KR101196387B1 - Integrated Thin Film Photovoltaic Module and Manufacturing Method Thereof - Google Patents

Abstract

The integrated thin film photovoltaic module according to the present invention includes a first cell and a second cell in which a lower electrode, a photoelectric conversion layer, and an upper electrode are stacked on a substrate, respectively, and the lower electrode and the second cell of the first cell. The lower electrode of the cell is separated by a lower electrode separation groove, and a plurality of through-holes are formed in the photoelectric conversion layer and the upper electrode of the first cell so as to be spaced apart from each other. A conductive material is filled in the through hole to connect with the lower electrode.

Description

Integrated Thin Film Photovoltaic Module and Manufacturing Method Thereof}

The present invention relates to an integrated thin film photovoltaic module and a method of manufacturing the same.

With the recent depletion of existing energy sources such as oil and coal, interest in alternative energy sources to replace them is increasing. Among them, solar energy is particularly attracting attention because it is rich in energy resources and has no problems with environmental pollution.

A photovoltaic module that converts sunlight into electrical energy has a junction structure of a p-type semiconductor and an n-type semiconductor such as a diode. When a light is incident on a photovoltaic module, (-) charged electrons and (+) charged electrons are generated by the action, and the current flows while they move.

The photovoltaic module is classified into a bulk type and a thin film type according to the thickness of the semiconductor, and the thin film type photovoltaic module includes a photoelectric conversion material having a thickness of several tens to several micrometers or less.

Currently, bulk silicon photovoltaic devices have been widely utilized primarily for ground power. However, in recent years, as the demand for bulk silicon photovoltaic modules soared, the price has increased due to the shortage of raw materials.

Therefore, in recent years, there is a need for an integrated thin film photovoltaic module that can be mass produced at low cost while having high energy conversion efficiency. However, since single-junction thin film photovoltaic modules have limited performance that can be achieved, high-definition and stability have been developed by developing double-junction thin film photovoltaic modules or triple-junction thin film photovoltaic modules stacked with a plurality of unit cells. The pursuit of stabilized efficiency is achieved. Double or triple junction thin film photovoltaic modules are called tandem photovoltaic modules.

In addition, research on the integration technology of the photovoltaic module has been conducted in an effort to increase the efficiency by reducing the invalid area of the thin film photovoltaic module.

The present invention has been devised in consideration of the problems and necessities of the prior art, and an object of the present invention is to provide a high efficiency integrated thin film photovoltaic module and a method of manufacturing the same, which can increase efficiency by reducing leakage current and reactive area of a photovoltaic module. It is done.

The technical objects to be achieved by the present invention are not limited to the above-mentioned technical problems, and other technical subjects which are not mentioned can be clearly understood by those skilled in the art from the description of the present invention .

An integrated thin film photovoltaic module according to an embodiment of the present invention includes a first cell and a second cell formed by stacking a lower electrode, a photoelectric conversion layer, and an upper electrode on a substrate, and the lower electrode of the first cell. And a lower electrode of the second cell are separated by a lower electrode separation groove, and a plurality of through holes are formed in the photoelectric conversion layer and the upper electrode of the first cell so as to be spaced apart from each other. A conductive material is filled in the through hole to connect with the lower electrode of the first cell.

In the integrated thin film photovoltaic module according to an embodiment of the present invention, the photoelectric conversion layer may include a first unit cell layer, a second unit cell layer, and an intermediate reflection layer positioned between the first unit cell layer and the second unit cell layer. It includes, and the sidewall of the through hole is coated with an insulating material.

In another embodiment, an integrated thin film photovoltaic module manufacturing method includes forming a lower electrode layer on a substrate; Forming a lower electrode separation groove separating the lower electrode layer into a first cell lower electrode layer and a second cell lower electrode layer; Forming a photoelectric conversion layer on the first cell and the second cell lower electrode layers; Forming an upper electrode layer on the photoelectric conversion layer; Forming a plurality of through holes spaced apart from each other through the photoelectric conversion layer and the upper electrode layer on the first cell lower electrode layer; Filling the through hole with a conductive material to connect the second cell upper electrode layer to the lower electrode layer of the first cell; And forming an upper separation groove separating the upper electrode layer and the photoelectric conversion layer so that a portion thereof passes over the lower electrode separation groove.

In another embodiment, an integrated thin film photovoltaic module manufacturing method includes forming a lower electrode layer on a substrate; Forming a photoelectric conversion layer on the lower electrode layer; Forming an upper electrode layer on the photoelectric conversion layer; Forming a separation groove separating the lower electrode layer, the photoelectric conversion layer and the upper electrode layer into a first cell lower electrode layer, a photoelectric conversion layer and an upper electrode layer and a second cell lower electrode layer, a photoelectric conversion layer and an upper electrode layer; Forming a plurality of spaced through holes penetrating the first cell photoelectric conversion layer and the upper electrode layer such that one side thereof contacts the separation groove; And filling the through hole with a conductive material to connect the second cell upper electrode layer to the lower electrode layer of the first cell.

In the method of manufacturing an integrated thin film photovoltaic module according to another embodiment of the present invention, forming the photoelectric conversion layer may include forming a first unit cell layer, an intermediate reflection layer, and a second unit cell layer.

In another embodiment, an integrated thin film photovoltaic module manufacturing method includes a sidewall of the through hole and a partial sidewall of the upper separation groove after forming the through hole and before filling the through hole with the conductive material. It further comprises the step of coating with an insulating material.

According to the present invention, the unit cells in the photovoltaic module are connected in series through point contact, thereby reducing the invalid area in the photovoltaic module, thereby increasing the module efficiency. In addition, according to the present invention, it is possible to reduce the leakage current of the tandem type photovoltaic module to increase its efficiency. In addition, according to the present invention, it is possible to prevent contamination and oxidation of the photoelectric conversion layer. In addition, the present invention can provide an integrated thin film photovoltaic module and a method of manufacturing the same.

1 is a perspective view of an integrated thin film photovoltaic module including photovoltaic cells connected in series via point contacts in accordance with a first embodiment of the present invention.
2A and 2B are cross-sectional views taken along lines aa 'and bb' of FIG. 1.
3A to 3G illustrate a manufacturing process of an integrated thin film photovoltaic module according to an embodiment of the present invention.
4 is an enlarged view of the dotted rectangle portion A of FIG. 1 in accordance with an embodiment of the present invention.
5A-5C illustrate the shape of a second line surrounding a through hole in accordance with an embodiment of the present invention.
FIG. 6A illustrates a perspective view of an integrated thin film photovoltaic module including photovoltaic cells connected in series via point contacts in accordance with a second embodiment of the present invention.
FIG. 6B is a cross-sectional view along the cc ′ line of FIG. 6A.
FIG. 6C is an enlarged view of the dotted rectangular portion B of FIG. 6A.
7A and 7B show the intensity distribution of the laser beam before and after passing through the homogenizer and the patterned surface accordingly.
Fig. 7C shows a cross section of the pattern formed by the laser beam passing through the homogenizer.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a detailed description of preferred embodiments of the present invention will be given with reference to the accompanying drawings. However, the embodiments of the present invention may be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. The shape and the size of the elements in the drawings may be exaggerated for clarity of explanation and the same reference numerals are used for the same elements and the same elements are denoted by the same quote symbols as possible even if they are displayed on different drawings Should be. In the following description, well-known functions or constructions are not described in detail to avoid unnecessarily obscuring the subject matter of the present invention.

1 shows a perspective view of a photovoltaic module comprising photovoltaic cells connected in series via point contact in accordance with a first embodiment of the present invention. In FIG. 1 and the following drawings, the shape of the lower electrode separation groove P1, the through hole P2, and the upper separation groove P3 is shown on the upper surface of the photovoltaic module, but for convenience of description, the shapes are May not be observed at the top surface.

The photovoltaic module according to the first embodiment of the present invention includes a substrate 100, a lower electrode 200, a photoelectric conversion layer 300, and an upper electrode 400.

Here, the photoelectric conversion layer 300 may include a plurality of unit cell layers. For example, the photoelectric conversion layer 300 may include two unit cell layers stacked or three unit cell layers. Each of the stacked unit cell layers is a basic unit layer for performing photoelectric conversion.

An intermediate reflective film may be inserted between the stacked unit cell layers to maximize the light confinement effect by enhancing internal reflection. For example, when the photoelectric conversion layer 300 includes two unit cell layers 310 and 330, an intermediate reflective layer 320 may be inserted between the two unit cell layers. Since the intermediate reflective layer 320 is positioned between two unit cell layers, the intermediate reflective layer 320 may include a translucent material, and the translucent material may include at least one of ZnO, ITO, SiO, or SnO ₂ .

When the photoelectric conversion layer 300 includes a plurality of unit battery layers, each of the photovoltaic cells UC1 and UC2 connected in series may have a plurality of unit cells 310 and 330 stacked thereon. The open voltage of the photovoltaic cells UC1 and UC2 is the sum of the open voltages of the stacked unit cells 310 and 330, and the short circuit current of the unit cells UC1 and UC2 is a short circuit current of the stacked unit cells. Has the minimum short-circuit current value.

Hereinafter, an embodiment of the present invention will be described using the photoelectric conversion layer 300 including two unit cell layers 310 and 320 and the intermediate reflection film 320 as an example. It may also be applied to the case of including only one unit cell layer.

As shown in FIG. 1, the lower electrode isolation groove P1 is formed through the lower electrode 200 to prevent a short circuit between the lower electrodes 200 of each photovoltaic cell. The lower electrode separation groove P1 may be formed along, for example, a straight first line 220.

A plurality of through holes P2 penetrating the photoelectric conversion layer 300 and the upper electrode 400 are spaced apart in a point shape having a predetermined width rather than a straight shape, and are provided on one side of the lower electrode separation groove P1. Is formed. The through hole P2 may be filled with a conductive material so that the upper electrode 400 of the second cell and the lower electrode 200 of the first cell may be connected through the conductive material.

Adjacent photovoltaic cells UC1 and UC2 may be connected in series through a conductive material filled in the through hole P2. In other words, the lower electrode 200 of the first cell UC1 and the upper electrode 400 of the second cell UC2 are connected through a conductive material filled in the through hole P2, and thus, the first cell UC1. And the second cell UC2 may be connected in series.

This is illustrated in Figure 2A, which is a cross sectional view along line a-a 'of the photovoltaic module of Figure 1. As shown in FIG. 2A, the through hole P2 is filled with a conductive material 600. The conductive material 600 contacts the lower electrode 200 at the bottom surface of the through hole P2 and the upper electrode 400 at the upper side of the through hole P2. Accordingly, adjacent cells UC1 and UC2 may be connected in series to each other through the spaced through holes P2.

In addition, according to the exemplary embodiment of the present invention, even if the intermediate reflective film 320 is a conductive material, leakage current that may be generated by direct contact between the conductive material 600 filled in the through hole P2 and the intermediate reflective film 320 may be caused. Can be prevented. This may be accomplished by forming the insulating film 500 on the sidewall of the through hole P2, as shown in FIG. 2A. Therefore, the conductive material 600 filled in the through hole P2 is in an electrically insulated state from the intermediate reflective layer 320, thereby preventing the occurrence of leakage current. As a result, the fill factor of the photovoltaic module can be prevented from being reduced due to the leakage current. Although FIG. 2A illustrates that the insulating film 500 is formed on the entire sidewall of the through hole P2, the insulating film 500 may be formed only on the sidewall of the intermediate reflective film formed of the conductive material. The insulating film 500 may be omitted when the photoelectric conversion layer 300 includes only one unit cell layer or when the intermediate reflective film 320 is not a conductive material.

In the present specification, it is illustrated that the through hole P2 is in the form of a point, but this is only an example, and if the plurality of through holes P2 are spaced apart from each other, this is within the scope of the present invention. For example, the through hole P2 may be a segmented straight line extending in one direction.

As described above, the photovoltaic module according to the embodiment of the present invention includes a plurality of cells UC1 and UC2 each including a lower electrode 200, a photoelectric conversion layer 300, and an upper electrode 400 and connected in series with each other. It may include.

The upper isolation groove P3 is formed through the photoelectric conversion layer 300 and the upper electrode 400, thereby distinguishing the photovoltaic cells UC1 and UC2. The upper separation groove P3 is formed to overlap the path of the lower electrode separation groove P1 except for enclosing the point-shaped through hole P2 in a predetermined shape. For example, the upper separation groove P3 may be formed along the second line 420.

A cross-sectional view along the line b-b 'of the photovoltaic module of Figure 1 is shown in Figure 2b for the understanding of the present invention. As shown in FIG. 1, in the portion where the upper separation groove P3 passes over the lower electrode separation groove P1, the upper separation groove P3 extends to the upper surface of the substrate 100. On the other hand, as shown in Figure 2b, in the portion where the upper separation groove (P3) does not pass over the lower electrode separation groove (P1), the upper separation groove (P3) is the upper surface of the lower electrode (200) Only extends. The upper separation groove P3 is formed through the photoelectric conversion layer 300 and the upper electrode 400, but the lower electrode 200 is already formed in the portion where the lower electrode separation groove P1 is formed. It is because it was removed by the separation groove (P1).

As described above, since the first line 220 in which the lower electrode separation groove P1 is formed and the second line 420 in which the upper separation groove P3 is formed overlap each other except for a specific region, The invalid area of the photovoltaic module according to the embodiment can be reduced. In addition, since the through-holes P2 for serially connecting the unit cells in the photovoltaic module are formed at predetermined intervals in the form of point contacts, an invalid area of the photovoltaic module may be reduced. Therefore, since the area of the effective area is increased compared to the same area, an improvement in the relative current value can be seen.

In addition, according to the present invention, the photoelectric conversion layer 300 may be prevented from being exposed to the air to be oxidized or contaminated. Therefore, efficiency degradation of the photovoltaic module generated by the deterioration of the photoelectric conversion layer 300 due to the contamination or oxidation can be prevented.

In general, the electrode layer and the photoelectric conversion layer are generally formed in a vacuum state, and laser patterning for forming the lower electrode separation groove P1, the through hole P2, and the upper separation groove P3 is performed in the air. As described above, according to the present invention, after the photoelectric conversion layer 300 and the upper electrode 400 are formed, the through hole P2 and the upper separation groove P3 are formed. Therefore, the substrate 100 having the lower electrode 200, the photoelectric conversion layer 300, and the upper electrode 400 is exposed to the air to form the through hole P2 and the upper separation groove P3. In this case, since the upper electrode 400 is formed on the photoelectric conversion layer 300, the photoelectric conversion layer 300 is directly exposed to the atmosphere while being exposed to the air for laser patterning, and the like, so that oxidation or contamination may be prevented. Can be.

Hereinafter, a manufacturing process of a photovoltaic module including photovoltaic cells connected in series with each other through a point contact according to the first embodiment of the present invention will be described in detail with reference to FIGS. 3A to 3G. 3A-3G show three photovoltaic cells, but the photovoltaic module of the present invention may include a greater number of cells.

As shown in FIG. 3A, a substrate 100 is prepared. The substrate 100 may be an insulating transparent substrate. When the photovoltaic module according to the embodiment of the present invention performs photoelectric conversion by light irradiated from the upper electrode 400 side, the substrate 100 may be an opaque insulating substrate. In addition, the substrate 100 may be a flexible substrate.

As shown in FIG. 3B, a lower electrode 200 is formed on the substrate 100. The lower electrode 200 may be a transparent electrode including tin oxide (SnO ₂ ), zinc oxide (ZnO), indium tin oxide (ITO), or the like. When the photovoltaic module according to the embodiment of the present invention performs photoelectric conversion by light irradiated from the upper electrode 400, the lower electrode 200 may be an opaque electrode.

As shown in FIG. 3C, the laser is irradiated to the lower electrode 200 side or the substrate 100 side in the atmosphere so that the lower electrode 200 is scribed. Accordingly, the lower electrode separation groove P1 penetrating the lower electrode 200 may be formed along the first linear line 220, for example. That is, since the lower electrodes 200 are separated from each other by the lower electrode separation grooves P1, shorting between the adjacent lower electrodes 200 is prevented.

As shown in FIG. 3D, a photoelectric conversion layer 300 including a first unit cell layer 310, an intermediate reflection layer 320, and a second unit cell layer 330 is formed on the lower electrode 200. do. In this case, the photoelectric conversion layer 300 may also be formed in the lower electrode separation groove P1.

The first unit cell layer 310 and the second unit cell layer 330 may include any material that converts incident light energy into electrical energy. For example, the first and second unit cell layers 310 and 330 may include a photoelectric conversion material capable of forming a thin film type photovoltaic module such as amorphous silicon, compound, organic, and dye-sensitized solar cells. have.

The intermediate reflection layer 320 reflects a part of the light passing through the unit cell layer in which the light is incident first among the first unit cell layer and the second unit cell layer, and reflects the light to the unit cell layer in which the light enters first. Pass it through the unit cell layer. Accordingly, the amount of light absorbed by the unit cell layer in which the light first enters is increased, so that the current generated in the unit cell layer can be increased.

In this case, the optical bandgap of the unit cell layer close to the light incident side of the first and second unit cell layer may be larger than the optical bandgap of the remaining unit cell layer. For example, when light is incident through the substrate 100, the optical band gap of the first unit cell layer is larger than the optical band gap of the second unit cell layer. This is because light having a high energy density has a short transmission distance, and a material having a large optical band gap absorbs light having a short wavelength.

As shown in FIG. 3E, an upper electrode 400 is formed on the photoelectric conversion layer 300. The upper electrode 400 may include a conductive material which functions well as a light reflecting material. For example, the conductive material forming the upper electrode 400 may be at least one selected from the group consisting of Al, Ag, Au, Cu, Zn, Ni, Pt, (Pd) or chromium (Cr), or the like.

When the photovoltaic module according to the embodiment of the present invention performs photoelectric conversion by light irradiated from the upper electrode 400 side, the upper electrode 400 may be formed of a transparent conductive material. In this case, the lower electrode 200 may include a conductive material for reflecting light and serving as an electrode.

As shown in FIG. 3F, the laser is irradiated to the substrate 100 side or the upper electrode 400 side in the air to scribe the photoelectric conversion layer 300 and the upper electrode 400. As a result, a plurality of through holes P2 penetrating the photoelectric conversion layer 300 and the upper electrode 400 are spaced apart from each other. The through-holes P2 may be formed in plural on one side of the lower electrode separation groove P1 spaced apart from each other as a point shape having a predetermined width. The through-holes P2 formed in this way may be connected in series between the cells in the photovoltaic module.

As shown in FIGS. 2A and 2B, an insulating film 500 is coated on the inner sidewall of the through hole P2. The insulating film 500 may be formed only in a portion where the intermediate reflective film of the photoelectric conversion layer 300 is exposed. In addition, the insulating film 500 may be coated on a portion where the intermediate reflective film and the conductive layer in contact with the intermediate reflective film are exposed. The insulating layer 500 is to prevent leakage of current that may occur when the conductive layer existing in the photoelectric conversion layer 300 comes into contact with a conductive material filled in the through hole P2.

The insulating layer may include an insulating paste such as TiO ₂ nanoparticles, resin, or carbon paste. The insulating layer 500 may be coated on the sidewall of the through hole P2 by a printing method such as screen printing, inkjet printing, or laser printing. In addition, a UV curing agent may be used as the insulating material. Therefore, the insulating film 500 may be formed by printing a UV curing agent on the sidewall of the through hole P2 and then performing UV curing. Accordingly, even when the intermediate reflective film 320 is conductive, leakage current can be prevented from being generated through the intermediate reflective film 320.

Next, as shown in FIGS. 2A and 2B, the conductive material 600 is filled in the through hole P2 having the insulating film 500 coated on the sidewall. The conductive material 600 contacts the lower electrode 200 at the bottom surface of the through hole P2 and contacts the upper electrode 400 at the upper side of the through hole P2. It is filled. The conductive material 600 may be filled in the through hole P2 by applying a conductive paste such as silver paste or a conductive polymer by a printing method such as screen printing, inkjet printing, or laser printing.

As shown in FIG. 3G, the laser is irradiated in the air to scribe the photoelectric conversion layer 300 and the upper electrode 400. Accordingly, an upper separation groove P3 penetrating the photoelectric conversion layer 300 and the upper electrode 400 may be formed along the second line 420. The second line 420 follows the same path as the first line 220 in which the lower electrode separation groove P1 is formed except for enclosing the through-hole P2 having a point shape. That is, the upper separation groove P3 is formed to pass over the lower electrode separation groove P1 except for the portion surrounding the through hole P2. Unit cells UC1 and UC2 are defined through the upper separation groove P3.

According to another embodiment of the present invention, the upper electrode 400 may be formed by printing a patterned upper electrode in a non-vacuum state. For example, the upper electrode patterned in the shape of the through hole P2 and the upper separation groove P3 is formed on the photoelectric conversion layer 300 by a printing method such as laser printing, inkjet printing, and screen printing in a non-vacuum state. Can be formed. By forming the patterned upper electrode in the air rather than in the vacuum state, manufacturing cost can be reduced.

In this case, the through hole P2 may be formed after the upper separation groove P3 is formed. In addition, the insulating film 500 and the conductive material 600 may be formed in the through hole P2 after forming the upper separation groove P3 and the through hole P2.

The lower electrode separation groove P1 is formed along the first line 220 and the upper separation groove P3 is formed along the second line 420 in the manufacturing process of the photovoltaic module according to the embodiment of the present invention, But it is also possible that the lower electrode separation groove P1 is formed along the second line 420 and the upper isolation groove P3 is formed along the first line 220. [

In this case, the ratio of the length of the upper separation groove and the lower electrode separation groove to the length of the first line may be 0.70 or more and 0.96 or less. If the ratio is less than 0.70, the invalid region increases, so that the effect of sufficient current rise cannot be obtained, and the manufacturing time can increase. When the ratio is greater than 0.96, the path of electrons increases to increase resistance and Joule heat, thereby reducing the fill factor of the photovoltaic module.

Also, in the manufacturing process of the photovoltaic module according to the embodiment of FIG. 1 and the above-described embodiment, the width of the lower electrode separation groove P1 is shown to be wider than the width of the upper separation groove P3. The width of the lower electrode separation groove P1 may be the same as or smaller than the width of the upper separation groove P3.

In a photovoltaic module including photovoltaic cells connected in series with each other through point contacts according to an embodiment of the present invention, it is important to form a through hole P2 in an appropriate number. If the number of the through holes P2 is too large, the invalid area increases as in the case of linear laser scribing, and thus, sufficient current rise effect cannot be obtained. In addition, since the upper separation groove P3 formed by laser scribing is formed to surround the through hole P2, a manufacturing time may increase. If the number of the through holes P2 is too small, the path through which electrons should move becomes large, and thus, the resistance and joule rows may increase, thereby reducing the fill factor. Therefore, it is necessary to optimize the distance between the plurality of through holes P2 and the number of the through holes P2 formed between two adjacent unit cells.

An enlarged view of the dotted rectangle portion A of FIG. 1 is shown in FIG. d represents the distance between two adjacent through holes P2. x represents the distance between the first line 220 and the through hole P2. P2h represents the foot of the waterline which has fallen from the through hole P2 to the first line 220. J13 represents a point where the lower electrode separation groove P1 and the upper separation groove P3 branch off. r represents the distance between P2h and J13.

As shown in FIG. 4, the second line 420 overlaps the first line 220 except for a region surrounding the through hole P2. That is, the second line 420 branches from the first line 220 from the point J13 separated by a predetermined distance r on the first line 220 from the foot P2h of the repair line, and passes through the through hole. It may return to the other point surrounding P2 and separated by a predetermined distance r on the first line 220 from the foot P2h of the repair line.

In this case, the second line 420 may be located in the middle of the outermost point P3p farthest from the first line 200 and the foot P2h of the waterline. The distance between the feet P2h of the repair can be represented by 2x.

In the photovoltaic module according to the first embodiment of the present invention, the distance 2x may have a size of 200 μm or more and 300 μm or less. By maintaining the distance 2x within the range, a short circuit between the lower electrode separation groove P1, the through hole P2, and the upper separation groove P3 can be prevented while the size of the invalid region is not unnecessarily increased. Can be.

In the photovoltaic module according to the first embodiment of the present invention, the distance d between the through holes P2 is preferably 1 mm or more and 5 cm or less. At this time, the ratio of the distance between the through-hole (P2), the distance (2x) of the distance (d) between, that is, the second line 420 and to the repair (P2h) is 4x10 ^{- 3} above 300x10 ^- it can be ³ or less. If the distance d is less than 1 mm, the invalid region is increased, so that the effect of sufficient current rise cannot be obtained and the manufacturing time can be increased. If the distance d is greater than 5 cm, the path through which electrons should move to the lower electrode increases, thereby increasing the resistance and Joule heat, thereby reducing the fill factor of the photovoltaic module.

 The unit cells UC1 and UC2 of the photovoltaic module according to the embodiment of the present invention have a width of 6 mm or more and 15 mm or less. If the cell width is smaller than 6 mm, the invalid area is increased and the value of the open voltage Voc generated per one module is increased, thereby increasing the installation cost. If the cell width is larger than 15 mm, the resistance becomes large and efficiency decreases.

Laser scribing of the effective region in the photovoltaic module according to an embodiment of the present invention, when the region in which the semiconductor and the conductor are removed and the remaining photoelectric conversion is performed for the edge isolation in the module is referred to as the effective region. The ratio of the invalid area by may have values of approximately 0.007% or more and 1.5% or less.

In the photovoltaic module according to the first embodiment of the present invention, the shape in which the second line 420 surrounds the through hole P2 has electrons from the through hole P2 to the second line 420. The distance to travel can be determined to be as short as possible. Heat generation may be minimized when the moving distance from the through hole P2 to the upper separation groove P3 surrounding the through hole P2 is short. In addition, the shape may be formed evenly distance from the through-hole (P2) to minimize the invalid area generated therefrom. For example, the upper separation groove P3 surrounding the through hole P2 may have a form of a part of a circle. For example, the second line 420 surrounds the through hole P2 in the form of a partial circle.

As shown in FIG. 4, an insulating film 500 is coated on the sidewall of the through hole P2, and a conductive material 600 is filled in the through hole P2. 4, the conductive material 600 is formed to be wider than the width of the through hole P2 at the upper side of the through hole P2, which indicates that the conductive material 600 is formed at the upper side of the upper electrode 400. To illustrate contact with When the conductive material 600 is filled in the through hole P2, the conductive material 600 may be formed in contact with the upper electrode surrounded by the second line 420.

5A to 5C illustrate another example of a shape in which the upper separation groove P3 surrounds the through hole P2 in the photovoltaic module according to the embodiment of the present invention.

FIG. 5A shows that the second line 420 diverges from the first line 220 at the branch point J13 and surrounds the through hole P2 along a portion of the ellipse. In this case, the through hole P2 may be located in the middle of the foot P2h of the waterline and the outermost point P3p of the second line 420. When the second line 420 surrounds the through hole P2 along an ellipse or part of a circle, the distance from the through hole P2 to the second line 420 is somewhat uniform and is ineffective. Can be reduced.

5B and 5C illustrate partial pentagrams and triangles as the second line 420 surrounds the through hole P2. Even when the second line 420 surrounds the through hole P2 in this shape, an invalid area can be reduced, and the distance from the through hole P2 to the second line 420 is to some extent. It can be seen that uniformity.

However, the shape shown is merely an example, and in the photovoltaic module according to an embodiment of the present invention, the specific shape may be a part of a polygon including a pentagon or a triangle. In this case, each of the inner angles of the polygon must be smaller than 180 ° to effectively reduce the invalid area. In addition, the polygon is preferably symmetrical with respect to a straight line connecting the foot P2h of the waterline, the through hole P2 and the outermost point P3p. In addition, it is preferable that each of the interior angles of the polygons is greater than or equal to 90 °. If the interior angles of the polygons are acute, the laser beam may be concentrated at the same vertex, causing excessive patterning or damaging the photoelectric conversion layer and the electrode layer by heat. Because there is.

However, the angle θ formed between the first line 220 and the second line 420 at the branch point J13 may have a value of 90 ° or more and 135 ° or less. For example, when the shape is part of a circle or ellipse, an angle formed between the tangent line at the branch point J13 of the circle or ellipse and the first line 220 has a value of 90 ° or more and 135 ° or less. When the shape is the aforementioned polygon, the outer angle of the polygon at the branch point J13 may have a value of 90 ° or more and 135 ° or less. When the angle θ is smaller than 90 °, the distance between the second line 420 and the through hole P2 becomes far and does not reduce the invalid area efficiently. In addition, even when the angle θ is greater than 135 °, the width of the second line 420 surrounding the through hole P2 is widened, thereby reducing the effect of reducing the invalid area.

In addition, depending on the shape of the shape surrounding the through hole P2, the point shape of the through hole P2 may also have a circular, elliptical or polygonal shape. The shape of the through hole P2 may be implemented by using a mask having a predetermined pattern to selectively transmit a laser beam passing through the homogenizer as described with reference to FIGS. 7A to 7C. As such, by matching the shape of the through-hole P2 with the shape surrounding the through-hole P2, the distance from the through-hole P2 to the second line 420 surrounding electrons through the lower electrode. Can be reduced and made uniform.

FIG. 6A illustrates a perspective view of a photovoltaic module including photovoltaic cells connected in series via point contact in accordance with a second embodiment of the present invention. Hereinafter, details of the photovoltaic module according to the first embodiment of the present invention described with reference to FIGS. 1 to 3G will be omitted, and the second embodiment of the present invention differs from the first embodiment. Explain mainly.

In the photovoltaic module according to the second embodiment of the present invention, the paths of the lower electrode isolation groove and the upper isolation groove described in FIG. 1 coincide with each other. It is the same as the upper separation groove is formed to pass over the lower electrode separation groove.

That is, in the photovoltaic module according to the second embodiment of the present invention, a separation groove P1 penetrating the lower electrode 100, the photoelectric conversion layer 300, and the upper electrode 400 to be separated into a plurality of cells is formed. have.

A plurality of through-holes P2 penetrating the photoelectric conversion layer 300 and the upper electrode 400 are separated from each other in a point shape having a predetermined width rather than a straight line, and formed on one side of the separation groove P1. . At this time, one side of the through hole (P2) is formed to contact the separation groove (P1). That is, the through hole P2 has a shape in which one side thereof is cut by the separation groove P1. For example, in the photovoltaic module according to the second embodiment of the present invention, the through hole P2 may have a cylindrical (or cylindrical) shape in which one surface is cut by the separation groove P1.

The through hole P2 may be filled with a conductive material so that the upper electrode 400 of the second cell and the lower electrode 200 of the first cell may be connected through the conductive material. In this case, since there is no boundary between the through hole P2 and the separation groove P1, the conductive material may be filled not only in the through hole P2 but also in the separation groove P1 in contact with the through hole P2. have.

A cross-sectional view along line c-c 'of the photovoltaic module shown in Figure 6a is shown in Figure 6b. As shown in FIG. 6B, one side of the through hole P2 contacts the separation groove P1 so that the separation groove P1 and the through hole P2 form one space. However, only the lower electrode layer 100 is exposed under the through hole P2.

The conductive material 600 is filled in the through hole P2 and the separation groove P1 in contact with the through hole P2. The conductive material 600 contacts the lower electrode 200 of one cell at the bottom surface of the through hole P2 and the upper electrode of the cell adjacent to the one cell at the upper side of the through hole P2 ( 400). In this case, care should be taken not to contact the conductive material 600 with the upper electrode 400 of the other cell. This is because, unlike in the first embodiment, the upper separation groove is not formed to surround the through hole P2, so that the upper electrodes of two adjacent cells may be shorted to each other by the conductive material 600.

In addition, when the intermediate reflective film 320 is a conductive material, the insulating film 500 may be included on the sidewall of the through hole P2 and the sidewall of the separation groove filled with the conductive material to prevent current leakage by the intermediate reflective film. Can be.

An enlarged view of the dotted rectangle portion B in FIG. 6A is shown in FIG. 6C. As shown in FIG. 6C, the through hole P2 is integrated in contact with the separation groove P1 at one side. The conductive material 600 is filled in the through hole P2 and the separation groove P1 in contact with the through hole P2. In this case, in order to prevent the conductive material from coming into contact with the intermediate reflective film of the photoelectric conversion layer 300, an insulating film 500 is coated on the sidewall except for one side of the through hole P2. In addition, a portion of the sidewall of the separation groove P1 facing the through hole P2 may be coated with the insulating layer 500 to prevent the conductive material from contacting the intermediate reflective layer.

In this case, in order to ensure that the conductive material 600 is not in contact with the intermediate reflective film 320, the insulating film 500 is coated with a width wider than the width of the conductive material 600 is formed. However, this is only an example and the insulating film 500 may have any shape as long as it prevents the conductive material 600 from coming into contact with the intermediate reflective film of two adjacent cells.

In the above description, the separation groove P1 is formed in a straight shape and the through hole P2 is formed on one side of the separation groove P1. However, the separation groove P1 may be formed to surround one side of the through hole P2 only in a portion where the through hole P2 is formed while following the path connecting the through holes P2 spaced apart from each other. .

As described above, according to the second embodiment of the present invention, since the paths of the lower electrode isolation groove and the upper isolation groove coincide with each other, the invalid area can be reduced. Therefore, since the area of the effective area is increased compared to the same area, an improvement in the relative current value can be seen.

In the manufacturing process of the photovoltaic module according to the above-described embodiment of the present invention, at least one of the separation grooves P1 and P3 and the through hole P2 may be formed by laser scribing. A laser processing machine (not shown) that performs such laser scribing may include a homogenizer so that the intensity distribution of the laser beam oscillated by the laser oscillator is uniform in the area irradiated. The homogenizer may be made of an optical fiber cable using a combination of spherical lenses or total reflection characteristics.

Referring to FIGS. 7A and 7B, when a laser beam having a Gaussian intensity distribution oscillated in a laser oscillator passes through a homogenizer, a laser beam having a uniform intensity distribution is obtained. 7A and 7B, a pattern surface using a laser beam having a Gaussian intensity distribution (FIG. 7A) passes through a homogenizer to a pattern surface using a laser beam having a uniform intensity distribution (FIG. 7B). It can be seen that it is very irregular.

That is, when the intensity distribution of the laser beam is uniform, the pattern surface of the separation grooves formed by irradiating the laser beam is formed substantially uniformly. As a result, burrs may be minimized in the sidewalls of the separation grooves and / or the through holes P1, P2, and P3, and thus an integrated thin film photovoltaic module having improved efficiency may be manufactured. In addition, by using the laser beam passed through the homogenizer as described above, laser power is applied to implement desired insulation properties, thereby preventing the characteristics of the surrounding photoelectric conversion layer and the electrode from being changed.

In addition, the laser processing machine may include a mask having a predetermined pattern formed to selectively transmit the laser beam passing through the homogenizer. Accordingly, only the region of the laser beam showing a uniform intensity distribution of a desired degree can be used to form the separation groove or the through hole.

7C shows a cross section of a separation groove or through hole pattern formed in accordance with an embodiment of the invention. At this time, the ratio of the step height h of the bottom surface of the pattern to the width W of the pattern is preferably 5% or more and 10% or less. When the ratio of the step h to the width W of the pattern is greater than 10%, the edge of the pattern may not be sufficiently removed, thereby causing leakage current. In order to implement the ratio of the step h to the width W of the pattern smaller than 5%, excessive laser power may be applied to change the characteristics of the surrounding photoelectric conversion layer and the electrode.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. will be. Therefore, it should be understood that the above-described embodiments are to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than the foregoing description, It is intended that all changes and modifications derived from the equivalent concept be included within the scope of the present invention.

100: substrate
200: lower electrode
220: First line
300: photoelectric conversion layer
310: first unit cell layer
320: middle reflective film
330: second unit cell layer
400: upper electrode
420: second line

Claims (33)

An integrated thin film photovoltaic module comprising a first cell and a second cell in which a lower electrode, a photoelectric conversion layer, and an upper electrode are stacked on a substrate,
The lower electrode of the first cell and the lower electrode of the second cell are separated by the lower electrode separation groove,
The photoelectric conversion layer and the upper electrode of the first cell are formed with a plurality of through holes spaced apart from each other,
A conductive material is filled in the through hole to connect the upper electrode of the second cell to the lower electrode of the first cell.
The photoelectric conversion layer may include a first unit cell layer, a second unit cell layer, and an intermediate reflective film positioned between the first unit cell layer and the second unit cell layer.
Integrated thin film photovoltaic module. delete The method of claim 1,
Integrated thin film photovoltaic module, characterized in that the insulating film is coated on the sidewall of the through hole. The method of claim 1,
The photoelectric conversion layer and the upper electrode of the first cell and the photoelectric conversion layer and the upper electrode of the second cell are separated by an upper separation groove, the upper separation groove passes over the lower electrode separation groove,
Integrated thin film photovoltaic module, characterized in that one side of the through hole is in contact with the upper separation groove. 5. The method of claim 4,
And the photoelectric conversion layer includes a first unit cell layer, a second unit cell layer, and an intermediate reflector disposed between the first unit cell layer and the second unit cell layer. The method of claim 5, wherein
An insulating film is coated on the sidewall of the through hole except the one side and the sidewall of the second cell side of the upper separation groove so that the conductive material is prevented from contacting the intermediate reflective film of the first cell and the second cell. Integrated thin film photovoltaic module. The method of claim 3,
The photoelectric conversion layer and the upper electrode of the first cell and the photoelectric conversion layer and the upper electrode of the second cell are separated by an upper separation groove, and a part of the upper separation groove passes over the lower electrode separation groove. Integrated thin film photovoltaic module. The method of claim 7, wherein
Integrated thin film photovoltaic module, characterized in that the separation groove of one of the lower electrode separation groove and the upper separation groove has a straight shape. 9. The method of claim 8,
And the ratio of the length of the portion of the upper separation groove passing over the lower electrode separation groove to the length of the one separation groove is 0.70 or more and 0.96 or less. 9. The method of claim 8,
In the region where the upper separation groove does not pass over the lower electrode separation groove, the other separation groove of the lower electrode separation groove and the upper separation groove has a partial circle or ellipse shape. Power module. The method of claim 10,
Integrated thin film photovoltaic module, characterized in that the angle formed by the tangent of the circle or ellipse and the straight line at the branch point where the other separation groove is branched from the straight line is 90 ° or more and 135 ° or less. 9. The method of claim 8,
Integrated thin film photovoltaic module, characterized in that the other separation groove of the lower electrode separation groove and the upper separation groove has a partial polygonal shape in the region where the upper separation groove does not pass over the lower electrode separation groove. . The method of claim 12,
The outer angle of the polygon at the branching point where the other separation groove is diverged from the straight line is 90 ° or more and 135 ° or less,
And wherein each of the interior angles of the polygon is less than 180 °. 9. The method of claim 8,
The through hole may be formed by the male foot of the through hole lowered on the straight line in the region where the upper separation groove does not pass over the lower electrode separation groove and the other separation groove of the upper separation groove and the lower electrode separation groove. Integrated thin film photovoltaic module, characterized in that located in the center between the outermost point. 8. The method according to claim 6 or 7,
Integrated thin film photovoltaic module, characterized in that the width of each of the first cell and the second cell is 6mm or more and 15mm or less. 8. The method according to claim 6 or 7,
Integrated thin film photovoltaic module, characterized in that the distance between two adjacent through holes of the through hole is 1mm or more and 5cm or less. 8. The method according to claim 6 or 7,
And a ratio of an invalid area formed by the lower electrode separation groove, the through hole, and the upper separation groove to an effective area in the integrated thin film photovoltaic module is 0.007% or more and 1.5% or less. 9. The method of claim 8,
Two adjacent through holes of the through holes are spaced apart by a predetermined distance,
The ratio of the distance between the predetermined distance the rectilinear to the through-hole perpendicular to the upper separation grooves and the lower electrode separation grooves of the other of the separation groove of the outermost point of which fell in about a is 4x10 ^{- 3} above 300x10 ^- Integrated thin film photovoltaic module, characterized in that ³ or less. 8. The method according to claim 6 or 7,
Integrated thin film photovoltaic module, characterized in that the shape of the cross-section of the through hole is a circle, ellipse or polygon. 8. The method according to claim 6 or 7,
And the ratio of the step height of the bottom surface to the width of at least one of the lower electrode separation groove, the through hole and the upper separation groove is 5% or more and 10% or less. Forming a lower electrode layer on the substrate;
Forming a lower electrode separation groove separating the lower electrode layer into a first cell lower electrode layer and a second cell lower electrode layer;
Forming a photoelectric conversion layer on the first cell and the second cell lower electrode layers;
Forming an upper electrode layer on the photoelectric conversion layer;
Forming a plurality of through holes spaced apart from each other through the photoelectric conversion layer and the upper electrode layer on the first cell lower electrode layer;
Filling the through hole with a conductive material to connect the second cell upper electrode layer to the lower electrode layer of the first cell; And
And forming a portion of an upper separation groove that separates the upper electrode layer and the photoelectric conversion layer so that a portion thereof passes over the lower electrode separation groove.
Forming the photoelectric conversion layer is:
Forming a first unit cell layer, an intermediate reflection film, and a second unit cell layer;
Integrated thin film photovoltaic module manufacturing method. delete The method of claim 21,
After forming the through hole and before filling the through hole with the conductive material,
The method of manufacturing an integrated thin film photovoltaic module, further comprising coating an insulating material on the sidewall of the through hole. Forming a lower electrode layer on the substrate;
Forming a photoelectric conversion layer on the lower electrode layer;
Forming an upper electrode layer on the photoelectric conversion layer;
Forming a separation groove separating the lower electrode layer, the photoelectric conversion layer and the upper electrode layer into a first cell lower electrode layer, a photoelectric conversion layer and an upper electrode layer and a second cell lower electrode layer, a photoelectric conversion layer and an upper electrode layer;
Forming a plurality of spaced through holes penetrating the first cell photoelectric conversion layer and the upper electrode layer such that one side thereof contacts the separation groove; And
Filling the through hole with a conductive material to connect the second cell upper electrode layer to the lower electrode layer of the first cell;
Forming the photoelectric conversion layer is:
Forming a first unit cell layer, an intermediate reflection film, and a second unit cell layer;
Integrated thin film photovoltaic module manufacturing method. delete 25. The method of claim 24,
After forming the through hole and before filling the through hole with the conductive material,
Coating an insulating material on the sidewall of the through hole except the one side and the sidewall of the second cell side of the upper separation groove to prevent the conductive material from contacting the intermediate reflective film of the first and second cells. Integrated thin film photovoltaic module manufacturing method characterized in that it further comprises. 25. The method according to claim 21 or 24,
Filling the conductive material in the through-holes is a method of manufacturing an integrated thin film photovoltaic module, characterized in that performed by a printing method such as laser printing, inkjet printing or screen printing. The method of claim 23 or 26,
Coating the insulating material is performed by a printing method such as laser printing, inkjet printing or screen printing. 29. The method of claim 28,
The insulating material is a UV curing agent,
The coating of the insulating material may include UV curing after printing the UV curing agent. The method of claim 21,
At least one of the lower electrode separation groove, the through hole and the upper separation groove is formed by laser scribing. The method of claim 21,
At least one of the lower electrode separation groove, the through hole, and the upper separation groove is formed by irradiating a laser beam passing through a homogenizer for uniformizing the intensity distribution of the laser beam. Manufacturing method. 25. The method according to claim 21 or 24,
The through-holes are formed by irradiating a laser beam passing through a homogenizer for uniformizing the intensity distribution of the laser beam and a mask in which a predetermined pattern is formed. 25. The method according to claim 21 or 24,
The upper electrode layer is a method of manufacturing an integrated thin film photovoltaic module, characterized in that formed by patterning by a printing method such as laser printing, inkjet printing or screen printing.

Images