An interconnection method for a back contact cell assembly without a main grid

Abstract

The present application relates to the technical field of battery production, in particular to a kind of interconnection method of back contact battery module without main grid, comprising: printing insulating glue on positive fine grid line or negative fine grid line;The battery piece printed with insulating glue is subjected to drying treatment;Print conductive glue on the fine grid line without printing insulating glue, the conductive glue is composed of soldering part and conductive connecting part;Lay solder strip on the battery piece, and press the solder strip on the conductive glue;Drying conductive glue for preliminary curing, and pre-fix the solder strip on the battery piece;Then, laminating and welding treatment is carried out, to realize the alloying connection of solder strip and fine grid line.The present application uses conductive glue composed of soldering part and conductive connecting part, cooperates with insulating glue to be used together, reduces the problem that traditional tin paste / insulating glue / curing glue combination needs multiple baking of battery piece, simplifies process, reduces the warping condition of battery piece, guarantees the yield of battery piece, guarantees the quality of battery piece.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery production, in particular to a method for interconnecting a back contact battery module without main grid. BACKGROUND

[0002] In solar applications, photovoltaic power generation is an important application method, which is gradually widely used due to its advantages of no noise, maintenance-free, no emission, etc. Crystalline silicon solar cells dominate the photovoltaic power generation field, which is mainly due to the rich reserves of silicon material in the earth's crust, relatively mature photovoltaic power generation technology and lower cost.

[0003] At present, the main method for interconnecting the battery module without main grid back contact battery in the photovoltaic industry is to use the laminated welding method of battery pieces, which can be referred to as the prior art. Figures 1-3 That is, tin paste, insulating glue, and curing glue are printed on the battery piece in turn, and then the solder strip is laid on the battery piece to be fixed, and the welding of the solder strip and the fine grid is completed in the laminating process. The function of the insulating glue is to avoid short circuit caused by direct contact of the solder strip with the fine grid line with opposite polarity; the function of the tin paste is to increase the height of the welding part, thereby assisting welding; the function of the curing glue is to fix the solder strip to avoid its deviation during lamination. The specific steps are as follows: near the position (welding part) where the fine grid of the battery piece contacts the solder strip, insulating glue is printed on the fine grid line with opposite polarity, and drying treatment is performed. Then, tin paste is printed on the welding part, and drying is performed again. Finally, curing glue is printed at the position where the solder strip contacts the battery piece with a certain gap, the solder strip is laid on the battery piece, the battery string is heated and dried, and then glass, film, battery string, film, and back plate are laminated in turn, and then sent into the laminator for lamination, thereby completing the interconnection welding of the back contact module without main grid.

[0004] The disadvantage of the above interconnection method is low yield and poor reliability. Since the battery piece needs to be printed and dried three times, the process is complex, and the battery piece undergoes three cold and hot cycles, which causes the battery piece to warp, affects the mechanical strength of the battery piece, and thus leads to a decrease in the yield of the battery module. In addition, since the battery piece no longer has a main grid, the solder strip can only collect current through the fine grid, and the width of the fine grid is small. The solder strip welded thereon frequently applies shear stress to the fine grid due to thermal expansion and contraction during outdoor cold and hot cycles, and the fine grid is prone to breakage under the action of this stress, causing the current of the entire fine grid to be unable to be collected, which seriously affects the power generation performance of the battery module and leads to a lack of reliability of the battery module. Based on this, a method for interconnecting a back contact battery module without main grid is proposed. SUMMARY

[0005] In view of the shortcomings of the prior art, the present application provides a method for interconnecting a back contact battery module without main grid, which uses conductive glue composed of a soldering part and a conductive connecting part, and cooperates with insulating glue to simplify the process and ensure the quality of the battery piece.

[0006] To achieve the above object, the present application provides the following technical scheme: a method for interconnecting a back contact cell assembly without main grid, comprising the following steps,

[0007] (1) printing insulating glue on the positive or negative fine grid line, the insulating glue being arranged in the same line;

[0008] (2) drying the cell piece printed with the insulating glue;

[0009] (3) printing conductive glue on the fine grid line without printing the insulating glue, the conductive glue being composed of a soldering part and a conductive connecting part, the conductive glue also being arranged in the same line as the insulating glue;

[0010] (4) laying solder strips on the cell piece, and pressing the solder strips on the conductive glue;

[0011] (5) drying the conductive glue for preliminary solidification, and pre-fixing the solder strips on the cell piece;

[0012] (6) then performing lamination welding treatment to realize alloying connection of the solder strips and the fine grid line.

[0013] Preferably, in step (1), the height of the insulating glue is 10-50 μm, and the resistivity thereof is ≥ 1×10 14 Ω·cm.

[0014] Preferably, in step (3), the conductive glue is silver powder conductive glue, carbon powder conductive glue or aluminum powder conductive glue; the height thereof is 25-60 μm, the resistivity thereof is ≤ 1×10 -5 Ω·cm, the tensile strength thereof is ≥ 10 MPa, and the peeling strength thereof is ≥ 0.5 N / cm.

[0015] Preferably, in step (3), the soldering part is a solid circle, and the diameter thereof is 0.5-0.8 times the width of the solder strip.

[0016] Preferably, in step (3), the conductive connecting part is a hollow rectangle, the length of the hollow rectangle is 1.2-1.8 times the width of the solder strip, the width of the hollow rectangle is 0.5-2 times the distance between adjacent fine grid lines, and the edge end width is 25-100 μm.

[0017] Preferably, in step (3), the conductive connecting part is a hollow triangle, the side length of the hollow triangle is 1.2-1.8 times the width of the solder strip, the height of the hollow triangle is 0.5-2 times the distance between adjacent fine grid lines, and the edge end width is 25-100 μm.

[0018] Preferably, in step (3), the conductive connecting part is a hollow circle, the diameter of the hollow circle is 1.2-1.8 times the width of the solder strip, and the edge end width is 25-100 μm.

[0019] Preferably, in step (6), the lamination welding temperature is 130-150 DEG C, and the lamination welding time is 5-15 min.

[0020] The application provides a method for interconnecting a back contact cell assembly without a main grid, and has the following beneficial effects compared with the prior art:

[0021] The conductive adhesive of the application is composed of a soldering part and a conductive connecting part, and is used together with insulating adhesive, thereby reducing the problem of multiple baking of the battery piece required by the traditional combination of tin paste / insulating adhesive / curing adhesive, simplifying the process, reducing the warping of the battery piece, and ensuring the yield of the battery piece.

[0022] The application constructs a connected conductive connecting part around the soldering part, so that even if the fine grid line is broken at the position of the soldering part, the current can be collected through the conductive connecting part, thereby ensuring the quality of the battery piece. BRIEF DESCRIPTION OF DRAWINGS

[0023] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and serve to explain the application without imposing undue limitation thereon. In the drawings:

[0024] Figure 1 It is a distribution diagram of the insulating adhesive, curing adhesive and tin paste in the prior art;

[0025] Figure 2 It is a schematic diagram of battery piece string welding in the prior art;

[0026] Figure 3 It is a flowchart of interconnection of the back contact cell assembly without a main grid in the prior art;

[0027] Figure 4 It is a distribution diagram of the conductive adhesive and insulating adhesive in the application;

[0028] Figure 5 It is a schematic diagram of battery piece string welding in the application;

[0029] Figure 6 It is a schematic diagram of the structure of the soldering part and the hollow rectangular conductive connecting part in the application;

[0030] Figure 7 It is a schematic diagram of the structure of the soldering part and the hollow triangular conductive connecting part in the application;

[0031] Figure 8 It is a schematic diagram of the structure of the soldering part and the hollow circular ring conductive connecting part in the application;

[0032] Figure 9 It is a flowchart of interconnection of the back contact cell assembly without a main grid in the application. DETAILED DESCRIPTION

[0033] The following examples are used to illustrate the embodiments of the present application, by which the technical means applied by the present application to solve the technical problems and achieve the technical effects can be fully understood and implemented.

[0034] Example 1

[0035] A method for interconnecting a back contact cell assembly without a main grid, comprising the following steps:

[0036] (1) Printing insulating glue on the positive fine grid lines, the height of the insulating glue being 10 μm, the resistivity thereof being ≥ 1×10 14 Ω·cm, and the insulating glue being arranged in the same straight line.

[0037] (2) Drying the cell piece printed with the insulating glue.

[0038] (3) Printing carbon powder conductive glue on the fine grid lines (negative fine grid lines) not printed with the insulating glue, the height of the conductive glue being 25 μm, the resistivity thereof being ≤ 1×10 -5 Ω·cm, the tensile strength thereof being ≥ 10 MPa, the peeling strength thereof being ≥ 0.5 N / cm, the conductive glue being composed of a soldering part and a conductive connecting part, and the conductive glue also being arranged in the same straight line as the insulating glue.

[0039] The soldering part is a solid circle, the diameter of which is 0.8 times the width of the soldering tape. The conductive connecting part is a hollow rectangle, the length of the hollow rectangle being 1.2 times the width of the soldering tape, the width of the hollow rectangle being 2 times the distance between adjacent fine grid lines, and the edge end width being 25 μm.

[0040] (4) Laying the soldering tape on the cell piece, and pressing the soldering tape on the conductive glue.

[0041] (5) Drying the conductive glue to preliminarily solidify, and pre-fixing the soldering tape on the cell piece.

[0042] (6) Subsequently, performing lamination welding treatment, laminating for 5 min at 150 ℃, and realizing alloying connection of the soldering tape and the fine grid lines.

[0043] Example 2

[0044] A method for interconnecting a back contact cell assembly without a main grid, comprising the following steps:

[0045] (1) Printing insulating glue on the negative fine grid lines, the height of the insulating glue being 50 μm, the resistivity thereof being ≥ 1×10 14 Ω·cm, and the insulating glue being arranged in the same straight line.

[0046] (2) Drying the cell piece printed with the insulating glue.

[0047] (3) printing aluminum powder conductive adhesive on the fine grid line (positive fine grid line) without printing insulating adhesive, the height of which is 60 μm, and the resistivity is ≤ 1×10 -5 Ω·cm, the tensile strength is ≥ 10 MPa, and the peel strength is ≥ 0.5 N / cm, the conductive adhesive is composed of a soldering assisting part and a conductive connecting part, and the conductive adhesive is also arranged in the same straight line with the insulating adhesive;

[0048] The soldering assisting part is a solid circle, and the diameter thereof is 0.5 times the width of the solder strip. The conductive connecting part is a hollow rectangle, the length of the hollow rectangle is 1.8 times the width of the solder strip, the width of the hollow rectangle is 0.5 times the interval between adjacent fine grid lines, and the edge end width is 100 μm.

[0049] (4) laying the solder strip on the battery sheet and pressing the solder strip on the conductive adhesive.

[0050] (5) drying the conductive adhesive for preliminary curing and pre-fixing the solder strip on the battery sheet.

[0051] (6) then performing lamination welding treatment at 130 ℃ for 15 min to realize alloying connection of the solder strip and the fine grid line.

[0052] Example 3

[0053] A kind of interconnection method of main grid-free back contact battery module, comprising the following steps:

[0054] (1) printing insulating adhesive on the positive fine grid line, the height of the insulating adhesive is 30 μm, the resistivity is ≥ 1×10 14 Ω·cm, and the insulating adhesive is arranged in the same straight line.

[0055] (2) drying the battery sheet with the printed insulating adhesive.

[0056] (3) printing silver powder conductive adhesive on the fine grid line (negative fine grid line) without printing insulating adhesive, the height of which is 42 μm, and the resistivity is ≤ 1×10 -5 Ω·cm, the tensile strength is ≥ 10 MPa, and the peel strength is ≥ 0.5 N / cm, the conductive adhesive is composed of a soldering assisting part and a conductive connecting part, and the conductive adhesive is also arranged in the same straight line with the insulating adhesive;

[0057] The soldering assisting part is a solid circle, and the diameter thereof is 0.6 times the width of the solder strip. The conductive connecting part is a hollow rectangle, the length of the hollow rectangle is 1.5 times the width of the solder strip, the width of the hollow rectangle is 1.2 times the interval between adjacent fine grid lines, and the edge end width is 50 μm.

[0058] (4) laying the solder strip on the battery sheet and pressing the solder strip on the conductive adhesive.

[0059] (5) drying the conductive adhesive for preliminary curing and pre-fixing the solder strip on the battery sheet.

[0060] (6) Then, a lamination welding treatment is performed, and lamination is performed at 140°C for 10 min to achieve alloying connection of the solder tape and the fine grid lines.

[0061] Example 4

[0062] A method for interconnecting a back contact cell assembly without a main grid is substantially the same as that of Example 3, except that:

[0063] In step (3), the conductive connecting part is a hollow triangle, the side length of the hollow triangle is 1.5 times the width of the solder tape, the height is 1.2 times the pitch between adjacent fine grid lines, and the edge end width is 50 μm.

[0064] Example 5

[0065] A method for interconnecting a back contact cell assembly without a main grid is substantially the same as that of Example 4, except that the side length of the hollow triangle is 1.2 times the width of the solder tape, the height is 0.5 times the pitch between adjacent fine grid lines, and the edge end width is 25 μm.

[0066] Example 6

[0067] A method for interconnecting a back contact cell assembly without a main grid is substantially the same as that of Example 4, except that the side length of the hollow triangle is 1.8 times the width of the solder tape, the height is 1.9 times the pitch between adjacent fine grid lines, and the edge end width is 100 μm.

[0068] Example 7

[0069] A method for interconnecting a back contact cell assembly without a main grid is substantially the same as that of Example 3, except that:

[0070] In step (3), the conductive connecting part is a hollow circle, the diameter of the hollow circle is 1.5 times the width of the solder tape, and the edge end width is 50 μm.

[0071] Example 8

[0072] A method for interconnecting a back contact cell assembly without a main grid is substantially the same as that of Example 7, except that the diameter of the hollow circle is 1.2 times the width of the solder tape, and the edge end width is 25 μm.

[0073] Example 9

[0074] A method for interconnecting a back contact cell assembly without a main grid is substantially the same as that of Example 7, except that the diameter of the hollow circle is 1.8 times the width of the solder tape, and the edge end width is 100 μm.

[0075] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and adaptions can be effected without departing from the spirit and scope of the present application, which is not limited to the exact construction and arrangement described. It is intended, therefore, to cover all modifications and adaptions that fall within the scope of the claims and their equivalents.

Claims

1. A method of interconnecting a back contact cell assembly without a main grid, characterized in that, The method comprises the following steps: (1) printing insulating glue on the positive or negative fine grid lines, the insulating glue being arranged in the same line; (2) drying the battery piece printed with the insulating glue; (3) printing conductive glue on the fine grid line without printing the insulating glue, the conductive glue being composed of a soldering assisting part and a conductive connecting part, the conductive glue also being arranged in the same line with the insulating glue; (4) laying the soldering ribbon on the battery piece, and pressing the soldering ribbon on the conductive glue; (5) drying the conductive glue to preliminarily solidify, and pre-fixing the soldering ribbon on the battery piece; (6) then, performing lamination welding treatment to realize alloying connection between the soldering ribbon and the fine grid line. The soldering assisting part is a solid circle, and the conductive connecting part is a hollow rectangle, a hollow triangle or a hollow circle surrounding the soldering assisting part.

2. The interconnecting method of a back contact cell assembly without a main grid according to claim 1, wherein, In step (1), the height of the insulating glue is 10-50 μm, and the resistivity is ≥ 1 x 10 14 Ω·cm.

3. The interconnecting method of a no-lead back contact cell assembly according to claim 1, wherein, In step (3), the conductive adhesive is silver powder conductive adhesive, carbon powder conductive adhesive or aluminum powder conductive adhesive; the height is 25-60 μm, the resistivity is ≤ 1 x 10 -5 Ω·cm, the tensile strength is ≥ 10 MPa, and the peeling strength is ≥ 0.5 N / cm.

4. The interconnecting method of a no- main grid back contact cell assembly according to claim 1, wherein, In step (3), the soldering assisting part is a solid circle, and the diameter of the solid circle is 0.5-0.8 times the width of the soldering ribbon.

5. The interconnecting method of a no- main grid back contact cell assembly according to claim 1, wherein, In step (3), the conductive connecting part is a hollow rectangle, the length of the hollow rectangle is 1.2-1.8 times the width of the soldering ribbon, the width of the hollow rectangle is 0.5-2 times the distance between adjacent fine grid lines, and the edge end width is 25-100 μm.

6. The interconnecting method of a no- main grid back contact cell assembly according to claim 1, wherein, In step (3), the conductive connecting part is a hollow triangle, the side length of the hollow triangle is 1.2-1.8 times the width of the soldering ribbon, the height of the hollow triangle is 0.5-2 times the distance between adjacent fine grid lines, and the edge end width is 25-100 μm.

7. The interconnecting method of a no- main grid back contact cell assembly according to claim 1, wherein, In step (3), the conductive connecting part is a hollow circle, the diameter of the hollow circle is 1.2-1.8 times the width of the soldering ribbon, and the edge end width is 25-100 μm.

8. The interconnecting method of a no- main grid back contact cell assembly according to claim 1, wherein, In step (6), the lamination welding temperature is 130-150 ℃, and the lamination welding time is 5-15 min.

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