JP4432236B2 - Thin film solar cell - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
This invention relates to thin film solar cells.
[0002]
[Prior art]
Currently, clean energy research and development is underway from the standpoint of environmental protection. Among them, solar cells are attracting attention because their resources (sunlight) are infinite and pollution-free. A typical example of a solar cell (photoelectric conversion device) in which a plurality of solar cell elements formed on the same substrate are connected in series is a thin film solar cell.
[0003]
Thin-film solar cells are expected to become the mainstream of solar cells in the future because they are thin and lightweight, inexpensive to manufacture, and easy to increase in area, and are attached to roofs and windows of buildings in addition to power supply. Demand is also expanding for commercial and general residential use.
[0004]
Conventional thin-film solar cells have used glass substrates, but research and development of flexible solar cells using plastic films are being promoted in terms of weight reduction, workability, and mass productivity. Furthermore, the thing using the film substrate which carried out the insulation coating to the flexible metal material is also developed. Taking advantage of this flexibility, mass production became possible by a roll-to-roll method or a stepping roll method.
[0005]
In the above thin film solar cell, a first electrode (hereinafter also referred to as a lower electrode), a photoelectric conversion layer comprising a thin film semiconductor layer, and a second electrode (hereinafter also referred to as a transparent electrode) are laminated on a flexible electrically insulating film substrate. A plurality of photoelectric conversion elements (or cells) thus formed are formed. By repeating electrically connecting the first electrode of a certain photoelectric conversion element and the second electrode of the adjacent photoelectric conversion element, the first electrode of the first photoelectric conversion element and the second electrode of the last photoelectric conversion element Can output the voltage required for For example, in order to obtain an alternating current of 100 V as a commercial power source by alternating current with an inverter, the output voltage of the thin-film solar cell is desirably 100 V or higher, and actually several tens or more elements are connected in series.
[0006]
Such a photoelectric conversion element and its series connection are formed by forming an electrode layer and a photoelectric conversion layer, patterning each layer, and a combination procedure thereof. An example of the configuration and manufacturing method of the solar cell is described in, for example, Japanese Patent Application Laid-Open No. 10-233517 and Japanese Patent Application No. 11-19306.
[0007]
FIG. 4 shows an example of the thin film solar cell described in the above-mentioned Japanese Patent Application Laid-Open No. 10-233517, wherein (a) is a plan view, and (b) is a sectional view taken along lines ABCD and BQC in (a). Yes, (c) shows an EE cross-sectional view in (a).
[0008]
A first electrode layer, a photoelectric conversion layer, and a second electrode layer are sequentially laminated on a long film substrate made of an electrically insulating and flexible resin, and a third electrode layer is formed on the opposite side (back surface) of the film substrate. The fourth electrode layer is laminated to form a back electrode. The photoelectric conversion layer is, for example, an amorphous silicon pin junction. As the film substrate material, a polyimide film, for example, a film having a thickness of 50 μm is used.
[0009]
As the material for the film, polyethylene naphthalate (PEN), polyethersulfone (PES), polyethylene terephthalate (PET), or an aramid film can be used.
[0010]
Next, the outline of the manufacturing process will be described below.
[0011]
First, using a punch in the film substrate, a connection hole h1 is opened, and silver is formed to a thickness of, for example, 100 nm by sputtering as a first electrode layer on one side (front side) of the substrate. Similarly, a silver electrode is formed on the surface (the back side) as the third electrode layer. The first electrode layer and the third electrode layer overlap with each other on the inner wall of the connection hole h1, and are electrically connected.
[0012]
As the electrode layer, in addition to silver (Ag), a metal such as Al, Cu, Ti or the like may be formed by sputtering or electron beam evaporation, or a metal oxide film and a metal multilayer film may be used as the electrode layer.
[0013]
After the film formation, on the front side, the first electrode layer is laser processed into a predetermined shape, and the lower electrodes 11 to 16 are patterned. Adjacent portions of the lower electrodes l1 to l6 form one separation line g2, and two separation lines g2 are formed for separation between the two series-connected photoelectric conversion elements and the peripheral conductive portion f. The electrodes l1 to l6 are surrounded by a separation line. After using the punch again to open the current collecting hole h2, an a-Si layer as a photoelectric conversion layer p is formed on the front side by plasma CVD. A film having a width W2 is formed using a mask, and the same separation line as that of the first electrode layer is formed only between the two-row elements by laser processing.
[0014]
Further, a transparent electrode layer (ITO layer) is formed on the front side as the second electrode layer. However, a mask is applied between the two element rows and on both side edges of the substrate parallel to the element row so as not to form the film in the connection hole h1, and the film is formed only on the element part. As the transparent electrode layer, in addition to ITO (Indium Sulfoxide), an oxide conductive layer such as SnO 2 or ZnO can be used.
[0015]
Next, a silver electrode is formed as a fourth electrode layer on the entire back surface. By forming the fourth electrode, the second electrode and the fourth electrode overlap with each other on the inner wall of the current collecting hole h2, and are brought into conduction. On the front side, separation lines having the same pattern as the lower electrode are formed by laser processing to form individual second electrodes u1 to u6, and on the back side, the third electrode and the fourth electrode are simultaneously laser processed to provide connection electrodes e12 to e56. In addition, the power extraction electrodes o1 and o2 are individualized, the separation line g2 is formed so as to overlap the front-side separation line g3 at the periphery of the substrate, and a single separation line is formed between the adjacent electrodes.
[0016]
In addition, in order to process the connection electrode on the back surface with a low-power laser, the material of the fourth electrode is often made a material having a relatively low reflectance. Ni, ITO, Cu, or the like is used as a low reflectance material.
[0017]
There is a separation line g3 at the periphery that encloses all the thin-film solar cell elements in a lump and the adjacent boundary between the two rows of series-connected solar cell elements (inside the peripheral conductive part f). There are no layers in the separation line g3. On the back side, there is a separation line g2 (inside the peripheral conductive portion f) at the peripheral edge that encloses all the electrodes together and at the adjacent boundary of the two rows of series connection electrodes. There are no layers in the separation line g2.
[0018]
In this way, power extraction electrode o1-collection hole h2-upper electrode u1, photoelectric conversion layer, lower electrode l1-connection hole h1-connection electrode e12-upper electrode u2, photoelectric conversion layer, lower electrode l2-connection electrode e23- -The series connection of the photoelectric conversion elements in the order of the upper electrode u6, the photoelectric conversion layer, the lower electrode l6-the connection hole h1-the power extraction electrode o2 is completed.
[0019]
Since the third electrode layer and the fourth electrode layer are electrically at the same potential, in the following description, for convenience of explanation, they may be treated as a single connection electrode layer.
[0020]
FIG. 5 is a perspective view showing a simplified configuration of a thin-film solar cell for easy understanding of the structure. In FIG. 5, the unit photoelectric conversion element 62 formed on the surface of the substrate 61 and the connection electrode layer 63 formed on the back surface of the substrate 61 are completely separated into a plurality of unit units, and are formed by shifting the separation positions. ing. For this reason, the current generated in the photoelectric conversion layer 65 which is an amorphous semiconductor portion of the element 62 is first collected in the transparent electrode layer 66 and then through the current collecting hole 67 (h2) formed in the transparent electrode layer region. And transparent to the element adjacent to the element through a connection hole 68 (h1) for series connection formed in the connection electrode layer 63 and outside the transparent electrode layer area of the element. The lower electrode layer 64 extending to the outside of the electrode layer region is reached, and both elements are connected in series.
[0021]
6 (a) to 6 (g) show a simplified manufacturing process of the thin film solar cell. Using the plastic film 71 as a substrate (step (a)), a connection hole 78 is formed in this (step (b)), and a first electrode layer (lower electrode) 74 and a third electrode layer (connection electrode) are formed on both sides of the substrate. After (part) 73 is formed (step (c)), a current collecting hole 77 is formed at a position away from the connection hole 78 by a predetermined distance (step (d)). Next, the semiconductor layer 75 to be a photoelectric conversion layer and the transparent electrode layer 76 to be the second electrode layer are sequentially formed on the first electrode layer 74 (step (e) and step (f)), and the third A fourth electrode layer (connection electrode layer) 79 is formed on the electrode layer 73 (step (g)). Thereafter, a thin film on both sides of the substrate 71 is separated using a laser beam to form a series connection structure as shown in FIG.
[0022]
In FIG. 6, the connection between the transparent electrode layer 76 and the fourth electrode layer 79 in the current collecting hole h2 is shown in two layers by overlapping each other, but in FIG. 4 and FIG. , Electrically treated as one layer, illustrated as one layer.
[0023]
In the manufacturing process of the thin-film solar cell, the step (b) for forming the connection hole 78 and the step (d) for forming the current collecting hole 77 are performed by punching using a punch (see JP-A-8-139352). . Regarding punching using a punch, the applicant of the present application has proposed a continuous hole forming apparatus with high productivity (see Japanese Patent Application Laid-Open No. 8-139352). The continuous hole processing apparatus includes a substrate transport unit, a through-hole processing unit, and a processing position detection hole processing unit, and the substrate fed from the unwinding roll is sequentially provided with a hole opening unit for detecting a processing position, and a collecting hole. A predetermined number of processing position detection holes, current collecting holes, and connection holes are opened at predetermined positions by the electric hole opening part and the connection hole opening part, cleaned by a cleaning device, and then wound around a winding roll. . Corresponding to the various hole positions, the transport direction and transport distance of the substrate are controlled using the processing position detection hole as a reference.
[0024]
FIG. 7 is a plan view showing an example of the arrangement of the substrate position detection holes h3, the connection holes h1, and the current collecting holes h2. The position detection holes h3 provided in the substrate 1a are opened at predetermined intervals of the predetermined unit pattern of the solar cell and used for positioning the substrate.
[0025]
By the way, in the above, although the example which used the resin film for the board | substrate was mainly demonstrated, it aims at providing the thin film solar cell provided with the heat resistance which can form a semiconductor layer at 400 degreeC or more, and its manufacturing method. A material using a conductive substrate such as metal has been proposed (see Japanese Patent Application No. 11-133647).
[0026]
In the thin film solar cell, a connection hole is formed in a conductive base material, and an electrically insulating layer of a heat-resistant polymer resin is formed on the main surface of the base material and the inner peripheral surface of the connection hole. The first electrode layer of the thin film solar cell is formed on the inner peripheral surface, and the third electrode layer is formed on the back surface of the substrate and the inner peripheral surface of the connection hole, whereby the first electrode layer and the third electrode are connected via the connection hole. Electrically connect the layers. Thereafter, a current collecting hole is formed, and a photoelectric conversion layer and a transparent electrode layer are sequentially formed on the surface side of the substrate on which the first electrode layer is formed and the inner peripheral surface of the current collecting hole. Thereafter, a fourth connection electrode is formed on the back side of the substrate on which the third electrode layer is formed and on the inner peripheral surface of the current collecting hole on which the transparent electrode layer is formed. The four connection electrode layers are electrically connected, but the basic part of the manufacturing method is the same as that described above.
[0027]
[Problems to be solved by the invention]
However, the conventional thin film solar cell and the manufacturing method thereof have the following problems.
[0028]
In a thin-film solar cell using a substrate that transmits laser light, the laser light transmitted through the substrate has a thermal effect on the photoelectric conversion portion on the surface opposite to the connection electrode layer during patterning of the connection electrode layer. There was a problem that a short circuit of a solar cell occurred.
[0029]
In order to solve the above problem, a coloring agent may be added to the substrate to reduce the transmittance of the laser beam and a substrate that absorbs the laser beam may be used. In such a thin film solar cell, the connection electrode layer patterning is also used. In some cases, the colorant of the substrate material that has absorbed the laser beam evaporates, causing a problem of damaging the photoelectric conversion portion on the surface opposite to the connection electrode layer.
[0030]
Furthermore, in order to improve the adhesion between the substrate and the first electrode layer or the third electrode layer, a substrate having a contact area increased by roughening both the front and back surfaces may be used. In many cases, however, there has been a problem of damaging the photoelectric conversion portion.
[0031]
Furthermore, in order to prevent a short circuit due to migration and increase the reliability of the thin film solar cell, the processing line width of the connection electrode layer, that is, the width of the patterning separation groove is increased. In this case, it is necessary to overlap a plurality of laser processing lines. However, when the laser processing lines are overlapped, there is a problem that the photoelectric conversion portion of the overlapped portion is damaged.
[0032]
The present invention relates to a thin-film solar cell using a substrate having the above-described unevenness treatment on the substrate described above, and has been made in order to solve the above-mentioned problems. aims to prevent damage to the thin film to be generated is to provide a thin film solar cell having good solar cell characteristics.
[0033]
[Means for Solving the Problems]
To attain the above object, in the present invention, the first electrode layer serving as a lower electrode layer on a surface of a film substrate made of a tree fat material, a photoelectric conversion layer, sequentially laminated a transparent electrode layer (second electrode layer) And a third electrode layer and a fourth electrode layer as connection electrode layers formed on the back surface of the substrate, wherein the photoelectric conversion unit and the connection electrode layer are shifted in position from each other and a laser is applied to a unit portion. Patterned by a processing method, patterning each other on the surface via a connection hole for electrical series connection formed outside the transparent electrode layer formation region and a current collection hole formed in the transparent electrode layer formation region In the thin film solar cell in which adjacent unit photoelectric conversion portions are electrically connected in series, the substrate has a surface for improving adhesion between the substrate and the first electrode layer or the third electrode layer. and Both sides of the surface treated roughening and that increased contact area, and of the surface or back surface, formed irregularities large contact area larger side face, to form the photoelectric conversion unit.
[0034]
The unevenness treatment is performed by high-frequency plasma etching, but the degree of unevenness differs between the front surface and the back surface of the substrate, and the unevenness increases as the surface faces the high-frequency electrode. Surface contact area is less formed unevenness is small, since the adhesion between the substrate and the thin film electrode layer is weak, probably because easily occurs film peeling, therefore, by adopting the above Symbol onset Ming configuration, It is considered that the problem of causing damage can be suppressed.
[0035]
In addition, as a reference solution relating to the above invention, various means (reference means 1 to 4) for solving the problems described in the above-mentioned section [Problems to be solved by the invention] are described below. These embodiments will be described later as reference examples. First, as a reference means 1 , a photoelectric device in which a first electrode layer as a lower electrode layer, a photoelectric conversion layer, and a transparent electrode layer (second electrode layer) are sequentially laminated on the surface of a film substrate made of a translucent resin material. A conversion unit, and a third electrode layer and a fourth electrode layer as connection electrode layers formed on the back surface of the substrate, wherein the photoelectric conversion unit and the connection electrode layer are displaced from each other by a laser processing method in a unit portion. Patterned and connected to each other on the surface through a connection hole for electrical series connection formed outside the transparent electrode layer formation region and a current collection hole formed in the transparent electrode layer formation region. In the thin film solar cell in which the unit photoelectric conversion portions are connected in series electrically, the material of the first electrode layer and the third electrode layer is at least the single metal or alloy of silver or aluminum, etc. A material having a higher reflectance than the four-electrode layer, and the material of the fourth electrode layer is a material having a reflectance lower than at least the third electrode layer, such as nickel, ITO (indium tin oxide), copper, or the like; The film thickness of the first electrode layer is equal to or greater than the film thickness of the third electrode layer ( reference means 1 ). Further, in the thin film solar cell according to the reference means 1 , the light transmittance with respect to the laser wavelength of the film substrate made of the translucent resin material is set to 60% or more ( reference means 2 ).
[0036]
According to the reference means 1 described above, the fourth electrode layer is made of a material having a low reflectance to improve the laser beam input efficiency, and the film thickness of the first electrode layer is made thicker than that of the third electrode layer. The laser output required for processing of the connection electrode layer can be made lower than that of the first electrode layer, and the first electrode layer can be prevented from being processed by a laser during laser processing of the connection electrode layer. Thereby, the heat influence to a photoelectric conversion part can be suppressed and the problem that film | membrane peeling and the short circuit of a thin film solar cell generate | occur | produce is solved. This is particularly effective in the reference means 2 .
[0037]
Furthermore, in the thin film solar cell using the board | substrate which added the coloring agent to the board | substrate, the following reference means 3 are suitable. That is, a first electrode layer as a lower electrode layer, a photoelectric conversion layer, a transparent electrode layer (second electrode layer) on the surface of a film substrate in which a colorant is added to a resin material to prevent transmission of laser light used for patterning And a third electrode layer and a fourth electrode layer as connection electrode layers formed on the back surface of the substrate, the photoelectric conversion unit and the connection electrode layer being shifted from each other The unit portion is patterned by a laser processing method, and the surface is connected via a connection hole for electrical series connection formed outside the transparent electrode layer formation region and a current collection hole formed in the transparent electrode layer formation region. In the thin-film solar cell in which the unit photoelectric conversion portions that are patterned and adjacent to each other are electrically connected in series, the photoelectric conversion portion is formed on the surface of the substrate on the side having a low colorant concentration.
[0038]
The reason why the reference means 3 is effective is as follows. When adding the colorant to the substrate resin, it is difficult to add the colorant uniformly in the thickness direction of the resin, and the concentration difference of the colorant can be made in the thickness direction of the substrate. As described above, damage to the photoelectric conversion part is caused by evaporation of the colorant of the substrate material that has absorbed the laser light. However, when the first electrode layer is formed on the surface having a high colorant concentration, The first electrode layer formed on the substrate is relatively easily blown off by the vapor of the colorant. Then, the problem which a damage produces can be suppressed by comparing the both surfaces of a board | substrate and forming the photoelectric conversion part containing a 1st electrode layer in the surface where the density | concentration of a coloring agent is low.
[0039]
Further, as described above, the following reference means 4 is suitable as a method for manufacturing a thin film solar cell in which the width of the patterning separation groove is widened. That is, a photoelectric film formed by sequentially laminating a first electrode layer as a lower electrode layer, a photoelectric conversion layer, and a transparent electrode layer (second electrode layer) on the surface of a film substrate made of a resin material or an electrically insulating metal material. A conversion unit, and a third electrode layer and a fourth electrode layer as connection electrode layers formed on the back surface of the substrate, wherein the photoelectric conversion unit and the connection electrode layer are displaced from each other by a laser processing method in a unit portion. Patterned and connected to each other on the surface through a connection hole for electrical series connection formed outside the transparent electrode layer formation region and a current collection hole formed in the transparent electrode layer formation region. In the method of manufacturing a thin film solar cell in which unit photoelectric conversion portions are connected in series, the patterning is a pattern in which a plurality of laser processing lines are stacked to form a patterning separation groove. And training method, the overlapping width dimension of the laser pulse in the laser processing line is less than half the spot diameter of the laser pulse.
[0040]
As will be described later in detail, the reference means 4 can limit the number of times of laser pulse irradiation to 4 pulses or less, and can eliminate damage to the photoelectric conversion unit.
[0041]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings. Reference embodiments 1 to 4 will also be described as reference examples.
[0042]
( Reference Example 1 : Form of reference means 1 and 2 )
Table 1 shows a sample in which a heat-resistant polymer aramid resin having a plate thickness of 25 μm is used for the substrate, and silver is sputter-formed on the substrate as a first electrode layer at a film forming temperature of 300 ° C. This shows the relationship between the laser processing output and the first electrode layer damage when the second harmonic is incident. At this time, the transmittance of the substrate with respect to the laser wavelength was 60%, and the thickness of the first electrode layer was 0.1 to 0.3 μm.
[0043]
[Table 1]
[0044]
From Table 1, it can be seen that the laser processing output at which the first electrode layer damage is generated increases as the first electrode film thickness increases. As will be described later, in order to process and remove the connection electrode layer composed of the third electrode layer (silver 0.2 μm) and the fourth electrode layer (Ni 300 to 500 nm), 0.8 mJ / pulse or more is required. It can be seen that the thickness of one electrode layer is preferably 0.2 μm or more.
[0045]
FIG. 1 is a diagram showing a manufacturing process of a thin film solar cell manufactured based on the above results. Below, the manufacturing method of the thin film solar cell in connection with the reference means 1 is demonstrated using FIG.
[0046]
First, a connection hole h1 was formed in the aramid substrate 10 having a thickness of 38 μm using a punch. On top of that, the first electrode layer L made of a highly reflective metal such as silver is 0.2 μm, and on the opposite main surface, a third electrode layer b of the same material as the first electrode layer is formed with a thickness of 0.2 μm. It formed by the sputtering method. The electrode formation temperature at this time was 300 ° C. As a result of this step, the first electrode layer L and the third electrode layer b were electrically connected through the series connection hole h1.
[0047]
The first electrode layer L was patterned using a second harmonic of a YAG laser and divided into a plurality of units.
[0048]
Thereafter, a current collecting hole h2 is formed by using a punch, and the photoelectric conversion layer a composed of an a-Si layer is formed on the first electrode layer by plasma CVD to be opposite to the transparent electrode layer u on the light incident side and this. A fourth electrode layer e made of nickel having a low light reflectance was sequentially formed on the main surface on the side using a sputtering method. As a result of this step, the transparent electrode layer u and the fourth electrode layer e were electrically connected through the current collection hole h2. The thickness of the fourth electrode layer e is 300 to 500 nm.
[0049]
Finally, the transparent electrode layer u and the photoelectric conversion layer a in the first electrode layer patterning line, and the connection electrode layer composed of the third electrode layer b and the fourth electrode layer e on the opposite side are connected to the second harmonic of the YAG laser. Patterning was performed using waves to form a thin film solar cell in which a plurality of thin film solar cell elements were connected in series.
[0050]
According to this reference example, by setting the first electrode layer thickness to 0.2 μm, it was possible to eliminate the photoelectric conversion portion damage during the connection electrode layer processing.
[0051]
( Reference Example 2 : Form of reference means 3 and examples of the present invention )
Table 2 shows a sample in which 0.2 μm of sputtered silver is formed at a film forming temperature of 300 ° C. as a first electrode layer on a substrate obtained by adding a colorant to a heat-resistant polymer polyimide resin having a thickness of 50 μm. The relationship between the laser machining output and the first electrode layer damage when the second harmonic of the YAG laser is incident from the substrate side is shown. At this time, the transmittance of the substrate with respect to the laser wavelength is 20% or less, and most of the laser light is absorbed by the substrate.
[0052]
[Table 2]
[0053]
From Table 2, it can be seen that the laser processing output at which the first electrode layer damage occurs differs between the front and back of the substrate. This is because it is difficult to uniformly add the colorant to the resin in the thickness direction. When the first electrode layer is formed on the surface where the concentration of the colorant is high, the colorant evaporates due to laser irradiation, and the vapor This is probably because the first electrode layer formed on the substrate blows away.
[0054]
Based on the above results, a thin-film solar cell was manufactured in the same procedure as in FIG. 1 using a 38 μm thick polyimide substrate to which a colorant was added. However, in this case, unlike the first reference example, the film thickness of the first electrode layer need not be equal to or greater than the film thickness of the third electrode layer.
[0055]
Thereby, the photoelectric conversion part damage at the time of a connection electrode layer process was able to be eliminated.
[0056]
In this reference example (reference means 3) , the use of the front and back of the substrate related to the colorant concentration difference in the substrate thickness direction has been described. Similarly, the same effect as this reference example can be obtained by forming the photoelectric conversion portion on the surface which is difficult to receive damage.
[0057]
( Reference Example 3 : Form of reference means 4 )
FIG. 2 shows a plan view of a thin film solar cell related to the reference means 4 , and FIG. 3 schematically shows an overlay image of connection electrode layer laser processing lines.
[0058]
FIG. 2 is a plan view of a thin film solar cell in which three 7 series thin film solar cells are formed in parallel on a heat resistant polymer substrate. FIG. 2A shows the surface on which the photoelectric conversion portion is formed, and FIG. 2B shows the back surface on which the connection electrode layer is formed. 2, the same members or the same functional parts as those in FIG.
[0059]
As shown in FIG. 2A, in this thin film solar cell, the photoelectric conversion layer a formed on the first electrode layer is divided into three regions by the separation part s, and the transparent electrode layer u is , Are formed in three regions on the photoelectric conversion layer a. These three transparent electrode formation regions are power generation regions. 2B, the connection electrode layer e is divided into three regions by the separation portion s, and the extraction electrodes t are connected to the connection electrode layers at both ends, respectively. In FIG. 2, the separation portion s has a wide patterning separation groove, and employs a patterning method in which a plurality of laser processing lines are stacked to form a patterning separation groove.
[0060]
In reference means 4 , as shown in FIG. 3, in order to prevent a short circuit of the connection electrode due to migration or the like, three laser processing lines having a width of 0.2 μm are overlapped to form a connection electrode layer patterning width of 0.4 μm. The overlapping width of the laser pulses constituting the laser processing line at this time is 0.1 μm, which is half of the laser spot diameter, and is the same as the overlapping width of the laser processing lines.
[0061]
Thus, when the overlapping width of the laser pulses and the overlapping width of the laser processing lines is less than or equal to half of the laser spot diameter, the laser pulse irradiated to the connection electrode layer laser processing portion can be reduced to four pulses or less.
[0062]
Next, the manufacturing process of the thin film solar cell of the reference means 4 is demonstrated. In this reference means 4 , an aramid resin having a film thickness of 20 μm was used for the substrate, and the connection hole h1 was formed on the aramid substrate 1 using a punch. On top of that, a first electrode layer made of a highly reflective metal such as silver was formed with a thickness of 0.2 μm, and a third electrode layer was formed with a thickness of 0.2 μm on the opposite main surface by sputtering. The electrode formation temperature at this time was 300 ° C. As a result of this step, the first electrode layer and the third electrode layer were electrically connected through the series connection hole h1.
[0063]
The first electrode layer was patterned using the second harmonic of a YAG laser and divided into a plurality of units.
[0064]
Thereafter, a current collecting hole h2 is formed by using a punch, and a photoelectric conversion layer made of an a-Si layer is formed on the first electrode layer by a plasma CVD method to form a transparent electrode layer on the light incident side and an opposite side thereof. A fourth electrode layer made of indium oxide having a low light reflectivity was sequentially formed on the main surface by sputtering. As a result of this step, the transparent electrode layer and the fourth electrode layer were electrically connected through the current collecting hole h2.
[0065]
Finally, the above-described method is applied to patterning the connection electrode layer composed of the transparent electrode layer and the photoelectric conversion layer in the first electrode layer patterning line, and the third electrode layer and the fourth electrode layer on the opposite side. A thin film solar cell in which a plurality of thin film solar cell elements were connected in series was formed.
[0066]
As described above, by reducing the number of times of laser pulse irradiation to 4 pulses or less, it was possible to reduce damage to the photoelectric conversion portion that occurred during laser patterning of the connection electrode layer.
[0067]
【The invention's effect】
According to the present invention, as described above, the photoelectric conversion formed by sequentially laminating the first electrode layer, the photoelectric conversion layer, and the transparent electrode layer (second electrode layer) as the lower electrode layer on the surface of the film substrate made of the resin material. And a third electrode layer and a fourth electrode layer as connection electrode layers formed on the back surface of the substrate, and the photoelectric conversion portion and the connection electrode layer are shifted from each other and patterned into a unit portion by a laser processing method. And adjacent to each other by patterning on the surface through a connection hole for electrical series connection formed outside the transparent electrode layer formation region and a current collection hole formed in the transparent electrode layer formation region. In the thin-film solar cell in which unit photoelectric conversion portions are electrically connected in series, the substrate has both front and back surfaces for improving adhesion between the substrate and the first electrode layer or the third electrode layer. Uneven Processing is assumed that increased the contact area, and of the surface or back surface, the surface of the formed irregularities larger contact area is large side, by forming the photoelectric conversion unit, when the laser patterning The thin film solar cell which has the favorable solar cell characteristic can be provided by preventing damage to the generated thin film.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a method for manufacturing a thin film solar cell according to an embodiment and a reference example of the present invention. FIG. 2 is a diagram showing an example of a method for manufacturing a thin film solar cell according to a different reference example of the present invention. 3] Schematic diagram of superposition image of laser processing lines according to different reference examples of the present invention. [FIG. 4] A diagram showing an example of the configuration and manufacturing method of a conventional thin film solar cell. [FIG. FIG. 6 is a perspective view showing a schematic configuration of a conventional thin film solar cell. FIG. 7 is a plan view showing an example of the arrangement of position detection holes, connection holes, and current collecting holes in a conventional substrate. Figure [Explanation of symbols]
10: substrate, a: photoelectric conversion layer, b: third electrode layer, e: fourth electrode layer, h1: connection hole, h2: current collecting hole, L: first electrode layer, t: extraction electrode, u: transparent Electrode layer.

Claims (1)

  A first electrode layer as a lower electrode layer, a photoelectric conversion layer, and a transparent electrode layer (second electrode layer) are sequentially laminated on the surface of a film substrate made of a resin material, and formed on the back surface of the substrate. A transparent electrode layer forming region comprising a third electrode layer and a fourth electrode layer as connection electrode layers, wherein the photoelectric conversion portion and the connection electrode layer are shifted from each other and patterned into a unit portion by a laser processing method; The unit photoelectric conversion parts that are patterned and adjacent to each other on the surface are electrically connected in series through a connection hole for electrical series connection formed outside and a current collection hole formed in the transparent electrode layer formation region. In the thin film solar cell formed by connecting, the substrate has an uneven surface on both the front and back surfaces to increase the contact area in order to improve the adhesion between the substrate and the first electrode layer or the third electrode layer. Let City and the surface or inside of the back surface, the surface of the formed irregularities are often large contact area side, the thin-film solar cell, characterized in that the formation of the photoelectric conversion unit.

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