Back contact battery and photovoltaic module

Abstract

The invention discloses a back contact battery and a photovoltaic module, relates to the technical field of photovoltaic, and aims to reduce the hot spot risk of the back contact battery and improve the burning resistance of the back contact battery. A back contact cell includes a semiconductor substrate, a first doped semiconductor layer, a second doped semiconductor layer, and a first transparent conductive layer. The first doped semiconductor layer is disposed on the first region. The doped region is disposed in the first region and the third region of the semiconductor substrate. The doping concentration of the first doping element in the doping region is greater than the doping concentration of the first doping element in the second region of the semiconductor substrate. The second doped semiconductor layer is disposed in the second region and extends to cover at least a part of the doped region. In the third region, the second doped semiconductor layer is electrically connected with the doped region. The first transparent conductive layer covers the second doped semiconductor layer in the second area, and the second doped semiconductor layer in the third area is covered with the first transparent conductive layer extending from the second area.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, and in particular to a back contact cell and a photovoltaic module. Background Art

[0002] A back-contact cell refers to a solar cell in which the light-facing side of the cell has no electrode, and the positive and negative electrodes are arranged on the backlight side of the cell. This can reduce the shading of the electrode to the cell, increase the short-circuit current of the cell, and improve the energy conversion efficiency of the cell.

[0003] In actual use, bird droppings, leaves, sand and dust may fall onto the back-contact battery. The temperature of the battery cell will rise after being blocked, resulting in a hot spot effect. If the temperature of the hot spot exceeds a certain temperature value, it will cause problems such as delamination of the photovoltaic module, burning of the back panel, and cracking of the glass, thus causing the entire solar cell to be scrapped. In severe cases, it may even cause a fire risk. Summary of the invention

[0004] The object of the present invention is to provide a back contact cell and a photovoltaic module, which are used to reduce the risk of hot spots of the back contact cell and improve the anti-burning ability of the back contact cell.

[0005] In order to achieve the above-mentioned object, in a first aspect, the present invention provides a back contact battery, which includes: a semiconductor substrate, a first doped semiconductor layer, a second doped semiconductor layer and a first transparent conductive layer. The semiconductor substrate includes a first surface and a second surface opposite to each other. The first surface includes a first region and a second region alternately distributed, and a third region located between the first region and the second region. The first doped semiconductor layer is arranged on the first region. The doping element in the first doped semiconductor layer is a first doping element. The doping region is arranged in the first region and the third region of the semiconductor substrate. The doping concentration of the first doping element in the doping region is greater than the doping concentration of the first doping element in the second region of the semiconductor substrate. The second doped semiconductor layer is arranged in the second region and extends to cover at least part of the doping region. The conductivity type of the second doped semiconductor layer is opposite to that of the first doped semiconductor layer. In the third region, the second doped semiconductor layer is electrically connected to the doping region. The first transparent conductive layer covers the second doped semiconductor layer located in the second region, and the second doped semiconductor layer located in the third region is covered with the first transparent conductive layer extending from the second region.

[0006] In the case of adopting the above technical solution, when the back contact battery is in working state, the first doped semiconductor layer and the second doped semiconductor layer of opposite conductivity type can effectively shunt and collect carriers, which is conducive to forming photocurrent. The first transparent conductive layer covering the second doped semiconductor layer has a high conductivity, which can timely guide the carriers collected by the second doped semiconductor layer, reduce the carrier recombination rate, and help improve the conversion efficiency of the back contact battery.

[0007] Secondly, the back contact battery also includes a doped region arranged in the first region and the third region of the semiconductor substrate. Since the first doped semiconductor layer is arranged on the first region, the portion of the doped region located in the third region can be exposed outside the first doped semiconductor layer. In addition, the doping concentration of the first doping element in the doping region is greater than the doping concentration of the first doping element in the second region of the semiconductor substrate. At this time, the doping concentration of the first doping element in the doping region is higher, and the doping element in the first doped semiconductor layer is the first doping element. Therefore, the conductivity type of the doping region and the first doped semiconductor layer is the same, and the conductivity type of the doping region and the second doped semiconductor layer is opposite. In addition, the above-mentioned second doped semiconductor layer is not only arranged on the second region, but also extends to cover at least part of the doped region. In the third region, the second doped semiconductor layer can not only passivate the semiconductor substrate, reduce the number of surface defects in the third region, and help improve the conversion efficiency of the back contact battery, but also the second doped semiconductor layer is electrically connected to the doping region, and the two can form a built-in diode with a lower reverse breakdown voltage. In addition, the second doped semiconductor layer located in the third region is covered with a first transparent conductive layer extending from the second region. Based on this, when the back contact battery is blocked, the leakage current can pass through the first doped semiconductor layer, the doped region and the second doped semiconductor layer, and then extend from the second region through the first transparent conductive layer to cover the part above the doped region, and finally be conducted through the electrode that contacts the part of the first transparent conductive layer corresponding to the second region, thereby reducing the risk of hot spots in the back contact battery. Among them, it can be seen from the above content that the leakage current needs to be conducted between the first doped semiconductor layer and the second doped semiconductor layer through the doped region arranged in the semiconductor substrate. Compared with the transmission of the doped semiconductor layer, the lateral conduction ability of the semiconductor substrate is stronger. Therefore, the back contact battery provided by the present invention is more conducive to the transmission of reverse leakage current when blocked, reduces the transmission loss of reverse leakage current, and improves the anti-burning ability of the back contact battery. In addition, the above leakage current not only needs to flow through the PN junction formed by the doped region and the second doped semiconductor layer of opposite conductivity type, but also needs to flow through the high-low junction formed by the doped region and the first doped semiconductor layer of the same conductivity type. Compared with the solution in which the leakage current only flows through the PN junction, during the process in which the back-contact battery provided by the present invention is blocked, under the action of the two electric fields of the PN junction and the high-low junction, it is more conducive to controlling the size of the reverse leakage current, reducing the carrier recombination loss of the back-contact battery, balancing the hot spot risk and conversion efficiency of the back-contact battery, and improving the working performance of the back-contact battery.

[0008] As a possible implementation scheme, the surface of the second region is recessed into the semiconductor substrate relative to the surface of the third region to form a groove structure. The portion of the second doped semiconductor layer corresponding to the second region is located in the groove structure.

[0009] In the case of adopting the above technical solution, there is a groove structure in the second region, and at least part of the side wall of the doped region close to the second region can be exposed to the outside through the groove structure. Based on this, when the second doped semiconductor layer extends from the bottom surface of the groove structure to the side wall of the groove structure and the surface of the third region in sequence, the second doped semiconductor layer can not only be electrically connected to the doped region at the surface of the third region along the thickness direction of the semiconductor substrate, but also can be electrically connected at at least part of the side wall of the groove structure, which is conducive to increasing the leakage contact area and leakage current between the second doped semiconductor layer and the doped region, and further reducing the risk of hot spots of the back contact battery. At the same time, in the actual manufacturing process, if the doped region is formed by internal expansion when forming the first doped semiconductor layer, then the groove structure is formed in the second region, and at least part of the doped region formed in the second region when the entire layer forms the first doped semiconductor layer can also be removed, reducing the carrier recombination between the doped region and the second doped semiconductor layer in the second region, which is conducive to improving the conversion efficiency of the back contact battery.

[0010] As a possible implementation solution, along the thickness direction of the semiconductor substrate, a depth of the groove structure recessed into the semiconductor substrate relative to the surface of the first region is greater than a doping depth of the doping region.

[0011] When the above technical solution is adopted, all parts of the sidewall of the doped region close to the second region along the thickness direction of the semiconductor substrate can be exposed to the outside through the groove structure, further increasing the leakage contact area and leakage current between the second doped semiconductor layer and the doped region, and further reducing the risk of hot spots in the back contact battery. In addition, in the actual manufacturing process, if the doped region is formed by internal expansion when the first doped semiconductor layer is formed, then when the depth of the groove structure recessed into the semiconductor substrate relative to the surface of the first region is greater than the doping depth of the doped region, it indicates that the doped region formed in the second region has been completely removed, reducing the carrier recombination in the second region, so that the second doped semiconductor layer located in the second region has a higher carrier collection efficiency, which is beneficial to improve the conversion efficiency of the back contact battery.

[0012] As a possible implementation scheme, the sidewall of the groove structure is arranged to be inclined relative to the surface of the third region, and the groove width of the groove structure is greater than the groove bottom width.

[0013] In the case of adopting the above technical solution, under the condition that other factors are the same, compared with the side wall of the groove structure being vertically arranged relative to the surface of the third region, when the side wall of the groove structure is arranged obliquely relative to the surface of the third region, the area exposed by the side of the doped region close to the second region through the inclined side wall of the groove structure is larger, which is conducive to further increasing the leakage contact area and leakage current between the second doped semiconductor layer and the doped region. In addition, when the side wall of the groove structure is inclined relative to the surface of the third region, and the notch width of the groove structure is greater than the groove bottom width, the height variation of the inclined side wall of the groove structure is more moderate, which is conducive to the coating of the second doped semiconductor layer on the side wall of the groove structure, improving the electrical connection performance between the part of the second doped semiconductor layer covering the side wall of the groove structure and the doped region, further reducing the risk of hot spots of the back contact battery, and at the same time, it is also conducive to improving the passivation effect of the second doped semiconductor layer on the side wall of the groove structure, and improving the conversion efficiency of the back contact battery.

[0014] As a possible implementation solution, the height difference between the bottom surface of the groove structure and the surface of the third region is greater than or equal to 200 nm and less than or equal to 20 μm.

[0015] In the case of adopting the above technical solution, the height difference between the bottom surface of the groove structure and the surface of the third region is within the above range, which is conducive to preventing the sidewall of the doped region close to the second region from being exposed through the sidewall of the groove structure due to the small height difference, which makes the recessed depth of the groove structure small. It is conducive to the second doped semiconductor layer having a relatively large leakage contact area between the sidewall of the groove structure and the doped region, reducing the risk of hot spots; secondly, if the doped region is formed by internal expansion when forming the first doped semiconductor layer, it can also prevent the doped region formed in the second region from having a small corresponding removal amount when the groove structure is opened due to the small height difference, further reducing the carrier recombination between the doped region and the second doped semiconductor layer in the second region, which is conducive to improving the conversion efficiency of the back contact battery. In addition, it can also prevent the recessed depth of the groove structure from being large due to the large height difference, which is conducive to the part of the semiconductor substrate corresponding to the second region having a large light absorption depth, further improving the conversion efficiency of the back contact battery.

[0016] As a possible implementation solution, the surface of the third region is recessed into the semiconductor substrate relative to the surface of the first region, and the recessed depth is less than the doping depth of the doping region.

[0017] When the above technical solution is adopted, under the condition that other factors are the same, when the surface of the third region is also recessed into the semiconductor substrate relative to the surface of the first region, it is beneficial to reduce the height difference between the surface of the third region and the bottom surface of the groove structure, and is beneficial to the coating of the second doped semiconductor layer on the side wall of the groove structure and the surface of the third region, thereby improving the electrical connection performance between the second doped semiconductor layer and the doped region, further reducing the hot spot risk of the back contact battery, and at the same time, it is also beneficial to improve the passivation effect of the second doped semiconductor layer on the side wall of the groove structure and the surface of the third region, thereby improving the conversion efficiency of the back contact battery. In addition, in the actual manufacturing process, if the doping region is formed by internal expansion when forming the first doped semiconductor layer, the doping concentration of the first doping element in the doping region at the surface of the third region is relatively high, and as the doping depth increases, the doping concentration of the first doping element in the doping region will decrease. Therefore, when the surface of the third region is recessed into the semiconductor substrate relative to the surface of the first region, the doping concentration of the doping region at the surface of the third region can be reduced, which is beneficial to reducing the leakage current between the doping region and the second doped semiconductor layer, and further improving the conversion efficiency of the back contact battery; at the same time, the recessed depth of the surface of the third region relative to the surface of the first region into the semiconductor substrate is less than the doping depth of the doping region, which can ensure that the doping region can be electrically connected to the second doped semiconductor layer at the surface of the third region, so that there is a larger leakage contact area between the doping region and the second doped semiconductor layer, which is beneficial to the back contact battery having a higher anti-burning ability.

[0018] As a possible implementation solution, a height difference between a surface of the third region and a surface of the first region is greater than or equal to 10 nm and less than or equal to 2 μm.

[0019] In the case of adopting the above technical solution, when the height difference between the surface of the third region and the surface of the first region is within the above range, it can prevent the second doped semiconductor layer from being poorly formed at the side wall of the groove structure and the surface of the third region due to the large height difference between the surface of the third region and the bottom surface of the groove structure caused by the small height difference, thereby improving the electrical connection performance between the second doped semiconductor layer and the doped region, further reducing the risk of hot spots of the back contact battery, and at the same time, it is also beneficial to improve the passivation effect of the second doped semiconductor layer on the side wall of the groove structure and the surface of the third region. In addition, it can also prevent the doping depth of the doped region at the third region from being small due to the large height difference, thereby reducing the transmission loss of the leakage current at the doped region. In addition, in the actual manufacturing process, if the doped region is formed by internal expansion when forming the first doped semiconductor layer, then under the same other factors, the greater the height difference between the surface of the third region and the surface of the first region, the smaller the doping depth of the doped region at the third region, and the smaller the doping concentration at the surface of the third region, thereby affecting the leakage current between the doped region and the second doped semiconductor layer in the third region. Based on this, according to the requirements of different actual application scenarios, if there are fewer obstructions such as sand and dust in the installation environment of the back contact battery, the above-mentioned height difference can be set within a larger range, so that the doping concentration of the doping region at the surface of the third region is smaller, which is beneficial to reduce the leakage current of the doping region and the second doped semiconductor layer, and is beneficial to the back contact battery having a higher conversion efficiency; and when there are more obstructions such as sand and dust in the installation environment of the back contact battery, the above-mentioned height difference can be set within a smaller range, so that the doping concentration of the doping region at the surface of the third region is larger, which is beneficial to increase the leakage current of the doping region and the second doped semiconductor layer, and further improve the anti-burning ability of the back contact battery. In summary, by controlling the height difference between the surface of the third region and the surface of the first region, the leakage current of the doping region and the second doped semiconductor layer can be regulated, thereby improving the applicability of the back contact battery in different application scenarios.

[0020] As a possible implementation scheme, the doping concentration of the first doping element at the surface of the doping region corresponding to the third region is greater than or equal to 8×10 9 / cm 3 , and less than or equal to 9×10 20 / cm 3 .

[0021] In the case of adopting the above technical solution, the doping concentration of the first doping element at the surface of the third region corresponding to the doping region will affect the conductive characteristics of the doping region. It can be understood that the smaller the doping concentration of the first doping element at the surface of the third region corresponding to the doping region, the relatively lower the conductive performance of the doping region, which makes the transmission loss of the reverse leakage current higher, but the conversion efficiency of the back contact battery is higher at this time. The greater the doping concentration of the first doping element at the surface of the third region corresponding to the doping region, the relatively higher the conductive performance of the doping region, which is conducive to the transmission of the reverse leakage current, and the hot spot risk of the back contact battery is low at this time. Based on this, the leakage current of the doping region and the second doped semiconductor layer can be regulated by controlling the doping concentration of the first doping element at the surface of the third region corresponding to the doping region, thereby improving the applicability of the back contact battery in different application scenarios, and at the same time facilitating the balanced regulation of the conversion efficiency and hot spot risk of the back contact battery, thereby improving the working performance of the back contact battery.

[0022] As a possible implementation solution, along the distribution direction of the alternating intervals between the first region and the second region, the width of the third region is greater than or equal to 1 nm and less than or equal to 2 μm.

[0023] When the above technical solution is adopted, the width of the third region will affect the size of the leakage contact area between the doped region and the second doped semiconductor layer. When the ratio between the width of the second doped semiconductor layer extending to the third region and the width of the third region is constant, the larger the width of the third region, the larger the leakage contact area between the doped region and the second doped semiconductor layer, and the hot spot risk of the back contact battery is lower. When the width of the third region is smaller, the leakage contact area between the doped region and the second doped semiconductor layer is smaller, and the conversion efficiency of the back contact battery is higher. Based on this, the leakage contact area and leakage current of the doped region and the second doped semiconductor layer can be regulated by controlling the width of the third region, thereby improving the applicability of the back contact battery in different application scenarios, and at the same time facilitating the balanced regulation of the conversion efficiency and hot spot risk of the back contact battery, thereby improving the working performance of the back contact battery.

[0024] As a possible implementation solution, the doping concentration of the first doping element at the surface of the doping region corresponding to the third region is lower than the doping concentration of the first doping element at the surface of the doping region corresponding to the first region.

[0025] When the above technical solution is adopted, it is beneficial to reduce the conduction characteristics at the surface of the doped region corresponding to the third area, and to control the leakage current between the doped region and the second doped semiconductor layer, thereby improving the conversion efficiency of the back contact battery.

[0026] As a possible implementation scheme, the doping element in the second doped semiconductor layer is the second doping element. Along the direction from the first surface to the second surface, the doping concentration of the second doping element in each part of the second region of the semiconductor substrate is the same. In this case, there is no inner diffusion doping region of the same conductivity type as the second doped silicon layer in the second region of the semiconductor substrate, which can prevent the above-mentioned doping region from being electrically in contact with the inner diffusion doping region of the opposite conductivity type to itself, resulting in an excessively high carrier recombination rate, which is beneficial for the back contact battery to have a higher conversion efficiency. At the same time, it can also prevent the doping concentration of the above-mentioned doping region in the third region from being low due to the formation of an inner diffusion doping region in the part of the second doped semiconductor layer covering the third region, which is beneficial for the back contact battery to have a higher anti-burning ability.

[0027] As a possible implementation scheme, the back contact cell includes a first interface passivation layer. The first interface passivation layer is located between the first doped semiconductor layer and the semiconductor substrate.

[0028] When the above technical solution is adopted, the passivation contact structure composed of the first interface passivation layer and the first doped semiconductor layer has an excellent interface passivation effect, and can realize the selective collection of carriers, reduce the carrier recombination rate in the first region of the first surface of the semiconductor substrate, and further improve the photoelectric conversion efficiency of the back contact battery. Optionally, the first interface passivation layer is a tunneling passivation layer.

[0029] As a possible implementation scheme, the back contact cell further includes a second interface passivation layer. The second interface passivation layer is at least located between the second doped semiconductor layer and the semiconductor substrate.

[0030] When the above technical solution is adopted, the passivation contact structure composed of the second interface passivation layer and the portion of the second doped semiconductor layer located on the second region can realize selective collection of carriers and reduce the carrier recombination rate in the second region of the first surface of the semiconductor substrate.

[0031] As a possible implementation solution, the second interface passivation layer is an intrinsic semiconductor passivation layer.

[0032] In the case of adopting the above technical solution, when the second interface passivation layer is an intrinsic semiconductor layer passivation layer, the second interface passivation layer and the second doped semiconductor layer can constitute a heterogeneous contact structure, which has a passivation effect superior to the tunneling passivation contact structure, and can further reduce the carrier recombination rate at the interface between the semiconductor substrate and the second interface passivation layer, which is beneficial to improve the photoelectric conversion efficiency of the back contact battery. In addition, when the second interface passivation layer is an intrinsic semiconductor layer passivation layer, it indicates that the doping elements in the second doped semiconductor layer have not diffused into the semiconductor substrate through the second interface passivation layer. At this time, the application principle of the beneficial effect in this case can refer to the application principle of the beneficial effect of the same doping concentration of the second doping element in each part of the second region of the semiconductor substrate along the direction from the first surface to the second surface as described above, which will not be repeated here.

[0033] As a possible implementation scheme, the doping concentration of the first doping element on the side of the doping region close to the first doping semiconductor layer is less than or equal to the doping concentration of the first doping element in the first doping semiconductor layer. In this case, it is beneficial for the first doped semiconductor layer to have a higher field passivation effect and improve the carrier collection ability of the first doped silicon layer. In addition, it is also beneficial to form a high-low junction between the first doped semiconductor layer and the doping region. The existence of the high-low junction is beneficial to control the magnitude of the reverse leakage current, so that the back contact battery has a higher conversion efficiency. At the same time, when the doping concentration of the first doping element on the side of the doping region close to the first doping semiconductor layer is less than or equal to the doping concentration of the first doping element in the first doping semiconductor layer, in the actual manufacturing process, the doping region can also be formed by internal expansion when the first doping semiconductor layer is formed, and there is no need to use other additional manufacturing processes to form the doping region, thereby simplifying the manufacturing process of the back contact battery and improving the manufacturing efficiency of the back contact battery.

[0034] As a possible implementation scheme, the doping concentration of the first doping element in the doping region is greater than or equal to 8×10 9 / cm 3 , and less than or equal to 9×10 20 / cm 3 The application principle of the beneficial effect in this case can refer to the above-mentioned doping concentration of the first doping element at the surface of the doping region corresponding to the third region being greater than or equal to 8×10 9 / cm 3 , and less than or equal to 9×10 20 / cm 3 The application principle of the beneficial effect will not be repeated here.

[0035] As a possible implementation scheme, the doping concentration of the first doping element in the doping region gradually increases along the direction from the second surface to the first surface. In this case, along the direction from the second surface to the first surface, a high-low junction can be formed between different regions of the doping layer, and the built-in electric field of the high-low junction is consistent with the induced direction of the first doped semiconductor layer, which can improve the collection efficiency of the first doped semiconductor layer for carriers, further reduce the carrier recombination rate, and help improve the conversion efficiency of the back contact battery. In addition, the surface of the doping region away from the semiconductor substrate can also have a higher doping concentration, which is conducive to increasing the leakage current between the doping region and the second doped semiconductor layer, and further reducing the risk of hot spots in the back contact battery.

[0036] As a possible implementation scheme, the edges of the second doped semiconductor layer extending from the second region and the first transparent conductive layer extending from the second region are both located in the third region. Alternatively, the second doped semiconductor layer extending from the second region continues to extend into the first region; and the edge of the first transparent conductive layer extending from the second region is located in the third region. Alternatively, the second doped semiconductor layer extending from the second region and the first transparent conductive layer extending from the second region both continue to extend into the first region, and in the first region, the first transparent conductive layer extending from the second region is located on the second doped semiconductor layer.

[0037] When the above technical solution is adopted, there are many examples of edge setting positions of the second doped semiconductor layer extending from the second region and the first transparent conductive layer extending from the second region, which is conducive to reducing the difficulty of the manufacturing process. At the same time, the extension coverage range of the second doped semiconductor layer and the first transparent conductive layer can be determined according to the requirements of different practical application scenarios (such as when the edges of the second doped semiconductor layer extending from the second region and the first transparent conductive layer extending from the second region are both located in the third region, the leakage current between the first doped semiconductor layer, the doped region and the second doped semiconductor layer is relatively small. When the second doped semiconductor layer extending from the second region and the first transparent conductive layer extending from the second region continue to extend into the first region, and in the first region, the first transparent conductive layer extending from the second region is located on the second doped semiconductor layer, it is conducive to increasing the leakage current between the first doped semiconductor layer, the doped region and the second doped semiconductor layer), thereby realizing the control of the leakage current size between the first doped semiconductor layer, the doped region and the second doped semiconductor layer, realizing the balanced regulation of the conversion efficiency and hot spot risk of the back contact battery, and improving the working performance of the back contact battery.

[0038] As a possible implementation scheme, when the second doped semiconductor layer extending from the second region and the first transparent conductive layer extending from the second region both continue to extend into the first region, the back contact battery also includes an insulating layer, and the insulating layer is arranged between the first doped semiconductor layer and the second doped semiconductor layer located in the first region.

[0039] When the above technical solution is adopted, the insulating layer is arranged between the first doped semiconductor layer and the second doped semiconductor layer located in the first region, which can electrically insulate the two, which is beneficial to control the size of the leakage contact area, so that the back contact battery has a higher conversion efficiency.

[0040] As a possible implementation scheme, the back contact battery further includes a second transparent conductive layer, which covers the first doped semiconductor layer. The second transparent conductive layer is physically insulated from the first transparent conductive layer. Furthermore, when the edges of the second doped semiconductor layer extending from the second region and the first transparent conductive layer extending from the second region are both located in the first region, a through insulating groove is provided in the second doped semiconductor layer located in the first region, and the insulating groove separates the second doped semiconductor layer located in the first region into a first doped portion and a second doped portion, and the second doped portion is closer to the second region than the first doped portion. The second transparent conductive layer also extends onto the first doped portion.

[0041] When the above technical solution is adopted, the presence of the second transparent conductive layer can reduce the contact barrier between the first doped semiconductor layer and the corresponding electrode, and reduce the transmission loss of carriers between the first doped semiconductor layer and the corresponding electrode. In addition, when the edges of the second doped semiconductor layer extending from the second region and the first transparent conductive layer extending from the second region are both located in the first region, at least a larger leakage contact area can be provided between the second doped semiconductor layer and the doped region, thereby reducing the risk of hot spots of the back contact battery. In addition, an insulating groove is provided through the second doped semiconductor layer located in the first region to ensure that the second transparent conductive layer and the first transparent conductive layer are physically insulated to prevent short circuits. The second transparent conductive layer also extends to the first doped portion away from the second region, ensuring that the second transparent conductive layer has a larger coverage area on the first doped semiconductor layer, which is beneficial to the collection and conduction of carriers, and further improves the conversion efficiency of the back contact battery.

[0042] In a second aspect, the present invention provides a photovoltaic module, which includes a back-contact cell provided by the first aspect and various implementations thereof.

[0043] The beneficial effects of the second aspect of the present invention and its various implementations can be analyzed by referring to the beneficial effects of the first aspect and its various implementations, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0045] Figure 1 A schematic longitudinal cross-sectional view of the structure of a back contact battery provided in an embodiment of the present invention Figure 1 ;

[0046] Figure 2 A schematic longitudinal cross-sectional view of the structure of a back contact battery provided in an embodiment of the present invention Figure 2 ;

[0047] Figure 3 A schematic longitudinal cross-sectional view of the structure of a back contact battery provided in an embodiment of the present invention Figure 3 ;

[0048] Figure 4 A schematic longitudinal cross-sectional view of the structure of a back contact battery provided in an embodiment of the present invention Figure 4 ;

[0049] Figure 5 A schematic longitudinal cross-sectional view of the structure of a back contact battery provided in an embodiment of the present invention Figure 5 ;

[0050] Figure 6 A schematic longitudinal cross-sectional view of the structure of a back contact battery provided in an embodiment of the present invention Figure 6 ;

[0051] Figure 7 A schematic longitudinal cross-sectional view of the structure of a back contact battery provided in an embodiment of the present invention Figure 7 ;

[0052] Figure 8 A schematic longitudinal cross-sectional view of the structure of a back contact battery provided in an embodiment of the present invention Figure 8 ;

[0053] Fig. 9 A schematic longitudinal cross-sectional view of the structure of a back contact battery provided in an embodiment of the present invention Figure 9 ;

[0054] Fig.10 A schematic longitudinal cross-sectional view of the structure of a back contact battery provided in an embodiment of the present invention Figure 10 ;

[0055] Fig.11 A schematic longitudinal cross-sectional view of the structure of a back contact battery provided in an embodiment of the present invention Figure 10 one;

[0056] Fig.12 A schematic longitudinal cross-sectional view of the structure of a back contact battery provided in an embodiment of the present invention Figure 10 two;

[0057] Fig.13 A schematic longitudinal cross-sectional view of the structure of a back contact battery provided in an embodiment of the present invention Figure 10 three;

[0058] Fig.14 A schematic longitudinal cross-sectional view of the structure of a back contact battery provided in an embodiment of the present invention Figure 10 Four;

[0059] Fig.15 A schematic longitudinal cross-sectional view of the structure of a back contact battery provided in an embodiment of the present invention Figure 10 five.

[0060] Figure numerals: 11 is a semiconductor substrate, 12 is a first doped semiconductor layer, 13 is a doped region, 14 is a second doped semiconductor layer, 15 is a first transparent conductive layer, 16 is a first region, 17 is a second region, 18 is a third region, 19 is a groove structure, 20 is a first interface passivation layer, 21 is a second interface passivation layer, 22 is an insulating layer, 23 is a second transparent conductive layer, 24 is an insulating groove, 25 is a first doped portion, and 26 is a second doped portion. DETAILED DESCRIPTION

[0061] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concept of the present invention.

[0062] Various structural schematic diagrams according to embodiments of the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for a clearer expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0063] In the context of the present invention, when a layer / element is referred to as being "on" another layer / element, the layer / element may be directly on the other layer / element, or there may be an intermediate layer / element between them. In addition, if a layer / element is "on" another layer / element in one orientation, then when the orientation is reversed, the layer / element may be "under" the other layer / element. In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0064] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The meaning of "several" is one or more, unless otherwise clearly and specifically defined.

[0065] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0066] In a first aspect, an embodiment of the present invention provides a back contact battery. Figure 1As shown, the back contact cell includes: a semiconductor substrate 11, a first doped semiconductor layer 12, a second doped semiconductor layer 14 and a first transparent conductive layer 15. The semiconductor substrate 11 includes a first surface and a second surface opposite to each other. The first surface includes a first region 16 and a second region 17 that are alternately spaced and distributed, and a third region 18 located between the first region 16 and the second region 17. The first doped semiconductor layer 12 is disposed on the first region 16. The doping element in the first doped semiconductor layer 12 is a first doping element. The doping region 13 is disposed in the first region 16 and the third region 18 of the semiconductor substrate 11. The doping concentration of the first doping element in the doping region 13 is greater than the doping concentration of the first doping element in the second region 17 of the semiconductor substrate 11. The second doped semiconductor layer 14 is disposed in the second region 17 and extends to cover at least a portion of the doping region 13. The conductivity type of the second doped semiconductor layer 14 is opposite to that of the first doped semiconductor layer 12. In the third region 18, the second doped semiconductor layer 14 is electrically connected to the doping region 13. The first transparent conductive layer 15 covers the second doped semiconductor layer 14 located in the second region 17 , and the second doped semiconductor layer 14 located in the third region 18 is covered with the first transparent conductive layer 15 extending from the second region 17 .

[0067] When the above technical solution is adopted, when the back contact battery is in working state, the first doped semiconductor layer and the second doped semiconductor layer with opposite conductivity types can effectively shunt and collect carriers, which is conducive to the formation of photocurrent. The first transparent conductive layer covering the second doped semiconductor layer has a high conductivity and can timely guide the carriers collected by the second doped semiconductor layer, reduce the carrier recombination rate, and help improve the conversion efficiency of the back contact battery. Secondly, if Figure 1As shown, the back contact cell also includes a doping region 13 disposed in the first region 16 and the third region 18 of the semiconductor substrate 11. Since the first doped semiconductor layer 12 is disposed on the first region 16, the portion of the doping region 13 located in the third region 18 can be exposed outside the first doped semiconductor layer 12. In addition, the doping concentration of the first doping element in the doping region 13 is greater than the doping concentration of the first doping element in the second region 17 of the semiconductor substrate 11. At this time, the doping concentration of the first doping element in the doping region 13 is higher, and the doping element in the first doped semiconductor layer 12 is the first doping element. Therefore, the conductivity type of the doping region 13 and the first doped semiconductor layer 12 is the same, and the conductivity type of the doping region 13 and the second doped semiconductor layer 14 is opposite. In addition, the second doped semiconductor layer 14 is not only disposed on the second region 17, but also extends to cover at least a portion of the doping region 13. In the third region 18, the second doped semiconductor layer 14 can not only passivate the semiconductor substrate 11, reduce the number of surface defects in the third region 18, and help improve the conversion efficiency of the back contact battery, but also the second doped semiconductor layer 14 is electrically connected to the doped region 13, and the two can form a built-in diode with a lower reverse breakdown voltage. In addition, the second doped semiconductor layer 14 located in the third region 18 is covered with a first transparent conductive layer 15 extending from the second region 17. Based on this, when the back contact battery is blocked, the leakage current can pass through the first doped semiconductor layer 12, the doped region 13 and the second doped semiconductor layer 14, and then through the first transparent conductive layer 15 extending from the second region 17 to the part above the doped region 13, and finally be conducted through the electrode in contact with the part of the first transparent conductive layer 15 corresponding to the second region 17, thereby reducing the risk of hot spots in the back contact battery. Among them, it can be seen from the above that the leakage current needs to be conducted between the first doped semiconductor layer 12 and the second doped semiconductor layer 14 through the doped region 13 set in the semiconductor substrate 11. Compared with the transmission of the doped semiconductor layer, the lateral conduction capability of the semiconductor substrate 11 is stronger. Therefore, the back contact battery provided by the embodiment of the present invention is more conducive to the transmission of the reverse leakage current when it is blocked, reducing the transmission loss of the reverse leakage current and improving the anti-burning capability of the back contact battery. In addition, the above leakage current not only needs to flow through the PN junction formed by the doped region 13 and the second doped semiconductor layer 14 of opposite conductivity types, but also needs to flow through the high-low junction formed by the doped region 13 and the first doped semiconductor layer 12 of the same conductivity type. Compared with the solution in which the leakage current only flows through the PN junction, the back contact battery provided by the embodiment of the present invention is more conducive to controlling the size of the reverse leakage current under the action of the two electric fields of the PN junction and the high-low junction during the process of being blocked, reducing the carrier recombination loss of the back contact battery, balancing the hot spot risk and conversion efficiency of the back contact battery, and improving the working performance of the back contact battery.

[0068] In actual application, the embodiment of the present invention does not specifically limit the material and conductivity type of the semiconductor substrate. For example, the semiconductor substrate may be a silicon substrate. Alternatively, the semiconductor substrate may be a substrate made of any semiconductor material such as a germanium silicon substrate, a germanium substrate or a gallium arsenide substrate. Secondly, the semiconductor substrate may be an N-type semiconductor substrate or a P-type semiconductor substrate.

[0069] Secondly, the semiconductor substrate includes a first surface and a second surface opposite to each other, the first surface of the semiconductor substrate corresponds to the back surface of the back contact battery, and the second surface of the semiconductor substrate corresponds to the front surface of the back contact battery. Among them, the distribution of the first region, the second region and the third region on the first surface can be determined according to the distribution of the first doped semiconductor layer and the second doped semiconductor layer formed on one side of the first surface. Specifically, since the first doped semiconductor layer included in the back contact battery is arranged on the first region, the distribution range of the first region on the first surface can be determined according to the distribution requirements of the first doped semiconductor layer in the actual application scenario. Since part of the second doped semiconductor layer included in the back contact battery is arranged on the second region of the first surface, the distribution range of the second region on the first surface can be determined according to the distribution requirements of the second doped semiconductor layer on the semiconductor substrate in the actual application scenario. It can be understood that the first region roughly corresponds to the first emitter region, and the second region roughly corresponds to the second emitter region. One of the first region and the second region is a P region, and the other is an N region.

[0070] As for the third region, after the range of the first region and the second region in the first surface is determined, the range of the third region is also determined. And along the distribution direction of the alternating intervals of the first region and the second region, the width of the third region will affect the size of the leakage contact area between the doped region and the second doped semiconductor layer. Specifically, when the ratio between the width of the second doped semiconductor layer extending to the third region and the width of the third region is constant, the larger the width of the third region, the larger the leakage contact area between the doped region and the second doped semiconductor layer, and the hot spot risk of the back contact battery is lower. When the width of the third region is smaller, the leakage contact area between the doped region and the second doped semiconductor layer is smaller, and the conversion efficiency of the back contact battery is higher. Based on this, the width of the third region can be determined according to the requirements for the hot spot risk and conversion efficiency of the back contact battery in the actual application scenario, and no specific limitation is made here.

[0071] Exemplarily, along the distribution direction of the alternating intervals between the first region and the second region, the width of the third region may be greater than or equal to 1 nm and less than or equal to 2 μm. For example, the width of the third region may be 1 nm, 10 nm, 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 800 nm, 1 μm, 1.2 μm, 1.5 μm, 1.8 μm or 2 μm, etc. In this case, if there are fewer obstructions such as sand and dust in the installation environment of the back contact battery, the width of the third region may be set within a smaller range, so that the area of ​​the doped region exposed in the third region is smaller, which is conducive to reducing the leakage contact area between the doped region and the second doped semiconductor layer, and is conducive to the back contact battery having a higher conversion efficiency; and when there are more obstructions such as sand and dust in the installation environment of the back contact battery, the width of the third region may be set within a larger range, so that the area of ​​the doped region exposed at the surface of the third region is larger, which is conducive to increasing the leakage contact area between the doped region and the second doped semiconductor layer, and further improving the anti-burning ability of the back contact battery. It can be seen that by controlling the width of the third region, the leakage contact area and leakage current of the doped region and the second doped semiconductor layer can be regulated, thereby improving the applicability of the back-contact battery in different application scenarios. At the same time, it is beneficial to achieve a balanced regulation of the conversion efficiency and hot spot risk of the back-contact battery, thereby improving the working performance of the back-contact battery.

[0072] In terms of surface morphology, Figure 1 As shown, the first surface and the second surface of the semiconductor substrate 11 may be planes. Figure 2 As shown, the second surface of the semiconductor substrate 11 may also be a velvet surface to improve the light trapping effect of the second surface and improve the utilization rate of light by the semiconductor substrate 11. Secondly, the surface of the second region of the first surface may also be a velvet surface to increase the contact area between the second doped semiconductor layer 14 on the second region 17 and the first transparent conductive layer 15 on the second region 17, and to increase the contact area between the first transparent conductive layer 15 on the second region 17 and the corresponding electrode, which is conducive to reducing transmission loss.

[0073] Secondly, if Figure 1 As shown, on the first surface side of the semiconductor substrate 11, the surface of the second region 17 can be flush with the surface of the third region 18, and the portion of the second doped semiconductor layer 14 extending from the second region 17 will only be in electrical contact with the surface of the doped region 13 at the surface of the third region 18. Or, Figure 3As shown, the surface of the second region 17 can also be recessed into the semiconductor substrate 11 relative to the surface of the third region 18 to form a groove structure 19; and the portion of the second doped semiconductor layer 14 corresponding to the second region 17 is located in the groove structure 19. At this time, at least a portion of the sidewall of the doped region 13 close to the second region 17 can be exposed to the outside through the groove structure 19. In this case, when the second doped semiconductor layer 14 extends from the bottom surface of the groove of the groove structure 19 to cover the sidewall of the groove structure 19 and the surface of the third region 18 in sequence, the second doped semiconductor layer 14 can not only be electrically connected to the doped region 13 at the surface of the third region 18 along the thickness direction of the semiconductor substrate 11, but also can be electrically connected at at least a portion of the sidewall of the groove structure 19, which is beneficial to increase the leakage contact area and leakage current between the second doped semiconductor layer 14 and the doped region 13, and further reduce the risk of hot spots of back contact batteries. At the same time, in the actual manufacturing process, if the doped region 13 is formed by internal expansion when the first doped semiconductor layer 12 is formed, a groove structure 19 is formed in the second region 17, and at least part of the doped region 13 formed in the second region 17 when the entire first doped semiconductor layer 12 is formed can be removed, thereby reducing the carrier recombination between the doped region 13 and the second doped semiconductor layer 14 in the second region 17, which is beneficial to improving the conversion efficiency of the back contact battery.

[0074] Among them, Figure 3 As shown, when the surface of the second region 17 is recessed into the semiconductor substrate 11 relative to the surface of the third region 18, the depth of the recessed groove structure 19 relative to the surface of the first region 16 into the semiconductor substrate 11 along the thickness direction of the semiconductor substrate 11 may be greater than the doping depth of the doping region 13. In this case, all parts of the sidewall of the doping region 13 close to the second region 17 along the thickness direction of the semiconductor substrate 11 may be exposed to the outside through the recessed groove structure 19, further increasing the leakage contact area and leakage current between the second doped semiconductor layer 14 and the doping region 13, and further reducing the hot spot risk of the back contact battery. In addition, in the actual manufacturing process, if the doped region 13 is formed by internal expansion when the first doped semiconductor layer 12 is formed, then when the depth of the groove structure 19 recessed into the semiconductor substrate 11 relative to the surface of the first region 16 is greater than the doping depth of the doped region 13, it indicates that the doped region 13 formed in the second region 17 has been completely removed, thereby reducing the carrier recombination in the second region 17, so that the second doped semiconductor layer 14 located in the second region 17 has a higher carrier collection efficiency, which is beneficial to improving the conversion efficiency of the back contact battery.

[0075] Alternatively, along the thickness direction of the semiconductor substrate, the depth of the groove structure recessed into the semiconductor substrate relative to the surface of the first region may also be less than or equal to the doping depth of the doping region. As mentioned above, the recessed depth of the groove structure will not only affect the size of the area that can be exposed by the sidewall of the doping region close to the second region, but also affect the hot spot risk and conversion efficiency of the back contact battery. Moreover, when the doping region is formed by internal expansion when forming the first doped semiconductor layer, the recessed depth of the groove structure will also affect the doping concentration of the first doping element in the second region of the semiconductor substrate and the carrier recombination rate of the back contact battery. Based on this, the specific recessed depth of the groove structure can be determined according to the doping depth of the doping region in the actual application scenario, as well as the requirements for the hot spot risk and conversion efficiency of the back contact battery, and is not specifically limited here.

[0076] Exemplarily, the height difference between the bottom surface of the groove structure and the surface of the third region may be greater than or equal to 200 nm and less than or equal to 20 μm. For example, the height difference between the bottom surface of the groove structure and the surface of the third region may be 200 nm, 300 nm, 500 nm, 800 nm, 1 μm, 2 μm, 5 μm, 8 μm, 10 μm, 15 μm or 20 μm, etc. In this case, the height difference between the bottom surface of the groove structure and the surface of the third region is within the above range, which is conducive to preventing the sidewall of the doped region close to the second region from being exposed through the sidewall of the groove structure due to the small height difference, which makes the recessed depth of the groove structure small. It is conducive to the second doped semiconductor layer having a relatively large leakage contact area between the sidewall of the groove structure and the doped region, reducing the risk of hot spots; secondly, if the doped region is formed by internal expansion when forming the first doped semiconductor layer, it can also prevent the doped region formed in the second region from having a small corresponding removal amount when the groove structure is opened due to the small height difference, further reducing the carrier recombination between the doped region and the second doped semiconductor layer in the second region, which is conducive to improving the conversion efficiency of the back contact battery. In addition, it can also prevent the recessed depth of the groove structure from being large due to the large height difference, which is conducive to the part of the semiconductor substrate corresponding to the second region having a large light absorption depth, further improving the conversion efficiency of the back contact battery.

[0077] In addition, if Figure 3 As shown, when a groove structure 19 is formed in the second region 17, the sidewall of the groove structure 19 may also be perpendicular to the surface of the third region 18; in this case, the area of ​​the side of the doped region 13 close to the second region 17 exposed by the vertical sidewall of the groove structure 19 is relatively small, which is conducive to controlling the leakage current. Or, Figure 4As shown, the sidewall of the groove structure 19 can also be inclined relative to the surface of the third region 18, and the groove width of the groove structure 19 is greater than the groove bottom width. In this case, when other factors are the same, compared with the sidewall of the groove structure 19 being vertically arranged relative to the surface of the third region 18, when the sidewall of the groove structure 19 is inclined relative to the surface of the third region 18, the side of the doped region 13 close to the second region 17 is exposed by the inclined sidewall of the groove structure 19. The area is larger, which is conducive to further increasing the leakage contact area and leakage current between the second doped semiconductor layer 14 and the doped region 13. In addition, when the side walls of the groove structure 19 are inclined relative to the surface of the third region 18 and the groove width of the groove structure 19 is greater than the groove bottom width, the height variation degree of the inclined side walls of the groove structure 19 is more gentle, which is beneficial to the coating of the second doped semiconductor layer 14 on the side walls of the groove structure 19, and improves the electrical connection performance between the part of the second doped semiconductor layer 14 covering the side walls of the groove structure 19 and the doping region 13, further reducing the risk of hot spots of the back contact battery, and at the same time, it is also beneficial to improve the passivation effect of the second doped semiconductor layer 14 on the side walls of the groove structure 19, thereby improving the conversion efficiency of the back contact battery.

[0078] Among them, when the side wall of the groove structure is inclined relative to the surface of the third area, the inclination angle of the side wall of the groove structure relative to the surface of the third area can be determined according to the requirements for the hot spot risk and conversion efficiency of the back contact battery in the actual application scenario, and no specific limitation is made here.

[0079] For the surface heights of the first region and the third region in the first surface, if Figure 4 As shown, the surface of the third region 18 and the surface of the first region 16 may be flush. Figure 5As shown, the surface of the third region 18 may also be recessed into the semiconductor substrate 11 relative to the surface of the first region 16, and the recessed depth is less than the doping depth of the doping region 13. In this case, under the premise that other factors are the same, when the surface of the third region 18 is also recessed into the semiconductor substrate 11 relative to the surface of the first region 16, it is beneficial to reduce the height difference between the surface of the third region 18 and the bottom surface of the groove of the groove structure 19, and to facilitate the coating of the second doped semiconductor layer 14 on the side wall of the groove structure 19 and the surface of the third region 18, thereby improving the electrical connection performance between the second doped semiconductor layer 14 and the doping region 13, further reducing the risk of hot spots of the back contact battery, and at the same time, it is also beneficial to improve the passivation effect of the second doped semiconductor layer 14 on the side wall of the groove structure 19 and the surface of the third region 18, thereby improving the conversion efficiency of the back contact battery. In addition, in the actual manufacturing process, if the doping region 13 is formed by internal expansion when forming the first doped semiconductor layer 12, the doping concentration of the first doping element in the doping region 13 at the surface of the third region 18 is relatively high, and as the doping depth increases, the doping concentration of the first doping element in the doping region 13 will decrease. Therefore, when the surface of the third region 18 is recessed into the semiconductor substrate 11 relative to the surface of the first region 16, the doping concentration of the doping region 13 at the surface of the third region 18 can be reduced, which is beneficial to reducing the leakage current between the doping region 13 and the second doped semiconductor layer 14, and further improving the conversion efficiency of the back contact battery; at the same time, the recessed depth of the surface of the third region 18 relative to the surface of the first region 16 into the semiconductor substrate 11 is less than the doping depth of the doping region 13, which can ensure that the doping region 13 can be electrically connected to the second doped semiconductor layer 14 at the surface of the third region 18, so that there is a larger leakage contact area between the doping region 13 and the second doped semiconductor layer 14, which is beneficial to the back contact battery having a higher anti-burning ability.

[0080] As for the specific depth of the concavity of the surface of the third region into the semiconductor substrate relative to the surface of the first region, it can be determined based on the doping concentration of the doping region at the surface of the third region in the actual application scenario, as well as the hot spot risk and conversion efficiency requirements of the back contact battery, and no specific limitation is made here.

[0081] Exemplarily, the height difference between the surface of the third region and the surface of the first region may be greater than or equal to 10nm and less than or equal to 2μm. The height difference between the surface of the third region and the surface of the first region may be 10nm, 50nm, 100nm, 300nm, 500nm, 800nm, 1μm, 1.2μm, 1.4μm, 1.5μm, 1.8μm or 2μm, etc. In this case, when the height difference between the surface of the third region and the surface of the first region is within the above range, it can prevent the second doped semiconductor layer from being poorly formed at the side wall of the groove structure and the surface of the third region due to the large height difference between the surface of the third region and the bottom surface of the groove structure due to the small height difference, thereby improving the electrical connection performance between the second doped semiconductor layer and the doped region, further reducing the risk of hot spots of the back contact battery, and also helping to improve the passivation effect of the second doped semiconductor layer on the side wall of the groove structure and the surface of the third region. In addition, it can also prevent the doping depth of the doped region at the third region from being small due to the large height difference, thereby reducing the transmission loss of the leakage current at the doped region. In addition, in the actual manufacturing process, if the doping region is formed by internal expansion when forming the first doped semiconductor layer, then when other factors are the same, the greater the height difference between the surface of the third region and the surface of the first region, the smaller the doping depth of the doping region at the third region, and the smaller the doping concentration at the surface of the third region, which in turn affects the leakage current between the doping region and the second doped semiconductor layer in the third region. Based on this, according to the requirements of different actual application scenarios, if there are fewer obstructions such as sand and dust in the installation environment of the back contact battery, the above-mentioned height difference can be set within a larger range, so that the doping concentration of the doping region at the surface of the third region is smaller, which is conducive to reducing the leakage current of the doping region and the second doped semiconductor layer, and is conducive to the back contact battery having a higher conversion efficiency; and when there are more obstructions such as sand and dust in the installation environment of the back contact battery, the above-mentioned height difference can be set within a smaller range, so that the doping concentration of the doping region at the surface of the third region is larger, which is conducive to increasing the leakage current of the doping region and the second doped semiconductor layer, and further improving the anti-burning ability of the back contact battery. In summary, the leakage current of the doped region and the second doped semiconductor layer can be regulated by controlling the height difference between the surface of the third region and the surface of the first region, thereby improving the applicability of the back contact battery in different application scenarios.

[0082] From the doping aspect, the doping region is doped with a first doping element, and the type of the first doping element may be one, such as the first doping element may be phosphorus; or the type of the first doping element may be multiple with the same conductivity type, such as the first doping element may include phosphorus and arsenic. The type of the first doping element in the doping region may be the same as or different from the type of the first doping element in the first doped semiconductor layer. For example: when the conductivity type of the first doped semiconductor layer and the doping region is N-type, the first doping elements in the first doped semiconductor layer and the doping region may all be phosphorus. For another example: when the conductivity type of the first doped semiconductor layer and the doping region is P-type, the first doping elements in the first doped semiconductor layer and the doping region may all be boron. For another example: when the conductivity type of the first doped semiconductor layer and the doping region is N-type, the first doping element in the first doped semiconductor layer may be phosphorus, and the first doping element in the doping region may all be arsenic. It can be understood that if in the actual manufacturing process, the first doping element in the doping region is diffused from the first doped semiconductor layer to the doping region, the type of the first doping element in the first doped semiconductor layer is the same as the type of the first doping element in the doping region.

[0083] In addition, in the actual application process, the doping concentration of the first doping element on the side of the doping region close to the first doped semiconductor layer can be less than or equal to the doping concentration of the first doping element in the first doped semiconductor layer. In this case, it is beneficial for the first doped semiconductor layer to have a higher field passivation effect and improve the carrier collection capacity of the first doped silicon layer. In addition, it is also beneficial to form a high-low junction between the first doped semiconductor layer and the doping region. The existence of the high-low junction is beneficial to control the magnitude of the reverse leakage current, so that the back contact battery has a higher conversion efficiency. At the same time, when the doping concentration of the first doping element on the side of the doping region close to the first doping semiconductor layer is less than or equal to the doping concentration of the first doping element in the first doped semiconductor layer, in the actual manufacturing process, the doping region can also be formed by internal expansion when forming the first doped semiconductor layer, and there is no need to use other manufacturing processes to form the doping region, simplifying the manufacturing process of the back contact battery and improving the manufacturing efficiency of the back contact battery. As for the doping concentration of the first doping element in the doping region, it can be determined according to the requirements for the hot spot risk and conversion efficiency of the back contact battery in the actual application scenario, and no specific limitation is made here.

[0084] For example, the doping concentration of the first doping element in the doping region may be greater than or equal to 8×10 9 / cm 3 , and less than or equal to 9×10 20 / cm 3 For example, the doping concentration of the first doping element in the doping region may be greater than or equal to 8×10 9 / cm 3 ,9×10 9 / cm 3 , 1×10 10 / cm 3 , 1×10 11 / cm 3 , 1×10 12 / cm 3 , 1×10 13 / cm 3 , 1×10 15 / cm 3 , 1×10 17 / cm 3 , 1×10 19 / cm 3 or 9×10 20 / cm 3 Etc. Among them, along the direction from the second surface to the first surface, the doping concentration of the first doping element in each part of the doping region can be the same. Alternatively, the doping concentration of the first doping element in the doping region can also gradually increase along the direction from the second surface to the first surface; in this case, along the direction from the second surface to the first surface, a high-low junction can be formed between different regions of the doping layer, and the built-in electric field of the high-low junction is consistent with the induced direction of the first doped semiconductor layer, which can improve the collection efficiency of the first doped semiconductor layer for carriers, further reduce the carrier recombination rate, and help improve the conversion efficiency of the back contact battery. In addition, the surface of the doping region away from the semiconductor substrate can also have a higher doping concentration, which is beneficial to increase the leakage current between the doping region and the second doped semiconductor layer, and further reduce the risk of hot spots in the back contact battery. Specifically, along the direction from the second surface to the first surface, the doping concentration of the first doping element in each part of the doping region can be set according to the manufacturing process and actual needs of the doping region, and is not specifically limited here.

[0085] As for the doping concentration of the first doping element in the portion of the doping region located in the third region, it is understandable that the doping concentration of the first doping element at the surface of the doping region corresponding to the third region will affect the conductive properties of the doping region. It is understandable that the smaller the doping concentration of the first doping element at the surface of the doping region corresponding to the third region, the lower the conductive properties of the doping region, which makes the transmission loss of the reverse leakage current higher, but the conversion efficiency of the back contact battery is higher at this time. The greater the doping concentration of the first doping element at the surface of the doping region corresponding to the third region, the higher the conductive properties of the doping region, which is beneficial to the transmission of the reverse leakage current, and the risk of hot spots of the back contact battery is lower at this time. In addition, if Figure 5As shown, in the actual manufacturing process, when the first doping element in the doping region 13 is diffused from the first doping semiconductor layer 12 into the doping region 13, whether there is a groove structure 19 in the second region 17 and the depth of the groove structure 19 will also affect the doping concentration of the first doping element at the surface of the third region 18 corresponding to the doping region 13. Therefore, the doping concentration of the first doping element at the surface of the third region 18 corresponding to the doping region 13 can be determined according to the depth of the groove structure 19 in the actual application scenario and the requirements for the hot spot risk and conversion efficiency of the back contact battery, and no specific limitation is made here.

[0086] Exemplarily, the doping concentration of the first doping element at the surface of the third region corresponding to the doping region may be less than the doping concentration of the first doping element at the surface of the first region corresponding to the doping region. In this case, it is beneficial to reduce the conduction characteristics at the surface of the third region corresponding to the doping region, and to control the leakage current between the doping region and the second doped semiconductor layer, thereby improving the conversion efficiency of the back contact battery. Alternatively, the doping concentration of the first doping element at the surface of the third region corresponding to the doping region may also be equal to the doping concentration of the first doping element at the surface of the first region corresponding to the doping region.

[0087] For example, the doping concentration of the first doping element at the surface of the doping region corresponding to the third region may be greater than or equal to 8×10 9 / cm 3 , and less than or equal to 9×10 20 / cm 3 For example, the doping concentration of the first doping element at the surface of the doping region corresponding to the third region may be greater than or equal to 8×10 9 / cm 3 ,9×10 9 / cm 3 , 1×10 10 / cm 3 , 1×10 11 / cm 3 , 1×10 12 / cm 3 , 1×10 13 / cm 3 , 1×10 15 / cm 3 , 1×10 17 / cm 3 , 1×10 19 / cm 3 or 9×10 20 / cm 3Etc. In this case, if there are few obstructions such as sand and dust in the installation environment of the back contact battery, the doping concentration of the first doping element at the surface of the third region corresponding to the doping region can be set within a smaller range, so that the conductive characteristics of the doping region at the surface of the third region are relatively low, which is conducive to reducing the leakage current of the doping region and the second doped semiconductor layer, and is conducive to the back contact battery having a higher conversion efficiency; and when there are many obstructions such as sand and dust in the installation environment of the back contact battery, the doping concentration of the first doping element at the surface of the third region corresponding to the doping region can be set within a smaller range, so that the conductive characteristics of the doping region at the surface of the third region are relatively high, which is conducive to increasing the leakage current of the doping region and the second doped semiconductor layer, and further improving the anti-burning ability of the back contact battery. It can be seen that the leakage current of the doping region and the second doped semiconductor layer can be regulated by controlling the doping concentration of the first doping element at the surface of the third region corresponding to the doping region, thereby improving the applicability of the back contact battery in different application scenarios, and at the same time, it is conducive to achieving a balanced regulation of the conversion efficiency and hot spot risk of the back contact battery, and improving the working performance of the back contact battery.

[0088] As for the second region of the semiconductor substrate, the doping element in the second doped semiconductor layer is defined as the second doping element (the type of the second doping element may be one, such as the second doping element may be boron; or, the type of the second doping element may be multiple with the same conductivity type, such as the second doping element may include boron and aluminum). Along the direction from the first surface to the second surface, the doping concentration of the second doping element in each part of the second region of the semiconductor substrate may be the same. In this case, there is no inner diffusion doping region with the same conductivity type as the second doped silicon layer in the second region of the semiconductor substrate, which can prevent the above-mentioned doping region from being electrically contacted with the inner diffusion doping region with the opposite conductivity type to itself, resulting in excessive carrier recombination rate, which is beneficial for the back contact battery to have a higher conversion efficiency. At the same time, it can also prevent the doping concentration of the above-mentioned doping region in the third region from being low due to the formation of an inner diffusion doping region in the part of the second doped semiconductor layer covering the third region, which is beneficial for the back contact battery to have a higher anti-burning ability.

[0089] For the first doped semiconductor layer, in terms of the conductivity type, the embodiment of the present invention does not specifically limit the conductivity type of the first doped semiconductor layer, as long as the conductivity types of the first doped semiconductor layer and the second doped semiconductor layer are opposite. Specifically, the conductivity type of the first doped semiconductor layer can be N-type, in which case the conductivity type of the second doped semiconductor layer is P-type; or the conductivity type of the first doped semiconductor layer can also be P-type, in which case the conductivity type of the second doped semiconductor layer is N-type.

[0090] In terms of materials, the material of the first doped semiconductor layer may include any semiconductor material such as silicon, silicon germanium, germanium or gallium arsenide. In terms of the arrangement of the material, the crystal phase of the first doped semiconductor layer may be amorphous, microcrystalline, nanocrystalline, single crystal or polycrystalline.

[0091] In terms of the formation position, Figure 1 As shown, the first doped semiconductor layer 12 may be directly disposed on the first region 16. Alternatively, as shown in FIG. Figure 5 As shown, the above-mentioned back contact battery can also include a first interface passivation layer 20 located between the first doped semiconductor layer 12 and the semiconductor substrate 11. In this case, the passivation contact structure composed of the first interface passivation layer 20 and the first doped semiconductor layer 12 has an excellent interface passivation effect, and can realize the selective collection of carriers, reduce the carrier recombination rate of the first region 16 of the first surface of the semiconductor substrate 11, and further improve the photoelectric conversion efficiency of the back contact battery. The material and thickness of the first interface passivation layer 20 can be set according to the material of the first doped semiconductor layer 12 and actual needs, and are not specifically limited here. For example: when the material of the first doped semiconductor layer is doped polysilicon, the first interface passivation layer is a tunneling passivation layer.

[0092] As for the doping concentration of the first doping element in the first doped semiconductor layer, the doping concentration of the first doping element in the first doped semiconductor layer will affect its own field passivation performance; secondly, in the actual manufacturing process, when at least part of the first doping element in the doping region is diffused from the first doped semiconductor layer into the doping region, the doping concentration of the first doping element in the first doping semiconductor layer will also affect the doping concentration of the first doping element in the doping region. Therefore, it can be determined based on the requirements for the field passivation effect of the first doped semiconductor layer and the doping concentration of the first doping element in the doping region in the actual application scenario, and no specific limitation is made here.

[0093] For the second doped semiconductor layer, in terms of materials, the material of the second doped semiconductor layer may include any semiconductor material such as silicon, silicon germanium, germanium or gallium arsenide. In terms of the arrangement of the material, the crystal phase of the second doped semiconductor layer may be amorphous, microcrystalline, nanocrystalline, single crystal or polycrystalline. As for the specific value of the crystallization rate of the second doped semiconductor layer, it can be determined according to the actual application scenario and is not specifically limited here.

[0094] From the doping aspect, the doping concentration of the second doping element in the second doped semiconductor layer directly affects its own conductivity. The conductivity of the second doped semiconductor layer will affect the carrier recombination loss of the back contact battery and the reverse breakdown voltage of the back contact battery when it is blocked. Based on this, the doping concentration of the second doping element in the second doped semiconductor layer can be determined according to the requirements for carrier recombination loss and reverse breakdown voltage in the actual application scenario, and no specific limitation is made here.

[0095] In terms of the formation position, Figure 1 As shown, the second doped semiconductor layer 14 can be directly disposed on the second region 17 and extend to cover at least a portion of the doped region 13. Alternatively, as Figure 5 As shown, the above-mentioned back contact battery can also include a second interface passivation layer 21, which is located between the second region 17 and the second doped semiconductor layer 14 on the first surface, and extends between the second doped semiconductor layer 14 and the doped region 13. In this case, the passivation contact structure composed of the second interface passivation layer 21 and the part of the second doped semiconductor layer 14 located on the second region 17 can realize the selective collection of carriers and reduce the carrier recombination rate of the second region 17 of the first surface of the semiconductor substrate 11. The material and thickness of the second interface passivation layer 21 can be set according to the material of the second doped semiconductor layer 14 and actual needs, and are not specifically limited here. For example: when the material of the second doped semiconductor layer includes doped amorphous silicon, doped microcrystalline silicon and doped nanocrystalline silicon, the second interface passivation layer is an intrinsic amorphous silicon layer, an intrinsic microcrystalline silicon layer, an intrinsic nanocrystalline silicon or a mixed layer of the above three.

[0096] Among them, when the second interface passivation layer is an intrinsic semiconductor layer passivation layer, the second interface passivation layer and the second doped semiconductor layer can constitute a heterogeneous contact structure, which has a passivation effect superior to the tunnel passivation contact structure, and can further reduce the carrier recombination rate at the interface between the semiconductor substrate and the second interface passivation layer, which is beneficial to improve the photoelectric conversion efficiency of the back contact battery. In addition, when the second interface passivation layer is an intrinsic semiconductor layer passivation layer, it indicates that the doping elements in the second doped semiconductor layer have not diffused into the semiconductor substrate through the second interface passivation layer. At this time, the application principle of the beneficial effect in this case can refer to the application principle of the beneficial effect of the same doping concentration of the second doping element in each part of the second region of the semiconductor substrate along the direction from the first surface to the second surface as described above, which will not be repeated here.

[0097] In terms of the scope of formation, Figure 5 and Figure 6As shown, the edge of the second doped semiconductor layer 14 extending from the second region 17 may be located in the third region 18 . In this case, in the third region 18 , the second doped semiconductor layer 14 may only cover a portion of the doped region 13 or may cover the entire doped region 13 .

[0098] Or, if Figure 7 As shown, the second doped semiconductor layer 14 extending from the second region 17 may also continue to extend into the first region 16. In this case, in the first region 16, the second doped semiconductor layer 14 may be electrically connected to the first doped semiconductor layer 12 to increase the leakage contact area and further reduce the hot spot risk of the back contact battery, wherein the extension width of the second doped semiconductor layer 14 in the first region 16 may be set according to actual needs and is not specifically limited here. Or, as Figure 8 As shown, the back contact battery may also include an insulating layer 22, and the insulating layer 22 is disposed between the first doped semiconductor layer 12 and the second doped semiconductor layer 14 located in the first region 16, which can electrically insulate the two, which is beneficial for controlling the size of the leakage contact area, so that the back contact battery has a higher conversion efficiency. The material and thickness of the insulating layer 22 can be set according to actual needs, and are not specifically limited here. For example, the material of the insulating layer 22 may include at least one of silicon oxide, silicon nitride or aluminum oxide.

[0099] For the first transparent conductive layer, the embodiment of the present invention does not specifically limit the material and thickness of the first transparent conductive layer. Exemplarily, the material of the first transparent conductive layer may include at least one of fluorine-doped tin oxide, aluminum-doped zinc oxide, tin-doped indium oxide, tungsten-doped indium oxide, molybdenum-doped indium oxide, cerium-doped indium oxide, and indium hydroxide.

[0100] In terms of the formation range, the formation range of the first transparent conductive layer can be determined according to the formation range of the second doped semiconductor layer and the requirements for the hot spot risk and conversion efficiency of the back contact battery in the actual application scenario, and is not specifically limited here.

[0101] For example, Figure 5 and Figure 6 As shown, when the edge of the second doped semiconductor layer 14 extending from the second region 17 is located in the third region 18, the edge of the first transparent conductive layer 15 extending from the second region 17 is also located in the third region 18. At this time, in the third region 18, the edge of the first transparent conductive layer 15 can be flush with the edge of the second doped semiconductor layer 14; or, the edge of the first transparent conductive layer 15 can also be retracted inwardly along the direction from the first region 16 to the second region 17 relative to the edge of the second doped semiconductor layer 14, and the retracted distance can be determined according to the requirements for the hot spot risk and conversion efficiency of the back contact battery in actual scenarios, and is not specifically limited here.

[0102] For example, Figure 7 , Figure 8 and Fig. 9 As shown, when the second doped semiconductor layer 14 extending from the second region 17 continues to extend into the first region 16, the edge of the first transparent conductive layer 15 extending from the second region 17 may be located in the third region 18. At this time, in the third region 18, the first transparent conductive layer 15 may only cover a portion of the doped region 13, or may cover the entire doped region 13.

[0103] Or, if Fig.10 and Fig.11 As shown, in the case where the second doped semiconductor layer 14 extending from the second region 17 continues to extend into the first region 16, the first transparent conductive layer 15 extending from the second region 17 may also continue to extend into the first region 16, and in the first region 16, the first transparent conductive layer 15 extending from the second region 17 is located on the second doped semiconductor layer 14. At this time, in the first region 16, the edge of the first transparent conductive layer 15 may be flush with the edge of the second doped semiconductor layer 14; or, the edge of the first transparent conductive layer 15 may also be retracted inwardly from the edge of the second doped semiconductor layer 14 along the direction from the first region 16 to the third region 18. The retracted distance may be determined based on the requirements for the hot spot risk and conversion efficiency of the back contact battery in actual scenarios, and is not specifically limited here. Wherein, as Fig.12 As shown, when the second doped semiconductor layer 14 extending from the second region 17 and the first transparent conductive layer 15 extending from the second region 17 continue to extend into the first region 16, the back contact battery can also include the above-mentioned insulating layer 22 to facilitate controlling the size of the leakage contact area, so that the back contact battery has a higher conversion efficiency; at this time, the extension width of the second doped semiconductor layer 14 and the first transparent conductive layer 15 on the first region 16 can be determined according to actual manufacturing requirements, and no specific limitation is made here.

[0104] It is worth noting that Figures 5 to 12As shown, there are multiple examples of edge arrangement positions of the second doped semiconductor layer 14 extending from the second region 17 and the first transparent conductive layer 15 extending from the second region 17, which is conducive to reducing the difficulty of the manufacturing process. The extended coverage range of the second doped semiconductor layer 14 and the first transparent conductive layer 15 can also be determined according to the requirements of different practical application scenarios (for example, when the edges of the second doped semiconductor layer 14 extending from the second region 17 and the first transparent conductive layer 15 extending from the second region 17 are both located in the third region 18, the leakage current between the first doped semiconductor layer 12, the doped region 13 and the second doped semiconductor layer 14 is relatively small. When The second doped semiconductor layer 14 extending from the second region 17 and the first transparent conductive layer 15 extending from the second region 17 both continue to extend into the first region 16. When the first transparent conductive layer 15 extending from the second region 17 is located on the second doped semiconductor layer 14 in the first region 16, it is beneficial to increase the leakage current between the first doped semiconductor layer 12, the doped region 13 and the second doped semiconductor layer 14, thereby achieving control of the leakage current between the first doped semiconductor layer 12, the doped region 13 and the second doped semiconductor layer 14, achieving balanced regulation of the conversion efficiency and hot spot risk of the back contact battery, and improving the working performance of the back contact battery.

[0105] Alternatively, the first doped semiconductor layer may be in direct ohmic contact with the corresponding electrode; or Fig.13 As shown, the back contact battery may also include a second transparent conductive layer 23, and the second transparent conductive layer 23 covers the first doped semiconductor layer 12. The second transparent conductive layer 23 and the first transparent conductive layer 15 are physically insulated. In this case, the presence of the second transparent conductive layer 23 can reduce the contact barrier between the first doped semiconductor layer 12 and the corresponding electrode, and reduce the transmission loss of carriers between the first doped semiconductor layer 12 and the corresponding electrode. The material and thickness of the second transparent conductive layer 23 can refer to the material and thickness of the first transparent conductive layer 15 described above, and will not be repeated here. In actual application, the materials of the first transparent conductive layer 15 and the second transparent conductive layer 23 may be the same or different. The first transparent conductive layer 15 and the second transparent conductive layer 23 may be continuous as a whole, that is, the two are formed simultaneously using the same manufacturing process; or, the first transparent conductive layer 15 and the second transparent conductive layer 23 may be formed separately in different operation steps.

[0106] Wherein, in the case where the second doped semiconductor layer extending from the second region and the edge of the first transparent conductive layer extending from the second region are both located within the first region, and the back contact cell further includes the second transparent conductive layer, as Fig.13As shown, the second transparent conductive layer 23 may only cover the first doped semiconductor layer 12, and the edge of the second transparent conductive layer 23 near the third region 18 and the second doped semiconductor layer 14 may be spaced apart along the arrangement direction of the first region 16 and the second region 17. Alternatively, as Fig.14 As shown, the second transparent conductive layer 23 may also extend onto the second doped semiconductor layer 14, the portion of the second doped semiconductor layer 14 located on the first region 16 is continuously distributed, and the second transparent conductive layer 23 is spaced apart from the edge of the third region 18 and the first transparent conductive layer 15 along the arrangement direction of the first region 16 and the second region 17. Alternatively, as Fig.15 As shown, a penetrating insulating groove 24 is provided in the second doped semiconductor layer 14 located in the first region 16, and the insulating groove 24 separates the second doped semiconductor layer 14 located in the first region 16 into a first doped portion 25 and a second doped portion 26, the second doped portion 26 is closer to the second region 17 than the first doped portion 25, and the second transparent conductive layer 23 also extends onto the first doped portion 25.

[0107] It is worth noting that when the edges of the second doped semiconductor layer extending from the second region and the first transparent conductive layer extending from the second region are both located in the first region, at least a larger leakage contact area can be provided between the second doped semiconductor layer and the doped region, thereby reducing the risk of hot spots of the back contact battery. In addition, an insulating groove is provided through the second doped semiconductor layer located in the first region to ensure that the second transparent conductive layer and the first transparent conductive layer are physically insulated to prevent short circuits. The second transparent conductive layer also extends to the first doped portion away from the second region, ensuring that the second transparent conductive layer has a larger coverage area on the first doped semiconductor layer, which is beneficial to the collection and conduction of carriers, thereby further improving the conversion efficiency of the back contact battery. Among them, the width of the insulating groove can be set according to actual needs and is not specifically limited here.

[0108] In a second aspect, an embodiment of the present invention provides a photovoltaic module, which includes a back-contact cell provided by the first aspect and various implementations thereof.

[0109] The beneficial effects of the second aspect and its various implementations in the embodiments of the present invention can be analyzed with reference to the beneficial effects of the first aspect and its various implementations, and will not be repeated here.

[0110] In the above description, the technical details of the patterning and etching of each layer are not described in detail. However, those skilled in the art should understand that various technical means can be used to form layers, regions, etc. of desired shapes. In addition, in order to form the same structure, those skilled in the art can also design methods that are not completely the same as the methods described above. In addition, although the various embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage.

[0111] The embodiments of the present invention are described above. However, these embodiments are only for a clearer description and are not intended to limit the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents. Without departing from the scope of the present invention, a person skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present invention.

Claims

1. A back contact battery, characterized in that: include: A semiconductor substrate, wherein the semiconductor substrate comprises a first surface and a second surface opposite to each other; the first surface comprises first regions and second regions alternately spaced, and a third region located between the first region and the second region; A first doped semiconductor layer is disposed on the first region; the doping element in the first doped semiconductor layer is a first doping element; a doping region disposed in the first region and the third region of the semiconductor substrate; a doping concentration of the first doping element in the doping region being greater than a doping concentration of the first doping element in the second region of the semiconductor substrate; a second doped semiconductor layer, disposed in the second region and extending to cover at least a portion of the doped region; the second doped semiconductor layer and the first doped semiconductor layer have a conductivity type opposite to that of the first doped semiconductor layer; in the third region, the second doped semiconductor layer is electrically connected to the doped region; The first transparent conductive layer covers the second doped semiconductor layer located in the second region, and the second doped semiconductor layer located in the third region is covered with the first transparent conductive layer extending from the second region.

2. The back contact cell according to claim 1, characterized in that: The surface of the second region is recessed into the semiconductor substrate relative to the surface of the third region to form a groove structure; and a portion of the second doped semiconductor layer corresponding to the second region is located in the groove structure.

3. The back contact battery according to claim 2, characterized in that: Along the thickness direction of the semiconductor substrate, the depth of the groove structure recessed into the semiconductor substrate relative to the surface of the first region is greater than the doping depth of the doping region; And / or, the sidewall of the groove structure is arranged obliquely relative to the surface of the third region, and the groove width of the groove structure is greater than the groove bottom width; And / or, a height difference between a bottom surface of the groove structure and a surface of the third region is greater than or equal to 200 nm and less than or equal to 20 μm.

4. The back contact cell according to claim 2 or 3, characterized in that: The surface of the third region is recessed into the semiconductor substrate relative to the surface of the first region, and the recessed depth is smaller than the depth of the doped region.

5. The back contact cell according to claim 4, characterized in that: A height difference between a surface of the third region and a surface of the first region is greater than or equal to 10 nm and less than or equal to 2 μm; And / or, the doping concentration of the first doping element at the surface of the doping region corresponding to the third region is greater than or equal to 8×10 9 / cm 3 , and less than or equal to 9×10 20 / cm 3 .

6. The back contact cell according to claim 2, characterized in that: Along the distribution direction of the alternating intervals of the first regions and the second regions, a width of the third region is greater than or equal to 1 nm and less than or equal to 2 μm.

7. The back contact cell according to claim 1, characterized in that: A doping concentration of the first doping element at a surface of the doping region corresponding to the third region is lower than a doping concentration of the first doping element at a surface of the doping region corresponding to the first region.

8. The back contact cell according to claim 1, characterized in that: The doping element in the second doped semiconductor layer is a second doping element; Along the direction from the first surface to the second surface, the doping concentration of the second doping element in each part of the second region of the semiconductor substrate is the same.

9. The back contact cell according to claim 1, characterized in that: The back contact cell comprises a first interface passivation layer; the first interface passivation layer is located between the first doped semiconductor layer and the semiconductor substrate; And / or, the back contact cell further includes a second interface passivation layer; the second interface passivation layer is at least located between the second doped semiconductor layer and the semiconductor substrate.

10. The back contact cell according to claim 9, characterized in that: The first interface passivation layer is a tunneling passivation layer; the second interface passivation layer is an intrinsic semiconductor passivation layer.

11. The back contact cell according to claim 1, characterized in that: The doping concentration of the first doping element on the side of the doping region close to the first doping semiconductor layer is less than or equal to the doping concentration of the first doping element in the first doping semiconductor layer; and / or, the doping concentration of the first doping element in the doping region is greater than or equal to 8×10 9 / cm 3 , and less than or equal to 9×10 20 / cm 3 ; And / or, the doping concentration of the first doping element in the doping region gradually increases along the direction from the second surface to the first surface.

12. The back contact cell according to claim 1, characterized in that: The second doped semiconductor layer extending from the second region and the edge of the first transparent conductive layer extending from the second region are both located in the third region; Or, the second doped semiconductor layer extending from the second region continues to extend into the first region; and the edge of the first transparent conductive layer extending from the second region is located in the third region; Alternatively, the second doped semiconductor layer extending from the second region and the first transparent conductive layer extending from the second region both continue to extend into the first region, and in the first region, the first transparent conductive layer extending from the second region is located on the second doped semiconductor layer.

13. The back contact cell according to claim 12, characterized in that: In the case where the second doped semiconductor layer extending from the second region and the first transparent conductive layer extending from the second region both continue to extend into the first region, The back contact cell further includes an insulating layer disposed between the first doped semiconductor layer and the second doped semiconductor layer located in the first region.

14. The back contact cell according to claim 12, characterized in that: The back contact cell further comprises a second transparent conductive layer, the second transparent conductive layer covers the first doped semiconductor layer; the second transparent conductive layer is physically insulated from the first transparent conductive layer; When the second doped semiconductor layer extending from the second region and the edge of the first transparent conductive layer extending from the second region are both located in the first region, an insulating groove is provided through the second doped semiconductor layer located in the first region, and the insulating groove separates the second doped semiconductor layer located in the first region into a first doped portion and a second doped portion, and the second doped portion is closer to the second region than the first doped portion; the second transparent conductive layer also extends onto the first doped portion.

15. A photovoltaic module, characterized in that: Comprising a back contact battery as claimed in any one of claims 1 to 14.

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