Bifacial solar cell, battery module and photovoltaic system

Abstract

The present invention is applicable to the technical field of solar cells. Provided are a bifacial solar cell (100), a battery module (200) and a photovoltaic system (1000). In the bifacial solar cell (100), a silicon substrate (10) has a first surface (11) and a second surface (12), which are opposite each other, wherein a first doped layer (20) is located on the first surface (11), and is provided with several first electrode arrangement regions (21); several first barrier layers (30) are located on the first electrode arrangement regions (21) and are arranged at intervals in a first predetermined direction, such that each first electrode arrangement region (21) comprises a first shielded region (212) shielded by the corresponding first barrier layer (30) and a first non-shielded region (211) not shielded by the corresponding first barrier layer (30); a first passivation film layer (40) covers the first barrier layers (30) and the first doped layer (20); a first grid line electrode (50) is arranged in the first electrode arrangement regions (21) and is located above the first doped layer (20) and the first barrier layers (30); the first grid line electrode (50) is made of a fire-through paste; at the first shielded regions (212), the first grid line electrode (50) penetrates the first passivation film layer (40) to come into contact with the first barrier layers (30) but not come into contact with the first doped layer (20); and at the first non-shielded regions (211), the first grid line electrode (50) penetrates the first passivation film layer (40) to come into contact with the first doped layer (20).

Description

Bifacial solar cells, battery modules and photovoltaic systems

[0001] Priority information

[0002] This application claims priority and benefits of patent application No. 202311780305.4 filed with the State Intellectual Property Office of China on December 22, 2023, and the entire text of which is incorporated herein by reference. Technical Field

[0003] The present invention relates to the technical field of solar cells, and in particular to a double-sided solar cell sheet, a cell assembly and a photovoltaic system. Background Art

[0004] Solar cell power generation is a sustainable, clean energy source that utilizes the photovoltaic effect of a semiconductor pn junction to convert sunlight into electricity. Currently, in bifacial solar cells (such as Topcon solar cells), a doped layer is formed on the front side of the silicon wafer, and a doped layer of the opposite polarity is formed on the back side. Passivation films and secondary gates are also applied on both the front and back sides.

[0005] In the related art, the auxiliary grid can be made of non-burn-through paste or burn-through paste. When using non-burn-through paste, it is necessary to punch holes in the passivation film layer. The process is complicated and prone to laser damage. In order to avoid this problem, burn-through paste is usually used to make the auxiliary grid. In the process of printing the paste to form the electrode, the auxiliary grid paste burns through the passivation film layer and directly contacts the doping layer below. Summary of the Invention

[0006] The present invention provides a double-sided solar cell sheet, a battery string, a battery assembly and a photovoltaic system.

[0007] The present invention is implemented as follows: a double-sided solar cell according to an embodiment of the present invention comprises:

[0008] a silicon substrate having a first surface and a second surface opposite to each other;

[0009] a first doping layer located on the first surface, the first doping layer having a plurality of first electrode arrangement regions;

[0010] a plurality of first barrier layers located on the first electrode arrangement region, wherein the plurality of first barrier layers are arranged in an interval along a first predetermined direction so that the first electrode arrangement region includes a first shielding region shielded by the first barrier layers and a first non-shielding region not shielded by the first barrier layers;

[0011] a first passivation film layer, wherein the first passivation film layer covers the first barrier layer and the first doping layer;

[0012] a first gate line electrode extending along the first predetermined direction, the first gate line electrode being arranged in the first electrode arrangement region and being located above the first doping layer and the first barrier layer, the first gate line electrode being made of a fire-through paste;

[0013] Among them, in the first blocking area, the first gate line electrode passes through the first passivation film layer and contacts the first blocking layer but does not contact the first doping layer; in the first non-blocking area, the first gate line electrode passes through the first passivation film layer and contacts the first doping layer.

[0014] The present invention also provides a battery assembly, which includes a plurality of the above-mentioned double-sided solar cells.

[0015] The present invention also provides a photovoltaic system, which includes the above-mentioned battery assembly.

[0016] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG1 is a schematic structural diagram of a photovoltaic system provided by an embodiment of the present invention;

[0018] FIG2 is a schematic diagram of the planar structure of a double-sided solar cell provided in an embodiment of the present invention;

[0019] FIG3 is a schematic cross-sectional view of the bifacial solar cell along line III-III in FIG2 ;

[0020] FIG4 is a schematic cross-sectional view of the bifacial solar cell along line IV-IV in FIG2 ;

[0021] FIG5 is another cross-sectional schematic diagram of the bifacial solar cell along line III-III in FIG2 ;

[0022] FIG6 is another schematic cross-sectional view of the bifacial solar cell along line III-III in FIG2 ;

[0023] FIG7 is another cross-sectional schematic diagram of the bifacial solar cell along line IV-IV in FIG2 ;

[0024] FIG8 is another schematic cross-sectional view of the bifacial solar cell along line III-III in FIG2 ;

[0025] FIG9 is another cross-sectional schematic diagram of the bifacial solar cell along line III-III in FIG2 ;

[0026] FIG10 is another schematic cross-sectional view of the bifacial solar cell along line IV-IV in FIG2 . Modes for Carrying Out the Invention

[0027] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. It should be noted that the embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and are not to be construed as limiting the present invention. In addition, it should be understood that the specific embodiments described herein are merely used to explain the present invention and are not intended to limit the present invention.

[0028] In the description of the present invention, it should be understood that the terms "up", "down", "left", "right", "horizontal", "longitudinal", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0029] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, "several" means two or more, unless otherwise specifically defined.

[0030] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0031] The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numbers and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but a person of ordinary skill in the art will recognize the application of other processes and / or the use scenarios of other materials.

[0032] Example 1

[0033] 1 , a photovoltaic system 1000 according to an embodiment of the present invention may include a battery assembly 200 according to an embodiment of the present invention. The battery assembly 200 according to an embodiment of the present invention may include a plurality of bifacial solar cells 100 according to an embodiment of the present invention.

[0034] Specifically, in the present invention, multiple bifacial solar cells 100 in a battery assembly 200 can be serially connected via welding ribbons to form a battery string. The battery strings in the battery assembly 200 can be connected in series, in parallel, or in a combination of series and parallel to achieve current bus output. For example, bus bars can be used to connect the battery strings.

[0035] 2 to 4 , a bifacial solar cell 100 in an embodiment of the present invention may include a silicon substrate 10 , a first doping layer 20 , a plurality of first barrier layers 30 , a first passivation film 40 , and a first gate electrode 50 .

[0036] As shown in FIG3 , a silicon substrate 10 has a first surface 11 and a second surface 12 that are opposite to each other, representing the front and back sides of the silicon substrate 10, respectively. The details are not limited herein. A first doped layer 20 is located on the first surface 11. The first doped layer 20 has a plurality of first electrode placement regions 21. A plurality of first barrier layers 30 are located on the first electrode placement regions 21 and are arranged in a spaced arrangement along a first predetermined direction. The first electrode placement regions 21 include first shielding regions 212 shielded by the first barrier layers 30 and first non-shielding regions 211 not shielded by the first barrier layers 30.

[0037] The first passivation film layer 40 covers the first barrier layer 30 and the first doping layer 20. The first gate line electrode 50 extends along the first predetermined direction. The first gate line electrode 50 is disposed in the first electrode arrangement region 21 and is located above the first doping layer 20 and the first barrier layer 30. The first gate line electrode 50 is made of a fire-through paste.

[0038] 3 , in the first blocking area 212 , the first gate line electrode 50 penetrates the first passivation film layer 40 and contacts the first barrier layer 30 and does not contact the first doping layer 20 ; in the first non-blocking area 211 , the first gate line electrode 50 penetrates the first passivation film layer 40 and contacts the first doping layer 20 (it should be noted that, since FIG. 3 is a cross-sectional view along the extension direction of the first gate line electrode 50 , at this position, the first passivation film layer 40 is substantially completely ablated, and therefore, the first passivation film layer 40 is not shown in FIG. 3 ).

[0039] In the related art, at the auxiliary gate position, the burn-through slurry usually burns through the passivation film layer and contacts the entire doping layer below, that is, the auxiliary gate is in full contact with the doping layer, and the passivation film layer cannot be selectively burned through. This will cause the contact area between the auxiliary gate and the doping layer to be too large, resulting in more serious recombination in the metallization area, thereby reducing the conversion efficiency.

[0040] In the bifacial solar cell 100, the battery assembly 200, and the photovoltaic system 1000 according to the embodiments of the present invention, a plurality of first barrier layers 30 are spaced apart along a first predetermined direction on the first electrode arrangement region 21 of the first doped layer 20. A first gate electrode 50 is also disposed along the first predetermined direction on the first electrode arrangement region 21. In the first shielding region 212, the first gate electrode 50 penetrates the first passivation film layer 40 and contacts the first barrier layer 30, but does not contact the first doped layer 20. In the first non-shielding region 211, the first gate electrode 50 penetrates the first passivation film layer 40 and contacts the first doped layer 20.

[0041] In this way, when using the burn-through paste to manufacture the first gate electrode 50, the first gate electrode 50 will only burn through the first passivation film layer 40 in the first non-blocking area 211 to achieve contact with the first doped layer 20, while in the first blocking area 212, it will only burn through the first passivation film layer 40 to make contact with the first barrier layer 30 without direct contact with the first doped layer 20. In this way, selective burn-through of the burn-through paste can be achieved, which can reduce the metallized contact area between the first gate electrode 50 and the first doped layer 20, reduce the recombination of the metallized area, and thus improve the conversion efficiency of the bifacial solar cell 100.

[0042] Specifically, in the embodiment of the present invention, the bifacial solar cell 100 can be a PERC solar cell or a Topcon solar cell, without limitation. Preferably, it is a Topcon solar cell. When it is a Topcon solar cell, it can be a single-sided Topcon solar cell or a bifacial Topcon solar cell, without limitation.

[0043] In the present invention, the first surface 11 and the second surface 12 can be the front and back sides of the silicon substrate 10 respectively. The silicon substrate 10 can be a P-type silicon substrate or an N-type silicon substrate. The first doped layer 20 can be a P-type doped layer or an N-type doped layer. The first doped layer 20 can be formed on the first surface 11 of the silicon wafer by deposition. Of course, in some embodiments, the first doped layer 20 can also be formed on the silicon substrate 10 by diffusion. There is no specific limitation here. In this case, the substrate portion below the first doped layer 20 formed by diffusion can be regarded as the silicon substrate 10.

[0044] It should be noted that, in the present invention, the burn-through paste refers to a metal paste with strong burn-through capability, which can be a silver paste or a silver-aluminum paste, etc., and can completely burn through the first passivation film layer 40 so that the first gate electrode 50 can contact the doped layer below the first passivation film layer 40. For example, in one possible embodiment, the glass frit content of the burn-through paste can be higher than that of a traditional paste, thereby providing it with stronger burn-through capability.

[0045] In the present invention, the first electrode setting area 21 is the area on the first doping layer 20 covered by the first gate line electrode 50, and the first predetermined direction is the extension direction of the first gate line electrode 50. When the first gate line electrode 50 is set along the transverse direction of the battery cell, the first predetermined direction is the transverse direction. When the first gate line electrode 50 is set along the longitudinal direction of the battery cell, the first predetermined direction is the longitudinal direction. The setting direction of the first gate line electrode 50 can be selected according to actual specific circumstances and is not limited here.

[0046] Example 2

[0047] Referring to FIG. 5 , in some embodiments, the bifacial solar cell 100 may further include a second doped layer 80, a second passivation film layer 90, and a second gate electrode 110. The second gate electrode 110 is located on the second surface 12. The second doped layer 80 has an opposite polarity to the first doped layer 20. The second doped layer 80 has a plurality of second electrode arrangement regions 81. The second passivation film layer 90 is disposed on the second doped layer 80. The second gate electrode 110 is disposed in the second electrode arrangement regions 81 and is located above the second passivation film layer 90. The second gate electrode 110 at least partially burns through the second passivation film layer 90 to contact the second doped layer 80.

[0048] Specifically, in such an embodiment, the bifacial solar cell 100 is a Topcon solar cell, one of the first doping layer 20 and the second doping layer 80 is a P-type doping layer, and the other is an N-type doping layer, and one of the first gate line electrode 50 and the second gate line electrode 110 is a P-type electrode, and the other is an N-type electrode.

[0049] Furthermore, in some embodiments, the first barrier layer 30 may be a third doping layer having a polarity opposite to that of the first doping layer 20 and the same polarity as that of the second doping layer 80 .

[0050] In some embodiments, the first doping layer 20 can be formed on the first surface 11 by diffusion or deposition, and the second doping layer 80 can also be formed on the second surface 12 by diffusion or deposition. The first barrier layer 30 can be formed by locally removing the coating layer formed on the first doping layer 20 during the formation of the second doping layer 80.

[0051] The following describes in detail the two ways of forming the second doping layer 80:

[0052] The first case: the second doping layer 80 is formed by deposition. In this case, after the first doping layer 20 is formed on the first surface 11, a wrap-around layer with doping properties will be formed on the first doping layer 20 during the deposition of the second doping layer 80. In traditional technical solutions, the wrap-around layer needs to be completely removed in the subsequent process. In the present invention, only the wrap-around layer can be partially removed, that is, the wrap-around layer at the first shielding area 212 is retained, thereby forming the first barrier layer 30 of the present invention. In this case, the first barrier layer 30 includes a third doping layer with the same polarity as the second doping layer 80. It can be understood that when the first doping layer 20 is a P-type doping layer and the second doping layer 80 is an N-type doping layer, the first barrier layer 30 is an N-type doping layer, and when the first doping layer 20 is an N-type doping layer and the second doping layer 80 is a P-type doping layer, the first barrier layer 30 is a P-type doping layer.

[0053] The second case: the second doping layer 80 is formed by diffusion on the second surface 12. In this case, when the first doping layer 20 is a P-type doping layer and the second doping layer 80 is an N-type doping layer, the second doping layer 80 can be formed by phosphorus diffusion on the second surface 12.

[0054] During the process of forming the first doping layer 20, a borosilicate glass film layer will be formed on the surface of the first doping layer 20. When the second doping layer 80 is diffused to form, if the borosilicate glass film layer on the first doping layer 20 is not removed, then a borophosphosilicate glass film layer or a combination layer of the borosilicate glass film layer and the borophosphosilicate glass film layer will be formed on the first doping layer 20. In this case, it is only necessary to remove the borophosphosilicate glass film layer or the combination layer of the borosilicate glass film layer and the borophosphosilicate glass film layer in a local area on the first doping layer 20 to form the first blocking layer 30 on the first blocking area 212. That is, the first blocking layer 30 is a borophosphosilicate glass film layer or a combination layer of the borosilicate glass film layer and the borophosphosilicate glass film layer.

[0055] If the borosilicate glass film layer on the first doping layer 20 is removed before diffusion to form the second doping layer 80, then a phosphosilicate glass film layer will be formed on the first doping layer 20. In this case, it is only necessary to remove the phosphosilicate glass film layer in a local area on the first doping layer 20 to form the first blocking layer 30 on the first blocking area 212, that is, the first blocking layer 30 is a phosphosilicate glass film layer.

[0056] Similarly, when the first doping layer 20 is an N-type doping layer and the second doping layer 80 is a P-type doping layer, the second doping layer 80 can be formed by performing boron diffusion on the second surface 12 .

[0057] During the process of forming the first doping layer 20, a phosphosilicate glass film layer will be formed on the surface of the first doping layer 20. During the process of diffusion to form the second doping layer 80, if the phosphosilicate glass film layer on the first doping layer 20 is not removed, then a borophosphosilicate glass film layer or a combination layer of the phosphosilicate glass film layer and the borophosphosilicate glass film layer will be formed on the first doping layer 20. In this case, it is only necessary to remove the borophosphosilicate glass film layer or the combination layer of the phosphosilicate glass film layer and the borophosphosilicate glass film layer in a local area on the first doping layer 20 to form the first blocking layer 30 on the first shielding area 212. That is, the first blocking layer 30 is a borophosphosilicate glass film layer or a combination layer of the borophosphosilicate glass film layer and the borophosphosilicate glass film layer.

[0058] If the phosphosilicate glass film layer on the first doping layer 20 is removed before the second doping layer 80 is diffused to form the second doping layer 80, then a borosilicate glass film layer will be formed on the first doping layer 20. In this case, it is only necessary to remove the borosilicate glass film layer in a local area on the first doping layer 20 to form the first blocking layer 30 on the first shielding area 212. That is, the first blocking layer 30 is a borosilicate glass film layer.

[0059] Example 4

[0060] In some embodiments, the bifacial solar cell 100 may also be a PERC solar cell, and the first doping layer 20 may be formed on the silicon substrate 10 by diffusion or deposition. In this case, the first barrier layer 30 may be a phosphosilicate glass film layer or a borosilicate glass film layer. For example, when the first doping layer 20 is formed by boron diffusion, the first barrier layer 30 may be a borosilicate glass film layer; when the first doping layer 20 is formed by phosphorus diffusion, the first barrier layer 30 may be a phosphosilicate glass film layer.

[0061] It is easy to understand that, under normal circumstances, during the process of diffusion to form the first doped layer 20, a borosilicate glass film layer or a phosphosilicate glass film layer is formed on the first doped layer 20. After the diffusion is completed, the borosilicate glass film layer or the phosphosilicate glass film layer is usually removed. In the present invention, the first barrier layer 30 can be formed by retaining the borosilicate glass film layer or the phosphosilicate glass film layer in the first shielding area 212 during the removal of the borosilicate glass film layer or the phosphosilicate glass film layer.

[0062] As can be seen from the above, in the present invention, based on the type of the bifacial solar cell 100 and based on the different formation processes of the second doping layer 80, the first barrier layer 30 can be different film layers. That is, in the present invention, the first barrier layer 30 can include at least one of a borosilicate glass film layer, a phosphosilicate glass film layer, a borophosphosilicate glass film layer, and a third doping layer having a polarity opposite to that of the first doping layer 20 and the same polarity as the second doping layer 80.

[0063] Example 5

[0064] Referring to Figures 6 and 7, in some embodiments, the bifacial solar cell 100 may further include a plurality of second barrier layers 120 located on the second electrode setting area 81. The plurality of second barrier layers 120 are stacked on the second doping layer 80 and spaced apart along a second predetermined direction, so that the second electrode setting area 81 includes a second blocking area 812 blocked by the second barrier layers 120 and a second blocking area 811 not blocked by the second barrier layers 120. In this embodiment, the second predetermined direction may be the same as the first predetermined direction.

[0065] Among them, the second gate line electrode 110 is also extended along the second predetermined direction and is located above the second doping layer 80 and the second blocking layer 120. In the second blocking area 812, the second gate line electrode 110 penetrates the second passivation film layer 90 and contacts the second blocking layer 120 and does not contact the second doping layer 80. In the second blocking area 811, the second gate line electrode 110 penetrates the second passivation film layer 90 and contacts the second doping layer 80.

[0066] Thus, by providing the second barrier layer 120, during the fabrication of the second gate electrode 110, the second gate electrode 110 will only burn through the second passivation film 90 in the second shielding region 811 to achieve contact with the second doped layer 80. Meanwhile, in the second shielding region 812, the second gate electrode 110 will only burn through the second passivation film 90 to achieve contact with the second barrier layer 120, without any direct contact with the second doped layer 80. This allows for selective burn-through of the burn-through paste, reduces the metallized contact area between the second gate electrode 110 and the second doped layer 80, and reduces recombination in the metallized area, thereby further improving the conversion efficiency of the bifacial solar cell 100. In such an embodiment, the bifacial solar cell 100 may be a bifacial Topcon solar cell, without limitation herein.

[0067] Specifically, in such an embodiment, the second doping layer 80 can be formed by deposition or diffusion. When the second doping layer 80 is an N-type doping layer, a phosphosilicate glass film layer will be formed on the second doping layer 80 during the process of forming the second doping layer 80. In the subsequent removal process, the phosphosilicate glass film layer at the second blocking area 812 of the second doping layer 80 is retained to form the second blocking layer 120, that is, the second blocking layer 120 is a phosphosilicate glass film layer.

[0068] When the second doping layer 80 is a P-type doping layer, a borosilicate glass film layer will be formed on the second doping layer 80 during the process of forming the second doping layer 80. In the subsequent removal process, the borosilicate glass film layer at the second blocking area 812 of the second doping layer 80 is retained to form the second blocking layer 120, that is, the second blocking layer 120 is a borosilicate glass film layer.

[0069] Example 6

[0070] Referring to FIG. 8 , in some embodiments, a first tunneling layer 60 is disposed between the first doped layer 20 and the first surface 11 .

[0071] In this way, the first tunneling layer 60 can realize the tunneling passivation function on the first surface 11 and enhance the passivation effect of the first surface 11 .

[0072] In some embodiments, a second tunneling layer 130 may be provided between the second doping layer 80 and the second surface 12 . In this way, the second tunneling layer 130 may implement a tunneling passivation function on the second surface 12 and enhance the passivation effect of the second surface 12 .

[0073] Specifically, in such an embodiment, when the bifacial solar cell 100 has only the first tunneling layer 60, the bifacial solar cell 100 is a single-sided Topcon solar cell. When the bifacial solar cell 100 has both the first tunneling layer 60 and the second tunneling layer 130, the bifacial solar cell 100 is a bifacial Topcon solar cell, without limitation herein. The first tunneling layer 60 and the second tunneling layer 130 may both be tunneling silicon oxide films.

[0074] Example 7

[0075] Please refer to Figure 9. In some embodiments, a dielectric layer 70 is provided between the first doped layer 20 and the first barrier layer 30. The first barrier layer 30 is stacked on the dielectric layer 70 and located between the dielectric layer 70 and the first passivation film layer 40. The first barrier layer 30 and the first doped layer 20 are insulated and isolated by the dielectric layer 70.

[0076] Thus, the dielectric layer 70 can insulate and isolate the first barrier layer 30 from the first doped layer 20 , thereby preventing leakage when the first barrier layer 30 is a doped layer with opposite polarity to the first doped layer 20 (ie, the third doped layer mentioned above).

[0077] Further, in such an embodiment, the dielectric layer 70 may include at least one of a borosilicate glass film layer, a phosphosilicate glass film layer, and a borophosphosilicate glass film layer, or a combination of multiple thereof.

[0078] Specifically, in such an embodiment, the bifacial solar cell 100 may be the Topcon solar cell having the second doping layer 80 mentioned above, the first barrier layer 30 is the third doping layer having the same polarity as the second doping layer 80 in the above embodiment, and based on the different processes for forming the second doping layer 80, the dielectric layer 70 is at least one of the borosilicate glass film layer, the phosphosilicate glass film layer, or the borophosphosilicate glass film layer mentioned above.

[0079] For example, when the first doped layer 20 is a P-type doped layer and the second doped layer 80 is an N-type doped layer, a borosilicate glass film layer is formed above the first doped layer 20 during the formation of the first doped layer 20. If the borosilicate glass film layer is not removed and the second doped layer 80 is formed by deposition, a borosilicate glass film layer, a borophosphosilicate glass film layer (both of which constitute the dielectric layer 70), and a first barrier layer 30 (i.e., an N-type doped layer) will be present above the first doped layer 20 in that order. If the borosilicate glass film layer on the first doped layer 20 is removed, a phosphosilicate glass film layer (i.e., the dielectric layer 70) and a first barrier layer 30 (i.e., an N-type doped layer) will be present above the first doped layer 20. Furthermore, when the second doped layer 80 is formed by diffusion, a borosilicate glass film layer (i.e., the dielectric layer 70) and a borophosphosilicate glass film layer (i.e., the first barrier layer 30) will be present in that order above the first doped layer 20.

[0080] When the first doped layer 20 is an N-type doped layer and the second doped layer 80 is a P-type doped layer, a phosphosilicate glass film layer is formed above the first doped layer 20 during the formation of the first doped layer 20. If this phosphosilicate glass film layer is not removed and the second doped layer 80 is formed by deposition, a phosphosilicate glass film layer, a borophosphosilicate glass film layer (both of which constitute the dielectric layer 70), and a first barrier layer 30 (i.e., the P-type doped layer) are sequentially formed above the first doped layer 20. Furthermore, when the second doped layer 80 is formed by diffusion, a phosphosilicate glass film layer (i.e., the dielectric layer 70) and a borophosphosilicate glass film layer (i.e., the first barrier layer 30) are sequentially formed above the first doped layer 20.

[0081] Example 8

[0082] In some embodiments, the first doping layer 20 is a P-type doping layer, and the first barrier layer 30 and the second doping layer 80 are both N-type doping layers.

[0083] In this way, the first barrier layer 30 on the P-type doped layer is an N-type doped layer. By setting the N-type doped layer on the P-type doped layer, the bonding tension between the passivation film layer and the N-type doped layer is greater than the bonding tension between the passivation film layer and the P-type doped layer. When the solder joints are subsequently set, the welding tension of the solder joints during welding can be effectively increased, thereby effectively avoiding the detachment of the solder joints during welding and improving the reliability of welding.

[0084] Specifically, in such an embodiment, the bifacial solar cell 100 is a Topcon solar cell, the first doping layer 20 is a P-type doping layer, the second doping layer 80 is an N-type doping layer, and the first barrier layer 30 is an N-type doping layer after the wrap-around layer formed on the first doping layer 20 when forming the N-type doping layer is partially removed.

[0085] Embodiment 9

[0086] In some embodiments, the bonding tension between the first gate line electrode 50 and the first barrier layer 30 is greater than the bonding tension between the first gate line electrode 50 and the first doping layer 20 .

[0087] In this way, the provision of the first barrier layer 30 can improve the stability of the first gate line electrode 50 and effectively prevent the first gate line electrode 50 from being deflected or falling off.

[0088] Example 10

[0089] In some embodiments, the bonding tension between the first barrier layer 30 and the first passivation film layer 40 is greater than the bonding tension between the first doping layer 20 and the first passivation film layer 40 .

[0090] In this way, the bonding tension between the first barrier layer 30 and the first passivation film layer 40 is relatively large, which can effectively increase the tension of the solder joints provided on the first passivation film layer 40 and prevent the solder joints from falling off during welding.

[0091] Specifically, in such an embodiment, the first doped layer 20 is a P-type doped layer, the first barrier layer 30 is an N-type barrier layer, and the bonding tension between the N-type doped layer and the first passivation film layer 40 is greater than the tension between the P-type doped layer and the first passivation film layer 40.

[0092] Furthermore, in such an embodiment, in some embodiments, the bifacial solar cell 100 further includes a solder joint (not shown) connected to the first grid electrode 50 , and the solder joint is disposed on the first passivation film layer 40 and at least partially above the first barrier layer 30 .

[0093] In this way, disposing the welding spot at least partially above the first barrier layer 30 can increase the welding tension of the welding spot during welding.

[0094] Furthermore, in some embodiments, the solder joint at least partially burns through the first passivation film layer 40 to contact the first barrier layer 30 , and the bonding tension between the solder joint and the first barrier layer 30 is greater than the bonding tension between the solder joint and the first doping layer 20 .

[0095] In this way, the bonding tension between the solder joint and the first barrier layer 30 is relatively large, and the welding tension of the solder joint during welding can also be effectively improved.

[0096] Specifically, in such an embodiment, the solder joint may be a P-type solder joint, and the paste used to form the solder joint may be the same as or different from the paste used to form the first gate line electrode 50 , which is not specifically limited herein.

[0097] Example 11

[0098] In some embodiments, the projection area of ​​the first barrier layer 30 on the silicon substrate 10 is greater than or equal to the projection area of ​​the solder joint on the silicon substrate 10 , and the solder joint is completely located within the projection area of ​​the first barrier layer 30 .

[0099] In this way, the solder joint is completely located in the area where the first barrier layer 30 is located, and the entire area below the solder joint is covered with the first barrier layer 30 . This can maximize the welding tension at the solder joint, thereby ensuring the reliability of the welding.

[0100] Specifically, in such an embodiment, the area of ​​the first barrier layer 30 may preferably be just equal to the projected area of ​​the solder joint or slightly larger than the projected area of ​​the solder joint, which is not specifically limited herein.

[0101] Example 12

[0102] Referring to FIG. 1 , in some embodiments, in the first predetermined direction, a ratio of a length of the first gate line electrode 50 in contact with the first doping layer 20 to a total length of the first gate line electrode 50 is 30%-80%.

[0103] In this way, by setting the contact length between the first gate electrode 50 and the first doped layer 20 within the above-mentioned ratio range, the metallization contact area can be effectively reduced to reduce recombination while avoiding excessive resistance caused by too small a contact area. That is, the relationship between recombination and resistance can be balanced to improve the efficiency of the bifacial solar cell 100.

[0104] Specifically, in such an embodiment, the ratio of the length of the first gate line electrode 50 in contact with the first doping layer 20 to the total length of the first gate line electrode 50 can be, for example, 30%, 40%, 50%, 60%, 70%, 80% or any value between 30% and 80%.

[0105] Furthermore, in such an embodiment, after careful research and derivation by the inventors of the present invention, it was discovered that in order to maximize the balance between metallization recombination and resistance while improving the conversion efficiency of the bifacial solar cell 100 as much as possible, the ratio of the length of the first gridline electrode 50 in contact with the first doping layer 20 to the total length of the first gridline electrode 50 may preferably be in the range of 40%-60%, for example, 40%, 45%, 50%, 55%, 60% and any value between 40%-60%.

[0106] Example 13

[0107] Please refer to Figure 10. In some embodiments, the first surface 11 has a plurality of first regions 111 and second regions 112 alternately arranged in sequence, the first doping layer 20 is arranged on the first region 111 and does not cover the second region 112, and a plurality of first blocking layers 30 are provided above the first doping layer 20 on at least one first region 111.

[0108] In this way, the first doped layer 20 only covers the first area 111 of the first surface 11 and does not cover the second area 112. The first surface 11 of the silicon substrate 10 is not completely covered by the first doped layer 20, which can effectively reduce the parasitic absorption of light by the first doped layer 20 and improve the conversion efficiency.

[0109] Furthermore, in some embodiments, the silicon substrate 10 may preferably be a P-type silicon substrate 10, the first surface 11 is the light-facing surface, the second surface 12 is the backlight surface, the first doping layer 20 is a P-type doping layer, and the second doping layer 80 is an N-type doping layer.

[0110] In this way, on the one hand, a P-type silicon substrate 10 is used, and the preparation technology of the P-type silicon substrate 10 is more mature than that of the N-type substrate; on the other hand, a P-type doping layer that only covers the first area 111 is used on the light-facing surface of the P-type silicon substrate 10. Since the P-type doping layer has a poor passivation effect on the P-type silicon substrate 10, the P-type doping layer is only set on the first area 111 for local passivation, and the second area 112 is directly passivated using the first passivation film layer 40, which has better passivation performance and can improve the passivation effect of the first surface 11, thereby improving the electrical performance of the solar cell and further improving the efficiency.

[0111] In some embodiments, the thickness of the second doping layer 80 is less than the thickness of the first doping layer 20 .

[0112] Thus, when the silicon substrate 10 is a P-type silicon substrate 10 and the first doped layer 20 is a P-type doped layer, setting the thickness of the first doped layer 20 to be thicker can improve the passivation effect of the first surface 11 and thereby enhance the electrical performance of the cell.

[0113] In some embodiments, the first doped layer 20 and the second doped layer 80 may each include a doped semi-insulating polysilicon layer. Thus, the first doped layer 20 and the second doped layer 80 are both made of semi-insulating polysilicon, which has less parasitic absorption than conventional polysilicon. This means that using such a material can reduce parasitic absorption and improve conversion efficiency.

[0114] Example 14

[0115] In some embodiments, the ratio of the area of ​​the first region 111 to the area of ​​the first surface 11 (ie, the area proportion of the first region 111 ) is less than 8%.

[0116] Thus, setting the area ratio of the first region 111 to the first surface 11 within a range of less than 8% can greatly reduce the area proportion of the first doped layer 20 , thereby reducing the parasitic absorption of the first doped layer 20 and improving efficiency.

[0117] At the same time, when the silicon substrate 10 is a P-type silicon substrate 10, the first doped layer 20 is a P-type doped layer, and the first surface 11 is a light-facing surface, the area of ​​the first region 111 is set to be smaller, and the area of ​​the second region 112 can be increased, thereby improving the passivation effect of the first surface 11, that is, the passivation effect of the first surface 11 can be improved while reducing parasitic absorption, thereby improving efficiency.

[0118] Furthermore, in such an embodiment, the ratio of the area of ​​the first region 111 to the area of ​​the first surface 11 is preferably less than 6%, and most preferably less than 5%.

[0119] Example 15

[0120] Continuing to refer to FIG. 10 , in some embodiments, the second surface 12 may have a plurality of third regions 121 and fourth regions 122 alternately disposed in sequence, and the second doped layer 80 is disposed on the third region 121 and does not cover the fourth region 122 .

[0121] Thus, the second doped layer 80 only covers the third region 121 of the second surface 12 and does not cover the fourth region 122. Thus, the second surface 12 of the silicon substrate 10 is not completely covered by the second doped layer 80, which can effectively reduce the parasitic absorption of light by the second doped layer 80 and improve conversion efficiency.

[0122] In some embodiments, the ratio of the area of ​​the third region 121 to the area of ​​the second surface 12 is greater than or equal to 30% and less than 100%.

[0123] In this way, when the silicon substrate 10 is a P-type silicon substrate 10, the second doped layer 80 is an N-type doped layer, and the second surface 12 is a backlight surface, the area of ​​the third region 121 of the second surface 12 is set to be larger, which can ensure the area ratio of the N-type doped layer while reducing parasitic absorption, balance the passivation contact area and parasitic absorption, and thus improve the conversion efficiency.

[0124] Further, in such an embodiment, the ratio of the area of ​​the third region 121 to the area of ​​the second surface 12 is preferably greater than or equal to 40% and less than 100%. Further, in such an embodiment, the ratio of the area of ​​the third region 121 to the area of ​​the second surface 12 is more preferably greater than or equal to 50% and less than 100%, and most preferably greater than or equal to 60% and less than 100%.

[0125] Throughout this specification, references to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" indicate that a specific feature, structure, material, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative uses of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0126] In addition, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A double-sided solar cell, characterized in that: include: A silicon substrate having a first surface and a second surface opposite to each other; A first doping layer located on the first surface, wherein the first doping layer has a plurality of first electrode arrangement regions; A plurality of first blocking layers located on the first electrode arrangement region, wherein the plurality of first blocking layers are arranged in an interval along a first predetermined direction, so that the first electrode arrangement region includes a first blocking region blocked by the first blocking layers and a first non-blocking region not blocked by the first blocking layers; a first passivation film layer, wherein the first passivation film layer covers the first barrier layer and the first doping layer; A first gate line electrode extending along the first predetermined direction, the first gate line electrode being arranged in the first electrode arrangement region and being located above the first doping layer and the first barrier layer, the first gate line electrode being made of a burn-through paste; Among them, in the first blocking area, the first gate line electrode penetrates the first passivation film layer and contacts the first blocking layer but does not contact the first doping layer. In the first non-blocking area, the first gate line electrode penetrates the first passivation film layer and contacts the first doping layer.

2. The double-sided solar cell according to claim 1, characterized in that: A first tunneling layer is disposed between the first doping layer and the first surface.

3. The double-sided solar cell according to claim 1, characterized in that: A dielectric layer is provided between the first doping layer and the first barrier layer. The first barrier layer is stacked on the dielectric layer and located between the dielectric layer and the first passivation film layer. The first barrier layer and the first doping layer are insulated and isolated by the dielectric layer.

4. The double-sided solar cell according to claim 3, characterized in that: The dielectric layer includes at least one of a borosilicate glass film layer, a phosphosilicate glass film layer and a borophosphosilicate glass film layer, or a combination of multiple thereof.

5. The double-sided solar cell according to claim 1, characterized in that: The first barrier layer includes at least one of a borosilicate glass film layer, a phosphosilicate glass film layer, a borophosphosilicate glass film layer and a third doping layer, wherein the third doping layer has a polarity opposite to that of the first doping layer.

6. The double-sided solar cell according to claim 1, characterized in that: The first doping layer is a P-type doping layer, and the first barrier layer is an N-type doping layer.

7. The double-sided solar cell according to claim 1, characterized in that: A bonding tension between the first gate line electrode and the first barrier layer is greater than a bonding tension between the first gate line electrode and the first doping layer.

8. The double-sided solar cell according to claim 1, characterized in that: The bonding tension between the first barrier layer and the first passivation film layer is greater than the bonding tension between the first doping layer and the first passivation film layer.

9. The double-sided solar cell according to claim 8, characterized in that: The double-sided solar cell sheet further includes a welding point connected to the first grid line electrode, wherein the welding point is arranged on the first passivation film layer and at least partially located above the first barrier layer.

10. The double-sided solar cell according to claim 9, characterized in that: The solder joint at least partially burns through the first passivation film layer and contacts the first barrier layer, and the bonding tension between the solder joint and the first barrier layer is greater than the bonding tension between the solder joint and the first doping layer.

11. The double-sided solar cell according to claim 9, characterized in that: The projection area of ​​the first barrier layer on the silicon substrate is greater than or equal to the projection area of ​​the solder joint on the silicon substrate, and the solder joint is completely located within the projection area of ​​the first barrier layer.

12. The double-sided solar cell according to claim 1, characterized in that: In the first predetermined direction, a ratio of a length of the first gate line electrode in contact with the first doping layer to a total length of the first gate line electrode is 30%-80%.

13. The double-sided solar cell according to claim 12, characterized in that: In the first predetermined direction, a ratio of a length of the first gate line electrode in contact with the first doping layer to a total length of the first gate line electrode is 40%-60%.

14. The double-sided solar cell according to claim 1, characterized in that: The first surface has a plurality of first regions and second regions alternately arranged in sequence, the first doping layer is arranged on the first region and does not cover the second region, and a plurality of first blocking layers are arranged above the first doping layer on at least one of the first regions.

15. The double-sided solar cell according to claim 14, characterized in that: A ratio of an area of ​​the first region to an area of ​​the first surface is less than 8%.

16. The double-sided solar cell according to any one of claims 1 to 15, characterized in that: The double-sided solar cell sheet further comprises: a second doping layer located on the second surface, the second doping layer having a polarity opposite to that of the first doping layer, and the second doping layer having a plurality of second electrode arrangement regions; A second passivation film layer, the second passivation film layer is disposed on the second doping layer; and The second gate line electrode is arranged in the second electrode arrangement region and located on the second doping layer, and the second gate line electrode at least partially burns through the second passivation film layer and contacts the second doping layer.

17. The double-sided solar cell according to claim 16, characterized in that: The bifacial solar cell sheet further includes a plurality of second barrier layers located on the second electrode arrangement region, wherein the plurality of second barrier layers are stacked on the second doping layer and spaced apart along a second predetermined direction, so that the second electrode arrangement region includes a second shielding region shielded by the second barrier layers and a second non-shielding region not shielded by the second barrier layers; Among them, the second gate line electrode is extended along the second predetermined direction and is located above the second doped layer and the second blocking layer. In the second shielding area, the second gate line electrode penetrates the second passivation film layer and contacts the second blocking layer but does not contact the second doped layer. In the second non-shielding area, the second gate line electrode penetrates the second passivation film layer and contacts the second doped layer.

18. The double-sided solar cell according to claim 17, characterized in that: The second doping layer is a borosilicate glass film layer or a phosphosilicate glass film layer.

19. The double-sided solar cell according to claim 17, characterized in that: A second tunneling layer is disposed between the second doping layer and the second surface.

20. The double-sided solar cell according to claim 16, characterized in that: The second surface has a plurality of third regions and fourth regions which are alternately arranged in sequence, and the second doping layer is arranged on the third regions and does not cover the fourth regions.

21. The double-sided solar cell according to claim 20, characterized in that: A ratio of an area of ​​the third region to an area of ​​the second surface is greater than or equal to 30% and less than 100%.

22. A battery assembly, characterized in that: A double-sided solar cell comprising any one of several claims 1-21.

23. A photovoltaic system, characterized in that: A battery assembly comprising the battery assembly of claim 22.

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