A battery piece, a battery string and a photovoltaic module

Abstract

This invention relates to the field of photovoltaic module technology, specifically to a solar cell, a solar cell string, and a photovoltaic module. The solar cell provided by this invention includes a substrate having a backlight surface. In this invention, each current collector grid line and the current collector electrode with opposite polarity are disconnected at the junction point, avoiding the need for printing insulating adhesive and solder paste required in traditional "through-grid design," thus reducing material costs and alleviating environmental pressure. Furthermore, the main grid section of the current collector electrode is divided into a first section without solder pads and a second section with solder pads. In the area where the main grid section of the current collector electrode contacts the solder strip, the first section eliminates the solder pads, and the solder strip does not form a welded connection in this section, but the main grid line body is still retained for current collection. The second section has solder pads to ensure a reliable connection with the solder strip. Compared to the existing open-grid design where the entire main grid line has solder pads, this reduces the amount of silver paste used and lowers manufacturing costs.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic module technology, specifically to a solar cell, a solar cell string, and a photovoltaic module. Background Technology

[0002] In the current development roadmap of crystalline silicon photovoltaic cells, back-contact cells will gradually replace bifacial contact cells as the next generation of mainstream products. The metal grid pattern design of BC cells has also generated new design requirements and application optimizations due to the structural characteristics of BC cells. Currently, there are generally two schemes for the metal grid pattern design of BC cells: one is the "through-grid design" where the fine grid runs through the entire cell. This design requires printing insulating adhesive at each intersection of the solder ribbon and the non-standard grid line, and printing solder paste at the intersection of the solder ribbon and the same-standard grid line. The other is the "broken-grid design" where the fine grid lines are broken at each non-standard main grid with a certain break distance. This design generally does not require printing solder paste in the module packaging process, "but its main grid lines are of equal width and have pad structures along the entire line."

[0003] The "through-grid design" scheme requires printing insulating adhesive and solder paste during the module assembly stage, which increases material costs and environmental pressures. Although the "broken grid design" scheme omits the need for solder paste, the overall silver paste consumption of the main grid lines increases significantly with the increase in the number of main grids, leading to higher manufacturing costs. Summary of the Invention

[0004] (i) The problem to be solved by the present invention is that the "through grid design" scheme requires printing insulating adhesive and solder paste during the component assembly stage, which increases material costs and environmental pressure; although the "broken grid design" scheme omits the need for solder paste, the overall silver paste consumption of the main grid line increases significantly with the increase in the number of main grids, and the manufacturing cost rises.

[0005] (II) Technical Solution The present invention provides a battery cell, comprising a substrate having a backlight surface; The backlight surface is provided with a plurality of bus electrodes arranged along a first direction, and also with a plurality of collector grid lines arranged along a second direction; Each of the aforementioned collector grid lines is disconnected from the bus electrode with opposite polarity at the junction point, and is continuous and electrically connected to the bus electrode with the same polarity at the junction point; Each of the bus electrodes includes a main gate segment, which includes a first segment without pads and a second segment with pads, wherein the first direction and the second direction intersect.

[0006] According to one embodiment of the present invention, the bus electrode further includes a main gateless segment, both ends of the main gateless segment are provided with the main gate segment, and the second segment of the bus electrode is provided between the main gateless segment and the first segment of the main gate segment; The gateless section contains multiple pads arranged sequentially along the second direction.

[0007] According to one embodiment of the present invention, the center distance between two adjacent collector grid lines is D; The length of the first segment in each of the main gate segments is 2D-6D; And / or, the length of the second segment in each of the main gate segments is 8D-24D.

[0008] According to one embodiment of the present invention, along the second direction, the substrate has a first edge and a second edge, the distance from the first edge to the second edge is L, the distance from the first edge to the adjacent collector grid line is M, the distance from the second edge to the adjacent collector grid line is N, and the length of the masterless gate segment of the bus electrode is between (L-60D-MN) and (L-20D-MN).

[0009] According to one embodiment of the present invention, the collector grid lines include first collector grid lines and second collector grid lines arranged alternately along a second direction; The bus electrode includes a second bus electrode and a first bus electrode arranged alternately along a first direction; The first collector grid line is of the same polarity as the first bus electrode and is electrically connected, and is disconnected at the junction with the second bus electrode; The second collector grid line is on the same pole and electrically connected to the second bus electrode, and is disconnected at the junction with the first bus electrode.

[0010] According to one embodiment of the present invention, the number of the first collector grid lines differs from the number of the second collector grid lines by one.

[0011] According to one embodiment of the present invention, the difference between the length of the main gate segment located in the first bus electrode and the length of the main gate segment located in the second bus electrode is less than or equal to 2D.

[0012] According to one embodiment of the present invention, the length of the main gate segment located in the first bus electrode is the same as the length of the main gate segment located in the second bus electrode.

[0013] A battery string comprising a plurality of any of the aforementioned battery cells, wherein the plurality of battery cells are connected in series along the second direction.

[0014] A photovoltaic module comprising any of the aforementioned cells or cell strings.

[0015] The beneficial effects of this invention are: Each collector grid line and the bus electrode with opposite polarity are disconnected at the junction point, avoiding the need for printing insulating glue and solder paste as required by the traditional "through-grid design". This reduces material costs and alleviates environmental pressure. Furthermore, the main grid section of the bus electrode is divided into a first section without pads and a second section with pads. In the area where the main grid section of the bus electrode contacts the solder strip, the first section eliminates the pads and the solder strip does not form a solder connection in this section, but the main grid line body is still retained for current collection. The second section has pads to ensure a reliable connection with the solder strip. Compared with the existing open-grid design where the main grid has pads along the entire line, this reduces the amount of silver paste used and lowers manufacturing costs.

[0016] The second section of the solder pads provides the necessary fixed support points for the solder strip. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a front view of a battery cell provided in an embodiment of the present invention; Figure 2 A front view of the first bus electrode provided in an embodiment of the present invention.

[0019] Icons: 1. First segment; 2. Second segment; 3. Substrate; 31. First edge; 32. Second edge; 4. First collector grid line; 5. Second collector grid line; 6. First bus electrode; 7. Second bus electrode; 8. No main gate segment; 9. Pad. Detailed Implementation

[0020] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1: like Figures 1-2 As shown, one embodiment of the present invention provides a battery cell, including a substrate 3, the substrate 3 having a backlight surface; The backlight surface is provided with multiple bus electrodes arranged along a first direction, and also with multiple collector grid lines arranged along a second direction; Each collector grid line is disconnected from the bus electrode with the opposite polarity at the junction point, and is continuous and electrically connected to the bus electrode with the same polarity at the junction point. Each bus electrode includes a main gate segment, which includes a first segment 1 without pads 9 and a second segment 2 with pads 9, with the first direction and the second direction intersecting.

[0022] In this application, each collector grid line and the bus electrode with opposite polarity are disconnected at the junction point, avoiding the need for printing insulating glue and solder paste as required by the traditional "through-grid design". This reduces material costs and alleviates environmental pressure. Furthermore, the main grid section of the bus electrode is divided into a first section 1 without pads 9 and a second section 2 with pads 9. In the area where the main grid section of the bus electrode contacts the solder strip, the first section 1 eliminates the setting of pads 9, and the solder strip does not form a solder connection in this section, but the main grid line body is still retained for current collection. The second section 2 is equipped with pads to ensure a reliable connection with the solder strip. Compared with the structure of the existing open-grid design where the main grid is equipped with pads 9 along the entire line, the amount of silver paste used is reduced, and the manufacturing cost is lowered.

[0023] The second section 2 provides the necessary fixed support points for the solder strip by setting the solder pad 9.

[0024] Specifically, the substrate 3 of the solar cell has a backlight surface, meaning that the substrate 3 is configured with electrodes arranged on the opposite side of the backlight surface as the light-receiving surface, suitable for a back-contact battery structure. On the backlight surface, multiple bus electrodes extend along a second direction, and multiple current collector grid lines extend along a first direction.

[0025] The first direction intersects with the second direction to form a cross-grid electrode collection layout, thereby effectively covering the backlight area of ​​the substrate 3.

[0026] In some embodiments, the angle between the first direction and the second direction is 90 degrees; that is, the first direction and the second direction are perpendicular to each other, allowing for a reasonable range of angular error, for example, the angle between the first direction and the second direction is 90 ± 5 degrees. Further, one of the first direction and the second direction is the length direction of the battery cell and the other is the width direction of the battery cell. That is, in some embodiments, the first direction is the length direction of the battery cell, and the second direction is the width direction of the battery cell; in other embodiments, the second direction is the length direction of the battery cell, and the first direction is the width direction of the battery cell; for embodiments where the battery cell is square, there is no strict distinction between length and width.

[0027] In some embodiments, the linewidth of the collector grid lines is configured to remain equal along their extension direction, or to gradually widen near the bus electrode, to reduce local resistance when current is injected into the bus electrode. Preferably, the linewidth of the collector grid lines ranges from 10 μm to 30 μm, and the center-to-center distance D between two adjacent collector grid lines ranges from 0.5 mm to 2.0 mm. This size range balances current collection capability and light-shielding area, while avoiding a significant increase in silver paste consumption due to overly dense grid line distribution. Further, the linewidth of the main grid segment of the bus electrode is configured to be greater than the linewidth of the collector grid lines to reduce resistance loss in the bus direction. Preferably, the linewidth of the main grid segment is 2-5 times the linewidth of the collector grid lines.

[0028] According to one embodiment of the present invention, the bus electrode further includes a main gateless segment 8, both ends of the main gateless segment 8 are provided with main gate segments, and the second segment 2 of the bus electrode is provided between the main gateless segment 8 and the first segment 1 of the main gate segment; The gateless section 8 contains multiple pads 9 arranged sequentially along the second direction.

[0029] Specifically, along the extension direction (second direction) of the bus electrode, the first segment 1, the second segment 2, the gridless segment 8, the second segment 2, and the first segment 1 are arranged in sequence to form a symmetrical segment arrangement structure. The coreless section 8 contains multiple pads 9 arranged sequentially along the second direction, appearing as dots within the coreless section 8. In the coreless section 8, since there are no continuous main grid lines, only the pads 9 are retained as current collection points and soldering points. While maintaining current collection capability, the amount of silver paste used in this area is significantly reduced, effectively lowering material costs. Simultaneously, these pads 9 can still form electrical contact with the solder strips laid upon them and provide auxiliary fixing during the lamination process.

[0030] In some embodiments, the spacing between two adjacent pads 9 in the non-main gate segment 8 of each bus electrode is equal to the center distance between two adjacent same polarity collector gate lines. The center distance between two adjacent same polarity collector gate lines is 2D, so that each pad 9 corresponds exactly to the end position of a same polarity collector gate line, thereby ensuring that the current collected by each collector gate line can be effectively collected through the corresponding pad 9, avoiding local current congestion caused by uneven distribution of pads 9.

[0031] In some embodiments, the shape of the pad 9 is configured as circular, harpoon-shaped, elliptical, or rectangular, and the area of ​​the pad 9 is configured as 0.04 mm²-0.10 mm². This area range ensures reliable soldering with the solder ribbon without wasting silver paste due to an excessively large pad 9, while also avoiding insufficient soldering strength caused by an excessively small pad 9.

[0032] Positioning the second segment 2 at the transition point between the busbarless segment 8 and the first segment 1 allows the solder strip to be reliably anchored during welding, improving the stability of the module encapsulation. The segmented busbar design allows for size and layout adjustments based on different cell types, enhancing practicality.

[0033] According to one embodiment of the present invention, the center distance between two adjacent collector grid lines is D; The length of the first segment 1 in each main grid segment is 2D-6D; And / or, the length of the second segment 2 in each main gate segment is 8D-24D.

[0034] The length of the first segment 1 in each main busbar segment is configured to be between 2D and 6D, meaning that the extension length of the first segment 1 is equivalent to the total spacing of 2 to 6 adjacent collector grid lines. Within this range, the first segment 1 can cover the collector grid lines located at the outermost edge of the cell, ensuring that the current collected by the collector grid lines at the edge has a transmission path into the main busbar segment. At the same time, since the first segment 1 does not have pads 9, its silver paste consumption is significantly lower than that of traditional main busbar designs with pads throughout the entire line.

[0035] In some embodiments, the length of the first segment 1 is adapted to the inward distance of the cut-off portion of the solder strip on the cell, that is, the length of the first segment 1 is equal to the inward distance between the end of the solder strip and the edge of the cell. The value of this inward distance is related to the thermal expansion coefficient of the solder strip and the lamination temperature in the module lamination process. Preferably, the inward distance is 2D-6D. Further, in the same busbar electrode, the two first segments 1 located at both ends of the busbarless segment 8 have equal lengths to ensure that the inward distances at both ends of the cell are consistent, so that the stress distribution of the solder strip at both ends is symmetrical.

[0036] In other embodiments, the lengths of the two first segments 1 located at both ends of the gridless segment 8 are not equal, in order to adapt to special packaging processes where the solder strip has different inward distance requirements at both ends of the cell. For example, when one end of the cell is the solder strip inlet end and the other end is the solder strip outlet end, the required inward distance at both ends can be set differently according to actual needs.

[0037] The length of the second segment 2 in each main grid segment is configured to be between 8D and 24D, meaning the extension length of the second segment 2 is equivalent to the total spacing of 8 to 24 adjacent collector grid lines. As the main welding segment, the second segment 2 is set relatively long to ensure sufficient welding contact area for the solder strip within this segment, thereby achieving reliable mechanical fixation and a low-contact-resistance electrical connection. The longer second segment 2 also provides multi-point support during the lamination process, preventing the solder strip from shifting or detaching under high temperature and pressure conditions. Setting the lower limit of the second segment 2 to 8D ensures that at least four collector grid lines' corresponding pads 9 can weld with the solder strip, meeting tensile strength requirements; setting the upper limit to 24D accommodates the welding needs of large-size cells while avoiding an excessively long second segment 2 that would increase silver paste usage.

[0038] Furthermore, the ratio of the length of the first segment 1 to the length of the second segment 2 is configured to be between 1:3 and 1:8. This ratio range ensures the reliability of the solder ribbon fixation while controlling the silver paste saving area within a reasonable proportion, avoiding affecting the welding quality or current transmission uniformity due to excessive removal of solder pad 9. This achieves the best balance between silver paste saving effect and welding reliability.

[0039] According to one embodiment of the present invention, along the second direction, the substrate 3 has a first edge 31 and a second edge 32, the distance from the first edge 31 to the second edge 32 is L, the distance from the first edge 31 to its adjacent collector grid line is M, the distance from the second edge 32 to its adjacent collector grid line is N, and the length of the non-main grid segment 8 of the bus electrode is between (L-60D-MN) and (L-20D-MN).

[0040] Along the second direction, the substrate 3 has a first edge 31 and a second edge 32, wherein the distance between the first edge 31 and the second edge 32 is defined as L, which represents the total span of the substrate 3 in the second direction. Meanwhile, the distance from the first edge 31 to its adjacent collector grid line is defined as M, and the distance from the second edge 32 to its adjacent collector grid line is defined as N. M and N are typically edge blank areas used for insulation isolation or process clamping.

[0041] The length of the masterless segment 8 of the first bus electrode 6 is between (L-60D-MN) and (L-20D-MN). D is the center-to-center distance between adjacent collector grid lines, so (LMN) represents the total effective collection width from the collector grid line closest to the first edge 31 to the collector grid line closest to the second edge 32, which includes multiple collector grid line spacings and is adapted to the length of the bus electrode.

[0042] Specifically, when the length of the busbarless segment 8 is at its minimum (L-60D-MN), the area occupied by the main busbar segment is larger, which is beneficial for setting a longer second segment 2 at both ends of the cell to enhance the welding strength of the solder strip ends. This is suitable for modules with large size or high reliability requirements. When the length of the busbarless segment 8 is at its maximum (L-20D-MN), the silver loss of the busbarless segment 8 is further reduced, but the main busbar segment is correspondingly shortened. This is suitable for scenarios with high welding process stability. By limiting this range, the silver paste distribution of the busbar electrode is made more reasonable, avoiding the weakening of the solder strip end fixing force due to the excessive length of the busbarless segment 8 at the edge area, or the inability to effectively reduce silver loss due to the excessively short busbarless segment 8.

[0043] Preferably, the distance M from the first edge 31 to the adjacent collector fine grid line and the distance N from the second edge 32 to the adjacent collector grid line are both equal to the distance D between two adjacent collector grid lines. In this case, the length of the non-main grid segment 8 of the first bus electrode 6 is between (L-62D) and (L-22D).

[0044] Preferably, the length of the non-main grid segment 8 in the bus electrode is the longest, the length of the second segment 2 of the main grid segment on one side is the second longest, and the length of the first segment 1 of the main grid segment on one side is the shortest. This length design can ensure the reliability of the solder ribbon fixation and significantly save the amount of silver paste used.

[0045] According to one embodiment of the present invention, the collector grid lines include a first collector grid line 4 and a second collector grid line 5 arranged alternately along a second direction; The bus electrode includes a second bus electrode 7 and a first bus electrode 6 arranged alternately along a first direction; The first collector grid line 4 is of the same polarity as the first bus electrode 6 and is electrically connected, and is disconnected at the junction with the second bus electrode 7; The second collector grid line 5 is electrically connected to the second bus electrode 7 and has the same polarity, but is disconnected at the junction with the first bus electrode 6.

[0046] Preferably, the first collector grid line 4 collects electrons and the second collector grid line 5 collects holes; In another embodiment, the first collector grid line 4 collects holes and the second collector grid line 5 collects electrons.

[0047] According to one embodiment of the present invention, the length of the main gate segment located in the first bus electrode 6 is the same as the length of the main gate segment located in the second bus electrode 7.

[0048] By setting the main grid segment lengths of the two types of bus electrodes to be the same, the silver paste consumption of the first bus electrode 6 and the second bus electrode 7 is kept equal, avoiding material consumption imbalances caused by different polarities. Simultaneously, the total length of the second segment 2 available for solder ribbon welding on both types of bus electrodes is also the same, resulting in the same number and distribution density of welding points for both positive and negative electrode solder ribbons on the solar cell. This promotes uniform stress on the solder ribbons during lamination and reduces the risk of warping or microcracks caused by differences in thermal expansion coefficients.

[0049] At the manufacturing level, the identical length of the main grid segments allows the printing screen to maintain a symmetrical pattern during design, reducing the complexity of screen production and calibration, and improving printing accuracy and consistency.

[0050] According to one embodiment of the present invention, the number of the first collector grid lines 4 differs from the number of the second collector grid lines 5 by one.

[0051] According to one embodiment of the present invention, the difference between the length of the main gate segment located in the first bus electrode 6 and the length of the main gate segment located in the second bus electrode 7 is less than or equal to 2D.

[0052] In some cell designs, the number of first collector grid lines 4 may be one more or one less than the number of second collector grid lines 5, resulting in a slight difference in the number of collector grid lines connected to the two polarity bus electrodes, which in turn causes a slight difference in the required main grid segment length. In this case, a deviation of ±2D can be allowed to accommodate this layout, without sacrificing the uniformity of the collector grid line distribution or wasting the length of the bus electrode in pursuit of perfectly consistent lengths.

[0053] Example 2: A battery string, including the battery cells in Example 1, wherein multiple battery cells are arranged along a first direction or a second direction, and adjacent battery cells are electrically connected by welding strips.

[0054] Specifically, multiple solar cells are arranged sequentially in the same direction. In each pair of adjacent cells, the current collectors of the preceding cell and the corresponding current collectors of opposite polarity in the following cell are connected in series via solder ribbons. Taking the first current collector 6 and the second current collector 7 as an example, they have opposite polarities. The first current collector 6 of the preceding cell is soldered to the second current collector 7 of the following cell via solder ribbons, while the second current collector 7 of the preceding cell is soldered to the first current collector 6 of the following cell via another solder ribbon, thus achieving series output of opposite polarities between the preceding and following cells. Since each solar cell's current collector electrode has a first segment 1 and a second segment 2, the solder ribbon is only soldered to the pad 9 at the second segment 2, and not to the current collector electrode at the first segment 1. This reduces the tensile stress on the edge of the cell caused by the shrinkage of the solder ribbon, and also eliminates the need for printing insulating adhesive, simplifying the encapsulation process.

[0055] Example 3: A photovoltaic module, comprising the solar cells of Example 1 or the solar cell strings of Example 2; Because on the back surface of the solar cell, the individual collector grid lines (first collector grid line 4 and second collector grid line 5) are disconnected at the junction with the opposite polarity bus electrode (first bus electrode 6 or second bus electrode 7), and are continuous and electrically connected with the same polarity bus electrode at the junction, during the photovoltaic module encapsulation process, the solder ribbon can be directly laid on top of the bus electrode along its extension direction without the need to print insulating adhesive for isolation at each junction of the solder ribbon and the opposite polarity collector grid line. This significantly simplifies the module encapsulation process and avoids the time cost required for the use of insulating adhesive materials and their curing process.

[0056] Because the main grid section of the busbar electrode is provided with a first section 1 (without pad 9) and a second section 2 (with pad 9), the solder strip is only soldered at the second section 2 during module encapsulation, and not at the first section 1. This allows the solder strip to have a certain amount of free space for thermal expansion in the subsequent lamination process, reducing the tensile stress on the edge of the cell caused by the shrinkage of the solder strip. This effectively reduces the lamination breakage rate and the risk of microcracks, and improves the production yield and long-term outdoor reliability of photovoltaic modules.

[0057] In the description of this invention, it should be noted that the terms "upper" and "lower," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention 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, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0058] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linkage" 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 or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A battery cell, comprising a substrate (3), characterized in that, The substrate (3) has a backlight surface; The backlight surface is provided with a plurality of bus electrodes arranged along a first direction, and also with a plurality of collector grid lines arranged along a second direction; Each of the aforementioned collector grid lines is disconnected from the bus electrode with opposite polarity at the junction point, and is continuous and electrically connected to the bus electrode with the same polarity at the junction point; Each of the bus electrodes includes a main gate segment, which includes a first segment (1) without pads (9) and a second segment (2) with pads (9), the first direction and the second direction intersecting.

2. The battery cell according to claim 1, characterized in that, The bus electrode also includes a main gateless segment (8), both ends of which are provided with the main gate segment, and the second segment (2) of the bus electrode is located between the main gateless segment (8) and the first segment (1) of the main gate segment; The gateless section (8) contains multiple pads (9) arranged sequentially along the second direction.

3. A battery cell according to claim 2, characterized in that, The center distance between two adjacent collector grid lines is D; The length of the first segment (1) in each of the main gate segments is 2D-6D; And / or, the length of the second segment (2) in each of the main gate segments is 8D-24D.

4. A battery cell according to claim 3, characterized in that, Along the second direction, the substrate (3) has a first edge (31) and a second edge (32), the distance from the first edge (31) to the second edge (32) is L, the distance from the first edge (31) to the adjacent collector grid line is M, the distance from the second edge (32) to the adjacent collector grid line is N, and the length of the masterless gate segment (8) of the bus electrode is between (L-60D-MN) and (L-20D-MN).

5. A battery cell according to claim 1, characterized in that, The collector grid lines include a first collector grid line (4) and a second collector grid line (5) arranged alternately along the second direction. The bus electrode includes a second bus electrode (7) and a first bus electrode (6) arranged alternately along a first direction. The first collector grid line (4) is on the same pole and electrically connected to the first bus electrode (6), and is disconnected at the junction with the second bus electrode (7); The second collector grid line (5) is on the same pole and electrically connected to the second bus electrode (7), and is disconnected at the junction with the first bus electrode (6).

6. A battery cell according to claim 5, characterized in that, The number of the first collector grid line (4) differs from the number of the second collector grid line (5) by 1.

7. A battery cell according to claim 5, characterized in that, The difference between the length of the main gate segment located in the first bus electrode (6) and the length of the main gate segment located in the second bus electrode (7) is less than or equal to 2D.

8. A battery cell according to claim 5, characterized in that, The length of the main gate segment located in the first bus electrode (6) is the same as the length of the main gate segment located in the second bus electrode (7).

9. A battery string, characterized in that, It includes multiple solar cells as described in any one of claims 1 to 8, wherein the multiple solar cells are connected in series along the second direction.

10. A photovoltaic module, characterized in that, Includes the battery cell as described in any one of claims 1 to 8 or the battery string as described in claim 9.

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