Imbricated tile assembly and preparation method thereof

Abstract

The invention discloses an imbricated assembly which comprises a plurality of small battery pieces formed by cutting along a battery piece cutting line, and the small battery pieces are alternately arranged according to the polarity of positive and negative electrodes and are mutually overlapped into a string; a plurality of main grid lines are respectively arranged on the front surfaces and the back surfaces of the small battery pieces, and a plurality of main grid line welding spots are arranged on the main grid lines; an insulating tape avoiding the position of the electrode is arranged at the position where the front surface of the small battery piece is overlapped with the back surface of the small battery piece; at least one main grid line welding spot on each main grid line is positioned in the insulating tape but is not covered by the insulating tape; a metal conductor is also arranged between the two layers of insulating tapes; low-temperature solder paste is coated in the insulating tape area along the direction of the cutting line; according to the invention, the insulating tape is printed on the surface of the battery piece in a silk-screen printing manner, the connection of the positive electrode and the negative electrode of the battery piece and the transmission of main grid line current are not influenced while the insulating isolation is ensured, and the small battery pieces are connected by adopting low-temperature solder paste, so that the operation difficulty and the workload during lamination are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic cell assemblies, and in particular to a shingled assembly and a preparation method thereof. Background Art

[0002] The shingled module achieves close arrangement of the cells by cutting the cells into small strips and stacking them together through materials such as conductive glue or adhesive. However, this close arrangement also brings challenges to the insulation between the cells. In order to ensure the insulation between the cells, it is necessary to add insulating materials between the cells or adopt special insulation designs.

[0003] In the prior art, the overlapping parts of the cells in the shingled module can be connected by conductive glue or adhesive, but these connected parts need to ensure sufficient insulation spacing. Insulating spacers are added between the cells. These spacers are usually made of transparent polymer materials. They can effectively block the current and ensure the insulation between the cells. However, in the shingled module, the conductive glue or adhesive used in the overlapping parts of the cells not only has the risk of overflowing and causing a short circuit, but also the large amount of silver in the slurry makes the module cost high, which is not conducive to mass production.

[0004] In addition, the commonly used base materials of conductive adhesives include epoxy resins, polyurethanes, phenolic resins, etc. These materials form the molecular skeleton structure of the conductive adhesive after curing, providing mechanical and bonding performance guarantees. The main function of conductive adhesives is to provide conductive connections, not insulation. From a design perspective, conductive adhesives do not have significant insulation properties.

[0005] In addition, the shingled cells themselves are small in size and closely arranged, and the gaps between the cells are usually at the millimeter level or even smaller, which means that the operating space for the hands and tools of the construction workers is very limited when performing insulation operations. Due to the small operating space, it is difficult to ensure uniform force and accurate pasting for some processes that require pasting or fixing of insulating materials, such as using insulating glue or tape. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a shingled assembly and a preparation method thereof, which can solve the problem that the conductive adhesive cannot ensure insulation at the overlapping parts of the battery cells, and the problem of difficult stacking operations, thereby reducing the difficulty and workload of stacking operations.

[0007] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows.

[0008] A shingled assembly comprises a plurality of battery chips formed by cutting along a battery chip cutting line, wherein the battery chips are arranged alternately according to positive and negative polarities and overlap each other to form a string, and the back side of the battery chip of the previous battery chip overlaps the front side of the battery chip of the next battery chip; a plurality of main grid lines are respectively arranged on the front side and the back side of the battery chip, and a plurality of main grid line welding points are arranged on the main grid lines; an insulating belt avoiding the electrode position is arranged at the position where the front side and the back side of the battery chip overlap; at least one main grid line welding point on each main grid line is located in the insulating belt but is not covered by the insulating belt; a metal conductor consistent with the cutting line direction is also arranged between the two layers of insulating belt; and low-temperature solder paste is coated on the insulating belt area along the cutting line direction.

[0009] In the above-mentioned shingled assembly, the insulating belt is in the shape of a narrow strip, and the corners of the insulating belt are designed with bevel edges or rounded corners.

[0010] In the above-mentioned shingled assembly, the width of the low-temperature solder paste is smaller than the width of the insulating tape.

[0011] In the above-mentioned shingled assembly, the low-temperature solder paste is intermittently or continuously coated on the insulating area of ​​the insulating tape, and the position where the main grid wire solder point contacts the metal conductor is coated with the low-temperature solder paste.

[0012] In the above-mentioned shingled assembly, the metal conductor is copper wire, silver-clad copper wire, welding strip, or silver foil.

[0013] A method for preparing a shingled assembly, the method being implemented based on any one of the shingled assemblies described above, comprising the following steps:

[0014] The first step is to pre-treat the silicon wafer and print electrodes, and then form the battery cell by cutting;

[0015] The second step is to print the insulating tape on the battery cell by screen printing. During the printing process, the electrode position must be avoided and at least one main grid wire welding point on the front and back main grid wires of the battery cell must be located in the insulating tape area.

[0016] The third step is to cut the battery cell into several small battery cells along the cutting line;

[0017] The fourth step is to alternately arrange the battery chips according to the positive and negative polarities and overlap each other to form a string. During the arrangement process, the back of the battery chip of the previous battery chip is overlapped with the front of the battery chip of the next battery chip, and a metal conductor is installed at the overlapping part, and a low-temperature solder paste is applied on the insulating tape between the front and back of the battery chip to connect the front of the battery chip with the back of another battery chip;

[0018] When applying low-temperature solder paste, it is necessary to ensure that low-temperature solder paste is also applied between the metal conductor and the main grid line solder joint.

[0019] Due to the adoption of the above technical scheme, the technical progress achieved by the present invention is as follows.

[0020] The present invention provides a shingled assembly and a preparation method thereof, wherein an insulating tape is printed on the surface of a battery cell by screen printing, and avoids the electrode position and the main grid wire welding point position, so as to ensure insulation isolation while not affecting the positive and negative electrode connection of the battery cell and the transmission of the main grid wire current, and also reduce internal energy loss by setting a metal conductor as an efficient current transmission channel inside the battery cell.

[0021] The present invention uses low-temperature solder paste to connect battery chips. Since the low-temperature solder paste has a low melting point, the risk of thermal damage during the welding process is reduced. At the same time, the low-temperature solder paste can effectively diffuse and adhere to the welding surface, ensuring a good welding connection and reducing the operating difficulty and workload during stacking. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the specific structure of the present invention;

[0023] Figure 2 This is an enlarged structural diagram of the connection between the front and back sides of the battery chip of the present invention;

[0024] Figure 3 This is a schematic diagram of the structure of the front side of the battery chip of the present invention;

[0025] Figure 4 It is a schematic structural diagram of the back side of the battery chip described in the present invention.

[0026] Among them: 1. Front of the battery chip, 2. Back of the battery chip, 3. Main grid line, 4. Main grid line solder joint, 5. Insulation tape, 6. Metal conductor, 7. Low-temperature solder paste, 8. Cutting line. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] A shingled assembly, such as Figures 1 to 4 As shown, it includes a plurality of battery chips formed by cutting along a battery chip cutting line 8. The battery chips are arranged alternately according to positive and negative polarities and overlap each other to form a string. The back side 2 of the previous battery chip overlaps the front side 1 of the next battery chip.

[0029] A plurality of busbars 3 are respectively arranged on the front side 1 of the battery chip and the back side 2 of the battery chip, and a plurality of busbar welding points 4 are arranged on the busbars 3 .

[0030] An insulating tape 5 avoiding the electrode position is arranged at the overlap position of the front side 1 and the back side 2 of the battery chip. The insulating tape 5 is a narrow strip, and the corners of the insulating tape 5 are designed with bevel edges or rounded corners. After lamination, the width of the insulating tape is 1mm to 2mm.

[0031] At least one busbar welding point 4 on each busbar 3 is located within the insulating tape 5 but not covered by the insulating tape, ensuring the connection between the front busbar and the back busbar, facilitating the transmission of current between the positive and negative electrodes.

[0032] A metal conductor 6 is also provided between the two layers of insulating tapes 5 in the same direction as the cutting line 8. The metal conductor 6 is a copper wire, a silver-clad copper wire, a welding tape, or a silver foil.

[0033] The metal conductor 6 may be a thin and long wire with a wire diameter of 0.08-0.15 mm, which may be selected according to the current size or resistance requirements.

[0034] The metal conductor may also be a thin film with a smooth and uniform surface, and the thickness of the film is 0.05-0.20 mm.

[0035] The insulating tape region along the cutting line 8 is intermittently or continuously coated with low-temperature solder paste 7 , and the width of the low-temperature solder paste 7 is smaller than the width of the insulating tape 5 .

[0036] Low-temperature solder paste has a lower melting point (usually around 138°C) and can complete the soldering process at a relatively low temperature (120°C-160°C), reducing the risk of thermal damage.

[0037] Low-temperature solder paste itself has good wettability and can effectively spread and adhere to the soldering surface to ensure good soldering connections. Due to the low soldering temperature, it can also reduce energy costs in the production process.

[0038] When applying the low-temperature solder paste 7, it is necessary to ensure that the low-temperature solder paste 7 is also coated between the metal conductor 6 and the main grid line solder point 4. The main grid line solder point 4 and the metal conductor 6 are connected by the low-temperature solder paste, and the main grid lines on each battery cell are connected by the metal conductor 6. It can serve as an efficient current transmission channel inside the battery cell. Since the metal conductor has excellent conductivity and low resistance, it can reduce internal energy loss.

[0039] The present invention also provides a method for preparing a shingled assembly, which is implemented based on the above-mentioned shingled assembly and includes the following steps:

[0040] The first step is to pre-treat the silicon wafer and print electrodes, and then form the battery cell by cutting;

[0041] The second step is to print the insulating tape 5 on the battery cell by screen printing, and ensure that at least one main grid wire welding point 4 on the front and back main grid wires of the battery cell is located in the insulating tape area;

[0042] Step 3: Cut the battery cell into several small battery cells along the cutting line 8;

[0043] Step 4: Alternately arrange the battery chips according to the positive and negative polarities and overlap each other to form a string. During the arrangement process, the back side 2 of the battery chip of the previous battery chip overlaps the front side 1 of the battery chip of the next battery chip, and at the same time, a metal conductor 6 is installed at the overlapping part, and a low-temperature solder paste 7 is coated on the insulating tape 5 between the front side and the back side of the battery chip to connect the front side of the battery chip with the back side of another battery chip;

[0044] When applying the low-temperature solder paste 7 , it is necessary to ensure that the low-temperature solder paste 7 is also applied between the metal conductor 6 and the main grid line solder joint 4 .

[0045] The present invention provides a shingled assembly and a preparation method thereof, wherein an insulating tape is printed on the surface of a battery cell by screen printing, and avoids the electrode position and the main grid wire welding point position, so as to ensure insulation isolation while not affecting the positive and negative electrode connection of the battery cell and the transmission of the main grid wire current, and also reduce internal energy loss by setting a metal conductor as an efficient current transmission channel inside the battery cell.

[0046] The present invention uses low-temperature solder paste to connect battery chips. Since the low-temperature solder paste has a low melting point, the risk of thermal damage during the welding process is reduced. At the same time, the low-temperature solder paste can effectively diffuse and adhere to the welding surface, ensuring a good welding connection and reducing the operating difficulty and workload during stacking.

Claims

1. A shingled assembly, characterized in that: The invention comprises a plurality of battery chips formed by cutting along a battery chip cutting line (8), wherein the battery chips are arranged alternately according to positive and negative polarities and overlap each other to form a string, and the back side (2) of the battery chip of the previous battery chip is overlapped with the front side (1) of the battery chip of the next battery chip; a plurality of main grid lines (3) are respectively arranged on the front side (1) and the back side (2) of the battery chip, and a plurality of main grid line welding points (4) are arranged on the main grid lines (3); an insulating belt (5) avoiding the electrode position is arranged at the position where the front side (1) and the back side (2) of the battery chip overlap; at least one main grid line welding point (4) on each main grid line (3) is located in the insulating belt (5) but is not covered by the insulating belt; a metal conductor (6) is also arranged between the two layers of insulating belt (5) in the same direction as the cutting line (8); and a low-temperature solder paste (7) is coated in the insulating belt area along the cutting line (8).

2. The shingled assembly according to claim 1, characterized in that: The insulating belt (5) is in the shape of a narrow strip, and the corners of the insulating belt (5) are designed with beveled edges or rounded corners.

3. The shingled assembly according to claim 1, characterized in that: The width of the low-temperature solder paste (7) is smaller than the width of the insulating tape (5).

4. The shingled assembly according to claim 1, characterized in that: The low-temperature solder paste (7) is intermittently or continuously coated on the insulating area of ​​the insulating tape, and the position where the main grid wire solder point (4) contacts the metal conductor (6) is coated with the low-temperature solder paste.

5. The shingled assembly according to claim 1, characterized in that: The metal conductor (6) is copper wire, silver-clad copper wire, welding strip, or silver foil.

6. A method for preparing a shingled assembly, characterized in that: The method is implemented based on the shingled assembly according to any one of claims 1 to 5, and comprises the following steps: The first step is to pre-treat the silicon wafer and print electrodes, and then form the battery cell by cutting; The second step is to print the insulating tape (5) on the battery cell by screen printing. During the printing process, the electrode position must be avoided and at least one main grid wire welding point (4) on the front and back main grid wires of the battery cell must be located in the insulating tape area; The third step is to cut the battery sheet into a plurality of small battery sheets along the cutting line (8); The fourth step is to alternately arrange the battery chips according to the positive and negative polarities and overlap each other to form a string. During the arrangement process, the back side (2) of the battery chip of the previous battery chip is overlapped with the front side (1) of the battery chip of the next battery chip, and at the same time, a metal conductor (6) is installed at the overlapping part, and a low-temperature solder paste (7) is coated on the insulating tape (5) between the front side and the back side of the battery chip to connect the front side of the battery chip with the back side of another battery chip; When applying the low-temperature solder paste (7), it is necessary to ensure that the low-temperature solder paste (7) is also applied between the metal conductor (6) and the main grid wire soldering point (4).

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