Back contact battery and photovoltaic module

Abstract

The invention discloses a back contact battery and a photovoltaic module, relates to the technical field of back contact batteries, and aims to solve the problem that the quality of the back contact battery is affected due to poor printing of a back hook part caused by a complex back hook structure. The first doped semiconductor layer comprises a first part which extends along a second direction and is adjacent to the edge of the back contact cell, a second part is positioned on one side, far away from the edge, of the first part, a spacer region is arranged between the first part and the second part, and a third part is positioned in the spacer region. And the second doped semiconductor layer comprises fourth parts which extend along the first direction and are distributed at intervals along the second direction. In the interval area, the third parts and the fourth parts are alternately arranged at intervals in the second direction. The lap joint part is connected with the fourth part inside and outside the interval area; in the second direction, the shortest distance between the fourth part located in the interval area and the other adjacent fourth part is larger than the distance between the two adjacent fourth parts located outside the interval area.

Description

Technical Field

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

[0002] A back-contact cell is a device that utilizes solar energy and directly converts light energy into electrical energy through the photoelectric effect or photochemical effect.

[0003] The above-mentioned back contact battery generally includes a semiconductor substrate, an edge busbar and an edge pad adjacent to the edge busbar. There is a spacing area between the edge busbar and the edge pad. In order to improve the utilization of the spacing area, a plurality of hook-type collector electrodes are usually arranged in the spacing area.

[0004] However, since the hook has a complex structure, especially a longitudinally distributed structure, poor printing of the hook portion may occur, thereby affecting the quality of the back contact battery. Summary of the invention

[0005] An object of the present invention is to provide a back-contact battery, which is used to reduce the number of hook-back structures arranged in the spacing area to improve the quality of the back-contact battery.

[0006] In order to achieve the above-mentioned object, in a first aspect, the present invention provides a back contact battery. The back contact battery comprises: a semiconductor substrate comprises a first surface and a second surface opposite to each other, a first doped semiconductor layer and a second doped semiconductor layer are arranged on the first surface of the semiconductor substrate, and the first doped semiconductor layer and the second doped semiconductor layer have opposite conductivity types. Along the first direction, the back contact battery comprises two opposite edges. The first doped semiconductor layer comprises: a first part, a second part and a third part. The first part extends along the second direction and is adjacent to the edge, and the first direction is different from the second direction. The second part is located on the side of the first part away from the edge, and there is a spacing area between the first part and the second part. The third part is located in the spacing area and extends along the first direction. The third part comprises a connecting part connecting the first part and the second part, and a discontinuous part having a disconnection part in the first direction. The second doped semiconductor layer comprises: a fourth part and an overlapping part. A plurality of fourth parts extend along the first direction and are spaced apart along the second direction. In the spacing area, the third part and the fourth part are alternately spaced along the second direction. The overlapping portion connects 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 within the spacing area and another fourth portion adjacent to it in the second direction is greater than the distance between two adjacent fourth portions located outside the spacing area.

[0007] In the back contact battery provided by the present invention, since the third part belongs to the first doped semiconductor layer, the fourth part belongs to the second doped semiconductor layer, and the first doped semiconductor layer and the second doped semiconductor layer have opposite conductivity types. Therefore, the conductivity types of the third part and the fourth part are opposite. Further, in the spacing area, the third part and the fourth part of opposite conductivity types are alternately arranged in the second direction, and the overlapping part connects the fourth part located in the spacing area with the fourth part located outside the spacing area. Combined 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 the actual use process, the photocurrent can quickly diffuse to the opposite collection area to form an effective collection, thereby increasing the short-circuit current, reducing the series resistance, and thus improving the battery performance of the back contact battery. In addition, in the second direction, the shortest distance between the fourth part located in the spacing area 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 area; and in the spacing area, the third part and the fourth part of opposite conductivity types are alternately arranged in the second direction. Therefore, when the area of ​​the spacing area is constant, the number of fourth parts located in the spacing area is reduced. At this time, not only the number of the hook-back type second doped semiconductor layer and the hook-back type second polarity electrode arranged in the spacing area is reduced, the processing difficulty caused by the difficulty in printing of the hook-back structure is reduced, and the printing efficiency is improved; at the same time, the probability of poor printing due to the complexity of the hook-back structure is reduced, the printing quality is improved, and thus the quality of the back contact battery is improved; in addition, due to the reduction of the hook-back structure, the printing of the "longitudinal distributed structure" is reduced, which further reduces the probability of poor printing and improves the printing quality.

[0008] In one implementation, 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.

[0009] In an implementation manner, 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.

[0010] In the case of adopting the above technical solution, compared with the case where the shortest spacing between the fourth part located in the spacing region and another fourth part adjacent to it in the second direction is equal to the spacing between two adjacent fourth parts located outside the spacing region; and / or, in the spacing region, the third part and the fourth part of opposite conductivity type are not arranged alternately along the second direction, in the present application, the number of the third part and / or the fourth part in the spacing region is reduced, so when the width of the fourth part located in the spacing region is within the above value range, it can make up for the reduction in the area of ​​the second doped semiconductor layer caused by the reduction in the number of the fourth part located in the spacing region, so as to enhance the conductivity, light absorption and charge separation of the second doped semiconductor layer, thereby improving the battery efficiency of the back contact battery. Further, in the actual back contact battery, the fourth part located in the spacing region is used to form an electrode. Therefore, when the width of the fourth part located in the spacing region is within the above value range, the width of the electrode formed on the fourth part located in the spacing region in the second direction is also within the above value range. At this time, it is beneficial to improve the ability of the electrode formed on the fourth part located in the spacing region to collect the current generated in the corresponding region on the semiconductor substrate, realize more efficient transmission of the current, and reduce the loss of the current.

[0011] In an implementation manner, along the second direction, a width of the connection portion is greater than or equal to 150 μm and less than or equal to 500 μm.

[0012] In the case of adopting the above technical solution, compared with the shortest spacing between the fourth part located in the spacing region and another fourth part adjacent to it in the second direction in the second direction, which is equal to the spacing between two adjacent fourth parts located outside the spacing region; and / or, in the spacing region, the third part and the fourth part of opposite conductivity type are not arranged alternately along the second direction, in the present application, the number of the third part and / or the fourth part in the spacing region is reduced, so when the width of the connecting part is within the above value range, it can make up for the reduction in the area of ​​the first doped semiconductor layer caused by the reduction in the number of the third part located in the spacing region, so as to enhance the conductivity, light absorption and charge separation of the first doped semiconductor layer, thereby improving the battery efficiency of the back contact battery. Further, in the actual back contact battery, the connecting part is used to form an electrode. Therefore, when the width of the connecting part is within the above value range, the width of the electrode formed on the connecting part in the second direction is also within the above value range. At this time, it is beneficial to improve the ability of the electrode formed on the connecting part to collect the current generated in the corresponding area on the semiconductor substrate, realize more efficient transmission of the current, and reduce the loss of the current.

[0013] In one implementation, 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.

[0014] When the above technical solution is adopted, in the back contact battery actually manufactured, the second part is used to form an electrical connection structure (such as a pad). Since the length of the second part is within the above value range, the length of the pad formed later is also within the above value range. Compared with the case where the pad length is less than 1 mm, in the process of later manufacturing photovoltaic modules, the connection strength between the pad in this application and the interconnection member (such as a welding strip) can be improved to ensure the welding tension, thereby improving the firmness of the connection between the interconnection member and the back contact battery to ensure the yield rate of the photovoltaic module.

[0015] In an implementation, 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.

[0016] When actually manufacturing a back-contact battery, the second part is used to form an electrical connection structure (such as a pad). Since the minimum distance between the second part and the first part is within the above-mentioned value range, the pad formed later is away from the first part adjacent to the edge of the back-contact battery, so that the pad is away from the edge of the back-contact battery. At this time, in the process of later manufacturing photovoltaic modules, the interconnection member (such as a solder strip) connected to the pad can be kept away from the edge of the back-contact battery to avoid the occurrence of hidden cracks in the back-contact battery caused by factors such as the roughness of the edge of the back-contact battery itself and the stress concentration caused by the solder strip during the connection process, thereby improving the yield rate and reliability of the photovoltaic module. Further, when the pad is away from the edge of the back-contact battery, both sides of the pad along the first direction can be connected to the collector electrode, and the pad can collect the carriers collected by the collector electrodes on both sides thereof. Compared with the situation where the pad is set at the edge of the back-contact battery and only one side of the pad is connected to the collector electrode, the present application shortens the transmission distance of the carrier and reduces the current loss.

[0017] In one implementation, the number of electrodes disposed in the connecting portion is greater than or equal to one.

[0018] When the above technical solution is adopted, the number of electrodes arranged in the connection part can be set according to the actual situation, which increases the selectivity, enables the back contact battery to adapt to different application scenarios, and expands its application range. Furthermore, 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 one implementation, 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 with a side of the second portion adjacent to the first portion is less than the sum of the number of the fifth portions intersecting with a side of the second portion away from the first portion.

[0020] In one implementation, along the second direction, a width of the fourth portion located within the spacing region is greater than a width of the fourth portion located outside the spacing region.

[0021] In the case of adopting the above technical solution, compared with the case where the shortest distance between the fourth part located in the spacing region and another fourth part adjacent to it in the second direction is equal to the distance between two adjacent fourth parts located outside the spacing region; and / or, in the spacing region, the third part and / or the fourth part of opposite conductivity type are not arranged alternately along the second direction, the number of the third part and / or the fourth part in the spacing region is reduced in the present application, so when the width of the fourth part located in the spacing region is greater than the width of the fourth part located outside the spacing region, the reduction in the area of ​​the second doped semiconductor layer caused by the reduction in the number of the fourth part located in the spacing region can be compensated, so as to enhance the conductivity, light absorption and charge separation of the second doped semiconductor layer, thereby improving the battery efficiency of the back contact battery. Further, in the actual back contact battery, the fourth part located in the spacing region is used to form an electrode. Therefore, when the width of the fourth part located in the spacing region is greater than the width of the fourth part located outside the spacing region, the width of the electrode formed on the fourth part located in the spacing region in the second direction is also greater than the width of the electrode formed on the fourth part located outside the spacing region in the second direction. At this time, it is beneficial to improve the ability of the electrode formed on the fourth part located in the spacing area to collect the current generated in the spacing area, realize more efficient transmission of the current, and reduce the loss of the current.

[0022] In a second aspect, the present invention further provides a photovoltaic module, which includes a battery string and an encapsulation layer, wherein the battery string is formed by connecting a plurality of back-contact batteries according to the above technical solution, and the encapsulation layer is used to cover the surface of the battery string.

[0023] The beneficial effects of the photovoltaic module provided by the present invention are the same as the beneficial effects of the back-contact battery described in the above technical solution, and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0025] Figure 1 Schematic diagram of the distribution of the first doped semiconductor layer and the second doped semiconductor layer in the back contact cell according to an embodiment of the present invention;

[0026] Figure 2 Schematic diagram of the partial structure of the back contact battery in an embodiment of the present invention Figure 1 ;

[0027] Figure 3 Schematic diagram of the partial structure of the back contact battery in an embodiment of the present invention Figure 2 .

[0028] Reference numerals:

[0029] 1-first doped semiconductor layer, 10-first part, 11-second part, 12-third part, 120-connecting part, 121-non-continuous part, 13-fifth part; 2-second doped semiconductor layer, 20-fourth part, 21-overlapping part; 3-spacer area, 4-first polarity edge bus electrode, 5-soldering pad, 6-first polarity collecting electrode, 7-second polarity collecting electrode. DETAILED DESCRIPTION

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

[0031] It should be noted that when an element is referred to as being "fixed to" or "disposed 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" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The meaning of "several" is one or more, unless otherwise clearly and specifically defined.

[0033] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by the terms "up", "down", "front", "back", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0034] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] The electrode structure of the back-contact battery is on the back of the battery, and there is no electrode blocking the front. Therefore, the back-contact battery has a higher short-circuit current and photoelectric conversion efficiency. The back-contact battery 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-type collector electrodes are usually arranged in the spacing area. However, since the hook has a complex structure, especially a longitudinally distributed structure, the hook part may be poorly printed, which in turn affects the quality of the back-contact battery.

[0036] In order to solve the above technical problems, in the first aspect, an embodiment of the present invention provides a back contact battery. Figure 1, the back contact battery comprises: a semiconductor substrate comprises a first surface and a second surface opposite to each other, a first doped semiconductor layer 1 and a second doped semiconductor layer 2 arranged on the first surface of the semiconductor substrate, and the first doped semiconductor layer 1 and the second doped semiconductor layer 2 have opposite conductivity types. Along the first direction A, the back contact battery comprises two opposite edges. The first doped semiconductor layer 1 comprises: a first portion 10, a second portion 11 and a third portion 12. The first portion 10 extends along the second direction B and is adjacent to the edge, and the first direction A is 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 along the first direction A. The third portion 12 comprises a connecting portion 120 connecting the first portion 10 and the second portion 11, and a discontinuous portion 121 having a disconnection portion in the first direction A. The second doped semiconductor layer 2 comprises: a fourth portion 20 and an overlapping portion 21. A plurality of fourth portions 20 extend along the first direction A and are spaced apart along the second direction B. In the spacing area 3, the third portion 12 and the fourth portion 20 are alternately arranged along the second direction B. The overlapping portion 21 connects the fourth portion 20 located in the spacing area 3 with the fourth portion 20 located outside the spacing area 3. In the second direction B, the shortest distance L1 between the fourth portion 20 located in the spacing area 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 area 3. It should be noted that another fourth portion 20 adjacent to the fourth portion 20 located in the spacing area 3 in the second direction B may be located in the spacing area 3 or may not be located in the spacing area 3.

[0037] The "shortest distance L1" is explained below. It should be understood that the following description is only for understanding and is not intended to be a specific limitation. Figure 1 , a plurality of fourth portions 20 are included in the spacing region 3, and each fourth portion 20 has a spacing between adjacent fourth portions 20 in the second direction, and the spacing includes the spacing between the outermost fourth portion 20 in the spacing region 3 in the second direction and the adjacent fourth portion 20 not located in the spacing region 3. Among them, the shortest spacing L1 is the shortest spacing among all the above spacings.

[0038] See also Figure 1 and Figure 2In the back contact cell provided by the embodiment of the present invention, since 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 first doped semiconductor layer 1 and the second doped semiconductor layer 2 have opposite conductivity types. Therefore, the third part 12 and the fourth part 20 have opposite conductivity types. Further, in the spacing area 3, the third part 12 and the fourth part 20 of opposite conductivity types are alternately arranged along the second direction B, and the overlapping part 21 connects the fourth part 20 located in the spacing area 3 with the fourth part 20 located outside the spacing area 3. Combined 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 photogenerated current can quickly diffuse to the opposite collection area to form effective collection, thereby increasing the short-circuit current, reducing the series resistance, and thus improving the battery performance of the back contact cell. In particular, the effective collection of the photogenerated current in the area near the edge of the back contact cell is achieved, 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 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 between two adjacent fourth portions 20 located outside the spacing region 3; and in the spacing region 3, the third portion 12 and the fourth portion 20 of opposite conductivity types are alternately arranged along the second direction B. Therefore, when the area of ​​the spacing region 3 is constant, the number of the fourth portions 20 located in the spacing region 3 is reduced. At this time, not only the number of the hook-back second doped semiconductor layer 2 and the hook-back second polarity electrode arranged in the spacing region 3 is reduced, the processing difficulty caused by the difficulty of printing the hook-back structure is reduced, and the printing efficiency is improved; at the same time, the probability of poor printing caused by the complexity of the hook-back structure is reduced, the printing quality is improved, and thus the quality of the back contact battery is improved; in addition, due to the reduction of the hook-back structure, the printing of the "vertical distribution structure" is reduced, the probability of poor printing is further reduced, and the printing quality is improved.

[0039] In actual application, the embodiment of the present invention does not specifically limit the material of the semiconductor substrate. For example, the semiconductor substrate can be a substrate made of any semiconductor material such as a silicon substrate, a silicon germanium substrate, a germanium substrate, or a gallium arsenide substrate.

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

[0041] For the first doped semiconductor layer and the second doped semiconductor layer, in terms of doping type, the doping type of the first doped semiconductor layer may be N-type, and the doping type of the second doped semiconductor layer is P-type; or, the doping type of the first doped semiconductor layer may also be P-type, and the doping type of the second doped semiconductor layer is N-type. The embodiment of the present invention does not specifically limit the doping type 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, it is generally doped with group III elements. When the doping type is N-type, it is generally doped with group V elements or group VI elements. In terms of materials, the material of the first doped semiconductor layer and / or the second doped semiconductor layer may include any semiconductor material such as silicon, germanium silicon or germanium. In terms of the arrangement of the material, the crystal phase of the first doped semiconductor layer and / or the second doped semiconductor layer may be amorphous, microcrystalline, nanocrystalline, single crystal or polycrystalline, etc.

[0042] When the first surface of the semiconductor substrate includes a first region, a second region, and an isolation region between the first region and the second region, the first doped semiconductor layer is disposed on the first region, the second doped semiconductor layer is disposed on the second region, and the isolation region is used to isolate the first doped semiconductor layer from the second doped semiconductor layer. Figure 1 The width W1 of the 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 may be 60 μm, 80 μm, 100 μm, 120 μm, 150 μm, 165 μm or 180 μm.

[0043] The first direction and the second direction may be parallel to the surface of the back contact battery and may be two different directions. Figure 1 , the first direction A and the second direction B are orthogonal.

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

[0045] In the embodiments of the present invention, see Figure 1 and Figure 2 When the back-contact battery is manufactured later, 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 pad 5), the third part 12 is used to form the first polarity collector electrode 6, and the fourth part 20 and the overlapping part 21 are both used to form the second polarity collector electrode 7.

[0046] As a possible implementation, see 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 disconnection portion is located between the discontinuous portion 121 and the first portion 10 .

[0047] As a possible implementation, see Figure 1 , along the second direction B, the width W2 of the fourth portion 20 located in the spacing 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 spacing region 3 may 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 also Figure 1 and Figure 2 , compared to the shortest distance between the fourth portion 20 located in the spacing region 3 and another fourth portion 20 adjacent to it in the second direction B in the second direction B, which is equal to the distance between two adjacent fourth portions 20 located outside the spacing region 3; and / or, in the spacing region 3, the third portion 12 and the fourth portion 20 of opposite conductivity types are not arranged alternately along the second direction B. In the present application, the number of the third portion 12 and / or the fourth portion 20 in the spacing region 3 is reduced, so when the width of the fourth portion 20 located in the spacing region 3 is within the above value range, the reduction in the area of ​​the second doped semiconductor layer 2 caused by the reduction in the number of the fourth portion 20 located in the spacing region 3 can be compensated, so as to enhance the conductivity, light absorption and charge separation of the second doped semiconductor layer 2, thereby improving the battery efficiency of the back contact battery. Further, in the actual back contact battery, the fourth portion 20 located in the spacing region 3 is used to form an electrode. Therefore, when the width of the fourth portion 20 located in the spacing region 3 is within the above value range, the width of the electrode formed on the fourth portion 20 located in the spacing region 3 in the second direction B is also within the above value range. At this time, it is beneficial to improve the ability of the electrode formed on the fourth part 20 located in the spacing area 3 to collect the current generated in the corresponding area on the semiconductor substrate, realize more efficient transmission of the current, and reduce the current loss.

[0049] Further, see Figure 1 , along the second direction B, a width W2 of the fourth portion 20 located within the spacing area 3 is greater than a width W3 of the fourth portion 20 located outside the spacing area 3 .

[0050] See also Figure 1 and Figure 2, compared to the shortest distance between the fourth portion 20 located in the spacing region 3 and another fourth portion 20 adjacent to it in the second direction B in the second direction B, which is equal to the distance between two adjacent fourth portions 20 located outside the spacing region 3; and / or, in the spacing region 3, the third portion 12 and the fourth portion 20 of opposite conductivity types are not arranged alternately along the second direction B. In the present application, the number of the third portion 12 and / or the fourth portion 20 in the spacing region 3 is reduced, so when the width of the fourth portion 20 located in the spacing region 3 is greater than the width of the fourth portion 20 located outside the spacing region 3, the reduction in the area of ​​the second doped semiconductor layer 2 caused by the reduction in the number of the fourth portion 20 located in the spacing region 3 can be compensated, so as to enhance the conductivity, light absorption and charge separation of the second doped semiconductor layer 2, thereby improving the battery efficiency of the back contact battery. Further, in the actual back contact battery, the fourth portion 20 located in the spacing region 3 is used to form an electrode. Therefore, when the width of the fourth portion 20 located in the spacing region 3 is greater than the width of the fourth portion 20 located outside the spacing region 3, the width of the electrode formed on the fourth portion 20 located in the spacing 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 spacing region 3 in the second direction B. At this time, it is beneficial to improve the ability of the electrode formed on the fourth portion 20 located in the spacing region 3 to collect the current generated in the spacing region 3, realize more efficient transmission of the current, and reduce the loss of the current.

[0051] See also Figures 1 to 3 , combined with the above description, since the number of the fourth parts 20 located in the spacing area 3 is reduced, when the area of ​​the spacing area 3 is constant, compared with when the number of the fourth parts 20 located in the spacing area 3 is not reduced, the present application can increase the width of the connection part 120 located in the spacing area 3. Further, when the width of the connection part 120 is increased, the width of the electrode formed in the connection part 120 later can be increased and / or the number of electrodes formed in the connection part 120 later can be increased. At this time, not only the area of ​​the blank area in the spacing area 3 is further reduced, and the utilization rate of the spacing area 3 is improved, but also the ability of the electrode formed on the connection part 120 to collect the current generated in the corresponding area on the semiconductor substrate is improved, so as to achieve more efficient transmission of the current and reduce the loss of the current.

[0052] As a possible implementation, see Figure 1, along the second direction B, the width W4 of the connection portion 120 is greater than or equal to 150 μm and less than or equal to 500 μm. Exemplarily, the width W4 of the connection portion 120 may 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] See also Figure 1 and Figure 2 , compared to the shortest distance between the fourth portion 20 located in the spacing region 3 and another fourth portion 20 adjacent to it in the second direction B in the second direction B, which is equal to the distance between two adjacent fourth portions 20 located outside the spacing region 3; and / or, in the spacing region 3, the third portion 12 and the fourth portion 20 of opposite conductivity types are not arranged alternately along the second direction B. In the present application, the number of the third portion 12 and / or the fourth portion 20 in the spacing region 3 is reduced, so when the width of the connecting portion 120 is within the above value range, it can compensate for the reduction in the area of ​​the first doped semiconductor layer 1 caused by the reduction in the number of the third portion 12 located in the spacing region 3, so as to enhance the conductivity, light absorption and charge separation of the first doped semiconductor layer 1, thereby improving the battery efficiency of the back contact battery. Further, in the actual back contact battery, the connecting portion 120 is used to form an electrode. Therefore, when the width of the connecting portion 120 is within the above value range, the width of the electrode formed on the connecting portion 120 in the second direction B is also within the above value range. At this time, it is beneficial to improve the ability of the electrode formed on the connecting portion 120 to collect the current generated in the corresponding area on the semiconductor substrate, realize more efficient transmission of the current, and reduce the loss of the current.

[0054] As a possible implementation, see Figure 2 and Figure 3 , the number of electrodes disposed in the connection portion 120 is greater than or equal to 1. The number of electrodes disposed in the connection portion 120 can be set according to actual conditions, which increases selectivity, enables the back contact battery to adapt to different application scenarios, and expands its scope of application. Further, when the number of electrodes disposed in the connection portion 120 is greater than 1, the current transmission channel is increased, and the current transmission efficiency is improved.

[0055] For example, see Figure 2 , a first polarity collector electrode 6 is disposed on the connecting portion 120. Figure 3 Two first polarity collecting electrodes 6 spaced apart along the second direction B are provided on the connecting portion 120 .

[0056] As a possible implementation, see Figure 1 , along the first direction A, the minimum distance L3 between the second portion 11 and the first portion 10 is greater than or equal to 1 mm and less than or equal to 5 mm. Exemplarily, the minimum distance L3 may 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] See also Figure 1 and Figure 2 When actually manufacturing a back-contact cell, the second part 11 is used to form an electrical connection structure (such as a pad 5). Since the minimum distance L3 between the second part 11 and the first part 10 is within the above-mentioned value range, the pad 5 formed later is away from the first part 10 adjacent to the edge of the back-contact cell, so that the pad 5 is away from the edge of the back-contact cell. At this time, in the process of later manufacturing photovoltaic modules, the interconnection member (such as a solder strip) connected to the pad 5 can be kept away from the edge of the back-contact cell to avoid the occurrence of hidden cracks in the back-contact cell caused by factors such as the roughness of the edge of the back-contact cell itself and the stress concentration caused by the solder strip during the connection process, thereby improving the yield rate and reliability of the photovoltaic module. Furthermore, when the pad 5 is away from the edge of the back-contact cell, both sides of the pad 5 along the first direction A can be connected to the collector electrodes, and at this time, the pad 5 can collect the carriers collected by the collector electrodes located on both sides thereof. Compared with the case where the pad 5 is arranged at the edge of the back contact battery and only one side of the pad 5 is connected to the collector electrode, the present application shortens the transmission distance of the carriers and reduces the current loss.

[0058] As a possible implementation, see Figure 1 , along the second direction B, the length L4 of the second portion 11 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.

[0059] See also Figure 1 and Figure 2 In the actual back contact cell, the second part 11 is used to form an electrical connection structure (such as a soldering pad 5). Since the length L4 of the second part 11 is within the above value range, the length of the soldering pad 5 formed later is also within the above value range. Compared with the case where the length of the soldering pad 5 is less than 1 mm, in the process of later manufacturing photovoltaic modules, the connection strength between the soldering pad 5 in this application and the interconnection member (such as a soldering strip) can be improved to ensure the welding tension, thereby improving the firmness of the connection between the interconnection member and the back contact cell to ensure the yield rate of the photovoltaic module.

[0060] As a possible implementation, see Figure 1The first doped semiconductor layer 1 further includes: a fifth portion 13 extending along the first direction A, the fifth portion 13 being connected to a side of the second portion 11 away from the first portion 10. The sum of the number of the third portions 12 intersecting a side of the second portion 11 adjacent to the first portion 10 is less than the sum of the number of the fifth portions 13 intersecting a side of the second portion 11 away from the first portion 10.

[0061] For example, see Figure 1 , the number of the third parts 12 intersecting the side of the second part 11 adjacent to the first part 10 is three, and the number of the fifth parts 13 intersecting the side of the second part 11 away from the first part 10 is four. Further, when the back contact battery is manufactured later, both the third part 12 and the fifth part 13 can be used to form the first polarity collector electrode 6.

[0062] In a second aspect, an embodiment of the present invention further provides a photovoltaic module, which includes a battery string and an encapsulation layer, wherein the battery string is formed by connecting a plurality of back-contact batteries described in the above technical solution, and the encapsulation layer is used to cover the surface of the battery string.

[0063] The beneficial effects of the photovoltaic module provided by the embodiment of the present invention are the same as the beneficial effects of the back-contact battery described in the above technical solution, and will not be described in detail here.

[0064] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A back contact battery, characterized in that: include: A semiconductor substrate including a first surface and a second surface opposite to 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 is located on a side of the first portion away from the edge; a spacing area is provided between the first portion and the second portion; A third portion is located in the spacing area and extends 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 region with the fourth portion located outside the spacing region; In the second direction, the shortest distance between the fourth portion located in the spacing area and another fourth portion adjacent to it in the second direction is greater than the distance between two adjacent fourth portions located outside the spacing area.

2. The back contact cell 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 break portion is located between the discontinuous portion and the first portion.

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

5. The back contact cell 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 cell 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 cell 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 cell 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 distant from the first portion.

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

10. A photovoltaic module, characterized in that: The photovoltaic module comprises: A battery string, wherein the battery string is 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.

Images