CN218957742U - Back contact solar cell and photovoltaic module - Google Patents

Abstract

The utility model provides a back contact solar cell and a photovoltaic module, and relates to the technical field of photovoltaics. The back contact solar cell includes: the first surface side of the silicon substrate comprises a first semiconductor layer, a second semiconductor layer and a reserved block; the first surface includes: a first conductive region, a second conductive region, and an insulating isolation region between the first conductive region and the second conductive region; the first semiconductor layer is provided with at least a first part positioned on the first conductive area; the second semiconductor layer has at least a second portion located on the second conductive region; the first projection of the reserved block on the first surface falls in the insulating isolation region, the area of the first projection is smaller than that of the insulating isolation region, and gaps are reserved between the first projection and the first conductive region as well as between the first projection and the second conductive region. The reserved block is not subjected to laser etching basically, and the part covered by the reserved block is not subjected to laser etching basically, so that laser damage is reduced, open-circuit voltage and filling factor are improved, and the reliability of the battery is improved.

Description

A kind of back contact solar cell and photovoltaic module

technical field

The utility model relates to the field of photovoltaic technology, in particular to a back-contact solar cell and a photovoltaic module.

Background technique

Solar cells can directly convert light energy into electrical energy for production and life. They have the advantages of high efficiency, cleanliness, independence, and sustainability. They have important strategic significance for solving the energy crisis and ecological crisis, so they have broad application prospects.

Although there are various types of solar cells, such as those made of compound semiconductors or organic materials, solar cells made of crystalline silicon are currently the mainstream. According to its structure, solar cells are divided into: solar cells with double-sided electrode structure, in which the electrodes are respectively arranged on the main receiving surface of incident light and the backlight surface opposite to the main receiving surface of incident light. And it has a structure in which electrodes are provided only on the backlight surface. The advantage of a solar cell with a back electrode structure is that since there are no electrodes on the light-incident surface, the amount of incident sunlight can be increased, and the current loss caused by the shading of the electrodes on the light-incident surface can be reduced. However, the gap between the positive and negative grid lines on the back of the existing back-contact solar cell is prone to overcut during the manufacturing process, which reduces the product performance and yield of the back-contact solar cell.

Utility model content

The utility model provides a back-contact solar cell and a photovoltaic module, aiming at improving the cell performance and overall reliability of the existing back-contact solar cell.

According to a first aspect of the present invention, a back contact solar cell is provided, comprising: a silicon substrate, the silicon substrate includes a first surface, and the first surface side of the silicon substrate includes a first semiconductor layer, a second semiconductor layer, A reserved block; the first surface includes: a first conductive region, a second conductive region, and an insulating isolation region between the first conductive region and the second conductive region;

The first semiconductor layer has at least a first portion located on the first conductive region; the second semiconductor layer has at least a second portion located on the second conductive region;

A first projection of the reserved block on the first surface falls in the insulating isolation area, an area of the first projection is smaller than an area of the insulating isolation area, and the first projection and the insulating isolation area There are gaps between the first conductive region and the second conductive region.

In the embodiment of the present invention, the first projection of the reserved block on the first surface of the silicon substrate falls in the insulating isolation region, the area of the first projection is smaller than the area of the insulating isolation region, and the first projection and the second There is a gap between the first conductive region and the second conductive region, and the gap here can ensure a good insulation effect. The reserved block is basically not subjected to laser etching, and the part covered by the reserved block is basically not subjected to laser etching. The etching reduces laser damage, improves the open circuit voltage and fill factor of back contact solar cells, effectively reduces the quality problems caused by laser over-etching of cells in the process of mass production, and improves the reliability of cell products.

Optionally, the first semiconductor layer also has a third portion located on the insulating isolation region; the solar cell further includes a dielectric barrier layer located on the third portion; the second semiconductor layer also includes There is a fourth portion on the dielectric barrier layer; a second projection of the fourth portion on the first surface falls in the insulating isolation region, and the area of the second projection is smaller than the The area of the insulating isolation region; the reserved block includes at least part of the fourth portion.

Optionally, the solar cell further includes an insulating layer located on the insulating isolation region; the second semiconductor layer further has a fifth part located on the insulating layer, and a sixth part located on the first part. Part; the third projection of the fifth part on the first surface falls in the insulating isolation region, and the area of the third projection is smaller than the area of the insulating isolation region; the reserved block includes at least partially said fifth portion.

Optionally, the thickness of the second semiconductor layer is greater than or equal to the thickness of the first semiconductor layer; the direction of the thickness is parallel to the first direction.

Optionally, the reserved block is a continuous block structure, or the reserved block is a plurality of block structures distributed at intervals.

Optionally, the area of the first projection is smaller than the area of the gap between the first projection and the first conductive region, and the area of the gap between the first projection and the second conductive region The sum of the two areas.

Optionally, the first surface is a concave-convex surface; wherein, the insulating isolation region protrudes toward a direction away from the silicon substrate; the first conductive region and the second conductive region both face close to the silicon substrate The orientation of the base is concave.

Optionally, the shape of the first projection is a polygon, and each side of the polygon is an arc.

Optionally, the second semiconductor layer has at least a second portion located on the second conductive region; the first semiconductor layer includes a first layer stacked along a first direction away from the silicon substrate. an intrinsic semiconductor layer and a first conductive semiconductor layer, the second semiconductor layer includes a second intrinsic semiconductor layer and a second conductive semiconductor layer stacked along the first direction; the first conductive semiconductor layer and the The conductivity type of the second conductive semiconductor layer is opposite.

Optionally, the size of the polygon in each direction is 1 to 30 microns.

Optionally, the radius of the circle where the arc is located is 1 to 60 microns.

Optionally, the polygon is a triangle or a quadrangle.

Optionally, the insulating layer is a single-layer structure, or the insulating layer is a laminated structure.

Optionally, the solar cell further includes a transparent conductive layer on the first semiconductor layer and the second semiconductor layer, and the reserved block includes at least part of the transparent conductive layer on the insulating isolation region. layer.

The second aspect of the utility model provides a photovoltaic module, including: a plurality of back contact solar cells as described above.

The above-mentioned photovoltaic module has the same or similar beneficial effects as the above-mentioned back-contact solar cell, and in order to avoid repetition, details are not repeated here.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments of the utility model. Obviously, the accompanying drawings in the following description are only the illustrations of the utility model. For some embodiments, those of ordinary skill in the art can also obtain other drawings based on these drawings without paying creative efforts.

Fig. 1 shows a schematic structural view of a back contact solar cell in an embodiment of the present invention;

Figure 2 shows a schematic structural view of another back-contact solar cell in an embodiment of the present invention;

Fig. 3 shows a schematic structural diagram of a first projection in an embodiment of the present invention;

Fig. 4 shows a schematic structural diagram of another first projection in the embodiment of the present invention;

Fig. 5 shows a schematic diagram of a partial structure of the first back-contact solar cell in an embodiment of the present invention;

Fig. 6 shows a schematic diagram of a partial structure of a second back-contact solar cell in an embodiment of the present invention;

Fig. 7 shows a schematic diagram of a partial structure of a third back contact solar cell in an embodiment of the present invention;

Fig. 8 shows a schematic diagram of a partial structure of a fourth back-contact solar cell in an embodiment of the present invention;

Fig. 9 shows a schematic diagram of a partial structure of a fifth back-contact solar cell in an embodiment of the present invention;

Fig. 10 shows a schematic diagram of a partial structure of a sixth back contact solar cell in an embodiment of the present invention;

Fig. 11 shows a schematic diagram of a partial structure of a seventh back contact solar cell in an embodiment of the present invention;

FIG. 12 shows a schematic diagram of a partial structure of an eighth back-contact solar cell in an embodiment of the present invention.

Explanation of reference signs:

1-silicon substrate, 111-silicon substrate on the first conductive region, 112-silicon substrate on the insulating isolation region, 113-silicon substrate on the second conductive region, 2-dielectric layer, 3-barrier layer, 4-dielectric Electric barrier layer, 5-first intrinsic semiconductor layer, 6-first conductive semiconductor layer, 7-first electrode, 8-second electrode, 9-second intrinsic semiconductor layer, 10-second conductive semiconductor layer, 11-front passivation layer, 12-front anti-reflection layer, 13-reserved block, 14-transparent conductive layer.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. . Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

Fig. 1 shows a schematic structural diagram of a back-contact solar cell in an embodiment of the present invention. Fig. 2 shows a schematic structural diagram of another back-contact solar cell in an embodiment of the present invention.

Referring to Fig. 1 and Fig. 2, the back contact solar cell includes: a silicon substrate 1, which may be an N-type silicon substrate or a P-type silicon substrate. The silicon substrate 1 includes a first surface, which can be the surface on the side of the silicon substrate 1 in the back-contact solar cell where the electrode is arranged, that is, the backlight surface of the silicon substrate 1, and the light-facing surface of the silicon substrate 1 is the back-contact solar cell. The surface that mainly absorbs light, and the backlight surface is set opposite to the light-facing surface. The back contact solar cell further includes a first semiconductor layer, a second semiconductor layer, and a reserved block 13 all located on the first surface side of the silicon substrate 1 . The first surface includes: a first conductive region, a second conductive region and an insulating isolation region between the first conductive region and the second conductive region. In the back contact solar cell, the projection on the first surface is located in the first conductive region, which is mainly used for generating, separating and transporting the first type of carriers. In the back contact solar cell, the projection on the first surface is located in the structure of the second conductive region, which is mainly used for generating, separating and transporting the second type of carriers. The first type of carrier is different from the second type of carrier. The first type of carrier is one of electrons and holes, and the second type of carrier is one of electrons and holes. another. In the back-contact solar cell, the projection on the first surface is located in the insulating isolation region, which is mainly used to avoid short circuit and prevent leakage.

For example, in FIG. 1, the first surface of the silicon substrate 1 is the lower surface of the silicon substrate 1, and the first conductive region may be the left area of the first surface of the silicon substrate 1, that is, the part of the silicon substrate indicated by 111 in FIG. 1 The lower surface of 1, 111 is the silicon substrate on the first conductive region, and the second conductive region can be the right side region of the first surface of the silicon substrate 1, that is, the lower surface of the part of the silicon substrate 1 indicated by 113 in FIG. 1 , 113 is the silicon substrate on the second conductive region. Inside the isolation region is the middle-left region of the first surface of the silicon substrate 1 , that is, part of the lower surface of the silicon substrate 1 indicated by 112 in FIG. 1 , and 112 is the silicon substrate on the isolation region.

For another example, in Fig. 2, the first surface of the silicon substrate 1 is the upper surface of the silicon substrate 1, and the second conductive region may be the right side region of the first surface of the silicon substrate 1, that is, the part of silicon indicated by 113 in Fig. 2 The upper surface of the substrate 1, 113 is the silicon substrate on the second conductive region, the middle region of the first surface of the silicon substrate 1 in the insulating isolation region, and the left region, that is, the part of the silicon substrate 1 indicated by 112 in FIG. 2 112 is the silicon substrate on the insulating isolation region. The first conductive region may be the region sandwiched by two insulating isolation regions on the first surface of the silicon substrate 1, that is, the region on the left side of the middle of the first surface, that is, the part of the silicon substrate 1 indicated by 111 in FIG. The surface, 111 is the silicon substrate on the first conductive region.

It should be noted that the dotted lines running through the solar cell in Fig. 1 and Fig. 2 are only for distinguishing the first conductive region, the second conductive region, and the insulating isolation region, and do not mean that the solar cell is actually divided into several parts by the above dotted lines.

The first semiconductor layer has at least a first portion located on the first conductive region. The second semiconductor layer has at least a second portion located on the second conductive region. Optionally, the first semiconductor layer includes a first intrinsic semiconductor layer 5 and a first conductive semiconductor layer 6 stacked along the first direction L1 away from the silicon substrate, and the second semiconductor layer includes a first direction L1 away from the silicon substrate 1. The second intrinsic semiconductor layer 9 and the second conductive semiconductor layer 10 are stacked in the first direction L1, and the conductivity type or doping type of the first conductive semiconductor layer 6 and the second conductive semiconductor layer 10 are opposite. That is, one of the conductivity types of the first conductive semiconductor layer 6 and the second conductive semiconductor layer 10 is N-type doped, and the other is P-type doped.

The inventors found that in the prior art, the main reason for the slightly lower open-circuit voltage and fill factor of the back-contact solar cell is that in the prior art, the backlight side of the silicon substrate and the part where the projection falls in the insulating isolation area basically use laser However, laser etching will inevitably cause laser damage. Since the laser etching area is larger, the laser damage is more serious, and the more serious laser damage will remain in the back contact solar cell. , which in turn reduces the open circuit voltage and fill factor of back contact solar cells.

In view of the above problems, in the embodiment of the present invention, the first projection of the reserved block 13 on the first surface falls in the insulating isolation area, and the area of the first projection of the reserved block 13 on the first surface is smaller than the insulating isolation area area, and there is a gap between the first projection of the reserved block 13 on the first surface and the first conductive area and the second conductive area, the first projection of the reserved block 13 on the first surface and the first conductive area The gap between the regions, the first projection of the reserved block 13 on the first surface and the gap between the second conductive region are all conducive to improving the insulation effect, and at the same time, the reserved block 13 is basically not subjected to laser etching, and further The part covered by the reserved block 13 is basically not subjected to laser etching, which reduces laser damage, improves the open circuit voltage and fill factor of the back-contact solar cell, and effectively reduces the quality of the cell caused by laser over-etching in the process of mass production. Problems, improve the reliability of battery products.

There is no specific limitation on how much smaller the area of the first projection of the reserved block 13 on the first surface is than the area of the insulating isolation region. The size of the gap between the first projection of the reserved block 13 on the first surface and the first conductive region, and the size of the gap between the first projection of the reserved block 13 on the first surface and the second conductive region are also It is not specifically limited, and it is based on having a good insulating effect and minimizing laser damage.

Optionally, the back contact solar cell may be a back contact heterojunction solar cell, and the type of the back contact solar cell is not specifically limited.

Optionally, referring to FIG. 1 , the first semiconductor layer further has a third portion located on the insulating isolation region. The solar cell also includes a dielectric barrier layer 4 on the third portion, and the second semiconductor layer also has a fourth portion on the dielectric barrier layer 4 . That is, the projection of the dielectric barrier layer 4 on the first surface is the insulating isolation region, the area on the left side of the insulating isolation area on the first surface is the first conductive area, and the area on the right side of the insulating isolation area on the first surface is is the second conductive region. The second projection of the fourth part on the first surface falls in the insulating isolation region, and the area of the second projection is smaller than the area of the insulating isolation region. The main function of the dielectric barrier layer 4 is to provide insulation between the third part and the fourth part, and insulation between the third part and the second part. The reserved block 13 includes at least part of the fourth part, and by virtue of the back contact with the existing part on the solar cell, there is no need to separately set the layer where the reserved block 13 is located, and the cost can be appropriately reduced. Since the first projection of the reserved block 13 on the first surface needs to have a gap between the first conductive region and the second conductive region, therefore, in FIG. Partially there is a gap between the first projection of the first surface and both the first conductive area and the second conductive area.

Optionally, as shown in FIG. 2 , the solar cell further includes an insulating layer on the insulating isolation region. The insulating layer in FIG. 2 may be a laminated structure formed by the first passivation layer 2 and the dielectric insulating layer 3 . The main function of the insulating layer is to provide insulation between the first part and the second part. That is, the projections of the first passivation layer 2 and the dielectric insulating layer 3 on the first surface are the insulating isolation regions, one of which is located on both sides of the insulating isolation region is the first conductive region, and the other is the second conductive region. The second semiconductor layer also has a fifth portion on the insulating layer, and a sixth portion on the first portion. The third projection of the fifth part on the first surface falls in the insulating isolation region, and the area of the third projection is smaller than the area of the insulating isolation region, the reserved block 13 includes at least part of the fifth part, then by means of the back contact solar cell For the existing part above, there is no need to separately set the layer where the reserved block 13 is located, and the cost can be appropriately reduced. In FIG. 2 , there is a gap between the projection of the fifth part on the first surface and the first conductive region and the second conductive region. Therefore, in FIG. 2 , the reserved block 13 includes all the fifth part.

The method for preparing the solar cell shown in FIG. 2 may include: providing a silicon substrate 1 , and sequentially depositing a first passivation layer 2 and a dielectric insulating layer 3 on the first surface of the silicon substrate 1 . The first passivation layer 2 may include materials such as silicon oxide and hydrogenated amorphous silicon that can passivate surface dangling bonds, and the dielectric insulating layer 3 may include insulating materials such as silicon oxide and silicon nitride. Then a laser is used to form a first opening on the dielectric insulating layer 3 and the first passivation layer 2, so that the first surface is exposed. A first intrinsic semiconductor layer 5 and a first conductive semiconductor layer 6 are sequentially deposited on the exposed first surface and on the remaining dielectric insulating layer 3 . Then adopt laser to form the second opening on the first conductive semiconductor layer 6, the first intrinsic semiconductor layer 5, the dielectric insulating layer 3 and the first passivation layer 2, the first opening and the second opening have intervals, so that the first surface exposed. A second intrinsic semiconductor layer 9 and a second conductive semiconductor layer 10 are sequentially deposited on the exposed first surface and the remaining first conductive semiconductor layer 6 . A front passivation layer 11 and a front anti-reflection layer 12 are sequentially deposited on the second surface of the silicon substrate 1 opposite to the first surface, and a laser is used to combine the second intrinsic semiconductor layer 9 and the second conductive semiconductor layer 10 with the first The position corresponding to the opening forms a third opening, the third opening falls into the first opening, and the third opening is smaller than the first opening, so that the first conductive semiconductor layer 6 is exposed, and the remaining first conductive semiconductor layer 6 and the second conductive semiconductor layer 6 are exposed. A transparent conductive layer 14 is deposited on the semiconductor layer 10, and then a laser is used to form at least two fourth openings between the third opening and the second opening, and there are reserved blocks 13 between adjacent fourth openings. Then the first electrode 7 is formed at the position corresponding to the third opening on the transparent conductive layer 14 , and the second electrode 8 is formed at the position corresponding to the second opening. It should be noted that, the first opening, the second opening, the third opening, and the fourth opening here may also adopt methods such as wet etching, and the manner of forming the openings is not specifically limited.

Optionally, the thickness of the second semiconductor layer is greater than or equal to the thickness of the first semiconductor layer, and the direction of the thickness is parallel to the aforementioned first direction. That is to say, the sum of the thicknesses of the second intrinsic semiconductor layer 9 and the second conductive semiconductor layer 10 is greater than the sum of the thicknesses of the first conductive semiconductor layer 6 and the first intrinsic semiconductor layer 5, and is greater than the thickness of the first semiconductor layer 6. The thickness of the second semiconductor layer farther away from the silicon substrate 1 is larger, which can provide good protection for the first semiconductor layer and improve the effect of interface passivation and insulation isolation. How much the thickness of the second semiconductor layer is greater than the thickness of the first semiconductor layer is not specifically limited.

Optionally, as shown in FIG. 1 , the reserved block 13 is a continuous block structure. Alternatively, as shown in FIG. 2 , the reserved blocks 13 have a plurality of block structures distributed at intervals, and the reserved blocks 13 have various shapes. In Fig. 2, the reserved block 13 is a block structure distributed at three intervals.

Optionally, as shown in FIG. 1 and FIG. 2, the area of the first projection of the reserved block 13 on the first surface is smaller than the area of the gap between the first projection and the first conductive region, and the area of the gap between the first conductive region and the The sum of the area of the gap between the first projection and the second conductive region, the gap between the first projection and the first conductive region is larger, and the gap between the first projection and the second conductive region is also larger Larger, which can further improve the insulation effect.

Optionally, the first surface is a concave-convex surface, wherein the insulating isolation region protrudes toward the direction away from the silicon substrate 1, and the first conductive region and the second conductive region are concave toward the direction close to the silicon substrate 1, and then through the insulating isolation The region defines the first conductive region and the second conductive region in relatively independent concave regions, which enhances the insulation effect and can increase the fill factor and open circuit voltage.

For the silicon substrate 1 whose first surface is a concave-convex surface, the first conductive region and the second conductive region can be laser-scribed by using a laser first, and the insulating isolation region does not need laser scribing. After laser scribing, the first conductive region The first conductive region and the second conductive region will be in a loose state, and the first conductive region and the second conductive region are easier to etch than the insulating isolation region without laser scribing. Then soak the silicon substrate 1 with an alkaline solution, and the alkaline solution will etch away parts of the first conductive region and the second conductive region in a loose state, so as to obtain a concave-convex first surface.

Fig. 3 shows a schematic structural diagram of a first projection in an embodiment of the present invention. Fig. 4 shows a schematic structural diagram of another first projection in the embodiment of the present invention.

Optionally, as shown in FIG. 3 and FIG. 4, the shape of the first projection of the reserved block 13 on the first surface is a polygon, and each side of the polygon is an arc. Specifically, at present, laser-etched The shape of the laser beam is usually cylindrical, and the shape of the reserved block 13 is more suitable for the shape of the commonly used laser beam. The shape remaining after etching with the commonly used laser beam is the shape of the reserved block 13. Simple, mature, and easy to achieve mass production.

Optionally, referring to Figure 3 and Figure 4, the size of the polygon in all directions is 1 to 30 microns, the shape of the reserved block 13 can not only achieve a good insulation effect, but also can greatly improve the fill factor and open circuit voltage. For example, the dimensions of the polygon in various directions may be: 1 micron, 2 microns, 5 microns, 10 microns, 13 microns, 15 microns, 16 microns, 20 microns, 25 microns, 30 microns. The dimensions in various directions here may at least include: dimensions in two directions perpendicular to each other.

Optionally, referring to Fig. 3 and Fig. 4, the shape of the first projection of the reserved block 13 on the first surface is a polygon, each side of the polygon is an arc, and the radius of the circle where the arc is located is 1 to 60 Micron, the radius of the circle where the arc is located is more suitable for the shape of the commonly used laser beam, and the shape left after etching with the commonly used laser beam is the shape of the reserved block 13. The processing technology is simple and mature, and it is easy to realize the quantity Produce. For example, the radius of the circle where the arc is located can be: 1 micron, 2 microns, 5 microns, 10 microns, 13 microns, 15 microns, 16 microns, 20 microns, 25 microns, 30 microns, 33 microns, 40 microns, 46 microns Micron, 49 micron, 50 micron, 53 micron, 55 micron, 60 micron.

Optionally, referring to FIG. 3 and FIG. 4 , the shape of the first projection of the reserved block 13 on the first surface is a polygon, and the shape of the polygon is a triangle or a quadrangle. The shape of the reserved block 13 is more compatible with the shape of the commonly used laser beam, and the shape left after etching with the commonly used laser beam is the shape of the reserved block 13. The processing technology is simple and mature, and it is easy to realize mass production. For example, as shown in FIG. 3 , the shape of the first projection of the reserved block 13 on the first surface is a quadrilateral, and as shown in FIG. 4 , the shape of the first projection is a triangle.

Optionally, the shape of the insulating layer is a single-layer structure, or, referring to FIG. 2 , the insulating layer is a stacked structure. The shape of the insulating layer varies.

Optionally, as shown in FIG. 1 and FIG. 2 , the solar cell further includes a transparent conductive layer 14 on the first semiconductor layer and the second semiconductor layer, and the reserved block 13 includes at least part of the transparent conductive layer 14 . That is, the reserved block may include a portion that is located on the insulating isolation region and has a gap between its projection on the first surface and the first conductive region and the second conductive region.

The present application will be further explained below in conjunction with specific embodiments.

The silicon substrate 1 may be an N-type silicon substrate. First, the second surface of the silicon substrate 1 opposite to the first surface is chemically etched to form a textured structure, and the first surface is etched and polished with an alkaline or acidic solution.

Referring to FIG. 5 , after the surface of the silicon substrate 1 is cleaned, a first intrinsic semiconductor layer 5 and a first conductive semiconductor layer 6 are deposited on the polished first surface. During the deposition process: the temperature of the silicon substrate 1 is 200°C to 300°C, the deposition pressure is 4Torr (Torr) to 7Torr, the deposition power is 100W to 400W, and the first conductive semiconductor layer 6 is a P-type doped microcrystalline structure. A conductive semiconductor layer 6 is tested by Raman spectroscopy, and the characteristic peak of the microcrystalline structure is around 520 cm ⁻¹ . An intrinsic amorphous silicon layer is deposited on the second surface of the silicon substrate 1 as the front passivation layer 11 , and SiN _x as the front anti-reflection layer 12 .

Referring to FIG. 6 , a dielectric barrier layer 4 of 100 nm to 500 nm is deposited on the first conductive semiconductor layer 6 by low temperature CVD process, and the material of the dielectric barrier layer 4 is SiN _x .

Referring to FIG. 7, by laser, such as a green nanosecond laser, with an energy density of 100mj/ ^cm2 to 800mj/ ^cm2 etching technology, the dielectric barrier layer 4 and the first conductive semiconductor layer on the second conductive region are sequentially removed 6. The first intrinsic semiconductor layer 5, exposing the second conductive region.

Referring to FIG. 8, on the exposed second conductive region and on the remaining dielectric barrier layer 4, the second intrinsic semiconductor layer 9 and the second conductive semiconductor layer 10 are sequentially arranged, and the second intrinsic semiconductor layer 9 is an intrinsic The amorphous silicon layer, the second conductive semiconductor layer 10 is an N+ type doped amorphous silicon layer. Wherein, the total thickness of the second intrinsic semiconductor layer 9 and the second conductive semiconductor layer 10 is greater than the total thickness of the first conductive semiconductor layer 6 and the first intrinsic semiconductor layer 5, so as to ensure the good boundary cross section of the first conductive semiconductor layer 6 Passivation, specifically, the boundary area of the first conductive semiconductor layer 6 is completely covered by the second conductive semiconductor layer 10 to avoid side etching of the first conductive semiconductor layer 6 by subsequent wet processes and reduce battery edge recombination loss.

Referring to FIG. 9, the second intrinsic semiconductor layer 9 and the second conductive semiconductor layer 10 on the first conductive region are removed by etching using a laser, such as an ultraviolet nanosecond laser, with an energy density of 200mj/cm ² to 600mj/cm ² .

Referring to FIG. 10 , the dielectric barrier layer 4 on the first conductive region is removed by hydrofluoric acid solution, so that the first conductive semiconductor layer 6 on the first conductive region is exposed.

Referring to FIG. 11 , a transparent conductive layer 14 , such as a TCO conductive material, is deposited on the entire exposed first conductive semiconductor layer 6 and second conductive semiconductor layer 10 .

Referring to FIG. 12, by laser, such as ultraviolet nanosecond laser, energy density 500mj/cm ² to 1000mj/cm ² , or other etching, such as wet etching process, 3% to 10% HCl solution, complete the insulation isolation of the transparent conductive layer 14 , so that part of the second intrinsic semiconductor layer 9 , part of the second conductive semiconductor layer 10 , and part of the transparent conductive layer 14 on the dielectric barrier layer 4 serve as reserved blocks 13 .

With reference to Fig. 1 shown in can adopt screen printing method, the first electrode 7 is set on the position corresponding to the first conductive area on the transparent conductive layer 14, the second electrode 8 is set on the position corresponding to the second conductive area on the transparent conductive layer 14, Both the first electrode 7 and the second electrode 8 are metal electrodes.

The present application also provides a photovoltaic module, which includes any of the aforementioned back-contact solar cells, and has the same or similar beneficial effects as any of the aforementioned back-contact solar cells. In order to avoid repetition, it is not repeated here repeat.

It should be noted that, in this document, the term "comprising", "comprising" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article or apparatus comprising a set of elements includes not only those elements, It also includes other elements not expressly listed, or elements inherent in the process, method, article, or device. Without further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus comprising that element.

Embodiments of the present utility model have been described above in conjunction with the accompanying drawings, but the present utility model is not limited to the above-mentioned specific implementation, and the above-mentioned specific implementation is only illustrative, rather than restrictive. Under the enlightenment of the utility model, personnel can also make many forms without departing from the scope of protection of the purpose of the utility model and claims, and these all belong to the protection of the utility model.

Claims (12)

1. A back-contact solar cell, characterized in that it comprises: a silicon base, the silicon base includes a first surface, and the side of the first surface of the silicon base includes a first semiconductor layer, a second semiconductor layer, and a reserved block; The first surface includes: a first conductive region, a second conductive region, and an insulating isolation region between the first conductive region and the second conductive region; The first semiconductor layer has at least a first portion located on the first conductive region; the second semiconductor layer has at least a second portion located on the second conductive region; A first projection of the reserved block on the first surface falls in the insulating isolation area, an area of the first projection is smaller than an area of the insulating isolation area, and the first projection and the insulating isolation area There are gaps between the first conductive region and the second conductive region. 2. The back contact solar cell according to claim 1, wherein the first semiconductor layer also has a third portion located on the insulating isolation region; the solar cell also includes a third portion located on the third portion The dielectric barrier layer on the dielectric barrier layer; the second semiconductor layer also has a fourth portion located on the dielectric barrier layer; the second projection of the fourth portion on the first surface falls on the insulating isolation area, and the area of the second projection is smaller than the area of the insulating isolation area; the reserved block includes at least part of the fourth part. 3. The back contact solar cell according to claim 1, characterized in that, the solar cell further comprises an insulating layer positioned on the insulating isolation region; the second semiconductor layer also has an insulating layer positioned on the insulating layer. a fifth part, and a sixth part located on the first part; a third projection of the fifth part on the first surface falls in the insulating isolation region, and the area of the third projection is smaller than The area of the insulating isolation region; the reserved block includes at least part of the fifth portion. 4. The back contact solar cell according to claim 2 or 3, characterized in that, the thickness of the second semiconductor layer is greater than or equal to the thickness of the first semiconductor layer; the direction of the thickness and the first The directions are parallel; the first direction is along the direction away from the silicon substrate. 5. The back-contact solar cell according to any one of claims 1 to 3, wherein the reserved block is a continuous block structure, or the reserved block is a plurality of blocks distributed at intervals shape structure. 6. The back contact solar cell according to any one of claims 1 to 3, wherein the area of the first projection is smaller than the area of the gap between the first projection and the first conductive region , and the sum of the area of the gap between the first projection and the second conductive region. 7. The back contact solar cell according to any one of claims 1 to 3, wherein the first surface is a concave-convex surface; wherein the insulating isolation region protrudes toward a direction away from the silicon substrate; Both the first conductive region and the second conductive region are concave toward a direction close to the silicon substrate. 8. The back contact solar cell according to any one of claims 1 to 3, wherein the shape of the first projection is a polygon, and each side of the polygon is an arc. 9. The back-contact solar cell according to any one of claims 1 to 3, wherein the first semiconductor layer comprises first intrinsic semiconductor layers stacked along a first direction away from the silicon substrate layer and a first conductive semiconductor layer, the second semiconductor layer includes a second intrinsic semiconductor layer and a second conductive semiconductor layer stacked along the first direction; the first conductive semiconductor layer and the second The conductivity types of the conductive semiconductor layers are opposite. 10 . The back contact solar cell according to claim 3 , wherein the insulating layer is a single layer structure, or the insulating layer is a stacked layer structure. 11 . 11. The back contact solar cell according to any one of claims 1 to 3, wherein the solar cell further comprises a transparent conductive layer located on the first semiconductor layer and the second semiconductor layer, so The reserved block includes at least part of the transparent conductive layer on the insulating isolation region. 12. A photovoltaic module, characterized by comprising: several back-contact solar cells according to any one of claims 1-11.

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