Solar cell, cell module and photovoltaic system

Abstract

The utility model is suitable for the photovoltaic technology field, and provides a solar cell, a cell assembly and a photovoltaic system, the solar cell comprises a silicon substrate, the silicon substrate is provided with a light facing surface and a backlight surface which are oppositely arranged, and the backlight surface is alternately provided with a first area and a second area, the distance from the first region to the light-facing surface is greater than that from the second region to the light-facing surface; the first polarity doping layer is arranged in the first region; the second polarity doping layer is arranged in the second region, and the polarity of the second polarity doping layer is different from that of the first polarity doping layer; the groove is formed in the edge position, close to the first polarity doping layer, of the second polarity doping layer and divides the second polarity doping layer into a first part and a second part which are not communicated with each other. Large-area irradiation of large light spots on the joint area is avoided, so that laser damage to the first polarity doping layer is remarkably reduced, the position of the second polarity doping layer is low-lying, damage of subsequent procedures is reduced, and the isolation effect and the passivation performance are improved.

Description

Technical Field

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

[0002] In the research and manufacturing of solar cells, the proper design of trenches is crucial for improving cell performance. By incorporating trenches into the cell structure, doped regions of different polarities can be effectively isolated, reducing carrier recombination and optimizing carrier transport paths, thereby improving the cell's photoelectric conversion efficiency.

[0003] Traditional trench configurations, where trenches are placed at the junction of the first and second polarity doped layers, often require large-spot lasers for laser etching due to the irregular shape of this region. This large-spot laser irradiates a large area of ​​the junction, causing severe laser damage to the first polarity doped layer. This damage disrupts the structure of the semiconductor material, reduces carrier lifetime and mobility, and ultimately leads to decreased photoelectric conversion efficiency and reduced stability of the solar cell. Therefore, a new technical solution is urgently needed to address these issues and improve the performance and quality of solar cells. Utility Model Content

[0004] This invention provides a solar cell, a battery module, and a photovoltaic system, aiming to solve the problem of laser damage to the first polar doped layer.

[0005] This invention is implemented as follows: a solar cell includes:

[0006] A silicon substrate having a light-facing surface and a back-light surface disposed opposite to each other, wherein a first region and a second region are alternately disposed on the back-light surface, and the distance from the first region to the light-facing surface is greater than the distance from the second region to the light-facing surface;

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

[0008] A second polar doped layer is disposed in the second region, the polarities of the second polar doped layer and the first polar doped layer being opposite; and,

[0009] The trench is disposed at the edge of the second polar doped layer near the first polar doped layer, dividing the second polar doped layer into a first part and a second part that are not connected.

[0010] Optionally, the width of the trench is 100~120μm.

[0011] Optionally, the horizontal distance from the edge of the trench near the first polar doped layer to the first polar doped layer is 30~90μm.

[0012] Optionally, the sidewall height of the trench near the first polar doped layer is equal to the sidewall height of the trench away from the first polar doped layer.

[0013] Optionally, the first portion is close to the first region, the first portion extends to cover the sidewall between the first region and the second region, and has an extension that extends over the first polar doped layer.

[0014] Optionally, an insulating layer is provided between the first polar doped layer and the extension in the first region.

[0015] Optionally, the solar cell further includes:

[0016] A first tunneling layer is disposed between the first polar doped layer and the silicon substrate;

[0017] The second tunneling layer is disposed between the second polar doped layer and the silicon substrate.

[0018] Optionally, the trench penetrates the second tunneling layer.

[0019] Optionally, it further includes a second electrode, which is in ohmic contact with the second polar doped layer, and the trench is disposed between the second electrode and the first region.

[0020] This utility model also provides a battery assembly, including the aforementioned solar cell.

[0021] This utility model also provides a photovoltaic system, including the above-mentioned battery components.

[0022] The beneficial effects achieved by this invention are as follows: Because the trench is positioned at the edge of the second polar doped layer near the first polar doped layer, the laser primarily acts on the area near the pn junction of the second polar doped layer. This means the laser acts directly on the second polar doped layer, eliminating the need to consider the irregular shape of the junction. A small laser spot can be used, avoiding large-area irradiation of the junction region by a large laser spot. This significantly reduces laser damage to the first polar doped layer. Furthermore, the low-lying location of the second polar doped layer reduces damage from subsequent processes, improving isolation and passivation performance. Ultimately, this enhances the photoelectric conversion efficiency and stability of the battery. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the first structure of the solar cell provided by this utility model;

[0024] Figure 2 This is a schematic diagram of the second structure of the solar cell provided by this utility model.

[0025] Explanation of reference numerals in the attached figures:

[0026] 100, Solar cell; 101, First region; 102, Second region; 110, First polar doped layer; 120, Second polar doped layer; 121, First part; 122, Second part; 123, Extension; 130, Trench; 140, First tunneling layer; 150, Second tunneling layer; 160, First electrode; 170, Second electrode; 180, Insulating layer; 190, Silicon substrate. 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 the 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 this utility model, and should not be construed as limiting this utility model. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this utility model and are not intended to limit this utility model.

[0028] In the description of this utility model, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying 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] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0030] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0031] 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.

[0032] 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, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0033] This invention places the trench at the edge of the second polar doped layer near the first polar doped layer. The laser primarily acts on the second polar doped layer near the pn junction, meaning the laser acts directly on the second polar doped layer. This eliminates the need to consider the irregular shape of the junction between the first and second polar doped layers, allowing the use of a small laser spot. This avoids large-area irradiation of the junction region by a large laser spot, significantly reducing laser damage to the first polar doped layer. Furthermore, the low-lying location of the second polar doped layer reduces damage from subsequent processes, improving isolation and passivation performance. Ultimately, this enhances the photoelectric conversion efficiency and stability of the battery.

[0034] Example One

[0035] like Figure 1 and Figure 2 As shown, this embodiment provides a solar cell 100, including:

[0036] The silicon substrate 190 has a light-facing surface and a back-light-facing surface disposed opposite to each other. A first region 101 and a second region 102 are alternately disposed on the back-light-facing surface. The distance from the first region 101 to the light-facing surface is greater than the distance from the second region 102 to the light-facing surface.

[0037] A first polar doped layer 110 is disposed in the first region 101;

[0038] A second polar doped layer 120 is disposed in the second region 102, and the polarities of the second polar doped layer 120 and the first polar doped layer 110 are opposite; and,

[0039] The trench 130 is disposed at the edge of the second polar doped layer 120 near the first polar doped layer 110, dividing the second polar doped layer 120 into a first part 121 and a second part 122 that are not connected.

[0040] The silicon substrate 190 has two main surfaces: a light-facing surface and a back-lighting surface. The light-facing surface directly faces the sunlight, while the back-lighting surface is on the opposite side. The two surfaces are positioned opposite each other.

[0041] Two distinct regions, a first region 101 and a second region 102, are arranged alternately on the backlight surface of the silicon substrate 190. Specifically, a plurality of first regions 101 and a plurality of second regions 102 are arranged alternately along a first direction, and both the first regions 101 and the second regions 102 extend along a second direction, which intersects the first direction. The first regions 101 and the second regions 102 can be arranged alternately along the lateral direction of the silicon substrate 190 and both extend along the longitudinal direction; that is, the first direction can be the lateral direction of the back contact battery, and the second direction can be the longitudinal direction of the back contact battery, and the two are perpendicular to each other. Of course, in other embodiments, the first direction and the second direction can also be other directions, for example, they can be the diagonal directions of the silicon substrate 190, and no specific limitation is made here. The first regions 101 and the second regions 102 do not overlap and are arranged adjacent to each other.

[0042] A first polar doped layer 110 is disposed in the first region 101, and a second polar doped layer 120 is disposed in the second region 102. The first polar doped layer 110 and the second polar doped layer 120 have opposite polarities. Specifically, the first polar doped layer 110 can be a P-type doped layer and the second polar doped layer 120 can be an N-type doped layer, or the first polar doped layer 110 can be an N-type doped layer and the second polar doped layer 120 can be a P-type doped layer. The first polar doped layer 110 and the second polar doped layer 120 form regions with different electrical characteristics, supporting the formation of a PN junction and the separation of charge carriers.

[0043] The trench 130 is located near the edge of the second polar doped layer 120, close to the edge of the first polar doped layer 110. The trench 130 serves as a physical isolation layer, reducing direct diffusion and recombination of charge carriers between pn regions. The second polar doped layer 120 has a certain width. As can be understood, an object with width has a center position and edges; the center position is the position equidistant from the opposite two edges. When a preset position is placed between the center position and the edge, if the distance from the preset position to the edge is less than the distance to the center position, the preset position is closer to the edge; if the distance from the preset position to the edge is greater than the distance to the center position, the preset position is closer to the center position.

[0044] The second polar doped layer 120 is divided into a first part 121 and a second part 122 that are not connected. That is, the trench 130 penetrates through the second polar doped layer 120, isolating it. The main function of the trench 130 is to reduce leakage between different polar doped layers, avoid abnormal recombination and leakage of some charge carriers between different polar doped layers, improve the open circuit voltage and fill factor of the battery, and thus improve the photoelectric conversion efficiency of the battery.

[0045] In semiconductor devices such as solar cells, the pn junction formed by the p-type doped region (p-region) and the n-type doped region (n-region) is a key structure for achieving photoelectric conversion and other functions. However, due to limitations in manufacturing processes, the pn junction is not an ideally straight line. In actual production, factors such as the inhomogeneity of the impurity diffusion process and errors in the photolithography process can cause the pn junction to exhibit an irregular shape, which may be curved, undulating, or have local jagged edges. Typically, trenches 130 are placed between the p-region and the n-region. To ensure that the irregular pn junction can be fully laser-irradiated and achieve effective pn region isolation, a large laser spot is often required. A large spot covers a larger area of ​​the p-region, and excessive laser energy acting on the p-region can damage the semiconductor material structure, introducing more crystal defects. These defects become centers for carrier recombination, reducing carrier lifetime and mobility, thus affecting the photoelectric conversion efficiency and other performance indicators of the cell.

[0046] The distance from the first region 101 to the light-facing surface is greater than the distance from the second region 102 to the light-facing surface. This means the second polar doped layer 120 in the second region 102 is lower than the first polar doped layer 110 in the first region 101, creating a relatively low-lying area. On one hand, placing the trench 130 in this low-lying area of ​​the second polar doped layer 120 reduces damage from subsequent processes. In subsequent processes, operations such as chemical solution rinsing and mechanical contact can cause direct physical damage to the trench. By placing the trench 130 in the relatively lower second polar doped layer 120, its low-lying location provides a protective barrier, greatly reducing the impact of external factors on the trench 130 and thus ensuring the isolation effect.

[0047] On the other hand, due to the relatively concealed location, the passivation material is more likely to form a continuous and dense film layer inside and around the trench 130 during the passivation process, thereby effectively reducing the surface state density and improving the passivation effect. The low-lying location can also reduce the introduction of external impurities and defects, further improving the passivation quality and providing a good environment for the efficient transport of charge carriers.

[0048] It is understandable that the first region 101 and the second region 102 are alternately set, and the first polar doped layer 110 and the second polar doped layer 120 are also alternately set accordingly. When the first region 101 is set on both sides of the second region 102, the first polar doped layer 110 is also set on both sides of the corresponding second polar doped layer 120. Trench 130 is set on both sides of the second polar doped layer 120 near the edge of the first polar doped layer 110.

[0049] In this application, the trench 130 is positioned at the edge of the second polar doped layer 120 near the first polar doped layer 110. The laser primarily acts on the second polar doped layer 120 near the pn junction, meaning the laser acts directly on the second polar doped layer 120. This eliminates the need to consider the irregular shape at the junction of the first and second polar doped layers 110, allowing for the use of a small laser spot. This avoids large-area irradiation of the first polar doped layer 110 by a large laser spot, significantly reducing laser damage to the first polar doped layer 110. Furthermore, the low-lying position of the second polar doped layer 120 reduces damage from subsequent processes, improving isolation and passivation performance. Ultimately, this enhances the photoelectric conversion efficiency and stability of the battery.

[0050] Example Two

[0051] In some embodiments, the width of the groove 130 is 100~120μm.

[0052] When the trench 130 is positioned between the first region 101 and the second region 102, the trench 130 is relatively wide, typically 150-200 μm or even wider, due to the removal of the irregular edges of the first polar doped layer 110. Because more material needs to be removed, the laser energy acts over a larger area, causing severe damage to the crystal structure of the surrounding first polar doped layer 110 and second polar doped layer 120.

[0053] A suitable trench width 130 can ensure effective isolation between the first portion 121 and the second portion 122 of the second polarity doped layer 120 while avoiding excessive cell area occupation due to excessive width, thus affecting the cell's photoelectric conversion efficiency. A width range of 100–120 μm has been proven in practice to effectively balance isolation effect and cell area utilization efficiency. For example, when the trench width 130 is 100 μm, leakage between different polarity doped layers is significantly reduced, and the cell's open-circuit voltage and fill factor are significantly improved.

[0054] Example Three

[0055] In some embodiments, the horizontal distance from the edge of the trench 130 near the first polar doped layer 110 to the first polar doped layer 110 is 30~90μm.

[0056] The trench 130 has two opposing edges. The edge that is closer to the first polar doped layer 110 in terms of horizontal distance is the edge closer to the first polar doped layer 110, and the edge that is farther away from the first polar doped layer 110 in terms of horizontal distance is the edge farther away from the first polar doped layer 110.

[0057] Understandably, the sidewalls of the trench 130 may have a certain slope or curvature, and the edge of the trench 130 in this application refers to the edge of the groove opening.

[0058] The trench 130 divides the second polar doped layer 120 into a first portion 121 and a second portion 122. Assuming the portion closest to the first polar doped layer 110 is the first portion 121 (or the second portion 122), that is, the first portion 121 (or the second portion 122) is blocked by the trench 130. Typically, a first electrode 160 is disposed on the first polar doped layer to collect the charge carriers generated by the first polar doped layer 110, and a second electrode 170 is disposed on the second polar doped layer 120 to collect the charge carriers generated by the second polar doped layer 120. To ensure uniform collection, the electrodes are positioned in the middle of their respective doped layers. Due to the obstruction of the trench 130, the charge carriers generated in the first portion 121 cannot be transported to the second electrode 170 and cannot be collected and utilized.

[0059] The horizontal distance from the edge of trench 130 to the first polar doped layer 110 is the distance between the projection of the edge of trench 130 onto the light-facing surface and the projection of the edge of the first polar doped layer 110 onto the light-facing surface. When the horizontal distance from the edge of trench 130 to the first polar doped layer 110 is less than 30 μm, laser operation is inconvenient and it is easy to cause misoperation of the first polar doped layer 110. When the horizontal distance from the edge of trench 130 to the first polar doped layer 110 is greater than 90 μm, the area of ​​the first part 121 is too large, resulting in a waste of charge carriers.

[0060] In this embodiment, the horizontal distance from the edge of the trench 130 near the first polar doped layer 110 to the first polar doped layer 110 is 30~90μm, which facilitates processing and avoids the waste of charge carriers.

[0061] In some embodiments, a second electrode 170 is further included, the second electrode 170 being in ohmic contact with the second polar doped layer 120, and a trench 130 is disposed between the second electrode 170 and the first region 101.

[0062] That is, the second electrode 170 is located in the middle of the second polar doped layer 120. The middle part of the second polar doped layer 120 is flat and has a relatively large area. In other words, the trench 130 divides the second polar doped layer 120 into a first part 121 and a second part 122. Assuming that the part closer to the first polar doped layer 110 is the first part 121, the area of ​​the second part 122 is larger than the area of ​​the first part 121. Specifically, the area of ​​the second part 122 is more than twice the area of ​​the first part 121. The second electrode 170 is located in the middle, that is, in the second part 122. A larger area results in more charge carriers being generated. The second electrode 170 is used to collect the charge carriers generated in the second part 122.

[0063] Example Four

[0064] In some embodiments, the sidewall height of the trench 130 near the first polar doped layer 110 is equal to the sidewall height of the trench 130 away from the first polar doped layer 110.

[0065] The surface of the second region 102 can be polished or velvety, but macroscopically, the surface of the second region 102 is flat or roughly flat, that is, the distance from the surface of the second region 102 to the light-facing surface is roughly equal.

[0066] A second polar doped layer 120 is disposed on the second region 102, and a trench 130 is disposed on the second polar doped layer 120. The two side walls of the trench 130 have equal heights, meaning that the distances from the first portion 121 and the second portion 122 on both sides of the trench 130 to the light-facing surface are approximately the same. Specifically, the second polar doped layer 120 on both sides of the trench 130 may have equal thicknesses, or other functional layers may be stacked on the second region 102, with each functional layer having an equal thickness.

[0067] In this embodiment, the sidewall height of the trench 130 near the first polar doped layer 110 is equal to the sidewall height of the trench 130 away from the first polar doped layer 110. This structure makes it easier to achieve process stability and repeatability during manufacturing. Isotropic etching technology is relatively mature and can ensure the consistency of the sidewall height of the trench 130 in batteries produced in different batches, thereby improving the product yield.

[0068] Example Five

[0069] like Figure 2 As shown, in some embodiments, the first portion 121 is close to the first region 101, the first portion 121 extends to cover the sidewall between the first region 101 and the second region 102, and has an extension 123 extending over the first polar doped layer 110.

[0070] In preparing the first portion 121 of the second polar doped layer 120, a vapor deposition process is employed, so that the first portion 121 not only covers the second region 102, but also extends to cover the sidewall between the first region 101 and the second region 102, and has an extension 123 extending above the first polar doped layer 110. By controlling parameters such as the flow rate, temperature, and time of the deposition gas, the growth and coverage range of the extension 123 are precisely controlled.

[0071] The extension 123 extending over the first polar doped layer 110 can improve the interface performance between the two doped layers, reduce carrier recombination at the interface, and improve the photoelectric conversion efficiency of the battery.

[0072] In some embodiments, an insulating layer 180 is provided between the first polar doped layer 110 and the extension 123 within the first region 101.

[0073] The insulating layer 180 effectively isolates the first polar doped layer 110 and the extension 123, preventing short circuits between doped layers of different polarities and improving the safety and stability of the battery. Simultaneously, the insulating layer 180 reduces carrier recombination at the interface between the two doped layers, improving carrier collection efficiency.

[0074] Example Six

[0075] In some embodiments, the solar cell 100 further includes:

[0076] The first tunneling layer 140 is disposed between the first polar doped layer 110 and the silicon substrate 190;

[0077] The second tunneling layer 150 is disposed between the second polar doped layer 120 and the silicon substrate 190.

[0078] The tunneling layer provides quantum tunneling, making it easier for photogenerated carriers to transport from the silicon substrate to the corresponding doped layer, reducing energy loss at the interface and improving the photoelectric conversion efficiency of the battery. Experiments have shown that, under the same illumination conditions, batteries with tunneling layers can output higher currents than those without.

[0079] The first tunneling layer 140 and the second tunneling layer 150 can respectively improve the interface passivation performance between the first polar doped layer 110 and the second polar doped layer 120 and the silicon substrate 190, reduce the interface state density, reduce the recombination rate of charge carriers, thereby improving the open circuit voltage and fill factor of the battery.

[0080] In some embodiments, the trench 130 penetrates the second tunnel layer 150.

[0081] The tunneling layer is a conductive layer. The trench 130 penetrates the second tunneling layer 150, which can further enhance the isolation of the regions on both sides of the trench 130, prevent the regions on both sides of the trench 130 from being connected through the second tunneling layer 150, and prevent the charge carriers from spreading laterally through the second tunneling layer 150.

[0082] Example Eight

[0083] This embodiment provides a battery assembly, including the solar cell 100 described above.

[0084] The battery module may include multiple solar cells 100. The multiple solar cells 100 in the battery module can be connected in series to form a battery string. The battery strings can be connected in series, in parallel, or in a series-parallel combination to achieve current charging output. For example, the connection between the individual cells can be achieved by welding the welding strips, or the connection between the individual battery strings can be achieved by busbars.

[0085] The battery module may also include a metal frame, a backsheet, photovoltaic glass, and an encapsulating film (not shown in the figures). The encapsulating film can be filled between the light-facing side of the solar cell 100 and the photovoltaic glass, the back-facing side and the backsheet, and adjacent cells. As a filler, it can be a transparent colloid with good light transmittance and aging resistance. For example, the encapsulating film can be EVA film or POE film, and the specific choice can be made according to the actual situation. There are no restrictions here.

[0086] Photovoltaic glass can be applied to the encapsulating film on the light-facing side of the solar cell 100. 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%, protecting the solar cell 100 while minimizing impact on its efficiency. Simultaneously, the encapsulating film bonds the photovoltaic glass and the solar cell 100 together, providing sealing, insulation, and waterproofing / moisture protection for the solar cell 100.

[0087] The backsheet can be attached to the film on the back side of the solar cell 100. The backsheet protects and supports the solar cell 100, providing reliable insulation, water resistance, and aging resistance. Multiple backsheet options are available, typically including tempered glass, acrylic glass, and aluminum alloy TPT composite film, etc. The specific choice depends on the specific circumstances and is not limited here. The backsheet, solar cell 100, film, and photovoltaic glass can be mounted on a metal frame. The metal frame serves as the main external support structure for the entire battery module, providing stable support and installation. For example, the battery module can be installed at the desired location using the metal frame.

[0088] The beneficial effects of the battery module in this embodiment are equivalent to those of the solar cell 100 described above, and will not be repeated here.

[0089] Example Nine

[0090] This embodiment provides a photovoltaic system, including the aforementioned battery module.

[0091] Photovoltaic systems can be applied in photovoltaic power plants, such as ground-mounted, rooftop, and floating power plants, as well as in 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's understandable that the application scenarios of photovoltaic systems are not limited to these; that is, photovoltaic systems can be applied in all fields that require solar energy to generate electricity. Taking a photovoltaic power generation network as an example, a photovoltaic system can include photovoltaic arrays, combiner boxes, and inverters. A photovoltaic array can be a combination of multiple battery modules; for example, multiple battery modules can form multiple photovoltaic arrays. The photovoltaic arrays are connected to combiner boxes, which collect the current generated by the photovoltaic arrays. The collected current flows through an inverter and is converted into AC power required by the mains grid before being connected to the mains grid to achieve solar power supply.

[0092] The beneficial effects of the photovoltaic system in this embodiment are equivalent to the beneficial effects of the battery module described above, and will not be repeated here.

[0093] 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 solar cell, characterized in that, include: A silicon substrate having a light-facing surface and a back-light surface disposed opposite to each other, wherein a first region and a second region are alternately disposed on the back-light surface, and the distance from the first region to the light-facing surface is greater than the distance from the second region to the light-facing surface; A first polar doped layer is disposed in the first region; A second polar doped layer is disposed in the second region, and the polarities of the second polar doped layer and the first polar doped layer are opposite. as well as, The trench is disposed at the edge of the second polar doped layer near the first polar doped layer, dividing the second polar doped layer into a first part and a second part that are not connected.

2. The solar cell as described in claim 1, characterized in that, The width of the groove is 100~120μm.

3. The solar cell as described in claim 1, characterized in that, The horizontal distance from the edge of the trench near the first polar doped layer to the first polar doped layer is 30~90μm.

4. The solar cell as described in claim 1, characterized in that, The height of the sidewall of the trench near the first polar doped layer is equal to the height of the sidewall of the trench away from the first polar doped layer.

5. The solar cell as described in claim 1, characterized in that, The first portion is close to the first region, the first portion extends to cover the sidewall between the first region and the second region, and has an extension that extends over the first polar doped layer.

6. The solar cell as described in claim 5, characterized in that, An insulating layer is disposed between the first polar doped layer and the extension in the first region.

7. The solar cell as described in claim 1, characterized in that, The solar cell also includes: A first tunneling layer is disposed between the first polar doped layer and the silicon substrate; The second tunneling layer is disposed between the second polar doped layer and the silicon substrate.

8. The solar cell as described in claim 7, characterized in that, The trench penetrates the second tunnel layer.

9. The solar cell as described in claim 1, characterized in that, It also includes a second electrode, which is in ohmic contact with the second polar doped layer, and the trench is disposed between the second electrode and the first region.

10. A battery assembly, characterized in that, Includes the solar cell described in any one of claims 1-9.

11. A photovoltaic system, characterized in that, Includes the battery assembly as described in claim 10.

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