Back-contact cell, manufacturing method therefor, and photovoltaic module

Abstract

A back-contact cell, a manufacturing method therefor, and a corresponding photovoltaic module. The back-contact cell comprises a semiconductor substrate, first doped portions, second doped portions and interconnection structures. A first surface of the semiconductor substrate is provided with first regions and second regions which are alternately distributed. The first doped portions are located in the first regions. The second doped portions include second doped portions A located in the second regions and second doped portions B located above the part of the first doped portions facing away from the semiconductor substrate. The second doped portions and the first doped portions have opposite conductivity types. The second doped portions B and the first doped portions are spaced apart. The plurality of interconnection structures are located on the side of the first doped portions facing away from the semiconductor substrate, and are electrically connected to the first doped portions. At least part of each second doped portion B is located between a corresponding interconnection structure and a first doped portion, and the second doped portions B are insulated from the interconnection structures. Therefore, the present application improves the manufacturing efficiency of back-contact cells, reduces the production cost, and increases the production capacity of back-contact cells.

Description

Back contact cell, manufacturing method thereof and photovoltaic module TECHNICAL FIELD

[0001] The present application relates to the technical field of photovoltaics, and in particular to a back contact cell, a manufacturing method thereof and a photovoltaic module. BACKGROUND

[0002] A solar cell is a device capable of converting solar light energy into electrical energy. The solar cell in which the positive electrode and the negative electrode are both located on the back surface of the cell is a back contact cell. Compared with a double-sided contact solar cell, the front surface of the back contact cell is not shielded by a metal electrode, so that the light-receiving surface side of the back contact cell has a higher light utilization rate, and thus the back contact cell has a higher short-circuit current and a higher photoelectric conversion efficiency. The back contact cell is one of the technical directions for realizing high-efficiency crystalline silicon cells.

[0003] However, the manufacturing efficiency of the existing back contact cell is low, which is not conducive to improving the manufacturing capacity of the back contact cell. SUMMARY

[0004] The present application aims to provide a back contact cell, a manufacturing method thereof and a photovoltaic module, for improving the manufacturing efficiency of the back contact cell and increasing the manufacturing capacity of the back contact cell.

[0005] To achieve the above-mentioned purpose, in a first aspect, the present application provides a back contact cell, comprising a semiconductor substrate, a first doped portion, a second doped portion and a plurality of interconnection structures. The semiconductor substrate has opposite first and second surfaces. The first surface has first and second regions alternatingly distributed. The first doped portion is located in the first region. The second doped portion includes a second doped portion A located in the second region and a second doped portion B located above a portion of the first doped portion away from the semiconductor substrate. The second doped portion and the first doped portion have opposite conductive types. The second doped portion B and the first doped portion are spaced apart in the thickness direction of the semiconductor substrate. The plurality of interconnection structures are located on the side of the first doped portion away from the semiconductor substrate, and the interconnection structures are electrically connected to the first doped portion. At least part of each second doped portion B is located between the first doped portion and the corresponding interconnection structure, and the second doped portion B and the interconnection structure are insulated from each other.

[0006] In the back contact cell, the first doped part and the second doped part have opposite conductive types. The first doped part is located on the first region of the first surface of the semiconductor substrate, and the plurality of interconnection structures are located on the side of the first doped part away from the semiconductor substrate and are electrically connected to the first doped part. The second doped part includes a second doped part A located on the second region. When the back contact cell is in operation, the electron-hole pairs generated by the semiconductor substrate after absorbing photons are separated by the first doped part and the second doped part A, one of the electron and the hole is collected by the first doped part and is led out by the interconnection structure electrically connected to the first doped part, and the other of the electron and the hole is collected by the second doped part A and is led out, forming a photoelectric current.

[0007] In addition, in the back contact cell, the second doped part includes not only the second doped part A having the carrier separation and collection functions, but also a second doped part B located above the part of the first doped part away from the semiconductor substrate. The second doped part B and the first doped part are spaced apart along the thickness direction of the semiconductor substrate, which helps to prevent the generation of leakage current between the second doped part B and the first doped part having the opposite conductive type. In addition, at least part of each second doped part B is located between the corresponding interconnection structure having the opposite conductive type and the first doped part, but the second doped part B is insulated from the interconnection structure, so that the generation of leakage current between the second doped part B and the interconnection structure can be prevented, and the back contact cell has high working performance. In the actual manufacturing process, the second doped part is formed by selectively etching the second doped semiconductor layer arranged on the first doped part and the second region. Before the selective etching, the mask material formed on the side of the second doped semiconductor layer away from the semiconductor substrate needs to be selectively processed by laser engraving or other processes, so that the part of the mask material that is not processed forms a mask layer for protecting the second doped part. It can be seen that the formation range of the second doped part determines the range of the mask material that needs to be processed. Therefore, when the second doped part includes not only the second doped part A but also the second doped part B located above the part of the first doped part away from the semiconductor substrate, the part of the mask material corresponding to the second doped part B does not need to be engraved, so that the processing time of the mask material and the second doped part B can be shortened, the manufacturing efficiency of the back contact cell is improved, the production cost is reduced, and the manufacturing capacity of the back contact cell is increased.

[0008] As a possible implementation, the back contact cell further includes a first insulating layer located between the first doped part and the second doped part B.

[0009] In the technical solution, the first insulating layer is a non-conductive film layer. Therefore, when the first insulating layer is located between the first doped part and the second doped part B, the first doped part can be insulated from the second doped part B of the opposite conduction type through the first insulating layer, so as to prevent the leakage current between the two, and ensure that the back contact cell has high working performance while improving the efficiency of selective processing of the mask material.

[0010] As a possible implementation, the back contact cell further includes a second insulating layer. The second insulating layer covers the side of the first doped part away from the semiconductor substrate and the side of the second doped part away from the semiconductor substrate. The interconnection structure is insulated from the second doped part B through the second insulating layer. In this case, the presence of the second insulating layer can prevent the leakage current between the second doped part B and the interconnection structure, and ensure that the back contact cell has high working performance.

[0011] As a possible implementation, when the material of the first doped part includes silicon, the first insulating layer includes a doped silicon glass layer.

[0012] In the technical solution, when the material of the first doped part includes silicon, the diffusion treatment can not only obtain the first doped part, but also form a doped silicon glass layer on the side of the first doped part away from the semiconductor substrate. Based on this, when the first insulating layer includes a doped silicon glass layer, the diffusion treatment can be performed at the same time to form at least part of the first insulating layer. This can not only prevent the leakage current between the first doped part and the second doped part B through the first insulating layer, but also improve the manufacturing efficiency of the first insulating layer and further improve the manufacturing capacity of the back contact cell.

[0013] As a possible implementation, the dielectric constant of the first insulating layer is greater than or equal to 4.5 and less than or equal to 6.5. In this case, it is beneficial to prevent the first insulating layer from having poor insulation performance due to a small dielectric constant, and to ensure that the first doped part and the second doped part B can be insulated from each other through the first insulating layer.

[0014] As a possible implementation, the resistivity of the first insulating layer is greater than or equal to 5×10 9 Ω·cm and less than or equal to 5×10 12 Ω·cm. The beneficial effects in this case can be referred to the beneficial effect analysis of the dielectric constant of the first insulating layer being greater than or equal to 4.5 and less than or equal to 6.5, which will not be described here.

[0015] As a possible implementation, the second insulating layer includes a surface passivation layer. In this case, at least part of the second insulating layer can be formed at the same time as the surface passivation treatment on the back side of the back contact cell, which helps to improve the manufacturing efficiency of the second insulating layer and further improve the manufacturing capacity of the back contact cell while ensuring that the second doped part B and the interconnection structure can be prevented from generating leakage current.

[0016] As a possible implementation, the ratio of the depth to which the interconnection structure extends into the second insulating layer to the thickness of the second insulating layer is greater than or equal to 0 and less than or equal to 0.85.

[0017] With the above technical solution, since the second insulating layer has a certain thickness, and in the case where the minimum distance between the side of the interconnection structure close to the semiconductor substrate and the second doped part B of the opposite conductive type is greater than the anti-leakage distance, the leakage current between the second doped part B and the interconnection structure can be prevented. Based on this, when the ratio of the depth to which the interconnection structure extends into the second insulating layer to the thickness of the second insulating layer is greater than or equal to 0 and less than or equal to 0.85, the precision of the process parameters and the composition of the conductive paste required for manufacturing the interconnection structure can be reduced while ensuring that the second doped part B and the interconnection structure will not generate leakage current, thereby reducing the manufacturing difficulty of the interconnection structure.

[0018] As a possible implementation, the thickness of the second insulating layer is greater than or equal to 60 nm and less than or equal to 150 nm.

[0019] With the above technical solution, the thickness of the second insulating layer is within the above range, which helps to prevent the minimum distance between the side of the interconnection structure close to the semiconductor substrate and the second doped part B of the opposite conductive type from being too small after the interconnection structure is formed due to the small thickness of the second insulating layer, thereby ensuring that the second doped part B and the interconnection structure will not generate leakage current. In addition, it can also prevent the use of a large amount of consumables for manufacturing the second insulating layer due to the large thickness of the second insulating layer, which helps to control the manufacturing cost of the back contact cell.

[0020] As a possible implementation, the minimum distance between the side of the interconnection structure close to the semiconductor substrate and the second doped part B in the thickness direction of the semiconductor substrate is greater than or equal to 15 nm and less than or equal to 60 nm.

[0021] In the above technical solution, the minimum distance between the interconnection structure close to the semiconductor substrate and the second doped part B is within the range, which is beneficial to prevent the small minimum distance from resulting in poor anti-leakage effect between the second doped part B and the interconnection structure, and ensure the back contact cell to have high working performance. In addition, under the same other conditions, it is also beneficial to prevent the large minimum distance from resulting in the need to form a second insulating layer with large thickness, and thus resulting in large consumption of materials for manufacturing the second insulating layer, and is beneficial to control the manufacturing cost of the back contact cell.

[0022] As a possible implementation, the second insulating layer includes an aluminum oxide passivation layer and a silicon nitride anti-reflection layer which are sequentially stacked in the direction away from the semiconductor substrate. The side of the interconnection structure close to the semiconductor substrate is located in the silicon nitride anti-reflection layer. In this case, the interconnection structure can be at least insulated from the second doped part B with the opposite conduction type to itself through the aluminum oxide passivation layer, to prevent the generation of leakage current.

[0023] As a possible implementation, the second insulating layer is coated on the side surface and the side surface away from the semiconductor substrate of the structure composed of the first doped part and the second doped part B. In this case, the second insulating layer can wrap the second doped part B, so as to insulate the second doped part B from other conductive structures such as the interconnection structure with the opposite conduction type to itself and located on the side or above the second doped part B, to prevent the generation of leakage current.

[0024] As a possible implementation, the second insulating layer is coated on the side surface and the side surface away from the semiconductor substrate of the structure composed of the first doped part and the second doped part B, and extends to the side surface and the side surface away from the substrate of the second doped part A. In this case, the second insulating layer can wrap the first doped part, the second doped part A and the second doped part B formed on the side of the first surface of the semiconductor substrate, to prevent the problem of short circuit caused by the opposite lapping after the formation of the interconnection structure and the electrode structure, and to prevent the short circuit caused by the contact between the opposite doped parts in the process of packaging and extruding the photovoltaic module formed by the back contact cells provided by the present application. In addition, in the case where the second insulating layer includes a surface passivation layer, when the second insulating layer is coated on the side surface and the side surface away from the semiconductor substrate of the structure composed of the first doped part and the second doped part B, and extends to the side surface and the side surface away from the substrate of the second doped part A, the second insulating layer can simultaneously perform passivation treatment on the side surface and the side surface away from the semiconductor substrate of the structure composed of the first doped part and the second doped part B, and the side surface and the side surface away from the substrate of the second doped part A to which the second insulating layer extends, to greatly reduce the surface defects on the back surface side of the back contact cell, and reduce the carrier recombination rate.

[0025] As a possible implementation, in the case where the first doped part and the second doped part A are alternately and spacedly distributed in a strip shape, the first doped part and the second doped part A each include a plurality of strip regions. The strip regions included by the first doped part and the strip regions included by the second doped part A are spacedly and non-intersectingly distributed, and have a spacing region between any two adjacent strip regions. At least one second doped part B has a projection on the first face only in a partial region of a projection on the first face of the strip regions included by the first doped part; or, at least one second doped part B has a projection on the first face in a partial region of a projection on the first face of the strip regions included by the first doped part, and the second doped part B extends to the spacing region along a width direction of the strip region.

[0026] In the case of the above technical solution, the forming range of the second doped portion B on the first side has at least the above two embodiments. When the orthographic projection of at least one second doped portion B on the first side is located only in the partial area of the orthographic projection of the strip-shaped region included in the first doped portion on the first side, the part of the first doped portion located below the second doped portion B can be electrically isolated by the spacing region and the second doped portion A of the opposite conductivity type, which is conducive to reducing the leakage current of the back contact cell. When the orthographic projection of at least one second doped portion B on the first side is located in the partial area of the orthographic projection of the strip-shaped region included in the first doped portion on the first side, and the second doped portion B extends to the spacing region along the width direction of the strip-shaped region, the forming range of the second doped portion B above the first side is relatively large, which can further shorten the processing time of the mask material, improve the manufacturing efficiency of the back contact cell, reduce the production cost, and increase the manufacturing capacity of the back contact cell. At the same time, compared with the case where the orthographic projection of at least one second doped portion B on the first side is located only in the partial area of the orthographic projection of the strip-shaped region included in the first doped portion on the first side, when the second doped portion B extends to the spacing region along the width direction of the strip-shaped region, the second doped portion B can form an electrical contact with the side wall of the first doped portion, which is conducive to making the second doped portion B and the first doped portion form a leakage current, and the distance between the second doped portion B and the second doped portion A is small, which is conducive to electrically connecting the local area of the first doped portion through the local area of the second doped portion B and the second doped portion A of the opposite conductivity type, and the first doped portion and the second doped portion B (or the second doped portion B and the second doped portion A) can be electrically connected by manufacturing a local leakage point to form a built-in diode with a lower reverse breakdown voltage, which is conducive to making the back contact cell have a lower reverse breakdown voltage when it is blocked. The part of the first doped portion not corresponding to the second doped portion B can be physically isolated by the spacing region and other areas of the second doped portion A, which prevents the leakage current between the two from being too large and causing the back contact cell to have a low working efficiency, and ensures that the photovoltaic module including the back contact cell provided by the present application has a high photoelectric conversion efficiency in the forward voltage region. In the above case, the forming range of the second doped portion B on the first side has at least the above two embodiments, each of which has different advantages, which facilitates the selection of a suitable scheme according to different application scenarios and improves the applicability of the back contact cell provided by the present application in different application scenarios.

[0027] As a possible implementation, in the case that the orthographic projection of the at least one second doped portion B on the first surface is located only within a partial region of the strip-shaped region included by the first doped portion, the ratio of the width of the second doped portion B to the width of the strip-shaped region included by the first doped portion is greater than or equal to 0.1 and less than or equal to 1 along the width direction of the strip-shaped region, and / or the minimum distance between the edge of the orthographic projection of the at least one second doped portion B on the first doped portion and the edge of the strip-shaped region included by the corresponding first doped portion is greater than or equal to 0 and less than or equal to 2 mm along the width direction of the strip-shaped region.

[0028] With the above technical solution, the ratio of the width of the second doped portion B to the width of the strip-shaped region included by the first doped portion is within the above range along the width direction of the strip-shaped region, which is beneficial to prevent the time for selectively processing the mask material from being shortened to a low degree due to the small width and range of the second doped portion B, and to ensure a high manufacturing efficiency of the back contact cell. In addition, the minimum distance between the edge of the orthographic projection of the at least one second doped portion B on the first doped portion and the edge of the strip-shaped region included by the corresponding first doped portion is greater than or equal to 0 and less than or equal to 2 mm along the width direction of the strip-shaped region, which has the beneficial effects as described above with reference to the ratio of the width of the second doped portion B to the width of the strip-shaped region included by the first doped portion, and thus will not be described here again.

[0029] As a possible implementation, the ratio of the length of the second doped portion B to the length of the interconnection structure is greater than or equal to 0.1 and less than or equal to 0.9 along the length direction of the strip-shaped region.

[0030] With the above technical solution, the first current collecting electrode in electrical contact with the strip-shaped region is generally arranged above the remaining region of the strip-shaped region included by the first doped portion except the region covered by the interconnection structure along the length direction of the strip-shaped region, for collecting and leading out the carriers. Based on this, when the ratio of the length of the second doped portion B to the length of the interconnection structure is within the above range, it is beneficial to prevent the time for selectively processing the mask material from being shortened to a low degree due to the small length of the second doped portion B, and to ensure a high manufacturing efficiency of the back contact cell. In addition, it is also beneficial to prevent the distance between the second doped portion B and the first current collecting electrode with the opposite conduction type from being small due to the large ratio, to ensure that no leakage current occurs between the second doped portion B and the first current collecting electrode, and to ensure a high working efficiency of the back contact cell.

[0031] As a possible implementation, the ratio of the width of the part of the second doped portion B extending to the spacer region to the width of the spacer region is greater than or equal to 0.1 and less than or equal to 1 along the width direction of the strip-shaped region.

[0032] In the above technical solution, when the ratio of the width of the part of the second doped part B extending to the spacing region to the width of the spacing region is equal to 1, the part of the second doped part B extending to the spacing region is in contact with the adjacent second doped part A, which is beneficial to increase the leakage current between the first doped part and the second doped part, increase the reverse breakdown voltage of the back contact cell, and improve the hot spot prevention effect of the photovoltaic module including the back contact cell provided in the present application. When the ratio of the width of the part of the second doped part B extending to the spacing region to the width of the spacing region is greater than or equal to 0.1 and less than 1, the part of the second doped part B extending to the spacing region has a gap between the adjacent second doped part A, which is beneficial to control the leakage current between the first doped part and the second doped part, prevent the leakage current between the first doped part and the second doped part from being too large and causing the back contact cell to have a low working efficiency, and ensure that the photovoltaic module including the back contact cell provided in the present application has a high photoelectric conversion efficiency in the forward voltage region. In the above case, the width of the part of the second doped part B extending to the spacing region corresponds to different effects, and appropriate solutions can be selected according to different application scenarios, which is beneficial to improve the applicability of the back contact cell provided in the present application in different application scenarios.

[0033] As a possible implementation, in the case where the first doped part and the second doped part A are in an interdigital alternating and spaced distribution, the orthographic projection of the at least one second doped part B on the first face is located only in the partial region of the orthographic projection of the connecting region included in the first doped part on the first face; or the orthographic projection of the at least one second doped part B on the first face is located in the partial region of the orthographic projection of the connecting region included in the first doped part on the first face, and the second doped part B extends to the spacing region along the length direction of the strip-shaped region. In this case, the beneficial effects can be analyzed with reference to the beneficial effects of the case where the first doped part and the second doped part A are in a strip-shaped alternating and spaced distribution, and the orthographic projection of the at least one second doped part B on the first face is located only in the partial region of the orthographic projection of the strip-shaped region included in the first doped part on the first face; or the orthographic projection of the at least one second doped part B on the first face is located in the partial region of the orthographic projection of the strip-shaped region included in the first doped part on the first face, and the second doped part B extends to the spacing region along the width direction of the strip-shaped region, and details are not repeated here.

[0034] As a possible implementation, the interval region between the two adjacent strip regions is formed with a groove, and the first doped part and the second doped part B are overlapped in the groove to form a conductive channel; or, the back contact cell includes an insulating part formed in the interval region, and the part of the second doped part B corresponding to the interval region is located on one side of the insulating part and is overlapped with the first doped part to form a conductive channel. In this case, the local area of the first doped part and the second doped part B (or the second doped part B and the second doped part A) of the opposite conduction type are electrically connected through the conductive channel, and the built-in diode with lower reverse breakdown voltage can be formed by manufacturing a local leakage point, thereby facilitating the back contact cell to have a lower reverse breakdown voltage when being shielded.

[0035] As a possible implementation, the partial insulating part is formed in the local area of the interval region and between the second doped part B and the second doped part A. In this case, the second doped part B extends to the interval region and has a gap between the adjacent second doped part A, which facilitates the control of the leakage current between the first doped part and the second doped part, prevents the leakage current between them from being too large, and causes the back contact cell to have a lower working efficiency, thereby ensuring that the photovoltaic module including the back contact cell provided by the present application has a higher photoelectric conversion efficiency in the forward voltage region. Moreover, when the insulating part includes a partial surface passivation layer, the partial insulating part formed in the local area of the interval region can also passivate the local area of the interval region, reduce the number of defects, and facilitate the improvement of the photoelectric conversion efficiency of the back contact cell.

[0036] As a possible implementation, the first doped part and the second doped part B are both doped layers on the semiconductor substrate, and the second doped part B is overlapped with the side wall of the first doped part in the thickness direction to form a conductive channel.

[0037] As a possible implementation, the back contact cell further includes an interface passivation layer; the interface passivation layer is arranged between the second doped part A and the semiconductor substrate, between the second doped part B and the first doped part, and between the second doped part B and the semiconductor substrate; and the part of the interface passivation layer corresponding to the first region and the interval region is integrally continuous. In this case, the interface passivation layer facilitates the spacing of the first doped part and the second doped part B of the opposite conduction type, and facilitates the prevention of leakage. At the same time, the interface passivation layer can also passivate at least part of the surface of the interval region and the surface of the second region, reduce the carrier recombination rate on the first side, and facilitate the improvement of the photoelectric conversion efficiency of the back contact cell.

[0038] As a possible implementation, the at least one second doped portion B extends over the first doped portion to the spacing region and is continuously arranged with the second doped portion A. In this case, the beneficial effects can be analyzed with reference to the beneficial effects of the part of the second doped portion B extending to the spacing region with the width of the second doped portion B equal to the width of the spacing region, which will not be repeated here.

[0039] As a possible implementation, in the case where the orthographic projection of the second doped portion B on the first face is located only in the part of the orthographic projection of the connecting region included in the first doped portion on the first face, the distance between the edge of the orthographic projection of the second doped portion B on the first doped portion and the edge of the connecting region included in the first doped portion along the length direction of the strip-shaped region is greater than or equal to 0 and less than or equal to 2 mm.

[0040] In the case of the above technical solution, the distance between the edge of the orthographic projection of the second doped portion B on the first doped portion and the edge of the connecting region included in the first doped portion along the length direction of the strip-shaped region is within the above range, which is beneficial to prevent the time for selectively processing the mask material from being shortened to a lower degree due to the smaller width of the second doped portion B caused by the larger distance, and to ensure the higher manufacturing efficiency of the back contact cell. In addition, it is also beneficial to prevent the width of the mask material to be removed above the distance between the second doped portion B and the second doped portion A along the length direction of the strip-shaped region from being smaller due to the smaller distance, which is beneficial to reduce the precision requirement for selectively processing the mask material and to reduce the difficulty of selectively processing the mask material.

[0041] As a possible implementation, the orthographic projection of the at least one second doped portion B on the first doped portion is located between two adjacent strip-shaped regions included in the first doped portion.

[0042] In the case of the above technical solution, the part of the first doped portion corresponding to the strip-shaped region is usually provided with the first current collecting electrode, and at least part of the region of the first current collecting electrode needs to be in electrical contact with the part of the first doped portion corresponding to the strip-shaped region to collect the carriers in the strip-shaped region. Moreover, the part of the first doped portion corresponding to the connecting region is usually provided with the first bus electrode to guide the carriers collected by the first current collecting electrode out, and the first bus electrode can not be in direct electrical contact with the part of the first doped portion corresponding to the connecting region. In the above case, when the orthographic projection of the at least one second doped portion B on the first doped portion is located between two adjacent strip-shaped regions included in the first doped portion, the second doped portion B and the first current collecting electrode are spaced apart under the premise of shortening the time for selectively processing the mask material, which is beneficial to prevent the first current collecting electrode from being short-circuited by being overlapped on the second doped portion B, and to ensure the back contact cell to have higher working reliability.

[0043] As a possible implementation, the at least part of the at least one second doped part B has a positive projection on the first doped part within the intersection region of the strip region and the connecting region included by the first doped part. In this case, another possible implementation is provided for the forming position of the second doped part B above the first doped part, which is conducive to improving the applicability of the back contact battery provided by the present application in different application scenarios.

[0044] As a possible implementation, along the length direction of the strip region, the ratio of the width of the at least one second doped part B to the length of the strip region included by the first doped part is greater than or equal to 0.02 and less than or equal to 0.7. In the above case, the ratio of the width of the at least one second doped part B to the length of the strip region included by the first doped part has a relatively large optional range, which facilitates reasonable setting of the width of the second doped part B according to the needs of different actual application scenarios, and is conducive to improving the applicability of the back contact battery provided by the present application in different application scenarios.

[0045] As a possible implementation, the above-mentioned back contact battery includes a first current collecting electrode and a first busbar. The first current collecting electrode is formed on a part of the corresponding strip region of the first doped part, and the first current collecting electrode is in electrical contact with the first doped part. The first busbar is formed above a part of the corresponding connecting region of the first doped part and the second doped part B, and is in electrical connection with a plurality of first current collecting electrodes. The first current collecting electrode and the first busbar are respectively insulated from the second doped part B.

[0046] As a possible implementation, along the width direction of the strip region, the ratio of the length of the at least one second doped part B to the distance between the adjacent two first current collecting electrodes is greater than or equal to 0.05 and less than or equal to 0.95.

[0047] In the case of adopting the above technical solution, the ratio of the length of the at least one second doped part B to the distance between the adjacent two first current collecting electrodes is within the above range, which is conducive to preventing the length of the second doped part B from being too small due to the small ratio, thereby reducing the degree of shortening of the selective processing time of the mask material, and ensuring the high manufacturing efficiency of the back contact battery. In addition, it is also conducive to preventing the distance between the second doped part B and the first current collecting electrode from being too small due to the large ratio, thereby preventing the formation of electric leakage between the second doped part B and the first current collecting electrode, ensuring that the back contact battery has high working performance, and at the same time, there is no need to strictly require the manufacturing precision of the first current collecting electrode in order to prevent the first current collecting electrode from overlapping the second doped part B, which is conducive to reducing the difficulty of manufacturing the first current collecting electrode.

[0048] As a possible implementation, along the width direction of the strip-shaped region, the interval between the at least one second doped part B and the two adjacent first collecting electrodes is greater than or equal to 5 mm and less than or equal to 30 mm. The beneficial effects in this case can refer to the beneficial effect analysis of the ratio of the length of the at least one second doped part B to the interval between the two adjacent first collecting electrodes being greater than or equal to 0.05 and less than or equal to 0.95 described above, which will not be repeated here.

[0049] As a possible implementation, along the length direction of the strip-shaped region, the ratio of the width of the at least one second doped part B to the width of the first busbar is greater than or equal to 0.1 and less than or equal to 5.

[0050] With the above technical solution, the ratio of the width of the at least one second doped part B to the width of the first busbar is within the above range, which is beneficial to prevent the transmission resistance of the first busbar from being high due to the width of the first busbar being small caused by the ratio being large, and is beneficial to reduce the transmission loss of the first busbar. In addition, it is also beneficial to prevent the width of the second doped part B from being small caused by the ratio being small, to ensure the high mass productivity of the back contact battery, and to prevent the width of the first busbar from being large caused by the ratio being small, to prevent the first busbar from being easily formed above the interval region and the first doped part, and to reduce the short circuit risk of the back contact battery.

[0051] As a possible implementation, the projected area of the at least one second doped part B on the first surface is S1, the projected area of the at least one first busbar on the first surface is S2, and 0.1S2≤S1≤0.9S2. In this case, the projected area S1 of the at least one second doped part B on the first surface has a relatively large selection range, and the formation range of the second doped part B on the first surface can be reasonably set according to the requirements of the manufacturing efficiency and the hot spot risk of the back contact battery in the actual application scenario, which is beneficial to improve the applicability of the back contact battery provided by the present application in different application scenarios.

[0052] As a possible implementation, the interconnection structure includes the first busbar.

[0053] In a second aspect, the present application provides a method for manufacturing a back contact cell, which comprises the following steps. First, a semiconductor substrate is provided. The semiconductor substrate has opposite first and second surfaces. The first surface has first and second regions arranged alternately. Next, a first doped portion is formed in the first region. Then, a second doped portion is formed on the first surface. The second doped portion includes a second doped portion A located in the second region and a second doped portion B located above a portion of the first doped portion away from the semiconductor substrate. The second doped portion and the first doped portion have opposite conductive types. The second doped portion B and the first doped portion are spaced apart along the thickness direction of the semiconductor substrate. Subsequently, a plurality of interconnection structures are formed on the side of the first doped portion away from the semiconductor substrate. The interconnection structures are electrically connected to the first doped portion. At least part of each second doped portion B is located between the first doped portion and the corresponding interconnection structure, and the second doped portion B and the interconnection structure are insulated from each other.

[0054] As a possible implementation, in the case where the material of the first doped portion includes silicon, the above-mentioned step of forming the first doped portion in the first region includes the following steps. First, a first doped semiconductor layer is formed on the side of the first surface. Next, an insulating mask layer is formed on the portion of the first doped semiconductor layer corresponding to the first region. Then, under the masking effect of the insulating mask layer, the portion of the first doped semiconductor layer located at least in the second region is removed. The remaining first doped semiconductor layer located on the first region forms the first doped portion. The portion of the insulating mask layer located between the first doped portion and the second doped portion B is a first insulating layer. The second doped portion B is spaced apart from the first doped portion by the first insulating layer.

[0055] As a possible implementation, the above-mentioned step of forming the second doped portion on the side of the first surface includes the following steps. First, a second doped semiconductor layer is formed to cover at least the first doped portion and the second region. Then, a mask material is formed on the side of the second doped semiconductor layer away from the semiconductor substrate. Next, the mask material is selectively processed so that the portion of the mask material not processed forms a mask layer. The mask layer is located above the portion of the second doped semiconductor layer corresponding at least to the second region and part of the first region. Then, the portion of the mask material subjected to selective processing is removed. Under the protection of the mask layer, the portion of the second doped semiconductor layer located above part of the first doped portion is selectively removed. The remaining second doped semiconductor layer located in the second region forms the second doped portion A, and the remaining second doped semiconductor layer located above at least the portion of the first doped portion away from the semiconductor substrate forms the second doped portion B.

[0056] As a possible implementation, after forming the second doped part on the first side, before forming the plurality of interconnection structures on the side of the first doped part away from the semiconductor substrate, the manufacturing method of the back contact cell further comprises: forming a surface passivation layer covering the side of the first doped part away from the semiconductor substrate and the side of the second doped part away from the semiconductor substrate, to obtain a second insulating layer. The interconnection structures are insulated from each other by the second insulating layer and the second doped part B.

[0057] As a possible implementation, the plurality of interconnection structures are formed on the side of the first doped part away from the semiconductor substrate by using a non-punch-through conductive paste.

[0058] The beneficial effects of the second aspect and various implementations thereof in the present application can be analyzed with reference to the beneficial effects of the first aspect and various implementations thereof, which will not be repeated here.

[0059] In a third aspect, the present application provides a photovoltaic module, which comprises: the back contact cell provided by the first aspect and various implementations thereof or the back contact cell formed by the manufacturing method of the back contact cell provided by the second aspect and various implementations thereof, and an intra-string interconnection for interconnecting adjacent back contact cells together.

[0060] The beneficial effects of the third aspect and various implementations thereof in the present application can be analyzed with reference to the beneficial effects of the first aspect and various implementations thereof, which will not be repeated here.

[0061] As a possible implementation, the ratio of the width of the at least one intra-string interconnection to the width of the second doped part B included in the corresponding back contact cell is greater than or equal to 0.5 and less than or equal to 2.

[0062] In the case of using the above technical solution, the ratio of the width of the at least one intra-string interconnection to the width of the second doped part B is within the above range, which is beneficial to prevent the ratio from being too large so that the width of the second doped part B is too small, to ensure the high mass productivity of the back contact cell, and is also beneficial to prevent the ratio from being too large so that the width of the intra-string interconnection is too large, which leads to the intra-string interconnection easily overlapping the second doped part A with opposite polarity to itself and / or other intra-string interconnections with opposite conductivity type to itself, to reduce the risk of short circuit. In addition, it is also beneficial to prevent the ratio from being too small, which is also beneficial to prevent the ratio from being too small so that the width of the intra-string interconnection is too small, which leads to the transmission resistance of the intra-string interconnection being too large, to ensure that the photovoltaic module has low transmission loss. BRIEF DESCRIPTION OF DRAWINGS

[0063] The accompanying drawings, which are included to provide a further understanding of the present application, form a part of the present application and illustrate the illustrative embodiments of the present application and its description, and do not constitute improper limitations on the present application. In the drawings:

[0064] FIG. 1 is a schematic diagram of a corresponding pattern of a laser engraving process in the related art;

[0065] FIG. 2 is a schematic diagram of a structure after forming a first doped portion and a second doped portion in the related art;

[0066] FIG. 3 is a schematic diagram of a structure after forming an electrode structure in the related art;

[0067] FIG. 4 is a schematic diagram of a longitudinal section of a structure of a back contact cell according to an embodiment of the present application;

[0068] FIG. 5 is a schematic diagram of a longitudinal section of a structure of a back contact cell according to an embodiment of the present application;

[0069] FIG. 6 is a schematic diagram of a distribution position of a first doped portion and a second doped portion in a back contact cell according to an embodiment of the present application;

[0070] FIG. 7 is a schematic diagram of a corresponding pattern of a selective process according to an embodiment of the present application;

[0071] FIG. 8 is a schematic diagram of a position relationship between a first region and a second region according to an embodiment of the present application;

[0072] FIG. 9 is a schematic diagram of another position relationship between a first region and a second region according to an embodiment of the present application;

[0073] FIG. 10 is a schematic diagram of a longitudinal section of a structure of a back contact cell according to an embodiment of the present application;

[0074] FIG. 11 is a schematic diagram of a longitudinal section of a structure of a back contact cell according to an embodiment of the present application;

[0075] FIG. 12 is a schematic diagram of a distribution position of a first doped portion and a second doped portion in a back contact cell according to an embodiment of the present application;

[0076] FIG. 13 is a schematic diagram of a structure after forming an electrode structure according to an embodiment of the present application;

[0077] FIG. 14 is a schematic diagram of a longitudinal section of a structure of a back contact cell according to an embodiment of the present application;

[0078] FIG. 15 is a schematic diagram of a longitudinal section of a structure of a back contact cell according to an embodiment of the present application;

[0079] FIG. 16 is a schematic diagram of a distribution position of a first doped portion and a second doped portion in a back contact cell according to an embodiment of the present application;

[0080] FIG. 17 is a schematic diagram of a structure after forming an electrode structure according to an embodiment of the present application;

[0081] FIG. 18 is a schematic diagram of a structure after forming an electrode structure according to an embodiment of the present application;

[0082] Figure 19 is a longitudinal sectional view of the structure of a back contact battery provided in an embodiment of this application;

[0083] Figure 20 is a longitudinal sectional view of the structure of a back contact battery provided in an embodiment of this application.

[0084] Figure 21 is a longitudinal sectional view of the structure of a back contact battery according to an embodiment of this application.

[0085] Figure 22 is a schematic diagram of the back contact battery provided in an embodiment of this application during the manufacturing process;

[0086] Figure 23 is a schematic diagram of the back contact battery provided in an embodiment of this application during the manufacturing process;

[0087] Figure 24 is a schematic diagram of the structure of a back contact battery provided in an embodiment of this application during the manufacturing process.

[0088] Figure 25 is a schematic diagram of the back contact battery provided in an embodiment of this application during the manufacturing process.

[0089] Figure 26 is a schematic diagram of the back contact battery provided in an embodiment of this application during the manufacturing process.

[0090] Figure 27 is a schematic diagram of the back contact battery provided in an embodiment of this application during the manufacturing process.

[0091] Figure 28 is a schematic diagram of the back contact battery provided in an embodiment of this application during the manufacturing process.

[0092] Figure 29 is a schematic diagram of the back contact battery provided in an embodiment of this application during the manufacturing process.

[0093] Figure 30 is a schematic diagram of the back contact battery provided in an embodiment of this application during the manufacturing process.

[0094] Figure 31 is a schematic diagram of the back contact battery provided in an embodiment of this application during the manufacturing process.

[0095] Reference numerals: 11 is the semiconductor substrate, 12 is the first region, 13 is the second region, 14 is the spacer region, 15 is the first doped region, 16 is the second doped region, 17 is the second doped region A, 18 is the second doped region B, 19 is the first collector electrode, 20 is the interconnect structure, 21 is the first insulating layer, 22 is the second insulating layer, 23 is the strip region, 24 is the connection region, 25 is the first bus electrode, 26 is the passivation layer, 27 is the interface passivation layer, 28 is the second collector electrode, 29 is the second bus electrode, 30 is the intrinsic semiconductor layer, 31 is the first doped semiconductor layer, 32 is the insulating mask layer, 33 is the second doped semiconductor layer, 34 is the mask material, and 35 is the mask layer. DETAILED DESCRIPTION

[0096] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It is to be understood, however, that the description is merely exemplary and is not intended to limit the scope of the present disclosure. Also, in the following description, descriptions of well-known structures and techniques are omitted to avoid obscuring the concept of the present disclosure.

[0097] In the drawings, various structural diagrams according to embodiments of the present disclosure are shown. These diagrams are not drawn to scale, in which certain details are exaggerated for clarity and others are omitted. The shapes and relative sizes of the various regions, layers, and elements shown in the drawings are exemplary only and can vary in actual implementation depending on manufacturing techniques and other factors. The shapes and relative sizes of the various regions, layers, and elements shown in the drawings are exemplary only and can vary in actual implementation depending on manufacturing techniques and other factors.

[0098] In the context of the present disclosure, when a layer or element is referred to as being "on" another layer or element, it can be directly on the other layer or element, or intervening layers or elements can be present therebetween. Also, if a layer or element is on another layer or element in one orientation, it can be under the other layer or element in an inverted orientation. In order to make the technical problems to be solved, technical solutions and beneficial effects of the present application clearer, further detailed description will be made to the present application in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are merely intended to explain the present application and not to limit the present application.

[0099] In addition, the terms "first", "second", etc. are used only for the purpose of description and should not be construed as indicating or implying relative importance or implying the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited. The meaning of "several" is one or more, unless otherwise explicitly and specifically limited.

[0100] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0101] A solar cell is a device that can convert the light energy of the sun into electrical energy. Among them, the solar cell with the positive electrode and the negative electrode on the back of the cell is a back contact cell. Compared with the double-sided contact solar cell, the front side of the back contact cell is not blocked by the metal electrode, so that the light-receiving side of the back contact cell has higher light utilization, and therefore the back contact cell has higher short-circuit current and photoelectric conversion efficiency. It is one of the technical directions to realize high-efficiency crystalline silicon cells at present.

[0102] As shown in FIG. 1, the back contact cell generally includes a semiconductor substrate, a first doped portion 15 and a second doped portion 16. The semiconductor substrate 11 has opposite first and second faces. The first doped portion 15 and the second doped portion 16 are alternately distributed on the first face side of the semiconductor substrate 11. And the conductive types of the first doped portion 15 and the second doped portion 16 are opposite to collect and lead out electrons and holes respectively, which is beneficial to form photoelectric current. However, the manufacturing efficiency of the existing back contact cell is low, which is not conducive to improving the production capacity of the back contact cell.

[0103] Specifically, in the actual manufacturing process, after forming the first doped portion on part of the first face of the semiconductor substrate, a doped semiconductor layer is formed on the first doped portion and the area of the first face exposed outside the first doped portion. Then, as shown in FIGS. 2 and 3, the part of the doped semiconductor layer on the first doped portion 15 is removed. In the existing manufacturing method, the above-mentioned selective etching is usually achieved by using a mask combined with a wet etching method, or by using a laser engraving combined with a wet etching method. The mask combined with the wet etching method is to print a mask glue on the area to be protected. When wet etching is performed, the area under the mask glue will be protected and retained, while the area without the mask glue will be etched by the chemical solution. The laser engraving combined with the wet etching method is to use a laser to engrave the doped silicon glass layer formed on the doped semiconductor layer according to the pattern. After wet etching, the area of the doped silicon glass layer etched by the laser will be etched by the chemical solution, while the area of the doped silicon glass layer not etched by the laser has high density and can protect the doped semiconductor layer below from the chemical solution, thereby forming the second doped portion 16.

[0104] Specifically, compared with the laser engraving combined with the wet etching method, the mask combined with the wet etching method has higher manufacturing efficiency, but the mask combined with the wet etching method is limited by the composition of the mask adhesive and the stability of screen printing and other factors, and there is no large-scale mass production at present. In the above laser engraving combined with the wet etching method, the laser engraving process benefits from the stability of the laser, making it a large-scale mass production solution. However, the laser used for the back contact battery is expensive, and the laser engraving pattern for manufacturing the back contact battery is relatively complex (the laser engraving pattern is the white area in FIG. 2), and the engraving time corresponding to a single cell is long, which leads to low manufacturing efficiency of the back contact battery and increased production cost, and is not conducive to improving the production capacity of the back contact battery.

[0105] To solve the above technical problems, in a first aspect, an embodiment of the present application provides a back contact battery. As shown in FIGS. 4 to 6, the back contact battery provided by an embodiment of the present application includes a semiconductor substrate 11, a first doped portion 15, a second doped portion 16, and a plurality of interconnection structures 20. The semiconductor substrate 11 has opposite first and second surfaces. The first surface has alternately distributed first and second regions 12 and 13. The first doped portion 15 is located in the first region 12. The second doped portion 16 includes a second doped portion A 17 located in the second region 13 and a second doped portion B 18 located above a portion of the first doped portion 15 away from the semiconductor substrate 11. The second doped portion 16 and the first doped portion 15 have opposite conductivity types. The second doped portion B 18 and the first doped portion 15 are spaced apart in the thickness direction of the semiconductor substrate 11. The plurality of interconnection structures 20 are located on the side of the first doped portion 15 away from the semiconductor substrate 11, and the interconnection structures 20 are electrically connected to the first doped portion 15, and the interconnection structures 20 cover part of the first doped portion 15. At least part of the area of each second doped portion B 18 is located between the corresponding interconnection structure 20 and the first doped portion 15, and the second doped portion B 18 and the interconnection structure 20 are insulated from each other.

[0106] In the working state of the back contact cell, the electron-hole pairs generated by the semiconductor substrate 11 after absorbing photons are separated by the first doped part 15 and the second doped part A 17, and one of the electrons and holes is collected by the first doped part 15 and is led out by the interconnection structure 20 electrically connected to the first doped part 15; the other of the electrons and holes is collected by the second doped part A 17 and is led out, forming a photoelectric current. In addition, the back contact cell provided by the embodiment of the present application includes, as shown in FIGS. 4 to 6, the second doped part 16, which not only includes the second doped part A 17 having the carrier separation and collection functions, but also includes the second doped part B 18 located above the portion of the first doped part 15 away from the semiconductor substrate 11. The second doped part B 18 and the first doped part 15 are spaced apart along the thickness direction of the semiconductor substrate 11, which is beneficial to preventing the leakage current between the second doped part B 18 and the first doped part 15 having the opposite conduction type. Moreover, at least part of each second doped part B 18 is located between the corresponding interconnection structure 20 and the first doped part 15 having the opposite conduction type, but the second doped part B 18 is insulated from the interconnection structure 20, so that the leakage current between the second doped part B 18 and the interconnection structure 20 can be prevented, and the back contact cell has higher working performance. Meanwhile, in the actual manufacturing process, the second doped part 16 is formed by selectively etching the second doped semiconductor layer 33 arranged on the first doped part 15 and the second region 13, as shown in FIGS. 6 and 7. Before the selective etching, the mask material formed on the side of the second doped semiconductor layer 33 away from the semiconductor substrate 11 needs to be selectively processed by laser engraving or the like, so that the part of the mask material not processed forms a mask layer for protecting the second doped part 16. It can be seen that the forming range of the second doped part 16 determines the range of the mask material to be processed. Based on this, when the second doped part 16 not only includes the second doped part A 17, but also includes the second doped part B 18 located above the portion of the first doped part 15 away from the semiconductor substrate 11, the part of the mask material corresponding to the second doped part B 18 does not need to be engraved (the pattern of the selective processing corresponds to the white area in FIG. 7), so that the processing time of the mask material can be shortened, the manufacturing efficiency of the back contact cell is improved, the production cost is reduced, and the manufacturing capacity of the back contact cell is increased.

[0107] In the actual application process, the material of the semiconductor substrate is not limited in the embodiment of the present application, and the semiconductor substrate can be a substrate of any one of semiconductor materials such as a silicon substrate, a germanium-silicon substrate, a germanium substrate, or a gallium arsenide substrate.

[0108] It can be understood that the first surface of the semiconductor substrate corresponds to the back surface of the back contact cell, and the second surface of the semiconductor substrate corresponds to the light surface of the back contact cell. In addition, the boundary between the first region 12 and the second region 13 of the first surface of the semiconductor substrate is a virtual boundary. As shown in FIGS. 4 and 5, the first doped part 15 is formed in the first region 12, and thus the range of the first region 12 on the first surface side can be determined according to the formation range requirement of the first doped part 15 in the actual application scenario. Secondly, the second doped part A17 is formed in the second region 13, and thus the range of the second region 13 on the first surface side can be determined according to the formation range requirement of the second doped part A17 in the actual application scenario, which is not specifically limited here. In addition, as shown in FIG. 4, the boundary of the first region 12 of the first surface of the semiconductor substrate 11 can coincide with the boundary of the second region 13; or, as shown in FIG. 5, the first region 12 and the second region 13 of the first surface of the semiconductor substrate 11 can also be alternately and spacedly distributed, that is, there is a spacing region 14 between the first region 12 and the adjacent second region 13. The existence of the spacing region 14 can separate at least part of the first doped part 15 and at least part of the second doped part A17 of the opposite conduction type, prevent a large leakage current between them, and cause the working efficiency of the back contact cell to be low, and ensure that the photovoltaic module including the back contact cell provided by the embodiment of the present application has a high photoelectric conversion efficiency in the forward voltage region. As for the width of the above-mentioned spacing region 14, it can be determined according to the anti-leakage requirement between the first doped part 15 and the second doped part A17 in the actual application scenario, which is not specifically limited here. In addition, in the actual application process, the above-mentioned spacing region can be formed with a groove, and at least part of the first doped part 15 located on the first region 12 and at least part of the second doped part A17 located on the second region 13 can be separated by the groove, and the depth of the groove is not specifically limited by the embodiment of the present application. Alternatively, the spacing region 14 can also be formed with an insulating part (the material of the insulating part can be an insulating material such as silicon oxide, silicon nitride, aluminum oxide, etc., and can also be an intrinsic semiconductor material, etc.), and at least part of the first doped part 15 and at least part of the second doped part A17 can be separated by the insulating part.

[0109] As for the appearance of the above-mentioned first region 12 and second region 13, it can be determined according to the type of the back contact cell, and the appearance of the first doped part 15 and the second doped part A17 included in the back contact cell, which is not specifically limited here.

[0110] For example, the first region 12 and the second region 13 can be alternately distributed in a strip shape, and at this time, the back contact cell provided by the embodiment of the present application can be a "no main grid back contact cell". As shown in FIG. 8, when the first region 12 and the second region 13 are spaced, the first region 12 and the second region 13 are alternately and spacedly distributed in a strip shape.

[0111] For example, the first region 12 and the second region 13 can be alternately arranged in an interdigital manner, and the back contact cell provided by the embodiment of the present application can be a "back contact cell with a main grid". As shown in FIG. 9, when the first region 12 and the second region 13 are arranged in an interdigital manner, the first region 12 and the second region 13 are alternately arranged in an interdigital manner.

[0112] For the first doped part 15, the embodiment of the present application does not make a specific limitation on the conductive type of the first doped part 15, as long as the conductive types of the first doped part 15 and the second doped part 16 are opposite. For example, the conductive type of the first doped part can be N type, and the conductive type of the second doped part can be P type; or the conductive type of the first doped part can be P type, and the conductive type of the second doped part can be N type.

[0113] From the forming position aspect, the first doped part 15 can be a doped region formed in the first region 12, as shown in FIG. 10; or the first doped part 15 can be a doped semiconductor layer formed on the first region 12, as shown in FIG. 4 and FIG. 5.

[0114] When the first doped part is a doped semiconductor layer formed on the first region, the material of the doped semiconductor layer can include any one of silicon, silicon-germanium, germanium, etc. In addition, when the first doped part 15 is a doped semiconductor layer formed on the first region 12, the first doped part 15 can be directly formed on the first region 12, as shown in FIG. 4 and FIG. 5; or the back contact cell can further include a passivation layer 26 between the semiconductor substrate 11 and the first doped part 15, as shown in FIG. 11. In this case, the passivation layer 26 and the first doped part 15 can constitute a selective contact structure to realize chemical passivation of the first region 12 on the first surface of the semiconductor substrate 11, selective collection of carriers of the corresponding conductive type, reduction of the carrier recombination rate on the first surface side, and improvement of the photoelectric conversion efficiency of the back contact cell.

[0115] The material of the passivation layer can be determined according to the material of the first doped part. For example, when the first doped part includes a doped crystalline silicon layer, the passivation layer is a tunneling passivation layer. For another example, when the first doped part includes a doped amorphous silicon layer, the passivation layer includes an intrinsic amorphous silicon layer. In addition, the embodiment of the present application does not make a specific limitation on the material of the passivation layer.

[0116] For the second doped portion, the material of the second doped portion can include any semiconductor material such as silicon, silicon-germanium, germanium, etc. The material of the second doped portion can be the same as or different from the material of the first doped portion. In addition, as shown in FIG. 10, the second doped portion 16 can be directly formed on the second region 13 and the portion of the first doped portion 15 facing away from the semiconductor substrate 11; or as shown in FIG. 11, the back contact cell can further include an interface passivation layer 27 located at least between the semiconductor substrate 11 and the second doped portion A 17 included in the second doped portion 16 and between the first doped portion 15 and the second doped portion B 18 included in the second doped portion 16. In this case, the interface passivation layer 27 and the second doped portion A 17 can constitute a selective contact structure to achieve chemical passivation of the second region 13 on the first surface of the semiconductor substrate 11 and selective collection of the carriers of the corresponding conductivity type, reduce the carrier recombination rate on the first surface side, and facilitate improvement of the photoelectric conversion efficiency of the back contact cell. In addition, the first doped portion 15 and the second doped portion B 18 can be spaced apart to inhibit leakage.

[0117] The material of the interface passivation layer can be determined according to the material of the second doped portion. For example, in the case where the second doped portion includes a doped crystalline silicon layer, the interface passivation layer is a tunneling passivation layer. For another example, in the case where the second doped portion includes a doped amorphous silicon layer, the interface passivation layer includes an intrinsic amorphous silicon layer. In addition, the material of the interface passivation layer is not limited in the embodiments of the present application.

[0118] In addition, the back contact cell includes a physical spacing layer located between the first doped portion and the second doped portion B included in the second doped portion. The second doped portion B and the first doped portion can be spaced apart by the physical spacing layer. The physical spacing layer can be a dielectric layer with a certain resistivity to hinder the formation of a leakage current between the second doped portion B and the first doped portion. For example, as shown in FIG. 10 and FIG. 11, the physical spacing layer can be a first insulating layer 21 located at least between the first doped portion and the second doped portion B. In this case, the first insulating layer 21 is a non-conductive film layer, so when the first insulating layer 21 is located at least between the first doped portion and the second doped portion B, the first doped portion can be insulated from the second doped portion B with the opposite conductivity type by the first insulating layer 21, to ensure that no leakage current is generated between them, and to ensure that the back contact cell has high working performance on the premise of improving the efficiency of selective processing of the mask material. The dielectric constant and the resistivity of the first insulating layer can be determined according to the actual application scenario, which is not limited here.

[0119] For example, the dielectric constant of the first insulating layer is greater than or equal to 4.5 and less than or equal to 6.5. In this case, it is beneficial to prevent the first insulating layer from having poor insulation performance due to a small dielectric constant of the first insulating layer, and to ensure that the first doped portion and the second doped portion B can be insulated from each other by the first insulating layer.

[0120] For example, the resistivity of the first insulating layer is greater than or equal to 5 x 10 9 Ω·cm and less than or equal to 5 x 10 12 Ω·cm. The beneficial effects in this case can be analyzed with reference to the beneficial effects of the dielectric constant of the first insulating layer being greater than or equal to 4.5 and less than or equal to 6.5, which are not repeated here.

[0121] The material of the first insulating layer can be determined according to the material of the first doped portion and the structure of the back contact cell, as long as the first doped portion and the second doped portion B can be electrically insulated by the first insulating layer.

[0122] For example, in the case where the material of the first doped portion includes silicon, the first insulating layer can include a doped silicon glass layer. In this case, when the material of the first doped portion includes silicon, a doped silicon glass layer can be formed on the side of the first doped portion away from the semiconductor substrate after diffusion treatment. Based on this, when the first insulating layer includes a doped silicon glass layer, at least part of the first insulating layer can be formed at the same time as the diffusion treatment, which is beneficial to improve the manufacturing efficiency of the first insulating layer and further improve the manufacturing capacity of the back contact cell while ensuring that the first doped portion and the second doped portion B can be prevented from generating leakage by the first insulating layer.

[0123] For example, in the case where the back contact cell further includes an interface passivation layer, the first insulating layer can include the interface passivation layer.

[0124] From the aspect of forming range, the second doped portion 16 includes a second doped portion A 17 formed in the second region of the first surface of the semiconductor substrate. As shown in FIGS. 10-13, the second doped portion 16 includes a second doped portion B 18 which can only be located above the portion of the first doped portion 15 facing away from the semiconductor substrate 11; or as shown in FIGS. 14-17, the second doped portion B 18 can be located above the portion of the first doped portion 15 facing away from the semiconductor substrate 11 and extend in a direction close to the second doped portion A 17, so as to increase the forming range of the second doped portion B 18 and further shorten the time for selectively processing the mask material, and facilitate electrical connection of the local region of the first doped portion 15 to the local region of the second doped portion A 17 with the opposite conduction type, so as to form a built-in diode with a lower reverse breakdown voltage by electrically connecting the first doped portion 15 and the second doped portion B 18 (or the second doped portion B 18 and the second doped portion A 17) through the manufacturing of a local leakage point, thereby facilitating a lower reverse breakdown voltage of the back contact cell when it is shielded.

[0125] As for the specific forming position of the second doped portion B on the side of the first doped portion facing away from the semiconductor substrate, it can be determined according to the topography of the actual first doped portion and the second doped portion A, and the forming position of the interconnection structure on the side of the first doped portion facing away from the semiconductor substrate, as long as at least part of the second doped portion B is located between the interconnection structure and the first doped portion, and the second doped portion B and the interconnection structure are insulated from each other.

[0126] In an example, in the case where the first doped portion and the second doped portion A are alternately and spacedly distributed in a strip shape, specifically, the first doped portion and the second doped portion A each include a plurality of strip regions, the strip regions included in the first doped portion and the strip regions included in the second doped portion A are parallel and spacedly distributed, and there is a spacing region between adjacent two strip regions. It should be noted that each strip region can be continuously extended or discontinuously extended; of course, it can also be that part of the strip regions are continuously extended and part of the strip regions are discontinuously extended, wherein as shown in FIG. 12, the orthographic projection of at least one second doped portion B 18 on the first surface can be located only in part of the orthographic projection of the strip region 23 included in the first doped portion 15 on the first surface; or as shown in FIGS. 14-16, the orthographic projection of at least one second doped portion B 18 on the first surface can be located in part of the orthographic projection of the strip region 23 included in the first doped portion 15 on the first surface and the second doped portion B 18 extends in the width direction of the strip region 23 to the spacing region 14.

[0127] In the above technical solution, as shown in FIG. 12 and FIG. 16, the forming range of the second doped portion B18 on the first side has at least the above two embodiments. As shown in FIG. 12, when the orthographic projection of at least one second doped portion B18 on the first side is located in the partial area of the orthographic projection of the strip-shaped region 23 included in the first doped portion 15 on the first side, the part of the first doped portion 15 located below the second doped portion B18 can be electrically isolated by the spacing region 14 and the second doped portion A17 opposite in conductive type, which is conducive to reducing the leakage current of the back contact cell. As shown in FIG. 14 to FIG. 16, when the orthographic projection of at least one second doped portion B18 on the first side is located in the partial area of the orthographic projection of the strip-shaped region 23 included in the first doped portion 15 on the first side, and the second doped portion B18 extends to the spacing region 14 along the width direction of the strip-shaped region 23, the forming range of the second doped portion B18 on the first side is relatively large, which can further shorten the processing time of the mask material, improve the manufacturing efficiency of the back contact cell, reduce the production cost, and increase the manufacturing capacity of the back contact cell. At the same time, compared with the orthographic projection of at least one second doped portion B18 on the first side being located in the partial area of the orthographic projection of the strip-shaped region 23 included in the first doped portion 15 on the first side, when the second doped portion B18 extends to the spacing region 14 along the width direction of the strip-shaped region 23, if the first doped portion 15 and the second doped portion B18 are both doped layers located on the semiconductor substrate, the second doped portion B18 can be overlapped with the sidewall of the first doped portion 15 in the thickness direction to form a conductive channel, which is conducive to forming a leakage current between the second doped portion B18 and the first doped portion 15, and the distance between the second doped portion B18 and the second doped portion A17 is small, which is conducive to electrically connecting the local area of the first doped portion 15 through the local area of the second doped portion B18 and the second doped portion A17 opposite in conductive type, so that the first doped portion 15 and the second doped portion B18 (or the second doped portion B18 and the second doped portion A17) are electrically connected to form a built-in diode with a lower reverse breakdown voltage, which is conducive to the back contact cell having a lower reverse breakdown voltage when it is shielded. The part of the first doped portion 15 not corresponding to the second doped portion B18 can be physically isolated by the spacing region 14 and other areas of the second doped portion A17, so as to prevent the leakage current between the two from being too large and causing the back contact cell to have a lower working efficiency, and to ensure that the photovoltaic module including the back contact cell provided in the embodiments has a higher photoelectric conversion efficiency in the forward voltage region. In the above case, the forming range of the second doped portion B18 on the first side has at least the above two embodiments, each of which has different advantages, so as to facilitate the selection of a suitable solution according to different application scenarios, and to improve the applicability of the back contact cell provided in the embodiments in different application scenarios.

[0128] In the case where the orthogonal projection of the at least one second doped region B18 on the first surface is located only in a partial region of the orthogonal projection of the strip-shaped region included by the first doped region 15 on the first surface, as shown in FIG. 12, the width and length of the second doped region B18 affect the forming range of the second doped region B18, and thus affect the time for selectively processing the mask material in the manufacturing process, and further affect the manufacturing efficiency of the back contact cell. In addition, the width and length of the second doped region B18 also affect the spacing between the second doped region B18 and the second doped region A17 along the width direction of the strip-shaped region, and thus affect the width of the mask material to be removed above the spacing, and further affect the accuracy requirement for selectively processing the mask material. In addition, along the length direction of the strip-shaped region, the first collecting electrode in electrical contact with the strip-shaped region is generally arranged above the region of the strip-shaped region included by the first doped region 15 except the region covered by the interconnection structure 20, for collecting and leading out the carriers. That is, the first collecting electrode is formed on the side of the first doped region away from the semiconductor substrate, and the first collecting electrode is in electrical contact with the first doped region; the extension direction of the first collecting electrode is the same as the extension direction of the spacing region, and the second doped region B18 is not arranged in the region between the first collecting electrode and the spacing region adjacent to the first collecting electrode except the region corresponding to the interconnection structure. Based on this, the length of the second doped region B18 affects the spacing between the second doped region B18 and the first collecting electrode with opposite conduction type, and further affects the anti-creeping effect between the second doped region B18 and the first collecting electrode. In the above case, the width and length of the second doped region B18 can be determined according to the requirements of the manufacturing efficiency of the back contact cell, the accuracy of selectively processing the mask material, and the anti-creeping effect between the second doped region B18 and the first collecting electrode, etc. in the actual application scenario.

[0129] For example, in the case where the orthogonal projection of the at least one second doped region B on the first surface is located only in a partial region of the orthogonal projection of the strip-shaped region included by the first doped region on the first surface, along the width direction of the strip-shaped region, the ratio of the width of the second doped region B to the width of the strip-shaped region included by the first doped region is greater than or equal to 0.1 and less than or equal to 1. For example, the ratio of the width of the second doped region B to the width of the strip-shaped region included by the first doped region can be 0.1, 0.2, 0.4, 0.6, 0.8 or 1, etc. In this case, along the width direction of the strip-shaped region, the ratio of the width of the second doped region B to the width of the strip-shaped region included by the first doped region is within the above range, which is beneficial to preventing the width of the second doped region B from being too small due to the small ratio, and thus preventing the time for selectively processing the mask material from being shortened to a low degree, and ensuring a high manufacturing efficiency of the back contact cell.

[0130] For example, in the case that the orthographic projection of the at least one second doped part B on the first face is located only in a partial area of the orthographic projection of the strip-shaped region included in the first doped part on the first face along the width direction of the strip-shaped region, the minimum distance between the orthographic projection edge of the at least one second doped part B on the first doped part and the edge of the corresponding strip-shaped region included in the first doped part is greater than or equal to 0 and less than or equal to 2 mm. For example, the minimum distance between the orthographic projection edge of the at least one second doped part B on the first doped part and the edge of the corresponding strip-shaped region included in the first doped part can be 0, 0.2 mm, 0.4 mm, 0.6 mm, 1 mm, 1.5 mm, 1.8 mm or 2 mm, etc. The beneficial effects in this case can refer to the beneficial effect analysis of the ratio of the width of the second doped part B to the width of the strip-shaped region included in the first doped part being greater than or equal to 0.1 and less than or equal to 1 described above, which will not be repeated here.

[0131] For example, along the length direction of the strip-shaped region, the ratio of the length of the second doped part B to the length of the interconnection structure can be greater than or equal to 0.1 and less than or equal to 0.9. For example, the ratio of the length of the second doped part B to the length of the interconnection structure can be 0.1, 0.2, 0.4, 0.6, 0.8 or 0.9. In this case, when the ratio of the length of the second doped part B to the length of the interconnection structure is within the above range, it is beneficial to prevent the time for selectively processing the mask material from being shortened to a lower degree due to the length of the second doped part B being too small caused by the ratio being too small, thereby ensuring a higher manufacturing efficiency of the back contact cell. In addition, it is also beneficial to prevent the distance between the second doped part B and the first collecting electrode of the opposite conduction type from being too small caused by the ratio being too large, thereby ensuring that no leakage current occurs between the second doped part B and the first collecting electrode, and ensuring that the back contact cell has a higher working efficiency.

[0132] In addition, when the second doped part B extends to the spacing region along the width direction of the strip-shaped region, as shown in FIGS. 14-16, the width of the part of the second doped part B 18 extending to the spacing region 14 can be smaller than the width of the spacing, at which time there is a gap between the second doped part B 18 and the adjacent second doped part A 17, which is beneficial to control the leakage current between the first doped part 15 and the second doped part 16, prevent the leakage current between them from being too large, and cause the working efficiency of the back contact cell to be too low, thereby ensuring that the photovoltaic module including the back contact cell provided in the embodiments of the present application has a higher photoelectric conversion efficiency in the forward voltage region.

[0133] Alternatively, as shown in FIG. 16, the width of the portion of the at least one second doped portion B18 extending to the spacing region 14 can be equal to the width of the spacing region 14, and the portion of the at least one second doped portion B18 extending to the spacing region 14 is in contact with the adjacent second doped portion A 17. In other words, the at least one second doped portion B18 is arranged continuously with the second doped portion A 17 and extends from above the first doped portion 15 to the spacing region 14, which is conducive to increasing the leakage current between the first doped portion 15 and the second doped portion 16, increasing the reverse breakdown voltage of the back contact cell, and improving the hot spot prevention effect of the photovoltaic module comprising the back contact cell provided in the embodiments of the present application. In the above case, the width of the portion of the second doped portion B18 extending to the spacing region 14 corresponds to different effects, and the width of the portion of the second doped portion B18 extending to the spacing region 14 can be reasonably set according to different application scenarios, which is not specifically limited here.

[0134] For example, the ratio of the width of the portion of the second doped portion B extending to the spacing region to the width of the spacing region can be greater than or equal to 0.1 and less than or equal to 1 along the width direction of the strip-shaped region. For example, the ratio of the width of the portion of the second doped portion B extending to the spacing region to the width of the spacing region can be 0.1, 0.2, 0.4, 0.6, 0.8 or 1, etc.

[0135] In another example, when the first doped portion and the second doped portion A are in the form of interdigitated alternating intervals, the first doped portion and the second doped portion A each include a plurality of strip regions and a plurality of connecting regions. The strip regions included by the first doped portion and the strip regions included by the second doped portion A are parallel and alternatingly spaced. The connecting regions included by the first doped portion intersect with the corresponding strip regions included by the first doped portion. The connecting regions included by the second doped portion A intersect with the corresponding strip regions included by the second doped portion A. The length direction of the connecting regions is different from the length direction of the strip regions. In this case, as shown in FIG. 13, the orthographic projection of at least one second doped portion B 18 on the first surface can be located only in part of the orthographic projection of the connecting regions included by the first doped portion 15 on the first surface; or, as shown in FIG. 17, the orthographic projection of at least one second doped portion B 18 on the first surface is located in part of the orthographic projection of the connecting regions included by the first doped portion 15 on the first surface, and the second doped portion B 18 extends to the interval region 14 along the length direction of the strip regions. The beneficial effects of this case can refer to the beneficial effect analysis of the case where, when the first doped portion and the second doped portion A are in the form of strip alternating intervals, the orthographic projection of at least one second doped portion B 18 on the first surface is located only in part of the orthographic projection of the strip regions included by the first doped portion on the first surface; or, the orthographic projection of at least one second doped portion B 18 on the first surface is located in part of the orthographic projection of the strip regions included by the first doped portion on the first surface, and the second doped portion B 18 extends to the interval region 14 along the width direction of the strip regions, which is not repeated here. The extension direction of the first current collecting electrode intersects with the extension direction of the interval region, and no second doped portion B is arranged between the end portion of the first current collecting electrode and the interval region.

[0136] In the length direction of the strip-shaped region, as shown in FIG. 13, in the case where the orthographic projection of the second doped part B18 on the first surface is located only in the partial region of the orthographic projection of the connecting region included in the first doped part on the first surface, the width and length of the second doped part B18 will affect the forming range of the second doped part B18, thereby affecting the time of the selective processing of the mask material in the manufacturing process, and further affecting the manufacturing efficiency of the back contact cell. Secondly, it will also affect the spacing between the second doped part B18 and the second doped part A17 in the length direction of the strip-shaped region, thereby affecting the width of the mask material to be removed above the spacing, and further affecting the accuracy requirement of the selective processing of the mask material. In addition, the part of the first doped part 15 corresponding to the strip-shaped region is usually provided with a first collecting electrode, the first collecting electrode is formed on the side of the first doped part 15 away from the semiconductor substrate, and at least part of the region of the first collecting electrode needs to be in electrical contact with the part of the first doped part 15 corresponding to the strip-shaped region, so as to collect the carriers in the strip-shaped region. And the part of the first doped part 15 corresponding to the connecting region is usually provided with a first bus electrode above, so as to guide the carriers collected by the first collecting electrode out, and the first bus electrode can not be in direct electrical contact with the part of the first doped part 15 corresponding to the connecting region. Based on this, the length of the second doped part B18 will affect the spacing between the second doped part B18 and the first collecting electrode with the opposite conduction type, and further affect the anti-creeping effect between the second doped part B18 and the first collecting electrode. In the above case, the width and length of the second doped part B18 can be determined according to the requirements of the manufacturing efficiency of the above back contact cell, the accuracy of the selective processing of the mask material, and the anti-creeping effect between the second doped part B18 and the first collecting electrode, etc. in the actual application scenario.

[0137] For example, in the case that the orthogonal projection of the second doped part B on the first surface is only located in the partial area of the orthogonal projection of the connecting area included in the first doped part on the first surface, the distance between the orthogonal projection edge of the second doped part B on the first doped part and the edge of the corresponding connecting area included in the first doped part can be greater than or equal to 0 and less than or equal to 2 mm along the length direction of the strip-shaped area. For example, the distance between the orthogonal projection edge of the second doped part B on the first doped part and the edge of the corresponding connecting area included in the first doped part can be 0, 0.2 mm, 0.4 mm, 0.6 mm, 1 mm, 1.5 mm, 1.8 mm or 2 mm, etc. In this case, the distance between the orthogonal projection edge of the second doped part B on the first doped part and the edge of the corresponding connecting area included in the first doped part is within the above range along the length direction of the strip-shaped area, which is beneficial to preventing the time for selectively processing the mask material from being shortened to a lower degree due to the smaller width of the second doped part B caused by the larger distance, and ensuring the higher manufacturing efficiency of the back contact battery. In addition, it is also beneficial to preventing the width of the mask material to be removed above the distance between the second doped part B and the second doped part A along the length direction of the strip-shaped area from being smaller due to the smaller distance, which is beneficial to reducing the precision requirement for selectively processing the mask material and reducing the difficulty of selectively processing the mask material.

[0138] For example, the ratio of the width of the at least one second doped part B to the length of the strip-shaped area included in the first doped part can be greater than or equal to 0.02 and less than or equal to 0.7 along the length direction of the strip-shaped area. For example, the ratio of the width of the at least one second doped part B to the length of the strip-shaped area included in the first doped part can be 0.02, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6 or 0.7, etc. In the above case, the ratio of the width of the at least one second doped part B to the length of the strip-shaped area included in the first doped part has a larger optional range, which is beneficial to reasonably setting the width of the second doped part B according to the needs of different actual application scenarios, and improving the applicability of the back contact battery provided by the embodiments of the present application in different application scenarios.

[0139] In addition, the forming position of the second doped part B on the connecting area can be determined according to the forming position of the interconnection structure on the side of the first doped part away from the semiconductor substrate along the width direction of the strip-shaped area, as long as at least part of the second doped part B is located between the interconnection structure and the first doped part, and the second doped part B and the interconnection structure are insulated from each other.

[0140] Exemplarily, as shown in FIG. 13, the orthographic projection of the at least one second doped portion B18 on the first doped portion can be located between two adjacent strip regions 23 included in the first doped portion 15. In this case, while shortening the time for selectively processing the mask material, the second doped portion B18 can be spaced apart from the first collecting electrode, preventing the first collecting electrode from being short-circuited by being overlapped on the second doped portion B18, and ensuring that the back contact battery has high working reliability.

[0141] Exemplarily, as shown in FIG. 18, the orthographic projection of at least part of the at least one second doped portion B18 on the first doped portion 15 can also be located in the intersection region of the strip region and the connecting region included in the first doped portion 15. In this case, another possible implementation scheme is provided for the formation position of the second doped portion B18 above the first doped portion 15, which facilitates the applicability of the back contact battery provided in the embodiments of the present application in different application scenarios.

[0142] Exemplarily, as shown in FIG. 18, the orthographic projection of the at least one second doped portion B18 on the first doped portion can be located between two adjacent strip regions included in the first doped portion and extend to the intersection region of the strip region and the connecting region included in the first doped portion along the length direction of the connecting region.

[0143] In actual application, as shown in FIGS. 17 to 21, the above-mentioned back contact battery includes the first collecting electrode 19 and the first bus electrode 25. The first collecting electrode 19 is formed on the part of the first doped portion 15 corresponding to the strip region 23, and the first collecting electrode 19 is in electrical contact with the first doped portion 15. The first bus electrode 25 is formed above the part of the first doped portion 15 and the second doped portion B18 corresponding to the connecting region 24, and is in electrical connection with the plurality of first collecting electrodes 19. The first collecting electrode 19 and the first bus electrode 25 are insulated from each other with respect to the second doped portion B18. In the above-mentioned case, the spacing between the second doped portion B18 and the first collecting electrode 19, and the relationship between the width of the second doped portion B18 and the width of the first bus electrode 25 can be determined without specific limitation according to the requirements for the selective processing time, the risk of hot spot prevention, and the manufacturing precision of the first collecting electrode 19 in the actual application scenario.

[0144] For example, the ratio of the length of the at least one second doped portion B to the interval between the two adjacent first collecting electrodes along the width direction of the strip-shaped region can be greater than or equal to 0.05 and less than or equal to 0.95. For example, the ratio of the length of the at least one second doped portion B to the interval between the two adjacent first collecting electrodes can be 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 0.95, etc. In this case, the ratio of the length of the at least one second doped portion B to the interval between the two adjacent first collecting electrodes is within the above range, which is beneficial to prevent the length of the second doped portion B from being too small due to the small ratio, so that the time for selectively processing the mask material is shortened to a low degree, thereby ensuring a high manufacturing efficiency of the back contact battery. In addition, it is also beneficial to prevent the interval between the second doped portion B and the first collecting electrode from being too small due to the large ratio, so that the second doped portion B and the first collecting electrode are prone to form a leakage therebetween, thereby ensuring that the back contact battery has a high working performance, and at the same time, the manufacturing precision of the first collecting electrode does not need to be strictly required in order to prevent the first collecting electrode from being overlapped with the second doped portion B, which is beneficial to reduce the difficulty of manufacturing the first collecting electrode.

[0145] For example, the interval between the at least one second doped portion B and the two adjacent first collecting electrodes along the width direction of the strip-shaped region can be greater than or equal to 5 nm and less than or equal to 30 nm. For example, the interval between the at least one second doped portion B and the two adjacent first collecting electrodes can be 5 nm, 8 nm, 10 nm, 15 nm, 20 nm, 25 nm or 30 nm, etc. The beneficial effects in this case can be analyzed with reference to the beneficial effects of the ratio of the length of the at least one second doped portion B to the interval between the two adjacent first collecting electrodes being greater than or equal to 0.05 and less than or equal to 0.95 described above, which will not be repeated here.

[0146] For example, the ratio of the width of the at least one second doped portion B to the width of the first bus electrode along the length direction of the strip-shaped region can be greater than or equal to 0.1 and less than or equal to 5. For example, the ratio of the width of the at least one second doped portion B to the width of the first bus electrode can be 0.1, 0.5, 1, 2, 3, 4 or 5, etc. In this case, the ratio of the width of the at least one second doped portion B to the width of the first bus electrode is within the above range, which is beneficial to prevent the width of the first bus electrode from being too small due to the large ratio, so that the transmission resistance of the first bus electrode is high, thereby reducing the transmission loss of the first bus electrode. In addition, it is also beneficial to prevent the width of the second doped portion B from being too small due to the small ratio, thereby ensuring a high mass productivity of the back contact battery, and at the same time, it is also beneficial to prevent the width of the first bus electrode from being too large due to the small ratio, so that the first bus electrode is prone to be formed above the interval region and the first doped portion, thereby reducing the short circuit risk of the back contact battery.

[0147] For example, the at least one second doped portion B has a projected area S1 on the first surface, and the at least one first bus electrode has a projected area S2 on the first surface, and 0.1S2≤S1≤0.9S2. For example, S1 can be equal to 0.1S2, 0.2S2, 0.3S2, 0.4S2, 0.5S2, 0.6S2, 0.7S2, 0.8S2, or 0.9S2, etc. In this case, the projected area S1 of the at least one second doped portion B on the first surface has a relatively large optional range, and the forming range of the second doped portion B on the first surface can be reasonably set according to the requirements of the manufacturing efficiency of the back contact battery and the risk of hot spot prevention in the actual application scenario, which is beneficial to improve the applicability of the back contact battery provided in the embodiments of the present application in different application scenarios.

[0148] In addition, as shown in FIGS. 14-17, in actual application, whether the first doped portion 15 and the second doped portion A 17 are alternately and spacedly distributed in a strip shape or in an interdigital shape, when the second doped portion B 18 extends to the spacing region 14 along the width direction of the strip-shaped region, the spacing region 14 between the adjacent two strip-shaped regions can be formed with a groove, and the first doped portion 15 and the second doped portion B 18 are overlapped in the groove to form a conductive channel; or the back contact battery can also include an insulating portion formed in the spacing region 14, and the part of the second doped portion B 18 corresponding to the spacing region 14 is located on one side of the insulating portion and is overlapped with the first doped portion 15 to form a conductive channel. Based on this, the local region of the first doped portion 15 and the second doped portion B 18 of the opposite conductive type can be electrically connected through the conductive channel, and the first doped portion 15 and the second doped portion B 18 (or the second doped portion B 18 and the second doped portion A 17) can be electrically connected by manufacturing a local leakage point to form a built-in diode with a lower reverse breakdown voltage, thereby facilitating the back contact battery to have a lower reverse breakdown voltage when it is blocked.

[0149] In the above, the width of the part of the second doped region B extending to the spacing region can be equal to the width of the spacing region, or can be less than the width of the spacing region. Specifically, when the width of the part of the second doped region B extending to the spacing region is less than the width of the spacing region, the first doped region and the second doped region B can be spaced apart by a trench or an insulating portion. For example, as shown in FIG. 14, a part of the insulating portion is formed in a local area of the spacing region 14, and is located between the second doped region B 18 and the first doped region 15. In this case, the second doped region B 18 extends to the spacing region 14, and has a gap between the adjacent second doped region A 17, which is conducive to controlling the leakage current between the first doped region 15 and the second doped region 16, preventing the leakage current between the first doped region 15 and the second doped region 16 from being too large, and thus preventing the working efficiency of the back contact cell from being too low, and ensuring that the photovoltaic module including the back contact cell provided in the embodiments of the present application has a high photoelectric conversion efficiency in the forward voltage region. Moreover, when the insulating portion includes a part of the surface passivation layer, forming the part of the insulating portion in the local area of the spacing region 14 can also passivate the local area of the spacing region 14, reduce the number of defects, and be conducive to improving the photoelectric conversion efficiency of the back contact cell.

[0150] When the width of the part of the second doped region B extending to the spacing region is equal to the width of the spacing region, the part of the second doped region B extending to the spacing region causes the trenches of the spacing region to be discontinuously distributed. In addition, as shown in FIG. 15, when the insulating portion is formed in the spacing region 14, the corresponding part of the insulating portion is only located above the part of the second doped region B 18 extending to the spacing region 14. At least one second doped region B 18 extends to the spacing region 14 from above the first doped region 15, and is continuously arranged with the second doped region A 17.

[0151] In addition, as shown in FIGS. 14 and 15, when the second doped region B 18 extends to the spacing region 14, the interface passivation layer 27 is arranged between the second doped region A 17 and the semiconductor substrate 11, and between the second doped region B 18 and the first doped region 15 and the semiconductor substrate 11, respectively; and the interface passivation layer 27 is integrally continuous corresponding to the first region 12 and the part of the spacing region 14. In this case, the presence of the interface passivation layer 27 is conducive to spacing apart the first doped region 15 and the second doped region B 18, which have opposite conductive types, and is conducive to preventing leakage. At the same time, the interface passivation layer 27 can also passivate at least part of the surface of the spacing region 14 and the surface of the second region 13, reduce the carrier recombination rate on the first side, and be conducive to improving the photoelectric conversion efficiency of the back contact cell.

[0152] In some cases, as shown in FIGS. 17 and 18, the back contact cell provided by the embodiments of the present application further comprises a second current collecting electrode 28 and a second busbar 29. The second current collecting electrode 28 is formed on a portion of the strip region corresponding to the second doped portion A17 and is in electrical contact with the second doped portion A17. The second busbar 29 is formed on a portion of the connecting region corresponding to the second doped portion A17 and is in electrical contact with the second current collecting electrode 28.

[0153] For the above-mentioned interconnection structure, the interconnection structure can be insulated from the second doped portion B by any non-conductive film layer. For example, as shown in FIGS. 19 to 21, the back contact cell further comprises a second insulating layer 22. The second insulating layer 22 covers the side of the first doped portion 15 away from the semiconductor substrate 11 and the side of the second doped portion 16 away from the semiconductor substrate 11. The interconnection structure 20 is insulated from the second doped portion B18 by the second insulating layer 22. In this case, the presence of the second insulating layer 22 can prevent the generation of leakage current between the second doped portion B18 and the interconnection structure 20, ensuring that the back contact cell has higher working performance. It should be noted that FIG. 19 is a longitudinal sectional view along the length direction of the strip region and at the second current collecting electrode. FIG. 20 is a longitudinal sectional view along the width direction of the strip region. FIG. 21 is a longitudinal sectional view along the length direction of the connecting region and at the first busbar.

[0154] Optionally, as shown in FIGS. 19 to 21, the second insulating layer 22 covers the side surface and the side of the second doped portion B18 away from the semiconductor substrate 11. In this case, the second insulating layer 22 can wrap the second doped portion B18, insulating the second doped portion B18 from other conductive structures such as the interconnection structure 20 having a conductive type opposite to that of the second doped portion B18 and located on the side or above the second doped portion B18, preventing the generation of leakage current.

[0155] Optionally, the second insulating layer is coated on the side surface and the side surface of the structure composed of the first doped part and the second doped part B away from the semiconductor substrate, and extends to the side surface and the side surface of the second doped part A away from the substrate. In this case, the second insulating layer can wrap the first doped part, the second doped part A and the second doped part B formed on the first side of the semiconductor substrate, prevent the problem of short circuit caused by the opposite doped parts after the interconnection structure and the electrode structure are formed, and at the same time, in the process of forming the photovoltaic module by interconnecting the back contact cells provided by the embodiment of the application, the second insulating layer can separate the corresponding doped parts in adjacent back contact cells, preventing short circuit caused by the contact between the opposite doped parts in the case of the adjacent back contact cells being close to or even contacting each other during the packaging extrusion process. Secondly, in the case where the second insulating layer includes a surface passivation layer, when the second insulating layer is coated on the side surface and the side surface of the structure composed of the first doped part and the second doped part B away from the semiconductor substrate, and extends to the side surface and the side surface of the second doped part A away from the substrate, the second insulating layer can simultaneously perform passivation treatment on the side surface and the side surface of the structure composed of the first doped part and the second doped part B away from the semiconductor substrate, and the side surface and the side surface of the second doped part A away from the substrate to which the second insulating layer extends, greatly reducing the surface defects on the back side of the back contact cell and reducing the carrier recombination rate.

[0156] In terms of materials, the material of the second insulating layer can be any insulating material such as silicon oxide, silicon nitride or aluminum oxide. Secondly, in an example, the second insulating layer can include a surface passivation layer. In this case, at least part of the second insulating layer can be formed at the same time as the surface passivation treatment is performed on the back side of the back contact cell, which not only ensures that the second doped part B and the interconnection structure can be prevented from generating leakage current by the second insulating layer, but also facilitates improving the manufacturing efficiency of the second insulating layer and further improving the manufacturing capacity of the back contact cell. The material and thickness of the surface passivation layer are not limited in the embodiment of the application.

[0157] In addition, in the case where the material of the second doped part includes silicon, the second insulating layer can further include a doped silicon glass layer formed on the side of the second doped part away from the semiconductor substrate after diffusion treatment.

[0158] In terms of structure, as shown in FIG. 19, the interconnection structure 20 can not extend to the second insulating layer 22. Alternatively, the interconnection structure 20 can also extend to a certain depth in the second insulating layer along the thickness direction of the semiconductor substrate 11. Based on this, since the thickness of the second insulating layer and the extension depth of the interconnection structure in the second insulating layer will affect the spacing between the interconnection structure and the second doped portion B, and further affect the insulation effect between the interconnection structure and the second doped portion B, the thickness of the second insulating layer and the extension depth of the interconnection structure in the second insulating layer can be determined according to the insulation effect requirement between the interconnection structure and the second doped portion B in the actual application scenario, and the characteristics of the conductive paste for manufacturing the interconnection structure, and the like, which is not specifically limited here.

[0159] For example, the ratio of the depth to which the interconnection structure extends in the second insulating layer to the thickness of the second insulating layer can be 0, 0.1, 0.3, 0.5, 0.6, 0.8, or 0.85, etc. In this case, since the second insulating layer has a certain thickness, and in the case that the minimum spacing between the side of the interconnection structure close to the semiconductor substrate and the second doped portion B opposite to the conductive type of the interconnection structure is greater than the anti-leakage spacing, the leakage current between the second doped portion B and the interconnection structure can be prevented. Based on this, when the ratio of the depth to which the interconnection structure extends in the second insulating layer to the thickness of the second insulating layer is greater than or equal to 0 and less than or equal to 0.85, the precision of the process parameters and the composition of the conductive paste for manufacturing the interconnection structure can be reduced under the premise of ensuring that no leakage current occurs between the second doped portion B and the interconnection structure, and the manufacturing difficulty of the interconnection structure is reduced.

[0160] For example, the thickness of the second insulating layer can be 60 nm, 80 nm, 100 nm, 120 nm, 140 nm, or 150 nm, etc. In this case, the thickness of the second insulating layer is within the above range, which is beneficial to prevent the minimum spacing between the side of the interconnection structure close to the semiconductor substrate and the second doped portion B opposite to the conductive type of the interconnection structure from being small due to the small thickness of the second insulating layer after the interconnection structure is formed, and to ensure that no leakage current occurs between the second doped portion B and the interconnection structure. In addition, it can also prevent the use amount of consumables for manufacturing the second insulating layer from being large due to the large thickness of the second insulating layer, which is beneficial to control the manufacturing cost of the back contact battery.

[0161] Exemplarily, the minimum distance between the side of the interconnection structure close to the semiconductor substrate and the second doped portion B can be greater than or equal to 15 nm and less than or equal to 60 nm along the thickness direction of the semiconductor substrate. For example, the minimum distance between the side of the interconnection structure close to the semiconductor substrate and the second doped portion B can be 15 nm, 20 nm, 30 nm, 40 nm, 50 nm or 60 nm, etc. In this case, the minimum distance between the side of the interconnection structure close to the semiconductor substrate and the second doped portion B is within the above range, which is beneficial to prevent the effect of preventing leakage current between the second doped portion B and the interconnection structure from being poor due to the small minimum distance, and ensure that the back contact cell has high working performance. In addition, under the condition that other factors are the same, it is also beneficial to prevent the use of a large amount of materials for manufacturing the second insulating layer due to the large minimum distance, which leads to the need to form a second insulating layer with a large thickness, and it is beneficial to control the manufacturing cost of the back contact cell.

[0162] Exemplarily, the second insulating layer can include an aluminum oxide passivation layer and a silicon nitride anti-reflection layer which are sequentially stacked in the direction away from the semiconductor substrate. In this case, the side of the interconnection structure close to the semiconductor substrate is located in the silicon nitride anti-reflection layer. In this case, the interconnection structure can be at least insulated from the second doped portion B with the opposite conduction type through the aluminum oxide passivation layer and the silicon nitride anti-reflection layer, to prevent the generation of leakage current. Specifically, the thickness of the aluminum oxide passivation layer and the silicon nitride anti-reflection layer, and the extension depth of the interconnection structure in the silicon nitride anti-reflection layer are not limited in the embodiments of the present application.

[0163] In actual application, the object to which the interconnection structure specifically refers can be determined according to the type of the back contact cell in the actual application scenario and the actual demand, which is not limited here.

[0164] For example, in the case of the back contact cell being a "main grid-free back contact cell", the interconnection structure can be an interconnection portion provided on the first current collecting electrode, or a part of the first current collecting electrode for electrically connecting with the interconnection portion. The size of the interconnection portion can be greater than or equal to the size of the first current collecting electrode. In the case where the size of the interconnection portion is equal to the size of the current collecting electrode, a non-welding process can be used to realize the interconnection of the back contact cell, such as a film coating process, in which a carrier film with an attached conductive interconnection member is directly attached to the surface of the back contact cell and is pressed to form an electrical interconnection.

[0165] For another example, in the case of the back contact cell being a "main grid back contact cell", the interconnection structure can be a first bus electrode, or an interconnection portion provided on the first bus electrode, or the interconnection structure can include the first bus electrode and the interconnection portion provided on the first bus electrode.

[0166] In a second aspect, the embodiments of the present application provide a manufacturing method of the back contact cell. The manufacturing process will be described below according to the cross-sectional views of the operations shown in FIGS. 22-31. Specifically, the manufacturing method of the back contact cell includes the following steps:

[0167] First, a semiconductor substrate is provided. The semiconductor substrate has opposite first and second surfaces. The first surface has first and second regions alternatingly distributed. The material of the semiconductor substrate, the first and second regions, and the range of the first surface, etc. can be referred to the foregoing and will not be repeated here.

[0168] Next, as shown in FIG. 26, the first doped portion 15 is formed in the first region 12. The material and conductive type of the first doped portion 15 can be referred to the foregoing and will not be repeated here. The specific formation process of the first doped portion 15 can be determined according to the positional relationship of the first doped portion 15 relative to the first region 12 and the material of the first doped portion 15, which will not be specifically limited here.

[0169] For example, in the case where the material of the first doped portion includes silicon, the above-mentioned forming the first doped portion in the first region can include the following steps: as shown in FIG. 23, a first doped semiconductor layer 31 is formed on the first surface side in an integral layer. Next, as shown in FIG. 25, an insulating mask layer 32 is formed on the portion of the first doped semiconductor layer 31 corresponding to the first region 12. Next, as shown in FIG. 26, under the masking effect of the insulating mask layer 32, the portion of the first doped semiconductor layer 31 at least on the second region 13 is removed. The remaining first doped semiconductor layer 31 on the first region 12 forms the first doped portion 15, and the portion of the insulating mask layer 32 between the second doped portion B18 and the first doped portion 15 forms the first insulating layer 21. The second doped portion B18 is spaced apart from the first doped portion 15 by the first insulating layer 21.

[0170] Specifically, the material of the first doped portion can refer to that the material of the first doped portion only includes silicon; or can also refer to that the material of the first doped portion includes silicon and other semiconductor materials such as germanium silicon. Secondly, in the actual manufacturing process, as shown in FIG. 22, a chemical vapor deposition process or the like can be used to form the intrinsic semiconductor layer 30. Next, as shown in FIG. 23, the intrinsic semiconductor layer is subjected to a diffusion treatment. After the diffusion treatment, not only the first doped semiconductor layer 31 for manufacturing the first doped portion 15 can be obtained, but also the insulating mask layer 32 with a material of doped silicon glass can be formed on the side of the first doped semiconductor layer 31 away from the semiconductor substrate. Then, as shown in FIGS. 24 and 25, the insulating mask layer 32 can be selectively removed at least on the second region 13 by using laser engraving combined with wet etching or the like. Next, as shown in FIG. 26, under the protection of the remaining part of the insulating mask layer 32, the first doped semiconductor layer can be selectively removed at least on the second region 13 by using a wet etching process or the like. After the selective removal, the remaining first doped semiconductor layer on the first region forms the first doped portion, and the part of the insulating mask layer between the first doped portion and the subsequently formed second doped portion B forms the first insulating layer. The second doped portion B is spaced apart from the first doped portion by the first insulating layer. Therefore, when the first insulating layer includes a doped silicon glass layer, at least part of the first insulating layer can be formed at the same time as the diffusion treatment is performed, which not only ensures that the first doped portion and the second doped portion B can be prevented from generating leakage current by the first insulating layer, but also facilitates improving the manufacturing efficiency of the first insulating layer and further improving the manufacturing capacity of the back contact cell.

[0171] It should be noted that when the manufactured back contact cell further includes a passivation layer between the first region and the first doped portion, after providing the semiconductor substrate and before forming the first doped portion on the first region, the manufacturing method of the back contact cell further includes the step of: using deposition and etching processes to first form the passivation layer on the first region.

[0172] Alternatively, as shown in FIG. 22, after providing the semiconductor substrate 11, a passivation layer 26 can be formed on the side of the first surface by using a chemical vapor deposition process or the like. Then, as shown in FIGS. 25 and 26, after the first doped semiconductor layer 31 is selectively etched, the passivation layer 26 is selectively etched. In this case, there is no need to form a corresponding mask layer for forming the passivation layer 26, which simplifies the manufacturing process of the back contact cell.

[0173] Next, as shown in Fig. 29, a second doped portion 16 is formed on the first surface. The second doped portion 16 includes a second doped portion A 17 on the second region 13, and a second doped portion B 18 on at least a portion of the first doped portion 15 facing away from the semiconductor substrate 11. The second doped portion 16 and the first doped portion 15 are of opposite conductivity types. The second doped portion B 18 and the first doped portion 15 are spaced apart in the thickness direction of the semiconductor substrate 11.

[0174] The material and the conductivity type of the second doped portion, and the formation range of the second doped portion B included in the second doped portion can be referred to the foregoing, and will not be described here again.

[0175] For example, the formation of the second doped portion on the first surface side can include the following steps. As shown in Fig. 27, a second doped semiconductor layer 33 is formed on at least the first doped portion 15 and the second region 13, and a mask material 34 is formed on the side of the second doped semiconductor layer 33 facing away from the semiconductor substrate 11. Next, the mask material is selectively processed so that the portion of the mask material not processed forms a mask layer 35 on at least the second doped semiconductor layer 33 corresponding to the second region 13 and a portion of the first region 12. Next, as shown in Fig. 28, the selectively processed portion of the mask material is removed. As shown in Fig. 29, under the protection of the mask layer 35, the second doped semiconductor layer on at least a portion of the first doped portion 15 is selectively removed, so that the remaining second doped semiconductor layer on the second region 13 forms the second doped portion A 17, and the remaining second doped semiconductor layer on at least a portion of the first doped portion 15 facing away from the semiconductor substrate 11 forms the second doped portion B 18.

[0176] In actual manufacturing process, the intrinsic semiconductor layer can be formed by chemical vapor deposition or other process, covering at least above the first doped part and the second region, and used for manufacturing the second doped part. Then, the intrinsic semiconductor layer can be doped by diffusion or other process, so as to form the second doped semiconductor layer. Next, the mask material can be formed on the side of the second doped semiconductor layer away from the semiconductor substrate by photolithography or deposition combined with selective etching. For example, in the case that the material of the second doped part includes silicon, after the diffusion process of the intrinsic semiconductor layer, a doped silicon glass layer is formed on the side of the second doped semiconductor layer away from the semiconductor substrate, and the mask material can be the doped silicon glass layer. Next, the mask material can be selectively processed by laser engraving or other process, so as to form the mask layer from the unprocessed part of the mask material. It can be understood that the larger the range of the selective processing of the mask material is, the longer the time of the selective processing is. Next, the part of the mask material subjected to the selective processing can be removed by wet etching or other process; and under the protection of the mask layer, the part of the second doped semiconductor layer above the part of the first doped part is selectively removed, so as to obtain the second doped part.

[0177] It should be noted that when the back contact cell to be manufactured further includes the interface passivation layer, after the first doped part is formed and before the second doped part is formed, the manufacturing method of the back contact cell further includes the step of: forming the interface passivation layer on the second region and the part of the first doped part by deposition and etching process.

[0178] Alternatively, as shown in FIG. 27, the interface passivation layer 27 can be formed on the first doped part 15 and the second region 13 by chemical vapor deposition or other process after the first doped part 15 is formed. Then, as shown in FIG. 28 and FIG. 29, the interface passivation layer 27 is selectively etched after the second doped semiconductor layer is selectively etched. In this case, the corresponding mask layer does not need to be formed additionally for forming the interface passivation layer 27, which simplifies the manufacturing process of the back contact cell.

[0179] In addition, as shown in FIG. 29, in actual manufacturing process, the removal of the mask layer also affects the previously described insulating mask layer, so that the part of the insulating mask layer exposed outside the second doped part B is removed, and the remaining part of the insulating mask layer is located only between the first doped part 15 and the second doped part B 18.

[0180] Exemplarily, after forming the second doped portion on the first side, and before forming the plurality of interconnection structures on the side of the first doped portion away from the semiconductor substrate, the method for manufacturing the back contact cell can further include the step of: forming a surface passivation layer covering the side of the first doped portion 15 away from the semiconductor substrate 11 and the side of the second doped portion 16 away from the semiconductor substrate 11, to obtain a second insulating layer 22, as shown in FIG. 30. The interconnection structures 20 are insulated from each other by the second insulating layer 22 and the second doped portion B 18. In this case, at least part of the second insulating layer 22 can be formed at the same time as the surface passivation treatment on the back light side of the back contact cell, which helps to improve the manufacturing efficiency of the second insulating layer 22 and further improve the manufacturing capacity of the back contact cell, while ensuring that the second doped portion B 18 and the interconnection structures 20 can be prevented from generating a leakage current by the second insulating layer 22. The specific structure and material of the second insulating layer 22 can be referred to the foregoing, and will not be described here again.

[0181] Next, as shown in FIG. 31, a plurality of interconnection structures 20 can be formed on the side of the first doped portion 15 away from the semiconductor substrate 11 by using a process such as screen printing or physical vapor deposition. The interconnection structures 20 are electrically connected to the first doped portion 15. At least part of each second doped portion B 18 is located between the corresponding interconnection structure 20 and the first doped portion, and the second doped portion B 18 is insulated from the interconnection structure 20. The specific object referred to by the interconnection structure 20 can be referred to the foregoing, and will not be described here again.

[0182] Exemplarily, a non-burn-through conductive paste can be used to form the plurality of interconnection structures on the side of the first doped portion away from the semiconductor substrate, which further ensures that no leakage current will occur between the interconnection structures and the second doped portion B, so that the back contact cell has higher structural reliability.

[0183] The beneficial effects of the second aspect and various implementation manners thereof in the embodiments of the present application can be analyzed with reference to the beneficial effects of the first aspect and various implementation manners thereof, and will not be described here again.

[0184] In a third aspect, the embodiments of the present application provide a photovoltaic module, which includes: the back contact cell provided by the first aspect and various implementation manners thereof or the back contact cell formed by using the manufacturing method of the back contact cell provided by the second aspect and various implementation manners thereof, and an intra-string interconnection for interconnecting adjacent back contact cells together.

[0185] The beneficial effects of the third aspect and various implementation manners thereof in the embodiments of the present application can be analyzed with reference to the beneficial effects of the first aspect and various implementation manners thereof, and will not be described here again.

[0186] For example, the ratio of the width of the at least one intra-string interconnect to the width of the second doped portion B included in the corresponding back contact cell is greater than or equal to 0.5 and less than or equal to 2.

[0187] In the above technical solution, the ratio of the width of the at least one intra-string interconnect to the width of the second doped portion B is within the above range, which is conducive to preventing the ratio from being too large so that the width of the second doped portion B is also too small, thereby ensuring a higher production yield of the back contact cell, while also being conducive to preventing the ratio from being too large so that the width of the intra-string interconnect is also too large, thereby causing the intra-string interconnect to easily overlap the second doped portion A having an opposite polarity to itself and / or other intra-string interconnects having an opposite conductivity type to itself, thereby reducing the risk of short circuit. In addition, it is also conducive to preventing the ratio from being too small, which is conducive to preventing the width of the intra-string interconnect from being too small, thereby causing the transmission resistance of the intra-string interconnect to be too large, thereby ensuring that the photovoltaic module has a lower transmission loss.

[0188] In the above description, the patterning, etching, and other technical details of each layer are not described in detail. However, those skilled in the art should understand that the layers, regions, and the like having the desired shape can be formed by various technical means. In addition, those skilled in the art can also design methods that are not exactly the same as the methods described above in order to form the same structure. In addition, although each embodiment is described above separately, this does not mean that the measures in each embodiment cannot be advantageously combined.

[0189] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes, and are not intended to limit the scope of the present disclosure. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A back contact cell, characterized in that, The back contact cell comprises: a semiconductor substrate having opposite first and second surfaces; the first surface has first and second regions arranged alternately; a first doped portion located in the first region; a second doped portion, which comprises a second doped portion A located in the second region and a second doped portion B located above a portion of the first doped portion away from the semiconductor substrate; the second doped portion and the first doped portion have opposite conductive types; the second doped portion B and the first doped portion are spaced apart in the thickness direction of the semiconductor substrate; a plurality of interconnection structures located on the side of the first doped portion away from the semiconductor substrate, and the interconnection structures are electrically connected to the first doped portion; at least part of each second doped portion B is located between the first doped portion and the corresponding interconnection structure, and the second doped portion B and the interconnection structure are insulated from each other.

2. The back contact cell of claim 1, wherein, The back contact cell further comprises a first insulating layer; the first insulating layer is located at least between the first doped portion and the second doped portion B; and / or, The back contact cell further comprises a second insulating layer; the second insulating layer covers the side of the first doped portion away from the semiconductor substrate and the side of the second doped portion away from the semiconductor substrate; the interconnection structures are insulated from each other by the second insulating layer and the second doped portion B.

3. The back contact cell of claim 2, wherein, In the case where the material of the first doped portion comprises silicon, the first insulating layer comprises a doped silicon glass layer; and / or, a dielectric constant of the first insulating layer is greater than or equal to 4.5 and less than or equal to 6.5; and / or, a resistivity of the first insulating layer is greater than or equal to 5 x 10 9 Ω·cm and less than or equal to 5 x 10 12 Ω·cm; and / or, The second insulating layer comprises a surface passivation layer.

4. The back contact cell of claim 2, wherein, The ratio of the depth to which the interconnection structure extends into the second insulating layer to the thickness of the second insulating layer is greater than or equal to 0 and less than or equal to 0.85; and / or, The thickness of the second insulating layer is greater than or equal to 60 nm and less than or equal to 150 nm; and / or, In the thickness direction of the semiconductor substrate, the minimum distance between the side of the interconnection structure close to the semiconductor substrate and the second doped portion B is greater than or equal to 15 nm and less than or equal to 60 nm; and / or, The second insulating layer comprises an aluminum oxide passivation layer and a silicon nitride anti-reflection layer stacked in sequence in the direction away from the semiconductor substrate; the side of the interconnection structure close to the semiconductor substrate is located in the silicon nitride anti-reflection layer; and / or, The second insulating layer covers the surface and side of the second doped portion B away from the semiconductor substrate; and / or, The second insulating layer covers the surface and side of the structure composed of the first doped portion and the second doped portion B away from the semiconductor substrate, and extends to the surface and side of the second doped portion A away from the substrate.

5. The back contact cell of claim 1, wherein, In the case where the first doped portion and the second doped portion A are alternately and spaced apart in the form of strips, the first doped portion and the second doped portion A each comprise a plurality of strip regions; the strip regions comprised by the first doped portion and the strip regions comprised by the second doped portion A are spaced apart and do not intersect, and have a spacing region between adjacent two strip regions; wherein, The projection of the at least one second doped portion B on the first surface is located only in a partial area of the projection of the strip-shaped region included in the first doped portion on the first surface; or, the projection of the at least one second doped portion B on the first surface is located in a partial area of the projection of the strip-shaped region included in the first doped portion on the first surface, and the second doped portion B extends to the spacing region along the width direction of the strip-shaped region.

6. The back contact cell of claim 5, wherein, In the case where the projection of the at least one second doped portion B on the first surface is located only in a partial area of the projection of the strip-shaped region included in the first doped portion on the first surface, The ratio of the width of the second doped portion B to the width of the strip-shaped region included in the first doped portion is greater than or equal to 0.1 and less than or equal to 1 along the width direction of the strip-shaped region; and / or, The minimum distance between the projection edge of the at least one second doped portion B on the first doped portion and the edge of the strip-shaped region included in the corresponding first doped portion is greater than or equal to 0 and less than or equal to 2 mm along the width direction of the strip-shaped region.

7. The back contact cell of claim 5, wherein, The ratio of the length of the second doped portion B to the length of the interconnection structure is greater than or equal to 0.1 and less than or equal to 0.9 along the length direction of the strip-shaped region; and / or, The ratio of the width of the part of the second doped portion B extending to the spacing region to the width of the spacing region is greater than or equal to 0.1 and less than or equal to 1 along the width direction of the strip-shaped region.

8. The back contact cell of claim 1, wherein, In the case where the first doped portion and the second doped portion A are alternately and spacedly distributed in an interdigital manner, the first doped portion and the second doped portion A each include a plurality of strip-shaped regions and a plurality of connection regions; the strip-shaped regions included in the first doped portion and the strip-shaped regions included in the second doped portion A are parallel and alternately spaced; the connection regions included in the first doped portion intersect with the corresponding strip-shaped regions included in the first doped portion; the connection regions included in the second doped portion A intersect with the corresponding strip-shaped regions included in the second doped portion A; the length direction of the connection regions is different from the length direction of the strip-shaped regions; wherein, The projection of the at least one second doped portion B on the first surface is located only in a partial area of the projection of the connection region included in the first doped portion on the first surface; or, the projection of the at least one second doped portion B on the first surface is located in a partial area of the projection of the connection region included in the first doped portion on the first surface, and the second doped portion B extends to the spacing region along the length direction of the strip-shaped region.

9. The back contact cell according to claim 5 or 8, characterized in that, The spacing region located between the adjacent two strip-shaped regions is formed with a groove, and the first doped portion and the second doped portion B overlap in the groove to form a conductive channel; Or, The back contact cell includes an insulating portion formed in the spacing region; the part of the second doped portion B corresponding to the spacing region is located on one side of the insulating portion and overlaps with the first doped portion to form a conductive channel.

10. The back contact cell of claim 9, wherein, Part of the insulating portion is formed in a local area of the spacing region and is located between the second doped portion B and the second doped portion A.

11. The back contact cell of claim 9, wherein, The first doped part and the second doped part B are both doped layers on the semiconductor substrate, and the second doped part B and the sidewall of the first doped part along the thickness direction are overlapped to form a conductive channel.

12. The back contact cell of claim 5 or 8, wherein, The back contact cell comprises an interface passivation layer; the interface passivation layer is arranged between the second doped part A and the semiconductor substrate, between the second doped part B and the first doped part, and between the second doped part B and the semiconductor substrate; The interface passivation layer is integrally continuous with the part corresponding to the first region and the interval region.

13. The back contact cell of claim 5 or 8, wherein, At least one second doped part B extends from above the first doped part to the interval region and is arranged continuously with the second doped part A.

14. The back contact cell of claim 8, wherein, In the case where the orthographic projection of the second doped part B on the first face is located only in the part of the orthographic projection of the connecting region included in the first doped part on the first face, the distance between the orthographic projection edge of the second doped part B on the first doped part and the edge of the connecting region included in the first doped part is greater than or equal to 0 and less than or equal to 2 mm along the length direction of the strip region.

15. The back contact cell of claim 8, wherein, At least one second doped part B is located between two adjacent strip regions included in the first doped part in the orthographic projection on the first doped part; and / or, At least part of the orthographic projection of at least one second doped part B on the first doped part is located in the intersection region of the strip region and the connecting region included in the first doped part.

16. The back contact cell of claim 8, wherein, The ratio of the width of at least one second doped part B to the length of the strip region included in the first doped part is greater than or equal to 0.02 and less than or equal to 0.7 along the length direction of the strip region.

17. The back contact cell of claim 8, wherein, The back contact cell comprises a first collecting electrode and a first busbar; the first collecting electrode is formed on the part of the first doped part corresponding to the strip region, and the first collecting electrode is in electrical contact with the first doped part; the first busbar is formed above the part of the first doped part and the second doped part B corresponding to the connecting region, and is in electrical connection with a plurality of first collecting electrodes; the first collecting electrode and the first busbar are respectively insulated from the second doped part B.

18. The back contact cell of claim 17, wherein, The ratio of the length of at least one second doped part B to the distance between two adjacent first collecting electrodes is greater than or equal to 0.05 and less than or equal to 0.95 along the width direction of the strip region; and / or, The distance between at least one second doped part B and two adjacent first collecting electrodes is greater than or equal to 5 mm and less than or equal to 30 mm along the width direction of the strip region; and / or, The ratio of the width of at least one second doped part B to the width of the first busbar is greater than or equal to 0.1 and less than or equal to 5 along the length direction of the strip region; and / or, The orthographic projection area of at least one second doped part B on the first face is S1, the orthographic projection area of at least one first busbar on the first face is S2, and 0.1S2≤S1≤0.9S2.

19. The back contact cell of claim 17, wherein, The interconnection structure comprises a first busbar.

20. A method of manufacturing a back contact cell, characterized by, Comprising: providing a semiconductor substrate; The semiconductor substrate has opposite first and second faces; the first face has first and second regions arranged alternately; A first doped portion is formed in the first region; A second doped portion is formed on the first face; the second doped portion includes a second doped portion A located in the second region, and a second doped portion B located above a portion of the first doped portion away from the semiconductor substrate; the second doped portion and the first doped portion have opposite conductive types; The second doped portion B and the first doped portion are spaced apart in the thickness direction of the semiconductor substrate; A plurality of interconnection structures are formed on the side of the first doped portion away from the semiconductor substrate; the interconnection structures are electrically connected to the first doped portion; at least part of each second doped portion B is located between the first doped portion and the corresponding interconnection structure, and the second doped portion B and the interconnection structure are insulated from each other.

21. The method of manufacturing a back contact cell according to claim 20, wherein, In the case where the material of the first doped portion includes silicon, the first doped portion formed in the first region includes: A first doped semiconductor layer is formed on one side of the first face in an integral layer; An insulating mask layer is formed on the portion of the first doped semiconductor layer corresponding to the first region; Under the masking effect of the insulating mask layer, the portion of the first doped semiconductor layer located at least in the second region is removed; the remaining first doped semiconductor layer located on the first region forms the first doped portion; the portion of the insulating mask layer located between the first doped portion and the second doped portion B is a first insulating layer; the second doped portion B is spaced apart from the first doped portion by the first insulating layer.

22. The method of manufacturing a back contact cell of claim 20, wherein, The second doped portion formed on one side of the first face includes: A second doped semiconductor layer is formed to cover at least the first doped portion and the second region; and a mask material is formed on one side of the second doped semiconductor layer away from the semiconductor substrate in an integral layer; The mask material is selectively processed so that the portion of the mask material not processed forms a mask layer; the mask layer is located above at least the portion of the second doped semiconductor layer corresponding to the second region and part of the first region; The portion of the mask material subjected to the selective processing is removed; and under the protection of the mask layer, the portion of the second doped semiconductor layer located above part of the first doped portion is selectively removed, so that the remaining second doped semiconductor layer located in the second region forms the second doped portion A, and the remaining second doped semiconductor layer located above at least the portion of the first doped portion away from the semiconductor substrate forms the second doped portion B.

23. The method of manufacturing a back contact cell of claim 20, wherein, After the second doped portion is formed on one side of the first face, before the plurality of interconnection structures are formed on the side of the first doped portion away from the semiconductor substrate, the manufacturing method of the back contact cell further includes: A surface passivation layer is formed to cover the side of the first doped portion away from the semiconductor substrate and the side of the second doped portion away from the semiconductor substrate, obtaining a second insulating layer; the interconnection structures are insulated from each other by the second insulating layer and the second doped portion B.

24. The method of manufacturing a back contact cell of claim 20, wherein, A plurality of the interconnect structures are formed on a side of the first doped portion facing away from the semiconductor substrate using a non-burn-through conductive paste.

25. A photovoltaic module, characterized by, Comprise: The back contact cell of any one of claims 1 to 19 or a back contact cell formed using the manufacturing method of any one of claims 20 to 24; And an intra-string interconnect for interconnecting adjacent back contact cells together.

26. The photovoltaic module of claim 25, wherein, The ratio of the width of at least one of the intra-string interconnects to the width of the second doped portion B comprised by the corresponding back contact cell is greater than or equal to 0.5 and less than or equal to 2.

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