Welding method for main-grid-free battery

Abstract

The invention relates to the technical field of battery welding, in particular to a main-grid-free battery welding method, which comprises the following steps of: placing a main-grid-free battery on a conventional bottom plate, coating solder paste or conductive adhesive on the front surface of the main-grid-free battery, and enabling the solder paste or conductive adhesive to be vertical to fine grid lines on the front surface of the battery; turning over the main-grid-free battery and placing the main-grid-free battery on the hollowed-out bottom plate, enabling the back surface of the main-grid-free battery to face upwards, coating solder paste or conductive adhesive on the back surface of the main-grid-free battery, and enabling the solder paste or conductive adhesive to be vertical to the thin grid lines on the back surface of the battery; and arranging wires at the solder paste or conductive adhesive coated and printed on the main-grid-free battery, and sequentially arranging the wires for welding. The solder paste or the conductive adhesive is vertically coated and printed on the plurality of groups of fine grid lines on the surface of the battery and is heated and cured, so that the strip-shaped bulges are in contact with each group of fine grid lines, and the solder strip can be fully connected with the plurality of groups of fine grid lines through auxiliary conduction of the solder paste or the conductive adhesive during subsequent welding of the solder strip; the problem that part of fine grid lines cannot be firmly contacted with the welding strip during traditional welding is solved, and the quality of the main-grid-free battery piece is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of battery welding, and in particular to a main grid-free battery welding method. Background Art

[0002] The power generation substrate of silicon solar cells is silicon wafers. Conventional solar cells are printed with many fine grid lines to collect the current generated by the silicon wafers after being exposed to light, and also printed with multiple main grid lines to collect the current on the fine grid lines. Under the goal of low-cost, high-power solar cells, busbar-free solar cell technology came into being. Busbar-free solar cells are based on conventional solar cells, with the main grid lines removed and the fine grid lines retained. At present, the production solutions for busbar-free solar cell strings are divided into three solutions: Smart Wire, glue dispensing, and welding glue dispensing.

[0003] As for the dispensing solution, it includes four steps: dispensing, wiring, curing, and lamination alloying. The general process is as follows. Figure 1 and attached Figure 2 As shown. The advantages of this solution are simple equipment and strong stability. The disadvantages are that there is a shadow under the soldering tape during EL detection, which affects the detection accuracy; and the soldering tape and the battery cell are not well fitted, which leads to poor tensile strength. In addition, the soldering tape is difficult to contact all the fine grid lines, which affects the current collection and thus affects the quality of the busbar-free battery cell. Based on this, a busbar-free battery welding method is proposed. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a busbar-free battery welding method, which solves the problem that some thin grid lines cannot be firmly contacted with the welding strip during traditional welding, and ensures the quality of the busbar-free battery sheet.

[0005] To achieve the above object, the present invention provides the following technical solution: a busbar-free battery welding method, comprising the following steps:

[0006] (1) Place the busbar-free battery on a conventional base plate, and apply solder paste or conductive glue to the front of the busbar-free battery through a screen printing plate so that it is perpendicular to the fine grid lines on the front of the battery;

[0007] (2) Flip the busbar-free battery and place it on the hollow bottom plate with its back facing upwards, and apply solder paste or conductive glue on the back of the busbar-free battery through a printing screen so that it is perpendicular to the fine grid lines on the back of the battery;

[0008] (3) Lay out wires in the areas where solder paste or conductive glue is printed without main grid cells, arrange them in sequence, and perform welding using a string welding machine.

[0009] Preferably, in steps (1) and (2), the printed solder paste or conductive adhesive is distributed in strips on the surface of the busbar-free battery.

[0010] Preferably, in steps (1) and (2), after the solder paste or conductive adhesive is printed on the surface of the busbar-free battery, a heating and curing treatment is performed to allow the solder paste or conductive adhesive to form a cured connection with the fine grid lines.

[0011] Preferably, in step (2), a plurality of groups of hollow grooves are provided on the surface of the hollow bottom plate, and the number of the hollow grooves is greater than the number of strip-shaped protrusions formed by the solder paste or the conductive adhesive.

[0012] Preferably, the length and width of the hollow groove are greater than the length and width of the strip-shaped protrusion formed by the solder paste or the conductive glue.

[0013] The present invention provides a main grid-free battery welding method, which has the following beneficial effects compared with the prior art:

[0014] The present invention vertically prints solder paste or conductive glue on several groups of fine grid lines on the surface of the battery, and heats and cures them, so that the formed strip-shaped protrusions can contact each group of fine grid lines. During the subsequent soldering of the solder strip, the auxiliary conduction of the solder paste or conductive glue can ensure that the solder strip is fully connected to the several groups of fine grid lines, thereby solving the problem that some fine grid lines cannot be firmly contacted with the solder strip during traditional welding, and ensuring the quality of the main grid-free battery cell.

[0015] When printing on the back of the battery, the present invention adopts a hollow bottom plate to replace the traditional conventional bottom plate. After the printed solder paste or conductive glue is heated and cured, its height forms a height difference with the front of the battery, and the metal hardness characteristics after curing are enhanced. If a conventional seamless bottom plate is used, the pressure generated when printing on the back of the battery may easily cause hidden cracks or splits in the battery. The use of the hollow bottom plate allows the cured solder paste or conductive glue to be embedded in the hollow groove, thereby ensuring the flatness of the contact surface between the front of the battery and the bottom plate, and reducing the risks of hidden cracks or poor printing of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0017] Figure 1 This is a welding flow chart of a battery without a main grid in the prior art;

[0018] Figure 2 It is a schematic diagram of the distribution of insulating glue points on the surface of a battery without a main grid in the prior art;

[0019] Figure 3 This is a welding flow chart of a main grid-free battery of the present invention;

[0020] Figure 4 A schematic diagram of the distribution of fine grid lines and solder paste or conductive glue on the surface of a busbar-free battery of the present invention;

[0021] Figure 5 It is a schematic diagram of the structure of the conventional bottom plate and the hollow bottom plate of the present invention. DETAILED DESCRIPTION

[0022] The following examples are used to explain the implementation methods of the present application in detail, so that the implementation process of how the present application uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0023] Example 1

[0024] A busbar-free battery welding method comprises the following steps:

[0025] (1) placing a busbar-free battery on a conventional base plate, and applying solder paste to the front of the busbar-free battery through a screen printing plate. The printed solder paste is distributed in strips on the front of the busbar-free battery so that it is perpendicular to the thin grid lines on the front of the battery. Then, heating and curing are performed to form a solid connection between the solder paste and the thin grid lines on the front;

[0026] (2) Flipping the busbar-free battery and placing it on a hollow bottom plate with its back facing upward, applying solder paste to the back of the busbar-free battery through a screen printing plate, and distributing the printed solder paste in strips on the back of the busbar-free battery so that it is perpendicular to the fine grid lines on the back of the battery, and then heating and curing it to form a solidified connection between the solder paste and the fine grid lines on the back;

[0027] (3) Lay the wire (lay the solder strip) in the area where the main grid battery is not coated with solder paste, and arrange them in sequence, and use a string soldering machine for soldering.

[0028] In this embodiment, a plurality of hollow grooves are formed on the surface of the hollow bottom plate, and the number of the hollow grooves is greater than the number of strip-shaped protrusions formed by the solder paste. The size (length, width) of the hollow grooves is greater than the size (length, width) of the strip-shaped protrusions formed by the solder paste to ensure that the strip-shaped protrusions formed on the front of the main grid-free battery completely enter the hollow grooves.

[0029] Example 2

[0030] A busbar-free battery welding method comprises the following steps:

[0031] (1) placing a busbar-free battery on a conventional base plate, and printing a conductive glue on the front of the busbar-free battery using a screen printing plate. The printed conductive glue is distributed in strips on the front of the busbar-free battery so that it is perpendicular to the thin grid lines on the front of the battery. Then, heating and curing are performed to form a solid connection between the conductive glue and the thin grid lines on the front;

[0032] (2) Flipping the busbar-free battery and placing it on the hollow bottom plate with its back facing upward, applying conductive glue to the back of the busbar-free battery through a printing screen, and distributing the printed conductive glue in strips on the back of the busbar-free battery so that it is perpendicular to the fine grid lines on the back of the battery, and then heating and curing it to form a solid connection between the conductive glue and the fine grid lines on the back;

[0033] (3) Lay the wire (lay the welding tape) in the conductive glue area without main grid battery printing, arrange them in sequence, and use a string welding machine for welding.

[0034] In this embodiment, a plurality of hollow grooves are formed on the surface of the hollow bottom plate, and the number of the hollow grooves is greater than the number of strip-shaped protrusions formed by the conductive adhesive. The size (length, width) of the hollow grooves is greater than the size (length, width) of the strip-shaped protrusions formed by the conductive adhesive, so as to ensure that the strip-shaped protrusions formed on the front of the main grid-free battery completely enter the hollow grooves.

[0035] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A main grid-free battery welding method, characterized in that: The following steps are involved: (1) Place the busbar-free battery on a conventional base plate, and apply solder paste or conductive glue to the front of the busbar-free battery through a screen printing plate so that it is perpendicular to the fine grid lines on the front of the battery; (2) Flip the busbar-free battery and place it on the hollow bottom plate with its back facing upwards, and apply solder paste or conductive glue on the back of the busbar-free battery through a printing screen so that it is perpendicular to the fine grid lines on the back of the battery; (3) Lay out wires in the areas where solder paste or conductive glue is printed without main grid cells, arrange them in sequence, and perform welding using a string welding machine.

2. The busbar-free battery welding method according to claim 1, characterized in that: In steps (1) and (2), the printed solder paste or conductive glue is distributed in strips on the surface of the battery without main grid.

3. The busbar-free battery welding method according to claim 1, characterized in that: In steps (1) and (2), after the solder paste or conductive adhesive is printed on the surface of the busbar-free battery, a heating and curing treatment is performed to allow the solder paste or conductive adhesive to form a cured connection with the fine grid lines.

4. The busbar-free battery welding method according to claim 1, characterized in that: In step (2), a plurality of groups of hollow grooves are formed on the surface of the hollow bottom plate, and the number of the hollow grooves is greater than the number of strip-shaped protrusions formed by the solder paste or the conductive adhesive.

5. The busbar-free battery welding method according to claim 4, characterized in that: The length and width of the hollow groove are greater than the length and width of the strip-shaped protrusion formed by the solder paste or the conductive glue.

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