CN111727509B - Solar cell module - Google Patents

Abstract

The solar cell module (100) includes: a plurality of electrically connected solar cell units (10); an encapsulating material (103) that encapsulates the plurality of solar cell units (10); and two opposite masters of the slave solar cell unit (10). The two protective members (105A, 105B) sandwich the packaging material (103) on the surface side. Each solar cell unit (10) is provided with a gas layer (13) between at least one of the two main surfaces and the encapsulating material (103) facing the main surface.

Description

Solar cell module

Technical field

The present invention relates to solar cell modules.

Background technique

As people's awareness of environmental protection increases, their enthusiasm for developing net zero energy houses (ZEH) and net zero energy buildings (ZEB) is also increasing. In order to realize the above-mentioned ZEH and ZEB, the required power must be generated by the building itself. Currently, solar cell modules are being studied as power generation units.

Although solar cell modules are installed on buildings, they cannot provide the required power simply by installing them on the roof of the building. Therefore, installation of solar cell modules in places other than the roof is considered, and technology development in this area is also ongoing. progress. For example, Patent Document 1 describes a solar cell-integrated wall material, and Patent Document 2 describes a mount for installing a solar cell module on a wall surface.

Patent document 1: Japanese Patent Publication No. 2016-186156

Patent document 2: Japanese Patent Publication No. 2016-000949

Contents of the invention

The invention is a solar cell module. The solar cell module includes: a plurality of solar cell units electrically connected; a packaging material that encapsulates a plurality of the solar cell units; and two A protective member, two of the protective members, together with a plurality of the solar cell units, sandwich the packaging material from two opposite main surface sides of the solar cell unit, and each of the solar cell units is located between two of the solar cell units. An air layer is provided between at least one of the main surfaces and the packaging material opposite to the main surface.

Description of drawings

FIG. 1 is a schematic partial cross-sectional view showing a solar cell module according to the embodiment.

2 is a schematic cross-sectional view showing a control principle of controlling reflected light on the surface of a solar cell unit in a conventional solar cell module.

3 is a schematic cross-sectional view showing the situation of reflected light on the surface of a solar cell unit encapsulated by an encapsulating material in a conventional solar cell module.

4 is a schematic cross-sectional view showing how light is reflected on the surface of a solar cell in the solar cell module according to the embodiment.

5 is a schematic cross-sectional view showing an example of roughening the inner surface of a sheet covering the solar cells in the solar cell module according to the embodiment.

6 is a schematic cross-sectional view illustrating one step in the manufacturing method of a solar cell module according to an embodiment.

7 is a schematic partial cross-sectional view showing a solar cell module according to a modification of the embodiment.

Detailed ways

Hereinafter, embodiments and examples will be described with reference to the drawings. The following descriptions of embodiments and examples are examples, and are not intended to limit application objects or uses. In addition, the dimensional ratios of each component in the drawings are set for convenience in illustration and do not represent actual dimensional ratios.

FIG. 1 shows a schematic partial cross-section of a solar cell module 100 (hereinafter simply referred to as "module") according to the embodiment.

The module 100 according to the embodiment includes a solar cell string 10A in which a plurality of solar cells 10 (hereinafter simply referred to as “cells”) are electrically connected via wiring (tab lines) 102 . . The solar cell string 10A (hereinafter simply referred to as "cell string") refers to an electrical connection unit (output unit) in which approximately 15 plurality of battery cells 10 are connected in series, for example.

Using the sealing material 103 formed of the first sealing material 103a and the second sealing material 103b, the upper surface of each battery unit 10 (for example, the surface on the light-receiving side of the two main surfaces of the battery unit 10, that is, the light-receiving surface), and the lower surface are The surface (for example, the main surface on the opposite side to the light-receiving surface, that is, the back surface) and the entire surrounding surface are encapsulated.

In addition, the packaging material 103 is sandwiched between two protective members, namely, the light-receiving surface protective material 105A and the back surface protective material 105B. For example, glass or resin material is used as each protective material 105A, 105B.

The packaging process of the plurality of battery cells 10 using the packaging material 103 (the first packaging material 103a and the second packaging material 103b) can be performed, for example, as follows: the first packaging material 103a is sequentially placed on the light-receiving surface protection material 105A. , the stacked body of the battery cell string 10A, the second packaging material 103b and the back surface protective material 105B is then heated under predetermined conditions to be solidified as the packaging material 103.

In this embodiment, as will be described later, a gas layer 13 is provided between the main surface on the light-receiving side of each battery cell 10 and the first sealing material 103 a. In this way, the color tone of the light-receiving surface of each battery unit 10 appears, and as a result, the module 100 according to the embodiment can control the color tone.

Next, a method of controlling the color tone of each battery cell 10 in the module 100 according to the embodiment will be described with reference to the drawings.

First, the surface of the silicon wafer included in the battery unit 10 has a lower saturation tone such as gray. As shown in FIG. 2 , the outermost layer 11 is formed on the outermost surface of the battery cell 10 using, for example, an antireflection film. In this case, the reflected light Ra from the surface of the outermost layer 11 for incident light is different from the reflected light Ra from the battery cell. The reflected light Rb of the light receiving surface of the wafer 10 (the wafer itself) with respect to the incident light generates interference that reflects the phase difference in the outermost surface layer 11 . As a result, the reflected light Ra and the reflected light Rb mutually enhance or weaken each other depending on the wavelength reflecting the phase difference. That is, the reflected light Ra based on the difference in refractive index between the air and the surface layer 11 and the reflected light Rb based on the difference in refractive index between the surface layer 11 and the light-receiving surface of the battery unit 10 interfere, so that The form of hue appears to the human eye.

The phase difference between the reflected light Ra and the reflected light Rb is controlled by the film thickness and refractive index of the outermost surface layer 11 . That is, the color tone of the battery cell 10 can be controlled by the design of the outermost surface layer 11 . In addition, the closer the intensities of the reflected light Ra and the reflected light Rb are, the stronger the interference effect is and the clearer the tone is. For example, as shown in FIG. 3 , when the battery unit 10 having the surface layer 11 is packaged with the packaging material 103 , the intensity of the reflected light RA generated by the surface of the surface layer 11 is smaller than that generated by the surface of the battery unit 10 . The intensity of the reflected light RB weakens the interference effect.

Therefore, as shown in FIG. 3 , in the existing module structure, the outermost surface layer 11 of the encapsulated battery unit 10 is in close contact with the encapsulating material 103 . Therefore, the refractive index between the encapsulating material 103 and the outermost layer 11 is The difference becomes smaller, and the intensity of the reflected light RA becomes smaller. Therefore, the interference between the reflected light RA and the reflected light RB becomes weak. As a result, the reflected light RB of the battery cell 10 becomes the main component and appears in a color close to black.

On the other hand, as shown in FIG. 4 , in the module 100 according to the embodiment, a planar (thin layer) air layer 13 is provided between the sealing material 103 and the outermost surface layer 11 as a means for the sealing material to 103 is an unbonded area that is not in close contact with the surface layer 11 . In this way, the refractive index difference between the reflected light RAA from the surface of the outermost layer 11 of the battery cell 10 and the reflected light RBB from the light-receiving surface of the battery cell 10 becomes larger. Therefore, the interference effect between the reflected light RAA from the outermost surface layer 11 and the reflected light RBB from the light-receiving surface of the battery cell 10 becomes stronger, so that the desired hue of the light-receiving surface color of the battery cell 10 is not impaired, and the battery cell 10 are modular. That is, as shown in FIG. 4 , the module 10 covers the outermost layer 11 with the gas layer 13 so that the intensity of the reflected light RAA generated by the outermost layer 11 is close to that of the reflected light RBB generated by the light-receiving surface of the battery unit 10 . Therefore, , the tone also becomes clear.

Here, as a method of providing the planar gas layer 13 between the sealing material 103 and the outermost layer 11, as shown in FIG. 4, a transparent resin sheet 15 may be provided on the outermost layer 11 of the battery cell 10. and the packaging material 103. The sheet 15 is not particularly limited as long as it is in close contact with the sealing material 103 and not in close contact with the outermost surface layer 11 of the battery cell 10 . Examples of the sheet 15 include polyethylene terephthalate, polyvinyl fluoride, and fluororesin sheets. The sheet 15 may be arranged on each battery unit 10 between the battery unit 10 and the first sealing material 103a, or may be arranged on the entire surface corresponding to the protective materials 105A and 105B. In addition, the gas layer 13 is not particularly limited, and may be an air layer, a nitrogen gas layer, or the like.

The method of changing or adjusting the color of the light-receiving surface of the battery cell 10 is not particularly limited. For example, there is a method of changing the film thickness of the outermost layer 11 of the battery cell 10 . For example, a back contact solar cell (back contact battery cell) may be used as the battery cell 10 . In the back contact cell, p-type semiconductor layers and n-type semiconductor layers are alternately provided on the back side of a semiconductor substrate made of crystalline silicon or the like, and a passivation layer and an anti-reflection film are provided on the light-receiving surface side in order from the substrate side. By adjusting the film thickness of the antireflection film corresponding to the outermost surface layer 11, the color can be easily adjusted.

It should be noted that the semiconductor substrate is formed of a conductive single crystal silicon substrate. Generally, there are n-type and p-type single-crystal silicon substrates. The n-type single-crystal silicon substrate is doped with atoms that introduce electrons to silicon atoms (such as phosphorus (P)), and the p-type single-crystal silicon substrate is doped with There are atoms that donate holes to silicon atoms (such as boron (B)). The "one conductivity type" mentioned here refers to either n-type or p-type. That is, the semiconductor substrate is a single crystal silicon substrate having n-type or p-type conductivity.

In addition, as in this embodiment, when the air layer 13 is provided between the first sealing material 103a on the light-receiving surface side of the sealing material 103 and the battery unit 10, as will be described later, flying birds and the like are suppressed. The propagation of the shock wave when an object collides with the module 10. Therefore, it is possible to prevent battery cells from being broken due to shock waves. As a result, performance degradation of the module 100 is suppressed and the module 100 has high reliability.

In addition, as shown in FIG. 5 , the sheet 15 may be a sheet 15A in which at least the surface facing the gas layer 13 is roughened. In this way, by roughening the sheet 15A in a concave and convex shape, light incident into the module 100 is reflected by the roughened surface, thereby causing a re-incidence effect of the light incident on the battery unit 10 . Furthermore, the air layer 13 can be easily provided by roughening the inside of the sheet 15A.

The roughness degree of the sheet 15A may be set such that the arithmetic mean roughness Ra ₁ is 1 μm or more and 10 μm or less, for example. In the case of an uneven shape, it is preferable to have an embossed shape that satisfies a width of 0.5 mm or more and 1.5 mm or less, a length of 0.5 mm or more and 1.5 mm or less, and a depth of 0.01 mm or more and 0.1 mm or less, or an inclined surface. A triangular shape with an inclination angle set within a specified range.

[Modular]

As shown in FIG. 1 , in the module 100 according to the embodiment, a battery cell string 10A in which a plurality of battery cells 10 are connected by wiring 102 is sandwiched between a light-receiving surface protective material 105A and a back surface protective material 105B via a sealing material 103 . hold. The sheet 15 is provided on at least the light-receiving surface of each battery unit 10 with the planar gas layer 13 interposed therebetween. For example, the first encapsulating material 103a, the sheet 15, the battery cell string 10A, the second encapsulating material 103b, and the back surface protective material 105B are sequentially placed on the light-receiving surface protective material 105A to form a laminate, and the formed laminate is subjected to predetermined conditions. By heating and solidifying the sealing materials 103a and 103b, the battery cell string 10A can be sealed.

As the sealing material 103, a polyethylene resin composition containing an olefin elastomer as a main component, polypropylene, ethylene/α-olefin copolymer, ethylene/vinyl acetate copolymer (EVA), ethylene/vinyl acetate/ Transparent resins such as triallyl isocyanurate (EVAT), polyvinyl butyrate (PVB), silicon, polyurethane, acrylic, or epoxy. The first encapsulating material 103a on the light-receiving surface side and the second encapsulating material 103b on the back side may be made of the same material or different materials.

The light-receiving surface protection material 105A has light transmittance, and for example, glass or transparent plastic is used.

On the other hand, the back surface protective material 105B has any one of light transmittance, light absorptivity, and light reflectivity. As the light-reflective back surface protective material 105B, it is preferable to have a metallic color, white color, or the like. For example, a white resin film or a laminate in which a metal foil such as aluminum is sandwiched between resin films is suitable as the back surface protective material 105B.

In addition, as the light-absorbing back surface protective material 105B, for example, a member including a black resin layer and the like and having a black appearance can be suitably used. When the back surface contact battery unit 10 having, for example, a black light-receiving surface (battery cell surface) is modularized using such a light-absorbing back surface protective member 105B (for example, a black sheet), the back surface protective material 105B and the battery unit 10 The appearance colors are similar, so the gaps between the battery cell strings 10A are inconspicuous, and the module 100 with a high aesthetic appearance is obtained.

In addition, in the battery cell string 10A, the battery cells 10 adjacent to each other may adopt a tile roof structure (shingled structure), and a part of one battery unit 10A overlaps a part of the other battery unit 10B. However, this is not the case. Illustration. When such a shingled structure is adopted, there is no gap between the battery cells 10 in the battery cell string 10A. Therefore, for example, when a module 100 with a shingled structure is formed using battery cells 10 having black light-receiving surfaces, the battery cell surfaces on the light-receiving side of the module 100 can be uniformly black, etc., thereby improving the appearance. Furthermore, in such a module 100, if a black-based back protection member 105B is used, for example, the entire light-receiving side surface of the module 100 can be reliably unified into a black color, thereby further improving the appearance.

It should be noted that the example of the battery cell 10 having a black-based light-receiving surface has been described above. However, the battery cell 10 is not limited to the black-based system. For example, a battery cell 10 using a dark blue-based or dark green-based light-receiving surface (battery cell surface) In the case of the module 100 of the battery unit 10, the appearance color of the back protection member 105B and the color of the battery unit surface may be the same color. That is, if the color of the cell surface of the battery unit 10 and the appearance color of the back protection member 105B are of the same series, the appearance of the module 100 can be improved.

[Example]

Examples and comparative examples are shown below.

[Fabrication of back contact battery cells]

The back-contact battery unit was fabricated using a 6-inch n-type single crystal silicon substrate (semi-square type with a side length of 156 mm) with a texture of 160 μm on the two opposite main surfaces. As the metal electrode on the back surface, silver paste was screen-printed on the n-type semiconductor layer and the p-type semiconductor layer respectively, and then baked at a temperature of 150° C. for about 30 minutes.

On the light-receiving surface, a passivation layer and an anti-reflective film are formed in sequence. Silicon nitride (SiN) with a refractive index of 1.9 was produced with three film thicknesses of 45nm, 70nm, and 165nm using a chemical vapor deposition (CVD) method to obtain an anti-reflective film equivalent to the outermost surface layer 11. It should be noted that the film thickness of the anti-reflection film is a value on the inclined surface of the texture, which is obtained by measuring the SiN film formed on the glass substrate by ellipsometry and converting it into an inclined surface.

[Example]

Hereinafter, a method of manufacturing the module 100 according to the embodiment will be described with reference to FIG. 6 .

First, on the white glass as the light-receiving surface protection material 105A, the first sealing material 103a made of ethylene/vinyl acetate copolymer (EVA) and the PET sheet as the transparent resin sheet 15 are arranged in this order. Furthermore, a plurality of battery cells 10 and a second sealing material 103b made of EVA are placed, and a back plate having a black resin layer 105a on a PET film 105b as a base material is placed thereon as the back surface protective material 105B.

Next, thermocompression bonding was performed under atmospheric pressure for 5 minutes, and then the temperature was maintained at 150° C. for 60 minutes to cross-link the EVA to obtain the module 100 . At this time, each battery unit with three types of anti-reflection film thicknesses was modularized.

It should be noted that the PET sheet as the sheet 15 is placed evenly and entirely on the first packaging material 103a, but it is not limited to this. That is, the PET sheet may be disposed so as to cover at least the light-receiving surface (lower surface in FIG. 6 ) of each battery cell 10 . Furthermore, the gas layer 13 formed on the light-receiving surface of each battery unit 10 by using a PET sheet only needs to cover at least one-half of the area of the light-receiving surface of each battery unit 10 . The same applies to the following comparative examples.

[Comparative example]

A first sealing material made of EVA, a plurality of battery cells, and a second sealing material made of EVA are arranged on the white plate glass as the light-receiving surface protection material. A back sheet in which a black resin layer was provided on a PET film as a base material was disposed as a back surface protective material.

Next, after performing thermocompression bonding under atmospheric pressure for 5 minutes, the temperature was maintained at 150° C. for 60 minutes to cross-link the EVA to obtain a module. Here, the battery cells with anti-reflective films of three film thicknesses are also modularized.

As described above, the difference between the Example and the Comparative Example is that in the Example, the sheet 15 for forming the gas layer 13 is arranged between the first sealing material 103 a and the light-receiving surface of the battery unit 10 .

[Check the color tone of solar cells and battery cells in modules]

The light-receiving surface of each of the three types of battery cells 10 produced was observed, and the color tone of each was confirmed. In addition, the modules according to the examples and comparative examples were observed under sunlight. A was used to evaluate whether the color tone was close to the color tone of the anti-reflective film that passed through the battery cell 10, and B was used to evaluate whether the color bar was close to the color tone of the back sheet itself. The results are shown in [Table 1] below.

[Table 1]

Comparing the Example and the Comparative Example, it can be seen that in the Comparative Example, the color tones of the three types of battery cells 10 in the module are close to the color tone of the back plate, that is, the black color. In contrast, in the Example, the three types of battery cells 10 in the module can be produced. The module 100 has a color tone of each battery unit 10 close to that of the battery unit 10 . In the module structure of the comparative example, since the surface of the battery cell is in close contact with the packaging material, the refractive index difference between the packaging material and the outermost surface layer of the battery cell becomes small. As a result, the reflected light from the outermost surface layer becomes smaller, and therefore the interference light becomes weaker. The reflected light from the light-receiving surface of the battery cell becomes the main component, and appears in a color close to black.

On the other hand, in this embodiment, the planar gas layer 13 is provided between the sealing material 103 and the outermost surface layer 11 of the battery cell 10 . The planar gas layer 13 increases the reflected light RAA based on the difference in refractive index between the reflected light RAA generated by the outermost surface layer 11 and the reflected light RBB generated by the light receiving surface of the battery cell 10 . The reflected light having a different refractive index interferes with the reflected light RBB. As a result, the module 100 is realized that does not impair the color tone of the light-receiving surface of the battery cell 10 .

[Impact resistance of solar cell modules]

Next, the case where the impact resistance of the module 100 of the Example is improved compared with that of the Comparative Example will be described.

After fabricating the battery unit 10 with an antireflection film made of silicon nitride (SiN) with a film thickness of 70 nm, the modules of the above-described Examples and Comparative Examples were implemented, and an impact resistance test was performed respectively. Heavy objects weighing 1.5 kg, 2.6 kg, and 4.8 kg were dropped from a height of 80 cm, and photoluminescence (PL) was used to confirm whether cracks were observed in the battery cells 10 in each module. As the confirmation results, the case where no cracks were observed was evaluated by A, and the case where cracks were observed was evaluated by B, and the results are shown in [Table 2] below.

[Table 2]

Regarding the impact resistance test, when the Examples and Comparative Examples are compared, in the Comparative Example, cracks were observed in the battery unit 10 for heavy objects weighing 2.6 kg and 4.8 kg. On the other hand, in the Examples, no cracks were observed in the battery cell 10 regardless of the weight of the weight. This is considered to be because the planar gas layer 13 provided between the packaging material 103 and the battery cells 10 suppresses the propagation of shock waves when they collide with the module 100 and prevents the battery cells from rupturing due to the shock waves.

(Modification of the embodiment)

In the solar cell module 100 shown in FIG. 1 , a back contact cell (back contact cell) is used as the cell 10 . However, the solar cell module 100 is not limited to this. As shown in FIG. 7 , the double-sided electrode is It can also be applied to the case of type battery unit 10a.

As shown in FIG. 7 , in the module 100A according to this modification, the surface electrode (for example, a p-type electrode) of one battery cell 10 a and the back electrode (for example, a p-type electrode) of another adjacent battery cell 10 a are alternately connected. n-type electrode). In the battery cell string 10A configured in this manner, a transparent resin sheet 15 is provided between the outermost surface layer, which is the light-receiving surface of each battery cell 10a, and the first sealing material 103a.

When modules are installed on the wall of a building, since the modules lack changes in appearance, they do not blend in with the appearance of the wall (for example, the color of the wall), which may cause a deterioration in the aesthetic appearance of the building. In addition, when flying objects collide with the module, the battery cells in the module may sometimes break, which may also cause the performance of the battery cells to decrease.

However, as described above, according to the module 100 and the module 100A according to the above embodiments and examples, the gas layer 13 is provided between the sealing material 103 and the light-receiving surface of each battery unit 10 , 10 a , so that the battery unit 10 is not damaged. , 10a color tone can achieve excellent appearance.

In addition, cracks generated in the battery cells 10 and 10a of the modules 100 and 100A due to the impact of flying objects can be suppressed, thereby realizing the modules 100 and 100A having excellent reliability.

In addition, since the light-receiving surface of each battery unit 10 and 10a is covered with the gas layer 13, the resistance to potential induced degradation (PID) phenomenon can also be improved. The PID phenomenon occurs when glass is used as the protective materials 105A and 105B. For example, sodium (Na) ions or the like diffuse from the protective materials 105A and 105B into the packaging material 103 at a high voltage and invade into each battery cell 10 , 10a surface or internal resulting output drop. Therefore, the modules 100 and 100A suppress the PID phenomenon and exhibit high reliability.

-Symbol Description-

100, 100A solar cell module (module)

102 Wiring

103 Packaging materials

103a First packaging material

103b Second packaging material

105A Light-receiving surface protection material (protective component)

105B Back protection material (protective component)

105a black resin layer

105b PET film

10, 10a solar cell (battery unit)

10A solar cell (battery unit) string

11 The surface layer (anti-reflective film)

13 air layers

15 sheets (transparent resin/PET sheet).

Claims (5)

1. A solar cell module, which includes: a plurality of solar cell units, a plurality of the solar cell units are electrically connected; a packaging material, the packaging material encapsulates a plurality of the solar cell units; and two protective components, both Each of the protective members, together with a plurality of the solar cell units, clamps the packaging material from two opposite main surface sides of the solar cell unit, and is characterized in that: Each solar cell unit is provided with an air layer between at least one of the two main surfaces and the packaging material opposite to the main surface, On the main surface of the light-receiving side of each solar cell unit, an anti-reflective film and a transparent resin sheet located on the anti-reflective film are arranged in sequence. The gas layer is a combination of the anti-reflective film and the the interstitial layer between the sheets, The surface of the sheet facing the anti-reflection film is roughened. 2. The solar cell module according to claim 1, characterized in that: The gas layer is planar and is provided between the main surface of the light-receiving side of each solar cell unit and the packaging material. 3. The solar cell module according to claim 1 or 2, characterized in that: The gas layer covers at least one-half of the main surface of each solar cell unit. 4. The solar cell module according to claim 1 or 2, characterized in that: The gas layer is an air layer. 5. The solar cell module according to claim 1 or 2, characterized in that: Each of the solar cells is a back contact solar cell.