JP2001044454A - Integrated thin-film solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an integrated thin-film solar cell module which is superior in manufacturing yield and long-term reliability, even if elements are separated by laser scribing. SOLUTION: A surface electrode 2, a semiconductor thin-film photoelectric conversion layer 3, and a back electrode 4 are successively laminated on a substrate 1. The layers 2, 3 and 4 are separated into solar cells along separating grooves, which are rectilinear and parallel with each other and running vertical to the long side of the substrate 1, and the thin-film photoelectric conversion layer 3 is equipped with a layer, which partially contains at least partially silicon other than amorphous silicon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an integrated thin-film solar cell module, and more particularly to an integrated thin-film solar cell module having a plurality of solar cells separated by laser scribe.

[0002] In this specification, the terms "polycrystalline", "microcrystalline" and "crystalline" mean not only a perfect crystalline state but also a state partially including an amorphous state. It shall be.

[0003]

2. Description of the Related Art FIGS. 4 and 5 are a plan view and a partially cutaway perspective view schematically showing the structure of a conventional integrated thin-film solar cell module.

Referring to FIGS. 4 and 5, in a conventional integrated thin-film solar cell module, a surface electrode layer 102 made of a light-transmitting conductive thin film is formed on a light-transmitting insulating substrate 101 such as glass. , A semiconductor thin film photoelectric conversion layer 103 including a semiconductor junction such as a pin junction, and a back electrode layer 104 made of an appropriate metal are sequentially formed.

The surface electrode layer 102 is divided into a plurality by a plurality of surface electrode separation grooves 102a extending linearly in parallel with each other in the long side direction of the substrate 101. The semiconductor thin film photoelectric conversion layer 103 is divided into a plurality by a plurality of connection opening grooves 103a extending linearly in parallel with each other in the long side direction of the substrate 101. The back electrode layer 104 is electrically connected to the front electrode layer 102 through the connection opening 103a. The semiconductor thin-film photoelectric conversion layer 103 and the back electrode layer 104 are divided into a plurality by a plurality of back electrode separation grooves 104a extending linearly in parallel with each other in the long side direction of the substrate 101.

As described above, on one substrate 101, a plurality of solar cells 105 are formed corresponding to the plurality of divided photoelectric conversion layers 103. These solar cells 1
The surface electrode layer 102 of an arbitrary cell 05 is connected to the back electrode layer 1 of an adjacent cell 105 via the connection opening groove 103a.
The plurality of solar cells 105 are electrically connected in series and integrated by being electrically connected to the cell 04.

The front electrode separation groove 102a, the connection opening groove 103a, and the back electrode separation groove 104a are each formed by laser scribe. Conventionally, the laser scribe has been performed in the long side direction of the substrate 101 for the following reason.

(1) The movement path of the laser in the laser scribe is as shown in FIG. In the case of scribing in the long side direction, the number of direction change parts S of the movement route (solid line in the drawing) can be reduced as compared with the case of scribing in the short side direction. Therefore, as compared with the case of scribing in the short side direction of the substrate 101, the moving distance of the laser can be shortened by 2 × (long side length−short side length). Therefore, the process time can be shortened slightly.

(2) When dusts of the same size adhere to the module, the larger the unit cell area is, the smaller the effect of the output drop due to the shadow effect is.

(3) Normally, as shown in FIG. 7, the current extracting lead wire 106 is attached along the scribe line 104a. Therefore, the contact area between the lead wire 106 and the transparent electrode can be increased, and the effect of the resistance loss of the transparent electrode may be reduced.

[0011]

In a conventional integrated thin-film solar cell module, scribing is performed in parallel to the long side direction of the module. Therefore, when a thick silicon layer such as crystalline silicon is formed, However, there was a problem that the yield and long-term reliability at the time of manufacturing decreased. Hereinafter, this will be described.

In FIG. 5, when the photoelectric conversion layer 103 made of silicon is manufactured under low temperature and high hydrogen dilution conditions, FIG.
As shown in (1), a particularly large warp (W2) occurs in the long side direction of the substrate 101. This is because hydrogen (H) is taken into the photoelectric conversion layer 103 to generate a compressive stress in the photoelectric conversion layer 103, and the substrate 101 and the photoelectric conversion layer 103 have different amounts of thermal expansion. Conceivable.

Further, the warp increases as the thickness of the photoelectric conversion layer 103 formed on the substrate 101 increases.
Therefore, when the photoelectric conversion layer 103 includes crystalline silicon, the warpage in the longitudinal direction is particularly remarkable. This is because, in consideration of the absorption coefficient of crystalline silicon, the thickness of crystalline silicon needs to be slightly less than one order to two orders of magnitude thicker than amorphous silicon in order to absorb sunlight sufficiently.

If laser scribing is performed in parallel with the long side direction in a state where a large warp has occurred, it becomes difficult to adjust the laser focus. For example, in FIG. 8, when focusing is performed on the center portion C in the module long side direction, the focus is greatly shifted at both end portions E. This laser focus shift causes laser damage to the surface electrode layer 102 and conversely, scribes of the photoelectric conversion layer 103 become insufficient. Furthermore, in a state in which a large warpage has occurred, the photoelectric conversion layer 103 is easily peeled off by a long-term heat cycle due to residual stress, and the long-term reliability of the module is reduced. As a result, the yield and long-term reliability at the time of manufacturing the module decrease.

SUMMARY OF THE INVENTION An object of the present invention is to provide an integrated thin-film solar cell module which is excellent in yield and long-term reliability at the time of manufacturing even when element separation is performed by laser scribe.

[0016]

In an integrated type thin film solar cell module according to one aspect of the present invention, a first electrode layer, a semiconductor thin film photoelectric conversion layer, and a second
The electrode layers are separated in a direction perpendicular to the long side of the substrate by a plurality of separation grooves that are linear and parallel to each other to form a plurality of solar cells, and the semiconductor thin film photoelectric conversion layer is at least partially non-conductive. It has a power generation layer containing silicon other than crystalline silicon.

In the integrated thin-film solar cell module according to one aspect of the present invention, the solar cells are separated in a direction perpendicular to the long side direction (that is, in the short side direction). Since the warp in the short side direction is smaller than that in the long side direction, it is possible to suppress the deviation of the focus during laser scribing. For this reason, even when the power generation layer contains non-amorphous silicon which needs to be thickened, damage to the solar cell due to a focus shift can be reduced, and the yield and long-term reliability during module manufacturing can be reduced. Performance can be improved.

The term "non-amorphous silicon" means a material containing crystalline silicon such as polycrystalline silicon and microcrystalline silicon. The power generation layer means a layer including an i-type photoelectric conversion layer.

In the integrated thin-film solar cell module according to another aspect of the present invention, the first electrode layer, the semiconductor thin-film photoelectric conversion layer, and the second electrode layer, which are sequentially stacked on the substrate, have a plurality of linearly parallel layers. A plurality of solar cells are formed by being separated in the vertical direction and the long side direction of the substrate by the separation groove, and the substrate has a thickness of 4.0 mm or less, and the semiconductor thin film photoelectric conversion layer has a thickness of 1.0 μm or more. Having a thickness of

In the integrated thin-film solar cell module according to another aspect of the present invention, the solar cells are separated in the short side direction as in the first aspect. For this reason, even when a thin film photoelectric conversion layer as thick as 1.0 μm or more is formed, the yield and long-term reliability at the time of manufacturing the module can be improved.

In the first and other aspects, preferably, the ratio of the dimension in the long side direction to the dimension in the short side direction of the substrate is 4/3 or more.

The present invention is particularly suitable for a substrate having such dimensions, since the amount of warpage in the short side direction is particularly smaller than the amount of warpage in the long side direction.

In the first and other aspects, preferably, the semiconductor thin film photoelectric conversion layer is formed at a temperature of 550 ° C. or lower by a plasma CVD (Chemical Vapor Deposition) method.

Thus, an inexpensive material such as glass can be used for the substrate. In the first and other aspects, preferably, the substrate is glass.

Thus, the module can be manufactured at low cost.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 are a plan view and a partially cutaway perspective view schematically showing the configuration of an integrated thin-film solar cell module according to an embodiment of the present invention.

Referring to FIGS. 1 and 2, in the integrated thin-film solar cell module according to the present embodiment, a front electrode layer 2, a semiconductor thin-film photoelectric conversion layer 3, and a back electrode layer 4 Are sequentially laminated.

When a light-transmitting insulating substrate such as glass or transparent resin is used as the substrate 1, usually, a light-transmitting oxide conductive material is used as the front electrode layer 2, and a metal material is used as the back electrode layer 4. . The light-transmitting oxide conductive material used for the surface electrode layer 2 includes SnO ₂ , ITO, Zn
A material composed of at least one selected from O and the like can be used. The metal material used for the back electrode layer 4 is, for example, Ti, Cr, Al, Ag, Au, C
A layer made of at least one metal selected from u and Pt or an alloy thereof can be used.

The front and back electrode layers 2,
The specific material as the light-transmitting oxide conductive material or metal material for No. 4 is not particularly limited, and can be appropriately selected from known materials and used.

The semiconductor thin film photoelectric conversion layer 3 is a material containing silicon other than amorphous, such as crystalline silicon such as polycrystal and microcrystal, hydrogenated crystalline silicon, crystalline silicon carbide, and crystalline silicon. In addition to nitrides, crystalline silicon alloys containing carbon, germanium, tin and the like can also be used. Further, a material in which valence control is performed by adding a p-type or n-type dopant element to these various semiconductor materials may be used. further,
As the type of the semiconductor junction of the semiconductor thin film photoelectric conversion layer 3, a pin type, a nip type, or the like, or a tandem type in which these types are appropriately combined and stacked can be used.

In this embodiment, the solar cells 5 are separated in a direction perpendicular to the long side direction of the module (that is, in the short side direction). That is, the surface electrode layer 2 is formed of a plurality of linear surface electrode separation grooves 2 parallel to each other in the short side direction of the module.
The semiconductor thin-film photoelectric conversion layer 3 is divided into a plurality by a plurality of connection opening grooves 7 extending linearly in parallel with each other in the short side direction of the module. The layer 3 and the back electrode layer 4 are divided into a plurality by a plurality of back electrode separation grooves 4a extending linearly in parallel with each other in the short side direction of the module.

As described above, a plurality of solar cells 5 are formed on one substrate 1 in correspondence with the plurality of photoelectric conversion layers 3. The front electrode layer 2 of any of these solar cells 5 is electrically connected to the back electrode layer 4 of the adjacent cell via the connection opening groove 3a. Thus, a plurality of solar cells 5 are electrically connected in series and integrated on the substrate 1.

The substrate 1 has a thickness of 4.0 mm or less, and the semiconductor photoelectric conversion layer 3 has a thickness of 1.0 μm or more. Further it is preferred that the ratio of the dimension L _A in the long side direction with respect to the short side dimension L _B of the modules is 4/3 or more, and a longitudinal dimension L _A module is not less than 300 mm.

The semiconductor thin-film photoelectric conversion layer 3 is preferably formed by a plasma CVD method at a temperature of 550 ° C. or less, and the substrate 1 is preferably made of glass.

In this embodiment, the solar cells 5 are separated in the short side direction of the module. As shown in FIG. 3, the amount of warpage W1 in the short side direction is smaller than the amount of warpage W2 in the long side direction as shown in FIG. 8, so that the focus shift during laser scribing can be suppressed to a small value.
Therefore, even when a silicon layer other than an amorphous silicon layer is formed thick, damage to the solar cell 5 due to a shift in focus can be reduced, and the yield at the time of manufacturing a module and the reliability can be improved. it can.

In FIGS. 3 and 8, illustration of the surface electrodes 5 and 105 is omitted for convenience of explanation.

[0038]

Embodiments of the present invention will be described below.

(Example of the Present Invention) A pin type polycrystalline silicon solar cell was manufactured as follows.

First, dimensions 400 × 300 mm, thickness 3 m
First, a SnO ₂ film was formed as a surface electrode by a CVD method on a blue sheet glass substrate having a m and a linear expansion coefficient of 8.5 × 10 ⁻⁶ K ⁻¹ . Subsequently, laser scanning was performed using a YAG laser so as to be parallel to the short side of the substrate, and separation by scribing of SnO ₂ was performed. The unit cell width when scribing is 10
mm.

Next, the substrate was moved to a silicon film forming chamber, and the p-type microcrystalline silicon layer was 6 nm thick, the non-doped polycrystalline silicon layer was 2.8 μm, and the n-type microcrystalline silicon layer was 7 nm. And pi
An n-junction component was formed. The film formation temperature at this time is set to 250
° C. Thereafter, each silicon layer forming the pin junction component was laser-scanned using a YAG laser so as to be parallel to the short side of the substrate, and separated by scribing.

Further, a ZnO film as a back electrode
A 300 nm thick Ag film and a 10 nm thick Ti film were formed by sputtering. Finally, the silicon layers and the back surface electrodes were separated by scribing using a YAG laser again to obtain an integrated solar cell. Further, EVA (Ethylene-Vinyl Acetate Copolymer) and a fluorine-based resin sheet were laminated on the back surface to obtain a solar cell module.

At this time, the production yield after each step (production of 50 sheets) was as follows.

[0044]

[Table 1]

The average value of the output characteristics of the non-defective module was 17.5 V in open voltage (38 stages in series) and 0.61 in short-circuit current.
A, the fill factor was 0.70, and the output was 7.5 W.

After completion of the module, a heat cycle test (100 ° C. → −40 ° C., 200 cycles) was carried out using 10 samples, but no change in appearance such as a decrease in output characteristics or peeling of the film was found.

Comparative Example A pin-type polycrystalline silicon solar cell was manufactured. Dimensions 400 × 300mm, thickness 3mm,
A solar cell module was fabricated on a blue plate glass substrate having a linear expansion coefficient of 8.5 × 10 ⁻⁶ K ⁻¹ by using substantially the same steps as in the above-described present invention.

However, laser scribing was performed so that the front electrode, each silicon layer and the back electrode were parallel to the long side of the substrate.

At this time, the production yield after each step (production of 40 sheets) was as follows.

[0050]

[Table 2]

The average value of the output characteristics of the non-defective module is as follows: open voltage 12.9 V (28 stages in series), short circuit current 0.82 V
A, the fill factor was 0.67, and the output was 7.1 W. A heat cycle test (100 ° C. → −40 ° C., 200 cycles) was performed using 10 samples after completion of the module. As a result, in one sample, slight peeling was observed around the laser scribe line, and the output was about 6%. Dropped.

[0052]

As described above, in the integrated thin film solar cell module of the present invention, the solar cells are separated in the short side direction. Since the warp in the short side direction is smaller than that in the long side direction, it is possible to suppress the deviation of the focus during laser scribing. For this reason, it is possible to reduce the damage of the solar cell due to the focus shift,
The yield and long-term reliability at the time of manufacturing the module can be improved.

[Brief description of the drawings]

FIG. 1 is a plan view schematically showing a configuration of an integrated thin-film solar cell module according to an embodiment of the present invention.

FIG. 2 is a partially broken perspective view schematically showing a configuration of an integrated thin-film solar cell module according to one embodiment of the present invention.

FIG. 3 is a diagram illustrating warpage in a short side direction.

FIG. 4 is a plan view schematically showing a configuration of a conventional integrated thin-film solar cell module.

FIG. 5 is a partially broken perspective view schematically showing a configuration of a conventional integrated thin-film solar cell module.

FIG. 6 is a diagram showing a laser scan path in laser scribe.

FIG. 7 is a diagram showing an arrangement state of a current extraction lead wire.

FIG. 8 is a view showing warpage in a long side direction.

[Explanation of symbols]

1 substrate, 2 surface electrode layer, 2a surface electrode separation groove, 3
Semiconductor thin film photoelectric conversion layer, 3a connection opening groove, 4 back electrode layer, 4a back electrode separation groove, 5 solar cell,
10 Integrated thin-film solar cell module.

Claims (5)

[Claims] A first electrode layer, a semiconductor thin-film photoelectric conversion layer, and a second electrode layer, which are sequentially stacked on the substrate, are formed by a plurality of linear and parallel separation grooves; An integrated thin-film solar cell module comprising a plurality of solar cells by being separated into a plurality of layers, and wherein the semiconductor thin-film photoelectric conversion layer has a power generation layer containing silicon other than amorphous in at least a part thereof. 2. The method according to claim 1, wherein the first electrode layer, the semiconductor thin film photoelectric conversion layer, and the second electrode layer, which are sequentially stacked on the substrate, are arranged in a direction perpendicular to the long side of the substrate by a plurality of linear and parallel separation grooves. An integrated thin-film solar cell, wherein the substrate has a thickness of 4.0 mm or less, and the semiconductor thin-film photoelectric conversion layer has a thickness of 1.0 μm or more. module. 3. The integrated thin-film solar cell module according to claim 1, wherein a ratio of a dimension in a long side direction of the substrate to a dimension in a short side direction of the substrate is 4/3 or more. 4. The semiconductor thin-film photoelectric conversion layer has a temperature of 550 ° C.
The integrated thin-film solar cell module according to any one of claims 1 to 3, which is formed by a plasma CVD method at the following temperature. 5. The substrate according to claim 1, wherein said substrate is glass.
The integrated thin-film solar cell module according to any one of the above.