Precise series connection method of solar cells

Abstract

A precise series connection method for solar cells is characterized by comprising the following steps: transferring to-be-connected cells with positioning points into an alignment platform; acquiring position information of the positioning point through a visual identification part; the alignment platform performs position correction on the battery pieces to be connected in series according to the position information; placing the battery pieces to be connected in series, which are subjected to position correction, on a string placing platform at a piece placing position through a battery carrying part; the string placing platform carries the battery pieces to be connected in series to move to a wire covering position; the conductive wires are laid on the surfaces of the battery pieces to be connected in series after passing through the positioning comb; fixing the conductive wires on the surfaces of the battery pieces to be connected in series; and cutting off the conductive wire at a preset disconnection position to prepare the precisely serially connected battery string. Through the synergistic effect of alignment platform correction and platform transportation, the carrying precision of the battery pieces is effectively improved, meanwhile, the placing precision of the welding strip is improved through the continuous wire covering and the cutting process between the battery pieces, and precise alignment between the welding strip and the battery pieces is achieved through synchronous improvement of the two kinds of precision.

Description

Technical Field

[0001] This invention belongs to the field of solar cell manufacturing, and particularly relates to a precise series connection method for solar cells. Background Technology

[0002] In the field of solar cell manufacturing, current stringing equipment mostly uses conveyor belts to transport solar cells, while the processing of the welding strip adopts a "cut first, then place" process. This process has the following problems: 1) Insufficient precision in handling solar cells; solar cells are easily affected by mechanical vibration, belt slippage, conveyor belt deviation, etc. during the transport process, resulting in positional deviation when they arrive at the welding station; 2) The welding strip is first cut to a preset length and then picked up and placed segment by segment by mechanical grippers. This process of cutting first and then placing has double errors in cutting and handling, resulting in a large deviation between the actual position of the welding strip and the theoretical path; 3) The superposition of errors in conveyor belt transport and segmented placement of welding strip results in poor alignment accuracy between the welding strip and the solar cell, which is not suitable for high-efficiency battery technologies such as stacked grid cells and back contact cells, which have strict requirements for welding strip-cell alignment accuracy. Summary of the Invention

[0003] The present invention aims to solve the above problems and provide a precision series connection method for solar cells that improves the accuracy of cell handling and ribbon placement.

[0004] The precise series connection method for solar cells according to the present invention includes the following steps: Step 1: Input the solar cells to be connected in series with the positioning points set into the alignment platform; obtain the position information of the positioning points through the vision recognition component; the alignment platform performs position correction on the solar cells to be connected in series based on the aforementioned position information; Step 2: Place the positioned and aligned battery cells to be connected in series onto the stringing platform located at the cell placement position using the battery transport component; Step 3: The stringing platform carries the battery cells to be connected in series to the wire-coating position; the conductive wire is laid on the surface of the battery cells to be connected in series after passing through the positioning comb. Step 4: Fix the aforementioned conductive wire to the surface of the battery cells to be connected in series; Step 5: Cut the conductive wire at the preset disconnect position to obtain a precisely connected battery string.

[0005] Furthermore, in the precise series connection method of the solar cells described in this invention, when the conductive wire is laid on the cells to be connected in series, one end of the conductive wire moves towards the cells to be connected in series located at the wire-covering position under the clamping of the conductive wire traction component; the conductive wire is calibrated in position by a positioning comb during the movement.

[0006] Furthermore, in the precision series connection method for solar cells described in this invention, when the conductive wire passes through the positioning comb for position calibration, the positioning comb is smooth on one side and closely adheres to the conductive wire for positioning. Conventional positioning methods function similarly to a comb, simply allowing the conductive wire to enter the positioning comb groove. In this invention, the conductive wire is positioned on one side when passing through the positioning comb, which further improves the accuracy of positioning.

[0007] Furthermore, in the precision series connection method of the solar cell described in this invention, the conductive wire is fixed by means of glue, adhesive film or welding; when welding is used for fixing, the welding method is infrared heating welding or direct heating welding by energizing the conductive wire.

[0008] Furthermore, in the precise series connection method of the solar cells described in this invention, the conductive wire is cut by laser cutting or arc cutting.

[0009] Furthermore, in the precision series connection method for solar cells described in this invention, the conductive wire is thinned or compressed at the cutting position. This thinning or compression process reduces the technological requirements of the cutting equipment, thereby enabling the copper wire to be cut better and faster, reducing cutting power, and improving stringing efficiency.

[0010] Furthermore, in the precision series connection method for solar cells described in this invention, a protective layer is provided on the edges of the solar cells to be connected in series on both sides of the cut position of the conductive wire. For solar cells with negative spacing, the conductive wire needs to be cut on the surface of the solar cell. A protective layer is pre-set on the solar cell below the cut position. By setting the protective layer, hard contact between the solder ribbon and the solar cell can be eliminated, the edge stress of the cell can be reduced, and the risk of edge microcracks during welding can be reduced; at the same time, the solar cell can be effectively protected to avoid damage during the cutting process. The protective layer is made of hot melt adhesive, thermosetting adhesive, insulating adhesive, etc.

[0011] The precision series connection method for solar cells described in this invention effectively improves the handling accuracy of solar cells through the synergistic effect of alignment platform correction and platform transportation. Simultaneously, the continuous wire coating and inter-cell cutting processes enhance the placement accuracy of the solder ribbon. This simultaneous improvement in both accuracies achieves precise alignment between the solder ribbon and the solar cells. Particularly in the fabrication of stacked grid solar modules, the conductive wires can be precisely placed on the fine grid lines of the solar cells. In this case, current transmission in the direction parallel to the solar cell surface primarily relies on the conductive wires, reducing the resistance requirement of the fine grid in this direction. Therefore, the fine grid can be thinned during fabrication, or non-silver paste can be used, thereby reducing silver consumption and module costs. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the precise series connection method for solar cells according to an embodiment of the present invention; Figure 2This is a schematic diagram of the positioning comb structure of the solar cell according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the series structure layout of a stacked-grid battery module according to an embodiment of the present invention; Figure 4 As described in the embodiments of the present invention Figure 3 A schematic diagram of the AA cross-sectional structure in the diagram; Figure 5 This is a schematic diagram of the series structure layout of a four-segment stacked battery as described in an embodiment of the present invention; Figure 6 As described in the embodiments of the present invention Figure 5 A schematic diagram of the AA cross-sectional structure in the diagram; Among them, 1-battery cell, 2-conductive wire, 3-positioning comb, 4-adhesive film, 5-cutting position, 6-fine grid, and 7-welding area. Detailed Implementation

[0013] The precise series connection method for solar cells of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0014] Example 1 This embodiment discloses a method for addressing, for example Figure 3 The precise series connection method of the stacked grid cell assembly shown is as follows: Figure 1 As shown, it includes the following steps: Step S1: The battery cell 1 to be connected in series with the mark points is transmitted to the alignment platform, and the mark point position information is obtained through the visual recognition component; the alignment platform performs position correction on the battery cell 1 to be connected in series according to the mark point position information. Step S2: The battery cell 1, which has been positioned and corrected, is precisely placed onto the stringing platform located at the cell placement position using the battery transport component; Step S3: The stringing platform carries the battery cell 1 to be connected in series to the wire-coating position; the conductive wire 2 is precisely laid on the surface of the aforementioned battery cell 1 by the positioning comb 3; Step S4: Fix the aforementioned conductive wire 2 to the surface of the battery cell 1 to be connected in series using the adhesive film 4; Step S5: Cut the conductive wire 2 at the point where it needs to be disconnected to obtain a precision series-connected battery string; Step S6: Remove the previously prepared precision series-connected battery string and move the string-swinging platform. Repeat steps S1-S5 to prepare the next set of battery strings.

[0015] In this embodiment, the conductive wire 2 traction component clamps one end of the conductive wire 2 and moves it towards the already placed battery cell 1; during the movement, the conductive wire 2 is positionally calibrated by the positioning comb 3; as... Figure 2As shown, when the conductive wire 2 passes through the positioning comb 3, the positioning comb 3 is smooth on one side and closely adheres to the conductive wire 2 for positioning. After the conductive wire 2 is pulled to a specified length (reaching the length of the placed battery cell 1), it is cut by laser cutting and precisely placed on the surface of the battery cell 1. In this embodiment, the conductive wire 2 is located directly above the fine grid 6 line of the battery cell 1.

[0016] The battery string obtained through steps S1-S5 of this embodiment is as follows: Figure 3 and Figure 4 As shown, the conductive wire 2 can be precisely positioned above the fine grid lines 6 of the solar cell 1, so that current conduction parallel to the cell surface mainly relies on the conductive wire 2, rather than the fine grid lines 6. In this cell string, the fine grid lines 6 are mainly used for current transmission perpendicular to the surface of the solar cell 1, while the resistance requirement in the direction parallel to the cell surface is greatly reduced. Therefore, the fine grid lines 6 can be coated with a thinner coating process during production, or a non-silver paste with low conductivity and lower cost can be used, thereby achieving the goal of significantly reducing silver consumption and reducing module cost.

[0017] Example 2 This embodiment discloses a method for addressing, for example Figure 5 The precise series connection method of the quad-cell stacked battery module shown is as follows: Figure 1 As shown, it includes the following steps: Step S1: The battery cell 1 to be connected in series with the mark points is transmitted to the alignment platform, and the mark point position information is obtained through the visual recognition component; the alignment platform performs position correction on the battery cell 1 to be connected in series according to the mark point position information. Step S2: The battery cell 1, which has been positioned and corrected, is precisely placed onto the stringing platform located at the cell placement position using the battery transport component; Step S3: The stringing platform carries the battery cell 1 to be connected in series to the wire-coating position; the conductive wire 2 is precisely laid on the surface of the aforementioned battery cell 1 by the positioning comb 3; Step S4: Fix the aforementioned conductive wire 2 to the surface of the battery cell 1 to be connected in series by welding; Step S5: Cut the conductive wire 2 at the point where it needs to be disconnected to obtain a precision series-connected battery string; Step S6: Remove the previously prepared precision series-connected battery string and move the string-swinging platform. Repeat steps S1-S5 to prepare the next set of battery strings.

[0018] In this embodiment, the conductive wire 2 is clamped at one end by the traction component and moved towards the placed battery cell 1. During the movement, the conductive wire 2 is calibrated by the positioning comb 3. After the conductive wire 2 is pulled to a specified length (reaching the length of the placed battery cell 1), it is cut by arc cutting and precisely placed on the surface of the battery cell 1. In this embodiment, the conductive wire 2 is located directly above the fine grid 6 line of the battery cell 1. The conductive wire 2 and the fine grid 6 are fixed together by welding. The conductive wire 2 is directly heated by electricity, that is, after heating, the outer layer of the conductive wire 2 melts and welds with the fine grid 6 in the welding area 7.

[0019] The battery string obtained through steps S31-35 of this embodiment is as follows: Figure 5 and Figure 6 As shown, the conductive wire 2 can be precisely positioned above the fine grid lines 6 of the solar cell 1, so that current conduction parallel to the cell surface mainly relies on the conductive wire 2, rather than the fine grid lines 6. In this cell string, the fine grid lines 6 are mainly used for current transmission perpendicular to the surface of the solar cell 1, while the resistance requirement in the direction parallel to the cell surface is greatly reduced. Therefore, the fine grid lines 6 can be coated with a thinner coating process during production, or a non-silver paste with low conductivity and lower cost can be used, thereby achieving the goal of significantly reducing silver consumption and reducing module cost.

[0020] In specific applications, for battery cells 1 with negative spacing, the conductive wire 2 needs to be cut on the surface of the battery cell 1 during the series connection process. Therefore, a protective layer is pre-set on the battery cell 1 below the cut position 5. By setting the protective layer, the hard contact between the solder ribbon and the battery cell 1 can be eliminated, the edge stress of the battery can be reduced, and the risk of edge microcracks during the welding process can be reduced; at the same time, the battery cell 1 can be effectively protected to avoid damage to it during the cutting process.

Claims

1. A method for precise series connection of solar cells, characterized in that... Includes the following steps: Step 1: Input the solar cells to be connected in series with the positioning points set into the alignment platform; obtain the position information of the positioning points through the vision recognition component; the alignment platform performs position correction on the solar cells to be connected in series based on the aforementioned position information; Step 2: Place the positioned and aligned battery cells to be connected in series onto the stringing platform located at the cell placement position using the battery transport component; Step 3: The stringing platform carries the battery cells to be connected in series to the wire-coating position; the conductive wire is laid on the surface of the battery cells to be connected in series after passing through the positioning comb. Step 4: Fix the aforementioned conductive wire to the surface of the battery cells to be connected in series; Step 5: Cut the conductive wire at the preset disconnect position to obtain a precisely connected battery string.

2. The precise series connection method for solar cells according to claim 1, characterized in that: When the conductive wire is laid on the battery cells to be connected in series, one end of the conductive wire is held by the conductive wire traction component and moves towards the battery cells to be connected in series at the wire-covering position; the conductive wire is calibrated by the positioning comb during the movement.

3. The precise series connection method for solar cells according to claim 2, characterized in that: When the conductive wire is calibrated by the positioning comb, the positioning comb is smooth on one side and fits tightly against the conductive wire for positioning.

4. The precise series connection method for solar cells according to claim 1 or 2, characterized in that: The conductive wire is fixed by means of glue, adhesive film or welding; When fixing is done by welding, the welding method is either infrared heating welding or direct heating welding by energizing the conductive wire.

5. The precise series connection method for solar cells according to claim 1 or 2, characterized in that: The conductive wire is cut by laser cutting or arc cutting.

6. The precise series connection method for solar cells according to claim 1 or 2, characterized in that: The conductive wire is thinned or compressed at the cut point.

7. The method for precise series connection of solar cells according to claim 1 or 2, characterized in that: A protective layer is provided on the edges of the battery cells to be connected in series on both sides of the cut position of the conductive wire.

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