CN217280793U - Solar cell single sheet, solar cell sheet and solar cell - Google Patents

Abstract

The application provides a solar cell monolithic, solar cell piece and solar cell, relates to photovoltaic technical field. The solar cell single chip comprises a plurality of rows of back electrodes arranged on the back surface, each row of back electrodes comprises four main electrodes and a plurality of auxiliary electrodes which are arranged at intervals along a first preset direction, 4-6 auxiliary electrodes which are arranged at intervals are arranged between any two adjacent main electrodes in each row of back electrodes, and the distance between any two adjacent auxiliary electrodes is 30-50 mu m. The solar cell single chip is subjected to bus through the main grid and then transmits current to a nearby back electrode. The solar cell single chip of the application is through quantity, size and the segmentation arrangement mode of the back electrode that changes the back to optimize the transmission path of back electrode and main bars, specifically reduce the distance of main bars to back electrode through the substep, reduce current carrier transmission path, avoid power loss, increase the current carrier and collect, promote filling performance, improve solar cell single chip's photoelectric conversion efficiency.

Description

Solar cell single sheet, solar cell sheet and solar cell

Technical Field

The application relates to the technical field of photovoltaics, in particular to a solar cell single sheet, a solar cell sheet and a solar cell.

Background

At present, the cost of silicon materials in the market of a multi-main-grid assembly rises, the efficiency of a conventional battery reaches the bottleneck, the manufacturing cost is generally increased, the manufacturing pressure is more and more prominent, novel patterns are created, the non-silicon cost is reduced, and the improvement of the battery efficiency is a path which needs to be improved and completed urgently.

At present, the length of an aluminum main grid for connecting two adjacent back electrodes by using a conventional multi-main-grid back graph is longer, a current carrier collected by an aluminum auxiliary grid is transmitted to a silver electrode by the aluminum main grid, and as the resistivity of aluminum is far greater than that of silver, the longer the transmission path of the aluminum main grid is, the larger the transmission resistance is, the current loss is caused, the filling performance is reduced, the efficiency is reduced due to the increase of power loss, and the aim of realizing a high-power component of a battery is not facilitated.

SUMMERY OF THE UTILITY MODEL

An object of the embodiments of the present application is to provide a solar cell monolithic, which can solve the technical problems of long transmission path, large transmission resistance and large current loss of the solar cell.

In a first aspect, an embodiment of the present application provides a solar cell monolithic, a back surface of the solar cell monolithic has a first preset direction, the solar cell monolithic includes a plurality of rows of back electrodes disposed on the back surface, each row of back electrodes includes four main electrodes and a plurality of sub-electrodes spaced along the first preset direction, 4 to 6 sub-electrodes spaced are disposed between any two adjacent main electrodes in each row of back electrodes, and a distance between any two adjacent sub-electrodes is 30 to 50 μm.

The length of the main electrode along the first preset direction is 1.5-3.0 mm, and the length of the auxiliary electrode along the first preset direction is 0.1-0.5 mm.

In the implementation process, the solar cell single chip transmits current to a nearby back electrode after being subjected to bus current through the main grid. The solar cell single chip of the application is through quantity, size and the segmentation arrangement mode of the back electrode that changes the back to optimize the transmission path of back electrode and main bars, specifically reduce the distance of main bars to back electrode through the substep, reduce current carrier transmission path, avoid power loss, increase the current carrier and collect, promote filling performance, improve solar cell single chip's photoelectric conversion efficiency.

Meanwhile, the main electrode is a welding point of the welding strip, the auxiliary electrode only needs to be lapped with the welding strip, and the designed main electrode is larger than the auxiliary electrode, so that the consumption of the raw material of the back electrode can be reduced.

In a possible embodiment, the main electrode includes a first electrode or a second electrode, each column of the back electrodes includes two first electrodes and two second electrodes, the two first electrodes are disposed at two ends of each column of the back electrodes, the two second electrodes are disposed between the two first electrodes, and the length of the first electrodes along the first preset direction is greater than the length of the second electrodes along the first preset direction.

In the implementation process, the two first electrodes arranged at the two ends of each row of back electrodes are used for fixing the welding strips, the size of the welding strips is larger, the size of the second electrode between the two first electrodes is smaller than that of the first battery, the consumption of the back electrode raw materials can be saved, and the cost is reduced.

In a possible embodiment, the length of the first electrode along the first predetermined direction is 2.6 to 3.0mm, and the length of the first electrode along the first predetermined direction is 1.5 to 2.0 mm.

In a possible embodiment, the secondary electrode includes a third electrode or a fourth electrode, each column of the back electrodes includes three third electrodes, the rest are the fourth electrodes, each third electrode is disposed in the middle between two adjacent main electrodes in each column of the back electrodes, and the length of the third electrode along the first preset direction is greater than the length of the fourth electrode along the first preset direction.

In the implementation process, the size of the third electrode arranged in the middle between two adjacent main electrodes in each row of back electrodes is larger than that of the fourth electrode, so that the third electrode can be in lap joint with the welding strip, and convergence and derivation are realized.

In a possible embodiment, the length of the third electrode along the first predetermined direction is 0.3-0.5 mm, and the length of the fourth electrode along the first predetermined direction is 0.1-0.2 mm.

In a possible embodiment, the distance between any two adjacent sub-electrodes in each column of back electrodes is equal.

In a possible embodiment, the back surface of the solar cell single piece further has a second preset direction perpendicular to the first preset direction, a plurality of rows of back electrodes are arranged at intervals along the second preset direction, and the lengths of the main electrodes and the sub-electrodes along the second preset direction are both 2.0-2.12 mm.

In a possible embodiment, the solar cell monolithic further includes a plurality of rows of main grids disposed on the back surface, each row of main grids includes two spaced main grid lines, each row of back electrodes is disposed in one row of main grids, and both ends of each main electrode and each auxiliary electrode are overlapped with the two main grid lines.

In the implementation process, the main grid of the solar cell single sheet can be matched with a sectional back electrode structure, so that the carrier collection is increased, the filling performance is improved, and the photoelectric conversion efficiency of the solar cell single sheet is improved.

In one possible embodiment, the bus bar includes a middle structure and end structures at both ends of the middle structure, and the width of the end structures is greater than that of the middle structure.

In the implementation process, the end structures at the two ends of the main grid line are beneficial to increasing the carrier collection and improving the convergence and leading-out efficiency of the back electrode.

In one possible embodiment, the end structure is trapezoidal or wedge-shaped in shape.

The upper bottom of the end structure is 0.4-0.8 mm, the lower bottom is 0.8-1.6 mm, and the length is 12.5 mm.

The width of the middle structure is 0.3-0.7 mm, and the length is 78.5 mm.

And the upper bottom of the end structure is larger than the width of the middle structure.

In one possible embodiment, the solar cell slice further comprises a plurality of rows of secondary grids arranged on the back surface, each row of secondary grids intersecting a plurality of columns of primary grids.

In a second aspect, the present application provides a solar cell sheet, which includes at least two solar cell monoliths described above.

In the implementation process, the solar cell sheet is formed by splicing or connecting at least two solar cell single sheets.

In a third aspect, embodiments of the present application provide a solar cell, which includes the above solar cell monolithic.

In the implementation process, the solar cell has high photoelectric conversion efficiency.

Drawings

To more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and those skilled in the art can also obtain other related drawings based on the drawings without inventive efforts.

Fig. 1 is a schematic diagram of a back side structure of a conventional multi-master gate battery of the present application;

fig. 2 is a schematic back side structure diagram of a solar cell monolithic according to an embodiment of the present application;

FIG. 3 is a schematic structural diagram of a main electrode according to an embodiment of the present application;

FIG. 4 is a schematic structural diagram of a main gate according to an embodiment of the present application;

fig. 5 is a schematic view of a back side structure of a solar cell according to an embodiment of the present application.

Icon: 10-multiple main gate batteries; 101-an aluminum sub-grid; 102-an aluminum main grid; 103-silver electrode;

20-solar cell single sheet; 21-a first preset direction; 22-a second preset direction; 200-a back electrode; 210-a first electrode; 220-a second electrode; 230-a third electrode; 240-fourth electrode; 300-a main gate; 310-main grid line; 400-secondary grid; and 30-solar cell piece.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present application, it should be noted that the terms "upper", "lower", and the like refer to orientations or positional relationships based on orientations or positional relationships shown in the drawings or orientations or positional relationships that the products of the application usually place when using, are only used for convenience of description and simplification of description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present application. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

In the description of the present application, it is also to be noted that, unless otherwise explicitly specified or limited, the terms "disposed" and "connected" are to be interpreted broadly, e.g., as being either fixedly connected, detachably connected, or integrally connected; either mechanically or electrically. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

Referring to fig. 1, a back surface field of a conventional multi-main-gate battery 10 is formed by aluminum sub-gates 101 which are uniformly distributed in a horizontal direction and in parallel and aluminum main gates 102 which are parallel in a longitudinal direction and in equal intervals, the aluminum sub-gates 101 and the aluminum main gates 102 are perpendicularly intersected, the aluminum sub-gates 101 are in contact with a silicon substrate through laser grooving holes and collect carriers, so that formation current is collected onto the aluminum main gates 102, the aluminum sub-gates 101 and the aluminum main gates 102 are connected with silver electrodes 103 in a distributed overprint manner, and finally the aluminum sub-gates 101 and the aluminum main gates 102 are connected with solder strips through the silver electrodes 103 and led out.

In the back field of the conventional multi-main-grid battery 10, the length of the aluminum main grid 102 connecting two adjacent back electrodes 200 is relatively long, carriers collected by the aluminum auxiliary grid 101 are transmitted to the silver electrode 103 and then pass through the aluminum main grid 102, and as the resistivity of aluminum is much larger than that of silver, the longer the transmission path of the aluminum main grid 102 is, the transmission resistance is increased, the current loss is caused, the filling performance is reduced, and the efficiency is reduced due to the increase of power loss.

Referring to fig. 2, the present application provides a solar cell sheet 20 having a back surface with a first predetermined direction 21 and a second predetermined direction 22 perpendicular to each other.

The solar cell single sheet 20 includes a plurality of rows of back electrodes 200 disposed on the back surface, and the plurality of rows of back electrodes 200 are spaced along the second predetermined direction 22.

Alternatively, the pitches between any two adjacent columns of the back electrodes 200 are equal.

Optionally, the distance between any two adjacent columns of back electrodes 200 is 17.45 mm.

Each column of back electrodes 200 comprises four main electrodes and a plurality of auxiliary electrodes which are arranged at intervals along the first preset direction 21, 4-6 auxiliary electrodes which are arranged at intervals are arranged between any two adjacent main electrodes in each column of back electrodes 200, and the distance between any two adjacent auxiliary electrodes is 30-50 μm.

The main electrode and the auxiliary electrode are both rectangular, the length of the main electrode along the first preset direction 21 is 1.5-3.0 mm, and the length of the auxiliary electrode along the first preset direction 21 is 0.1-0.5 mm.

It should be noted that the number of the sub-electrodes disposed between two adjacent main electrodes may be the same or different. For example, the number of the auxiliary electrodes arranged between any two adjacent main electrodes may be 4, 5 or 6; or the number of the sub-electrodes provided between the first main electrode and the second main electrode may be 5, and the number of the sub-electrodes provided between the second main electrode and the third main electrode may be 6.

In the embodiment shown in fig. 2, the pitch between any two adjacent sub-electrodes is 40 μm. In some other embodiments of the present application, the spacing between any two adjacent secondary electrodes may be 30 μm, 32 μm, 34 μm, 36 μm, 38 μm, 42 μm, 44 μm, 46 μm, 48 μm, or 50 μm.

Alternatively, the spacing between any two adjacent sub-electrodes in each column of the back electrode 200 is equal.

Alternatively, the pitch between any two adjacent sub-electrodes in each column of the back electrodes 200 is 40 μm.

Referring to fig. 3, in the embodiment shown in fig. 3, the main electrode includes a first electrode 210 or a second electrode 220, and each column of the back electrodes 200 includes two first electrodes 210 and two second electrodes 220.

The first electrodes 210 are disposed at two ends of each row of the back electrodes 200, and the two second electrodes 220 are disposed between the two first electrodes 210.

The length of the first electrode 210 along the first predetermined direction 21 is 2.6-3.0 mm, and the length of the first electrode 210 along the second predetermined direction 22 is 2.0-2.12 mm.

In the embodiment shown in fig. 3, the length of the first electrode 210 along the first predetermined direction 21 is 2.8mm, and the length of the first electrode 210 along the second predetermined direction 22 is 2.06 mm. In some other embodiments of the present application, the length of the first electrode 210 along the first preset direction 21 may also be 2.6mm, 2.7mm, 2.9mm or 3.0mm, and the length of the first electrode 210 along the second preset direction 22 may also be 2.0mm, 2.01mm, 2.02mm, 2.03mm, 2.04mm, 2.05mm, 2.07mm, 2.08mm, 2.09mm, 2.1mm, 2.11mm or 2.12 mm.

The length of the second electrode 220 along the first predetermined direction 21 is 1.5-2.0 mm, and the length of the second electrode 220 along the second predetermined direction 22 is 2.0-2.12 mm.

In the embodiment shown in fig. 3, the length of the second electrode 220 along the first predetermined direction 21 is 1.8mm, and the length of the second electrode 220 along the second predetermined direction 22 is 2.06 mm. In some other embodiments of the present application, the length of the second electrode 220 along the first preset direction 21 may also be 1.5mm, 1.6mm, 1.7mm, 1.9mm or 2.0mm, and the length of the second electrode 220 along the second preset direction 22 may also be 2.0mm, 2.01mm, 2.02mm, 2.03mm, 2.04mm, 2.05mm, 2.07mm, 2.08mm, 2.09mm, 2.1mm, 2.11mm or 2.12 mm.

The two first electrodes 210 disposed at the two ends of each row of the back electrode 200 are used for fixing the solder strip, and the size of the second electrode 220 between the two first electrodes 210 is smaller than that of the first battery, so that the consumption of the raw material of the back electrode 200 can be reduced, and the cost can be reduced.

Referring to fig. 3, in the embodiment shown in fig. 3, the sub-electrodes include third electrodes 230 or fourth electrodes 240, each column of the back electrodes 200 includes three third electrodes 230, and the rest are the fourth electrodes 240.

Wherein each third electrode 230 is disposed in the middle between two adjacent main electrodes in each column of the back electrodes 200.

The length of the third electrode 230 along the first predetermined direction 21 is 0.3-0.5 mm, and the length of the third electrode 230 along the second predetermined direction 22 is 2.0-2.12 mm.

In the embodiment shown in fig. 3, the length of the third electrode 230 along the first predetermined direction 21 is 0.5mm, and the length of the third electrode 230 along the second predetermined direction 22 is 2.06 mm. In some other embodiments of the present application, the length of the third electrode 230 along the first preset direction 21 may also be 0.3mm or 0.5mm, and the length of the third electrode 230 along the second preset direction 22 may also be 2.0mm, 2.01mm, 2.02mm, 2.03mm, 2.04mm, 2.05mm, 2.07mm, 2.08mm, 2.09mm, 2.1mm, 2.11mm or 2.12 mm.

The length of the fourth electrode 240 along the first predetermined direction 21 is 0.1-0.2 mm, and the length of the fourth electrode 240 along the second predetermined direction 22 is 2.0-2.12 mm.

In the embodiment shown in fig. 3, the length of the fourth electrode 240 along the first preset direction 21 is 0.15mm, and the length of the fourth electrode 240 along the second preset direction 22 is 2.06 mm. In some other embodiments of the present application, the length of the fourth electrode 240 along the first preset direction 21 may also be 0.1mm or 0.2mm, and the length of the fourth electrode 240 along the second preset direction 22 may also be 2.0mm, 2.01mm, 2.02mm, 2.03mm, 2.04mm, 2.05mm, 2.07mm, 2.08mm, 2.09mm, 2.1mm, 2.11mm, or 2.12 mm.

The third electrode 230 disposed in the middle between two adjacent main electrodes in each row of the back electrodes 200 is larger in size than the fourth electrode 240, and can be ensured to overlap with the solder strip, so that the bus bar is led out.

Optionally, the lengths of the first electrode 210, the second electrode 220, the third electrode 230 and the fourth electrode 240 along the second preset direction 22 are equal.

Optionally, 1-6 fourth electrodes 240 are further disposed on a side of the first electrode 210 away from the second electrode 220 in each column of the back electrodes 200.

In the embodiment shown in fig. 3, each solar cell sheet 20 includes 12 columns of back electrodes 200 sequentially spaced along the second predetermined direction 22, and each column of back electrodes 200 sequentially includes, from top to bottom, 3 fourth electrodes 240, 1 first electrode 210, 3 fourth electrodes 240, 1 third electrode 230, 2 fourth electrodes 240, 1 second electrode 220, 2 fourth electrodes 240, 1 fourth electrode 240, 1 third electrode 230, 3 fourth electrodes 240, 1 first electrode 210, and 3 fourth electrodes 240.

With reference to fig. 1, the solar cell monolithic 20 further includes a plurality of rows of main grids 300 disposed on the back surface, each row of main grids 300 includes two spaced main grid lines 310, each main grid line 310 is disposed along the first predetermined direction 21, each row of back electrodes 200 is disposed in one row of main grids 300, that is, between two main grid lines 310, two ends of each main electrode and each auxiliary electrode are connected to the two main grid lines 310, and the plurality of rows of main grids 300 and the plurality of rows of back electrodes 200 are disposed in one-to-one correspondence.

Alternatively, both ends of each of the main and sub electrodes are overlapped with two bus bars 310 but not more than two bus bars 310.

Optionally, the overlapping length of each end of each main electrode and each auxiliary electrode is 0.1-0.13 mm.

In the embodiment shown in fig. 1, the overlapping length of each end of each of the main electrode and the sub-electrode is 0.1 mm. In other embodiments of the present application, the overlapping length of each end of each of the main and sub electrodes may also be 0.11mm, 0.12mm, or 0.13 mm.

Referring to fig. 4, in the embodiment shown in fig. 4, each bus bar 310 includes a middle structure and end structures located at two ends of the middle structure, and the width of the end structures is greater than that of the middle structure, that is, the length of the end structures along the first predetermined direction is greater than that of the middle structure along the first predetermined direction.

Optionally, the end structures are trapezoidal or wedge shaped, and the upper base of the end structures is greater than the width of the middle structure.

The upper bottom of the end structure is 0.4-0.8 mm, the lower bottom is 0.8-1.6 mm, and the length is 12.5 mm.

In the embodiment shown in figure 4, the end structure has an upper base of 0.6mm, a lower base of 1.2mm and a length of 12.5 mm. In other embodiments of the present application, the upper base of the end structure may also be 0.4mm, 0.5mm, 0.7mm or 0.8mm, and the lower base may also be 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.3mm, 1.4mm, 1.5mm or 1.6 mm.

The width of the middle structure is 0.3-0.7 mm, and the length is 78.5 mm.

In the embodiment shown in fig. 4, the width of the central structure is 0.5mm and the length is 78.5 mm. In other embodiments of the present application, the width of the central structure may also be 0.3mm, 0.4mm, 0.6mm, or 0.7 mm.

The end structures at the two ends of the main gate line 310 of the present application are beneficial to increasing carrier collection and improving the bus bar derivation efficiency of the back electrode 200.

With continued reference to fig. 1, the solar cell sheet 20 further includes a plurality of rows of sub-grids 400 disposed on the back surface, the plurality of rows of sub-grids 400 are arranged at intervals along the first predetermined direction 21, each row of sub-grids 400 extends along the second predetermined direction 22, and each row of sub-grids 400 intersects with the plurality of rows of main grids 300.

The width of the sub-grid 400 is 0.1-0.25 mm.

In the embodiment shown in fig. 1, the width of the sub-gate 400 is 0.1 mm. In other embodiments of the present application, the width of the sub-gate 400 may also be 0.15mm, 0.2mm, or 0.25 mm.

Alternatively, the pitches between any two adjacent rows of the sub-gates 400 are equal.

The distance between any two adjacent rows of the auxiliary grids 400 is 0.8-1.5 mm.

In the embodiment shown in fig. 1, the spacing between any two adjacent rows of sub-gates 400 is 1.06 mm. In other embodiments of the present application, the spacing between any two adjacent rows of the sub-grids 400 may also be 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, or 1.5 mm.

The sub-grid 400 is contacted with the silicon substrate through the laser slotted holes and collects current carriers, and the current carriers are transversely collected and then converged to the main grid 300 and are led out through the connection of the back electrode 200 and the solder strip.

The solar cell single sheet 20 of the application optimizes the transmission paths of the back electrode 200 and the main grid 300 by changing the number, size and sectional arrangement mode of the back electrode 200 at the back, particularly reduces the distance from the main grid 300 to the back electrode 200 step by step, enables the main grid 300 to be matched with a sectional type back electrode 200 structure, reduces the transmission path of current carriers, avoids power loss, increases the collection of current carriers, improves the filling performance and improves the photoelectric conversion efficiency of the solar cell single sheet 20. Meanwhile, the main electrode is a welding point of the welding strip, the auxiliary electrode only needs to be lapped with the welding strip, and the designed main electrode is larger than the auxiliary electrode, so that the consumption of the raw material of the back electrode 200 can be reduced.

The solar cell single sheet 20 adopts a high-precision process, ensures that the whole size is 10% smaller than that of a conventional multi-main grid 300 after the lapping, reduces the unit consumption of back silver by 6-12 mg, and greatly reduces the cost of back silver.

The preparation method of the solar cell single piece comprises the following steps of taking a single crystal P-type silicon wafer as an example:

s1, texturing: a monocrystal P-type silicon wafer is adopted, and front and back texturing is carried out by alkali to form a textured structure.

S2, diffusion: and (3) reacting the silicon wafer after texturing with phosphorus oxychloride at high temperature to diffuse the front side to form a PN emitter junction. The sheet resistance of the front surface thin layer after diffusion is 165-170 omega/sq.

S3, laser SE: and performing laser doping on the front surface of the diffused silicon wafer and the metalized area corresponding to the positive electrode grid line by using the diffused phosphorosilicate glass as a phosphorus source to form a heavily doped area, so that the structure of the selective emitter is realized on the front surface of the silicon wafer, and the square resistance of the heavily doped area is 80-90 omega/sq.

S4, hot oxygen: and introducing oxygen into the silicon wafer after the laser SE for oxidation.

S5, removing PSG: and (4) removing the PSG on the back surface and the periphery of the silicon wafer after thermal oxidation by using HF.

S6, alkali polishing: and polishing the back and the edge of the silicon wafer after the PSG is removed, and removing the PSG on the front side.

S7, oxidation annealing: and carrying out oxidation and annealing treatment on the silicon wafer subjected to alkali polishing.

S8, depositing a passivation film: and preparing a passivation film on the back of the annealed silicon wafer, and preparing a passivation and antireflection layer on the front of the silicon wafer.

S9, back laser: and laser grooving is carried out on the positions, corresponding to the aluminum auxiliary grid region and the aluminum main grid region, of the back electric field by adopting a laser grooving pattern corresponding to the aluminum electric field. The silver electrode area is not grooved by laser, and the specification of the non-grooved area is determined according to the design specification of the silver electrode.

S10, back silver electrode: and (3) adopting a screen printing mode, selecting silver paste on the silicon chip subjected to back laser grooving, printing a back electrode, and controlling the wet weight of the back silver of the single chip to be 30-33 mg.

S11, preparing a back electric field: selecting aluminum paste, adopting a screen plate with 360 meshes, 16 mu m of wire diameter, 28 mu m of sand thickness and 18 mu m of film thickness, and synchronously printing an aluminum main grid and an aluminum auxiliary grid according to a design pattern in a screen printing mode.

S12, printing a positive electrode main grid region: and adopting front silver paste to prepare the front electrode on the silicon wafer printed with the back electrode by screen printing.

S13, printing a front side sub-grid region: and printing the front side secondary grid by adopting front silver paste according to the screen pattern.

S14, sintering: and (3) co-sintering the silicon wafer with the front electrode printed, wherein the sintering peak temperature is 780 ℃.

S15, electric injection: and carrying out electro-injection treatment on the sintered cell.

S16, finished product: and testing, sorting, packaging and warehousing the product battery pieces.

According to the preparation method of the solar cell single sheet, under the condition that the performances of welding the back shading area assembly and the like are not negatively influenced, the printing of the slurry is effectively guaranteed, the quantity of broken grids of the back electrode during printing is reduced, the EL of the assembly end is improved, and the printing quality and the production efficiency are improved.

Referring to fig. 5, the present application further provides a solar cell 30, which includes at least two solar cell sheets 20 as described above.

The solar cell sheet 30 is formed by splicing or connecting at least two solar cell single sheets 20.

The embodiment of the present application provides a solar cell, which includes the solar cell slice 20. The solar cell has high photoelectric conversion efficiency.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims (13)

1. The solar cell single sheet is characterized in that the back surface of the solar cell single sheet is provided with a first preset direction, the solar cell single sheet comprises a plurality of rows of back electrodes arranged on the back surface, each row of back electrodes comprises four main electrodes and a plurality of auxiliary electrodes which are arranged at intervals along the first preset direction, 4-6 auxiliary electrodes which are arranged at intervals are arranged between any two adjacent main electrodes in each row of back electrodes, and the distance between any two adjacent auxiliary electrodes is 30-50 mu m;

the length of the main electrode along the first preset direction is 1.5-3.0 mm, and the length of the auxiliary electrode along the first preset direction is 0.1-0.5 mm.

2. The solar cell tile of claim 1, wherein the main electrode comprises a first electrode or a second electrode, each column of the back electrodes comprises two first electrodes and two second electrodes, the two first electrodes are disposed at two ends of each column of the back electrodes, the two second electrodes are disposed between the two first electrodes, and the length of the first electrodes along the first predetermined direction is greater than the length of the second electrodes along the first predetermined direction.

3. The solar cell slice as claimed in claim 2, wherein the first electrode has a length along the first predetermined direction of 2.6-3.0 mm, and the second electrode has a length along the first predetermined direction of 1.5-2.0 mm.

4. The solar cell slice as claimed in any one of claims 1 to 3, wherein the secondary electrode comprises a third electrode or a fourth electrode, each column of the back electrodes comprises three third electrodes, the rest are the fourth electrodes, each third electrode is disposed in the middle between two adjacent main electrodes in each column of the back electrodes, and the length of the third electrode in the first predetermined direction is greater than the length of the fourth electrode in the first predetermined direction.

5. The solar cell slice as claimed in claim 4, wherein the third electrode has a length along the first predetermined direction of 0.3-0.5 mm, and the fourth electrode has a length along the first predetermined direction of 0.1-0.2 mm.

6. The solar cell monolith of claim 1, wherein any two adjacent sub-electrodes in each column of the back electrodes are equally spaced.

7. The solar cell slice as claimed in claim 1, wherein the back surface of the solar cell slice further has a second predetermined direction perpendicular to the first predetermined direction, the plurality of rows of back electrodes are arranged at intervals along the second predetermined direction, and the lengths of the main electrodes and the sub-electrodes along the second predetermined direction are both 2.0-2.12 mm.

8. The solar cell tile of claim 1, further comprising a plurality of rows of primary grids disposed on the back side, each row of primary grids comprising two spaced primary grid lines, each row of back electrodes disposed in one row of primary grids, and each primary electrode and each secondary electrode having two ends overlapping two primary grid lines.

9. The solar cell tile of claim 8, wherein the bus bar comprises a central structure and end structures at opposite ends of the central structure, the end structures having a width greater than a width of the central structure.

10. The solar cell monolith of claim 9, wherein the end structures are trapezoidal or wedge shaped;

the upper bottom of the end structure is 0.4-0.8 mm, the lower bottom of the end structure is 0.8-1.6 mm, and the length of the end structure is 12.5 mm;

the width of the middle structure is 0.3-0.7 mm, and the length of the middle structure is 78.5 mm;

and the upper bottom of the end structure is larger than the width of the middle structure.

11. The solar cell tile of claim 8, further comprising a plurality of rows of secondary grids disposed on the back surface, each row of secondary grids intersecting a plurality of columns of the primary grids.

12. A solar cell sheet, comprising at least two solar cell sheets according to any one of claims 1 to 11.

13. A solar cell comprising the solar cell sheet according to any one of claims 1 to 11.

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