A solar cell, a cell assembly, and a photovoltaic system

Abstract

The application is suitable for the photovoltaic technical field, and provides a solar cell, a cell module and a photovoltaic system.The solar cell comprises a silicon substrate, a plurality of functional layers which are stacked on the silicon substrate, and a silk screen printing area which is provided with a first grid line and a second grid line.The first grid line is provided in the silk screen printing area, and a plurality of first paste points are scattered on the two side edges of the first grid line.The second grid line is provided in the silk screen printing area, and a plurality of second paste points are scattered on the two side edges of the second grid line.The number of the first paste points scattered on the two side edges of the first grid line is less than the number of the second paste points scattered on the two side edges of the second grid line in unit length.The contact between the solder strip and the silver ions is increased in the silk screen printing area, and the welding tension is increased as a whole.The production yield and the quality stability of the cell module are improved, the defective rate caused by the welding problem is reduced, the reliability and the durability of the cell in the actual application are enhanced, and the competitiveness of the solar cell in the photovoltaic market is improved.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic technology, and particularly relates to a solar cell, a battery module, and a photovoltaic system. Background Technology

[0002] In the current booming development of the solar cell industry, cell performance and quality have become the focus of industry attention, with weld pull strength being a key indicator for measuring the reliability of cell modules. The surface of the silicon substrate in traditional solar cells is typically divided into a textured area and a polished area. Due to its special microstructure, the textured area not only increases light absorption to improve photoelectric conversion efficiency but also generates greater friction with the solder ribbon, resulting in higher weld pull strength in this region. However, the polished area has a smooth surface, a small contact area with the solder ribbon, and insufficient friction, leading to a significantly lower weld pull strength compared to the textured area.

[0003] This significant difference in welding pull strength leads to numerous problems. During production, it can easily cause unstable quality of battery modules and a high defect rate. In practical applications, the polished area with low welding pull strength is prone to loose connections and detachment, severely affecting the battery's lifespan and power generation efficiency. How to effectively improve the welding pull strength of the polished area, narrow the gap with the textured area, and achieve a balanced improvement in overall welding pull strength has become a key issue that urgently needs to be addressed in the current solar cell technology field. Summary of the Invention

[0004] This invention provides a solar cell, a cell module, and a photovoltaic system, aiming to solve the problem that the large difference in welding tensile strength between the textured and polished surfaces of the cell affects the cell's lifespan and power generation efficiency.

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

[0006] A silicon substrate includes a silicon substrate and a plurality of functional layers stacked on the silicon substrate, wherein the silicon substrate is respectively provided with a textured area and a polished area;

[0007] A first grid line is set within the velvet area, and several first slurry dots are scattered on both sides of the first grid line;

[0008] A second grid line is set within the polishing area, and several second slurry dots are scattered on both sides of the second grid line;

[0009] Within a unit length, the number of first slurry points scattered on both sides of the first grid line is less than the number of second slurry points scattered on both sides of the second grid line.

[0010] Optionally, the width of the first gate line is smaller than the width of the second gate line.

[0011] Optionally, the width of the first gate line is 12 to 30 μm.

[0012] Optionally, the width of the second gate line is 25–50 μm.

[0013] Optionally, both the first and second gate lines have cross-sections that are wider at the bottom and narrower at the top. The ratio of the height from the bottom surface to the top surface of the first gate line to its bottom width is a first aspect ratio, and the ratio of the height from the bottom surface to the top surface of the second gate line to its bottom width is a second aspect ratio. The first aspect ratio is greater than the second aspect ratio.

[0014] Optionally, when the polished area is an N-type region, the cross-section of the second gate line is trapezoidal.

[0015] Optionally, when the velvet area is an N-type area, the cross-section of the first grid line is a triangle with an arc-shaped apex.

[0016] Optionally, when the polished area is a P-type region, the cross-section of the second grid line is arc-shaped; when the velvet area is a P-type region, the cross-section of the first grid line is arc-shaped; and the curvature of the cross-section of the second grid line is less than the curvature of the cross-section of the first grid line.

[0017] This embodiment provides a battery assembly, including the solar cell described above.

[0018] This embodiment provides a photovoltaic system, including the aforementioned battery module.

[0019] The beneficial effects achieved by this invention are as follows: By separately setting a textured area and a polished area on the silicon substrate, the number of first slurry spots scattered on both sides of the first grid line in the textured area is less than the number of second slurry spots scattered on both sides of the second grid line in the polished area. This increases the contact between the solder ribbon and silver ions in the polished area, resulting in an overall increase in welding tensile strength. This not only improves the production yield and quality stability of the battery module and reduces the defect rate caused by welding problems, but also enhances the reliability and durability of the battery in practical applications, helping to improve the competitiveness of solar cells in the photovoltaic market. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the textured surface region structure of a solar cell according to an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the polished area structure of a solar cell provided in an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the structure of a solar cell provided in an embodiment of the present invention when the polished area is an N-type region;

[0023] Figure 4 This is a schematic diagram of the structure of a solar cell with an N-type textured surface region provided in an embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of the structure of a solar cell provided in an embodiment of the present invention when the polished area is a P-type region;

[0025] Figure 6 This is a schematic diagram of the structure of a solar cell with a textured surface area that is a P-type region, as provided in an embodiment of the present invention.

[0026] Explanation of reference numerals in the attached figures:

[0027] 110. Felt area; 120. Polished area; 130. First grid line; 140. Second grid line; 150. First slurry point; 160. Second slurry point. Detailed Implementation

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] This invention achieves increased welding tensile strength by separately setting a textured area and a polished area on the silicon substrate. The number of first slurry spots scattered along both sides of the first grid line in the textured area is less than the number of second slurry spots scattered along both sides of the second grid line in the polished area. This increases the contact between the solder ribbon and silver ions in the polished area. This not only improves the production yield and quality stability of the battery module and reduces the defect rate caused by welding problems, but also enhances the reliability and durability of the battery in practical applications, contributing to improved competitiveness of solar cells in the photovoltaic market.

[0035] Example 1

[0036] like Figure 1 and Figure 2As shown, this embodiment provides a solar cell, characterized in that it includes:

[0037] The silicon substrate includes a silicon substrate and several functional layers stacked on the silicon substrate. The silicon substrate is respectively provided with a textured area 110 and a polished area 120.

[0038] The first grid line 130 is set in the velvet area 110, and several first slurry dots 150 are scattered on both sides of the first grid line 130.

[0039] The second grid line 140 is set in the polishing zone 120, and several second slurry dots 160 are scattered on both sides of the second grid line 140.

[0040] Within a unit length, the number of first slurry points 150 scattered on both sides of the first grid line 130 is less than the number of second slurry points 160 scattered on both sides of the second grid line 140.

[0041] The silicon substrate is the fundamental structure of a solar cell, consisting of a silicon substrate and several functional layers stacked on it. The silicon substrate, typically a thin sheet of silicon, is the main supporting structure of the cell, providing physical support for the other parts. The functional layers stacked on the silicon substrate have different functions, such as tunneling layers, doped layers, passivation layers, and insulating layers. These different functional layers work together to complete the process of converting light energy into electrical energy in a solar cell.

[0042] A textured area 110 and a polished area 120 are respectively formed on the silicon substrate. The textured area 110 is a region whose surface has been specially treated to form a shape similar to a micro pyramid or other irregular shape. This surface structure can increase the number of light reflections on the surface of the cell, thereby improving the cell's light absorption efficiency. The polished area 120 is a relatively smooth area whose surface has been polished. In this area, light reflection is more regular and is mainly used for some specific electrical performance optimization or other process requirements.

[0043] The silicon substrate 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 arranged opposite each other. Specifically, the textured area 110 and the polished area 120 can both be placed on the same surface of the silicon substrate, for example, both textured area 110 and polished area 120 can be placed on the back-lighting surface; alternatively, the textured area 110 and polished area 120 can be placed on different surfaces of the silicon substrate, for example, the textured area 110 can be placed on the light-facing surface, and the polished area 120 can be placed on the back-lighting surface. No limitation is made here.

[0044] The first grid line 130 and the second grid line 140 mainly serve to collect current in the entire structure. In optoelectronic devices such as solar cells, photogenerated carriers (electrons and holes) need to be transferred to the external circuit through the grid lines to realize the output of electrical energy.

[0045] Both the first grid line 130 and the second grid line 140 are printed using a paste, preferably a metal paste with good conductivity, such as silver paste. The metal paste contains metal particles, an organic carrier, and additives. The organic carrier provides the paste with suitable viscosity and flowability, facilitating printing; the additives improve the printability and sintering performance of the paste. The first grid line 130 and the second grid line 140 can be printed using the same metal paste or different metal pastes; this is not limited here.

[0046] The commonly used grid line printing process is screen printing. The designed grid line pattern is created on a screen, and a squeegee forces metal paste through the mesh of the screen onto the textured area 110 and polished area 120 of the silicon substrate. During the printing process, the paste is precisely deposited on the silicon substrate surface according to the screen pattern, forming the initial shape of the grid lines. The coated silicon substrate needs to undergo a sintering process, where the organic carrier in the paste volatilizes at high temperature, and the metal particles fuse and sinter together to form solid grid lines with good conductivity. Other grid line printing processes can also be used, and are not limited here.

[0047] Several first paste dots 150 are scattered on both sides of the first grid line 130. The first paste dots 150 and the first grid line 130 are printed with the same metal paste. Several first paste dots 150 are set on both sides of the extension direction of the first grid line 130. The first paste dots 150 are free on both sides of the first grid line 130, close to the first grid line 130 but not in contact with the first grid line 130.

[0048] Several second paste dots 160 are scattered on both sides of the second grid line 140. The second paste dots 160 are printed with the same metal paste as the second grid line 140. Several second paste dots 160 are set on both sides of the extension direction of the second grid line 140. The second paste dots 160 are free on both sides of the second grid line 140, close to the second grid line 140 but not in contact with the second grid line 140.

[0049] During subsequent assembly, solar cells are welded to solder ribbons. Good welding tensile strength can ensure the stability and reliability of the connection between the cell and the solder ribbon, reducing the risk of loosening or falling off during subsequent processing, transportation and long-term use, thereby ensuring the overall performance and service life of the solar cell module.

[0050] In this embodiment, the silicon substrate of the solar cell is divided into a textured region 110 and a polished region 120. The textured region 110 has a special microscopic surface structure, which increases the number of light reflections on the cell surface, improves the cell's light absorption efficiency, and also provides more contact points and friction for the connection between the solder ribbon and the cell surface. Therefore, the textured region 110 itself has relatively high welding pull strength. On the other hand, the polished region 120 has a smoother surface, and its contact area and friction with the solder ribbon are relatively small, resulting in a lower welding pull strength than that of the textured region 110.

[0051] To address the issue of insufficient welding pull in the polished area 120, the number of first slurry spots 150 scattered on both sides of the first grid line 130 per unit length is less than the number of second slurry spots 160 scattered on both sides of the second grid line 140. These slurry spots typically contain silver ions. When the solder ribbon is welded to the battery surface, it can come into contact with these silver ions. Silver has good electrical conductivity and chemical activity, enabling it to form relatively strong chemical bonds and physical connections with the solder ribbon.

[0052] The second slurry point 160 is scattered in the polished area 120, allowing the solder ribbon to interact with more silver ions when it comes into contact with the polished area 120. This increases the connection strength between the solder ribbon and the cell surface, thereby improving the welding pull force of the polished area 120. In this way, the difference in welding pull force between the textured area 110 and the polished area 120 is reduced, resulting in a more balanced and reliable welding performance for the entire solar cell.

[0053] In this embodiment, by respectively setting a textured area 110 and a polished area 120 on the silicon substrate, the number of first slurry points 150 scattered on both sides of the first grid line 130 in the textured area 110 is less than the number of second slurry points 160 scattered on both sides of the second grid line 140 in the polished area 120. This increases the contact between the solder ribbon and silver ions in the polished area 120, thereby increasing the overall welding tensile strength. This not only improves the production yield and quality stability of the battery module and reduces the defect rate caused by welding problems, but also enhances the reliability and durability of the battery in practical applications, helping to improve the competitiveness of solar cells in the photovoltaic market.

[0054] Example 2

[0055] In some embodiments, the width of the first gate line 130 is smaller than the width of the second gate line 140.

[0056] The first grid line 130 and the second grid line 140 may not have completely uniform widths; that is, the edges of the first grid line 130 and the second grid line 140 may be undulating, resulting in the specific widths of the first grid line 130 and the second grid line 140 not being completely consistent at various locations. Here, "width" refers to the average width, which is calculated by dividing the grid line along its length, measuring the width at each division point, and then taking the average of these width values. By calculating the average width, the overall width of the grid line can be comprehensively considered, allowing for comparison of differences in width between different grid lines.

[0057] The width of the first grid line 130 is smaller than the width of the second grid line 140. In the textured region 110, since the main goal is to improve light absorption, the smaller width of the first grid line 130 reduces the obstruction of sunlight, allowing more light to reach the surface of the textured region 110 and increasing the generation of photogenerated carriers. In contrast, the polished region 120 focuses more on optimizing electrical performance. The larger width of the second grid line 140 provides a larger conductive area, reduces resistance, and improves carrier transport efficiency, thereby enhancing the overall performance of the solar cell.

[0058] Example 3

[0059] In some embodiments, the width of the second gate line 140 is 25–50 μm.

[0060] The width of the second gate line 140 is 25 to 50 μm, that is, the width of the second gate line 140 can vary between 25 and 50 μm. Specifically, the second gate line 140 can be a non-uniform line shape, having a second protrusion and a second narrowing portion. The widest part of the second protrusion is 50 μm, and the width of the second narrowing portion is 25 μm.

[0061] This width range strikes a good balance between minimizing light shading in the textured area 110 and ensuring sufficient conductivity. If the width is too large, it increases light shading and reduces light absorption efficiency; if the width is too small, the resistance of the grid lines increases, leading to increased energy loss during carrier transport. An appropriate width range helps improve the photoelectric conversion efficiency of the solar cell.

[0062] Example 4

[0063] In some embodiments, the width of the first gate line 130 is 12 to 30 μm.

[0064] The width of the first gate line 130 is 12 to 30 μm, that is, the width of the first gate line 130 varies between 12 and 30 μm. Specifically, the first gate line 130 can be a non-uniform line shape, having a first protrusion and a first narrowing. The widest part of the first protrusion is 30 μm, and the width of the first narrowing is 12 μm.

[0065] Within the polished region 120, this width range satisfies certain conductivity requirements while also allowing for light transmission and utilization to a certain extent. Within this width range, photogenerated carriers generated in the polished region 120 can be effectively collected and transported, while unnecessary light obstruction is reduced, thereby improving the overall performance of the battery.

[0066] Example 5

[0067] In some embodiments, the cross-sections of the first gate line 130 and the second gate line 140 are both wider at the bottom and narrower at the top. The ratio of the height from the bottom surface to the top surface of the first gate line 130 to the width of the bottom surface is a first aspect ratio, and the ratio of the height from the bottom surface to the top surface of the second gate line 140 to the width of the bottom surface is a second aspect ratio. The first aspect ratio is greater than the second aspect ratio.

[0068] This refers to the ratio of the height from the bottom to the top of the grid line to the width of the bottom surface. This ratio reflects the shape characteristics of the grid line, and different aspect ratios will affect the electrical and optical performance of the grid line.

[0069] In the textured region 110, the first grid line 130 has a large aspect ratio. Its higher height increases the contact area with the textured region 110, thus better collecting photogenerated carriers. At the same time, its shape, wider at the bottom and narrower at the top, can reduce light obstruction to some extent. In the polished region 120, the second grid line 140 has a smaller aspect ratio. Its wider bottom surface can provide a larger conductive area, reducing resistance and facilitating carrier transport, thereby optimizing the electrical and optical performance of the battery.

[0070] Example 6

[0071] like Figure 3 As shown, in some embodiments, when the polishing area 120 is an N-type region, the cross-section of the second gate line 140 is trapezoidal or approximately trapezoidal.

[0072] The cross-section of the second gate line 140 is trapezoidal or approximately trapezoidal. The cross-section of the second gate line 140 has parallel upper and lower bases, meaning the side of the second gate line 140 facing away from the silicon substrate is a plane parallel to the silicon substrate. Understandably, the side of the second gate line 140 facing away from the silicon substrate may not be a perfectly flat plane; it can be approximated as a plane. An approximate trapezoid is not a trapezoid in the strict sense; it refers to a shape similar to a trapezoid but not necessarily perfectly satisfying the definition of a trapezoid. In other words, this shape looks very much like a trapezoid, but its parallelism between opposite sides may not be absolutely precise, with a small deviation (not exceeding 2°).

[0073] The trapezoidal structure, wider at the bottom and narrower at the top, increases the contact area with the N-type polished region 120, improving carrier collection efficiency. Simultaneously, the relatively narrow top reduces light obstruction, which is beneficial for improving the photoelectric conversion efficiency of the cell. The electrical characteristics of the N-type region allow the trapezoidal cross-section of the second grid line 140 to better integrate with this region.

[0074] Example 7

[0075] like Figure 4 As shown, in some embodiments, when the velvet area 110 is an N-type area, the cross-section of the first grid line 130 is a triangle with an arc-shaped apex.

[0076] The cross-section of the first gate line 130 is a triangle with an arc-shaped apex, not a standard triangle. That is, one apex of the original triangle is replaced by an arc, forming a shape that resembles a triangle but with an arc-shaped apex. In other words, the side of the first gate line 130 facing away from the silicon substrate is not a complete plane, but an arc surface.

[0077] The electrical properties of the P-type region differ from those of the N-type region. The triangular cross-section with an arc-shaped apex can adapt to the carrier distribution and transport characteristics of the N-type textured region 110. This shape can ensure a certain conductive area for collecting carriers while reducing light obstruction to a certain extent, thereby improving the performance of the battery in the N-type textured region 110.

[0078] Example 8

[0079] like Figure 5 and Figure 6 As shown, in some embodiments, when the polished area 120 is a P-type area, the cross-section of the second gate line 140 is arc-shaped, and when the velvet area 110 is a P-type area, the cross-section of the first gate line 130 is arc-shaped, and the curvature of the cross-section of the second gate line 140 is less than the curvature of the cross-section of the first gate line 130.

[0080] The cross-sections of the second grid line 140 and the first grid line 130 within the P-type region exhibit an arc shape. This arc shape is a continuous, smooth curve, creating a fluid transition on the surface compared to a straight line. The curvature of the cross-section of the second grid line 140 is less than that of the cross-section of the first grid line 130; that is, the curvature of the arc shape of the second grid line 140 is relatively small, with a smaller radius and less abrupt undulations, resulting in a gentler change in the height of the grid line on the cross-section. In contrast, the arc shape of the cross-section of the first grid line 130 is relatively large, with a larger radius and greater undulations, resulting in a more dramatic change in the height of the first grid line 130 on the cross-section. This contrasts sharply with the relatively flat and small-radius arc cross-section of the second grid line 140 in the P-type textured area 110; this large-radius arc shape visually resembles a portion of a semicircle or ellipse.

[0081] In the P-type region, holes are the dominant charge carriers. The polished region 120 has a relatively smooth surface with high reflectivity, which is detrimental to light absorption. However, it has advantages in welding and electrical contact; its surface smoothness helps the grid lines adhere better to the battery surface, reducing contact resistance. The textured region 110, on the other hand, has a microscopically rough surface structure, which increases the number of reflections and scatterings of light on the battery surface, improving the battery's light absorption efficiency and thus increasing the generation of photogenerated charge carriers. However, relatively speaking, the contact between the grid lines and the textured region 110 may not be as tight as that with the polished region 120.

[0082] On the one hand, the smooth surface of the polished area 120 and the small curvature of the second grid line 140 mean that the grid line is more gently sloping, allowing for a large-area, close contact between the grid line and the P-type surface of the polished area 120. During welding, the increased contact area between the solder ribbon and the grid line improves the strength and stability of the weld. Simultaneously, the smaller curvature reduces stress concentration during welding, lowering the risk of cracks or detachment at the weld joint, thus improving the welding quality and reliability of the battery module. On the other hand, the uneven surface of the textured area 110 and the large curvature of the first grid line 130 allow the grid line to better adapt to the undulating structure of the textured surface. The grid line can be embedded more deeply into the depressions of the textured surface, increasing the contact points and contact area with the P-type surface of the textured area 110, thereby improving the adhesion between the grid line and the battery surface, which also helps to improve welding tensile strength and welding stability.

[0083] On the other hand, the good contact between the second grid line 140 with its smaller curvature and the P-type surface of the polished region 120 reduces contact resistance. During battery operation, holes are transported from the P-type region to the external circuit through the grid lines. Low contact resistance reduces energy loss and improves the battery's fill factor and photoelectric conversion efficiency. Although the textured region 110 has a rough surface, the first grid line 130 with its larger curvature can make sufficient contact with the textured surface, ensuring that holes can be smoothly transported from the P-type region to the grid lines. Furthermore, since the textured region 110 has high light absorption efficiency and generates more photogenerated carriers, the first grid line 130 can collect these carriers more effectively, further improving the battery's current output.

[0084] In this embodiment, the curvature of the cross-section of the second grid line 140 is less than that of the cross-section of the first grid line 130. The grid line design with different curvatures adapts to the different surface characteristics of the polished area 120 and the textured area 110, enabling the battery to achieve good welding and electrical contact in different areas. This helps to improve the overall stability and consistency of the battery, reduce performance fluctuations caused by regional differences, and thus improve the overall quality and lifespan of the battery module.

[0085] Example 9

[0086] This embodiment also provides a battery assembly, including the solar cell described in the above embodiment.

[0087] A battery module may include multiple back-contact solar cells. These multiple back-contact solar cells 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 collection and output. For example, the connection between the individual cells can be achieved by welding solder strips, or the connection between the individual battery strings can be achieved by busbars.

[0088] 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 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.

[0089] Photovoltaic glass can be applied to the encapsulating film on the light-facing side of a 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%, protecting the solar cell while minimizing impact on its efficiency. Simultaneously, the encapsulating film bonds the photovoltaic glass and the solar cell together, providing sealing, insulation, and waterproofing / moisture protection for the solar cell.

[0090] The backsheet can be attached to the encapsulating film on the back side of the 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 encapsulating film, etc. The specific choice depends on the specific circumstances and is not limited here. The backsheet, solar cell, encapsulating 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.

[0091] The beneficial effects of the battery module in this embodiment are equivalent to those of the solar cell described above, and will not be repeated here.

[0092] Example 10

[0093] This embodiment also provides a photovoltaic system, including the battery module in the above embodiment.

[0094] 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.

[0095] 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.

[0096] It is understood that those skilled in the art can combine various implementation methods in the above embodiments under the guidance of the above examples to obtain technical solutions with multiple implementation methods.

[0097] The above are merely 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 within the protection scope of the present invention.

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