Solar cell, cell module and photovoltaic system

Abstract

The invention is suitable for the technical field of solar cells, and provides a solar cell. The solar cell comprises a silicon substrate and a fine grid, the silicon substrate comprises a plurality of P-type regions and a plurality of N-type regions which are arranged at intervals along a first direction, the plurality of P-type regions and the plurality of N-type regions extend along a second direction, and the second direction is crossed with the first direction; the fine grids comprise first fine grids arranged in the P-type region and second fine grids arranged in the N-type region, and the average height of at least one first fine grid is larger than that of at least one second fine grid. As the cross-sectional area of the fine grid is in direct proportion to the height, the cross-sectional area is increased by increasing the height of the first fine grid in the P-type region, and the cross-sectional area is increased and the resistance is reduced according to the resistance law, so that carriers can flow more smoothly, and the current enrichment capability of the P-type region is enhanced.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar cells, and in particular relates to a solar cell, a cell assembly and a photovoltaic system. Background Art

[0002] In today's context of growing energy demand and increasing environmental awareness, solar cells, as an important clean energy conversion device, have attracted widespread attention. Traditional solar cells have some limitations in their structural design, which affect their photoelectric conversion efficiency and performance stability.

[0003] In traditional solar cells, the silicon substrate contains P-type and N-type regions for generating holes and electrons, while a fine gate collects these conduction carriers. Due to the different physical properties of the P-type and N-type regions, the current collection in the P-type and N-type regions is mismatched, resulting in low current collection efficiency and photoelectric conversion efficiency. Poor carrier transport can also cause localized heating, affecting the stability and lifespan of the cell. Therefore, innovative designs are urgently needed to address these issues, improve the matching of current enrichment capabilities between regions, ensure smooth carrier flow, and enhance the overall performance of solar cells. This is of great significance to the development of the photovoltaic industry. Summary of the Invention

[0004] The present invention provides a solar cell, a cell assembly and a photovoltaic system, aiming to solve the problem of low photoelectric conversion efficiency caused by current enrichment mismatch between P-type and N-type regions.

[0005] The present invention is implemented as follows: a solar cell comprises: a silicon substrate and a fine grid;

[0006] The silicon substrate includes a plurality of P-type regions and a plurality of N-type regions spaced apart along a first direction, wherein the plurality of P-type regions and the plurality of N-type regions extend along a second direction, and the second direction intersects the first direction;

[0007] The fine gates extend along the second direction and include a first fine gate disposed in the P-type region and a second fine gate disposed in the N-type region. The average height of at least one of the first fine gates is greater than the average height of at least one of the second fine gates.

[0008] Optionally, a first main grid is further included, wherein the first main grid is connected to a plurality of the first fine grids, and the height of the first fine grid decreases along the second direction as the distance from the first main grid increases, and the height of the first fine grid is the largest at the connection position with the first main grid.

[0009] Optionally, a first main gate is further included, wherein the first main gate is connected to several of the first fine gates, and the width of the first fine gate decreases along the second direction as the distance between the first fine gate and the first main gate increases. The first fine gate has the largest width at the connection position with the first main gate.

[0010] Optionally, a second main gate is further included, which is connected to several second fine gates. The height of the second fine gate decreases along the second direction as the distance between the second fine gate and the second main gate increases. The height of the second fine gate is the largest at the connection position with the second main gate.

[0011] Optionally, a second main gate is further included, which is connected to several second fine gates. The width of the first fine gate decreases along the second direction as the distance between the first fine gate and the first main gate increases. The first fine gate has the largest width at the connection position with the first main gate.

[0012] Optionally, an average height-to-width ratio of at least one of the first fine grids is greater than an average height-to-width ratio of at least one of the second fine grids.

[0013] Optionally, at a position where the first fine gate is connected to the first main gate, a height of the first fine gate is greater than or equal to a height of the first main gate.

[0014] Optionally, at a position where the second fine gate is connected to the second main gate, a height of the second fine gate is greater than or equal to a height of the second main gate.

[0015] Optionally, the aspect ratio of the first fine gate at the same distance from the main gate is greater than the aspect ratio of the second fine gate.

[0016] Optionally, the aspect ratio of the first fine gate and the second fine gate is in a range of 0.15 to 0.35.

[0017] The present invention also provides a battery assembly comprising the above-mentioned solar cell.

[0018] The present invention also provides a photovoltaic system comprising the above-mentioned battery assembly.

[0019] The beneficial effects achieved by the present invention are achieved by designing a silicon substrate and fine gates. The silicon substrate includes a plurality of P-type regions and a plurality of N-type regions spaced apart along a first direction and extending along a second direction intersecting the first direction. The fine gates include a first fine gate located within the P-type region and a second fine gate located within the N-type region. The average height of at least one first fine gate is greater than the average height of at least one second fine gate. Because the cross-sectional area of a fine gate is proportional to its height, increasing the height of the first fine gate in the P-type region increases its cross-sectional area. According to the resistance law, increasing the cross-sectional area reduces the resistance, thereby achieving smoother carrier flow and enhancing the current enrichment capability of the P-type region. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 1 is a schematic diagram of the top view of the solar cell provided by the present invention;

[0021] Figure 2 This is a schematic diagram of the AA-direction structure of a solar cell provided by the invention;

[0022] Figure 3 This is a schematic diagram of the AA-direction structure of a solar cell provided by the invention;

[0023] Figure 4 It is a schematic diagram of the AA-oriented structure of a solar cell provided by the invention.

[0024] Description of reference numerals:

[0025] 100 , solar cell; 110 , silicon substrate; 111 , P-type region; 112 , N-type region; 120 , first fine gate; 130 , second fine gate; 140 , first main gate; 150 , second main gate. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is 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 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 are not to 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.

[0027] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "left", "right", "horizontal", "top", "bottom", etc., indicating the orientation or position relationship, are based on the orientation or position relationship 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.

[0028] 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 the technical features being referred to. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0029] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections, or mutual communication; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0030] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0031] The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those skilled in the art will appreciate the application of other processes and / or the use of other materials.

[0032] The present invention employs a silicon substrate and fine gates. The silicon substrate comprises a plurality of P-type regions and a plurality of N-type regions spaced apart along a first direction and extending in a second direction intersecting the first direction. The fine gates include a first fine gate located within the P-type region and a second fine gate located within the N-type region. The average height of at least one of the first fine gates is greater than the average height of at least one of the second fine gates. Because the cross-sectional area of a fine gate is proportional to its height, increasing the height of the first fine gate in the P-type region increases its cross-sectional area. According to the resistance law, increasing the cross-sectional area reduces the resistance, thereby enabling smoother carrier flow and enhancing the current enrichment capability of the P-type region.

[0033] Example 1

[0034] like Figure 1 and Figure 2As shown, this embodiment provides a solar cell 100, comprising: a silicon substrate 110 and a fine grid;

[0035] The silicon substrate 110 includes a plurality of P-type regions 111 and a plurality of N-type regions 112 spaced apart along a first direction. The plurality of P-type regions 111 and the plurality of N-type regions 112 extend along a second direction, and the second direction intersects the first direction.

[0036] The fine gates extend along the second direction and include a first fine gate 120 disposed in the P-type region 111 and a second fine gate 130 disposed in the N-type region 112 . The average height of at least one first fine gate 120 is greater than the average height of at least one second fine gate 130 .

[0037] Silicon base 110 includes a silicon substrate and various functional layers stacked on the silicon substrate. Each functional layer includes a P-type doped layer and an N-type doped layer. The P-type doped layer is provided in a P-type region 111, and the N-type doped layer is provided in an N-type region 112. P-type region 111 and N-type region 112 form regions with different electrical characteristics, supporting the formation of a PN junction and the separation of carriers.

[0038] Several N-type regions 112 and several P-type regions 111 are alternately arranged along a first direction, and both the N-type regions 112 and the P-type regions 111 extend along a second direction that intersects the first direction. The N-type regions 112 and the P-type regions 111 can be alternately arranged along the lateral direction of the silicon substrate 110 and both extend along the longitudinal direction. That is, the first direction can be the lateral direction of the back-contact cell, and the second direction can be the longitudinal direction of the back-contact cell, with the two being perpendicular to each other. Of course, in other embodiments, the first direction and the second direction can also be other directions, for example, both can be diagonal directions of the silicon substrate 110, and this is not limited to this specific embodiment.

[0039] The fine gate contacts the doped layer and is used to collect carriers (electrons and holes) generated by the doped layer. The first fine gate 120 is disposed in the P-type region 111, extends along the second direction, contacts the P-type doped layer, and collects holes generated by the P-type doped layer. The second fine gate 130 is disposed in the N-type region 112, extends along the second direction, contacts the N-type doped layer, and collects electrons generated by the N-type doped layer.

[0040] It should be noted that in this embodiment, the "height" of the fine gate refers to the distance from the upper surface of the doped layer to the top of the fine gate. The fine gate usually penetrates into the doped layer, and the "height" of the fine gate does not include the length of the portion that penetrates into the doped layer.

[0041] It should also be noted that "average height" is a statistical value used to represent the overall height level of a particular grating along its length. Because the grating may not have an absolutely regular shape, its height along the second direction may fluctuate and vary to some extent, such as having protrusions, depressions, or slopes, which are not limited here.

[0042] Specifically, the "average height" can be obtained by the following method. Along the extension direction of the fine grid length, determine the number of points to be selected according to actual needs, and ensure that the distance between each point is equal. In order to ensure the accuracy of the data, the number of points selected is usually not less than 5. For example, for a fine grid with a length of 150μm, 11 measurement points can be selected, then the distance between adjacent points is 150÷(11-1)=15μm. Use a measuring tool (such as a 3D microscope) to measure the height of each determined point and accurately record the measurement results. Add up the height measurements of all points and divide it by the number of points to get the average height.

[0043] The "average height" can also be obtained by selecting a section of thin grid of a preset length at a preset distance from the main grid, measuring the height of each position on this section, adding the height measurements at each position, and then dividing by the number of positions to obtain the average height. It should be noted that the "preset distance" allows an error range of ±10μm. For example, the distance between the first thin grid and the first main grid is 70μm, and the distance between the second thin grid and the second main grid is 75μm. These can both be considered to be at the "preset distance" from the main grid.

[0044] In the solar cell 100, the doping concentration of the P-type region 111 is lower than the doping concentration of the N-type region 112. The lower doping concentration makes it relatively difficult for the P-type region 111 to enrich carriers (such as holes). Generally speaking, in order to ensure the aesthetics of the overall appearance of the solar cell 100, the width design difference between the first fine grid 120 and the second fine grid 130 is not much different. When the width is the same, according to geometric knowledge, the cross-sectional area of the fine grid is proportional to the height, that is, the greater the height, the larger the cross-sectional area. By increasing the height of the first fine grid 120 in the P-type region 111, the cross-sectional area of the first fine grid 120 is also increased. According to the resistance law, the cross-sectional area increases and the resistance decreases. Lower resistance is conducive to a smoother flow of carriers, thereby enhancing the current enrichment ability of the P-type region 111.

[0045] In this embodiment, the silicon substrate 110 and fine gates are designed so that the silicon substrate 110 includes a plurality of P-type regions 111 and a plurality of N-type regions 112 spaced apart along a first direction and extending along a second direction intersecting the first direction. The fine gates include a first fine gate 120 located within the P-type region 111 and a second fine gate 130 located within the N-type region 112. The average height of at least one first fine gate 120 is greater than the average height of at least one second fine gate 130. Because the cross-sectional area of a fine gate is proportional to its height, increasing the height of the first fine gate 120 in the P-type region 111 increases its cross-sectional area. According to the resistance law, increasing the cross-sectional area reduces the resistance, thereby enabling smoother carrier flow and enhancing the current enrichment capability of the P-type region 111.

[0046] Example 2

[0047] like Figure 3 As shown, in some embodiments, a first main gate 140 is further included, and the first main gate 140 is connected to several first fine gates 120. Along the second direction, the height of the first fine gate 120 at a position close to the first main gate 140 is greater than the height of the first fine gate 120 at a position far away from the first main gate.

[0048] The height of the first fine gate 120 near the connection between the first fine gate 120 and the first busbar 140 is greater than the height of the first fine gate 120 farther from the first busbar 140. Specifically, different locations on the same first fine gate 120 have different distances from the first busbar 140. For example, if two points on the first fine gate 120 are selected, the location with the shorter distance is near the connection between the first fine gate 120 and the first busbar 140, and the location with the longer distance is farther from the first busbar 140. For example, the height of a location on the first fine gate 120 that is 20 microns away from the first busbar 140 is greater than the height of at least one location on the first fine gate 120 that is farther from the first busbar 140 than 20 microns. Specifically, this may be any location farther from the first busbar 140 than 20 microns, such as a location 23 microns away from the first busbar 140, a location 40 microns away from the first busbar 140, or other locations.

[0049] The first fine gate 120 is taller near its connection with the first main gate 140, increasing its cross-sectional area and reducing its resistance. The first fine gate 120 collects carriers within the P-type region 111. The closer it is to the first main gate 140, the more carriers accumulate on the first fine gate 120, reducing its resistance and enabling smoother carrier transmission within the first fine gate 120. This reduces energy loss during current transmission and thus improves the photovoltaic cell's photoelectric conversion efficiency.

[0050] In some embodiments, the height of the first fine gate 120 decreases as the distance from the first main gate 140 increases, and the height of the first fine gate 120 is the highest at the connection position with the first main gate 140 .

[0051] In the solar cell 100, the primary function of the first fine grid 120 is to collect hole carriers generated by the P-type region 111, then transfer these carriers to the connected first main grid 140, and ultimately transmit the carriers outward through the first main grid 140. Since carriers converge toward the main grid from various locations on the fine grid, the closer the location is to the main grid, the greater the number of carriers that need to be transferred.

[0052] On the one hand, along the extension direction of the first fine grid 120, the greater the height of the first fine grid 120, the larger the cross-sectional area. Therefore, the first fine grid 120 is designed to be at its highest height at the connection point with the first main grid 140, and its height decreases as the distance from the first main grid 140 increases. This ensures that the fine grid has a lower resistance near the main grid, where the carrier flow is the largest. In this way, the resistance encountered by carriers during transmission is smaller, thereby reducing energy loss caused by resistance and improving the energy conversion efficiency of the battery.

[0053] On the other hand, if this decreasing height design is not adopted, the entire fine grid may need to be designed to be relatively high to ensure sufficient carrier transmission capacity. However, in reality, the number of carriers is relatively small at locations far from the main grid, and a fine grid that is too high will result in material waste. By designing the fine grid height to decrease as the distance from the main grid increases, the amount of fine grid material used is reduced while still meeting the carrier transmission requirements, thereby reducing the manufacturing cost of the solar cell 100.

[0054] Specifically, the height of the first fine grid 120 changes linearly, the entire change trend is gentle, and there is no protruding point, which reduces the possibility of tip discharge.

[0055] In this embodiment, the closer to the main grid, the more carriers there are, and the larger the fine grid height provides a larger carrier transmission channel. Just like a river, the river channel is wider where the water converges, allowing the water to flow more smoothly. Similarly, the larger cross-sectional area enables more efficient carrier transmission, avoiding congestion and accumulation of carriers during transmission, ensuring that carriers can be quickly and smoothly transmitted from the fine grid to the main grid, further improving the power generation efficiency of the battery, while reducing the amount of fine grid material used, thereby reducing the manufacturing cost of the solar cell 100.

[0056] In some embodiments, at a position where the first fine gate 120 is connected to the first main gate 140 , a height of the first fine gate is greater than or equal to a height of the first main gate 140 .

[0057] Since the cross-sectional area of the first main grid 140 is greater than the cross-sectional area of the first fine grid 120 , at the connection position between the first fine grid 120 and the first main grid 140 , the height of the first fine grid 120 is greater than or equal to the height of the first main grid 140 , which will not cause an increase in resistance at the connection position. At the same time, it can also save the use of the first main grid 140 slurry and reduce production costs.

[0058] In some embodiments, the height of the first fine gate is 4 μm to 7 μm, and the height of the first main gate 140 is 3 μm to 5 μm.

[0059] Example 3

[0060] In some embodiments, a first main gate 140 is further included. The first main gate 140 is connected to a plurality of first fine gates 120 . The width of the first fine gates 120 at a position close to the first main gate 140 is greater than the width of the first fine gates 120 at a position far from the first main gate.

[0061] The first fine gate 120 is wider near its connection with the first main gate 140, increasing its cross-sectional area and reducing its resistance. The first fine gate 120 collects carriers within the P-type region 111. The closer it is to the first main gate 140, the more carriers accumulate on the first fine gate 120, reducing its resistance and enabling smoother carrier transmission within the first fine gate 120. This reduces energy loss during current transmission and thus improves the photovoltaic cell's photoelectric conversion efficiency.

[0062] In some embodiments, the width of the first fine gate 120 decreases along the second direction as the distance from the first main gate 140 increases, and the first fine gate 120 has the largest width at the connection position with the first main gate 140 .

[0063] Along the extension direction of the first fine gate 120, the closer it is to the first main gate 140, the greater the number of hole carriers that need to be transmitted. The width of the first fine gate 120 decreases as the distance from the first main gate 140 increases, and is the widest at the connection point with the first main gate 140. Near the main gate, where the carrier flow is large, the wider first fine gate 120 greatly increases its cross-sectional area, thereby significantly reducing resistance.

[0064] Designing the fine gate width to decrease as the distance from the main gate increases allows for a reasonable reduction in material usage while meeting carrier transport and collection requirements. In areas far from the main gate, where the number of carriers is low, using narrower fine gates can reduce material costs and improve production economics.

[0065] Example 4

[0066] like Figure 4As shown, in some embodiments, a second main gate 150 is further included, which is connected to several second fine gates 130, and the height of the second fine gates 130 at a position close to the second main gate 150 is greater than the height of the second fine gates 130 at a position far away from the second main gate 150.

[0067] In some embodiments, the height of the second fine gate 130 decreases along the second direction as the distance from the second main gate 150 increases, and the height of the second fine gate 130 is the highest at the connection position with the second main gate 150 .

[0068] In some embodiments, at a position where the second fine gate 130 is connected to the second main gate 150 , a height of the second fine gate 130 is greater than or equal to a height of the second main gate 150 .

[0069] The beneficial effects are similar to those of the first main grid 140 and are not described in detail here.

[0070] Example 5

[0071] In some embodiments, a second main gate 150 is further included, which is connected to several second fine gates 130 . The width of the second fine gates 130 at positions close to the second main gate 150 along the second direction is greater than the width of the second fine gates 130 at positions far from the second main gate 150 .

[0072] In some embodiments, the width of the first fine gate 120 decreases as the distance from the first main gate 140 increases, and the first fine gate 120 has the largest width at the connection position with the first main gate 140 .

[0073] The beneficial effects are similar to those of the first main grid 140 and are not described in detail here.

[0074] Example 6

[0075] In some embodiments, an average aspect ratio of at least one first fine gate 120 is greater than an average aspect ratio of at least one second fine gate 130 .

[0076] The aspect ratio of a grating refers to the ratio of its height to its width. A larger aspect ratio indicates a taller, thinner grating, while a smaller aspect ratio indicates a shorter, fatter grating. The "average aspect ratio" indicates the overall aspect ratio of a grating. For example, the aspect ratio of a first grating 120 at a certain location may be smaller than the aspect ratio of a second grating 130 at the same location. For detailed detection methods, refer to the "average height" detection method and will not be elaborated here.

[0077] Increasing the cross-sectional area reduces resistance. A larger average aspect ratio reduces series resistance by increasing the height while ensuring a certain width to maintain good contact with the surrounding P region. This allows hole carriers generated in the P region to be more smoothly transferred through the first fine gate 120 to the first main gate 140, improving the current enrichment capability of the P region.

[0078] In some embodiments, the aspect ratio of the first fine gate 120 , which is at the same distance from the main gate, is greater than the aspect ratio of the second fine gate 130 .

[0079] The second fine grid 130 collects electron carriers from the N-type region, which has a high doping concentration and high carrier mobility. A relatively small aspect ratio ensures that electron transmission is met while preventing the grid from being too tall and obstructing the cell surface, thereby affecting the cell's light absorption. Using different aspect ratios at equal distances from the main grid better adapts to the different carrier characteristics of the P and N regions, achieving efficient carrier collection and transmission.

[0080] It can be understood that the “same distance” from the main grid means that the distances from the detection position on the first fine grid and the detection position on the second fine grid to the main grid are the same. The length of the fine grid is in the micron level, which is already a very small scale. In actual operation, whether it is the accuracy limitation of the measuring equipment itself or the interference of external factors during the measurement process (such as slight deformation of the material caused by temperature and humidity, slight vibration during measurement, etc.), it is difficult to absolutely accurately ensure that the distances between each point are completely equal. Therefore, in this embodiment, the “same distance” can allow an error range of ±10μm. For example, the position on the first fine grid that is 150 microns away from the main grid and the position on the second fine grid that is 145 microns away from the main grid can be considered to be “the same distance” from the main grid.

[0081] In some embodiments, the aspect ratio of the first fine gate 120 and the second fine gate 130 ranges from 0.15 to 0.35.

[0082] In the solar cell 100, the main function of the fine grid is to collect and transmit carriers. When the aspect ratio is in the range of 0.15-0.35, the resistance and carrier collection area of the fine grid can be better balanced. If the aspect ratio is too small, it means that the fine grid is relatively wide and short. Although the contact area with the battery surface may be large, which is conducive to the collection of carriers, the cross-sectional area is relatively small, and the resistance will increase, resulting in increased energy loss of carriers during transmission. On the contrary, if the aspect ratio is too large, the fine grid will become tall and narrow. Although the resistance may decrease, the contact area with the battery surface becomes smaller, which is not conducive to the effective collection of carriers. Therefore, the aspect ratio within this range can enable the fine grid to achieve a better balance in carrier collection and transmission, thereby improving the electrical performance of the battery.

[0083] Example 7

[0084] This embodiment provides a battery assembly including the solar cell 100 described above.

[0085] A battery assembly may include multiple back-contact solar cells. The multiple back-contact solar cells in the battery assembly may be connected in series in sequence to form a battery string. The battery strings may 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 battery cells may be achieved by welding welding strips, and the connection between the battery strings may be achieved by bus bars.

[0086] The battery assembly may also include a metal frame, a backplane, photovoltaic glass, and an adhesive film (not shown). The adhesive film can be filled between the light-facing side of the solar cell and the photovoltaic glass, the backlight side and the backplane, and adjacent solar cells. As a filler, it can be a transparent colloid with good light transmittance and aging resistance. For example, the adhesive film can be EVA film or POE film. The specific choice can be based on actual conditions and is not limited here.

[0087] Photovoltaic glass covers the adhesive film on the light-facing side of the solar cell. This can be ultra-clear glass, which offers high light transmittance, high transparency, and superior physical, mechanical, and optical properties. For example, ultra-clear glass can have a light transmittance exceeding 92%, protecting the solar cell while minimizing its efficiency. The adhesive film also bonds the photovoltaic glass to the solar cell, providing a sealed, insulated, and moisture-proof seal.

[0088] The backsheet can be attached to the film on the backlight side of the solar cell. It provides protection and support for the solar cell, offering reliable insulation, water resistance, and aging resistance. Multiple backsheet options are available, typically including tempered glass, organic glass, and aluminum alloy TPT composite film. The specific backsheet material can be configured based on specific circumstances and is not a limitation here. The backsheet, solar cell, film, and photovoltaic glass assembly can be mounted on a metal frame. The metal frame serves as the primary external support structure for the entire battery assembly and provides stable support and installation for the assembly. For example, the metal frame allows the assembly to be installed in the desired location.

[0089] The beneficial effects of the battery assembly of this embodiment are equivalent to the beneficial effects of the above-mentioned solar cell, and will not be described in detail here.

[0090] Example 8

[0091] This embodiment provides a photovoltaic system including the above-mentioned battery assembly.

[0092] Photovoltaic systems can be used in photovoltaic power stations, such as ground power stations, rooftop power stations, water-surface power stations, etc. They can also be used in equipment or devices that use solar energy to generate electricity, such as user solar power supplies, solar street lights, solar cars, solar buildings, etc. Of course, it is understandable that the application scenarios of photovoltaic systems are not limited to this, that is, photovoltaic systems can be used in all fields that require solar power generation. Taking the photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a junction box and an inverter. The photovoltaic array can be an array combination of multiple battery modules. For example, multiple battery modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the junction box, which can combine the current generated by the photovoltaic array. The combined current flows through the inverter to be converted into the AC power required by the mains power grid and then connected to the mains power network to achieve solar power supply.

[0093] The beneficial effects of the photovoltaic system of this embodiment are equivalent to the beneficial effects of the above-mentioned battery assembly, and will not be described in detail here.

[0094] 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 scope of protection of the present invention.

Claims

1. A solar cell, characterized in that: include: Silicon substrate and fine gate; The silicon substrate includes a plurality of P-type regions and a plurality of N-type regions spaced apart along a first direction, wherein the plurality of P-type regions and the plurality of N-type regions extend along a second direction, and the second direction intersects the first direction; The fine gates extend along the second direction and include a first fine gate disposed in the P-type region and a second fine gate disposed in the N-type region. The average height of at least one of the first fine gates is greater than the average height of at least one of the second fine gates.

2. The solar cell according to claim 1, wherein The device further includes a first main grid connected to a plurality of the first fine grids. The height of the first fine grids at positions close to the first main grids along the second direction is greater than that at positions far from the main grids.

3. The solar cell according to claim 2, wherein The height of the first fine gate decreases as the distance between the first fine gate and the first main gate increases, and the height of the first fine gate is the largest at the connection position with the first main gate.

4. The solar cell according to claim 1 or 2, wherein: It also includes a first main grid connected to the plurality of first fine grids, wherein the width of the first fine grid close to the main grid along the second direction is greater than the width of the first fine grid far from the first main grid.

5. The solar cell according to claim 4, wherein The width of the first fine gate decreases as the distance between the first fine gate and the first main gate increases, and the first fine gate has the largest width at a connection position with the first main gate.

6. The solar cell according to claim 1, wherein It also includes a second main grid connected to a plurality of second fine grids, wherein the height of the second fine grids at positions close to the second main grid along the second direction is greater than the height of the second fine grids at positions far from the second main grid.

7. The solar cell according to claim 6, wherein The height of the second fine gate decreases as the distance between the second fine gate and the second main gate increases, and the height of the second fine gate is the largest at the connection position with the second main gate.

8. The solar cell according to claim 1 or 4, wherein: The device further includes a second main grid connected to a plurality of second fine grids. The width of the second fine grids at positions close to the second main grid is greater than the width at positions far from the second main grid along the second direction.

9. The solar cell according to claim 6, wherein The width of the first fine gate decreases as the distance between the first fine gate and the first main gate increases, and the first fine gate has the largest width at a connection position with the first main gate.

10. The solar cell according to claim 1, wherein An average height-to-width ratio of at least one of the first fine grids is greater than an average height-to-width ratio of at least one of the second fine grids.

11. The solar cell according to claim 3, wherein At a position where the first fine gate is connected to the first main gate, a height of the first fine gate is greater than or equal to a height of the first main gate.

12. The solar cell according to claim 7, wherein At a position where the second fine gate is connected to the second main gate, a height of the second fine gate is greater than or equal to a height of the second main gate.

13. The solar cell according to claim 1, wherein The aspect ratio of the first fine grid which is at the same distance from the main grid is greater than the aspect ratio of the second fine grid.

14. The solar cell according to claim 13, wherein The aspect ratio of the first fine gate and the second fine gate is in the range of 0.15 to 0.

35.

15. A battery assembly, characterized in that: The solar cell comprises the solar cell described in any one of claims 1 to 4.

16. A photovoltaic system, characterized in that: A battery assembly comprising the battery assembly of claim 15.

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