JP3243232B2 - Thin film solar cell module - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thin-film solar cell module used for photovoltaic power generation.

[0002]

2. Description of the Related Art Thin-film solar cell modules include a first electrode layer made of a transparent conductive oxide and a laser scribing on a light-transmitting substrate, a semiconductor layer made of an amorphous silicon and the like, a laser scribing, and a metal. It is manufactured by forming a thin film such as a second electrode layer (backside electrode) and laser scribing, and sealing the entire surface of each layer with a resin filler and a protective film or a protective material.

Since the above-mentioned layers are formed by a gas phase reaction such as a CVD method or a sputtering method, each layer is formed on the entire surface of the light-transmitting substrate. The laser scribing of each layer is performed to separate each layer into individual solar cells and to connect adjacent solar cells in series (or in parallel).

In such a thin film solar cell module,
When used outdoors, the active part (power generation area) of the solar cell is deteriorated and corroded by the intrusion of moisture from the outside,
The problem is that the power generation characteristics deteriorate. One of the causes is that moisture invades from between the substrate at the end of the solar cell module and the filler. Therefore, it is required to prevent the intrusion of moisture from the end of the solar cell module to improve the weather resistance.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a thin film solar cell which can be manufactured with high productivity without deterioration of power generation characteristics due to corrosion due to moisture or the like in a state sealed with a filler or the like. To provide modules.

[0006]

A thin-film solar cell module according to the present invention comprises a plurality of solar cell units formed by laminating a first electrode layer, a semiconductor layer, and a second electrode layer, each of which is formed and patterned on a substrate. Are integrated and sealed with a filler, wherein the periphery of the solar cell region is surrounded by a region having a larger adhesive force to the filler than the solar cell region.

In the present invention, a region having a larger adhesive force to the filler than the solar cell region specifically means that the adhesive force to the filler is 3 kgf in vertical peel strength.
/ Cm or more.

In the present invention, such a region having a large adhesive force is, for example, (1) a first region made of a transparent conductive oxide.
Exposed portion of electrode layer, (2) exposed portion of substrate, or (3) C
a metal layer selected from the group consisting of r, W, Mo and Ti.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

The materials used for the thin-film solar cell module of the present invention will be described. As the substrate, a light-transmitting substrate such as glass is used. First electrode layer (transparent electrode layer)
As a material for the material, for example, a transparent conductive oxide such as SnO ₂ , ZnO, or ITO is used. As a material of the semiconductor layer, a layer containing silicon as a main component, for example, p-type a-S
i: H layer, i-type a-Si: H layer, and n-type microcrystal S
A stacked structure of i: H layers is used. Further, a stacked structure of a polycrystalline silicon layer forming a pin junction may be used.
As a material of the second electrode layer (backside electrode layer), Ag, A
l, Cr and Ti, and a laminate of these metals and metal oxides are used.

Each of these layers is separated into individual solar cells by laser scribing with a predetermined width after being formed by a CVD method or a sputtering method, and adjacent solar cells are connected in series (or in parallel). Is done.

As the material of the filler, ethylene-vinyl acetate copolymer (EVA), polyisobutylene, polyvinyl butyral, silicone and the like are used. Further, as the protective film, a vinyl fluoride film or a laminate of a vinyl fluoride film and an aluminum foil is used. As another protective material, a metal plate, a glass woven fabric, or the like may be used.

According to the present invention, by enclosing the periphery of the solar cell region (active portion, power generation region) with a region having a large adhesive force to the filler, and by firmly bonding the substrate and the filler at the peripheral portion, The purpose is to improve the watertightness of the end of the solar cell module.

Here, the adhesive force between the base material and the filler is:
For example, vertical peel strength (JIS K685
4) can be evaluated. Therefore, when the base material is a glass substrate, a transparent conductive oxide such as SnO ₂ forming the first electrode layer, a semiconductor, or a metal forming the second electrode layer, a filler is formed on these base materials as a filler. The vertical peel strength of the adhered EVA was measured. As a result, the peel strength of EVA was the largest of 15 kgf / cm or more when the base was a glass substrate, and was 14 kgf / c equivalent to the above even when the base was a transparent conductive oxide.
m, and 0.5 to 4 when the underlying material is a semiconductor or metal.
It was found to be significantly larger than kg / cm. Further, the peel strength changes remarkably depending on the type and surface condition of the metal. In the case of a high melting point metal such as Cr, Mo, W, and Ti, the change is relatively small. / Cm in many cases.

Therefore, the periphery of the solar cell area has a larger adhesive strength to the filler than the solar cell area, specifically, the adhesive strength to the filler is preferably 3 kgf / cm in vertical peel strength. Is 10kgf /
cm, the watertightness at the end of the solar cell module can be improved and the weather resistance can be improved.

In the present invention, such a region having a large adhesive strength is, for example, (1) a first region made of a transparent conductive oxide.
Exposed portion of electrode layer, (2) exposed portion of substrate, or (3) C
a metal layer selected from the group consisting of r, W, Mo and Ti.

In order to form a region having a large adhesive force by an exposed portion of the first electrode layer made of a transparent conductive oxide, for example, C
A method of mechanically removing the second electrode layer and the semiconductor layer laminated on the peripheral portion of the substrate by a VD method or a sputtering method is used. Specific examples include a surface polishing method and a blast method by spraying fine particles. In the latter method, it is preferable to use fine particles having a particle size of 100 μm or less. Further, the second electrode layer and the semiconductor layer may be removed by irradiating a laser beam having an enlarged beam diameter.

In order to form the region having a large adhesive force by the exposed portion of the substrate, a method of mechanically removing the second electrode layer, the semiconductor layer, the first electrode layer and the substrate itself from the peripheral portion of the substrate is used. In this case, the second electrode layer, the semiconductor layer, the first
The total thickness of the electrode layer and the substrate is preferably 5 to 100 μm, more preferably 10 to 25 μm.

After the first electrode layer or the substrate is exposed as described above, the surface may be further treated with a silane coupling agent.

In order to form a region having a large adhesive strength with a metal layer selected from the group consisting of Cr, W, Mo and Ti, a method of performing a primer treatment using a treatment liquid containing these metal components is used. Alternatively, a method may be used in which a mask is formed on the active portion of the solar cell and a metal made of Cr, W, Mo or Ti is deposited or sputtered.
In any case, the underlying material is not particularly limited, and a metal made of Cr, W, Mo, or Ti may be formed on the second electrode layer.

The width of the region having a large adhesive strength with the filler at the peripheral edge of the substrate is determined so as to obtain a sufficient adhesive strength, and is 0.5 mm or more, preferably 0.5 mm to 1 cm,
More preferably, it is 1 to 5 mm.

In the thin-film solar cell module of the present invention having the above-described structure, the periphery of the solar cell region is surrounded by a region having a large adhesive force with respect to the filler over the entire periphery, so that the adhesiveness with the filler is high. Can be maintained, and the weather resistance can be improved without deterioration of power generation characteristics due to corrosion due to penetration of moisture or the like.

[0023]

Embodiments of the present invention will be described below.

Embodiment 1 FIG. 1 is a sectional view showing a solar cell module according to one embodiment of the present invention. In FIG. 1, a region near the end of the solar cell module is shown in an enlarged manner. FIG. 2 is a plan view of FIG. The solar cell modules shown in these figures are manufactured as follows.

Thermal CVD is performed on a glass substrate 1 made of soda lime glass having an area of 92 cm × 46 cm and a thickness of 4 mm.
A transparent electrode 2 made of a SnO ₂ film having a thickness of 8000 ° was formed by the method.

The substrate 1 is set on an XY table, and the second harmonic (wavelength: 532 nm) of the Q-switched YAG laser is radiated from a laser scriber at an oscillation frequency of 3 kHz.
The transparent electrode 2 was scribed by irradiating at z, an average output of 500 mW, and a pulse width of 10 nsec. FIG. 1 shows a transparent electrode scribe line 3. At this time, the width of the string (individual solar cell) along the length direction of the substrate 1 was about 10 mm, and the separation width (the width of the transparent electrode scribe line 3) was 50 μm.

Further, in order to electrically separate the peripheral portion of the substrate 1 from the active portion of the solar cell, a distance from the outer periphery of the substrate 1
The laser scribe was applied to the position of mm over the entire circumference. FIG. 1 shows an insulation separation line 8.

Next, the substrate 1 is set in a separation type plasma CVD apparatus, and a p-type a-Si: H layer and an i-type aS
An i: H layer and an n-type microcrystalline Si: H layer were sequentially deposited to form an a-Si layer 4 constituting a pin junction. Each of the above Si: H layers was formed at a film formation temperature of 200 ° C. At this time, the p-type a-Si: H layer contains 10% of SiH ₄ .
0 sccm, hydrogen diluted B ₂ H ₆ (1000 ppm)
The reaction pressure was set to 1 torr by supplying 00 sccm and CH ₄ at a flow rate of 30 sccm, and 200 W power was applied to form the film. CH ₄ is included for carbon alloying. The film thickness was adjusted to about 150 ° by adjusting the film forming time. i
For the type a-Si: H layer, the reaction pressure was set to 0.5 torr by supplying SiH ₄ at a flow rate of 500 sccm, and
It was formed by applying a power of W. The film thickness was adjusted to about 3200 ° by adjusting the film formation time. The n-type microcrystalline Si: H layer is made of S
iH ₄ at 100 sccm, hydrogen diluted PH ₃ (1000 pp
m) at a flow rate of 2000 sccm to increase the reaction pressure to 1
The pressure was set to torr and a power of 3 kW was applied to form the film. The film thickness was adjusted to about 300 ° by adjusting the film forming time.

This substrate 1 is set on an XY table, and the second harmonic of a Q-switched YAG laser is oscillated at a frequency of 3 kHz and an average output of 500 from a laser scriber.
Irradiate at a position shifted by 100 μm from the scribing position of the transparent electrode 2 with mW and pulse width of 10 nsec.
The i-layer 4 was scribed. FIG. 1 shows a semiconductor scribe line 5.
Is shown. At this time, the separation width (the width of the semiconductor scribe line 5) is set to 10 by shifting the focal position of the laser beam.
It was set to 0 μm.

Next, the above substrate, a ZnO target and an Ag target were set in a magnetron sputtering apparatus. First, an argon gas pressure was set to 2 mtorr, a film formation temperature was set to 200 ° C., and RF discharge was performed at a discharge power of 200 W to sputter a ZnO target, thereby obtaining 1
A 000 mm thick ZnO layer was formed. Next, an Ag gas pressure was set to 2 mtorr, a film formation temperature was set to room temperature, and a direct current discharge was performed at a discharge power of 200 W to sputter an Ag target, thereby forming a 2000 mm thick Ag layer. Thus, the back electrode 6 in which the ZnO layer and the Ag layer were laminated was formed.

The substrate 1 is set on an XY table, and the second harmonic of a Q-switched YAG laser is oscillated at a frequency of 3 kHz and an average output of 500 from a laser scriber.
Irradiation was performed at a position shifted by 100 μm from the scribing position of the a-Si layer 4 with mW and a pulse width of 10 nsec to scribe the back electrode 6 and the a-Si layer 4. FIG. 1 shows a back electrode scribe line 7. At this time, the separation width (width of the back electrode scribe line 7) was set to 70 μm.

Thereafter, the strings 11a and 11b at both ends are formed.
, A bus bar electrode formation region having a width of 3.5 mm was secured. Further, in order to electrically separate the peripheral portion of the substrate 1 from the active portion of the solar cell, laser scribe was applied to a position 5 mm from the outer periphery of the substrate over the entire periphery. At this time, the separation width was set to 150 μm by shifting the focal position of the laser beam, and processing was performed so as to include the insulating separation line 8 of the transparent electrode 2.

The substrate 1 is set on an XY stage, and the peripheral portion of the substrate 1 (from the insulating separation line 8) is set by using a uniquely-developed polishing machine having plane rotating teeth capable of fine adjustment in the Z-axis direction. Back electrode 6 and a-S
The i-layer 4 was polished to expose the transparent electrode 2 on the periphery of the substrate 1.

Further, a solder layer 9 is formed in the busbar electrode forming region.
And a bus bar electrode 12 made of a plated copper foil 10 were formed, and wiring (not shown) for taking out the electrode was connected. This bus bar electrode 12 is parallel to the string.

The EVA sheet and the protective film 2 are used as the filler 21 on the back surface of the module configured as described above.
As No. 2, a vinyl fluoride film (manufactured by DuPont, trade name: Tedlar) was covered, and the EVA sheet was sealed by heating and melting using a vacuum laminator. After that, terminals were formed and mounted on a frame.

The current-voltage characteristics of the solar cell module thus obtained were measured using an AM1.5 solar simulator of 100 mW / cm ² . As a result, the characteristics of the solar cell were as follows: short-circuit current 1240 mA, open-circuit voltage 44.2 V, fill factor 0.68, maximum output 37.3 W
Met. Next, both the plus and minus electrodes of the extraction terminal were electrically short-circuited, and 1500 V was applied between the terminal and the frame, and the resistance was measured. As a result, it was confirmed that the insulation was 100 MΩ or more and the insulation was good. Furthermore, after this solar cell module was immersed in water for 15 minutes, the resistance was measured in the same manner as described above. As a result, it was confirmed that the solar cell module was also 100 MΩ or more and was well insulated.

Example 2 In the same manner as in Example 1, the steps up to laser scribing of the back electrode 6 and the a-Si layer 6 were performed. After that, a mask made of a SUS plate is provided on the active portion of the solar cell,
An abrasive having an average particle size of about 40 μm was sprayed from a blast cleaner to mechanically remove the chamfered surface of the back electrode 6, the a-Si layer 4, the transparent electrode 2, and the surface of the substrate 1 at the peripheral edge of the substrate 1. Hereinafter, the solar cell module shown in FIG. 3 was manufactured in the same manner as in Example 1. The same measurement as in Example 1 was performed for this solar cell module. As a result, the characteristics of the solar cell were almost the same as those in Example 1, and the short-circuit current 1
240 mA, open circuit voltage 44.2 V, fill factor 0.68,
The maximum output was 37.3W. Further, the resistance value between the take-out terminal and the frame was 100 MΩ or more before and after immersion in water.

Comparative Example A solar cell module was manufactured in the same manner as in Example 1, except that the peripheral portion of the substrate 1 was not mechanically removed.
The same measurement as in Example 1 was performed for this solar cell module. As a result, the characteristics of the solar cell are as follows:
240 mA, open-circuit voltage 43.1 V, fill factor 0.68,
The maximum output was 36.3 W, which was not much different from Examples 1 and 2. However, the resistance between the extraction terminal and the frame is 800 kΩ before immersion in water, and 15 kΩ after immersion in water.
kΩ, which was considerably lower than those of Examples 1 and 2. This is because the adhesive strength of the filler at the peripheral portion of the substrate 1 is small, and water has entered from the filler bonding interface at the edge of the substrate 1.

[0039]

As described above in detail, according to the present invention, a thin film that can be manufactured with high productivity without deterioration of power generation characteristics due to corrosion due to moisture or the like in a state sealed with a filler or the like. A solar cell module can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a thin-film solar cell module according to a first embodiment.

FIG. 2 is a plan view of the thin-film solar cell module of FIG.

FIG. 3 is a cross-sectional view of a thin-film solar cell module according to a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Glass substrate 2 ... Transparent electrode 3 ... Transparent electrode scribe line 4 ... a-Si layer 5 ... Semiconductor scribe line 6 ... Backside electrode 7 ... Backside electrode scribe line 8 ... Insulation separation line 9 ... Solder layer 10 ... Plated copper foil 11a , 11b ... strings at both ends 12 ... busbar electrode 21 ... filler 22 ... protective film

Claims (4)

(57) [Claims] 1. A plurality of solar cells are integrated by laminating a first electrode layer, a semiconductor layer, and a second electrode layer formed and patterned on a translucent glass substrate, respectively, and sealed with a filler. In the solar cell module described above, the entire area around the solar cell area has a width of 0.5 mm or more from a peripheral edge of a main surface of a peripheral end of the translucent glass substrate.
Comprising an electrode layer or an exposed surface of the translucent glass substrate,
Surrounded by a region having a larger adhesive force to the filler than the solar cell region, the filler is provided in the region having a larger adhesive force, and a light beam is provided inside the region having a larger adhesive force by a light beam. A thin-film solar cell module, wherein an insulating separation line for electrically separating a solar cell region from the peripheral end is formed. 2. The thin-film solar cell module according to claim 1, wherein the adhesive strength between the region having a large adhesive strength and the filler is around 3 kg / cm in vertical peel strength. 3. The region having a large adhesive force is Cr, W, M
3. The thin-film solar cell module according to claim 1, comprising a metal layer selected from the group consisting of o and Ti. 4. A thin film according to claim 1, wherein said filler is selected from the group consisting of ethylene-vinyl acetate copolymer, polyisobutylene, polyvinyl butyral and silicone. Solar cell module.