Main-grid-free solar cell and photovoltaic module

Abstract

The utility model relates to the technical field of solar cells, and specifically discloses a main-grid-free solar cell and a photovoltaic assembly. The battery piece comprises a battery piece main body and a plurality of merging areas arranged in the battery piece main body, each merging area comprises a plurality of first auxiliary grid lines which extend along a first direction and are arranged at intervals along a second direction, and each merging area comprises a first merging part and a second merging part which are arranged at intervals along the second direction, each of the first merging part and the second merging part is provided with a second auxiliary grid line and an electrode connecting line, the first auxiliary grid line in the same merging part is electrically connected with the electrode connecting line through the second auxiliary grid line, and an enhanced electric connecting line is arranged between the electrode connecting lines of the first merging part and the second merging part for electric connection; the electrode connecting lines and the enhanced electric connecting lines form a current collection area of the first merging part and the second merging part. The electrode connecting lines and the enhanced electric connecting lines are arranged to form a current collection area, so that the welding strips and the fine grid lines form more stable electric contact, and the stability of current conduction is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of solar cells, and specifically discloses a main grid-free solar cell and a photovoltaic module. Background Art

[0002] As the increase in fossil fuel consumption has caused environmental pollution and resource shortages, the demand for renewable energy such as solar energy is increasing day by day. At present, the main goal of the photovoltaic (PV) industry is to reduce the manufacturing cost of solar power generation and improve the power generation efficiency of solar cells. Among solar cell materials, silicon (Si) wafers are the most basic material for manufacturing solar cells and are also the key material for solar cell manufacturing (accounting for about 60% to 70% of the material cost). In addition, the use of silver paste accounts for about 10% of the material cost. In terms of the efficiency of solar cells, the main influencing factors are the structure of the silicon wafer itself and the absorption of incident light by the front surface of the cell. In order to reduce the consumption of silver paste and reduce the shielding of the grid line on the cell, the main grid-free technology came into being.

[0003] The current busbar-free battery eliminates the busbars of the front and back batteries, and directly connects to the secondary grids through welding strips to collect current. When welding the components, the welding strips and the fine grids directly form an alloy contact to achieve the current transmission effect. However, since the fine grid width and welding strip width are very thin, the contact area between the welding strip and the fine grid is small and the current collection capacity is poor. Therefore, busbar-free batteries usually increase the number of welding strips to reduce the current transmission path and improve the current collection capacity.

[0004] Although directly welding thin ribbons is helpful to reduce the shading area, it is difficult to ensure stable electrical contact between the ribbons and the thin grid lines, which will cause certain losses in current collection. In addition, increasing the number of ribbons will inevitably increase the shading area of ​​the cell, which will cause certain power losses of the component and increase the consumption of silver paste.

[0005] For example, patent CN110556442A proposes a main-grid-free crystalline silicon cell and a cell string and solar cell module using the cell, which connects part of the first fine grid lines through the third fine grid lines, but does not directly solve the problem of unstable connection between the welding strip and the fine grid lines. Patent CN212209509U proposes a new main-grid-free battery printing structure. The patent designs the auxiliary grid lines on both sides of the main grid to be trapezoidal or triangular and thickened, in order to ensure the effective transmission area of ​​the component end and the interconnection belt, but the contact problem of welding is not solved. Patent CN220963361U proposes a main-grid-free solar cell and photovoltaic module, which achieves the thickening effect of the welding point by merging multiple auxiliary grids at the welding point to enhance the connection effect. However, the increase in its area will inevitably make the shading area larger, and the consumption of silver paste will be higher, otherwise it is difficult to achieve the effect of improving the stable transmission of the current collected from the fine grid lines.

[0006] It can be seen that how to develop busbar-free solar cells while ensuring welding effects and current transmission stability is a problem that needs to be solved urgently. Utility Model Content

[0007] The purpose of the utility model is to overcome the deficiencies of the prior art and provide a busbar-free solar cell and a photovoltaic module.

[0008] On the one hand, the utility model discloses a busbar-free solar cell, which adopts the following technical solution:

[0009] A busbar-free solar cell comprises a cell body and a plurality of merging regions arranged in the cell body, wherein the merging region comprises a plurality of first secondary grid lines extending along a first direction and arranged at intervals along a second direction, the merging region comprises a first merging portion and a second merging portion arranged at intervals along the second direction, the first merging portion and the second merging portion are both provided with a second secondary grid line and an electrode connecting line, the first secondary grid line in the same merging portion is electrically connected to the electrode connecting line through the second secondary grid line, an enhanced electrical connecting line is provided between the electrode connecting lines of the first merging portion and the second merging portion to be electrically connected, and the electrode connecting line and the enhanced electrical connecting line form a current collection region of the first merging portion and the second merging portion.

[0010] Preferably, a third secondary grid line extending along the first direction is provided on the enhanced electrical connection line.

[0011] Preferably, a third secondary grid line extending along the first direction is provided on the enhanced electrical connection line.

[0012] Preferably, in the same merging area, the distance between two of the electrode connecting lines is smaller than the distance between the two outermost first secondary gate lines.

[0013] Preferably, the first secondary gate lines on two adjacent sides of the current collecting region along the first direction are arranged at intervals.

[0014] Preferably, the intersection of the second secondary gate line and the electrode connection line is 0-90°.

[0015] Preferably, the intersection points of the enhanced electrical connection line and the electrode connection lines of the first merging portion and the second merging portion are on the same straight line.

[0016] Preferably, the intersection points of the first secondary grid lines and the second secondary grid lines are respectively in a straight line in the first direction and the second direction.

[0017] Preferably, the intersection point of the first secondary grid line and the second secondary grid line is arranged in a centrally symmetrical structure with respect to the enhanced electrical connection line.

[0018] Preferably, the first secondary gate line, the second secondary gate line, the electrode connection line and the enhanced electrical connection line have the same width.

[0019] On the other hand, the utility model discloses a photovoltaic assembly, which includes the above-mentioned busbar-free solar cell.

[0020] Compared with the prior art, the utility model has at least the following beneficial effects:

[0021] 1. The utility model divides the fine grid merging area on the battery cell body into a first merging area and a second merging area, and arranges electrode connection lines and enhanced electrical connection lines to form a current collection area, so as to collect the current collected by the fine grids on the first merging area and the second merging area, thereby playing a positioning role during welding and forming multiple welding contact points, so that the welding strip and the fine grid form a stable electrical contact, thereby improving the stability of current conduction;

[0022] 2. Compared with the current conventional battery that forms a current collection point by thickening the grid line, the busbar-free solar cell of the utility model forms a current collection area by forming an electrode connection line and an enhanced electrical connection line, which can withstand a larger current transmission pressure and can achieve a stable current conduction effect without thickening the fine grid, thereby having a relatively smaller shading area, which enables the battery to better collect incident light, and the battery has a smaller consumption of printed silver paste;

[0023] 3. The busbar-free solar cell of the utility model only needs to modify the printed pattern of the front grid line during screen printing. The battery cells still use the original series welding, and the welding machine and welding materials do not need to be changed. This will not increase additional process costs, reduce product costs, and improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1is a schematic diagram of the overall structure of a busbar-free solar cell of this embodiment;

[0025] Figure 2 It is a partial enlarged schematic diagram of the busbar-free solar cell of this embodiment;

[0026] Figure 3 It is a schematic structural diagram of the current collection area of ​​the busbar-free solar cell of this embodiment;

[0027] Figure 4 It is a partial enlarged schematic diagram of the current collection area of ​​the busbar-free solar cell of this embodiment;

[0028] Figure 5 This is a method of a busbar-free solar cell and a welding ribbon in this embodiment;

[0029] Figure 6 This is another method of the busbar-free solar cell and the welding ribbon of this embodiment.

[0030] Description of Figure Numbers:

[0031] 1. Battery cell body; 2. Outer frame line; 3. First secondary grid line; 4. Second secondary grid line; 5. Electrode connection line; 6. Enhanced electrical connection line; 7. Third secondary grid line; 8. Welding strip. DETAILED DESCRIPTION

[0032] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0033] The utility model discloses a main grid-free solar cell. Figure 1 As shown, it mainly includes a battery cell body 1 (including but not limited to TOPcon cells / HJT cells / PERC cells, etc.), the battery cell body 1 includes a silicon wafer, front and back films and a back electric field on the back surface, etc. The battery cell body 1 is a conventional battery. This example takes a TOPcon cell as an example. The battery cell body 1 is subjected to texturing diffusion-wet cleaning-front and back film coating-back electrode printing, and finally a blue film with only the back electrode printed is obtained. The electrodes arranged on the front surface of the battery cell mainly include an outer frame line 2, a first sub-grid line 3, a second sub-grid line 4, an electrode connection line 5 and an enhanced electrical connection line 6. The first sub-grid line 3, the second sub-grid line 4, the electrode connection line 5 and the enhanced electrical connection line 6 constitute a plurality of merged areas. Among them, referring to Figure 2-3 The outer frame line 2 is arranged along the edge of the battery cell body 1 and connected end to end, with the extension direction of the first secondary grid line as the first direction, and the extension direction perpendicular to the first secondary grid line 3 as the second direction. The first secondary grid line 3 is N thin grid lines arranged in parallel with the first direction, and the first secondary grid lines 3 are arranged at intervals in the second direction.

[0034] Reference Figure 3-4 The merging area includes a first merging portion and a second merging portion arranged at intervals along the second direction. The first merging portion and the second merging portion are both provided with a second auxiliary grid line 4 and an electrode connecting line 5. In the same merging portion, the second auxiliary grid line 4 is electrically connected to the first auxiliary grid line 3 and the electrode connecting line 5 respectively, and the electrode connecting lines 5 of the first merging portion and the second merging portion are electrically connected through the enhanced electrical connecting line 6. The electrode connecting line 5 plays a role in conducting the current collected by the second auxiliary grid line 4 into the enhanced electrical connecting line 6, and the electrode connecting line 5 can play a role in strengthening the welding tension during welding. In this way, the electrode connecting line 5 and the enhanced electrical connecting line 6 form a current collection area of ​​the first merging portion and the second merging portion. The setting of this part can collect the current collected by several fine grid lines connected to it. During welding, the welding strip can directly form an electrical connection with the current collection area. The enhanced electrical connecting line 6 will bear the stability of current transmission together with the electrode connecting line 5, which is beneficial to the effective transmission of the battery current, ensuring the welding effect while having good current transmission stability.

[0035] In this embodiment, if Figure 4 As shown, the enhanced electrical connection line 6 is also provided with a third secondary grid line 7 extending along the first direction, and the third secondary grid line 7 is completely through along the first direction. By providing the third secondary grid line 7, the current collection area forms a "W" structure and contacts the welding strip, thereby not only improving the contact problem of welding, but also further ensuring the stable transmission of current. Of course, according to the actual arrangement of the fine grid lines of the battery assembly, a plurality of third secondary grid lines 7 may be provided in a current collection area, or none may be provided.

[0036] In this embodiment, in the same merging area, the distance between the two electrode connection lines 5 is smaller than the distance between the two outermost first secondary grid lines 3, so that the current conduction of multiple first secondary grid lines 3 converges toward the center and the path is shorter, which is conducive to saving slurry.

[0037] In this embodiment, the first secondary gate lines 3 on the adjacent two sides along the first direction in the current collection area are arranged at intervals, that is, the first secondary gate lines 3 are not completely through in the first direction, but are connected to the current collection area through the second secondary gate lines 4, and the first secondary gate lines 3 on both sides of the current collection area are not connected in the first direction, thereby better saving slurry.

[0038] In this embodiment, the intersection of the second secondary grid lines 4 and the electrode connection lines 5 is at a certain angle. Different numbers of the first secondary grid lines 3 will result in different angles, which are generally between 0° and 90°.

[0039] In this embodiment, the enhanced electrical connection line 6 is extended perpendicularly to the first direction, and between adjacent merging areas in the second direction, the intersection points of the enhanced electrical connection line 6 and the electrode connection lines 5 of the first merging part and the second merging part are on the same straight line. In addition, the intersection points of the first auxiliary grid line 3 and the second auxiliary grid line 4 are also in a straight line in the first direction and the second direction, respectively. Figure 5-6 When the assembly is welded, the welding strip forms an electrical connection with the battery cell in the second direction, and the intersection of the welding strip with the electrode connection line 5 and the enhanced electrical connection line 6 is on the same straight line in the second direction, so as to achieve a stable electrical connection between the thin grid line and the welding strip. The intersection of the first secondary grid line 3 and the second secondary grid line 4 is arranged in a central symmetrical structure relative to the enhanced electrical connection line 6, which is conducive to forming a good contact with the welding strip.

[0040] In this embodiment, multiple merging areas are arranged at equal intervals along the first direction, and multiple current collection areas are arranged at equal intervals along the second direction, so that current collection areas arranged in an array of multiple rows and columns are formed on the battery cell. Of course, in other embodiments, it is not limited to the array arrangement, and all reasonable arrangements are acceptable as long as welding and effective current transmission can be guaranteed.

[0041] In the present embodiment, the first secondary grid line 3, the second secondary grid line 4, the third secondary grid line 7, the electrode connection line 5 and the enhanced electrical connection line 6 can all be directly screen-printed on the battery cell by screen printing, and the first secondary grid line 3, the second secondary grid line 4, the third secondary grid line 7, the electrode connection line 5 and the enhanced electrical connection line 6 have the same width (i.e., line thickness), which is 0.01 to 0.05 mm, a conventional fine grid line width. Since the current collection area formed by the electrode connection line 5 and the enhanced electrical connection line 6 can be welded with the welding strip to share the current transmission, good current transmission stability can be achieved without thickening the grid line. Since there is no need to thicken the grid line through multiple printings, it is only necessary to modify the printed pattern of the front grid line during screen printing and directly print it, so that the process steps are simplified and the production cost is reduced. Of course, according to actual needs, the width of the first secondary grid line 3, the second secondary grid line 4, the third secondary grid line 7, the electrode connection line 5 and the enhanced electrical connection line 6 can also be printed to be greater than the width of the conventional fine grid line.

[0042] In this embodiment, the line width (ie, the length along the first direction) of the electrode connection line 5 can be set according to the width of the welding strip, preferably 0.1 mm to 0.3 mm. During welding, the welding strip can directly align with the electrode connection line 5 to perform series welding of the battery cells.

[0043] In addition, the utility model also discloses a photovoltaic module, which comprises front glass, a back plate, an adhesive film and the above-mentioned busbar-free solar cell.

[0044] The technical solution provided by the utility model is introduced in detail above. Specific examples are used in this article to illustrate the principle and implementation mode of the utility model. The description of the above embodiments is only used to help understand the method and core idea of ​​the utility model. At the same time, for general technicians in this field, according to the idea of ​​the utility model, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification should not be understood as a limitation on the utility model.

Claims

1. A busbar-free solar cell, comprising a cell body and a plurality of merging regions arranged in the cell body, wherein the merging regions comprise a plurality of first secondary grid lines extending along a first direction and spaced apart along a second direction, characterized in that: The merging area includes a first merging portion and a second merging portion spaced apart along the second direction, the first merging portion and the second merging portion are both provided with a second sub-gate line and an electrode connecting line, the first sub-gate line in the same merging portion is electrically connected to the electrode connecting line through the second sub-gate line, an enhanced electrical connecting line is provided between the electrode connecting lines of the first merging portion and the second merging portion, and the electrode connecting line and the enhanced electrical connecting line form a current collection area between the first merging portion and the second merging portion.

2. The busbar-free solar cell according to claim 1, characterized in that: A third secondary grid line extending along the first direction is arranged on the enhanced electrical connection line.

3. The busbar-free solar cell according to claim 1, characterized in that: In the same merging area, the distance between two of the electrode connecting lines is smaller than the distance between the two outermost first secondary gate lines.

4. The busbar-free solar cell according to claim 1, characterized in that: The first secondary gate lines on two adjacent sides of the current collecting region along the first direction are arranged at intervals.

5. The busbar-free solar cell according to claim 1, characterized in that: The intersection of the second secondary gate line and the electrode connection line is 0-90 degrees.

6. The busbar-free solar cell according to claim 1, characterized in that: The intersection points of the enhanced electrical connection line and the electrode connection lines of the first merging portion and the second merging portion are on the same straight line.

7. The busbar-free solar cell according to claim 1, characterized in that: The intersection points of the first secondary gate line and the second secondary gate line are respectively in a straight line in the first direction and the second direction.

8. The busbar-free solar cell according to claim 1, characterized in that: The intersection of the first secondary grid line and the second secondary grid line is arranged in a centrally symmetrical structure with respect to the enhanced electrical connection line.

9. The busbar-free solar cell according to claim 1, characterized in that: The first secondary gate line, the second secondary gate line, the electrode connection line and the enhanced electrical connection line have the same width.

10. A photovoltaic module, characterized in that: A busbar-free solar cell comprising the method according to any one of claims 1 to 9.

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