JPS601875A - Solar battery panel - Google Patents

Abstract

PURPOSE:To obtain a solar battery panel having low cost and high reliability and causing no movement of cells even when ethylene vinyl acetate is used as a filler by providing glass fiber group directly above or below strings formed of a plurality of solar battery cells. CONSTITUTION:A filler 21 formed of ethylene vinyl acetate (EVA) sheet, a string in which solar battery cells 3 are connected in series or in parallel, glass fiber group 31 in which two mats of long glass fiber are laminated, a filler 22 formed of EVA sheet, and a back surface material 4 formed of a sheet having polyvinyl fluoride on both sides sandwiched at the intermediate of aluminum foil are laminated as a laminate 14 on one side of a transparent cover glass 1. The glass fiber group is mainly formed of glass fiber having a length of 100mm. or longer.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to solar panels.

[Technical background of the invention]

An example of a solar cell panel is a super straight type solar cell with the goal of low cost and high reliability. An example of the channel will be explained with reference to FIGS. 1 and 2.

That is, a transparent cover glass (11) serves as the structural support for the entire panel, and one side of this cover glass (1) is comprised of solar cells (3) connected in series inside it. A filling material (2) in which strings are embedded is glued. Polyvinyl butyral (hereinafter referred to as PVB) has usually been used as this filling material (2). Filling material (2) A backing material (4) is adhered to the back side of the backside material (4).As shown in FIG.・Vinyl fluoride (
It consists of a three-layer structure of PVF (hereinafter referred to as PVF). This aluminum foil (6) is for preventing water vapor from permeating from the outside. As shown in Figure 1, the periphery of this solar panel is fixed to an aluminum frame (8) that is anodized using an insulating material (force). Butyl rubber is used as a low-cost material that maintains the same properties.

However, in recent years, in order to promote cost reduction and high reliability of solar cell panels, ethylene vinyl acetate (hereinafter referred to as EVA) has been used instead of PvB as the filler (2).
is being developed.

That is, EVA has the following advantages when compared with P'VB.

(1) KVAO's material cost is lower and the current price is comparable to that of PVB. (2) EvA is also simpler in processing the material.

That is, in order to prevent PVBViPVB from adhering itself, a heavy coating is usually applied to the surface and wound into a roll. Therefore, when used in the process of assembling solar cell panels, it is necessary to perform humidity conditioning treatment for about one day after washing with water. On the other hand, EVA can omit the water washing process, and PVB can also handle humidity control.
It's not harsh.

(3) Since EVA bonding is formed through a crosslinking reaction, it has excellent heat resistance and reliability. On the other hand, since PVB is laminated on a principle that does not use a crosslinking reaction, its softening property against temperature is reversible, and it softens at high temperatures.

In addition, regarding the reliability test items of solar cell panels, please refer to J.
P L (Jet Propulsion Labo
The test items have been proposed by, for example, -40°C, and are being standardized in Japan.
Temperature/humidity cycle test in an atmosphere of ~80℃, RH (relative humidity) 90% or higher; High temperature/humidity test at 80℃, RH 90% or higher; Low temperature test at -40℃; -40℃~80℃ temperature shock test; salt water fog test force under 5% salt water; the purpose is to guarantee the lifespan of the solar panel, which is said to be about 20 years. In order to obtain highly reliable solar cell panels that pass these test items, lamination using EVA requires a single vacuum pumping method using a rubber bag, which is the usual method. It is necessary to use a double vacuum system as shown in Figure 3.

That is, the first chamber (lυ and the second chamber, a2) are surrounded by, for example, a rigid body and separated by a diaphragm (diaphragm) 03, and the valves (Vl) and (V2) are separated from each other by a membrane 03.
) to a vacuum pump (not shown).

The stacked body indicated by diagonal lines containing the solar cells placed in the second chamber 0 is normally constructed as shown in FIG. 4.

In other words, transparent cover glass (11, KVA (2υ) made of tempered white plate glass, etc., solar cell (3
), pvA (23) with backing material (4) stacked in the order or in reverse order.

The bonding process for manufacturing a solar cell panel is, for example, as follows. That is, the first chamber (10°) and the second chamber (
13 was evacuated, and the laminate (1, 41 was evacuated to ICVA (2
1) and (2) are heated in a molten state at a temperature range that does not cause a crosslinking reaction, for example, about 120°C. Next, while keeping the second chamber α2 in vacuum, the first chamber αυ is brought to atmospheric pressure. Then, the laminate Oa is compressed by atmospheric pressure in a vacuum through the diaphragm 0. Next, the EVA is heated to a temperature range where a crosslinking reaction occurs.This temperature is about 150°C. The temperature is maintained at this temperature until the crosslinking reaction is completed, and then, after cooling, the laminate α is taken out.
A solar cell, cell/ξ panel using the EVA filler (2) as shown in a part of the figure is formed, and the bonding process is completed.

[Problems in the background art] However, when using a laminate having the above-mentioned material structure, EVA
Since the solar cells are pressurized in a molten state under vacuum, movement of the solar cells occurs. That is, even if the cells (3) are fixedly set in a desired position by soldering, after bonding, as shown in FIG.
) moves outward. In severe cases, some cells (3) may come out outside the glass plate (1). In order to prevent this outward movement, it is possible to tape the periphery of the laminate 0a, but in this case, the sixth
As shown in the figure, a phenomenon occurs in which the cells (3) in each column move to the center and the cells (3) come into contact with each other. If the cells (3) come into contact with each other, not only will there be problems in appearance, but also a short circuit phenomenon will occur in which the desired electromotive force cannot be obtained as a solar relay.

Furthermore, in order to prevent contact between cells (3) due to movement, a seventh
As shown in the figure, on the back side of cell (3),
In addition to the ribbon lead (c) that electrically connects the cells, a rigid insulator bridge (a) is fixed to the cell (3) using adhesive to maintain a constant distance between adjacent cells in the horizontal direction. It is possible to do so. However, the process becomes complicated due to the large number of bridges (A) and the adhesion work, and even if contact between the cells (3) can be prevented, the entire IJ ring moves after the bonding process. There is a problem. That is, this is a phenomenon in which the cell (3) moves to the vicinity of the end face of the cover glass or comes out to the outside of the glass plate.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a low-cost, highly reliable solar cell panel in which cell movement does not occur even when EVA is used as a filler.

[Summary of the invention]

The present invention includes a transparent cover glass, a filler containing a string of a plurality of solar cells bonded to one side of the transparent cover glass and connected in series or parallel therein, and a back side of the filler. A solar cell panel characterized in that a group of glass fibers is provided at least immediately below or directly above the strings in the filler in a solar cell panel having a back material provided with a In an embodiment, the fiberglass fibers are made of glass fibers with a length of 10 (1+m) or more, the glass fiber groups are formed into a mat shape, and the filler is ethylene vinyl acetate.

[Embodiments of the invention]

Next, an embodiment of the thick +1 battery panel of the present invention will be described with reference to FIG. In the figure, the same reference numerals as in the conventional example indicate the same parts.

That is, a transparent cover glass (1) made of tempered glass with a wall thickness of 3 mm, which serves as the overall structural support, has a wall thickness of 0.8 mm on one side.
Filler 0D solar cell (3
) connected in series or parallel, for example, a glass fiber group made by stacking two long glass fiber mats made by Nippon Sheet Glass Co., Ltd. The following material consists of an EVA sheet with a thickness of 0.8 mm (20 μm thick aluminum foil is sandwiched in the middle, and 25 μm thick PVF on both sides)
A backing material (4) consisting of a sheet having a laminate (14
). In this case, in the actual manufacturing process, they are placed one after another on a transparent cover glass (1).

In other words, it is upside down from FIG.

By the way, as an example of conventional use of glass fiber in a solar cell panel, there is a point of view different from that of preventing cell movement according to the present invention.
Energy Annual Report, ”
Investlgatlon of TestMet
hods, Materials Property
es and Procegs for 5olarC
ell Encapsulatrons” (June
1979) pagelO-1+ and “Final
Report on the Invegtlgat
lon of Propoaed ProeetsSe
quence for the Array Auto
trlILted Assembly Ta5k (A
ug.

1980), page 233. The main purposes of these are a) fixing the distance between the solar cell and the cover glass and relieving stress;

b) Maintaining insulation resistance between the cell and backside material.

C) Serves as an air passage during evacuation.

It is. And as a conclusion in these documents, Craneg
lass 230' is the best, Crane and
It is said to be manufactured by the company.

This Craneglass 230 is a glass nonwoven fabric mainly composed of short glass fibers with a length of several tens of meters or less and hardened with 10% or more of a binder, and the binder component used in the present invention is about several % or less, For example, the length is 2m
It is clearly distinguished from long glass fibers consisting of continuous fibers.

In particular, in Microglass CFG-24, groups of long glass fibers with a length of about 2 m and a thickness of 10 μm intersect at an angle of about 120 degrees, whereas Cranegla! S230 is made of short glass fibers with a length of several tens of millimeters or less that are randomly packed together like Japanese paper.

In this example, along with microglass CFG-24, Cra
A similar experiment was conducted using Neglass 230 (thickness 0.005 inch) as 01) in FIG.

The laminate 011) set as shown in FIG. 8 is pasted together using a double vacuum type pasting apparatus shown in FIG. 3 in the same manner as in the prior art.

A typical schedule for the lamination process is shown in FIG.

That is, first, preliminary vacuum evacuation is performed for 10 minutes, for example. As a result, the degree of vacuum before heating is, for example, 0.05 Torr.
It will be about. Next, start heating.

The temperature increase gradient is, for example, 4°C/min. The temperature at which EVA melts is approximately 85°C, and the crosslinking reaction begins at 1
The temperature is 30°C. When the temperature of the laminate Oa reaches 120° C., the first chamber (11) is returned to atmospheric pressure and the laminate Oa is pressure-bonded in a vacuum. Next, the temperature is increased until it reaches 150°C, and after reaching 150°C, it is held for 20 minutes, for example, in order to sufficiently carry out the crosslinking reaction. Then, after the temperature of the laminate is lowered to, for example, 50° C. or lower, the second chamber (I side) is returned to atmospheric pressure. In this case, the micro glass CF
G-24 and Crameglass 230 suppress the movement of the solar cell (3) and are also compatible with EVA, allowing the string to be bonded without causing bubble defects.

In order to complete the projector as a wall, as shown in Figure 1, the frame is completed using an aluminum frame (8) and an insulating material (for example, butyl rubber).

Microglass CFG-24 and Craneglass
Table 1 shows the results of a high-temperature, high-humidity test conducted as a reliability test for solar cell panels using 230.

The conditions were 80° C., RH 90%, and the time was 500 hours.

That is, when using microglass, it performed well in the high temperature and high humidity test, whereas Craneglass 23
When 0 was used, a discoloration phenomenon of Craneglass occurred after 168 hours had elapsed.

Next, microglass CFG-24 and Cranegla
Table 2 shows the relationship between the maximum temperature at the time of lamination and the appearance as an initial appearance test before the reliability test using s++230. Note that the maximum temperature was maintained for 20 minutes.

Table 2 shows that when microglass is used, 145°C to 1
While the appearance is good over a temperature range of 60°C,
When using Craneglass, the temperature is about 155°C.
The raneglass starts to change color.

Next, microglass CFG-24 and Cranegla
Table 3 shows the firing experiment of ss230 itself in the atmosphere, that is, the relationship between firing temperature and appearance. However, the holding time is 30 minutes.

Table 3 shows that the softening temperature of glass fiber is about 700'C, and microglass has initial strength as a mat up to about 600'C. On the other hand, Craneglass starts to color at about 150°C and disappears at 500°C, but due to evaporation of the binder and short fibers, its strength decreases and it cannot withstand use.

Figure io shows Craneglass fired at 50°C.
8 shows a solar cell panel in which the laminate (3+) of FIG. 8 is formed and bonded using 230. As can be seen from the figure, along with the occurrence of wrinkles in Crane Glass, the cells (3
) is causing contact between the cells (3). Moreover, FIG. 11 shows a solar cell panel manufactured and assembled using microglass CFG-24. As can be seen from the figure, the spacing between the cells (3) is kept constant and a good nominal is formed.

That is, when a solar cell panel is manufactured using Craneglasg 230, cell movement can be prevented;
On the other hand, because short glass fibers are used and the fibers are fixed by a binder to maintain the strength of the cloth, the amount exceeds the ViIO% of the binder used, which makes reliability tests, especially tests at high temperatures, difficult. This will cause discoloration and deterioration of the solar panel.

On the other hand, when using microglass CFG-24, in addition to being able to prevent cell movement, since long glass fibers are used, a small amount of binder or no binder is required to maintain the strength of the mat. , no deterioration occurs in reliability tests. Moreover, the price of microglass is low, and it is not only possible to produce panels stably, but also to provide low-cost, highly reliable solar cell panels.

In this example, microglass made of a group of long glass fibers was inserted directly under the string to prevent cell movement as shown in FIG. 8, but the filler Qυ shown in FIG. Even when inserted between the photovoltaic cell and the photovoltaic cell (3), movement of the photovoltaic cell can be prevented. In this way, the cell (
When inserted directly above cell (3), if BVA is used as the filler eυ, the difference in refractive index between EVA and glass fiber is small, so the loss due to light reflection directly above cell (3) is almost ignored. can. In addition, a microglass made of a group of long glass fibers may be inserted at least directly above or below the string, and may also be inserted at another location, for example between the cover glass (1) and the filler ■υ, for the purpose of evacuation, etc. Of course.

In addition, in this example, the wall thickness is 0 and 20 mm at the position directly below the string.
Two sheets of mm microglass cFG-24 were used,
This may be one piece, or pieces of other thicknesses may be used.

The length of the long glass fiber group according to this example is about 2 m, and the size of the solar cell and o-nel is about 1210 y.
The length of the short glass fiber used in Craneglass 230 is about 20-30U, but the length of the short glass fiber used in Craneglass 230 is about 20-30U. If there is an order of 100 as the lower limit, it is possible to reduce the binder content to a small amount, and the effects of the present invention are exhibited.

In addition, although the detailed description has been made by taking as an example the case where CFG-24, which is a matte crossed at about 120 degrees, is used as the long glass fiber group according to this embodiment, cloth using long glass fibers, such as Microglass Cloth (trade name) ) (Nippon Sheet Glass YE
H1001, etc.) can be placed under the solar cell to achieve the same effect, that is, to prevent the cell from moving. In addition, YE
H1001 cannot be completely blended with filler materials such as EVA and leaves a cross pattern when used on cells.

Furthermore, the solar cell panel of the present invention has also been tested in other reliability tests such as -40°C to 80°C, RH90%, 50 cycles; low temperature holding test at -40°C; and salt spray test. Other problems such as failures due to the use of fiber groups do not occur.

〔Effect of the invention〕

As mentioned above, according to the present invention, inexpensive EVA can be used as a filler.
It is possible to provide a low-cost, high-quality, highly reliable solar cell panel in which no cell movement occurs even when using the present invention.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the solar panel, Figure 2 is a schematic cross-sectional view of the back material, Figure 3 is a schematic illustration of a double vacuum laminating device, and Figure 4 is a conventional lamination of solar panels. Figures 5 and 6 are explanatory diagrams showing defects in the arrangement of different cells that occur during the manufacturing process of solar cell panels, and Figure 7 is an example of a structure that eliminates defects in the arrangement of cells. 8 is a sectional view showing a laminate of an embodiment of the solar cell panel of the present invention, FIG. 9 is a typical schedule diagram of the bonding process, and FIG. 10 is a crane-glaze
FIG. 11 is an explanatory diagram showing the cell arrangement when using ss, and FIG. 11 is an explanatory diagram showing the cell arrangement when using microglass. 1...Cover glass 2.21.22...Jl.
Material 3...Solar cell 4...Back material 11...
First chamber 12...Second chamber 13...Guia 7 ram 14...Laminated body 26...Bridge 31...Long gas 2 gas fiber group agent Patent attorney Inoue - Power tube 2 Figure 3 Figure 5 Figure 6 Mouthpiece 7 Figure 8 Figure j/4 Figure 9 Double opening (hr) Figure 10 Figure 11

Claims (4)

[Claims] (1) Consisting of multiple solar cells bonded to one side of a cover glass and connected in series or parallel inside) A filler containing an IJ song and a backing material formed on the back side of the filler. 1. A solar cell panel comprising: a group of glass fibers provided at least directly below or directly above the strings in the filler. (2) The solar cell panel according to claim 1, wherein the glass fiber group mainly consists of long glass fibers having a length of 100 mm or more. (3) The solar cell panel according to claim 1, wherein the glass fiber group mainly consists of a long glass fiber mat having a length of 100 mm or more. (4) The solar cell nosenel according to claim 1, wherein the filler is ethylene vinyl acetate.