Photovoltaic module and preparation method thereof

Abstract

The invention discloses a photovoltaic module and a preparation method thereof, and the photovoltaic module comprises a plurality of battery strings which are connected in series and / or in parallel, and each battery string comprises an interconnection piece and a plurality of battery pieces; the first surface of the battery piece comprises a plurality of conductive areas which are sequentially distributed along a first direction, and the conductive areas extend along a second direction; first boundaries and second boundaries which are arranged opposite to adjacent conductive regions with the same polarity are different in concave-convex morphology extending along a second direction, and regions between the adjacent conductive regions with the same polarity are arranged in a concave manner; the interconnectors extend in a first direction and pass through the conductive regions of the same polarity. According to the application, the contact stress between the adjacent conductive areas with the same polarity and the interconnection piece or the deformation stress of the interconnection piece can be dispersed, and the damage of the interconnection piece to the oppositely arranged boundary position of the adjacent conductive areas with the same polarity can be weakened; in addition, the concave-convex morphology can improve the light trapping effect.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic technology, specifically relating to a photovoltaic module and its preparation method. Background Technology

[0002] Solar cells are devices that directly convert light energy into electrical energy through the photoelectric effect. Because they use clean energy, they have broad application prospects.

[0003] However, individual solar cells have poor mechanical strength, are easily affected by the environment, and have low output voltage, current, and power. Therefore, multiple solar cells are usually packaged into photovoltaic modules. In photovoltaic modules, multiple solar cells are typically connected in series to form a cell string using interconnecting components such as solder ribbons.

[0004] However, in existing photovoltaic module cell strings, the locations where interconnects pass through are often prone to film damage, affecting the performance of the photovoltaic module, such as the passivation performance of the cells. Summary of the Invention

[0005] This application aims to provide a photovoltaic module and its manufacturing method, which at least solves one of the problems that film damage often occurs at the locations where interconnects pass through the cell string of a photovoltaic module.

[0006] A first aspect of this application provides a photovoltaic module, comprising: a plurality of battery strings connected in series and / or in parallel, the battery strings including interconnects and a plurality of battery cells; The first surface of the battery cell includes a plurality of conductive regions distributed sequentially along a first direction, the conductive regions extending along a second direction; the first boundary and the second boundary of adjacent conductive regions of the same polarity are disposed opposite to each other, the concave and convex morphologies extending along the second direction are different, and the area between the adjacent conductive regions of the same polarity is recessed. The interconnecting element passes through the conductive region of the same polarity and extends along the first direction.

[0007] During the manufacturing process of photovoltaic modules (such as automated transport), installation process (such as handling and loading), and subsequent use process (such as thermal expansion and contraction due to temperature changes in natural environments), interconnect components are particularly susceptible to movement or deformation due to external forces, or the solar cells themselves may warp. In this application, firstly, the first and second boundaries of adjacent conductive regions of the same polarity have different undulations extending along a second direction. When the interconnect component passes through these adjacent conductive regions of the same polarity, the contact situation of the interconnect component at the first and second boundaries will be significantly different. This can disperse the contact stress or deformation stress between the adjacent conductive regions of the same polarity and the interconnect component, and reduce damage to the interconnect component at the boundary locations where adjacent conductive regions of the same polarity are relatively set. Secondly, the different undulations extending along the second direction of the relatively set first and second boundaries can also improve the light-trapping effect, further enhancing the performance of the photovoltaic module.

[0008] In some embodiments, in the battery cell, the oppositely disposed first boundary and second boundary are periodically distributed along the first direction.

[0009] On the one hand, the support points of the interconnects along the first direction are more evenly distributed, so the interconnects along the first direction are more evenly stressed, and the interconnects along the first direction are flatter. This not only reduces the torsional movement of the interconnects and the resulting film damage, but also improves the electrical connection effect. On the other hand, the periodic distribution can simplify the process of forming the boundary and improve the appearance of the solar cell.

[0010] In some embodiments, at least one of the first and second boundaries exhibits a periodic distribution of undulations in its surface morphology along the second direction. On one hand, the relatively uniform distribution of support points for the multiple interconnects along the second direction helps to disperse the contact stress between the multiple interconnects and conductive regions of the same polarity, or the deformation stress of the interconnects, reducing film damage and improving electrical connection performance. On the other hand, the periodic distribution of the undulations in the boundary surface morphology simplifies the boundary formation process and also enhances the appearance of the solar cell.

[0011] In some embodiments, the first boundary or the second boundary is wavy in shape; and / or, The first boundary or the second boundary includes at least one of the following: an arc segment, a broken line segment, and a straight line segment.

[0012] In some embodiments, the first boundary or the second boundary is the outline of the adjacent conductive regions of the same polarity disposed opposite each other on the first surface, and the outline extends along the second direction.

[0013] In some embodiments, the first boundary and / or the second boundary are inclined slope structures along the thickness direction of the battery cell, and the two ends of the slope structure along the inclined direction form two contour lines extending along the second direction, the two contour lines having the same concave-convex morphology trend; or, The first boundary and / or the second boundary includes a gentle slope structure inclined along the thickness direction of the battery cell, and a protruding structure protruding from the gentle slope structure. The protruding structure is opposite to the contour line of the gentle slope structure, and the contour line is similar to the contour line of the gentle slope structure. The contour line extends along the second direction.

[0014] In this application, the first boundary is a gently sloping structure along the thickness direction of the solar cell. This results in a smooth transition without sharp corners, minimizing defects such as delamination in the film structure at this sloping boundary. This leads to high-quality film, improved passivation at the boundary, and enhanced performance of the solar cell and photovoltaic module. Furthermore, the sloping boundary better supports interconnect components, reducing breakage or damage and improving the reliability and lifespan of the photovoltaic module. Moreover, the boundary of the conductive region, sloping away from the conductive region towards the interior of the solar cell, facilitates film coverage and yields a higher-quality film, further improving passivation. Additionally, the two contour lines extending along the second direction in this sloping structure exhibit the same uneven morphology, meaning the processes at these two contour lines are largely identical, simplifying the manufacturing process.

[0015] In some embodiments, the different morphologies of the adjacent conductive regions of the same polarity extending along the second direction at their respective first and second boundaries include: The unevenness of the first boundary is different from that of the second boundary; and / or, The concavity / convexity frequency of the first boundary is different from that of the second boundary.

[0016] In some embodiments, the plurality of conductive regions include a plurality of first conductive regions and a plurality of second conductive regions alternately distributed along the first direction. The first conductive regions and the second conductive regions have different polarities, and the second conductive regions are recessed relative to the first conductive regions. Adjacent first conductive regions form the first boundary and the second boundary with the intermediate second conductive region, respectively. The intermediate second conductive region is the second conductive region between adjacent first conductive regions.

[0017] The solar cells in this photovoltaic module are back-contact cells, and their electrode structures are all located on the back side of the cell. Since there are no electrodes blocking the front side, they have high short-circuit current and conversion efficiency.

[0018] In some embodiments, the second conductive region includes a semiconductor substrate, a second doped layer disposed on the semiconductor substrate, and a transparent conductive layer, wherein the second doped layer and the transparent conductive layer extend to cover a portion of the first conductive region; The first conductive region includes the semiconductor substrate and a first doped layer, a second doped layer and a transparent conductive layer sequentially disposed on the semiconductor substrate, and at least the transparent conductive layer is provided with a disconnection opening in the overlapping region of the second doped layer and the first doped layer; The interconnecting element passes through the transparent conductive layer of the first conductive region.

[0019] In this back-contact solar cell, a leakage channel is formed where the first doped layer and the second doped layer overlap, or in other words, a built-in diode with a low reverse breakdown voltage is formed, which can play a role in preventing hot spots.

[0020] In some embodiments, in the battery cell, a recessed spacer region is provided between adjacent conductive regions, and the adjacent conductive regions are conductive regions of the same polarity. The spacer region extends along the second direction, and the adjacent conductive regions and the spacer region between the adjacent conductive regions respectively form the first boundary and the second boundary.

[0021] In some embodiments, the first side is the back side of the battery cell, the conductive region includes a semiconductor substrate and a first doped layer and a back passivation layer sequentially disposed on the semiconductor substrate, and the spacing region includes the semiconductor substrate and the back passivation layer disposed on the semiconductor substrate.

[0022] In some embodiments, the first surface is the front side of the battery cell, the conductive region includes a semiconductor substrate, a second doped layer and a front passivation layer sequentially disposed on the semiconductor substrate; the spacing region includes the semiconductor substrate and the front passivation layer disposed on the semiconductor substrate.

[0023] In some embodiments, the plurality of conductive regions include a plurality of first conductive regions and a plurality of second conductive regions alternately distributed along the first direction. The first conductive regions and the second conductive regions have different polarities. Adjacent second conductive regions are respectively first sub-conductive regions and second sub-conductive regions. The first conductive region between the first sub-conductive regions and the second sub-conductive regions is an intermediate first conductive region. A first interval region is recessed between the first sub-conductive regions and the intermediate first conductive regions. A second interval region is recessed between the second sub-conductive regions and the intermediate first conductive regions. The first boundary and the second boundary are formed between the first sub-conductive regions and the first interval region, and between the second sub-conductive regions and the second interval region.

[0024] The solar cells in this photovoltaic module are back-contact cells, and their electrode structures are all located on the back side of the cell. Since there are no electrodes blocking the front side, they have high short-circuit current and conversion efficiency.

[0025] In some embodiments, the first conductive region includes a semiconductor substrate and a first doped layer and a back passivation layer sequentially disposed on the semiconductor substrate, the second conductive region includes the semiconductor substrate and a second doped layer and a back passivation layer sequentially disposed on the semiconductor substrate, the first doped layer and the second doped layer have different doping types, and the spacing region includes the semiconductor substrate and the back passivation layer. In some embodiments, the intermediate first conductive region and the first interval region form a third boundary, and the intermediate first conductive region and the second interval region form a fourth boundary, wherein the third boundary and the fourth boundary have different convex and concave morphologies extending along the second direction; The photovoltaic module further includes an insulating element that covers the intermediate first conductive region along the first direction, as well as a portion of the third boundary and a portion of the fourth boundary; along the first direction, the insulating element and the interconnecting element electrically connected to the second conductive region at least partially overlap.

[0026] The different undulations of the third and fourth boundaries of the intermediate first conductive region extending along the second direction enhance the light-trapping effect. Furthermore, the smooth boundaries of the third and fourth boundaries of the intermediate first conductive region can reduce the recombination rate of charge carriers in the first and second conductive regions, while the rough boundaries can provide some protection against hot spots. The relatively large size of the insulating component effectively protects the intermediate first conductive region and its boundaries, ensuring that the intermediate first conductive region and the interconnects electrically connected to the aforementioned second conductive region will not come into contact, and that the interconnects electrically connected to the aforementioned second conductive region will not damage the intermediate first conductive region. Along the first direction, the insulating component and the interconnects electrically connected to the aforementioned second conductive region at least partially overlap. The large size of the insulating component also effectively prevents short circuits at the location of the intermediate first conductive region.

[0027] In some embodiments, the third boundary and / or the fourth boundary of the battery cell are periodically distributed along the first direction.

[0028] On the one hand, the support points of the interconnects that contact the second conductive area along the first direction are more evenly distributed. Therefore, the interconnects that contact the second conductive area along the first direction are subjected to more even force, and the interconnects are flatter along the first direction. This not only reduces the torsional movement of the interconnects and the resulting film damage, but also improves the electrical connection effect. On the other hand, the periodic distribution can simplify the process of forming the boundary and can beautify the appearance of the solar cell.

[0029] In some embodiments, the first boundary and the third boundary have different convex and concave morphologies extending along the second direction.

[0030] In some embodiments, the second boundary and the fourth boundary have different convex and concave morphologies extending along the second direction.

[0031] In some embodiments, the intermediate first conductive region is recessed relative to the first sub-conductive region, and the first interval region is recessed relative to the intermediate first conductive region, wherein the recess depth of the first interval region relative to the first sub-conductive region is less than or equal to 3000 nm.

[0032] The smaller undulations on the backlight side of the semiconductor substrate reduce defects such as film breaks, and allow for a suitable increase in film thickness, thus improving passivation of the solar cell. Furthermore, when a small leakage current is transmitted through adjacent first and second conductive regions, the shallower recess of the gap region relative to the second conductive region results in a shorter leakage current transmission distance and better hotspot prevention.

[0033] In some embodiments, the recess depth of the first spacing region relative to the first sub-conductive region is 500 nm to 3000 nm.

[0034] If the recess depth is too small, it may introduce short-circuit risk. Therefore, the recess depth in this application takes into account both low short-circuit risk and good passivation effect.

[0035] In some embodiments, the first boundary and the third boundary form a plurality of facing, closely protruding structures along the first direction; and / or, The second boundary and the fourth boundary form several convex structures facing each other and close to each other along the first direction.

[0036] At the location of the convex structure, the distance between the first conductive area and the adjacent second conductive area is small, or the straight-line distance is small. When the temperature rises and a hot spot effect occurs after the cell is shaded, the adjacent first and second conductive areas will preferentially form a soft breakdown area from the location of the convex structure with a small straight-line distance, which will disperse the heat, reduce the hot spot temperature, and avoid the risk of fire. Moreover, during the period when the hot spot effect does not occur, the convex structure does not affect the normal use of the cell.

[0037] In some embodiments, the battery cell further includes a connecting portion, which is continuously or intermittently disposed on the conductive region and is used to electrically connect the conductive region to the interconnect.

[0038] A second aspect of this application provides a method for manufacturing a photovoltaic module, applicable to any of the aforementioned photovoltaic modules, comprising: A plurality of battery cells are provided, wherein a first surface of the battery cells includes a plurality of conductive regions distributed sequentially along a first direction, the conductive regions extending along a second direction, and the concave and convex morphologies of the first and second boundaries of adjacent conductive regions of the same polarity extending along the second direction are different. An interconnect is disposed on the battery cell; the interconnect passes through the adjacent conductive regions of the same polarity and extends along the first direction.

[0039] In some embodiments, providing a plurality of battery cells includes: A second doped layer is formed on the back side of the semiconductor substrate of at least one of the plurality of solar cells; A first laser is used to form a second doped layer within a first sub-conductive region and a second sub-conductive region. The first laser acts on the middle first conductive region and on the positions corresponding to the first and second interval regions located on both sides of the middle first conductive region in the first direction. The two contour lines of the first laser spot extending along the second direction have different concave and convex shapes. A first doped layer is formed at the corresponding positions of the intermediate first conductive region, the first interval region, and the second interval region, as well as on the second doped layer within the first sub-conductive region and the second sub-conductive region. The first doped layer and the second doped layer have different conductivity types. The first doped layer in the middle first conductive region is formed by using a second laser. The second laser acts on the positions corresponding to the first sub-conductive region, the second sub-conductive region, the first interval region, and the second interval region. The two contour lines of the second laser spot extending along the second direction have different concave and convex shapes. A back passivation layer is formed on the outermost layer of the battery cell.

[0040] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0041] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a partial schematic diagram of a cell string in a photovoltaic module according to an embodiment of this application; Figure 2 and Figure 11 This is a partial schematic diagram of the back side of a solar cell in a photovoltaic module according to an embodiment of this application; Figures 3 to 5 These are schematic diagrams of several structures of solar cells in a photovoltaic module according to embodiments of this application; Figure 6 and Figure 10 This is a partial structural schematic diagram showing the location of the boundary of the solar cell in a photovoltaic module according to an embodiment of this application; Figure 7 This is a partial top view of the location of the boundary of the solar cell in the photovoltaic module according to an embodiment of this application; Figure 8 This is a partial schematic diagram of a boundary of a solar cell in a photovoltaic module according to an embodiment of this application; Figure 9 This is a partial SEM image of the back side of a solar cell in a photovoltaic module according to an embodiment of this application; Figure 12 This is a partial front view of a solar cell in a photovoltaic module according to an embodiment of this application.

[0042] Figure label: 100 - First conductive region, 200 - Second conductive region, 201 - First sub-conductive region, 202 - Second sub-conductive region, 300 - Spacing region, 301 - First spacing region, 302 - Second spacing region, 1 Semiconductor substrate, 2 Tunneling through oxide layer, 3 N-type doped polycrystalline silicon layer, 4 First boundary, 41 - First contour line, 42 - Second contour line, 5 Second boundary, 51-Third contour line, 52-Fourth contour line, 43-Protruding structure, 44-Fifth contour line, 45-Sixth contour line, 6 Intrinsic amorphous silicon layer, 7 P-type doped amorphous silicon layer, 8 Front passivation layer, 9 Front anti-reflection layer, 10 P-type doped polysilicon layer, 11 Transparent conductive layer, 12 Back passivation layer, 13 14 - Insulator, 15 - Protruding structure, 16 - Third boundary, 17 - Fourth boundary, 18 - Fifth boundary, 19 - Sixth boundary, 2 - Interconnector. Detailed Implementation

[0043] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0044] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0045] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0046] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0047] This application provides a photovoltaic module comprising: a plurality of cell strings connected in series and / or in parallel. The number of cell strings in the photovoltaic module is not limited. Each cell string includes an interconnecting element 2 (see reference 2). Figure 1 (and several solar cells. The solar cells contain PN junctions, which can generate and transport charge carriers. See reference...) Figures 3 to 5A solar cell typically includes a semiconductor substrate 1 and doped layers. The semiconductor substrate 1 can be a silicon substrate, for example, N-type or P-type monocrystalline silicon, providing long-lived charge carriers. The doped layers can include P-type and N-type doped layers. 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). The materials of the N-type and P-type doped layers 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, monocrystalline, or polycrystalline. The materials of the N-type and P-type doped layers can be the same or different. For example, both the N-type and P-type doped layers can be doped polycrystalline silicon. Another example: the P-type doped layer can be doped polycrystalline silicon, and the N-type doped layer can be at least one of doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon. P-type doped layers can be obtained by in-situ doping on the surface of a silicon substrate or by deposition on the surface of a silicon substrate. Similarly, N-type doped layers can be obtained by in-situ doping on the surface of a silicon substrate or by deposition on the surface of a silicon substrate. For example, a P-type doped layer can be formed on a silicon substrate by in-situ doping. As another example, a P-type doped layer can be deposited on the surface of a silicon substrate (e.g., it can be an epitaxial doped layer).

[0048] The solar cell includes a first surface along its thickness direction Z, which can be the back surface of the solar cell (see reference). Figure 4 and Figure 5 ), and / or the front of the battery cell (see reference) Figure 12 During normal operation of the solar cell, the front surface of the cell primarily receives sunlight, while the back surface is opposite to the front surface.

[0049] Reference Figure 1 and Figures 9 to 12The first surface of the solar cell includes a plurality of conductive regions sequentially distributed along a first direction X. These conductive regions in this application can be considered to include functional layers or other film structures at corresponding positions in the solar cell. The conductive regions extend along a second direction Y. The first boundary 4 and second boundary 5, which are adjacent conductive regions of the same polarity and arranged close to or opposite to each other, have different morphologies extending along the second direction Y. The aforementioned first boundary 4 and second boundary 5, which are close to or opposite to each other, are respectively located within adjacent conductive regions of the same polarity. The interconnecting member 2 extends along the first direction X and passes through the aforementioned conductive regions of the same polarity. These conductive regions of the same polarity can be electrically connected to the interconnecting member 2 via a conductive structure. This conductive structure may include a current collector 13, etc. Specifically, interconnect 2 traverses the conductive area along the first direction X. During photovoltaic module manufacturing (e.g., automated transport), installation (e.g., handling and loading), and subsequent use (e.g., under natural conditions where temperature changes cause thermal expansion and contraction), interconnect 2 is particularly susceptible to movement or deformation due to external forces, or the solar cells themselves may warp. This can damage the contacting conductive area, especially the boundary of the conductive area, affecting the quality of the film layer at the boundary, particularly the passivation performance. Furthermore, interconnect 2 typically connects conductive areas of the same polarity, and the areas between conductive areas of the same polarity are usually recessed. Therefore, interconnect 2 often damages the relative boundary positions of conductive areas of the same polarity.

[0050] In this application, firstly, the first boundary 4 and the second boundary 5, which are adjacent conductive regions of the same polarity and are arranged close to or opposite to each other, have different undulations extending along the second direction Y. This results in differences in the contact conditions of the interconnect 2 at the aforementioned first boundary 4 and second boundary 5, which can disperse the contact stress between the adjacent conductive regions of the same polarity and the interconnect 2, or the deformation stress of the interconnect 2, and can reduce damage to the interconnect at the boundary positions where adjacent conductive regions of the same polarity are close to or opposite to each other. Secondly, the different undulations extending along the second direction of the oppositely arranged first and second boundaries can also improve the light-trapping effect, further enhancing the performance of the photovoltaic module.

[0051] It should be noted that adjacent conductive regions of the same polarity here can refer to two adjacent N-polarity conductive regions and / or two adjacent P-polarity conductive regions. The interconnecting element can be a solder strip, etc. The first boundary 4 and the second boundary 5 of adjacent conductive regions of the same polarity being positioned opposite each other refer to: the boundary of one conductive region closest to the other, and the boundary of the other conductive region closest to the first conductive region. For example, Figure 1In the above, the first boundary 4 and the second boundary 5, which are set opposite to adjacent conductive regions of the same polarity, can refer to the lower boundary of the first P-type doped layer, such as P-type doped layer 10, and the upper boundary of the second P-type doped layer, such as P-type doped layer 10, in order from top to bottom.

[0052] It should be noted that, referring to Figures 3 to 5 Inside a solar cell, the conductive regions can be divided based on whether a doped layer covers the semiconductor substrate (or, if a tunneling oxide layer is present beneath the doped layer, the region covered by the tunneling oxide layer). For example, regarding... Figure 3 The solar cell shown has a conductive region 100 on the back side of the semiconductor substrate, covered by a first doped layer (such as an N-type doped polysilicon layer 3). For example, regarding... Figure 4 In the battery cell shown, the area covered by the first doped layer 3 is the first conductive region 100. For example, regarding... Figure 5 The area covered by the first doped layer (such as the N-type doped polycrystalline silicon layer 3) of the battery cell shown is the first conductive region 100.

[0053] In some possible embodiments, refer to Figure 1 and Figure 2 In this application, the uneven morphology extending along the second direction Y refers to the convex or concave morphology of the boundary extending along the second direction Y in the first direction X. The first boundary can be the outline of a conductive region on the first surface of the solar cell, and the second boundary can be the outline of another conductive region on the first surface. The first surface can be the back surface of the solar cell, and the first surface of both conductive regions refers to the outermost film layer of each conductive region. However, the first surfaces of the two conductive regions can be flush or have a height difference; this application does not limit this. For example, refer to... Figure 6 , Figure 7 The first boundary 4 is the first contour line 41 in the figure, and the second boundary 5 is the second contour line 51 shown in the figure. Or refer to Figure 10 The first outline in the middle is 44.

[0054] In some possible embodiments, refer to Figure 6 and Figure 7 At least one of the first and second boundaries has a gently sloping structure along the thickness direction Z of the battery cell. Both the first boundary 4 and the second boundary 5 include a region between two contour lines extending along the second direction Y. That is, the first boundary 4 includes a sidewall between a first contour line 41 and a second contour line 42 extending along the second direction Y, wherein the second contour line 42 is closer to the battery interior than the first contour line 41. The second boundary 5 includes a sidewall between a third contour line 51 and a fourth contour line 52 extending along the second direction Y, wherein the fourth contour line 52 is closer to the battery interior than the third contour line 51. Figure 6 and Figure 7 In the first boundary 4, the first contour line 41 and the second contour line 42 extending along the second direction Y have the same concave-convex morphology, and the third contour line 51 and the fourth contour line 52 of the second boundary 5 extending along the second direction Y have the same concave-convex morphology trend. For example, the conductive region here can be an N-type conductive region. In this way, the concave-convex morphology of the sidewall corresponding to the first boundary and the sidewall corresponding to the second boundary are different, which can better disperse the stress of the interconnect 2 on the two conductive regions. In this application, towards the interior of the battery cell ( Figure 6 (In the opposite direction of Z in the middle), if the boundary of this conductive region, such as the first boundary 4, slopes away from the conductive region, then the boundary transitions smoothly without forming sharp corners. The film structure at this sloped boundary is unlikely to exhibit defects such as discontinuity, resulting in good film quality. This improves the passivation effect at the boundary, enhancing the performance of the solar cells and photovoltaic modules. Furthermore, the sloped boundary provides better support for interconnect components, reducing breakage or damage, and improving the reliability and lifespan of the photovoltaic modules. (Towards the interior of the solar cell) Figure 6 (The opposite direction of Z in the middle), the boundary of the conductive region, such as the first boundary 4, is inclined in a direction away from the conductive region, which also facilitates the coverage of the film layer, is more conducive to obtaining a film layer of better quality, and further improves the passivation effect.

[0055] In yet another possible embodiment, reference is made to Figure 10 The first boundary includes a gently sloping structure inclined along the thickness direction Z of the battery cell, and a protruding structure 43 protruding from the gently sloping structure. This protruding structure 43 can be a brim structure, etc. For example, the conductive region here can be a P-type conductive region. The protruding structure 43 contains a contour line deviating from the gently sloping structure, i.e., a fifth contour line 44, and the gently sloping structure contains a contour line deviating from the protruding structure along the second direction Y, i.e., a sixth contour line 45. The fifth contour line 44 and the sixth contour line 45 have the same concave-convex trend. For example, the first boundary 4 of this application can be the sidewall between the fifth contour line 44 and the sixth contour line 45 and the second boundary (and...). Figure 10 The sidewalls of the interconnect 2 (which are the same as the first boundary in the diagram, but not shown) are different. In this scenario, due to the presence of the protruding structure 43, the stress of the interconnect 2 on the protruding structure 43 is more significant. Therefore, by differentiating the concave-convex contour line 44 of the protruding structure from the concave-convex contour line of the second boundary protruding structure, it is more important to disperse the stress of the interconnect 2 and reduce its impact on the boundary of the conductive area.

[0056] It should be noted that the concave-convex shape of at least a portion of the second contour line 42 extending along the second direction Y may be different from the concave-convex shape of at least a portion of the fourth contour line 52 extending along the second direction Y; or the concave-convex shape of at least a local surface region between the first contour line 41 and the second contour line 42 extending along the second direction Y may be different from the concave-convex shape of at least a local surface region between the third contour line 51 and the fourth contour line 52 extending along the second direction Y.

[0057] It should be noted that, in this application, when the boundary of the conductive region is a sloping slope structure or includes a sloping slope, in the first direction X, the boundary of the conductive region can be the outline of the outermost surface of the sloping slope.

[0058] It should be noted that at least one of the third, fourth, fifth, and sixth boundaries can also be a gently sloping structure, which has the same or similar beneficial effects as at least one of the first and second boundaries being a gently sloping structure. To avoid repetition, this will not be elaborated here.

[0059] It should be noted that the term "same" as used in this application includes identical or identical items with certain deviations. All content described above in the specific embodiments of this application applies to the bifacial solar cells mentioned later (as shown in reference...). Figure 3 ),as well as Figure 4 and Figure 5 All of the back contact battery cells mentioned are applicable.

[0060] In some possible embodiments, the electrode structure includes a connection portion continuously or intermittently disposed on a portion of the conductive region and used to electrically connect the conductive region to the interconnect 2, thereby achieving a better current collection effect. The connection portion can be continuously disposed (e.g., a main grid) or intermittently disposed (e.g., electrode pads in a cell without a main grid or with few main grids).

[0061] In some embodiments, refer to Figure 1 , Figure 2 , Figure 8 and Figure 9 The different concavity and convexity morphologies of the first boundary 4 and the second boundary 5 mentioned in this application, extending along the second direction Y, may include: different concavity and convexity amplitudes of the first boundary 4 and the second boundary 5, and / or different concavity and convexity frequencies of the first boundary 4 and the second boundary 5. Here, the concavity and convexity amplitude refers to: [referring to...] Figure 8The boundary includes peaks and troughs in the first direction X. The distance R between a peak and a trough of the boundary in the first direction X can be the average of the distances R between multiple peaks and multiple troughs of the boundary in the first direction X. The concavity / convexity frequency mentioned in this application refers to the number of concave points (troughs) and / or convex points (peaks) in the concavity / convexity morphology of the boundary within the same dimension along the second direction Y, or the number of times concave points and / or convex points are counted in the concavity / convexity morphology of the boundary within a unit dimension along the second direction Y. The higher the count, the greater the concavity / convexity frequency. Alternatively, the concavity / convexity frequency mentioned in this application refers to the distance d between adjacent peaks or troughs along the second direction Y. The smaller d is, the greater the concavity / convexity frequency.

[0062] Here, the first direction X differs from the aforementioned second direction Y, and the angle between them is not limited. For example, the angle between the first direction X and the second direction Y can be 90°. In this application, uneven topography or different uneven topography can improve the light-trapping effect, further enhancing the performance of photovoltaic modules.

[0063] The term "conductive region extending along a second direction" as mentioned in this application refers to the overall orientation of the conductive region along the second direction, but local bending in other directions is permitted. The definition of other structures extending along a certain direction is similar.

[0064] In some embodiments, refer to Figure 1 , Figure 2 and Figure 9 In the solar cell, along the first direction X, the aforementioned opposing first boundaries 4 and second boundaries 5 are periodically distributed. On the one hand, the support points of the interconnects 2 that contact the conductive area along the first direction X are periodically similarly distributed. Therefore, the entire interconnect 2 on the same surface is flatter along the first direction X, which not only reduces the torsional movement of the interconnect 2 and the resulting film damage, but also improves the electrical connection effect. On the other hand, the periodic distribution simplifies the boundary formation process and improves the appearance of the solar cell. It should be noted that, as mentioned in this application, the periodic distribution of the aforementioned opposing first boundaries 4 and second boundaries 5 along the first direction X means that the pair of opposing first boundaries 4 and second boundaries 5 are repeatedly and uniformly distributed along the first direction X. For example, Figure 2 and Figure 9 In this context, the first sub-conductive region 201 includes a first boundary 4 and a fifth boundary 18 extending along the second direction Y, and the second sub-conductive region 202 includes a second boundary 5 and a sixth boundary 19 extending along the second direction Y. The periodic distribution here can be such that the fifth boundary 18 and the second boundary 5, which are separated by two intervals, have the same convex and concave morphology extending along the second direction Y, and the first boundary 4 and the sixth boundary 19 have the same convex and concave morphology extending along the second direction Y. For example... Figure 11In the first conductive region 100, the uneven shape of the first boundary 4 extending along the second direction from top to bottom is approximately the same as the uneven shape of the first boundary 4 extending along the second direction from top to bottom of the second conductive region 100. For example, Figure 11 In the first conductive region 100, the uneven morphology of the second boundary 5 extending along the second direction from top to bottom is approximately the same as the uneven morphology of the second boundary 5 extending along the second direction from top to bottom of the second conductive region 100. Alternatively, for a solar cell, the uneven morphology of the boundary on the same side of the conductive regions of the same polarity extending along the second direction Y is the same.

[0065] In some embodiments, refer to Figure 1 , Figure 2 , Figure 9 , Figure 11 and Figure 12 In the solar cell, at least one of the first boundary 4 and the second boundary 5 has a periodically distributed undulation of its concave-convex morphology along the second direction Y. On the one hand, multiple interconnects 2 are provided along the second direction Y, and the support points of each interconnect 2 are similar, making the support points of the multiple interconnects more uniform. This helps to disperse the contact stress or deformation stress between the multiple interconnects 2 and the conductive area of ​​the same polarity, reduce film damage at multiple locations, and improve the electrical connection effect. On the other hand, the periodic distribution of the undulation of the boundary can simplify the boundary formation process and also improve the appearance of the solar cell.

[0066] It should be noted that the periodic distribution of the undulations of the boundary's topography along the second direction Y can refer to at least one of the first, second, third, fourth, fifth, and sixth boundaries, all of which fall within the scope of protection of this application. The undulations of the boundary's topography along the second direction Y refer to the protrusions or depressions of the boundary along the first direction X, as well as the amplitude of these protrusions and depressions. The periodic distribution of the boundary's topography mentioned in this application means that the protrusions and their amplitudes along the first direction X are repeated and uniformly distributed, and the depressions and their amplitudes along the first direction X are also repeated and uniformly distributed.

[0067] For example, Figure 1 , Figure 2 , Figure 9 , Figure 11 and Figure 12 In the middle, the undulation of the concave-convex shape of the first boundary 4, the second boundary 5, the third boundary 16, the fourth boundary 17, the fifth boundary 18, and the sixth boundary 19 along the second direction Y all exhibit a periodic distribution.

[0068] In some embodiments, refer to Figure 1 , Figure 2 and Figure 9 , Figure 11 and Figure 12 The first or second boundary is wavy in shape; and / or the first or second boundary includes at least one of the following: an arc segment, a broken line segment, and a straight line segment. The diverse shapes of the boundaries can enhance the light-trapping effect. SEM refers to scanning electron microscopy.

[0069] In some embodiments, refer to Figure 6 , Figure 11 and Figure 12 In the solar cell, a recessed spacer region 300 is provided between adjacent conductive regions, and the adjacent conductive regions are conductive regions of the same polarity. Figure 6 and Figure 12 All of them are P-type conductive regions. Figure 11 The aforementioned interval region 300 extends along the second direction Y, and adjacent conductive regions, together with the intermediate interval region 300, form the aforementioned first boundary 4 and second boundary 5, which are arranged close to or opposite to each other. The fact that adjacent conductive regions are of the same polarity indicates that the first surface of the battery cell consists entirely of conductive regions of the same polarity, and that the battery cell is a double-sided battery cell with electrode structures on both sides.

[0070] Figure 3 This is a schematic diagram of the structure of a bifacial solar cell according to this application. In some embodiments, refer to... Figure 3 as well as Figure 11 The back surface of the battery cell includes a plurality of first conductive regions 100 sequentially distributed along a first direction X, with a recessed spacer region 300 between adjacent first conductive regions; each first conductive region 100 includes a semiconductor substrate 1 and a first doped layer and a back passivation layer 12 sequentially disposed on the semiconductor substrate 1, the first doped layer being close to the semiconductor substrate 1; the spacer region on the back surface includes a semiconductor substrate and a back passivation layer disposed on the semiconductor substrate; and / or, referring to Figure 12 The front side of the solar cell includes a plurality of second conductive regions 200 sequentially distributed along a first direction, with a recessed spacer region 300 between adjacent second conductive regions 200. The first and second conductive regions have different polarities; one is an N-type conductive region and the other a P-type conductive region. For example, the first conductive region is an N-type conductive region, and the second conductive region is a P-type conductive region. Each second conductive region includes a semiconductor substrate 1, a second doped layer sequentially disposed on the semiconductor substrate, and a front passivation layer 8, with the second doped layer close to the semiconductor substrate 1. The front spacer region includes the semiconductor substrate and the front passivation layer disposed on the semiconductor substrate. The first and second doped layers have different doping types; one is a P-type doped layer and the other is an N-type doped layer.

[0071] For example, refer to Figure 3 and Figure 11The first conductive region on the back side of the solar cell may include: a semiconductor substrate 1, a tunneling oxide layer 2, an N-type doped polysilicon layer 3, and a back passivation layer 12 sequentially stacked on the back side of the semiconductor substrate 1, and a spacer region on the back side including the semiconductor substrate and the back passivation layer, wherein the back passivation layer covers the semiconductor substrate in the spacer region on the back side. (Refer to...) Figure 3 and Figure 12 The second conductive region on the front side of the solar cell includes a semiconductor substrate 1 and doped layers, such as a P-type doped layer 7 and a front passivation layer 8, stacked sequentially on the front side of the semiconductor substrate 1. The front spacing region includes the semiconductor substrate and the front passivation layer, with the front passivation layer covering the semiconductor substrate in this spacing region. The materials for the front and back passivation layers can be selected from alumina, silicon nitride, etc. Electrode structures are disposed on both sides of the semiconductor substrate. The electrode structure on the light-facing side of the semiconductor substrate is electrically connected to the P-type doped amorphous silicon layer 7 in the second conductive region. The electrode structure on the back-facing side of the semiconductor substrate is electrically connected to the N-type doped polycrystalline silicon layer 3 in the first conductive region. The electrode structure on the side of the back passivation layer 12 facing away from the semiconductor substrate 1 is used to collect and transport charge carriers in the first doped layer, and the electrode structure on the side of the front passivation layer 8 facing away from the semiconductor substrate 1 is used to collect and transport charge carriers in the second doped layer.

[0072] It should be noted that the materials used in the electrode structure mentioned in this application are not limited. The electrode structure can be at least one of the following: current collector electrode, main grid, electrode disk (PAD), etc. In the accompanying drawings of this application, the dashed lines L2 to L6 are only for illustrating different areas; in actual solar cells, there are no such clear boundaries between different areas.

[0073] In some embodiments, refer to Figure 3 For bifacial solar cells, the first side of the solar cell is the front and / or back side of the solar cell.

[0074] For example, Figure 12 In this configuration, the front side of the solar cell consists entirely of P-type conductive regions. A recessed spacer region 300 is provided between adjacent P-type conductive regions, extending along the second direction Y. Each adjacent P-type conductive region, together with the spacer region 300, forms the aforementioned first boundary 4 and second boundary 5, which are positioned close to or opposite to each other. The first boundary 4 and second boundary 5 have different undulations extending along the second direction Y. And / or, refer to... Figure 11The back of the battery cell is an N-type conductive region. A recessed spacer region 300 is provided between adjacent N-type conductive regions. The adjacent N-type conductive regions are conductive regions of the same polarity. The spacer region 300 extends along the second direction Y. The adjacent N-type conductive regions and the spacer region 300 between the adjacent N-type conductive regions respectively form the aforementioned first boundary 4 and second boundary 5 that are close to or opposite to each other.

[0075] In some embodiments, refer to Figure 4 The aforementioned conductive regions include several first conductive regions 100 and several second conductive regions 200 alternately distributed along the first direction X. The first conductive regions 100 and the second conductive regions 200 have different polarities; one is an N-type conductive region, and the other is a P-type conductive region. The second conductive regions 200 are recessed relative to the first conductive regions 100. The second conductive regions 100 between adjacent first conductive regions 200 form intermediate second conductive regions. Adjacent first conductive regions 200 and the intermediate second conductive regions respectively form the aforementioned first boundary 4 and second boundary 5, which are close to or opposite to each other. The solar cells in this photovoltaic module are back-contact solar cells, and their electrode structures are all located on the back side of the cell. Because there are no electrode structures obstructing the front side, they have higher short-circuit current and conversion efficiency.

[0076] It should be noted that, Figure 4 It can be considered that it is only a part of the battery cell in the first direction X. Figure 4 This only shows one first conductive region 100 and one second conductive region 200. In an actual solar cell, there are at least two second conductive regions 200 and one first conductive region 100. The aforementioned alternating distribution of several first conductive regions 100 and several second conductive regions 200 along the first direction X specifically means that along the first direction X, one first conductive region 100 is followed by one second conductive region 200, and then another first conductive region 100. Figure 4 It can be assumed that there is at least one second conductive region 200 to the right of the first conductive region 100. Figure 4 The boundary of the first boundary or the second boundary formed by the second conductive region 200 and the adjacent first conductive region 100, which are close to or opposite to each other, is located at the junction of the second conductive region 200 and the first conductive region 100 and extends along the gentle slope structure of the second conductive region 200 at the junction to the first surface of the battery cell.

[0077] In some embodiments, refer to Figure 4The first conductive region 100 of the solar cell may include: a semiconductor substrate 1, a first doped layer (such as an N-type doped polycrystalline silicon layer 3) disposed on the semiconductor substrate 1, and a transparent conductive layer 11. The second conductive region 200 may include a semiconductor substrate 1, a second doped layer (such as a P-type doped amorphous silicon layer 7) disposed on the semiconductor substrate 1, and a transparent conductive layer 11, wherein the second doped layer and the transparent conductive layer 11 extend to cover a portion of the first conductive region. The first doped layer and the second doped layer have opposite conductivity types, one being a P-type doped layer and the other an N-type doped layer. The first doped layer is disposed in the first conductive region 100. The second doped layer is disposed in the second conductive region 200 and extends to cover a portion of the first doped layer. The second doped layer and the transparent conductive layer 11 are disposed on the side of the first doped layer and the second doped layer away from the semiconductor substrate 1, and at least at a portion of the overlap between the second doped layer and the first doped layer, at least the transparent conductive layer is disconnected or forms an opening. The disconnection mentioned in this application refers to physical insulation to avoid short circuits. Interconnectors pass through the transparent conductive layer of the aforementioned first conductive region.

[0078] In some embodiments, Figure 4 The solar cell may also include a tunneling oxide layer 2 stacked with the first doped layer and located in the first conductive region 100, wherein the tunneling oxide layer 2 is closer to the semiconductor substrate 1. Figure 4 The solar cell may also include an intrinsic amorphous silicon layer 6 stacked with a second doped layer, the intrinsic amorphous silicon layer 6 being closer to the semiconductor substrate 1. Figure 4 The solar cell may also include a front passivation layer 8 and a front antireflection layer 9 sequentially stacked on the light-facing side of the semiconductor substrate 1 to provide a good passivation and antireflection effect on the light-facing side of the semiconductor substrate 1. The specific material of the transparent conductive layer 11 mentioned in the application can be selected from ITO (indium tin oxide), fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), etc., and there is no limitation on its specific material. Figure 4 The battery cell may also include an electrode structure located on the side of the transparent conductive layer 11 away from the semiconductor substrate 1. The electrode structure includes an electrode structure located in the first conductive region 100 for collecting and transporting charge carriers within the first conductive region 100, and an electrode structure located in the second conductive region 200 for collecting and transporting charge carriers within the second conductive region 200.

[0079] In some embodiments, refer to 1, Figure 2 , Figure 5 and Figure 9The aforementioned conductive regions include several first conductive regions 100 and several second conductive regions 200 that are alternately distributed along the first direction X. The first conductive regions 100 and the second conductive regions 200 have different polarities, one of which is an N-type conductive region and the other is a P-type conductive region. A recessed interval region 300 is provided between adjacent first conductive regions 100 and second conductive regions 200. The second conductive region 200 can specifically be a first sub-conductive region 201 and a second sub-conductive region 202. The first conductive region 100 between the first sub-conductive region 201 and the second sub-conductive region 202 is an intermediate first conductive region. A first interval region 301 is recessed between the first sub-conductive region 201 and the intermediate first conductive region. A second interval region 302 is recessed between the second sub-conductive region 202 and the intermediate first conductive region. Alternatively, two interval regions 300 are provided between the first sub-conductive region 201 and the second sub-conductive region 202. The interval region closer to the first sub-conductive region 201 is the first interval region 301, and the interval region closer to the second sub-conductive region 202 is the second interval region 302. The first boundary 4 and the second boundary 5, which are arranged close to or opposite to each other, are formed between the first sub-conductive region 201 and the first interval region 301, and between the second sub-conductive region 202 and the second interval region 302. The solar cells in this photovoltaic module are back-contact cells, with their electrode structures all located on the back side of the cell. Since there are no electrode structures blocking the front side, they have higher short-circuit current and conversion efficiency.

[0080] It should be noted that, Figure 5 It can be considered as Figure 2 The diagram shows a partial schematic of adjacent first conductive regions 100 and second conductive regions 200 in a solar cell. In an actual solar cell, there are at least two second conductive regions 200 and one first conductive region 100. The aforementioned alternating distribution of several first conductive regions 100 and several second conductive regions 200 along the first direction X specifically refers to a distribution along the first direction X where one first conductive region 100 is followed by one second conductive region 200, and then another first conductive region 100.

[0081] In some embodiments, refer to Figure 1 , Figure 2 and Figure 9The first conductive region 100 between the first sub-conductive region 201 and the second sub-conductive region 202 is an intermediate first conductive region. This intermediate first conductive region forms a third boundary 16 with the aforementioned first interval region 301 and a fourth boundary 17 with the aforementioned second interval region 302. The third and fourth boundaries of the first conductive region 100 have different undulating shapes extending along the second direction Y, which can improve the light-trapping effect. The photovoltaic module also includes an insulating member 14, which covers the intermediate first conductive region along the first direction X, as well as a portion of the third boundary 16 and a portion of the fourth boundary 17 of the intermediate first conductive region. The insulating member 14 is relatively large, which can fully protect the first conductive region 100 and its boundaries, ensuring that the first conductive region and the interconnecting member 2 electrically connected to the aforementioned second conductive region 200 will not come into contact, and the interconnecting member 2 electrically connected to the aforementioned second conductive region 200 will not damage the first conductive region. Along the first direction X, the insulating member 14 and the interconnecting member 2 electrically connected to the aforementioned second conductive region 200 at least partially overlap. The larger size of the insulating member 14 can also sufficiently prevent short circuits at the location of the first conductive region 100. Furthermore, the third boundary 16 and the fourth boundary 17 have different undulations extending along the second direction Y, which, relative to flat boundaries, can help enhance the stability or pull-out force of the fixation between the insulating member 14 and the intermediate first conductive region.

[0082] It should be noted that, for Figure 1 , Figure 2 and Figure 9 The first and second boundaries of the second conductive region 200, and the third boundary 16 and fourth boundary 17 of the first conductive region 100, all extend along the second direction Y and are located at the edges of the first conductive region 100 and the second conductive region 200. The insulating component 14 only needs to have good insulation properties; its specific material is not limited, for example, it can be thermosetting insulating adhesive or photocuring insulating adhesive.

[0083] When the first boundary 4 and the third boundary 16 are sidewalls, the light-trapping effect of the gap between the first boundary 4 and the third boundary 16 can be improved.

[0084] In some embodiments, refer to Figure 1 , Figure 2 and Figure 9In the solar cell, the first boundary 4 and the third boundary 16 have different undulations extending along the second direction Y. Therefore, they may be relatively close to each other at certain positions. When the temperature rises and a hot spot effect occurs after the solar cell is blocked, the adjacent first conductive region 100 and second conductive region 200 will preferentially form a soft breakdown region from the relatively close position to disperse the heat, reduce the hot spot temperature, and avoid the risk of fire. Moreover, during the period when the hot spot effect does not occur, the relatively close position does not affect the normal use of the solar cell.

[0085] In some embodiments, refer to Figure 1 , Figure 2 and Figure 9 In the solar cell, the second boundary 5 and the fourth boundary 17 have different undulations extending along the second direction Y. Therefore, they may be relatively close to each other at certain positions. When the temperature rises and a hot spot effect occurs after the solar cell is blocked, the adjacent first conductive region 100 and second conductive region 200 will preferentially form a soft breakdown region from the relatively close position to disperse the heat, reduce the hot spot temperature, and avoid the risk of fire. Moreover, during the period when the hot spot effect does not occur, the relatively close position does not affect the normal use of the solar cell.

[0086] It should be noted that since the undulation of the concave-convex shape of at least one of the first boundary 4 and the second boundary 5 described above is periodically distributed, the aforementioned convex structure 15 is also uniformly distributed in the boundary. Therefore, the soft breakdown area is also uniformly distributed on the boundary along the second direction Y, which can uniformly disperse the heat generated and further improve the effect of preventing hot spots.

[0087] In some embodiments, refer to Figure 1 , Figure 2 and Figure 9 In the battery cell, along the first direction X, the aforementioned third boundary 16 and / or fourth boundary 17 are periodically distributed. Since the interconnect 2 appears periodically along the first direction, the corresponding insulating part below the interconnect also appears periodically, which helps to improve the pull-out force between the periodically appearing insulating part and the first conductive area.

[0088] For example, Figure 2 and Figure 9In this context, the periodic distribution can refer to the same edge of the battery cell extending along the second direction Y. The uneven morphology of the boundary of the first conductive region 100 of the battery cell extending along the second direction Y is the same for the side of the same edge, and the uneven morphology of the boundary of the first conductive region 100 of the battery cell extending away from the same edge is the same for the side of the same edge. However, the uneven morphology of the boundary of the first conductive region 100 of the battery cell extending along the second direction Y along the same edge is different from the uneven morphology of the boundary of the first conductive region of the battery cell extending away from the same edge along the second direction Y.

[0089] The periodic distribution here is similar to the explanation and beneficial effect of the aforementioned periodic distribution of the first boundary and / or the second boundary along the first direction, and the relevant parts can be referred to each other.

[0090] In some embodiments, refer to Figure 5 The first conductive region between the first sub-conductive region and the second sub-conductive region is a middle first conductive region, which is recessed relative to the first sub-conductive region. A first gap region is also recessed relative to the middle first conductive region. The recess depth H1 of the first gap region relative to the first sub-conductive region is less than or equal to 3000 nm. The first sub-conductive region is the furthest point from the semiconductor substrate in the solar cell, and the first gap region is the closest point to the interior of the semiconductor substrate. The smaller recess depth H1 between them indicates a smaller unevenness on the backlight side of the semiconductor substrate, which can reduce defects such as film breaks on the backlight side of the semiconductor substrate and appropriately increase the film thickness on the backlight side of the semiconductor substrate, thus improving the passivation effect of the solar cell. Furthermore, when a small leakage current is transmitted through adjacent first and second conductive regions, the smaller recess depth H1 of the gap region relative to the second conductive region results in a shorter leakage current transmission distance and better hot spot prevention.

[0091] Furthermore, the recess depth H1 of the first spacing region relative to the first sub-conductive region is 500nm to 3000nm. If the recess depth H1 is too small, it may introduce short circuit risk. Therefore, the recess depth H1 in this application takes into account both low short circuit risk and good passivation effect.

[0092] For example, the recess depth H1 of the first spacing region relative to the first sub-conductive region can be 3000nm, 2800nm, 2500nm, 2200nm, 2000nm, 1700nm, 1500nm, 1200nm, 1000nm, 900nm, 500nm, or 200nm.

[0093] It should be noted that in determining the depth H1 of the depression, a reference can be used. Figure 5 As shown, the height difference between any second conductive region 200 away from the surface of the semiconductor substrate 1 and any spacer region 300 away from the surface of the semiconductor substrate 1 can be any one of the height differences in the battery cell, or the arithmetic mean of two or more height differences.

[0094] In some embodiments, refer to Figure 5 The first conductive region of the solar cell may include: a semiconductor substrate 1 and a first doped layer (such as an N-type doped polysilicon layer 3) and a back passivation layer 12 sequentially disposed on the semiconductor substrate 1, with the first doped layer close to the semiconductor substrate. The second conductive region of the solar cell includes: a semiconductor substrate 1 and a second doped layer (such as a P-type doped polysilicon layer 10) and a back passivation layer 12 sequentially disposed on the semiconductor substrate 1, with the second doped layer close to the semiconductor substrate. The first and second doped layers have opposite conductivity types, one being a P-type doped layer and the other an N-type doped layer. The spacer region 300 includes the semiconductor substrate 1 and the back passivation layer 12 sequentially disposed on the semiconductor substrate 1, or in other words, the back passivation layer 12 is disposed on the side of the first doped layer, the second doped layer, and the spacer region 300 away from the semiconductor substrate 1.

[0095] In some embodiments, Figure 5 The solar cell may further include a tunneling oxide layer 2 stacked with the first doped layer and located in the first conductive region 100, and a tunneling oxide layer 2 stacked with the second doped layer and located in the second conductive region 200. The tunneling oxide layer 2 is closer to the semiconductor substrate 1. Figure 5 The solar cell may also include a front passivation layer 8 sequentially stacked on the light-facing side of the semiconductor substrate 1. In some examples, a front antireflection layer is also disposed on the side of the front passivation layer 8 facing away from the semiconductor substrate 1 to provide a good passivation and antireflection effect on the light-facing side of the semiconductor substrate 1. The materials of the passivation layer and antireflection layer mentioned in this application can be selected from silicon nitride, aluminum oxide, etc., and there is no limitation on the specific materials. It should be noted that... Figure 5 In this process, the tunneling oxide layer located in the first conductive region and the tunneling oxide layer located in the second conductive region can be formed in different process steps.

[0096] Figure 5 The battery cell may also include an electrode structure located on the side of the back passivation layer 12 away from the semiconductor substrate 1. The electrode structure includes an electrode structure located in the first conductive region 100 for collecting and transporting charge carriers within the first conductive region 100, and an electrode structure located in the second conductive region 200 for collecting and transporting charge carriers within the second conductive region 200.

[0097] This application also provides a method for preparing a photovoltaic module, used to prepare any of the aforementioned photovoltaic modules. The method for preparing the photovoltaic module may include the following steps.

[0098] Step S1: Provide a plurality of battery cells. The first surface of the battery cells includes a plurality of conductive regions distributed sequentially along a first direction. The conductive regions extend along a second direction. The concave and convex morphologies of the first and second boundaries of adjacent conductive regions of the same polarity that are disposed opposite to each other extend along the second direction are different. For details regarding solar cells, please refer to the aforementioned records. To avoid repetition, the steps will not be repeated here.

[0099] Step S2: The interconnect is disposed on the battery cell; the interconnect passes through the adjacent conductive regions of the same polarity and extends along the first direction.

[0100] Interconnectors can be installed on the battery cells via electrical connections such as welding.

[0101] The following is about Figure 4 The fabrication method of the shown solar cell is briefly described. The semiconductor substrate can be a silicon substrate, etc.

[0102] The first step is to perform wet polishing on the silicon substrate. The wet polishing scheme mainly includes two steps: cleaning and alkaline polishing. Specifically, the cleaning step can be: (1) using SC1 (Standard Clean 1) in the RCA cleaning (industrial standard wet cleaning) process for cleaning. (2) then neutralizing the residual chemicals from the SC1 cleaning by rinsing with deionized water; the alkaline polishing step can be: (1) using KOH to remove the surface damage layer caused by cutting, and the surface of the silicon substrate is polished; (2) then performing high-efficiency SC1 cleaning; (3) using SC2 (Standard Clean 2 in industrial standard wet cleaning) to remove the residual metal ions; (4) finally cleaning with 5% wt (mass concentration 5%) hydrofluoric acid to complete the polishing of the silicon substrate surface. The polishing thickness of the front and back sides of the silicon substrate is 5μm to 10μm, and the polished silicon substrate surface forms a silicon substrate with different crystal orientations.

[0103] The second step involves depositing a tunneling oxide layer 2 and an N-type doped polysilicon layer 3 using an LPCVD (low-pressure chemical vapor deposition) device. A mask layer is also deposited on the N-type doped polysilicon layer 3. The thickness of the tunneling oxide layer 2 can be approximately 3 nm; the thickness of the N-type doped polysilicon layer 3 can be approximately 100 nm; and the thickness of the mask layer can be approximately 300 nm. The mask layer can be made of silicon nitride. Specifically, the tunneling oxide layer 2 is first prepared in an LPCVD device, followed by the deposition of polysilicon, and then the N-type doped polysilicon layer 3 is prepared using a diffusion device.

[0104] The third step involves using a third laser to remove portions of the N-type doped polysilicon layer 3 located within the second conductive region, as well as portions of the mask layer located within the second conductive region, thus exposing the silicon substrate within the second conductive region. The third laser can be selected with a wavelength of approximately 532 nm and a pulse width of picosecond. The power density of the third laser can be 200 mJ / cm². 2 The overlap rate of the third laser spot is approximately 60%. Figure 8 This is a schematic optical microscope image of the boundary of the N-type doped polycrystalline silicon layer 3 near the second conductive region. (Refer to...) Figure 8 After the third laser breaks the connection and wet etching is performed, a concave-convex morphology extending along the second direction Y will be formed at the boundary of the first conductive region near the second conductive region.

[0105] The fourth step involves forming a solid intrinsic amorphous silicon layer 6 and a p-type doped amorphous silicon layer 7. A front passivation layer 8 and a front antireflection layer 9 are then formed on the front side of the silicon substrate. The front passivation layer 8 is an intrinsic amorphous silicon layer, and the thicknesses of both the intrinsic amorphous silicon layer 6 and the front passivation layer 8 can be approximately 10 nm. The thickness of the p-type doped amorphous silicon layer 7 can be approximately 40 nm. The front antireflection layer 9 can be made of SiN. x (Silicon nitride), its thickness can be around 50nm.

[0106] The fifth step involves using a fourth laser to pattern the intrinsic amorphous silicon layer 6 and the p-type doped amorphous silicon layer 7, forming a notch located in the first conductive region. The width of the notch along the first direction can be approximately 180 μm. The wavelength of the fourth laser is approximately 532 nm, the pulse width is picoseconds, and the power density used can be 120 mJ / cm². 2 The fourth laser uses a single spot with a size of approximately 180 μm. The spot overlap rate of the fourth laser is about 10%. Under an optical microscope, the boundary of the second conductive region near the first conductive region after the fourth laser process also shows an uneven morphology extending along the second direction (Y). The spot overlap rate of the fourth laser differs from that of the third laser; therefore, the uneven morphology of the boundary of the first conductive region extending along the second direction differs in shape from the uneven morphology of the boundary of the second conductive region extending along the second direction.

[0107] Step 6: A full-layer transparent conductive layer 11 is formed on the side of the N-type doped polycrystalline silicon layer 3 and the P-type doped amorphous silicon layer 7 facing away from the silicon substrate 1. Using a third laser, an opening is formed in the localized region where the N-type doped polycrystalline silicon layer 3 and the P-type doped amorphous silicon layer 7 overlap in the transparent conductive layer 11, the P-type doped amorphous silicon layer 7, and the intrinsic amorphous silicon layer 6. The width of the opening along the first direction X can be approximately 100 μm. The transparent conductive layer 11 can be deposited using PVD (physical vapor deposition) equipment, and its thickness can be approximately 120 nm.

[0108] The seventh step is to prepare the electrode structure, which can be done using screen printing.

[0109] In some embodiments, for Figure 5 The battery cell shown is referenced. Figure 2 The aforementioned step S1 may include: forming a second doped layer (e.g., on the back side of the semiconductor substrate of at least one of the aforementioned plurality of solar cells) Figure 2 and Figure 5 The P-type doped polysilicon layer 10 in the text can refer to a second doped layer formed on the back side of a semiconductor substrate. The formation of the second doped layer can be achieved through deposition or other methods, and the specific formation method is not limited. It should be noted that during the process of forming the second doped layer, a tunneling oxide layer 2 located between the second doped layer and the semiconductor substrate can be formed simultaneously. Next, a first laser is used to form the second doped layer within the first sub-conductive region 201 and the second sub-conductive region 202. The first laser acts on the intermediate first conductive region (e.g., it could be...). Figure 2 The first laser spot extends along the second direction Y, forming two different contour lines, with the first laser beam extending from the central conductive region 100 and the positions corresponding to the first and second spacer regions 301 and 302 on either side of the central conductive region in the first direction X. Under the action of the first laser (which may include a cleaning process following the first laser), the central conductive region and the second doped layer at the positions corresponding to the first and second spacer regions 301 and 302 on either side of the central conductive region in the first direction X are removed from the back side of the semiconductor substrate, leaving the central conductive region and the positions corresponding to the first and second spacer regions 301 and 302 on either side of the central conductive region exposed on the back side of the semiconductor substrate. Therefore, the outline of the first laser spot extending along the second direction and close to the first sub-conductive region 201 will affect the unevenness of the first boundary 4 of the first sub-conductive region 201 extending along the second direction Y, and the outline of the first laser spot extending along the second direction and close to the second sub-conductive region 202 will affect the unevenness of the second boundary 5 of the second sub-conductive region 202 extending along the second direction Y. Therefore, it is easy to form the first boundary 4 of the first sub-conductive region 201 and the second boundary 5 of the second sub-conductive region 202 with different unevenness along the second direction Y.

[0110] It should be noted that in the process of forming the second doped layer in the first sub-conductive region 201 and the second sub-conductive region 202 using the first laser, the tunneling oxide layer 2 in the first sub-conductive region 201 and the second sub-conductive region 202 can also be formed using the first laser.

[0111] against Figure 5 The battery cells shown are referenced here. Figure 2 Next, on the back side of the semiconductor substrate, at the corresponding positions of the intermediate first conductive region, the first spacing region 301, and the second spacing region 302, and on the second doped layer within the first sub-conductive region 201 and the second sub-conductive region 202, a first doped layer (e.g., Figure 2 and Figure 5 In the N-type doped polysilicon layer 3), the first doped layer and the second doped layer have different conductivity types; one is an N-type doped layer and the other is a P-type doped layer. In this case, the first doped layer covers the second doped layer located within the first sub-conductive region 201 and the second sub-conductive region 202. It should be noted that during the process of forming the first doped layer, the tunneling oxide layer 2 located between the first doped layer and the semiconductor substrate can be formed simultaneously. For... Figure 5 The battery cells shown are referenced here. Figure 2 A second laser is used to form a first doped layer within the intermediate first conductive region. This second laser acts on the positions corresponding to the first sub-conductive region 201, the second sub-conductive region 202, the first spacer region 301, and the second spacer region 302. Under the action of the second laser (which may include a cleaning process following the second laser), the portion of the first doped layer covering the second doped layer within the first sub-conductive region 201 and the second sub-conductive region 202 is removed, thus exposing the second doped layer within the first sub-conductive region 201 and the second conductive region 202 again. The specific details of the first sub-conductive region, second sub-conductive region, intermediate first conductive region, first spacer region, and second spacer region can be found in the preceding description. Figure 5 , Figure 1 and Figure 2 Related records. Along the first direction X, the first conductive region 100 and the second conductive region 200 are alternately distributed. The morphologies of the two contour lines of the second laser spot extending along the second direction Y are different. This second laser (e.g. Figure 2 The spot of the second laser (the one at the top) extends along the second direction Y and acts on the contour line of the first interval region 301 (e.g., Figure 2 The lower contour line of the uppermost second laser spot will affect the unevenness of the third boundary 16 of the middle first conductive region extending along the second direction Y, while another second laser (e.g., Figure 2 The spot of the second laser (from top to bottom) extends along the second direction and acts on the contour line of the second interval region 302 (e.g., Figure 2The upper contour line of the second laser spot (from top to bottom) affects the unevenness of the fourth boundary 17 of the intermediate first conductive region extending along the second direction Y. Since the third boundary 16 and fourth boundary 17 of each intermediate first conductive region are affected by the different shapes of the two contour lines of the second laser spot extending along the second direction Y, it is easy to form the third boundary 16 and fourth boundary 17 of the first conductive region 100 with different unevenness along the second direction Y. Afterwards, a passivation layer is formed on the entire back side of the solar cell.

[0112] It should be noted that the area formed by the first laser can be formed by a large light spot or by multiple paths of a small light spot; this application does not limit this.

[0113] It should be noted that in the process of forming the first doped layer in the intermediate first conductive region using the second laser, the tunneling oxide layer 2 in the intermediate first conductive region can also be formed using the second laser.

[0114] It should be noted that, Figure 5 Other process steps of the shown solar cell are similar to Figure 4 The methods for preparing the battery cells shown are somewhat similar, and will not be repeated here to avoid repetition.

[0115] It should be noted that, as mentioned above Figure 4 The fabrication methods of the solar cells shown are generally similar. One reason for the difference in the uneven morphology of the boundary of the conductive region extending along the second direction Y in the photovoltaic module mentioned in this application is that during the laser processing of the conductive region, differences in the overlap rate of the laser spot or the different shapes of the two contour lines extending along the second direction Y of the laser spot lead to differences in the shape of the final conductive region boundary. The differences in the uneven morphology of the boundary extending along the second direction Y include, but are not limited to, the examples mentioned above.

[0116] In another embodiment, for Figure 11 and Figure 12 The solar cell shown is prepared by applying a doped layer to the front side, followed by removing the doped layer in the spacer region using laser (or possibly wet cleaning) to obtain a conductive region extending along the second direction. Other steps can be referred to the process method of the foregoing embodiments.

[0117] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0118] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A photovoltaic module, characterized in that, include: Multiple battery strings connected in series and / or in parallel, the battery strings including interconnects and a number of battery cells; The first surface of the battery cell includes a plurality of conductive regions distributed sequentially along a first direction. The conductive regions extend along a second direction. The first and second boundaries of adjacent conductive regions of the same polarity have different convex and concave morphologies as they extend along the second direction, and the regions between adjacent conductive regions of the same polarity are recessed. The interconnecting element passes through the adjacent conductive regions of the same polarity and extends along the first direction.

2. The photovoltaic module according to claim 1, characterized in that, Along the first direction in the battery cell, the oppositely arranged first boundary and second boundary are periodically distributed.

3. The photovoltaic module according to claim 1 or 2, characterized in that, The undulations of the concave-convex shape of at least one of the first boundary and the second boundary along the second direction are periodically distributed.

4. The photovoltaic module according to any one of claims 1 to 3, characterized in that, The shape of the first boundary or the second boundary is wavy; and / or, The first boundary or the second boundary includes at least one of the following: an arc segment, a broken line segment, and a straight line segment.

5. The photovoltaic module according to any one of claims 1 to 4, characterized in that, The first boundary or the second boundary is the outline of the adjacent conductive regions of the same polarity disposed opposite each other on the first surface, and the outline extends along the second direction.

6. The photovoltaic module according to any one of claims 1 to 4, characterized in that, The first boundary and / or the second boundary are inclined slope structures along the thickness direction of the battery cell, and the two ends of the slope structure form two contour lines extending along the second direction, the two contour lines having the same concave-convex shape trend; or, The first boundary and / or the second boundary includes a gentle slope structure inclined along the thickness direction of the battery cell, and a protruding structure protruding from the gentle slope structure. The protruding structure is opposite to the contour line of the gentle slope structure, and the contour line is similar to the contour line of the gentle slope structure. The contour line extends along the second direction.

7. The photovoltaic module according to any one of claims 1 to 6, characterized in that, The different morphologies of the first and second boundaries of the adjacent conductive regions of the same polarity extending along the second direction include: The unevenness of the first boundary is different from that of the second boundary; and / or, The concavity / convexity frequency of the first boundary is different from that of the second boundary.

8. The photovoltaic module according to any one of claims 1 to 7, characterized in that, The plurality of conductive regions include a plurality of first conductive regions and a plurality of second conductive regions alternately distributed along the first direction. The first conductive regions and the second conductive regions have different polarities, and the second conductive regions are recessed relative to the first conductive regions. Adjacent first conductive regions form the first boundary and the second boundary with the intermediate second conductive region, respectively. The intermediate second conductive region is the second conductive region between adjacent first conductive regions.

9. The photovoltaic module according to claim 8, characterized in that, The second conductive region includes a semiconductor substrate, a second doped layer disposed on the semiconductor substrate, and a transparent conductive layer, wherein the second doped layer and the transparent conductive layer extend to cover a portion of the first conductive region; The first conductive region includes the semiconductor substrate and a first doped layer, a second doped layer and a transparent conductive layer sequentially disposed on the semiconductor substrate, and at least the transparent conductive layer is provided with a disconnection opening in the overlapping region of the second doped layer and the first doped layer; The interconnecting element passes through the transparent conductive layer of the first conductive region.

10. The photovoltaic module according to any one of claims 1 to 7, characterized in that, In the battery cell, a recessed spacer region is provided between adjacent conductive regions, and the adjacent conductive regions are conductive regions of the same polarity. The spacer region extends along the second direction, and the adjacent conductive regions and the spacer region between the adjacent conductive regions respectively form the first boundary and the second boundary.

11. The photovoltaic module according to claim 10, characterized in that, The first side is the back side of the battery cell, the conductive region includes a semiconductor substrate and a first doped layer and a back passivation layer sequentially disposed on the semiconductor substrate, and the spacing region includes the semiconductor substrate and the back passivation layer disposed on the semiconductor substrate.

12. The photovoltaic module according to claim 10 or 11, characterized in that, The first side is the front side of the battery cell, the conductive region includes a semiconductor substrate, a second doped layer and a front passivation layer sequentially disposed on the semiconductor substrate, and the spacing region includes the semiconductor substrate and the front passivation layer disposed on the semiconductor substrate.

13. The photovoltaic module according to any one of claims 1 to 7, characterized in that, The plurality of conductive regions include a plurality of first conductive regions and a plurality of second conductive regions alternately distributed along the first direction. The first conductive regions and the second conductive regions have different polarities. Adjacent second conductive regions are respectively first sub-conductive regions and second sub-conductive regions. The first conductive region between the first sub-conductive regions and the second sub-conductive regions is an intermediate first conductive region. A first interval region is recessed between the first sub-conductive regions and the intermediate first conductive regions. A second interval region is recessed between the second sub-conductive regions and the intermediate first conductive regions. The first sub-conductive regions and the first interval region form the first boundary. The second sub-conductive regions and the second interval region form the second boundary.

14. The photovoltaic module according to claim 13, characterized in that, The first conductive region includes a semiconductor substrate and a first doped layer and a back passivation layer sequentially disposed on the semiconductor substrate. The second conductive region includes the semiconductor substrate and a second doped layer and a back passivation layer sequentially disposed on the semiconductor substrate. The first doped layer and the second doped layer have different doping types. The spacer region includes the semiconductor substrate and the back passivation layer.

15. The photovoltaic module according to claim 13, characterized in that, The intermediate first conductive region and the first interval region form a third boundary, and the intermediate first conductive region and the second interval region form a fourth boundary. The third boundary and the fourth boundary have different concave and convex shapes as they extend along the second direction. The photovoltaic module further includes an insulating element that covers the intermediate first conductive region along the first direction, as well as a portion of the third boundary and a portion of the fourth boundary; along the first direction, the insulating element and the interconnecting element electrically connected to the second conductive region at least partially overlap.

16. The photovoltaic module according to claim 15, characterized in that, In the battery cell, the third boundary and / or the fourth boundary are periodically distributed along the first direction.

17. The photovoltaic module according to claim 15 or 16, characterized in that, The first boundary and the third boundary have different concave and convex shapes extending along the second direction.

18. The photovoltaic module according to any one of claims 15 to 17, characterized in that, The first boundary and the third boundary form a plurality of convex structures facing each other and approaching each other along the first direction; and / or, The second boundary and the fourth boundary form several convex structures facing each other and close to each other along the first direction.

19. The photovoltaic module according to any one of claims 15 to 17, characterized in that, The second boundary and the fourth boundary have different concave and convex shapes extending along the second direction.

20. The photovoltaic module according to any one of claims 13 to 19, characterized in that, The intermediate first conductive region is recessed relative to the first sub-conductive region, and the first interval region is recessed relative to the intermediate first conductive region. The recess depth of the first interval region relative to the first sub-conductive region is less than or equal to 3000 nm.

21. The photovoltaic module according to any one of claims 1 to 20, characterized in that, The battery cell further includes a connecting portion, which is continuously or intermittently disposed on a portion of the conductive area and is used to electrically connect the conductive area to the interconnect.

22. A method for preparing a photovoltaic module, characterized in that, The photovoltaic module applied to any one of claims 1 to 21 comprises: A plurality of battery cells are provided, wherein a first surface of the battery cells includes a plurality of conductive regions distributed sequentially along a first direction, the conductive regions extending along a second direction, and the concave and convex morphologies of the first and second boundaries of adjacent conductive regions of the same polarity extending along the second direction are different. An interconnect is disposed on the battery cell; the interconnect passes through the adjacent conductive regions of the same polarity and extends along the first direction.

23. The method for preparing a photovoltaic module according to claim 22, characterized in that, The provision of multiple battery cells includes: A second doped layer is formed on the back side of the semiconductor substrate of at least one of the plurality of solar cells; A first laser is used to form a second doped layer within a first sub-conductive region and a second sub-conductive region. The first laser acts on the middle first conductive region and on the positions corresponding to the first and second interval regions located on both sides of the middle first conductive region in the first direction. The two contour lines of the first laser spot extending along the second direction have different concave and convex shapes. A first doped layer is formed at the corresponding positions of the intermediate first conductive region, the first interval region, and the second interval region, as well as on the second doped layer within the first sub-conductive region and the second sub-conductive region. The first doped layer and the second doped layer have different conductivity types. The first doped layer in the intermediate first conductive region is formed by using a second laser. The second laser acts on the positions corresponding to the first sub-conductive region, the second sub-conductive region, the first interval region, and the second interval region. The two contour lines of the second laser spot extending along the second direction have different concave and convex shapes. A back passivation layer is formed on the outermost layer of the battery cell.

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