(19)
(11)EP 3 614 443 A1

(12)EUROPEAN PATENT APPLICATION
published in accordance with Art. 153(4) EPC

(43)Date of publication:
26.02.2020 Bulletin 2020/09

(21)Application number: 17906291.4

(22)Date of filing:  10.08.2017
(51)Int. Cl.: 
H01L 31/0224  (2006.01)
(86)International application number:
PCT/CN2017/000517
(87)International publication number:
WO 2018/191831 (25.10.2018 Gazette  2018/43)
(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
Designated Extension States:
BA ME
Designated Validation States:
MA MD

(30)Priority: 20.04.2017 CN 201710260382

(71)Applicant: Jolywood (Taizhou) Solar Technology Co., Ltd.
Taizhou, Jiangsu 225500 (CN)

(72)Inventors:
  • LIN, Jianwei
    Taizhou, Jiangsu 225500 (CN)
  • LIU, Zhifeng
    Taizhou, Jiangsu 225500 (CN)
  • JI, Genhua
    Taizhou, Jiangsu 225500 (CN)
  • LIU, Yong
    Taizhou, Jiangsu 225500 (CN)

(74)Representative: Plasseraud IP 
66, rue de la Chaussée d'Antin
75440 Paris Cedex 09
75440 Paris Cedex 09 (FR)

  


(54)DENSELY-ARRANGED SOLAR CELL STRING AND PREPARATION METHOD, AND ASSEMBLY AND SYSTEM THEREOF


(57) The present application relates to a densely-arranged solar cell string and a preparation method thereof, a solar cell module and a solar cell system. The preparation method of the present application mainly comprises the following steps: preparing a solar cell, and forming H-type electrodes on front and back surfaces of the cell, wherein main grids are segmented electrodes and welding points are arranged at ends of the main grids; printing a strip-shaped hot melt adhesive at the welding points in a direction perpendicular to the main grids, and exposing the welding points from the hot melt adhesive; cutting, along a cell cutting region, the cell into a plurality of small cells; coating an conductive adhesive or solder paste at the main grid welding points on front surfaces of the small cells; superposing main grid welding points on a back surface of one small cell onto main grid welding points on a front surface of another small cell, and heating so that the two small cells are electrically connected through the conductive adhesive or solder paste; and, successively connecting the plurality of small cells to form a solar cell string. The present application has the following beneficial effects: the utilization area of cells in an effective region of a module is increased, and the power of the module is improved.




Description

TECHNICAL FIELD



[0001] The present application relates to the technical field of solar cells and in particular to a densely-arranged solar cell string and a preparation method thereof, a solar cell module and a solar cell system.

BACKGROUND



[0002] Solar cell modules are photovoltaic power generation units that convert light energy into electrical energy. Low production cost and high energy conversion efficiency have always been the goal pursued by the solar cell modules. For a conventional solar cell module, among the cells in the module, a cathode of a cell and an anode of another cell are connected to form a solar cell string. Then, a front layer material, a packaging material, the solar cell string, the packing material and a back layer material are laminated to form the solar cell module. In the process of connecting the cells in series, since the cathode and anode of the cell are located on two sides of the cell, respectively, the electrode on a front surface of a cell needs to be connected to the electrode on a back surface of an adjacent cell by welding. Since the welding strip has a certain thickness, a certain gap used for releasing for the shearing force needs to be reserved between the cells connected in series, in order to avoid the breakage of the cells. Generally, the gap between the cells is 1 to 3 mm. Since there are no cells in the gap region, the power of the module will certainly be lost.

[0003] CN104919597A has disclosed a method for configuring a cell string, wherein "the cell string body includes at least one cell string; the cell string includes a plurality of arranged crystalline silicon cells; and, a front surface of a next crystalline silicon cell and a back surface of a previous crystalline silicon cell are stacked to form an electrical connection". This solution can increase the utilization area of cells in an effective region of the module and improve the power of the module. However, the solution has the following disadvantages: 1) in the solution disclosed therein, main grid lines are perpendicular to the series-connection of the cells, and the current can be collected only after passing through fine grid lines and then flowing into welding points; and, 2) adjacent cells are connected by a conductive adhesive, so some problems may occur in the mechanical strength and the connection firmness during the actual production process.

SUMMARY



[0004] An objective of the present application is to provide a densely-arranged solar cell string and a preparation method thereof, a solar cell module and a solar cell system. According to the method for preparing a densely-arranged solar cell string provided by the present application, no gap is generated between cells during the series-connection process, so that the utilization area of cells in an effective region of a module is increased and the power of the module is improved.

[0005] The present application provides a method for preparing a densely-arranged solar cell string. The technical solution will be described below. The method includes the following steps:
  1. (1) preparing a solar cell, wherein main grids and fine grids of the solar cell are perpendicular to each other; the main grids are segmented electrodes, and welding points for electrical connection between cells are arranged at ends of the segmented main grids; the positions of the main grid welding points on the back surface and the positions of the main grid welding points on the front surface are symmetrical about a center; and, a cell cutting region is further provided on the solar cell, and the cell cutting region is perpendicular to the main grids;
  2. (2) printing a strip-shaped hot melt adhesive: printing the strip-shaped hot melt adhesive at the welding points of the segmented main grids in a direction perpendicular to the main grids;
  3. (3) cutting the cell: cutting, along the cell cutting region, the solar cell into a plurality of small cells;
  4. (4) coating a conductive adhesive or solder paste: coating the conductive adhesive or solder paste at the main grid welding points on the front surfaces of the small cells;
  5. (5) adhering the small cells: superposing main grid welding points on a back surface of one small cell onto main grid welding points on a front surface another small cell, and heating so that the two small cells are electrically connected through the conductive adhesive or solder paste; and, melting the hot melt adhesive while heating, and solidifying the hot melt adhesive after cooling, so that the two small cells are closely adhered together and the welding points on the two small cells form firm ohmic contact; and
  6. (6) repeating the step (5) for the plurality of small cells so that the plurality of small cells are successively connected to form a solar cell string.


[0006] Wherein, there are 3 to 15 main grids each having a width of 100 to 1200 µm.

[0007] Wherein, the cell cutting region has a width of 1 to 2 mm; the hot melt adhesive has a width of 1 to 3 mm, and the welding points are exposed from the hot melt adhesive; and, the hot melt adhesive needs to be dried at a temperature of below 150°C after printed.

[0008] Wherein, in the step (3), the cutting is laser cutting.

[0009] Wherein, in the step (5), the heating is resistance wire heating or infrared heating.

[0010] Another aspect of the present application provides a densely-arranged solar cell string, including solar cell units, wherein fine grids, main grids and main grid welding points are provided on front and back surfaces of the solar cell units, and the main grid welding points are arranged at ends of the main grids; a hot melt adhesive is coated on the front surfaces of the solar cell units along a direction of the fine grids, the hot melt adhesive is disconnected in a region of the main grid welding points, and a conductive adhesive or solder paste is coated at the main grid welding points; the back surface of one solar cell unit is superposed onto the front surface of another solar cell unit along a long-side direction, and the width of an superposed region of the two solar cell units is the width of the main grid wielding points; and, the main welding points on the back surface of one solar cell unit come into ohmic contact with the main grid welding points on the front surface on another solar cell unit through the conductive adhesive or solder paste, so that the two solar cell units are adhered together through the hot melt adhesive.

[0011] Wherein, electrodes on the back and front surfaces of the solar cell units are H-type electrodes, and the main grids and the fine grids are perpendicular to each other.

[0012] Wherein, the hot melt adhesive has a width of 1 to 3 mm.

[0013] Still another aspect of the present application provides a densely-arranged solar cell module, including a front layer material, a packaging material, a solar cell string, the packaging material and a back layer material which are successively arranged from the top down, the solar cell string being the solar cell string described above.

[0014] Yet another aspect of the present application provides a solar cell system, including at least one solar cell module connected in series, wherein the solar cell module is the solar cell module described above.

[0015] The present application have the following beneficial effects.

[0016] The technical advantages of the present application are mainly embodied as follows:
  1. 1) two adjacent cells are closely adhered by a hot melt adhesive, so the mechanical strength and firm ohmic contact of the welding points are ensured, and the hot melt adhesive can also prevent the flow of the conductive adhesive; 2) the cell is in an H-type grid line design, and the main grids are parallel to the series-connection direction of the cell, so this configuration can significantly improve the current collection efficiency; 3) since the conductive adhesive is only coated at the main grid welding points, the amount of the conductive adhesive is saved; and, 4) since no gap is generated between cells during the series-connection process, the utilization area of cells in an effective region of a module is increased and the power of the module is improved.

BRIEF DESCRIPTION OF THE DRAWINGS



[0017] 

Fig. 1 is a diagram of a cell structure after step 1 in a method for preparing a densely-arranged solar cell string according to an embodiment of the present application;

Fig. 2 is a diagram of a cell structure after step 2 in the method for preparing a densely-arranged solar cell string according to an embodiment of the present application;

Fig. 3 is a diagram of a cell structure after step 3 in the method for preparing a densely-arranged solar cell string according to an embodiment of the present application;

Fig. 4 is a diagram of a cell structure after step 4 in the method for preparing a densely-arranged solar cell string according to an embodiment of the present application;

Fig. 5 is a diagram of a cell structure after step 5 in the method for preparing a densely-arranged solar cell string according to an embodiment of the present application; and

Fig. 6 is a diagram of a cell structure after step 6 in the method for preparing a densely-arranged solar cell string according to an embodiment of the present application.


DETAILED DESCRIPTION



[0018] The present application will be described below in detail with reference to the accompanying drawings by embodiments. It is to be noted that the embodiments to be described are merely provided for understanding of the present application and not intended to limit the present application.

[0019] Referring to Figs. 1-6, a method for preparing a densely-arranged solar cell string in this embodiment includes the following steps.
  1. (1) Preparing a solar cell: as shown in Fig. 1, electrodes on the front surface are H-type electrodes. Main grids 11 and fine grid lines 10 are perpendicular to each other, wherein the main grids 11 are segmented, and welding points used for electrical connection between cells are arranged at ends of the segmented main grids. There are 3 to 15 main grids 11 each having a width of 100 to 1200 µm. Meanwhile, a cell cutting region 12 is provided. The cutting region 12 is perpendicular to the main grids 11, and has a width of 1 to 2 mm. The electrode structure on the back surface of the cell is also H-type electrodes, main grids are segmented, and welding points are arranged at ends of the segmented main grids. The positions of the welding points on the back surface and the positions of the welding points on the front surface are symmetrical about a center.
  2. (2) Printing a strip-shaped hot melt adhesive 13: the strip-shaped hot melt adhesive 13 is printed at the welding points of the segmented main grids in a direction perpendicular to the main grids, but the welding points need to be exposed. The hot melt adhesive has a width of 1 to 3 mm. The hot melt adhesive needs to be dried at a temperature of below 150°C after printed.
  3. (3) Cutting the cell: along the cell cutting region 12, the cell is cutting into a plurality of small cells, as shown in Fig. 2. As shown Fig. 3, the cutting is preferably laser cutting.
  4. (4) A conductive adhesive or solder paste 14 is located at the main grid lines 11 on the front surface of the cell. As shown in Fig. 14, the conductive adhesive or solder paste is not coated at the welding points on the back surface of the cell.
  5. (5) As shown in Fig. 5, two small cells are adhered, wherein main grid welding points on a back surface of one small cell are superposed onto main grid welding points on a front surface of another small cell, and the two small cells are heated by in a resistance wire heating manner or an infrared heating manner, so that the two small cells are electrically connected through the conductive adhesive or solder paste 14. The hot melt adhesive is molten while heating, and then solidified after cooling, so that the two small cells are closely adhered together to ensure firm ohmic contact of the welding points of the two cells.
  6. (6) As shown in Fig. 6, the step (5) is repetitively executed for the plurality of small cells, so that the plurality of small cells are successively connected to form a solar cell string.


[0020] In the present application, two adjacent cells are closely adhered by a hot melt adhesive, so the mechanical strength and firm ohmic contact of the welding points are ensured, and the hot melt adhesive can also prevent the flow of the conductive adhesive; 2) the cell is in an H-type grid line design, and the main grids are parallel to the series-connection direction of the cell, so this configuration can significantly improve the current collection efficiency; 3) since the conductive adhesive is only coated at the main grid welding points, the amount of the conductive adhesive is saved; and, 4) since no gap is generated between cells during the series-connection process, the utilization area of cells in an effective region of a module is increased and the power of the module is improved.

[0021] This embodiment further provides a densely-arranged solar cell string, including solar cell units. Fine grids 10, main grids 11 and main grid welding points are provided on front and back surfaces of the solar cell units, and the main grid welding points are arranged at ends of the main grids 11. A hot melt adhesive 13 is coated on the front surfaces of the solar cell units along a direction of the fine grids 10, the hot melt adhesive 13 is disconnected in a region of the main grid welding points, and a conductive adhesive or solder paste 14 is coated at the main grid welding points. The back surface of one solar cell unit is superposed onto the front surface of another solar cell unit along a long-side direction. The width of an superposed region of the two solar cell units is the width of the main grid wielding points. The main welding points on the back surface of one solar cell unit come into ohmic contact with the main grid welding points on the front surface on another solar cell unit through the conductive adhesive or solder paste 14, so that the two solar cell units are adhered together through the hot melt adhesive 13.

[0022] Preferably, electrodes on the front and back surfaces of the solar cell are H-type electrodes, and the main grids and the fine grids are perpendicular to each other.

[0023] Preferably, the hot melt adhesive has a width of 1 to 3 mm.

[0024] This embodiment further provides a densely-arranged solar cell module, including a front layer material, a packaging material, a solar cell string, the packaging material and a back layer material which are successively arranged from the top down, the solar cell string being the solar cell string described above.

[0025] This embodiment further provides a solar cell system, including at least one solar cell module connected in series, wherein the solar cell module is the solar cell module described above.

[0026] At last, it should be noted that the embodiments described above are merely provided to explain the technical solution of the present application, not to confine the protection scope of the present application. Although the present application has been explained in detail by preferred embodiments, a person of ordinary skill in the art should understand that the technical solution of the present application can be modified or equivalently replaced without departing from the essence and the scope of the technical solution of the present application.


Claims

1. A method for preparing a densely-arranged solar cell string, comprising the following steps:

(1) preparing a solar cell, wherein main grids and fine grids of the solar cell are perpendicular to each other; the main grids are segmented electrodes, and welding points for electrical connection between cells are arranged at ends of the segmented main grids; the positions of the main grid welding points on the back surface and the positions of the main grid welding points on the front surface are symmetrical about a center; and, a cell cutting region is further provided on the solar cell, and the cell cutting region is perpendicular to the main grids;

(2) printing a strip-shaped hot melt adhesive: printing the strip-shaped hot melt adhesive at the welding points of the segmented main grids in a direction perpendicular to the main grids;

(3) cutting the cell: cutting, along the cell cutting region, the solar cell into a plurality of small cells;

(4) coating a conductive adhesive or solder paste: coating the conductive adhesive or solder paste at the main grid welding points on the front surfaces of the small cells;

(5) adhering the small cells: superposing main grid welding points on a back surface of one small cell onto main grid welding points on a front surface of another small cell, and heating so that the two small cells are electrically connected through the conductive adhesive or solder paste; and, melting the hot melt adhesive while heating, and solidifying the hot melt adhesive after cooling, so that the two small cells are closely adhered together and the welding points on the two small cells form firm ohmic contact; and

(6) repeating the step (5) for the plurality of small cells so that the plurality of small cells are successively connected to form a solar cell string.


 
2. The preparation method according to claim 1, wherein there are 3 to 15 main grids each having a width of 100 to 1200 µm.
 
3. The preparation method according to claim 1 or 2, wherein the cell cutting region has a width of 1 to 2 mm; the hot melt adhesive has a width of 1 to 3 mm, and the welding points are exposed from the hot melt adhesive; and, the hot melt adhesive needs to be dried at a temperature of below 150°C after printed.
 
4. The preparation method according to claim 1 or 2, wherein, in the step (3), the cutting is laser cutting.
 
5. The preparation method according to claim 1 or 2, wherein, in the step (5), the heating is resistance wire heating or infrared heating.
 
6. A densely-arranged solar cell string, comprising solar cell units, wherein fine grids, main grids and main grid welding points are provided on front and back surfaces of the solar cell units, and the main grid welding points are arranged at ends of the main grids; a hot melt adhesive is coated on the front surfaces of the solar cell units along a direction of the fine grids, the hot melt adhesive is disconnected in a region of the main grid welding points, and a conductive adhesive or solder paste is coated at the main grid welding points; the back surface of one solar cell unit is superposed onto the front surface of another solar cell unit along a long-side direction, and the width of an superposed region of the two solar cell units is the width of the main grid wielding points; and, the main welding points on the back surface of one solar cell unit come into ohmic contact with the main grid welding points on the front surface on another solar cell unit through the conductive adhesive or solder paste, so that the two solar cell units are bonded together through the hot melt adhesive.
 
7. The solar cell string according to claim 6, wherein electrodes on the back and front surfaces of the solar cell units are H-type electrodes, and the main grids and the fine grids are perpendicular to each other.
 
8. The solar cell string according to claim 6 or 7, wherein the hot melt adhesive has a width of 1 to 3 mm.
 
9. A densely-arranged solar cell module, comprising a front layer material, a packaging material, a solar cell string, the packaging material and a back layer material which are successively arranged from the top down, the solar cell string being the solar cell string according to any one of claims 6 to 8.
 
10. A solar cell system, comprising at least one solar cell module connected in series, wherein the solar cell module is the solar cell module according to claim 9.
 




Drawing



















REFERENCES CITED IN THE DESCRIPTION



This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description