Solar cell and photovoltaic module

Abstract

The utility model discloses a solar cell piece and a photovoltaic module, the front surface of the solar cell piece comprises front surface fine grid lines arranged along a first direction, the back surface of the solar cell piece comprises back surface fine grid lines arranged along the first direction, and the back surface fine grid lines and the front surface fine grid lines are not overlapped along the direction vertical to the plane where the solar cell piece is located. The half-piece boundary divides the battery piece into a first half piece and a second half piece, the first edge is located on the first half piece, and the second edge is located on the second half piece; the distance between at least two edge back fine grid lines close to the first edge and / or the second edge is a; in the first half piece and the second half piece, the distance between at least two boundary back thin grid lines close to the half piece boundary is b; uniformly distributed back surface fine grid lines are arranged between the edge back surface fine grid lines and the boundary back surface fine grid lines, and the distance between every two adjacent uniformly distributed back surface fine grid lines is c; a < c and b < c. According to the invention, the proportion of battery stripe marks caused by a laser enhanced contact optimization process is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaics, and more specifically, to a solar cell and a photovoltaic assembly. Background Art

[0002] Solar energy is one of the energy sources currently being developed at home and abroad. It uses photovoltaic cells to absorb the sun's light energy and convert it into electrical energy. It has great potential and prospects to replace traditional energy. Among various solar cells, silicon-based solar cells account for 90% of the total market share.

[0003] At present, the laser enhanced contact optimization (LECO) process is used in the preparation of solar cells. The laser enhanced contact optimization (LECO) process separates the two key steps of passivation layer erosion and contact formation during high-temperature sintering, thereby achieving further precise control of the sintering process. LECO first applies a reverse bias of 10V or more to the cell, and at the same time generates a large number of charge carriers by locally irradiating the cell with a focused laser beam. The carriers are transmitted along the low contact resistance path, inducing silver-silicon interdiffusion, thereby reducing the contact resistance. The preferred path of the local current is the low resistance path, which must pass between the emitter and Ag under the gate line and leads to high current density; the high current density leads to hot spots, sintering occurs at the corresponding points, and silver and silicon are mutually diffused. The duration of the entire sintering process matches the carrier lifetime, and the laser stops quickly after passing, thereby achieving maximum retention of the original passivation layer and avoiding carrier recombination caused by direct contact between the metal and silicon substrate; then there is a cooling process, the heating time caused by the current is between microseconds and milliseconds, and the temperature near the melting point will drop rapidly, which mainly depends on the carrier lifetime. However, in the prior art, when conducting EL (electroluminescence) tests on solar cells, it is found that the percentage of poor printing of fine grid stripes is as high as over 10%.

[0004] Therefore, there is an urgent need for a solar cell and a photovoltaic module that can improve the problem of poor printing of fine grid stripes. Utility Model Content

[0005] In view of this, the utility model provides a solar cell and a photovoltaic module to improve the problem of poor printing of fine grid stripes.

[0006] In one aspect, the utility model provides a solar cell, comprising a front side and a back side opposite to each other, wherein the front side comprises front side fine grid lines arranged along a first direction, and the back side comprises back side fine grid lines arranged along the first direction;

[0007] Along the direction perpendicular to the plane where the solar cell is located, the back fine grid lines and the front fine grid lines do not overlap;

[0008] Along the first direction, the solar cell comprises a first edge, a half-cell dividing line and a second edge, the half-cell dividing line is located at a midline position between the first edge and the second edge; the half-cell dividing line divides the cell into a first half cell and a second half cell, the first edge is located in the first half cell, and the second edge is located in the second half cell;

[0009] The back fine grid lines include edge back fine grid lines, boundary back fine grid lines and uniformly distributed back fine grid lines, wherein:

[0010] The spacing between at least two edge back fine grid lines close to the first edge and / or the second edge is a;

[0011] In the first half and the second half, the spacing between at least two boundary back fine grid lines close to the half-sheet dividing line is b;

[0012] The back fine grid lines between the edge and the boundary are uniformly distributed back fine grid lines, and the spacing between two adjacent uniformly distributed back fine grid lines is c;

[0013] a<c, b<c.

[0014] Optionally, the shortest distance between the fine back grid lines at the boundary of the first half of the sheet and the fine back grid lines at the boundary of the second half of the sheet is d, and 1 mm≤d≤1.05 mm.

[0015] Optional, a=b.

[0016] Optionally, the spacings between the front fine grid lines are all equal, which is equal to the spacing between two adjacent evenly distributed back fine grid lines.

[0017] Optionally, along a direction perpendicular to the plane where the solar cell is located, the back thin grid lines are located between two adjacent front thin grid lines.

[0018] Optionally, along a direction perpendicular to the plane where the solar cell is located, the intervals between the evenly distributed back thin grid lines and two adjacent front thin grid lines are all equal to e.

[0019] Optionally, the front side further includes a front side border line, and the front side fine grid line is connected to the front side border line;

[0020] The back side also includes a back side frame line, and the back side fine grid line is connected to the back side frame line;

[0021] Along the direction perpendicular to the plane where the solar cell is located, the front frame line and the back frame line do not overlap.

[0022] Optionally, the total number of the front fine grid lines and the total number of the back fine grid lines are equal, and the number of the back fine grid lines is proportional to the size of the solar cell.

[0023] Optionally, the size of the solar cell includes 156mm×156mm, 182mm×182mm, 210mm×210mm or 266mm×266mm;

[0024] The number of fine grid lines on the back side includes 148, 154, 156, 176, 160, 162, 164, 182 or 200.

[0025] On the other hand, the utility model also provides a photovoltaic module, including the above-mentioned solar cell, multiple solar cell cells form a battery string, and also include a first packaging film and a second packaging film located on both sides of the battery string, and a first cover plate located on the side of the first packaging film away from the battery string and a second cover plate located on the side of the second packaging film away from the battery string.

[0026] Compared with the prior art, the solar cell and photovoltaic module provided by the utility model achieve at least the following beneficial effects:

[0027] In the prior art, the fine grid lines on the front and back of the solar cell are partially overlapped, and the laser enhanced contact optimization laser power is applied to the overlapped part of the front grid lines and the back grid lines. Since the polysilicon layer on the back is thinner, it is easy to burn through the back, resulting in poor stripe printing of the solar cell. The present application optimizes the fine grid line pattern on the back of the cell. The solar cell of the utility model includes a relative front and back, the front side includes front fine grid lines arranged along a first direction, the back side includes back fine grid lines arranged along the first direction, along the direction perpendicular to the plane where the solar cell is located, the back fine grid lines and the front fine grid lines do not overlap, and the back fine grid lines and the front fine grid lines are completely staggered; along the first direction, the solar cell includes a first edge, a half-piece dividing line, and a second edge, and the half-piece dividing line is located at the midline position of the first edge and the second edge; the half-piece dividing line divides the cell into a first half and a second half, the first edge is located in the first half, and the second edge is located in the second half; the back fine grid lines include edge back fine grid lines, boundary back fine grid lines, and Fine grid lines and evenly distributed back fine grid lines, wherein the spacing between at least two edge back fine grid lines close to the first edge and / or the second edge is a; in the first half sheet and the second half sheet, the spacing between at least two boundary back fine grid lines close to the half-sheet dividing line is b; the spacing between the edge back fine grid lines and the boundary back fine grid lines is evenly distributed back fine grid lines, and the spacing between two adjacent evenly distributed back fine grid lines is c; a<c, b<c, the spacing between the back fine grid lines is not completely evenly divided, ensuring that it is completely staggered with the front fine grid lines. Since the front fine grid lines and the back grid lines do not overlap, when the laser enhanced contact optimization technology is used, the laser hits the front grid lines and will not easily burn through the back side, thereby eliminating the stripe print.

[0028] Of course, any product implementing the present utility model does not necessarily need to achieve all of the above technical effects at the same time.

[0029] Other features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention.

[0031] Figure 1 It is a schematic diagram of the back plane structure of a solar cell in the related art;

[0032] Figure 2 This is a schematic diagram of the back plane structure of a solar cell provided by the utility model;

[0033] Figure 3 yes Figure 2 A partial enlarged view of the middle M region;

[0034] Figure 4 yes Figure 2 A local magnified image of the middle N region;

[0035] Figure 5 This is a schematic diagram of the back plane structure of another solar cell provided by the utility model;

[0036] Figure 6 It is a structural schematic diagram of a photovoltaic component provided by the utility model. DETAILED DESCRIPTION

[0037] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention.

[0038] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present invention, its application, or uses.

[0039] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0040] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0041] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0042] In view of the fact that the EL (electroluminescence) test of solar cells in the related art found that the proportion of fine grid stripe printing failure was as high as more than 10%, the inventor conducted the following research on the related art, referring to Figure 1 , Figure 1 It is a schematic diagram of the back plane structure of a solar cell in the related art. In the prior art, the front fine grid lines 01 and the back fine grid lines 02 of the solar cell 000 are completely overlapped. The laser enhanced contact optimization laser power is hit on the overlapping part of the front grid lines 01 and the back grid lines 02. Since the polysilicon layer on the back is thinner, it is easy to burn through the back, resulting in poor stripe printing of the solar cell 000.

[0043] In view of this, the utility model provides a solar cell and a photovoltaic module. The specific embodiments of the solar cell will be described in detail below.

[0044] Reference Figures 2 to 4 , Figure 2 This is a schematic diagram of the back plane structure of a solar cell provided by the utility model. Figure 3 yes Figure 2 A partial enlarged view of the middle M area. Figure 4 yes Figure 2 The utility model provides a solar cell 100, comprising a front side (not shown in the figure) and a back side BA, the front side comprising front side fine grid lines 1 arranged along a first direction X, and the back side BA comprising back side fine grid lines 2 arranged along the first direction X; Figure 1 The dotted line in the middle represents the front fine grid line 1, which is located on the front side of the solar cell 100, and its position is indicated by the dotted line. Of course, the solar cell 100 also includes main grid lines located on the front and back sides BA, and the main grid lines extend along the first direction X. The front fine grid lines 1 and the back fine grid lines 2 both extend along the second direction Y. In this embodiment, the first direction X intersects with the second direction Y, that is, the arrangement direction of the back fine grid lines 2 intersects with the extension direction of the back fine grid lines 2. It can be understood that after the solar cell 100 is sliced, the first direction X is the short side direction of the half-cell.

[0045] Along the direction perpendicular to the plane of the solar cell 100, the back fine grid lines 2 do not overlap with the front fine grid lines 1, and the back fine grid lines 2 and the front fine grid lines 1 are completely staggered. When the laser enhanced contact optimized laser power is hit on the front grid lines, since the front fine grid lines 1 and the back BA grid lines do not overlap, it is not easy to burn through the back BA, thereby eliminating the stripe marks.

[0046] Along the first direction X, the solar cell 100 includes a first edge 3, a half-cell dividing line 5, and a second edge 4. The half-cell dividing line 5 is located at the midline position of the first edge 3 and the second edge 4; the half-cell dividing line 5 divides the cell into a first half cell 91 and a second half cell 92. The first edge 3 is located in the first half cell 91, and the second edge 4 is located in the second half cell 92. It should be noted that the half-cell dividing line 5 here is a virtual dividing line, which can be used as a dividing line for subsequent cutting and splitting of the solar cell 100. When the solar cell 100 is cut, it can be divided into the first half cell 91 and the second half cell 92. After the splitting, the first edge 3 and the half-cell dividing line 5 serve as two opposite edges of the first half cell 91 along the first direction X, and the half-cell dividing line 5 and the second edge 4 serve as two opposite edges of the second half cell 92 along the first direction X.

[0047] The back side fine grid lines 2 include edge back side fine grid lines 6, boundary back side fine grid lines 7 and uniformly distributed back side fine grid lines 8, and the spacing between at least two edge back side fine grid lines 6 close to the first edge 3 and / or the second edge 4 is a; in the first half sheet 91 and the second half sheet 92, the spacing between at least two boundary back side fine grid lines 7 close to the half-sheet dividing line 5 is b; the back side fine grid lines 8 are uniformly distributed between the edge back side fine grid lines 6 and the boundary back side fine grid lines 7, and the spacing between two adjacent uniformly distributed back side fine grid lines 8 is c; a<c, b<c.

[0048] Reference Figures 2 to 4 , the edge back fine grid line 6 refers to the fine grid line close to the first edge 3 and the second edge 4, where there can be 2 or 3 edge back fine grid lines 6, and this embodiment only uses the number of edge back fine grid lines 6 as 2 for schematic illustration, and this embodiment reduces the spacing between the two edge back fine grid lines 6, thereby staggering them with the front fine grid line 1. Of course, the distance between the edge back fine grid line 6 close to the uniformly distributed back fine grid line 8 and the nearest uniformly distributed back fine grid line 8 is still c; the boundary back fine grid line 7 refers to the fine grid line close to the half-sheet dividing line 5, where there can be 2 or 3 boundary back fine grid lines 7, and this embodiment only uses the number of boundary back fine grid lines 7 as 2 for schematic illustration, and this embodiment reduces the spacing between the two boundary back fine grid lines 7, thereby staggering them with the front fine grid line 1. Of course, the distance between the boundary back fine grid line 7 close to the uniformly distributed back fine grid line 8 and the nearest uniformly distributed back fine grid line 8 is still c. That is, only the distance between two back fine grid lines 2 (i.e., edge back fine grid lines 6) near the first edge 3 and / or the second edge 4 is reduced, and the distance between two back fine grid lines 2 (i.e., boundary back fine grid lines 7) near the half-chip dividing line 5 is reduced.

[0049] The spacing a between the two edge back fine grid lines 6 is smaller than the spacing c between the two evenly distributed back fine grid lines 8, and the spacing b between the two boundary back fine grid lines 7 is smaller than the spacing c between the two evenly distributed back fine grid lines 8, that is, this embodiment reduces the spacing between the two back fine grid lines 2 near the first edge 3 and / or the second edge 4, and also reduces the spacing between the two back fine grid lines 2 near the half-cell dividing line 5, thereby ensuring that the back fine grid lines 2 and the front fine grid lines 1 do not overlap in the direction perpendicular to the plane of the solar cell 100. When the laser enhanced contact optimized laser power is hit on the front grid lines, since the front fine grid lines 1 and the back BA grid lines do not overlap, it is not easy to burn through the back BA, thereby eliminating the stripe print.

[0050] In some optional embodiments, continue to refer to Figure 2 The shortest distance between the fine grid lines 7 on the back side of the first half sheet 91 and the fine grid lines 7 on the back side of the second half sheet 92 is d, 1 mm ≤ d ≤ 1.05 mm.

[0051] Optionally, the shortest distance d between the fine grid lines 7 on the back side of the first half sheet 91 and the fine grid lines 7 on the back side of the second half sheet 92 can be 1 mm, 1.01 mm, 1.02 mm, 1.03 mm, 1.04 mm, or 1.05 mm, or any other value between 1 mm and 1.05 mm, which is not specifically limited here.

[0052] It is understandable that if the shortest distance between the fine grid lines 7 on the back side of the first half-piece 91 and the fine grid lines 7 on the back side of the second half-piece 92 is too large, the space occupied will be wasted due to the lack of other grid lines in the gap before the space occupied, thus affecting the efficiency of the solar cell 100. If the shortest distance between the fine grid lines 7 on the back side of the first half-piece 91 and the fine grid lines 7 on the back side of the second half-piece 92 is too small, there is no reserved space for slicing, and it is easy to cut the fine grid lines in the first half-piece 91 or the fine grid lines in the second half-piece 92 during slicing. In this embodiment, the shortest distance d between the fine grid lines 7 on the back side of the first half-piece 91 and the fine grid lines 7 on the back side of the second half-piece 92 is between 1 mm and 1.05 mm, which can not only ensure the efficiency of the solar cell 100, but also ensure that sufficient cutting space is reserved.

[0053] For example, in the prior art, the front fine grid lines 01 and the back fine grid lines 02 completely overlap, and the spacing between the front fine grid lines 01 and the spacing between the back fine grid lines 02 are relative and completely evenly divided, with a distance of 1.034 mm. One of the embodiments of the present invention improves the back BA pattern, which is different from the fine grid line evenly divided pattern in the prior art. The present invention improves the back fine grid line 2 pattern, the spacing between the two edge back fine grid lines 6 is 0.732mm, the spacing between the two boundary back fine grid lines 7 is 0.564mm, the shortest distance between the boundary back fine grid lines 7 of the first half sheet 91 and the boundary back fine grid lines 7 of the second half sheet 92 is 1mm, and the remaining back fine grid lines 2 are evenly divided, which is 1.063mm, thereby ensuring that the back fine grid lines 2 and the front fine grid lines 1 do not overlap in the direction perpendicular to the plane where the solar cell 100 is located. When the laser enhanced contact optimized laser power is hit on the front grid lines, since the front fine grid lines 1 and the back BA grid lines do not overlap, it is not easy to burn through the back BA, thereby eliminating the stripe print.

[0054] In some optional embodiments, referring to Figure 5 , Figure 5 This is a schematic diagram of the back plane structure of another solar cell provided by the utility model. Figure 5 In this example, a=b.

[0055] The spacing between at least two edge back fine grid lines 6 near the first edge 3 and / or the second edge 4 is a, and the spacing between at least two boundary back fine grid lines 7 near the half-sheet dividing line 5 in the first half sheet 91 and the second half sheet 92 is b. In this way, when making the back fine grid line 2 pattern, it is convenient to make the edge back fine grid lines 6 and the boundary back fine grid lines 7, and the pattern is more regular.

[0056] In some optional embodiments, continue to refer to Figures 2 to 5 The spacing between the front fine grid lines 1 is equal, which is equal to the spacing between two adjacent evenly distributed back fine grid lines 8.

[0057] In this embodiment, the spacing between the front fine grid lines 1 is equal to c, the spacing between two adjacent uniformly distributed back fine grid lines 8 is c, and the spacing between the front fine grid lines 1 is equal to the spacing between the uniformly distributed back fine grid lines 8. In this way, there is no need to adjust the spacing between the uniformly distributed back fine grid lines 8, and only the spacing between the edge back fine grid lines 6 and the boundary back fine grid lines 7 needs to be adjusted, which is convenient for manufacturing.

[0058] In some optional embodiments, continue to refer to Figures 2 to 5 , along a direction perpendicular to the plane where the solar cell 100 is located, the back thin grid lines 2 are located between two adjacent front thin grid lines 1 .

[0059] from Figure 2 and Figure 5It can be seen that the back fine grid lines 2 and the front fine grid lines 1 are arranged alternately, that is, along the direction perpendicular to the plane where the solar cell 100 is located, the back fine grid lines 2 are located between two adjacent front fine grid lines 1, and along the direction perpendicular to the plane where the solar cell 100 is located, the back fine grid lines 2 and the front fine grid lines 1 do not overlap, and the back fine grid lines 2 and the front fine grid lines 1 are completely staggered. When the laser enhanced contact optimization laser power is hit on the front grid lines, since the front fine grid lines 1 and the back BA grid lines do not overlap, it is not easy to burn through the back BA, thereby eliminating the stripe print.

[0060] In some optional embodiments, continue to refer to Figures 2 to 5 , along the direction perpendicular to the plane where the solar cell 100 is located, the spacing between the evenly distributed back fine grid lines 8 and the two adjacent front fine grid lines 1 is equal to e.

[0061] like Figures 2 to 5 As shown, along the direction perpendicular to the plane where the solar cell 100 is located, the evenly distributed back fine grid lines 8 are exactly located at the midline position of the two adjacent front fine grid lines 1. Similarly, the front fine grid lines 1 are also located at the midline position of the two adjacent evenly distributed back fine grid lines 8. Therefore, the spacing between the evenly distributed back fine grid lines 8 and the two adjacent front fine grid lines 1 is equal to e. On the one hand, it can be ensured that along the direction perpendicular to the plane where the solar cell 100 is located, the back fine grid lines 2 and the front fine grid lines 1 do not overlap, and the back fine grid lines 2 and the front fine grid lines 1 are completely staggered. When the laser enhanced contact optimization laser power is hit on the front grid lines, since the front fine grid lines 1 and the back BA grid lines do not overlap, it will not be easy to burn through the back BA, thereby eliminating the stripe print. On the other hand, the front fine grid lines 1 and the back fine grid lines 2 are evenly distributed, which is convenient for graphic production.

[0062] In some optional embodiments, continue to refer to Figure 2 and Figure 5 The front side also includes a front side border line 11, and the front side fine grid line 1 is connected to the front side border line 11;

[0063] The back surface BA further includes a back surface frame line 12, and the back surface fine grid lines 2 are connected to the back surface frame line 12;

[0064] Along a direction perpendicular to the plane where the solar cell 100 is located, the front frame line 11 and the back frame line 12 do not overlap.

[0065] Figure 2 and Figure 5 The middle dotted line represents the front frame line 11 , which is arranged on the front side of the solar cell 100 , and the front fine grid line 1 is connected to the front frame line 11 . Figure 2 and Figure 5In the embodiment, the back frame line 12 is disposed on the back surface BA of the solar cell 100 , and the back fine grid lines 2 are connected to the back frame line 12 .

[0066] Along the direction perpendicular to the plane where the solar cell 100 is located, the front frame line 11 and the back frame line 12 do not overlap, and the front frame line 11 and the back frame line 12 are staggered. When the laser enhanced contact optimized laser power is hit on the front frame line 11, since the front frame line 11 and the back frame line 12 do not overlap, it is not easy to burn through the back BA, thereby eliminating the stripe mark.

[0067] In some optional embodiments, continue to refer to Figure 2 and Figure 5 The total number of the front fine grid lines 1 and the back fine grid lines 2 are equal, and the number of the back fine grid lines 2 is proportional to the size of the solar cell 100 .

[0068] It can be understood that the function of the fine grid lines is to collect current. The utility model reduces the distance between the two back fine grid lines 2 near the first edge 3 and / or the second edge 4, and also reduces the distance between the two back fine grid lines 2 near the half-cell dividing line 5. However, the number of the back fine grid lines 2 is not increased or decreased, and is equal to the total number of the front fine grid lines 1 and the total number of the back fine grid lines 2. This ensures the ability of the solar cell 100 to collect current and ensures the efficiency of the solar cell 100.

[0069] In addition, the number of fine grid lines 2 on the back side is proportional to the size of the solar cell 100, that is, the larger the size of the solar cell 100, the more fine grid lines 2 on the back side and the more fine grid lines 1 on the front side; the smaller the size of the solar cell 100, the fewer fine grid lines 2 on the back side and the fewer fine grid lines 1 on the front side, thereby ensuring the ability of the solar cell 100 to collect current and ensuring the efficiency of the solar cell 100.

[0070] In some optional embodiments, continue to refer to Figure 2 and Figure 5 , the size of the solar cell 100 includes 156mm×156mm, 182mm×182mm, 210mm×210mm or 266mm×266mm;

[0071] The number of the back side fine gate lines 2 includes 148, 154, 156, 176, 160, 162, 164, 182 or 200.

[0072] The utility model is applicable to solar cell sheets 100 of various specifications, such as 156mm×156mm, 182mm×182mm, 210mm×210mm or 266mm×266mm. The stripe print can be eliminated by adjusting the spacing between two back fine grid lines 2 at the first edge 3 and / or the second edge 4 and by adjusting the spacing between two back fine grid lines 2 near the half-sheet dividing line 5 so that the back fine grid lines 2 are completely staggered with the front fine grid lines 1.

[0073] In some optional embodiments, the number of the back fine grid lines 2 includes 148, 154, 156, 176, 160, 162, 164, 182 or 200. Optionally, the number of the back fine grid lines 2 is proportional to the size of the solar cell 100. For example, the number of the back fine grid lines 2 in the solar cell 100 of 156mm×156mm specification is 148. Of course, a larger number of back fine grid lines 2 can also be set to improve the ability to collect current. For another example, the number of the back fine grid lines 2 in the solar cell 100 of 210mm×210mm specification is 182. Of course, a larger number of back fine grid lines 2 can also be set to improve the ability to collect current.

[0074] Based on the same inventive concept, the utility model also provides a photovoltaic assembly 200, including the above-mentioned solar cell 100, multiple solar cell 100 form a battery string (not shown in the figure), and also include a first packaging film 21 and a second packaging film 23 located on both sides of the battery string, and a first cover plate 22 located on the side of the first packaging film 21 away from the battery string, and a second cover plate 24 located on the side of the second packaging film 23 away from the battery string.

[0075] Reference Figure 6 , Figure 6It is a schematic diagram of the structure of a photovoltaic module provided by the utility model. The photovoltaic module 200 of this embodiment also includes a first packaging adhesive layer 21 located on the front of the solar cell, a first cover plate 22 located on the side of the first packaging adhesive layer away from the solar cell, a second packaging adhesive layer 23 located on the back of the solar cell, and a second cover plate 24 located on the side of the second packaging adhesive layer 23 away from the solar cell. The front and back sides here are relative. It can be understood that the front side is the direct sunlight side, and the back side is the non-direct sunlight side. The battery string can be formed by connecting multiple solar cells 100 in series, or multiple solar cells 100 in parallel, or multiple solar cells 100 are first connected in series to form a series battery string, and then the series battery string is connected in parallel to form a series-parallel structure. No specific limitation is made here. In the utility model, the first packaging adhesive layer 21 and the second packaging adhesive layer 23 are respectively arranged on the side of the solar cell 100 close to the first cover plate 22 and the second cover plate 24 to encapsulate the solar cell 100. Optionally, the first cover plate 22 may be made of glass, or other light-transmitting materials, and the second cover plate 22 may be made of PET (polyethylene terephthalate) material, or glass, which is not specifically limited here. Figure 1 and Figure 2 The number of solar cells 100 is only for schematic illustration and is not used as the number of solar cells 100 in the actual product. Optionally, the materials of the first encapsulation adhesive layer 21 and the second encapsulation adhesive layer 23 can be EVA (ethylene-vinyl acetate copolymer), POE (ethylene-octene copolymer), EVA and POE integrated co-extruded material, etc., which are not specifically limited here. The photovoltaic module of this embodiment has the beneficial effects of the solar cell of any of the above embodiments, which will not be repeated here.

[0076] It can be seen from the above embodiments that the solar cell and photovoltaic module provided by the utility model achieve at least the following beneficial effects:

[0077] In the prior art, the fine grid lines on the front and back of the solar cell are partially overlapped, and the laser enhanced contact optimization laser power is applied to the overlapped part of the front grid lines and the back grid lines. Since the polysilicon layer on the back is thinner, it is easy to burn through the back, resulting in poor stripe printing of the solar cell. The present application optimizes the fine grid line pattern on the back of the cell. The solar cell of the utility model includes a relative front and back, the front side includes front fine grid lines arranged along a first direction, the back side includes back fine grid lines arranged along the first direction, along the direction perpendicular to the plane where the solar cell is located, the back fine grid lines and the front fine grid lines do not overlap, and the back fine grid lines and the front fine grid lines are completely staggered; along the first direction, the solar cell includes a first edge, a half-piece dividing line, and a second edge, and the half-piece dividing line is located at the midline position of the first edge and the second edge; the half-piece dividing line divides the cell into a first half and a second half, the first edge is located in the first half, and the second edge is located in the second half; the back fine grid lines include edge back fine grid lines, boundary back fine grid lines, and Fine grid lines and evenly distributed back fine grid lines, wherein the spacing between at least two edge back fine grid lines close to the first edge and / or the second edge is a; in the first half sheet and the second half sheet, the spacing between at least two boundary back fine grid lines close to the half-sheet dividing line is b; the spacing between the edge back fine grid lines and the boundary back fine grid lines is evenly distributed back fine grid lines, and the spacing between two adjacent evenly distributed back fine grid lines is c; a<c, b<c, the spacing between the back fine grid lines is not completely evenly divided, ensuring that it is completely staggered with the front fine grid lines. Since the front fine grid lines and the back grid lines do not overlap, when the laser enhanced contact optimization technology is used, the laser hits the front grid lines and will not easily burn through the back side, thereby eliminating the stripe print.

[0078] Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A solar cell, characterized in that: It comprises a front side and a back side opposite to each other, wherein the front side comprises front side fine grid lines arranged along a first direction, and the back side comprises back side fine grid lines arranged along the first direction; Along a direction perpendicular to the plane where the solar cell sheet is located, the back fine grid lines and the front fine grid lines do not overlap; Along the first direction, the solar cell comprises a first edge, a half-cell dividing line and a second edge, the half-cell dividing line is located at a midline position between the first edge and the second edge; the half-cell dividing line divides the cell into a first half cell and a second half cell, the first edge is located in the first half cell, and the second edge is located in the second half cell; The back fine grid lines include edge back fine grid lines, boundary back fine grid lines and uniformly distributed back fine grid lines, wherein: The distance between at least two edge back fine grid lines close to the first edge and / or the second edge is a; In the first half of the sheet and the second half of the sheet, the spacing between at least two boundary back fine grid lines close to the half-sheet dividing line is b; The back fine grid lines between the edge back fine grid lines and the boundary back fine grid lines are uniformly distributed back fine grid lines, and the spacing between two adjacent uniformly distributed back fine grid lines is c; a<c, b<c.

2. The solar cell according to claim 1, characterized in that: The shortest distance between the boundary back fine grid lines of the first half sheet and the boundary back fine grid lines of the second half sheet is d, and 1mm≤d≤1.05mm.

3. The solar cell according to claim 1, characterized in that: a=b.

4. The solar cell according to claim 1, characterized in that: The spacings between the front fine grid lines are all equal, which is equal to the spacing between two adjacent evenly distributed back fine grid lines.

5. The solar cell according to claim 4, characterized in that: Along a direction perpendicular to the plane where the solar cell sheet is located, the back fine grid lines are located between two adjacent front fine grid lines.

6. The solar cell according to claim 5, characterized in that: Along a direction perpendicular to the plane where the solar cell sheet is located, the spacing between the evenly distributed back fine grid lines and two adjacent front fine grid lines is equal to e.

7. The solar cell according to claim 1, characterized in that: The front side also includes a front side border line, and the front side fine grid line is connected to the front side border line; The back side also includes a back side frame line, and the back side fine grid line is connected to the back side frame line; Along a direction perpendicular to the plane where the solar cell is located, the front frame line and the back frame line do not overlap.

8. The solar cell according to claim 1, characterized in that: The total number of the front fine grid lines and the back fine grid lines are equal, and the number of the back fine grid lines is proportional to the size of the solar cell.

9. The solar cell according to claim 8, characterized in that: The size of the solar cell includes 156mm×156mm, 182mm×182mm, 210mm×210mm or 266mm×266mm; The number of the back side fine grid lines includes 148, 154, 156, 176, 160, 162, 164, 182 or 200.

10. A photovoltaic module, characterized in that: The invention comprises a solar cell according to any one of claims 1 to 9, wherein a plurality of said solar cells form a battery string, and further comprises a first packaging film and a second packaging film located on both sides of the battery string, and a first cover plate located on a side of the first packaging film away from the battery string, and a second cover plate located on a side of the second packaging film away from the battery string.

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