Solar cell, solar module, and photovoltaic system

Abstract

The present application is applicable to the technical field of solar cells, and provides a solar cell, a solar module, and a photovoltaic system. In the solar cell, a P-type doped layer and an N-type doped layer are provided on a first surface of a silicon wafer, and the thickness of a passivation film layer on at least part of the N-type doped layer is greater than the thickness of the passivation film layer on at least part of the P-type doped layer. In this way, by means of coordinated optimization design of different thicknesses of the passivation film layer on at least part of the N-type doped layer and at least part of the P-type doped layer, and by making the passivation film layer on at least part of the N-type doped layer have a greater thickness, passivation effects of different doped regions of the solar cell can be better matched, thereby improving the performance of the solar cell, saving material usage, and reducing costs.

Description

Solar cell, cell module and photovoltaic system

[0001] Cross-reference to Related Applications

[0002] The present disclosure claims priority to the Chinese patent application No. 202411000880.2, filed on July 24, 2024, entitled “Solar cell, cell module and photovoltaic system”, the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] The present disclosure relates to the technical field of solar cell, and in particular to a solar cell, a cell module and a photovoltaic system. BACKGROUND

[0004] Solar cell power generation is a sustainable clean energy source, which can convert sunlight into electrical energy by using the photovoltaic effect of semiconductor p-n junction. In a solar cell, a P-type doped layer and an N-type doped layer are provided on a silicon wafer, and a passivation film layer is provided on each of the doped layers to passivate the cell.

[0005] In the current solar cell, the cooperation between the passivation film layers on the P-type doped layer and the N-type doped layer is not fully considered, so as to improve the passivation effect. Therefore, the performance of the current solar cell is poor. SUMMARY

[0006] The present disclosure provides a solar cell, a cell module and a photovoltaic system.

[0007] The present disclosure is implemented in this way. The solar cell of the present disclosure comprises:

[0008] a silicon wafer having opposite first and second surfaces;

[0009] a P-type doped layer and an N-type doped layer provided on the first surface of the silicon wafer; and

[0010] a passivation film layer provided on each of the P-type doped layer and the N-type doped layer; wherein the passivation film layer on at least a partial region of the N-type doped layer has a first thickness, and the passivation film layer on at least a partial region of the P-type doped layer has a second thickness, the first thickness being greater than the second thickness.

[0011] In some embodiments, the first surface has an edge region and a middle region, the middle region being located inward of the edge region, the edge region being closer to the edge of the first surface than the middle region.

[0012] The part of the N-type doped layer on the middle region is a first N-type doped part, the passivation film layer on the first N-type doped part has the first thickness, the part of the P-type doped layer on the middle region is a first P-type doped part, and the passivation film layer on the first P-type doped part has the second thickness.

[0013] In some embodiments, the part of the N-type doped layer on the edge region is a second N-type doped part, the passivation film layer on the second N-type doped part has a third thickness, the part of the P-type doped layer on the edge region is a second P-type doped part, and the passivation film layer on the second P-type doped part has a fourth thickness, the third thickness is greater than the first thickness, and the fourth thickness is greater than the second thickness.

[0014] In some embodiments, the third thickness is greater than the fourth thickness.

[0015] In some embodiments, the passivation film layer covering the middle region is a one-piece continuous structure.

[0016] In some embodiments, the ratio of the first thickness to the second thickness is greater than 1 and less than or equal to 2.

[0017] In some embodiments, the ratio of the first thickness to the second thickness is 1.025-1.6.

[0018] In some embodiments, the difference between the first thickness and the second thickness is 2nm-50nm.

[0019] In some embodiments, the difference between the first thickness and the second thickness is 5nm-30nm.

[0020] In some embodiments, the first thickness is 52nm-250nm, and the second thickness is 50nm-200nm.

[0021] In some embodiments, the first thickness is 55nm-230nm, and the second thickness is 50nm-200nm.

[0022] In some embodiments, on the middle region, there is a spacing region between adjacent P-type doped layers and N-type doped layers, the passivation film layer also covers the spacing region, the part of the passivation film layer on the spacing region has a fifth thickness, and the second thickness is greater than the fifth thickness.

[0023] In some embodiments, on the intermediate region, the passivation film layer on the P-type doped layer, the passivation film layer on the N-type doped layer and the passivation film layer at the interval region are in an integrated continuous structure.

[0024] In some embodiments, the ratio of the second thickness to the third thickness is greater than 1 and less than or equal to 2.

[0025] In some embodiments, the ratio of the second thickness to the third thickness is 1.1-1.8.

[0026] In some embodiments, the difference between the second thickness and the third thickness is 2nm-50nm.

[0027] In some embodiments, the difference between the second thickness and the third thickness is 20nm-40nm.

[0028] In some embodiments, the second thickness is 50nm-200nm and the third thickness is 48nm-150nm.

[0029] In some embodiments, the second thickness is 50nm-200nm and the third thickness is 30nm-160nm.

[0030] In some embodiments, the resistivity of the silicon wafer is greater than 20ohm.cm, and the difference between the second thickness and the third thickness is 10nm-60nm.

[0031] In some embodiments, the interval region is a trench formed on the first surface, the passivation film layer covers the side and bottom of the trench, and the thickness of at least part of the passivation film layer on the side of the trench is greater than the thickness of the passivation film layer on the bottom of the trench.

[0032] In some embodiments, the solar cell further satisfies at least one of the following:

[0033] The N-type doped layer has a first extension part extending to and overhanging above the trench, and the passivation film layer is on the end of the first extension part and the surface of the first extension part towards the trench, wherein the thickness of the passivation film layer on the surface of the first extension part towards the trench is greater than the thickness of the passivation film layer on the bottom of the trench.

[0034] The P-type doped layer has a second extension part extending over and hanging over the trench, the end of the second extension part and the surface of the second extension part towards the trench are both provided with the passivation film layer, wherein the thickness of the passivation film layer on the surface of the second extension part towards the trench is greater than the thickness of the passivation film layer on the bottom surface of the trench.

[0035] In some embodiments, the spacing region is a protrusion between the adjacent P-type doped layer and N-type doped layer, the top surface of the protrusion is higher than the top of the P-type doped layer and N-type doped layer, the top surface and side surface of the protrusion are both provided with the passivation film layer, and the thickness of the passivation film layer on the top surface of the protrusion is greater than the thickness of the passivation film layer on the side surface of the protrusion.

[0036] In some embodiments, the part of the passivation film layer on the intermediate region comprises a first type of passivation sub-layer and a second type of passivation sub-layer stacked, and the thickness of the passivation film layer on the intermediate region is the sum of the thicknesses of the first type of passivation sub-layer and the second type of passivation sub-layer.

[0037] The thickness of the part of the first type of passivation sub-layer on the N-type doped layer is greater than the thickness of the part of the first type of passivation sub-layer on the P-type doped layer.

[0038] In some embodiments, the thickness of the part of the second type of passivation sub-layer on the N-type doped layer is equal to the thickness of the part of the second type of passivation sub-layer on the P-type doped layer.

[0039] In some embodiments, the first type of passivation sub-layer is prepared by a PECVD process or a thermal growth process, and the second type of passivation sub-layer is prepared by an atomic deposition process.

[0040] In some embodiments, the first type of passivation sub-layer comprises at least one of a silicon oxide film layer and a silicon nitride film layer, and the second type of passivation sub-layer comprises an aluminum oxide film layer.

[0041] In some embodiments, the silicon oxide film layer is a plurality of layers of silicon oxide stacked in sequence, the silicon nitride film layer is a plurality of layers of silicon nitride stacked in sequence, and the silicon oxynitride film layer is a plurality of layers of silicon oxynitride stacked in sequence.

[0042] The present disclosure also provides a battery assembly comprising a plurality of the solar cell pieces according to any one of the above.

[0043] The present disclosure also provides a photovoltaic system comprising the battery assembly according to the above.

[0044] In the solar cell sheet, the cell assembly and the photovoltaic system provided in the embodiments of the present disclosure, the P-type doped layer and the N-type doped layer are arranged on the first surface of the silicon sheet, and the thickness of the passivation film layer on at least part of the N-type doped layer is greater than the thickness of the passivation film layer on at least part of the P-type doped layer. In this way, by optimizing the thickness of the passivation film layer on at least part of the N-type doped layer and at least part of the P-type doped layer, and by making the thickness of the passivation film layer on at least part of the N-type doped layer greater, the passivation effect of different doped regions of the solar cell can be optimized, so as to improve the performance of the solar cell sheet, and meanwhile, the use of materials can be saved and the cost can be reduced.

[0045] Additional aspects and advantages of the present disclosure will be made apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0046] FIG. 1 is a schematic diagram of a module of a photovoltaic system according to an embodiment of the present disclosure;

[0047] FIG. 2 is a schematic diagram of a cross-sectional structure of a solar cell sheet according to an embodiment of the present disclosure;

[0048] FIG. 3 is a schematic diagram of a planar structure of a partial structure of a solar cell sheet according to an embodiment of the present disclosure;

[0049] FIG. 4 is a schematic diagram of a cross-sectional structure of a solar cell sheet in a middle region according to an embodiment of the present disclosure;

[0050] FIG. 5 is a schematic diagram of a structure of a passivation film layer according to an embodiment of the present disclosure;

[0051] FIG. 6 is another schematic diagram of a cross-sectional structure of a solar cell sheet in a middle region according to an embodiment of the present disclosure;

[0052] FIG. 7 is still another schematic diagram of a cross-sectional structure of a solar cell sheet in a middle region according to an embodiment of the present disclosure;

[0053] FIG. 8 is yet another schematic diagram of a cross-sectional structure of a solar cell sheet in a middle region according to an embodiment of the present disclosure;

[0054] FIG. 9 is still yet another schematic diagram of a cross-sectional structure of a solar cell sheet in a middle region according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0055] In order to make the purposes, technical solutions, and advantages of the present disclosure clearer, the present disclosure will be further described in detail below with reference to the drawings and embodiments. The examples of the embodiments are shown in the drawings, in which the same or similar notations denote the same or similar elements or elements having the same or similar functions throughout. It should be noted that the embodiments described below with reference to the drawings are exemplary and are only used to explain the present disclosure, and should not be understood as limiting the present disclosure. In addition, it should be understood that the specific embodiments described herein are only used to explain the present disclosure and should not be used to limit the present disclosure.

[0056] In the description of the present disclosure, it should be understood that the terms "upper", "lower", "left", "right", "top", "bottom", "side", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present disclosure.

[0057] In addition, the terms "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the present disclosure, the meaning of "several" is two or more, unless otherwise explicitly specified and limited.

[0058] In the present disclosure, unless otherwise explicitly specified and limited, the "on" or "under" of the first feature to the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the "on", "above", and "above" of the first feature to the second feature include that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The "under", "below", and "below" of the first feature to the second feature include that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0059] The disclosure below provides many different embodiments or examples for implementing different structures of the disclosure. For the sake of brevity and clarity, descriptions of all possible combinations are not provided in this disclosure, only certain examples are described. Of course, it is appreciated that all possible combinations are within the scope of the disclosure. Furthermore, the disclosure provides examples of various specific processes and materials, but one of ordinary skill in the art will appreciate that other processes and / or materials can be used.

[0060] Referring to FIG. 1, the photovoltaic system 1000 in the embodiment of the disclosure can include the battery assembly 200 in the embodiment of the disclosure, and the battery assembly 200 in the embodiment of the disclosure can include a plurality of solar cell pieces 100 in the embodiment of the disclosure. The plurality of solar cell pieces 100 can be connected together by a solder strip to form a plurality of cell strings, and each cell string can form the battery assembly 200 by series connection, parallel connection, or series-parallel connection.

[0061] Referring to FIG. 2, the solar cell piece 100 in the embodiment of the disclosure can include a silicon wafer 10, a P-type doped layer 20, an N-type doped layer 30, and a passivation film layer 40.

[0062] The silicon wafer 10 has a first surface 11 and a second surface 12 opposite to each other, and the P-type doped layer 20 and the N-type doped layer 30 are arranged on the first surface 11 of the silicon wafer 10. The passivation film layer 40 covers the first surface 11, and the P-type doped layer 20 and the N-type doped layer 30 are both arranged with the passivation film layer 40.

[0063] As shown in FIG. 2, the passivation film layer 40 on at least a part of the N-type doped layer 30 has a first thickness D1, and the passivation film layer 40 on at least a part of the P-type doped layer 20 has a second thickness D2, and the first thickness D1 is greater than the second thickness D2.

[0064] In the solar cell sheet 100, the cell assembly 200 and the photovoltaic system 1000 in the embodiments of the present disclosure, the P-type doped layer 20 and the N-type doped layer 30 are arranged on the first surface 11 of the silicon sheet 10, and the thickness of the passivation film layer 40 on at least part of the N-type doped layer 30 is greater than the thickness of the passivation film layer 40 on at least part of the P-type doped layer 20, that is, the first thickness D1 is greater than the second thickness D2. In this way, by optimizing the design of the passivation film layer 40 on at least part of the N-type doped layer 30 and at least part of the P-type doped layer 20 with different thicknesses, and the thickness of the passivation film layer 40 on at least part of the N-type doped layer 30 being thicker, the passivation effect of different doped regions of the solar cell 100 can be optimized to achieve a better matching effect, thereby improving the performance of the solar cell sheet 100, while also saving material use and reducing costs.

[0065] Specifically, in the embodiments of the present disclosure, the first surface 11 can be the back surface of the silicon sheet 10, and the second surface 12 can be the front surface of the silicon sheet 10. The solar cell sheet 100 is preferably a back contact solar cell sheet. Of course, in some embodiments, the solar cell sheet 100 can also be other types of cell sheets having both P-type doped layer 20 and N-type doped layer 30 on the same surface, which is not limited here.

[0066] The silicon sheet 10 can be a P-type silicon sheet or an N-type silicon sheet, which is not limited here. The P-type doped layer 20 can be a P-type doped polysilicon layer, a P-type doped microcrystalline silicon layer, etc., and the N-type doped layer 30 can be an N-type doped polysilicon layer, an N-type doped microcrystalline silicon layer, etc., which is not limited here. The P-type doped layer 20 and the N-type doped layer 30 can be prepared by diffusion, deposition, etc., which is not limited here.

[0067] It should be noted that in the present disclosure, the thickness of the passivation film layer 40 on the N-type doped layer 30 refers to the thickness of the passivation film layer 40 on all surfaces of the N-type doped layer 30 covered by the passivation film layer 40, and similarly, the thickness of the passivation film layer 40 on the P-type doped layer 20 refers to the thickness of the passivation film layer 40 on all surfaces of the P-type doped layer 20 covered by the passivation film layer 40.

[0068] In addition, in this document, a certain film layer covering a certain surface or a certain film layer can be that the film layer is directly stacked on the surface or the certain film layer, or that there is another film layer between the film layer and the surface or the film layer, and the covering only means to define the specific arrangement range of the film layer.

[0069] It can be understood that in the back contact solar cell, the first surface 11 has a plurality of P-type doped layers 20 and a plurality of N-type doped layers 30, and the plurality of P-type doped layers 20 and the plurality of N-type doped layers 30 are arranged alternately in sequence. In addition, it can be understood that in the back contact solar cell, a tunneling layer (not shown) can also be arranged between the P-type doped layer 20 and the N-type doped layer 30 and the silicon wafer 10.

[0070] Please refer to FIG. 2 and FIG. 4, in some embodiments, the first surface 11 has an edge region 111 and a middle region 112, the middle region 111 is located inside the edge region 112, and the edge region 111 is closer to the edge of the first surface 11 than the middle region 112.

[0071] In the above embodiments, the passivation film layer 40 on the portion of the middle region 112 has a first thickness D1, and the passivation film layer 40 on the portion of the P-type doped layer 20 has a second thickness D2.

[0072] In this way, the passivation effect of the area corresponding to the N-type doped layer 30 and the P-type doped layer 20 at the middle region 112 position can be optimized, thereby improving the performance of the solar cell 100.

[0073] Specifically, as shown in FIG. 2, in such embodiments, the silicon wafer 10 further includes a plurality of side surfaces 13 connecting the first surface 11 and the second surface 12, the edge region 111 is located at the edge position where the first surface 11 and the side surface 13 meet, and the middle region 112 is located at the middle position of the first surface 11, and the edge region 111 is located between the middle region 112 and the side surface 13.

[0074] As shown in FIG. 2, the "edge region 111" refers to the region adjacent to the edge where the first surface 11 and the side surface 13 meet, and the "middle region 112" refers to the region of the first surface 11 other than the edge region 111.

[0075] As shown in FIG. 3 (the passivation film layer 40 is not shown in FIG. 3), in some embodiments, the specific arrangement of the middle region 112 and the edge region 111 can be as shown in FIG. 3, in such embodiments, the edge region 111 can be arranged around the middle region, that is, the edge of the first surface 11 has the edge region 111 at the junction with all the side surfaces 13, and the middle region 112 is located inside the edge region 110, that is, the edge region 111 is the region located at the edge position of the first surface 11.

[0076] Of course, in some embodiments, there can also be no edge region at the edge where the first surface 11 meets the side surface 13, for example, in one possible embodiment, after cutting is completed, a cutting surface is formed on the half-cell, the cutting surface is also the side surface 13, in such a case, the edge where the first surface 11 meets the cutting surface has no edge region 110, while the edge regions 110 are present around the other edges.

[0077] Referring to FIG. 2, in some embodiments, the passivation film layer 40 on the portion of the edge region 111 where the N-type doped layer 30 is located has a third thickness D3, and the passivation film layer 40 on the portion of the edge region 111 where the P-type doped layer 20 is located has a fourth thickness D4, the third thickness D3 is greater than the first thickness D1, and the fourth thickness D4 is greater than the second thickness D2.

[0078] In this way, by setting the thickness of the passivation film layer on the doped layer on the edge region 111 to be thicker, the passivation effect of the edge region 111 can be improved, the edge recombination can be reduced, and the efficiency of the solar cell 100 can be further improved.

[0079] Further, in such embodiments, the third thickness D3 can be greater than the fourth thickness D4. In this way, by optimizing the design of the passivation film layer 40 on the N-type doped layer 30 and the P-type doped layer 20 of the edge region 111 with different thicknesses, and the thickness of the passivation film layer 40 on the N-type doped layer 30 being thicker, the passivation effect of the edge region 11 can be optimized.

[0080] In some embodiments, the passivation film layer 40 covering the middle region 112 is a one-piece continuous structure.

[0081] In this way, the passivation film layer 40 on this portion can be prepared in one time by PECVD process, and in the preparation process, different thicknesses of different regions can be achieved by controlling the electrical conductivity of different regions.

[0082] Specifically, in this document, the "one-piece continuous structure" refers to the fact that the material and structure of the passivation film layer 40 on each portion are the same, and the passivation film layer 40 on each portion is a whole layer of continuous film prepared by one process, only the thicknesses of different regions are different. In the following, if the same description appears, please refer to this treatment.

[0083] It can be understood that in the solar cell 100, the metal electrode also penetrates the passivation film layer 40 and contacts the doped layer, that is, in the subsequent preparation process, the passivation film layer 40 at the position corresponding to the metal electrode is removed or ablated when the metal electrode is made. Specifically, in the back contact solar cell, the P-type electrode and the N-type electrode (not shown in the figure) are provided, the P-type electrode penetrates the passivation film layer 40 and contacts the P-type doped layer 20, and the N-type electrode penetrates the passivation layer 20 and contacts the N-type doped layer 13.

[0084] Referring to FIG. 5, in some embodiments, the passivation film layer 40 located at the part of the middle region 112 can include the first type passivation sub-layer 41 and the second type passivation sub-layer 42 arranged in a stack, and the thickness of the passivation film layer 40 located at the middle region 112 is the sum of the thicknesses of the first type passivation sub-layer 41 and the second type passivation sub-layer 42.

[0085] In the above embodiment, the thickness of the first type passivation sub-layer 41 located on the N-type doped layer 30 is greater than the thickness of the first type passivation sub-layer 41 located on the P-type doped layer 20.

[0086] In this way, on the one hand, the passivation film layer 40 on the middle region 112 adopts the structure of different types of passivation sub-layers, which can improve the passivation effect, and on the other hand, by setting the thickness of the first type passivation sub-layer 41 located on the N-type doped layer 30 to be greater than the thickness of the first type passivation sub-layer 41 located on the P-type doped layer 20, the thickness of the passivation film layer 40 on the middle region 112 located on the N-type doped layer 30 can be greater than the thickness of the passivation film layer 40 on the middle region 112 located on the P-type doped layer 20.

[0087] Further, in such embodiments, the thickness of the second type passivation sub-layer 42 located on the N-type doped layer 30 is equal to the thickness of the second type passivation sub-layer 42 located on the P-type doped layer 20.

[0088] In some embodiments, the first type passivation sub-layer 41 is prepared by a PECVD process or a thermal growth process, and the second type passivation sub-layer 42 is prepared by an atomic deposition process.

[0089] Specifically, in the embodiments of the present disclosure, the first type passivation sub-layer 41 can include at least one of a silicon oxide film layer, a silicon nitride film layer, and a silicon oxynitride film layer, and the second type passivation sub-layer 42 can include an aluminum oxide film layer. As shown in FIG. 4,

[0090] As shown in FIG. 5, in some embodiments, the passivation film layer 40 on the intermediate region 112 can adopt a three-layer stacked structure of a silicon oxide film layer 401, an aluminum oxide film layer 402, and a silicon nitride film layer 403, the thickness of the aluminum oxide film layer 401 on the P-type doped layer 20 and the N-type doped layer 30 can be substantially the same, the thickness of the silicon oxide film layer 401 on the N-type doped layer 30 can be greater than the thickness of the silicon oxide film layer 401 on the P-type doped layer 20, and the thickness of the silicon nitride film layer 403 on the N-type doped layer 30 can be greater than the thickness of the silicon nitride film layer 403 on the P-type doped layer 20.

[0091] Of course, in some embodiments, the passivation film layer 40 on the intermediate region 112 can also adopt a two-layer stacked structure of only the aluminum oxide film layer 402 and the silicon nitride film layer 403, the thickness of the aluminum oxide film layer 401 on the P-type doped layer 20 and the N-type doped layer 30 can be substantially the same, and the thickness of the silicon nitride film layer 403 on the N-type doped layer 30 can be greater than the thickness of the silicon nitride film layer 403 on the P-type doped layer 20.

[0092] In addition, it should be noted that, in some embodiments, the silicon nitride film layer 403 can be a single-layer film structure or a multi-layer film structure composed of multiple layers of silicon nitride layers with different refractive indexes, which is not limited here.

[0093] In addition, in some embodiments, in the solar cell wafer 100, the silicon oxide film layer can be a plurality of silicon oxide layers stacked in sequence, the silicon nitride film layer can be a plurality of silicon nitride layers stacked in sequence, and the silicon oxynitride film layer can be a plurality of silicon oxynitride layers stacked in sequence. That is, in some possible embodiments, the silicon oxide film layer, the silicon nitride film layer, and the silicon oxynitride film layer can all be multi-layer structures.

[0094] In some embodiments, the ratio of the first thickness D1 to the second thickness D2 is greater than 1 and less than or equal to 2, that is, 1 < D1 / D2 ≤ 2.

[0095] In this way, the passivation film layer 40 on the N-type doped layer 30 on the intermediate region 112 has a greater thickness, which can improve the passivation effect of the corresponding region of the N-type doped layer 30, so that the passivation effects of the corresponding regions of the P-type doped layer 20 and the N-type doped layer 30 achieve a relatively optimal matching effect, thereby improving the performance of the solar cell wafer 100.

[0096] Specifically, in such embodiments, the ratio of the first thickness D1 to the second thickness D2 can be, for example, 1.01, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.55, 1.6, 1.65, 1.7, 1.75, 1.8, 1.85, 1.9, 1.95, 2, or any value greater than 1 and less than or equal to 2, which is not limited here.

[0097] In some embodiments, the ratio of the first thickness D1 to the second thickness D2 can preferably be in the range of 1.025-1.6. Through repeated research and verification by the inventors of the present disclosure, it is found that setting the ratio of the first thickness D1 to the second thickness D2 in this preferred range can make the passivation effect of the regions corresponding to the P-type doped layer 20 and the N-type doped layer 30 reach the optimal matching effect while keeping the cost relatively low.

[0098] Specifically, in such embodiments, the preferred ratio of the first thickness D1 to the second thickness D2 can be, for example, 1.025, 1.03, 1.04, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.55, 1.6, or any value in the range of 1.025-1.6.

[0099] In some embodiments, the difference between the first thickness D1 and the second thickness D2 can be in the range of 2nm-50nm. In this way, by reasonably designing the difference between the two thicknesses, the passivation effect of the regions corresponding to the P-type doped layer 20 and the N-type doped layer 30 can reach a relatively optimal matching effect, thereby improving the performance of the solar cell 100.

[0100] In such embodiments, the difference between the first thickness D1 and the second thickness D2 can preferably be in the range of 5nm-30nm. Through repeated research and verification by the inventors of the present disclosure, it is found that setting the difference between the first thickness D1 and the second thickness D2 in this preferred range can make the passivation effect of the regions corresponding to the P-type doped layer 20 and the N-type doped layer 30 reach the optimal matching effect while keeping the cost relatively low.

[0101] Specifically, in such embodiments, the difference between the first thickness D1 and the second thickness D2 can preferably be in the range of 5nm, 7nm, 9nm, 10nm, 12nm, 14nm, 16nm, 18nm, 20nm, 22nm, 24nm, 26nm, 28nm, 30nm, or any value in the range of 5nm-30nm.

[0102] In some embodiments, the first thickness D1 can be in the range of 52nm-250nm, and the second thickness D2 can be in the range of 50nm-200nm. In this way, setting the first thickness D1 and the second thickness D2 in the above ranges can make the passivation film layer 40 achieve good passivation effect while keeping the cost low.

[0103] In such embodiments, the first thickness D1 can be preferably 55nm-230nm, and the second thickness D2 can be 50nm-200nm. Through repeated research and verification by the inventors of the present disclosure, it is found that by setting the sizes of the first thickness D1 and the second thickness D2 in this preferred range, the passivation effects of the corresponding regions of the P-type doped layer 20 and the N-type doped layer 30 can be optimally matched, and the cost can also be relatively low.

[0104] In a preferred embodiment, the first thickness D1 is preferably 55nm-230nm, the second thickness D2 is preferably 50nm-200nm, the difference between the first thickness D1 and the second thickness D2 is preferably 5nm-30nm, and the ratio of the first thickness D1 to the second thickness D2 is preferably 1.025-1.6. In this way, the passivation effects of the corresponding regions of the P-type doped layer 20 and the N-type doped layer 30 can be optimally matched, and the cost can also be relatively low.

[0105] Referring to FIG. 4, in some embodiments, the solar cell 100 is a back contact solar cell, and in such cases, on the middle region 112, there is a spacing region 120 between the adjacent P-type doped layer 20 and N-type doped layer 30, and the passivation film layer 40 also covers the spacing region 120, and the part of the passivation film layer 40 at the spacing region 120 has a fifth thickness D5, wherein the first thickness D1 is greater than the second thickness D2, and the second thickness D2 is greater than the fifth thickness D5.

[0106] In this way, by reasonably optimizing the thicknesses of the N-type doped layer 30, the P-type doped layer 20, and the passivation film layer 40 on the spacing region 120 between the N-type doped layer 30 and the P-type doped layer 20 on the middle region 112, the passivation effects of the corresponding regions can be well matched, and the electrical performance of the solar cell 100 can be improved at a relatively low cost.

[0107] In such embodiments, on the middle region 112, the passivation film layer 40 on the P-type doped layer 20, the passivation film layer 40 on the N-type doped layer 30, and the passivation film layer 40 at the spacing region 120 are in an integrated and continuous structure. In this way, they can be directly prepared at one time through the PECVD process, and during the preparation process, different thicknesses of different regions can be achieved by controlling the electrical conductivity of different regions.

[0108] Further, in some embodiments, the ratio of the second thickness D2 to the fifth thickness D5 can be greater than 1 and less than 2, i.e., 1

[0109] By designing the thicknesses of the fifth thickness D5, the second thickness D2, and the first thickness D1 to gradually increase in the above proportions, the passivation effect of the entire solar cell 100 can achieve a better matching effect, thereby improving the performance of the solar cell 100, while also keeping the cost relatively low.

[0110] Specifically, in such embodiments, the ratio of the second thickness D2 to the fifth thickness D5 can be, for example, 1.01, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.55, 1.6, 1.65, 1.7, 1.75, 1.8, 1.85, 1.9, 1.95, 2, or any value greater than 1 and less than or equal to 2, without any specific limitation herein.

[0111] In some embodiments, in the back-contact solar cell, the ratio of the second thickness D2 to the fifth thickness D5 is preferably 1.1-1.8. Through repeated research and verification, the inventors of this disclosure have discovered that setting the ratio of the second thickness D2 to the fifth thickness D5 within this preferred range allows for optimal matching of the passivation effects of the corresponding regions of the P-type doped layer 20, the N-type doped layer 30, and the spacer region 120, while also keeping costs relatively low.

[0112] Specifically, in such embodiments, the preferred ratio of the second thickness D2 to the fifth thickness D5 may be, for example, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.55, 1.6, 1.65, 1.7, 1.75, 1.8 or any value between 1.1 and 1.8.

[0113] In some embodiments, the difference between the second thickness D2 and the fifth thickness D5 can be 2nm-50nm. Thus, by rationally designing the thickness difference between the two, the passivation effect of the regions of the solar cell 100 can achieve a better matching effect, thereby improving the performance of the solar cell 100.

[0114] In such an embodiment, the difference between the second thickness D2 and the fifth thickness D5 is preferably 20nm-40nm. Through repeated research and verification, the inventors of this disclosure have discovered that setting the difference between the second thickness D2 and the fifth thickness D5 within this preferred range in a back-contact solar cell allows for optimal matching of the passivation effects of the corresponding regions of the P-type doped layer 20, the N-type doped layer 30, and the spacer region 120, thereby improving the performance of the solar cell 100 while maintaining relatively low cost.

[0115] Specifically, in such an embodiment, the difference between the second thickness D2 and the fifth thickness D5 is preferably any value between 20nm, 22nm, 24nm, 26nm, 28nm, 30nm, 32nm, 34nm, 36nm, 38nm, 40nm, or 20nm-40nm.

[0116] In some embodiments, the second thickness D2 can be 50nm-200nm, and the fifth thickness D5 can be 48nm-150nm. Thus, by setting the second thickness D2 and the fifth thickness D5 within the aforementioned ranges, the passivation film layer 40 can achieve a good passivation effect at a low cost.

[0117] In such an embodiment, the second thickness D2 can be 50nm-200nm, and the fifth thickness D5 is preferably 30nm-160nm. Specifically, through repeated research and verification, the inventors of this disclosure have found that setting the second thickness D2 and the fifth thickness D5 within this preferred range allows the passivation effect of the regions corresponding to the P-type doped layer 20, the N-type doped layer 30, and the spacer region 120 to achieve the optimal matching effect, while also keeping the cost relatively low.

[0118] In a preferred embodiment, the first thickness D1 is preferably 55nm-230nm, the second thickness D2 is preferably 50nm-200nm, and the fifth thickness D5 is preferably 30nm-160nm. The difference between the first thickness D1 and the second thickness D2 is preferably 5nm-30nm, the difference between the second thickness D2 and the fifth thickness D5 is preferably 20nm-40nm, the ratio of the first thickness D1 to the second thickness D2 is preferably 1.025-1.6, and the ratio of the second thickness D2 to the fifth thickness D5 is preferably 1.1-1.8. This allows for optimal matching of passivation effects among the P-type doped layer 20, the N-type doped layer 30, and the spacer region 120 in the intermediate region 112, improving the performance of the solar cell 100 while maintaining relatively low cost.

[0119] In some embodiments, the resistivity of silicon wafer 10 is greater than 20 ohm·cm, and the difference between the second thickness D2 and the fifth thickness D5 is 10 nm-60 nm.

[0120] Thus, when the silicon wafer 10 is a high-resistivity silicon wafer 10 with a resistance greater than 20 ohm·cm, setting the difference between the second thickness D2 and the fifth thickness D5 within this range can ensure the passivation effect of the spacer region 120 while also enabling the passivation effect of the region corresponding to the P-type doped layer 20 to reach a better state.

[0121] Referring to Figure 6, in some embodiments, the spacer region 120 is a trench 121 formed on the back surface 12 (that is, a trench 121 is formed on the back surface 12 of the silicon wafer 10, and the P-type doped layer 20 and the N-type doped layer 30 are isolated by the trench 121). The passivation film layer 40 covers the side surface 1211 and the bottom surface 1222 of the trench 121. The thickness of at least a portion of the passivation film layer 40 on the side surface 1211 of the trench 121 is greater than the thickness of the passivation film layer 40 on the bottom surface 1212 of the trench 121.

[0122] This can improve the passivation matching effect at trench 121, thereby improving the overall passivation performance and enhancing the performance of solar cell 100.

[0123] Specifically, in such an embodiment, at the doped layers located on both sides of the trench 121, the P-type doped layer 20 typically forms a P-type inner expansion layer (not shown) in the silicon wafer 10, and the N-type doped layer 30 forms an N-type inner expansion layer (not shown) in the silicon wafer 10. The P-type inner expansion layer and the N-type inner expansion layer are exposed on the side 1211 of the trench 121. Therefore, in order to improve the passivation effect at the trench 121, the thickness of the passivation film layer 40 on the P-type inner expansion layer and the N-type inner expansion layer exposed from the trench 121 can be set to be thicker, thereby improving the electrical performance of the solar cell 100.

[0124] More specifically, the thickness of the passivation film layer 40 located on the N-type inner expansion layer at the trench 121 can be basically the same as or slightly less than the first thickness D1, and the thickness of the passivation film layer 40 located on the P-type inner expansion layer is basically the same as or slightly less than the second thickness D2.

[0125] Referring to Figure 7, in some embodiments, the N-type doped layer 30 may have a first extension portion 31 extending above and suspended above the trench 121. A passivation film layer 40 is present at the end of the first extension portion 31 and on the surface 311 of the first extension portion 31 facing the trench 121. The thickness of the passivation film layer 40 on the surface 311 of the first extension portion 31 facing the trench 121 is greater than the thickness of the passivation film layer 40 on the bottom surface 1212 of the trench 121. Thus, when the N-type doped layer 30 has the first extension portion 31, the passivation effect of the N-type doped layer 30 can be further improved.

[0126] Furthermore, referring to Figure 8, in some embodiments, the P-type doped layer 20 may have a second extension portion 21 extending above and suspended above the trench 121. A passivation film layer 40 is present at the end of the second extension portion 21 and on its surface 211 facing the trench 121. The thickness of the passivation film layer 40 on the surface 211 of the second extension portion 21 facing the trench 121 is greater than the thickness of the passivation film layer 40 on the bottom surface 1212 of the trench 121. Thus, when the P-type doped layer 20 has a second extension portion 21, the passivation effect of the P-type doped layer 20 can be further improved.

[0127] Referring to Figure 9, in some embodiments, the spacer region 120 may also be a boss 122 located between adjacent P-type doped layers 20 and N-type doped layers 30. The top surface 1221 of the boss 122 is higher than the top of the P-type doped layer 20 and the N-type doped layer 30. Both the top surface 1221 and the side surface 1222 of the boss 122 have passivation film layers 40. The thickness of the passivation film layer 40 on the top surface 1221 of the boss 122 is greater than the thickness of the passivation film layer 40 on the side surface 1222 of the boss 122.

[0128] Thus, when doping occurs on the top of the boss 122, a thicker passivation film layer 40 at the top can improve the passivation effect. It can be understood that the side 1222 of the boss 122 refers to the side wall surface of the boss 122 that protrudes from the protruding portion of the P-type doped layer 20 and the N-type doped layer 30.

[0129] In the description of this specification, references to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with the described embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions 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 one or more embodiments or examples.

[0130] Furthermore, the above description is merely a preferred embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A solar cell, characterized by, Comprising: a silicon wafer having opposite first and second surfaces; a P-type doped layer and an N-type doped layer disposed on the first surface of the silicon wafer; and a passivation film layer disposed on the P-type doped layer and the N-type doped layer; wherein the passivation film layer on at least a portion of the N-type doped layer has a first thickness, and the passivation film layer on at least a portion of the P-type doped layer has a second thickness, the first thickness being greater than the second thickness. The first surface has an edge region and a middle region, the middle region being located inward of the edge region, the edge region being closer to an edge of the first surface than the middle region; 2. The solar cell according to claim 1, wherein wherein a portion of the N-type doped layer on the middle region is a first N-type doped portion, the passivation film layer on the first N-type doped portion has the first thickness, and a portion of the P-type doped layer on the middle region is a first P-type doped portion, the passivation film layer on the first P-type doped portion has the second thickness. A portion of the N-type doped layer on the edge region is a second N-type doped portion, the passivation film layer on the second N-type doped portion has a third thickness, a portion of the P-type doped layer on the edge region is a second P-type doped portion, the passivation film layer on the second P-type doped portion has a fourth thickness, the third thickness being greater than the first thickness, and the fourth thickness being greater than the second thickness.

3. The solar cell according to claim 2, wherein The third thickness is greater than the fourth thickness.

4. The solar cell of claim 3, wherein, The passivation film layer covering the middle region is a unitary continuous structure.

5. The solar cell of claim 2, wherein, The ratio of the first thickness to the second thickness is greater than 1 and less than or equal to 2.

6. The solar cell according to any one of claims 1 to 5, wherein The ratio of the first thickness to the second thickness is 1.025-1.

6.

7. The solar cell of claim 6, wherein, The difference between the first thickness and the second thickness is 2nm-50nm.

8. The solar cell according to any one of claims 1 to 5, wherein The difference between the first thickness and the second thickness is 5nm-30nm.

9. The solar cell of claim 8, wherein, The first thickness is 52nm-250nm, and the second thickness is 50nm-200nm.

10. The solar cell as claimed in any one of claims 1-5, wherein, The first thickness is 55nm-230nm, and the second thickness is 50nm-200nm.

11. The solar cell of claim 10, wherein, On the middle region, there is a spacing region between adjacent P-type doped layer and N-type doped layer, the passivation film layer also covers the spacing region, a portion of the passivation film layer on the spacing region has a fifth thickness, the second thickness being greater than the fifth thickness.

12. The solar cell of claim 2, wherein, On the middle region, the passivation film layer on the P-type doped layer, the passivation film layer on the N-type doped layer, and the passivation film layer at the spacing region are a unitary continuous structure.

13. The solar cell of claim 12, wherein, The ratio of the second thickness to the fifth thickness is greater than 1 and less than or equal to 2.

14. The solar cell of claim 12, wherein, The ratio of the second thickness to the fifth thickness is 1.1-1.

8.

15. The solar cell of claim 14, wherein, The difference between the second thickness and the fifth thickness is 2nm-50nm.

16. The solar cell of claim 12, wherein, The difference between the second thickness and the fifth thickness is 20nm-40nm.

17. The solar cell of claim 16, wherein, The second thickness is 50nm-200nm, and the fifth thickness is 48nm-150nm.

18. The solar cell of claim 12, wherein, ​ 19. The solar cell of claim 18, wherein, The second thickness is 50-200 nm, and the fifth thickness is 30-160 nm.

20. The solar cell of claim 12, wherein, The silicon wafer has a resistivity greater than 20 ohm.cm, and the difference between the second thickness and the fifth thickness is 10-60 nm.

21. The solar cell of claim 12, wherein, The interval region is a groove formed on the first surface, and the passivation film layer covers the side and bottom surfaces of the groove, and the thickness of at least a portion of the passivation film layer on the side surface of the groove is greater than the thickness of the passivation film layer on the bottom surface of the groove.

22. The solar cell of claim 21, wherein, The solar cell wafer further satisfies at least one of the following conditions: The N-type doped layer has a first extension part extending above and overhanging above the groove, and the passivation film layer is on the end of the first extension part and the surface of the first extension part facing the groove, wherein the thickness of the passivation film layer on the surface of the first extension part facing the groove is greater than the thickness of the passivation film layer on the bottom surface of the groove. The P-type doped layer has a second extension part extending above and overhanging above the groove, and the passivation film layer is on the end of the second extension part and the surface of the second extension part facing the groove, wherein the thickness of the passivation film layer on the surface of the second extension part facing the groove is greater than the thickness of the passivation film layer on the bottom surface of the groove.

23. The solar cell of claim 12, wherein, The interval region is a protrusion between the adjacent P-type doped layer and N-type doped layer, the top surface of the protrusion is higher than the top of the P-type doped layer and N-type doped layer, and the top surface and side surface of the protrusion have the passivation film layer, and the thickness of the passivation film layer on the top surface of the protrusion is greater than the thickness of the passivation film layer on the side surface of the protrusion.

24. The solar cell of claim 2, wherein, The portion of the passivation film layer on the intermediate region includes a first type passivation sub-layer and a second type passivation sub-layer arranged in layers, and the thickness of the passivation film layer on the intermediate region is the sum of the thicknesses of the first type passivation sub-layer and the second type passivation sub-layer. The thickness of the portion of the first type passivation sub-layer on the N-type doped layer is greater than the thickness of the portion of the first type passivation sub-layer on the P-type doped layer.

25. The solar cell of claim 24, wherein, The thickness of the portion of the second type passivation sub-layer on the N-type doped layer is equal to the thickness of the portion of the second type passivation sub-layer on the P-type doped layer.

26. The solar cell of claim 25, wherein, The first type passivation sub-layer is prepared by a PECVD process or a thermal growth process, and the second type passivation sub-layer is prepared by an atomic deposition process.

27. The solar cell as claimed in any one of claims 24-26, wherein, The first type passivation sub-layer includes at least one of a silicon oxide film layer, a silicon nitride film layer, and a silicon oxynitride film layer, and the second type passivation sub-layer includes an aluminum oxide film layer.

28. The solar cell of claim 27, wherein, The silicon oxide film layer is a plurality of layers of silicon oxide arranged in layers, the silicon nitride film layer is a plurality of layers of silicon nitride arranged in layers, and the silicon oxynitride film layer is a plurality of layers of silicon oxynitride arranged in layers.

29. A battery assembly comprising: The solar cell wafer of any one of claims 1-28.

30. A photovoltaic system characterized by, The battery assembly of claim 29.

Images