Solar cells, battery modules, and photovoltaic power generation systems

Abstract

This disclosure applies to the field of solar cells and provides solar cells, battery modules, and photovoltaic power generation systems. [Solution] In a solar cell, a P-type doped layer and an N-type doped layer are provided on the first surface of a silicon wafer, and the thickness of the passivation film layer on at least a portion of the N-type doped layer is greater than the thickness of the passivation film layer on at least a portion of the P-type doped layer. This allows for an optimized design of different thickness combinations for the passivation film layers on at least a portion of the N-type doped layer and at least a portion of the P-type doped layer, and by increasing the thickness of the passivation film layer on at least a portion of the N-type doped layer, the passivation effect in different doped regions of the solar cell can be matched to an excellent effect, improving the performance of the solar cell, saving on material usage, and reducing costs.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present disclosure claims priority to a Chinese patent application filed with the National Intellectual Property Administration of China on July 24, 2024, with application number 202411000080.2 and titled "Solar Cell, Battery Module and Photovoltaic Power Generation System", the entire content of which is incorporated into the present disclosure by reference. Technical Field

[0002] The present disclosure relates to the technical field of solar cells, and in particular, to a solar cell, a battery module and a photovoltaic power generation system. Background Art

[0003] Solar cell power generation is a sustainable clean energy source, which can convert sunlight into electrical energy by utilizing the photovoltaic effect of the p-n junction of semiconductors. 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 doped layer to passivate the cell.

[0004] In existing solar cells, sufficient consideration has not been given to the optimization of the mutual combination between the passivation film layers of the P-type doped layer and the N-type doped layer, and the passivation effect has not been improved, so the performance of existing solar cells is not sufficient. Summary of the Invention

[0005] The present disclosure provides a solar cell, a battery module and a photovoltaic power generation system.

[0006] The present disclosure is implemented as follows. The solar cell according to an embodiment of the present disclosure includes: a silicon wafer having opposing first and second surfaces; a P-type doped layer and an N-type doped layer provided on the first surface of the silicon wafer; a passivation film layer respectively provided 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, wherein the first thickness is greater than the second thickness.

[0007] In some embodiments, the first surface has an edge region and an intermediate region, the intermediate region is located inside the edge region, and the edge region is closer to the edge of the first surface than the intermediate region. The portion of the N-type doped layer located in the intermediate region is a first N-type doped portion, and the passivation film layer located on the first N-type doped portion has the first thickness; the portion of the P-type doped layer located in the intermediate region is a first P-type doped portion, and the passivation film layer located on the first P-type doped portion has the second thickness.

[0008] In some embodiments, the portion of the N-type doped layer located in the edge region is a second N-type doped portion, the passivation film layer located on the second N-type doped portion has a third thickness, the portion of the P-type doped layer located in the edge region is a second P-type doped portion, the passivation film layer located on the second P-type doped portion has a fourth thickness, the third thickness is greater than the first thickness, and the fourth thickness is greater than the second thickness.

[0009] In some embodiments, the third thickness is greater than the fourth thickness.

[0010] In some embodiments, the passivation film layer covering the intermediate region has an integral, continuous structure.

[0011] In some embodiments, the ratio of the first thickness to the second thickness is greater than 1 and less than or equal to 2.

[0012] In some embodiments, the ratio of the first thickness to the second thickness is between 1.025 and 1.6.

[0013] In some embodiments, the difference between the first thickness and the second thickness is 2 nm to 50 nm.

[0014] In some embodiments, the difference between the first thickness and the second thickness is 5 nm to 30 nm.

[0015] In some embodiments, the first thickness is 52 nm to 250 nm, and the second thickness is 50 nm to 200 nm.

[0016] In some embodiments, the first thickness is 55 nm to 230 nm, and the second thickness is 50 nm to 200 nm.

[0017] In some embodiments, in the intermediate region, there is a gap between adjacent P-type doped layers and N-type doped layers, the passivation film layer also covers the gap, the portion of the passivation film layer located in the gap has a fifth thickness, and the second thickness is greater than the fifth thickness.

[0018] In some embodiments, in the intermediate region, the passivation film layer on the P-type dope layer, the passivation film layer on the N-type dope layer, and the passivation film layer in the intervening region form an integrated continuous structure.

[0019] In some embodiments, the second thickness and the 5 The ratio of the thickness is greater than 1 and less than or equal to 2.

[0020] In some embodiments, the second thickness and the 5 The ratio of thickness is 1.1 to 1.8.

[0021] In some embodiments, the second thickness and the 5 The difference in thickness is between 2nm and 50nm.

[0022] In some embodiments, the second thickness and said 5 thickness is 20 nm to 40 nm.

[0023] In some embodiments, the second thickness is 50 nm to 200 nm, and said 5 thickness is 48 nm to 150 nm.

[0024] In some embodiments, the second thickness is 50 nm to 200 nm, and said 5 thickness is 30 nm to 160 nm.

[0025] In some embodiments, the resistivity of the silicon wafer is greater than 20 Ωcm, and the difference between the second thickness and said 5 thickness is 10 nm to 60 nm.

[0026] In some embodiments, the spacing region is a trench formed in the first surface, the passivation film layer covers the side surface and the bottom surface of the trench, and the thickness of at least a partial region of the passivation film layer located on the side surface of the trench is greater than the thickness of the passivation film layer located on the bottom surface of the trench.

[0027] In some embodiments, the solar cell further comprises: the N-type doped layer has a first extension portion extending above the trench and suspended above the trench, the passivation film layer is provided on both the end of the first extension portion and the surface of the first extension portion facing the trench, and the thickness of the passivation film layer located on the surface of the first extension portion facing the trench is greater than the thickness of the passivation film layer located on the bottom surface of the trench, The P-type doped layer has a second extending portion that extends above the groove and is suspended above the groove, and the passivation film layer is located at either the end of the second extending portion or on the surface of the second extending portion facing the groove, and the thickness of the passivation film layer located on the surface of the second extending portion facing the groove is greater than the thickness of the passivation film layer located on the bottom surface of the groove. It satisfies at least one of our criteria.

[0028] In some embodiments, the spacing region is a convex base located between adjacent P-type doped layers and N-type doped layers, the top surface of the convex base is higher than the tops of the P-type doped layer and the N-type doped layer, the passivation film layer is located on either the top surface or the side surface of the convex base, and the thickness of the passivation film layer located on the top surface of the convex base is greater than the thickness of the passivation film layer located on the side surface of the convex base.

[0029] In some embodiments, the portion of the passivation film layer located in the intermediate region includes a first type of passivation sublayer and a second type of passivation sublayer that are laminated together, and the thickness of the passivation film layer located in the intermediate region is the sum of the thicknesses of the first type of passivation sublayer and the second type of passivation sublayer. The thickness of the portion of the first type of passivation sublayer located on the N-type doped layer is greater than the thickness of the portion of the first type of passivation sublayer located on the P-type doped layer.

[0030] In some embodiments, the thickness of the portion of the second type of passivation sublayer located on the N-type doped layer is equal to the thickness of the portion of the second type of passivation sublayer located on the P-type doped layer.

[0031] In some embodiments, the first type of passivation sublayer is manufactured by a PECVD process or a thermal growth process, and the second type of passivation sublayer is manufactured by an atomic deposition process.

[0032] In some embodiments, the first type of passivation sublayer comprises at least one of a silicon oxide film layer, a silicon nitride film layer, and a silicon oxynitride film layer, and the second type of passivation sublayer comprises an aluminum oxide film layer.

[0033] In some embodiments, the silicon oxide film layer is a sequentially stacked multilayer silicon oxide, the silicon nitride film layer is a sequentially stacked multilayer silicon nitride, and the silicon oxynitride film layer is a sequentially stacked multilayer silicon oxynitride.

[0034] This disclosure further provides a battery module comprising several of the solar cells described in any one of the above paragraphs.

[0035] This disclosure further provides a photovoltaic power generation system including the battery module described above. [Effects of the Invention]

[0036] In the solar cell, battery module, and photovoltaic power generation system of the embodiments of this disclosure, a P-type doped layer and an N-type doped layer are provided on the first surface of a silicon wafer, and the thickness of the passivation film layer in at least a portion of the N-type doped layer is greater than the thickness of the passivation film layer in at least a portion of the P-type doped layer. This allows for an optimized design of different thickness combinations for the passivation film layers on at least a portion of the N-type doped layer and at least a portion of the P-type doped layer, and by increasing the thickness of the passivation film layer on at least a portion of the N-type doped layer, it is possible to achieve a superior matched effect in the passivation effect in different doped regions of the solar cell, improve the performance of the solar cell, save on material usage, and reduce costs.

[0037] Additional aspects and benefits of this disclosure are partially shown in the following description, partially become apparent from the following description, or will be understood through the practice of this disclosure. [Brief explanation of the drawing]

[0038] [Figure 1] This is a schematic diagram of a module for a photovoltaic power generation system according to an embodiment of the present disclosure. [Figure 2] This is a schematic diagram of the cross-sectional structure of a solar cell according to an embodiment of the present disclosure. [Figure 3] This is a schematic plan view of a partial structure of a solar cell according to an embodiment of the present disclosure. [Figure 4] This is a schematic diagram of the cross-sectional structure in the intermediate region of a solar cell according to an embodiment of the present disclosure. [Figure 5] This is a schematic diagram of the structure of the passivation film layer according to an embodiment of the present disclosure. [Figure 6] This is a schematic diagram of another cross-sectional structure in the intermediate region of a solar cell according to an embodiment of the present disclosure. [Figure 7] This is a schematic diagram of yet another cross-sectional structure in the intermediate region of a solar cell according to an embodiment of the present disclosure. [Figure 8] This is a schematic diagram of yet another cross-sectional structure in the intermediate region of a solar cell according to an embodiment of the present disclosure. [Figure 9] This is a schematic diagram of yet another cross-sectional structure in the intermediate region of a solar cell according to an embodiment of the present disclosure. [Modes for carrying out the invention]

[0039] To further clarify the purpose, technical proposal, and advantages of this disclosure, the disclosure will be described in more detail below with reference to the drawings and examples. Examples of the above examples are shown in the drawings, and the same or similar reference numerals indicate the same or similar elements or elements having the same or similar function. The examples described below with reference to the drawings are illustrative and for illustrative purposes only, and should not be construed as limiting the disclosure. Furthermore, it should be understood that the specific examples described herein are for illustrative purposes only, and not limiting the disclosure.

[0040] In the description of this disclosure, the orientations or positional relationships indicated by terms such as “top,” “bottom,” “left,” “right,” “top,” “bottom,” and “side” are based on the orientations or positional relationships shown in the drawings and are intended to facilitate and simplify the description of this disclosure, and do not indicate or imply that the device or element has a specific orientation, or that it must be configured and operated in a specific orientation. Therefore, they should not be understood as limitations on this disclosure.

[0041] Furthermore, terms such as “first,” “second,” etc., are used solely for descriptive purposes and should not be understood as indicating or implying relative importance or the quantity of the indicated technical feature. Accordingly, features limited to “first,” “second,” etc., may explicitly or implicitly include one or more such features. In the description of this disclosure, “several” means two or more unless otherwise clearly and specifically limited.

[0042] In this disclosure, unless otherwise expressly defined and limited, "above" or "below" the first feature of the second feature includes cases where the first and second features are in direct contact, and cases where they are in contact but not in direct contact, via other features interposed between them. Furthermore, "above," "above," or "on the top surface" of the second feature includes cases where the first feature is directly above or obliquely above the second feature, or simply indicates that the horizontal height of the first feature is higher than that of the second feature. "Below," "below," or "on the bottom surface" of the second feature includes cases where the first feature is directly below or obliquely below the second feature, or simply indicates that the horizontal height of the first feature is lower than that of the second feature.

[0043] The following disclosure provides numerous different embodiments or examples for realizing the different structures of this disclosure. To simplify the scope of this disclosure, the following describes the components and installations of specific examples. Of course, these are merely illustrative and not intended to limit this disclosure. Also, while this disclosure may use reference numbers and / or reference letters repeatedly in different examples, such repetition is for simplification and clarity and does not in itself indicate a relationship between each embodiment and / or installation discussed. Also, while this disclosure provides examples of various specific processes and materials, those skilled in the art may conceive of applications of other processes and / or use of other materials.

[0044] Referring to Figure 1, the photovoltaic power generation system 1000 in the embodiments of the present disclosure may include a battery module 200 in the embodiments of the present disclosure, and the battery module 200 in the embodiments of the present disclosure may include several solar cells 100 in the embodiments of the present disclosure. Several solar cells 100 may be connected via welding ribbons to form several battery strings, and each battery string may form a battery module 200 in series, parallel, or series-parallel connection manner.

[0045] Referring to Figure 2, the solar cell 100 in the embodiment of this disclosure may include a silicon wafer 10, a P-type doped layer 20, an N-type doped layer 30, and a passivation film layer 40. The silicon wafer 10 has opposing first surface 11 and second surface 12, and both the P-type doping layer 20 and the N-type doping layer 30 are provided on the first surface 11 of the silicon wafer 10. The passivation film layer 40 covers the first surface 11, and both the P-type doping layer 20 and the N-type doping layer 30 are covered with the passivation film layer 40. As shown in Figure 2, the passivation film layer 40 in at least a portion of the N-type doped layer 30 has a first thickness D1, and the passivation film layer 40 in at least a portion of the P-type doped layer 20 has a second thickness D2, with the first thickness D1 being greater than the second thickness D2.

[0046] In the solar cell 100, battery module 200, and photovoltaic power generation system 1000 in the embodiments of this disclosure, a P-type doped layer 20 and an N-type doped layer 30 are provided on the first surface 11 of the silicon wafer 10, and the thickness of the passivation film layer 40 on at least a portion of the N-type doped layer 30 is greater than the thickness of the passivation film layer 40 on at least a portion of the P-type doped layer 20, i.e., the first thickness D1 is greater than the second thickness D2. By optimizing the combination of different thicknesses for the passivation film layer 40 on at least a portion of the N-type doped layer 30 and at least a portion of the P-type doped layer 20 in this way, and by increasing the thickness of the passivation film layer 40 on at least a portion of the N-type doped layer 30, the passivation effect in different doped regions of the solar cell 100 can be made to a superior matched effect, thereby improving the performance of the solar cell 100, saving on material use, and reducing costs.

[0047] Specifically, in the embodiments of this disclosure, the first surface 11 is the back surface of the silicon wafer 10, and the second surface 12 is the front surface of the silicon wafer 10. The solar cell 100 is preferably a back-contact type solar cell. Of course, in some embodiments, the solar cell 100 may be other types of battery cells having both a P-type doped layer 20 and an N-type doped layer 30 on the same surface, and is not specifically limited herein. The silicon wafer 10 may be a P-type silicon wafer or an N-type silicon wafer, and is not specifically limited here. The P-type doped layer 20 may be of the type of P-type doped polycrystalline silicon layer, P-type doped microcrystalline silicon layer, etc., and the N-type doped layer 30 may be of the type of N-type doped polycrystalline silicon layer, N-type doped microcrystalline silicon layer, etc. The P-type doped layer 20 and the N-type doped layer 30 can be manufactured by methods such as diffusion and deposition, and are not specifically limited here.

[0048] In this disclosure, the thickness of the passivation film layer 40 on the N-type doped layer 30 means the thickness of the passivation film layer 40 on all surfaces covered by the passivation film layer 40 of the N-type doped layer 30. Similarly, the thickness of the passivation film layer 40 on the P-type doped layer 20 means the thickness of the passivation film layer 40 on all surfaces covered by the passivation film layer 40 of the P-type doped layer 20. Furthermore, in this specification, "covering" a particular surface or film layer means that the film layer may be directly laminated on the surface or the particular film layer, or another film layer may be provided between the film layer and the surface or film layer. The expression "covering" merely limits the specific installation area of ​​the film layer.

[0049] In a back-contact solar cell, it can be understood that the first surface 11 has several P-type doped layers 20 and several N-type doped layers 30, and that the P-type doped layers 20 and several N-type doped layers 30 are arranged in sequentially alternating rows. Furthermore, it is easily understood that in a back-contact solar cell, a tunnel layer (not shown) can usually be further provided between the P-type doped layers 20 and N-type doped layers 30 and the silicon wafer 10.

[0050] Referring to Figures 2 and 4, in some embodiments, the first surface 11 has an edge region 111 and an intermediate region 112, and the intermediate region 112 This is the marginal region. 111 Located on the inside, the edge region 111 is closer to the edge of the first surface 11 compared to the intermediate region 112. Here, the passivation film layer 40 located on the intermediate region 112 of the N-type doped layer 30 has a first thickness D1, and the passivation film layer 40 located on the intermediate region 112 of the P-type doped layer 20 has a second thickness D2. This allows for an excellent passivation effect in the regions corresponding to the N-type doped layer 30 and the P-type doped layer 20 at the intermediate region 112, thereby improving the performance of the solar cell 100.

[0051] Specifically, as shown in Figure 2, in such an embodiment, the silicon wafer 10 further includes several side surfaces 13 connecting the first surface 11 and the second surface 12, the edge region 111 is located at the boundary edge position between the first surface 11 and the side surface 13, the intermediate region 112 is located at an intermediate position on the first surface 11, and the edge region 111 is located between the intermediate region 112 and the side surface 13. As shown in Figure 2, the "edge region 111" refers to the region located near the edge of the boundary between the first surface 11 and the side surface 13, and the "intermediate region 112" refers to the region of the first surface 11 excluding the edge region 111.

[0052] As shown in Figure 3 (the passivation film layer 40 is not shown in Figure 3), in some embodiments, the specific installation method of the intermediate region 112 and the edge region 111 can be configured as shown in Figure 3. In such embodiments, the edge region 111 is provided so as to surround the intermediate region, that is, the edge region 111 is provided at the boundary between the edge of the first surface 11 and all the side surfaces 13, while the intermediate region 112 is located within the edge region 110, that is, the edge region 11 is a region located at each edge position of the first surface 11. Of course, in some embodiments, there may be no edge region at the boundary between a part of the first surface 11 and the side surface 13. For example, in one possible embodiment, in a half cell, after cutting is complete, a cut surface is formed on the half cell, and the cut surface also becomes the side surface 13. In such a case, there is no edge region 110 at the boundary edge between the first surface 11 and the cut surface, but there is an edge region 110 near other boundary edges.

[0053] Referring to Figure 2, in some embodiments, the passivation film layer 40 in the portion of the N-type doped layer 30 located on the edge region 111 has a third thickness D3, and the passivation film layer 40 in the portion of the P-type doped layer 20 located on the edge region 111 has a fourth thickness D4, where the third thickness D3 is greater than the first thickness D1, and the fourth thickness D4 is greater than the second thickness D2. This allows for a thicker passivation film layer in the doped layer on the edge region 111, thereby enhancing the passivation effect of the edge region 111, reducing edge recombination, and further improving the efficiency of the solar cell 100.

[0054] Furthermore, in such embodiments, the third thickness D3 can be made larger than the fourth thickness D4. This allows for the optimization of different thickness combinations for the passivation film layer 40 on the N-type doped layer 30 and the P-type doped layer 20 in the edge region 111, and by increasing the thickness of the passivation film layer 40 on the N-type doped layer 30, the passivation effect in the edge region 11 can be made to an optimally matched effect.

[0055] In some embodiments, the passivation film layer 40 covering the intermediate region 112 has an integral, continuous structure. In this way, the passivation film layer 40 in that portion can be manufactured in one go via the PECVD process, and different thicknesses can be achieved in different regions by controlling the conductivity of different regions during the manufacturing process. Specifically, in this specification, "integrated continuous structure" means that the material and structure of the passivation film layer 40 in each part are identical, and that the passivation film layer 40 in each part is a single continuous film layer manufactured in a single process, with only the thickness differing in different regions. When similar descriptions appear in the following explanation, please refer to this interpretation for understanding.

[0056] In the solar cell 100, a metal electrode is further provided, and the metal electrode penetrates the passivation film layer 40 and contacts the doping layer, that is, in a subsequent manufacturing process, when the metal electrode is manufactured, the passivation film layer 40 at the position corresponding to the metal electrode is removed or ablated. Specifically, in a back-contact type solar cell, there is a P-type electrode and an N-type electrode (not shown), the P-type electrode penetrates the passivation film layer 40 and contacts the P-type doping layer 20, and the N-type electrode penetrates the passivation layer40 Penetrating through the N-type doped layer 30 Make contact with them.

[0057] Referring to Figure 5, in some embodiments, the portion of the passivation film layer 40 located in the intermediate region 112 may include a first type of passivation sublayer 41 and a second type of passivation sublayer 42 that are laminated together, and the thickness of the passivation film layer 40 located in the intermediate region 112 is the sum of the thicknesses of the first type of passivation sublayer 41 and the second type of passivation sublayer 42. Here, the thickness of the portion where the first type of passivation sublayer 41 is located on the N-type doped layer 30 is greater than the thickness of the portion where the first type of passivation sublayer 41 is located on the P-type doped layer 20. As a result, on the one hand, the passivation effect can be improved by employing different types of passivation sublayer structures in the intermediate region 112, and on the other hand, by setting the thickness of the first type of passivation sublayer 41 located on the N-type doped layer 30 to be greater than the thickness located on the P-type doped layer 20, the thickness of the passivation layer 40 on the intermediate region 112 located on the N-type doped layer 30 can be made greater than the thickness on the P-type doped layer 20.

[0058] Furthermore, in such embodiments, the thickness of the portion of the second type of passivation sublayer 42 located on the N-type doped layer 30 can be equal to the thickness of the portion of the second type of passivation sublayer 42 located on the P-type doped layer 20.

[0059] In some embodiments, the first type of passivation sublayer 41 is manufactured by a PECVD process or a thermal growth process, and the second type of passivation sublayer 42 is manufactured by an atomic deposition process. Specifically, in the embodiments of this disclosure, the first type of passivation sublayer 41 may 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 of passivation sublayer 42 may include an aluminum oxide film layer.

[0060] As shown in Figure 5, in some embodiments, the passivation film layer 40 in the intermediate region 112 can employ a three-layer laminated structure consisting of a silicon oxide film layer 401, an aluminum oxide film layer 402, and a silicon nitride film layer 403. 402 The thickness of the P-type doped layer 20 and the N-type doped layer 30 are basically the same, the thickness of the N-type doped layer 30 of the silicon oxide film layer 401 is greater than the thickness of the P-type doped layer 20 of the silicon oxide film layer 401, and the thickness of the N-type doped layer 30 of the silicon nitride film layer 403 can be greater than the thickness of the P-type doped layer 20 of the silicon nitride film layer 403. Of course, in some embodiments, the passivation film layer 40 on the intermediate region 112 can also employ only a two-layer stacked structure of an aluminum oxide film layer 402 and a silicon nitride film layer 403, and the aluminum oxide film layer 402 The thicknesses of the P-type doped layer 20 and the N-type doped layer 30 are basically the same, and the thickness of the N-type doped layer 30 of the silicon nitride film layer 403 can be greater than the thickness of the P-type doped layer 20 of the silicon nitride film layer 403.

[0061] In some embodiments, the silicon nitride film layer 403 may be a single-layer structure or a multilayer structure consisting of multiple silicon nitride layers with different refractive indices, but is not specifically limited here.

[0062] Furthermore, in some embodiments, in the solar cell 100, the silicon oxide film layer may be a sequentially stacked multilayer silicon oxide, the silicon nitride film layer may be a sequentially stacked multilayer silicon nitride, and the silicon oxynitride film layer may be a sequentially stacked multilayer silicon oxynitride. 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 multilayer structures.

[0063] 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である。 Thus, because the passivation film layer 40 on the N-type doped layer 30 in the intermediate region 112 is thick, the passivation effect in the region corresponding to the N-type doped layer 30 is improved, thereby achieving an optimal matching effect between the passivation effect in the regions corresponding to the P-type doped layer 20 and the N-type doped layer 30, and improving the performance of the solar cell 100. 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, and is not specifically limited herein.

[0064] In some embodiments, the ratio of the first thickness D1 to the second thickness D2 is preferably 1.025 to 1.6. As a result of diligent research and verification by the inventors of this disclosure, it has been found that setting the ratio of the first thickness D1 to the second thickness D2 within this preferred range allows for optimal matching of the passivation effect in the regions corresponding to the P-type doped layer 20 and the N-type doped layer 30, while keeping costs relatively low. 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 between 1.025 and 1.6.

[0065] In some embodiments, the difference between the first thickness D1 and the second thickness D2 can be 2 nm to 50 nm. By rationally designing the difference in thickness between the two, the passivation effect in the regions corresponding to the P-type doped layer 20 and the N-type doped layer 30 can be optimized, thereby improving the performance of the solar cell 100. In such embodiments, the difference between the first thickness D1 and the second thickness D2 is preferably 5 nm to 30 nm. As a result of diligent research and verification by the inventors of this disclosure, it has been found that setting the difference between the first thickness D1 and the second thickness D2 within this preferred range allows for optimal matching of the passivation effect in the regions corresponding to the P-type doped layer 20 and the N-type doped layer 30, while keeping costs relatively low. Specifically, in such embodiments, the difference between the first thickness D1 and the second thickness D2 is preferably 5nm, 7nm, 9nm, 10nm, 12nm, 14nm, 16nm, 18nm, 20nm, 22nm, 24nm, 26nm, 28nm, 30nm, or any value between 5nm and 30nm.

[0066] In some embodiments, the first thickness D1 may be 52 nm to 250 nm, and the second thickness D2 may be 50 nm to 200 nm. By setting the first thickness D1 and the second thickness D2 within the above ranges, the passivation film layer 40 can achieve a good passivation effect and keep costs low. In such embodiments, the first thickness D1 is preferably 55 nm to 230 nm, and the second thickness D2 is preferably 50 nm to 200 nm. As a result of diligent research and verification by the inventors of this disclosure, it has been found that by setting the sizes of the first thickness D1 and the second thickness D2 within this preferred range, the passivation effect in the regions corresponding to the P-type doped layer 20 and the N-type doped layer 30 can be achieved to an optimal matching effect while keeping costs relatively low. In one preferred embodiment, the first thickness D1 is preferably 55 nm to 230 nm, the second thickness D2 is preferably 50 nm to 200 nm, the difference between the first thickness D1 and the second thickness D2 is preferably 5 nm to 30 nm, and the ratio of the first thickness D1 to the second thickness D2 is preferably 1.025 to 1.6. This allows for optimal matching of the passivation effect in the regions corresponding to the P-type doped layer 20 and the N-type doped layer 30, while keeping costs relatively low.

[0067] Referring to Figure 4, in some embodiments, the solar cell 100 is a back-contact type solar cell, in which case, in the intermediate region 112, a gap region 120 is provided between adjacent P-type doped layers 20 and N-type doped layers 30, the passivation film layer 40 also covers the gap region 120, and the portion of the passivation film layer 40 located in the gap region 120 has a fifth thickness D5, where the first thickness D1 is greater than the second thickness D2, and the second thickness D2 is greater than the fifth thickness D5. In this way, by rationally optimizing the thickness of the N-type doped layer 30, the P-type doped layer 20 in the intermediate region 112, and the passivation film layer 40 on the gap region 120 between them, the passivation effect in the regions corresponding to the three can be made to a good matching effect, and the electrical performance of the solar cell 100 can be improved at a relatively low cost. In this embodiment, in the intermediate 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 in the spacing region 120 form an integrated continuous structure. This allows for direct, one-time manufacturing by the PECVD process, and enables the realization of different thicknesses in different regions by controlling the conductivity of different regions during the manufacturing process.

[0068] Furthermore, in some embodiments, the ratio of the second thickness D2 to the fifth thickness D5 may be greater than 1 and less than or equal to 2, that is, 1 <D2 / D5≤2である。 In this way, by gradually increasing the thickness of the fifth thickness D5, the second thickness D2, and the first thickness D1, and designing them according to the above ratio, the passivation effect of the entire solar cell 100 can be made to an excellent matching effect, improving the performance of the solar cell 100 while keeping costs relatively low. 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, and is not specifically limited herein.

[0069] In some embodiments, the ratio of the second thickness D2 to the fifth thickness D5 in a back-contact type solar cell is preferably 1.1 to 1.8. As a result of diligent research and verification by the inventors of this disclosure, it has been found that by setting the ratio of the second thickness D2 to the fifth thickness D5 within this preferred range, the passivation effect in the regions corresponding to the P-type doped layer 20, the N-type doped layer 30, and the spacing region 120 can be optimized for optimal matching while keeping costs relatively low. Specifically, in such embodiments, the preferred ratio of the second thickness D2 to the fifth thickness D5 can 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.

[0070] In some embodiments, the difference between the second thickness D2 and the fifth thickness D5 can be 2 nm to 50 nm. By rationally designing the difference between the two thicknesses, the passivation effect in the region of the solar cell 100 can be made to a superior matching effect, thereby improving the performance of the solar cell 100. In such embodiments, the difference between the second thickness D2 and the fifth thickness D5 is preferably 20 nm to 40 nm. As a result of diligent research and verification by the inventors of this disclosure, it has been found that by setting the difference between the second thickness D2 and the fifth thickness D5 within this preferred range in a back-contact type solar cell, the passivation effect in the regions corresponding to the P-type doped layer 20, the N-type doped layer 30, and the spacing region 120 can be optimized for matching, thereby improving the performance of the solar cell 100 while keeping costs relatively low. Specifically, in such embodiments, the difference between the second thickness D2 and the fifth thickness D5 is preferably 20 nm, 22 nm, 24 nm, 26 nm, 28 nm, 30 nm, 32 nm, 34 nm, 36 nm, 38 nm, 40 nm, or any value between 20 nm and 40 nm.

[0071] In some embodiments, the second thickness D2 may be 50 nm to 200 nm, and the fifth thickness D5 may be 48 nm to 150 nm. By setting the second thickness D2 and the fifth thickness D5 within the above ranges, the passivation film layer 40 can achieve a good passivation effect while keeping costs low. In such embodiments, the second thickness D2 may be 50 nm to 200 nm, and the fifth thickness D5 is preferably 30 nm to 160 nm. Specifically, as a result of diligent research and verification by the inventors of this disclosure, it has been found that by setting the sizes of the second thickness D2 and the fifth thickness D5 within this preferred range, the passivation effect in the regions corresponding to the P-type doped layer 20, the N-type doped layer 30, and the spacing region 120 can be made to an optimal matching effect, while also keeping costs relatively low. In one preferred embodiment, the first thickness D1 is preferably 55 nm to 230 nm, the second thickness D2 is preferably 50 nm to 200 nm, the fifth thickness D5 is preferably 30 nm to 160 nm, the difference between the first thickness D1 and the second thickness D2 is preferably 5 nm to 30 nm, the difference between the second thickness D2 and the fifth thickness D5 is preferably 20 nm to 40 nm, the ratio of the first thickness D1 to the second thickness D2 is preferably 1.025 to 1.6, and the ratio of the second thickness D2 to the fifth thickness D5 is preferably 1.1 to 1.8. This allows the passivation effect in the regions corresponding to the P-type doped layer 20, the N-type doped layer 30, and the spacing region 120 in the intermediate region 112 to be optimized, improving the performance of the solar cell 100 while keeping costs relatively low.

[0072] In some embodiments, the resistivity of the silicon wafer 10 is greater than 20 Ωcm, and the difference between the second thickness D2 and the fifth thickness D5 is 10 nm to 60 nm. As a result, when the silicon wafer 10 is a high-resistance silicon wafer 10 with a resistance greater than 20 Ωcm, setting the difference between the second thickness D2 and the fifth thickness D5 within this range ensures the passivation effect of the spacing region 120 and also enables achieving a good passivation effect in the region corresponding to the P-type doped layer 20.

[0073] Referring to Figure 6, in some embodiments, the spacing region 120 is a groove 121 formed on the back surface 12 (i.e., a groove 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 groove 121), the passivation film layer 40 covers the side surface 1211 and bottom surface 1222 of the groove 121, and the thickness of at least a portion of the passivation film layer 40 located on the side surface 1211 of the groove 121 is greater than the thickness of the passivation film layer 40 located on the bottom surface 1212 of the groove 121. This improves the passivation matching effect in the groove 121, enhances the overall passivation performance, and improves the performance of the solar cell 100. Specifically, in this embodiment, in the doping layers located on both sides of the groove 121, the P-type doping layer 20 normally forms a P-type internal diffusion layer (not shown) on the silicon wafer 10, and the N-type doping layer 30 forms an N-type internal diffusion layer (not shown) on the silicon wafer 10. The P-type internal diffusion layer and the N-type internal diffusion layer are exposed on the side surface 1211 of the groove 121. Therefore, in order to improve the passivation effect in the groove 121, the electrical performance of the solar cell 100 can be improved by setting a thicker passivation film layer 40 on the P-type internal diffusion layer and the N-type internal diffusion layer exposed from the groove 121. More specifically, the thickness of the passivation film layer 40 located in the N-type internal diffusion layer in the groove 121 may be basically the same as the first thickness D1 or slightly smaller than the first thickness D1, and the thickness of the passivation film layer 40 located in the P-type internal diffusion layer may be basically the same as the second thickness D2 or slightly smaller than the second thickness D2.

[0074] Referring to Figure 7, in some embodiments, the N-type doped layer 30 has a first extended portion 31 that extends above and suspends above the groove 121, and a passivation film layer 40 is present at either the end of the first extended portion 31 or the surface 311 of the first extended portion 31 facing the groove 121, where the thickness of the passivation film layer 40 located on the surface 311 of the first extended portion 31 facing the groove 121 is greater than the thickness of the passivation film layer 40 located on the bottom surface 1212 of the groove 121. This makes it possible to further improve the passivation effect of the N-type doped layer 30 when the N-type doped layer 30 has the first extended portion 31.

[0075] Referring to Figure 8, in some embodiments, the P-type doped layer 20 may have a second extended portion 21 that extends above and suspends above the groove 121, and a passivation film layer 40 is provided at either the end of the second extended portion 21 or on the surface 211 of the second extended portion 21 facing the groove 121, where the thickness of the passivation film layer 40 located on the surface 211 of the second extended portion 21 facing the groove 121 is greater than the thickness of the passivation film layer 40 located on the bottom surface 1212 of the groove 121. This further improves the passivation effect of the P-type doped layer 20 when the P-type doped layer 20 has a second extended portion 21.

[0076] Referring to Figure 9, in some embodiments, the spacing region 120 may be a convex base 122 located between adjacent P-type doped layers 20 and N-type doped layers 30, the top surface 1221 of the convex base 122 is higher than the tops of the P-type doped layers 20 and N-type doped layers 30, and either the top surface 1221 or the side surface 1222 of the convex base 122 has a passivation film layer 40, the thickness of the passivation film layer 40 located on the top surface 1221 of the convex base 122 is greater than the thickness of the passivation film layer 40 located on the side surface 1222 of the convex base 122. Thus, when doping is performed at the top of the convex base 122, the passivation effect can be improved by setting the passivation film layer 40 at the top to be thicker. It can be understood that the side surface 1222 of the convex base 122 refers to the side wall surface of the protruding portion of the convex base 122 that protrudes from the P-type doping layer 20 and the N-type doping layer 30.

[0077] In this specification, reference terms such as “several examples,” “exemplary examples,” “examples,” “specific examples,” or “several examples” mean that the specific features, structures, materials, or properties described in relation to such examples are included in at least one example of this disclosure. In this specification, exemplary expressions for the above terms do not necessarily refer to the same example. Furthermore, the specific features, structures, materials, or properties described may be combined in an appropriate manner in any one or more examples.

[0078] Furthermore, the foregoing is merely a preferred embodiment of the Disclosure and does not limit the Disclosure. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the Disclosure shall all be within the scope of the Disclosure.

Claims

1. A silicon wafer having a first surface and a second surface facing each other, A P-type doped layer and an N-type doped layer are provided on the first surface of the silicon wafer, A passivation film layer is provided on each of the P-type doped layer and the N-type doped layer, Includes, A solar cell characterized in that 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, wherein the first thickness is greater than the second thickness.

2. The first surface has an edge region and an intermediate region, the intermediate region is located inside the edge region, and the edge region is closer to the edge of the first surface than the intermediate region. The solar cell according to claim 1, wherein the portion of the N-type doped layer located in the intermediate region is a first N-type doped portion, the passivation film layer located on the first N-type doped portion has a first thickness, the portion of the P-type doped layer located in the intermediate region is a first P-type doped portion, and the passivation film layer located on the first P-type doped portion has a second thickness.

3. The portion of the N-type doped layer located in the edge region is a second N-type doped portion, the passivation film layer located on the second N-type doped portion has a third thickness, the portion of the P-type doped layer located in the edge region is a second P-type doped portion, the passivation film layer located above the second P-type doped portion has a fourth thickness, the third thickness is greater than the first thickness, and the fourth thickness is greater than the second thickness, according to claim 2.

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

5. The solar cell according to claim 2, wherein the passivation film layer covering the intermediate region has an integral continuous structure.

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 greater than 1 and less than or equal to 2.

7. The solar cell according to claim 6, wherein the ratio of the first thickness to the second thickness is 1.025 to 1.

6.

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 2 nm to 50 nm.

9. The solar cell according to claim 8, wherein the difference between the first thickness and the second thickness is 5 nm to 30 nm.

10. The solar cell according to any one of claims 1 to 5, wherein the first thickness is 52 nm to 250 nm, and the second thickness is 50 nm to 200 nm.

11. The solar cell according to claim 10, wherein the first thickness is 55 nm to 230 nm, and the second thickness is 50 nm to 200 nm.

12. The solar cell according to claim 2, wherein in the intermediate region, there is a gap region between the adjacent P-type doped layer and the N-type doped layer, the passivation film layer also covers the gap region, the portion of the passivation film layer located in the gap region has a fifth thickness, and the second thickness is greater than the fifth thickness.

13. The solar cell according to claim 12, wherein in 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 in the spacing region form an integrated continuous structure.

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

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

8.

16. The solar cell according to claim 12, wherein the difference between the second thickness and the fifth thickness is 2 nm to 50 nm.

17. The solar cell according to claim 16, wherein the difference between the second thickness and the fifth thickness is 20 nm to 40 nm.

18. The solar cell according to claim 12, wherein the second thickness is 50 nm to 200 nm, and the fifth thickness is 48 nm to 150 nm.

19. The solar cell according to claim 18, wherein the second thickness is 50 nm to 200 nm, and the fifth thickness is 30 nm to 160 nm.

20. The solar cell according to claim 12, wherein the resistivity of the silicon wafer is greater than 20 Ωcm, and the difference between the second thickness and the fifth thickness is 10 nm to 60 nm.

21. The solar cell according to claim 12, wherein the spacing region is a groove formed on the first surface, 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 located on the side surface of the groove is greater than the thickness of the passivation film layer located on the bottom surface of the groove.

22. The aforementioned solar cell further, The N-type doped layer has a first extended portion that extends above the groove and is suspended above the groove, and the passivation film layer is located at either the end of the first extended portion or on the surface of the first extended portion facing the groove, and the thickness of the passivation film layer located on the surface of the first extended portion facing the groove is greater than the thickness of the passivation film layer located on the bottom surface of the groove. The P-type doped layer has a second extending portion that extends above the groove and is suspended above the groove, and the passivation film layer is located at either the end of the second extending portion or on the surface of the second extending portion facing the groove, and the thickness of the passivation film layer located on the surface of the second extending portion facing the groove is greater than the thickness of the passivation film layer located on the bottom surface of the groove. A solar cell according to claim 21, satisfying at least one of the following conditions.

23. The solar cell according to claim 12, wherein the spacing region is a convex base located between adjacent P-type doped layers and N-type doped layers, the top surface of the convex base is higher than the tops of the P-type doped layer and the N-type doped layer, the passivation film layer is located on either the top surface or the side surface of the convex base, and the thickness of the passivation film layer located on the top surface of the convex base is greater than the thickness of the passivation film layer located on the side surface of the convex base.

24. The portion of the passivation film layer located in the intermediate region includes a first type of passivation sublayer and a second type of passivation sublayer that are laminated together, and the thickness of the passivation film layer located in the intermediate region is the sum of the thicknesses of the first type of passivation sublayer and the second type of passivation sublayer. The solar cell according to claim 2, wherein the thickness of the portion of the first type of passivation sublayer located on the N-type doped layer is greater than the thickness of the portion of the first type of passivation sublayer located on the P-type doped layer.

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

26. The solar cell according to claim 25, wherein the first type of passivation sublayer is manufactured by a PECVD process or a thermal growth process, and the second type of passivation sublayer is manufactured by an atomic deposition process.

27. The solar cell according to any one of claims 24 to 26, wherein the first type of passivation sublayer comprises at least one of a silicon oxide film layer, a silicon nitride film layer, and a silicon oxynitride film layer, and the second type of passivation sublayer comprises an aluminum oxide film layer.

28. The solar cell according to claim 27, wherein the silicon oxide film layer is a multilayer silicon oxide formed by sequential stacking, the silicon nitride film layer is a multilayer silicon nitride formed by sequential stacking, and the silicon oxynitride film layer is a multilayer silicon oxynitride formed by sequential stacking.

29. A battery module characterized by including a solar cell according to any one of claims 1 to 28.

30. A solar power generation system characterized by including the battery module described in claim 29.

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