A back contact cell and photovoltaic module

Abstract

The application discloses a back contact cell and a photovoltaic module, and relates to the technical field of back contact cells, and aims to solve the problem that the back hook part is not printed well due to the complex back hook structure, thereby affecting the quality of the back contact cell. The back contact cell comprises a first doped semiconductor layer, a second doped semiconductor layer and a lapping part. The first doped semiconductor layer comprises a first part extending along a second direction and adjacent to a rim of the back contact cell, a second part located on a side of the first part away from the rim, a spacing area between the first part and the second part, and a third part located in the spacing area. The second doped semiconductor layer comprises a fourth part extending along a first direction and spaced apart along the second direction. In the spacing area, the third part and the fourth part are alternately and spaced apart arranged along the second direction. The lapping part is connected to the fourth parts located inside and outside the spacing area. In the second direction, the shortest distance between the fourth part located in the spacing area and another fourth part adjacent to the fourth part is greater than the distance between two adjacent fourth parts located outside the spacing area.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of back contact cells, and particularly relates to a back contact cell and a photovoltaic module. BACKGROUND

[0002] The back contact cell is a device for converting solar energy into electricity through photoelectric effect or photochemical effect.

[0003] The back contact cell generally comprises a semiconductor substrate, an edge main grid and an edge pad adjacent to the edge main grid. The edge main grid and the edge pad have a spacing region therebetween. In order to improve the utilization of the spacing region, a plurality of hook-shaped current collecting electrodes are usually arranged in the spacing region.

[0004] However, due to the complex structure of the hook, especially the longitudinally distributed structure, the hook part may be printed poorly, thereby affecting the quality of the back contact cell. SUMMARY

[0005] The present application aims to provide a back contact cell for reducing the number of hook-shaped structures arranged in the spacing region, so as to improve the quality of the back contact cell.

[0006] In order to achieve the above-mentioned purpose, in a first aspect, the present application provides a back contact cell. The back contact cell comprises: a semiconductor substrate comprising opposite first and second surfaces, a first doped semiconductor layer and a second doped semiconductor layer arranged on the first surface of the semiconductor substrate, and the conductive types of the first and second doped semiconductor layers are opposite. In a first direction, the back contact cell comprises two opposite edges. The first doped semiconductor layer comprises: a first part, a second part and a third part. The first part extends in a second direction and is adjacent to the edge, and the first direction is different from the second direction. The second part is located on a side of the first part away from the edge, and the first part and the second part have a spacing region therebetween. The third part is located in the spacing region and extends in the first direction. The third part comprises a connecting part connecting the first part and the second part, and a discontinuous part having a break in the first direction. The second doped semiconductor layer comprises: a fourth part and an overlapping part. A plurality of fourth parts extend in the first direction and are spaced apart in the second direction. In the spacing region, the third part and the fourth part are alternately and spaced apart in the second direction. The overlapping part connects the fourth part located in the spacing region with the fourth part located outside the spacing region; in the second direction, the shortest distance between the fourth part located in the spacing region and another fourth part adjacent to it in the second direction is greater than the distance between the two adjacent fourth parts located outside the spacing region.

[0007] The third part belongs to the first doped semiconductor layer, the fourth part belongs to the second doped semiconductor layer, and the conductive types of the first doped semiconductor layer and the second doped semiconductor layer are opposite. Therefore, the conductive types of the third part and the fourth part are opposite. Further, in the interval region, the third part and the fourth part with opposite conductive types are alternately arranged in the second direction, and the lap joint part connects the fourth part in the interval region and the fourth part outside the interval region. In combination with the actual structure of the back contact battery, the third part is used to form the first polarity electrode, and the fourth part is used to form the second polarity electrode. Therefore, in actual use, the photo-generated current can quickly spread to the opposite collection region to form effective collection, thereby improving the short-circuit current, reducing the series resistance, and further improving the battery performance of the back contact battery. In addition, in the second direction, the shortest distance between the fourth part in the interval region and another fourth part adjacent to it in the second direction is greater than the distance between two adjacent fourth parts outside the interval region. In the interval region, the third part and the fourth part with opposite conductive types are alternately arranged in the second direction. Therefore, under the condition that the area of the interval region is constant, the number of fourth parts in the interval region is reduced. At this time, not only the number of back-hook type second doped semiconductor layers and back-hook type second polarity electrodes arranged in the interval region is reduced, but also the processing difficulty caused by the back-hook structure which is not easy to print is reduced, and the printing efficiency is improved. At the same time, the probability of printing defects caused by the complex back-hook structure is also reduced, and the printing quality is improved, thereby improving the quality of the back contact battery. In addition, due to the reduction of the back-hook structure, the printing of the "longitudinal distribution structure" is reduced, and the probability of printing defects is further reduced, and the printing quality is improved.

[0008] In an implementation manner, along the second direction, the non-continuous part is located on both sides of the connection part. Along the first direction, the disconnection part is located between the non-continuous part and the first part.

[0009] In an implementation manner, along the second direction, the width of the fourth part in the interval region is greater than or equal to 150 μm and less than or equal to 500 μm.

[0010] In the case of the above technical solution, compared with the shortest distance between a fourth part located in the interval region and another fourth part adjacent to it in the second direction, the shortest distance between two fourth parts adjacent to each other outside the interval region is equal; and / or in the case that the third part and the fourth part with opposite conductive types are not alternately arranged in the second direction in the interval region, the number of the third part and / or the fourth part in the interval region is reduced in the present application, so that when the width of the fourth part located in the interval region is within the above range, the reduction of the area of the second doped semiconductor layer caused by the reduction of the number of the fourth part located in the interval region can be compensated for, so as to enhance the electrical conductivity, light absorption and charge separation of the second doped semiconductor layer, thereby improving the cell efficiency of the back contact cell. Further, in the actually manufactured back contact cell, the electrode is formed on the fourth part located in the interval region. Therefore, when the width of the fourth part located in the interval region is within the above range, the width of the electrode formed on the fourth part located in the interval region in the second direction is also within the above range. At this time, it is beneficial to improve the current collection capability of the electrode formed on the fourth part located in the interval region to the current generated in the corresponding region of the semiconductor substrate, realize more efficient transmission of the current, and reduce the loss of the current.

[0011] In an implementation manner, the width of the connecting part is greater than or equal to 150 μm and less than or equal to 500 μm in the second direction.

[0012] In the case of the above technical solution, compared with the shortest distance between a fourth part located in the interval region and another fourth part adjacent to it in the second direction, the shortest distance between two fourth parts adjacent to each other outside the interval region is equal; and / or in the case that the third part and the fourth part with opposite conductive types are not alternately arranged in the second direction in the interval region, the number of the third part and / or the fourth part in the interval region is reduced in the present application, so that when the width of the fourth part located in the interval region is within the above range, the reduction of the area of the second doped semiconductor layer caused by the reduction of the number of the fourth part located in the interval region can be compensated for, so as to enhance the electrical conductivity, light absorption and charge separation of the second doped semiconductor layer, thereby improving the cell efficiency of the back contact cell. Further, in the actually manufactured back contact cell, the electrode is formed on the fourth part located in the interval region. Therefore, when the width of the fourth part located in the interval region is within the above range, the width of the electrode formed on the fourth part located in the interval region in the second direction is also within the above range. At this time, it is beneficial to improve the current collection capability of the electrode formed on the fourth part located in the interval region to the current generated in the corresponding region of the semiconductor substrate, realize more efficient transmission of the current, and reduce the loss of the current.

[0013] In an implementation manner, the length of the second part is greater than or equal to 1 mm and less than or equal to 5 mm in the second direction.

[0014] In the actual back contact cell, the length of the second part is in the above range, and the length of the formed pad is also in the above range. Compared with the case where the length of the pad is less than 1 mm, the connection strength between the pad and the interconnection (for example, the solder strip) in the photovoltaic module can be improved, the welding tension can be ensured, and the connection between the interconnection and the back contact cell can be improved, so as to ensure the yield of the photovoltaic module.

[0015] In an implementation manner, the minimum distance between the second part and the first part is greater than or equal to 1 mm and less than or equal to 5 mm along the first direction.

[0016] In the actual back contact cell, the length of the second part is in the above range, and the length of the formed pad is also in the above range. Compared with the case where the length of the pad is less than 1 mm, the connection strength between the pad and the interconnection (for example, the solder strip) in the photovoltaic module can be improved, the welding tension can be ensured, and the connection between the interconnection and the back contact cell can be improved, so as to ensure the yield of the photovoltaic module.

[0017] In an implementation manner, the number of electrodes arranged in the connection part is greater than or equal to 1.

[0018] In the above technical solution, the number of electrodes arranged in the connection part can be set according to actual conditions, which increases the selectivity, so that the back contact cell can adapt to different application scenarios and expand its application range. Further, when the number of electrodes arranged in the connection part is greater than 1, the current transmission channel is increased, and the current transmission efficiency is improved.

[0019] In an implementation manner, the first doped semiconductor layer further includes: a fifth part extending along the first direction, the fifth part being connected to the side of the second part away from the first part. The sum of the number of the third parts intersecting the side of the second part adjacent to the first part is less than the sum of the number of the fifth parts intersecting the side of the second part away from the first part.

[0020] In an implementation, the fourth portion in the interval region has a width greater than that of the fourth portion outside the interval region in the second direction.

[0021] In the above technical solution, compared with the case where the shortest distance between the fourth portion in the interval region and another fourth portion adjacent to it in the second direction is equal to the distance between two adjacent fourth portions outside the interval region, and / or the case where the third portion and the fourth portion with opposite conductivity type do not alternate in the second direction in the interval region, the number of the third portion and / or the fourth portion in the interval region is reduced in the present application, so that when the width of the fourth portion in the interval region is greater than that of the fourth portion outside the interval region, the reduction of the area of the second doped semiconductor layer caused by the reduction of the number of the fourth portion in the interval region can be compensated for, so as to enhance the conductivity, light absorption and charge separation of the second doped semiconductor layer, thereby improving the cell efficiency of the back contact cell. Further, in the actually manufactured back contact cell, the fourth portion in the interval region is used to form an electrode. Therefore, when the width of the fourth portion in the interval region is greater than that of the fourth portion outside the interval region, the width of the electrode formed on the fourth portion in the interval region in the second direction is also greater than that of the electrode formed on the fourth portion outside the interval region. At this time, it is beneficial to improve the current collection capability of the electrode formed on the fourth portion in the interval region to the current generated in the interval region, to realize more efficient transmission of the current and reduce the loss of the current.

[0022] In a second aspect, the present application further provides a photovoltaic module. The photovoltaic module comprises a cell string and a packaging layer, the cell string is connected by a plurality of back contact cells according to the above technical solution, and the packaging layer is used to cover the surface of the cell string.

[0023] The photovoltaic module provided by the present application has the same beneficial effects as the back contact cell according to the above technical solution, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0024] The accompanying drawings, which are included to provide a further understanding of the present application, form a part of the present application and illustrate the illustrative embodiments of the present application and its description, which do not constitute improper limitations on the present application. In the drawings:

[0025] Figure 1 FIG. 1 is a schematic diagram of the distribution of the first doped semiconductor layer and the second doped semiconductor layer in the back contact cell according to the embodiment of the present application;

[0026] Figure 2 FIG. 2 is a schematic diagram of the partial structure of the back contact cell according to the embodiment of the present application; Figure 1 ​

[0027] Figure 3 Part structure diagram of back contact cell in embodiments of the present application Figure 2 .

[0028] Reference signs:

[0029] 1-first doped semiconductor layer, 10-first part, 11-second part, 12-third part, 120-connection part, 121-non-continuous part, 13-fifth part; 2-second doped semiconductor layer, 20-fourth part, 21-lap joint part; 3-spacing region, 4-first polarity busbar, 5-solder pad, 6-first polarity current collecting electrode, 7-second polarity current collecting electrode. DETAILED DESCRIPTION

[0030] In order to make the technical problems to be solved by the present application, technical solutions and beneficial effects clearer, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not used to limit the present application.

[0031] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0032] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more than two, unless otherwise explicitly and specifically limited. The meaning of "several" is one or more than one, unless otherwise explicitly and specifically limited.

[0033] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0034] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "linking" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium, it can be internal communication of two elements or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0035] The electrode structure of the back contact cell is all on the back of the cell, and the front surface is not blocked by the electrode, so the back contact cell has higher short-circuit current and photoelectric conversion efficiency. The back contact cell generally includes a semiconductor substrate, an edge main grid and an edge pad adjacent to the edge main grid. There is a spacing area between the edge main grid and the edge pad, in order to improve the utilization of the spacing area, a plurality of hook-shaped current collecting electrodes are usually arranged in the spacing area. However, due to the complex structure of the hook, especially the longitudinally distributed structure, the printing of the hook part is not good, which affects the quality of the back contact cell.

[0036] In order to solve the above technical problems, in a first aspect, the embodiments of the present application provide a back contact cell. Referring to Figure 1The back contact cell includes: a semiconductor substrate including opposite first and second faces, a first doped semiconductor layer 1 and a second doped semiconductor layer 2 disposed on the first face of the semiconductor substrate, the first and second doped semiconductor layers 1 and 2 having opposite conductivity types. In a first direction A, the back contact cell includes opposite two edges. The first doped semiconductor layer 1 includes: a first portion 10, a second portion 11 and a third portion 12. The first portion 10 extends in a second direction B and is adjacent to the edge, the first direction A being different from the second direction B. The second portion 11 is located on a side of the first portion 10 away from the edge, and there is a spacing region 3 between the first portion 10 and the second portion 11. The third portion 12 is located in the spacing region 3, and the third portion 12 extends in the first direction A. The third portion 12 includes a connecting portion 120 connecting the first portion 10 and the second portion 11, and a discontinuous portion 121 having a break in the first direction A. The second doped semiconductor layer 2 includes: a fourth portion 20 and a lap portion 21. A plurality of fourth portions 20 extend in the first direction A and are spaced apart in the second direction B. In the spacing region 3, the third portion 12 and the fourth portion 20 are alternately and spaced apart in the second direction B. The lap portion 21 connects the fourth portion 20 located in the spacing region 3 and the fourth portion 20 located outside the spacing region 3. In the second direction B, the shortest distance L1 between the fourth portion 20 located in the spacing region 3 and another fourth portion 20 adjacent to it in the second direction B is greater than the distance L2 between two adjacent fourth portions 20 located outside the spacing region 3. It should be noted that the another fourth portion 20 adjacent to the fourth portion 20 located in the spacing region 3 in the second direction B can be located in the spacing region 3 or not.

[0037] The "shortest distance L1" is explained below, and it should be understood that the following description is for understanding only and is not used for specific definition. Referring to Figure 1 In the spacing region 3, a plurality of fourth portions 20 are included, and each fourth portion 20 has a distance between adjacent fourth portions 20 in the second direction, and the distance includes the distance between the outermost fourth portion 20 in the second direction in the spacing region 3 and the fourth portion 20 adjacent to it which is not located in the spacing region 3. Among all the distances, the shortest distance L1 is the smallest distance.

[0038] Referring to Figure 1 and Figure 2In the back contact cell, the third part 12 belongs to the first doped semiconductor layer 1, the fourth part 20 belongs to the second doped semiconductor layer 2, and the conductive types of the first doped semiconductor layer 1 and the second doped semiconductor layer 2 are opposite. Therefore, the conductive types of the third part 12 and the fourth part 20 are opposite. Further, in the interval area 3, the third part 12 and the fourth part 20 with opposite conductive types are alternately arranged in the second direction B, and the lap part 21 connects the fourth part 20 in the interval area 3 and the fourth part 20 outside the interval area 3. In combination with the actual structure of the back contact cell, the third part 12 is used to form the first polarity electrode, and the fourth part 20 is used to form the second polarity electrode. Therefore, in actual use, the photo-generated current can be quickly diffused to the opposite collection area to form effective collection, thereby improving the short-circuit current, reducing the series resistance, and further improving the cell performance of the back contact cell. In particular, the effective collection of the photo-generated current in the area close to the edge of the back contact cell is realized, and the photoelectric conversion efficiency of the back contact cell is improved. In addition, in the second direction B, the shortest distance between the fourth part 20 in the interval area 3 and another fourth part 20 adjacent to it in the second direction B is greater than the distance between two adjacent fourth parts 20 outside the interval area 3. Further, in the interval area 3, the third part 12 and the fourth part 20 with opposite conductive types are alternately arranged in the second direction B. Therefore, under the condition that the area of the interval area 3 is constant, the number of the fourth part 20 in the interval area 3 is reduced. At this time, not only the number of the hook-shaped second doped semiconductor layer 2 and the hook-shaped second polarity electrode arranged in the interval area 3 is reduced, but also the processing difficulty caused by the hook-shaped structure which is not easy to print is reduced, and the printing efficiency is improved. At the same time, the probability of printing failure caused by the complex hook-shaped structure is also reduced, and the printing quality is improved, thereby improving the quality of the back contact cell. In addition, due to the reduction of the hook-shaped structure, the printing of the "longitudinal distribution structure" is reduced, the probability of printing failure is further reduced, and the printing quality is improved.

[0039] In actual application, the material of the semiconductor substrate is not limited in the embodiments. For example, the semiconductor substrate can be a substrate of any one of a silicon substrate, a germanium-silicon substrate, a germanium substrate, or a gallium arsenide substrate.

[0040] In some embodiments, the semiconductor substrate can be an N-type semiconductor substrate or a P-type semiconductor substrate. The N-type semiconductor substrate is doped with an N-type doping element, which can be any one of a group V element such as a phosphorus (P) element, a bismuth (Bi) element, an antimony (Sb) element, or an arsenic (As) element. The P-type semiconductor substrate is doped with a P-type element, which can be any one of a group III element such as a boron (B) element, an aluminum (Al) element, a gallium (Ga) element, or an indium (In) element.

[0041] For the first doped semiconductor layer and the second doped semiconductor layer, the doping type of the first doped semiconductor layer can be N type, and the doping type of the second doped semiconductor layer can be P type; or the doping type of the first doped semiconductor layer can be P type, and the doping type of the second doped semiconductor layer can be N type. The embodiments of the present application do not make specific limitation on the doping types of the first doped semiconductor layer and the second doped semiconductor layer, as long as the doping types of the two are opposite. When the doping type is P type, the doping type is generally doped with a group III element. When the doping type is N type, the doping type is generally doped with a group V element or a group VI element. In terms of material, the material of the first doped semiconductor layer and / or the second doped semiconductor layer can include any one of semiconductor materials such as silicon, silicon germanium, or germanium. In terms of the arrangement form of the material, the crystal phase of the first doped semiconductor layer and / or the second doped semiconductor layer can be amorphous, microcrystalline, nanocrystalline, single crystal, or polycrystalline.

[0042] When the first surface of the semiconductor substrate includes the first region, the second region, and the isolation region between the first region and the second region, the first doped semiconductor layer is arranged on the first region, the second doped semiconductor layer is arranged on the second region, and the isolation region is used to isolate the first doped semiconductor layer and the second doped semiconductor layer. Referring to Figure 1 The width W1 of the above-mentioned isolation region is greater than or equal to 60 μm and less than or equal to 180 μm. For example, the width of the isolation region can be 60 μm, 80 μm, 100 μm, 120 μm, 150 μm, 165 μm, or 180 μm, etc.

[0043] The above-mentioned first direction and the second direction can be two directions parallel to the surface of the back contact cell and different from each other. Preferably, referring to Figure 1 The above-mentioned first direction A and the second direction B are orthogonal.

[0044] The cross-sectional shape of the above-mentioned overlapping portion parallel to the surface of the semiconductor substrate can be set according to actual conditions, such as a rectangular shape, a polyline shape, etc.

[0045] In the embodiments of the present application, referring to Figure 1 and Figure 2 In the later manufacturing of the back contact cell, the first part 10 is used to form the first polarity edge bus electrode 4, the second part 11 is used to form the electrical connection structure (such as the solder pad 5), the third part 12 is used to form the first polarity current collecting electrode 6, and the fourth part 20 and the overlapping portion 21 are both used to form the second polarity current collecting electrode 7.

[0046] As a possible implementation, referring to Figure 1, along the second direction B, the discontinuous portion 121 is located on both sides of the connecting portion 120. Along the first direction A, the discontinuous portion 121 is located between the first portion 10 and the disconnecting portion.

[0047] As a possible implementation, see Figure 1 , along the second direction B, the width W2 of the fourth portion 20 located in the interval region 3 is greater than or equal to 150 μm and less than or equal to 500 μm. Exemplarily, the width W2 of the fourth portion 20 located in the interval region 3 can be 150 μm, 180 μm, 200 μm, 230 μm, 250 μm, 280 μm, 300 μm, 350 μm, 380 μm, 400 μm, 450 μm, 470 μm, 490 μm or 500 μm, etc.

[0048] See Figure 1 and Figure 2 , compared to in the second direction B, the shortest distance between the fourth portion 20 located in the interval region 3 and another fourth portion 20 adjacent to it in the second direction B is equal to the distance between the adjacent two fourth portions 20 located outside the interval region 3; and / or, in the case that the third portion 12 and the fourth portion 20 of opposite conductivity type are not alternately arranged along the second direction B within the interval region 3, the number of the third portion 12 and / or the fourth portion 20 within the interval region 3 is reduced in the present application, thus when the width of the fourth portion 20 located in the interval region 3 is within the above range, the reduction of the area of the second doped semiconductor layer 2 due to the reduction of the number of the fourth portion 20 located in the interval region 3 can be compensated, so as to enhance the electrical conductivity, light absorption and charge separation of the second doped semiconductor layer 2, thereby improving the cell efficiency of the back contact cell. Further, in the actually manufactured back contact cell, the electrode is formed on the fourth portion 20 located in the interval region 3. Therefore, when the width of the fourth portion 20 located in the interval region 3 is within the above range, the width of the electrode formed on the fourth portion 20 located in the interval region 3 in the second direction B is also within the above range. At this time, it is beneficial to improve the current collecting capability of the electrode formed on the fourth portion 20 located in the interval region 3 to the current generated in the corresponding region of the semiconductor substrate, to realize more efficient transmission of the current and reduce the loss of the current.

[0049] Further, see Figure 1 , along the second direction B, the width W2 of the fourth portion 20 located in the interval region 3 is greater than the width W3 of the fourth portion 20 located outside the interval region 3.

[0050] See Figure 1 and Figure 2, compared to in the second direction B, the shortest distance between the fourth portion 20 located in the interval region 3 and another fourth portion 20 adjacent to it in the second direction B is equal to the distance between two adjacent fourth portions 20 located outside the interval region 3; and / or, in the case where the third portions 12 and the fourth portions 20 of opposite conductivity types are not alternately arranged in the second direction B within the interval region 3, the number of the third portions 12 and / or the fourth portions 20 within the interval region 3 is reduced in the present application, so that when the width of the fourth portion 20 located in the interval region 3 is greater than the width of the fourth portion 20 located outside the interval region 3, the reduction of the area of the second doped semiconductor layer 2 due to the reduction of the number of the fourth portion 20 located in the interval region 3 can be compensated, so as to enhance the electrical conductivity, light absorption and charge separation of the second doped semiconductor layer 2, thereby improving the cell efficiency of the back contact cell. Further, in the actually manufactured back contact cell, the electrode is formed on the fourth portion 20 located in the interval region 3. Therefore, when the width of the fourth portion 20 located in the interval region 3 is greater than the width of the fourth portion 20 located outside the interval region 3, the width of the electrode formed on the fourth portion 20 located in the interval region 3 in the second direction B is also greater than the width of the electrode formed on the fourth portion 20 located outside the interval region 3 in the second direction B. At this time, it is beneficial to improve the current collection capability of the electrode formed on the fourth portion 20 located in the interval region 3 to the current generated in the interval region 3, realize more efficient transmission of the current, and reduce the loss of the current.

[0051] Referring to Figures 1 to 3 , in combination with the foregoing description, since the number of the fourth portion 20 located in the interval region 3 is reduced, the width of the connecting portion 120 located in the interval region 3 can be increased compared to the case where the number of the fourth portion 20 located in the interval region 3 is not reduced under the condition that the area of the interval region 3 is constant. Further, when the width of the connecting portion 120 is increased, the width of the electrode formed in the connecting portion 120 later and / or the number of the electrode formed in the connecting portion 120 later can be increased. At this time, not only the area of the blank region in the interval region 3 is further reduced, the utilization rate of the interval region 3 is improved, but also the current collection capability of the electrode formed on the connecting portion 120 to the current generated in the corresponding region of the semiconductor substrate is improved, the current is transmitted more efficiently, and the loss of the current is reduced.

[0052] As a possible implementation manner, referring to Figure 1In the second direction B, the width W4 of the connecting portion 120 is greater than or equal to 150 μm and less than or equal to 500 μm. Exemplarily, the width W4 of the connecting portion 120 can be 150 μm, 180 μm, 200 μm, 230 μm, 250 μm, 280 μm, 300 μm, 350 μm, 380 μm, 400 μm, 450 μm, 470 μm, 490 μm or 500 μm, etc.

[0053] Referring to Figure 1 and Figure 2 , compared with the shortest distance between the fourth portion 20 located in the interval region 3 and another fourth portion 20 adjacent to it in the second direction B, the distance between the adjacent two fourth portions 20 located outside the interval region 3 is equal; and / or, in the case that the third portion 12 and the fourth portion 20 of opposite conductivity type are not alternately arranged in the second direction B in the interval region 3, the number of the third portion 12 and / or the fourth portion 20 in the interval region 3 is reduced in the present application, so that when the width of the connecting portion 120 is within the above range, the reduction of the area of the first doped semiconductor layer 1 caused by the reduction of the number of the third portion 12 located in the interval region 3 can be compensated, so as to enhance the conductivity, light absorption and charge separation of the first doped semiconductor layer 1, thereby improving the cell efficiency of the back contact cell. Further, in the actually manufactured back contact cell, the connecting portion 120 is used to form an electrode. Therefore, when the width of the connecting portion 120 is within the above range, the width of the electrode formed on the connecting portion 120 in the second direction B is also within the above range. At this time, it is beneficial to improve the current collecting capacity of the electrode formed on the connecting portion 120 to the current generated in the corresponding region of the semiconductor substrate, to realize more efficient transmission of the current and reduce the loss of the current.

[0054] As a possible implementation, referring to Figure 2 and Figure 3 , the number of the electrodes arranged in the connecting portion 120 is greater than or equal to 1. The number of the electrodes arranged in the connecting portion 120 can be set according to actual conditions, which increases the selectivity, so that the back contact cell can adapt to different application scenarios and expand its application range. Further, when the number of the electrodes arranged in the connecting portion 120 is greater than 1, the transmission channel of the current is increased, and the current transmission efficiency is improved.

[0055] Exemplarily, referring to Figure 2 , one first polarity collecting electrode 6 is arranged on the connecting portion 120. Referring to Figure 3 , two first polarity collecting electrodes 6 are arranged on the connecting portion 120.

[0056] As a possible implementation, referring toFigure 1 The minimum distance L3 between the second portion 11 and the first portion 10 along the first direction A is greater than or equal to 1 mm and less than or equal to 5 mm. Exemplarily, the minimum distance L3 can be 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm or 5 mm, etc.

[0057] Referring to Figure 1 and Figure 2 In the actual back contact cell, the second portion 11 is used to form an electrical connection structure (for example, the solder pad 5), and because the minimum distance L3 between the second portion 11 and the first portion 10 is within the above range, the later-formed solder pad 5 is away from the first portion 10 adjacent to the edge of the back contact cell, so that the solder pad 5 is away from the edge of the back contact cell. At this time, in the process of later manufacturing the photovoltaic module, the interconnector (for example, the solder ribbon) connected with the solder pad 5 can be away from the edge of the back contact cell to avoid the situation of the back contact cell cracking due to the roughness of the edge of the back contact cell itself and the stress concentration caused by the solder ribbon in the connection process, thereby improving the yield and reliability of the photovoltaic module. Further, when the solder pad 5 is away from the edge of the back contact cell, the two sides of the solder pad 5 along the first direction A can be connected with the current collecting electrode, and at this time the solder pad 5 can collect the carriers collected by the current collecting electrodes on both sides. Compared with the case where the solder pad 5 is arranged at the edge of the back contact cell and only one side of the solder pad 5 is connected with the current collecting electrode, the application shortens the transmission distance of the carriers and reduces the current loss.

[0058] As a possible implementation manner, referring to Figure 1 The length L4 of the second portion 11 along the second direction B is greater than or equal to 1 mm and less than or equal to 5 mm. Exemplarily, the length L4 of the second portion 11 can be 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm or 5 mm, etc.

[0059] Referring to Figure 1 and Figure 2 In the actual back contact cell, the second portion 11 is used to form an electrical connection structure (for example, the solder pad 5), and because the length L4 of the second portion 11 is within the above range, the length of the later-formed solder pad 5 is also within the above range. Compared with the case where the length of the solder pad 5 is less than 1 mm, in the process of later manufacturing the photovoltaic module, the connection strength between the solder pad 5 in the application and the interconnector (for example, the solder ribbon) can be improved to ensure the soldering tension, thereby improving the firmness of the connection between the interconnector and the back contact cell to ensure the yield of the photovoltaic module.

[0060] As a possible implementation manner, referring to Figure 1The first doped semiconductor layer 1 further comprises fifth portions 13 extending along the first direction A, the fifth portions 13 being connected to the side of the second portion 11 distal to the first portion 10. The sum of the number of the third portions 12 intersecting the side of the second portion 11 proximal to the first portion 10 is less than the sum of the number of the fifth portions 13 intersecting the side of the second portion 11 distal to the first portion 10.

[0061] For example, referring to Figure 1 The number of the third portions 12 intersecting the side of the second portion 11 proximal to the first portion 10 is three, and the number of the fifth portions 13 intersecting the side of the second portion 11 distal to the first portion 10 is four. Further, the third portions 12 and the fifth portions 13 can both be used to form the first polarity current collecting electrode 6 when the back contact cell is manufactured in a post-production process.

[0062] In a second aspect, an embodiment of the present application further provides a photovoltaic module. The photovoltaic module comprises a cell string and an encapsulation layer, the cell string being connected by a plurality of back contact cells according to the above technical solution, and the encapsulation layer being used to cover the surface of the cell string.

[0063] The photovoltaic module provided by the embodiment of the present application has the same beneficial effects as the back contact cell according to the above technical solution, and thus will not be described here.

[0064] In the description of the above-described embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner. The above description is merely a specific implementation of the present application, and the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A back contact battery, characterized in that: include: A semiconductor substrate comprising a first side and a second side facing each other; a first doped semiconductor layer and a second doped semiconductor layer disposed on the first surface of the semiconductor substrate; The first doped semiconductor layer and the second doped semiconductor layer have opposite conductivity types; Along a first direction, the back contact cell includes two opposite edges; The first doped semiconductor layer comprises: a first portion extending along a second direction and adjacent to the edge; the first direction being different from the second direction; a second portion located on a side of the first portion away from the edge; a spacing area being defined between the first portion and the second portion; a third portion located in the spacing area and extending along the first direction; The third portion includes a connecting portion connecting the first portion and the second portion, and a discontinuous portion having a disconnected portion in the first direction; The second doped semiconductor layer comprises: a fourth portion, wherein a plurality of the fourth portions extend along the first direction and are spaced apart along the second direction; and within the spaced area, the third portion and the fourth portion are alternately spaced apart along the second direction; an overlapping portion connecting the fourth portion located within the spacing area with the fourth portion located outside the spacing area; In the second direction, the shortest distance between the fourth portion located in the spacing area and another fourth portion adjacent thereto in the second direction is greater than the distance between two adjacent fourth portions located outside the spacing area.

2. The back contact battery according to claim 1, characterized in that Along the second direction, the discontinuous portion is located on both sides of the connecting portion; Along the first direction, the disconnection portion is located between the discontinuous portion and the first portion.

3. The back contact battery according to claim 1, characterized in that Along the second direction, a width of the fourth portion located in the spacing region is greater than or equal to 150 μm and less than or equal to 500 μm.

4. The back contact battery according to claim 1, characterized in that Along the second direction, a width of the connecting portion is greater than or equal to 150 μm and less than or equal to 500 μm.

5. The back contact battery according to claim 1, characterized in that Along the second direction, a length of the second portion is greater than or equal to 1 mm and less than or equal to 5 mm.

6. The back contact battery according to claim 1, characterized in that Along the first direction, a minimum distance between the second portion and the first portion is greater than or equal to 1 mm and less than or equal to 5 mm.

7. The back contact battery according to claim 1 or 4, characterized in that The number of electrodes disposed in the connecting portion is greater than or equal to one.

8. The back contact battery according to claim 1, characterized in that The first doped semiconductor layer further includes: a fifth portion extending along the first direction, the fifth portion being connected to a side of the second portion away from the first portion; The sum of the number of the third portions intersecting the side of the second portion adjacent to the first portion is smaller than the sum of the number of the fifth portions intersecting the side of the second portion away from the first portion.

9. The back contact battery according to claim 1 or 3, characterized in that Along the second direction, a width of the fourth portion located within the spacing area is greater than a width of the fourth portion located outside the spacing area.

10. A photovoltaic module, characterized in that: The photovoltaic module comprises: A battery string, the battery string being formed by connecting a plurality of back-contact batteries according to any one of claims 1 to 9; The encapsulation layer is used to cover the surface of the battery string.

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