JP2003086818A - Solar battery module and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new solar battery module and electronic equipment using the same capable of hardly generating the short-circuit of adjacent cells even when any foreign matter, especially, particle is mixed, and stabilizing an electromotive force and a current value to be extracted from the solar battery even when a disconnection is caused in a process for manufacturing the solar battery constituted of a thin width corpus striatum which is not perceptible by the human eyes on a transparent substrate. SOLUTION: This solar battery is provided with at least one thin width corpus striatum group constituted of a plurality of adjacent thin width corpus striatums whose base edge parts are connected to the respective solar battery electrode parts of solar batteries.

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 and an electronic device using the solar cell, and in particular, it can be installed on the viewing side of the display part of the electronic device so as not to impair the visibility of the display part. A novel solar cell module that improves the manufacturing yield of a solar cell module that forms a solar cell by a plurality of narrow filaments on a transparent substrate, and that has stable electromotive force and current value, and an electronic device using the same It is related to equipment.

[0002]

2. Description of the Related Art There are portable electronic devices such as calculators, watches, liquid crystal display devices and PDAs which use solar cells as primary batteries.
The solar cell is composed of an amorphous silicon, and an alloy-based or microcrystalline or crystalline silicon or a power generation layer of a compound semiconductor material, and the electronic device transfers energy photoelectrically converted by the solar cell to a secondary battery. It is configured to store electricity and drive electronic devices. The demand for electronic devices driven by these solar cells is increasing year by year. Hereinafter, a solar cell watch will be mainly described as an example of the electronic device.

In a solar cell clock, light is converted into electric energy by the solar cell to charge a secondary battery such as a nickel ion battery (not shown), and the electric energy is taken out from the secondary battery to be used in the timepiece. Is designed to drive. In this case, the electromotive voltage obtained from one solar cell is relatively small and is not sufficient to drive the timepiece, so a plurality of solar cells are connected in series or a booster circuit is used to obtain the required voltage. In many cases. Eg 4
In a solar cell module in which individual solar cells are connected in series to obtain a combined electromotive force, a solar cell module having a shape as shown in FIG. 10 is usually used.

In the arrangement of solar cells shown in FIG. 10, the electrode portions of four solar cells 6 are connected to each other by connecting electrodes 38.
Electrodes 7 that are connected to each other and provided at both ends thereof
The electromotive force is extracted from a and 7b.

Generally, the solar cell 6 is opaque and has a special color (dark purple when the power generation layer of the solar cell is formed of amorphous silicon). Since it is difficult to use it on the surface of the information display means 1 of the electronic device including it, for example, it is formed integrally with the dial or arranged on the lower side of the dial. Further, the solar cell 6 itself may be covered with a semitransparent member so that it cannot be recognized.

Specifically, as shown in FIG. 8, a solar cell module 3 having time characters and the like printed on the protective film surface of the solar cell is arranged at the position of the information display means 1 of the timepiece, and this is directly placed on the dial. In many cases, the solar cell module 3 is arranged below the light-transmittable information display means 1 such as a dial having a transparent portion or a translucent dial as shown in FIG. .

However, a timepiece having such a configuration is poor in versatility in terms of design and structure and is difficult to design, resulting in high cost, and is limited to a special purpose or not. It was the only thing that distributed only a certain amount of products.

As a method for solving the above technical drawbacks, a solar cell composed of a narrow linear body is formed on a transparent substrate 4 as shown in FIG. 11 and is perceived by human eyes. There is proposed an electronic device including a clock or a liquid crystal display device in which a solar cell configured so as not to be provided is provided above the information display means 1.

The solar cell module 3 shown in FIG.
Each of the cells has a solar cell electrode portion 37 and a plurality of narrow linear members 35 whose base ends are connected to the solar cell electrode portion 37, and is transparent. The plurality of narrow line-shaped linear bodies 35 of one cell and another cell formed on at least one main surface of the flexible substrate 4 are arranged in parallel with each other at a predetermined interval in a comb-tooth shape. ing. The four cells 31 to 34 are connected in series at the connection electrode 38, and the electromotive force is extracted from the extraction electrodes 7a and 7b.

When the width of the thin linear members 35 shown in FIG. 11 is L and the interval between the narrow linear members 35 is P, the visibility of the information display means 1 through the solar cell module 3 is high. From the above point, it is preferable that L is as thin as possible. However, if the width L is extremely thin and P is extremely wide, the power generation effect is impeded, so the width L is 8 μm to 200 μm.
μm, preferably 8 μm to 20 μm. The P
Can be arbitrarily set depending on the area of the solar cell module and the required power generation, but from the viewpoint of the visibility of the information display means 1, it is preferably 100 μm or more.

12A and 12B show an electronic device 10 having the solar cell module 3 shown in FIG. 11, the electronic device 10 is a timepiece, and the information display means 1 is a dial. Reference numeral 21 is a support of the information display means 1, and reference numeral 22 is a movement having drive motors for the hour and minute hands 8 and 9.

Since the solar cell module 3 is constructed so as not to impair transparency, it is arranged on the dial as shown in FIG. 12 (A) and the design designed on the dial is applied to the solar cell module 3. The user can see through the watermark. Further, as shown in FIG. 12 (B), the same effect can be obtained by disposing the solar cell module 3 under the windshield.

[0013]

By the way, the narrow strip pattern is usually formed by a photolithography / etching process. However, in the solar cell shown in FIG.
When forming a thin linear pattern with a width of about 100 μm in the photolithography / etching step, a short circuit or a wire breakage easily occurs due to the inclusion of foreign matter, especially particles. If the pattern of the solar cell is formed while the foreign matter is attached so as to straddle the adjacent narrow linear members 35, the adjacent cells are short-circuited. That is, since the adjacent narrow line-shaped body patterns are extended and connected to the adjacent cells, the adjacent cells are short-circuited and the desired electromotive force cannot be taken out.

When a short circuit occurs between cells and the voltage of the entire solar cell becomes equal to or lower than the charging voltage for the secondary battery described above, the generated power cannot be stored in the secondary battery. Further, even when the narrow linear body 35 is broken due to foreign matter, the amount of current that can be taken out is reduced, and the secondary battery cannot be sufficiently charged. The problem peculiar to a solar cell having such a fine pattern cannot be found until the solar cell module is completed and an electromotive force check is performed, so it is not possible to find a location where a short circuit or disconnection has occurred and repair the cell. The load was too high and the cell had to be discarded as a bad cell.

It is an object of the present invention to remedy the above-mentioned drawbacks of the prior art and in particular to manufacture a solar cell on a transparent substrate composed of narrow filaments which are imperceptible to the human eye. In the process, even if foreign matter, especially particles are mixed, it is difficult for adjacent cells to be short-circuited with each other, and even if there is a disconnection, the electromotive force and the current value taken out from the solar cell are stable, and a novel solar cell module and this The electronic device used is provided.

[0016]

In order to achieve the above-mentioned object, the present invention basically adopts the technical constitution described below.

That is, the first means for solving the above-mentioned problems in the present invention is to form a plurality of solar cells by a plurality of narrow line-shaped bodies so as to leave the light transmitting portion on the transparent substrate. In the solar cell module according to the present invention, each solar cell has at least one thin linear body composed of a plurality of adjacent narrow line-shaped strips whose base end is connected to the solar cell electrode section of each solar cell. It is to be configured so as to have a width linear body group. A second means is that the narrow-width filament group connects at least a part of a plurality of narrow-width filament bodies forming the narrow-width filament group in a portion other than the solar cell electrode portion. It is configured to have a connecting portion.

A third means is to construct the narrow-width linear body groups so as to be parallel to each other and at equal intervals, and a fourth means is to configure the narrow-width linear body groups. The narrow strips are formed so as to be parallel to each other and arranged at equal intervals. The fifth means is that the intervals between the narrow strips are the narrow strips. And a sixth means is such that at least a part of the plurality of solar cells is connected in series, and a seventh means is the plurality of solar cells. The solar cell electrode portions of the battery are arranged so as to surround the narrow strips at positions symmetrical to each other.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The structure of a specific example of an electronic device with a solar cell according to the present invention will be described in detail below with reference to FIGS.

FIG. 1 is a plan view showing a first embodiment of a specific configuration of the solar cell module 3 according to the present invention. Solar cell module 3 formed on transparent substrate 4
Is divided into four cells 31 to 34, and each cell has a solar cell electrode portion 37 and a plurality of narrow linear bodies 35. A plurality of narrow line-shaped members 35 constituting each cell are arranged in parallel and adjacent to each other to form a narrow-width line member group 35a, 35.
b is formed. The narrow linear group 35 forming each of the narrow linear groups 35a and 35b has the base end portion of the solar cell electrode unit 3
7 and the cells 31 to 34 are connected to each other in series by appropriate connection electrodes 38.

Then, a plurality of narrow line-shaped body groups 35a, 35
b are arranged so that they are fitted in a comb shape.

In the present invention, a plurality (three in FIG. 1) of adjacent narrow linear members are connected to the same solar cell electrode section 37 as one set, so that different solar cell electrode sections 3 are connected.
It is possible to extremely reduce the probability of short-circuiting between cells connected to 7. In addition, even if adjacent narrow strips are connected to each other due to the inclusion of foreign matter, particularly particles, in a part of the narrow strips, the same solar cell electrode portion 37 is used.
The electromotive force taken out does not decrease as long as the narrow line-shaped bodies are connected to each other.

The number of the plurality of narrow line-shaped body groups 35a and 35b arranged in parallel in one set is three in FIG. 1, but the cells are short-circuited. In order to make it difficult, it is desirable to have as many as possible.
In this case, the base ends of the plurality of narrow line-shaped members 35 may be connected once to the common connection line and the connection line may be connected to the solar cell electrode part 37, but there is a risk of disconnection in the connection line. Figure 1 if available
As described above, it is better to directly connect the base end portions of the narrow width linear members 35 to the solar cell electrode portions 37. In addition, in FIG. 1, each cell is one narrow line group 35a, 3
Although shown as having 5b, in the present invention, each cell may have a plurality of narrow linear bodies.

Further, it is preferable that the narrow-width linear bodies 35 or the narrow-width linear body groups 35a, 35b are arranged in parallel and at equal intervals as shown in the drawing. This is because if the human eye has an irregular pattern, it immediately recognizes it and feels strange. However, different narrow line group 35a, 3
In order to avoid a short circuit between the 5b, the narrow width linear body group 35
The interval between a and 35b may be larger than the interval between the narrow line-shaped members 35.

FIG. 2 is a plan view showing a second embodiment of the configuration of another specific example of the present invention. The difference from the first embodiment is that a plurality of narrow-width linear bodies forming the narrow-width linear body group 35b are connected to each other by connecting portions 35c and 35d, and a part of the narrow-width linear bodies is formed. This is to prevent the output of the solar cell from decreasing as much as possible even when the power is cut.

In FIG. 2, the connecting portions 35c and 35d are composed of a plurality of narrow strips (3 in FIG.
Even when the foreign matter, especially particles are mixed in a part of the narrow linear body to cause a disconnection in the narrow linear body, the solar cell electrode is connected through the connecting portion. Part 37
Since the connection to is maintained, the current value taken out does not decrease.

It should be noted that the connecting position may be any position, and may be a plurality of positions as shown in FIG. 2, but it is desirable to provide at least one position as far as possible from the solar cell electrode section.
In addition, for example, in the case of a timepiece, it may be necessary to consider providing it at a position where it does not interfere with the display of the information display means 1, such as providing it at a position that does not cover the dial.

The number of the narrow linear members 35 is arranged differently for each cell, and the thin linear members of each cell are designed to have the same area, that is, the power generation area. Striatum may be arranged. This is because the power generation area of each cell is different, and if they are connected in series, the extraction current value of the solar cell is limited to the current value of the cell having the smallest power generation area. Therefore, in order to perform efficient power generation, it is important to make the power generation area of each cell the same.

In the above description, the cell is divided into four, but in order to obtain a desired electromotive force in accordance with the specifications of the solar cell module, the cell 31 and the cell 32 are integrally formed and the cell 33 is formed. The cell 34 and the cell 34 may be integrally formed to be a two-part solar cell, or, of course, the cells 31 to 34 may be integrally formed.

(Example) Next, a specific example of a method for manufacturing the solar cell module 3 according to the present invention shown in the first and second embodiments will be described in detail. The solar cells of the first and second embodiments are different only in the narrow linear body pattern, and other configurations are the same. Therefore, in order to form the narrow linear filament body depending on the specification and the application, The mask used in lithography can be changed and each can be formed in the same manufacturing process.

In the present invention, a transparent substrate such as glass or plastic is used as the transparent substrate 4 for forming a solar cell.

As a procedure for forming a solar cell, as shown in FIG. 3A, first, a lower electrode 12 made of a transparent conductive film is formed on a transparent substrate 4, and a photolithography method (hereinafter Resist pattern 40 by photolithography
To form. This resist pattern is a different pattern in the first and second embodiments.

Here, the case where indium tin oxide (ITO) is used as the material of the lower electrode 12 will be described.

First, the ITO film is formed by a sputtering method. The sputtering conditions at this time were as follows: 100 sccm of argon (Ar) gas and ₂ sccm of oxygen (O ₂ ) gas were introduced into the sputtering apparatus, the pressure inside the apparatus was 0.67 Pa to 4 Pa, and 1 KW to 3
It is performed by plasma generated by applying high-frequency power of KW (13.56 MHz).

Next, as shown in FIG. 3B, the lower electrode 1 is formed by using the resist pattern 40 as a mask pattern.
Etch 2.

The etching of the ITO film is performed by dry etching. The dry etching of ITO is performed by using 100 sccm to 300 sccm of hydrogen bromide (HBr) gas and 0 sccm to 100 sccm in a dry etching apparatus.
Argon gas is introduced, and the total pressure is 1.33 Pa
A high frequency power (13.56 MHz) of 1 KW to 3 KW is applied to this at 13.3 Pa, and the generated plasma is used. Then, the resist pattern 40 is once peeled off.

Thereafter, as shown in FIG. 3C, the power generation layer 13 made of an amorphous silicon (hereinafter referred to as a-Si) film on the surfaces of the transparent substrate 4 and the lower electrode 12.
Then, ITO, which is the upper electrode 14, is formed. Upper electrode 14
May be a metal film such as titanium or aluminum, but is preferably a transparent conductive film in order to utilize reflected light from the dial for power generation.

Here, the a-Si film is formed by plasma CVD.
By law. At this time, in order to form a P-type a-Si film, silane (SiH ₄ ) gas 5 is placed in the plasma CVD apparatus.
Diborane (B ₂ H ₆ ) gas of 00 sccm and 0.1 sccm to 1 sccm was introduced, and the pressure inside the device was adjusted to 67 Pa to 2
High frequency power of 50 W to 300 W (13.
Gas is decomposed by using plasma generated by applying (56 MHz), the temperature is set to 250 ° C., and the transparent substrate 4 is placed on the electrode connected to the reference potential.

To form an I-type a-Si film, 500 sccm of silane gas was introduced into the plasma CVD apparatus,
The pressure inside the device is 67 Pa to 266 Pa, and 50 W to 3
Gas is decomposed using plasma generated by applying 00 W high frequency power (13.56 MHz), and the temperature is set to 250 ° C.
And the transparent substrate 4 on the electrode connected to the reference potential.
To leave.

To form an N-type a-Si film, silane gas of 500 sccm and 0.1 s is placed in a plasma CVD apparatus.
A phosphine (PH ₃ ) gas of ccm to 1 sccm is introduced, the pressure inside the device is set to 67 Pa to 266 Pa, and 50 W
~ 300 W of high frequency power (13.56 MHz) was applied to generate plasma and decompose the gas to a temperature of 25
The temperature is set to 0 ° C., and the transparent substrate 4 is placed on the electrode connected to the reference potential.

The upper electrode 14 made of ITO is formed by a sputtering method as in FIG. 2A, and a resist pattern 41 is further formed thereon by photolithography.

Next, as shown in FIG. 4, the upper electrode 14 and the power generation layer 13 are simultaneously etched using the resist pattern 41 as an etching mask, and the resist is peeled off to form a solar cell pattern having a desired shape. To do.

First, the etching of ITO is performed by etching the lower electrode 1.
In the same manner as the pattern formation of No. 2, the dry etching apparatus is used, and a
-Etching the Si film.

The etching of the power generation layer 13 made of an a-Si film is performed at 100 sccm to 30 in a dry etching apparatus.
0 sccm of sulfur hexafluoride (SF ₆ ) gas and 0 sccm
Chlorine (Cl ₂ ) gas of up to 100 sccm was introduced to adjust the total pressure to 6.7 Pa to 27 Pa, and 100 W
It is performed by plasma generated by applying high frequency power (13.56 MHz) of 1000 W.

The etching of ITO and the etching of a-Si are performed by first exposing the lower electrode 12 and connecting the extraction electrode portions 7a and 7b, and the connection electrode 38 in the case of connecting cells in series. A gap for exposing the surface of the transparent substrate 4 located between the second narrow strips for the purpose of exposing the electrodes so that the information display part 1 such as a dial can be visually recognized. Is intended to form.

In this way, the specifications of the solar cell module 3,
Also, depending on the application, the photolithographic mask may be replaced to form a narrow linear body, whereby the solar cell module 3 having the pattern shown in FIG. 1 or 2 can be formed.

Subsequently, as shown in FIG. 5A, a protective film 45 is provided on the upper surface of the formed solar cell with a transparent resin or the like, or as shown in FIG. Board 4
A solar cell module is completed by providing an antireflection film 46 having a lower refractive index than that.

Next, in the case where the solar cell is divided into an arbitrary number of cells and the cells are connected in series, FIG.
The manufacturing process of the connection electrode 38 in FIG. Although the connecting electrode 38 has a different sectional structure from other solar cell portions, it can be formed at the same time as the narrow-width filament group described with reference to FIGS. 6 and 7 are views showing an example of a method of forming the connection electrode 38 for connecting adjacent cells in series.

First, according to the procedure of FIGS. 6 (A) and 6 (B),
A desired lower electrode pattern is formed on the transparent substrate 4.

Next, as shown in FIG. 6C, the power generation layer 13 made of an a-Si film and the transparent conductive film 14 as the upper electrode.
(ITO) is continuously formed, and a resist pattern 41 having a desired shape is formed thereon.

Further, as shown in FIG. 7D, the transparent conductive film 14 as the upper electrode and the power generation layer 13 are etched using the resist pattern 41 as an etching mask, and the resist pattern 41 is peeled off.

After that, the lower electrode 12 of one element and the upper electrode 14 of the other element are connected by the conductive paste 80, and the entire adjacent element is covered with the protective film 81, as shown in FIG.
Get the structure of. The parts other than the connection electrodes have the structure shown in FIG.

The power generation layer 13 of the solar cell 6 in FIGS. 3C to 7E of the present invention may be single crystal silicon or an amorphous silicon film. However, any other material having a photovoltaic force can be used.

[0054]

EFFECTS OF THE INVENTION According to the present invention, foreign matter, especially particles, are mixed in the formation of a solar cell module composed of a thin linear body which cannot be perceived by human eyes on a transparent substrate. Even so, it is possible to prevent a short circuit between cells and a structure that is not easily affected by disconnection, so that it is possible to prevent the electromotive force and the current value that are taken out from decreasing, and improve the manufacturing yield of the solar cell module. You can

Needless to say, the solar cell module of the present invention is a technology applicable not only to watches but also to solar cells of portable electronic equipment such as calculators, liquid crystal display devices and PDAs.

[Brief description of drawings]

FIG. 1 is a plan view showing a solar cell module according to a first embodiment of the present invention.

FIG. 2 is a plan view showing a solar cell module according to a second embodiment of the present invention.

FIG. 3 is a process cross-sectional view showing a manufacturing process of a solar cell module according to the present invention.

FIG. 4 is a process sectional view showing a manufacturing process of the solar cell module according to the present invention.

FIG. 5 is a structural cross-sectional view showing an example of a solar cell module obtained by the present invention.

FIG. 6 is a process sectional view of an electrode connecting portion of the solar cell module of the present invention.

FIG. 7 is a process sectional view of an electrode connecting portion of the solar cell module of the present invention.

FIG. 8 is a sectional view showing a configuration of a conventional timepiece with a solar cell.

FIG. 9 is a cross-sectional view showing another configuration of a conventional timepiece with a solar cell.

FIG. 10 is a plan view showing a conventional solar cell module.

FIG. 11 is a plan view showing an example of an electronic device in which a solar cell module is provided above the information display means.

FIG. 12 is a plan view showing another example of an electronic device in which a solar cell module is provided above the information display means.

[Explanation of symbols]

4 Transparent substrate 7a, 7b Extraction electrode 31-34 cells 35 narrow line 35a, 35b Narrow line filament group 35c, 35d connection part 37 Solar cell electrode part 38 Connection electrode

Claims (9)

[Claims] 1. A solar cell module comprising a transparent substrate and a plurality of solar cells formed of a plurality of narrow linear members so as to leave the light transmitting portion thereof, wherein each solar cell has a base end. Part is connected to the solar cell electrode part of each solar cell,
A solar cell module having at least one narrow-width filament group composed of a plurality of adjacent narrow-width filaments. 2. The narrow-width filament group is a connection for connecting at least a part of a plurality of narrow-width filament bodies forming the narrow-width filament group in a portion other than the solar cell electrode portion. The solar cell module according to claim 1, wherein the solar cell module has a portion. 3. The narrow-width filament group is provided parallel to each other and at equal intervals.
The solar cell module described in 1. 4. The narrow-width linear members forming the narrow-width linear member group are provided in parallel to each other and at equal intervals, according to any one of claims 1 to 3. Solar cell module. 5. The spacing between the narrow-width filament bodies is larger than the spacing between the narrow-width filament bodies.
The solar cell module described in 1. 6. The solar cell module according to claim 1, wherein at least a part of the plurality of solar cells is connected in series. 7. The solar cell electrode portions of the plurality of solar cells are provided at positions symmetrical to each other so as to surround each narrow linear body. 6. The solar cell module according to any one of 6. 8. The thin line member group of each of the plurality of solar cells is provided so as to form a comb tooth shape with the narrow wire member group of another solar cell. 1 to claim 7
The solar cell module according to any one of 1. 9. An electronic device having an information display means, characterized in that the solar cell module according to any one of claims 1 to 7 is arranged on the viewing side of the information display means. Electronics.