JP2000150944A - Solar cell module - Google Patents

Abstract

(57) [Problem] To provide a solar cell module capable of realizing insulation between a power generation active portion and a peripheral portion, and furthermore, a frame with high productivity. SOLUTION: At least a part of a transparent electrode layer, an optical semiconductor layer, and a metal layer formed on a light transmitting substrate are separated into a plurality of cells by processing with a light beam, and are electrically integrated with each other. A thin-film solar cell module,
The transparent electrode layer, the optical semiconductor layer, and the metal layer in a peripheral portion of the translucent substrate are mechanically removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art One of the characteristics required for a solar cell module is a dielectric strength characteristic. In general, the withstand voltage characteristics of a solar cell module can be grasped by measuring a withstand voltage between a terminal of the solar cell and a frame.

[0003] Thin-film solar cells are formed by laminating thin films such as a transparent electrode layer, an optical semiconductor layer, and a metal layer. Many of these layers are formed by a gas phase reaction. In the lamination step by reaction, it is difficult to separate the so-called active portion of the solar cell from other portions. In some cases, these layers may extend to the back side of the substrate. In this case, when the frame is attached, the active portion and the frame often have the same potential. Therefore, the conventional thin-film solar cell has a disadvantage that the withstand voltage characteristics are inferior.

In order to avoid such a problem, a laser beam used for patterning at the time of integration is used to electrically connect an active region at the center of the solar cell and a peripheral portion which may be in electrical contact with the frame. There has been proposed a method of separating the data. However, in this method, since the laser beam is condensed and used, the separation width is narrow, and it is difficult to maintain insulation over the entire circumference of the module. Therefore, the reliability such as the production yield is low and the productivity is low, so that this technology cannot be used industrially.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a solar cell module capable of realizing insulation between a power generation active portion and a peripheral portion, and furthermore, a frame with high productivity. The purpose is to provide.

Another object of the present invention is not only to have excellent dielectric strength characteristics, but also to prevent deterioration in characteristics due to corrosion after sealing, maintain glass strength, and maintain a stable process and high productivity. An object of the present invention is to provide a solar cell module that can be manufactured by using a solar cell module.

[0007]

According to the present invention, at least a part of a transparent electrode layer, an optical semiconductor layer and a metal layer formed on a light transmitting substrate is processed by a light beam. A thin-film solar cell module separated into a plurality of cells and electrically integrated with each other,
The thin-film solar cell module is provided, wherein the transparent electrode layer, the optical semiconductor layer, and the metal layer in a peripheral portion of the translucent substrate are mechanically removed.

In the thin-film solar cell module of the present invention, the transparent electrode layer, the optical semiconductor layer and the metal layer are mechanically removed by a surface polishing method or a mechanical etching method by spraying fine particles. I can do it. In the latter method, the microparticles used are 100
It is preferable that the particles have a particle size of not more than μm.

The mechanical removal is also performed on the surface of the translucent substrate, and the total of the mechanically removed translucent substrate, the transparent electrode layer, the optical semiconductor layer and the metal layer is removed. The depth is preferably 5 μm to 100 μm, more preferably 10 μm to 25 μm.

The width of the portion to be removed around the light-transmitting substrate is determined by the withstand voltage and the effective area ratio, and is 0.5 mm or more, preferably 0.5 mm to 1 c.
m, more preferably 1 to 5 mm.

In the thin-film solar cell module of the present invention, the transparent electrode layer may be made of tin oxide, zinc oxide, IT
O or the like can be used. As the optical semiconductor layer, a layer containing silicon as a main component, for example, p-type a-Si
C: H layer, i-type a-Si: H layer, and n-type microcrystal S
A stacked structure of i: H layers can be used. Further, as the metal layer, silver, Al, Cr, Ti, a laminate thereof and a metal oxide, or the like can be used.

In the thin-film solar cell module of the present invention configured as described above, the periphery of the active portion composed of a plurality of cells separated and integrated from each other is mechanically removed. High insulation can be maintained over the circumference, and therefore, according to the present invention, a module having high withstand voltage characteristics can be obtained at a high yield.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Various embodiments according to the 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. The solar cell module shown in FIG.
It is manufactured as follows. First, area 92cmx46c
m, a tin oxide film (thickness: 8000) on a glass substrate 1 made of soda lime glass having a thickness of 4 mm by a thermal CVD method.
In order to form Angstrom 2 and integrate a plurality of cells, the tin oxide film 2 was patterned with a laser scriber to form a transparent electrode. Reference numeral 3 indicates a transparent electrode scribe line.

As a patterning method, the substrate 1 is
It was set on a Y table and separated using a Q-switched YAG laser. The operating conditions of the laser were such that the second harmonic was 532 nm, the pulse width was 3 kHz, the average output was 500 nw, and the pulse width was 10 nsec. The separation width is 50 μm, and the width of the string (individual solar cell) is about 10
mm.

In order to electrically separate the peripheral part and the solar cell active part over the entire circumference at a position 5 mm from the periphery of the substrate, as shown in FIG. And patterning by laser. Reference numeral 13 indicates the laser isolation line formed thereby.

Further, a region 14 for forming a wiring for taking out an electrode using a solder-plated copper foil is left outside the strings 11a and 11b at both ends with a width of 3.5 mm.

The tin oxide thus patterned
On the film 2, the plasma CVD chamber of the separation-type apparatus is placed.
And an a-Si layer 4 is formed by a plasma CVD method.
Was. That is, at 200 ° C., a p-type a-SiC: H semiconductor layer,
i-type a-Si: H semiconductor layer and n-type microcrystalline Si: H
A) a semiconductor layer is sequentially deposited to form a PIN junction;
—Si layer 4 was formed. To form each layer, the flow rate
Are 100sccm, 500sccm, 100s respectively
ccm SiH_FourUsing p-type and n-type semiconductor layers
To form 1000ppm hydrogen dilution
Of B_TwoH₆And PH _ThreeWas mixed at 2000 sccm.

Further, 30 sc is used for forming the p-type semiconductor layer.
cm ₄ of CH ₄ was mixed to form a carbon alloy. The input power for forming each layer is 2
The power was 00 W, 500 W, and 3 kW, and the reaction pressure was 1 torr, 0.5 torr, and 1 torr, respectively. The thicknesses of the formed layers are estimated to be 150 angstroms, 3200 angstroms, and 300 angstroms, respectively, from the film forming time.

After each layer is formed in this manner, the substrate 1 is set on an XY table and the Q switch YA
Using the G laser, the a-Si layer 4 was patterned by being shifted to the left by 100 μm from the patterning position of the SnO ₂ layer 2 by 100 μm. The operating conditions of the laser were such that the second harmonic was 532 nm, the pulse width was 3 kHz, and the average output was 500.
mw and a pulse width of 10 nsec. The separation width was set to 100 μm by shifting the focal position. Reference numeral 5 indicates a semiconductor scribe line.

Then, by magnetron sputtering,
A ZnO layer (not shown) having a thickness of 1000 angstroms was formed on the patterned a-Si layer 4 by RF discharge using a ZnO target. The sputtering conditions were as follows: argon gas pressure 2 mtorr, discharge power 200
W, the film formation temperature was 200 ° C.

Next, a metal electrode layer 6 having a thickness of 2000 Å was formed on the ZnO layer by DC discharge and room temperature by using an Ag target of the same magnetron sputtering apparatus. The sputtering conditions were an argon gas pressure of 2 mtorr and a discharge power of 200 W.

Finally, the substrate 1 is taken out of the magnetron sputtering apparatus, set on an XY table, and
Ag layer and a-Si using switched YAG laser
By patterning the layer 4, the semiconductor scribe lines 5 to 1
Back electrode scribe lines 7 were formed at positions separated by 00 μm. The operating conditions of the laser were exactly the same as the processing conditions of the a-Si layer 4. The separation width is 70 μm, and the string width is about 10 mm.

As in the case of the tin oxide film 2, in order to electrically separate the peripheral portion and the solar cell active portion over the entire circumference at a position 5 mm from the periphery of the substrate, a processing portion for string separation is additionally provided. Was patterned by laser. The division width was 150 μm, and processing was performed so as to cover the separation portion 13 of the tin oxide film 2.

Next, the outside of the patterning line is set to 0.
The outer portion 15 of 5 mm is extended over the entire circumference by X-
Polishing was performed at a depth of about 25 μm using a Y stage and a uniquely-developed polishing machine having plane rotating teeth capable of fine adjustment in the Z-axis direction. That is, the metal electrode layer 6, the ZnO layer,
The entire thickness of the a-Si layer 4 and the tin oxide film 2 were removed, and the surface of the glass substrate 1 was removed. The processing speed was 3.5 μm / min.

Thereafter, a bus bar electrode 16 made of a solder-plated copper foil was formed at the wiring position 14 described above, and wiring for taking out the electrode was performed. This electrode 16 is parallel to the string.

In order to modularize the cell constructed as described above, a protective film 8 made of an EVA sheet and a fluorine-based film is covered and sealed with a vacuum laminator, filled with a silicone resin 9, and The terminals were formed and framed.

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 measured characteristics of the solar cell were 1240 m short-circuit current.
A, the open-circuit voltage was 44.2 V, the fill factor was 0.68, and the maximum output was 37.3 W.

Next, both the plus and minus electrodes of the take-out terminal were electrically short-circuited, 1500 V was applied between the terminal and the frame, and the resistance value was measured. It was confirmed that the value was 100 MΩ or more.

Finally, after the module was immersed in water for 15 minutes, the above-mentioned resistance was measured.
It was confirmed that it was MΩ or more.

Example 2 After laser patterning of the back metal layer, the transparent conductive film layer, the semiconductor layer, the back metal layer, and the substrate surface around the substrate were removed using a mask and a blast cleaning machine instead of a polishing machine. Except for the above, a solar cell module was manufactured and the same test was performed in the same manner as in Example 1.

A SUS plate was used as a mask, the average particle size of the blast was about 40 μm, and the peripheral portion was mechanically etched by manual operation. The obtained characteristics are almost the same as those in Example 1, except that the short-circuit current is 1240 mA and the open-circuit voltage is 4
4.2 V, fill factor 0.68, and maximum output 37.3 W. Further, the resistance value between the extraction terminal and the frame was 100 MΩ or more before and after immersion.

Comparative Example A solar cell module as shown in FIG. 2 was fabricated in exactly the same manner as in Example 1 except that the transparent conductive film layer, the semiconductor layer, the back surface metal layer, and the substrate surface around the substrate were not removed. Then, a similar test was performed.

The characteristics of the obtained solar cell are as follows:
It was 40 mA, the open circuit voltage was 43.1 V, the fill factor was 0.68, and the maximum output was 36.3 W, which was not much different from Examples 1 and 2. However, the resistance value between the take-out terminal and the frame was 800 kΩ before water immersion and 15 kΩ after water immersion, which was considerably lower than those in Examples 1 and 2.

According to the results of the examples of the present invention, the insulation resistance value between the frame and the terminal is 100 MΩ or more, and it can be seen that this value is also cleared by the immersion test. On the other hand, in a comparative example not according to the present invention, although sufficient current-voltage characteristics were obtained for a solar cell, the result was greatly inferior to the present example in terms of insulation resistance.

[0036]

As described above in detail, according to the present invention, a thin-film solar cell module having excellent withstand voltage characteristics can be obtained with a very simple process at a high yield.

[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 cross-sectional view of a thin-film solar cell module according to a comparative example.

FIG. 3 is a plan view of the thin-film solar cell module shown in FIGS. 1 and 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Glass substrate 2 ... Tin oxide film 3 ... Transparent electrode scribe line 4 ... a-Si layer 5 ... Semiconductor scribe line 6 ... Metal electrode layer 7 ... Backside electrode scribe line 8 ... Protective film 9 ... Silicone resin 11a, 11b ... Both ends String 12: String separation processing part 13: Laser insulation separation line 14: Wiring part 15: Polishing part 16: Busbar electrode

Claims (6)

[Claims] A transparent electrode layer formed on a light-transmitting substrate;
A thin film solar cell module in which at least a part of the optical semiconductor layer and the metal layer is separated into a plurality of cells by processing with a light beam and electrically integrated with each other, in a peripheral portion of the translucent substrate, The thin-film solar cell module, wherein the transparent electrode layer, the optical semiconductor layer, and the metal layer are mechanically removed. 2. The thin-film solar cell module according to claim 1, wherein the transparent electrode layer, the optical semiconductor layer, and the metal layer are mechanically removed by a surface polishing method. 3. The method according to claim 1, wherein the transparent electrode layer, the optical semiconductor layer and the metal layer are mechanically removed by a mechanical etching method by spraying fine particles of 100 μm or less. The thin-film solar cell module according to the above. 4. The mechanical removal of the light-transmitting substrate, the transparent electrode layer, the optical semiconductor layer, and the metal layer, which are also performed on the surface of the light-transmitting substrate. The thin-film solar cell module according to claim 2, wherein the total depth is 5 μm to 100 μm. 5. The total depth of the light-transmitting substrate, the transparent electrode layer, the optical semiconductor layer, and the metal layer mechanically removed is 10 μm to 25 μm. Or the thin-film solar cell module according to 3. 6. The thin-film solar cell module according to claim 1, wherein said optical semiconductor layer contains silicon as a main component.