A back contact solar cell, cell assembly and photovoltaic system

Abstract

The utility model is suitable for photovoltaic technical field provides a kind of back contact solar cell, battery component and photovoltaic system, back contact solar cell includes: silicon chip, the back of silicon chip includes the first area and the second area of alternative interval arrangement;First doped layer being arranged at first area;With the first electrode of first doped layer connection;Second doped layer being arranged at second area;With the second electrode of second doped layer connection;At least part second doped layer has the leakage contact portion extending to first doped layer, first doped layer includes the first sub-doped layer of composite contact being formed with leakage contact portion, the second sub-doped layer of not being formed with composite contact of leakage contact portion, the width of at least one first sub-doped layer along first direction is greater than the width of second sub-doped layer along first direction.The back contact solar cell of the utility model can improve power generation, especially can improve power generation under weak light condition.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic technology, and in particular to a back-contact solar cell, a battery module and a photovoltaic system. Background Technology

[0002] A solar cell is a semiconductor device that converts solar energy into electrical energy. Under sunlight, a photocurrent is generated inside the solar cell, which outputs electrical energy through electrodes. In recent years, solar cell manufacturing technology has continuously advanced, production costs have decreased, and conversion efficiency has continuously improved. Solar cell power generation has become increasingly widespread and is an important energy source for electricity supply. Among them, the interdigitated back contact (IBC) solar cell, also known as a cross-linked back contact solar cell, has both its positive and negative electrode grids designed on the back of the cell. This completely avoids the shading of the metal grids on the front surface, eliminating optical losses caused by grid shading. At the same time, the electrode grids can be designed to be wider than existing ones, reducing series resistance losses and thus significantly improving cell conversion efficiency.

[0003] In related technologies, the back side of a silicon wafer in a back-contact solar cell typically includes alternating first and second regions. The first region has a first doped layer, and the second region has a second doped layer. The doping polarities of the first and second doped layers are opposite. To control hot spot effects when the cell is shaded, a predetermined number of second doped layers are typically extended locally to form leakage contacts. These leakage contacts extend onto the first doped layer and form a composite contact. When the cell is shaded, and the leakage current of the back-contact solar cell reaches its maximum power point current, the leakage contacts of the second doped layer become conductive with the first doped layer, reducing the voltage across the shaded back-contact solar cell. This reduces the heat generation power of the back-contact solar cell and thus lowers the risk of hot spots. However, the width of the second doped layer is usually uniform, and the electrodes on the first doped layer easily overlap with the leakage contacts of the second doped layer. During normal operation of the back-contact solar cell, leakage can easily occur between the electrodes on the first doped layer and the second doped layer, affecting the power generation of the back-contact solar cell. Utility Model Content

[0004] This invention provides a back-contact solar cell, which aims to solve the problem that leakage current easily occurs between the electrode on the first doped layer and the second doped layer in the prior art back-contact solar cells, thereby affecting the power generation of the back-contact solar cell.

[0005] This invention is implemented by providing a back-contact solar cell, comprising:

[0006] A silicon wafer, the back side of which includes a first region and a second region alternately spaced along a first direction;

[0007] A first doped layer is disposed in the first region;

[0008] A first electrode is disposed on the first doped layer, and the first electrode is connected to the first doped layer;

[0009] A second doped layer is disposed in the second region, wherein the doping polarities of the first doped layer and the second doped layer are opposite; and

[0010] A second electrode is disposed on the second doped layer, and the second electrode is connected to the second doped layer;

[0011] Wherein, at least a portion of the second doped layer has a leakage contact extending onto the first doped layer; the first doped layer includes a first sub-doped layer that forms a composite contact with the leakage contact and a second sub-doped layer that does not form a composite contact with the leakage contact, and at least one of the widths of the first sub-doped layer along the first direction is greater than the width of the second sub-doped layer along the first direction.

[0012] Preferably, the width of any one of the first sub-doped layers along the first direction is greater than the width of the second sub-doped layer along the first direction.

[0013] Preferred options also include:

[0014] An isolation region is disposed between the first region and the second region, wherein the leakage contact portion of the second doped layer extends toward the isolation region and extends onto the first sub-doped layer.

[0015] Preferably, the ratio of the width of the first sub-doped layer along the first direction to the width of the second sub-doped layer along the first direction is 1.1 to 2.5.

[0016] Preferably, the ratio of the width of the first sub-doped layer along the first direction to the width of the second sub-doped layer along the first direction is 1.4 to 1.6.

[0017] Preferably, the width of the first sub-doped layer along the first direction is 165 to 750 micrometers.

[0018] Preferably, the width of the second sub-doped layer along the first direction is 150 to 300 micrometers.

[0019] Preferably, the distance between the first electrode on the first sub-doped layer and the leakage contact portion along the first direction is 30 to 100 micrometers.

[0020] Preferably, the distance between the first electrode on the first sub-doped layer and the leakage contact portion along the first direction is 50 to 60 micrometers.

[0021] Preferably, a dielectric layer is disposed between the leakage contact portion of the second doped layer and the first doped layer, and the leakage contact portion of the second doped layer forms a composite contact with the first doped layer through the dielectric layer; or, the leakage contact portion of the second doped layer directly contacts the first doped layer to form a composite contact.

[0022] This invention provides a battery assembly including the aforementioned back-contact solar cell.

[0023] This invention provides a photovoltaic system, including the aforementioned battery module.

[0024] This utility model provides a back-contact solar cell by providing leakage contact portions extending onto a first doped layer in a portion of a second doped layer. The leakage contact portions overlap with the first doped layer to form a composite contact. The first doped layer includes a first sub-doped layer that forms a composite contact with the leakage contact portions and a second sub-doped layer that does not form a composite contact with the leakage contact portions. The width of at least one first sub-doped layer along a first direction is controlled to be greater than the width of the second sub-doped layer along the first direction. That is, the width of at least one first sub-doped layer along the first direction is wider than the width of the second sub-doped layer along the first direction. This increases the distance from the first electrode on at least one first sub-doped layer to the leakage contact portion, avoids the first electrode from overlapping with the leakage contact portion, and prevents leakage between the first electrode on the first sub-doped layer and the second doped layer from affecting the power generation of the back-contact solar cell during normal operation. This improves the power generation of the back-contact solar cell, especially under low light conditions. Attached Figure Description

[0025] Figure 1 A schematic diagram of the back side of a back-contact solar cell provided for an embodiment of this utility model;

[0026] Figure 2 For along Figure 1 A cross-sectional view of line AA in the middle. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. Examples of embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present utility model, and should not be construed as limiting the present utility model. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining the present utility model and are not intended to limit the present utility model.

[0028] In the description of this utility model, it should be understood that the terms "upper", "lower", "back", "front", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0029] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0030] The following disclosure provides numerous different embodiments or examples for implementing various structures of the present invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention; however, those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0031] Please refer to Figures 1-2 This utility model provides a back-contact solar cell, comprising:

[0032] The back side of the silicon wafer 1 includes a first region 11 and a second region 12 that are alternately spaced along a first direction X.

[0033] A first doped layer 2 is disposed in the first region 11;

[0034] A first electrode 3 is disposed on the first doped layer 2, and the first electrode 3 is connected to the first doped layer 2;

[0035] A second doped layer 4 is provided in the second region 12, wherein the doping polarities of the first doped layer 2 and the second doped layer 4 are opposite; and

[0036] A second electrode 5 is disposed on the second doped layer 4, and the second electrode 5 is connected to the second doped layer 4;

[0037] In this embodiment, at least a portion of the second doped layer 4 has a leakage contact portion 41 extending onto the first doped layer 2; the first doped layer 2 includes a first sub-doped layer 21 that forms a composite contact with the leakage contact portion 41 and a second sub-doped layer 22 that does not form a composite contact with the leakage contact portion 41, wherein at least one of the widths L1 of the first sub-doped layer 21 along the first direction X is greater than the width L2 of the second sub-doped layer 22 along the first direction X.

[0038] In this embodiment of the invention, the back side of the silicon wafer 1 is the side facing away from sunlight when the back-contact solar cell is in operation. There are multiple first regions 11 and multiple second regions 12, and these multiple first regions 11 and multiple second regions 12 are alternately arranged along a first direction X.

[0039] In this embodiment, the first doped layer 2 and the second doped layer 4 are, respectively, a P-type doped layer and an N-type doped layer. When the first doped layer 2 is a P-type doped layer, the first region 11 is a P-type doped region; when the second doped layer 4 is an N-type doped layer, the second region 12 is an N-type doped region. Alternatively, when the first doped layer 2 is an N-type doped layer, the first region 11 is an N-type doped region; the second doped layer 4 is a P-type doped layer, and the second region 12 is a P-type doped region. That is, one of the first region 11 and the second region 12 is a P-type doped region, and the other is an N-type doped region. The P-type doped layer contains P-type elements, and the N-type doped layer contains N-type elements.

[0040] In this embodiment of the present invention, the back contact solar cell can be a back contact solar cell without a main grid or a back contact solar cell with a main grid; when the back contact solar cell is a back contact solar cell without a main grid, the first electrode 3 and the second electrode 5 are fine grids; when the back contact solar cell is a back contact solar cell with a main grid, the first electrode 3 and the second electrode 5 are fine grids or main grids.

[0041] In this embodiment of the invention, the number of second doped layers 4 with leakage contact portions 41 is not limited. The leakage contact portions 41 can be arranged in multiple rows and columns on the back side of the back-contact solar cell. In this embodiment of the invention, the first doped layer 2 is divided into a first sub-doped layer 21 and a second sub-doped layer 22. The first sub-doped layer 21 forms a composite contact with the leakage contact portions 41, creating a leakage composite contact structure. The leakage contact portions 41 of the second doped layer 4 extend onto the first sub-doped layer 21, and overlap with a local area of ​​the first sub-doped layer 21, thus forming a composite contact between the overlapping area of ​​the second doped layer 4 and the first sub-doped layer 21. The second sub-doped layer 22 does not form a composite contact with the second doped layer 4, i.e., the second sub-doped layer 22 does not form a leakage composite contact structure with the second doped layer 4.

[0042] In this embodiment of the invention, a back-contact solar cell is provided with a leakage contact portion 41 extending onto the first doped layer 2 in a portion of the second doped layer 4. The leakage contact portion 41 overlaps with the first doped layer 2 to form a composite contact. The leakage contact portion 41 and the first doped layer 2 form a leakage composite contact structure at their overlap position. At the module end, when the back-contact solar cell is shaded, when the leakage current of the back-contact solar cell reaches the maximum power point current, the leakage contact portion 41 of the second doped layer 4 conducts with the first sub-doped layer 21, which reduces the voltage at both ends of the shaded back-contact solar cell, thereby reducing the heat generation power of the back-contact solar cell and thus reducing the risk of hot spots. By controlling the width L1 of at least one first sub-doped layer 21 along the first direction X to be greater than the width L2 of the second sub-doped layer 22 along the first direction X, that is, by widening the width L1 of at least one first sub-doped layer 21 along the first direction X compared to the width L2 of the second sub-doped layer 22 along the first direction X, the distance D from the first electrode 3 on at least one first sub-doped layer 21 to the leakage contact portion 41 can be increased. This can prevent the first electrode 3 from coinciding with the leakage contact portion 41, and can prevent leakage from occurring between the first electrode 3 on the first sub-doped layer 21 and the second doped layer 4 when the back contact solar cell is generating electricity normally, thereby affecting the power generation of the back contact solar cell, and thus improving the power generation of the back contact solar cell, especially improving the power generation of the back contact solar cell under low light conditions.

[0043] The number of the first sub-doped layer 21 and the second sub-doped layer 22 is unlimited. The number of the first sub-doped layer 21 and the second sub-doped layer 22 can be the same or different.

[0044] As an embodiment of the present invention, the width L1 of any first sub-doped layer 21 along the first direction X is greater than the width L2 of the second sub-doped layer 22 along the first direction X.

[0045] In this embodiment of the invention, the width L1 of all first sub-doped layers 21 along the first direction X is greater than the width L2 of the second sub-doped layer 22 along the first direction X. This increases the distance from the first electrode 3 on each first sub-doped layer 21 to the leakage contact 41, preventing leakage between the first electrode 3 on any first sub-doped layer 21 and the leakage contact 41 of the second doped layer 4, thereby further improving the power generation of the back contact solar cell.

[0046] In some embodiments, the proportion of the number of widened first sub-doped layers 21 to the total number of first doped layers 2 can be controlled to balance multiple effects. Optionally, the width L1 of the first sub-doped layers 21, which accounts for 4% to 30% of the total number of first doped layers, along the first direction X is greater than the width L2 of the second sub-doped layers 22 along the first direction X. Controlling the widening of the first sub-doped layers 21, which accounts for 4% to 30% of the total number of first doped layers, prevents an excessive number of widened first sub-doped layers 21 from affecting the current transmission capability of the cell along the X direction. This reduces leakage current loss between the first electrode 3 and the second doped layer 22 and ensures good lateral current transmission capability of the cell, which is more conducive to improving the power generation capability of the back-contact solar cell.

[0047] As one embodiment of this utility model, it also includes:

[0048] An isolation region 13 is disposed between the first region 11 and the second region 12. The leakage contact portion 41 of the second doped layer 4 extends into the isolation region 13 and extends onto the first sub-doped layer 21.

[0049] In this embodiment, by setting an isolation region 13 between the first region 11 and the second region 12, the physical isolation effect between the second doped layer 4 and the first doped layer 2 is improved. Specifically, the isolation region 13 can be a trench.

[0050] As an embodiment of the present invention, the ratio of the width L1 of the first sub-doped layer 21 along the first direction X to the width L2 of the second sub-doped layer 22 along the first direction X is 1.1 to 2.5.

[0051] In this embodiment, the ratio of the width L1 of the first sub-doped layer 21 along the first direction X to the width L2 of the second sub-doped layer 22 along the first direction X is controlled to be 1.1 to 2.5. This makes the distance from the first electrode 3 on the first sub-doped layer 21 to the leakage contact portion 41 more suitable, preventing leakage between the first electrode 3 on the first sub-doped layer 21 and the second doped layer 4. Moreover, it makes the width difference between the first sub-doped layer 21 and the second sub-doped layer 22 more suitable, which facilitates the fabrication of the first sub-doped layer 21 and the second sub-doped layer 22.

[0052] As one embodiment of the present invention, the ratio of the width L1 of the first sub-doped layer 21 along the first direction X to the width L2 of the second sub-doped layer 22 along the first direction X is 1.4 to 1.6.

[0053] In this embodiment, the ratio of the width L1 of the first sub-doped layer 21 along the first direction X to the width L2 of the second sub-doped layer 22 along the first direction X is further controlled to be 1.4 to 1.6, which further ensures that the distance from the first electrode 3 on the first sub-doped layer 21 to the leakage contact portion 41 is more appropriate, preventing leakage between the first electrode 3 on the first sub-doped layer 21 and the second doped layer 4, and making it easier to prepare the first sub-doped layer 21 and the second sub-doped layer 22.

[0054] As an embodiment of the present invention, the width L1 of the first sub-doped layer 21 along the first direction X is 165 to 750 micrometers.

[0055] In this embodiment, the width L1 of the first sub-doped layer 21 along the first direction X is controlled to be 165 to 750 micrometers. This can prevent leakage between the first electrode 3 and the second doped layer 4 on the first sub-doped layer 21, facilitate the preparation of the first sub-doped layer 21, and facilitate the setting of the first electrode 3.

[0056] As an embodiment of the present invention, the width L2 of the second sub-doped layer 22 along the first direction X is 150 to 300 micrometers.

[0057] In this embodiment, the width L2 of the second sub-doped layer 22 along the first direction X is controlled to be 150-300 micrometers, which facilitates the preparation of the second sub-doped layer 22 and the setting of the second electrode.

[0058] As an embodiment of the present invention, the distance D between the first electrode 3 on the first sub-doped layer 21 and the leakage contact portion 41 along the first direction X is 30 to 100 micrometers.

[0059] In this embodiment, the distance between the first electrode 3 on the first sub-doped layer 21 and the leakage contact 41 along the first direction X is controlled to be 30 to 100 micrometers, so as to ensure that the distance between the first electrode 3 on the first sub-doped layer 21 and the leakage contact 41 is kept at a suitable distance, and to prevent leakage between the first electrode 3 on the first sub-doped layer 21 and the second doped layer 4.

[0060] As an embodiment of the present invention, the distance D between the first electrode 3 on the first sub-doped layer 21 and the leakage contact portion 41 along the first direction X is 50 to 60 micrometers.

[0061] In this embodiment, the distance between the first electrode 3 on the first sub-doped layer 21 and the leakage contact 41 along the first direction X is controlled to be 50-60 micrometers. This further ensures that the distance between the first electrode 3 on the first sub-doped layer 21 and the leakage contact 41 is appropriate, preventing leakage between the first electrode 3 on the first sub-doped layer 21 and the second doped layer 4, and also facilitating processing and fabrication.

[0062] As an embodiment of the present invention, a dielectric layer 6 is provided between the leakage contact portion 41 of the second doped layer 4 and the first doped layer 2, and the leakage contact portion 41 of the second doped layer 4 forms a composite contact with the first doped layer 2 through the dielectric layer 6.

[0063] In this embodiment, the leakage contact 41 and the first doped layer 2 achieve a composite contact through the dielectric layer 6, thereby forming a leakage point (i.e., a leakage composite contact structure). The dielectric layer 6 can be a tunneling oxide layer or other film layer, such as a silicon oxide film layer or other film layer with passivation function. At least a portion of the dielectric layer 6 has a tunneling function, thereby achieving a composite contact between the first doped layer 2 and the second doped layer 4. In this way, the dielectric layer 6 can achieve a good passivation of the contact surface of the two while realizing the composite contact between them.

[0064] In some embodiments, a tunneling layer (not shown) may be provided between the first doped layer 2 and the back surface of the silicon wafer 1, and between the second doped layer 4 and the back surface of the silicon wafer 1. For example, the tunneling layer may be a film layer with passivation and tunneling functions, such as a silicon oxide tunneling layer. The specific type can be selected according to the actual situation, and no specific limitation is made here.

[0065] In some embodiments, a passivation layer (not shown) is further disposed on the first doped layer 2, the second doped layer 4, and the isolation region 13. The first electrode 3 located in the first region 11 passes through the passivation layer and contacts the first doped layer 2, and the second electrode 5 located in the second region 12 passes through the passivation layer and contacts the second doped layer 4. The passivation layer is preferably one or more combinations of an oxide layer, a silicon carbide layer, and an amorphous silicon layer. As some examples of this invention, the passivation layer can be an oxide layer of a single material, a combination of oxide layers of multiple materials and amorphous silicon layers, or a combination of multiple layers of amorphous silicon with different refractive indices of a single material. Furthermore, the passivation layer can also be a silicon oxynitride layer, a silicon nitride layer, etc. It is understood that the specific structural arrangement of the passivation layer includes, but is not limited to, the several methods listed above. The passivation layer is configured according to actual usage needs and is not specifically limited here.

[0066] In another embodiment of this utility model, the leakage contact 41 is in direct contact with the first doped layer 2.

[0067] In this embodiment, the leakage contact portion 41 of the second doped layer 4 forms a leakage contact with the first doped layer 2. Specifically, the leakage contact portion 41 of the second doped layer 4 and the first doped layer 2 can directly contact each other to form a composite contact; that is, there may be no insulation between the first doped layer 2 and the second doped layer 4, and the leakage contact portion 41 directly contacts the first doped layer 2 to form a composite contact.

[0068] This invention also provides a battery assembly including the back-contact solar cell described in the above embodiments. It should be noted that this battery assembly has the same or similar beneficial effects as the back-contact solar cell, and the related aspects between the two can be referred to each other; to avoid repetition, they will not be repeated here.

[0069] In this embodiment, multiple back-contact solar cells in the battery module can be connected in series to form a battery string, thereby achieving series current output. For example, the battery cells can be connected in series by setting solder strips (busbars, interconnecting strips), conductive backplates, etc.

[0070] It is understood that in such embodiments, the battery assembly may also include a metal frame, a backsheet, photovoltaic glass, and an encapsulating film. The encapsulating film may be filled between the front and back of the back-contact solar cell, the photovoltaic glass, adjacent cells, etc. As a filler, it may be a transparent colloid with good light transmittance and aging resistance. For example, the encapsulating film may be an EVA film or a POE film, and the specific choice can be made according to the actual situation, without limitation.

[0071] Photovoltaic glass can be applied to the encapsulating film on the front side of the back-contact solar cell. This photovoltaic glass can be ultra-clear glass, possessing high light transmittance, high transparency, and superior physical, mechanical, and optical properties. For example, ultra-clear glass can achieve a light transmittance of over 92%. It can protect the back-contact solar cell while minimizing impact on its efficiency. Simultaneously, the encapsulating film bonds the photovoltaic glass and the back-contact solar cell together, providing sealing, insulation, and waterproofing / moisture protection for the back-contact solar cell.

[0072] The backsheet can be attached to the adhesive film on the back of the back-contact solar cell. The backsheet protects and supports the solar cell, providing reliable insulation, water resistance, and aging resistance. Multiple backsheet options are available, typically including tempered glass, acrylic glass, and aluminum alloy TPT composite adhesive film, etc. The specific choice depends on the specific circumstances and is not limited here. The backsheet, back-contact solar cell, adhesive film, and photovoltaic glass can be mounted on a metal frame. The metal frame serves as the main external support structure for the entire back-contact solar cell module, providing stable support and installation. For example, the back-contact solar cell module can be installed at the desired location using the metal frame.

[0073] This invention also provides a photovoltaic system, which includes the battery module described in the above embodiments. It should be noted that this photovoltaic system has the same or similar beneficial effects as the back-contact solar cell described above, and the related aspects between the two can be referred to each other; to avoid repetition, they will not be repeated here.

[0074] In this embodiment, the photovoltaic system can be applied in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants. It can also be applied to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it is understood that the application scenarios of the photovoltaic system are not limited to these; that is, the photovoltaic system can be applied in all fields that require solar energy to generate electricity. Taking a photovoltaic power generation system grid as an example, the photovoltaic system may include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array may be an array combination of multiple back-contact solar cell modules. For example, multiple back-contact solar cell modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the combiner box, which can collect the current generated by the photovoltaic array. The collected current flows through the inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to achieve solar power supply.

[0075] In the description of this specification, references to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0076] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A back contact solar cell, characterized by, include: A silicon wafer, the back side of which includes a first region and a second region alternately spaced along a first direction; A first doped layer is disposed in the first region; A first electrode is disposed on the first doped layer, and the first electrode is connected to the first doped layer; A second doped layer is provided in the second region, wherein the doping polarity of the first doped layer and the second doped layer is opposite; and A second electrode is disposed on the second doped layer, and the second electrode is connected to the second doped layer; Wherein, at least a portion of the second doped layer has a leakage contact extending onto the first doped layer; the first doped layer includes a first sub-doped layer that forms a composite contact with the leakage contact and a second sub-doped layer that does not form a composite contact with the leakage contact, and at least one of the widths of the first sub-doped layer along the first direction is greater than the width of the second sub-doped layer along the first direction.

2. The back-contact solar cell according to claim 1, characterized in that, The width of any one of the first sub-doped layers along the first direction is greater than the width of the second sub-doped layer along the first direction.

3. The back contact solar cell of claim 1, wherein, Also includes: An isolation region is disposed between the first region and the second region, wherein the leakage contact portion of the second doped layer extends toward the isolation region and extends onto the first sub-doped layer.

4. The back contact solar cell of claim 1, wherein, The ratio of the width of the first sub-doped layer along the first direction to the width of the second sub-doped layer along the first direction is 1.1 to 2.

5.

5. The back contact solar cell of claim 4, wherein, The ratio of the width of the first sub-doped layer along the first direction to the width of the second sub-doped layer along the first direction is 1.4 to 1.

6.

6. The back contact solar cell of claim 1, wherein, The width of the first sub-doped layer along the first direction is 165 to 750 micrometers.

7. The back contact solar cell of claim 1 wherein, The width of the second sub-doped layer along the first direction is 150 to 300 micrometers.

8. The back contact solar cell of claim 1 wherein, The distance between the first electrode on the first sub-doped layer and the leakage contact portion along the first direction is 30 to 100 micrometers.

9. The back-contact solar cell according to claim 8, characterized in that, The distance between the first electrode on the first sub-doped layer and the leakage contact portion along the first direction is 50 to 60 micrometers.

10. The back-contact solar cell according to claim 1, characterized in that, A dielectric layer is disposed between the leakage contact portion of the second doped layer and the first doped layer, and the leakage contact portion of the second doped layer forms a composite contact with the first doped layer through the dielectric layer; or, the leakage contact portion of the second doped layer directly contacts the first doped layer to form a composite contact.

11. A battery assembly, characterized in that, Including the back-contact solar cell as described in any one of claims 1 to 10.

12. A photovoltaic system, characterized in that, Includes the battery assembly as described in claim 11.

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