JPH0883920A - Manufacture of different coloring crystalline silicon solar cell - Google Patents

Abstract

PURPOSE: To provide a method for manufacturing a crystalline silicon solar cell in which its photoelectric conversion efficiency is not almost deteriorated even if it is used for a building material, etc., by differentiating apparent coloring of the cell except dark navy blue, etc., and to apply it to various utilities. CONSTITUTION: The thickness T of a reflection preventive film 4 formed to improve the photoelectric conversion efficiency via an oxide film 3 at the light receiving side diffused layer 2a of a crystalline silicon substrate l is increased or decreased in the past manufacturing step of a crystalline silicon solar cell to obtain a product which becomes apparent various different coloring. In this case, the baking temperature of the baking surface electrode 6 is raised or lowered in proportion to the increase or decrease in the thickness T at the layer 2a. Thus, the various coloring product in which the efficiency is not almost decreased can be manufactured even if any apparent coloring is conducted, and a wide utility can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION In the present invention, when a crystalline silicon solar cell element is manufactured, its apparent coloration is defined as a dark blue or purple color for the purpose of merely improving photoelectric conversion efficiency. Rather than storing it, when trying to expand the application by selecting a harmonious coloration from a design point of view depending on the application and installation location, as described above, a color different from navy blue or purple The present invention also relates to a method for manufacturing a crystalline silicon solar cell element in which the conversion efficiency is not lowered as much as possible even if

[0002]

2. Description of the Related Art A crystalline silicon solar cell element A is known as one of cells in currently commercialized solar cell modules, and has a structure as shown in FIG. In the figure, reference numeral 1 denotes a single crystal or polycrystalline silicon substrate (for example, a P substrate), on the light receiving surface side thereof, a light receiving surface side diffusion layer 2a (N ⁺ layer) and an oxide film 3 are sequentially formed.
(SiO ₂ ) and antireflection film 4 (TiOx) are laminated,
On the back surface side of the crystalline silicon substrate 1, a back surface diffusion layer 2b (P ⁺ layer) and a back surface electrode 5 are sequentially laminated.

As the back surface electrode 5, the back surface diffusion layer 2b is used.
Is formed by the Al electrode 5a that is in contact with and the back surface Ag electrode 5b that is stacked on the Al electrode 5a.
A surface electrode 6 (Ag electrode) is baked on the light receiving surface side diffusion layer 2a, and a surface side solder 6a is formed on the upper surface of the surface electrode 6 exposed from the antireflection film 4 and a back surface. Back surface side solder 5c is also welded to the lower surface of the Ag electrode 5b.

Here, as a crystalline silicon solar cell element currently commercialized, it is of course urgent to improve the photoelectric conversion efficiency of the above-mentioned solar cell module A. The antireflection film 4 is formed on the light receiving surface side. As the antireflection film 4, titanium oxide (TiOx) or silicon nitride (SiN) is used.
x) is generally used, whichever anti-reflection coating is used so that the apparent coloration on the light-receiving surface side is in the wavelength range of light from dark blue to purple. 4 is formed so as to control the thickness and the refractive index N (see FIG. 3). Therefore, all the solar cell elements of this type currently commercialized have an apparent dark blue or purple appearance. It is colored.

That is, the apparent coloration as described above is
The dark blue color means that the crystalline silicon solar cell has a high sensitivity to red and infrared light having a wavelength of 800 to 1000 nm, and therefore the light should not be reflected as much as possible. It is due to the attempt to improve the photoelectric conversion efficiency.

However, solar cell modules actually manufactured using such crystalline silicon solar cell elements are used in various environments such as parks, roadsides, and in the mountains. Since it will be used in houses and toys that are not practically used, in these wide fields,
In order to popularize the crystalline silicon solar cell element, a product having various different colors, which is not limited to the above-mentioned existing colors, is required.

[0007]

In the crystalline silicon solar cell element shown in FIG. 1, when TiOx (refractive index N = 2.25) is actually used for the antireflection film 4, The film thickness is selected to be about 600Å, and the apparent color is dark blue. By doing so, the output is maximized as described above. At this time, TiO
It is known that the relationship between the laminated thickness T of x: Å (film thickness) and the reflectance with respect to light of various wavelengths is as shown in FIGS. 3 (A) and 3 (B). If used, T
By changing the film thickness of iOx, it is possible to freely change the apparent coloration.
For example, when the film thickness T is 400 Å, (A) of FIG.
As can be understood from the wavelength range of light shown in FIG. 4 and the wavelength range of light having a high reflectance, the layer exhibits a reddish brown or yellow color, and the film thickness T is 1000Å.
When the film thickness T is increased up to 2,400, and when the film thickness T is increased up to 2,400 Å, it becomes green as can be seen from FIG.

In order to satisfy the requirements for coloration as described above, it is possible to make various different colors different from those of navy blue and the like, which have been used so far, to give an apparent color. As described above, the photoelectric conversion efficiency of the silicon solar cell manufacturing method decreases as the film thickness increases. That is, when the single crystal silicon solar cell element (10 cm square) as shown in FIG. 1 is manufactured by the manufacturing method so far, the surface electrode 6
An Ag electrode is used for the above, and when baking the light receiving surface side diffusion layer 2a, the baking temperature is set to 750 ° C. by a conventional method,
The thickness of the antireflection film 4 is 600Å, and the apparent color is dark blue.

Here, the above film thickness is set to 1200Å, 180
By forming as thick as 0Å and 2400Å, the apparent colors are gradually changed to light sky blue, red, and green, and by making the film thickness as thin as 300Å, it becomes brown, and further, this film. The color was changed to gray by approaching the thickness to zero. The characteristics of the various color-developed products thus obtained were tested, and the results shown in Table (1) were obtained. was gotten. As mentioned above, the thickness of the antireflection film is made larger than 600Å, and as the apparent color changes to various colors different from dark blue, the photoelectric conversion efficiency is up to about 10% or more. On the contrary, if the thickness of the antireflection film is made smaller than 600Å and the apparent color changes to brown etc., the photoelectric conversion efficiency will also decrease considerably. Becomes

According to the present invention, the above-mentioned conventional method is used to increase or decrease the thickness of the antireflection film to adjust the thickness of the antireflection film so that the apparent coloration becomes different from the conventional one. When a silicon solar cell element is manufactured, in claim 1, when the surface electrode is fired in the manufacturing process,
By increasing the firing temperature in proportion to the thickness of the laminated antireflection film, it is possible to obtain the product with the required different coloration without substantially deteriorating the photoelectric conversion efficiency. That is the purpose, and in the second aspect, the above-mentioned purpose can be more satisfied by specifying the relationship between the laminated thickness and the temperature rise.

Further, in the case of claim 3, claim 1
When a crystalline silicon solar cell element is manufactured by, a product having a different color that matches as much as possible with the wavelength region of the light that the back sheet of the solar cell module into which the crystalline silicon solar cell element is incorporated is obtained. By doing so, when a wall material or roofing material related to a house is manufactured using the solar cell module, the presence of the crystalline silicon solar cell element is not conspicuous and does not give a sense of discomfort as a building material, etc. The purpose is to be able to give sufficient satisfaction in terms of design.

[0012]

In order to achieve the above-mentioned object, the present invention provides a light receiving surface side diffusion layer, an oxide film, and an antireflection film which are sequentially laminated on the light receiving surface side of a crystalline silicon substrate. Same as above, on the back surface side of the crystalline silicon substrate, a back surface electrolytic layer of the same conductivity type as that of the crystalline silicon substrate and a back surface electrode are sequentially laminated, and in the light receiving surface side diffusion layer, the front surface electrode is fired and formed crystalline silicon. In the manufacturing process of the solar cell element, by increasing or decreasing the laminated thickness of the antireflection film,
The apparent color on the light-receiving surface side should be different from the wavelength range of light from dark blue to purple, and the firing temperature of the surface electrode should be increased as the layer thickness is increased. An attempt is made to provide a method for producing a characteristic differently colored crystalline silicon solar cell element.

In the second aspect, the laminated thickness of the antireflection film is increased by 30Å in the first aspect, while the firing temperature of the surface electrode is increased in a linear relationship of 1 ° C. The content is what you have done.

In the case of claim 3, as in the case of claim 1, by increasing or decreasing the laminated thickness of the antireflection film, the apparent color on the light-receiving surface side is changed to a wavelength of light from dark blue to purple. In addition to making the color different from that of the region, in the solar cell module in which the crystalline silicon solar cell element is incorporated, it is possible to match the wavelength range of light of the back sheet as much as possible. , Additional content.

[0015]

According to the manufacturing method of claim 1, not only is the laminated thickness of the antireflection film increased by a required dimension or formed thin so that the product has a desired different color, When firing the front surface electrode after the film forming process, the firing temperature is increased as the laminate thickness increases or decreases, instead of always firing at a constant temperature of about 750 ° C. as in the past products. It was also confirmed that, when lowered, the decrease in photoelectric conversion efficiency was improved, and that a product having characteristics not so different from those of conventional products could be manufactured.

According to the second aspect of the present invention, the most satisfactory photoelectric conversion efficiency can be obtained by increasing or decreasing the firing temperature with respect to the increase or decrease of the laminated thickness to 1 ° C. with respect to 30Å.

Further, according to claim 3, in the solar cell module obtained by incorporating the solar cell element, the back sheet of the solar cell element is not merely intended to obtain the solar cell element having a different color. Since different colors are specified so as to be the same color, if building materials etc. are manufactured by adding additional configuration to the solar cell module, it does not deteriorate the taste and design of the building until now. A material that can be used in the same manner as the building material of the present invention and that can supply electric output to various fields can be provided, and it can be popularized without resistance.

[0018]

EXAMPLES The manufacturing method according to the present invention will be described in detail below. When manufacturing a crystalline silicon solar cell element A as shown in FIG. After the texture processing, the light receiving surface side diffusion layer 2a is formed by phosphorus diffusion, and the oxide film passivation (Passi) is formed on the light receiving surface side diffusion layer 2a.
The oxide film 3 is formed by the vate process. Then normal pressure C
The TiOx film which is the antireflection film 4 is formed by the VD method.
Therefore, as is also known, tetra-
Using i-propyl titanate (TPT) and water, at a substrate temperature of 400 ° C, the stacking thickness is 0Å, 300Å, 600Å, 1
200 Å, 1800 Å and 2400 Å were produced respectively.

After that, the Al electrode 5a and the Ag electrode 5b are formed by the screen printing method as the back surface electric field layer 2b and the back surface electrode 5, and the Ag electrode which is the front surface electrode 6 is baked. Further, if necessary, the back surface side solder 5c and the front surface side solder 6a are solder-coated on the back surface electrode 5 and the front surface electrode 6, respectively. Here, the feature of the present invention is that, as described above, the lamination thickness of the antireflection film 4 is about 600 Å, and the apparent coloration is dark blue. Was set to 750 ° C., but when the laminated thickness is made thicker or thinner than 600 Å to change the color change, the firing temperature is increased with the increase of the laminated thickness, and the same as above. The firing temperature is lowered with the decrease in the temperature, and this can greatly improve the decrease in the photoelectric conversion efficiency as shown in Table (1) above, as understood from Table (2) below. all right.

That is, if the firing temperature is increased or decreased, the characteristic deterioration can be prevented even if the antireflection film 4 is thickened or thinned to change the coloration. At this time, by raising or lowering the combustion temperature by about 1 ° C. with respect to the increase / decrease in the laminated thickness of 30Å, it was possible to obtain satisfactory results such as the numerical values shown in Table (2) above.

Next, the manufacturing method according to claim 3 will be explained. The crystalline silicon solar cell element A is also obtained by the manufacturing method according to claim 1 or claim 2, and at this time, In manufacturing the solar cell module B as exemplified by FIG. 2 by incorporating a required plurality of crystalline silicon solar cell elements described above,
The wavelength range of light that the back sheet 7 of the solar cell module B has and the crystalline silicon solar cell element A
The layer thickness of the antireflection film is selected so as to match the apparent coloration of the above item as much as possible.

Here, FIG. 2 shows a roof material or a panel material manufactured by using the above-mentioned solar cell module B. The solar cell module B is a plurality of crystalline silicon solar cells as is known. The battery element A is connected in series, the output terminals 8a and 8b thereof are led out, these are embedded in a filling material 9 made of synthetic resin or the like, and a light transmitting plate 10 made of glass or the like is arranged on the light receiving surface side thereof. In addition, the back sheet 7 made of the above-mentioned Tedlar or the like is disposed on the back surface side.

In the solar cell module B as described above, a protective material 11 made of an appropriate material is surrounded on its peripheral side surface, and a space formed by the protective material 11 and the back sheet 7 is formed. Since one building material C is configured as a whole by closing the backing material 12 made of refractory ceramic or the like, at this time, a color desirable for the building material C is selected for the back sheet 7 described above.
In the present invention, the apparent color of the crystalline silicon solar cell element A is set to be as similar to the color of the back sheet 7 as possible so that the apparent color as a whole becomes one color. Therefore, it can be used as a green wall panel or a brown roof panel, for example.

[0024]

The present invention is carried out as described above. Therefore, according to claim 1, no matter what color is selected as the apparent coloration, good photoelectric conversion efficiency can be obtained. Since it is possible to provide various crystalline silicon solar cell elements, it is necessary to put various colors into practical use for this type of product that could only be put into practical use for specific colors such as dark blue as before. It can be manufactured with the obtained photoelectric conversion efficiency, and by this, it becomes possible to spread it to building materials, toys, and various other uses.

According to claim 2, the photoelectric conversion efficiency can be brought to the most satisfactory state. According to claim 3, when the apparent color is selected, the solar cell module Since the color tone of the back sheet is matched, the presence of the crystalline silicon solar cell is not a concern, and thus it can be used for a wider range of applications.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional front view showing an example of a crystalline silicon solar cell element manufactured by the present invention.

FIG. 2 is a vertical cross-sectional front view showing a building material produced by a solar cell module incorporating the differently colored crystalline silicon solar cell element produced according to the present invention.

FIG. 3 shows the reflectivity with respect to the wavelength of the light irradiated on the laminated thickness (T) of the antireflection film in the crystalline silicon solar cell element, in which (A) T is 400Å to 1000.
Up to Å, (B) is each chart from 1200 Å to 2400 Å.

FIG. 4 is an explanatory diagram (wavelength region from radio wave to light) (cited from Optoelectronics Material Manual, FIG. 1 on P.3).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crystalline silicon substrate 2a Light receiving surface side diffusion layer 2b Backside electrolytic layer 3 Oxide film 4 Antireflection film 5 Backside electrode 6 Surface electrode 7 Solar cell module backsheet T Lamination thickness of antireflection film

Claims (3)

[Claims] 1. A light-receiving surface side diffusion layer, an oxide film, and an antireflection film are sequentially laminated on the light-receiving surface side of the crystalline silicon substrate, and the same conductive type as the crystalline silicon substrate is sequentially formed on the back surface side of the crystalline silicon substrate. To increase or decrease the laminated thickness of the antireflection film in the manufacturing process of the crystalline silicon solar cell element in which the back surface electrolytic layer and the back surface electrode are laminated, and the light receiving surface side diffusion layer has the surface electrode baked and exposed. Thus, the apparent color on the light-receiving surface side is made different from the wavelength range of light from dark blue to violet, and the firing temperature of the surface electrode is increased as the above-mentioned lamination thickness is increased. A method of manufacturing a differently colored crystalline silicon solar cell element, comprising: 2. A light-receiving surface side diffusion layer, an oxide film, and an antireflection film are sequentially laminated on the light-receiving surface side of the crystalline silicon substrate, and the same conductive type as the crystalline silicon substrate is sequentially formed on the back surface side of the crystalline silicon substrate. To increase or decrease the laminated thickness of the antireflection film in the manufacturing process of the crystalline silicon solar cell element in which the back surface electrolytic layer and the back surface electrode are laminated, and the light receiving surface side diffusion layer has the surface electrode baked and exposed. This makes the apparent color on the light-receiving surface side different from the wavelength range of light up to dark blue and violet, and increases the above-mentioned lamination thickness by 30Å, while the firing temperature of the surface electrode is set to 1 A method for producing a differently colored crystalline silicon solar cell element, characterized in that the temperature is raised in a linear relationship with the temperature. 3. A light-receiving surface side diffusion layer, an oxide film, and an antireflection film are sequentially laminated on the light-receiving surface side of the crystalline silicon substrate, and the same conductive type as the crystalline silicon substrate is sequentially formed on the back surface side of the crystalline silicon substrate. To increase or decrease the laminated thickness of the antireflection film in the manufacturing process of the crystalline silicon solar cell element in which the back surface electrolytic layer and the back surface electrode are laminated, and the light receiving surface side diffusion layer has the surface electrode baked and exposed. The apparent color on the light-receiving surface side is different from the wavelength range of light up to dark blue and violet, and in the solar cell module in which the crystalline silicon solar cell element is incorporated, A differently colored crystalline silicon, characterized in that the firing temperature of the surface electrode is increased as the above-mentioned lamination thickness is increased while matching the light wavelength region of the sheet as much as possible. Method for manufacturing solar cell element.