JP2738569B2 - Method for manufacturing photovoltaic device - Google Patents

Description

The present invention relates to a method of manufacturing a photovoltaic device in which a plurality of photovoltaic elements are connected in series.

(Prior art)

Usually, this type of photovoltaic device is configured as shown in FIGS. 3 (a) and 3 (b). FIG. 3 (a) is a cross-sectional structural view of a conventional photovoltaic device, and FIG. 3 (b) is a coaxial plan view, in which a transparent electrode 2, a pin junction is formed on a transparent insulating substrate 1. Photovoltaic element formed by laminating an amorphous semiconductor layer 5 and a nip junction type amorphous semiconductor layer 5 and a back electrode 6 in this order.
The back electrode 6 of one of the adjacent photovoltaic elements A among A, B... Is connected to the strip-shaped conductor 3 formed on the transparent electrode 2 of the other photovoltaic element B. The body 3 itself is kept parallel to the transparent electrode 2 and the amorphous semiconductor layer 5 of the other photovoltaic element B by the same strip-shaped insulator 4 and the photovoltaic element A , B,... Are connected to each other in series.

By the way, such a photovoltaic device is conventionally manufactured as shown in FIGS. 4 (a) and 4 (b).

FIGS. 4 (a) and 4 (b) are schematic diagrams showing a manufacturing process of the conventional method. First, as shown in FIG. 4 (a), after a transparent electrode 2 is formed on a transparent insulating substrate 1, This transparent electrode 2
Is cut into each of the regions constituting the photovoltaic elements A, B,... Also, near the one side edge of each of the transparent electrodes divided by the cutting, the strip-shaped conductive material is located along the cutting groove along the cutting groove. A body 3 is also formed in parallel with a strip-shaped insulator 4 which is located near the center of the transparent electrode at a required distance from the body 3.

Next, as shown in FIG. 4 (b), the amorphous semiconductor layer 5 over the transparent electrode 2, the cutting groove and the conductor 3, and the insulator 4
The back electrode 6 is laminated in this order, and a laser beam having a required line width is projected on the conductor 3 intermittently and on the insulator 4 continuously as shown by broken lines. .
As a result, on the conductor 3, the amorphous semiconductor layer 5 and the back electrode 6 are perforated in spots at the portions where the laser beam is projected, and the amorphous semiconductor layer 5 evaporates and The electrode 6 solidifies in a state in which the peripheral portion of the hole hangs down on the trace of the amorphous semiconductor layer 5 which has been evaporated and is in electrical contact with the conductor 3.

On the other hand, on the insulator 4, a laser beam is continuously projected, the amorphous semiconductor layer 5 and the back electrode 6 are both broken, and both the amorphous semiconductor layer 5 and the back electrode 6 evaporate. The back surface electrode 6 is solidified in a state where its broken edge hangs down on the trace of the evaporated amorphous semiconductor layer 5 and is in contact with the insulator 4.

As a result, as shown in FIGS. 3A and 3B, the amorphous semiconductor layer 5 and the back electrode 6 are cut on the insulator 4 for each of the photovoltaic elements A, B,. The back electrode 6 of one photovoltaic element is connected to the transparent electrode 2 of the other photovoltaic element through the conductor 3 so that adjacent photovoltaic elements are connected to each other in series.

By the way, in the conventional manufacturing method as described above, it is necessary to project a laser beam intermittently on the conductor 3 and continuously on the insulator 4, respectively. As a photovoltaic device, for example, between the transparent electrodes 2 and 2, under the conductor 3 and the insulator 4, and the portion sandwiched between them are ineffective portions that do not actually function as a solar cell or the like. The width of the body 3 and insulator 4 is
The laser beam spot diameter on the conductor 3 is 30 to 100 μm in order to surely maintain the contact between the conductor 3 and the conductor 3, and the amorphous semiconductor layer 5 of the adjacent photovoltaic element on the insulator 4 and the back electrode The line width of the laser beam on the insulator 4 is set to about 150 μm in order to reliably maintain the insulation of the conductor 6, and the conductor 3 and the insulator 4 are formed with a width of about 100 to 200 μm therebetween. Therefore, the entire invalid part is 500 to 700 μm
And the width of the invalid portion is large.

FIGS. 5 (a) and 5 (b) are other prior arts developed to solve the above-mentioned problems. FIG. 5 (a) is a sectional view, and FIG. 5 (b) is a plan view. It is. 6 (a) and 6 (b) show the manufacturing process.

In the figures, parts corresponding to FIGS. 3 (a) and (b) and FIGS. 4 (a) and (b) are given the same numbers.

In this conventional technique, a conductor 3 and an insulator 4 are formed in parallel with each other in contact with each other, and then the light-transmitting insulating substrate 1 and the conductor are exposed on the transparent electrode 2 at a cut portion between the transparent electrodes 2 and 2. 3, pin junction type or n over insulator 4
-An ip junction type amorphous semiconductor layer 5 and a back electrode 6 made of Al, Ti, Ag are laminated in this order to a required thickness.

Next, as shown by a broken line in FIG. 6 (b), a laser beam having a line width of 100 to 150 μm is projected so as to extend over both the conductor 3 and the insulator 4, and the amorphous semiconductor layer 5 and the back surface are formed thereon. Electrode 6
Is vaporized and divided, and the edge of the divided rear surface electrode 6 is dripped in a molten state to be solidified in contact with the surface of the conductor 3 and the surface of the insulator 4, respectively.

Thereby, the amorphous semiconductor layer 5 and the back electrode 6 in the adjacent photovoltaic element are separated from each other on the conductor 3 and the insulator 4, respectively, and the back electrode 6 of one photovoltaic element is connected to the other. Transparent electrode 2 via conductor 3 in the photovoltaic device of FIG.
Are electrically connected to each other to form a photovoltaic device in which the photovoltaic elements A, B,... Are connected in series.

In this prior art, a conductor and an insulator are formed adjacent to each other, and an amorphous semiconductor layer 5 and a back electrode 6 are formed on the conductor and an insulator, and this is formed on the conductor 3 and the insulator 4. At the same time, the edge of the back electrode 6 on the conductor 3 can be brought into electrical contact with the conductor 3.
Processing with a laser beam only needs to be performed once, which simplifies the processing. Further, since the conductor 3 and the insulator 4 are formed in contact with each other, an ineffective region between them can be removed, and the ineffective area can be reduced. Narrowing can also be achieved.

[Problems to be solved by the invention]

However, in this conventional technique, the series connection of the photovoltaic elements A, B,... Is performed only at one end of the back electrode 6 hanging on the conductor 3, and
The conventional method shown in the figure has the disadvantage that the contact area is small and the contact resistance is increased as compared with the case where welding is performed on the entire periphery of the spot portion. Welding has problems such as a weak connection portion and a high risk of disconnection.

The present invention has been made in view of such circumstances, and an object of the present invention is to simultaneously perform division and serial connection of a photovoltaic element by one processing using a laser beam, and to reduce low contact at a series connection portion. An object of the present invention is to provide a method for manufacturing a photovoltaic device that can obtain resistance and high connection strength.

[Means for solving the problem]

In the photovoltaic device according to the present invention, the surface of the transparent electrode separated for each region where each photovoltaic element is formed on the light-transmitting insulating substrate is electrically conductive in a strip shape in a state of being in contact with each other along the vicinity of the cut portion. After forming a body and an insulator, an amorphous semiconductor layer and a back electrode are formed in this order over the conductor, the insulator, and each of the cut transparent electrodes, and the amorphous layer is formed on the conductor and the insulator. The semiconductor layer and the back electrode are melt-cut using an energy beam formed into an asymmetric shape with respect to the boundary between the conductor and the insulator, and another photovoltaic element adjacent to the conductor is formed. And electrically contacting the back electrode.

[Action]

According to the present invention, this allows the adjacent photovoltaic elements to be brought into contact over a wide area by one operation of the energy beam.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to the drawings showing the embodiments. FIGS. 1 (a) and 1 (b) are schematic views showing a main part of a photovoltaic device manufactured by the method of the present invention, in which 1 shows a common translucent insulating substrate using glass or the like. I have. Each of the photovoltaic elements A,
B ... are formed. Each of the photovoltaic elements A, B,... Forms a transparent electrode 2 using SnO ₂ , ITO / SnO ₂ or the like on the common translucent insulating substrate 1 described above, and partially forms Al, After a conductor 3 using Ag or the like and an insulator 4 using glass or the like are formed adjacent to each other in a state of being in contact with each other, a pin junction type using amorphous silicon or the like on their surfaces, or ni is used. A p-junction type amorphous semiconductor layer 5 and a back electrode 6 using Al or the like are laminated in this order, and the amorphous semiconductor layer 5 and the back electrode 6 are respectively formed by photovoltaic elements by projecting a laser beam. A, B, etc., are cut off each other and are electrically isolated from each other by the insulator 4.
The back electrode 6 of one of the adjacent photovoltaic elements A, B... Contacts the transparent electrode 2 via the conductor 3 on the other photovoltaic element B, and Power elements A, B, ...
Are connected in series with each other.

The connection between the back electrode 6 and the conductor 3 is made at substantially equal intervals over the entire region above the conductor 3 in the peripheral region of the laser beam projection unit.

Next, a method for manufacturing such a photovoltaic device will be described with reference to FIGS. 2 (a), 2 (b) and 2 (c).

First, as shown in FIG. 2 (a), SnO ₂ or ITO / SnO ₂ is formed on a common light-transmitting insulating substrate 1 formed of glass or the like.
After the transparent electrode 2 made of such material is laminated on the entire surface, the transparent electrode 2 is formed by laser scribing on each photovoltaic element A,
The conductor 3 and the insulator 4 are cut and separated for each region where B is formed, and the separated transparent electrodes 2, 2 are in contact with the conductor 3 and the insulator 4 along the cut groove so as to extend over the entire length of one side edge. Let them be formed in parallel.

For example, the conductor 3 and the insulator 4 are formed by applying a conductor paste mainly composed of Ag or an insulator paste mainly composed of glass on the transparent electrode 2 in a strip shape by a conventionally known pen drawing method or the like. Later, it is formed by firing.

Then, on the transparent electrode 2 and on the transparent insulating substrate 1 and the conductors 3 and 4 exposed at the cut portions between the transparent electrodes 2 and 2, a pin junction type or an nip junction type is applied. A junction type amorphous semiconductor layer 5 and a back electrode 6 made of Al, Ti, Ag are laminated in this order to a required thickness.

Next, as shown in FIG. 2B, an iris 8 having a predetermined opening pattern and a lens 7 for forming an image of the opening pattern on the back electrode 6 are arranged in the optical path of the laser beam LB. 3. The laser beam LB is projected in a pulse shape with a width extending over both of the insulators 4. The opening pattern of the iris 8, that is, the laser beam projection pattern 9 is a pattern asymmetric with respect to the boundary between the conductor 3 and the insulator 4 as shown by hatching in FIG. a, a circular portion b, and a narrow slit portion c connecting the two portions a and b. The laser beam passing through the rectangular portion a is applied to the back electrode 6 on the insulator 4 and to the circular portion b. The laser beam that has passed through is projected onto the back electrode 6 on the conductor 3, and the slit-shaped portion c is formed of the conductor 3 and the insulator 4.
Are projected onto the back electrode 6 extending over both.

On the insulator 4, the laser beam passing through the rectangular portion a partially overlaps in the longitudinal direction of the insulator 4, and the laser beam passing through the circular portion b on the conductor 3 is separated from the laser beam by an appropriate length. The relative movement amount between the laser beam optical system and the photovoltaic device is appropriately set so that the light is projected in the state where the laser beam is projected. As a result, the laser beam LB is projected in a spot shape on the conductor 3, and the amorphous semiconductor layer 5 and the back surface electrode 6 are perforated at predetermined intervals in a portion where the laser beam is projected. The back electrode 6 is evaporated and the peripheral portion of the hole hangs down on the trace of the evaporated amorphous semiconductor layer 5 and solidifies while being in electrical contact with the conductor 3.

In addition, the amorphous semiconductor layer 5 and the back electrode 6 on the insulator 4 are both evaporated and separated, and the edge of the separated back electrode 6 is melted on the trace of the evaporated amorphous semiconductor layer 5. And solidify in a state of being in contact with the surface of the insulator 4.

As a result, the amorphous semiconductor layer 5 and the back electrode 6 in the adjacent photovoltaic elements A and B are both separated from each other on the conductor 3 and the insulator 4 and the back surface of one of the photovoltaic elements A The electrode 6 is electrically connected to the transparent electrode 2 via the conductor 3 of the other photovoltaic element B, and each of the photovoltaic elements A,
B ... are connected in series to form a photovoltaic device.

In the above embodiment, the laser beam projection pattern 9
Has been described as a series of a rectangular part a, a circular part b, and a slit part c. However, the present invention is not limited to this, and a spot on the conductor 3 and an insulator 4
Above, a pattern that can be independently blown in a rectangular shape may be used.

〔effect〕

As described above, in the method of the present invention, a conductor and an insulator are formed adjacent to each other, and an amorphous semiconductor layer and a back electrode are formed on the conductor and the insulator, and these are formed on the boundary between the conductor and the insulator. Using an energy beam asymmetrically shaped with respect to the line, the conductor was cut simultaneously on the conductor and insulator, and the edge of the back electrode on the conductor was brought into electrical contact with the conductor in a spot shape In this state, the processing with the energy beam can be performed only once, and the processing is simplified, and the connection area between the back electrode and the conductor on the conductor is large, and high connection strength can be obtained. As a result, the present invention has excellent effects such as high reliability with low contact resistance.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 (a) is a sectional structural view of a photovoltaic device manufactured by the method of the present invention, FIG. 1 (b) is a plan view thereof, and FIG.
FIGS. 3A, 3B and 3C are schematic sectional views showing main steps of the method of the present invention, and FIG. 3A is a sectional structural view of a photovoltaic device manufactured by a conventional method. 3 (b) is a plan view of the same, FIGS. 4 (a) and 4 (b) are schematic sectional views showing main steps of the conventional method, and FIG. 5 (a) is a light beam manufactured by another conventional method. Sectional view of electromotive force device, FIG. 5 (b)
6 is a plan view of the same, and FIGS. 6A and 6B are schematic sectional views showing main steps of another manufacturing method. DESCRIPTION OF SYMBOLS 1 ... Translucent insulating substrate, 2 ... Transparent electrode, 3 ... Conductor, 4 ... Insulator, 5 ... Amorphous semiconductor layer, 6 ... Back electrode, 7 ... Lens, 8 ... Iris, 9: Laser beam projection pattern

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Inoue 2--18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Yasuo Kishi 2-18-18 Keihanhondori, Moriguchi-shi, Osaka (56) References JP-A-62-88371 (JP, A) JP-A-63-102278 (JP, A) JP-A-63-156371 (JP, A) JP-A-63-280465 (JP JP, A)

Claims (1)

(57) [Claims] 1. A conductor and an insulator which are formed in a strip shape on a surface of a transparent electrode which is separated for each region where each photovoltaic element is formed on a light-transmitting insulating substrate and which are in contact with each other along the vicinity of a cut portion. Is formed, an amorphous semiconductor layer and a back electrode are laminated in this order over the conductor, the insulator, and each of the cut transparent electrodes, and the amorphous semiconductor layer and the backside electrode are formed on the conductor and the insulator. The back electrode is melt-cut using an energy beam formed into an asymmetric shape with respect to the boundary between the conductor and the insulator, and the conductor is contacted with the back electrode of another photovoltaic element in contact with the conductor. A method for manufacturing a photovoltaic device, comprising a step of making electrical contact.