A battery module and photovoltaic system

Abstract

This utility model relates to the field of photovoltaic technology and provides a battery module and a photovoltaic system. The battery module includes: a battery string, solder ribbons, and busbars; the battery string includes a plurality of back-contact solar cells arranged in an overlapping manner along a first direction, adjacent back-contact solar cells are connected in series by solder ribbons, and the back-contact solar cells include a first cell and a second cell; the solder ribbons extend along the first direction and are arranged on the back side of the back-contact solar cell array, including a first solder ribbon and a second solder ribbon; the busbars are stacked on the second cell near the edge of the first cell and extend along a second direction; the first solder ribbon is electrically connected to the busbars, and the second solder ribbon is insulated from the busbars, and the overlap length between the first solder ribbon and the busbars is greater than the overlap length between a portion of the second solder ribbon and the busbars. This increases the contact area between the first solder ribbon and the busbars, thereby improving the current collection and transmission efficiency of the entire battery module.

Description

Technical Field

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

[0002] Traditional solar cell modules suffer from numerous problems in cell arrangement and connection methods. Inadequate cell arrangement in the past has led to low current collection and transmission efficiency. Using conventional series connection methods results in limited contact area between the solder ribbons and busbars, leading to high contact resistance and hindering the effective transmission of current from the cells to the busbars, causing energy loss. Furthermore, some designs cannot accommodate differentiated connections between different solder ribbons and busbars, failing to balance current collection and electrical isolation. These issues ultimately limit the output power of the solar module, preventing it from fully utilizing the cells' power generation capacity. Therefore, a new cell arrangement and connection method is needed to address these problems, improve current collection and transmission efficiency, and increase the module's output power. Utility Model Content

[0003] This invention provides a battery module and a photovoltaic system, aiming to solve the problem that the output power of the battery module is limited and the power generation capacity of the battery cells cannot be fully utilized.

[0004] This utility model is implemented as follows: a battery assembly includes: a battery string, a solder strip, and a busbar; The battery string includes a plurality of back-contact solar cells arranged in an overlapping manner along a first direction. Adjacent back-contact solar cells are connected in series by the solder strip. Each back-contact solar cell includes a first cell and a second cell arranged along the first direction. The solder strips extend along the first direction and are arranged on the back side of the back-contacting solar cell array, including a first solder strip and a second solder strip; The busbar is stacked on the edge of the second battery cell near the first battery cell and extends along the second direction, which intersects the second direction; the first solder strip is electrically connected to the busbar, and the second solder strip is insulated from the busbar; One end of the first solder strip is positioned above the busbar, and one end of a portion of the second solder strip is positioned below the busbar. Along the first direction, the length by which the orthographic projection of the first solder strip overlaps with the orthographic projection of the busbar is greater than the length by which the orthographic projection of a portion of the second solder strip overlaps with the orthographic projection of the busbar.

[0005] Optionally, the length d1 by which the orthographic projection of the first solder strip overlaps with the orthographic projection of the busbar, and the length d2 by which the orthographic projection of the second solder strip overlaps with the orthographic projection of the busbar, are both less than 5 mm.

[0006] Optionally, the length of d1 ranges from 3 to 8 mm.

[0007] Optionally, the length of d2 ranges from 3 to 8 mm.

[0008] Optionally, along the first direction, a plurality of second welding strips are staggered, and along the second direction, a plurality of second welding strips are staggered.

[0009] Optionally, the axes of the orthographic projections of the first solder strip and a portion of the second solder strip are collinear.

[0010] Optionally, it also includes a barrier strip, which extends along a second direction, and the barrier strip and the busbar are stacked together; The busbar and the isolation strip are disposed between the first solder strip and the second solder strip, with the first solder strip in contact with the busbar and the second solder strip in contact with the isolation strip.

[0011] Optionally, one end of the first solder strip is positioned above the busbar, and one end of a portion of the second solder strip is positioned below the busbar, with the orthographic projections of the first solder strip and the portion of the second solder strip having a first spacing along the first direction.

[0012] Optionally, the length of the first spacing is 1 to 4 mm.

[0013] Optionally, the width of the first solder strip and the width of the second solder strip are the same.

[0014] This utility model also provides a photovoltaic system, including the above-mentioned battery components.

[0015] The beneficial effects achieved by this invention are as follows: By employing back-contact solar cells arranged in overlapping rows along a first direction to form a cell string, and using solder ribbons to connect the cells in series, a busbar extending along a second direction is provided. This achieves current collection between the first solder ribbon and the busbar, as well as electrical isolation between the second solder ribbon and the busbar. The overlap length between the orthographic projections of the first solder ribbon and the busbar is greater than the overlap length between the orthographic projections of the second solder ribbon and the busbar. This increases the contact area between the first solder ribbon and the busbar, reducing contact resistance and enabling more efficient transmission of current generated by the solar cells to the busbar. This improves the current collection and transmission efficiency of the entire solar module, thereby increasing the output power of the solar module. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the battery assembly provided by this utility model; Figure 2 This is a cross-sectional view along the AA direction provided by this utility model; Figure 3This is another AA-direction cross-sectional view provided by this utility model.

[0017] Explanation of reference numerals in the attached figures: 100. Battery module; 110. Battery string; 111. Back contact solar cell; 1111. First cell; 1112. Second cell; 120. Welding ribbon; 121. First welding ribbon; 122. Second welding ribbon; 1221. First connecting welding ribbon; 1222. Second connecting welding ribbon; 130. Busbar; 140. Separator. Detailed Implementation

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] This invention employs back-contact solar cells arranged in an overlapping pattern along a first direction to form a cell string. The cells are connected in series using solder ribbons, and a busbar extending along a second direction is provided. This achieves current collection between the first solder ribbon and the busbar, and electrical isolation between the second solder ribbon and the busbar. The overlap length between the orthographic projections of the first solder ribbon and the busbar is greater than the overlap length between the orthographic projections of the second solder ribbon and the busbar. This increases the contact area between the first solder ribbon and the busbar, reducing contact resistance and enabling more efficient transmission of current generated by the solar cells to the busbar. This improves the current collection and transmission efficiency of the entire solar module, thereby increasing the output power of the solar module.

[0025] Example 1 like Figures 1 to 3 As shown, this embodiment provides a battery assembly 100 including: a battery string 110, a solder strip 120, and a busbar 130; The battery string 110 includes a plurality of back-contact solar cells 111 arranged in an overlapping manner along a first direction. Adjacent back-contact solar cells 111 are connected in series by solder strips 120. The back-contact solar cells 111 include a first cell 1111 and a second cell 1112 arranged along the first direction. The solder ribbon 120 extends along a first direction and is arranged on the back side of the back contact solar cell 111 group, including a first solder ribbon 121 and a second solder ribbon 122. Busbar 130 is stacked on the edge of the second cell 1112 near the first cell 1111, and extends along the second direction, with the first direction intersecting the second direction; the first solder strip 121 is electrically connected to the busbar 130, and the second solder strip 122 is insulated from the busbar 130. One end of the first solder strip 121 is positioned above the busbar 130, and one end of a portion of the second solder strip 122 is positioned below the busbar 130. Along the first direction, the length of overlap between the orthographic projection of the first solder strip 121 and the orthographic projection of the busbar 130 is greater than the length of overlap between the orthographic projection of the portion of the second solder strip 122 and the orthographic projection of the busbar 130.

[0026] The battery string 110 includes several back-contact solar cells 111. The positive and negative electrodes of each back-contact solar cell 111 are located on its back side. Compared to the traditional structure where the positive and negative electrodes are located on the front and back sides of the back-contact solar cell 111 respectively, this reduces the shading of light by the front electrode and improves the solar cell's absorption efficiency. In the back-contact solar cells 111, the positive and negative electrodes extend along a second direction and are alternately arranged along a first direction.

[0027] The second direction intersects with the first direction, such as Figure 1 As shown, the first direction can be the longitudinal direction of the back contact battery, and the second direction can be the transverse direction of the back contact battery, with the two directions being perpendicular to each other. Of course, in other embodiments, the first and second directions can also be other directions, for example, they can be the diagonal directions of the silicon substrate, and no specific limitation is made here.

[0028] The back-contact solar cells 111 are arranged in an overlapping manner along a first direction, that is, the back-contact solar cells 111 are arranged along the first direction, and adjacent back-contact solar cells 111 have a stacked area. Specifically, the back-contact solar cells 111 have a light-facing surface and a back-facing surface arranged opposite each other. Along the extension direction of the back-contact solar cells, the back-contact solar cells 111 have opposite first edges and second edges. The back-facing surface of the first back-contact solar cell 111 near the second edge is in contact with the light-facing surface of the second back-contact solar cell 111 near the first edge. The overlapping area of ​​the two back-contact solar cells 111 is the stacked area.

[0029] The back contact solar cell 111 includes a first cell 1111 and a second cell 1112. The first cell 1111 and the second cell 1112 are arranged along a first direction, that is, the second cell 1112 is arranged after the first cell 1111 is arranged. The back surface of the first cell 1111 overlaps with the light-facing surface of the second cell 1112.

[0030] The solder ribbon 120 is used to collect the charge carriers generated on each back-contact solar cell 111. The solder ribbon 120 connects two adjacent back-contact solar cells 111. The solder ribbon 120 includes a first solder ribbon 121 and a second solder ribbon 122. The first solder ribbon 121 is electrically connected to the busbar 130 and is responsible for connecting adjacent first solar cells 1111 in series with other solar cells (excluding second solar cells 1112), ensuring smooth current conduction in the solar cell string 110. Simultaneously, the first solder ribbon 121 is electrically connected to the busbar 130, transmitting the current generated in the solar cell string 110 to the busbar 130 for further output of electrical energy. The second solder ribbon 122 is not electrically connected to the busbar 130 and connects other solar cells besides those connected by the first solder ribbon 121. It can connect adjacent second solar cells 1112 with other solar cells (possibly first solar cells 1111).

[0031] Specifically, along the first direction, a plurality of second welding strips 122 are staggered, and along the second direction, a plurality of second welding strips 122 are staggered.

[0032] In a battery string 110, the Nth, N+1th, and N+2th battery cells (N is a positive integer greater than 1) are arranged sequentially along a first direction. The positive terminal of the Nth battery cell is connected to the negative terminal of the N+1th battery cell via multiple second solder strips 122, and the positive terminal of the N+1th battery cell is connected to the negative terminal of the N+2th battery cell via multiple second solder strips 122. The N+1th battery cell is not the first battery cell 1111. When the N+1th battery cell is the first battery cell 1111, the positive terminal of the Nth battery cell is connected to the negative terminal of the N+1th battery cell via a first solder strip 121. The multiple second solder strips 122 are staggered, allowing the second solder strips 122 to connect the positive and negative terminals of adjacent battery cells more directly, effectively shortening the current transmission path between battery cells. This helps reduce resistance, minimize energy loss during transmission, ensure smooth current flow, and improve the power generation efficiency of the battery module 100.

[0033] In some embodiments, the length of the first solder strip 121 is greater than the length of the second solder strip 122, and the first solder strip 121 has an overlap extending in a first direction, the overlap being electrically connected to the busbar 130.

[0034] Busbar 130 extends along a second direction and is positioned near the edge of the second solar cell 1112, close to the edge of the first solar cell 1111. The busbar 130 is positioned close to or at least partially covers the stacked area of ​​the first solar cell 1111 and the second solar cell 1112. The busbar 130 collects current conducted from multiple first solder strips 121, concentrating the dispersed current and ultimately delivering it to the output terminal of the battery assembly 100.

[0035] The second direction intersects the first 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, with the two being perpendicular to each other. Of course, in other embodiments, the first and second directions can also be other directions, for example, they can be the diagonal directions of the silicon substrate, and no specific limitation is made here.

[0036] The first solder strip 121 is electrically connected to the busbar 130. That is, the first solder strip 121 can be directly connected to the busbar 130 or connected through other conductive media. The second solder strip 122 is insulated from the busbar 130. That is, an insulating medium is provided between the second solder strip 122 and the busbar 130. Specifically, it can be coated with insulating glue, a spacer strip 140, or other insulating medium, which is not limited here.

[0037] One end of the first solder strip 121 is positioned above the busbar 130, and one end of the second solder strip 122 is positioned below the busbar 130. The busbar 130 has two opposing sides, one side facing the back-contact solar cell 111 and the other side facing away from the back-contact solar cell 111. One end of the first solder strip 121 is positioned on the side facing away from the back-contact solar cell 111, and one end of the second solder strip 122 is positioned on the side facing the back-contact solar cell 111. It should be noted that "end" refers to the portion at the beginning or end along the extension direction of the solder strip 120, and is not necessarily a precise endpoint, but includes the endpoint and a small area near the endpoint.

[0038] Each back-contact solar cell 111 in the battery string 110 is connected in series. A busbar 130 is located at the end of the second solar cell 1112 near the first solar cell 1111. The side of the busbar 130 facing the back-contact solar cell 111 is provided with an insulating medium to block the connection with the busbar 130. The insulating medium can be insulating glue, insulating strip, etc. The first solder ribbon 121 is electrically connected to the effective welding position of the first solar cell 1111, and the end of the first solder ribbon 121 near the second solar cell 1112 is electrically connected to the busbar 130, thereby enabling the busbar 130 to draw current from the battery string 110.

[0039] like Figure 2 and Figure 3As shown, along the first direction, the overlap length between the orthographic projection of the first solder strip 121 and the orthographic projection of the busbar 130 is greater than the overlap length between the orthographic projection of the second solder strip 122 and the orthographic projection of the busbar 130. Typically, the widths of the first solder strip 121 and the second solder strip 122 are the same. The first solder strip 121 is electrically connected to the busbar 130, undertaking the important task of efficiently collecting and transmitting the current generated by the battery cells to the busbar 130. On one hand, the longer overlap length means a larger contact area between the first solder strip 121 and the busbar 130, which reduces contact resistance. Lower contact resistance reduces energy loss during current transmission, improves the power generation efficiency of the battery module 100, and allows more electrical energy to be effectively transmitted to the busbar 130 and output. On the other hand, the larger overlap length increases the connection area between the first solder strip 121 and the busbar 130, making their connection more robust. During the use of the battery module 100, it may be affected by factors such as vibration and temperature changes. If the connection is not robust, it can easily lead to poor contact or even disconnection. A longer overlap length can improve the stability of the connection, reduce the probability of failure caused by external factors, and extend the service life of the battery assembly 100.

[0040] In this embodiment, back-contact solar cells 111 are arranged in overlapping rows along a first direction to form a cell string 110. Solder ribbons 120 are used to connect the cells in series. A busbar 130 extending along a second direction is provided to achieve current collection between the first solder ribbon 121 and the busbar 130, and electrical isolation between the second solder ribbon 122 and the busbar 130. The overlap length between the orthographic projection of the first solder ribbon 121 and the orthographic projection of the busbar 130 is greater than the overlap length between the orthographic projection of the second solder ribbon 122 and the orthographic projection of the busbar 130. This increases the contact area between the first solder ribbon 121 and the busbar 130, reducing contact resistance. This allows for more efficient transmission of current generated by the cells to the busbar 130, improving the current collection and transmission efficiency of the entire battery module 100, and ultimately increasing the output power of the battery module 100.

[0041] The battery module 100 may also include a metal frame, a backsheet, photovoltaic glass, and an encapsulating film (not shown in the figures). The encapsulating film may be filled between the light-facing side of the back-contact solar cell 111 and the photovoltaic glass, the back-facing side and the backsheet, and adjacent cells, etc. As a filler, it may be a transparent colloid with good light transmittance and aging resistance. For example, the encapsulating film may be an EVA film or a POE film, and the specific choice can be made according to the actual situation, without limitation.

[0042] Photovoltaic glass can be applied to the encapsulating film on the light-facing side of the back-contact solar cell 111. The 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 back-contact solar cell while minimizing impact on its efficiency. Simultaneously, the encapsulating film bonds the photovoltaic glass and the back-contact solar cell together, providing sealing, insulation, and waterproofing / moisture protection for the back-contact solar cell.

[0043] The backsheet can be attached to the adhesive film on the back side of the back contact solar cell 111. The backsheet protects and supports the back contact solar cell 111, and has reliable insulation, water resistance, and aging resistance. Multiple options are available for the backsheet, typically tempered glass, acrylic glass, aluminum alloy TPT composite adhesive film, etc., and the specific choice depends on the specific circumstances and is not limited here. The backsheet, back contact solar cell 111, adhesive film, and photovoltaic glass can be mounted on a metal frame. The metal frame serves as the main external support structure for the entire battery module 100, providing stable support and installation for the battery module 100. For example, the battery module 100 can be installed at the desired location using the metal frame.

[0044] In some embodiments, the length d1 by which the orthographic projection of the first solder strip 121 overlaps with the orthographic projection of the busbar 130, and the length d2 by which the orthographic projection of the second solder strip 122 overlaps with the orthographic projection of the busbar 130, are both less than 5 mm.

[0045] During the lamination process of the battery module 100, a certain pressure is applied to the entire module. When d1-d2<5mm, the difference in overlap length between the first solder ribbon 121 and the second solder ribbon 122 and the busbar 130 is relatively small. This means that under the lamination pressure, the pressure can be distributed relatively evenly in the connection area between the solder ribbon 120 and the busbar 130.

[0046] For the connection between the first solder strip 121 and the busbar 130, and the overlapping area between the second solder strip 122 and the busbar 130, the pressure they bear is similar due to the small difference in length. This prevents stress concentration in the solar cell caused by excessive local pressure. Uniform pressure distribution helps ensure a stable structure of the solar cell during lamination, avoiding internal damage caused by uneven stress, thereby improving the overall quality and reliability of the solar module 100.

[0047] In some embodiments, the length of d1 ranges from 3 to 8 mm.

[0048] In the photovoltaic module 100, the width direction of the busbar 130 is consistent with the first direction. The width of the busbar 130 is typically around 5 to 10 mm. When d1 is between 3 and 8 mm, the first solder ribbon 121 and the busbar 130 have sufficient and suitable contact area, allowing charge carriers to be smoothly transferred from the first solder ribbon 121 to the busbar 130. When d1 exceeds 8 mm, it increases the amount of solder ribbon 120 used and may also require a wider busbar 130 to match, which increases material costs. A value of d1 within the range of 3 to 8 mm allows for reasonable control of material usage while meeting electrical and mechanical performance requirements. Combined with the common width of the busbar 130, cost can be optimized while ensuring performance.

[0049] In some embodiments, the length of d2 ranges from 3 to 8 mm.

[0050] In the photovoltaic module 100, the width direction of the busbar 130 is consistent with the first direction. The width of the busbar 130 is typically around 5 to 10 mm. When d2 is between 3 and 8 mm, the second solder ribbon 122 and the busbar 130 have sufficient and suitable contact area, allowing charge carriers to be smoothly transferred from the second solder ribbon 122 to the busbar 130. When d2 exceeds 8 mm, it increases the amount of solder ribbon 120 used and may also require a wider busbar 130 to match, which increases material costs. A value of d2 within the range of 3 to 8 mm allows for reasonable control of material usage while meeting electrical and mechanical performance requirements. Combined with the common width of the busbar 130, cost can be optimized while ensuring performance.

[0051] Example 2 In some embodiments, the battery assembly 100 further includes a separator 140 extending along a second direction, and the separator 140 and the busbar 130 are stacked together. The busbar 130 and the isolation strip 140 are disposed between the first welding strip 121 and the second welding strip 122. The first welding strip 121 is in contact with the busbar 130, and the second welding strip 122 is in contact with the isolation strip 140.

[0052] The insulating strip 140 is made of insulating material and is used to block circuit connections. The insulating strip 140 also extends along the second direction and is stacked with the busbar 130. One side of the insulating strip 140 contacts the side of the busbar 130 facing the back contact solar cell 111, and the other side faces the back contact solar cell 111. The other side of the busbar 130 faces away from the back contact solar cell 111. The busbar 130 and the insulating strip 140 are disposed between the first solder strip 121 and the second solder strip 122. One end of the first solder strip 121 is positioned above the busbar 130, that is, the first solder strip 121 contacts the side of the busbar 130 facing away from the back contact solar cell 111. One end of the second solder strip 122 is positioned below the insulating strip 140, that is, the second solder strip 122 contacts the side of the insulating strip 140 facing away from the back contact solar cell 111.

[0053] The installation of the separator 140 is a relatively simple physical process. It only requires accurate placement of the separator 140 on the edge of the second cell 1112 near the first cell 1111. This process does not require complex equipment or technology. The installation of the separator 140 is fast, and multiple cell modules 100 can be assembled in a short time, making it suitable for large-scale industrial production.

[0054] Example 3 In some embodiments, one end of the first solder strip is positioned above the busbar, and one end of a portion of the second solder strip is positioned below the busbar. The orthographic projections of the first solder strip and the portion of the second solder strip have a first spacing along a first direction.

[0055] Specifically, the second solder strip 122 includes a first connecting solder strip 1221 and a second connecting solder strip 1222. In a first direction, the first connecting solder strip 1221 and the second connecting solder strip 1222 are alternately arranged. In a second direction, the first connecting solder strip 1221 and the second connecting solder strip 1222 are alternately arranged.

[0056] In a battery string 110, an Nth battery cell, an (N+1)th battery cell, and an (N+2)th battery cell (N is a positive integer greater than 1) are arranged sequentially along a first direction. The positive terminal of the Nth battery cell is connected to the negative terminal of the (N+1)th battery cell via multiple first connecting ribbons 1221, and the positive terminal of the (N+1)th battery cell is connected to the negative terminal of the (N+2)th battery cell via multiple second connecting ribbons 1222. The (N+1)th battery cell is not a first battery cell 1111. When the (N+1)th battery cell is a first battery cell 1111, the positive terminal of the Nth battery cell is connected to the negative terminal of the (N+1)th battery cell via the first connecting ribbons 121. The middle portion of the first connecting ribbon 1221 overlaps with the busbar 130, and the end portion of the second connecting ribbon 1222 overlaps with the busbar 130.

[0057] The first spacing is the distance between the end of the orthographic projection of the first solder strip 121 and the end of the orthographic projection of the second connecting solder strip 1222. That is, along the thickness direction of the back contact solar cell 111, the first solder strip 121 and the second connecting solder strip 1222 do not overlap. Lamination is a crucial step in the production of the solar module 100. During lamination, a certain pressure is applied to the solar module 100. If the first solder strip 121 and the second connecting solder strip 1222 overlap without the first spacing, the pressure on the overlapping area will increase significantly. Since the back contact solar cell 111 is relatively fragile, excessive local pressure can easily lead to microcracks in the cell. By setting the first spacing, the first solder strip 121 and the second solder strip 122 will not overlap during lamination, allowing the pressure to be distributed more evenly on the cell, effectively reducing the risk of microcracks, improving the integrity and reliability of the cell, and thus increasing the overall yield of the solar module 100.

[0058] Furthermore, the length of the first spacing is 1–4 mm. Both the busbar 130 and the separator 140 have a certain thickness. During lamination, the busbar 130 and separator 140 will bend, and the back contact solar cell 111 will bear greater pressure during the stacking process. When the first spacing is less than 1 mm, the space between the first solder ribbon 121 and the second solder ribbon 122 is too small. When the busbar 130 and separator 140 bend, there is insufficient space, resulting in compression. This makes the cells in the busbar 130 area more prone to microcracks, reducing the yield and reliability of the battery module. When the first spacing is greater than 4 mm, the excessive spacing makes the connection between the solder ribbon 120 and the back contact solar cell 111 weak, reducing the structural strength of the battery module 100. Under external impact or vibration, the battery module 100 is more easily damaged, affecting its service life and reliability.

[0059] Example 4 In some embodiments, the axes of the orthographic projections of the first solder strip 121 and a portion of the second solder strip 122 are collinear. The second solder strip 122, with one end positioned below the busbar 130, is collinear with the first solder strip 121. This collinear design facilitates positioning and welding operations during production, improving production efficiency and product consistency. Simultaneously, it allows for smoother current transmission, reducing current segregation and loss. This contributes to improving the electrical performance of the battery module 100, enabling it to convert solar energy into electrical energy more efficiently and increasing power generation efficiency.

[0060] In some embodiments, the width of the first solder strip 121 and the width of the second solder strip 122 are the same. Selecting the first solder strip 121 and the second solder strip 122 with the same width ensures that their width tolerance is within a very small range (e.g., ±0.1 mm). The consistent width of the first solder strip 121 and the second solder strip 122 allows for consistent welding parameters (such as welding temperature and welding time) during the welding process, facilitating the control and optimization of the welding process. Simultaneously, the consistent width also makes the appearance of the battery module 100 more neat and aesthetically pleasing, improving the overall quality and consistency of the product. Furthermore, in terms of current transmission, solder strips 120 of the same width have similar resistance characteristics, which helps to ensure a uniform current distribution in the solder strips 120, reducing losses during current transmission and improving the electrical performance of the battery module 100.

[0061] Example 5 A photovoltaic system includes the aforementioned battery module 100.

[0062] Photovoltaic systems can be applied in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants. They can also be applied to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it'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 system grid as an example, a photovoltaic system can include photovoltaic arrays, combiner boxes, and inverters. The photovoltaic array can be an array combination of multiple battery modules 100. For example, multiple battery modules 100 can form multiple photovoltaic arrays. The photovoltaic arrays are connected to combiner boxes, which can 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 power grid before being connected to the mains power grid to achieve solar power supply.

[0063] The beneficial effects of the photovoltaic system in this embodiment are equivalent to the beneficial effects of the battery module 100 described above, and will not be repeated here.

[0064] The above description is only a preferred embodiment of the present utility model and is 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 battery assembly, characterized in that, include: Battery strings, solder strips, and busbars; The battery string includes a plurality of back-contact solar cells arranged in an overlapping manner along a first direction. Adjacent back-contact solar cells are connected in series by the solder strip. Each back-contact solar cell includes a first cell and a second cell arranged along the first direction. The solder strips extend along the first direction and are arranged on the back side of the back-contacting solar cell array, including a first solder strip and a second solder strip; The busbar is stacked on the edge of the second battery cell near the first battery cell and extends along the second direction, which intersects the second direction; the first solder strip is electrically connected to the busbar, and the second solder strip is insulated from the busbar; One end of the first solder strip is positioned above the busbar, and one end of a portion of the second solder strip is positioned below the busbar. Along the first direction, the length by which the orthographic projection of the first solder strip overlaps with the orthographic projection of the busbar is greater than the length by which the orthographic projection of a portion of the second solder strip overlaps with the orthographic projection of the busbar.

2. The battery assembly as described in claim 1, characterized in that, The length d1 of the overlap between the orthographic projection of the first solder strip and the orthographic projection of the busbar, and the length d2 of the overlap between the orthographic projection of the second solder strip and the orthographic projection of the busbar, are both less than 5 mm.

3. The battery assembly as described in claim 2, characterized in that, The length of d1 ranges from 3 to 8 mm.

4. The battery assembly as described in claim 2, characterized in that, The length of d2 ranges from 3 to 8 mm.

5. The battery assembly as claimed in claim 1, characterized in that, Along the first direction, a plurality of second welding strips are staggered; along the second direction, a plurality of second welding strips are staggered.

6. The battery assembly as claimed in claim 1, characterized in that, The axes of the orthographic projections of the first solder strip and a portion of the second solder strip are collinear.

7. The battery assembly as claimed in claim 1, characterized in that, It also includes a separation strip, which extends along a second direction, and the separation strip and the busbar are stacked together. The busbar and the isolation strip are disposed between the first solder strip and the second solder strip, with the first solder strip in contact with the busbar and the second solder strip in contact with the isolation strip.

8. The battery assembly as claimed in claim 1, characterized in that, One end of the first solder strip is positioned above the busbar, and one end of a portion of the second solder strip is positioned below the busbar. The orthographic projections of the first solder strip and the portion of the second solder strip have a first spacing along the first direction.

9. The battery assembly as claimed in claim 8, characterized in that, The length of the first spacing is 1 to 4 mm.

10. The battery assembly as claimed in claim 1, characterized in that, The width of the first solder strip is the same as the width of the second solder strip.

11. A photovoltaic system, characterized in that, Includes the battery assembly as described in any one of claims 1 to 10.

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