JP2001036105A - Solar battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar battery module which can produce high operation voltage output and is highly reliable. SOLUTION: This solar battery module comprises a plurality of integrated element groups 3 and 4 on a board 1 having an insulating surface. Each group 3 or 4 includes a plurality of photovoltaic elements 2 series-connected electrically to each other. The groups 3 and 4 are laid out in parallel with each other via a separating portion 5 and electrically series-connected to each other. The width of the portion 5 located between adjacent groups 3 and 4 is determined according to a potential difference generated between the adjacent elements 2 which interpose the portion 5 therebetween.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell module capable of outputting a high voltage.

[0002]

2. Description of the Related Art At present, a photovoltaic power generation system using a solar cell is a clean power supply system, and is widely used in home power supply systems and the like.

FIG. 7 is a system schematic diagram showing a general configuration of such a residential photovoltaic power generation system. A plurality of solar cell modules 101 are installed on the roof of the house, and DC outputs from the plurality of solar cell modules 101 are integrated and introduced into the junction box 102. The DC output from the connection box 102 is converted into an AC output by an inverter 103, and is supplied to a domestic load 10 via a distribution board 104.
5 is supplied. The home load 105 is also configured to be supplied with power from the commercial power system 106. If the power supplied from the solar cell module 101 is insufficient such as at night, the commercial power system 106 Is supplied with power.

[0004] Since the home load 105 is normally 100V, the AC output from the inverter 103 is also adjusted to 100V. In order to set the AC output of the inverter 103 to 100 V in this manner, the operating voltage of the solar cell module 101 input to the inverter 103 becomes Preferably, the voltage is set to about 200V. Generally, in the case of a solar cell module using single crystal silicon, since the operating voltage per one sheet is about 50 V, usually 4 to
Five solar cell modules are connected in series to form a set, and an operating voltage of about 200 V output from the set of solar cell modules is input to the inverter 103.

It is known that a solar cell module using an amorphous semiconductor represented by amorphous silicon has a high degree of freedom in output design and can take out an arbitrary output voltage on a single substrate. ing. For example, as a structure of a solar cell module having a high output voltage, the structure shown in FIGS. 1 to 3 is known (Japanese Utility Model Laid-Open No. 6-60155).
1 is a plan view, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG. 3 is a sectional view taken along line BB in FIG.

Referring to these drawings, reference numeral 1 denotes a substrate made of a light-transmitting material such as glass or plastic and has an insulating surface, and 2 denotes a photovoltaic element formed on the substrate 1. . The photovoltaic element 2 is made of SnO ₂ , ITO or Z
a first electrode 11 made of a light-transmitting material such as nO, a photoelectric conversion layer 12 made of an amorphous semiconductor and having a pin junction in order from the substrate 1 side, and a first electrode 11 made of a highly reflective metal material such as Ag and Al. The two electrodes 13 are stacked.

The adjacent first electrodes 11 are separated by a first electrode separation groove 21 formed by exposing the insulating surface of the substrate 1. The adjacent photoelectric conversion layers 12 are separated from each other by photoelectric conversion layer separation grooves 22 formed by exposing the surface of the first electrode 11. Furthermore, between the adjacent second electrodes 13, the photoelectric conversion layer 12
Are separated by a second electrode separation groove 23 formed by exposing the surface of the second electrode. The second electrode 13 is buried in the photoelectric conversion layer separation groove 22 and is in contact with the first electrode 11, whereby the adjacent photovoltaic elements 2 are electrically connected in series.

Reference numeral 3 denotes a first integrated element group including a plurality of photovoltaic elements 2 electrically connected in series as described above, and reference numeral 4 denotes a plurality of photovoltaic elements similarly connected in series. This is a second integrated device group including the power device 2. These first
Grooves 8 are formed around the integrated device group 3 and the second integrated device group 4.
Is provided to prevent leakage through the first electrode, the photoelectric conversion layer, or the second electrode attached to the side surface of the substrate 1 during formation. The groove 8 is formed by removing the first electrode, the photoelectric conversion layer, and the second electrode.

First integrated device group 3 and second integrated device group 4
Are arranged in parallel via the separation groove 5. This separation groove 5 is also formed by removing the first electrode, the photoelectric conversion layer, and the second electrode in this portion, and exposing the insulating surface of the substrate 1. The directions of the series connection in the first integrated device group 3 and the second integrated device group 4 are opposite to each other. That is, in the first integrated element group 3, the right side of the paper is negative and the left side is positive, whereas in the second integrated element group 4, the left side of the paper is positive and the right side is negative. .

The first and second integrated device groups 3 and 4 are electrically connected in series by a connection line 6, and an electric output is taken out from a pair of positive and negative output terminals 7. For example, a solder-plated copper foil can be used as the connection line 6. The connection line 6 is formed on the first electrode 11 a located at the left end of the first integrated element group 3 on the paper surface and on the paper surface of the second integrated element group 4. The second electrode 13a located at the left end
The top is connected using solder. The positive output terminal 7 is connected to the first electrode 11b located at the right end of the second integrated element group 4 in the drawing, and the negative output terminal 7 is located at the right end of the first integrated element group 3. The second electrode 13b is connected via a lead wire (not shown). Further, the surface of each photovoltaic element 2 is covered with a resin layer 9 having an insulating property.

According to this configuration, since two integrated element groups 3 and 4 are provided, a higher voltage can be output as compared with a case where only one integrated element group is provided. For example, when amorphous silicon is used, the operating voltage of one photovoltaic element is about 0.6 V.
Approximately 6
An output voltage of 0 V can be obtained, and an operating voltage of about 120 V can be obtained by providing two integrated device groups. Further, the structure of the photovoltaic element is changed to a plurality of pins.
With a so-called stacked structure having a junction, the operating voltage of one photovoltaic element can be increased to about 2 V, so that a high operating voltage of about 200 V can be obtained.

Therefore, according to a solar cell module using an amorphous semiconductor, a solar cell module having a high operating voltage of about 200 V or more can be easily obtained.
Therefore, it is not necessary to combine a plurality of solar cell modules to obtain a high voltage as in the related art, and one solar cell module can be directly connected to the inverter.

[0013]

By the way, when the operating voltage of one solar cell module is increased to about 200 V as described above, various problems caused by the high voltage are considered to occur. . However, although it is conventionally known that a high-voltage solar cell module can be obtained by using an amorphous semiconductor as described above, only a device having an operating voltage of about 50 V is actually manufactured. There were no solar cell modules that output extremely high operating voltages.

Accordingly, an object of the present invention is to solve the problem that occurs when the output voltage is increased as described above, and to provide a highly reliable solar cell module that can output a high operating voltage.

[0015]

The solar cell module according to the present invention comprises a plurality of integrated element groups each composed of a plurality of photovoltaic elements electrically connected in series on a substrate having an insulating surface. A solar cell module comprising a plurality of integrated element groups arranged in parallel via a separation unit and electrically connected to each other, wherein the solar cell module is located between the integrated element groups arranged adjacent to each other. The width of the separation portion is determined according to a potential difference generated between the photovoltaic elements adjacent to each other across the separation groove.

Further, when the potential difference is V, the value of the width D of the separating portion is a value satisfying a relationship of D (μm) ≧ 3 × V (V). .

Further, the separation section is characterized in that the insulating surface of the substrate is exposed.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a solar cell module having the structure shown in FIG. 1 was manufactured and subjected to a reliability test. The manufacturing process of the solar cell module will be described with reference to a plan view of each process shown in FIG. In the figure, the parts having the same functions as those in FIG. 1 are denoted by the same reference numerals.

First, in the step shown in FIG.
A SnO ₂ film was formed on the entire surface of the substrate 1 made of 325 mm × 880 mm and 4 mm thick glass by using a thermal CVD method. A wavelength of about 1.06 μm is formed on the outer periphery of the SnO ₂ film.
The YAG laser was applied, and the outer peripheral portion was removed in a frame shape with a width of about 200 μ to form a region to be the groove 8. In forming the groove 8, it is not always necessary to make the groove into a frame shape. The groove 8 may be formed in a grid shape by combining four linear grooves formed in parallel with four sides on the outer peripheral portion of the substrate 1. .

The SnO ₂ in the region corresponding to the separation groove 5
The film was removed with a width of about 200 μ by irradiation with a YAG laser. Further, the SnO ₂ film is irradiated with the YAG laser by about 50 mm at intervals of about 8 mm in a direction orthogonal to the separation groove 5.
The first electrode separation groove 21 is formed by exposing the insulating surface of the substrate 1 so as to form a first electrode separation groove 21.
The electrode 11 was formed. By this process, 10 per row
Zero first electrodes 11 were formed.

Next, in the step shown in FIG. 2B, an amorphous semiconductor film was formed on the entire surface of the substrate 1 so as to cover the first electrode 11. In forming the amorphous semiconductor film, a p-type amorphous silicon carbide layer having a thickness of about 100 °, an intrinsic amorphous silicon layer having a thickness of about 1000 °, and a an n-type amorphous silicon layer, a p-type amorphous silicon layer having a thickness of about 100 °,
An intrinsic amorphous silicon germanium layer having a thickness of about 1700 ° and an n-type amorphous silicon layer having a thickness of about 200 ° were laminated in this order to form a so-called laminated structure. According to such a configuration, an operating voltage of about 1 V can be obtained for one photovoltaic element.

On the first electrode 11, the wavelength 0.5 nm is applied to the amorphous semiconductor film along the first electrode separation groove 21.
By irradiating the second harmonic of a 3 μm YAG laser to melt and remove the amorphous semiconductor film, a photoelectric conversion layer separation groove 22 was formed and a plurality of photoelectric conversion layers 12 were formed. At this time,
A portion corresponding to the first integrated device group 3 and a portion corresponding to the second integrated device group 4 are irradiated with laser light by shifting the first electrode separation grooves 21 by 50 μm in opposite directions to each other. The porous semiconductor film was melted away.

Further, in the step shown in FIG. 3C, an Ag film was formed on the entire surface of the substrate 1 including the photoelectric conversion layer 12 by sputtering. In such a step, the Ag film is buried in the photoelectric conversion layer separation groove 22 and comes into contact with the first electrode 11. Then, in the region of the groove 8 and the separation groove 5 formed by removing the SnO ₂ film, A
The g film was irradiated with laser light to completely remove the Ag film and the photoelectric conversion layer 12 in this region, exposing the insulating surface of the substrate 1. When the Ag film and the photoelectric conversion layer are removed in the region of the groove 8, it is not always necessary to remove the Ag film and the photoelectric conversion layer in a frame shape, and the removal may be performed in a groove shape only in a direction parallel to the series connection direction (left-right direction in the drawing). . Further, a YAG laser was used to remove a region corresponding to the groove 8, and a second harmonic of the YAG laser was used to remove a region corresponding to the separation groove 5.

Further, on the photoelectric conversion layer 12, the Ag film is irradiated with the second harmonic of the YAG laser along the photoelectric conversion layer separation groove 22, and the Ag film is melted and removed in the form of a second line.
An electrode separation groove 23 is formed, and a plurality of second electrodes 13 are formed.
Was formed. At this time, the portions corresponding to the first integrated type element group 3 and the portions corresponding to the second integrated type element group 4 are irradiated with laser light shifted 50 μm in opposite directions to the photoelectric conversion layer separation grooves 22 respectively. , And the Ag film was removed by melting.

The connection line 6 made of a solder-plated copper foil
The first electrode 11a located at the left end of the first integrated element group 3 as shown in FIG. 2 and the second electrode 13a located at the left end of the second integrated element group 4 shown in FIG. Connected.
The connection electrode 6 can be formed by a printed electrode using a conductive resin or the like.

Further, a resin layer 9 is formed by providing a thermoplastic resin sheet such as an EVA sheet over the entire surface of the substrate 1 by vacuum thermocompression bonding, and the terminal box 6 is provided with the first electrode 11b and the second electrode 13b located at the right end. Then, the solar cell module having the configuration shown in FIG.

Then, the solar cell module manufactured as described above was placed in an atmosphere at a temperature of 85 ° C. and a humidity of 93% for 10 minutes.
After standing for 00 hours, the photoelectric conversion characteristics were measured.
The characteristics were reduced by 15% to 20% as compared with the characteristics before leaving.

The inventors of the present invention have conducted intensive studies on the reason why the photoelectric conversion characteristics have deteriorated in this way, and have come to speculate the cause as follows.

Referring again to FIG. 1, first integrated device group 3
The second integrated device group 4 is assumed to be composed of n photovoltaic devices 2. Here, the k-th photovoltaic element from the right end in the first integrated element group 3 is a
Then, (nk) photovoltaic elements exist on the left side of the photovoltaic element a. The photovoltaic element adjacent to the photovoltaic element a with the separation groove 5 interposed therebetween is denoted by b. This photovoltaic element b is a photovoltaic element constituting the second integrated element group 4, and (n-
k) There will be photovoltaic elements. Therefore,
The potential difference between the photovoltaic elements a and b is 2 (nk) v, where v is the voltage per photovoltaic element.
Becomes That is, a potential difference of 2 (nk) times the voltage per element is generated between the elements a and b.

As described above, the operating voltage per stacked photovoltaic element made of an amorphous semiconductor is at most 1
Just a V. Therefore, in order to suppress current leakage between adjacent photovoltaic elements, it was sufficient to separate these photovoltaic elements by a groove of about 50 μm as shown in the above-described manufacturing process. However, the solar cell module according to the present invention includes two integrated element groups 3 and 4 arranged in two rows in parallel. For this reason, generation of a leak current between the photovoltaic elements constituting the integrated element groups 3 and 4 poses a problem.

For example, the first and second integrated device groups 3 and 4
Is composed of 100 photovoltaic elements each, between the 50th photovoltaic element from the right end in these integrated element groups 3 and 4, 2 (100-5)
0) × 1 = 100 V potential difference occurs. Further, when the operating voltage of the solar cell module is 200 V, a potential difference of as much as 200 V occurs between the photovoltaic elements located at the right ends of the first and second integrated element groups 3 and 4. Since a large potential difference occurs between the photovoltaic elements a and b adjacent to each other with the separation groove 5 interposed therebetween, a leak current occurs between the photovoltaic elements a and b, and the photoelectric It is presumed that the conversion characteristics were reduced.

Therefore, in order to solve such a problem, the present inventors manufactured a solar cell module having the configuration shown in FIG. 1 by changing the width of the separation groove 5 variously, and conducted a reliability test. FIG. 5 shows the characteristic diagram obtained as a result. The abscissa in the figure is the width of the separation groove 5, and the ordinate is the yield although the rate of decrease in the photoelectric conversion characteristics after the reliability test was 5% or less.
The operating voltage of the module is set to 100V.

As shown in FIG. 5, when the operating voltage of the module was 100 V, the yield could be improved to 95% or more by setting the width of the separation groove 5 to 300 μm or more. When the operating voltage of the entire module is doubled or tripled, the width of the separation groove is doubled or tripled to equalize the electric field applied between the opposing photovoltaic elements across the separation groove. And the generation of a leak current through the separation groove can be suppressed.

When the operating voltage of the entire module is 100 V, for example, in the solar cell module having the configuration shown in FIG. 1, the photovoltaic element located at the right end of the first integrated element group 3 and the second integrated element group 4 And a photovoltaic element located at the right end of the device has a potential difference of 100 V. Therefore, from the results of FIG. 5, the yield can be improved by setting the width of the separation groove provided between these photovoltaic elements to 300 μm. Similarly, when the potential difference between the two photovoltaic elements is 200 V, the width of the separation groove 5 between the two photovoltaic elements may be set to 600 μm, and when a potential difference of 300 V occurs, the separation is performed. The width of the groove may be 900 μm.

That is, assuming that a potential difference between two adjacent photovoltaic elements is V (V), the width D (μm) of the separation portion between the two photovoltaic elements is expressed by the following equation (1). By satisfying the value, it is possible to suppress the leakage current generated between the two photovoltaic elements.

[0036]

(Equation 1)

As described above, in a solar cell module having a plurality of integrated element groups arranged in parallel, in order to suppress the occurrence of leakage current between the integrated element groups,
The width of the separating portion provided between these integrated element groups may be determined so as to satisfy Formula 1 according to the largest potential difference among the potential differences generated between the photovoltaic elements adjacent to the separating portion. For example, in the case of a solar cell module that includes two integrated element groups arranged in two rows in parallel and outputs an operating voltage of 200 V, the width of a separating part provided between the two integrated element groups is determined by changing the width of the separating part. The width may be 600 μm or more so as to satisfy Equation 1 in accordance with 200 V, which is the maximum potential difference among the potential differences between the adjacent photovoltaic elements.

For example, in the case of a solar cell module including three integrated element groups arranged in three rows in parallel and outputting an operating voltage of 300 V, the operating voltage of one integrated element group is 100 V. Therefore, the width of the separation portion provided between the integrated element groups is set to the largest potential difference among the potential differences generated between the photovoltaic elements adjacent to the separation portion.
Depending on V, the width may be 300 μm or more so as to satisfy Equation 1.

Further, the width of the separation portion provided between each integrated element group is not necessarily required to be constant. For example, FIG.
As shown in the plan view, the width of the separation portion is small in a portion where the potential difference generated between the photovoltaic elements facing each other across the separation portion is small, and the width of the separation portion is wide in a portion where the potential difference is large. good.

The width of the separation groove may be any as long as it satisfies the relationship of Equation 1 as described above. However, if the width is too large, the effective area is reduced and the photoelectric conversion characteristics are reduced. The attachment may be determined as appropriate.

[0041]

As described above, the width of a separation groove provided between a plurality of integrated element groups arranged in parallel is determined according to the potential difference generated between photovoltaic elements facing each other with the separation groove interposed therebetween. are doing. Therefore, generation of a leak current through the separation groove can be suppressed, and a solar cell module with improved reliability can be provided.

[Brief description of the drawings]

FIG. 1 is a plan view of a solar cell module for high voltage.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a sectional view taken along line BB in FIG. 1; .

FIG. 4 is a plan view for explaining steps for manufacturing the solar cell module of FIG. 1;

FIG. 5 is a characteristic diagram showing a relationship between a width of a separation groove and a yield.

FIG. 6 is a plan view of another solar cell module according to the present invention.

FIG. 7 is a system schematic diagram of a photovoltaic power generation system.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Photovoltaic element, 3 ... 1st integrated element group,
4 Second integrated device group, 5 Separation groove, 6 Connection line, 7
Output terminal, 8 ... groove

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shinichi Miyahara 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. F-term (reference) 5F051 AA05 BA03 BA11 BA17 EA01 EA05 EA09 EA10 EA11 EA16 EA17 GA03

Claims (3)

[Claims] 1. A plurality of integrated element groups each comprising a plurality of photovoltaic elements electrically connected in series to each other on a substrate having an insulating surface, and the plurality of integrated element groups are separated by a separating unit. A solar cell module arranged in parallel and electrically connected to each other via a plurality of integrated element groups, wherein a width of the separation portion located between the integrated element groups arranged adjacently sandwiches the separation groove. Wherein the photovoltaic module is determined according to a potential difference generated between the adjacent photovoltaic elements. 2. When the potential difference is V, the value of the width D of the separation portion satisfies the following relationship: D (μm) ≧ 3 × V (V). The solar cell module according to claim 1. 3. The isolation section according to claim 1, wherein the insulating surface of the substrate is exposed.
The solar cell module as described.