulating substrate from the upper surface of the back surface metal electrode,
A thin-film solar cell module. An extraction electrode electrically connected to the surface transparent conductive film of the thin film solar cell at one end among the plurality of thin film solar cells connected in series is formed on the inspection region. Being
The thin film solar cell module according to claim 1. In the inspection region, there is another separation groove that reaches the light-transmissive insulating substrate from the upper surface of the back surface metal electrode and divides the photoelectric conversion layer and the back surface metal electrode in the inspection region into a plurality of small regions. Being formed,
The thin film solar cell module according to claim 1 or 2. A method of manufacturing a thin film solar cell module in which a plurality of thin film solar cells having a surface transparent conductive film, a photoelectric conversion layer composed of a semiconductor layer, and a back metal electrode layer in this order are electrically connected in series on a translucent insulating substrate Because
The surface transparent conductive film, the photoelectric conversion layer, and the back metal electrode layer are stacked on the light-transmitting insulating substrate in a region where the thin-film solar cell is formed, and each thin-film solar cell is separated and the electric A first step of forming a plurality of thin film solar cells connected in series in the formation region of the thin film solar cells;
Forming an outer laminated region in which the same laminated structure as the thin film solar cell is formed in a flat region outside the forming region of the thin film solar cell on the translucent insulating substrate, and a part of the outer laminated region; A second step of forming an inspection region separated from other regions in the outer laminated region by forming a separation groove reaching the translucent insulating substrate from the upper surface of the back surface metal electrode;
A third step of electrically measuring and evaluating the inspection area;
The manufacturing method of the thin film solar cell module characterized by including. The second step is performed in the same step as the first step;
The manufacturing method of the thin film solar cell module of Claim 4 characterized by these. The first step includes a concavo-convex processing step of processing the surface of the translucent insulating substrate or the surface of the surface transparent conductive film formed thereon into a concavo-convex shape,
In the concavo-convex processing step, another region while keeping the surface of the translucent insulating substrate in the region where at least the inspection region is formed in the outer laminated region or the surface of the surface transparent conductive film formed thereon is flat. To process the surface of
The manufacturing method of the thin film solar cell module of Claim 5 characterized by these. The second step includes
Another separation groove reaching the surface transparent conductive film from the upper surface of the back surface metal electrode is formed in the inspection region, and the photoelectric conversion layer and the back surface metal electrode in the inspection region are connected to the first region and the second region. Dividing the process into
Electrically connecting the back surface metal electrode of the first region to the surface transparent conductive film of the first region;
Electrically connecting the back surface metal electrode of the second region to the surface transparent conductive film of the second region;
Have
In the third step, the current flowing between the back surface metal electrode in the first region and the back surface metal electrode in the second region is examined and evaluated.
The manufacturing method of the thin film solar cell module as described in any one of Claims 4-6 characterized by these. The second step includes
Another separation groove reaching the surface transparent conductive film from the upper surface of the back surface metal electrode is formed in the inspection region, and the photoelectric conversion layer and the back surface metal electrode in the inspection region are connected to the third region and the fourth region. Dividing the process into
Electrically connecting the back surface metal electrode of the third region to the surface transparent conductive film of the third region;
Have
In the third step, the current flowing between the photoelectric conversion layer, the surface transparent conductive film, and the back surface metal electrode of the third region from the back surface metal electrode of the fourth region is measured and evaluated,
The manufacturing method of the thin film solar cell module as described in any one of Claims 4-6 characterized by these. In the first step, each of the surface transparent conductive film, the photoelectric conversion layer, and the back metal electrode layer formed in the formation region of the thin film solar cell on the translucent insulating substrate is provided for each thin film solar cell. Including a separation step of separating,
At the beginning of each of the separation steps, a groove having a prescribed shape is formed in the laminated structure of the external lamination region, and the positional relationship between the grooves of the prescribed shape formed in each separation step is inspected, and each subsequent separation step Determining the position condition at
The manufacturing method of the thin film solar cell module as described in any one of Claims 4-8 characterized by these. In the second step, the outer stacked region and the region between the thin film solar cells electrically connected in series and the region adjacent to the end of the thin film solar cells electrically connected in series Multiple inspection areas are formed,
In the third step, electrically measuring and evaluating the plurality of inspection regions;
The method for producing a thin-film solar cell module according to any one of claims 4 to 9. On the inspection region, among the plurality of thin film solar cells connected in series, electrically connected to the surface transparent conductive film or the back metal electrode layer of the thin film solar cell at one end in the outer stacked region. Forming an extraction electrode;
The manufacturing method of the thin film solar cell module as described in any one of Claims 4-10 characterized by these. In the second step, optically measuring and evaluating each layer after forming each layer of the stacked structure formed in the outer stacked region;
The manufacturing method of the thin film solar cell module as described in any one of Claims 4-11 characterized by these.

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