A back-contact battery and a photovoltaic module

Abstract

The present invention discloses a back-contact battery and a photovoltaic module, relating to the field of photovoltaic technology, to reduce the hot-spot risk of the back-contact battery and improve the anti-burning ability of the back-contact battery. The back-contact battery 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 a first region. Doped regions are disposed within a first region and a third region of the semiconductor substrate. The doping concentration of the first doping element in the doped regions is greater than the doping concentration of the first doping element in a second region of the semiconductor substrate. The second doped semiconductor layer is disposed on the second region and extends to cover at least a part of the doped regions. In the third region, the second doped semiconductor layer is electrically connected to the doped regions. 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.

Description

Technical Field

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

[0002] A back-contact battery refers to a solar cell in which the light-facing surface of the cell has no electrodes, and the positive and negative electrodes are both disposed on the backlight side of the cell, thereby reducing the shielding of the electrodes to the cell, increasing the short-circuit current of the cell, and improving the energy conversion efficiency of the cell.

[0003] During the actual use of the back-contact battery, there may be obstacles such as bird droppings, leaves, and dust falling on the back-contact battery. After the cell is blocked, the temperature will rise and a hot-spot effect will occur. If the temperature generated by the hot spot exceeds a certain temperature value, it will cause problems such as delamination of the photovoltaic module, burning of the backplane, and bursting of the glass, resulting in the scrapping of the entire solar cell, and may even cause a fire risk in severe cases. Summary of the Invention

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

[0005] To achieve the above purpose, 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 opposite first and second surfaces. The first surface includes alternately and spaced-apart first and second regions, and a third region located between the first and second regions. The first doped semiconductor layer is disposed on the first region. The doping element in the first doped semiconductor layer is a first doping element. Doping regions are provided in the first and third regions of the semiconductor substrate. The doping concentration of the first doping element in the doping regions 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 on the second region and extends to cover at least part of the doping regions. The second doped semiconductor layer has 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 doping regions. 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 a working state, the first doped semiconductor layer and the second doped semiconductor layer with opposite conduction types can effectively shunt and collect carriers, which is beneficial to the formation of photocurrent. The first transparent conductive layer covering the second doped semiconductor layer has high conductivity, and can timely export the carriers collected by the second doped semiconductor layer, reduce the carrier recombination rate, and is beneficial to improving 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. At this time, at least part of the region of the doping region near the side wall of the second region can be exposed through the groove structure. Based on this, when the second doped semiconductor layer extends and covers the side wall of the groove structure and the surface of the third region in sequence from the bottom surface of the groove structure, the second doped semiconductor layer can not only be electrically connected to the doping region at the surface of the third region along the thickness direction of the semiconductor substrate, but also be electrically connected at at least part of the side walls of the groove structure, which is beneficial to increasing the leakage contact area and the leakage current magnitude between the second doped semiconductor layer and the doping region, and further reducing the hot spot risk of the back contact battery. At the same time, in the actual manufacturing process, if the doping region is formed by an in-diffusion method when forming the first doped semiconductor layer, forming a groove structure in the second region can also remove at least part of the region of the doping region formed in the second region when forming the entire first doped semiconductor layer, reducing the carrier recombination between the doping region and the second doped semiconductor layer at the second region, which is beneficial to improving the conversion efficiency of the back contact battery.

[0010] As a possible implementation solution, 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.

[0011] In the case of adopting the above technical solution, each part of the side wall of the doping region near the second region along the thickness direction of the semiconductor substrate can be exposed through the groove structure, further increasing the leakage contact area and the leakage current magnitude between the second doped semiconductor layer and the doping region, and further reducing the hot spot risk of the back contact battery. In addition, in the actual manufacturing process, if the doping region is formed by an in-diffusion method when forming the first doped semiconductor layer, 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 doping region, it indicates that all of the doping region formed in the second region has been removed, reducing the carrier recombination at the second region, so that the second doped semiconductor layer located in the second region has a high carrier collection efficiency, which is beneficial to improving the conversion efficiency of the back contact battery.

[0012] As a possible implementation solution, the side wall of the groove structure is inclined with respect to the surface of the third region, and the width of the groove opening of the groove structure is greater than the width of the groove bottom.

[0013] In the case of adopting the above technical solution, when other factors are the same, compared with the side wall of the groove structure being perpendicular to the surface of the third region, when the side wall of the groove structure is inclined with respect to the surface of the third region, the area of the side of the doping region close to the second region exposed through the inclined side wall of the groove structure is larger, which is beneficial to further increasing the leakage contact area and the leakage current magnitude between the second doped semiconductor layer and the doping region. Additionally, when the side wall of the groove structure is inclined with respect to the surface of the third region and the width of the notch of the groove structure is greater than the width of the bottom of the groove, the degree of height change of the inclined side wall of the groove structure is milder, which is beneficial to the coating of the second doped semiconductor layer on the side wall of the groove structure, improving the electrical connection performance between the portion of the second doped semiconductor layer covering the side wall of the groove structure and the doping region, further reducing the hot spot risk of the back contact battery, and at the same time, it is also beneficial to improving the passivation effect of the second doped semiconductor layer on the side wall of the groove structure and increasing 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, when the height difference between the bottom surface of the groove structure and the surface of the third region is within the above range, it is beneficial to prevent the area of the side wall of the doping region close to the second region exposed through the side wall of the groove structure from being small due to the small height difference resulting in a small recess depth of the groove structure, which is conducive to a relatively large leakage contact area between the second doped semiconductor layer and the doping region at the side wall of the groove structure, reducing the hot spot risk; secondly, if the doping region is formed by an inner expansion method when forming the first doped semiconductor layer, it can also prevent the removal amount corresponding to the doping region formed in the second region from being small due to the small height difference when opening the groove structure, further reducing the carrier recombination between the doping region and the second doped semiconductor layer at the second region, which is beneficial to improving the conversion efficiency of the back contact battery. Additionally, it can also be beneficial to prevent the recess depth of the groove structure from being large due to the large height difference, which is conducive to a relatively large light absorption depth of the portion of the semiconductor substrate corresponding to the second region, 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 with respect to the surface of the first region, and the recess depth is less than the doping depth of the doping region.

[0017] In the case of adopting the above technical solution, when other factors are the same, if 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, which is conducive to the coating of the second doped semiconductor layer on the side wall of the groove structure and the surface of the third region, 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, and improving the conversion efficiency of the back contact battery. In addition, in the actual manufacturing process, if the doped region is formed by the internal diffusion method when the first doped semiconductor layer is formed, the doping concentration of the first doping element in the doped 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 doped 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 doped region at the surface of the third region can be reduced, which is beneficial to reducing the leakage current between the doped 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 doped region, which can ensure that the doped region can be electrically connected to the second doped semiconductor layer at the surface of the third region, so that there is a large leakage contact area between the doped region and the second doped semiconductor layer, which is beneficial to the back contact battery having a high anti-burning ability.

[0018] As a possible implementation solution, the height difference between the surface of the third region and the 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 is possible to prevent the height difference between the surface of the third region and the bottom surface of the groove structure from being large due to the small height difference, resulting in poor formation quality of the second doped semiconductor layer at the side wall of the groove structure and the surface of the third region, improve the electrical connection performance between the second doped semiconductor layer and the doped region, further reduce 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. In addition, it is possible to prevent the doping depth of the doped region at the third region from being small due to the large height difference, and reduce 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 the internal diffusion method when forming the first doped semiconductor layer, under the same other factors, the larger 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 of the doped region at the surface of the third region, thereby affecting the magnitude of 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 dust and other obstacles in the installation environment of the back contact battery, the above height difference can be set within a larger range, so that the doping concentration of the doped region at the surface of the third region is smaller, which is beneficial to reducing the magnitude of the leakage current between the doped region and the second doped semiconductor layer, and is conducive to the back contact battery having a higher conversion efficiency; while when there are more dust and other obstacles in the installation environment of the back contact battery, the above height difference can be set within a smaller range, so that the doping concentration of the doped region at the surface of the third region is larger, which is beneficial to increasing the magnitude of the leakage current between the doped region and the second doped semiconductor layer, and further improving the anti-burning ability of the back contact battery. In summary, the magnitude of the leakage current between 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, and the applicability of the back contact battery in different application scenarios can be improved.

[0020] As a possible implementation solution, the doping concentration of the first doping element corresponding to the surface of the third region in the doped 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, resulting in a higher transmission loss of the reverse leakage current. However, at this time, the conversion efficiency of the back-contact battery is relatively high. On the contrary, the larger 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 beneficial to the transmission of the reverse leakage current. At this time, the hot-spot risk of the back-contact battery is relatively low. Based on this, by controlling the doping concentration of the first doping element at the surface of the third region corresponding to the doping region, the leakage current of the doping region and the second doped semiconductor layer can be regulated, the applicability of the back-contact battery in different application scenarios can be improved, and at the same time, it is beneficial to achieve the balanced regulation of the conversion efficiency and the hot-spot risk of the back-contact battery, thereby improving the working performance of the back-contact battery.

[0022] As a possible implementation, along the distribution direction of the alternating intervals of 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] In the case of adopting the above technical solution, the width of the third region will affect the size of the leakage contact area between the doping region and the second doped semiconductor layer. When the ratio between the width of the second doped semiconductor layer extending into the third region and the width of the third region is fixed, the larger the width of the third region, the larger the leakage contact area between the doping region and the second doped semiconductor layer, and at this time, the hot-spot risk of the back-contact battery is relatively low. On the contrary, when the width of the third region is smaller, the leakage contact area between the doping region and the second doped semiconductor layer is smaller, and at this time, the conversion efficiency of the back-contact battery is relatively high. Based on this, by controlling the width of the third region, the leakage contact area and the leakage current between the doping region and the second doped semiconductor layer can be regulated, the applicability of the back-contact battery in different application scenarios can be improved, and at the same time, it is beneficial to achieve the balanced regulation of the conversion efficiency and the hot-spot risk of the back-contact battery, thereby improving the working performance of the back-contact battery.

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

[0025] In the case of adopting the above technical solution, it is beneficial to reduce the conduction characteristics at the surface of the third region corresponding to the doping region, which is beneficial to controlling the leakage current between the doping region and the second doped semiconductor layer, and thus improving the conversion efficiency of the back-contact battery.

[0026] As a possible implementation solution, 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 in-diffusion doping region with the same conduction type as the second doped silicon layer in the second region of the semiconductor substrate, which can prevent the above-mentioned doping region from making electrical contact with the in-diffusion doping region with the opposite conduction type to itself, resulting in an excessively high carrier recombination rate, and is beneficial for the back contact battery to have a high conversion efficiency. At the same time, it can also prevent the doping concentration of the above-mentioned doping region from being low at the third region due to the formation of an in-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 high anti-burning ability.

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

[0028] In the case of adopting the above technical solution, the passivation contact structure composed of the first interface passivation layer and the first doped semiconductor layer has 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 solution, the back contact battery 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] In the case of adopting the above technical solution, the passivation contact structure composed of the second interface passivation layer and the part of the second doped semiconductor layer located on the second region can realize the 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 form a heterojunction contact structure. This heterojunction contact structure has a passivation effect superior to that of the tunneling passivation contact structure, which can further reduce the carrier recombination rate at the interface between the semiconductor substrate and the second interface passivation layer, and is conducive to improving 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 do not diffuse into the semiconductor substrate through the second interface passivation layer. At this time, the application principle of the beneficial effects in this case can refer to the application principle of the beneficial effects that the doping concentration of the second doping elements in each part of the second region of the semiconductor substrate is the same along the direction from the first surface to the second surface as described above, and will not be elaborated here.

[0033] As a possible implementation solution, the doping concentration of the first doping elements on the side of the doping region close to the first doped semiconductor layer is less than or equal to the doping concentration of the first doping elements in the first doped semiconductor layer. In this case, it is beneficial for the first doped semiconductor layer to have a high field passivation effect and improve the carrier collection ability of the first doped silicon layer. Moreover, it is also beneficial to form a high-low junction between the first doped semiconductor layer and the doping region. The existence of this high-low junction is conducive to controlling the magnitude of the reverse leakage current, making the back contact battery have a high conversion efficiency. At the same time, when the doping concentration of the first doping elements on the side of the doping region close to the first doped semiconductor layer is less than or equal to the doping concentration of the first doping elements in the first doped semiconductor layer, in the actual manufacturing process, the doping region can also be formed by the internal diffusion method when forming the first doped semiconductor layer, without the need to adopt other additional 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.

[0034] As a possible implementation solution, the doping concentration of the first doping elements 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 effects in this case can refer to the application principle of the beneficial effects that the doping concentration of the first doping elements at the surface of the third region corresponding to 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 as described above, and will not be elaborated here.

[0035] As a possible implementation solution, 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, a high-low junction can be formed between different regions of the doping layer along the direction from the second surface to the first surface. The built-in electric field of this high-low junction is consistent with the induced direction of the first doped semiconductor layer, which can improve the carrier collection efficiency of the first doped semiconductor layer, further reduce the carrier recombination rate, and is beneficial to improving the conversion efficiency of the back contact battery. In addition, it can also make the surface of the doping region facing away from the semiconductor substrate have a relatively high doping concentration, which is beneficial to increasing the leakage current between the doping region and the second doped semiconductor layer, and further reducing the hot spot risk of the back contact battery.

[0036] As a possible implementation solution, 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 within 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 within 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] In the case of adopting the above technical solution, there are various examples of the setting positions of the edges of the second doped semiconductor layer extending from the second region and the first transparent conductive layer extending from the second region. This is beneficial to reducing the manufacturing process difficulty, and 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 actual application scenarios (for example, 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 within the third region, the leakage current between the first doped semiconductor layer, the doping region and the second doped semiconductor layer is relatively small. And 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, 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 beneficial to increase the leakage current between the first doped semiconductor layer, the doping region and the second doped semiconductor layer). Furthermore, the control of the leakage current magnitude between the first doped semiconductor layer, the doping region and the second doped semiconductor layer can be realized, and the balanced regulation of the conversion efficiency and the hot spot risk of the back contact battery can be achieved, thereby improving the working performance of the back contact battery.

[0038] As a possible implementation solution, when both 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, the back contact battery further includes an insulating layer disposed between the first doped semiconductor layer and the second doped semiconductor layer located in the first region.

[0039] In the case of adopting the above technical solution, the insulating layer is disposed between the first doped semiconductor layer and the second doped semiconductor layer located in the first region, which can electrically insulate the two, facilitate controlling the size of the leakage contact area, and enable the back contact battery to have a high conversion efficiency.

[0040] As a possible implementation solution, the back contact battery further includes a second transparent conductive layer covering the first doped semiconductor layer. The second transparent conductive layer and the first transparent conductive layer are physically insulated. Moreover, when the edges of both the second doped semiconductor layer extending from the second region and the first transparent conductive layer extending from the second region are located within the first region, a through insulating groove is provided in the second doped semiconductor layer located in the first region, and the insulating groove divides 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] In the case of adopting the above technical solution, 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. Additionally, when the edges of both the second doped semiconductor layer extending from the second region and the first transparent conductive layer extending from the second region are located within the first region, it can at least result in a large leakage contact area between the second doped semiconductor layer and the doping region, reducing the hot spot risk of the back contact battery. Also, a through insulating groove is provided in the second doped semiconductor layer located in the first region to ensure physical insulation between the second transparent conductive layer and the first transparent conductive layer and prevent short - circuit. The second transparent conductive layer also extends onto the first doped portion far from the second region, ensuring that the second transparent conductive layer has a large coverage area on the first doped semiconductor layer, facilitating the collection and conduction of carriers, and further improving the conversion efficiency of the back contact battery.

[0042] In a second aspect, the present invention provides a photovoltaic module, which includes the back contact battery provided in the first aspect and its various implementation manners above.

[0043] The beneficial effects of the second aspect and its various implementation manners in the present invention can refer to the analysis of the beneficial effects in the first aspect and its various implementation manners, and will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings described herein are used to provide a further understanding of the present invention and form a part of the present invention. The schematic 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 is a schematic longitudinal sectional view of the structure of the back-contact battery provided by an embodiment of the present invention Figure 1 ;

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

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

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

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

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

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

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

[0053] Figure 9 is a schematic longitudinal sectional view of the structure of the back-contact battery provided by an embodiment of the present invention Figure 9 ;

[0054] Figure 10 is a schematic longitudinal sectional view of the structure of the back-contact battery provided by an embodiment of the present invention Figure 10 ;

[0055] Figure 11 is a schematic longitudinal sectional view of the structure of the back-contact battery provided by an embodiment of the present invention Figure 10 One;

[0056] Figure 12 is a schematic longitudinal sectional view of the structure of the back-contact battery provided by an embodiment of the present inventionFigure 10 II;

[0057] Figure 13 Longitudinal sectional schematic view of the structure of the back contact battery provided by the embodiment of the present invention Figure 10 III;

[0058] Figure 14 Longitudinal sectional schematic view of the structure of the back contact battery provided by the embodiment of the present invention Figure 10 IV;

[0059] Figure 15 Longitudinal sectional schematic view of the structure of the back contact battery provided by the embodiment of the present invention Figure 10 V.

[0060] Reference 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 doping portion, 26 is a second doping portion. Detailed implementation manners

[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 merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0062] Various schematic structural diagrams according to embodiments of the present invention are shown in the accompanying drawings. These figures are not drawn to scale, where certain details are enlarged for clearer expression and certain details may be omitted. The shapes of various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary and may actually deviate due to manufacturing tolerances or technical limitations. Those skilled in the art can additionally design regions / layers with different shapes, sizes, and relative positions according to actual requirements.

[0063] In the context of the present invention, when a layer / component is referred to as being "on" another layer / component, the layer / component can be directly on the other layer / component, or there can be intermediate layers / components therebetween. Additionally, if a layer / component is "on" another layer / component in one orientation, then when the orientation is reversed, the layer / component can be "under" the other layer / component. In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention will be 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 only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more, unless otherwise specifically defined. The meaning of "several" is one or more, unless otherwise specifically defined.

[0065] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "mounted", "connected" and "coupled" 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, an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, 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. As Figure 1As shown, the back-contact battery 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 opposite first and second surfaces. The first surface includes alternately spaced first regions 16 and second regions 17, and a third region 18 located between the first regions 16 and the second regions 17. The first doped semiconductor layer 12 is disposed on the first regions 16. The doping element in the first doped semiconductor layer 12 is a first doping element. Doped regions 13 are disposed in the first regions 16 and the third region 18 of the semiconductor substrate 11. The doping concentration of the first doping element in the doped regions 13 is greater than the doping concentration of the first doping element in the second regions 17 of the semiconductor substrate 11. The second doped semiconductor layer 14 is disposed on the second regions 17 and extends to cover at least a portion of the doped regions 13. The second doped semiconductor layer 14 has a conductive type 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 doped regions 13. The first transparent conductive layer 15 covers the second doped semiconductor layer 14 located in the second regions 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 regions 17.

[0067] In the case of adopting the above technical solution, when the back-contact battery is in a working state, the first doped semiconductor layer and the second doped semiconductor layer with opposite conductive types can effectively shunt and collect carriers, which is beneficial to the formation of photocurrent. The first transparent conductive layer covering the second doped semiconductor layer has high conductivity and can timely export the carriers collected by the second doped semiconductor layer, reduce the carrier recombination rate, and is beneficial to improving the conversion efficiency of the back-contact battery. Secondly, as Figure 1As shown in the figure, the back contact battery further includes doping regions 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. Moreover, 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 relatively high, and the doping element in the first doped semiconductor layer 12 is the first doping element. Therefore, the doping region 13 and the first doped semiconductor layer 12 have the same conduction type, and the doping region 13 and the second doped semiconductor layer 14 have opposite conduction types. 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 part 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 facilitate improving the conversion efficiency of the back contact battery, but also be electrically connected to the doping region 13, and the two can form a built-in diode with a lower reverse breakdown voltage. Moreover, the first transparent conductive layer 15 extending from the second region 17 is covered on the second doped semiconductor layer 14 located in the third region 18. Based on this, when the back contact battery is blocked, the leakage current can pass through the first doped semiconductor layer 12, the doping region 13, and the second doped semiconductor layer 14, then through the first transparent conductive layer 15 to the portion extending from the second region 17 to cover above the doping region 13, and finally be led out through the electrode in contact with the portion of the second region 17 corresponding to the first transparent conductive layer 15, reducing the hot spot risk of the back contact battery. Among them, from the above content, it can be seen that the leakage current needs to be conducted through the doping region 13 disposed in the semiconductor substrate 11 between the first doped semiconductor layer 12 and the second doped semiconductor layer 14. Compared with the transmission of the doped semiconductor layer, the lateral conduction ability 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 blocked, reduces the transmission loss of the 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 doping region 13 and the second doped semiconductor layer 14 with opposite conduction types, but also needs to flow through the high-low junction formed by the doping region 13 and the first doped semiconductor layer 12 with the same conduction type. Compared with the solution where the leakage current only flows through the PN junction, during the process of the back contact battery provided by the embodiment of the present invention being 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 magnitude of the reverse leakage current, reducing the carrier recombination loss of the back contact battery, balancing the hot spot risk and the conversion efficiency of the back contact battery, and improving the working performance of the back contact battery.

[0068] In the actual application process, the embodiments of the present invention do not specifically limit the material and conduction type of the semiconductor substrate. Exemplarily, the above-mentioned semiconductor substrate may be a silicon substrate. Alternatively, the above-mentioned semiconductor substrate may also be a substrate made of any semiconductor material such as a silicon-germanium substrate, a germanium substrate, or a gallium arsenide substrate. Secondly, the above-mentioned semiconductor substrate may be an N-type semiconductor substrate or a P-type semiconductor substrate.

[0069] Secondly, the above-mentioned semiconductor substrate includes opposite first and second surfaces. 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 disposed 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 a partial region of the second doped semiconductor layer included in the back-contact battery is disposed 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 ranges of the first region and the second region on the first surface are determined, the range of the third region is also determined. 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 at this time, 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 at this time, 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 of the hot spot risk and the 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 of the first region and the second region, the width of the third region can be greater than or equal to 1 nm and less than or equal to 2 μm. For example, the width of the third region can 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 obstacles such as dust in the installation environment of the back contact battery, the width of the above-mentioned third region can be set within a smaller range, so that the area of the doped region exposed in the third region is smaller, which is beneficial 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; while when there are more obstacles such as dust in the installation environment of the back contact battery, the width of the above-mentioned third region can be set within a larger range, so that the area of the doped region exposed on the surface of the third region is larger, which is beneficial 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 the leakage current size between the doped region and the second doped semiconductor layer can be regulated, the applicability of the back contact battery in different application scenarios can be improved, and at the same time, it is beneficial to realize the balanced regulation of the conversion efficiency and the hot spot risk of the back contact battery, and improve the working performance of the back contact battery.

[0072] In terms of surface topography, as Figure 1 shown, the first surface and the second surface of the semiconductor substrate 11 can be flat surfaces. Alternatively, as Figure 2 shown, the second surface of the semiconductor substrate 11 can also be a textured 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 on the first surface can also be a textured 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 beneficial to reducing the transmission loss.

[0073] Secondly, as Figure 1 shown, on one side of the first surface of the semiconductor substrate 11, the surface of the second region 17 can be flush with the surface of the third region 18. At this time, the part of the second doped semiconductor layer 14 extending from the second region 17 will only be in electrical contact with the surface of the region of the doped region 13 on the surface of the third region 18. Alternatively, as Figure 3As shown, the surface of the second region 17 may 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 within the groove structure 19. At this time, at least a portion of the region of the doping region 13 near the sidewall of the second region 17 may be exposed through the groove structure 19. In this case, when the second doped semiconductor layer 14 extends from the bottom surface 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 be electrically connected to the doping region 13 not only in the thickness direction of the semiconductor substrate 11 at the surface of the third region 18, but also at at least a portion of the sidewall of the groove structure 19, which is beneficial to increasing the leakage contact area and the leakage current magnitude between the second doped semiconductor layer 14 and the doping region 13, and further reducing the hot spot risk of the back contact battery. At the same time, in the actual manufacturing process, if the doping region 13 is formed by an inward diffusion method when forming the first doped semiconductor layer 12, forming the groove structure 19 in the second region 17 can also remove at least a portion of the region of the doping region 13 formed in the second region 17 when forming the entire first doped semiconductor layer 12, reducing the carrier recombination between the doping region 13 and the second doped semiconductor layer 14 at the second region 17, which is beneficial to improving the conversion efficiency of the back contact battery.

[0074] Among them, as Figure 3 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, in the thickness direction of the semiconductor substrate 11, the depth of the groove structure 19 recessed into the semiconductor substrate 11 relative to the surface of the first region 16 may be greater than the doping depth of the doping region 13. In this case, each part of the sidewall of the doping region 13 near the second region 17 in the thickness direction of the semiconductor substrate 11 may be exposed through the groove structure 19, further increasing the leakage contact area and the leakage current magnitude 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 doping region 13 is formed by an inward diffusion method when forming the first doped semiconductor layer 12, 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 doping region 13, it indicates that the doping region 13 formed in the second region 17 has been completely removed, reducing the carrier recombination at the second region 17, so that the second doped semiconductor layer 14 located in the second region 17 has a high 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 doped region. As described above, the recessed depth of the groove structure not only affects the area that can be exposed on the sidewall of the doped region close to the second region, thereby affecting the hot spot risk and conversion efficiency of the back contact cell. Moreover, when the doped region is formed by an inward diffusion method during the formation of the first doped semiconductor layer, the recessed depth of the groove structure also affects 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 cell. Based on this, the specific recessed depth of the groove structure can be determined according to the doping depth of the doped region in the actual application scenario and the requirements for the hot spot risk and conversion efficiency of the back contact cell, and no specific limitation is made 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, when the height difference between the bottom surface of the groove structure and the surface of the third region is within the above range, it is beneficial to prevent the area exposed by the sidewall of the doped region close to the second region through the sidewall of the groove structure from being small due to the small recessed depth of the groove structure, which is conducive to a relatively large leakage contact area between the second doped semiconductor layer and the doped region at the sidewall of the groove structure, reducing the hot spot risk; secondly, if the doped region is formed by an inward diffusion method during the formation of the first doped semiconductor layer, it can also prevent the removal amount corresponding to the formation of the doped region in the second region from being small due to the small height difference, further reducing the carrier recombination between the doped region and the second doped semiconductor layer at the second region, which is beneficial to improving the conversion efficiency of the back contact cell. In addition, it can also be beneficial to prevent the recessed depth of the groove structure from being large due to the large height difference, which is conducive to a relatively large light absorption depth of the part of the semiconductor substrate corresponding to the second region, further improving the conversion efficiency of the back contact cell.

[0077] In addition, as Figure 3 shown, when a groove structure 19 is formed in the second region 17, the sidewall of the groove structure 19 can also be perpendicular to the surface of the third region 18; at this time, the area of the side surface of the doped region 13 close to the second region 17 exposed through the vertical sidewall of the groove structure 19 is relatively small, which is beneficial to controlling the magnitude of the leakage current. Alternatively, as Figure 4As shown, the sidewall of the groove structure 19 can also be inclined with respect to the surface of the third region 18, and the width of the notch of the groove structure 19 is greater than the width of the bottom of the groove. In this case, when other factors are the same, compared with the sidewall of the groove structure 19 being perpendicular to the surface of the third region 18, when the sidewall of the groove structure 19 is inclined with respect to the surface of the third region 18, the area of the side of the doping region 13 close to the second region 17 exposed through the inclined sidewall of the groove structure 19 is larger, which is beneficial to further increasing the leakage contact area and the leakage current magnitude between the second doped semiconductor layer 14 and the doping region 13. In addition, when the sidewall of the groove structure 19 is inclined with respect to the surface of the third region 18 and the width of the notch of the groove structure 19 is greater than the width of the bottom of the groove, the degree of change in the height of the inclined sidewall of the groove structure 19 is more gentle, which is beneficial to the coating of the second doped semiconductor layer 14 on the sidewall of the groove structure 19, improving the electrical connection performance between the portion of the second doped semiconductor layer 14 covering the sidewall of the groove structure 19 and the doping region 13, further reducing the hot spot risk of the back contact battery, and at the same time being beneficial to improving the passivation effect of the second doped semiconductor layer 14 on the sidewall of the groove structure 19 and improving the conversion efficiency of the back contact battery.

[0078] Among them, when the sidewall of the groove structure is inclined with respect to the surface of the third region, the inclination angle of the sidewall of the groove structure with respect to the surface 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.

[0079] Regarding the surface heights of the first region and the third region in the first surface, as Figure 4 shown, the surface of the third region 18 and the surface of the first region 16 can be flush. Or, as Figure 5As shown, the surface of the third region 18 can 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, on 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 structure 19, which is beneficial to the coating of the second doped semiconductor layer 14 on the sidewalls of the groove structure 19 and the surface of the third region 18, improve the electrical connection performance between the second doped semiconductor layer 14 and the doping region 13, further reduce 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 14 on the sidewalls of the groove structure 19 and the surface of the third region 18, and improve the conversion efficiency of the back contact battery. In addition, in the actual manufacturing process, if the doping region 13 is formed by an internal diffusion method 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 magnitude 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 recessed into the semiconductor substrate 11 relative to the surface of the first region 16 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 large 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 high anti-burning ability.

[0080] As for the specific recessed depth of the surface of the third region relative to the surface of the first region recessed into the semiconductor substrate, it can be determined according to the requirements for the doping concentration of the doping region at the surface of the third region, as well as the hot spot risk and conversion efficiency of the back contact battery in the actual application scenario, 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 can be greater than or equal to 10 nm and less than or equal to 2 μm. The height difference between the surface of the third region and the surface of the first region can be 10 nm, 50 nm, 100 nm, 300 nm, 500 nm, 800 nm, 1 μm, 1.2 μm, 1.4 μm, 1.5 μm, 1.8 μm, 2 μm, 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 is possible to prevent the height difference between the surface of the third region and the bottom surface of the groove structure from being large due to the small height difference, resulting in poor formation quality of the second doped semiconductor layer at the sidewall of the groove structure and the surface of the third region, improve the electrical connection performance between the second doped semiconductor layer and the doped region, further reduce 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 sidewall of the groove structure and the surface of the third region. In addition, it is possible to prevent the doping depth of the doped region at the third region from being small due to the large height difference, and reduce 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 the internal diffusion method when forming the first doped semiconductor layer, 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 of the doped region at the surface of the third region, thereby affecting the magnitude of the leakage current between the doped region and the second doped semiconductor layer at the third region. Based on this, according to the requirements of different actual application scenarios, if there are fewer dust and other blocking objects in the installation environment of the back contact battery, the above height difference can be set within a larger range, so that the doping concentration of the doped region at the surface of the third region is smaller, which is beneficial to reducing the magnitude of the leakage current between the doped region and the second doped semiconductor layer, and is conducive to the back contact battery having a higher conversion efficiency; when there are more dust and other blocking objects in the installation environment of the back contact battery, the above height difference can be set within a smaller range, so that the doping concentration of the doped region at the surface of the third region is larger, which is beneficial to increasing the magnitude of the leakage current between the doped region and the second doped semiconductor layer, and further improving the anti-burning ability of the back contact battery. In summary, by controlling the magnitude of the height difference between the surface of the third region and the surface of the first region, the magnitude of the leakage current between the doped region and the second doped semiconductor layer can be regulated, and the applicability of the back contact battery in different application scenarios can be improved.

[0082] In terms of doping, the doped region is doped with a first doping element. The type of the first doping element can be one kind, for example, the first doping element can be phosphorus; or, the type of the first doping element can also be multiple kinds with the same conduction type, for example, the first doping element can include phosphorus and arsenic. The type of the first doping element in the doped region can be the same as or different from the type of the first doping element in the first doped semiconductor layer. For example: when the conduction types of the first doped semiconductor layer and the doped region are N-type, the first doping elements in the first doped semiconductor layer and the doped region can both be phosphorus. Another example: when the conduction types of the first doped semiconductor layer and the doped region are P-type, the first doping elements in the first doped semiconductor layer and the doped region can both be boron. Still another example: when the conduction types of the first doped semiconductor layer and the doped region are N-type, the first doping element in the first doped semiconductor layer can be phosphorus, while the first doping elements in the doped region can all be arsenic. It can be understood that if in the actual manufacturing process, the first doping element in the doped region diffuses from the first doped semiconductor layer into the doped 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 doped region.

[0083] In addition, in the actual application process, the doping concentration of the first doping element on the side of the doped 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 ability of the first doped silicon layer. Moreover, it is also beneficial to form a high-low junction between the first doped semiconductor layer and the doped region. The existence of this high-low junction is conducive to controlling the magnitude of the reverse leakage current, making the back contact battery have a higher conversion efficiency. At the same time, when the doping concentration of the first doping element on the side of the doped region close to the first doped 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 doped region can also be formed by an internal diffusion method when forming the first doped semiconductor layer, without the need to adopt other manufacturing processes additionally for forming the doped 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 doped 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] Exemplarily, the doping concentration of the first doping element in the doped region can 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 doped region can 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, a high-low junction can be formed between different regions of the doping layer along the direction from the second surface to the first surface, and the built-in electric field of this high-low junction is consistent with the induction direction of the first doped semiconductor layer, which can improve the carrier collection efficiency of the first doped semiconductor layer, further reduce the carrier recombination rate, and is beneficial to improving the conversion efficiency of the back-contact battery. In addition, it is also possible to make the surface of the doping region on the side away from the semiconductor substrate have a relatively high doping concentration, which is beneficial to increasing the magnitude of the leakage current between the doping region and the second doped semiconductor layer, and further reducing the hot spot risk of 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 requirements of the doping region, and no specific limitation is made here.

[0085] As for the doping concentration of the first doping element in the part of the doping region located in the third region, it can be understood that the doping concentration of the first doping element corresponding to the surface of the third region of 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 corresponding to the surface of the third region of the doping region, the relatively lower the conductive performance of the doping region, resulting in a relatively high transmission loss of the reverse leakage current, but at this time the conversion efficiency of the back-contact battery is relatively high. And the larger the doping concentration of the first doping element corresponding to the surface of the third region of the doping region, the relatively higher the conductive performance of the doping region, which is beneficial to the transmission of the reverse leakage current, and at this time the hot spot risk of the back-contact battery is relatively low. In addition, as Figure 5As shown, in the actual manufacturing process, when the first doping element in the doping region 13 diffuses from the first doped semiconductor layer 12 into the doping region 13, whether there is a groove structure 19 in the second region 17 and the size of the recess 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 recess 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 can 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, beneficial to controlling the magnitude of the leakage current between the doping region and the second doped semiconductor layer, and thus improving the conversion efficiency of the back contact battery. Or, the doping concentration of the first doping element at the surface of the third region corresponding to the doping region can 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] Exemplarily, the doping concentration of the first doping element at the surface of the third region corresponding to the doping region can 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 third region corresponding to the doping region can 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 fewer obstacles such as dust in the installation environment of the back-contact battery, the doping concentration of the first doping element at the surface of the doping region corresponding to the third region can be set within a relatively small range, so that the conductivity characteristics of the doping region at the surface of the third region are relatively low, which is conducive to reducing the leakage current between the doping region and the second doped semiconductor layer, and is beneficial to the back-contact battery having a high conversion efficiency; while when there are more obstacles such as dust in the installation environment of the back-contact battery, the doping concentration of the first doping element at the surface of the doping region corresponding to the third region can be set within a relatively small range, so that the conductivity characteristics of the doping region at the surface of the third region are relatively high, which is conducive to increasing the leakage current between 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 by controlling the doping concentration of the first doping element at the surface of the doping region corresponding to the third region, the leakage current between the doping region and the second doped semiconductor layer can be regulated, the applicability of the back-contact battery in different application scenarios can be improved, and at the same time, it is beneficial to achieve the balanced regulation of the conversion efficiency and hot spot risk of the back-contact battery, and improve the working performance of the back-contact battery.

[0088] Regarding 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 can be one kind, such as the second doping element can be boron; or, the type of the second doping element can be multiple kinds with the same conductivity type, such as the second doping element can 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 can be the same. In this case, there is no internal diffusion doping region in the second region of the semiconductor substrate with the same conductivity type as the second doped silicon layer, which can prevent the above-mentioned doping region from making electrical contact with the internal diffusion doping region with the opposite conductivity type and resulting in too high carrier recombination rate, and is beneficial to the back-contact battery having a high conversion efficiency. At the same time, it can also prevent the part of the second doped semiconductor layer covering the third region from forming an internal diffusion doping region, which may lead to a relatively low doping concentration of the above-mentioned doping region at the third region, and is beneficial to the back-contact battery having a high anti-burning ability.

[0089] For the above-mentioned first doped semiconductor layer, in terms of the conductivity type, the present invention embodiment does not make specific limitations on 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, and at this time 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, and at this time 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 one of semiconductor materials such as silicon, silicon germanium, germanium, or gallium arsenide. In terms of the arrangement form of substances, the crystal phase of the first doped semiconductor layer may be amorphous, microcrystalline, nanocrystalline, single crystal, or polycrystalline, etc.

[0091] In terms of the formation position, as Figure 1 shown, the first doped semiconductor layer 12 may be directly disposed on the first region 16. Alternatively, as Figure 5 shown, the above back contact battery may further 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 achieve selective collection of carriers, reduce the carrier recombination rate of the first region 16 on 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 requirements, and no specific limitation is made 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] Regarding 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 diffuses from the first doped semiconductor layer into the doping region, the doping concentration of the first doping element in the first doped semiconductor layer will also affect the doping concentration of the first doping element in the doping region. Therefore, it can be determined according to 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 one of semiconductor materials such as silicon, silicon germanium, germanium, or gallium arsenide. In terms of the arrangement form of substances, the crystal phase of the second doped semiconductor layer may be amorphous, microcrystalline, nanocrystalline, single crystal, or polycrystalline, etc. 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 no specific limitation is made here.

[0094] In terms of doping, 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 affects the carrier recombination loss of the back contact cell and the reverse breakdown voltage of the back contact cell when it is shaded. Based on this, the doping concentration of the second doping element in the second doped semiconductor layer can be determined according to the requirements of 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, as Figure 1 shown, the above-mentioned second doped semiconductor layer 14 can be directly disposed in the second region 17 and extend to cover at least a part of the doped region 13. Or, as Figure 5 shown, the above-mentioned back contact cell may further include a second interface passivation layer 21, and the second interface passivation layer 21 is located between the second region 17 on the first surface and the second doped semiconductor layer 14 and extends to between the second doped semiconductor layer 14 and the doped region 13. In this case, the passivation contact structure formed by the second interface passivation layer 21 and the part of the second doped semiconductor layer 14 located on the second region 17 can achieve selective collection of carriers and reduce the carrier recombination rate of the second region 17 on 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 requirements, and no specific limitation is made 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 layer 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 form a heterojunction contact structure, and the heterojunction contact structure has a better passivation effect than the tunneling passivation contact structure, which can further reduce the carrier recombination rate at the interface between the semiconductor substrate and the second interface passivation layer, and is beneficial to improving the photoelectric conversion efficiency of the back contact cell. In addition, when the second interface passivation layer is an intrinsic semiconductor layer passivation layer, it indicates that the doping element in the second doped semiconductor layer does not diffuse 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 that the doping concentration of the second doping element in each part of the second region of the semiconductor substrate is the same along the direction from the first surface to the second surface described above, and will not be elaborated here.

[0097] In terms of the formation range, as Figure 5 and Figure 6As shown, the edge of the second doped semiconductor layer 14 extending from the second region 17 may be located within the third region 18. At this time, within the third region 18, the second doped semiconductor layer 14 may cover only a partial region of the doped region 13, or may cover the entire region of the doped region 13.

[0098] Alternatively, as Figure 7 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, within 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. The extension width of the second doped semiconductor layer 14 within the first region 16 may be set according to actual requirements and is not specifically limited here. Alternatively, as Figure 8 shown, the back contact battery may further 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, and can electrically insulate the two, which is conducive to controlling the size of the leakage contact area and enabling the back contact battery to have a high conversion efficiency. The material and thickness of the insulating layer 22 may be set according to actual requirements 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 embodiments of the present invention do 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, indium tin oxide, indium tungsten oxide, indium molybdenum oxide, indium cerium oxide, and indium hydroxide.

[0100] In terms of the formation range, the formation range of the first transparent conductive layer may 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] Exemplarily, as Figure 5 and Figure 6 shown, in the case where the edge of the second doped semiconductor layer 14 extending from the second region 17 is located within the third region 18, the edge of the first transparent conductive layer 15 extending from the second region 17 is also located within the third region 18. At this time, within the third region 18, 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 indented inward relative to the edge of the second doped semiconductor layer 14 in the direction from the first region 16 to the second region 17, and the indented distance may be determined according to the requirements for the hot spot risk and conversion efficiency of the back contact battery in the actual scenario and is not specifically limited here.

[0102] Exemplarily, as Figure 7 , Figure 8 and Figure 9 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 within the third region 18. At this time, in the third region 18, the first transparent conductive layer 15 may cover only a partial region of the doped region 13, or may cover the entire region of the doped region 13.

[0103] Alternatively, as Figure 10 and Figure 11 shown, when 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; alternatively, the edge of the first transparent conductive layer 15 may also be indented inward relative to the edge of the second doped semiconductor layer 14 in the direction from the first region 16 to the third region 18, and the indented distance may be determined according to the requirements for the hot spot risk and conversion efficiency of the back contact battery in the actual scenario, and no specific limitation is made here. Among them, as Figure 12 shown, when both 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 may further 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 high conversion efficiency; at this time, the extension widths of the second doped semiconductor layer 14 and the first transparent conductive layer 15 on the first region 16 may be determined according to the actual manufacturing requirements, and no specific limitation is made here.

[0104] It should be noted that, as Figures 5 to 12As shown, there are various examples of the setting positions of 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. While facilitating the reduction of the manufacturing process difficulty, the extension coverage ranges of the second doped semiconductor layer 14 and the first transparent conductive layer 15 can also be determined according to the requirements of different actual 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 within 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. And 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, 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, 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 realizing the control of the magnitude of the leakage current between the first doped semiconductor layer 12, the doped region 13, and the second doped semiconductor layer 14, achieving 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.

[0105] In addition, the first doped semiconductor layer can be in ohmic contact with the corresponding electrode directly; or, as Figure 13 shown, the back-contact battery may further 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 transport 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, which will not be elaborated here. In the actual application process, the materials of the first transparent conductive layer 15 and the second transparent conductive layer 23 can be the same or different. The first transparent conductive layer 15 and the second transparent conductive layer 23 can be integrally continuous, that is, they adopt the same manufacturing process and are formed simultaneously; or, the first transparent conductive layer 15 and the second transparent conductive layer 23 can also be formed separately in different operation steps.

[0106] Among them, in the case where 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 within the first region, and the back-contact battery further includes a second transparent conductive layer, as Figure 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 close to 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. Or, as Figure 14 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 edge of the second transparent conductive layer 23 close to the third region 18 and the first transparent conductive layer 15 are spaced apart along the arrangement direction of the first region 16 and the second region 17. Or, as Figure 15 shown, a through insulating groove 24 is provided in the second doped semiconductor layer 14 located in the first region 16. The insulating groove 24 divides 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 should be noted 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, it can at least make the leakage contact area between the second doped semiconductor layer and the doped region larger, reducing the hot spot risk of the back contact battery. Moreover, a through insulating groove is provided in the second doped semiconductor layer located in the first region to ensure physical insulation between the second transparent conductive layer and the first transparent conductive layer and prevent short circuit. The second transparent conductive layer also extends onto the first doped portion far from the second region to ensure that the second transparent conductive layer has a large coverage area on the first doped semiconductor layer, which is beneficial to the collection and conduction of carriers, 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 will not be specifically limited here.

[0108] In a second aspect, an embodiment of the present invention provides a photovoltaic module, which includes the back contact battery provided in the first aspect and its various implementation manners above.

[0109] For the beneficial effects of the second aspect and its various implementation manners in the embodiments of the present invention, reference can be made to the analysis of the beneficial effects in the first aspect and its various implementation manners, which will not be elaborated here.

[0110] In the above description, technical details such as the composition and etching of each layer are not elaborated in detail. However, those skilled in the art should understand that various technical means can be used to form layers, regions, etc. of the required shapes. Additionally, to form the same structure, those skilled in the art can also design methods that are not exactly the same as the methods described above. Moreover, although the embodiments are described separately above, this does not mean that the measures in each embodiment cannot be advantageously combined.

[0111] The embodiments of the present invention have been described above. However, these embodiments are merely for clearer illustration and not for limiting 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, those skilled in the art can make various substitutions and modifications, and these substitutions and modifications should all fall within the scope of the present invention.

Claims

1. A back-contact battery, characterized in that, Comprising: A semiconductor substrate including opposite first and second surfaces; the first surface includes alternately and spaced-apart first regions and second regions, and a third region located between the first regions and the second regions; A first doped semiconductor layer disposed on the first regions of the semiconductor substrate; the doping element in the first doped semiconductor layer is a first doping element; A doped region disposed within the first regions and the third region of the semiconductor substrate; Along the thickness direction of the semiconductor substrate, the doped region is disposed close to the first surface of the semiconductor substrate; the doping concentration of the first doping element in the doped region is greater than the doping concentration of the first doping element within the second region of the semiconductor substrate; within the first regions, the first doped semiconductor layer is located on the side of the doped region away from the semiconductor substrate; A second doped semiconductor layer disposed on the second regions of the semiconductor substrate and extending to cover at least a portion of the doped region; the second doped semiconductor layer has a conductivity type opposite to that of the first doped semiconductor layer; within the third region, the second doped semiconductor layer is electrically connected to the doped region; A first transparent conductive layer covering the second doped semiconductor layer located in the second regions and the second doped semiconductor layer located in the third region is covered with the first transparent conductive layer extending from the second regions.

2. The back-contact battery according to claim 1, characterized in that, The surface of the second regions 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 regions is located within 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 regions is greater than the doping depth of the doped region; And / or, the sidewalls of the groove structure are inclined relative to the surface of the third region, and the width of the notch of the groove structure is greater than the width of the bottom of the groove; And / or, 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.

4. The back-contact battery 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 regions, and the recessed depth is less than the depth of the doped region.

5. The back-contact battery according to claim 4, wherein, The height difference between the surface of the third region and the surface of the first regions 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 doped 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 battery according to claim 2, wherein Along the distribution direction of the alternate spacing of the first regions and the second regions, the 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 battery according to claim 1, characterized in that, The doping concentration of the first doping element at the surface of the third region corresponding to the doped region is less than the doping concentration of the first doping element at the surface of the first regions corresponding to the doped region.

8. The back-contact battery 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 regions of the semiconductor substrate is the same.

9. The back-contact battery according to claim 1, characterized in that, The back contact battery includes 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 battery 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 battery 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 battery according to claim 1, characterized in that, The doping concentration of the first doping element on the side of the doped region close to the first doped semiconductor layer is less than or equal to the doping concentration of the first doping element in the first doped 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 doped region gradually increases along the direction from the second surface to the first surface.

12. The back-contact battery according to claim 1, characterized in that, 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 within the third region; or, the second doped semiconductor layer extending from the second region continues to extend into the first region; the edge of the first transparent conductive layer extending from the second region is located within the third region; or, 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 battery 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 battery further includes an insulating layer, and the insulating layer is disposed between the first doped semiconductor layer and the second doped semiconductor layer located in the first region.

14. The back contact battery according to claim 12, characterized in that, The back contact battery further includes a second transparent conductive layer, and the second transparent conductive layer covers the first doped semiconductor layer; the second transparent conductive layer and the first transparent conductive layer are physically insulated; In the case where 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 within the first region, an insulating groove is provided in the second doped semiconductor layer located in the first region, and the insulating groove divides 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 the back contact battery according to any one of claims 1 to 14.

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