Solar cell and photovoltaic module

Abstract

The invention provides a solar cell and a photovoltaic module, and relates to the field of photovoltaic technology. The solar cell includes: a semiconductor substrate; the first doping layer and the second doping layer are arranged on the semiconductor substrate and have different doping types; the surface passivation layer is located on the sides, away from the semiconductor substrate, of the first doping layer and the second doping layer; wherein the semiconductor substrate comprises two opposite long edges; the two long edges are respectively a first edge and a second edge; each of the first edge and the second edge comprises a central position and an edge position; the resistivity of the central position of the first edge is R1, the resistivity of the edge position of the first edge is R2, and the resistivity difference value 1 is equal to R2-R1; the resistivity of the central position of the second edge is R3, the resistivity of the edge position is R4, and the resistivity difference value 2 is equal to R4-R3; wherein 1 > 2. According to the invention, the fragment rate and the fill factor are considered, and the performance of the solar cell is improved.

Description

TECHNICAL FIELD

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

[0002] The cut solar cell can effectively reduce the series resistance loss of the solar cell, and thus becomes a mainstream cell for improving the efficiency of the photovoltaic module.

[0003] At present, the production process of the cut solar cell mainly includes: cutting the semiconductor substrate to form the solar cell, or cutting the whole solar cell.

[0004] However, the solar cell formed by the above two processes inevitably has the following problems: the cutting process has a high fragment rate. SUMMARY

[0005] The present application provides a solar cell and a photovoltaic module, which aims to solve the problem of high fragment rate of the existing solar cell.

[0006] In a first aspect, the present application provides a solar cell, comprising:

[0007] a semiconductor substrate;

[0008] a first doped layer and a second doped layer with different doping types arranged on the semiconductor substrate;

[0009] a surface passivation layer located on the side of the first doped layer and the second doped layer away from the semiconductor substrate;

[0010] wherein the semiconductor substrate comprises two opposite long edge edges, the two long edge edges are respectively a first edge and a second edge, and the first edge and the second edge each comprise a center position and an edge position;

[0011] the resistivity of the center position of the first edge is R1, the resistivity of the edge position is R2, and the resistivity difference Δ1=R2-R1; the resistivity of the center position of the second edge is R3, the resistivity of the edge position is R4, and the resistivity difference Δ2=R4-R3; wherein Δ1>Δ2.

[0012] In the present application, the first edge is the newly formed edge after cutting the semiconductor substrate or slicing the cell, and the resistivity variation degree of the first edge directly corresponds to the resistivity variation degree of the original semiconductor substrate on the cutting path. Therefore, by controlling the resistivity variation degree of the first edge after cutting and the resistivity variation degree of the second edge in the non-cutting area, the resistivity variation degree of the original semiconductor substrate on the cutting path can be limited, and thus the fragment rate during cutting of the original semiconductor substrate and the efficiency of the cut cell can be improved.

[0013] The application researches and finds that by controlling the degree of resistivity variation in the semiconductor substrate along the cutting path, controlling the resistivity difference Δ1>Δ2, realizing a greater degree of variation of the doping concentration of the first edge from the center position to the edge position, thereby forming a more significant stress buffer structure. As the degree of variation of the doping concentration increases, more scattering centers are formed in the semiconductor due to defects, and these defects can disperse stress distribution under stress. At the same time, the concentration of the doping element with a large degree of variation plays a greater pinning role, enhancing the stress buffer capacity, and thus the chip rate during cutting of the original semiconductor substrate can be improved.

[0014] At the same time, by controlling the lower Δ2 of the non-cutting area, i.e., the second edge, i.e., the smaller resistivity difference between the center position and the edge position of the second edge, the resistivity is smoothly transitioned from the center position to the edge position, reducing the potential barrier mutation in the carrier transport of the non-cutting edge area, i.e., the second edge, reducing the series resistance, and improving the fill factor. Therefore, the application takes into account the chip rate and the fill factor, and improves the performance of the solar cell.

[0015] In some possible embodiments, the ratio of Δ1 to Δ2 is greater than 1 and less than or equal to 1000.

[0016] In this embodiment, if the ratio of Δ1 to Δ2 is too large, Δ1 is relatively large, the doping concentration of the first edge 131 changes too fast from the edge position to the center position, the process is difficult to implement, and the production efficiency may be significantly reduced; if the ratio of Δ1 to Δ2 is too small, Δ1 is relatively small, the doping concentration gradient is not enough to disperse the cutting stress, the chip rate is still high, and the barrier mutation in the carrier transport is more serious at the second edge 141, and the reduction of the series resistance of the second edge 141 is not good. Therefore, in the application, the ratio of Δ1 to Δ2 is in the above range, which is the result of the optimization balance of process cost, chip rate and series resistance. Not only will it not lead to high process cost, but also the chip rate is low, the series resistance of the non-cutting surface edge 141 is low, and the fill factor is improved.

[0017] In some possible embodiments, the resistance variation rate k1 of the first edge from the edge position to the center position is (R2-R1) / R1; the resistance variation rate k2 of the second edge from the edge position to the center position is (R4-R3) / R3; wherein k1>k2.

[0018] In the embodiment, first, the first edge has a larger resistivity change rate k1, and the resistivity in the first edge rises faster from the center position to the edge position, that is, the doping concentration at the edge position of the first edge changes rapidly from small to large, and a transition region with a high doping concentration is quickly formed, which can disperse the cutting stress through the difference in doping concentration gradient, reduce the risk of embrittlement, and significantly reduce the fragmentation rate. Second, the second edge has a smaller resistivity change rate k2, and the resistivity rises gently from the center position to the edge position, which reduces the barrier mutation in carrier transport and further reduces the area series resistance of the non-cutting surface edge, thereby improving the fill factor.

[0019] In some possible embodiments, the ratio of k1 to k2 is greater than 1 and less than or equal to 100.

[0020] In the embodiment, if the resistivity change rate k1 of the first edge from the edge position to the center position is relatively large, the doping concentration at the edge position of the first edge changes too fast, and the process is difficult to implement, which may significantly reduce the production efficiency. If the resistivity change rate k1 of the first edge from the edge position to the center position is relatively small, the doping concentration gradient difference is not enough to disperse the cutting stress, and the fragmentation rate is still high. In addition, if k2 is relatively large, the barrier mutation in carrier transport in the second edge region (i.e., the non-cutting region) is more serious, and the reduction degree of the non-cutting region series resistance is not good. Therefore, in the present application, the ratio of k1 to k2 is within the above range, which is the result of the optimization balance of process cost, fragmentation rate and series resistance. It not only does not lead to high process cost, but also has low fragmentation rate and low area series resistance of the non-cutting surface edge, thereby improving the fill factor.

[0021] In some possible embodiments, the resistivity on the first edge and the second edge satisfies R2>R1 and R3>R1.

[0022] In some possible embodiments, the resistivity on the first edge and the second edge satisfies R4>R3>R2>R1.

[0023] In the embodiment, the resistivity of the first edge increases from the center position to the edge position, that is, the doping concentration of the first edge decreases from the center position to the edge position, which can reduce the fragmentation rate.

[0024] In the embodiment, since the center position of the first edge is subjected to relatively concentrated force and large torque during cutting, by controlling the resistivity, the doping concentration of the center position of the first edge is increased, which can significantly reduce the fragmentation rate of the center position of the first edge and further reduce the chip rate. At the same time, if the resistivity of the first edge is lower, the recombination rate change before and after cutting can be ensured to be small, thereby reducing the recombination of the cutting edge and improving the passivation effect.

[0025] In some possible embodiments, the region within the first preset distance range from the center position of the first edge is a first region; and the region within the second preset distance range from the center position of the first edge is a second region; wherein the first preset distance range is 0-25 mm, and the second preset distance range is 60-80 mm; the resistivity change rate per unit distance in the first region is greater than the resistivity change rate per unit distance in the second region.

[0026] In the embodiment, the region within the first preset distance range from the center position of the first edge is a main stress region of the first surface and / or the second surface of the semiconductor substrate in the cutting process, and has a relatively high probability of fragments. Therefore, in the application, the resistivity change rate of the region is relatively large, the resistivity change of the region is controlled to be fast, so that the doping concentration of the region changes fast, a transition region with a high doping concentration is quickly formed, the cutting stress is dispersed through the difference in the doping concentration gradient, the risk of embrittlement is reduced, and the fragment rate is obviously reduced.

[0027] In some possible embodiments, the ratio of the average doping concentration of the antimony element in the semiconductor substrate of the first edge to the average doping concentration of the antimony element in the semiconductor substrate of the second edge is 1.02-470.

[0028] In the embodiment, the semiconductor substrate is doped with the antimony element. Since the atomic radius of the antimony element is relatively large compared with the atomic radius of silicon, the crystal structure in the semiconductor substrate can be optimized, and the strength of the material can be improved.

[0029] In some possible embodiments, the doping concentration of the antimony element in the semiconductor substrate is 4E+13 cm -3 -2E+16 cm -3 ; and / or the resistivity of the semiconductor substrate is 0.3-10 Ω·cm or 10-100 Ω·cm.

[0030] In some possible embodiments, the semiconductor substrate contains the antimony element and the phosphorus element; and the mass ratio of the phosphorus element to the antimony element in the semiconductor substrate is greater than 0 and less than or equal to 20.

[0031] In the embodiment, when the semiconductor substrate is doped with the antimony element, since the volatility of the antimony is relatively large and the evaporation rates of the antimony and the phosphorus are different, when the semiconductor substrate is prepared, the resistivity uniformity of the semiconductor substrate can be improved by the combined action of the two dopants.

[0032] In some possible embodiments, the first edge and the second edge are relatively distributed along a first direction; the first direction is the direction from the first edge to the second edge.

[0033] Along the first direction, the antimony concentration in the doped layer located at the first edge is greater than the antimony concentration in the doped layer located at the second edge; and / or,

[0034] Along the first direction, the concentration of antimony in the passivation layer located at the first edge is greater than the concentration of antimony in the passivation layer located at the second edge.

[0035] In some possible embodiments, the first edge and the second edge are distributed relative to each other along a first direction; the resistivity at at least one point on the second edge is greater than the resistivity at a point on the first edge opposite to that point along the first direction.

[0036] In this embodiment, the doping concentration of the points in the first edge is higher, which improves crack resistance and reduces the cracking rate; the second edge belongs to the non-cutting region, and the low doping concentration in the non-cutting region prioritizes the electrical performance, maintains high passivation quality, and reduces on-state voltage loss.

[0037] In some possible embodiments, the first edge and the second edge are distributed relative to each other along a first direction;

[0038] In this embodiment, the antimony concentration in the doped layer located at the first edge is greater than that in the doped layer located at the second edge. Since the first edge corresponds to the cutting path region, the antimony doping concentration is higher, which can effectively fill the dangling bonds at the doped layer interface and suppress further aggravation of defect states, thereby improving the performance of the solar cell.

[0039] In this embodiment, the antimony concentration in the passivation layer located at the first edge is greater than that in the passivation layer located at the second edge. Since the first edge corresponds to the cutting path region, which has more cutting defects, the antimony doping concentration is higher, which enhances the field passivation effect of the passivation layer, reduces recombination losses caused by cutting damage, and improves the performance of the solar cell.

[0040] In some possible embodiments, the average resistivity of the first edge is less than the average resistivity of the second edge.

[0041] In some possible embodiments, the ratio of the average resistivity of the first edge to the average resistivity of the second edge is 1.2 to 350.

[0042] In some possible embodiments, the semiconductor substrate includes opposing first and second surfaces, and a side surface connecting the first and second surfaces;

[0043] The solar cell further includes a passivation layer disposed on the side surface; the passivation layer on the side surface near the first edge is a first passivation layer; the passivation layer on the first surface is a surface passivation layer; wherein the thickness of the first passivation layer is greater than the thickness of the surface passivation layer.

[0044] In this embodiment, the side closest to the first edge is the cutting surface, and the thickness of the first passivation layer is greater than the thickness of the surface passivation layer, which can improve the cutting defects of the cutting surface, reduce carrier recombination, and improve battery efficiency.

[0045] In some possible embodiments, in the solar cell, the first doped layer and the second doped layer are both located on the same side of the semiconductor substrate along the thickness direction of the semiconductor substrate; or, the first doped layer and the second doped layer are located on different sides of the semiconductor substrate along the thickness direction of the semiconductor substrate.

[0046] In some possible embodiments, the semiconductor substrate further includes two opposing short edges; at least one of the long edges has a length of b, and at least one of the short edges has a length of a; 1.6 < b / a ≤ 8.

[0047] A second aspect of this application provides a photovoltaic module, comprising:

[0048] A battery string, wherein the battery string is composed of a plurality of solar cells connected together as described above;

[0049] An encapsulation layer is used to cover the surface of the battery string;

[0050] A cover plate is used to cover the surface of the encapsulation layer away from the battery string.

[0051] In some possible embodiments, the number of solar cells distributed opposite to each other along a first direction at the first edge and the second edge accounts for 20% to 100% of the total number of solar cells in the photovoltaic module.

[0052] The aforementioned solar cells and photovoltaic modules have the same or similar beneficial effects, and will not be repeated here to avoid repetition. Attached Figure Description

[0053] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0054] Figure 1 , Figure 2 and Figure 6The following are schematic diagrams illustrating the structures of two types of solar cells in embodiments of this application;

[0055] Figures 3 to 5 A schematic diagram showing the resistivity distribution at various points on several first surfaces of a solar cell according to embodiments of this application is illustrated.

[0056] Explanation of the attached drawing numbers:

[0057] 1-Semiconductor substrate, 2-First doped layer, 3-Second doped layer, 31-First side surface, 32-Second side surface, 4-Surface passivation layer, 41-Third side surface, 42-Fourth side surface, 5-First collector electrode, 6-Second collector electrode, 7-Tunneling layer, 11-First surface, 111-Geometric center of the first surface, 12-Second surface, 13-Cut surface, 14-Uncut surface, 131-First edge, 141-Second edge, 1311-Center position of the first edge, 1312-Edge position of the first edge, 1313-Middle position of the first edge, 1411-Center position of the second edge, 1412-Edge position of the second edge, 8-First passivation layer. Detailed Implementation

[0058] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0059] This application provides a solar cell, with reference to... Figures 1 to 2 The solar cell includes a semiconductor substrate 1, a first doped layer 2, a second doped layer 3, and a surface passivation layer 4. It may also include a first current collector 5 and a second current collector 6. The semiconductor substrate 1 can be N-type or P-type monocrystalline silicon, providing long-lived charge carriers. For example, the semiconductor substrate 1 is N-type monocrystalline silicon. The semiconductor substrate 1 includes a first surface 11 and a second surface 12 opposite each other along the thickness direction L1 of the semiconductor substrate 1, and a side surface connecting the first surface 11 and the second surface 12. The side surface includes a diced surface 13 and a non-diced surface 14. Of the first surface 11 and the second surface 12, one is a light-facing surface and the other is a backlighting surface. During the operation of the solar cell, the side of the semiconductor substrate 1 that mainly receives light is its light-facing surface, while the backlighting surface is opposite to the light-facing surface. For example, Figure 2 In the semiconductor substrate 1, the second surface 12 is its backlight surface, and the first surface 11 is its light-facing surface.

[0060] The first doped layer 2 and the second doped layer 3 are located along the thickness direction L1 of the semiconductor substrate 1, at least on one of the first surface 11 and the second surface 12 of the semiconductor substrate 1. For example, Figure 1 In this example, the first doped layer 2 and the second doped layer 3 are located on different sides of the semiconductor substrate 1, forming a bifacial solar cell. For another example, Figure 2 In this configuration, the first doped layer 2 and the second doped layer 3 are both located on the same side of the semiconductor substrate 1, forming a back-contact solar cell. For example, Figure 1 This is merely an illustration of the first doped layer 2 and the second doped layer 3 located on the surface of the semiconductor substrate; of course, the first doped layer 2 or the second doped layer 3 can also be located inside the semiconductor substrate, for example, by diffusion of doping elements into the substrate to form a doped layer.

[0061] The first doped layer 2 and the second doped layer 3 have different doping types; one is an N-type doped layer and the other is a P-type doped layer. This can be because the first doped layer 2 is a P-type doped layer and the second doped layer 3 is an N-type doped layer, or vice versa. The P-type doped layer can contain one or more elements from Group IIIA (e.g., boron). The N-type doped layer can contain one or more elements from Group VA (e.g., phosphorus, antimony). The materials of the second doped layer 3 and the first doped layer 2 can include any semiconductor material such as silicon, germanium-silicon, germanium, or gallium arsenide. In terms of the arrangement of matter, the crystal phase of the doped layer can be amorphous, microcrystalline, nanocrystalline, single-crystal, or polycrystalline. The materials of the second doped layer 3 and the first doped layer 2 can be the same or different. For example, both the second doped layer 3 and the first doped layer 2 can be doped polycrystalline silicon. For example, the material of the first doped layer 2 may include doped polycrystalline silicon, and the material of the second doped layer 3 may include at least one of doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon. The first doped layer 2 can be obtained by in-situ doping on the surface of the semiconductor substrate or by non-in-situ doping on the surface of the semiconductor substrate. Similarly, the second doped layer 3 can also be obtained by in-situ doping on the surface of the semiconductor substrate or by non-in-situ doping on the surface of the semiconductor substrate. For example, the first doped layer 2 can be disposed on the semiconductor substrate by in-situ doping. As another example, the first doped layer 2 can be deposited on the surface of the semiconductor substrate (e.g., it can be an epitaxial doped layer).

[0062] A surface passivation layer 4 is disposed on the side of the second doped layer 3 and the first doped layer 2 away from the semiconductor substrate 1. In the thickness direction L1 of the semiconductor substrate 1, the doped layer is located between the semiconductor substrate 1 and the surface passivation layer 4.

[0063] The first collector electrode 5 is located on the side of the first doped layer 2 away from the semiconductor substrate 1. The first collector electrode 5 extends through the surface passivation layer 4 into the first doped layer 2 and forms an ohmic contact with the first doped layer 2. The first collector electrode 5 can collect charge carriers and conduct current. The second collector electrode 6 is located on the side of the second doped layer 3 away from the semiconductor substrate 1. The second collector electrode 6 extends through the surface passivation layer 4 into the second doped layer 3 and forms an ohmic contact with the second doped layer 3. The second collector electrode 6 can collect charge carriers and conduct current.

[0064] The cut surface 13 mentioned in this application refers to the newly generated surface during the process of cutting a whole solar cell or a whole semiconductor substrate into sliced ​​solar cells or sliced ​​semiconductor substrates. The cutting process will cause thermal ablation and mechanical damage to the cut surface, forming high-density defects, which leads to a significant increase in the carrier recombination rate. The non-cut surface 14 is the original side surface of the whole solar cell or the original side surface of the whole semiconductor substrate. The non-cut surface 14 here can also be a surface formed by cutting silicon rods or the like with diamond wire. It should be noted that the solar cell mentioned in this application can be a solar cell formed by cutting the whole semiconductor substrate, or a solar cell formed by slicing a whole solar cell. Both are within the protection scope of this application.

[0065] The first surface 11 and the second surface 12 of the semiconductor substrate 1 may include long and short sides, which intersect. The included angle between the long and short sides is not limited; for example, they may be perpendicular to each other, and the length of the long side is greater than the length of the short side. The first edge and the second edge are two edge regions on the first surface 11 or the second surface 12 that include the long side. Specifically, taking the first surface as an example, the first edge 131 is the edge region of the first surface 11 near the cut surface along the long side. The width of the first edge 131 in the direction perpendicular to the long side is not limited; for example, the first edge 131 may be a region extending 2 cm inward from the long side of the first surface 11 near the cut surface along a first direction. The second edge 141 is the edge region of the first surface 11 near the long side that is not cut. The second edge 141 includes the long side of the first surface 11 near the non-cut surface. The width of the second edge 141 in the direction perpendicular to the long side is not limited. For example, the second edge 141 can be a region extending 2 cm inward from the long side of the first surface 11 near the non-cut surface. Exemplarily, the region extending 2 cm inward from the long side of the first surface 11 near the non-cut surface can be a region extending 2 cm towards the center of the semiconductor substrate, parallel to the first direction, starting from the long side of the first surface 11 near the non-cut surface.

[0066] Reference Figures 3 to 5The first surface 11 and / or the second surface include two opposing long edges, namely a first edge 131 and a second edge 141. In this embodiment, the first surface 11 is used as an example for explanation. Both the first edge 131 and the second edge 141 on the first surface include a center position and an edge position. The first edge 131 is the newly formed edge region after cutting the semiconductor substrate or segmenting the battery. The second edge 141 is the original edge of the semiconductor substrate or segmented battery.

[0067] This application, through research and statistics, found that the main reason for the high fragmentation rate of solar cells after cutting in related technologies is that stress is concentrated on the cutting path where the cutting surface 13 is located, especially the stress generated by the torque at the first edge, which is more significant, leading to a significant increase in the fragmentation rate.

[0068] To address the aforementioned technical problems, this application refers to... Figures 3 to 4 The resistivity of the center position 1311 of the first edge is R1, and the resistivity of the edge position 1312 of the first edge is R2, Δ1 = R2 - R1. The resistivity of the center position 1411 of the second edge is R3, and the resistivity of the edge position 1412 of the second edge is R4, Δ2 = R4 - R3; where Δ1 > Δ2.

[0069] Specifically, this application found that by controlling Δ1 > Δ2, the doping concentration variation is greater from the center to the edge of the first edge, resulting in a more significant stress buffer structure, improved crack resistance, and reduced probability of cracking, particularly at the first edge, on the cut surface 13, thus lowering the cracking rate. Furthermore, this application found that the lower Δ2 of the second edge 141 in this application allows for a smoother transition of resistivity from the center to the edge, reducing barrier abrupt changes in carrier transport, lowering series resistance, and improving the fill factor. Therefore, this application also balances the fragmentation rate and fill factor, improving the performance of the solar cell.

[0070] It should be noted that, for example, taking the first surface as an example, the edge position 1312 of the first edge is the position close to the short side along the extension direction of the long side; refer to Figure 3 When the first surface 11 and the second surface are square without chamfers, the edge position 1312 of the first edge can be the endpoint on the first surface 11; refer to Figure 4When the first surface 11 and the second surface are square with chamfers, the edge position 1312 of the first edge can be: the start position of the chamfer on the first edge 131, the end position of the chamfer on the first edge 131, or any point between the start and end positions of the chamfer on the first edge 131. The center position 1311 of the first edge is the set of midpoints along the extension direction of the long side of the first edge 131. The center position 1411 of the second edge can be determined in the same way as the center position 1311 of the first edge, and the edge position 1412 of the second edge can be determined in the same way as the edge position 1312 of the first edge. To avoid repetition, it will not be described again here.

[0071] It should be noted that, for a cut surface 13, it has one first edge 131 corresponding to the first surface 11 and one first edge 131 corresponding to the second surface 12, for a total of two first edges 131: (Refer to...) Figure 3 and Figure 4 R1 and R2 can be the resistivity at the center and the resistivity at the edge of the same first edge 131, which is either of the two first edges 131 mentioned above; or, R1 can be the average of the two resistivities at the two center positions of the two first edges 131, and R2 can be the average of the two resistivities at the two edge positions of the two first edges 131; or, R1 can be the resistivity at the center of one of the two first edges 131, and R2 can be the resistivity at the edge position of the other of the two first edges 131. For a cut surface 13, if it has two first edges 131, one corresponding to a first edge 131 of the first surface 11 and one corresponding to a first edge 131 of the second surface 12, the determination of R1 and R2 includes, but is not limited to, the aforementioned methods. The determination of R3 and R4 corresponding to the second edge 131 is similar or the same, and will not be repeated here to avoid repetition.

[0072] It should be noted that the resistivity measurements at the aforementioned locations can be performed using a resistance meter or similar instrument; the specific measurement method is not limited. A predetermined area of ​​a specific location can be selected, and the resistivity at any point within that area can be measured as the resistivity at that location. Alternatively, the resistivity at any two or more points within that area can be measured, and the arithmetic mean can be calculated as the resistivity at that location. The size of the predetermined area is not limited. For example, it could be 0.1cm × 0.1cm, 0.2cm × 0.5cm, 0.5cm × 0.5cm, etc. The methods for measuring resistivity at other locations are similar or identical, and will not be repeated here to avoid repetition. Figures 3 to 5The black dots marked at each location are only to indicate the corresponding location and do not represent any unevenness or other features at that location.

[0073] It should be noted that the control of different edge resistivity can be achieved using the methods described in the examples below. For instance, ① one method is to perform heat treatment and gettering along the cutting path in the original semiconductor substrate to control the resistivity change along the path; or ② to control the resistivity of different regions through doping treatment; or ③ to control the distribution of the crystal growth liquid surface during silicon rod fabrication, such as controlling the pulling speed, crucible rotation, etc., to control the depth of the solid-liquid interface, thereby controlling the resistivity distribution of different regions of the silicon rod. After the silicon rod is cut into silicon wafers, it will possess this characteristic. The control methods for different edge resistivity in this application include, but are not limited to, the methods described above. The control methods for resistivity at different locations in this application may also include, but are not limited to, the methods described above. To avoid repetition, they will not be elaborated further.

[0074] In some possible embodiments, the ratio of Δ1 to Δ2 is greater than 1 and less than or equal to 1000. Specifically, if the ratio of Δ1 to Δ2 is too large, Δ1 is relatively too large, and the doping concentration change from the edge position 1312 to the center position of the first edge is too rapid, making the process difficult to implement and potentially significantly reducing production efficiency; if the ratio of Δ1 to Δ2 is too small, Δ1 is relatively too small, and the difference in doping concentration gradient is insufficient to disperse the cutting stress, resulting in a still high fragmentation rate. Moreover, if Δ2 is relatively too large, the potential barrier change in carrier transport at the second edge 141 is more severe, and the reduction in the series resistance of the second edge 141 region is not satisfactory. Therefore, in this application, the ratio of Δ1 to Δ2 within the above range is the result of an optimized balance between process cost, fragmentation rate, and series resistance. It not only avoids excessively high process costs but also results in a lower fragmentation rate and a lower series resistance in the second edge 141 region, thereby improving the fill factor.

[0075] For example, the ratio of △1 to △2 can be 1.1, 1.5, 2, 3, 4, 5, 8, 10, 12, 15, 20, 30, 50, 60, 80, 100, 120, 150, 200, 250, 300, 400, 500, 600, 700, 800, 900, or 1000.

[0076] Furthermore, the ratio of △1 to △2 can be greater than 1 and less than or equal to 50, which can further reduce the process cost.

[0077] In some possible embodiments, Δ1 can be 1-10 Ω·cm (ohm·cm), and Δ2 can be 0.01-5 Ω·cm. Both fall within their respective ranges, exhibiting high compatibility with existing solar cell fabrication processes, ease of implementation, low fragmentation rate, and low series resistance in the region of the second edge 141, thus improving the fill factor. For example, Δ1 can be 1 Ω·cm, 1.3 Ω·cm, 1.5 Ω·cm, 1.8 Ω·cm, 2 Ω·cm, 2.3 Ω·cm, 2.5 Ω·cm, 3 Ω·cm, 3.5 Ω·cm, 4 Ω·cm, 4.5 Ω·cm, 5 Ω·cm, 5.5 Ω·cm, 6 Ω·cm, 6.5 Ω·cm, 7 Ω·cm, 7.5 Ω·cm, 8 Ω·cm, 8.5 Ω·cm, 9 Ω·cm, 9.5 Ω·cm, or 10 Ω·cm. For example, △2 here can be 0.01Ω.cm, 0.03Ω.cm, 0.05Ω.cm, 0.08Ω.cm, 0.1Ω.cm, 0.13Ω.cm, 0.15Ω.cm, 0.2Ω.cm, 0.23Ω.cm, 0.25Ω.cm, 0.3Ω.cm, 0.5Ω.cm, 0.65Ω.cm, 0.7Ω.cm, 0.9Ω.cm, 1Ω.cm, 1.3Ω.cm, 1.5Ω.cm, 1.8Ω.cm, 2Ω.cm, 2.3Ω.cm, 2.5Ω.cm, 3Ω.cm, 3.5Ω.cm, 4Ω.cm, 4.5Ω.cm, or 5Ω.cm. It should be noted that the values ​​of △1 and △2 must satisfy the aforementioned size and proportional relationships.

[0078] In some possible embodiments, refer to Figure 1 and Figure 2 The solar cell may also include a tunneling layer 7 located between the doped layer and the semiconductor substrate to improve the passivation contact effect.

[0079] In some possible embodiments, refer to Figure 3 and Figure 4The resistivity change rate from the edge position to the center position of the first edge 131 is k1 = (R2 - R1) / R1, and the resistivity change rate from the edge position to the center position of the second edge 141 is k2 = (R4 - R3) / R3, where k1 > k2. Specifically, firstly, the resistivity change rate k1 from the edge position to the center position of the first edge 131 is larger, and the resistivity in the first edge 131 increases faster from the center position to the edge position. This causes the doping concentration at the edge position 1312 to the center position of the first edge to increase rapidly from a small value to a large value, quickly forming a transition region with a higher doping concentration. This can disperse the cutting stress through the difference in doping concentration gradient, reduce the risk of embrittlement, and significantly reduce the fragmentation rate. Secondly, the resistivity change rate k2 from the edge position to the center position of the second edge 141 is smaller, and the resistivity increases gradually from the center position 1411 to the edge position of the second edge. This reduces the potential barrier abrupt change in carrier transport, further reducing the regional series resistance of the second edge 141 and improving the fill factor.

[0080] In some possible embodiments, the ratio of k1 to k2 is greater than 1 and less than or equal to 100. Specifically, if this ratio is too large, it means that k1 is relatively too large, the doping concentration changes too rapidly from the edge position 1312 to the center position of the first edge, making the process difficult to implement and potentially significantly reducing production efficiency; if this ratio is too small, k1 is relatively too small, the difference in doping concentration gradient is insufficient to disperse the cutting stress, the fragmentation rate is still high, and k2 is relatively too large, the potential barrier change in carrier transport at the second edge 141 is more severe, and the reduction in the series resistance of the second edge 141 region is not good. Therefore, in this application, the ratio of k1 to k2 is within the above range, which is the result of optimizing the balance between process cost, fragmentation rate and series resistance. It not only does not lead to excessively high process cost, but also results in a low fragmentation rate and a low series resistance of the second edge 141 region, thus improving the fill factor.

[0081] For example, the ratio of k1 to k2 can be 1.1, 1.5, 2, 3, 4, 5, 8, 10, 12, 15, 20, 30, 50, 60, 80, or 100.

[0082] Furthermore, the ratio of k1 to k2 can be greater than 1 and less than or equal to 20, which can further reduce process costs.

[0083] In some possible embodiments, k1 is 10%-50% and k2 is 0.5%-10%, both falling within corresponding ranges. This approach offers high compatibility with existing solar cell fabrication processes, ease of implementation, low fragmentation rate, and low series resistance in the second edge 141 region, thereby improving the fill factor. For example, k1 can be 10%, 11%, 15%, 18%, 20%, 22%, 25%, 27%, 30%, 33%, 35%, 39%, 40%, 41%, 45%, 47%, or 50%. For example, k2 can be 0.5%, 0.8%, 0.9%, 1%, 1.2%, 1.5%, 1.7%, 2%, 2.5%, 2.9%, 3%, 3.5%, 3.7%, 4%, 4.5%, 5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.8%, 8%, 8.3%, 9%, 9.7%, or 10%. It should be noted that the values ​​of k1 and k2 must satisfy the aforementioned size and proportional relationships.

[0084] In some possible embodiments, R2 > R1, indicating that the resistivity of the first edge 131 increases from the center to the edge, meaning the doping concentration of the first edge 131 decreases from the center to the edge, which can reduce the fragmentation rate. R3 > R1, indicating that the resistivity of the center position 1311 of the first edge is lower, and the doping concentration of the center position 1311 of the first edge is higher. Since the center position 1311 of the first edge experiences concentrated force and larger torque during the cutting process, controlling its resistivity and increasing the doping concentration of the center position 1311 of the first edge can significantly reduce the fragmentation rate of the center position 1311, further reducing the chipping rate. Simultaneously, the lower resistivity of the first edge 131 ensures a smaller change in the recombination rate before and after cutting, thereby reducing recombination at the first edge 131 and improving the passivation effect.

[0085] In some possible embodiments, in the first edge 131: the resistivity increases at each point from the center position to the edge position, that is, the doping concentration decreases at each point from the center position to the edge position, and the resistivity increases sequentially, thereby forming a gradual gradient of mechanical strength from high to low from the center position to the edge position, so that the stress is released step by step from the center position to the edge position, avoiding the stress abruptly at a single interface, and further reducing the cracking rate.

[0086] In some possible embodiments, refer to Figure 3 and Figure 4The first edge 131 further includes: a middle position, located midway between the center position and the edge position along the extension direction of the aforementioned long side; the resistivity of the middle position 1313 of the first edge is R5; R2 > R5 > R1. From the center position to the edge position, the resistivity of the first edge 131 increases sequentially, and the doping concentration at each point decreases, thus forming a gradual gradient of mechanical strength from high to low from the center position to the edge position. This allows stress to be released step-by-step from the center position to the edge position, avoiding abrupt stress changes at a single interface and further reducing the cracking rate. The middle position 1313 of the first edge is the midpoint between the center position and the edge position of the first edge 131.

[0087] In some possible embodiments, R4 > R3 > R2 > R1, meaning that the resistivity of the first edge 131 increases from the center to the edge, indicating that the doping concentration of the first edge 131 decreases from the center to the edge. Furthermore, the doping concentration at the center of the first edge 1311 is relatively higher, which can further reduce the fragmentation rate at the center of the first edge 1311, thus further reducing the splitting rate. Additionally, the resistivity difference between the center and edge of the second edge is smaller, resulting in a smoother transition of resistivity from the center to the edge of the second edge. This reduces abrupt changes in the potential barrier during carrier transport, lowers the series resistance, and further improves the fill factor. Simultaneously, the lower resistivity of the first edge 131 ensures a smaller change in the recombination rate before and after dicing, thereby reducing recombination at the first edge 131 and improving the passivation effect.

[0088] In some possible embodiments, refer to Figure 3 and Figure 4 The resistivity at the geometric center of the first surface 11 and / or the second surface (such as the geometric center 111 of the first surface) is R6; the first edge 131 also includes a middle position, located midway between the center position and the edge position along the extension direction of the aforementioned long side; the resistivity at the middle position is R5; R6 ≥ R5. That is, relative to the geometric center of the first surface 11 and / or the second surface, the resistivity at the middle position 1313 of the first edge is lower and the doping concentration is higher, further reducing the probability of fragmentation of the first edge 131. At the same time, the lower resistivity of the first edge 131 ensures a smaller change in the recombination rate before and after cutting, thereby reducing recombination at the first edge 131 and improving the passivation effect.

[0089] In some possible embodiments, refer to Figure 5 In the first surface 11 and / or the second surface: the area at a first preset distance from the center position 1311 of the first edge is the first area ( Figure 5 The area shown by the innermost dashed semicircle), the first preset distance is 0-25mm (i.e., Figure 5The innermost dotted semicircle has a maximum radius of 25mm. In the first surface 11 and / or the second surface: the area at a second preset distance from the center position 1311 of the first edge is the second area. Figure 5 The area indicated by the dashed semicircle in the shaded area), the second preset distance is 60-80mm (i.e., Figure 5 The inner radius of the dashed semicircle shown in the shaded area is 60mm. Figure 5 The outermost radius of the shaded dashed semicircle is 80mm. The rate of change of resistance per unit distance in the first region is greater than that in the second region. This unit distance can be 0.1mm, 0.5mm, 1mm, etc., and is not limited thereto. The unit distances in the first and second regions are equal. Within the second region, the resistance at a point on the inner side of the same radius is R7, and the resistance at a point on the same radius at a distance of one unit distance from R7 is R8. The rate of change of resistance per unit distance in the second region is (R8-R7) / R7. Within the first region, the resistance at a point on the inner side of the same radius is R9, and the resistance at a point on the same radius at a distance of one unit distance from R9 is R10. The rate of change of resistance per unit distance in the first region is (R10-R9) / R9. Specifically, in the first surface 11 and / or the second surface: the area at the first preset distance from the center position 1311 of the first edge is the main stress area of ​​the first surface 11 and / or the second surface during the cutting process, and has a relatively high probability of fragmentation. Therefore, in this application, the resistance change rate of the first region is large, indicating that the resistivity of the first region changes rapidly and the doping concentration of the first region changes rapidly, quickly forming a transition region with a high doping concentration. The cutting stress can be dispersed by the difference in doping concentration gradient, reducing the risk of embrittlement and significantly reducing the fragmentation rate.

[0090] For example, the first preset distance mentioned above can be: 1mm, 13mm, 15mm, 18mm, 20mm, 21mm, or 25mm. The second preset distance mentioned above can be: 60 to 62mm, 60 to 63mm, 60 to 65mm, 60 to 67mm, 60 to 68mm, 60 to 69mm, 60 to 70mm, 60 to 73mm, 60 to 75mm, 60 to 78mm, or 60 to 80mm. In some possible embodiments, refer to... Figures 3 to 5 The cutting surface 13 and the non-cutting surface 14 are distributed relative to each other along the first direction L2, which is compatible with the existing cutting process and requires little process improvement.

[0091] In some possible embodiments, the cut surface 13 and the non-cut surface 14 are relatively distributed along the first direction L2, with reference to Figure 5The resistivity R11 at at least one point on the second edge 141 is greater than the resistivity R12 at a point on the first edge 131 opposite that point along the first direction L2. That is, at the points on the first edge 131 and the second edge 141 opposite each other along the first direction L2, the doping concentration of the points on the first edge 131 is higher. This higher doping concentration on the first edge 131 improves crack resistance and reduces the breakage rate. The second edge 141, located in the non-cutting surface, has a lower doping concentration that prioritizes electrical performance, maintains high passivation quality, and reduces on-state voltage loss. Simultaneously, the lower resistivity of the first edge 131 ensures a smaller change in the recombination rate before and after cutting, thereby reducing recombination at the cut edge and improving the passivation effect.

[0092] It should be noted that for the point pairs of the first edge 131 and the second edge 141 that are opposite each other along the first direction L2, it is only necessary to ensure that they are located in the first edge 131 and the second edge 141 respectively, and are opposite each other along the first direction L2. The specific positions are not limited. The specific doping concentration difference is not limited.

[0093] In some possible embodiments, based on the relative distribution of the cut surface 13 and the non-cut surface 14 along the first direction L2, the concentration of antimony in the doped layer located at the first edge along the first direction is greater than the concentration of antimony in the doped layer located at the second edge. On the one hand, the radius of antimony atoms is larger, which can further enhance the strength of the doped layer at the first edge and reduce the fragmentation rate of the doped layer at the first edge; on the other hand, the higher concentration of antimony in the doped layer located at the first edge can effectively fill the dangling bonds at the interface and suppress the further aggravation of defect states, thereby improving the performance of the solar cell.

[0094] It should be noted that the antimony concentration in the doped layer at the first edge refers to the antimony concentration at any point in the doped layer covering the first edge, or the arithmetic mean of the antimony concentrations at any two, three, four, etc., points in the doped layer covering the first edge. The antimony concentration in the doped layer at the second edge is determined in a similar manner to that in the doped layer at the first edge.

[0095] In some possible embodiments, based on the relative distribution of the cut surface 13 and the non-cut surface 14 along the first direction L2, the antimony concentration in the passivation layer at the first edge is greater than the antimony concentration in the passivation layer at the second edge along the first direction. On the one hand, the radius of antimony atoms is larger, which can further enhance the strength of the passivation layer at the first edge and reduce the fragmentation rate of the passivation layer at the first edge; on the other hand, the higher antimony concentration in the passivation layer at the first edge can effectively fill the dangling bonds at the interface and suppress the further aggravation of defect states, thereby improving the performance of the solar cell.

[0096] It should be noted that the antimony concentration in the passivation layer at the first edge refers to the antimony concentration at any point within the passivation layer covering the first edge, or the arithmetic mean of the antimony concentrations at any two, three, four, or more points within the passivation layer covering the first edge. The antimony concentration in the passivation layer at the second edge is determined in a similar manner to that at the first edge. Here, passivation primarily refers to the surface passivation layer.

[0097] In some possible embodiments, the second doped layer 3 contains antimony, based on the relative distribution of the cut surface 13 and the non-cut surface 14 along the first direction L2; refer to Figure 1 The second doped layer 3 includes a first side surface 31 adjacent to the diced surface 13 and a second side surface 32 adjacent to the non-diced surface 14 along the thickness direction L1 of the semiconductor substrate 1. The antimony doping concentration at at least one point on the first side surface 31 is greater than the antimony doping concentration at a point on the second side surface 32 opposite that point along the first direction L2. On one hand, the larger radius of antimony atoms further enhances the strength of the second doped layer 3, suppressing the generation of microcracks in the second doped layer 3 and thus reducing the risk of fragmentation during subsequent cell cutting. On the other hand, at the points adjacent to the diced surface 13 and the second side surface 32 along the first direction L2, the antimony doping concentration at the point adjacent to the diced surface 13 is higher, effectively filling dangling bonds at the interface and suppressing further aggravation of defect states, thereby improving the performance of the solar cell.

[0098] It should be noted that for the point pairs of the first side 31 and the second side 32 that are opposite each other along the first direction L2, it is only necessary to ensure that they are located in the first side 31 and the second side 32 respectively, and are opposite each other along the first direction L2. The specific positions are not limited. The specific doping concentration difference is not limited.

[0099] In some possible embodiments, based on the relative distribution of the cut surface 13 and the non-cut surface 14 along the first direction L2, the surface passivation layer 4 contains antimony. Antimony atoms have a larger radius, which can further enhance the strength of the surface passivation layer 4, suppress the generation of microcracks in the surface passivation layer 4, and thus reduce the risk of fragmentation in the subsequent cell cutting process; (Refer to...) Figure 1The surface passivation layer 4 includes: a third side surface 41 adjacent to the diced surface 13 and a fourth side surface 42 adjacent to the non-diced surface 14 in the thickness direction L1 of the semiconductor substrate 1; the antimony doping concentration at at least one point on the third side surface 41 is greater than the antimony doping concentration at a point on the fourth side surface 42 opposite to that point along the first direction L2. In the thickness direction L1 of the semiconductor substrate 1, the antimony doping concentration at the points adjacent to the third side surface 41 of the diced surface 13 and the fourth side surface 42 of the non-diced surface 14 opposite to each other along the first direction L2 is higher, which enhances the field passivation effect, reduces recombination loss caused by dicing damage, and improves the performance of the solar cell.

[0100] It should be noted that for the point pairs of the third side 41 and the fourth side 42 that are opposite each other along the first direction L2, it is only necessary to ensure that they are located in the third side 41 and the fourth side 42 respectively, and are opposite each other along the first direction L2. The specific positions are not limited. The specific doping concentration difference is not limited.

[0101] In some possible embodiments, the semiconductor substrate of the first edge 131 and the semiconductor substrate of the second edge 141 contain antimony. Antimony atoms have a larger radius, which can further enhance the strength of the first edge 131 and the second edge 141 and reduce the fragmentation rate.

[0102] In some possible embodiments, the ratio of the average antimony doping concentration in the semiconductor substrate of the first edge 131 to the average antimony doping concentration in the semiconductor substrate of the second edge 141 is between 1.02 and 470. This means the average antimony doping concentration in the semiconductor substrate of the first edge 131 is higher. The high antimony doping in the semiconductor substrate of the first edge 131 improves crack resistance, meets dicing requirements, and reduces the dicing rate. The semiconductor substrate of the second edge 141 is located in the non-dicing region, and electrical performance must be prioritized. Therefore, the semiconductor substrate of the second edge 141 has low antimony doping to maintain high passivation quality and reduce on-state voltage loss. Furthermore, if this ratio is too small, the reduction in dicing rate will not be significant. If this ratio is too large, the antimony doping process becomes more complex, leading to higher process costs. Therefore, this ratio, within this range, can not only significantly reduce the dicing rate but also avoid increasing process costs. Simultaneously, the aforementioned doping concentration relationship allows for lower resistivity in the first edge 131, ensuring a smaller change in recombination rate before and after dicing, thereby reducing recombination at the dicing edge and improving the passivation effect.

[0103] For example, the ratio of the average doping concentration of antimony in the semiconductor substrate of the first edge 131 to the average doping concentration of antimony in the semiconductor substrate of the second edge 141 is 1.02, 1.04, 1.05, 1.1, 1.15, 1.2, 1.25, 1.5, 1.8, 2, 5, 10, 20, 30, 50, 60, 80, 100, 150, 180, 200, 250, 300, 350, 400, 450, 470.

[0104] It should be noted that the average doping concentration of antimony in the semiconductor substrate of the first edge 131 refers to the arithmetic mean of the doping concentration of antimony at any two points, the arithmetic mean of the doping concentration of antimony at any three points, the arithmetic mean of the doping concentration of antimony at any four points, and so on; or, the average doping concentration of antimony in the semiconductor substrate of the first edge 131 refers to the average of the doping concentration of antimony at the aforementioned middle, center, and edge positions in the semiconductor substrate of the first edge 131. The method for determining the average doping concentration of antimony in the semiconductor substrate of the second edge 141 is the same as or similar to the method for determining the average doping concentration of antimony in the semiconductor substrate of the first edge 131, and will not be repeated here to avoid repetition.

[0105] In some possible embodiments, based on the relative distribution of the diced surface 13 and the non-diced surface 14 along the first direction L2, both the semiconductor substrate of the first edge 131 and the semiconductor substrate of the second edge 141 contain antimony. The doping concentration of antimony at at least one point on the semiconductor substrate of the first edge 131 is greater than the doping concentration of antimony at a point on the semiconductor substrate of the second edge 141 opposite to that point along the first direction. This can reduce the fragmentation rate of the first edge 131 and maintain the high passivation quality of the second edge 141, thereby reducing the on-state voltage loss.

[0106] In some possible embodiments, the average antimony doping concentration in the semiconductor substrate of the first edge 131 may be 4.5E+13cm. -3 Up to 2E+16cm -3 The average doping concentration of antimony in the semiconductor substrate at the first edge 131 is suitable, which can significantly reduce the chipping rate without increasing the processing cost. For example, the average doping concentration of antimony in the semiconductor substrate at the first edge 131 can be 4.5E+13cm. -3 4.9E+13cm -3 5E+13cm -3 8E+13cm -3 1E+14cm -3 3E+14cm -3 4.5E+14cm-3 5E+14cm -3 7.5E+14cm -3 8E+14cm -3 9E+14cm -3 1E+15cm -3 2E+15cm -3 3.5E+15cm -3 5E+15cm -3 8E+15cm -3 9E+15cm -3 1E+16cm -3 2E+16cm -3 .

[0107] In some possible embodiments, the resistivity of the semiconductor substrate at the first edge 131 can be 0.3-90 Ω·cm, which can not only significantly reduce the cleavage rate but also avoid increasing the process cost.

[0108] In some possible embodiments, the average antimony doping concentration in the semiconductor substrate of the second edge 141 may be 4.3E+13cm. -3 Up to 1.6E+16cm -3 The average antimony doping concentration in the semiconductor substrate of the second edge 141 is suitable, maintaining high passivation quality and reducing turn-on voltage loss. For example, the average antimony doping concentration in the semiconductor substrate of the second edge 141 can be 4.3E+13cm. -3 4.5E+13cm -3 5E+13cm -3 8E+13cm -3 1E+14cm -3 3E+14cm -3 4.5E+14cm -3 5E+14cm -3 7.5E+14cm -3 8E+14cm -3 9E+14cm -3 1E+15cm -3 2E+15cm -3 3.5E+15cm -3 5E+15cm -3 8E+15cm -3 9E+15cm -3 1E+16cm -3 1.6E+16cm -3 .

[0109] In some possible embodiments, the resistivity of the semiconductor substrate of the second edge 141 can be 0.4-100 Ω·cm, which also maintains high passivation quality and reduces on-state voltage loss.

[0110] In some possible embodiments, the average resistivity of the first edge 131 is lower than the average resistivity of the second edge 141. The lower average resistivity of the first edge 131 significantly reduces the breakage rate; the higher average resistivity of the second edge 141 maintains high passivation quality and reduces on-state voltage loss. The magnitude of the difference between the two is not specifically limited. Simultaneously, the lower resistivity of the first edge 131 ensures a smaller change in the recombination rate before and after cutting, thereby reducing recombination at the cut edge and improving the passivation effect.

[0111] It should be noted that the average resistivity of the first edge 131 refers to the average resistivity at any two points, three points, four points, and so on; or, the average resistivity of the first edge 131 refers to the average resistivity at the aforementioned middle, center, and edge positions of the first edge 131. The method for determining the average resistivity of the second edge 141 is the same as or similar to that for the first edge 131, and will not be repeated here to avoid repetition.

[0112] In some possible embodiments, the ratio of the average resistivity in the semiconductor substrate of the second edge 141 to the average resistivity in the semiconductor substrate of the first edge 131 is between 1.2 and 350. If this ratio is too small, the reduction in the cleavage rate will not be significant enough. If this ratio is too large, the doping process will be more complex, resulting in higher process costs. Therefore, this ratio is within this range, which can not only significantly reduce the cleavage rate but also avoid increasing the process cost.

[0113] For example, the ratio of the average resistivity in the semiconductor substrate of the second edge 141 to the average resistivity in the semiconductor substrate of the first edge 131 can be 1.2, 1.4, 1.5, 1.9, 2.2, 2.5, 4, 4.5, 5, 7, 9, 10, 20, 30, 50, 60, 80, 100, 150, 180, 200, 250, 300, or 350.

[0114] In some possible embodiments, the semiconductor substrate contains antimony, whose atoms have a larger radius, which can further enhance the strength of the semiconductor substrate and reduce the fragmentation rate of the semiconductor substrate.

[0115] In some possible embodiments, the antimony doping concentration in the semiconductor substrate is 4E+13cm⁻¹. -3 Up to 2E+16cm -3This approach can balance factors such as fragmentation rate and passivation quality. For example, the antimony doping concentration in a semiconductor substrate can be as high as 4E+13cm⁻¹. -3 4.3E+13cm -3 4.5E+13cm -3 4.9E+13cm -3 5E+13cm -3 8E+13cm -3 1E+14cm -3 3E+14cm -3 4.5E+14cm -3 5E+14cm -3 7.5E+14cm -3 8E+14cm -3 9E+14cm -3 1E+15cm -3 2E+15cm -3 3.5E+15cm -3 5E+15cm -3 8E+15cm -3 9E+15cm -3 1E+16cm -3 2E+16cm -3 .

[0116] In some possible embodiments, the resistivity of the semiconductor substrate is 0.3-10 Ω·cm, which is a low-resistivity semiconductor substrate, or the resistivity of the semiconductor substrate is 10-100 Ω·cm, which is a high-resistivity semiconductor substrate. The resistivity of the semiconductor substrate is suitable, which can take into account the fragmentation rate, passivation quality, etc.

[0117] For example, the resistivity of the semiconductor substrate can be 0.3 Ω·cm, 0.5 Ω·cm, 0.8 Ω·cm, 1 Ω·cm, 1.3 Ω·cm, 1.5 Ω·cm, 2 Ω·cm, 2.5 Ω·cm, 3 Ω·cm, 3.5 Ω·cm, 4 Ω·cm, 4.5 Ω·cm, 5 Ω·cm, 5.5 Ω·cm, 6 Ω·cm, 6.5 Ω·cm, 7 Ω·cm, 7.5 Ω·cm, 8 Ω·cm, 8.5 Ω·cm, 9 Ω·cm, 9.5 Ω·cm, or 10 Ω·cm. For example, the resistivity of the semiconductor substrate can be 10 Ω·cm, 15 Ω·cm, 20 Ω·cm, 25 Ω·cm, 30 Ω·cm, 35 Ω·cm, 40 Ω·cm, 45 Ω·cm, 50 Ω·cm, 55 Ω·cm, 60 Ω·cm, 65 Ω·cm, 70 Ω·cm, 75 Ω·cm, 80 Ω·cm, 85 Ω·cm, 90 Ω·cm, 95 Ω·cm, or 100 Ω·cm.

[0118] In some possible embodiments, refer to Figure 5 The semiconductor substrate also includes two opposing short sides, at least one of the aforementioned short sides having a length of a, and at least one long side having a length of b, where 1.6 < b / a ≤ 8.

[0119] In this embodiment, b and a represent the long and short sides of the semiconductor substrate after dicing, respectively. By controlling b / a > 1.6, the entire semiconductor substrate before dicing can be a square or nearly square substrate, which improves the silicon material utilization rate during dicing. However, if b / a is too large, after dicing the entire silicon substrate into wafers, the resistivity difference between the diced edges and the non-diced edges of the wafers (e.g., wafers located on both sides) will be close. If the resistivity difference between the diced edges and the non-diced edges is too small while ensuring appropriate resistivity of the non-diced edges, the fragmentation rate of the wafers will increase. Therefore, in this embodiment, 1.6 < b / a ≤ 8 is selected.

[0120] For example, b / a can be 1.61, 1.65, 1.7, 1.9, 2, 2.3, 2.5, 2.8, 3, 3.5, 4, 4.3, 4.8, 4.5, 5, 5.1, 5.2, 6, 6.5, 7, 7.5, 8.

[0121] In some possible embodiments, the semiconductor substrate contains antimony and phosphorus, with a phosphorus to antimony mass ratio greater than 0 and less than or equal to 20. By doping the semiconductor substrate with antimony, the radius of antimony atoms is increased, further enhancing the strength of the semiconductor substrate and reducing its fragmentation rate. When antimony is doped into the semiconductor substrate, its high volatility, coupled with the different evaporation rates of antimony and phosphorus, allows for the combined effect of both dopants during substrate fabrication, improving the resistivity uniformity of the semiconductor substrate. Furthermore, the optimal phosphorus to antimony mass ratio facilitates the doping process and reduces its cost. Further, the phosphorus to antimony mass ratio in the semiconductor substrate can be from 1 to 15, improving the electrical performance of the semiconductor substrate while reducing fragmentation, and also maintaining a low doping process cost.

[0122] For example, in a semiconductor substrate, the mass ratio of phosphorus to antimony can be 0.1, 0.2, 0.5, 0.8, 1, 1.3, 1.5, 1.8, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, or 20.

[0123] It should be noted that in this application, if the semiconductor substrate contains antimony as a doping element, or if the conductor substrate contains both antimony and phosphorus as doping elements, then the semiconductor substrate is N-type doped.

[0124] It should be noted that in solar cells, when other structures contain antimony, the method for determining the doping type of that structure is the same or similar as described here. To avoid repetition, it will not be repeated here.

[0125] In some possible embodiments, refer to Figure 6 The solar cell also includes a first passivation layer 8 disposed on a side surface, such as the cut surface 13. The thickness D1 of the first passivation layer 8 is greater than the thickness of the surface passivation layer. A thicker first passivation layer 8 provides better passivation for defects on the side surface, such as the cut surface, further improving the performance of the solar cell. More specifically, the side surface, such as the cut surface, has low resistivity (e.g., high antimony doping) and a high surface state density, making it prone to leakage paths. Thickening the first passivation layer 8 enhances the field passivation effect, reduces the leakage current density on the side surface, and avoids open-circuit voltage loss due to leakage. The thickness D1 of the first passivation layer 8 is perpendicular to the first passivation layer 8, meaning the thickness direction of the first passivation layer 8 is perpendicular to the cut surface. The thickness of the surface passivation layer is parallel to the thickness direction L1 of the solar cell.

[0126] In some possible embodiments, refer to Figure 1 The first doped layer 2 and the second doped layer 3 are located on different sides of the semiconductor substrate 1 along the thickness direction L1, respectively, making this a bifacial solar cell. For example, this solar cell can be a TOPcon (passivated contact) cell, etc.

[0127] In some possible embodiments, refer to Figure 2 The first doped layer 2 and the second doped layer 3 are both located on the same side of the semiconductor substrate 1 along the thickness direction L1, specifically on the back-light side of the semiconductor substrate 1. This solar cell is a back-contact solar cell. Because its light-facing surface is not blocked by electrodes, it is more aesthetically pleasing and has better performance. The specific type of back-contact solar cell is not limited; for example, it can be a BC cell.

[0128] This application also provides a photovoltaic module, including: a cell string, which is formed by connecting multiple of the aforementioned solar cells, which may be connected by interconnecting components. Because the passivation effect of the cut surfaces in the solar cells is better, the resulting photovoltaic module has better performance. The photovoltaic module may further include: an encapsulation layer covering the surface of the cell string, which may include an encapsulating film, etc., and a cover plate covering the surface of the encapsulation layer away from the cell string. The interconnecting components here may refer to solder ribbons, conductive backsheets, etc., and are not specifically limited thereto. The cover plate may be glass, etc., and the specific material is not limited.

[0129] In some embodiments, the number of solar cells with the first edge and the second edge relatively distributed along a first direction, or the number of solar cells with the cut surface 13 and the non-cut surface 14 relatively distributed along the first direction, accounts for 20% to 100% of the total number of solar cells in the photovoltaic module. Exemplarily, the direction from the first edge to the second edge of the solar cells in this photovoltaic module can be the first direction or a direction parallel to but opposite to the first direction. The fact that the first edge and the second edge of the solar cells are relatively distributed along the first direction, or that the cut surface 13 and the non-cut surface 14 are relatively distributed along the first direction, ensures that the proportion of solar cells with the cut surface 13 and the non-cut surface 14 relatively distributed in the module can improve the overall microcrack resistance of the module.

[0130] It should be noted that a half-cell solar cell refers to one of two solar cells prepared by cutting a whole solar cell or a whole semiconductor substrate; a three-cell solar cell refers to one of three solar cells prepared by cutting a whole solar cell or a whole semiconductor substrate; and so on, an n-cell solar cell refers to one of n solar cells prepared by cutting a whole solar cell or a whole semiconductor substrate. For example, half-cell solar cells generally have the first edge and the second edge relatively distributed along a first direction, or the cut surface 13 and the non-cut surface 14 relatively distributed along the first direction. Therefore, for a photovoltaic module formed from half-cell solar cells, the number of solar cells with the first edge and the second edge relatively distributed along the first direction, or the number of solar cells with the cut surface 13 and the non-cut surface 14 relatively distributed along the first direction, accounts for 100% of the total number of solar cells in the photovoltaic module. As another example, in a three-cell solar cell prepared by cutting a whole solar cell or a whole semiconductor substrate, in one three-cell solar cell, the first edge and the second edge are not relatively distributed along the first direction, or the cut surface and the cut surface are relatively distributed; in the remaining two three-cell solar cells, the first edge and the second edge are relatively distributed along the first direction, or the cut surface and the non-cut surface are relatively distributed. Therefore, for a photovoltaic module formed by three-section solar cells, the number of solar cells that are relatively distributed along the first edge and the second edge in the first direction, or the number of solar cells that are relatively distributed along the first direction on the cut surface 13 and the non-cut surface 14, accounts for about 2 / 3 of the total number of solar cells in the photovoltaic module.

[0131] It should be noted that the photovoltaic module mentioned here can refer to any of the aforementioned solar cells, and to avoid repetition, relevant details will not be repeated. It should also be noted that the various embodiments described above can be implemented individually or in combination without logical conflict, and this application does not limit their implementation in this regard.

[0132] The following specific examples will further explain this application.

[0133] Example 1

[0134] For a batch of 1000 whole solar cells, each solar cell has a long side length of 2a and a short side length of b, where 2a > b. Each of these whole solar cells is halved to obtain a total of 2000 solar cells. The structure of the cut solar cells can be referenced from [reference needed]. Figure 1During the cutting process, the direction of the cutting line is parallel to the short side of the entire solar cell. In each solar cell obtained from the cutting: a new cutting surface is formed after cutting, and the segmented cell forms a new edge, called the first edge 131; the initial edge opposite to the first edge 131 is called the second edge 141. Taking an example where both the first and second edges correspond to the first surface, where the first surface is the light-facing surface of the semiconductor substrate, as an example. (Refer to...) Figure 3 , Figure 4 The resistivity at the center position 1311 of the first edge is R1, and the resistivity at the edge position 1312 of the first edge is R2, Δ1 = R2 - R1; the resistivity at the center position 1411 of the second edge is R3, and the resistivity at the edge position 1412 of the second edge is R4, Δ2 = R4 - R3; for each solar cell obtained from cutting, Δ1 > Δ2. Of the 2000 solar cells obtained from cutting, one is a fragment, resulting in a fragmentation rate of 1 / 2000 = 0.05%. Ten unfractured solar cells were randomly selected from the 2000 obtained solar cells, and their fill factor was measured and the arithmetic mean was calculated. The results are shown in Table 1 below. The fill factor of a solar cell refers to the ratio of the product of its current and voltage to the product of its open-circuit voltage and short-circuit current when the solar cell is at maximum power output.

[0135] Comparative Example 1

[0136] For a batch of 1000 whole solar cells, the only difference in the manufacturing process between the whole solar cells in Comparative Example 1 and the whole solar cells in Example 1 is the doping process of the semiconductor substrate. This results in all 2000 solar cells cut from Comparative Example 1 exhibiting either Δ1 < Δ2 or Δ1 = Δ2. The structure of the solar cells cut from the comparative example can be referenced... Figure 1 Of the 2000 solar cells obtained from the cutting process in Comparative Example 1, 20 were fragmented, resulting in a fragmentation rate of 20 / 2000 = 1%. Ten unfractured solar cells were randomly selected from the 2000 cells to measure their fill factor, and the arithmetic mean was calculated. The results are shown in Table 1 below.

[0137] The rest of Comparative Example 1 is the same as Example 1, and will not be repeated here to avoid repetition.

[0138] Example 2

[0139] For a batch of 1000 complete solar cells, the structure of the complete solar cell can be referred to Figure 2The remainder of Example 2 is identical to that of Example 1. Of the 2000 solar cells obtained from cutting in Example 2, the fragmentation rate is 0.1%. Ten solar cells were randomly selected from the 2000 cells to measure their fill factor, and the arithmetic mean was calculated. The results are shown in Table 1 below.

[0140] The rest of Example 2 is the same as Example 1, and will not be repeated here to avoid repetition.

[0141] Comparative Example 2

[0142] For a batch of 1000 complete solar cells, the structure of the complete solar cell can be referred to Figure 2 The only difference in the manufacturing process between the whole solar cells in the batch of Comparative Example 2 and the batch of Example 2 is the doping process of the semiconductor substrate. This results in all 2000 solar cells cut from Comparative Example 2 having either Δ1 < Δ2 or Δ1 = Δ2. Of the 2000 cut solar cells, 40 were fragmented, representing a fragmentation rate of 2%. Ten unfractured solar cells were randomly selected from the 2000 cut solar cells, and their fill factor was measured and the arithmetic mean was calculated. The results are shown in Table 1 below.

[0143] The rest of Comparative Example 2 is the same as Example 2, and will not be repeated here to avoid repetition.

[0144] It should be noted that the test methods and test environments for the same parameters in Example 1, Example 2, Comparative Example 1 and Comparative Example 2 are the same, and all comply with the relevant provisions of the national standard.

[0145] Table 1: Parameter Comparison Table for Example and Comparative Examples

[0146] Group Battery type Relative relationship of Δ1 and Δ2 Shatter (%) Fill factor Example 1 Double-sided △1＞△2 0.05 0.81 Comparative Example 1 Double-sided Δ1 < Δ2 or Δ1 = Δ2 1％ 0.79 Example 2 Back-contacted △1＞△2 0.1％ 0.82 Comparative Example 2 Back-contacted Δ1 < Δ2 or Δ1 = Δ2 2％ 0.8

[0147] From the above examples and comparative examples, it can be concluded that in this application, in the solar cell, Δ1 > Δ2, and the doping concentration changes more significantly from the center to the edge at the first edge 131, forming a more significant stress buffer structure, improving crack resistance, reducing the probability of cracking at the cut surface 13, especially at the first edge 131, and thus reducing the cracking rate. In this application, the Δ2 of the second edge 141 is lower, which can meet the requirement of a low cracking rate. Moreover, the resistivity difference between the center and edge of the second edge is smaller, resulting in a smooth transition of resistivity from the center to the edge of the second edge, reducing the potential barrier abrupt change in carrier transport, lowering the series resistance, and improving the fill factor.

[0148] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0149] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims. All of these forms are within the protection scope of this application.

Claims

1. A solar cell, characterized by, The solar cell comprises: a semiconductor substrate; a first doped layer and a second doped layer with different doping types disposed on the semiconductor substrate; a surface passivation layer located on a side of the first doped layer and the second doped layer away from the semiconductor substrate; wherein the semiconductor substrate comprises two opposite long edge edges, the two long edge edges are respectively a first edge and a second edge, and the first edge and the second edge each comprises a center position and an edge position; a resistivity of the center position of the first edge is R1, a resistivity of the edge position of the first edge is R2, a resistivity difference Δ1 = R2 - R1, a resistivity of the center position of the second edge is R3, a resistivity of the edge position of the second edge is R4, and a resistivity difference Δ2 = R4 - R3, wherein Δ1 > Δ2.

2. The solar cell according to claim 1, wherein a ratio of Δ1 to Δ2 is greater than 1 and less than or equal to 1000.

3. The solar cell according to claim 1, wherein a resistivity change rate k1 = (R2 - R1) / R1 from the edge position to the center position of the first edge, and a resistivity change rate k2 = (R4 - R3) / R3 from the edge position to the center position of the second edge, wherein k1 > k2, and / or a ratio of k1 to k2 is greater than 1 and less than or equal to 100.

4. The solar cell according to claim 1, wherein the resistivities of the first edge and the second edge satisfy R2 > R1 and R3 > R1, and / or R4 > R3 > R2 > R1.

5. The solar cell according to claim 1, wherein a region with a first preset distance range from the center position of the first edge is a first region, and a region with a second preset distance range from the center position of the first edge is a second region, wherein the first preset distance range is 0-25 mm, the second preset distance range is 60-80 mm, and a resistivity change rate per unit distance in the first region is greater than a resistivity change rate per unit distance in the second region.

6. The solar cell according to claim 1, wherein a ratio of an average doping concentration of antimony in the semiconductor substrate of the first edge to an average doping concentration of antimony in the semiconductor substrate of the second edge is 1.02 to 470.

7. The solar cell according to claim 1, wherein a resistivity of the semiconductor substrate is 0.3-10 Ω·cm or 10-100 Ω·cm.

8. The solar cell according to claim 1, wherein the semiconductor substrate contains antimony and phosphorus, and a mass ratio of phosphorus to antimony in the semiconductor substrate is greater than 0 and less than or equal to 20.

9. The solar cell according to any one of claims 1 to 8, wherein the first edge and the second edge are distributed oppositely along a first direction, and a concentration of antimony in the doped layer of the first edge is greater than a concentration of antimony in the doped layer of the second edge along the first direction. ​ ​ ​ ​ ​ The doping concentration of the antimony element in the semiconductor substrate is 4E+13 cm -3 to 2E+16 cm -3 ; and / or, ​ ​ ​ ​ ​ ​ In the first direction, the concentration of antimony in the passivation layer on the first edge is greater than the concentration of antimony in the passivation layer on the second edge.

10. The solar cell according to any one of claims 1 to 8, wherein, the semiconductor substrate comprises opposite first and second faces, and a side face connecting the first and second faces; the solar cell further comprises a passivation layer disposed on the side face; the passivation layer on the side face close to the first edge is a first passivation layer; wherein the thickness of the first passivation layer is greater than the thickness of the surface passivation layer.

11. The solar cell according to any one of claims 1 to 8, characterized in that, the semiconductor substrate further comprises two opposite short edge faces; the length of at least one of the long edge faces is b, and the length of at least one of the short edge faces is a; 1.6 < b / a ≤ 8.

12. A photovoltaic module, characterized by comprising: a cell string connected by a plurality of solar cells according to any one of claims 1 to 11; an encapsulation layer for covering the surface of the cell string; a cover plate for covering the surface of the encapsulation layer away from the cell string.

13. The photovoltaic module of claim 12, wherein, the number of solar cells with the first and second edges oppositely distributed in the first direction accounts for 20% to 100% of the total number of solar cells in the photovoltaic module.

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