SOLAR CELL AND MANUFACTURING METHOD THEREFOR

The present disclosure relates to a solar cell and a manufacturing method therefor. The solar cell includes: a base substrate; an electrode layer set on a surface of the base substrate, the electrode layer set including a first electrode and a second electrode, and the first electrode and the second electrode being electrically insulated from each other; a photoelectric layer disposed on a side of the electrode layer set facing away from the base substrate and electrically connected to the first electrode, the photoelectric layer being provided with a first via, and the position of the first via corresponding to the position of the second electrode; and a window layer disposed on a side of the photoelectric layer facing away from the base substrate and electrically connected to the second electrode through the first via.

CROSS REFERENCE TO RELATED APPLICATION

The application claims priority to Chinese patent application No. 201820893330.1, filed Jun. 8, 2018, which application is incorporated herein by reference in its entirety

FIELD

The present disclosure relates to the technical field of solar cells, and in particular, to a solar cell and a manufacturing method therefor.

BACKGROUND

In recent years, the increasingly prominent traditional energy issues have promoted the rapid development of new energy sources. Especially the clean energy represented by solar energy has received high-degree and extensive attention. Since the core material in the solar cell module is very sensitive to moisture, and exposure to the atmosphere tends to cause attenuation of power generation efficiency, the use of an effective packaging structure is important for ensuring the power generation efficiency and the service life of the solar cell module.

At present, the common packaging structure includes an externally-bonded packaging structure and an alternately stacked packaging structure of an organic thin film and an inorganic thin film. However, the packaging effect and the difficulty level of the packaging process are inevitably affected by the surface flatness of the solar cell. Therefore, ensuring that the surface of the solar cell is flattened is important for the packaging effect.

SUMMARY

To overcome the problems in the related art, embodiments of the present disclosure provide a solar cell. The technical solution is as follows.

According to a first aspect of the embodiments of the present disclosure, there is provided a solar cell, including:

a base substrate;

an electrode layer set disposed on a surface of the base substrate, the electrode layer set including a first electrode and a second electrode, and the first electrode and the second electrode being electrically insulated from each other;

a photoelectric layer disposed on a side of the electrode layer set facing away from the base substrate and electrically connected to the first electrode, the photoelectric layer being provided with a first via, and the position of the first via corresponding to the position of the second electrode; and

a window layer disposed on a side of the photoelectric layer facing away from the base substrate and electrically connected to the second electrode through the first via.

According to a second aspect of the embodiments of the present disclosure, there is provided a manufacturing method for a solar cell, including:

forming an electrode layer set on a base substrate, wherein the electrode layer set comprises a first electrode and a second electrode, and the first electrode and the second electrode are electrically insulated from each other;

forming a photoelectric layer on a side of the electrode layer set facing away from the base substrate and electrically connected to the first electrode, wherein the photoelectric layer is provided with a first via, and the position of the first via corresponds to the position of the second electrode; and

forming a window layer on a side of the photoelectric layer facing away from the base substrate and electrically connected to the second electrode through the first via.

The technical solution provided by the embodiment of the present disclosure may include the following beneficial effects: by disposing both the first electrode and the second electrode below the photoelectric layer, on the one hand, it can effectively avoid the shielding of the electrode from the photoelectric layer, so as to increase the aperture ratio of the solar cell, thereby improving its power generation efficiency. On the other hand, a recess structure corresponding to the second electrode may be formed on the surface of the window layer. Compared with a protrusion structure of the second electrode protruding beyond the surface of the window layer, the recess structure is more easily filled and leveled up, thereby facilitating planarization of the surface of the solar cell, so as to reduce the process difficulty of the thin film packaging and improve the effect of the thin film packaging.

DETAILED DESCRIPTION

Considering that the core material of the solar cell module is very sensitive to moisture, it is necessary to adopt a specific packaging structure to prevent the intrusion of moisture, thereby ensuring the power generation efficiency and the service life of the solar cell. At present, the common packaging structure includes an alternately stacked packaging structure of an organic thin film and an inorganic thin film. However, the packaging effect and the difficulty level of the packaging process are inevitably affected by the surface flatness of the solar cell.

FIG. 1exemplarily shows a schematic structural diagram of a solar cell in the related art. As can be seen fromFIG. 1, the solar cell10may include a base substrate100; a first electrode101, a photoelectric layer102, a window layer103, and a second electrode104which are sequentially disposed on the base substrate100; and an encapsulation layer105over the second electrode104. The first electrode101is a planar electrode and is laid on the surface of the base substrate100. The second electrode104is a strip electrode and is distributed on the surface of the window layer103.

Based on the structure, since the second electrode104is formed on the surface of the window layer103by a process such as lamination or screen printing, the thickness thereof is at least several micrometers or even tens of micrometers, and the thickness of the thin film packaging layer105is relatively small usually at only 2-3 micrometers or even thinner, the thickness of the second electrode104is too large compared to the encapsulation layer105, which will directly affect the process difficulty and packaging effect of the thin film packaging.

The technical solution provided by the embodiment of the present disclosure relates to a solar cell20. As shown inFIG. 2, the solar cell20includes:

a base substrate200, such as a flexible substrate or a glass substrate;

an electrode layer set201, disposed on the surface of the base substrate200, wherein the electrode layer set201includes a first electrode2011and a second electrode2012, and the first electrode2011and the second electrode2012are electrically insulated from each other;

a photoelectric layer202, disposed on a side of the electrode layer set201facing away from the base substrate200, and electrically connected to the first electrode2011, wherein the photoelectric layer202is provided with a first via2020, and the position of the first via2020corresponds to the position of the second electrode2012;

a window layer203, disposed on a side of the photoelectric layer202facing away from the base substrate200, and electrically connected to the second electrode2012through the first via2020.

The photoelectric layer202may include a photoelectric conversion semiconductor thin film such as a crystalline silicon semiconductor thin film or a CIGS (CuInGaSe) semiconductor thin film. The window layer203may be a transparent conductive thin film such as ITO (Indium Tin Oxide) thin film or AZO (Aluminum doped Zinc Oxid) thin film.

In the technical solution provided by the embodiment of the present disclosure, by disposing both the first electrode2011and the second electrode2012below the photoelectric layer202, it can effectively avoid the shielding of the electrode from the photoelectric layer202, so as to increase the aperture ratio of the solar cell20, thereby improving its power generation efficiency. On the other hand, a recess structure corresponding to the second electrode2012may be formed on the surface of the window layer203. Compared with a protrusion structure of the second electrode2012protruding beyond the surface of the window layer203, the recess structure is more easily filled and leveled up, thereby facilitating planarization of the surface of the solar cell20, so as to reduce the process difficulty of the thin film packaging and improve the effect of the thin film packaging.

In the present exemplary embodiment, the orthographic projection of the first electrode2011on the base substrate200and the orthographic projection of the second electrode2012on the base substrate200are mutually staggered, i.e., not overlapping with each other. The first electrode2011serves as a positive electrode of the solar cell20, and for example, may have a planar electrode structure having an opening. The second electrode2012serves as a negative electrode of the solar cell20, and for example, may have a strip electrode structure corresponding to the position of the opening.

Considering that the first electrode2011and the second electrode2012are both disposed on the side of the photoelectric layer202facing away from the window layer203, and the window layer203needs to be electrically connected to the second electrode2012through the first via2020in the photoelectric layer202, the window layer203may be electrically connected to the second electrode2012by forming a transparent conductive thin film constituting the window layer203or even by soldering, in order to ensure the reliability of the electrical connection between the window layer203and the second electrode2012. Forming the transparent conductive thin film means that the transparent conductive film itself can be directly formed on the surface of the second electrode2012through the first via2020in the process of forming the window layer203, to achieve an electrical connection therebetween. However, in a case where the distance between the window layer203and the second electrode2012(i.e., the depth of the via through which the window layer203is to pass) is large, the connection through the via may affect the reliability of the electrical connection therebetween. Therefore, soldering is further employed to ensure the reliability of the electrical connection therebetween.

In one embodiment, as shown inFIG. 3, the first electrode2011and the second electrode2012may be located in the same layer. For example, the first electrode2011and the second electrode2012may be formed on the same conductive layer and by the same photolithography process. The first electrode2011and the second electrode2012are separated by a predetermined interval to ensure an electrical insulation between the two electrodes. For example, as shown inFIG. 4, the predetermined interval between the first electrode2011and the second electrode2012may be formed by performing a scribe process (for example, providing a groove2013) at a preset position of the conductive layer. Alternatively, it is also possible to form the first electrode2011, and then form the second electrode2012at a predetermined interval from the first electrode2011. This is not specifically limited in this embodiment.

In this case, referring toFIG. 3, the solar cell20may include a base substrate200; an electrode layer set201disposed on the base substrate200and composed of a first electrode2011and a second electrode2012disposed in the same layer and spaced apart by a predetermined interval; a photoelectric layer202disposed on the electrode layer set201, electrically connected to the first electrode2011and having a first via2020corresponding to the second electrode2012; a window layer203disposed on the photoelectric layer202and electrically connected to the second electrode2012through the first via2020; and a packaging structure such as a planar layer204and a protective layer205disposed on the window layer203.

Referring toFIG. 4, the predetermined interval between the first electrode2011and the second electrode2012can be achieved by providing the groove2013, and the groove can be filled with insulating material or not filled with any material, as long as it can guarantee the electrical insulation between the first electrode2011and the second electrode2012and an electrical insulation between the first electrode2011and the window layer203. It should be noted that since the photoelectric layer202covers the surface of the first electrode2011during the process of forming the photoelectric layer202, it is only necessary to control the etching precision of the photoelectric layer202to ensure that the window layer203and the first electrode2011are not in contact with each other.

Based on this, in the present embodiment, by disposing the first electrode2011and the second electrode2012in the same layer and below the photoelectric layer202, on the one hand, the light receiving area of the solar cell20can be increased, thereby improving the power generation efficiency of the solar cell20. On the other hand, it can reduce the number of electrode deposition processes, which saves raw materials and simplifies the process. For example, if the first electrode2011and the second electrode2012are formed based on the same conductive layer, such as a metal molybdenum Mo conductive layer, and are formed through the same photolithography process, i.e., the first electrode2011and the second electrode2012are formed by performing a grooving process on the conductive layer, the thickness of the electrode layer set201can be relatively thin, the step difference can be relatively small, and the depth of the groove formed by the film layer located thereon can also be small. Therefore, the surface can be more easily filled and leveled up such that the surface flatness of the solar cell20can be improved to facilitate film encapsulation.

In addition, the first electrode2011and the second electrode2012may be made of the same material, and for example, they both are formed based on the same conductive layer. The first electrode2011and the second electrode2012each may be a metal electrode such as a metal molybdenum Mo electrode. Since the molybdenum Mo electrode is usually formed by a sputtering process, not only it can exhibit excellent film quality, but also can have low electric resistance, so that the thickness of the electrode can be significantly reduced.

In another embodiment, as shown inFIG. 5, the first electrode2011and the second electrode2012may be disposed in different layers. The first electrode2011is disposed in the upper side, i.e., away from the base substrate200, the second electrode2012is disposed on the lower side, i.e., proximate to the base substrate200, and an insulating layer2014is further provided between the first electrode2011and the second electrode2012. As shown inFIG. 6, a second via2015is disposed in the insulating layer2014, and a third via2016is disposed in the first electrode2011. The position of the second via2015and the position of the third via2016directly correspond to the position of the first via2020, to facilitate ensuring an electrical connection between the window layer203and the second electrode2012.

In this case, referring toFIG. 5, the solar cell20may include a base substrate200; a second electrode2012disposed on the base substrate200; an insulating layer2014disposed on the second electrode2012and having the second via2015; a first electrode2011disposed on the insulating layer2014and having a third via2016corresponding to the second via2015; a photoelectric layer202disposed on the first electrode2011and having a first via2020corresponding to the second via2015; a window layer203disposed on the photoelectric layer202and electrically connected to the second electrode2012through the first via2020, the second via2015and the third via2016; and a packaging structure disposed on the window layer203such as a planar layer204and a protective layer205.

Here, referring toFIG. 6, the first electrode2011, the second electrode2012, and the insulating layer2014therebetween together form the electrode layer set201. The first electrode2011may be correspondingly disposed at a first preset position, the second electrode2012may be correspondingly disposed at a second preset position, and the projections of the two preset positions on the base substrate200are mutually staggered, for example, not overlapping with each other. It should be noted that, in order to ensure an electrical insulation between the window layer203and the first electrode2011, in the embodiment, it may control the etching precision of the photoelectric layer202during the process of forming the photoelectric layer202, so that the photoelectric layer202can cover the first electrode2011. In addition, in the embodiment, the aperture of the third via2016can be controlled to be larger than the aperture of the first via2020. In this case, the photoelectric layer202can be coated on the surface of the first electrode2011, without being required to extend to the insulating layer2014.

Based on this, in the embodiment, the first electrode2011and the second electrode2012are disposed in different layers and disposed below the photoelectric layer202, so that the light-receiving area of the solar cell20can be increased, thereby improving the power generation efficiency of the solar cell20. For example, in the present embodiment, if the first electrode2011and the second electrode2012are formed based on different conductive layers, the second electrode2012such as a metal silver Ag electrode may be first formed on the base substrate200through one photolithography process, then an insulating layer2014having a second via2015may be deposited on the second electrode2012, next a first electrode2011having a third via2016, such as a metal molybdenum Mo electrode, is formed on the insulating layer2014through one photolithography process, thereby forming the desired electrode layer set201. It should be noted that the second via2015in the insulating layer2014and the third via2016in the first electrode2011can be realized by a laser etching process, in addition to the masking method and the photolithography process. The embodiment does not limit this. In this way, the film layer disposed above the electrode layer set201can form a groove structure at a position corresponding to the second electrode2012, and the groove structure is more easily filled with the surface than the protrusion structure. Therefore, the surface flatness of the solar cell20can be improved to facilitate film packaging.

Based on this embodiment, the first electrode2011and the second electrode2012may be made of the same material, i.e., both the first electrode2011and the second electrode2012are formed based on the same conductive film. The first electrode2011and the second electrode2012each may be a metal electrode such as a metal molybdenum Mo electrode. Since the molybdenum Mo electrode is usually formed by a sputtering process, not only it can exhibit excellent film quality, but also can have low electric resistance, so that the thickness of the electrode can be significantly reduced. Alternatively, the first electrode2011and the second electrode2012may also be made of different materials, i.e., the first electrode2011and the second electrode2012are formed based on different conductive films. For example, the first electrode2011is a metal molybdenum Mo electrode, and the second electrode2012is a metal aluminum Al electrode. This embodiment does not limit this.

In the present exemplary embodiment, referring toFIG. 3andFIG. 5, the solar cell20may further include an encapsulation layer on a side of the window layer203facing away from the base substrate200. The encapsulation layer may be used to protect the solar cell from moisture. erosion. The encapsulation layer can adopt a lamination structure of an organic film and an inorganic film, so as to improve the water vapor barrier capability of the encapsulation layer.

For example, the encapsulation layer may include a planar layer204on the side of the window layer203facing away from the base substrate200and a protective layer205on the side of the planar layer204facing away from the base substrate200. The planar layer204can be used to fill and level up the surface of the window layer203to facilitate the preparation of the subsequent film layer, and the planar layer204can be made of, for example, an organic resin material to form a thick and flexible organic planar layer. The protective layer205can be used to protect the surface of the solar cell, to reduce the damaged cracking, and for example, the protective layer205can be made of an inorganic film having a high hardness and a high water blocking ability such as a silicon nitride film or a diamond-like film.

The embodiments of the present disclosure relates to a manufacturing method for a solar cell. As shown inFIG. 7, the manufacturing method for a solar cell includes the following steps.

Step S2: forming a photoelectric layer202on a side of the electrode layer set201facing away from the base substrate200and electrically connected to the first electrode2011, wherein the photoelectric layer202is provided with a first via2020, and the position of the first via2020corresponds to the position of the second electrode2012.

Step S3: forming a window layer203on a side of the photoelectric layer202facing away from the base substrate200and electrically connected to the second electrode2012through the first via2020.

For example, the first electrode2011and the second electrode2012that are in the same layer and are separated by a predetermined interval are formed on the base substrate200.

For example, the second electrode2012is formed on the base substrate200; an insulating layer2014with a second via2015is formed on a side of the second electrode2012facing away from the base substrate200; and the first electrode2011with a third via2016is formed on a side of the insulating layer2014facing away from the base substrate200. Positions of the first via2020, the second via2015, and the third via2016are corresponding to one another.