Main-grid-free back contact battery, battery assembly and photovoltaic system

Abstract

The utility model discloses a main-grid-free back contact cell, a cell assembly and a photovoltaic system, and belongs to the technical field of solar cells. The main-grid-free back contact battery comprises a battery piece body, fine grid lines, PAD points, an insulating layer and a solder paste layer, the plurality of fine grid lines are distributed at intervals along a first direction and are all arranged on the battery piece body; each fine grid line is provided with a PAD point, each PAD point comprises a welding point body and an extension part, and at least one end, in the second direction, of each welding point body is connected with the corresponding extension part; the insulating layer covers the extension part; the solder paste layer is arranged on the solder joint body and used for welding the solder strip to the solder joint body. According to the main-grid-free back contact battery, the extension part and the insulating layer are arranged, so that the length of the PAD point can be increased, the flowing range of the molten solder paste layer can be prolonged, and meanwhile, the flowing range of the molten solder paste can be limited, so that the phenomenon that the solder paste layer erodes the thin grid lines outside the PAD point area, and consequently the thin grid lines are broken is avoided.

Description

Technical Field

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

[0002] A solar cell (photovoltaic system) is a clean energy system that directly converts solar energy into electrical energy using the photovoltaic effect. A back-contact solar module (RCS) is a solar cell where the light-facing side of the cell has no electrodes; both the positive and negative electrodes are located on the back-facing side. This design reduces electrode shading of the cell, increases short-circuit current, and improves the cell's energy conversion efficiency. Specifically, gridless back-contact solar cells eliminate the traditional grid structure; the solder ribbon directly collects current through dense, fine grid lines, achieving current collection and interconnection between cells, reducing current loss, and achieving both increased efficiency and reduced cost.

[0003] like Figures 1-2 As shown, gridless back-contact solar cells in related technologies typically include a cell body 100', fine grid lines 200', PAD points 300', and solder paste 500'. In actual printing, to save on silver paste usage, PAD points 300' are usually elongated rectangles, and solder paste 500' is an ellipse with its major axis approximately equal to the length of PAD points 300', completely contained within the PAD point 300' area. However, when PAD points 300' are soldered to the solder ribbon, the solder paste 500' melts and flows outside the PAD point 300' area. This causes the fine grid lines 200' located outside the PAD point 300' area to be eroded by the solder paste 500' and prone to detachment, leading to grid breakage and other abnormalities, affecting the power and reliability of the solar module.

[0004] Therefore, there is an urgent need for a gridless back-contact cell, cell module, and photovoltaic system to solve the above problems. Utility Model Content

[0005] The purpose of this invention is to provide a gridless back contact cell, cell module and photovoltaic system, which can avoid the fine grid lines located outside the PAD point area from being eroded by the molten solder paste and falling off during soldering, thereby ensuring the quality and reliability of the finished product.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A gridless back contact battery, comprising:

[0008] The battery cell itself;

[0009] Fine grid lines, wherein a plurality of the fine grid lines are spaced apart along a first direction and are all disposed on the battery cell body;

[0010] PAD points are provided on each of the fine grid lines. Each PAD point includes a solder joint body and an extension. The extension is connected to at least one end of the solder joint body along the second direction.

[0011] An insulating layer covers the extension;

[0012] A solder paste layer is disposed on the solder joint body, and the solder paste layer is used to solder the solder strip to the solder joint body.

[0013] As a preferred embodiment of the gridless back contact battery provided by this utility model, the outer contour of the solder joint body is polygonal.

[0014] As a preferred embodiment of the gridless back contact battery provided by this utility model, the outer contour of the solder joint body is rectangular, and the outer contour of the extension is semi-circular or polygonal.

[0015] As a preferred embodiment of the gridless back contact battery provided by this utility model, the outer contour of the extension is rectangular or trapezoidal.

[0016] As a preferred embodiment of the gridless back contact battery provided by this utility model, when the outer contour of the extension is rectangular, the width of the extension is equal to or unequal to the width of the solder joint body.

[0017] As a preferred embodiment of the gridless back contact battery provided by this utility model, when the outer contour of the extension is trapezoidal, the extension includes a first side and a second side that are parallel to each other, and the first side is connected to the solder joint body.

[0018] As a preferred embodiment of the gridless back contact battery provided by this utility model, the outer contour of the extension is triangular, and one side of the extension of the triangle is connected to the solder joint body.

[0019] As a preferred embodiment of the gridless back contact battery provided by this utility model, the extension is T-shaped or cross-shaped.

[0020] As a preferred embodiment of the gridless back contact battery provided by this utility model, the outer contour of the solder paste layer is elliptical.

[0021] As a preferred embodiment of the gridless back contact battery provided by this utility model, at least one side of the solder joint body is tangent to the outer contour of the solder paste layer.

[0022] As a preferred embodiment of the gridless back contact battery provided by this utility model, each of the fine grid lines is provided with a plurality of PAD points, and the plurality of PAD points are arranged at intervals along the length direction of the corresponding fine grid line.

[0023] This utility model also provides a battery assembly, including a plurality of gridless back contact batteries as described above.

[0024] This invention also provides a photovoltaic system, including the battery assembly described above.

[0025] The beneficial effects of this utility model are as follows:

[0026] The gridless back contact battery provided by this utility model increases the length of the entire PAD point by providing an extension at the end of the solder joint body, thereby extending the flow range of the molten solder paste layer. This increases the printing offset process window and prevents the solder paste layer from eroding the fine grid lines located outside the PAD point area, thus avoiding grid breakage and ensuring the quality of the finished battery. By providing an insulating layer on the extension, the flow range of the molten solder paste can be limited, further preventing the solder paste from eroding the fine grid lines located outside the PAD point area. In addition, providing the insulating layer on the extension facilitates the installation of the insulating layer and reduces the processing precision and difficulty.

[0027] The battery module provided by this utility model, by applying the above-mentioned gridless back contact battery, can avoid the situation where the fine grid lines located outside the PAD point area are eroded by the molten solder paste and fall off during soldering, thereby ensuring the quality and reliability of the finished battery module.

[0028] The photovoltaic system provided by this utility model can improve the quality and reliability of the finished photovoltaic system by applying the above-mentioned battery components. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of this utility model and these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of a gridless back contact battery provided by related technologies;

[0031] Figure 2 This is a partial structural diagram of the fine grid lines, PAD points, and solder paste of a gridless back contact battery provided by related technologies;

[0032] Figure 3 This is a schematic diagram of the structure of the gridless back contact battery provided in Embodiment 1 of this utility model;

[0033] Figure 4 This is a partial structural diagram of the fine grid lines, PAD points, solder paste layer and insulating layer of the gridless back contact battery provided in Embodiment 1 of this utility model;

[0034] Figure 5 This is one of the structural schematic diagrams of the PAD points and solder paste layer of the gridless back contact battery provided in Embodiment 1 of this utility model;

[0035] Figure 6 This is the second schematic diagram of the structure of the PAD point and solder paste layer of the gridless back contact battery provided in Embodiment 1 of this utility model;

[0036] Figure 7 This is the third schematic diagram of the structure of the PAD point and solder paste layer of the gridless back contact battery provided in Embodiment 1 of this utility model;

[0037] Figure 8 This is the fourth schematic diagram of the structure of the PAD point and solder paste layer of the gridless back contact battery provided in Embodiment 1 of this utility model;

[0038] Figure 9 This is the fifth schematic diagram of the structure of the PAD point and solder paste layer of the gridless back contact battery provided in Embodiment 1 of this utility model;

[0039] Figure 10 This is the sixth schematic diagram of the structure of the PAD point and solder paste layer of the gridless back contact battery provided in Embodiment 1 of this utility model;

[0040] Figure 11 This is a schematic diagram of the structure of the PAD point and solder paste layer of the gridless back contact battery provided in Embodiment 2 of this utility model;

[0041] Figure 12 This is a schematic diagram of the structure of the PAD point and solder paste layer of the gridless back contact battery provided in Embodiment 3 of this utility model;

[0042] Figure 13 This is a schematic diagram of the structure of the PAD point and solder paste layer of the gridless back contact battery provided in Embodiment 4 of this utility model;

[0043] Figure 14 This is a schematic diagram of the structure of the PAD point and solder paste layer of the gridless back contact battery provided in Embodiment 5 of this utility model.

[0044] Figure label:

[0045] 100', Cell body; 200', Fine grid lines; 300', PAD points; 500', Solder paste;

[0046] 100. Solar cell body; 200. Fine grid lines;

[0047] 300. PAD point; 301. Solder joint body; 302. Extension; 3021. First side; 3022. Second side; 3023. Horizontal side; 3024. Vertical side;

[0048] 400, Insulating layer; 500, Solder paste layer. Detailed Implementation

[0049] Before explaining any embodiment of the present invention in detail, it should be understood that the present invention is not limited to its application to the structural details and component arrangements set forth in the following description or shown in the above drawings.

[0050] In this invention, the terms "comprising," "including," "having," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0051] In this invention, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, in this invention, the character " / " generally indicates that the preceding and following related objects have an "and / or" relationship.

[0052] In this invention, the terms "connection," "combination," "coupling," and "installation" can refer to direct connection, combination, coupling, or installation, or indirect connection, combination, coupling, or installation. For example, a direct connection refers to two parts or components being connected together without the need for an intermediary, while an indirect connection refers to two parts or components each being connected to at least one intermediary, with the connection achieved through the intermediary. Furthermore, "connection" and "coupling" are not limited to physical or mechanical connections or couplings, but can also include electrical connections or couplings.

[0053] In this invention, those skilled in the art will understand that relative terms (e.g., “about,” “approximately,” “basically,” etc.) used in conjunction with quantities or conditions are to include the value and have the meaning indicated by the context. For example, such relative terms include at least the degree of error associated with the measurement of a particular value, tolerances associated with the particular value due to manufacturing, assembly, use, etc. Such terms should also be considered as disclosing a range defined by the absolute values ​​of the two endpoints. Relative terms may refer to a certain percentage (e.g., 1%, 5%, 10% or more) of the indicated value. Numerical values ​​not using relative terms should also be disclosed as specific values ​​with tolerances. Furthermore, “basically” when expressing relative angular relationships (e.g., substantially parallel, substantially perpendicular) may refer to a certain degree (e.g., 1 degree, 5 degrees, 10 degrees or more) added to or subtracted from the indicated angle.

[0054] In this invention, those skilled in the art will understand that the function performed by a component can be performed by one component, multiple components, one part, or multiple parts. Similarly, the function performed by a part can be performed by one part, one component, or a combination of multiple parts.

[0055] In this utility model, the directional terms "upper," "lower," "left," "right," "front," and "rear" are used to describe the orientation and positional relationships shown in the accompanying drawings and should not be construed as limiting the embodiments of this utility model. Furthermore, in the context, it should be understood that when one element is mentioned as being connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected through an intermediate element. It should also be understood that directional terms such as upper side, lower side, left side, right side, front side, and rear side not only represent the direct orientation but can also be understood as the lateral orientation. For example, "below" can include directly below, lower left, lower right, lower front, and lower rear.

[0056] Example 1

[0057] Figure 3 A schematic diagram of the structure of the gridless back contact battery provided in this embodiment is shown. Figure 3 As shown, this embodiment provides a gridless back-contact solar cell, which includes a cell body 100, fine grid lines 200, and PAD points 300. Multiple fine grid lines 200 are spaced apart along a first direction and are all disposed on the cell body 100. Each fine grid line 200 is provided with a PAD point 300, which is used for welding to a solder strip (not shown in the figure). The cell body 100 is made of silicon wafer and is used to convert solar energy into electrical energy. The cell body 100 has a rectangular flat plate structure. Figure 3 The first direction shown is the length direction of the battery cell body 100. Figure 3 The second direction shown is the width direction of the cell body 100. The fine grid lines 200 serve to conduct the circuit. The fine grid lines 200 are formed on the back side of the cell body 100 by silver paste printing to reduce the shading of the electrodes on the cell, increase the short-circuit current of the cell, and improve the energy conversion efficiency of the cell.

[0058] Figure 4 This diagram shows a partial structural schematic of the fine grid line 200, PAD point 300, solder paste layer 500, and insulating layer 400 of the gridless back contact battery provided in this embodiment. Figure 5 This diagram illustrates one of the structural schematics of the PAD point 300 and solder paste layer 500 of the gridless back contact battery provided in this embodiment. Figures 4-5 and combined Figure 3 As shown, the PAD point 300 includes a solder joint body 301 and an extension 302. The extension 302 is connected to at least one end of the solder joint body 301 along the second direction. An insulating layer 400 covers the extension 302. A solder paste layer 500 is disposed on the solder joint body 301 and is used to solder the solder strip to the solder joint body 301. By providing an extension 302 at the end of the solder joint body 301, the length of the entire PAD point 300 can be increased, thereby extending the flow range of the molten solder paste layer 500. This increases the printing offset process window and prevents the solder paste layer 500 from eroding the fine grid lines 200 located outside the PAD point 300 area, thus preventing grid breakage and ensuring the quality of the finished battery. By providing an insulating layer 400 on the extension 302, the flow range of the molten solder paste can be limited, further preventing the solder paste from eroding the fine grid lines 200 located outside the PAD point 300 area. In addition, providing the insulating layer 400 on the extension 302 facilitates the installation of the insulating layer 400 and reduces processing accuracy and difficulty.

[0059] It should be explained that by directly connecting the fine grid line 200 to the solder strip through the PAD point 300, compared with the structure in the prior art where the main grid line and the fine grid line intersect perpendicularly, the setting of the main grid line is eliminated, which helps to reduce the consumption of grid line material silver paste, thereby significantly reducing material costs.

[0060] Specifically, such as Figure 4 and Figure 5 As shown, the outer contour of the solder joint body 301 is polygonal. The polygonal shape of the solder joint body 301 has two advantages: firstly, its relatively regular geometry facilitates processing and printing, which is beneficial for mass production; secondly, it helps to disperse the stress generated during the soldering process, preventing stress concentration that could lead to cracks or breakage of the PAD point 300, and also allows for uniform current distribution, reducing localized overheating. Optionally, the outer contour of the extension 302 is also polygonal, resulting in a simple structure that is easy to process and print.

[0061] In some embodiments, the outer contour of the solder joint body 301 is rectangular; the outer contour of the extension 302 is also rectangular. To facilitate silver paste printing, the width of the extension 302 is equal to the width of the solder joint body 301. That is, the PAD point 300 is a rectangular structure as a whole. Compared with the PAD points in the prior art, the length of the PAD point 300 in this embodiment is longer, which can increase the printing range of the solder paste layer 500 and the flow range of the molten solder paste, increase the printing offset process window, and at the same time avoid the molten solder paste from eroding the fine grid lines 200 located outside the PAD point 300 area, thereby preventing the fine grid lines 200 from breaking, thus ensuring the reliability of the gridless back contact battery.

[0062] It should be explained that the "length" mentioned above specifically refers to the dimension of the corresponding structure in the second direction; the "width" mentioned above specifically refers to the dimension of the corresponding structure in the first direction.

[0063] Figure 6 This is the second schematic diagram of the structure of the PAD point 300 and solder paste layer 500 of the gridless back contact battery provided in this embodiment. Figure 7 This is shown as the third schematic diagram of the structure of the PAD point 300 and solder paste layer 500 of the gridless back contact battery provided in this embodiment. Figures 6-7 As shown, in some embodiments, the width of the extension 302 may not be equal to the width of the solder joint body 301. For example, the width of the extension 302 may be set to be smaller than the width of the solder joint body 301 (e.g., ...). Figure 6 (as shown); or the width of the extension 302 can also be set to be greater than the width of the solder joint body 301 (as shown). Figure 7 (As shown).

[0064] Figure 8 The fourth schematic diagram shows the structure of the PAD point 300 and solder paste layer 500 of the gridless back contact battery provided in this embodiment. Figure 9 This is shown as the fifth schematic diagram of the structure of the PAD point 300 and solder paste layer 500 of the gridless back contact battery provided in this embodiment. Figures 8-9 As shown, in this embodiment, the outer contour of the solder joint body 301 is rectangular; the outer contour of the extension 302 is trapezoidal.

[0065] Specifically, the extension 302 includes a first side 3021 and a second side 3022 that are parallel to each other. The length of the first side 3021 is equal to the width of the solder joint body 301, and the first side 3021 is connected to the solder joint body 301 to facilitate silver paste printing and improve printing efficiency. Optionally, the length of the first side 3021 can be greater than the length of the second side 3022 (e.g., ...). Figure 8 (As shown); the length of the first side 3021 can also be less than the length of the second side 3022 (as shown). Figure 9As shown in the figure, this embodiment does not limit this aspect. Compared to Figure 9 The proposed solution Figure 8 The design of the extension 302 in the middle can reduce the amount of silver paste used to a certain extent, thereby reducing the processing cost of the gridless back contact battery.

[0066] Of course, in other embodiments, the side length of the first side 3021 can also be set to be different from the width of the solder joint body 301, that is, the side length of the first side 3021 is greater than the width of the solder joint body 301 or the side length of the first side 3021 is less than the width of the solder joint body 301. This setting can also achieve the above effect.

[0067] Figure 10 This is shown as diagram six of the structural schematics of the PAD point 300 and solder paste layer 500 of the gridless back contact battery provided in this embodiment. Figure 10 As shown, in this embodiment, the outer contour of the solder joint body 301 is rectangular; the outer contour of the extension 302 is triangular. Specifically, one side of the triangular extension 302 is connected to the solder joint body 301, and the length of this side is equal to the width of the solder joint body 301. Compared to rectangular or trapezoidal extensions 302, the triangular extension 302 has a smaller area, which can further reduce the amount of silver paste used, thereby reducing the processing cost of the gridless back contact battery.

[0068] It is understood that in other embodiments, the extension 302 may also be other shapes, such as pentagons, hexagons, etc., which will not be described in detail in this embodiment.

[0069] like Figures 4-10 As shown, in this embodiment, the outer contour of the solder paste layer 500 is elliptical. Specifically, the major axis of the elliptical solder paste layer 500 can be slightly smaller than the length of the solder joint body 301, and the minor axis of the elliptical solder paste layer 500 can be slightly smaller than the width of the solder joint body 301, in order to maximize the area of ​​the elliptical solder paste layer 500, thereby increasing the contact area between the solder paste layer 500 and the solder ribbon, and improving the soldering strength between them. This embodiment does not limit the minimum distance between the outer peripheral edge of the solder paste layer 500 and the edge of the solder joint body 301; the operator can adjust it according to actual printing needs, and this is not limited here.

[0070] Of course, in other embodiments, the outer contour of the solder paste layer 500 can also be a circle or other irregular shape, and this design can also achieve the above effect.

[0071] Continue as Figure 3As shown, each fine grid line 200 is provided with multiple PAD points 300, and the multiple PAD points 300 are arranged at intervals along the length direction of the corresponding fine grid line 200. By providing multiple PAD points 300 on each fine grid line 200, it is beneficial to shorten the current path and improve the energy conversion efficiency of the entire gridless back contact battery. In this embodiment, the specific number of PAD points 300 provided on each fine grid line 200 is not limited. Designers can adaptively adjust the specific number of PAD points 300 provided on each fine grid line 200 according to the length of the fine grid line 200 and the size of the battery cell body 100, etc., which is not limited here.

[0072] Example 2

[0073] This embodiment provides a gridless back contact battery. The specific structure of the gridless back contact battery is roughly the same as that of the gridless back contact battery provided in Embodiment 1. The difference is that the external contour shape of the extension 302 is different.

[0074] Figure 11 This diagram illustrates the structure of the PAD point 300 and solder paste layer 500 of the gridless back contact battery provided in this embodiment. Figure 11 As shown, in this embodiment, the outer contour of the solder joint body 301 is rectangular; the outer contour of the extension 302 is semi-circular. The straight edge of the semi-circular extension 302 is connected to the solder joint body 301, and the side length of the straight edge is equal to the width of the solder joint body 301, so as to facilitate processing and printing.

[0075] Example 3

[0076] This embodiment provides a gridless back contact battery. The specific structure of the gridless back contact battery is roughly the same as that of the gridless back contact battery provided in Embodiment 1. The difference is that the external contour shape of the extension 302 is different.

[0077] Figure 12 This diagram illustrates the structure of the PAD point 300 and solder paste layer 500 of the gridless back contact battery provided in this embodiment. Figure 12 As shown, in this embodiment, the outer contour of the extension 302 is T-shaped. Specifically, the extension 302 includes a horizontal side 3023 and a vertical side 3024 that are perpendicular to each other. One end of the vertical side 3024 is connected to the solder joint body 301, and the other end of the vertical side 3024 is connected to the horizontal side 3023. The T-shaped extension 302 can improve the contact strength between the fine gate line 200 and the PAD point 300, reduce the open circuit caused by printing misalignment, and at the same time increase the flow range of the molten solder paste, preventing the molten solder paste from eroding the fine gate line 200 located outside the PAD point 300 area, thus preventing the fine gate line 200 from breaking, thereby ensuring the reliability of the back contact battery without a main gate.

[0078] Compared to the extension 302 in Embodiment 1 and Embodiment 2, the T-shaped extension 302 has a smaller amount of silver paste, which can further reduce the amount of silver paste while extending the flow range after the solder paste layer 500 melts, thereby reducing the processing cost of the gridless back contact battery.

[0079] Example 4

[0080] This embodiment provides a gridless back contact battery. The specific structure of the gridless back contact battery is roughly the same as that of the gridless back contact battery provided in Embodiment 3. The difference is that the external contour shape of the extension 302 is different.

[0081] Figure 13 This diagram illustrates the structure of the PAD point 300 and solder paste layer 500 of the gridless back contact battery provided in this embodiment. Figure 13 As shown, in this embodiment, the outer contour of the extension 302 is cross-shaped. Specifically, the extension 302 includes a horizontal side 3023 and a vertical side 3024 that are perpendicular and intersecting each other, with one end of the vertical side 3024 connected to the solder joint body 301. The cross-shaped extension 302 can improve the contact strength between the fine gate line 200 and the PAD point 300, reduce the open circuit caused by printing misalignment, and at the same time increase the flow range of the molten solder paste, preventing the molten solder paste from eroding the fine gate line 200 located outside the PAD point 300 area, thus preventing the fine gate line 200 from breaking, thereby ensuring the reliability of the back contact battery without a main gate.

[0082] Compared to the extension 302 in Embodiment 3, the cross-shaped extension 302 can extend the flow range after the solder paste layer 500 melts, and further reduce the amount of silver paste used, while reducing the printing accuracy of the extension 302 and improving the printing efficiency.

[0083] Example 5

[0084] This embodiment provides a gridless back contact battery. The specific structure of the gridless back contact battery is roughly the same as that of the gridless back contact battery provided in Embodiment 3. The difference is that the external contour shape of the solder joint body 301 is different.

[0085] Figure 14 This diagram illustrates the structure of the PAD point 300 and solder paste layer 500 of the gridless back contact battery provided in this embodiment. Figure 14 As shown, in this embodiment, the outer contour of the solder joint body 301 is polygonal, and at least one side of the solder joint body 301 is tangent to the outer contour of the solder paste layer 500. This arrangement reduces the amount of silver paste used in the solder joint body 301, thereby further reducing the processing cost of the gridless back contact battery. For example, as... Figure 14 As shown, the solder joint body 301 is octagonal, and each side of the solder joint body 301 is tangent to the outer contour of the elliptical solder paste layer 500. Of course, this embodiment does not limit the specific shape of the solder joint body 301 or the number of sides tangent to the outer contour of the elliptical solder paste layer 500. Designers can make adaptive adjustments according to actual processing requirements.

[0086] It should be noted that this embodiment does not limit the shape of the outer contour of the extension 302. It can adopt any shape of the extension 302 in the above embodiments, and is not limited here.

[0087] Example 6

[0088] This embodiment provides a battery assembly comprising a plurality of battery strings, each battery string comprising a plurality of gridless back-contact cells. In this embodiment, the plurality of gridless back-contact cells in each battery string can be sequentially connected together by solder strips to form a battery string; the plurality of battery strings can be connected in series, in parallel, or in a series-parallel combination to achieve current bus output. For example, busbars can be used to connect the various battery strings.

[0089] The gridless back contact battery can be any of the methods described in the above embodiments. By using the gridless back contact battery described above, the battery module can avoid the fine grid lines 200 located outside the PAD point 300 area from being eroded by molten solder paste and falling off during soldering, thereby ensuring the quality and reliability of the finished battery module.

[0090] Example 7

[0091] This embodiment provides a photovoltaic system including a battery module, wherein the battery module can be the one provided in Embodiment Six. By applying the above-described battery module, the quality and reliability of the finished photovoltaic system can be improved.

[0092] Specifically, this photovoltaic system can be applied to photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants; it can also be applied to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. It is understood that the application scenarios of photovoltaic systems are not limited to the above scope; they can also be applied to all other fields that require solar energy for power generation.

[0093] Taking a photovoltaic power generation system grid as an example, the photovoltaic system includes a combiner box, an inverter, and a photovoltaic array composed of multiple battery modules. The photovoltaic array is connected to the combiner box, which can combine the current generated by the photovoltaic array. The combined current flows through the inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to realize solar power supply.

[0094] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that the above embodiments do not limit this utility model in any way, and all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of this utility model.

Claims

1. A back contact cell with no busbars, characterized in that, include: Battery cell body (100); Fine grid lines (200), a plurality of fine grid lines (200) are spaced apart along a first direction and are all disposed on the battery cell body (100); PAD point (300), each of the fine grid lines (200) is provided with a PAD point (300), the PAD point (300) includes a solder joint body (301) and an extension (302), the solder joint body (301) is connected to the extension (302) at least one end along the second direction; An insulating layer (400) covers the extension (302); A solder paste layer (500) is disposed on the solder joint body (301), and the solder paste layer (500) is used to solder the solder strip to the solder joint body (301).

2. The no-lead back-contact cell of claim 1, wherein, The outer contour of the solder joint body (301) is polygonal.

3. The eni -main grid back contact cell of claim 2, wherein, The outer contour of the solder joint body (301) is rectangular, and the outer contour of the extension (302) is semi-circular or polygonal.

4. The eni -main grid back contact cell of claim 3, wherein, The outer contour of the extension (302) is rectangular or trapezoidal.

5. The eni -main grid back contact cell of claim 4, wherein, When the outer contour of the extension (302) is rectangular, the width of the extension (302) is equal to or different from the width of the solder joint body (301).

6. The gridless back contact battery according to claim 4, characterized in that, When the outer contour of the extension (302) is trapezoidal, the extension (302) includes a first side (3021) and a second side (3022) that are parallel to each other, and the first side (3021) is connected to the solder joint body (301).

7. The no-lead back-contact cell of claim 3, wherein, The outer contour of the extension (302) is triangular, and one side of the triangular extension (302) is connected to the solder joint body (301).

8. The gridless back contact cell of claim 2, wherein, The outer contour of the solder paste layer (500) is elliptical.

9. The eni -main grid back contact cell of claim 8, wherein, At least one side of the solder joint body (301) is tangent to the outer contour of the solder paste layer (500).

10. The gridless back contact cell of claim 1, wherein, The extension (302) is T-shaped or cross-shaped.

11. The no-finger back-contact cell according to any one of claims 1 to 10, characterized in that, Each of the fine grid lines (200) is provided with a plurality of PAD points (300), and the plurality of PAD points (300) are arranged at intervals along the length direction of the corresponding fine grid line (200).

12. A battery assembly characterized by, It includes several gridless back contact batteries as described in any one of claims 1 to 11.

13. A photovoltaic system characterized by, Includes the battery assembly as described in claim 12.

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