JPH0397273A - Manufacture of photovoltaic device - Google Patents

Abstract

PURPOSE:To simplify the processing by a method wherein a conductor and an insulator are formed adjacent each other, an amorphous semiconductor layer and a rear electrode are laminated on the conductor and the insulator and these are cut in a simultaneous manner using an energy beam shaped asymmetrically with respect to the border line between the conductor and the insulator. CONSTITUTION:A transparent electrode 2 is laminatedly formed on the whole surface of a light-transmitting insulating substrate 1 and thereafter, with the electrode 2 cut and separated into two by laser scribing, a conductor 3 and an insulator 4 are formed in parallel with each other on the separated transparent electrodes 2 and 2 in a state that they are in contact with each other. Then, a lens 7 is arranged in the optical path of a laser beam LB and the laser beam LB is projected in a pulse status with width to cover both of the conductor 3 and the insulator 4. An open pattern of an iris 8, that is, a laser beam projection pattern 9 is an asymmetric pattern with respect to the border line between the conductor 3 and the insulator 4, for example. An amorphous semiconductor layer 5 and a rear electrode 6, which are located on the insulator 4, are both made to transpire and divided and the at the same time, the edge part of the electrode 6 is made to solidify at the trace of the transpired layer 5 in a state that is contacts with the surface of the insulator 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] 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 constructed as shown in FIGS. Figure 3 (a) is a cross-sectional structural diagram of a conventional photovoltaic device, and Figure 3 (opening) is a coaxial plan view.
A transparent electrode 2, a p-1-n junction type or n-i-p junction type amorphous semiconductor layer 5, and a back electrode 6 are laminated in this order on a transparent insulating substrate 1. A strip-shaped conductor in which the back electrode 6 of one adjacent photovoltaic element A is formed on the transparent electrode 2 of the other photovoltaic element B among the photovoltaic elements A, B... 3, and this conductor 3 itself is connected to the transparent electrode 2 of the other photovoltaic element B and the amorphous semiconductor N5 by the same strip-shaped insulator 4 formed parallel to this conductor 3 itself.
A method has been adopted in which the photovoltaic elements A, B, .

By the way, the manufacturing of such a photovoltaic device has conventionally been carried out as shown in Fig. 4 (
This is done as shown in (a) and (b).

FIGS. 4(a) and 4(b) are schematic diagrams showing the manufacturing process of the conventional method. First, as shown in FIG. 4(a), a transparent insulating base F
After laminating the transparent electrode 2 on the il, this transparent electrode 2
were cut into regions constituting each photovoltaic element A, B, etc., and near one side edge of each transparent electrode divided by cutting, a strip was placed along the cutting groove and located on the cutting groove side. A conductor 3 is formed in parallel with the conductor 3, and a strip-shaped insulator 4 is formed in parallel with the conductor 3 at a required distance from the conductor 3 and positioned closer to the center of the transparent electrode.

Next, as shown in FIG. 4(B), an amorphous semiconductor layer 5 and a back electrode 6 are laminated in this order over the transparent electrode 2, the cutting groove, the conductor 3, and the insulator 4. A laser beam with a required line width is projected onto the insulator 4 intermittently, and continuously onto the insulator 4 as shown by broken lines. As a result, N. Tft. On the body 3, the amorphous semiconductor layer 5 and the back electrode 6 are perforated in spots in the areas where the laser beam is projected, the amorphous semiconductor layer 5 is evaporated, and the back electrode 6 is perforated. The conductor 3 hangs down from the amorphous semiconductor layer 5 where the periphery of the hole was evaporated.
Solidifies when in electrical contact with.

On the other hand, the laser beam is continuously projected onto the insulator 4, and both the amorphous semiconductor layer 5 and the back electrode 6 are broken, and the amorphous semiconductor layer 5 and the back electrode 6 are evaporated. The back electrode 6 is solidified with its broken edge hanging down from the evaporated amorphous semiconductor layer 5 and in contact with the insulator 4.

As a result, as shown in FIG.
... is cut on the insulator 4, and the back electrode 6 of one of the associated photovoltaic elements is connected to the transparent electrode 2 of the other photovoltaic element through the conductor 3, so that the adjacent light The electromotive force elements are connected in series.

However, in the conventional manufacturing method as described above, it is necessary to project the laser beam intermittently onto the conductor 3 and continuously onto the insulator 4, which makes processing work difficult. This is troublesome, and in a photovoltaic device, for example, between the transparent electrodes 2, 2, under the conductor 3, insulator 4, and the part sandwiched between these is an ineffective part that does not actually function as a solar cell, etc. The width dimensions of the body 3 and the insulator 4 are such that the diameter of the laser beam spot on the conductor 3 is 30 to 100 μm to ensure that the back electrode 6 and the conductor 3 are maintained in contact with each other.
In addition, in order to maintain insulation between the amorphous semiconductor layer 5 and the back electrode 6 of adjacent photovoltaic elements on the insulator 4, the insulator 4
The line width of the laser beam with respect to the top is set to about 150 μm, and the conductor 3 and insulator 4 have a distance of 100 to 2 μm between them.
Since they are formed with a width of about 0.00 μm apart, the total ineffective portion is about 500 to 700 μm, and there is also a problem that the width of the ineffective portion is large.

Figures 5(a) and 5(opening) show other conventional technology developed to solve the above-mentioned problems. Figure 5(a) is a cross-sectional view, and Figure 5(opening) is a plan view. It is. Also, Figure 6 (a)
．． (mouth) indicates the manufacturing process.

The numbers in the figures refer to Figures 3 (a), (b) and 4 (
The parts corresponding to a) and (mouth) are given the same numbers.

In this prior art, a conductor 3 and an insulator 4 are formed in parallel in contact with each other, and then a transparent insulating substrate l and a conductor are exposed on the transparent electrode 2 at a cut portion between the transparent electrodes 2 and 2. 3. A p-i-n junction type or n-i-p junction type amorphous semiconductor layer 5 and Al, Ti are formed over the insulator 4.
, Ag back electrodes 6 are laminated in this order to the required thickness.

Next, as shown by broken lines in FIG. 6 (opening), conductor 3 insulator 4
A laser beam with a line width of 100 to 150 μm is projected so as to cover both sides, and the amorphous semiconductor layer 5 and back electrode 6 on these are evaporated and divided, and the edges of the separated back electrode 6 are They are allowed to hang down in a molten state and solidified while in contact with the surfaces of the conductor 3 and insulator 4, respectively.

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

In this prior art, a conductor and an insulator are formed next to each other, an amorphous semiconductor layer 5 and a back electrode 6 are laminated thereon, and then the conductor 3 and the insulator 4 are stacked. It is possible to simultaneously cut the conductor 3 and bring the edge of the back electrode 6 on the conductor 3 into electrical contact with the conductor 3.
Machining with a laser beam is required only once, which simplifies the process, and since the conductor 3 and insulator 4 are formed in contact with each other, the ineffective area between them can be removed, reducing the ineffective area. It can also be made narrower.

[Problem to be solved by the invention]

However, in this conventional technique, the series connection of each of the photovoltaic elements A, B, etc. is performed only at one edge of the backside electric bucket 6 that hangs down on the conductor 3. The conventional method shown in Figures 3 and 4 has the disadvantage that the contact area is smaller and the contact resistance increases compared to welding and connecting the entire circumference of the spot, and it is also more resistant to temperature changes than spot welding. However, linear welding has problems such as the strength of the joint being weak and the risk of wire breakage being high.

The present invention was made in view of the above circumstances, and its purpose is to simultaneously divide and connect photovoltaic elements in series in a single process using a laser beam, and to
The present invention provides a method for manufacturing a photovoltaic device that provides low contact resistance and high connection strength in series connections.

[Means to solve the problem]

The photovoltaic device according to the present invention has a conductive conductor formed in a strip shape on the surface of a transparent electrode that is separated for each region in which each photovoltaic element is formed on a transparent insulating substrate, and that is in contact with the surface of the transparent electrode along the vicinity of the cut portion. After forming the conductor 2 and the insulator, an amorphous semiconductor layer and a backside electrode layer are laminated in this order over the conductor 2 insulator and each cut transparent electrode, and the conductor 2 is laminated over the insulator and each cut transparent electrode. On the insulator, the amorphous semiconductor layer and the back electrode are melted and cut using an energy beam shaped asymmetrically with respect to the boundary line between the conductor and the insulator, and the conductor is It is characterized in that it includes a process of bringing the back electrodes of adjacent photovoltaic elements into electrical contact.

[Effect]

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

〔Example〕

The present invention will be specifically described below based on drawings showing its implementation state. Figures 1 (a) and 1 (opening) are schematic diagrams showing the main parts of a photovoltaic device manufactured by the method of the present invention, and 1 in the figure.
indicates a common light-transmitting insulating substrate made of glass or the like. This common light-transmitting insulating group Fi. 1, each photovoltaic element A, B, . . . is formed. Each photovoltaic element A,
B, . . . are transparent electrodes 2 using Sn02, ITO/SnOz, etc., respectively, on the above-mentioned common translucent insulating substrate 1.
A conductor 3 made of Af, Ag, etc., and an insulator 4 made of glass, etc. are formed on the conductor 3 and insulator 4 made of glass, etc., in contact with each other. A ρ-i-n junction type or n-i-p junction type amorphous semiconductor layer 5 and a backside electrode layer 6 made of Al or the like are laminated in this order, and the amorphous semiconductor layer is formed by laser beam projection. The layer 5 and the back electrode 6 are divided into each photovoltaic element A, B... and electrically isolated from each other by the insulator 4, and the adjacent photovoltaic elements A, B... The back electrode 6 of one of the photovoltaic elements A is connected to the transparent electrode 2 of the other photovoltaic element B via the conductor 3, and the photovoltaic elements A, B,... They are connected to each other in series.

Note that the connection between the back electrode 6 and the conductor 3 is made at approximately equal intervals over the entire area above the conductor 3 in the peripheral area of the laser beam projection section.

Next, the method for manufacturing such a photovoltaic device is shown in Figure 2 (a).
, (Ex), (C).

First, as shown in FIG. 2(A), SnOz. Or ITO
After laminating a transparent electrode 2 made of /SnOz or the like over the entire surface, the transparent electrode 2 was cut and separated into regions where the photovoltaic elements A, B, etc. were to be separated using a laser scribe. On each transparent electric bucket 2.2, a conductor 3 and an insulator 4 are formed in parallel and in contact with each other so as to span the entire length of one side edge along the cutting groove.

This conductor 3. The insulator 4 is made by applying a conductive paste mainly composed of Ag or an insulating paste mainly composed of glass to the transparent electrode 2 in a strip shape using a conventionally known pen drawing method or the like. Formed by firing.

Next, a p-i-n junction type or n-i- A p-junction type amorphous semiconductor layer 5 and a back electrode layer 6 made of Aj2, Ti, and Ag are laminated in this order to a required thickness.

Next, as shown in FIG. 2 (opening), an iris 8 having a predetermined aperture pattern in the optical path of the laser beams l and B, and a lens 7 for imaging the aperture pattern onto the back electrode 6.
is arranged, and a laser beam LB is projected in a pulsed manner with a width spanning both the conductor 3 and the insulator 4. The aperture pattern of the iris 8, that is, the laser beam projection pattern 9, is an asymmetrical pattern with respect to the boundary line between the conductor 3 and the insulator 4, as shown with hunting in FIG. 2(c), for example.
It has a rectangular part a, a circular part b, and a thin slit-like part C that connects both parts a and b, and the laser beam that has passed through the rectangular part a is on the back electrode 6 on the insulator 4 and also in the circular part. The laser beams that have passed through the shaped portions b are projected onto the back electrodes 6 on the conductor 3, and the slit-shaped portions C are projected onto the back electrodes 6 on the conductor 3.
．． The beams are projected onto the back electrodes 6 extending over both sides of the insulator 4, respectively.

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

In addition, the amorphous semiconductor layer 5 on the insulator 4 and the back electrode 6 are both evaporated and divided, and the edges of the divided back electrode 6 are melted into the traces of the evaporated amorphous semiconductor layer 5. It is allowed to hang down and solidify while in contact with the surface of the insulator 4.

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

In the above embodiment, the laser beam projection pattern 9 is made up of a series of rectangular portions a, circular portions b, and slit-like portions C. It may be a pattern in which fusing can be performed independently in a rectangular shape or in a rectangular shape on the insulator 4.

〔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 is formed on top of the conductor and insulator. Back electrodes are laminated and cut simultaneously on the conductor and insulator using an energy beam shaped asymmetrically with respect to the boundary line between the conductor and the insulator. The edge of the back electrode can be brought into electrical contact with the conductor in a spot-like manner, which not only requires processing with an energy beam only once, but also simplifies the process. The present invention has excellent effects such as a wide connection area between the back electrode and the conductor, high connection strength, low contact resistance, and high reliability.

[Brief explanation of drawings]

FIG. 1(A) is a cross-sectional structural diagram of a photovoltaic device manufactured by the method of the present invention, FIG. 1(B) is a plan view thereof, and FIG.
Figures (A), (C), and (C) are schematic cross-sectional views showing the main steps of the method of the present invention; Figure 3 (A) is a cross-sectional structural diagram of a photovoltaic device manufactured by the conventional method; Figure 3 (opening) is a plan view of the same, Figures 4 (a) and (opening) are schematic cross-sectional views showing the main steps of the conventional method, and Figure 5 (a) is a light produced by another conventional method. Cross-sectional structural diagram of the electromotive force device, Figure 5 (b)
6 is a plan view thereof, and FIGS. 6A and 6B are schematic cross-sectional views showing the main steps of another conventional method. 1... Transparent 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 patent Applicant: SANYO Electric Co., Ltd.

Claims (1)

[Claims] 1. A conductor and an insulator were formed in strips on the surface of a transparent electrode separated for each region where each photovoltaic element was formed on a transparent insulating substrate, in contact with each other along the vicinity of the cut portion. After that, an amorphous semiconductor layer and a back electrode are laminated in this order over the conductor, insulator, and each cut transparent electrode, and the amorphous semiconductor layer and back electrode are stacked on the conductor and insulator. , melting and cutting using an energy beam shaped into an asymmetrical shape with respect to the boundary line between the conductor and the insulator,
A method for manufacturing a photovoltaic device, comprising the step of electrically bringing a back electrode of another adjacent photovoltaic element into contact with the conductor.