KR20180095413A - Methods for making a solar cell - Google Patents

Abstract

The present invention relates to a method for manufacturing a solar cell. According to an embodiment of the present invention, the method for manufacturing a solar cell comprises: a scribing step of irradiating a laser along a scribe line onto a thin film constituting at least one layer of a solar cell; and a recovery step of simultaneously supplying heat and light to the thin film deteriorated by the irradiation of the laser. Therefore, the generation efficiency of the solar cell can be increased.

Description

[0001] METHOD FOR MANUFACTURING A SOLAR CELL [0002]

The present invention relates to a method of manufacturing a solar cell in which solar cells are divided into a plurality of solar cells and the solar cells are stacked on top of each other.

Recently, as energy resources such as oil and coal are expected to be depleted, interest in alternative energy to replace them is increasing, and solar cells that produce electric energy from solar energy are attracting attention.

Typical solar cells are made up of semiconductors that form p-n junctions of different conductivity types, such as p-type and n-type, and electrodes that are connected to semiconductor units of different conductivity types, respectively. This type of solar cell uses solar cell modules made by connecting several sheets to generate power and power.

One way to improve the efficiency of solar cell generation is to make a cut cell by dividing one solar cell made using standardized solar cell, 156 * 156 (mm) size wafer, and connecting these cut cells A solar cell module has been proposed.

Since the substrate used in the solar cell is a semiconductor, a scribing process of a semiconductor is adopted. The scribing process refers to a process of grooving the surface of a wafer with a diamond cutter or a laser to cut the wafer into a plurality of chips.

In relation to the present invention, when a laser beam is irradiated on a solar cell, there arises a problem that a portion irradiated with the laser beam is deteriorated. Here, deterioration is a phenomenon in which efficiency is reduced due to defects or the increase in the number of dangling bonds, and can easily be confirmed through the value of the fill factor (FF). The larger the deterioration of the solar cell, the lower the fill factor value

On the other hand, silicon thin films mainly used in solar cells can be divided into single crystal silicon, polycrystalline silicon and amorphous silicon depending on the crystal type of silicon. Of these, amorphous silicon is thermodynamically unstable, and its light absorption coefficient is 10 times higher than that of crystalline silicon (monocrystalline and polycrystalline silicon). When a laser is irradiated, it absorbs light energy more seriously than crystalline silicon there is a problem.

Although the above explanation describes the deterioration problem only for amorphous silicon, the polycrystalline silicon thin film and the metal oxide also have a problem that the degree of deterioration is greater than that of the single crystal silicon thin film and the film characteristics after the scribing process are greatly deteriorated.

The present invention has been made in view of such technical background, and is intended to recover a solar cell deteriorated by laser irradiation.

In an embodiment of the present invention, a scribing step of irradiating a laser along a scribe line above a thin film constituting a part of a solar cell, and a recovery step of supplying heat to the thin film irradiated with the laser, And a method for producing the same.

The thin film may include at least one of an amorphous silicon layer, a single crystal silicon layer, a polycrystalline silicon layer, and a metal oxide layer, and the thin film may form a rear electric field portion in the solar cell.

The solar cell may comprise a semiconductor substrate of monocrystalline silicon.

The manufacturing method of one embodiment may be performed in-line following the scribing step.

The recovering step may simultaneously supply light with the heat, and in the recovering step, the luminous intensity of the light may be 100 W / m ² to 30,000 W / m ^2, or preferably 100 W / m ² to 20,000 W / m ² .

In the recovery step, the wavelength of the light may be 300 nm to 1,000 nm, or preferably 400 nm to 800 nm.

In the recovery step, the process temperature may be 100 ° C to 300 ° C, or preferably 200 ° C to 300 ° C.

In the recovery step, the processing time may be 30 seconds to 1 hour, or preferably 1 minute to 30 minutes.

The manufacturing method of one embodiment includes dividing the solar cell into a plurality of cut cells between the scribing step and the recovery step, and applying a conductive adhesive to the cut cells, wherein the melting point of the conductive adhesive is It may be within the process temperature range of the recovery step.

According to an embodiment of the present invention, even when the solar cell receives a laser in the scribing process, the deteriorated solar cell can be recovered, thereby improving the power generation efficiency of the solar cell.

Fig. 1 shows a schematic plan view of a solar cell module made of cut cells.
Fig. 2 shows a sectional view of Fig.
3 is a view for explaining a method of transferring a mother cell.
4 shows a cross-sectional view taken along line AA 'of FIG.
Figure 5 illustrates a schematic monolayer structure of a solar cell.
6 is a flowchart illustrating a method of manufacturing a solar cell according to an embodiment of the present invention.
FIG. 7 schematically shows a facility in which a manufacturing method of a solar cell according to an embodiment of the present invention is implemented.
FIG. 8 shows a temperature change with time in the case of supplying only heat in the recovery step and in the case of supplying heat and light together.
9 is a flow chart illustrating a method in which a recovery step is performed in a string process of a cut cell.
10 schematically shows a facility in which a method of manufacturing a solar cell according to another embodiment of the present invention is implemented.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly explain the present invention in the drawings, parts not related to the description may be simplified or omitted. In addition, the various embodiments shown in the drawings are illustrative and may not be drawn to scale to facilitate illustration. The shape or structure can also be illustrated by simplicity.

FIG. 1 is a schematic plan view of a solar cell module made of cut cells, and FIG. 2 is a sectional view of FIG.

Referring to FIGS. 1 and 2, a solar cell module has a configuration in which a plurality of neighboring cut cells 10 are overlapped and a neighboring cut cell 10 in an overlapping portion is electrically connected.

The cut cell 10 may further comprise a pad 11 for electrical connection. The pads 11 are located corresponding to the overlapping portions of two adjacent cut cells 10, and are electrically connected to the electrodes of the cut cells 10.

The pad 11 is formed at the rear end of each cut cell and is electrically connected to the electrode disposed on the rear surface of the cut cell 10. [ A pad 11 is also formed at the front end of another adjacent cut cell 10 and is electrically connected to the electrode disposed on the front face of the cut cell 10.

These two cut cells are arranged so that the pads 11 overlap each other, and these two pads can be soldered by a conductive adhesive. Alternatively, an interconnect may be used to electrically connect the pad to the pad, and the electrode may be directly connected using the interconnector without using the pad 11, or may be directly connected by contacting the electrode It is possible.

Accordingly, the neighboring two cut cells are electrically connected by overlapping.

In one preferred form, the electrode and pad may be formed of a metallic material such as silver (Ag), and may be formed of the same metallic material or other metallic material. For example, the electrode and the pad may be formed of the same material through the same process, or may be formed of the same material, or may be formed of a conductive adhesive (or inter-connector) so that the pad portion can be well bonded to the conductive adhesive The solder material may include at least one of the solder materials.

3 and 4, the cut cell 10 has a size of 156 x 156 (mm) using a standardized solar cell (hereinafter, referred to as a mother cell) 1, for example, a square type, One can be divided into a plurality of cells. In the drawing, one solar cell is divided into four cells. In addition, although FIG. 1 illustrates that the mother cell 1 has a rectangular shape, the present invention is not limited thereto, and a solar cell using a pseudo square type wafer may also be included. The mother cell 1 used for the division includes a semiconductor substrate (for example, amorphous silicon, polycrystalline silicon, monocrystalline silicon or the like), an emitter which forms a pn junction with the semiconductor substrate, a rear electric field portion, a passivation film, Electrodes for collecting electric charges, and the like, and are omitted for convenience of explanation in the drawings. The parent cell 1 may be formed of various kinds of solar cells, such as a heterogeneous solar cell Various types of solar cells developed up to now, such as a solar cell made of a metal oxide, at least one of a double-side light-receiving solar cell, a rear-contact solar cell, an emitter, or a rear electric field can be used.

The mother cell 1 can be divided by irradiating a laser along the scribe lines L1, L2 and L3.

It is preferable that the laser is irradiated on the opposite surface of the light receiving surface of the mother cell 1 which receives light. When the laser is irradiated to the mother cell 1, the surface of the solar cell is melted by the laser, and the divided groove is formed while cooling. At this time, due to the high heat of the laser, heat energy is received around the formation of the divided grooves. In this process, the recombination site is increased due to the breakage of the bond between the stabilized silicon (Si). Therefore, when the laser beam is irradiated onto the solar cell, it is preferable that the laser beam is irradiated on the opposite surface of the light receiving surface of the mother cell 1.

Further, it is preferable that the laser LA is irradiated out of the region where the pn junction is formed. As is known, the solar cell 1 produces electricity by pn junction between the semiconductor substrate and the emitter. However, when the laser is irradiated to the region where the emitter is formed, the pn junction region is damaged by the laser, so that the power generation efficiency of the solar cell is inevitably lowered.

In consideration of these points, in the present invention, it is preferable that the laser is irradiated out of the region where the emitter is formed.

For example, in a solar cell having a general structure in which an emitter is formed on the front surface of a semiconductor substrate and electrodes are formed on the front and rear surfaces of the solar cell, the laser can be irradiated on the rear surface of the solar cell having no emitter have.

In the rear contact type solar cell in which both the emitter and the back surface electric field BSF are formed on the back surface of the semiconductor substrate, the laser is irradiated to the rear surface opposite to the light receiving surface, but can be irradiated so as to deviate from the region where the emitter is formed have.

As such, the laser irradiates the carrier beyond the pn junction where it is produced to prevent the generation efficiency of the solar cell from decreasing.

As the laser is irradiated along the scribing lines L1, L2 and L3, the dividing grooves SH are formed on the surface 13 irradiated with the laser among the solar cells 1 as the scribing lines L1, L2, L3). Here, the scribing lines L1, L2, and L3 are imaginary lines that indicate the direction in which the laser beam is irradiated to the solar cell 1 in order to divide the solar cell 1. The laser may be a pulse-type laser in order to reduce the damage by the laser in the preferred form. Since the pulse type laser is irradiated with the laser in synchronization with the pulse, the laser is intermittently irradiated without being continuously irradiated while the solar cell 1 is scanned. Therefore, the thermal energy applied to the solar cell Damage can be reduced. Preferably, the laser beam is irradiated several times in parallel to each of the scribing lines L1, L2 and L3 to form the dividing grooves SH, , The depth D1 of the dividing groove (SH), and the like. Accordingly, it is possible to irradiate the laser by reducing the intensity of the laser, thereby effectively reducing damage to the solar cell during the scribing process.

The depth D1 of the dividing groove SH is preferably 50% to 70% of the thickness T1 of the solar cell 1 in a preferred form. After the division groove (SH) is formed, the solar cell (1) receives a physical force and is divided into a plurality of cut cells. However, if the depth D1 of the dividing groove SH is smaller than 50%, the solar cell can not be divided along the dividing groove SH, and defects such as cracks can occur in the solar cell. When the depth D1 of the dividing groove SH is 70% or more, the thermal stress to be transmitted to the solar cell is increased and the efficiency of the solar cell can be lowered.

As shown, the cut cell 10 is made from a square solar cell 1, and thus has a substantially rectangular shape with a long side and a short side. In a preferred form, the cut cells 10 are arranged so that the long sides overlap, and the pads 11 of the cut cells 10 are located in the overlapping areas and are soldered to each other with the conductive adhesive interposed therebetween. At this time, the conductive adhesive is applied to the pads 11 before the cut cells 10 are superimposed on one another after the mother cells 1 are divided into cut cells 10, or they are applied to the mother cells before they are divided into cut cells It is possible.

Figure 5 illustrates a schematic monolayer structure of a solar cell illustrating the present invention. 5, various thin films 103 and 105 are formed on a semiconductor substrate 101 as a base by a semiconductor process.

For example, a passivation film, an antireflection film, a backside electrical part, an emitter, and the like may be formed as a thin film on a semiconductor substrate 101 formed of silicon by a thin film process such as PECVD, LPCVD, or CVD.

The material forming the thin films 103 and 105 includes a metal oxide semiconductor thin film (for example, indium-gallium-zinc oxide (IGZO)), a silicon thin film doped with impurities, an intrinsic silicon thin film, The silicon thin film may be any one of amorphous silicon, single crystal silicon, and polycrystalline silicon depending on the crystallinity.

The silicon thin film 103 doped with the impurity may be an emitter forming the pn junction with the semiconductor substrate 101 or a rear electric field portion doped with impurities of the same conductivity type as that of the doped impurity in the semiconductor substrate 103 at a high concentration. In addition, the metal oxide layer may also be used as an emitter or a back electric field portion, such as a doped silicon thin film 103.

The intrinsic silicon thin film 105 may constitute at least one of a passivation film and an antireflection film.

The thickness of such thin films formed on either or both sides of the semiconductor substrate 101 is approximately 2 to 3 (um), while the thickness of the semiconductor substrate is approximately 180 (um).

The thin films 103 and 105 are easily deteriorated by the irradiation of the laser, whereas the degree of deterioration is relatively small due to the thickness of the semiconductor substrate 101. Particularly in the case of monocrystalline silicon, And the deterioration is small.

On the other hand, when the thin films 103 and 105 are amorphous silicon layers, not only is thermodynamically unstable but also has a higher light absorption coefficient than that of a stable single crystal silicon, deterioration easily occurs and the value of the fill factor (FF) is drastically lowered after the scribing process There is a number.

Silicon thin films can be classified into amorphous silicon, single crystal silicon, and polycrystalline silicon depending on the crystallinity. The laser irradiation causes the deterioration of the amorphous silicon most severely, while the single crystal silicon has the least deterioration. The metal oxide is the same as the amorphous silicon Deterioration occurs in the range.

In order to solve such a problem, the manufacturing method of the present invention includes a recovery step of recovering a deteriorated solar cell.

Hereinafter, a method of manufacturing a solar cell according to an embodiment of the present invention will be described. 6 is a flowchart illustrating a method of manufacturing a solar cell according to an embodiment of the present invention.

A manufacturing method of an embodiment of the present invention includes a scribing step (S11) of irradiating a laser along a scribe line above a thin film constituting a part of a solar cell, a step of supplying a heat to the thin film irradiated with the laser , And a recovery step S13. In the recovery step, light can be supplied simultaneously with heat. If light is supplied simultaneously with heat, a higher heat can be used than when only heat is supplied, so that the recovery step can be performed more effectively.

In the scribing step S11, the laser is irradiated onto the amorphous silicon layer, the single crystal silicon layer, the polycrystalline silicon layer or the metal oxide layer amorphous silicon layer, the single crystal silicon layer, the polycrystalline silicon layer or the metal oxide layer The film is irradiated onto the thin film including at least one of the films.

Thus, in order to recover the thin film deteriorated by the laser irradiation, the recovery step (S13) is performed following the scribing step (S11).

In the process of making cut cells, deterioration occurs in the process of irradiating the solar cell with the laser and in dividing the solar cell into the cut cell. Therefore, the recovery step S13 may be performed immediately after the scribing step, or may be a recovery process in which the cut cells are connected to each other after the solar cells are divided into cut cells along the dividing grooves formed in the scribing process, Step may be performed. Generally, the division of a solar cell refers to a process in which a dividing groove is formed on the surface of a solar cell by advancing to a scribing step and then mechanically rolled along the dividing groove by a roller to divide into a plurality of cut cells.

Considering that the flow and cost of a continuously in-line facility and the problem of deterioration of the actual solar cell largely occur during the scribing step of irradiating the laser, ) Step is preferably carried out. For reference, the present inventors have experimented with aberrations in order to investigate the degree of deterioration in stages, and the deterioration that occurs after laser irradiation is about 2 to 2.5 times larger than the deterioration that occurs after dividing into cut cells.

FIG. 7 shows a schematic view of a facility implemented in an in-line form in which the scribing step and the recovery step are carried out continuously. The manufacturing method of the present invention is not necessarily implemented in such a facility, and the equipment of Fig. 7 is only a drawing for illustration.

The rollers 321 and 323 rotate in the direction of the arrow and the belt 330 moves in the clockwise direction. The solar cell 1 is sequentially supplied to the laser device 410 and the recovery device 510 in accordance with the movement of the belt 330 while being positioned on the belt 330.

The laser device 410 is configured to include a laser 411 that irradiates a laser to the solar cell 1 in accordance with a scribed line in accordance with a programmed procedure, And light source units 511 and 513 and heat source unit 521 for supplying heat and light to the solar cell 1 at the same time, respectively.

In a preferred form, the light source units 511 and 513 and the heat source unit 521 are arranged to face each other with the solar cell 1 therebetween, and the operations of the light source units 511 and 513 and the heat source unit 521 Can be controlled individually.

In such a facility, the solar cell 1 is moved in the direction of the arrow by the rotation of the rollers 321 and 323 and sequentially supplied to the laser device 411 and the recovery device 510.

The laser device 410 irradiates the solar cell 1 with a laser in accordance with the programmed conditions. The laser 411 may be a YAG laser in a preferred form, and the oscillation conditions may be variously adjusted depending on the crystal structure of the solar cell 1, the thickness, the depth of the dividing groove, and the like. In addition, the laser may be any of those well-known in the art, such as CO ₂ laser, which can form a depth of 50% to 70% of the depth of the dividing groove with respect to the thickness of the solar cell as described above.

The laser 411 irradiates a laser beam onto the surface of the transferred solar cell 1, preferably the opposite surface (hereinafter referred to as the irradiation surface) of the light-receiving surface to form a dividing groove. When irradiating the solar cell 1 with a laser, the surface of the solar cell is melted by the laser, and a dividing groove is formed while cooling. At this time, due to the high heat of the laser, heat energy is applied to the vicinity of the formation of the dividing grooves. In this process, recrystallization is performed and defects such as dangling bonds are increased, so that the laser LA is preferably irradiated on the irradiation surface.

Therefore, in a preferred form, the solar cell 1 is transported so that the irradiation surface faces the laser LA.

The photovoltaic cell 1 irradiated with the laser, that is, the photovoltaic cell 1 in which deterioration (or defect) occurs is then supplied directly to the recovery device 510 in accordance with the movement of the belt 330.

In the present invention, the recovery step may be performed in such a manner that heat, heat and light are supplied to the solar cell 1 to recover the deteriorated solar cell. It may be more effective to supply light and heat at the same time than to supply only solar cells with heat.

According to experiments conducted by the present inventors, there has been a problem that when the amorphous silicon layer is supplied only with heat, the amorphous silicon layer deteriorates at a specific temperature of about 200 ° C or higher. Therefore, in the case of supplying only the heat, the recovery step can be performed only at a temperature lower than 200 ° C, whereas when the light is supplied simultaneously with the heat, the temperature at which the amorphous silicon layer deteriorates is increased. Therefore, it is preferable that the recovery step is performed by simultaneously supplying heat and light to the solar cell, rather than only supplying heat to the solar cell.

  When a laser beam is irradiated on the solar cell, a dividing groove is formed on the surface of the solar cell by the laser, and the passivation film formed on the surface of the solar cell is removed. Therefore, the recombination site increases around the split groove. In the recovery step, the heat and light supplied to the solar cell can improve the mobility of hydrogen included in the silicon thin film, thereby increasing the diffusion rate of hydrogen and improving the deterioration. A large amount of hydrogen is contained in the silicon thin film. In the case of defects generated by laser irradiation, for example, hydrogen migrates to a part where the bond between silicon is broken and stabilizes these bonds, or hydrogen diffuses rapidly to these interfaces It can be easily diffused. Thus, the amount of hydrogen located inside the amorphous semiconductor layer can be greatly reduced, and defects at the interface can be reduced.

Further, when a laser beam is irradiated on a solar cell, the laser irradiated periphery is heated to a high temperature (about 700 ° C) by a laser. Then, the bond between the stabilized bonds is absorbed by thermal energy, and the leakage current is increased. In the recovery phase, the heat and light supplied to the solar cell increase the diffusion rate of hydrogen as described above, It is possible to reduce the deterioration of the solar cell by the laser irradiation.

In the recovery step, the light provided to the solar cell 1 may have a luminous intensity of 100 W / m ² to 30,000 W / m ² . If the luminous intensity is less than 100 W / m ² , the effect of the recovery step may not be sufficient. It may be difficult to realize light by a current light source having a luminous intensity exceeding 30,000 W / m < ² >. As an example, the light provided to the solar cell 1 in the recovery phase may have a luminous intensity of 100 W / m ² to 20,000 W / m ² . According to this, the effect of the recovery step can be effectively improved.

As an example, the light provided to the solar cell 1 in the recovery step may have a wavelength of 300 nm to 1,000 nm. Light in the infrared region having a wavelength exceeding 1,000 nm can heat the solar cell 1 to a controllable level or higher. Thus, in this embodiment, only the light having a wavelength range that is related to the recovery of the solar cell 1 can be used to maximize the effect of the recovery step of the solar cell 1. In one example, the light provided to the solar cell 1 may have a wavelength of 400 nm to 800 nm. When the deterioration of the silicon thin film (for example, an amorphous silicon film or the polycrystalline silicon film) and the metal oxide film is prevented by using the light having a wavelength directly related to the photoelectric conversion of the solar cell 1, Can be maximized.

On the other hand, the light provided to the solar cell 1 in the recovery step may have a wavelength of 400 nm or less, specifically 300 to 400 nm. In this case, the luminous intensity may be 100 W / m ² to 5,000 W / m ² . In addition, the light provided to the solar cell 1 in the recovery step may have a wavelength of more than 400 nm and less than 1,000 nm, wherein the luminous intensity may be 100 W / m ² to 30,000 W / m ² . This is because they have different energies according to the wavelength of light provided to the solar cell 1, and thus the light intensity can also be changed corresponding to the wavelength of the light.

 Therefore, since a light source having a wavelength band of 400 nm or less has a high energy, a wavelength band exceeding 400 nm can be provided with a lower luminous intensity as compared with a light source, thereby maximizing the effect. As described above, the light provided to the solar cell 1 in the recovery step improves the mobility of hydrogen at the wavelengths and luminances in the above-mentioned range, thereby preventing the silicon thin film from being deteriorated by the light. In the present embodiment, the recovery step may be performed at room temperature or in a state where heat is supplied. Particularly, when heat is supplied together with light in the recovery step, the effectively deteriorated silicon thin film can be effectively recovered.

As an example, the process temperature of the recovery step may be from room temperature to 300 캜 (for example, from 15 to 300 캜). Here, the process temperature may mean the temperature of the solar cell 1 in which the recovery step is performed. If the process temperature is lower than room temperature, the effect of the recovery step may be deteriorated, and a separate device should be used to lower the process temperature. If the process temperature exceeds 300 캜, the silicon thin film may be deteriorated during the process of performing the recovery step before the effect of the recovery step is realized. As an example, the recovery step may be at a process temperature of 100 ° C to 300 ° C. This is because the effect of the recovery step can be further improved when the process temperature is 100 ° C or more.

At this time, in this embodiment, the process temperature of the recovery step can be set to 200 to 300 캜. As described above, according to the present embodiment, deterioration of the silicon thin film in the solar cell 1 can be prevented by the light applied in the recovery step, and thermal stability can be secured at a temperature of 200 ° C or higher.

Thus, the recovery step can be performed even at a relatively high process temperature of 200 to 300 캜. In this embodiment, the process temperature which is the temperature of the solar cell 1 in the recovery step by light can be effectively improved. That is, when light is used together with heat, the temperature of the solar cell 1 can be improved by light. Thus, the amount of heat supplied to the solar cell 1 through the heat source can be reduced, thereby reducing manufacturing costs. In addition, it may be difficult to finely control the temperature of the solar cell 1 due to the heat applied by the heat source. By irradiating the solar cell 1 with light in a state where the temperature is within the approximate temperature range, The temperature of the battery 1 can be finely controlled in a desired range and stably maintained.

In the present embodiment, the recovery step may be performed by injecting the solar cell 1 into the recovery device 510 having the above-described process temperature and providing light without a separate preheating process. This is because the process temperature is not high, and therefore there is little possibility that problems such as degradation of the characteristics of the solar cell 1 due to abrupt temperature change occur at the process temperature. Accordingly, the preheating process and equipment for the same can be eliminated, thereby improving productivity.

The process time of the recovery step may be from 30 seconds to 1 hour. If the process time is less than 30 seconds, the effect of the recovery step may not be sufficient. If the process time exceeds 1 hour, the process time may be long and the productivity may be lowered. As an example, the process time of the recovery step may be from 1 minute to 30 minutes. According to this, high productivity can be maintained while stably implementing the effect of the recovery step.

On the other hand, the light source units 511 and 513 serve to provide light having a desired light intensity to the solar cell 1. Since the light intensity required for recovering 100 W / m ² to 30,000 W / m ² light source (511, 513) may provide the light having a light intensity of 100W / m ² to 30,000 W / m ^2.

At this time, various methods of adjusting the luminous intensities of the light source units 511 and 513 may be applied in order to provide the light of the brightness required for the recovery step. That is, the number, type, and output of the light sources (not shown) constituting the light source units 511 and 513 can be adjusted or the distance between the light source and the solar cell 1 can be changed.

In this embodiment, the light source units 511 and 513 may be formed of a plasma lighting system (PLS) that provides light by plasma light emission. In a plasma lighting system, a specific gas is filled in a bulb, and an electromagnetic wave or an incident beam such as a microwave generated by a magnetron is applied to highly ionize the gas inside the bulb (i.e., generate a plasma) Light is emitted from the plasma. The wavelength of the light emitted by the plasma lighting system may be between 300 and 1200 nm.

The plasma lighting system does not use electrodes, filaments, and mercury, which are components of conventional lighting systems, and is environmentally friendly and has a semi-permanent life. And the luminous flux retention rate is very excellent. Therefore, even when used for a long time on the basis of a super light flux, the amount of light change is small. It is resistant to heat and is excellent in thermal stability, so that it is not a problem to use it in the same space as the heat source portion 521, and can emit light of sufficient brightness. For reference, other light sources such as light emitting diodes and the like are vulnerable to heat, so that they are difficult to use together with the heat source portion 521 and emit only light of a low level of luminous intensity. In addition, the plasma lighting system can emit substantially uniform continuous light over the entire wavelength of the visible light region, thereby providing light similar to sunlight. In this case, an In-Br compound formed by combining indium (In) and bromine (Br) with a gas filling the inside of the bulb of the plasma lighting system may be used. Thus, it is possible to have a spectrum more similar to that of sunlight than in the case of using a conventional sulfur gas. Providing light having a spectrum similar to that of the sunlight allows the recovery step to be performed under conditions similar to the sunlight, thereby effectively preventing deterioration or the like, which may be caused by the sunlight, in advance in the recovery step.

In this embodiment, the use of the plasma lighting system as the light source unit 520 is exemplified. Thus, the light of the desired light intensity can be stably provided to the solar cell 1. However, the present invention is not limited thereto, and a xenon lamp, a halogen lamp, a laser, a light emitting diode (LED), or the like may be used as the light source unit.

Meanwhile, a UV lamp that emits ultraviolet light may be used as the light source unit, and the UV lamp may emit light of a wavelength of 300 to 400 nm. However, it is not limited thereto, and the UV lamp may emit extreme ultraviolet rays of less than 300 nm.

As described above, in the recovery step, the solar cell is heated to the target temperature by the heat source unit 521, or the light source unit 511 and 513 simultaneously light the solar cell while the heat source unit 521 heats the solar cell. Can be supplied. When the solar cell is heated only by the heat source unit 521, the process temperature may be 100 占 폚 to 300 占 폚, preferably 200 占 폚 to 300 占 폚.

In this embodiment, the light source units 511 and 513 and the heat source unit 521 provide light and heat to the solar cell 1 at positions separated from each other. In this state, the light source units 511 and 513 and the heat source unit 521 provide light and heat to the solar cell 1 to minimize the influence of the light source units 511 and 513 and the heat source unit 521 on each other have.

The light source units 511 and 513 may be located on one side of the solar cell 1 and the heat source unit 521 may be on the other side of the solar cell 1 in the main region 220. [ Thus, the light and heat generated by the light source units 511 and 513 and the heat source unit 521 can be effectively transmitted to the solar cell 1 while minimizing interference between the solar cells.

Meanwhile, FIG. 8 shows temperature changes with time in the case of supplying only heat and in the case of supplying heat and light together in the recovery step.

As illustrated in FIG. 8, the process temperature can be easily raised higher when heat and light are supplied together, as compared with a case where only heat is supplied.

Thus, the amount of heat supplied to the solar cell 1 through the heat source can be reduced, thereby reducing manufacturing costs. In addition, it may be difficult to finely control the temperature of the solar cell 1 due to the heat applied by the heat source. By irradiating the solar cell 1 with light in a state where the temperature is within the approximate temperature range, The temperature of the battery 1 can be finely controlled in a desired range and stably maintained.

The description of the recovery step has been made by taking a silicon thin film (an amorphous silicon film or a polycrystalline silicon film) as an example, but the above description is not limited to the silicon thin film. According to the results of experiments conducted by the present inventors, the silicon thin film and the metal oxide layer showed the same or similar recovery results under the same conditions. Therefore, the recovery step S13 described above can be applied to the metal oxide layer in the same or similar manner.

Table 1 below shows the experimental results for examining the effect of the manufacturing method according to one embodiment of the present invention.

In this experiment, a p + doped amorphous silicon layer was formed on a monocrystalline silicon substrate and a passivation layer of the entire substrate was used. A picosecond (ps) IR laser with an output power of 8 to 9 (W) was used. The laser was irradiated once to the amorphous silicon layer to form a groove having a depth of about 50% of the total thickness of the solar cell.

In order to investigate the degree of deterioration of the solar cell, the output voltage of the solar cell was measured before (A), after the irradiation (B), after dividing the solar cell (C) (mV) were measured. The total of three substrates were used to measure the change of the output voltage in each case.

In this experiment, the recovery of the solar cell was performed by supplying heat and light of 210 ° C to the solar cell at the same time for 10 minutes. At this time, the light having a luminance of 1,800 W / m ² and a wavelength of 530 nm was used.

As a result, the output voltage (A) of the experimental example 1 was 757 (mV), but the output voltage (B) after the laser irradiation was reduced by about 11 (mV) to 746 (mV). The decrease in the output voltage before and after the laser irradiation is caused by the deterioration of the amorphous silicon layer. After cutting the solar cell, (C) showed a power reduction of about 2 (mV) compared to (B), but after the recovery step (D) B), the output voltage was again increased to 746 (mV).

According to Experimental Example 2, the output voltage gradually decreased from 753 (mV) to 743 (mV) in (A), 743 (mV) in (B), and 744 ), Respectively.

In Experiment 3, the output voltage was gradually decreased to 751 (mV), 741 (mV), and 740 (mV) in (A), (B) and (C), respectively. (mV) of the output voltage.

As described above, according to the embodiment of the present invention, after the laser is irradiated to the solar cell and the recovery step is performed, the output deceleration width is about 15%, the experimental example 2 is about 18%, the experimental example 3 is about 17% Of the total.

Before laser irradiation (A) After laser irradiation (B) After division (C) After recovery (D) Experimental Example 1 757 (mV) 746 (mV) 744 (mV) 746 (mV) Experimental Example 2 753 (mV) 743 (mV) 742 (mV) 744 (mV) Experimental Example 3 751 (mV) 741 (mV) 740 (mV) 743 (mV)

Meanwhile, although the scribing step S11 and the recovery step S13 are performed in an in-line form in the above-described embodiment, the present invention is not limited thereto.

Alternatively, in another embodiment of the present invention, the scribing step S11 and the recovery step S13 may be separately performed. In a preferred form, the recovery step S13 may be performed simultaneously with the recovery step S11 in the bonding process of connecting the cuts 10 to each other.

This will be described with reference to FIG. FIG. 9 is a flowchart for explaining an embodiment in which a recovery step S13 is included in the process of stringing the cut cell 10, and FIG. 10 schematically shows a facility used therefor.

Referring to these drawings, the manufacturing method shown in Fig. 9 is carried out by using two independent facilities SU1 and SU2. The first equipment SU1 includes a laser device 410 and a dividing device 610. [ The laser apparatus 410 comprises a laser 411 for irradiating the laser to the mother cell 1 in accordance with the scribed line in accordance with the programmed procedure and the divider 610 comprises a laser- 1) is divided into a plurality of cut cells (10) by mechanical impact. The specific configuration of such a facility has already been variously implemented in various forms in the technical field, and a detailed description thereof will be omitted here.

The second facility SU2 includes a dispenser 710 for applying a conductive adhesive onto a pad (not shown) formed for each cut cell 10 and the laid-up cut cells to cure the conductive adhesive, And a recovery device 510 for simultaneously performing a recovery process for recovering the generated deterioration. The recovery device 510 includes the light source units 511 and 513 and the heat source unit 521 as described above, and the configuration and operation of the recovery device 510 are the same as those described above, and thus a detailed description thereof will be omitted.

In step S101, the belt 330 on which the mother cell 1 is placed is positioned below the laser device 410 by the rotation of the rollers 321 and 323. [ The laser device 410 is formed on the surface of the mother cell 1 in the dividing groove as described above by irradiating the mother cell 1 in accordance with the programmed procedure.

In step S102, the mother cell 1 in which the dividing grooves are formed is divided along the dividing grooves by the dividing device 610 to form a plurality of cut cells 10. [ For example, the divided cell 610 may be divided into a plurality of cut cells 10 by impacting one side of the cut cell 10 while supporting the cut cell 10 with a jig (not shown).

Steps S103 and S104 are carried out by the second facility SU2, and a transfer means such as a robot can be used for the movement between the equipments.

In step S103, the dispenser device 710 discharges the conductive adhesive CA on the cut cell 10, more precisely on the pad (not shown), in accordance with the programmed information. As a result, a conductive adhesive is applied onto the pads of all the cut cells 10 passing through the dispenser device 710. In one example, a wide variety of conductive adhesives (CA) may be used in general. For example, solder paste, solid state solder, or the like may be used. The conductive adhesive may be any of those having a melting point within the temperature range applied to the solar cell 1 in the above-described recovery process. As described above, since the solar cell is heated at a temperature of 100 ° C to 300 ° C or a temperature of 200 ° C to 300 ° C during the recovery process, any conductive adhesive that hardens in this temperature range may be used.

In step S104, other cut cells 10 are laid up on the cut cells 10 to which the conductive adhesive CA is applied, and are supplied to the heating device 510. Although not shown in the drawings, the second cut cell 10 is selectively placed over the first cut cell 10 coated with the conductive adhesive CA by means of a robot or the like so as to be in contact with the pad portion of the first cut cell. Can be modified. Here, the second cut cell 10 may be coated with a conductive adhesive agent or may not be coated with the conductive adhesive agent. The conductive adhesive may be applied to the plurality of cut cells 10 and then laid up thereon and supplied to the heating device 510 to perform a recovery step S13, or a conductive adhesive may be applied to one cut cell 10, It is also possible to carry out the recovery step S13 for each cut cell as if the cells were laid up and fed to the heating device 510 to perform the recovery step S13.

Heat and light supplied while passing through the heating device 510 are used in a range as described in the above-described recovery step S13. Accordingly, the cut cells deteriorated in the laser irradiation process can be recovered at the same time in the process of hardening the conductive adhesive.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, Of the right.

Claims (16)

A scribing step of irradiating a laser along a scribe line above a thin film constituting a part of the solar cell; And,
A recovery step of supplying heat to the thin film to which the laser is irradiated;
Wherein the method comprises the steps of: The method according to claim 1,
Wherein the thin film comprises at least one of an amorphous silicon layer, a single crystal silicon layer, a polycrystalline silicon layer, and a metal oxide layer. 3. The method of claim 2,
Wherein the thin film forms a rear electric field portion in the solar cell. The method according to claim 1,
Wherein the solar cell comprises a semiconductor substrate made of monocrystalline silicon. The method according to claim 1,
Wherein the recovery step is performed in-line immediately after the scribing step. The method according to claim 1,
Wherein the recovery step simultaneously supplies light with the heat. The method according to claim 6,
Wherein the light intensity of the light in the recovery step is 100 W / m ² to 30,000 W / m ² . 8. The method of claim 7,
Wherein the light intensity of the light in the recovery step is 100 W / m ² to 20,000 W / m ² . The method according to claim 6,
And the wavelength of the light is 300 nm to 1,000 nm in the recovery step. 10. The method of claim 9,
And the wavelength of the light in the recovery step is 400 nm to 800 nm. The method according to claim 6,
And the process temperature in the recovery step is 100 ° C to 300 ° C. 12. The method of claim 11,
And the process temperature in the recovery step is 200 ° C to 300 ° C. The method according to claim 6,
And the process time in the recovery step is 30 seconds to 1 hour. 14. The method of claim 13,
And the process time in the recovery step is 1 to 30 minutes. 7. The method according to claim 1 or 6,
Between the scribing step and the recovery step,
Dividing the solar cell into a plurality of cut cells; And,
Applying a conductive adhesive to the cut cells; Lt; / RTI >
Wherein the melting point of the conductive adhesive is within the process temperature range of the recovery step. 16. The method of claim 15,
Wherein the conductive adhesive has a melting point of 100 占 폚 to 300 占 폚.

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