CN102651362A - Series integrated photoelectric module and producing method thereof - Google Patents

Abstract

The invention relates to a tandem integrated photoelectric module, which comprises: a first cell and a second cell respectively laminated on a substrate to form a lower electrode, a photoelectric conversion layer and an upper electrode, and the photoelectric conversion layer includes a first unit cell layer , a second unit cell layer, and an intermediate reflection film between the first unit cell layer and the second unit cell layer, the lower electrode of the first cell and the lower electrode of the second cell are covered by the lower electrode The separation groove is separated, and the photoelectric conversion layer on the lower electrode of the first battery is separated from each other to form a plurality of through holes for connecting the upper electrode of the second battery and the lower electrode of the first battery.

Description

Series-type integrated photoelectric module and manufacturing method thereof

technical field

The invention relates to a serial integrated photoelectric module and a manufacturing method thereof.

Background technique

At present, with the prediction that existing energy sources such as oil and coal will be exhausted, people are paying more and more attention to alternative energy sources to replace these existing energy sources. Among them, solar energy has attracted special attention because of its abundant resources and non-polluting environment.

Like diodes, photovoltaic modules that convert solar energy into electricity have a junction structure of p-type semiconductors and n-type semiconductors. When light hits the photoelectric module, there is an interaction between the light and the material that constitutes the semiconductor in the photoelectric module, generating electrons with (-) charges and holes with (+) charges, and the flow of charges generates current.

Photoelectric modules are divided into bulk type and thin film type according to the thickness of the semiconductor. Thin film photovoltaic modules include photoelectric conversion materials with a thickness of tens of μm to less than several μm.

At present, bulk silicon photoelectric components are widely used in the field of ground power. However, with the recent surge in demand for bulk silicon photovoltaic modules, there has been tight supply of raw materials and rising prices.

Therefore, there has recently been a demand for an integrated thin-film photovoltaic module that can be mass-produced at a low price while having high energy conversion efficiency. However, single-junction thin-film photovoltaic modules have limitations in their performance, so double-junction thin-film photovoltaic modules or triple-junction thin-film photovoltaic modules formed by laminating multiple unit cells have been developed in pursuit of highly stabilized efficiency (stabilized efficiency). Double-junction or triple-junction thin film photovoltaic modules are called tandem photovoltaic modules.

At the same time, for the purpose of reducing the ineffective area of thin-film photovoltaic modules and improving their efficiency, the industry is conducting research on the integration technology of photovoltaic modules.

Contents of the invention

The present invention has fully considered the problems existing in the prior art and the technical necessity, and its purpose is to provide a high-efficiency serial integrated photoelectric module and its manufacture that can minimize the leakage and ineffective areas of the photoelectric module and improve efficiency. method.

The technical issues to be solved in the present invention are not limited to the technical issues involved in the above, and other technical issues not involved in the present invention can be clearly understood by those skilled in the art from the contents described in the present invention.

A tandem integrated photoelectric module according to an embodiment of the present invention includes a first cell and a second cell formed by sequentially laminating a lower electrode, a photoelectric conversion layer, and an upper electrode on a substrate, and the photoelectric conversion layer includes a first unit cell layer , a second unit cell layer, and an intermediate reflection film between the first unit cell layer and the second unit cell layer, the lower electrode of the first cell and the lower electrode of the second cell are covered by the lower electrode The separation grooves are separated, and the photoelectric conversion layer on the lower electrode of the first battery is separated from each other to form a plurality of through holes for connecting the upper electrode of the second battery and the lower electrode of the first battery.

According to another embodiment of the present invention, the manufacturing method of the tandem integrated photoelectric module includes the steps of forming a lower electrode layer on the substrate; dividing the lower electrode layer into the lower electrode layer of the first cell and the lower electrode layer of the second cell The step of forming the lower electrode separation groove; the step of forming the photoelectric conversion layer including the first unit cell layer, the intermediate reflection film and the second unit cell layer on the lower electrode layers of the first battery and the second battery; penetrating through the A step of forming a plurality of through holes spaced apart from each other in the photoelectric conversion layer on the lower electrode layer of the second battery; a step of forming an upper electrode layer inside the through holes and on the photoelectric conversion layer; separating the upper electrode layer A part of the upper separation groove of the photoelectric conversion layer passes through the step above the lower electrode separation groove.

According to the present invention, the unit cells in the photoelectric module are connected in series through point contact, the invalid area in the photoelectric module is reduced, and the efficiency of the module can be improved. In addition, according to the present invention, the leakage current of the tandem photoelectric module can be reduced, and the efficiency can also be improved. In addition, according to the present invention, a tandem type integrated photoelectric module and a method for manufacturing the same can be provided.

Description of drawings

1 is a schematic diagram of a series-type integrated photovoltaic module including photovoltaic cells connected in series by point contacts according to an embodiment of the present invention;

Fig. 2 a and Fig. 2 b are the sectional views along a-a' line and b-b' line of Fig. 1;

3a to 3i show the manufacturing process of a series-type integrated photoelectric module according to an embodiment of the present invention;

Figure 4a and Figure 4b represent the intensity distribution of the laser beam and its associated pattern surface before and after passing through the homogenizer;

Figure 4c shows the cross-section of the pattern formed by the laser beam passing through the homogenizer;

5 is an enlarged view of the dotted quadrangular portion (A) of FIG. 1 according to an embodiment of the present invention;

6a and 6b are enlarged views of the dotted quadrangular portion (A) of FIG. 1 according to another embodiment of the present invention;

Fig. 7 a and Fig. 7 b are the sectional views along the c-c ' line of Fig. 6 a and the d-d ' line of Fig. 6 b;

8a to 8c are schematic diagrams of the shape of the second line surrounding the through hole according to the embodiment of the present invention.

Explanation of reference numbers

100: Substrate

200: lower electrode

220: Frontline

300: photoelectric conversion layer

310: first cell layer

320: Intermediate reflective film

330: second cell layer

400: upper electrode

420: second line

Detailed ways

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

However, the embodiment of the present invention can be changed into other various forms, and the scope of the present invention is not limited to the examples described below. For a clearer description, the image and size of the elements in the drawings can be enlarged. For the quotation marks in the drawings and the same constituent elements, even if they are marked on different drawings, they should be labeled with the same quotation marks as much as possible. When describing the present invention, if it is considered that specific descriptions related to known functions or configurations may obscure the gist of the present invention, detailed descriptions will be omitted.

1 is a schematic diagram of a photovoltaic module including photovoltaic cells connected in series by point contacts according to an embodiment of the present invention. In Fig. 1 and the following drawings, although the shapes of the lower electrode separation groove P1, the insulating groove P2, the through hole P3 and the upper separation groove P4 are shown on the upper surface of the photoelectric module, this is only for the convenience of illustration, and the upper part The shape may not be observed on the surface.

A photoelectric module according to an 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 or three unit cell layers laminated. Each of the laminated unit cell layers is a basic unit layer that performs photoelectric conversion.

An intermediate reflective film may be inserted between the laminated unit cell layers to enhance internal reflection and maximize light capture. For example, when the photoelectric conversion layer 300 includes two unit cell layers 310, 330, an intermediate reflection film 320 may be inserted between the two unit cell layers. The intermediate reflection film 320 is located between the two unit cell layers, so it can include a light-transmitting material. 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 cell layers, the photovoltaic cells UC1 and UC2 connected in series may be in the form of a plurality of unit cells 310 and 330 laminated. The open circuit voltage of the photoelectric cells UC1, UC2 is the sum of the open circuit voltages of the laminated unit cells 310, 330, and the short circuit current of the unit cells UC1, UC2 is the short circuit current of the laminated unit cells. min.

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

The through-holes P3 penetrating the photoelectric conversion layer 300 are formed not in a straight line but in a dot shape with a predetermined width, and are formed at intervals on one side of the lower electrode separation groove P1. Adjacent photovoltaic cells UC1 and UC2 are connected in series through the through hole P3. That is, the lower electrode 200 of the first battery UC1 and the upper electrode 400 of the second battery UC2 are connected through the dot-shaped through holes P3, so that the first battery UC1 and the second battery UC2 are connected in series.

These matters can be confirmed in the sectional view of FIG. 2a along the line a-a' of the photovoltaic module of FIG. 1 . As shown in FIG. 2 a , adjacent batteries UC1 and UC2 are connected in series through the portions formed by the mutually spaced through holes P3 .

The through-holes P3 exemplified in this specification are dot-shaped, but this is just an example, and if the plurality of through-holes P3 are formed separately from each other, it still belongs to the scope of the present invention. For example, the through hole P3 may be a segmented linear shape extending in one direction.

As mentioned above, the photoelectric module according to the embodiment of the present invention may include the lower electrode 200 , the photoelectric conversion layer 300 and the upper electrode 400 , and may also include a plurality of batteries UC1 and UC2 connected in series.

The separation groove P4 is formed through the photoelectric conversion layer 300 and the upper electrode 400 , thereby distinguishing the photoelectric cells UC1 and UC2 . The upper separation groove P4 is formed so as to overlap the path of the lower electrode separation groove P1 except that it surrounds the dot-shaped through-hole P3 in a predetermined shape. For example, the upper separation groove P4 may be formed along the second line 420 .

In order to facilitate the understanding of the present invention, a cross-sectional view along line b-b' of the photovoltaic module of FIG. 1 is shown in FIG. 2b. As shown in FIG. 1 , the upper separation groove P4 extends to the upper surface of the substrate 100 when the upper separation groove P4 passes over the lower electrode separation groove P1 . On the contrary, as shown in FIG. 2 b , the upper separation groove P4 only extends to the upper surface of the lower electrode 200 when the upper separation groove P4 does not pass through the portion above the lower electrode separation groove P1 . This is because, although the upper separation groove P4 is formed through the photoelectric conversion layer 300 and the upper electrode 400 , the lower electrode 200 has been removed by the lower electrode separation groove P1 at the portion where the lower electrode separation groove P1 is formed.

As described above, the first line 220 formed by the lower electrode separation groove P1 and the second line 420 formed by the upper separation groove P4 overlap except for a certain area, so the ineffective area of the photovoltaic module according to the embodiment of the present invention is reduced. In addition, the through-holes P3 for connecting the unit cells in the photovoltaic module in series are formed at predetermined distances in point contact, so that the ineffective area of the photovoltaic module can be reduced. Therefore, when the area remains the same, the area of the effective region increases, and a relative increase in the current value can be obtained.

In addition, according to the embodiment of the present invention, even if the intermediate reflective film 320 is a conductive material, electric leakage through the intermediate reflective film 320 can be prevented. This is because the insulating groove marked as P2 in FIG. 1 , FIG. 2 a and FIG. 2 b is formed on the intermediate reflection film 320 to insulate the through hole P3 from the intermediate reflection film 320 to achieve this purpose.

When viewing the photoelectric module from the side of the upper electrode 400 , the cross-sectional width of the insulating groove P2 is greater than that of the through hole P3 , and the through hole P3 passes through the interior of the insulating groove P2 . Therefore, the contact between the through hole P3 and the intermediate reflection film 320 can be prevented by the insulating groove P2. Accordingly, it is possible to prevent electric leakage caused by the substance of the upper electrode 400 contacting the intermediate reflection film 320 through the through hole P3.

The manufacturing process of a photovoltaic module including photovoltaic cells connected in series through point contacts according to an embodiment of the present invention will be described in detail below with reference to FIGS. 3 a to 3 i. Figures 3a to 3i represent three photovoltaic cells, but the photovoltaic module of the invention may comprise 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 photoelectric module according to the embodiment of the present invention performs photoelectric conversion through 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. 3 b , the 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 photoelectric module according to the embodiment of the present invention performs photoelectric conversion through light irradiated from the side of the upper electrode 400 , the lower electrode 200 may be an opaque electrode.

As shown in FIG. 3 c , the laser is irradiated in the air to the side of the lower electrode 200 or the side of the substrate 100 to scribe the lower electrode 200 . Thus, for example, the lower electrode separation groove P1 penetrating the lower electrode 200 is formed along the linear first line 220 . That is, since the lower electrodes 200 are separated by the lower electrode separation groove P1, a short circuit between the lower electrodes 200 can be prevented.

As shown in FIG. 3 d , a first unit cell layer 310 and an intermediate reflection film 320 are formed on the lower electrode 200 . At this time, the first unit cell layer 310 and the intermediate reflection film 320 may be formed inside the lower electrode separation groove P1.

The first unit cell layer 310 and the second unit cell layer 330 on the intermediate reflection film 320 to be formed later may include any substance that converts irradiated light energy into electrical energy. For example, the first and second unit cell layers 310, 330 may include photoelectric conversion materials that can form thin-film photovoltaic modules such as amorphous silicon, compound, organic, and dye-sensitized solar cells.

In the first unit cell layer and the second unit cell layer to be formed later, the intermediate reflection film 320 reflects a part of the light passing through the unit cell layer on which the light is first irradiated to the unit cell on which the light is first irradiated. layer, and part of it will pass through the remaining unit cell layer. As a result, the amount of light absorbed by the unit cell layer on which light is irradiated first increases, and the current generated in the unit cell layer increases.

As shown in FIG. 3 e , the insulating grooves P2 penetrating through the intermediate reflection film 320 and the first unit cell layer 310 may be formed separately from each other. According to an embodiment of the present invention, the insulating groove P2 may be formed by the intermediate reflective film 320 . The through hole P3 to be formed later can be prevented from being in contact with the intermediate reflection film 320 through such an insulating groove P2 .

As shown in FIG. 3 f , a second unit cell layer 330 is formed on the intermediate reflection film 320 . At this time, the insulating groove P2 may be filled with the substance of the second unit cell layer 330 .

At this time, the optical energy gap of the unit cell layer closer to light irradiation among the first and second unit cell layers may be larger than the optical energy gap of the remaining unit cell layers. For example, when light is irradiated through the substrate 100, the optical energy gap of the first unit cell layer is larger than the optical energy gap of the second unit cell layer. This is because short-wavelength light with high energy density has a short transmission distance, and a substance with a larger optical energy gap can absorb short-wavelength light more.

When the first unit cell layer and the second unit cell layer include an amorphous silicon-based photoelectric conversion material, according to other embodiments of the present invention, the insulating groove P2 may penetrate through other layers other than the intermediate reflection film And formed.

That is, the first unit cell layer and the second unit cell layer respectively include a p-type semiconductor layer, a pure semiconductor layer, and an n-type semiconductor layer laminated in the following order. According to an embodiment, the first and second unit cell layers may include an n-type semiconductor layer, a pure semiconductor layer, and a p-type semiconductor layer respectively sequentially laminated in the following order.

In this case, the insulating groove P2 may be formed through the p-type semiconductor layer in contact with the intermediate reflection film in addition to the intermediate reflection film 320 . When the p-type semiconductor layer, pure semiconductor layer and n-type semiconductor layer are sequentially laminated on the unit cell layer, the insulating groove P2 is formed in such a way that it can penetrate the intermediate reflection film 320 and the p-type semiconductor layer of the second unit cell layer . At this time, according to the embodiment, the insulation groove P2 may also penetrate through the first unit cell layer 310 .

When an n-type semiconductor layer, a pure semiconductor layer and a p-type semiconductor layer are sequentially laminated on the unit cell layer, the insulating groove P2 is formed in a manner that can penetrate the p-type semiconductor layer of the first unit cell layer and the intermediate reflection film 320 . At this time, according to the embodiment, the insulating groove P2 may also penetrate through the n-type semiconductor layer and the pure semiconductor layer of the first unit cell layer.

This is because generally the conductivity of the p-type semiconductor layer is high, and when the p-type semiconductor layer is in contact with the upper electrode 400 through the through hole P3, electric leakage may also occur. Therefore, as described above, when the insulating groove P2 is formed, the p-type semiconductor layer in contact with the intermediate reflection film 320 is penetrated at the same time, so that leakage can be prevented.

The photoelectric conversion layer 300 including the two unit cell layers 310, 330 and the intermediate reflection film 320 formed between the cell layers has been described above. However, according to an embodiment of the present invention, more than three unit cell layers may be included in the photoelectric conversion layer 300 . In addition, according to an embodiment of the present invention, the photoelectric conversion layer 300 may include more than two intermediate reflection films. At this time, the insulating groove is formed so as to penetrate through the two intermediate reflection films at the same time.

The unit cell layer of the photoelectric conversion layer 300 is usually formed in a vacuum state, and the laser patterning for forming the lower electrode separation groove P1, the insulation groove P2, the through hole P3 and the upper separation groove P4 is done in the atmosphere. Therefore, the photoelectric conversion layer 300 needs to be exposed to the atmosphere when performing laser scribing for the purpose of forming the through hole P3 described below in relation to FIG. 3g. In this way, when the photoelectric conversion layer 300 is exposed to the atmosphere, the photoelectric conversion layer 300 will be oxidized to cause deterioration of the photoelectric conversion layer 300 , which will eventually reduce the efficiency of the manufactured photoelectric module.

Therefore, when manufacturing the photoelectric module according to other embodiments of the present invention, it may also include forming the photoelectric conversion layer 300 in a vacuum state. A step of forming a transparent conductive film. In this way, the transparent conductive film is formed on the photoelectric conversion layer in a vacuum state, so that the photoelectric conversion layer 300 can be prevented from deteriorating due to exposure to the atmosphere. For example, since the photoelectric conversion layer 300 is formed on the transparent conductive film, it is prevented from being oxidized when laser scribing is performed in the atmosphere.

As mentioned above, the transparent conductive film not only has the protective function of the photoelectric conversion layer 300, but also can maximize the light trapping effect between the photoelectric conversion layer 300 and the upper electrode 400. ). That is, the transparent conductive film reflects the light that cannot be used for photoelectric conversion on the photoelectric conversion layer 300 and reuses it on the photoelectric conversion layer 300 , so the utilization efficiency of light can be improved. The transparent conductive film may include, for example, zinc oxide (ZnO) or indium tin oxide (ITO).

Although the through hole P3 only penetrates the photoelectric conversion layer 300 in the following description, according to an embodiment, the through hole P3 may be formed to penetrate the photoelectric conversion layer 300 and the transparent conductive film formed on the photoelectric conversion layer 300 . In addition, in the description, the upper separation groove P4 is also formed through the photoelectric conversion layer 300 and the upper electrode 400, but according to an embodiment, the upper separation groove P4 may be formed in such a way as to penetrate the photoelectric conversion layer 300, the transparent conductive film, and the upper electrode 400.

As shown in FIG. 3 g , the laser is irradiated in the atmosphere to the side of the substrate 100 or the side of the photoelectric conversion layer 300 to scribe the photoelectric conversion layer 300 . Thus, a plurality of mutually spaced through holes P3 penetrating the photoelectric conversion layer 300 are formed. At this time, the through hole P3 is not formed along a continuous straight line. A plurality of the through-holes P3 may be formed in a dot shape having a predetermined width and spaced apart from each other on one side of the lower electrode separation groove P1. The cells in the photovoltaic module are connected in series through the through-holes P3 formed in this way.

At this time, in order to allow the through hole P3 to be completely inserted into the insulating slot P2, the width of the section of the through hole P3 is smaller than the width of the section of the insulating slot P2. In this way, the through hole P3 can be insulated from the intermediate reflection film 320 and/or the p-type semiconductor layer connected to the intermediate reflection film 320 through the insulation groove P2.

As shown in FIG. 3 h , an upper electrode 400 covering the photoelectric conversion layer 300 and the through hole P3 is formed. The upper electrode 400 may include a conductive material that has excellent light reflection properties and can be used as an electrode. For example, the conductive material forming the upper electrode 400 may include aluminum (Al), silver (Ag), gold (Au), copper (cu), zinc (Zn), nickel (Ni), platinum (Pt), Palladium (Pd) or chromium (Cr), etc. The conductive substance forming the upper electrode 400 is filled into the through hole P3 to electrically connect the lower electrode 200 of the first battery and the upper electrode 400 of the other second battery among adjacent batteries.

In addition, when the photoelectric 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 that has good light reflection properties and can be used as an electrode.

As shown in FIG. 3i , laser light is irradiated in the atmosphere to scribe the photoelectric conversion layer 300 and the upper electrode 400 . Thus, the upper separation groove P4 penetrating through the photoelectric conversion layer 300 and the upper electrode 400 may be formed along the second line 420 . The path of the second line 420 is the same as that of the first line 220 formed by the lower electrode separation groove P2 except surrounding the dotted through hole P3. That is, except for the portion surrounding the through hole P3, the upper separation groove P4 passes over the lower electrode separation groove P1. The unit cells UC1, UC2 are defined by the upper separation groove P4.

According to other embodiments of the present invention, the process of forming the upper electrode in a vacuum state and forming the upper separation groove P4 by laser scribing in the atmosphere can be replaced by printing the upper electrode with a pattern in a non-vacuum state . For example, the upper electrodes patterned in the shape of the second lines 420 may be formed on the photoelectric conversion layer 300 by printing methods such as laser printing, inkjet printing, and screen printing in a non-vacuum state. In this way, the patterned upper electrode is formed in a non-vacuum atmosphere, thus saving manufacturing cost.

In the manufacturing process of the photoelectric module according to an embodiment of the present invention, the case where the lower electrode separation groove P1 is formed along the first line 220 and the upper separation groove P4 is formed along the second line 420 is illustrated. However, the lower electrode separation groove P1 may be formed along the second line 420 and the upper separation groove P4 may be formed along the first line 220 .

At this time, a ratio of a length of an overlapping portion of the upper separation groove and the lower electrode separation groove with respect to the length of the first line may be 0.70˜0.96. When the above-mentioned ratio is less than 0.70, the ineffective area increases, the effect of a sufficient current increase cannot be obtained, and the manufacturing time is prolonged. When the ratio is greater than 0.96, the moving path of electrons is prolonged, and impedance and Joule heating are increased, resulting in a decrease in the fill factor of the photovoltaic module.

In addition, according to FIG. 1 and the manufacturing process of the photovoltaic module according to an embodiment of the present invention described above, the width of the lower electrode separation groove P1 is greater than the width of the upper separation groove P4, but this is only an example. The width of the lower electrode separation groove P1 It may be less than or equal to the width of the upper separation groove P4.

During the manufacturing process of the photoelectric module according to the aforementioned embodiments of the present invention, at least one of the lower electrode separation groove P1 , the insulation groove P2 , the through hole P3 and the upper separation groove P4 may be formed by laser scribing. A laser processing machine (not shown) that performs such laser scribing may be provided with a homogenizer so that the intensity of the laser beam emitted by the laser oscillator is uniformly distributed in the irradiation area. This homogenizer can be composed of a combination of spherical lenses or an optical fiber cable utilizing total reflection characteristics.

As shown in Figure 4a and Figure 4b, when the laser beam with Gaussian intensity distribution emitted from the laser oscillator passes through the homogenizer, it will become a laser beam with uniform intensity distribution. In addition, when referring to Figures 4a and 4b, it can be found that the patterned surface produced by a laser beam with a Gaussian intensity distribution (Figure 4a) is comparable to the patterned surface produced by a laser beam with a uniform intensity distribution through a homogenizer (Figure 4b). Very irregular.

That is, when the intensity distribution of the laser beam is uniform, the pattern surface of the separation groove formed by laser beam irradiation becomes substantially uniform. Thus, the occurrence of burrs (burr) on the sidewalls of the lower electrode separation grooves, insulating grooves, through-holes and/or upper separation grooves P1, P2, P3, and P4 can be minimized, and integrated thin-film photovoltaics with improved efficiency can be produced. module. In addition, by using the laser beam passing through the homogenizer in this way, it is possible to prevent changes in the peripheral photoelectric conversion layer and electrode characteristics caused by increasing the laser energy to express the desired insulation characteristics.

In addition, the laser processing machine may include a mask formed with a prescribed pattern so as to selectively transmit the laser beam passing through the homogenizer. Therefore, only a laser beam area having a desired degree of uniform intensity distribution is used for the formation of separation grooves, insulating grooves, or through-holes.

Fig. 4c shows a cross-section of a separation trench, isolation trench or via pattern formed according to an embodiment of the present invention. In this case, the ratio of the step h of the pattern bottom surface to the pattern width W is preferably 5% to 10%. When the ratio of the step h to the pattern width W exceeds 10%, the edge of the pattern cannot be sufficiently removed, and leakage may occur. When the ratio of the step h to the pattern width W is less than 5%, too much laser energy is applied, and the surrounding photoelectric conversion layer and electrode characteristics may change.

In a photovoltaic module including photovoltaic cells connected in series through point contacts according to an embodiment of the present invention, it is very important to form an appropriate number of through-holes P3. If the number of the through-holes P3 is too large, the ineffective area will increase as in the linear laser scribing, and a sufficient effect of current rise cannot be obtained. In addition, since the upper separation groove P4 formed by laser scribing is formed so as to surround the through hole P3, the manufacturing time is prolonged. If the number of the through-holes P3 is too small, the path for electrons to move will be extended, resulting in increased impedance and joule heat, and a decrease in fill factor. Therefore, it is necessary to optimize the distance between the plurality of through holes P3 formed between two adjacent unit cells and the number of the through holes P3.

FIG. 5 is an enlarged view of a quadrangular portion (A) in dotted line in FIG. 1 . d represents the distance between two adjacent through-holes P3. x represents the distance between the first line 220 and the through hole P3. P3h represents a vertical foot falling from the through hole P3 to the first line 220 . J14 represents a branch point of the lower electrode separation groove P1 and the upper separation groove P4. r represents the distance between the P3h and J14.

As shown in FIG. 5 , the second line 420 overlaps the first line 220 except for the area surrounding the through hole P3 . That is, the second line 420 diverges from the first line 220 at a point J14 at a predetermined distance r from the vertical foot P3h to the first line 220, surrounds the through hole P3, and returns to the point J14 from the vertical foot P3h. Another location at a specified distance r from the first line 220 .

At this time, the through hole P3 may be located between the outermost point P4p of the second line 420 farthest from the first line 220 and the vertical foot P3h, and the vertical foot P3h is at a distance from the second line 420 The distance of the furthest peripheral point P4p of the first line 220 can be represented by 2x.

In the photoelectric module according to the embodiment of the present invention, the distance 2x may be 300 μm˜400 μm. Keeping the distance 2x within the above range not only prevents the short circuit between the insulating groove P2 and the through hole P3 between the lower electrode separation groove P1 and the upper separation groove P4, but also prevents unnecessary increase of the invalid area.

In the photoelectric module according to the embodiment of the present invention, the distance d between the through holes P3 is preferably 1 mm˜5 cm. At this time, the distance 2x relative to the distance d between the through holes P3 is the distance between the vertical foot P3h and the outermost point P4p of the second line 420 farthest from the first line 220 The ratio can be 6x10 ^-3 to 400x10 ^-3 . When the distance d is less than 1 mm, the ineffective area will increase, the current rising effect cannot be obtained sufficiently, and the manufacturing time will be prolonged. When the distance d is greater than 5 cm, the path for electrons to move to the lower electrode will increase, resulting in increased impedance and Joule heat, and a decrease in the fill factor of the photoelectric 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˜15 mm. When the width of the battery is less than 6mm, the ineffective area increases, the value of open circuit voltage (Voc) generated in each module becomes large, and the installation cost increases. When the battery width is greater than 15 mm, the impedance becomes larger and the efficiency decreases.

In order to perform edge isolation (edge isolation) in the module, what remains after removing semiconductors and conductors, and when the region performing photoelectric conversion is called an effective region, in the photoelectric module according to an embodiment of the present invention, relative to the effective region by laser scribing The ratio of the formed invalid area is about 0.015% to 2.7%.

In the photoelectric module according to the embodiment of the present invention, the shape of the second wire 420 surrounding the through hole P3 depends on the shortest distance of electrons from the through hole P3 to the second wire 420 . Only when the movement distance from the through hole P3 to the upper separation groove P4 surrounding the through hole is short can the generation of Joule heat be minimized. In addition, the shape should ensure that the distance from the through hole P3 is equal, so that the invalid area can be minimized. For example, the upper separation groove P4 surrounding the through hole P3 may have a partially circular shape. For example, the second line 420 may surround the through hole P3 in a partially circular shape.

As shown in FIG. 5 , the insulating groove P2 is penetrated by the through hole P3 and surrounded by the upper separation groove P4 . But this is just an example. As shown in FIG. 6a, when the insulating groove P2 is viewed from the upper electrode of the photoelectric module, the upper separation groove P4 can be formed in such a way that it traverses the insulating groove P2. Fig. 7a is a cross-sectional view along line c-c' of Fig. 6a. At this time, the width of the insulating groove P2 is large enough so that the through hole P3 and the upper separation groove P4 are formed in the insulating groove P2.

In order to insulate the through hole P3 from the conductive intermediate reflection film 320 and/or the p-type semiconductor layer in contact with the intermediate reflection film, when the through hole P3 is completely inserted into the insulating groove P2, the The width or shape of the insulating groove P2 can be varied in many ways. However, when the width of the insulating groove P2 becomes wider unnecessarily, the efficiency of the photoelectric module will decrease.

The insulating groove P2 may be polygonal, circular or elliptical. It is preferable to determine the shape of the insulating groove P2 so as to match the shape of the through hole P3, thereby maintaining proper insulation and preventing unnecessary reduction in current collection efficiency. For example, when the through hole P3 is circular or regular polygonal, the shape of the insulating groove P2 is also circular or regular polygonal, and its center coincides with the center of the through hole P3. Such a shape of the insulating groove P2 can be achieved by the laser processing machine including a mask formed with a prescribed pattern so that the laser beam passing through the homogenizer can be selectively transmitted.

Fig. 6b is an enlarged view of the quadrangular portion (A) shown in dotted line in Fig. 1 according to another embodiment of the present invention. In particular, another embodiment of the insulating groove P2 for preventing leakage due to possible contact between the material of the upper electrode 400 filled in the through hole P3 and the intermediate reflection film is shown. That is, the upper separation groove P4 and the lower electrode separation groove P1 are branched, and in a region surrounding the through hole P3, the insulation groove P2 is formed to form a closed loop with the upper separation groove P4. At this time, the through hole P3 may be located inside the closed loop formed by the insulation groove P2 and the upper separation groove P4. At this time, the insulating groove P2 may also be formed in a manner of forming a closed loop surrounding the through hole P3. That is, the insulating groove P2 may form a closed loop together with the upper separation groove P4, but the insulating groove P2 may alone form a closed loop surrounding the through hole P3.

The through hole P3 is in contact with the conductive intermediate reflection film 320 inside the closed loop and/or the p-type semiconductor layer in contact with the intermediate reflection film. However, through the insulating groove P2 and the upper separation groove P4 forming the closed loop, the p-type semiconductor layer in contact with the intermediate reflective film 320 and/or the intermediate reflective film is connected to the adjacent cell. The intermediate reflective film is insulated, so it can prevent leakage.

Fig. 7b is a cross-sectional view along line d-d' of Fig. 6b. At this time, it can be found that the intermediate reflective film 320 in contact with the through hole P3 is insulated from the intermediate reflective film of the adjacent battery by the insulating groove P2 and the upper separation groove P4.

In this specification, when the through hole P3 is located inside the closed loop, the situation that the through hole P3 overlaps with the insulating groove P2 is not excluded. That is, the insulating groove P2 may be larger than that shown in FIG. 6 b , and partially or completely overlap the through hole P3 . However, the through hole P3 is also insulated from the upper separation groove P4 at this time.

In addition, as long as the upper separation groove P4 and the insulating groove P2 can form a closed loop around the through hole P3, the insulating groove P2 can be of any length or shape. For example, the insulating groove P2 may be in a form in which two terminals in contact with the upper separating groove P4 are extended. The insulation groove P2 may also be formed along the first line 220 like the lower electrode separation groove P1.

According to other embodiments of the present invention, the upper separation groove P4 is formed along the linear first line 220, and when the lower electrode separation groove P1 is formed along the second line 420, the insulation groove P2 is formed in the same manner as the upper separation groove P3. The closed loop is formed to prevent leakage. At this time, the through hole P3 is located inside the closed loop formed by the insulating groove P2 and the upper separation groove P4.

8a to 8c show another example of the shape of the upper separation groove P4 surrounding the through hole P3 in the photoelectric module according to the embodiment of the present invention.

FIG. 8 a shows that the second line 420 diverges from the first line 220 at the bifurcation point J14 , and surrounds the shape of the through hole P3 along a part of the ellipse. At this time, the through hole P3 may be located between the vertical foot P3h and the outermost point P4p of the second line 420 . When the second line 420 surrounds the through hole P3 along a part of the ellipse or circle, the distance from the through hole P3 to the second line 420 is uniform, which can reduce the invalid area.

8b and 8c show that the second line 420 surrounds a part of the through hole P3 in a pentagonal or triangular shape. When the second line 420 surrounds the through hole P3 in this shape, the ineffective area can also be reduced, and the distance from the through hole P3 to the second line 420 is also uniform.

However, the illustrated shape is only an example, and in the photovoltaic module according to the embodiment of the present invention, the specific shape may be a part of a polygon including a pentagon or a triangle. In this case, all internal angles of the polygon are smaller than 180°, so that the invalid area can be effectively reduced. In addition, the polygon is preferably symmetrical with respect to a straight line connecting the vertical foot P3h, the through hole P3, and the outermost peripheral point P4p. In addition, all internal angles of the polygon are preferably larger than 90°, because when the internal angles of the polygon are acute angles, the laser beams are concentrated to the same vertex, forming excessive pattern formation or by heat generated by the photoelectric conversion layer and electrode layer may be damaged.

However, an angle θ formed by the first line 220 and the second line 420 at the bifurcation point J14 may have a value of 90°˜135°. For example, when the shape is a part of a circle or an ellipse, the angle formed by the tangent of the circle or ellipse on the bifurcation point J14 and the first line 220 is 90°˜135°. When the shape is the aforementioned polygon, the outer angle of the polygon at the bifurcation point J14 may be 90°-135°. When the angle θ is smaller than 90°, the distance between the second line 420 and the through hole P3 becomes longer, and the ineffective area cannot be effectively reduced. In addition, when the angle θ is greater than 135°, the width of the second line 420 surrounding the through hole P3 will become larger, and the effect of reducing the invalid area will be reduced.

In addition, depending on the shape surrounding the through-hole P3, the dot shape of the through-hole P3 may also have a circular, elliptical, or polygonal shape. The shape of the through hole P3 can be realized by including a mask formed with a predetermined pattern on the laser processing machine so that the laser beam passing through the homogenizer can be selectively transmitted. In this way, the shape of the through hole P3 is matched with the shape surrounding the through hole P3, which can shorten the distance for electrons to pass through the lower electrode from the through hole P3 to the second line 420 surrounding the through hole P3, and also make the distance uniform. .

The embodiments of the present invention have been described above with reference to the drawings, but those skilled in the art to which the present invention pertains can understand that other specific embodiments can be implemented without changing the technical idea or essential features. Therefore, the above-described embodiments of the present invention are illustrative in all aspects and not limited thereto.

Claims (27)

1. A tandem integrated photoelectric module, the module comprising, the first cell and the second cell which are respectively laminated to form a lower electrode, a photoelectric conversion layer and an upper electrode on the substrate, wherein, The photoelectric conversion layer includes a first unit cell layer, a second unit cell layer, and an intermediate reflection film between the first unit cell layer and the second unit cell layer, the lower electrode of the first battery and the lower electrode of the second battery are separated by a lower electrode separation groove, A plurality of through holes for connecting the upper electrode of the second battery and the lower electrode of the first battery are formed on the photoelectric conversion layer on the lower electrode of the first battery, separated from each other. 2. The tandem integrated photoelectric module according to claim 1, wherein the photoelectric conversion layer and the upper electrode of the first battery are separated from the photoelectric conversion layer and the upper electrode of the second battery by an upper separation groove , a part of the upper separation groove passes above the lower electrode separation groove. 3 . The tandem integrated photoelectric module according to claim 2 , wherein an insulating groove penetrating through the intermediate reflective film and inserted into the through hole is formed on the intermediate reflective film on the lower electrode of the first battery. 4 . 4. The series-type integrated photoelectric module according to claim 2, characterized in that, an insulating groove penetrating through the intermediate reflecting film is formed on the intermediate reflecting film on the lower electrode of the first battery, and the insulating groove is formed according to the intermediate reflecting film. The insulating groove and the upper separation groove form a closed loop, and the through hole is formed in such a way that it is located inside the closed loop. 5 . The series-type integrated photoelectric module according to claim 3 or 4 , wherein the through hole is filled with a conductive substance, and the insulating groove is filled with the second unit cell layer. 6 . 6. The tandem integrated photoelectric module according to claim 3 or 4, characterized in that, the first unit cell layer and the second unit cell layer comprise a P-type semiconductor layer, a pure semiconductor layer and a sequentially laminated An n-type semiconductor layer, the insulating groove penetrates through the intermediate reflection film and the p-type semiconductor layer in contact with the intermediate reflection film. 7. The series-type integrated photoelectric module according to claim 3 or 4, characterized in that one of the lower electrode separation groove and the upper separation groove has a straight shape. 8. The series-type integrated photoelectric module according to claim 7, characterized in that, relative to the length of the one separation groove, the ratio of the length of the part passing through the upper separation groove above the lower electrode separation groove 0.70 to 0.96. 9. The series-type integrated photoelectric module according to claim 7, characterized in that, the upper separation groove does not pass through the area above the lower electrode separation groove, and the lower electrode separation groove and the upper separation groove The other separation groove has a partially circular or elliptical shape. 10. The series-type integrated photoelectric module according to claim 9, characterized in that, at the bifurcation point where the other separation groove diverges from the straight line, the tangent line of the circle or ellipse and the straight line The formed angle is 90°-135°. 11. The series-type integrated photoelectric module according to claim 7, characterized in that, the upper separation groove does not pass through the area above the lower electrode separation groove, and the lower electrode separation groove and the upper separation groove The other separation groove has a partially polygonal shape. 12. The series-type integrated photoelectric module according to claim 11, characterized in that, at the bifurcation point where the other separation groove diverges from the straight line, the outer angle of the polygon is 90°-135°, All internal angles of the polygon are less than 180°. 13. The series-type integrated photoelectric module according to claim 7, wherein the through hole is located on the line falling on the straight line in the region where the upper separation groove does not pass through the lower electrode separation groove. The center between the vertical foot of the through hole and the outermost point of the other separation groove of the upper separation groove and the lower electrode separation groove. 14. The series-type integrated photoelectric module according to claim 3 or 4, wherein the widths of the first battery and the second battery are respectively 6mm-15mm. 15. The series-type integrated photoelectric module according to claim 3 or 4, characterized in that, the distance between two adjacent through-holes among the through-holes is 1 mm˜5 cm. 16. The series-type integrated photoelectric module according to claim 3 or 4, characterized in that, in the series-type integrated photoelectric module, relative to the active area, through the lower electrode separation groove, the insulating groove, the The ratio of the ineffective area formed by the through hole and the upper separation groove is 0.015%˜2.7°. 17. The series-type integrated photoelectric module according to claim 7, characterized in that, two adjacent through-holes in the through-holes are spaced apart by a specified distance, and those falling within the specified distance relative to the specified distance A distance ratio between the vertical foot of the through hole on the straight line and the outermost point of the other separation groove of the upper separation groove and the lower electrode separation groove is 6x10 ^-3 to 400x10 ^-3 . 18. The series-type integrated photoelectric module according to claim 3 or 4, wherein the cross-sectional shape of the through hole is circular, elliptical or polygonal. 19. The series-type integrated photoelectric module according to claim 3 or 4, wherein, relative to the width of at least one of the lower electrode separation groove, the insulation groove, the through hole and the upper separation groove The ratio of the step difference of the bottom surface is 5% to 10%. 20. A method of manufacturing a tandem integrated photoelectric module, the method comprising, a step of forming a lower electrode layer on the substrate; A step of forming a lower electrode separation groove for dividing the lower electrode layer into the lower electrode layer of the first battery and the lower electrode layer of the second battery; A step of forming a photoelectric conversion layer comprising a first unit cell layer, an intermediate reflection film, and a second unit cell layer on the lower electrode layers of the first cell and the second cell; a step of forming a plurality of spaced through holes penetrating through the photoelectric conversion layer on the lower electrode layer of the first battery; A step of forming an upper electrode layer inside the through hole and on the photoelectric conversion layer; A step of forming an upper separation groove for dividing the upper electrode layer and the photoelectric conversion layer so that a part thereof passes over the lower electrode separation groove. 21. The method for manufacturing a tandem integrated photoelectric module according to claim 20, wherein the step of forming the photoelectric conversion layer comprises: a step of forming the first unit cell layer; A step of forming the intermediate reflection film on the first unit cell layer; a step of forming an insulating groove for inserting the through hole through the intermediate reflection film on the lower electrode layer of the first battery; A step of forming the second unit cell layer inside the insulating groove and on the intermediate reflection film. 22. The method for manufacturing a tandem integrated photoelectric module according to claim 20, wherein the step of forming the photoelectric conversion layer comprises: a step of forming the first unit cell layer; A step of forming the intermediate reflection film on the first unit cell layer; An insulating groove penetrating through the intermediate reflecting film is formed on the intermediate reflecting film on the lower electrode of the first battery, and the insulating groove forms a closed loop according to the insulating groove and the upper separation groove, so that the through hole the step of forming in a manner located inside said closed loop; A step of forming the second unit cell layer inside the insulating groove and on the intermediate reflection film. 23. The manufacturing method of the tandem integrated photoelectric module according to claim 21 or 22, characterized in that, in the step of forming the insulating groove, a hole penetrating through the intermediate reflection film and the first unit cell layer is formed. Insulation slot. 24. The manufacturing method of the tandem integrated photoelectric module according to claim 21 or 22, characterized in that, the first unit cell layer and the second unit cell layer comprise sequentially laminated P-type semiconductor layers, pure a semiconductor layer and an n-type semiconductor layer, The step of forming the photoelectric conversion layer includes: Steps of forming the p-type semiconductor layer, pure semiconductor layer and n-type semiconductor layer of the first unit cell layer; A step of forming the intermediate reflection film on the first unit cell layer; A step of forming a P-type semiconductor layer of the second unit cell layer on the intermediate reflection film; The step of forming the insulating groove in such a way as to penetrate through the intermediate reflection film and the P-type semiconductor layer of the second unit cell layer; A step of forming the pure semiconductor layer and the n-type semiconductor layer of the second unit cell layer inside the insulating groove and on the p-type semiconductor layer of the second unit cell layer. 25. The manufacturing method of the tandem integrated photoelectric module according to claim 24, characterized in that, in the forming step of the insulating groove, a layer is formed through the first unit cell layer, the intermediate reflection film and the second The insulating groove of the P-type semiconductor layer of the unit cell layer. 26. The manufacturing method of the tandem integrated photoelectric module according to claim 21 or 22, characterized in that, the first unit cell layer and the second unit cell layer comprise sequentially laminated n-type semiconductor layers, pure semiconductor layer as well as the P-type semiconductor layer, The step of forming the photoelectric conversion layer includes: Steps of forming the n-type semiconductor layer, the pure semiconductor layer and the p-type semiconductor layer of the first unit cell layer; A step of forming the intermediate reflection film on the first unit cell layer; The step of forming the insulating groove in such a way as to penetrate the P-type semiconductor layer of the first unit cell layer and the intermediate reflection film; A step of forming the n-type semiconductor layer, the pure semiconductor layer and the p-type semiconductor layer of the second unit cell layer inside the insulating groove and on the intermediate reflection film. 27 . The manufacturing method of the tandem integrated photoelectric module according to claim 26 , wherein in the step of forming the insulating groove, an insulating groove penetrating through the first unit cell layer and the intermediate reflective film is formed.

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