A back-contact battery, a manufacturing method thereof, and a photovoltaic module

Abstract

The present invention discloses a back-contact battery, a manufacturing method thereof, and a photovoltaic module, relating to the technical field of photovoltaics, which are used to enable the back-contact battery to have a lower hot-spot risk and improve the working reliability of the back-contact battery; meanwhile, enable the back-contact battery to have a higher working efficiency in the forward voltage region. The back-contact battery includes a semiconductor substrate, a first doped semiconductor portion, a second doped semiconductor portion, and a transparent conductive layer. In the reverse leakage region, the portion of the transparent conductive layer extending from the second region into the overlapping region is a first transparent conductive portion, and the first transparent conductive portion is electrically connected to the first doped semiconductor portion through the second doped semiconductor portion. The width of the above-mentioned first transparent conductive portion in the first direction is W1, the width of the overlapping region in the first direction is W2, and the ratio of W1 to W2 is greater than or equal to 10% and less than or equal to 90%.

Description

[0001] This application claims the priority of a Chinese patent titled "A Back-Contact Battery and Its Manufacturing Method, Photovoltaic Module" with an application number of 202410788218.1 and filed with the Chinese Patent Office on June 18, 2024. The entire content thereof is incorporated herein by reference. Technical Field

[0002] The present invention relates to the technical field of photovoltaic modules, and particularly to a back-contact battery and its manufacturing method, and a photovoltaic module. Background Art

[0003] A back-contact battery refers to a solar battery in which the light-facing surface of the battery cell has no electrodes, and the positive and negative electrodes are both disposed on the backlight side of the battery cell, thereby reducing the shielding of the electrodes on the battery cell, increasing the short-circuit current of the battery cell, and improving the energy conversion efficiency of the battery cell.

[0004] During the actual use of a back-contact battery, there may be obstacles such as bird droppings, leaves, and dust falling on the back-contact battery. After the battery cell is blocked, the temperature will rise and a hot spot effect will be generated. 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 battery. In severe cases, it may pose a fire risk. Summary of the Invention

[0005] The purpose of the present invention is to provide a back-contact battery and its manufacturing method, and a photovoltaic module.

[0006] To achieve the above object, in a first aspect, the present invention provides a back-contact battery. The back-contact battery includes: a semiconductor substrate, a first doped semiconductor portion, a second doped semiconductor portion, and a transparent conductive layer. The second doped semiconductor portion and the first doped semiconductor portion have opposite conductivity types. The semiconductor substrate includes opposite first and second surfaces. The first surface includes a first region, a second region, and an overlapping region located between the first region and the second region. Moreover, the first region, the overlapping region, and the second region are arranged along a first direction. The first doped semiconductor portion is disposed on the first region and the overlapping region. The second doped semiconductor portion is disposed on the second region and extends to cover the first doped semiconductor portion in the overlapping region. The transparent conductive layer covers the second doped semiconductor portion and the first doped semiconductor portion. An insulating groove is provided in the transparent conductive layer to physically insulate the portion of the transparent conductive layer corresponding to the first region from the portion of the transparent conductive layer corresponding to the second region. Wherein, at least a part of the overlapping region is a reverse leakage region. Moreover, in the reverse leakage region, the portion of the transparent conductive layer extending from the second region into the overlapping region is a first transparent conductive portion, and the first transparent conductive portion is electrically connected to the first doped semiconductor portion through the second doped semiconductor portion. The width of the first transparent conductive portion in the first direction is W1, the width of the overlapping region in the first direction is W2, and the ratio of W1 to W2 is greater than or equal to 10% and less than or equal to 90%.

[0007] Under the above technical solution, when the back-contact battery is in a working state, the first doped semiconductor portion and the second doped semiconductor portion can effectively shunt carriers, which is beneficial to the formation of photocurrent. The transparent conductive layer covering the second doped semiconductor portion and the first doped semiconductor portion has a high conductivity and can timely export the carriers collected by the first doped semiconductor portion and the second doped semiconductor portion, reducing the carrier recombination rate. The second doped semiconductor portion is not only disposed on the second region but also extends to cover the first doped semiconductor portion in the overlapping region. Moreover, at least part of the overlapping region is a reverse leakage region. In this reverse leakage region, the portion of the transparent conductive layer extending from the second region into the overlapping region (i.e., the first transparent conductive portion) can be electrically connected to the first doped semiconductor portion with a conductivity type opposite to that of itself through the second doped semiconductor portion. At this time, the overlapping portion of the first doped semiconductor portion and the second doped semiconductor portion forms a built-in diode structure with a low reverse breakdown voltage. When the back-contact battery is blocked, the leakage current passes through the overlapping portion of the first doped semiconductor portion and the second doped semiconductor portion, then through the first transparent conductive portion and is exported through the electrode in contact therewith. It should be noted that in the reverse leakage region, the above-mentioned first transparent conductive portion is electrically connected to the first doped semiconductor portion with a conductivity type opposite to that of itself through the second doped semiconductor portion, and this electrical connection method does not include electrical connection through the semiconductor substrate. It can be understood that the second doped semiconductor portion and the first doped semiconductor portion can be electrically connected through a tunneling mechanism or a thin dielectric layer. Secondly, in the back-contact battery provided by the present invention, the insulating groove provided in the transparent conductive layer can physically insulate the portion of the transparent conductive layer corresponding to the first region from the portion of the transparent conductive layer corresponding to the second region. This physical insulation means non-contact to prevent the back-contact battery from short-circuiting.

[0008] In addition, in the back contact cell provided by the present invention, there is no need to set an insulating layer for separating the first doped semiconductor portion and the second doped semiconductor portion in the portion where they overlap with each other, which is beneficial to simplifying the manufacturing process of the back contact cell while taking advantage of the electrical connection between the two in the reverse leakage region to reduce the risk of hot spots. Moreover, along the first direction, the larger the width of the first transparent conductive portion provided in the reverse leakage region, the smaller the transmission resistance of the leakage current in the first transparent conductive portion, the greater the corresponding reduction in the reverse breakdown voltage, and the leakage loss of the back contact cell in the forward voltage region may be higher. Conversely, along the first direction, the smaller the width of the first transparent conductive portion provided in the reverse leakage region, the larger the transmission resistance of the leakage current in the first transparent conductive portion, the smaller the corresponding reduction in the reverse breakdown voltage, and the leakage loss of the back contact cell in the forward voltage region may be lower. Based on this, during application, the back-contact cell provided by the present invention only needs to adjust the width W1 of the first transparent conductive portion in the first direction and the width W2 of the overlapping region in the first direction to adjust the leakage loss and reverse breakdown voltage. This can reduce the risk of hot spots in the back-contact cell while ensuring higher operating efficiency in the forward voltage region. Furthermore, during the actual manufacturing process, only the selective etching pattern used to form the transparent conductive layer needs to be fine-tuned, without changing other manufacturing processes of the back-contact cell. This improves the compatibility of the back-contact cell provided by the present invention with existing manufacturing processes and reduces the manufacturing difficulty of the back-contact cell provided by the present invention.

[0009] As a possible implementation, the portion of the transparent conductive layer extending from the first region into the overlapping region is the second transparent conductive portion. The width of the second transparent conductive portion in the first direction is W3, and the ratio of W3 to W2 is less than or equal to 80%.

[0010] In the above technical solution, the second transparent conductive portion is the portion of the transparent conductive layer extending from the first region into the overlapping region. Due to the spacing provided by the insulating trench, leakage current is conducted only through the first doped semiconductor portion in the reverse leakage region and then through the second doped semiconductor portion to the first transparent conductive portion of opposite conductivity type. Little or no leakage current is transmitted through the second transparent conductive portion in the reverse leakage region to the first transparent conductive portion of opposite conductivity type. Therefore, the presence of the second transparent conductive portion has little or no effect on the reverse breakdown voltage. Furthermore, the first transparent conductive portion, the second transparent conductive portion, and the insulating trench are all provided in the overlapping region. To separate the portions of the transparent conductive layer corresponding to the first and second regions, it is understood that the width of the insulating trench in the first direction must be greater than or equal to the minimum spacing required to prevent leakage. In the above case, when the width of the second transparent conductive portion in the first direction is W3 and the ratio of W3 to W2 is less than or equal to 80%, the width of the second transparent conductive portion in the first direction can be adjusted to facilitate the adjustment of the width of the first transparent conductive portion in the first direction, further facilitating a balance between the reverse breakdown voltage and operating efficiency of the back-contact battery.

[0011] As a possible implementation scheme, the reverse leakage region is continuously distributed along the second direction, and the second direction intersects with the first direction. In this case, the portion of the transparent conductive layer extending from the second region into the overlapping region (i.e., the first transparent conductive portion) can be continuously distributed along the second direction, so that the pattern for selectively etching the entire layer of transparent conductive material (the transparent conductive material is used to manufacture the transparent conductive layer) disposed on the first doped semiconductor portion and the second doped semiconductor portion (the transparent conductive material is used to manufacture the transparent conductive layer) is relatively simple (only the pattern corresponding to the notch of the insulating groove), which helps to reduce the difficulty of patterning the back contact battery. At the same time, when the reverse leakage region is continuously distributed along the second direction, the leakage path between the first doped semiconductor portion and the second doped semiconductor portion is more evenly distributed, thereby facilitating the uniform distribution of heat generated when the back contact battery is blocked across the entire battery area, further improving the back contact battery's anti-burning capability.

[0012] As a possible implementation solution, when the reverse leakage regions are continuously distributed along the second direction, the ratio of W1 to W2 is greater than or equal to 10% and less than or equal to 70%.

[0013] When the above technical solution is adopted, it can be understood that in the reverse leakage region, the contact area between the first transparent conductive portion and the second doped semiconductor portion is proportional to the reverse breakdown voltage. When the reverse leakage region is continuously distributed along the second direction, the extension length of the first transparent conductive portion along the second direction is fixed. In this case, the reverse breakdown voltage and forward leakage loss can be controlled by adjusting the width of the first transparent conductive portion along the first direction. Based on this, in this case, when the ratio of W1 to W2 is greater than or equal to 10% and less than or equal to 70%, it is beneficial to prevent the reverse breakdown voltage from being reduced due to a small contact area between the first transparent conductive portion and the second doped semiconductor portion due to a small ratio of W1 to W2. In addition, it can also prevent the forward leakage loss from being increased due to a large contact area between the first transparent conductive portion and the second doped semiconductor portion due to a large ratio of W1 to W2, further facilitating a balance between the reverse breakdown voltage and operating efficiency corresponding to the back-contact cell.

[0014] As a possible implementation scheme, the above-mentioned reverse leakage area is intermittently distributed along the second direction, and the second direction intersects with the first direction. Along the second direction, the first transparent conductive portion has a continuous area and a discontinuous area. In this case, another implementation method is provided for the distribution of the first transparent conductive portion along the second direction. At this time, not only can the reverse breakdown voltage and forward leakage loss of the back contact battery be regulated by adjusting the width of the first transparent conductive portion along the first direction, but the reverse breakdown voltage and forward leakage loss of the back contact battery can also be regulated by adjusting the length of the continuous area and the discontinuous area of the first transparent conductive portion along the second direction, thereby improving the applicability of the back contact battery provided by the present invention in different application scenarios.

[0015] As a possible implementation solution, when the reverse leakage region is discontinuously distributed along the second direction, the ratio of the length of the discontinuous region to the length of the continuous region along the second direction is less than or equal to 90%. In this case, when the back contact battery provided by the present invention is installed in an environment with few obstacles such as bird droppings, leaves, or dust, the ratio of the length of the discontinuous region to the length of the continuous region can be set within a relatively large range to increase the proportion of the discontinuous region in the reverse leakage region, thereby facilitating the reduction of the leakage loss of the back contact battery in the forward voltage region and ensuring that the back contact battery has a high working efficiency. When the back contact battery provided by the invention is installed in an environment with many obstacles such as bird droppings, leaves, or dust, the ratio of the length of the discontinuous region to the length of the continuous region can be set within a relatively small range to increase the proportion of the continuous region in the reverse leakage region, thereby facilitating the reduction of the reverse breakdown voltage of the back contact battery and ensuring that the back contact battery has a low hot spot risk. Thus, it can be seen that when the ratio of the length of the discontinuous region to the length of the continuous region along the second direction is less than or equal to 90%, the lengths of the discontinuous region and the continuous region can be set according to different environmental requirements, improving the applicability of the back contact battery provided by the present invention in different actual application scenarios.

[0016] As a possible implementation solution, when the reverse leakage region is discontinuously distributed along the second direction, the ratio of W1 to W2 is greater than or equal to 20% and less than or equal to 90%. Such a setting can improve the applicability of the back contact battery provided by the present invention in different actual application scenarios. Specifically, the application principle of the beneficial effects in this case is similar to the application principle of the beneficial effects when the reverse leakage region is continuously distributed along the second direction and the ratio of W1 to W2 is greater than or equal to 10% and less than or equal to 70%, which will not be elaborated here.

[0017] As a possible implementation solution, when the reverse leakage region is discontinuously distributed along the second direction, the ratio of the width of the continuous region to the length of the continuous region is greater than or equal to 1:500 and less than or equal to 5:1. Such a setting can improve the applicability of the back contact battery provided by the present invention in different actual application scenarios. Specifically, the application principle of the beneficial effects in this case is similar to the application principle of the beneficial effects when the reverse leakage region is continuously distributed along the second direction and the ratio of W1 to W2 is greater than or equal to 10% and less than or equal to 70%, which will not be elaborated here.

[0018] As a possible implementation solution, when the reverse leakage region is discontinuously distributed along the second direction, the part of the transparent conductive layer disposed in the second region is the third transparent conductive part. The part of the third transparent conductive part corresponding to the discontinuous region is provided with a notch.

[0019] In the case of adopting the above technical solution, the second doped semiconductor portion is not only disposed on the second region, but also extends to cover the first doped semiconductor portion on the overlapping region. At this time, the second doped semiconductor portion can be not only located on the side of the first doped semiconductor portion on the overlapping region away from the semiconductor substrate, but also on the side wall of the first doped semiconductor portion on the overlapping region. Moreover, the transparent conductive layer is located on the first doped semiconductor portion and the second doped semiconductor portion. At this time, the transparent conductive layer can contact the second doped semiconductor portion disposed on the side wall of the first doped semiconductor portion on the overlapping region. In this case, when a notch is provided in the portion of the third transparent conductive portion corresponding to the discontinuous region in the portion of the transparent conductive layer disposed in the second region, it can be ensured that the third transparent conductive portion is not electrically connected to the second doped semiconductor portion in the discontinuous region, and it can be ensured that by adjusting the lengths of the discontinuous region and the continuous region of the first transparent conductive portion in the second direction, the contact area between the second doped semiconductor portion and the transparent conductive layer in the reverse leakage region can be effectively adjusted, so as to achieve precise control of the reverse breakdown voltage and the forward leakage loss of the back contact battery. At the same time, in the actual application and manufacturing process, selective etching of the first transparent conductive portion is required to achieve the discontinuous distribution of the reverse leakage region in the second direction. Based on this, when a notch is provided in the portion of the third transparent conductive portion adjacent to the first transparent conductive portion corresponding to the discontinuous region, there is no need to strictly control the etching accuracy to accurately stop the etching of the first transparent conductive portion at the junction of the first transparent conductive portion and the third transparent conductive portion in order to achieve the above selective etching, which is beneficial to reducing the manufacturing difficulty of the back contact battery.

[0020] As a possible implementation solution, the width of the above notch in the first direction is less than or equal to 100 μm.

[0021] In the case of adopting the above technical solution, it can be understood that in the transparent conductive layer, the portion (i.e., the third transparent conductive portion) disposed on the side of the second doped semiconductor portion away from the semiconductor substrate needs to export the carriers collected by the portion of the second doped semiconductor portion corresponding to the second region to the corresponding electrode when the back contact battery is in the working state, and can reduce the contact barrier between the second doped semiconductor portion and the corresponding electrode, and reduce the carrier transmission loss. Based on this, when a notch is provided in the portion of the third transparent conductive portion corresponding to the spacer region, the carriers collected by the portion of the second doped semiconductor portion corresponding to the notch need to be transmitted into the third transparent conductive portion through the adjacent portion. At this time, the transmission loss of the carriers collected by the portion of the second doped semiconductor portion corresponding to the notch is relatively high. In this case, when the width of the notch in the first direction is less than or equal to 100 μm, the range of the notch is relatively small, which is beneficial to controlling the transmission loss of the carriers collected in the second doped semiconductor portion within a certain range while reducing the difficulty of selective etching, and ensuring that the back contact battery has a high photoelectric conversion efficiency.

[0022] As a possible implementation solution, the doping concentration of the dopant in the above-mentioned first doped semiconductor portion and / or second doped semiconductor portion is greater than or equal to 1E19 cm -3 and less than or equal to 5E20 cm -3 .

[0023] In the case of adopting the above technical solution, the doping concentration of the dopant in at least one of the first doped semiconductor portion and the second doped semiconductor portion is within the above range, which can prevent the field passivation effect of the semiconductor substrate on itself from being low due to the low doping concentration of the dopant in the first doped semiconductor portion and / or the second doped semiconductor portion, and ensure that the first side of the back contact battery has a relatively low carrier recombination rate under normal working conditions; at the same time, it is also beneficial to make the first doped semiconductor portion and / or the second doped semiconductor portion have good electrical conductivity, and ensure that the portion of the first doped semiconductor portion and / or the second doped semiconductor portion in the reverse leakage region has a relatively low transfer resistance when the back contact battery is blocked, which is further beneficial to reducing the reverse breakdown voltage of the back contact battery. In addition, it can also prevent the difficulty of doping the intrinsic semiconductor layer used to manufacture the first doped semiconductor portion and / or the second doped semiconductor portion from being high due to the high doping concentration of the dopant in the first doped semiconductor portion and / or the second doped semiconductor portion, which is beneficial to improving the yield of the back contact battery.

[0024] As a possible implementation solution, the thickness of the first doped semiconductor portion is greater than or equal to 50 nm and less than or equal to 200 nm.

[0025] In the case of adopting the above technical solution, when the thickness of the first doped semiconductor portion is within the above range, it can prevent the field passivation effect of the first doped semiconductor portion from being low due to the small layer thickness of the first doped semiconductor portion; it can also prevent the large consumption of consumables for manufacturing the first doped semiconductor portion due to the large thickness of the first doped semiconductor portion, which is beneficial to controlling the manufacturing cost of the back contact battery. In addition, the thickness of the first doped semiconductor portion will affect the docking height between the side surface of the first doped semiconductor portion and the side surface of the second doped semiconductor portion, and further affect the junction area of the PN junction formed between the first doped semiconductor portion and the second doped semiconductor portion in the reverse leakage region. Based on this, when the thickness of the first doped semiconductor portion is within the above range, it can also prevent the large leakage current at the side docking portion of the first doped semiconductor portion and the second doped semiconductor portion due to the large docking height caused by the large thickness of the first doped semiconductor portion, and ensure that the leakage loss and reverse breakdown voltage of the back contact battery can be effectively regulated by adjusting the width W1 of the first transparent conductive portion in the first direction and the width W2 of the overlapping region in the first direction, so that the back contact battery has high working performance and working reliability.

[0026] As a possible implementation solution, the degree of crystallization of the second doped semiconductor portion is less than or equal to 60%.

[0027] In the case of adopting the above technical solution, it can be understood that the degree of crystallization of the second doped semiconductor part will affect its own conductivity, thereby affecting the leakage loss of the back contact battery in the reverse leakage region and the reverse breakdown voltage of the back contact battery when it is blocked. Based on this, when the degree of crystallization of the second doped semiconductor part is within the above range, the degree of crystallization of the second doped semiconductor part has a larger optional range. At this time, when the back contact battery provided by the present invention is set in an installation environment with fewer obstructions such as bird droppings, leaves or sand, the degree of crystallization of the second doped semiconductor part can be set within a smaller range to reduce the recombination rate of carriers of opposite conductivity types between the first doped semiconductor part and the second doped semiconductor part in the reverse leakage region, thereby helping to reduce the leakage loss of the back contact battery in the forward voltage region and ensure that the back contact battery has a higher working efficiency. When the back contact battery provided by the invention is set in an installation environment with more obstructions such as bird droppings, leaves or sand, the degree of crystallization of the second doped semiconductor part can be set within a larger range to improve the conductivity of the second doped semiconductor part, thereby helping to reduce the reverse breakdown voltage of the back contact battery and ensure that the back contact battery has a lower risk of hot spots. It can be seen from this that the degree of crystallization of the second doped semiconductor portion can be set according to different environmental requirements, thereby improving the applicability of the back contact battery provided by the present invention in different practical application scenarios.

[0028] As a possible implementation, the thickness of the second doped semiconductor portion is greater than or equal to 5 nm and less than or equal to 50 nm. The application principle of the beneficial effect in this case is similar to the application principle of the beneficial effect of the first doped semiconductor portion having a thickness greater than or equal to 50 nm and less than or equal to 200 nm described above, and will not be repeated here.

[0029] As a possible implementation solution, the electrical conductivity of the second doped semiconductor portion is greater than or equal to 10E-5 S / cm and less than or equal to 1 S / cm.

[0030] In the case of adopting the above technical solution, it can be understood that the conductivity of the second doped semiconductor part directly affects its own conductivity. And the conductivity of the second doped semiconductor part will affect the leakage loss of the back contact battery in the reverse leakage region and the reverse breakdown voltage of the back contact battery when it is shaded. Based on this, when the conductivity of the second doped semiconductor part is within the above range, it is possible to prevent the forward leakage loss of the back contact battery from being large due to the too high conductivity of the second doped semiconductor part caused by the large conductivity of the second doped semiconductor part; in addition, it is also possible to prevent the reverse breakdown voltage of the back contact battery from being high due to the too low conductivity of the second doped semiconductor part caused by the small conductivity of the second doped semiconductor part, which is further conducive to balancing the reverse breakdown voltage and the working efficiency corresponding to the back contact battery.

[0031] As a possible implementation solution, the above semiconductor substrate is a silicon substrate.

[0032] As a possible implementation solution, when the first doped semiconductor part is formed on the first region and the overlapping region, the back contact battery further includes a first interface passivation layer located between the first doped semiconductor part and the semiconductor substrate.

[0033] 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 part has excellent interface passivation effect, and can realize the selective collection of carriers, reduce the carrier recombination rate in the first region and the overlapping region of the first surface of the semiconductor substrate, and further improve the photoelectric conversion efficiency of the back contact battery.

[0034] As a possible implementation solution, the above back contact battery further includes a second interface passivation layer, and the second interface passivation layer is located between the second region on the first surface and the second doped semiconductor part and extends between the second doped semiconductor part and the first doped semiconductor part.

[0035] 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 part 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.

[0036] As a possible implementation solution, the thickness of the above second interface passivation layer is greater than or equal to 2nm and less than or equal to 20nm.

[0037] When the above technical solution is adopted, the thickness of the second interface passivation layer will affect its own transmission resistance and passivation effect. Based on this, the thickness of the second interface passivation layer is within the above range, which is conducive to preventing the second interface passivation layer from having a poor passivation effect on the second region due to its small thickness, and ensuring that the surface of the second region has a low carrier recombination rate. It can also prevent the second interface passivation layer from having a large thickness, which makes its own transmission resistance large, resulting in a low carrier collection efficiency of the second doped semiconductor part under normal operation of the back contact battery, and a small reduction in the reverse breakdown voltage when the back contact battery is blocked, which is further conducive to achieving a balance between the reverse breakdown voltage and working efficiency of the back contact battery.

[0038] As a possible implementation solution, when the doping concentration of the dopant in the first doped semiconductor portion is greater than or equal to 1E19 cm -3 , and less than or equal to 5E19cm -3 When the thickness of the second interface passivation layer is greater than or equal to 5 nm and less than or equal to 15 nm. Alternatively, when the doping concentration of the dopant in the first doped semiconductor portion is greater than 5E19 cm -3 , and less than or equal to 1E20cm -3 When the thickness of the second interface passivation layer is greater than or equal to 6 nm and less than or equal to 17 nm. Alternatively, when the doping concentration of the dopant in the first doped semiconductor portion is greater than 1E20 cm -3 , and less than or equal to 5E20cm -3 When the thickness of the second interface passivation layer is greater than or equal to 7 nm and less than or equal to 20 nm.

[0039] When the above technical solution is adopted, the doping concentration of the dopant in the first doped semiconductor part will affect its own conductivity. Specifically, within a certain range, the higher the doping concentration of the dopant in the first doped semiconductor part, the higher the conductivity of the first doped semiconductor part; on the contrary, the lower the doping concentration of the dopant in the first doped semiconductor, the lower the conductivity of the first doped semiconductor part. As for the above-mentioned second interface passivation layer, the thickness of the second interface passivation layer is related to its own passivation effect and transmission resistance. When the thickness of the second interface passivation layer is small, in the reverse leakage region, the leakage current between the first doped semiconductor part and the second doped semiconductor part is larger. Based on this, the back contact battery provided by the present invention is provided with a second interface passivation layer of corresponding thickness according to the different doping concentrations of the dopant in the first doped semiconductor part, so as to realize reasonable regulation of the working efficiency and reverse breakdown voltage of the back contact battery, and ensure that the back contact battery has high working performance and working reliability.

[0040] As a possible implementation, in a back-contact cell comprising a first interface passivation layer and a second interface passivation layer, the first interface passivation layer and the first doped semiconductor portion constitute a first passivation contact structure, and the second interface passivation layer and the second doped semiconductor portion constitute a second passivation contact structure. The first passivation contact structure and the second passivation contact structure may have different passivation contact types; and / or the first passivation contact structure has greater thermal stability than the second passivation contact structure; and / or the first passivation contact structure is a tunneling passivation contact structure; and / or the second passivation contact structure is a heterogeneous contact structure.

[0041] When the above technical solution is adopted, when the passivation contact types of the first passivation contact structure and the second passivation contact structure are different, the passivation contact types of the first passivation contact structure and the second passivation contact structure can be adjusted according to the requirements of different actual application scenarios, so as to improve the applicability of the back contact battery provided by the present invention in different application scenarios. For example: in the actual manufacturing process, after forming the first passivation contact structure in the first area and the overlapping area, and forming the second passivation contact structure set as a whole layer, it is usually necessary to use a laser processing process to pattern the mask material set as a whole layer to form a mask layer for selectively etching the second passivation contact structure. In order to process all parts of the mask material corresponding to the first area, the heat of the processing laser radiation will be transferred to the first passivation contact structure. Because the heat of the laser is relatively high, when the first passivation contact structure has a high thermal stability, the influence of the heat of the laser radiation on the first passivation contact structure can be reduced, and even the heat of the laser radiation will not affect the first passivation contact structure, thereby improving the yield of the back contact battery. The portion of the second passivation contact structure corresponding to the first area needs to be removed, and the laser processing process has a high precision. Therefore, the portion of the second passivation contact structure corresponding to the overlapping area and the second area will not be affected by heat, or the thermal impact is small. At this time, the manufacturing process has low requirements on the thermal stability of the second passivation contact structure, and the thermal stability of the second passivation contact structure can be set to be lower than the thermal stability of the first passivation contact structure.

[0042] In addition, when the first passivation contact structure is a tunneling passivation contact structure, because amorphous silicon materials easily form polycrystalline silicon or single crystal silicon at high temperatures, and the chemical properties of tunneling passivation materials and polycrystalline silicon are relatively stable at high temperatures, compared with heterogeneous contact structures, tunneling passivation contact structures are less sensitive to high-temperature laser thermal damage. This can reduce the impact on the passivation effect during laser processing, further increasing the process window and reducing process difficulty. In addition, heterogeneous contact structures have a passivation effect superior to tunneling passivation contact structures. Therefore, when the second passivation contact structure is a heterogeneous contact structure, the carrier recombination rate at the interface between the semiconductor substrate and the second interface passivation layer can be further reduced, which is beneficial to improving the photoelectric conversion efficiency of the back contact cell.

[0043] As a possible implementation, the back-contact cell further includes a surface passivation layer disposed on the second side of the semiconductor substrate. The surface passivation layer includes an intrinsic semiconductor passivation layer and a silicon nitride passivation layer stacked sequentially along the thickness of the semiconductor substrate on the second side. The intrinsic semiconductor passivation layer is made of at least one of amorphous silicon, microcrystalline silicon, and nanocrystalline silicon.

[0044] When using the above technical solution, the intrinsic semiconductor passivation layer included in the surface passivation layer can be formed simultaneously with the fabrication of the interface passivation layer included in the heterogeneous contact structure on the first side. The silicon nitride passivation layer included in the surface passivation layer can be formed simultaneously with the fabrication of the mask material for implementing the second passivation contact structure on the first side. This eliminates the need for additional steps to form the surface passivation layer, thereby improving the manufacturing efficiency of back-contact cells.

[0045] As a possible implementation scheme, the cross-sectional area of the above-mentioned insulating groove gradually decreases in the direction approaching the semiconductor substrate; and / or, in the transparent conductive layer, the thickness of each region along the first direction of the part whose orthographic projection on the first surface does not overlap with the orthographic projection of the insulating groove on the first surface is the same.

[0046] When the above technical solution is adopted, when the cross-sectional area of the insulating groove gradually decreases in the direction close to the semiconductor substrate, the cross-sectional area at the bottom of the insulating groove is smaller than the cross-sectional area at the groove mouth of the insulating groove. At this time, the thickness of the end of the transparent conductive layer close to the insulating groove gradually increases in the direction away from the insulating groove. Based on this, especially for the reverse leakage area, the leakage current flows from the edge of the transparent conductive layer to the corresponding electrode. At this time, the density of the leakage current at the edge of the transparent conductive layer is relatively small, and almost all the leakage current in the part of the transparent conductive layer away from its own edge area will pass through here. Therefore, the leakage current density of the part of the transparent conductive layer away from its own edge area is relatively large. In the above case, when the thickness of the transparent conductive layer close to the end of the insulating groove gradually increases in the direction away from the insulating groove, the thickness of the part of the transparent conductive layer away from its own edge area is relatively large, which is more conducive to the transmission of leakage current and helps to further reduce the risk of hot spots in back-contact batteries. In the transparent conductive layer, when the thickness of each region along the first direction of the portion where the orthographic projection on the first surface does not overlap with the orthographic projection of the insulating groove on the first surface is the same, it is beneficial for the portion of the transparent conductive layer away from its own edge region to have a larger thickness along the first direction. This is not only beneficial for the transmission of leakage current when the back contact battery is blocked, but also beneficial for the back contact battery to extract the photocurrent generated in the forward voltage region, further improving the working performance of the back contact battery and reducing the risk of hot spots.

[0047] As a possible implementation solution, the crystallization degree of at least part of the second doped semiconductor part located in the second region is greater than that of the part of the second doped semiconductor part corresponding to the first transparent conductive part.

[0048] In the case of adopting the above technical solution, it can be understood that when the back contact battery is in a normal working state, the part of the second doped semiconductor part located in the second region needs to collect and export the carriers of the corresponding conductivity type generated in the semiconductor substrate, so as to facilitate the formation of photocurrent. And the part of the second doped semiconductor part corresponding to the first transparent conductive layer is electrically connected to the first doped semiconductor part with the opposite conductivity type. When the back contact battery is in a normal working state, there will be a leakage current between the part of the second doped semiconductor part corresponding to the first transparent conductive layer and the first doped semiconductor part. Secondly, under the condition that other factors are the same, when the crystallization degree of the doped semiconductor part is smaller, the grains in the doped semiconductor part are smaller, and even show the disorder of amorphous semiconductor materials. And the smaller the grains and / or the fewer the number of grains in the doped semiconductor part, the more interfaces there are between the grains in the doped semiconductor part, so the resistance at the grain interfaces will be larger. In the above case, when the crystallization degree of at least part of the second doped semiconductor part located in the second region is set to be greater than that of the part of the second doped semiconductor part corresponding to the first transparent conductive part, the conductivity of at least part of the second doped semiconductor part located in the second region will be greater, which is beneficial to reducing the transmission loss of at least part of the second doped semiconductor part located in the second region and reducing the contact resistance between at least part of the second doped semiconductor part located in the second region and the transparent conductive layer. And the crystallization degree of the part of the second doped semiconductor part corresponding to the first transparent conductive part is smaller. At this time, the conductivity of the part of the second doped semiconductor part corresponding to the first transparent conductive part is relatively low, which is beneficial to reducing the magnitude of the forward leakage current between the part of the second doped semiconductor part corresponding to the first transparent conductive layer and the first doped semiconductor part, and further improving the conversion efficiency of the back contact battery.

[0049] As a possible implementation solution, the crystallization degree of at least part of the second doped semiconductor part located in the second region is greater than that of the part of the second doped semiconductor part located in the overlapping region. It can be understood that in the overlapping region, the first doped semiconductor part and the second doped semiconductor part are electrically connected. When the battery is working normally, reducing the crystallization degree of this part can effectively better reduce the forward leakage current.

[0050] As a possible implementation solution, the crystallization degree of at least part of the second doped semiconductor part located in the second region is greater than that of the part of the second doped semiconductor part covering the side wall; the side wall is located at the junction of the overlapping region and the second region.

[0051] In the case of adopting the above technical solution, it can be understood that in the second doped semiconductor portion, the portion on the sidewall at the junction of the overlapping region and the second region is closer to the second region than the portion corresponding to the second region. Based on this, when the crystallization degree of the portion of the second doped semiconductor portion covering the sidewall at the junction of the overlapping region and the second region is relatively small, it is beneficial to prevent the crystallization modification of at least a part of the second doped semiconductor portion corresponding to the second region by laser treatment or the like during the actual manufacturing process from also affecting at least the portion of the second doped semiconductor portion corresponding to the first transparent conductive portion, ensuring that at least the portion of the second doped semiconductor portion corresponding to the first transparent conductive portion has a relatively small conductivity and effectively controlling the magnitude of the forward leakage current between the portion of the second doped semiconductor portion corresponding to the first transparent conductive portion and the first doped semiconductor portion.

[0052] As a possible implementation solution, the above-mentioned second doped semiconductor portion includes a highly crystallized region and a lowly crystallized region; the crystallization degree of the portion of the second doped semiconductor portion located in the lowly crystallized region is less than the crystallization degree of the portion of the second doped semiconductor portion located in the highly crystallized region; in the second doped semiconductor portion, at least the portion corresponding to the first transparent conductive portion is located in the lowly crystallized region, and at least a part corresponding to the second region is located in the highly crystallized region. The application principle of the beneficial effects in this case is similar to the application principle of the beneficial effects described above, where the crystallization degree of at least a part of the second doped semiconductor portion located in the second region is greater than the crystallization degree of the portion of the second doped semiconductor portion corresponding to the first transparent conductive portion, and will not be elaborated here.

[0053] As a possible implementation solution, the above-mentioned lowly crystallized region is located within the overlapping region; or, along the first direction, one side edge of the above-mentioned lowly crystallized region is located within the overlapping region and the other side edge extends to the sidewall, and this sidewall is located at the junction of the overlapping region and the second region; or, along the first direction, one side edge of the above-mentioned lowly crystallized region is located within the overlapping region and the other side edge extends to the second region; or, the above-mentioned highly crystallized region corresponds to the entire second region.

[0054] In the case of adopting the above technical solution, since at least part of the overlapping region is a reverse leakage region, when the above low-crystallinity region is located in the overlapping region, it can be ensured that the conductivity of the part of the second doped semiconductor region located in the reverse leakage region is relatively small, effectively controlling the magnitude of the forward leakage current between the second doped semiconductor region and the first doped semiconductor region in the reverse leakage region, which is beneficial to improving the conversion efficiency of the back contact battery. In addition, when, along the first direction, one side edge of the above low-crystallinity region is located in the overlapping region and the other side edge extends to the side wall at the junction of the overlapping region and the second region, or when, along the first direction, one side edge of the above low-crystallinity region is located in the overlapping region and the other side edge extends to the second region, it is beneficial to prevent the above operation from affecting the second doped semiconductor region located in the overlapping region while making at least part of the second doped semiconductor region corresponding to the second region located in the high-crystallinity region by means of laser treatment or the like, ensuring that the part of the second doped semiconductor region located in the overlapping region has a small conductivity while reducing the requirements for the precision of the processing technology. In addition, when the high-crystallinity region corresponds to the entire second region, the part of the second doped semiconductor region corresponding to the entire second region has a relatively high conductivity, so that the part of the second doped semiconductor region corresponding to the entire second region has a high carrier collection efficiency, improving the working efficiency of the back contact battery.

[0055] 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.

[0056] For the beneficial effects of the second aspect and its various implementation manners in the present invention, reference can be made to the analysis of the beneficial effects in the first aspect and its various implementation manners, and details are not described herein again.

[0057] In a third aspect, the present invention provides a method for manufacturing a back contact battery. The method for manufacturing the back contact battery includes: First, providing a semiconductor substrate. The semiconductor substrate includes opposite first and second surfaces. The first surface includes a first region, a second region, and an overlapping region located between the first region and the second region. The first region, the overlapping region, and the second region are arranged in a first direction. Next, forming a first doped semiconductor portion disposed in the first region and the overlapping region. Next, forming a second doped semiconductor portion disposed on the second region and extending to cover a portion of the side of the first doped semiconductor portion facing away from the semiconductor substrate corresponding to the overlapping region. The second doped semiconductor portion and the first doped semiconductor portion have opposite conductivity types. Then, forming a transparent conductive layer covering the second doped semiconductor portion and the first doped semiconductor portion. An insulating groove is provided in the transparent conductive layer to separate a portion of the transparent conductive layer corresponding to the first region from a portion of the transparent conductive layer corresponding to the second region. Wherein, at least a portion of the overlapping region is a reverse leakage region. In the reverse leakage region, a portion of the transparent conductive layer extending from the second region into the overlapping region is a first transparent conductive portion, and the first transparent conductive portion is electrically connected to the first doped semiconductor portion through the second doped semiconductor portion. The width of the first transparent conductive portion in the first direction is W1, the width of the overlapping region in the first direction is W2, and the ratio of W1 to W2 is greater than or equal to 10% and less than or equal to 90%.

[0058] As a possible implementation, forming the first doped semiconductor portion disposed in the first region and the overlapping region includes: forming a first doped semiconductor portion disposed entirely on or within the first surface. Next, forming an insulating mask layer on portions of the first doped semiconductor portion corresponding to the first region and the overlapping region. Next, under the protection of the insulating mask layer, removing the portion of the first doped semiconductor portion corresponding to the second region. Then, removing the insulating mask layer.

[0059] As a possible implementation, after forming the transparent conductive layer, or while forming the insulating groove in the transparent conductive layer, the method for manufacturing the back contact battery further includes: selectively etching at least the first transparent conductive portion to make the first transparent conductive portion discontinuously distributed in a second direction. The second direction intersects the first direction.

[0060] As a possible implementation solution, the above-mentioned first doped semiconductor part formed in the first region and the overlapping region includes: a first doped semiconductor part formed as a whole layer on or in the first surface; and a laser etching process is used to selectively remove the part of the first doped semiconductor part corresponding to the second region. And / or, the above-mentioned second doped semiconductor part formed on the second region and extending to cover the part corresponding to the overlapping region on the side of the first doped semiconductor part facing away from the semiconductor substrate includes: a second doped semiconductor part formed as a whole layer on the first doped semiconductor part and the second region; and a laser etching process is used to selectively remove the part of the second doped semiconductor part corresponding to the first region. And / or, the above-mentioned transparent conductive layer formed to cover the second doped semiconductor part and the first doped semiconductor part includes: a transparent conductive layer formed as a whole layer on the first doped semiconductor part and the second doped semiconductor part; and a laser etching process is used to open an insulating groove in the transparent conductive layer. In the above cases, when manufacturing at least one of the first doped semiconductor part, the second doped semiconductor part, and the transparent conductive layer, the laser etching process is used to directly perform selective etching on the corresponding film layer formed as a whole layer, which can save the deposition process and removal process of the mask layer, reduce the manufacturing cost of the back-contact battery, and at the same time improve the manufacturing efficiency of the back-contact battery. And only need to slightly adjust the pattern of selective etching applied in the laser etching process, without changing other manufacturing processes of the back-contact battery, improve the compatibility between the manufacturing method provided by the present invention and the existing manufacturing processes, and reduce the manufacturing difficulty.

[0061] For the beneficial effects of the third aspect and its various implementation manners in 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] The drawings described herein are used to provide a further understanding of the present invention and constitute 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 to the present invention. In the drawings:

[0063] Figure 1 It is a longitudinal sectional schematic view of the first structure of the back-contact battery provided by an embodiment of the present invention;

[0064] Figure 2 It is a longitudinal sectional schematic view of the second structure of the back-contact battery provided by an embodiment of the present invention;

[0065] Figure 3 It is a longitudinal sectional schematic view of the third structure of the back-contact battery provided by an embodiment of the present invention;

[0066] Figure 4 It is a longitudinal sectional schematic view of the fourth structure of the back-contact battery provided by an embodiment of the present invention;

[0067] Figure 5 Top view schematic diagram of the first structure of the back contact battery provided by the embodiment of the present invention on one side of the first surface;

[0068] Figure 6 Top view schematic diagram of the second structure of the back contact battery provided by the embodiment of the present invention on one side of the first surface;

[0069] Figure 7 Top view schematic diagram of the third structure of the back contact battery provided by the embodiment of the present invention on one side of the first surface;

[0070] Figure 8 Schematic diagram of the structure of the back contact battery provided by the embodiment of the present invention during the manufacturing process Figure 1 ;

[0071] Figure 9 Schematic diagram of the structure of the back contact battery provided by the embodiment of the present invention during the manufacturing process Figure 2 ;

[0072] Figure 10 Schematic diagram of the structure of the back contact battery provided by the embodiment of the present invention during the manufacturing process Figure 3 ;

[0073] Figure 11 Schematic diagram of the structure of the back contact battery provided by the embodiment of the present invention during the manufacturing process Figure 4 ;

[0074] Figure 12 Schematic diagram of the structure of the back contact battery provided by the embodiment of the present invention during the manufacturing process Figure 5 ;

[0075] Figure 13 Schematic diagram of the structure of the back contact battery provided by the embodiment of the present invention during the manufacturing process Figure 6 ;

[0076] Figure 14 Schematic diagram of the structure of the back contact battery provided by the embodiment of the present invention during the manufacturing process Figure 7 ;

[0077] Figure 15 Schematic diagram of the structure of the back contact battery provided by the embodiment of the present invention during the manufacturing process Figure 8 ;

[0078] Figure 16 Schematic diagram of the structure of the back contact battery provided by the embodiment of the present invention during the manufacturing process Figure 9 ;

[0079] Figure 17 Schematic diagram of the structure of the back contact battery provided by the embodiment of the present invention during the manufacturing processFigure 10 ;

[0080] Figure 18 Structural schematic of the back-contact battery provided by the embodiment of the present invention during manufacturing Figure 10 One;

[0081] Figure 19 Structural schematic of the back-contact battery provided by the embodiment of the present invention during manufacturing Figure 10 Two;

[0082] Figure 20 Structural schematic of the back-contact battery provided by the embodiment of the present invention during manufacturing Figure 10 Three.

[0083] Reference numerals: 11 is a semiconductor substrate, 12 is a first doped semiconductor part, 13 is a second doped semiconductor part, 14 is a transparent conductive layer, 15 is a first region, 16 is a second region, 17 is an overlapping region, 18 is an insulating groove, 19 is a first transparent conductive part, 20 is a second transparent conductive part, 21 is a continuous region, 22 is a discontinuous region, 23 is a third transparent conductive part, 24 is a notch, 25 is a first electrode, 26 is a first interface passivation layer, 27 is a second interface passivation layer, 28 is a surface passivation layer, 29 is a second electrode, 30 is an insulating mask layer. Detailed implementation manners

[0084] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present disclosure.

[0085] Various structural schematic diagrams according to embodiments of the present disclosure are shown in the drawings. These figures are not drawn to scale, and for the purpose of clear expression, some details are enlarged and some 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. In practice, there may be deviations due to manufacturing tolerances or technical limitations, and those skilled in the art can design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0086] In the context of the present disclosure, 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 an intermediate layer / component 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 more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not used to limit the present invention.

[0087] 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, the 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" means two or more, unless otherwise specifically defined. "Several" means one or more, unless otherwise specifically defined.

[0088] In a first aspect, an embodiment of the present invention provides a back-contact battery. As Figure 1As shown in the figure, the back contact battery provided by the embodiment of the present invention includes: a semiconductor substrate 11, a first doped semiconductor portion 12, a second doped semiconductor portion 13, and a transparent conductive layer 14. The conductive types of the second doped semiconductor portion 13 and the first doped semiconductor portion 12 are opposite. The semiconductor substrate 11 includes opposite first and second surfaces. The first surface includes a first region 15, a second region 16, and an overlapping region 17 located between the first region 15 and the second region 16. Moreover, the first region 15, the overlapping region 17, and the second region 16 are arranged along a first direction. The first doped semiconductor portion 12 is disposed on the first region 15 and the overlapping region 17. The second doped semiconductor portion 13 is disposed on the second region 16 and extends to cover the first doped semiconductor portion 12 in the overlapping region 17. The transparent conductive layer 14 covers the second doped semiconductor portion 13 and the first doped semiconductor portion 12. An insulating groove 18 is provided in the transparent conductive layer 14 to physically insulate the portion of the transparent conductive layer 14 corresponding to the first region 15 from the portion of the transparent conductive layer 14 corresponding to the second region 16. Among them, at least part of the overlapping region 17 is a reverse leakage region. And in the reverse leakage region, the portion of the transparent conductive layer 14 extending from the second region 16 into the overlapping region 17 is a first transparent conductive portion 19, and the first transparent conductive portion 19 is electrically connected to the first doped semiconductor portion 12 through the second doped semiconductor portion 13. The width of the first transparent conductive portion 19 in the first direction is W1, the width of the overlapping region 17 in the first direction is W2, and the ratio of W1 to W2 is greater than or equal to 10% and less than or equal to 90%.

[0089] In the case of adopting the above technical solution, when the back contact battery is in a working state, the first doped semiconductor portion and the second doped semiconductor portion can effectively shunt carriers, which is beneficial to the formation of photocurrent. And the transparent conductive layer covering the second doped semiconductor portion and the first doped semiconductor portion has a high conductivity, which can timely export the carriers collected by the first doped semiconductor portion and the second doped semiconductor portion, reducing the carrier recombination rate. As Figure 1As shown, the second doped semiconductor portion 13 is not only provided on the second region 16, but also extends to cover the first doped semiconductor portion 12 in the overlapping region 17. Moreover, at least a portion of the overlapping region 17 is a reverse leakage region. In this reverse leakage region, the portion of the transparent conductive layer 14 extending from the second region 16 into the overlapping region 17 (i.e., the first transparent conductive portion 19) can be electrically connected to the first doped semiconductor portion 12 of the opposite conductivity type through the second doped semiconductor portion 13. At this time, the portion where the first doped semiconductor portion 12 and the second doped semiconductor portion 13 overlap each other forms a built-in diode structure with a low reverse breakdown voltage. When the back contact cell is blocked, the leakage current (it should be emphasized that for the sake of convenience and clarity of description, when the embodiment of the present invention is When the transmission mode of the leakage current is mentioned, it not only includes its own transmission path, but also its own transmission direction. However, it does not mean that the transmission direction of the leakage current can only be a single direction in the description. When the conductivity type of the first doped semiconductor part and the second doped semiconductor part changes, the transmission direction of the leakage current can also be opposite to the direction in the description, that is, in the embodiment of the present invention, only the transmission path of the leakage current is limited, and the transmission direction of the leakage current is not limited. The leakage current is led out through the overlapping part of the first doped semiconductor part 12 and the second doped semiconductor part 13, and then through the first transparent conductive part 19 and the electrode in contact with it. It should be noted that in the reverse leakage region, the first transparent conductive part is electrically connected to the first doped semiconductor part of the opposite conductivity type through the second doped semiconductor part. This electrical connection mode does not include electrical connection achieved through the semiconductor substrate. Secondly, in the back contact battery provided by the present invention, the insulating groove provided in the transparent conductive layer can physically insulate the part of the transparent conductive layer corresponding to the first region from the part of the transparent conductive layer corresponding to the second region. This physical insulation means no contact to prevent the back contact battery from having a short circuit problem.

[0090] In addition, in the back-contact cell provided by the embodiment of the present invention, there is no need to set an insulating layer for separating the first doped semiconductor portion and the second doped semiconductor portion 13 at the portion where they overlap with each other, which is beneficial to simplifying the manufacturing process of the back-contact cell while taking advantage of the electrical connection between the two in the reverse leakage region to reduce the risk of hot spots. Moreover, along the first direction, the larger the width of the first transparent conductive portion provided in the reverse leakage region, the smaller the transmission resistance of the leakage current in the first transparent conductive portion, the greater the corresponding reduction in the reverse breakdown voltage, and the leakage loss of the back-contact cell in the forward voltage region may be higher. Conversely, along the first direction, the smaller the width of the first transparent conductive portion provided in the reverse leakage region, the larger the transmission resistance of the leakage current in the first transparent conductive portion, the smaller the corresponding reduction in the reverse breakdown voltage, and the leakage loss of the back-contact cell in the forward voltage region may be lower. Based on this, during the application of the back-contact battery provided by the present invention, it is only necessary to adjust the width W1 of the first transparent conductive portion 19 in the first direction and the width W2 of the overlapping region 17 in the first direction to adjust the leakage loss and reverse breakdown voltage, thereby reducing the risk of hot spots in the back-contact battery while ensuring that the back-contact battery has higher operating efficiency in the forward voltage region. Furthermore, during the actual manufacturing process, it is only necessary to fine-tune the pattern of the selective etching used to form the transparent conductive layer 14, without changing other manufacturing processes of the back-contact battery. This improves the compatibility of the back-contact battery provided by the embodiment of the present invention with existing manufacturing processes and reduces the manufacturing difficulty of the back-contact battery provided by the embodiment of the present invention.

[0091] In actual applications, the embodiments of the present invention do not specifically limit the material and conductivity type of the semiconductor substrate. For example, the semiconductor substrate may be a silicon substrate. Alternatively, the semiconductor substrate may be a substrate made of any other semiconductor material, such as a silicon germanium substrate, a germanium substrate, or a gallium arsenide substrate.

[0092] Secondly, the above-mentioned semiconductor substrate includes a first surface and a second surface relative to each other, the first surface of the semiconductor substrate corresponds to the backlight surface of the back contact battery, and the second surface of the semiconductor substrate corresponds to the light-facing surface of the back contact battery. Among them, the distribution of the first area, the second area and the overlapping area on the first surface of the first surface can be determined according to the distribution of the first doped semiconductor part and the second doped semiconductor part formed on one side of the first surface. Specifically, since the first doped semiconductor part included in the back contact battery is arranged in the first area and the overlapping area, the distribution range of the first area and the overlapping area on the first surface can be determined according to the distribution requirements of the first doped semiconductor part in the actual application scenario. Since part of the area of the second doped semiconductor part included in the back contact battery is arranged on the second area of the first surface, the distribution range of the second area on the first surface can be determined according to the distribution requirements of the second doped semiconductor part on the semiconductor substrate in the actual application scenario.

[0093] It can be understood that the first region corresponds to the first emitter region, and the second region 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, and the overlapping region is a PN overlapping region.

[0094] For example, the first region and the second region may be arranged alternately at intervals in a strip shape, or may be arranged alternately at intervals in an interdigitated shape.

[0095] The arrangement direction of the first region, the overlapping region, and the second region (i.e., the first direction) can be determined based on the distribution of the first region, the second region, and the overlapping region on the first surface, and is not specifically limited here. For example, when the first region and the second region are arranged in an alternating strip pattern, the first direction is parallel to the arrangement direction of the two adjacent strip regions. For another example, when the first region and the second region are arranged in an alternating interdigitated pattern, the first direction is parallel to the arrangement direction of the two adjacent "F"-shaped regions.

[0096] In terms of surface morphology, Figure 1 and Figure 2 As shown, the first and second surfaces of the semiconductor substrate 11 may be planes. Alternatively, Figure 3 As shown, the second surface of the semiconductor substrate 11 can also be a velvet surface to enhance the light trapping effect of the second surface and improve the light utilization efficiency of the semiconductor substrate 11. Secondly, the surface of the second region of the first surface can also be a velvet surface to increase the contact area between the second doped semiconductor portion 13 on the second region and the transparent conductive layer 14 on the second region, as well as to increase the contact area between the transparent conductive layer 14 on the second region and the corresponding electrode, thereby reducing transmission loss.

[0097] Regarding the first doped semiconductor portion, the present invention does not impose any specific restrictions on the conductivity type of the first doped semiconductor portion, as long as the first doped semiconductor portion and the second doped semiconductor portion have opposite conductivity types. Specifically, the conductivity type of the first doped semiconductor portion can be N-type, in which case the conductivity type of the second doped semiconductor portion is P-type; alternatively, the conductivity type of the first doped semiconductor portion can be P-type, in which case the conductivity type of the second doped semiconductor portion is N-type.

[0098] In terms of the formation position, Figure 1 As shown, the first doped semiconductor portion 12 may be provided on the first region 15 and the overlapping region 17 of the semiconductor substrate; or Figure 2 As shown, the first doped semiconductor portion 12 may also be disposed in the first region 15 and the overlapping region 17 of the semiconductor substrate. In this case, the first doped semiconductor portion 12 may be formed by diffusion or ion implantation.

[0099] Among them, when the first doped semiconductor part is disposed on the first region and the overlapping region of the semiconductor substrate, the material of the first doped semiconductor part 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 part may be amorphous, microcrystalline, nanocrystalline, single crystal, or polycrystalline, etc.

[0100] Secondly, as Figure 1 shown, the first doped semiconductor part 12 may be directly disposed on the first region 15 and the overlapping region 17. Or, as Figure 3 shown, the above back contact battery may further include a first interface passivation layer 26 located between the first doped semiconductor part 12 and the semiconductor substrate 11. In this case, the passivation contact structure composed of the first interface passivation layer 26 and the first doped semiconductor part 12 has an excellent interface passivation effect, and can achieve selective collection of carriers, reduce the carrier recombination rate in the first region 15 and the overlapping region 17 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 26 may be set according to the material of the first doped semiconductor part 12 and actual requirements, and are not specifically limited here. For example: when the material of the first doped semiconductor part is doped polysilicon, the first interface passivation layer is a tunneling passivation layer. Another example: when the material of the first doped semiconductor part includes at least one of doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon, the first 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.

[0101] Exemplarily, the thickness of the first doped semiconductor portion can be greater than or equal to 50 nm and less than or equal to 200 nm. For example, the thickness of the first doped semiconductor portion can be 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 150 nm, 180 nm, 200 nm, etc. In this case, when the thickness of the first doped semiconductor portion is within the above range, it can prevent the field passivation effect of the first doped semiconductor portion from being low due to the small layer thickness of the first doped semiconductor portion; it can also prevent the large consumption of materials for manufacturing the first doped semiconductor portion due to the large thickness of the first doped semiconductor portion, which is beneficial to controlling the manufacturing cost of the back contact battery. In addition, the thickness of the first doped semiconductor portion will affect the docking height between the side surface of the first doped semiconductor portion and the side surface of the second doped semiconductor portion, and further affect the junction area of the PN junction formed between the first doped semiconductor portion and the second doped semiconductor portion in the reverse leakage region. Based on this, when the thickness of the first doped semiconductor portion is within the above range, it can also prevent the large leakage current at the side docking portion between the first doped semiconductor portion and the second doped semiconductor portion due to the large docking height caused by the large thickness of the first doped semiconductor portion, ensuring that the leakage loss and reverse breakdown voltage of the back contact battery can be effectively regulated by adjusting the width W1 of the first transparent conductive portion in the first direction and the width W2 of the overlapping region in the first direction, so that the back contact battery has high working performance and working reliability.

[0102] Exemplarily, the doping concentration of the dopant in the above-mentioned first doped semiconductor portion can be greater than or equal to 1E19 cm -3 and less than or equal to 5E20 cm -3 . For example, the doping concentration of the dopant in the first doped semiconductor portion can be 1E19 cm -3 , 2E19 cm -3 , 4E19 cm -3 , 6E19 cm -3 , 8E19 cm -3 , 1E20 cm -3 , 3E20 cm -3 or 5E20 cm -3etc. In this case, when the doping concentration of the dopant in the first doped semiconductor portion is within the above range, it is possible to prevent the field passivation effect of the first doped semiconductor portion on the semiconductor substrate from being low due to the low doping concentration of the dopant in the first doped semiconductor portion, ensuring that the first region and the overlapping region of the back contact battery have a relatively low carrier recombination rate under normal operating conditions; at the same time, it is also beneficial to make the first doped semiconductor portion have good conductivity, ensuring that the portion of the first doped semiconductor portion in the reverse leakage region has a relatively low transfer resistance when the back contact battery is shaded, and further facilitating the reduction of the reverse breakdown voltage of the back contact battery. In addition, it is also possible to prevent the difficulty of doping the intrinsic semiconductor layer used to manufacture the first doped semiconductor portion from being high due to the high doping concentration of the dopant in the first doped semiconductor portion, reducing the process difficulty and facilitating the improvement of the yield of the back contact battery.

[0103] For the above-mentioned second doped semiconductor portion, in terms of materials, the material of the second doped semiconductor portion 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 portion may be amorphous, microcrystalline, nanocrystalline, single crystal, or polycrystalline, etc. As for the specific value of the crystallization rate of the second doped semiconductor portion, it can be determined according to the actual application scenario and will not be specifically limited here.

[0104] Exemplarily, the crystallization rate of the above-mentioned second doped semiconductor portion may be less than or equal to 60%. For example: the crystallization rate of the second doped semiconductor portion may be 0, 5%, 10%, 20%, 30%, 40%, 50%, or 60%, etc. In this case, it can be understood that the crystallization rate of the second doped semiconductor portion affects its own conductivity, and thus affects the leakage loss of the back contact battery in the reverse leakage region and the reverse breakdown voltage of the back contact battery when it is shaded. Based on this, when the crystallization rate of the second doped semiconductor portion is within the above range, the crystallization rate of the second doped semiconductor portion has a relatively large selection range. At this time, in addition to adjusting the leakage loss and reverse breakdown voltage of the back contact battery by adjusting the ratio range of the above-mentioned W1 and W2, it is also possible to adjust the crystallization rate of the second doped semiconductor portion to achieve a comprehensive and precise control of the leakage loss and reverse breakdown voltage of the back contact battery, ensuring that the back contact battery has high working performance and working reliability.

[0105] In terms of conductivity, the conductivity of the second doped semiconductor portion directly affects its own conductivity. And the conductivity of the second doped semiconductor portion affects the leakage loss of the back contact battery in the reverse leakage region and the reverse breakdown voltage of the back contact battery when it is shaded. Based on this, the conductivity between the first electrode 25 and the second doped semiconductor portion 13 can be determined according to the requirements for leakage loss and reverse breakdown voltage in the actual application scenario.

[0106] Exemplarily, the electrical conductivity of the second doped semiconductor portion is greater than or equal to 10E-5 S / cm and less than or equal to 1 S / cm. In this case, it is possible to prevent the back-contact cell from having a large forward leakage loss due to excessively high conductivity of the second doped semiconductor portion due to the large electrical conductivity of the second doped semiconductor portion. In addition, it is also possible to prevent the back-contact cell from having a high reverse breakdown voltage due to excessively low conductivity of the second doped semiconductor portion due to the small electrical conductivity of the second doped semiconductor portion, further facilitating a balance between the reverse breakdown voltage and operating efficiency of the back-contact cell.

[0107] In actual application, the conductive properties of different parts of the second doped semiconductor portion may be the same or different.

[0108] It is understandable that when the back contact battery is in normal working condition, the portion of the second doped semiconductor part located in the second region needs to collect and guide out the carriers of the corresponding conductive type generated in the semiconductor substrate to facilitate the formation of photocurrent. The portion of the second doped semiconductor part corresponding to the first transparent conductive layer is electrically connected to the first doped semiconductor part of the opposite conductive type (to reduce the risk of hot spots in the back contact battery). When the back contact battery is in normal working condition, the portion of the second doped semiconductor part corresponding to the first transparent conductive layer will have leakage current with the first doped semiconductor part. From the above content, it can be seen that the portions of the second doped semiconductor part located in different regions have different functions. Secondly, under the same conditions of other factors, when the degree of crystallization of the doped semiconductor part is smaller, the grains in the doped semiconductor part are smaller and / or the number of grains is smaller, and it may even present the disorder of amorphous semiconductor materials. The smaller the grains and / or the fewer the number of grains in the doped semiconductor part, the more interfaces between the grains in the doped semiconductor part, so the resistance of the grain interface will be greater. It can be seen that the degree of crystallization of the parts of the second doped semiconductor part located in different areas will affect its own conductive properties. Therefore, the conductive properties and degree of crystallization of different parts of the second doped semiconductor part can be determined according to the effects of the parts of the second doped semiconductor part located in different areas in actual application scenarios, as well as the requirements for the conversion efficiency and hot spot risk of the back contact battery.

[0109] Illustratively, the degree of crystallization of at least a portion of the second doped semiconductor portion located in the second region may be greater than the degree of crystallization of a portion of the second doped semiconductor portion corresponding to the first transparent conductive portion.

[0110] It should be noted that the greater the degree of crystallization referred to in the embodiments of the present invention may mean a greater crystallization rate, larger grain size, and / or more grain numbers. For example: when the second doped semiconductor part is a nanocrystalline silicon layer (it is generally inevitable that there may still be some amorphous silicon parts inside this nanocrystalline silicon layer, and the content of the amorphous silicon part is small, which is known in the art), the degree of crystallization of at least part of the second doped semiconductor part located in the second region is greater, and this part has a greater crystallization rate and grain size than the part of the second doped semiconductor part corresponding to the first transparent conductive part. Another example: when the second doped semiconductor part is an amorphous silicon layer (there may be a small amount of nanocrystalline silicon parts inside this amorphous silicon layer, but the content of this nanocrystalline silicon part is very small, for example, less than 5%, which is known in the art), grains with ordered lattices will be generated inside at least part of the second doped semiconductor part located in the second region, so that its degree of crystallization increases. And the degree of crystallization of the part of the second doped semiconductor part corresponding to the first transparent conductive part is smaller. At this time, the part with a smaller degree of crystallization is still an amorphous silicon material and has no grains generated after being treated by laser or the like. In this case, the conductivity of at least part of the second doped semiconductor part located in the second region will be greater, which is beneficial to reducing the transmission loss of at least part of the second doped semiconductor part located in the second region and reducing the contact resistance between at least part of the second doped semiconductor part located in the second region and the transparent conductive layer. And the degree of crystallization of the part of the second doped semiconductor part corresponding to the first transparent conductive part is smaller. At this time, the conductivity of the part of the second doped semiconductor part corresponding to the first transparent conductive part is relatively low, which is beneficial to reducing the magnitude of the forward leakage current between the part of the second doped semiconductor part corresponding to the first transparent conductive layer and the first doped semiconductor part, and further improving the conversion efficiency of the back-contact battery.

[0111] Among them, in terms of the range, it can be that only the crystallization degree of the part of the second doped semiconductor part located in the local range of the second region is relatively large, or it can be that the crystallization degree of the part of the second doped semiconductor part located in the entire second region range is large. The range of the part with a larger crystallization degree in the second doped semiconductor part can be determined according to the method of making the crystallization degrees of different regions of the second doped semiconductor part different and the actual manufacturing accuracy adopted in the actual manufacturing process, and no specific limitation is made here.

[0112] Secondly, the crystallization degree of at least a part of the second doped semiconductor portion located in the second region can be only greater than that of the portion of the second doped semiconductor portion corresponding to the first transparent conductive layer. It can also be that at least a part of the second doped semiconductor portion located in the second region is greater than the crystallization degree of the portion of the second doped semiconductor portion located in the overlapping region. It can also be that the crystallization degree of at least a part of the second doped semiconductor portion located in the second region is not only greater than that of the portion of the second doped semiconductor portion corresponding to the first transparent conductive portion, but also greater than that of the portion of the second doped semiconductor portion covering the sidewall, and the sidewall is located at the junction of the overlapping region and the second region; in this case, it can be understood that in the second doped semiconductor portion, compared with the portion corresponding to the second region, the portion on the sidewall at the junction of the overlapping region and the second region is closer to the second region. Based on this, when the crystallization degree of the portion of the second doped semiconductor portion covering the sidewall at the junction of the overlapping region and the second region is relatively small, it is beneficial to prevent the portion of the second doped semiconductor portion corresponding to at least the second region from being affected during the crystallization modification process of the second doped semiconductor portion corresponding to at least the second region by laser treatment or other means during the actual manufacturing process, ensure that the portion of the second doped semiconductor portion corresponding to at least the first transparent conductive portion has a relatively small conductivity, and effectively control the magnitude of the forward leakage current between the portion of the second doped semiconductor portion corresponding to the first transparent conductive portion and the first doped semiconductor portion.

[0113] In addition, it can be understood that the greater the crystallization degree of at least a part of the second doped semiconductor portion located in the second region, the greater the conductivity of this part. The smaller the crystallization degree of the portion of the second doped semiconductor portion corresponding to the first transparent conductive portion, the smaller the conductivity of this part. At this time, the conversion efficiency of the back contact battery is relatively high. At the same time, the degree of reduction of the hot spot risk will also be affected. Therefore, according to the requirements for the conversion efficiency and hot spot risk of the back contact battery in the actual application scenario, the difference between the crystallization degree of at least a part of the second doped semiconductor portion located in the second region and the crystallization degree of the portion of the second doped semiconductor portion corresponding to the first transparent conductive portion can be determined, and no specific limitation is made here.

[0114] Exemplarily, the difference between the crystallization rate of at least a part of the second doped semiconductor portion located in the second region and the crystallization rate of the part of the second doped semiconductor portion corresponding to the first transparent conductive portion can be greater than or equal to 40% and less than or equal to 80%. For example, the difference between the crystallization rate of at least a part of the second doped semiconductor portion located in the second region and the crystallization rate of the part of the second doped semiconductor portion corresponding to the first transparent conductive portion can be 40%, 42%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or 80%, etc. In this case, within the above range, it is beneficial to prevent the poor carrier collection efficiency of this part due to the small difference resulting in a small crystallization degree of at least a part of the second doped semiconductor portion located in the second region, and / or to prevent a large forward leakage current corresponding to this part due to a high crystallization degree of the part of the second doped semiconductor portion corresponding to the first transparent conductive portion, ensuring that the back-contact battery has a high conversion efficiency. In addition, it can also prevent a high hot spot risk of the back-contact battery due to a large difference resulting in a small crystallization degree of the part of the second doped semiconductor portion corresponding to the first transparent conductive portion, ensuring that the back-contact battery has a high anti-burning ability.

[0115] In the actual application process, the above second doped semiconductor portion may also include a high-crystallization region and a low-crystallization region; the crystallization degree of the part of the second doped semiconductor portion located in the low-crystallization region is less than the crystallization degree of the part of the second doped semiconductor portion located in the high-crystallization region. Based on this, in the second doped semiconductor portion, at least the part corresponding to the first transparent conductive portion is located in the low-crystallization region, and at least a part corresponding to the second region is located in the high-crystallization region. The application principle of the beneficial effects in this case is similar to the application principle of the beneficial effects described above where the crystallization degree of at least a part of the second doped semiconductor portion located in the second region is greater than the crystallization degree of the part of the second doped semiconductor portion corresponding to the first transparent conductive portion, and will not be elaborated here.

[0116] Among them, in terms of the range, the ranges of the high-crystallization region and the low-crystallization region in the second doped semiconductor portion can be determined according to the method of making the crystallization degrees of different regions of the second doped semiconductor portion different and the actual manufacturing precision adopted in the actual manufacturing process, and no specific limitation is made here.

[0117] Specifically, the above low-crystallization region can be located within the overlapping region. At this time, the low-crystallization region of the second doped semiconductor portion can only correspond to the part of the second doped semiconductor portion corresponding to the first transparent conductive portion; or the low-crystallization region can correspond to the entire overlapping region. And the high-crystallization region of the second doped semiconductor portion can only correspond to a part of the second doped semiconductor portion located in a local range of the second region; or, the above high-crystallization region can also correspond to the entire second region; or, the above high-crystallization region can not only correspond to at least a part of itself located in the second region, but also include the part on the side wall of the second doped semiconductor portion at the junction of the second region and the overlapping region.

[0118] Alternatively, along the first direction, one side edge of the above-mentioned low-crystallinity region is located within the overlapping region, and the other side edge extends to the side wall, and the side wall is located at the junction of the overlapping region and the second region. At this time, the high-crystallinity region of the second doped semiconductor portion can correspond to at least a partial range of the second doped semiconductor portion located in the second region.

[0119] Or, along the first direction, one side edge of the above-mentioned low-crystallinity region is located within the overlapping region, and the other side edge extends to the second region. At this time, the portion of the second doped semiconductor portion located in the high-crystallinity region only corresponds to a partial range of the second doped semiconductor portion located in the second region.

[0120] In the case of adopting the above technical solution, since at least a part of the overlapping region is a reverse leakage region, when the above-mentioned low-crystallinity region is located in the overlapping region, it can ensure that the conductivity of the portion of the second doped semiconductor portion located in the reverse leakage region is relatively small, effectively controlling the magnitude of the forward leakage current between the second doped semiconductor portion and the first doped semiconductor portion in the reverse leakage region, which is beneficial to improving the conversion efficiency of the back-contact battery. In addition, when along the first direction, one side edge of the above-mentioned low-crystallinity region is located within the overlapping region and the other side edge extends to the side wall located at the junction of the overlapping region and the second region, or when along the first direction, one side edge of the above-mentioned low-crystallinity region is located within the overlapping region and the other side edge extends to the second region, it is beneficial to prevent the above operation from affecting the second doped semiconductor portion located in the overlapping region while making at least a part of the second doped semiconductor portion corresponding to the second region located in the high-crystallinity region by means of laser treatment or the like, ensuring that the portion of the second doped semiconductor portion located in the overlapping region has a small conductivity while reducing the requirements for the precision of the processing technology. In addition, when the high-crystallinity region corresponds to the entire second region, the portion of the second doped semiconductor portion corresponding to the entire second region has a relatively high conductivity, so that the portion of the second doped semiconductor portion corresponding to the entire second region has a high carrier collection efficiency, improving the working efficiency of the back-contact battery. In addition, there are various examples of the division range of the low-crystallinity region and the high-crystallinity region in the second doped semiconductor portion, which is beneficial to reducing the process difficulty and improving the applicability of the back-contact battery provided by the embodiments of the present invention in different application scenarios.

[0121] As for the difference in the crystallization degree between the low-crystallinity region and the high-crystallinity region in the second doped semiconductor portion, it can be determined according to the requirements for the conversion efficiency and hot spot risk of the back-contact battery in the actual application scenario. Specifically, reference can be made to the difference in the crystallization degree between at least a part of the second doped semiconductor portion located in the second region and the portion of the second doped semiconductor portion corresponding to the first transparent conductive portion described above, which will not be elaborated here.

[0122] From the doping aspect, the embodiment of the present invention does not impose any specific limitation on the doping concentration of the dopant in the second doped semiconductor portion, as long as it can be applied to the back contact cell provided by the embodiment of the present invention.

[0123] For example, the doping concentration of the dopant in the second doped semiconductor portion may be greater than or equal to 1E19 cm -3 , and less than or equal to 5E20cm -3 For example, the doping concentration of the dopant in the second doped semiconductor portion may be 1E19 cm -3 、2E19cm -3 、4E19cm -3 、6E19cm -3 、8E19cm -3 、1E20cm -3 、3E20cm -3 or 5E20cm -3 In this case, the doping concentration of the dopant in the second doped semiconductor portion is within the above range, which can prevent the low field passivation effect on the semiconductor substrate caused by the low doping concentration of the dopant in the second doped semiconductor portion, ensuring that the second region of the back contact battery has a relatively low carrier recombination rate under normal operation; at the same time, it is also beneficial for the second doped semiconductor portion to have good conductivity, ensuring that the portion of the second doped semiconductor portion in the reverse leakage region has a relatively low transmission resistance when the back contact battery is blocked, further helping to reduce the reverse breakdown voltage of the back contact battery. In addition, it can also prevent the difficulty of doping the intrinsic semiconductor layer used to manufacture the second doped semiconductor portion due to the high doping concentration of the dopant in the second doped semiconductor portion, which is beneficial to improving the yield of the back contact battery.

[0124] In terms of layer thickness, the embodiment of the present invention does not specifically limit the thickness of the second doped semiconductor portion. Exemplarily, the thickness of the second doped semiconductor portion may be greater than or equal to 5 nm and less than or equal to 50 nm. For example, the thickness of the second doped semiconductor portion may be 5 nm, 10 nm, 15 nm, 20 nm, 30 nm, 40 nm, or 50 nm. The application principle of the beneficial effect in this case is the same as the application principle of the beneficial effect of the first doped semiconductor portion having a thickness greater than or equal to 50 nm and less than or equal to 200 nm as described above, and will not be repeated here.

[0125] In terms of the formation position, Figure 1 and Figure 2 As shown, the second doped semiconductor portion 13 may be directly disposed on the second region 16 and extend to cover the first doped semiconductor portion 12 in the overlapping region 17. Alternatively, as shown in FIG. Figure 3As shown, the above-mentioned back-contact battery may further include a second interface passivation layer 27, which is located between the second region 16 and the second doped semiconductor portion 13 on the first surface and extends between the second doped semiconductor portion and the first doped semiconductor portion. In this case, the passivation contact structure formed by the second interface passivation layer 27 and the portion of the second doped semiconductor portion 13 located on the second region 16 can achieve selective collection of carriers and reduce the carrier recombination rate in the second region 16 on the first surface of the semiconductor substrate 11. The material and thickness of the second interface passivation layer 27 can be set according to the material of the second doped semiconductor portion 13 and actual requirements, and no specific limitation is made here. For example: when the material of the second doped semiconductor portion is doped polysilicon, the second interface passivation layer is a tunneling passivation layer. Another example: when the material of the second doped semiconductor portion 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.

[0126] Regarding the thickness of the second interface passivation layer, since the thickness of the second interface passivation layer will affect its own transmission resistance and passivation effect, and thus affect the forward leakage loss and reverse breakdown voltage of the back-contact battery, the thickness of the second interface passivation layer can be determined according to the requirements for the forward leakage loss and reverse breakdown voltage of the back-contact battery in the actual application scenario, and no specific limitation is made here.

[0127] Exemplarily, the thickness of the above-mentioned second interface passivation layer can be greater than or equal to 2 nm and less than or equal to 20 nm. For example: the thickness of the second interface passivation layer can be 2 nm, 5 nm, 8 nm, 10 nm, 12 nm, 15 nm, 18 nm, or 20 nm, etc. In this case, based on this, when the thickness of the second interface passivation layer is within the above range, it is beneficial to prevent the poor passivation effect on the second region due to the small thickness of the second interface passivation layer, and ensure a low carrier recombination rate on the surface of the second region. It can also prevent the large transmission resistance of the second interface passivation layer due to its large thickness, resulting in a low carrier collection efficiency of the second doped semiconductor portion during the normal operation of the back-contact battery and a small decrease in the reverse breakdown voltage when the back-contact battery is shaded, which is further beneficial to achieving a balance between the reverse breakdown voltage and the working efficiency of the back-contact battery.

[0128] In addition, the doping concentration of the dopant in the first doped semiconductor part will affect its own conductivity. Specifically, within a certain range, the higher the doping concentration of the dopant in the first doped semiconductor part, the higher the conductivity of the first doped semiconductor part; on the contrary, the lower the doping concentration of the dopant in the first doped semiconductor part, the lower the conductivity of the first doped semiconductor part. As for the above-mentioned second interface passivation layer, as mentioned above, the thickness of the second interface passivation layer is related to its own passivation effect and transmission resistance. When the thickness of the second interface passivation layer is small, in the reverse leakage region, the leakage current between the first doped semiconductor part and the second doped semiconductor part is larger. When the thickness of the second interface passivation layer is larger, the leakage loss in the forward voltage region of the back contact battery is lower, but the transmission resistance of the second interface passivation layer is larger. Based on this, the thickness of the second interface passivation layer that matches it can also be determined according to the range of the doping concentration of the dopant in the first doped semiconductor part in the actual application scenario.

[0129] For example, when the doping concentration of the dopant in the first doped semiconductor portion is greater than or equal to 1E19 cm -3 , and less than or equal to 5E19cm -3 When the thickness of the second interface passivation layer is greater than or equal to 5 nm and less than or equal to 15 nm, the thickness of the second interface passivation layer can be greater than or equal to 5 nm and less than or equal to 15 nm. -3 , and less than or equal to 5E19cm -3 When , the thickness of the second interface passivation layer can be 5nm, 8nm, 10nm, 12nm, 14nm or 15nm, etc.

[0130] Alternatively, when the doping concentration of the dopant in the first doped semiconductor portion is greater than 5E19 cm -3 , and less than or equal to 1E20cm -3 When the thickness of the second interface passivation layer is greater than or equal to 6 nm and less than or equal to 17 nm, the thickness of the second interface passivation layer can be greater than or equal to 6 nm and less than or equal to 17 nm. -3 , and less than or equal to 1E20cm -3 When the thickness of the second interface passivation layer is 5 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm or 17 nm, etc.

[0131] Alternatively, when the doping concentration of the dopant in the first doped semiconductor portion is greater than 1E20 cm -3 , and less than or equal to 5E20cm -3 When the thickness of the second interface passivation layer is greater than or equal to 7 nm and less than or equal to 20 nm, the thickness of the second interface passivation layer can be greater than or equal to 7 nm and less than or equal to 20 nm. -3 , and less than or equal to 5E20cm-3 When the thickness of the second interface passivation layer is 7 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 16 nm, 18 nm or 20 nm, etc.

[0132] It is worth noting that the back-contact battery provided in the embodiment of the present invention is provided with a second interface passivation layer with a corresponding thickness according to the different doping concentrations of the dopant in the first doped semiconductor part, so as to achieve reasonable regulation of the working efficiency and reverse breakdown voltage of the back-contact battery, thereby ensuring that the back-contact battery has high working performance and working reliability.

[0133] In addition, when the back contact battery includes a first interface passivation layer and a second interface passivation layer, the first interface passivation layer and the first doped semiconductor portion constitute a first passivation contact structure, and the second interface passivation layer and the second doped semiconductor portion constitute a second passivation contact structure.

[0134] Among them, the passivation contact types of the first passivation contact structure and the second passivation contact structure can be the same. For example: the first passivation contact structure and the second passivation contact structure are both tunneling passivation contact structures or heterogeneous contact structures. Alternatively, the passivation contact types of the first passivation contact structure and the second passivation contact structure can also be different. For example: one of the first passivation contact structure and the second passivation contact structure is a tunneling passivation contact structure, and the other is a heterogeneous contact structure. In this case, when the passivation contact types of the first passivation contact structure and the second passivation contact structure are different, the passivation contact types of the first passivation contact structure and the second passivation contact structure can be adjusted separately according to different actual application scenario requirements to improve the applicability of the back contact battery provided by the embodiment of the present invention in different application scenarios.

[0135] Secondly, the thermal stability of the first passivation contact structure described above can be greater than that of the second passivation contact structure. In this case, during the actual manufacturing process, the first passivation contact structure is formed in the first region and the overlapping region. After the second passivation contact structure is formed as a whole layer, it is usually necessary to use a laser treatment process to pattern the mask material provided as a whole layer to form a mask layer for selectively etching the second passivation contact structure. In order to process all parts of the mask material corresponding to the first region, the heat of the laser radiation for processing will be conducted to the first passivation contact structure. Since the heat of the laser is relatively high, when the first passivation contact structure has high thermal stability, the influence of the laser radiation heat on the first passivation contact structure can be reduced, or even the first passivation contact structure will not be affected by the heat of the laser radiation, thus improving the yield of the back contact battery. The part of the second passivation contact structure corresponding to the first region needs to be removed, and the precision of the laser treatment process is relatively high. Therefore, the parts of the second passivation contact structure corresponding to the overlapping region and the second region will not be affected by heat, or will be less affected by heat. At this time, the manufacturing process has a lower requirement for the thermal stability of the second passivation contact structure, and the thermal stability of the second passivation contact structure can be set to be lower than that of the first passivation contact structure.

[0136] Of course, the first passivation contact structure and the second passivation contact structure can also have substantially the same thermal stability. Or, during the actual manufacturing process, if a laser treatment process is not used to pattern the mask material, but other low-temperature processes are used to selectively etch the mask material and the second passivation contact structure, the first passivation contact structure can also have relatively low thermal stability.

[0137] As for the specific types of the first passivation contact structure and the second passivation contact structure, they can be determined according to actual requirements and are not specifically limited here.

[0138] Exemplarily, the first passivation contact structure can be a tunneling passivation contact structure. In this case, since amorphous silicon material is prone to form polycrystalline silicon or single-crystalline silicon at high temperatures, and the chemical properties of tunneling passivation material and polycrystalline silicon are relatively stable at high temperatures, compared with the heterojunction contact structure, the tunneling passivation contact structure is less sensitive to laser thermal damage at high temperatures, which can reduce the influence on the passivation effect during the laser treatment process, further increase the process window, and reduce the process difficulty. In addition, in the actual manufacturing process, the manufacturing cost of the heterojunction contact structure is higher than that of the tunneling passivation contact structure. Moreover, the tunneling passivation contact structure can be realized by various processes such as low-pressure chemical vapor deposition, plasma chemical vapor deposition, physical chemical vapor deposition, or plasma-enhanced atomic layer deposition, which is easier to be compatible with the back-contact cell process, while the heterojunction contact structure needs to be manufactured by using a plate-type plasma chemical vapor deposition device with a lower support formation temperature. Based on this, when the first passivation contact structure is a tunneling passivation contact structure, it is beneficial to reduce the manufacturing cost, reduce the investment in plate-type plasma chemical vapor deposition equipment, and save the production site area.

[0139] Exemplarily, the second passivation contact structure can be a heterojunction contact structure. In this case, the heterojunction contact structure has a better passivation effect than the tunneling passivation contact structure. Therefore, when the second passivation contact structure is a heterojunction contact structure, the carrier recombination rate at the interface between the semiconductor substrate and the second interfacial passivation layer can be further reduced, which is beneficial to improving the photoelectric conversion efficiency of the back-contact cell. Specifically, the material of the intrinsic semiconductor passivation layer in the heterojunction contact structure can include at least one of intrinsic amorphous silicon, intrinsic microcrystalline silicon, and intrinsic nanocrystalline silicon. The material of the doped semiconductor layer in the heterojunction contact structure can include at least one of doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon.

[0140] It should be noted that the materials of the passivation contact structures of different passivation contact types are different, and the conductive characteristics of doped semiconductor materials of different conductive types are different. Therefore, the conductive type of the second passivation contact structure can be determined according to the passivation contact types of the first passivation contact structure and the second passivation contact structure.

[0141] Preferably, when the first passivation contact structure is a tunneling passivation contact structure and the second passivation contact structure is a heterojunction contact structure, the conductive type of the first passivation contact structure is N-type, and the second passivation contact structure is P-type. In this case, compared with P-type doped amorphous silicon or P-type doped microcrystalline silicon materials, the contact resistance between P-type doped polycrystalline silicon materials and the electrode is higher and the field passivation effect is worse. Therefore, when the conductive type of the tunneling passivation contact structure is set to N-type and the conductive type of the heterojunction contact structure is set to P-type, the field passivation effect of the first tunneling passivation contact structure can be further improved, and at the same time, the contact resistance between the first tunneling passivation contact structure and the electrode can be reduced, which is beneficial to improving the electrical performance of the back-contact cell.

[0142] For the above-mentioned transparent conductive layer, the embodiments of the present invention do not specifically limit the material and thickness of the transparent conductive layer. Exemplarily, the material of the transparent conductive layer may include at least one of tin-doped indium oxide, aluminum-doped zinc oxide, indium tin oxide, indium tungsten oxide, indium molybdenum oxide, indium cerium oxide, and indium hydroxide.

[0143] Exemplarily, the thickness of the transparent conductive layer may be greater than or equal to 10 nm and less than or equal to 100 nm.

[0144] As for the insulating groove provided in the transparent conductive layer, the insulating groove is used to physically insulate the part of the transparent conductive layer corresponding to the first region from the part of the transparent conductive layer corresponding to the second region. Specifically, since the part of the transparent conductive layer corresponding to the first region is ohmically connected to the first electrode, and the part of the transparent conductive layer corresponding to the second region is ohmically connected to the second electrode, these two parts of the transparent conductive layer cannot be directly electrically connected, that is, these two parts of the transparent conductive layer must be physically insulated, that is, not in contact. Based on this, it can be understood that, in order to prevent short circuits, the two end positions of the insulating groove may both be located within the overlapping region, or one end position along the first direction may be located outside the overlapping region (of course, it can be understood that the reverse leakage region is excluded, because in the reverse leakage region, the transparent conductive layer must extend from the second region into the overlapping region).

[0145] In addition, as Figures 1 to 3 shown, the above-mentioned insulating groove 18 may only penetrate the transparent conductive layer 14. Or, as Figure 4 shown, when the second doped semiconductor part 13 has a relatively low resistivity (such as the resistivity of the second doped semiconductor part 13 is less than or equal to 0.01 Ω·cm, specifically, such as the second doped semiconductor part 13 is a doped polysilicon layer and / or a doped single crystal silicon layer), the above-mentioned insulating groove 18 not only needs to penetrate the transparent conductive layer 14, but also needs to penetrate at least the second doped semiconductor part 13 to prevent short circuits caused by the parts of the transparent conductive layer 14 corresponding to the first region 15 and the second region 16 being electrically connected through the second doped semiconductor part 13 continuously provided in the overlapping region 17. If there is the above-mentioned second interface passivation layer, generally, the second interface passivation layer does not need to be disconnected at the insulating groove; of course, in some processes, the second doped semiconductor part 13 and the second interface passivation layer can also be disconnected together in the same process step).

[0146] As for the width of the insulating groove along the first direction, its range will not only affect the electrical insulation effect between the portions of the transparent conductive layer corresponding to the first area and the second area, but also affect the width of the first transparent conductive portion along the first direction on the common and overlapping areas, thereby affecting the leakage loss and reverse breakdown voltage of the back contact battery. Therefore, it is set according to actual needs, as long as the ratio of the width W1 of the first transparent conductive portion in the first direction to the width W2 of the overlapping area in the first direction can be greater than or equal to 10% and less than or equal to 90%.

[0147] Specifically, the ratio of the width W1 of the first transparent conductive portion in the first direction to the width W2 of the overlapping region in the first direction can be any value greater than or equal to 10% and less than or equal to 90%. For example, the ratio of W1 to W2 can be 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90%.

[0148] Secondly, the cross-sectional area of the insulation trench can be the same in different regions along the thickness of the semiconductor substrate. Alternatively, the cross-sectional area of the insulation trench can gradually decrease as it approaches the semiconductor substrate. Specifically, when the cross-sectional area of the insulation trench gradually decreases as it approaches the semiconductor substrate, it can decrease linearly, parabolically, or in other ways, such as by a parabola. With this arrangement, the cross-sectional area at the bottom of the insulation trench is smaller than the cross-sectional area at the opening of the insulation trench. In this case, the thickness of the transparent conductive layer near the end of the insulation trench gradually increases as it moves away from the insulation trench. Based on this, especially for the reverse leakage region, the leakage current flows from the edge of the transparent conductive layer to the corresponding electrode. In this case, the leakage current density at the edge of the transparent conductive layer is relatively low, while almost all leakage current flows through the portion of the transparent conductive layer away from the edge region. Therefore, the leakage current density in the portion of the transparent conductive layer away from the edge region is relatively high. In this case, when the thickness of the transparent conductive layer near the end of the insulation trench gradually increases as it moves away from the insulation trench, the thickness of the portion of the transparent conductive layer away from the edge region is relatively high, which is more conducive to the transmission of leakage current and further reduces the risk of hot spots in back-contact batteries.

[0149] Furthermore, the thickness of the transparent conductive layer along the first direction can be uniform across regions where the orthographic projection on the first surface does not overlap with the orthographic projection of the insulating trench on the first surface. This facilitates greater thickness across regions along the first direction of the transparent conductive layer away from its edge regions. This not only facilitates the transmission of leakage current when the back-contact cell is blocked, but also facilitates the extraction of photocurrent generated by the back-contact cell in the forward voltage region, further improving the operating performance of the back-contact cell and reducing the risk of hot spots.

[0150] Alternatively, in the transparent conductive layer, the thicknesses of the regions along the first direction in the portion where the orthographic projection on the first surface does not overlap with the orthographic projection of the insulating groove on the first surface may also be the same. For example, when the conductivities of the first doped semiconductor portion and the second doped semiconductor portion are different, the thickness of the transparent conductive layer disposed on one of the first doped semiconductor portion and the second doped semiconductor portion where the conductivities cross may be greater than the thickness of the transparent conductive layer disposed on the other.

[0151] Secondly, as Figures 1 to 4 shown, the portion where the transparent conductive layer 14 extends from the first region 15 into the overlapping region 17 is defined as the second transparent conductive portion 20. It can be understood that under the spacing action of the insulating groove 18, the leakage current will only pass through the first doped semiconductor portion 12 in the reverse leakage region and be conducted to the first transparent conductive portion 19 with a conductivity type opposite to that of the first doped semiconductor portion 12 through the second doped semiconductor portion 13. Therefore, the presence of the second transparent conductive portion 20 has a low or even no influence on the reverse breakdown voltage. However, the first transparent conductive portion 19, the second transparent conductive portion 20, and the insulating groove 18 are all disposed in the overlapping region 17. In order to separate the portions of the transparent conductive layer 14 corresponding to the first region 15 and the second region 16, the width of the insulating groove 18 in the first direction needs to be greater than or equal to the minimum spacing for preventing leakage. Based on this, the width of the second transparent conductive portion 20 in the first direction will indirectly affect the leakage loss and the reverse breakdown voltage of the back contact battery. Therefore, the width of the second transparent conductive portion 20 in the first direction can be set according to actual requirements, and no specific limitation is made here.

[0152] Exemplarily, the width of the second transparent conductive portion in the first direction is W3, and the ratio of W3 to W2 may be less than or equal to 80%. For example, the width of the second transparent conductive portion in the first direction is W3, and the ratio of W3 to W2 may be 0, 10%, 20%, 30%, 40%, 50%, 60%, 70%, or 80%, etc. In this case, the width of the second transparent conductive portion in the first direction is W3, and the ratio of W3 to W2 has a relatively large optional range. By adjusting the width of the second transparent conductive portion in the first direction, the width of the first transparent conductive portion in the first direction can be indirectly adjusted, which is further beneficial to balancing the reverse breakdown voltage and the working efficiency of the back contact battery.

[0153] In the actual application process, embodiments of the present invention can adjust the contact area between the first transparent conductive part and the second doped semiconductor part by adjusting the ratio of the width W1 of the first transparent conductive part in the first direction to the width W2 of the overlapping area in the first direction, thereby realizing the regulation of the forward leakage loss and the reverse breakdown voltage of the back-contact battery. The size of the contact area between the first transparent conductive part and the second doped semiconductor part is not only related to the width W1 of the first transparent conductive part in the first direction, but also related to the distribution of the reverse leakage area in the second direction.

[0154] Specifically, as Figure 5 shown, the above-mentioned reverse leakage area can be continuously distributed in the second direction, and the second direction intersects with the first direction. In this case, the extension length of the first transparent conductive part 19 in the second direction is fixed, and the contact area between the first transparent conductive part 19 and the second doped semiconductor part is related to W1. Secondly, at this time, the part of the transparent conductive layer extending from the second region into the overlapping region (i.e., the first transparent conductive part 19) can be continuously distributed in the second direction, so that the pattern for selectively etching the transparent conductive material (used to manufacture the above-mentioned transparent conductive layer) provided on the first doped semiconductor part and the second doped semiconductor part as a whole (only the pattern corresponding to the notch of the insulating groove) is relatively simple, which is beneficial to reducing the patterning difficulty of the back-contact battery. At the same time, when the reverse leakage area is continuously distributed in the second direction, the leakage path between the first doped semiconductor part and the second doped semiconductor part is more evenly distributed, so that the heat generated when the back-contact battery is blocked is evenly distributed over the entire battery area, further improving the anti-burning ability of the back-contact battery. It should be noted that the above-mentioned second direction can be any direction parallel to the first plane and different from the first direction. Preferably, the second direction is orthogonal to the first direction.

[0155] Or, as Figure 6As shown, the reverse leakage region can also be distributed discontinuously along the second direction, and the second direction intersects the first direction. Furthermore, along the second direction, the first transparent conductive portion 19 has a continuous region 21 and a discontinuous region 22. That is, the continuous region of the first transparent conductive portion 19 is the reverse leakage region, while the discontinuous region is the region between two adjacent reverse leakage regions. In this case, another embodiment is provided for the distribution of the first transparent conductive portion 19 along the second direction. In this case, the contact area between the first transparent conductive portion 19 and the second doped semiconductor portion is not only related to W1, but also to the length of the continuous region 21 and the discontinuous region 22 of the first transparent conductive portion 19 along the second direction. Based on this, not only can the reverse breakdown voltage and forward leakage loss of the back-contact battery be regulated by adjusting the width of the first transparent conductive portion 19 along the first direction, but the reverse breakdown voltage and forward leakage loss of the back-contact battery can also be regulated by adjusting the length of the continuous region 21 and the discontinuous region 22 of the first transparent conductive portion 19 along the second direction, thereby improving the applicability of the back-contact battery provided by the embodiment of the present invention in different application scenarios. It should be noted that the above-mentioned second direction can be any direction parallel to the first surface and different from the first direction. Preferably, the second direction is orthogonal to the first direction.

[0156] In the case of the above content, the ratio of W1 and W2 that affect the contact area between the first transparent conductive part and the second doped semiconductor part, as well as the distribution of the reverse leakage area along the second direction can be comprehensively adjusted according to actual needs, so as to achieve precise control of the forward leakage loss and reverse breakdown voltage of the back-contact battery in actual application scenarios.

[0157] For example, when the reverse leakage region is continuously distributed along the second direction, the ratio of W1 to W2 can be greater than or equal to 10% and less than or equal to 70%. In this case, the reduction in reverse breakdown voltage caused by a smaller ratio of W1 to W2, which results in a smaller contact area between the first transparent conductive portion and the second doped semiconductor portion, can be prevented. Furthermore, the forward leakage loss caused by a larger ratio of W1 to W2, which results in a larger contact area between the first transparent conductive portion and the second doped semiconductor portion, can be prevented. This further helps achieve a balance between the reverse breakdown voltage and operating efficiency of the back-contact cell.

[0158] Exemplarily, when the reverse leakage region is intermittently distributed along the second direction, the ratio of the length of the discontinuous region to the length of the continuous region along the second direction may be less than or equal to 90%. For example, the ratio of the length of the discontinuous region to the length of the continuous region may be 1%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% or 90%, etc. In this case, when the back contact battery provided by an embodiment of the present invention is set in an installation environment with fewer obstructions such as bird droppings, leaves or dust, the ratio of the length of the discontinuous region to the length of the continuous region may be set within a larger range to increase the proportion of the discontinuous region in the reverse leakage region, thereby facilitating the reduction of the leakage loss of the back contact battery in the forward voltage region and ensuring that the back contact battery has a higher working efficiency. When the back-contact battery provided by the embodiment of the invention is installed in an environment with many obstructions such as bird droppings, leaves, or sand and dust, the ratio of the length of the discontinuous region to the length of the continuous region can be set within a smaller range to increase the proportion of the continuous region within the reverse leakage area, thereby helping to reduce the reverse breakdown voltage of the back-contact battery and ensure that the back-contact battery has a lower risk of hot spots. Thus, it can be seen that when the ratio of the length of the discontinuous region to the length of the continuous region along the second direction is less than or equal to 90%, the length of the discontinuous region and the length of the continuous region can be set according to different environmental requirements, thereby improving the applicability of the back-contact battery provided by the embodiment of the invention in different practical application scenarios.

[0159] For example, when the reverse leakage region is intermittently distributed along the second direction, the ratio of W1 to W2 is greater than or equal to 20% and less than or equal to 90%. This configuration can improve the applicability of the back-contact battery provided by the present invention in different practical application scenarios. Specifically, the application principle of the beneficial effect in this case is similar to the application principle of the beneficial effect of the ratio of W1 to W2 being greater than or equal to 10% and less than or equal to 70% when the reverse leakage region is continuously distributed along the second direction, as described above, and will not be repeated here.

[0160] For example, when the reverse leakage region is intermittently distributed along the second direction, the ratio of the width of the continuous region to the length of the continuous region is greater than or equal to 1:500 and less than or equal to 5:1. Such an arrangement can improve the applicability of the back-contact battery provided by the present invention in different practical application scenarios. Specifically, the application principle of the beneficial effect in this case is similar to the application principle of the beneficial effect of the ratio of W1 to W2 being greater than or equal to 10% and less than or equal to 70% when the reverse leakage region is continuously distributed along the second direction, as described above, and will not be repeated here.

[0161] Secondly, in the actual application process, such as Figures 5 to 7 As shown in FIG, the portion of the transparent conductive layer disposed in the second region is defined as the third transparent conductive portion 23. Based on this, when the reverse leakage region is discontinuously distributed along the second direction, as shown in FIG.Figure 6 As shown, the third transparent conductive portion 23 may completely cover the portion of the second doped semiconductor portion corresponding to the second region. Figure 7 As shown, the portion of the third transparent conductive portion 23 corresponding to the discontinuity region 22 may also be provided with a notch 24. In this case, the second doped semiconductor portion is not only disposed on the second region but also extends to cover the first doped semiconductor portion in the overlapping region. In this case, the second doped semiconductor portion can be located not only on the side of the first doped semiconductor portion in the overlapping region facing away from the semiconductor substrate, but also on the sidewall of the first doped semiconductor portion in the overlapping region. Furthermore, the transparent conductive layer is disposed on the first and second doped semiconductor portions. In this case, the transparent conductive layer can contact the second doped semiconductor portion disposed on the sidewall of the first doped semiconductor portion in the overlapping region. In this case, when the portion of the transparent conductive layer disposed in the second region (i.e., the third transparent conductive portion 23) corresponding to the portion of the discontinuous region 22 is provided with a notch 24, this ensures that the third transparent conductive portion 23 will not be electrically connected to the second doped semiconductor portion in the discontinuous region 22. This ensures that the contact area between the second doped semiconductor portion and the transparent conductive layer in the reverse leakage region can be effectively adjusted by adjusting the length of the discontinuous region 22 and the continuous region 21 of the first transparent conductive portion 19 along the second direction, thereby achieving precise control of the reverse breakdown voltage and forward leakage loss of the back-contact cell. Furthermore, in actual application and manufacturing processes, it is necessary to selectively etch the first transparent conductive portion 19 to achieve a discontinuous distribution of the reverse leakage region along the second direction. Based on this, when the portion of the third transparent conductive portion 23 adjacent to the first transparent conductive portion 19 corresponding to the discontinuity zone 22 is provided with a notch 24, there is no need to strictly control the etching accuracy in order to achieve the above-mentioned selective etching in order to precisely stop at the junction of the first transparent conductive portion 19 and the third transparent conductive portion 23 during the etching process of the first transparent conductive portion 19, which is beneficial to reducing the manufacturing difficulty of the back contact battery.

[0162] Specifically, when the first transparent conductive portion has multiple discontinuous areas along the second direction, the third transparent conductive portion may be provided with a notch only in the portion corresponding to the individual discontinuous areas, or the third transparent conductive portion may also be provided with a notch in the portion corresponding to each discontinuous area. As for the size of the notch, it can be understood that in the transparent conductive layer, the portion provided on the side of the second doped semiconductor portion away from the semiconductor substrate (i.e., the third transparent conductive portion) needs to guide the carriers collected by the portion of the second doped semiconductor portion corresponding to the second region to the corresponding electrode when the back contact battery is in a working state, and can reduce the contact barrier between the second doped semiconductor portion and the corresponding electrode, thereby reducing the carrier transmission loss. Based on this, the width of the notch along the first direction can be determined according to the requirements for the control of carrier transmission loss and leakage current in actual application scenarios, as well as the actual manufacturing process, and is not specifically limited here.

[0163] Exemplarily, the width of the notch in the first direction may be less than or equal to 100 μm. For example, the width of the notch in the first direction may be 1 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 80 μm or 100 μm, etc. In this case, based on this, when a notch is provided in the portion of the third transparent conductive portion corresponding to the spacer, the carriers collected in the portion of the second doped semiconductor portion corresponding to the notch need to pass through the adjacent portion before they can be transmitted to the third transparent conductive portion. At this time, the transmission loss of the carriers collected in the portion of the second doped semiconductor portion corresponding to the notch is relatively high. In this case, when the width of the notch in the first direction is less than or equal to 100 μm, the range of the notch is relatively small, which is conducive to reducing the difficulty of selective etching while controlling the transmission loss of the carriers collected in the second doped semiconductor portion within a certain range, thereby ensuring that the back contact cell has a high photoelectric conversion efficiency.

[0164] In one example, Figures 1 to 4 As shown, the back-contact cell further includes a first electrode 25 disposed on a portion of the transparent conductive layer 14 corresponding to the second region 16, and a second electrode 29 disposed on a portion of the transparent conductive layer 14 corresponding to the first region 15, to respectively conduct carriers collected by the portions of the transparent conductive layer 14 corresponding to the first region 15 and the second region 16. The materials of the first electrode 25 and the second electrode 29 may be any conductive material such as silver, aluminum, copper, titanium, and nickel.

[0165] In one example, Figure 3 As shown, the back-contact cell further includes a surface passivation layer 28 disposed on the second surface of the semiconductor substrate 11 to passivate the second surface of the semiconductor substrate 11 and reduce the carrier recombination rate on the second surface. The structure and material of the surface passivation layer 28 can be determined based on at least the requirements for the carrier recombination rate on the second surface in actual application scenarios and the actual manufacturing process, and are not specifically limited here.

[0166] Exemplarily, the surface passivation layer may include an intrinsic semiconductor passivation layer and a silicon nitride passivation layer stacked in sequence along the thickness direction of the semiconductor substrate on the side of the second surface. The material of the intrinsic semiconductor passivation layer includes amorphous silicon and / or microcrystalline silicon. In this case, the intrinsic semiconductor passivation layer included in the surface passivation layer can be formed simultaneously when the interface passivation layer included in the heterogeneous contact structure is manufactured on the side of the first surface. The silicon nitride passivation layer included in the surface passivation layer can be formed simultaneously when the mask material for realizing the second passivation contact structure is manufactured on the side of the first surface. There is no need to add additional operating steps to form the surface passivation layer, which is beneficial to improving the manufacturing efficiency of the back contact battery.

[0167] The present invention also provides the following seven specific examples and two comparative examples to illustrate the working performance of the back contact battery provided by the present invention:

[0168] Example 1

[0169] First, the silicon wafer is polished and cleaned. Specifically, it is placed in a tank-type polishing and cleaning machine for polishing to remove the damaged layer on the wafer. The polishing morphology of the first and second surfaces of the silicon wafer is regulated by controlling the temperature, time, and chemical concentration.

[0170] Next, the first deposition operation is performed. Specifically, a tunneling silicon oxide layer and an intrinsic polysilicon layer are sequentially deposited on one side of the first surface of the silicon wafer. Both the tunneling silicon oxide layer and the intrinsic polysilicon layer are deposited using a low-pressure chemical vapor deposition (LPCVD) furnace. The thickness of the tunneling silicon oxide layer is 1.4nm, and the thickness of the intrinsic polysilicon is 120nm.

[0171] Next, a phosphorus diffusion process is performed. Specifically, intrinsic polysilicon is doped by high-temperature diffusion to form an N-type polysilicon layer, and a phosphorus-silicate glass layer is formed on the side of the N-type polysilicon layer facing away from the silicon wafer.

[0172] Next, a first wet etching operation is performed. Specifically, this step removes the phosphosilicate glass layer using an HF solution with a concentration of 5% and an etching time of 2 minutes.

[0173] Next, a second deposition operation is performed, using a plasma chemical vapor deposition device to deposit a silicon nitride layer with a thickness of 80 nm and a refractive index of 2.0 on one side of the first surface of the silicon wafer.

[0174] Next, a first laser etching operation is performed. Specifically, a laser etching process is used to remove the portion of the silicon nitride layer corresponding to the second region and the portion of the N-type doped polysilicon layer corresponding to the second region. The laser used may be a 532 picosecond laser.

[0175] Next, a second wet etching operation is performed to form a pyramid texture structure on the surface of the second region and the second side, while removing the silicon nitride layer deposited in the second deposition operation.

[0176] Next, a third deposition operation was performed. Specifically, a chemical vapor deposition process was used to sequentially form an intrinsic silicon layer and a P-type silicon layer on one side of the first side of the silicon wafer. The intrinsic silicon layer had a thickness of 8 nm. The P-type silicon layer had a thickness of 15 nm and a crystallinity of 5%. Simultaneously, in this step, an intrinsic silicon layer and an anti-reflection layer were deposited on the second side of the silicon wafer. The anti-reflection layer was a 75 nm thick silicon nitride layer.

[0177] Next, a second laser etching operation and a second wet etching operation are performed. Specifically, a laser etching process is used to remove the portion of the intrinsic silicon layer corresponding to the first region and the portion of the P-type silicon layer corresponding to the first region. The laser used is a 532 picosecond laser. The semi-finished product is then placed face-up on its second side using a chain device and protected by a water film. The first side of the semi-finished product is then exposed to an HF solution to remove the oxide layer formed during the doping process of the P-type silicon layer and the silicon nitride layer that was deposited onto the first side during the third deposition operation.

[0178] Next, a transparent conductive layer is entirely deposited on one side of the first surface. The transparent conductive layer is an indium tin oxide layer with a thickness of 50 nm.

[0179] Next, the transparent conductive layer connecting the N and P regions is isolated, while the intrinsic silicon layer and P-type silicon layer above the overlapped region are also isolated, achieving complete structural isolation between the two polarity regions. This isolation is achieved using an etching slurry. The etched pattern ensures that at least a portion of the transparent conductive layer overlaps the P region and the overlapped region, achieving physical insulation between the N and P regions. The transparent conductive layer overlapping the P region and the overlapped region is evenly distributed across the entire cell area, with a W1 to W2 ratio of 90%.

[0180] Then, metallization is performed. Specifically, metal silver electrodes are prepared on top of the two transparent conductive layers to collect carriers and interconnect the electrodes of the entire battery.

[0181] Example 2

[0182] The back contact cell provided in Example 2 has the same configuration as the back contact cell provided in Example 1 except that the ratio of W1 to W2 is 70%.

[0183] Example 3

[0184] The back contact cell provided in Example 3 has the same configuration as the back contact cell provided in Example 1 except that the ratio of W1 to W2 is 50%.

[0185] Example 4

[0186] The back contact cell provided in Example 4 has the same configuration as the back contact cell provided in Example 1 except that the ratio of W1 to W2 is 40%.

[0187] Example 5

[0188] The back contact cell provided in Example 5 has the same configuration as the back contact cell provided in Example 1 except that the ratio of W1 to W2 is 10%.

[0189] Example 6

[0190] The back contact cell provided in Example 6 has the same configuration as the back contact cell provided in Example 4 except that the crystallization rate of the P-type silicon layer is 0.

[0191] Example 7

[0192] The back contact cell provided in Example 7 has the same configuration as the back contact cell provided in Example 4 except that the crystallization rate of the P-type silicon layer is 10%.

[0193] Comparative Example 1

[0194] The back contact cell provided in Comparative Example 1 has the same configuration as the back contact cell provided in Example 1 except that the ratio of W1 to W2 is 95%.

[0195] Comparative Example 2

[0196] The back contact cell provided in Comparative Example 2 has the same configuration as the back contact cell provided in Example 1 except that the ratio of W1 to W2 is 5%.

[0197] Table 1 Test parameters of back contact cells provided in Examples 1 to 7 and Comparative Examples 1 and 2

[0198]

[0199] It should be noted that the data in Table 1 are obtained by selecting 10,000 back-contact batteries as samples from each back-contact battery product line corresponding to Examples 1 to 7, and Comparative Examples 1 and 2. The efficiency data in the table are obtained by performing efficiency tests on 10,000 samples under each embodiment and calculating the average value. Among them, the back-contact batteries with an efficiency greater than 26% in the 10,000 samples under each embodiment are defined as batteries with efficiency grade A, and the efficiency grade A rate is calculated by dividing the number of batteries with efficiency grade A under each embodiment by 10,000. In addition, 10% of the 10,000 samples under each embodiment are subjected to random reverse breakdown voltage tests, and the reverse breakdown voltage data in the table are calculated by calculating the average value. Among them, the back-contact batteries with a reverse breakdown voltage less than 11V in the 10,000 samples under each embodiment are defined as batteries with hot spot reliability grade A, and the hot spot reliability grade A rate is calculated by dividing the number of batteries with hot spot reliability grade A under each embodiment by 10,000.

[0200] In the above case, it can be seen from the data in Table 1 that the larger the ratio of the width W1 of the first transparent conductive portion along the first direction to the width W2 of the overlapping region along the first direction, the lower the reverse breakdown voltage of the back-contact battery. When the ratio of W1 to W2 is 95%, although the hot spot reliability A-level rate of the back-contact battery is high, because the leakage loss in the forward voltage region is also high, the efficiency A-level rate of the back-contact battery corresponding to Comparative Example 1 is very low and does not meet the operating requirements. Conversely, when the ratio of W1 to W2 is 5%, although the efficiency A-level rate of the back-contact battery is high, because the leakage current in the reverse leakage region is small, the hot spot reliability A-level rate of the back-contact battery corresponding to Comparative Example 2 is very low and does not meet the operating requirements.

[0201] In addition, it can be seen from the data in Table 1 that the reverse breakdown voltage of the back-contact cell decreases with the increase of the crystallization rate of the second doped semiconductor portion. However, within a certain range, the efficiency and fill factor of the back-contact cell increase with the increase of the crystallization rate of the second doped semiconductor portion. When the crystallization rate of the second doped semiconductor portion increases to a certain value, the efficiency and fill factor of the back-contact cell decrease with the increase of the crystallization rate of the second doped semiconductor portion.

[0202] In a second aspect, an embodiment of the present invention provides a photovoltaic module, which includes a back-contact cell provided by the first aspect and various implementations thereof.

[0203] The beneficial effects of the second aspect and its various implementations in the embodiments of the present invention can be analyzed with reference to the beneficial effects of the first aspect and its various implementations, and will not be repeated here.

[0204] In the third aspect, the present invention provides a method for manufacturing a back contact battery. Figures 8 to 20 The manufacturing process is described in detail with reference to the cross-sectional view of the operation shown. Specifically, the manufacturing method of the back contact battery includes the following steps:

[0205] First, if Figure 8 As shown, a semiconductor substrate 11 is provided. The semiconductor substrate 11 includes a first surface and a second surface opposite to each other. The first surface includes a first region 15, a second region 16, and an overlapping region 17 between the first region 15 and the second region 16. The first region 15, the overlapping region 17, and the second region 16 are arranged along a first direction.

[0206] Specifically, the material of the semiconductor substrate, and the distribution of the first region, the second region, and the overlapping region on one side of the first surface can be referred to above and will not be described in detail here.

[0207] Next, if Figure 11As shown, a first doped semiconductor portion is formed in the first region 15 and the overlapping region 17. The first doped semiconductor portion may be disposed on the first region 15 and the overlapping region 17, or may be disposed within the first region 15 and the overlapping region 17.

[0208] Exemplarily, as Figure 9 shown, a first doped semiconductor portion disposed entirely on or within the first surface may be formed first. Next, as Figure 10 shown, an insulating mask layer 30 is formed on the portions of the first doped semiconductor portion 12 corresponding to the first region 15 and the overlapping region 17. Next, as Figure 11 shown, under the protection of the insulating mask layer 30, the portions of the first doped semiconductor portion 12 corresponding to the second region 16 are removed. Then, as Figure 13 shown, the insulating mask layer is removed.

[0209] In an actual manufacturing process, a first doped semiconductor portion disposed entirely on or within the first surface may be formed by processes such as diffusion or dopant source coating. Among them, when a diffusion process is adopted and the material of the first doped semiconductor portion includes silicon, after the first doped semiconductor portion is formed, a doped silicon glass layer is further formed on the side of the first doped semiconductor portion facing away from the semiconductor substrate. In this case, subsequently, by patterning the doped silicon glass layer, the portion of the doped silicon glass layer remaining on the first region and the overlapping region forms an insulating mask layer; alternatively, after removing the doped silicon glass layer, an insulating mask layer may be formed on the portions of the first doped semiconductor portion corresponding to the first region and the overlapping region by deposition and laser etching processes (the material of the insulating mask layer may be set according to actual requirements and is not specifically limited here. For example: the material of the insulating mask layer may include silicon nitride to perform hydrogen passivation treatment on the side of the first doped semiconductor portion facing away from the semiconductor substrate). After the first doped semiconductor portion disposed entirely is formed and the above-mentioned doped silicon glass layer is not formed, an insulating mask layer may be directly formed on the portions of the first doped semiconductor portion corresponding to the first region and the overlapping region by deposition and laser etching processes.

[0210] Next, under the protection of the insulating mask layer, processes such as wet etching may be used to remove the portions of the first doped semiconductor portion corresponding to the second region. Then, the insulating mask layer is removed to ensure that in the manufactured back-contact battery, the first doped semiconductor portion and the second doped semiconductor portion can be electrically connected within the reverse leakage region.

[0211] Alternatively, the above-mentioned step of forming the first doped semiconductor portion disposed in the first region and the overlapping region may also include: forming a first doped semiconductor portion disposed entirely on or within the first surface; and using a laser etching process to selectively remove the portion of the first doped semiconductor portion corresponding to the second region. The formation method of the first doped semiconductor portion disposed entirely may refer to the foregoing content. After forming the first doped semiconductor portion, under the masking action of a corresponding mask, the portion of the first doped semiconductor portion corresponding to the second region can be directly selectively removed by a laser etching process, so as to save the deposition process and removal process of the mask layer, reduce the manufacturing cost of the back contact battery, and improve the manufacturing efficiency of the back contact battery at the same time.

[0212] It should be noted that when the first doped semiconductor portion is disposed on the first region and the overlapping region, and the back contact battery further includes a first interface passivation layer, processes such as thermal oxidation or chemical vapor deposition can also be used to first form a first interface passivation material disposed entirely on one side of the first surface. Then, before forming the first doped semiconductor portion disposed entirely, the first interface passivation material can be selectively etched to remove the portion of the first interface passivation material corresponding to the second region to obtain the first interface passivation layer; alternatively, after forming the first doped semiconductor portion disposed entirely, under the masking action of the same insulating mask layer, selective etching of the first doped semiconductor portion and the first interface passivation material can be achieved.

[0213] Exemplarily, in the manufactured back contact battery, when the second surface of the semiconductor substrate and the surface of the second region of the first surface are textured surfaces, as Figure 12 shown, before removing the insulating mask layer 30, under the protection of the insulating mask layer 30, the second region 16 and the second surface can be textured so that the second region 16 and the second surface form textured surfaces. After the texturing treatment, the insulating mask layer is removed.

[0214] Next, as Figure 16 shown, a second doped semiconductor portion 13 is formed on the second region 16 and extends to cover a portion of the side of the first doped semiconductor portion 12 facing away from the semiconductor substrate 11 corresponding to the overlapping region 17. The conductivity type of the second doped semiconductor portion 13 is opposite to that of the first doped semiconductor portion 12.

[0215] Exemplarily, as Figure 14 shown, a deposition process can be used to form a second doped semiconductor portion 13 disposed entirely on the second region 16 and the first doped semiconductor portion 12. Then, as Figure 15 shown, etching processes such as deposition and laser etching are used to form a mask layer on the portions of the second doped semiconductor portion 13 corresponding to the second region 16 and the overlapping region 17. Then, as Figure 16As shown, under the masking effect of the mask layer, processes such as wet etching are used to remove a part of the second doped semiconductor portion 13 corresponding to the first region 15. Next, as Figure 17 shown, remove the mask layer.

[0216] Alternatively, the above-mentioned formation of the second doped semiconductor portion disposed on the second region and extending to cover a part of the side of the first doped semiconductor portion facing away from the semiconductor substrate corresponding to the overlapping region may also include the steps of: forming a second doped semiconductor portion disposed entirely on the first doped semiconductor portion and the second region; and using a laser etching process to selectively remove the part of the second doped semiconductor portion corresponding to the first region. The formation method of the second doped semiconductor portion disposed entirely can refer to the previous text. After forming the second doped semiconductor portion, under the masking effect of the corresponding mask plate, the part of the second doped semiconductor portion corresponding to the first region can be directly selectively removed by a laser etching process, so as to save the deposition process and removal process of the mask layer, reduce the manufacturing cost of the back contact battery, and at the same time improve the manufacturing efficiency of the back contact battery.

[0217] It should be noted that when the manufactured back contact battery further includes a second interface passivation layer, before forming the second doped semiconductor portion, a second interface passivation material disposed on the second region and extending to cover the first doped semiconductor portion can be formed by processes such as chemical vapor deposition. Then, before forming the second doped semiconductor portion disposed entirely, the second interface passivation material can be selectively etched to remove the part of the second interface passivation material corresponding to the first region to obtain the second interface passivation layer; or, after forming the second doped semiconductor portion disposed entirely, under the masking effect of the same mask layer, selective etching of the second doped semiconductor portion and the second interface passivation material can be achieved.

[0218] Next, as Figure 18 and Figure 19 shown, a transparent conductive layer 14 covering the second doped semiconductor portion and the first doped semiconductor portion 12 is formed. An insulating groove 18 is provided in the transparent conductive layer 14 to separate the part of the transparent conductive layer 14 corresponding to the first region 15 from the part of the transparent conductive layer 14 corresponding to the second region 16. Among them, at least a part of the overlapping region 17 is a reverse leakage region. In the reverse leakage region, the part of the transparent conductive layer 14 extending from the second region 16 into the overlapping region 17 is the first transparent conductive portion 19, and the first transparent conductive portion 19 is electrically connected to the first doped semiconductor portion 12 through the second doped semiconductor portion 13. The width of the first transparent conductive portion 19 in the first direction is W1, the width of the overlapping region 17 in the first direction is W2, and the ratio of W1 to W2 is greater than or equal to 10% and less than or equal to 90%.

[0219] Exemplarily, processes such as physical vapor deposition can be employed to form a transparent conductive material disposed as a whole layer on the first doped semiconductor portion and the second doped semiconductor portion. Then, an insulating groove can be formed in the transparent conductive layer under the protection of a corresponding mask plate by using a chemical etching paste, laser etching, or the like. The width of the insulating groove in the first direction, and the ratio of the width W1 of the first transparent conductor in the first direction to the width W2 of the overlapping region in the first direction can be referred to the foregoing text and will not be elaborated here.

[0220] Exemplarily, after forming the transparent conductive layer or while forming the insulating groove in the transparent conductive layer, the manufacturing method of the back contact battery may further include the step of selectively etching at least the first transparent conductive portion so that the first transparent conductive portion is discontinuously distributed along the second direction. The second direction intersects the first direction. The lengths of the continuous and discontinuous portions of the first transparent conductive portion along the second direction, the width of the continuous portion of the first transparent conductive portion along the second direction, and the specific direction of the second direction can be referred to the foregoing text and will not be elaborated here.

[0221] In addition, the operation of selectively etching at least the first transparent conductive portion can be performed while forming the insulating groove in the transparent conductive layer. At this time, the manufacturing of the insulating groove and the execution of the above-mentioned selective etching can be achieved through one mask plate, which is beneficial to improving the manufacturing efficiency of the back contact battery. Of course, the above two operations can also be performed separately. Secondly, when there is a notch at the discontinuous region of the third transparent conductive portion corresponding to the first transparent conductive portion in the manufactured back contact battery, the etching agent of the above-mentioned selective etching operation also etches a certain part of the third transparent conductive portion corresponding to the discontinuous region of the first transparent conductive portion to a certain extent. The width of the etching along the first direction can be referred to the foregoing text and will not be elaborated here.

[0222] As Figure 20 shown, then, processes such as screen printing can be used to form a first electrode 25 on the portion of the transparent conductive layer 14 corresponding to the second region 16, and a second electrode 29 on the portion of the transparent conductive layer 14 corresponding to the first region 15.

[0223] For the beneficial effects of the third 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.

[0224] While the above description does not provide detailed technical details regarding patterning and etching of each layer, those skilled in the art will appreciate that various technical means can be employed to form layers, regions, and the like in desired shapes. Furthermore, those skilled in the art may devise methods that differ from those described above to form the same structure. Furthermore, while each embodiment has been described separately, this does not mean that the measures in each embodiment cannot be advantageously combined.

[0225] The above describes the embodiments of the present disclosure. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present disclosure. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art may make various substitutions and modifications, which are intended to fall within the scope of the present disclosure.

Claims

1. A back-contact battery, characterized in that, Comprising: A semiconductor substrate, a first doped semiconductor portion, a second doped semiconductor portion, and a transparent conductive layer; the second doped semiconductor portion and the first doped semiconductor portion have opposite conductivity types; The semiconductor substrate includes opposite first and second surfaces; the first surface includes a first region, a second region, and an overlapping region located between the first region and the second region; the first region, the overlapping region, and the second region are arranged in a first direction; The first doped semiconductor portion is disposed in the first region and the overlapping region; The second doped semiconductor portion is disposed on the second region and extends to cover the first doped semiconductor portion in the overlapping region; The transparent conductive layer covers the second doped semiconductor portion and the first doped semiconductor portion; An insulating groove is provided in the transparent conductive layer to physically insulate the portion of the transparent conductive layer corresponding to the first region from the portion of the transparent conductive layer corresponding to the second region; Wherein, At least a portion of the overlapping region is a reverse leakage region; In the reverse leakage region, the portion of the transparent conductive layer extending from the second region into the overlapping region is a first transparent conductive portion, and the first transparent conductive portion is electrically connected to the first doped semiconductor portion through the second doped semiconductor portion; The width of the first transparent conductive portion in the first direction is W1, the width of the overlapping region in the first direction is W2, and the ratio of W1 to W2 is greater than or equal to 10% and less than or equal to 90%; The reverse leakage region is continuously distributed in a second direction, and the second direction intersects the first direction; or, the reverse leakage region is intermittently distributed in the second direction, and the second direction intersects the first direction. Along the second direction, the first transparent conductive portion has a continuous region and a discontinuous region.

2. The back-contact battery according to claim 1, wherein, The portion of the transparent conductive layer extending from the first region into the overlapping region is a second transparent conductive portion; the width of the second transparent conductive portion in the first direction is W3, and the ratio of W3 to W2 is less than or equal to 80%.

3. The back-contact battery according to claim 1, characterized in that The ratio of W1 to W2 is greater than or equal to 10% and less than or equal to 70%.

4. The back-contact battery according to claim 1, wherein, Along the second direction, the ratio of the length of the discontinuous region to the length of the continuous region is less than or equal to 90%; and / or, The ratio of W1 and W2 is greater than or equal to 20% and less than or equal to 90%; and / or, The ratio of the width of the continuous region to the length of the continuous region is greater than or equal to 1:500 and less than or equal to 5:

1.

5. The back-contact battery according to claim 1, characterized in that, The portion of the transparent conductive layer disposed on the second region is a third transparent conductive portion; a notch is provided in the portion of the third transparent conductive portion corresponding to the discontinuous region.

6. The back-contact battery according to claim 5, characterized in that, The width of the notch in the first direction is less than or equal to 100 μm.

7. The back contact battery according to claim 1, characterized in that, The doping concentration of dopants in the first doped semiconductor portion and / or the second doped semiconductor portion is greater than or equal to 1E19 cm -3 and less than or equal to 5E20 cm -3 ; and / or, The thickness of the first doped semiconductor portion is greater than or equal to 50 nm and less than or equal to 200 nm; and / or, The crystallization rate of the second doped semiconductor portion is less than or equal to 60%; and / or, The thickness of the second doped semiconductor portion is greater than or equal to 5 nm and less than or equal to 50 nm; and / or, The conductivity of the second doped semiconductor portion is greater than or equal to 10E-5 S / cm and less than or equal to 1 S / cm.

8. The back-contact battery according to claim 1, characterized in that, The semiconductor substrate is a silicon substrate; and / or, When the first doped semiconductor portion is formed on the first region and the overlapping region, the back contact battery further includes a first interface passivation layer located between the first doped semiconductor portion and the semiconductor substrate; and / or, The back contact battery further includes a second interface passivation layer, which is located between the second region on the first surface and the second doped semiconductor portion and extends between the second doped semiconductor portion and the first doped semiconductor portion.

9. The back-contact battery according to claim 8, characterized in that, The thickness of the second interface passivation layer is greater than or equal to 2 nm and less than or equal to 20 nm; or, When the doping concentration of the dopant in the first doped semiconductor portion is greater than or equal to 1E19 cm -3 and less than or equal to 5E19 cm -3 , the thickness of the second interface passivation layer is greater than or equal to 5 nm and less than or equal to 15 nm; or, When the doping concentration of the dopant in the first doped semiconductor portion is greater than 5E19 cm -3 and less than or equal to 1E20 cm -3 , the thickness of the second interface passivation layer is greater than or equal to 6 nm and less than or equal to 17 nm; or, When the doping concentration of the dopant in the first doped semiconductor portion is greater than 1E20 cm -3 and less than or equal to 5E20 cm -3 , the thickness of the second interface passivation layer is greater than or equal to 7 nm and less than or equal to 20 nm.

10. The back contact battery according to claim 8, characterized in that, When the back contact battery includes the first interface passivation layer and the second interface passivation layer, the first interface passivation layer and the first doped semiconductor portion constitute a first passivated contact structure, and the second interface passivation layer and the second doped semiconductor portion constitute a second passivated contact structure; wherein, The passivated contact types of the first passivated contact structure and the second passivated contact structure are different; and / or, the thermal stability of the first passivated contact structure is greater than that of the second passivated contact structure; and / or, the first passivated contact structure is a tunneling passivated contact structure; and / or, the second passivated contact structure is a heterojunction contact structure.

11. The back-contact battery according to any one of claims 1 to 8, characterized in that, The back contact battery further includes a surface passivation layer disposed on one side of the second surface included in the semiconductor substrate; the surface passivation layer includes an intrinsic semiconductor passivation layer and a silicon nitride passivation layer that are sequentially stacked along the thickness direction of the semiconductor substrate on one side of the second surface; the material of the intrinsic semiconductor passivation layer includes at least one of amorphous silicon, microcrystalline silicon, and nanocrystalline silicon.

12. The back-contact battery according to any one of claims 1 to 10, characterized in that, The cross-sectional area of the insulating groove gradually decreases in the direction close to the semiconductor substrate; and / or, In the transparent conductive layer, the thicknesses of the regions in the first direction of the portions whose orthographic projections on the first surface do not overlap with the orthographic projection of the insulating groove on the first surface are the same.

13. The back-contact battery according to claim 1, characterized in that, The degree of crystallization of at least a part of the second doped semiconductor portion located in the second region is greater than the degree of crystallization of the part of the second doped semiconductor portion corresponding to the first transparent conductive portion.

14. The back-contact battery according to claim 1, characterized in that, The degree of crystallization of at least a part of the second doped semiconductor portion located in the second region is greater than the degree of crystallization of the part of the second doped semiconductor portion located in the overlapping region.

15. The back-contact battery according to claim 1, 13 or 14, characterized in that, The degree of crystallization of at least a part of the second doped semiconductor portion located in the second region is greater than the degree of crystallization of the part of the second doped semiconductor portion covering the sidewall; The sidewall is located at the junction of the overlapping region and the second region.

16. The back contact battery according to claim 1, characterized in that, The second doped semiconductor portion is divided into a high-crystallization region and a low-crystallization region; the degree of crystallization of the part of the second doped semiconductor portion located in the low-crystallization region is less than the degree of crystallization of the part of the second doped semiconductor portion located in the high-crystallization region; In the second doped semiconductor portion, at least the portion corresponding to the first transparent conductive portion is located in the low crystallization region, and at least a part corresponding to the second region is located in the high crystallization region.

17. The back contact battery according to claim 16, characterized in that, The low crystallization region is located within the overlapping region; Or, along the first direction, one side edge of the low crystallization region is located within the overlapping region, and the other side edge extends to the sidewall; the sidewall is located at the junction of the overlapping region and the second region; Or, along the first direction, one side edge of the low crystallization region is located within the overlapping region and the other side edge extends to the second region; Or, the high crystallization region corresponds to the entire second region.

18. A photovoltaic module, characterized in that, Comprises a back contact cell according to any one of claims 1 to 17.

19. A manufacturing method of a back-contact battery, characterized in that, Comprises: Providing a semiconductor substrate; The semiconductor substrate includes opposite first and second surfaces; the first surface includes a first region, a second region, and an overlapping region located between the first region and the second region; the first region, the overlapping region, and the second region are arranged along a first direction; Forming a first doped semiconductor portion disposed in the first region and the overlapping region; Forming a second doped semiconductor portion disposed on the second region and extending to cover a portion of the side of the first doped semiconductor portion facing away from the semiconductor substrate corresponding to the overlapping region; the second doped semiconductor portion and the first doped semiconductor portion have opposite conductivity types; Forming a transparent conductive layer covering the second doped semiconductor portion and the first doped semiconductor portion; An insulating groove is provided in the transparent conductive layer to separate the portion of the transparent conductive layer corresponding to the first region from the portion of the transparent conductive layer corresponding to the second region; wherein, at least a part of the overlapping region is a reverse leakage region; In the reverse leakage region, the portion of the transparent conductive layer extending from the second region into the overlapping region is a first transparent conductive portion, and the first transparent conductive portion is electrically connected to the first doped semiconductor portion through the second doped semiconductor portion; the width of the first transparent conductive portion in the first direction is W1, the width of the overlapping region in the first direction is W2, and the ratio of W1 to W2 is greater than or equal to 10% and less than or equal to 90%; The reverse leakage region is continuously distributed along a second direction, and the second direction intersects the first direction; or, the reverse leakage region is discontinuously distributed along the second direction, and the second direction intersects the first direction, and along the second direction, the first transparent conductive portion has a continuous region and a discontinuous region.

20. The manufacturing method of the back contact battery according to claim 19, characterized in that, The forming of the first doped semiconductor portion disposed in the first region and the overlapping region includes: Forming a first doped semiconductor portion formed as a whole layer on or within the first surface; Forming an insulating mask layer on the portion of the first doped semiconductor portion corresponding to the first region and the overlapping region; Under the protection of the insulating mask layer, removing the portion of the first doped semiconductor portion corresponding to the second region; Removing the insulating mask layer.

21. The manufacturing method of the back-contact battery according to claim 19, characterized in that, The formation of the first doped semiconductor portion disposed in the first region and the overlapping region includes: forming a first doped semiconductor portion formed as a whole layer on or within the first surface; and using a laser etching process to selectively remove a portion of the first doped semiconductor portion corresponding to the second region; and / or, The formation of the second doped semiconductor portion disposed on the second region and extending to cover a portion of the side of the first doped semiconductor portion facing away from the semiconductor substrate corresponding to the overlapping region includes: forming a second doped semiconductor portion formed as a whole layer on the first doped semiconductor portion and the second region; and using a laser etching process to selectively remove a portion of the second doped semiconductor portion corresponding to the first region; and / or, The formation of the transparent conductive layer covering the second doped semiconductor portion and the first doped semiconductor portion includes: forming a transparent conductive layer formed as a whole layer on the first doped semiconductor portion and the second doped semiconductor portion; and using a laser etching process to form the insulating groove in the transparent conductive layer.

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