A solar cell and a photovoltaic module

Abstract

The present invention discloses a solar cell and a photovoltaic module. The solar cell comprises a silicon substrate, a first transmission layer and a second transmission layer. The first surface of the silicon substrate is provided with the first transmission layer and the second transmission layer respectively, and the first transmission layer and the second transmission layer are alternately arranged. The first transmission layer is provided with an etched area, and the plane where the etched area is located is lower than or flush with the plane of the first transmission layer away from the silicon substrate; and / or the second transmission layer is provided with an etched area, and the plane where the etched area is located is lower than or flush with the plane of the second transmission layer away from the silicon substrate. The etched area has particles, and the particles can increase the back reflection of the front transmitted light, thereby improving the light absorption efficiency of the solar cell.

Description

Technical Field

[0001] The present invention relates to the field of solar photovoltaic technology, and in particular to a solar cell and a photovoltaic module. Background Art

[0002] Solar cells are devices that directly convert light energy into electrical energy. If the light-entering surface of the cell is blocked, the cell's absorption of sunlight will be reduced, so the short-circuit current loss of the cell is large. This is also a problem currently faced by almost all silicon-based solar cells. Therefore, the research on solar cells without electrodes on the light-entering surface is particularly important. Based on this, back-contact cells can solve this problem because their electrodes are set on the back of the cell, which can minimize the short-circuit current loss caused by the upper surface. In this cell structure, there are no grid lines on the front side, and the entire area is used to absorb sunlight. The back of the cell is provided with an electron transport layer and a hole transport layer.

[0003] However, the solar cells in the prior art still have the defect that the back side reflection efficiency of the front side transmitted light is low, resulting in poor light absorption efficiency. Summary of the invention

[0004] In view of this, the present invention proposes a solar cell and a photovoltaic module, aiming to partially or completely solve the technical problems of the existing solar cells having low back side reflection efficiency and poor light absorption efficiency of the front side transmitted light.

[0005] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0006] In a first aspect, an embodiment of the present invention provides a solar cell, comprising a silicon substrate, a first transmission layer and a second transmission layer, wherein the first transmission layer and the second transmission layer are respectively disposed on the first surface of the silicon substrate, and the first transmission layer and the second transmission layer are alternately arranged; the first transmission layer is provided with an etched region, and a plane where the etched region is located is lower than or flush with a plane where the first transmission layer is away from the silicon substrate; and / or the second transmission layer is provided with an etched region, and a plane where the etched region is located is lower than or flush with a plane where the second transmission layer is away from the silicon substrate; the etched region has particulate matter.

[0007] Optionally, in a top-down perspective of the solar cell, the maximum length of the particles is less than 50 nm; preferably, the maximum length of the particles is less than 20 nm; further preferably, the maximum length of the particles is less than 15 nm; further preferably, the maximum length of the particles ranges from 5 nm to 10 nm.

[0008] Optionally, the etched region has a plurality of the particles, and the area coverage of the particles is in a range of 0.01% to 60%.

[0009] Optionally, the particulate matter includes silicon; or, the particulate matter includes silicon and doping elements, wherein the type of doping elements included in the particulate matter is different from the type of doping elements in the transmission layer where the particulate matter is located.

[0010] Optionally, the particulate matter includes molten silicon particles.

[0011] Optionally, in a top-down view of the solar cell, the particles are at least one of circular, elliptical, and irregular in shape.

[0012] Optionally, the depth of the particles buried in the plane of the etching area ranges from 0 nm to 50 nm.

[0013] Optionally, in the thickness direction of the solar cell, 10% to 100% of the particles are buried in the plane where the etched region is located.

[0014] Optionally, the etching region is arranged in the first transmission layer, and the area of ​​the etching region accounts for 90% or less of the area of ​​the first transmission layer; and / or,

[0015] The etched region is arranged in the second transmission layer, and the area of ​​the etched region accounts for 90% or less of the area of ​​the second transmission layer.

[0016] Optionally, a plane where the etched region is located and a plane where the first transmission layer and / or the second transmission layer are away from the silicon substrate have a height difference D, 0 nm≤D≤100 nm.

[0017] Optionally, the particles are formed by laser etching.

[0018] Optionally, the first transmission layer includes a first passivation layer and a first doping layer arranged in a stacked manner, and the first passivation layer is connected to the first surface and the first doping layer; the second transmission layer includes a second passivation layer and a second doping layer arranged in a stacked manner, and the second passivation layer is connected to the first surface and the second doping layer; one of the first doping layer and the second doping layer is an N-type doping layer, and the other of the first doping layer and the second doping layer is a P-type doping layer.

[0019] Optionally, an end portion of the first transmission layer and an end portion opposite to the second transmission layer are stacked to form a stacked portion; the solar cell also includes a transparent conductive layer, the transparent conductive layer is connected to a portion of the surface of the first transmission layer facing away from the silicon substrate, and is connected to a portion of the surface of the second transmission layer facing away from the silicon substrate, and the transparent conductive layer has a third opening, and the third opening is used to disconnect the electrical connection between the first transmission layer and the second transmission layer.

[0020] Optionally, an isolation region is provided between the first transmission layer and the second transmission layer; the solar cell further comprises a transparent conductive layer, the transparent conductive layer being connected to a portion of the surface of the first transmission layer facing away from the silicon substrate, and being connected to a portion of the surface of the second transmission layer facing away from the silicon substrate, and the transparent conductive layer having a fourth opening, and the fourth opening being used to disconnect the electrical connection between the first transmission layer and the second transmission layer.

[0021] In a second aspect, an embodiment of the present invention further provides a photovoltaic assembly, the photovoltaic assembly comprising a cover plate, a back plate, and a solar cell disposed between the cover plate and the back plate; the solar cell comprises the solar cell as described above.

[0022] The present invention discloses a solar cell, wherein the first transmission layer is provided with an etched region, and / or the second transmission layer is provided with an etched region; the etched region has particles, and the particles can increase the back reflection of the front transmitted light, thereby improving the light absorption efficiency of the solar cell. Moreover, in the case where the first transmission layer is provided with an etched region, the plane where the etched region is located is lower than the plane where the first transmission layer is away from the silicon substrate, which can reduce the parasitic absorption of the first transmission layer and improve the light absorption efficiency. The plane where the etched region is located is flush with the plane where the first transmission layer is away from the silicon substrate. Although it is flush, there are particles in the etched region. Compared with the area without particles, the transmission path of light in the area where the particles are located is reduced, which can reduce the parasitic absorption of the first transmission layer and improve the light absorption efficiency. And, in the case where the second transmission layer is provided with an etched region, the plane where the etched region is located is lower than the plane where the second transmission layer is away from the silicon substrate, which can reduce the parasitic absorption of the second transmission layer and improve the light absorption efficiency. The plane where the etched area is located is flush with the plane of the second transmission layer away from the silicon substrate. Although it is flush, there are particles in the etched area. Compared with the area without particles, the light transmission path in the area with particles is reduced, which can reduce the parasitic absorption of the second transmission layer and improve the light absorption efficiency. Therefore, the solar cell of the embodiment of the present application has the advantage of high light absorption efficiency.

[0023] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for describing the embodiments are briefly introduced below.

[0025] Figures 1 to 7 A schematic diagram showing the steps of preparing a solar cell in an embodiment of the present invention is shown;

[0026] Figure 8 for Figure 3 Test image of the cross section shown;

[0027] Fig. 9 for Figure 4 Test image of the cross section shown;

[0028] Fig.10 Test image after coating the solar cell with a transparent conductive layer;

[0029] Fig.11 is a schematic structural diagram of a solar cell in an embodiment of the present invention;

[0030] Fig.12 It is a schematic structural diagram of a plane where particles of a solar cell are buried in an etched area in an embodiment of the present invention;

[0031] Fig.13 A schematic diagram of the structure of a solar cell particle in an embodiment of the present invention Figure 1 ;

[0032] Fig.14 A schematic diagram of the structure of a solar cell particle in an embodiment of the present invention Figure 2 .

[0033] Description of reference numerals:

[0034] 10-silicon substrate; 11-first surface; 12-second surface;

[0035] 20-first transmission layer; 21-first passivation layer; 22-first doping layer; 23-etching region; 231-plane where the etching region is located;

[0036] 30 - second transmission layer; 31 - second passivation layer; 32 - second doping layer;

[0037] 40-transparent conductive layer; 41-particles;

[0038] 50-laminated portion; 51-first opening; 52-second opening; 53-third opening;

[0039] 61 - first electrode; 62 - second electrode; 70 - third passivation layer; 80 - anti-reflection layer. DETAILED DESCRIPTION

[0040] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can also be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0041] Reference Figures 1 to 14 , which shows a schematic diagram of the preparation steps of a solar cell provided by an embodiment of the present invention. The embodiment of the present invention discloses a solar cell, which includes a silicon substrate 10, a first transmission layer 20 and a second transmission layer 30. The first surface 11 of the silicon substrate 10 is respectively provided with the first transmission layer 20 and the second transmission layer 30, and the first transmission layer and the second transmission layer are alternately arranged; the first transmission layer 20 is provided with an etching area 23, and the plane 231 where the etching area is located is lower than or flush with the plane of the first transmission layer 20 away from the silicon substrate 10; and / or, the second transmission layer 30 is provided with an etching area 23, and the plane 231 where the etching area is located is lower than or flush with the plane of the second transmission layer 30 away from the silicon substrate 10; there are particles 41 on the etching area 23.

[0042] Specifically, in the solar cell, the silicon substrate 10 has a first surface 11 and a second surface 12, and the first surface 11 and the second surface 12 are relatively distributed, that is, one of the first surface 11 and the second surface 12 is the front side of the silicon substrate 10, and the other of the first surface 11 and the second surface 12 is the back side of the silicon substrate 10.

[0043] Reference Figures 1 to 7 , Fig.11 As shown, the first surface 11 of the silicon substrate 10 is provided with a first transmission layer 20 and a second transmission layer 30, respectively, and the first transmission layer and the second transmission layer are arranged alternately and spaced apart; the alternating spacing is arranged as follows: one is in the plane extension direction of the silicon substrate 10, that is, in the first direction A, the first transmission layer 20 and the second transmission layer 30 are arranged alternately and spaced apart on the plane of the silicon substrate 10, and the two are in contact or non-contact in the plane extension direction of the silicon substrate 10. The other is in the plane extension direction of the silicon substrate 10, that is, in the first direction A, the first transmission layer 20 and the second transmission layer 30 are arranged alternately and spaced apart on the plane of the silicon substrate 10, and the two are partially overlapped in the thickness extension direction of the silicon substrate 10. The first transmission layer 20 and the second transmission layer 30 are of different types, one of the first transmission layer 20 and the second transmission layer 30 is an electron transmission layer, and the other of the first transmission layer 20 and the second transmission layer 30 is a hole transmission layer.

[0044] In the embodiment of the present application, the first transmission layer 20 is provided with an etched region 23, and / or the second transmission layer 30 is provided with an etched region 23; the etched region 23 has particles 41, and the particles 41 can increase the back reflection of the front transmitted light, thereby improving the light absorption efficiency of the solar cell. Moreover, in the case where the first transmission layer 20 is provided with an etched region 23, the plane 231 where the etched region is located is lower than the plane of the first transmission layer 20 away from the silicon substrate 10, which can reduce the parasitic absorption of the first transmission layer 20 and improve the light absorption efficiency. The plane 231 where the etched region is located is flush with the plane of the first transmission layer 20 away from the silicon substrate 10. Although it is flush, the etched region 23 has the presence of particles 41. Compared with the area without particles 41, the area with particles 41 has a reduced light transmission path, which can reduce the parasitic absorption of the first transmission layer 20 and improve the light absorption efficiency. Furthermore, when the second transmission layer 30 is provided with an etched region 23, the plane 231 where the etched region is located is lower than the plane where the second transmission layer 30 is away from the silicon substrate 10, which can reduce the parasitic absorption of the second transmission layer 30 and improve the light absorption efficiency. The plane 231 where the etched region is located is flush with the plane where the second transmission layer 30 is away from the silicon substrate 10. Although it is flush, the etched region 23 has the presence of particles 41. Compared with the area without particles 41, the area with particles 41 has a reduced transmission path of light, which can reduce the parasitic absorption of the second transmission layer 30 and improve the light absorption efficiency. Therefore, the solar cell of the embodiment of the present application has the advantage of high light absorption efficiency.

[0045] Reference Figure 7 As shown, in the embodiment of the present application, the thickness direction is the second direction Z, that is, the thickness of the transparent conductive layer 40, the thickness of the solar cell, the thickness of the silicon oxide layer, etc. are all in the second direction Z.

[0046] Optionally, the particles 41 are formed by laser etching.

[0047] The embodiment of the present application does not specifically limit the wavelength and energy of the laser. For example, a green laser is used with a wavelength of 532 nm and an energy of 53 μJ. For example, the wavelength of the laser is 355 nm.

[0048] Optionally, in a top view of the solar cell, the maximum length of the particle 41 is less than 50 nm; preferably, the maximum length of the particle 41 is less than 20 nm; further preferably, the maximum length of the particle 41 is less than 15 nm; further preferably, the maximum length of the particle 41 is in the range of 5 nm to 10 nm. When the size of the particle 41 is within the above range, the particle 41 can increase the back reflection of the front transmitted light, thereby improving the light absorption efficiency.

[0049] Further, the maximum length of the particle 41 is less than 50nm, and the light refraction effect is good. Further, the maximum length of the particle 41 is less than 20nm, and the light refraction index effect is good, and the contact resistance effect is better than that of the particle 41 with a maximum length less than 50nm. Further, the maximum length of the particle 41 is within the range of 5nm-10nm, and the light refraction index effect and the contact resistance effect are optimal.

[0050] Furthermore, in the top view of the solar cell, the maximum length value of the particle 41 is not specifically limited in the embodiment of the present application. For example, the maximum length of the particle 41 is 5nm, 5.5nm, 6nm, 6nm, 7nm, 8nm, 9nm, 10nm, 11nm, 12nm, 13nm, nm, 14nm, 15nm, 16nm, 17nm, 18nm, 19nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, nm, 50nm, etc.

[0051] Optional, see Fig.10 As shown, there are a plurality of particles 41 on the etched area 23, and the area coverage of the particles 41 ranges from 0.01% to 60%, so as to ensure that the particles 41 can increase the back reflection of the front transmitted light, thereby improving the light absorption efficiency of the solar cell.

[0052] Optionally, the particles 41 include silicon; or the particles 41 include silicon and doping elements, wherein the type of doping elements included in the particles 41 is different from the type of doping elements in the transmission layer in which the particles 41 are located.

[0053] In the embodiment of the present application, the particle 41 is formed after laser etching, and the particle 41 includes silicon. Alternatively, the particle 41 includes silicon and a doping element, and the doping element is at least one of the three group elements, or at least one of the five group elements (nitrogen, phosphorus, arsenic, etc.). For example, the three group elements are at least one of boron, aluminum, gallium, indium, etc., and the five group elements are at least one of nitrogen, phosphorus, arsenic, antimony, etc.

[0054] For example, if the doping element included in the particle 41 is boron, then the doping element in the first transmission layer where the particle 41 is located is phosphorus. For another example, if the doping element included in the particle 41 is phosphorus, then the doping element in the second transmission layer where the particle 41 is located is boron.

[0055] Optionally, the particles 41 include molten silicon particles.

[0056] In the embodiment of the present application, particles 41 are formed after laser etching. The particles 41 include molten silicon particles. The silicon particles include silicon element; or, the silicon particles include silicon element and doping elements.

[0057] Optionally, in a top view of the solar cell, the particles 41 are in at least one of a circular shape, an elliptical shape, and an irregular shape.

[0058] Further references Fig.13 , which shows a schematic diagram of the structure of the particles 41 in a circular shape. Fig.14 , which shows a schematic structural diagram of the particle 41 being elliptical.

[0059] Optionally, the depth of the particles 41 buried in the plane 231 where the etched region is located ranges from 0 nm to 50 nm.

[0060] In the embodiment of the present application, the depth of the particle 41 buried in the plane 231 where the etching area is located is set according to usage requirements. For example, the depth of the particle 41 buried in the plane 231 where the etching area is located is 0nm, 5nm, 10nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 48nm, and 50nm.

[0061] Optional, see Fig.12 As shown, in the thickness direction of the solar cell, 10% to 100% of the particles 41 are buried in the plane 231 where the etched region is located.

[0062] Further references Fig.12 As shown, from top to bottom, in the first figure, the plane 231 where the 10% buried etching area of ​​the particle 41 is located is shown; in the second figure, the plane 231 where the 25% buried etching area of ​​the particle 41 is located is shown; in the third figure, the plane 231 where the 50% buried etching area of ​​the particle 41 is located is shown; in the fourth figure, the plane 231 where the 75% buried etching area of ​​the particle 41 is located is shown; in the fifth figure, the plane 231 where the 100% buried etching area of ​​the particle 41 is located is shown; and in the sixth figure, the inside of the plane 231 where all the buried etching areas of the particle 41 are located is shown.

[0063] Optional, see Figures 1 to 7 As shown, the etched region 23 is disposed in the first transmission layer 20, and the area of ​​the etched region 23 accounts for 90% or less of the area of ​​the first transmission layer 20. At this time, the etched region 23 can increase the back reflection of the front transmitted light, thereby improving the light absorption efficiency of the solar cell.

[0064] Optionally, the end portion of the first transmission layer 20 is stacked with the end portion opposite to the second transmission layer 30, and the end portion of the first transmission layer 20 is located between the end portion opposite to the second transmission layer 30 and the first surface 11; the first transmission layer 20 is provided with an etched region 23 except the end portion of the first transmission layer 20. In the above structure of the solar cell of the embodiment of the present application, the area of ​​the etched region 23 is large, thereby effectively improving the light absorption efficiency. Moreover, the etched region 23 can be formed by laser etching in the etching process of the solar cell, which can save process steps.

[0065] Optional, see Figures 1 to 4 As shown, there is a height difference D between the plane 231 where the etched region is located and the plane of the first transmission layer 20 and / or the second transmission layer 30 away from the silicon substrate 10, 0 nm≤D≤100 nm.

[0066] In practical applications, the height difference D between the etched area 23 and the first transmission layer 20 and / or the second transmission layer 30 can be selected according to usage requirements. For example, D is 0nm, 1nm, 5nm, 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, or 100nm.

[0067] Optional, see Figure 1 As shown, the first transmission layer 20 includes a first passivation layer 21 and a first doping layer 22 which are stacked, and the first passivation layer 21 is connected to the first surface 11 and the first doping layer 22. Figure 3 As shown, the second transport layer 30 includes a second passivation layer 31 and a second doping layer 32 arranged in a stacked manner, the second passivation layer 31 is connected to the first surface 11 and the second doping layer 32; one of the first doping layer 22 and the second doping layer 32 is an N-type doping layer, and the other of the first doping layer 22 and the second doping layer 32 is a P-type doping layer. The first transport layer 20 or the second transport layer 30 with an N-type doping layer is an electron transport layer, and the first transport layer 20 or the second transport layer 30 with a P-type doping layer is a hole transport layer.

[0068] Optionally, the material of the first passivation layer 21 and the material of the second passivation layer 31 both include intrinsic amorphous silicon, and the material of the first doping layer 22 and the material of the second doping layer 32 both include one or more of doped polysilicon, doped microcrystalline silicon, and doped amorphous silicon. That is, the material of the first passivation layer 21 and the material of the second passivation layer 31 both include intrinsic amorphous silicon, and the material of the first doping layer 22 and the material of the second doping layer 32 both include doped polycrystalline silicon. Alternatively, the material of the first passivation layer 21 and the material of the second passivation layer 31 both include intrinsic amorphous silicon, and the material of the first doping layer 22 and the material of the second doping layer 32 both include doped microcrystalline silicon. Alternatively, the material of the first passivation layer 21 and the material of the second passivation layer 31 both include intrinsic amorphous silicon, and the material of the first doping layer 22 and the material of the second doping layer 32 both include intrinsic amorphous silicon. Alternatively, the material of the first passivation layer 21 and the material of the second passivation layer 31 both include intrinsic amorphous silicon, and the material of the first doping layer 22 and the material of the second doping layer 32 both include two or three of doped polycrystalline silicon, doped microcrystalline silicon, and doped amorphous silicon.

[0069] Optionally, the material of the first passivation layer 21 and the material of the second passivation layer 31 both include silicon oxide, and the material of the first doping layer 22 and the material of the second doping layer 32 both include doped polysilicon.

[0070] Optionally, the material of the first passivation layer 21 includes intrinsic amorphous silicon, and the material of the first doping layer 22 includes one or more of doped polysilicon, doped microcrystalline silicon, and doped amorphous silicon; and the material of the second passivation layer 31 includes silicon oxide, and the material of the first doping layer 22 includes doped polysilicon. That is, the material of the first passivation layer 21 includes intrinsic amorphous silicon, and the material of the first doping layer 22 includes doped polysilicon; the material of the second passivation layer 31 includes silicon oxide, and the material of the first doping layer 22 includes doped polysilicon. Alternatively, the material of the first passivation layer 21 includes intrinsic amorphous silicon, and the material of the first doping layer 22 includes doped polysilicon; the material of the second passivation layer 31 includes silicon oxide, and the material of the first doping layer 22 includes doped polysilicon. Alternatively, the material of the first passivation layer 21 includes intrinsic amorphous silicon, and the material of the first doping layer 22 includes doped polysilicon; the material of the second passivation layer 31 includes silicon oxide, and the material of the first doping layer 22 includes doped polysilicon. Alternatively, the material of the first passivation layer 21 includes intrinsic amorphous silicon, and the material of the first doping layer 22 includes doped polysilicon; the material of the second passivation layer 31 includes silicon oxide, and the material of the first doping layer 22 includes doped polysilicon. Alternatively, the material of the first passivation layer 21 includes intrinsic amorphous silicon, the material of the first doping layer 22 includes two or three of doped polysilicon, doped microcrystalline silicon, and doped amorphous silicon; the material of the second passivation layer 31 includes silicon oxide, and the material of the first doping layer 22 includes doped polysilicon.

[0071] Optionally, the material of the first passivation layer 21 includes silicon oxide, and the material of the first doping layer 22 includes doped polysilicon; and the material of the second passivation layer 31 includes intrinsic amorphous silicon, and the material of the second doping layer 32 includes one of doped polysilicon, doped microcrystalline silicon, and doped amorphous silicon. That is, the material of the first passivation layer 21 includes silicon oxide, and the material of the first doping layer 22 includes doped polycrystalline silicon; the material of the second passivation layer 31 includes intrinsic amorphous silicon, and the material of the second doping layer 32 includes doped polycrystalline silicon. Alternatively, the material of the first passivation layer 21 includes silicon oxide, and the material of the first doping layer 22 includes doped polycrystalline silicon; the material of the second passivation layer 31 includes intrinsic amorphous silicon, and the material of the second doping layer 32 includes doped microcrystalline silicon. Alternatively, the material of the first passivation layer 21 includes silicon oxide, and the material of the first doping layer 22 includes doped polycrystalline silicon; the material of the second passivation layer 31 includes intrinsic amorphous silicon, and the material of the second doping layer 32 includes intrinsic amorphous silicon. Alternatively, the material of the first passivation layer 21 includes silicon oxide, the material of the first doping layer 22 includes doped polysilicon; the material of the second passivation layer 31 includes intrinsic amorphous silicon, and the material of the second doping layer 32 includes two or three of doped polysilicon, doped microcrystalline silicon, and doped amorphous silicon.

[0072] Optional, see Figures 1 to 7 As shown, the end portion of the first transmission layer 20 and the end portion opposite to the second transmission layer 30 are stacked to form a stacked portion 50; the solar cell also includes a transparent conductive layer 40, which is connected to the portion of the surface of the first transmission layer 20 that is away from the silicon substrate 10, and is connected to the portion of the surface of the second transmission layer 30 that is away from the silicon substrate 10, and the transparent conductive layer 40 has a third opening, which is used to disconnect the electrical connection between the first transmission layer 20 and the second transmission layer 30.

[0073] The third opening 53 prevents the N region and the P region from being connected. The third opening 53 can be used for insulating the N region and the P region, and has the advantages of good insulation reliability and insulation effect.

[0074] Optional, see Figures 1 to 7 As shown, there is an isolation region between the first transmission layer 20 and the second transmission layer 30; the solar cell further includes a transparent conductive layer 40, which is connected to the surface of the first transmission layer 20 that is away from the silicon substrate 10, and is connected to the surface of the second transmission layer 30 that is away from the silicon substrate 10, and the transparent conductive layer 40 has a fourth opening, which is used to disconnect the electrical connection between the first transmission layer 20 and the second transmission layer 30. In the above structure of the present application, the fourth opening also insulates the N region and the P region, which has the advantages of good insulation reliability and insulation effect.

[0075] Optional, see Figures 1 to 7As shown, the solar cell also includes a first electrode 61 and a second electrode 62. The transparent conductive layer 40 is located at the first transmission layer 20 and the first electrode 61 is provided on the surface facing away from the silicon substrate 10. The transparent conductive layer 40 is located at the second transmission layer 30 and the second electrode 62 is provided on the surface facing away from the silicon substrate 10.

[0076] Furthermore, a third opening 53 is provided between the first electrode 61 and the second electrode 62, and the first electrode 61 and the second electrode 62 are insulated by the third opening 53. The first electrode 61 and the second electrode 62 are arranged parallel to the extension direction of the laminated portion 50 and are spaced apart.

[0077] Optional, see Figure 1 and Figure 3 As shown, the solar cell further includes an anti-reflection layer 80 and a third passivation layer 70 , and the anti-reflection layer 80 and the third passivation layer 70 are sequentially stacked and arranged on the second surface 12 of the solar cell.

[0078] The present invention also provides a photovoltaic assembly, which includes a cover plate, a back plate, and a solar cell arranged between the cover plate and the back plate; the solar cell includes the solar cell as described above.

[0079] The embodiments of the present application do not specifically limit whether the photovoltaic module includes other structures. For example, the photovoltaic module may also include: a first packaging film disposed between the cover plate and the solar cell, and a second packaging film disposed between the back plate and the solar cell.

[0080] In the solar cell of the photovoltaic module, when the first transmission layer 20 is provided with an etched region 23, the plane 231 where the etched region is located is lower than the plane of the first transmission layer 20 away from the silicon substrate 10, which can reduce the parasitic absorption of the first transmission layer 20 and improve the light absorption efficiency. The plane 231 where the etched region is located is flush with the plane of the first transmission layer 20 away from the silicon substrate 10. Although it is flush, the etched region 23 has particles 41. Compared with the area without particles 41, the area with particles 41 has a reduced transmission path of light, which can reduce the parasitic absorption of the first transmission layer 20 and improve the light absorption efficiency. And, when the second transmission layer 30 is provided with an etched region 23, the plane 231 where the etched region is located is lower than the plane of the second transmission layer 30 away from the silicon substrate 10, which can reduce the parasitic absorption of the second transmission layer 30 and improve the light absorption efficiency. The plane 231 where the etched area is located is flush with the plane of the second transmission layer 30 away from the silicon substrate 10. Although flush, the etched area 23 has particles 41. Compared with the area without particles 41, the area with particles 41 has a reduced light transmission path, which can reduce the parasitic absorption of the second transmission layer 30 and improve the light absorption efficiency. The photovoltaic module of the embodiment of the present application has the advantage of high conversion efficiency.

[0081] The present invention is further described in detail below with reference to specific embodiments.

[0082] Embodiment 1

[0083] The preparation process of solar cells includes the following steps:

[0084] 101, such as Figure 1 As shown, a first transmission layer 20 is formed on the first surface 11 of the silicon substrate 10 .

[0085] In this step, the first transmission layer 20 is a first passivation layer 21 and a first doping layer 22 stacked, and the first passivation layer 21 is connected to the first surface 11 and the first doping layer 22. Specifically, a low pressure chemical vapor deposition (LPCVD) device can be used to sequentially deposit the first passivation layer 21 and the first doping layer 22 on the first surface 11. Among them, the silicon substrate 10 is an N-type silicon substrate, and the first passivation layer 21 includes a silicon oxide layer, and the thickness of the silicon oxide layer ranges from 0.5nm to 5nm. The first doping layer 22 is an N-type polysilicon layer, and the thickness of the N-type polysilicon layer ranges from 30nm to 200nm.

[0086] 102, such as Figure 2 As shown, the first transmission layer 20 is etched to form a first opening 51 .

[0087] In this step, photolithography or mask etching can be used for patterning to remove the removal area of ​​the first transmission layer 20 to form the first opening 51, specifically, the first passivation layer 21 and the first doping layer 22 are removed to form the first opening 51. The width of the first opening 51 ranges from 100 μm to 800 μm.

[0088] 103, such as Figure 3 As shown, a second transmission layer 30 is deposited on a first surface 11 of the silicon substrate 10 , and a third passivation layer 70 and an anti-reflection layer 80 are deposited on a second surface 12 of the silicon substrate 10 .

[0089] The second transmission layer 30 includes a second passivation layer 31 and a second doping layer 32, wherein the second passivation layer 31 is connected between the second doping layer 32 and the first surface 11. The second passivation layer 31 and the second doping layer 32 may be sequentially deposited by a chemical vapor deposition (CVD) device. The second passivation layer 31 is an intrinsic passivation layer, and the thickness of the second passivation layer 31 is in the range of 3nm-10nm. The second doping layer 32 is a p-type amorphous silicon layer, and the thickness of the second doping layer 32 is in the range of 5-20nm.

[0090] A third passivation layer 70 may be deposited on the second surface 12 of the silicon substrate 10 by using a CVD device. The third passivation layer 70 is an intrinsic passivation layer or a silicon oxide layer. The thickness of the third passivation layer 70 is in the range of 2nm-20nm. An anti-reflection layer 80 is deposited on the third passivation layer 70. The thickness of the anti-reflection layer 80 is in the range of 50nm-200nm.

[0091] Further, such as Figure 8 , which shows Figure 3 A test diagram showing the positions of the first passivation layer 21, the first doping layer 22, the second passivation layer 31, and the second doping layer 32 stacked in sequence. The total thickness of the first passivation layer 21, the first doping layer 22, the second passivation layer 31, and the second doping layer 32 is 137 nm.

[0092] 104, such as Figure 4 , the second passivation layer 31 , the second doping layer 32 , and a portion of the first doping layer 22 are etched away using laser to form a second opening 52 .

[0093] In this step, an etched region 23 is provided on the first transmission layer 20 , and particles 41 remaining after the second passivation layer 31 and the second doping layer 32 are etched by laser are present on the etched region 23 .

[0094] Moreover, the plane 231 where the etched area is located is lower than the plane of the first transmission layer 20 away from the silicon substrate 10, and the first doping layer 22 is thinned. The benefit of thinning the first doping layer 22 is that the parasitic absorption of the first doping layer 22 is reduced, which is conducive to improving the conversion efficiency.

[0095] Further, such as Fig. 9 , which shows a side view of the cross section of the opening area after the second opening 52 is formed by the laser process, which shows the total thickness of the first passivation layer 21 and part of the first doping layer 22, which is 90nm. A green laser is used, the wavelength of the laser is 532nm, and the energy used is 53μJ.

[0096] Molten particles 41 are formed on the etched area 23. Scanning electron microscope (SEM) test is performed on the etched area 23. The maximum length range of the particles 41 is more concentrated within 10 nm. The particles 41 within 10 nm can increase the back reflection of the front transmitted light.

[0097] 105, such as Figure 5 , a transparent conductive layer 40 is deposited on the side of the silicon substrate 10 where the first surface 11 is provided.

[0098] In this step, a physical vapor deposition (PVD) device may be used to deposit the transparent conductive layer 40 entirely on the first doping layer 22 and the second doping layer 32 . The thickness of the transparent conductive layer 40 is in the range of 20 nm to 200 nm.

[0099] like Fig.10 , which shows a test image after a finished solar cell is manufactured. In the test image, particles 41 can be seen on the surface of the first doping layer 22 .

[0100] 106, such as Figure 6 , a portion of the transparent conductive layer 40 is etched to form a third opening 53 .

[0101] In this step, photolithography may be used to remove a portion of the transparent conductive layer 40 in the insulating region to form a third opening 53 , wherein the third opening 53 is used to insulate the N region from the P region.

[0102] 107, such as Figure 7 , a first electrode 61 is prepared on the transparent conductive layer 40 corresponding to the N region, and a second electrode 62 is prepared on the transparent conductive layer 40 corresponding to the P region by screen printing.

[0103] The first electrode 61 and the second electrode 62 are both metal electrodes. For example, the materials of the first electrode 61 and the second electrode 62 both include silver.

[0104] Embodiment 2

[0105] The difference from the first embodiment is the difference in the cell type: the material of the first passivation layer 21 and the material of the second passivation layer 31 both include intrinsic amorphous silicon, and the material of the first doping layer 22 and the material of the second doping layer 32 both include one or more of doped polycrystalline silicon, doped microcrystalline silicon, and doped amorphous silicon. The solar cell formed in the second embodiment is an HBC cell. The rest of the second embodiment is the same as the first embodiment.

[0106] Embodiment 3

[0107] The difference from the first embodiment is the difference in the cell type: the material of the first passivation layer 21 and the material of the second passivation layer 31 both include silicon oxide, and the material of the first doping layer 22 and the material of the second doping layer 32 both include doped polysilicon. The solar cell formed in the third embodiment is a TBC cell. The rest of the third embodiment is the same as the first embodiment.

[0108] Embodiment 4

[0109] The difference from the first embodiment is the difference in the cell type: the material of the first passivation layer 21 includes intrinsic amorphous silicon, the material of the first doping layer 22 includes one of doped polycrystalline silicon, doped microcrystalline silicon, and doped amorphous silicon; and the material of the second passivation layer 31 includes silicon oxide, and the material of the first doping layer 22 includes doped polycrystalline silicon. The solar cell formed in the second embodiment is a combined passivation back contact cell.

[0110] The rest of the fourth embodiment is the same as the first embodiment.

[0111] Comparative Example 5

[0112] The difference from the first embodiment is that the energy of the laser is different, and the rest of the parts are the same as those of the first embodiment.

[0113] like Fig.10 , which shows a test image of a solar cell after the transparent conductive layer 40 is plated. It can still be seen that particles 41 are present on the surface of the first doping layer 22 .

[0114] Comparative Example

[0115] The difference from the first embodiment is that there is no particle 41 on the first doping layer 22 , that is, the first doping layer 22 has no particle, and the rest of the parts are the same as those of the first embodiment.

[0116] The 1000 solar cells formed in Example 1 and the 1000 solar cells formed in the comparative example were subjected to performance tests under the same test conditions. The test results are shown in Table 1 below.

[0117] <![CDATA[Jsc(A / cm 2 )]]> Voc(mV) FF(%) Eff(%) Comparative Example 40.8 739 83.1 25.06 Embodiment 1 41.8 739 83.2 25.17

[0118] In Table 1, the data of Example 1 are the results of arithmetic averaging the test results of 1000 solar cells corresponding to Example 1, and the data of the comparative example are the results of arithmetic averaging the test results of 1000 solar cells corresponding to the comparative example. In Table 1, Jsc represents the short-circuit current density of the solar cell, and Voc represents the open-circuit voltage of the solar cell. FF represents the fill factor of the solar cell, and Eff represents the photoelectric conversion efficiency of the solar cell. It can be concluded from Table 1 above that the photoelectric conversion efficiency of Example 1 is higher than that of the comparative example. The main reason is that in Example 1, the second passivation layer 31 and the second doping layer 32 in the second opening 52 are laser etched to form particles 41 in the first transmission layer 20. In addition, the laser etching thins part of the first doping layer 22 in the second opening 52. The particles 41 can increase the back reflection of the front transmitted light and improve the light absorption efficiency. In addition, the thinning of part of the first doping layer 22 can reduce the parasitic absorption of the first doping layer 22, which is beneficial to improve the conversion efficiency.

[0119] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0120] Each embodiment in this specification is described in a related manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. For the embodiments of the device, electronic device, computer-readable storage medium and computer program products containing instructions, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiments.

[0121] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A solar cell, characterized in that: The solar cell comprises a silicon substrate, a first transmission layer and a second transmission layer, the first surface of the silicon substrate is provided with the first transmission layer and the second transmission layer respectively, and the first transmission layer and the second transmission layer are alternately arranged; The first transmission layer is provided with an etched region, and the plane where the etched region is located is lower than or flush with the plane of the first transmission layer away from the silicon substrate; and / or the second transmission layer is provided with an etched region, and the plane where the etched region is located is lower than or flush with the plane of the second transmission layer away from the silicon substrate; The etched region has particles, and the particles include silicon.

2. The solar cell according to claim 1, characterized in that: In a top-down view of the solar cell, the maximum length of the particles is less than 50 nm.

3. The solar cell according to claim 1, characterized in that The etched region has a plurality of the particles, and the area coverage of the particles on the etched region ranges from 0.01% to 60%.

4. The solar cell according to claim 1, characterized in that The particles include silicon and doping elements, wherein the type of the doping elements included in the particles is different from the type of the doping elements in the transmission layer where the particles are located.

5. The solar cell according to claim 1, characterized in that: The particulate matter includes molten silicon particles.

6. The solar cell according to claim 1, characterized in that In a top view of the solar cell, the particles are in at least one of a circular shape, an elliptical shape, and an irregular shape.

7. The solar cell according to claim 1, characterized in that The depth of the particles buried in the plane where the etching area is located ranges from 0 nm to 50 nm.

8. The solar cell according to claim 1, characterized in that In the thickness direction of the solar cell, 10% to 100% of the particles are buried in the plane where the etched region is located.

9. The solar cell according to claim 1, characterized in that: The etching region is arranged in the first transmission layer, and the area of ​​the etching region accounts for 90% or less of the area of ​​the first transmission layer; and / or, The etched region is arranged in the second transmission layer, and the area of ​​the etched region accounts for 90% or less of the area of ​​the second transmission layer.

10. The solar cell according to claim 1, characterized in that: There is a height difference D between a plane where the etched region is located and a plane where the first transmission layer and / or the second transmission layer is away from the silicon substrate, and 0 nm≤D≤100 nm.

11. The solar cell according to claim 1, characterized in that: The particles are formed by laser etching.

12. The solar cell according to claim 1, characterized in that The first transmission layer includes a first passivation layer and a first doping layer arranged in a stacked manner, and the first passivation layer is connected to the first surface and the first doping layer; the second transmission layer includes a second passivation layer and a second doping layer arranged in a stacked manner, and the second passivation layer is connected to the first surface and the second doping layer; one of the first doping layer and the second doping layer is an N-type doping layer, and the other of the first doping layer and the second doping layer is a P-type doping layer.

13. The solar cell according to claim 1, characterized in that The end portion of the first transmission layer and the end portion opposite to the second transmission layer are stacked to form a stacked portion; The solar cell also includes a transparent conductive layer, which is connected to a portion of the surface of the first transmission layer facing away from the silicon substrate, and is connected to a portion of the surface of the second transmission layer facing away from the silicon substrate, and the transparent conductive layer has a third opening, and the third opening is used to disconnect the electrical connection between the first transmission layer and the second transmission layer.

14. The solar cell according to claim 1, characterized in that An isolation region is provided between the first transmission layer and the second transmission layer; The solar cell also includes a transparent conductive layer, which is connected to a portion of the surface of the first transmission layer facing away from the silicon substrate, and is connected to a portion of the surface of the second transmission layer facing away from the silicon substrate, and the transparent conductive layer has a fourth opening, and the fourth opening is used to disconnect the electrical connection between the first transmission layer and the second transmission layer.

15. A photovoltaic module, characterized in that: The photovoltaic assembly includes a cover plate, a back plate, and a solar cell disposed between the cover plate and the back plate; the solar cell includes the solar cell according to any one of claims 1 to 14.

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