Photovoltaic cell piece, photovoltaic cell string and photovoltaic module

Abstract

The utility model provides a photovoltaic cell sheet, a photovoltaic cell string and a photovoltaic assembly, and relates to the field of photovoltaic technology. An electric connection structure is formed on the first surface of the photovoltaic cell, the electric connection structure comprises a plurality of first grid lines, a plurality of second grid lines and a plurality of third grid lines which are arranged along a first direction and a plurality of connection lines which are arranged along a second direction, and the first direction is perpendicular to the second direction; the first surface is provided with a first area, a second area and a third area located between the first area and the second area, the first grid lines are arranged in the first area, the second grid lines are arranged in the second area, and the third grid lines are arranged in the third area; the distribution density of the plurality of first grid lines is greater than that of the plurality of second grid lines; the width of the third grid line is greater than that of the second grid line; and each connecting line is connected with each first grid line and each third grid line and extends towards the direction close to the second grid line. The photovoltaic cell is high in photoelectric conversion efficiency and low in cost.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaics, and in particular to a photovoltaic cell sheet, a photovoltaic cell string, and a photovoltaic module. Background Art

[0002] The statements in this section merely provide background technology related to the present invention and do not necessarily constitute prior art.

[0003] The grid lines of photovoltaic cells are a crucial component of the cell, collecting photogenerated carriers on the cell surface and transferring them to the exterior. The grid line design is closely related to the cell's photoelectric conversion efficiency. Grid line design requires consideration of multiple factors, including grid line width, spacing, material, and contact resistance with the cell surface.

[0004] During the metallization process of photovoltaic cells, silver paste is the main component of the grid lines. The goal is to reduce silver consumption without affecting cell efficiency. By optimizing the grid line design, power loss can be reduced and the photovoltaic conversion efficiency can be improved. Utility Model Content

[0005] The purpose of the present invention is to provide a photovoltaic cell, a photovoltaic cell string, and a photovoltaic module to solve the technical problem that it is difficult to improve the photoelectric conversion efficiency of photovoltaic cells.

[0006] In order to achieve the above purpose, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a photovoltaic cell, wherein an electrical connection structure is formed on a first surface of the photovoltaic cell, wherein the electrical connection structure includes a plurality of first grid lines, a plurality of second grid lines, a plurality of third grid lines arranged along a first direction, and a plurality of connection lines arranged along a second direction, wherein the first direction is perpendicular to the second direction;

[0008] The first surface has a first area, a second area and a third area located between the first area and the second area, the plurality of first gate lines are arranged in the first area, the plurality of second gate lines are arranged in the second area, and the plurality of third gate lines are arranged in the third area;

[0009] The distribution density of the plurality of first gate lines is greater than the distribution density of the plurality of second gate lines;

[0010] The width of the third gate line is greater than the width of the second gate line;

[0011] Each of the connecting lines is connected to each of the first gate lines and each of the third gate lines and extends toward the second gate line.

[0012] According to at least one embodiment of the present utility model, the electrical connection structure further includes at least one fourth gate line, the at least one fourth gate line is connected to at least one connecting line and is located in the third area;

[0013] The fourth gate line extends along the first direction.

[0014] According to at least one embodiment of the present invention, the width and height of the fourth gate line are respectively consistent with the width and height of the second gate line.

[0015] According to at least one embodiment of the present invention, the area ratio of the first region to the first surface is 1:(2-4).

[0016] According to at least one embodiment of the present invention, the ratio of the number of the first gate lines to the number of the second gate lines ranges from 2 to 3.

[0017] According to at least one embodiment of the present invention, the ratio of the width of the third gate line to the width of the second gate line is in the range of 1.5 to 2.5; and / or,

[0018] The height of the third gate line is consistent with the height of the second gate line.

[0019] According to at least one embodiment of the present invention, the material of the first gate line is silver-clad copper or electroplated copper; and / or,

[0020] The second gate line and the third gate line are made of silver.

[0021] According to at least one embodiment of the present invention, the photovoltaic cell has a second surface opposite to the first surface, and the electrical connection structure is formed on the second surface; and / or,

[0022] The first area on the first surface is opposite to the second area on the second surface, and the second area on the first surface is opposite to the first area on the second surface.

[0023] In a second aspect, the present invention provides a photovoltaic cell string, comprising a plurality of photovoltaic cells and a plurality of welding ribbons arranged along the second direction, wherein the plurality of photovoltaic cells are electrically connected through the plurality of welding ribbons, and at least one of the photovoltaic cells is the photovoltaic cell described in the first aspect;

[0024] Each of the welding strips is connected to each of the second gate lines and each of the third gate lines and extends toward the first gate lines.

[0025] In a third aspect, the present invention provides a photovoltaic assembly comprising the photovoltaic cell string described in the second aspect.

[0026] One or more technical solutions provided in the exemplary embodiments of the present invention can achieve at least one of the following beneficial effects.

[0027] The photovoltaic cell of the exemplary embodiment of the present utility model is formed with an electrical connection structure on the first surface, and the electrical connection structure forms a dense grid structure with multiple first grid lines arranged on the first area of ​​the first surface (the distribution density of the first grid lines is greater than the distribution density of the second grid lines), and forms a sparse grid structure with multiple second grid lines arranged on the second area (the distribution density of the second grid lines is smaller than the distribution density of the first grid lines), and at the same time forms multiple third grid lines on the third area (intersection area) located between the first area and the second area. Specifically, the first grid lines, the second grid lines and the third grid lines all extend along the second direction. Exemplarily, the three are arranged in parallel, the width of the third grid line is greater than the width of the second grid line, and the width of the second grid line is greater than the width of the second grid line. Each connecting line extends along the first direction across each first grid line and forms an electrical connection therewith, and each connecting line spans each third grid line in the third area and forms an electrical connection therewith. Compared with the prior art, in which only a sparse grid structure is used on the first surface of the cell, the distribution density of the first grid lines is increased in the first area, thereby improving the current collection capability of the cell. In addition, in conditions of weak light, scattered light and weak light can be more effectively absorbed to improve power generation efficiency.

[0028] Furthermore, multiple connecting lines are used to cross each of the first gate lines and the third gate lines to form an electrical connection, so that the gate lines on the first area are denser. In subsequent processes, when multiple battery cells are electrically connected through welding ribbons, there is no need to use welding ribbons for overlapping on the first area of ​​the battery cell, that is, the connecting lines replace part of the welding ribbons, so that the length of the welding ribbons is shortened. Since there is no need for overlapping welding of welding ribbons, there is no need to use a carrier material (film) or fixing glue for pre-fixation on the first area, thereby saving material costs.

[0029] Furthermore, since the first gate lines in the first region do not need to be overlapped with the soldering ribbon to form a welded connection, the solderability of the materials used for the first gate lines and connecting lines can be considered regardless of their material. This allows the use of materials with higher conductivity, eliminating the need for silver paste. Lower-cost materials such as copper can also meet the corresponding performance requirements. Furthermore, due to the wide range of material options, the thickness and pattern design of the first gate lines and connecting lines are not restricted by the original materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description, are used to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention, and are included in and constitute a part of this specification.

[0031] Figure 1 This is a schematic diagram of the back structure of a whole battery cell according to an embodiment of the present utility model;

[0032] Figure 2A This is a schematic diagram of the front structure of a whole battery cell according to an embodiment of the present utility model;

[0033] Figure 2B This is a schematic diagram of the front structure of a whole battery cell according to another embodiment of the present invention;

[0034] Figure 3 It is a partial structural diagram of the electrical connection structure according to an embodiment of the present utility model;

[0035] Figure 4 1 is a front structural schematic diagram of a battery string according to an embodiment of the present utility model;

[0036] Figure 5 is a front structural schematic diagram of a battery string according to another embodiment of the present utility model;

[0037] Figure 6 It is a schematic side view of the structure of a photovoltaic cell string (glue dispensing) according to an embodiment of the present utility model;

[0038] Figure 7 It is a side view structural diagram of a photovoltaic cell string (glue dispensing) according to another embodiment of the present utility model;

[0039] Figure 8 1 is a schematic side view of a photovoltaic cell string (film-coated) according to an embodiment of the present invention;

[0040] Figure 9 1 is a schematic side view of a photovoltaic cell string (film-coated) according to another embodiment of the present invention;

[0041] Figure 10 It is a schematic cross-sectional structural diagram of a photovoltaic laminate according to an embodiment of the present utility model.

[0042] Figure numerals: 11, first gate line; 12, second gate line; 13, third gate line; 14, fourth gate line; 15, connecting line; 16, welding ribbon; 21, curing glue; 22a, front covering film; 22b, rear covering film; 31, cover plate; 32, back plate; 33, encapsulation film; E1, first area; E2, second area; E3, third area. DETAILED DESCRIPTION

[0043] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0044] During the photovoltaic cell manufacturing process, the process of splitting the cell into half cells usually occurs after the entire cell has completed the metallization process, that is, after the screen printing of the grid lines and the sintering steps. Specifically, after the photovoltaic cell undergoes the steps of texturing, diffusion, etching, coating, screen printing and sintering, it will be tested and sorted before being cut. The cutting process is to cut a standard cell into two or more sliced ​​cells, the purpose of which is to improve the power and efficiency of the photovoltaic module.

[0045] Figure 1 This is a schematic diagram of the back structure of a whole battery cell according to an embodiment of the present utility model; Figure 2A This is a schematic diagram of the front structure of a whole battery cell according to an embodiment of the present utility model. Figure 1 、 Figure 2A As shown in the figure, the back side (backlight side) and front side (light-receiving side) of a standard cell after the metallization process are completed are shown respectively. The first surface is taken as the back side as an example to explain that when forming a cell string, a standard cell is cut into two or more sliced ​​cells. The photovoltaic cell below is introduced by taking a half-cell cell as an example. A half-cell cell means: a standard cell is cut into two half-cell cells. Figure 1 As shown, along the symmetry axis in the up-down direction, a standard cell is cut into two half-cells, and the back of each half-cell includes a first area E1, a second area E2 and a third area E3, that is, the electrical connection structure includes a dense grid structure on the first area E1, a junction structure on the third area E3 and a sparse grid structure on the second area E2 in sequence.

[0046] For example, the front side of a standard cell may have a conventional grid line density (sparse grid structure), which is equivalent to a plurality of second grid lines 12 and a smaller distribution density distributed on the front side of the standard cell, without a dense grid structure formed by a plurality of first grid lines 11 with a higher distribution density, such as Figure 2A shown.

[0047] For example, the front side of a standard cell may also have the same electrical connection structure as the back side, which is equivalent to having a plurality of second grid lines 12 and their corresponding distribution density (sparse grid structure) distributed on the front side of the standard cell, as well as a plurality of first grid lines 11 with a higher distribution density (dense grid structure), and a junction structure, such as Figure 2BAs shown, the electrical connection structure on the front side of the half-cut solar cell includes a dense grid structure, a junction structure and a sparse grid structure, wherein: Figure 2B It is a schematic diagram of the front structure of a whole battery cell according to another embodiment of the present invention.

[0048] Figure 3 This is a partial structural diagram of the electrical connection structure according to the embodiment of the present utility model. Figure 3 As shown, an electrical connection structure is formed on the first surface of the photovoltaic cell of an exemplary embodiment of the present invention, and the electrical connection structure includes a plurality of first grid lines 11, a plurality of second grid lines 12, a plurality of third grid lines 13 arranged along a first direction and a plurality of connecting lines 15 arranged along a second direction, and the first direction is perpendicular to the second direction; the first surface has a first area E1, a second area E2 and a third area E3 located between the first area E1 and the second area E2, a plurality of first grid lines 11 are arranged in the first area E1, a plurality of second grid lines 12 are arranged in the second area E2, and a plurality of third grid lines 13 are arranged in the third area E3; the distribution density of the plurality of first grid lines 11 is greater than the distribution density of the plurality of second grid lines 12; the width of the third grid line 13 is greater than the width of the second grid line 12, and the width of the second grid line 12 is greater than the width of the first grid line 11; each connecting line 15 is connected to each first grid line 11 and each third grid line 13 and extends in a direction close to the second grid line 12.

[0049] For example, along the first direction, the first surface is sequentially distributed with a first area E1, a third area E3, and a second area E2, and a plurality of first gate lines 11, a plurality of third gate lines 13, and a plurality of second gate lines 12 are all arranged in parallel, that is, the plurality of first gate lines 11, the plurality of third gate lines 13, and the plurality of second gate lines 12 all extend along the second direction. The spacing between the plurality of first gate lines 11 is smaller than the spacing between the plurality of second gate lines 12, that is, the distribution density of the first gate lines 11 in the first area E1 is higher than the distribution density of the second gate lines 12 in the second area E2. In the third area E3, that is, the boundary area between the first area E1 and the second area E2, the third gate lines 13 are widened, that is, the width of the third gate lines 13 is greater than the width of the second gate lines 12, and the width of the second gate lines 12 is greater than the width of the first gate lines 11.

[0050] For example, multiple connecting lines 15 are arranged along the second direction, each connecting line 15 spans each first gate line 11 and forms an electrical connection therewith. After spanning the first area E1, each connecting line 15 continues to extend toward the third area E3 and the second area E2, spans the third gate line 13 and forms an electrical connection therewith, and continues to extend toward the direction close to the second gate line 12. Thus, the thicker third gate line 13 in the third area E3 and the connecting lines 15 electrically connected thereto can enhance current collection. The spanning of the connecting lines 15 across each first gate line 11 is equivalent to increasing the density of the gate lines in the first area E1, thereby assisting in current collection.

[0051] In some embodiments, the cell needs to have welding strips 16 placed on the second area E2 and the third area E3 to lead out the current of each grid line, and can also form interconnections with adjacent cell pieces to form a cell string.

[0052] When soldering ribbons 16 are provided on the cell, the plurality of soldering ribbons 16 are also arranged along the second direction. After crossing over and electrically connecting to each second grid line 12 in the second region E2, they cross over and electrically connect to the third grid lines 13, and then continue to extend toward the first grid lines 11. Thus, in the third region E3, the interwoven structure formed by the plurality of third grid lines 13, the plurality of connecting lines 15, and the plurality of soldering ribbons 16 ensures a stable connection, thereby effectively collecting current.

[0053] Thus, it can be seen that due to the high density distribution of the first grid lines 11 and the electrical connection between each first grid line 11 through multiple connecting lines 15, there is no need to set a welding ribbon 16 to collect the current of each first grid line 11, that is, there is no need to set a welding ribbon 16 in the first area E1, and welding ribbons 16 are only set in the second area E2 and the third area E3 to collect the current of the second grid lines 12 and the third grid lines 13. Compared with the prior art that sets the welding ribbon 16 along the entire area of ​​the first surface, the welding ribbon 16 of the exemplary embodiment of the present utility model can be shorter, thereby saving costs; at the same time, when setting the welding ribbon 16, it is necessary to use a dispensing process or a laminating process to pre-fix the welding ribbon 16 to the battery cell, and use a low temperature (higher than the melting point of the tin material of the welding ribbon 16) to weld the welding ribbon 16 to the battery cell and each grid line during the lamination process to form an electrical connection. Therefore, no materials for the dispensing process or the laminating process are required in the first area E1, thereby saving costs.

[0054] Furthermore, since the first gate lines 11 do not need to be soldered to the soldering ribbon 16, the material of the first gate lines 11 does not need to consider the solderability of the paste, and a highly conductive paste can be used. At the same time, the material, thickness, and pattern design and selection of the gate lines are not affected by the soldering function. For example, the material of the first gate lines 11 can be silver-clad copper, electroplated copper, or aluminum-silver paste, which are lower in cost than silver paste.

[0055] In order to ensure the welding effect between the second grid lines 12 , the third grid lines 13 and the welding strips 16 , the second grid lines 12 , the third grid lines 13 are made of traditional silver paste.

[0056] like Figure 3 As shown, in the photovoltaic cell of the exemplary embodiment of the present invention, the electrical connection structure further includes at least one fourth grid line 14, which is connected to at least one connecting line 15 and is located in the third area E3; the fourth grid line 14 extends along the first direction.

[0057] For example, when the number of the fourth gate line 14 is one, the fourth gate line 14 may cross over each of the connection lines 15 and the welding ribbons 16 and form an electrical connection therewith.

[0058] When there are multiple fourth gate lines 14 , each fourth gate line 14 crosses over a corresponding connection line 15 and forms an electrical connection therewith.

[0059] The junction structure formed by the connecting line 15 , the third gate line 13 , the fourth gate line 14 and the welding strip 16 can further enhance the current collection capability.

[0060] Exemplarily, the number of the above-mentioned connecting lines 15 can be equal to or greater than the number of welding strips 16. When the number of connecting lines 15 is equal to the number of welding strips 16, in the third area E3, along the second direction, the connecting lines 15 and the welding strips 16 are alternately distributed in sequence.

[0061] In some embodiments, the width and height of the fourth gateline 14 are respectively the same as the width and height of the second gateline 12. For example, the width of the second gateline 12 is 20 μm to 30 μm and the height is 12 μm to 16 μm; the width of the fourth gateline 14 is 20 μm to 30 μm and the height is 12 μm to 16 μm. It should be noted that the height direction of the gateline refers to the direction in which the gateline protrudes from the surface of the solar cell.

[0062] Exemplarily, the first gate line 11 has a width of 10 μm to 15 μm and a height of 6 μm to 8 μm. Compared with the second gate line 12 , the first gate line 11 has a larger aspect ratio (ie, it can be distributed more densely), which can improve the battery cell's ability to collect current.

[0063] In some embodiments, the ratio of the area of ​​the first region E1 to the first surface is 1:(2-4). That is, the area of ​​the dense grid structure on half of the cell is 1 / 4-1 / 2 of the area of ​​the first surface of the half of the cell, and the rest is the second region E2 and the third region E3.

[0064] In some embodiments, the ratio of the number of first gate lines 11 to the number of second gate lines 12 ranges from 2 to 3. That is, the number of first gate lines 11 in the first region E1 is 2 to 3 times the number of second gate lines 12 in the second region E2, illustratively 2.5 times.

[0065] In some embodiments, the ratio of the width of the third gate line 13 to the width of the second gate line 12 is in a range of 1.5 to 2.5; and the height of the third gate line 13 is consistent with the height of the second gate line 12 .

[0066] Since the third gate line 13 is thicker than the second gate line 12, for example, the ratio of the width of the third gate line 13 to the width of the second gate line 12 is 2; the second gate line 12 is thicker than the first gate line 11, and the height of the third gate line 13 is the same as the height of the second gate line 12, when the welding strip 16 overlaps the third gate line 13 in the third area E3, the welding effect is consistent with that of the second gate line 12, and the current collection capability in the third area E3 is stronger.

[0067] In some embodiments, the material of the first gate lines 11 is silver-clad copper or electroplated copper; the material of the second, third, and fourth gate lines 12, 13, and 14 is silver paste. This means that the material paste of the first gate lines 11, which do not need to be welded to the soldering ribbon 16 to collect current, has more choices and greater freedom. However, the material of the second, third, and fourth gate lines 12, 13, and 14, which need to be welded to the soldering ribbon 16, not only needs to meet conductivity requirements, but also needs to consider the welding performance of the material with the soldering ribbon 16, the corresponding size requirements, and the requirements for the pattern printed on the solar cell. Therefore, the material selection is less selective, and silver paste is generally used.

[0068] Exemplarily, the soldering ribbon 16 is a low-temperature soldering ribbon 16 , the melting point of the tin material coated on the soldering ribbon 16 is 140° C. to 150° C., and the diameter of the soldering ribbon 16 is 0.05 mm to 0.3 mm.

[0069] In some embodiments, the photovoltaic cell has a second surface opposite to the first surface, and an electrical connection structure is formed on the second surface; the first area E1 on the first surface is opposite to the second area E2 on the second surface, and the second area E2 on the first surface is opposite to the first area E1 on the second surface.

[0070] For a whole battery cell, Figure 1 As shown, on the back side (first surface), the two first regions E1 are both located in the middle part, and the two second regions E2 are respectively located on both sides of the middle part, that is, two dense grid structures are in the middle and two sparse grid structures are on both sides; on the front side, the dense grid structure may not be used, that is, the sparse grid structure is used on the second surface, as shown in FIG. Figure 2AAs shown; optionally, a dense grid structure may also be provided on the front side, with the two second regions E2 on the second surface located in the middle portion, and the two first regions E1 located on both side regions, as shown Figure 2B As shown, the battery cells are cut into half pieces, with the sparse grid structure on the front side facing the dense grid structure on the back side, and the dense grid structure on the front side facing the sparse grid structure on the back side, so that multiple half-piece battery cells are electrically connected through the arrangement of welding strips 16 to form a battery string.

[0071] An exemplary embodiment of the present invention also provides a photovoltaic cell string, comprising a plurality of photovoltaic cells and a plurality of welding ribbons 16 arranged along a second direction, wherein the plurality of photovoltaic cells are electrically connected through the plurality of welding ribbons 16, and at least one photovoltaic cell is a photovoltaic cell of the above-mentioned embodiment; each welding ribbon 16 is connected to each second grid line 12 and each third grid line 13 and extends in a direction close to the first grid line 11.

[0072] In actual applications, the process of electrically connecting multiple photovoltaic cells through welding ribbons 16 is to first fix the welding ribbons 16 at the corresponding positions of the cells by pre-fixing, and then use a laminator to weld the tin-coated welding ribbons 16 to the corresponding grid lines on the cells in the temperature environment of the lamination process, thereby collecting the current of the cells and forming the individual cells into a cell string.

[0073] There are two main ways to pre-fix the solder ribbon 16, one is a glue dispensing solution, and the other is a laminating solution.

[0074] Figure 4 : is a schematic diagram of the front structure of a battery string according to an embodiment of the present utility model. Figure 4 As shown, a curing glue 21 is printed on the sparse grid structure and the junction structure of the battery cells of the battery string, that is, the second area E2 and the third area E3 on the front side, by a printing machine, and the soldering ribbon 16 is placed on the curing glue 21 and overlapped with the second grid line 12 and the third grid line 13. Then, the curing glue 21 is cured through a curing process, and the battery cells are connected in series. In the subsequent lamination process, the soldering ribbon 16 is welded to the second grid line 12 and the third grid line 13 in a temperature environment higher than that of the tin material on the soldering ribbon 16 to form an electrical connection.

[0075] Figure 6 It is a schematic side view of the structure of a photovoltaic cell string (glue dispensing) according to an embodiment of the present utility model; Figure 7 This is a side view of a photovoltaic cell string (glue dispensing) according to another embodiment of the present invention. Figure 6As shown, the front of the cell is entirely a sparse grid structure, while the back is sequentially a sparse grid structure, a junction structure, and a dense grid structure. The sparse grid structure in the second area E2 on the back of the left cell is led out via a soldering ribbon 16 and can be connected to an interconnect bar or to the other left cell. The sparse grid structure on the front of the left cell is connected to the sparse grid structure in the second area E2 on the back of the right cell via a soldering ribbon 16, and the sparse grid structure on the front of the right cell is connected to the other right cell or bus bar via a soldering ribbon 16.

[0076] like Figure 7 As shown, the front of the cell has a dense grid structure in the first region E1, a junction structure in the third region E3, and a sparse grid structure in the second region E2, while the back has a sparse grid structure, a junction structure, and a dense grid structure. The sparse grid structure in the second region E2 on the back of the left cell is led out via a soldering ribbon 16 and can be connected to an interconnect bar or to the other left cell. The sparse grid structure in the second region E2 on the front of the left cell is connected to the sparse grid structure in the second region E2 on the back of the right cell via a soldering ribbon 16. The sparse grid structure in the second region E2 on the front of the right cell is also connected to the other right cell or bus bar via a soldering ribbon 16.

[0077] Figure 5 is a front structural diagram of a battery string according to another embodiment of the present invention; Figure 5 As shown, a front film 22a is placed on the sparse grid structure and the junction structure of the battery cell of the battery string, that is, on the second area E2 and the third area E3 on the front side, by a corresponding machine, and a rear film 22b is placed on the second area E2 and the third area E3 on the back side. Through an infrared light box, the front film 22a and the rear film 22b are laminated and fixed to the battery cell with the soldering tape 16, thereby connecting the battery cells in series. And in the subsequent lamination process, the soldering tape 16 is welded to the second grid line 12 and the third grid line 13 in a temperature environment higher than that of the tin material on the soldering tape 16 to form an electrical connection. It should be noted that in order to clearly show the grid line structure of each area of ​​the battery cell in the battery string, in the sparse grid structure on the front side, the front film 22a is only exemplarily placed on the sparse grid structure on the far left.

[0078] Figure 8 1 is a schematic side view of a photovoltaic cell string (film-coated) according to an embodiment of the present invention; Figure 9 : is a side view structural diagram of a photovoltaic cell string (film) according to another embodiment of the present invention. Figure 8 The photovoltaic cell string shown is connected to the cell sheets by the welding ribbon 16. Figure 6 The photovoltaic cell strings shown are basically the same, except that the soldering ribbons 16 are pre-fixed with a film on the area of ​​the cell where the soldering ribbons 16 are provided, and Figure 6The photovoltaic cell string shown is pre-fixed with the soldering ribbon 16 by using glue dispensing.

[0079] like Figure 9 The photovoltaic cell string shown is connected to the cell sheets by the welding ribbon 16. Figure 7 The photovoltaic cell strings shown are basically the same, except that the soldering ribbons 16 are pre-fixed with a film on the area of ​​the cell where the soldering ribbons 16 are provided, and Figure 7 The photovoltaic cell string shown is pre-fixed with the soldering ribbon 16 by using glue dispensing.

[0080] Depend on Figure 4-Figure 9 As shown, the battery string of the exemplary embodiment of the present invention does not require glue, coating, or welding ribbons 16 for the dense grid structure of the first area E1 on the front and back of the battery cell. Glue or coating is only required on the junction structure of the second area E2 and the sparse grid structure and junction structure of the third area E3 to pre-fix the corresponding welding ribbons 16. This can save the corresponding coating or glue material, while reducing the material requirements for the first grid line 11 in the first area E1, while improving the current collection capability and reducing the production cost.

[0081] Figure 10 Schematic diagram of the cross-sectional structure of the photovoltaic laminate according to the embodiment of the present utility model. Figure 10 As shown, an exemplary embodiment of the present invention further provides a photovoltaic laminate comprising the photovoltaic cell string in the above embodiment.

[0082] The photovoltaic laminate comprises a cover plate 31, an encapsulation film 33, a photovoltaic cell string, an encapsulation film 33, and a back plate 32 from the front (light-receiving side) to the back. After the above five layers of materials are stacked, they are fixed together through a lamination process, and then after framing, curing, cleaning and other processes, a photovoltaic module is produced.

[0083] An exemplary embodiment of the present invention further provides a photovoltaic assembly, comprising the photovoltaic laminate of the above embodiment.

[0084] The technical advantages of the above-mentioned photovoltaic laminates and photovoltaic modules over the prior art are consistent with the technical advantages of the photovoltaic cells of the above-mentioned embodiment, and will not be repeated here.

[0085] Those skilled in the art will appreciate that the above embodiments are merely intended to clearly illustrate the present invention and are not intended to limit the scope of the present invention. Other variations or modifications may be made based on the above disclosure, and such variations or modifications are still within the scope of the present invention.

Claims

1. A photovoltaic cell, characterized in that: An electrical connection structure is formed on the first surface of the photovoltaic cell, the electrical connection structure comprising a plurality of first grid lines, a plurality of second grid lines, a plurality of third grid lines arranged along a first direction, and a plurality of connection lines arranged along a second direction, wherein the first direction is perpendicular to the second direction; The first surface has a first area, a second area and a third area located between the first area and the second area, the plurality of first gate lines are arranged in the first area, the plurality of second gate lines are arranged in the second area, and the plurality of third gate lines are arranged in the third area; The distribution density of the plurality of first gate lines is greater than the distribution density of the plurality of second gate lines; The width of the third gate line is greater than the width of the second gate line; Each of the connecting lines is connected to each of the first gate lines and each of the third gate lines and extends toward the second gate line.

2. The photovoltaic cell according to claim 1, characterized in that: The electrical connection structure further includes at least one fourth gate line, the at least one fourth gate line being connected to at least one connecting line and being located in the third area; The fourth gate line extends along the first direction.

3. The photovoltaic cell according to claim 2, characterized in that: The width and height of the fourth gate line are respectively consistent with the width and height of the second gate line.

4. The photovoltaic cell according to any one of claims 1 to 3, characterized in that: The area ratio of the first region to the first surface is 1:(2-4).

5. The photovoltaic cell according to any one of claims 1 to 3, characterized in that: The ratio of the number of the first gate lines to the number of the second gate lines ranges from 2 to 3.

6. The photovoltaic cell according to any one of claims 1 to 3, characterized in that: The ratio of the width of the third gate line to the width of the second gate line is in the range of 1.5 to 2.5; and / or, The height of the third gate line is consistent with the height of the second gate line.

7. The photovoltaic cell according to claim 6, characterized in that: The material of the first gate line is silver-clad copper or electroplated copper; and / or, The second gate line and the third gate line are made of silver.

8. The photovoltaic cell according to claim 1, characterized in that: The photovoltaic cell has a second surface opposite to the first surface, and the electrical connection structure is formed on the second surface; and / or, The first area on the first surface is opposite to the second area on the second surface, and the second area on the first surface is opposite to the first area on the second surface.

9. A photovoltaic cell string, characterized in that: comprising a plurality of photovoltaic cells and a plurality of welding strips arranged along the second direction, wherein the plurality of photovoltaic cells are electrically connected through the plurality of welding strips, and at least one of the photovoltaic cells is a photovoltaic cell according to any one of claims 1 to 8; Each of the welding strips is connected to each of the second gate lines and each of the third gate lines and extends toward the first gate lines.

10. A photovoltaic module, characterized in that: The photovoltaic cell string according to claim 9 is included.

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