Solar cell, photovoltaic module and photovoltaic system

Abstract

The invention is applicable to the field of photovoltaic technology, and provides a solar cell, a photovoltaic module and a photovoltaic system.The solar cell comprises a silicon substrate, and at least one set of repetitive units are arranged on the front face or the back face of the silicon substrate; each repetitive unit comprises a first doped layer and a second doped layer which are adjacent to each other or arranged at an interval, the polarity of the second doped layer is opposite to that of the first doped layer, and an electrically insulated spacer region is arranged between the first doped layer and the second doped layer; the repeating unit further comprises a stacking area and a grid line, a third doping layer is stacked on the first doping layer, the stacking area of the third doping layer and the first doping layer is the stacking area, the polarity of the third doping layer is the same as that of the second doping layer, and the third doping layer and the second doping layer are conductively communicated through the grid line. The third doped layer and the first doped layer are not conductively communicated through the grid line. When reverse voltage is applied to the two ends of the solar cell, composite leakage current with appropriate magnitude can be generated, and efficient transmission of current and effective control of heating are achieved.

Description

Technical Field

[0001] The invention belongs to the field of photovoltaic technology, and in particular relates to a solar cell, a photovoltaic module and a photovoltaic system. Background Art

[0002] Photovoltaic modules composed of multiple cells are usually installed in open areas with plenty of sunshine. In long-term use, it is inevitable that flying birds, dust, fallen leaves and other obstructions will fall on the photovoltaic modules. These obstructions will form shadows on the photovoltaic modules. In large photovoltaic module arrays, the row spacing is not suitable and shadows can be formed on each other. Due to the existence of local shadows, the current and voltage of some solar cell chips in the photovoltaic module have changed. Conventional solar cells have diode characteristics, and the obscured cells are reverse biased, which increases the product of the local current and voltage of the photovoltaic module, and its power consumption is extremely high, resulting in local temperature rise on these photovoltaic modules. Defects in some cell chips in the photovoltaic module may also cause the module to heat up locally during operation. This phenomenon is called the "hot spot effect". Therefore, photovoltaic modules with existing batteries have a high risk of hot spots in actual operation. After being packaged into photovoltaic modules, the hot spot effect may reduce the power of the module and bring safety issues such as local temperature rise. In related technologies, the risk of hot spots in photovoltaic modules is often avoided by setting bypass diodes, but this method will significantly reduce the power of the modules. Therefore, it is urgent to use other technical means to reduce the "hot spot effect" while maintaining the high power output of the modules. Summary of the invention

[0003] The present invention provides a solar cell, a photovoltaic module and a photovoltaic system, aiming to solve the problem of how to reduce the "hot spot effect" while maintaining the high power output of the module.

[0004] The present invention is implemented as follows: a solar cell comprises a silicon substrate, at least one set of repeating units is arranged on the front side or the back side of the silicon substrate;

[0005] The repeating unit comprises a first doping layer and a second doping layer which are adjacent or spaced apart, the second doping layer has a polarity opposite to that of the first doping layer, and an electrically insulating spacer is provided between the first doping layer and the second doping layer;

[0006] The repeating unit also includes a stacking area and a gate line. A third doping layer is stacked on the first doping layer. The area where the third doping layer and the first doping layer are stacked is the stacking area. The third doping layer and the second doping layer have the same polarity. The third doping layer and the second doping layer are conductively connected through the gate line, and the third doping layer and the first doping layer are not conductively connected through the gate line.

[0007] Optionally, the first doping layer and the second doping layer are adjacent or spaced apart along a first direction, the stacking region is arranged between the adjacent first doping layer and the second doping layer, the stacking region is connected to the first doping layer, and the gate line extends along the first direction to connect the adjacent third doping layer and the second doping layer.

[0008] Optionally, the first doping layer and the second doping layer are alternately arranged along a first direction, the second direction is perpendicular to the first direction, the first doping layer extends a convex position along the first direction, the adjacent second doping layer is provided with a concave position corresponding to the convex position, the third doping layer is provided on the convex position, and the gate line extends along the second direction and is respectively provided on the third doping layer and the second doping layer.

[0009] Optionally, the third doping layer extends in the opposite direction to the protruding direction of the convex position.

[0010] Optionally, the first direction and the second direction are perpendicular to each other, the first doping layer includes a first portion spaced apart along the first direction and a second portion extending along the first direction, and the second portion is connected to one end of the first portion;

[0011] The second doping layer includes a third portion spaced apart along the first direction and a fourth portion extending along the first direction, wherein the fourth portion is connected to one end of the third portion;

[0012] The first doping layer and the second doping layer are arranged opposite to each other, and the first portion and the third portion are arranged adjacent to or spaced apart in a first direction;

[0013] The stacked region is connected to the second portion, and the gate line extends along the second direction and is disposed on the third doping layer and the second doping layer.

[0014] Optionally, the first direction and the second direction are perpendicular to each other, the first doped layer includes a first portion and a fifth portion spaced apart along the first direction, and a second portion extending along the first direction, the length of the fifth portion along the second direction is less than the length of the first portion along the second direction, the second portion is connected to one end of the first portion and the fifth portion, and the first portion and the fifth portion are located on the same side of the second portion;

[0015] The second doping layer includes a third portion spaced apart along the first direction and a fourth portion extending along the first direction, wherein the fourth portion is connected to one end of the third portion;

[0016] The first doping layer and the second doping layer are arranged opposite to each other, and the first portion and the third portion are adjacent to or spaced apart in a first direction, and the fifth portion is opposite to the third portion;

[0017] The stacked region is connected to the fifth portion, and the gate line extends along the second direction and is disposed on the third doping layer and the second doping layer.

[0018] Optionally, a plurality of groups of repeating units are arranged in parallel along the first direction.

[0019] Optionally, the second direction is perpendicular to the first direction, and a plurality of groups of repeating units are arranged in parallel along the second direction.

[0020] Optionally, the stacked region is in a cross shape, and two ends of the cross are respectively connected to the first doped layer and the gate line.

[0021] Optionally, the solar cell further comprises:

[0022] a first passivation layer, the first passivation layer being disposed between the first doped layer and the silicon substrate; and\or

[0023] a second passivation layer, the second passivation layer being disposed between the second doped layer and the silicon substrate; and\or

[0024] A third passivation layer is disposed between the third doped layer and the first doped layer, and the third doped layer is indirectly conductively contacted with the first doped layer through the third passivation layer.

[0025] Optionally, the first doped layer and the third doped layer are indirectly conductively contacted via the third passivation layer to form the stacked region, and a ratio of a total area of ​​the contact regions to an area of ​​the front or back side of the silicon substrate is in a range of 1E-8 to 0.03.

[0026] Optionally, the first doped layer and the second doped layer form a conductive channel in the stacked region, and the first doped layer and the third doped layer release current through the conductive channel, wherein under a reverse bias voltage of -12V or less than -12V, the current density of the solar cell is greater than or equal to 0.1mA / cm 2 , and less than or equal to 5mA / cm 2 .

[0027] Optionally, the first doped layer and the third doped layer form a conductive channel in the stacked region, and the first doped layer and the second doped layer release current through the conductive channel, wherein under a reverse bias voltage of -12V or less than -12V, the current density of the solar cell is in the range of greater than 1.5mA / cm 2 , and less than or equal to 5mA / cm 2 .

[0028] The present invention also provides a photovoltaic assembly, comprising the above-mentioned solar cell.

[0029] The present invention also provides a photovoltaic system, comprising the photovoltaic assembly mentioned above.

[0030] The beneficial effects achieved by the present invention are as follows: by optimizing the structural design of the solar cell, in particular, by forming a stacked region through the first doping layer and the third doping layer, a composite leakage current of appropriate size can be generated when a reverse voltage is applied to both ends of the solar cell, thereby achieving efficient current transmission and effective control of heat generation, ensuring that the conversion efficiency of the solar cell is basically not lost while reducing the risk of hot spots, thereby improving the reliability, power generation capacity and service life of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of a first cross-sectional structure of a stacking region of a solar cell provided by the present invention;

[0032] Figure 2 is a schematic diagram of a second cross-sectional structure of a stacking region of a solar cell provided by the present invention;

[0033] Figure 3 It is a schematic diagram of a third cross-sectional structure of the stacking region of the solar cell provided by the present invention;

[0034] Figure 4 It is a schematic diagram of a fourth cross-sectional structure of a stacking region of a solar cell provided by the present invention;

[0035] Figure 5 is a schematic diagram of a fifth cross-sectional structure of a stacking region of a solar cell provided by the present invention;

[0036] Figure 6 is a sixth cross-sectional structural schematic diagram of the stacking region of the solar cell provided by the present invention;

[0037] Figure 7 is a seventh cross-sectional structural schematic diagram of the stacking region of the solar cell provided by the present invention;

[0038] Figure 8 is a schematic diagram of an eighth cross-sectional structure of a stacking region of a solar cell provided by the present invention;

[0039] Fig. 9 This is a schematic diagram of the first arrangement of the doping layer of the solar cell provided by the present invention;

[0040] Fig.10 This is a schematic diagram of the second arrangement of the doping layer of the solar cell provided by the present invention;

[0041] Fig.11 This is a schematic diagram of the third arrangement of the doping layer of the solar cell provided by the present invention.

[0042] Description of reference numerals:

[0043] 100, solar cell; 110, silicon substrate; 120, first doped layer; 121, first portion; 122, second portion; 123, fifth portion; 130, second doped layer; 131, third portion; 132, fourth portion; 140, first passivation layer; 150, second passivation layer; 160, stacked region; 170, third doped layer; 180, third passivation layer; 190, gate line. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. In addition, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0045] In the description of the present invention, it is necessary to understand that the terms "length", "width", "up", "down", "left", "right", "horizontal", "top", "bottom", etc. indicate orientations or positional relationships based on the orientations 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 orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0046] 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 "plurality" is two or more, unless otherwise clearly and specifically defined.

[0047] 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, an electrical connection, or mutual communication; 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.

[0048] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0049] The disclosure below provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numerals and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments discussed and / or settings. In addition, the examples of various specific processes and materials provided by the present invention, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0050] The present invention optimizes the structural design of the solar cell, especially forms a stacked region through the first doping layer and the third doping layer. When a reverse voltage is applied to both ends of the solar cell, a composite leakage current of appropriate size can be generated, thereby achieving efficient current transmission and effective control of heat generation, ensuring that the conversion efficiency of the solar cell is basically not lost while reducing the risk of hot spots, thereby improving the reliability, power generation capacity and service life of the solar cell.

[0051] Embodiment 1

[0052] like Figures 1 to 11 As shown, this embodiment provides a solar cell 100, including a silicon substrate 110, and at least one group of repeating units is arranged on the front side or the back side of the silicon substrate 110;

[0053] The repeating unit includes a first doping layer 120 and a second doping layer 130 that are adjacent or spaced apart, the second doping layer 130 has a polarity opposite to that of the first doping layer 120, and an electrically insulating spacer is disposed between the first doping layer 120 and the second doping layer 130;

[0054] The repeating unit also includes a stacking region 160 and a gate line 190. A third doping layer 170 is stacked on the first doping layer 120. The region where the third doping layer 170 and the first doping layer 120 are stacked is the stacking region 160. The third doping layer 170 and the second doping layer 130 have the same polarity. The third doping layer 170 and the second doping layer 130 are conductively connected through the gate line 190, and the third doping layer 170 and the first doping layer 120 are not conductively connected through the gate line 190.

[0055] In the solar cell 100 provided in the present application, the "front" and "back" in the front and back sides of the silicon substrate 110 are relative, that is, the "front" refers to the side facing the sunlight along the vertical direction, and the "back" refers to the side facing away from the sunlight along the vertical direction.

[0056] One or more sets of repeating units are arranged on the front or back of the silicon substrate 110, and the first doping layer 120 and the second doping layer 130 are arranged alternately in the repeating unit. The first doping layer 120, the silicon substrate 110 and the second doping layer 130 form a pn junction structure to realize the separation and collection process of the photogenerated carriers of the solar cell 100. In particular, the third doping layer 170 is stacked on the first doping layer 120, and the second doping layer 130 is in contact with the third doping layer 170, so that the first doping layer 120 and the third doping layer 170 are electrically connected.

[0057] It can be understood that the conductive connection between the first doping layer 120 and the third doping layer 170 can be direct contact conduction or tunnel conduction through a passivation layer, which is not limited here.

[0058] The gate line 190 connects the third doping layer 170 and the second doping layer 130 . Through the conduction of the gate line 190 , the first doping layer 120 and the second doping layer 130 are electrically connected.

[0059] When the solar cell 100 generates electricity normally, the first doping layer 120, the second doping layer 130 and the stacking region 160 also perform photoelectric conversion to generate electricity, thereby increasing the power generation efficiency of the solar cell 100. At the component end, when the solar cell 100 is shaded, other solar cells 100 connected in series with it provide reverse current for the shaded solar cell 100, and a composite leakage current of appropriate size can be generated between the first doping layer 120 and the third doping layer 170 of the solar cell 100, thereby reducing the voltage across the shaded solar cell 100 (the voltage is less than the sum of the voltages of other solar cells 100 connected in series with the solar cell 100 and not shaded), and the heat generation efficiency of the solar cell 100 will be reduced, thereby reducing the high heat risk of the hot spot effect.

[0060] Secondly, by deliberately introducing a conductive contact structure in the solar cell 100, it has a protective effect on the hot spot effect caused by defects in the silicon substrate 110 itself (that is, it can reduce the heat generated by the defects), and can reduce or even eliminate the requirements for controlling the defects of the silicon substrate 110. This reduces the risk of hot spots caused by defects in the silicon substrate 110 and improves the manufacturing capacity of the solar cell 100.

[0061] That is to say, by adopting the technical solution of the present application, in the present application, by reasonably designing the area of ​​the conductive contact structure and its position in the solar cell 100, the relationship between the photoelectric conversion efficiency of the solar cell 100 and the control of the hot spot risk can be balanced, and the hot spot risk can be reduced while ensuring that there is no significant loss in the conversion efficiency of the solar cell 100. At the same time, the defect control requirements of the solar cell 100 can be reduced or even eliminated, thereby improving the manufacturing and production capacity of the solar cell 100.

[0062] In addition, for a battery string composed of multiple solar cells 100, compared with the traditional method of connecting bypass diodes in reverse parallel at both ends of the battery string, under the structural design of the solar cell 100 of the present application, it is equivalent to that each solar cell 100 has a bypass circuit, so in some embodiments, in the photovoltaic module, it can reduce or omit the use of bypass diodes to reduce costs. In some embodiments, bypass diodes can also be set in the photovoltaic module, which is not specifically limited here.

[0063] It is particularly noted that the thickness of the first doping layer 120 may be uniform, that is, the thickness of the first doping layer 120 as a whole is consistent, or the thickness of the first doping layer 120 may be non-uniform, that is, the thickness of the first doping layer 120 as a whole is inconsistent, and the thickness of a part of the first doping layer 120 is greater than the thickness of another part of the first doping layer 120. The thickness of the second doping layer 130 and the third doping layer 170 is the same as that of the first doping layer 120, and will not be described in detail here, and the present application does not limit this.

[0064] In some embodiments, the material of the silicon substrate 110 may be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, such as silicon or germanium. The elemental semiconductor material may be single crystal, polycrystalline, amorphous or microcrystalline, for example, silicon may be at least one of single crystal silicon, polycrystalline silicon, amorphous silicon or microcrystalline silicon.

[0065] In some embodiments, the silicon substrate 110 may be an N-type semiconductor substrate, a P-type semiconductor substrate, or an intrinsic semiconductor substrate. The N-type semiconductor substrate is doped with an N-type doping element, and the N-type doping element 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, and the P-type doping element may be any one of the III-group elements such as boron (B), aluminum (Al), gallium (Ga), or indium (In).

[0066] Preferably, in this embodiment, the silicon substrate 110 is a silicon substrate 110 made of single crystal silicon. The ordered crystal structure helps to reduce the scattering and recombination probability of carriers during migration, so that the silicon substrate 110 and the carriers generated by the first doping layer 120 recombine less, thereby increasing the number and mobility of carriers.

[0067] Specifically, in the embodiments of the present application, the second doping layer 130 and the third doping layer 170 have opposite polarity to the first doping layer 120. The first doping layer 120 may be an N-type doping layer, and the second doping layer 130 and the third doping layer 170 may be a P-type doping layer. Of course, the first doping layer 120 may be a P-type doping layer, and the second doping layer 130 and the third doping layer 170 may be an N-type doping layer.

[0068] In this embodiment, by optimizing the structural design of the solar cell 100, especially by forming the stacking region 160 through the first doping layer 120 and the third doping layer 170, when a reverse voltage is applied across the solar cell 100, a composite leakage current of appropriate size can be generated, thereby achieving efficient current transmission and effective control of heat generation, ensuring that the conversion efficiency of the solar cell 100 is basically not lost while reducing the risk of hot spots, thereby improving the reliability, power generation capacity and service life of the solar cell 100.

[0069] Embodiment 2

[0070] Based on the first embodiment, the first doping layer 120 and the second doping layer 130 are adjacent or spaced apart along the first direction, the stacking region is arranged between the adjacent first doping layers 120 and the second doping layers 130, and the gate line 190 extends along the first direction to connect the adjacent third doping layer 170 and the second doping layer 130.

[0071] like Fig. 9 As shown, the vertical direction is the first direction, and the horizontal direction is the second direction. The first doped layer 120 and the second doped layer 130 are arranged in a spaced relationship along the vertical direction, and a spacer is arranged between the first doped layer 120 and the second doped layer 130. The spacer can be a spacer where the first doped layer 120 and the second doped layer 130 are electrically insulated, or a spacer where a poor conductor is arranged between the first doped layer 120 and the second doped layer 130, which is not limited here.

[0072] The stacked region is disposed between adjacent first doping layers 120 and second doping layers 130. Specifically, the first doping layer 120 may extend toward the adjacent second doping layer 130, but may not extend to contact the second doping layer 130. The third doping layer 170 is disposed on the portion extending from the first doping layer 120, and the gate line 190 extends vertically to connect the third doping layer 170 and the adjacent second doping layer 130.

[0073] Alternatively, the third doping layer 170 is disposed on a portion of the first doping layer 120 , and the gate line 190 vertically extends to connect the third doping layer 170 and the adjacent second doping layer 130 .

[0074] The shape of the stacked region 160 may be in different forms. For example, the width of the stacked region 160 may be greater than or less than the width of the first doping layer 120 and the second doping layer 130 , or the stacked region 160 may be in a trapezoidal, triangular, or other shapes, which are not limited here.

[0075] Embodiment 3

[0076] On the basis of embodiment one, the first doping layer 120 and the second doping layer 130 are alternately arranged along the first direction, the second direction is perpendicular to the first direction, the first doping layer 120 extends a convex position along the first direction, the adjacent second doping layer 130 is provided with a concave position corresponding to the convex position, the third doping layer 170 is arranged on the convex position, and the gate line 190 extends along the first direction and is respectively arranged on the first doping layer 120 and the second doping layer 130.

[0077] like Fig.10 As shown, the vertical direction is the first direction, and the horizontal direction is the second direction. The first doped layer 120 and the second doped layer 130 are arranged in a spaced relationship along the vertical direction, and a spacer is arranged between the first doped layer 120 and the second doped layer 130. The spacer can be a spacer where the first doped layer 120 and the second doped layer 130 are electrically insulated, or a spacer where a poor conductor is arranged between the first doped layer 120 and the second doped layer 130, which is not limited here.

[0078] The stacked region 160 partially extends into the second doping layer 130, that is, the convex position of the first doping layer 120 extends into the second doping layer 130. Since a spacing region is provided between the first doping layer 120 and the second doping layer 130, the first doping layer 120 and the second doping layer 130 cannot be in direct contact with each other, and corresponding to the convex position of the first doping layer 120 extending into the second doping layer 130, the second doping layer 130 is provided with a concave position to avoid direct contact with the first doping layer 120. The third doping layer 170 is provided on the convex position, and the gate line 190 is provided in the horizontal direction to connect the third doping layer 170 and the second doping layer 130.

[0079] Embodiment 4

[0080] Based on the first embodiment, the third doping layer 170 extends in the opposite direction to the direction in which the protrusion is raised.

[0081] like Fig.10 As shown, the third doped layer extends in the opposite direction of the protrusion, thereby increasing the area of ​​the stacking region.

[0082] Embodiment 5

[0083] On the basis of the first embodiment, the first direction and the second direction are perpendicular to each other, the first doping layer 120 includes a first portion 1211 spaced apart along the first direction and a second portion 122 extending along the first direction, and the second portion 122 is connected to one end of the first portion 121;

[0084] The second doping layer 130 includes a third portion 131 spaced apart along the first direction and a fourth portion 132 extending along the first direction, wherein the fourth portion 132 is connected to one end of the third portion 131;

[0085] The first doping layer 120 and the second doping layer 130 are arranged opposite to each other, and the first portion 121 and the third portion 131 are arranged adjacent to or spaced apart in a first direction;

[0086] The stacked region is connected to the second portion. The gate line 190 extends along the second direction and is disposed on the third doping layer 170 and the second doping layer 130 .

[0087] Specifically, the vertical direction is the first direction, and the horizontal direction is the second direction. The first portion 121 of the first doping layer 120 and the third portion 131 of the second doping layer 130 are arranged alternately or at intervals in the vertical direction, and there is a spacing area between the adjacent first portions 121 and the third portions 131. The second portion 122 of the first doping layer 120 and the fourth portion 132 of the second doping layer 130 extend in the vertical direction and are respectively connected to the ends of the first portion 121 and the third portion 131. The first doping layer 120 and the second doping layer 130 are arranged opposite to each other, the second portion 122 and the fourth portion 132 are respectively arranged on opposite sides, there is a spacing area between the adjacent first portions 121 and the fourth portion 132, and there is a spacing area between the adjacent second portions 122 and the third portion 131. The spacing area can be specifically that the first doping layer 120 and the second doping layer 130 are electrically insulated, or a poor conductor is arranged between the two, which is not limited here.

[0088] like Fig.11 As shown, the stacking region is arranged on the side of the second portion 122 close to the third portion 131. Specifically, the first doping layer 120 may extend a portion on the side of the second portion 122 close to the third portion 131, and the third doping layer 170 is arranged on the extended portion to form the stacking region. The gate line 190 extends horizontally, connecting the third doping layer 170 and the adjacent second doping layer 130.

[0089] Embodiment 6

[0090] On the basis of the first embodiment, the first direction and the second direction are perpendicular to each other, the first doping layer 120 includes a first portion 121 and a fifth portion 123 spaced apart along the first direction, and a second portion 122 extending along the first direction, the length of the fifth portion 123 along the second direction is less than the length of the first portion 121 along the second direction, the second portion 122 is connected to one end of the first portion 121 and the fifth portion 123, and the first portion 121 and the fifth portion 123 are located on the same side of the second portion 122;

[0091] The second doping layer 130 includes a third portion 131 spaced apart along the first direction and a fourth portion 132 extending along the first direction, wherein the fourth portion 132 is connected to one end of the third portion 131;

[0092] The first doping layer 120 and the second doping layer 130 are arranged opposite to each other, and the first portion 121 and the third portion 123 are arranged adjacent to or spaced apart in a first direction, and the fifth portion 123 is directly opposite to the third portion 131;

[0093] The stacked region is connected to the fifth portion. The gate line 190 extends along the second direction and is disposed on the third doping layer 170 and the second doping layer 130 .

[0094] like Fig.11 As shown, the stacking region 160 is connected to the fifth portion 123. Specifically, the first doping layer 120 may extend a portion on the side of the second portion 122 close to the third portion 131, and the third doping layer 170 is partially disposed on the extended portion to form the stacking region, and the portion without the third doping layer 170 is the fifth portion 123, and the fifth portion 123 is connected to the second portion 122. The gate line 190 extends horizontally, connecting the third doping layer 170 and the adjacent second doping layer 130.

[0095] Embodiment 7

[0096] On the basis of the second to sixth embodiments, a plurality of groups of repeating units are arranged in parallel along the first direction.

[0097] Multiple groups of repeating units are arranged in parallel along the first direction to form an array. Each repeating unit includes an alternating structure of multiple first doping layers 120 and second doping layers 130, ensuring uniformity and high efficiency of the entire array.

[0098] Embodiment 8

[0099] On the basis of the second to seventh embodiments, a plurality of groups of repeating units are arranged in parallel along the second direction.

[0100] Multiple groups of repeating units are arranged in parallel along the second direction to form an array. Each repeating unit includes an alternating structure of multiple first doping layers 120 and second doping layers 130, ensuring uniformity and high efficiency of the entire array.

[0101] Embodiment 9

[0102] like Figure 5 As shown, based on the first embodiment, the stacking region 160 is in a cross shape, and the protruding parts of the stacking region 160 are respectively connected to the first doping layer 120 and the gate line 190 .

[0103] The stacking region 160 is presented in a "cross" shape, in which the vertical and horizontal protrusions are connected to the first doping layer 120 and the second doping layer 130, respectively. This design makes the stacking region 160 relatively narrow, but the area of ​​the stacking region 160 itself is large. The design of the cross-shaped stacking region 160 makes the stacking region 160 relatively narrow, which means that the probability of interface recombination is reduced. Interface recombination usually leads to the loss of photogenerated carriers and reduces the efficiency of the battery. At the same time, the cross-shaped stacking region 160 itself has a large area and can provide sufficient reverse leakage current, which is crucial to achieving efficient current conduction and maintaining the working performance of the battery.

[0104] Embodiment 10

[0105] Based on the first embodiment, the solar cell 100 further includes:

[0106] A first passivation layer 140, the first passivation layer 140 is disposed between the first doping layer 120 and the silicon substrate 110; and\or

[0107] A second passivation layer 150, the second passivation layer 150 is disposed between the second doping layer 130 and the silicon substrate 110; and\or

[0108] The third passivation layer 180 is disposed between the third doping layer 170 and the first doping layer 120 . The third doping layer 170 is in indirect conductive contact with the first doping layer 120 via the third passivation layer 180 .

[0109] The first doping layer 120, the second doping layer 130 and the third doping layer 170 form a conductive contact as follows:

[0110] like Figure 1 As shown, the first doping layer 120 and the second doping layer 130 cover the front side or the back side of the silicon substrate 110, and the first doping layer 120 and the second doping layer 130 are alternately arranged. The third doping layer 170 partially covers the first doping layer 120, and the first doping layer 120 and the third doping layer 170 form a direct conductive contact.

[0111] like Figure 2 As shown, the first doping layer 120 and the second doping layer 130 cover the front side or the back side of the silicon substrate 110, the first doping layer 120 and the second doping layer 130 are alternately arranged, and the first passivation layer 140 is arranged between the first doping layer 120 and the silicon substrate 110. The third doping layer 170 partially covers the first doping layer 120, and the first doping layer 120 and the third doping layer 170 form a direct conductive contact.

[0112] like Figure 3 As shown, the first doping layer 120 and the second doping layer 130 cover the front side or the back side of the silicon substrate 110, the first doping layer 120 and the second doping layer 130 are alternately arranged, and the second passivation layer 150 is arranged between the second doping layer 130 and the silicon substrate 110. The third doping layer 170 partially covers the first doping layer 120, and the first doping layer 120 and the third doping layer 170 form a direct conductive contact.

[0113] like Figure 4 As shown, the first doping layer 120 and the second doping layer 130 cover the front side or the back side of the silicon substrate 110, the first doping layer 120 and the second doping layer 130 are alternately arranged, the first passivation layer 140 is arranged between the first doping layer 120 and the silicon substrate 110, and the second passivation layer 150 is arranged between the second doping layer 130 and the silicon substrate 110. The third doping layer 170 partially covers the first doping layer 120, and the first doping layer 120 and the third doping layer 170 form a direct conductive contact.

[0114] like Figure 5 As shown, the first doping layer 120 and the second doping layer 130 cover the front side or the back side of the silicon substrate 110, and the first doping layer 120 and the second doping layer 130 are alternately arranged. The third doping layer 170 partially covers the first doping layer 120, and the third passivation layer 180 is arranged between the third doping layer 170 and the first doping layer 120, and the first doping layer 120 and the third doping layer 170 form an indirect conductive contact.

[0115] like Figure 6 As shown, the first doping layer 120 and the second doping layer 130 cover the front side or the back side of the silicon substrate 110, the first doping layer 120 and the second doping layer 130 are alternately arranged, and the first passivation layer 140 is arranged between the first doping layer 120 and the silicon substrate 110. The third doping layer 170 partially covers the first doping layer 120, and the third passivation layer 180 is arranged between the third doping layer 170 and the first doping layer 120, and the first doping layer 120 and the third doping layer 170 form an indirect conductive contact.

[0116] like Figure 7As shown, the first doping layer 120 and the second doping layer 130 cover the front side or the back side of the silicon substrate 110, the first doping layer 120 and the second doping layer 130 are alternately arranged, and the second passivation layer 150 is arranged between the second doping layer 130 and the silicon substrate 110. The third doping layer 170 partially covers the first doping layer 120, and the third passivation layer 180 is arranged between the third doping layer 170 and the first doping layer 120, and the first doping layer 120 and the third doping layer 170 form an indirect conductive contact.

[0117] like Figure 8 As shown, the first doping layer 120 and the second doping layer 130 cover the front side or the back side of the silicon substrate 110, the first doping layer 120 and the second doping layer 130 are alternately arranged, the first passivation layer 140 is arranged between the first doping layer 120 and the silicon substrate 110, and the second passivation layer 150 is arranged between the second doping layer 130 and the silicon substrate 110. The third doping layer 170 partially covers the first doping layer 120, and the third passivation layer 180 is arranged between the third doping layer 170 and the first doping layer 120, and the first doping layer 120 and the third doping layer 170 form an indirect conductive contact.

[0118] Embodiment 11

[0119] Based on the first embodiment, the first doped layer 120 and the third doped layer 170 are indirectly conductively contacted through the third passivation layer 180 to form a stacked region 160, and the ratio of the total area of ​​the stacked region 160 to the area of ​​the front or back side of the silicon substrate 110 is in the range of 1E-8 to 0.03.

[0120] The first doping layer 120 and the third doping layer 170 are in direct conductive contact to form a stacking region 160, and the ratio of the total area of ​​the stacking region 160 to the area of ​​the front or back side is in the range of 1E-8 to 0.03. The first doping layer 120 and the third doping layer 170 are in indirect conductive contact to form a stacking region 160 through the third passivation layer 180, and the ratio of the total area of ​​the stacking region 160 to the area of ​​the front or back side is in the range of 1E-8 to 0.03. The first doping layer 120 and the second doping layer 130 are in indirect conductive contact to form a stacking region 160 through the second passivation layer 150, and the ratio of the total area of ​​the stacking region 160 to the area of ​​the front or back side is in the range of 1E-8 to 0.03.

[0121] Thus, setting the area ratio of the stacked region 160 within this reasonable range can avoid the conductive stacked region 160 from accounting for too small a total area ratio, which results in too high a reverse bias voltage, and can also avoid the conductive stacked region 160 from accounting for too large an area ratio, which seriously affects the efficiency of the solar cell 100, that is, the efficiency of the solar cell 100 can be ensured while lowering the reverse conduction threshold. Reasonable contact area distribution can ensure that the current is evenly distributed inside the solar cell 100, avoid local overheating and current concentration, and further improve the performance and stability of the cell.

[0122] Specifically, in such an embodiment, the ratio of the area of ​​the stacking region 160 to the area of ​​the front side or the back side may be 1E-8, 0.01, 0.02, 0.03 or any other value between 1E-8 and 0.03, which is not specifically limited herein.

[0123] Embodiment 12

[0124] On the basis of the first embodiment, the first doping layer 120 and the third doping layer 170 form a conductive channel in the stacking region 160, and the first doping layer 120 and the third doping layer 170 release current through the conductive channel, wherein, under a reverse bias voltage of -12V or less than -12V, the current density of the solar cell 100 is greater than or equal to 0.1mA / cm 2 , and less than or equal to 5mA / cm 2 .

[0125] The first doping layer 120 and the third doping layer 170 form a conductive channel in the stacking region 160, and the first doping layer 120 and the third doping layer 170 release current through the conductive channel. Under a reverse bias voltage of -12V or less, the current density of the solar cell 100 is in the range of 0.1 to 5 mA / cm 2 The reverse bias voltage of -12V or less than -12V is a standard test voltage. Within this current density range, the internal reaction of the solar cell 100 is complete, and the solar cell 100 has a high energy density and power density.

[0126] Embodiment 13

[0127] On the basis of the twelfth embodiment, the first doping layer 120 and the third doping layer 170 form a conductive channel in the stacking region 160, and the first doping layer 120 and the third doping layer 170 release current through the conductive channel, wherein under a reverse bias voltage of -12V or less than -12V, the current density of the solar cell 100 is greater than 1.5mA / cm 2 , and less than or equal to 5mA / cm 2 .

[0128] The first doping layer 120 and the third doping layer 170 form a conductive channel in the stacking region 160, and the first doping layer 120 and the third doping layer 170 release current through the conductive channel. Under a reverse bias voltage of -12V or less, the current density of the solar cell 100 is greater than 1.5mA / cm 2 Less than or equal to 5mA / cm 2 The reverse bias voltage of -12V or less than -12V is a standard test voltage. Within this current density range, the internal reaction of the solar cell 100 is complete, and the solar cell 100 has a high energy density and power density.

[0129] Specifically, the current density is defined as the current measured at a reverse bias voltage of −12 V or less divided by the projected area of ​​the front or back side of the solar cell 100 .

[0130] Embodiment 14

[0131] This embodiment provides a photovoltaic assembly, including the solar cell 100 of the above embodiment.

[0132] Typically, multiple solar cells 100 in a photovoltaic module can be connected in series in sequence to form a battery string. The battery strings can be connected in series, in parallel, or in a combination of series and parallel to achieve current bus output. For example, the connection between the solar cells 100 can be achieved by welding welding strips, and the connection between the battery strings can be achieved by bus bars.

[0133] The beneficial effects of the photovoltaic module of this embodiment are equivalent to the beneficial effects of the above-mentioned solar cell 100, and will not be described in detail here.

[0134] Embodiment 15

[0135] This embodiment provides a photovoltaic system, including the photovoltaic assembly of the above embodiment.

[0136] The beneficial effects of the photovoltaic system of this embodiment are equivalent to the beneficial effects of the above-mentioned solar cell 100, and will not be described in detail here.

[0137] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A back contact solar cell structure, characterized in that: The invention comprises a silicon substrate, wherein at least one set of repeating units is arranged on the front side or the back side of the silicon substrate; The repeating unit comprises a first doping layer and a second doping layer which are adjacent or spaced apart, the second doping layer has a polarity opposite to that of the first doping layer, and an electrically insulating spacer is provided between the first doping layer and the second doping layer; The repeating unit also includes a stacking area and a gate line. A third doping layer is stacked on the first doping layer. The area where the third doping layer and the first doping layer are stacked is the stacking area. The third doping layer and the second doping layer have the same polarity. The third doping layer and the second doping layer are conductively connected through the gate line, and the third doping layer and the first doping layer are not conductively connected through the gate line.

2. The back contact solar cell structure according to claim 1, characterized in that: The first doping layer and the second doping layer are adjacent or spaced apart along a first direction, the stacking region is arranged between adjacent first doping layers and second doping layers, and the gate line extends along the first direction to connect the adjacent third doping layer and the second doping layer.

3. The back contact solar cell structure according to claim 1, characterized in that: The first doping layer and the second doping layer are alternately arranged along a first direction, the second direction is perpendicular to the first direction, the first doping layer extends a convex position along the first direction, the adjacent second doping layer is provided with a concave position corresponding to the convex position, the third doping layer is arranged on the convex position, and the gate line extends along the second direction and is respectively arranged on the third doping layer and the second doping layer.

4. The back contact solar cell structure according to claim 3, characterized in that: The third doping layer extends in the opposite direction to the direction in which the protrusion is raised.

5. The back contact solar cell structure according to claim 1, characterized in that: The first direction and the second direction are perpendicular to each other, the first doping layer comprises a first portion spaced apart along the first direction and a second portion extending along the first direction, the second portion being connected to one end of the first portion; The second doping layer includes a third portion spaced apart along the first direction and a fourth portion extending along the first direction, wherein the fourth portion is connected to one end of the third portion; The first doping layer and the second doping layer are arranged opposite to each other, and the first portion and the third portion are arranged adjacent to or spaced apart in a first direction; The stacked region is connected to the second portion, and the gate line extends along the second direction and is disposed on the third doping layer and the second doping layer.

6. The back contact solar cell structure according to claim 1, characterized in that: The first direction and the second direction are perpendicular to each other, the first doped layer includes a first portion and a fifth portion spaced apart along the first direction, and a second portion extending along the first direction, the length of the fifth portion along the second direction is less than the length of the first portion along the second direction, the second portion is connected to one end of the first portion and the fifth portion, and the first portion and the fifth portion are located on the same side of the second portion; The second doping layer includes a third portion spaced apart along the first direction and a fourth portion extending along the first direction, wherein the fourth portion is connected to one end of the third portion; The first doping layer and the second doping layer are arranged opposite to each other, and the first portion and the third portion are adjacent to or spaced apart in a first direction, and the fifth portion is opposite to the third portion; The stacked region is connected to the fifth portion, and the gate line extends along the second direction and is disposed on the third doping layer and the second doping layer.

7. The back contact solar cell structure according to any one of claims 2 to 6, characterized in that: A plurality of groups of repeating units are arranged in parallel along the first direction.

8. The back contact solar cell structure according to any one of claims 2 to 6, characterized in that: The second direction is perpendicular to the first direction, and a plurality of groups of repeating units are arranged in parallel along the second direction.

9. The back contact solar cell structure according to claim 1, characterized in that: The stacked region is in a "cross" shape, and two ends of the "cross" are respectively connected to the first doped layer and the gate line.

10. The back contact solar cell structure according to claim 1, characterized in that: The solar cell also includes: a first passivation layer, the first passivation layer being disposed between the first doped layer and the silicon substrate; and\or a second passivation layer, the second passivation layer being disposed between the second doped layer and the silicon substrate; and\or A third passivation layer is disposed between the third doped layer and the first doped layer, and the third doped layer is indirectly conductively contacted with the first doped layer through the third passivation layer.

11. The back contact solar cell structure according to claim 10, characterized in that: The first doped layer and the third doped layer are in indirect conductive contact through the third passivation layer to form the stacked region, and the ratio of the total area of ​​the contact region to the area of ​​the front side or the back side of the silicon substrate is in the range of 1E-8 to 0.

03.

12. The back contact solar cell structure according to claim 1, characterized in that: The first doped layer and the third doped layer form a conductive channel in the contact area, and the first doped layer and the third doped layer release current through the conductive channel, wherein under a reverse bias voltage of -12V or less than -12V, the current density of the solar cell is greater than or equal to 0.1mA / cm 2 , and less than or equal to 5mA / cm 2 .

13. The back contact solar cell structure according to claim 12, characterized in that: The first doped layer and the third doped layer form a conductive channel in the contact area, and the first doped layer and the third doped layer release current through the conductive channel, wherein under a reverse bias voltage of -12V or less than -12V, the current density of the solar cell is in the range of greater than 1.5mA / cm 2 , and less than or equal to 5mA / cm 2 .

14. A photovoltaic module, characterized in that: A solar cell comprising the solar cell according to any one of claims 1 to 13.

15. A photovoltaic system, characterized in that: Comprising the photovoltaic module described in claim 14.

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