CN108687418A - Solder strip connection method of solar cell - Google Patents

Abstract

The invention discloses a welding strip connecting method of a solar cell, which aims at the technical problems of more welding spots and high manufacturing cost in the converging welding process of a solar cell module in the prior art, and effectively reduces the traditional lamination welding workload of three-main-grid to five-main-grid modules by 60-80%, reduces the converging welding workload of the multi-main-grid modules by more than 90% and greatly reduces the manufacturing cost by the arrangement of the welding strip connecting method.

Description

A method for connecting solar cells with solder ribbons

technical field

The invention relates to a solar battery ribbon connection method, which is used for reducing the number of welding points during the solar battery welding process. The invention belongs to the technical field of solar cell production.

Background technique

Traditional solar cells usually have 3 to 5 busbars. The cells are picked up by the pick-up device after visual positioning and placed on the ribbon. After the battery is positioned, another row of interconnected ribbons is placed on the upper electrode. Under the drive, the batteries pass through infrared, electromagnetic induction, hot air and other heating elements in an orderly manner according to a certain beat and spacing, and the positive and negative electrodes of adjacent batteries are connected through interconnection strips, thereby realizing the series connection process of batteries. During the lamination welding process, the battery strings are usually placed on the interlayer film according to the spacing designed by the components. Under the action of the electric soldering iron, the battery strings are connected with the bus bar ribbon to realize the circuit connection between the battery strings. Take a typical 156×156mm three-busbar polycrystalline battery, 6 strings x 8 pieces/string module product as an example: Figure 1 shows the single-string battery after the string welding process is completed. In the figure, 1 is the three-bus grid cell; 2 is the first/second interconnecting ribbon; 3 is the first bus ribbon; subsequently, the single string of cells is converging to form a solar battery string as shown in Figure 2, in the figure, 3 is The first bus bar welding strip; 4 is the component lead wire welding strip; 5 is the new solder joint between the first interconnection bar and the first bus bar; 6 is the solder joint between the first bus bar and the lead wire. In the confluence process, the corresponding solder joints are still completed by manual welding in most factories, and the workload is very heavy. Even in the relatively simplified component connection scheme of the split junction box, the total number of solder joints in the confluence process is 42, of which: there are 36 solder joints between the bus bar and the interconnection bar, and there are 36 solder joints between the bus bar and the lead wire. 6, as shown in Figure 2.

With the development of high-efficiency battery component technology, multi-busbar technology will gradually become the mainstream of high-efficiency component technology in the future. The nominal maximum output power of multi-busbar solar cell modules can be increased by 2.5% to 3%. The number of busbars in a multi-busbar battery is usually 10 to 15. Taking a typical 12-bar battery as an example, if the above-mentioned traditional series welding method is still used, the single-string battery produced is shown in Figure 3. In the figure, 7 is a multi-busbar battery; The number of solder joints of the bus bar will change to 144, and the position of the newly added solder joints and the bus bar are marked with dots in the figure; the components are connected according to a relatively simplified split-type junction box, and the total number of solder joints is 150 , 6 of which are solder joints of bus bar leads, as shown in Figure 4. Moreover, after changing from 3 grids to 12 grids, the distance between adjacent interconnection bars and bus bars is shortened, and thermal interference will occur during the spot welding process; For a circular ribbon, the difficulty of welding is further increased, and the welding efficiency is reduced, resulting in a reduction in the efficiency of confluence welding to about 1/5~1/6 of the original. Therefore, for the promotion of multi-busbar technology, confluence welding will become a major bottleneck in the entire assembly process.

Therefore, it is necessary to design a solar cell welding method, reduce the number of solder joints in the solar cell welding process, improve production efficiency, and reduce production costs.

Contents of the invention

The present invention aims at the above-mentioned technical problems in the prior art, and provides a solar cell ribbon connection method, which effectively reduces the number of solder joints and reduces production costs.

For this reason, the present invention adopts following technical scheme:

A solar cell ribbon connection method, characterized in that a fixed-length bus bar is welded at the head end and/or tail end of a single battery string, and then a single string with a fixed-length bus bar is welded at the head end and/or tail end The battery strings are then welded to form the battery strings of photovoltaic modules.

Further, while the battery slices are connected in series, a fixed-length bus bar is welded at the head end and/or tail end of the single battery string.

Further, after the string welding of battery sheets is completed, fixed-length bus bars are welded at the head end and/or tail end of the single battery string.

Specifically, the solar cell ribbon connection method includes the following steps:

S1: Place the first bus bar with a fixed length on the preheating area of the transmission/welding platform of the stringing device, and the ribbon clamp grabs several first interconnecting bars that are consistent with the number of main grid electrodes of the cell The welding ribbon is placed on the first bus bar; or, the welding ribbon clamp grabs several first interconnecting strip welding ribbons that are consistent with the number of the main grid electrodes of the battery sheet and places them on the pre-set of the transmission/welding platform of the stringing device. placing a fixed-length first bus bar on top of said first interconnect ribbon on the hot zone;

S2: The manipulator picks up the first battery and places it on the first interconnection strip under the first bus bar, and each busbar electrode of the battery corresponds to the first interconnection strip;

S3: Place a number of second interconnection strips on the upper surface of the battery sheet that is consistent with the number of main grid electrodes of the battery sheet; one end of the second interconnection strip is located above one battery sheet, and the other end is located on the next one The lower part of the cell constitutes its first interconnection strip, so as to realize the series connection of the front and rear cells;

S4: Realize the connection of the first bus bar and the first interconnection strip through the heating element action area of the stringer; realize the welding of the first bus bar and the interconnection strip in the welding area of the stringer, and , Welding of interconnection strips and battery sheets;

S5: Repeat steps S2-S4 until the tail battery of the same row of cells, the second interconnection ribbon of the previous cell constitutes the first interconnection ribbon of the tail, and place the tail battery on it , place the second bus bar at the tail end of the tail battery, and then place several second interconnection strips on the upper surface of the tail battery that are consistent with the number of the main grid electrodes of the battery sheet. During the welding of the stringer area, to realize the welding of the second bus bar and the interconnection strip, and the welding of the interconnection strip and the battery sheet;

S6: For the single-string battery string formed after step S5, its head end and tail end are welded with fixed-length bus bars, and placed on the laminated film according to the spacing designed by the components. Under the action of the electric soldering iron, use the bus bar The battery strings are lap-welded by the welding ribbons to form the battery strings of the photovoltaic module.

Further, in step S1, the lower surface of the first bus bar contacts the bottom plate with heating function.

Further, in step S3, the battery sheet is compressed by the vacuum suction device on the transmission/welding platform of the stringing device to the interconnection ribbon located below it.

Further, in steps S1 and S5, the first bus bar, the second bus bar, and the first interconnection bar and the second interconnection bar are transported by the serial welding device/vacuum adsorption device or mechanically fixed on the welding platform fixed on the platform.

Further, the minimum length of the first bus bar and the second bus bar is the center-to-center distance L1 of the two outermost busbars of the standard cell in the module, and the maximum length is L1+2×L2. The placement of the first bus bar and the second bus bar is symmetrical on both sides relative to the center line of the battery sheet in the width direction.

Further, a pressing device is provided on the upper part of the welding area, and the pressing device presses the bus bar and the interconnecting strip, as well as the interconnecting strip and the battery sheet; after that, the heating element is used for heating, and then the heating When the component cools down, when the temperature of the solder joint drops below the melting point of the tinned coating of the bus bar, the pressing device is lifted to make the battery string continue to move forward.

Further, after the battery sheets are serially connected into a single battery string through the traditional serial welding process, an online or offline automatic welding device is used to weld the interconnection bar at the head end and/or tail end of the battery string and the fixed-length bus bar; After the internal bus bar is welded, each battery string is stacked and stacked and the ends of the bus bar are lapped and welded to form a battery string of photovoltaic modules. As a specific implementation manner, while the battery slices are connected in series, a fixed-length bus bar is welded at the head end and/or tail end of the single battery string.

The present invention has following beneficial effect:

The invention overcomes the disadvantages of many solder joints and high manufacturing cost in the confluence welding process of solar battery modules, can effectively reduce the stacked welding workload of traditional three-to-five-busbar components by 60% to 80%, and reduce the confluence of multi-busbar components The welding workload is more than 90%, which greatly reduces the manufacturing cost.

Description of drawings

Figure 1 is a single string of conventional batteries of three main grid batteries;

Figure 2 is a schematic diagram of conventional stack welding of three busbar battery components;

Figure 3 is a single string of a conventional battery of a multi-busbar battery;

Figure 4 is a schematic diagram of conventional stack welding of multi-busbar battery components;

Fig. 5 is a battery single string of the multi-busbar battery of the present invention;

Fig. 6 is a stacked schematic diagram of the multi-busbar battery assembly of the present invention; in the figure, the positions of the newly added welding points and the bus bar are marked with dots;

In the figure, 1 is a three-busbar battery; 2 is the first/second interconnection ribbon; 3 is the first bus bar ribbon; 4 is the component lead wire ribbon; 5 is the first interconnector and the first Newly added solder joints for the bus bar; 6 is the solder joint between the first bus bar and the lead wire; 7 is the multi-busbar battery; 8 is the overlapping solder joint of the adjacent single string of pre-welded bus bars.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example 1:

As shown in FIG. 5 and FIG. 6 , the multi-busbar battery 7 with 12 busbars is taken as the stringing object, and the traditional infrared heating stringer is used as the stringing equipment as an example for illustration.

In the present invention, the bus bar at the top of the first battery in a string of battery slices defines the first bus bar; the bus bar at the bottom of the tail battery in a string of battery slices defines the second bus bar, and the first bus bar is defined as the second bus bar. The bus bar and the second bus bar are collectively referred to as the bus bar; the interconnection ribbon on the back of the battery is defined as the first interconnection ribbon, and the interconnection ribbon on the front (light-receiving surface) of the battery is defined as the second The two interconnecting strips, the first interconnecting strips and the second interconnecting strips are collectively referred to as interconnecting strips; the set of all cells that are arranged in an orderly manner and form a photovoltaic module is a photovoltaic module. battery strings. The above definition is only for the convenience of description, not to limit its structure.

The ribbon connection method of the solar cell of the present embodiment comprises the following steps:

S1: Place the first bus bar 3 with a fixed length on the preheating area of the transmission/welding platform of the stringing device, and the ribbon clamp grabs several first interconnections that are consistent with the number of main grid electrodes of the cell The strip welding strip 2 is placed on the first bus bar;

The minimum length of the first bus bar and the second bus bar is the center-to-center distance L1 of the two outermost busbars of the standard cell in the module, and the maximum length is L1+2×L2; and the placement of the first bus bar is relatively The center line of the battery slices in the width direction is symmetrically arranged on both sides; the above-mentioned settings can ensure that there is enough length for overlapping when the subsequent stacking is confluenced, and the overlapping lengths of each row of battery strings are approximately equal; the lower part of the first bus bar 3 The surface is in contact with the bottom plate with heating function; to ensure the subsequent welding heat;

S2: The manipulator picks up the first battery, and places it on the first interconnection ribbon 2 below the first bus bar 3, and each main grid electrode of the battery corresponds to the first interconnection ribbon. In this embodiment, The number of the first interconnection ribbons 2 is 12;

S3: Place a number of second interconnection strips 2 on the upper surface of the battery sheet, which is consistent with the number of main grid electrodes of the battery sheet; one end of the second interconnection strip is located above a battery sheet, and the other end is located below The bottom of a cell constitutes its first interconnection strip, so as to realize the series connection of the front and rear cells;

S4: Realize the connection of the first bus bar and the first interconnection strip through the heating element action area of the stringer; realize the welding of the first bus bar and the interconnection strip in the welding area of the stringer, and , Welding of interconnection strips and battery sheets;

S5: Repeat steps S2-S4 until the tail battery of the same row of cells, the second interconnection ribbon of the previous cell constitutes the first interconnection ribbon of the tail, and place the tail battery on it , place the second bus bar at the tail end of the tail battery, and then place several second interconnection strips on the upper surface of the tail battery that are consistent with the number of the main grid electrodes of the battery sheet. During the welding of the stringer area, to realize the welding of the second bus bar and the interconnection strip, and the welding of the interconnection strip and the battery sheet;

S6: For the single-string battery string formed after step S5, its head end and tail end are welded with fixed-length bus bars, and placed on the laminated film according to the spacing designed by the components. Under the action of the electric soldering iron, use the bus bar The battery strings are lap-welded by the welding ribbons to form the battery strings of the photovoltaic module.

Using the solar cell ribbon connection method provided by the present invention, in the entire 6 strings of 12 main grid cell assemblies, the number of lap welding points 8 is only 5, plus 6 connection points where the lead wires and bus bar ribbons are welded, In the stacking process, the number of all solder joints is only 11. Compared with the conventional welding method shown in Figure 4, the number of solder joints is 144 plus 6 lead-out solder joints, a total of 150 stacked solder joints. , reduced by 92.7%, the resulting production efficiency increased by about 95%, and the manufacturing cost will be greatly reduced. If the length of the fixed-length bus bar welded at the end of a single string is close to the width of the cell, it is necessary to introduce short bus bars for auxiliary lap welding. , The number of solder joints at the overlapping position is changed from 5 to 10, and the total number of solder joints is changed to 16, so the production efficiency of the stack welding process is increased by 89%.

Example 2:

The difference between this embodiment and Embodiment 1 is that the solar cell ribbon connection method of the present invention is used in common three-bus, four-bus, and five-bus assemblies, and the steps are the same as those in Embodiment 1. .

After using the present invention, in the welding process of three main grids, four main grids and five main grid assemblies, the number of the most common stacked welding joints of 6 battery strings is reduced from 42, 54 and 66 to 11 respectively solder joints. The production efficiency of the stack welding process is increased by about 70~80%. If the third bus bar for auxiliary lap welding is introduced, the number of solder joints at the lap joint position will change from 5 to 10, and the total number of solder joints will become 16, so the production efficiency of the stack welding process will increase by about 60~75 %.

Example 3:

The difference between this embodiment and Embodiment 1 is that in step S1, firstly, the ribbon gripper grabs several interconnecting ribbons that are consistent with the number of the main grid electrodes of the cells and places them on the stringing device. On the preheated area of the transfer/soldering platform, a fixed length of the first bus bar is then placed on top of the interconnect ribbon. All the other steps are the same as in Example 1.

Example 4:

The difference between this embodiment and Embodiment 1 is:

After the battery slices are welded into a single battery string by the traditional string welding method, an on-line or off-line automatic welding device is used to weld the interconnection strips at the beginning and/or end of the battery string to the fixed-length bus bar; after the end bus bar is welded Then each battery string is stacked and stacked and the end of the bus bar is overlapped and welded to form a battery string of a photovoltaic module.

The specific embodiments described above have further described the technical problems, technical solutions and beneficial effects solved by the present invention in detail. It should be understood that the above descriptions are only specific embodiments of this patent and are not intended to limit this patent. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (10)

1. A solar battery ribbon connection method, characterized in that: fixed-length bus bars are welded at the head end and/or tail end of a single battery string, and then the head end and/or tail end have fixed-length bus bars The single-string battery strings are then welded to form the battery strings of photovoltaic modules. 2 . The solar cell ribbon connection method according to claim 1 , characterized in that: while the battery slices are connected in series, a fixed-length bus bar is welded at the head end and/or tail end of the single battery string. 3 . 3 . The solar cell ribbon connection method according to claim 1 , characterized in that: after the battery slices are connected in series, a fixed-length bus bar is welded at the head end and/or tail end of the single battery string. 4 . 4. The solar cell ribbon connection method according to claim 2, characterized in that: comprising the following steps: S1: Place the first bus bar with a fixed length on the preheating area of the transmission/welding platform of the stringing device, and the ribbon clamp grabs several first interconnecting bars that are consistent with the number of main grid electrodes of the cell The welding ribbon is placed on the first bus bar; or, the welding ribbon clamp grabs several first interconnecting strip welding ribbons that are consistent with the number of the main grid electrodes of the battery sheet and places them on the pre-set of the transmission/welding platform of the stringing device. placing a fixed-length first bus bar on top of said first interconnect ribbon on the hot zone; S2: The manipulator picks up the first battery and places it on the first interconnection strip under the first bus bar, and each busbar electrode of the battery corresponds to the first interconnection strip; S3: Place a number of second interconnection strips on the upper surface of the battery sheet that is consistent with the number of main grid electrodes of the battery sheet; one end of the second interconnection strip is located above one battery sheet, and the other end is located on the next one The lower part of the cell constitutes its first interconnection strip, so as to realize the series connection of the front and rear cells; S4: Realize the connection of the first bus bar and the first interconnection strip through the heating element action area of the stringer; realize the welding of the first bus bar and the interconnection strip in the welding area of the stringer, and , Welding of interconnection strips and battery sheets; S5: Repeat steps S2-S4 until the tail battery of the same row of cells, the second interconnection ribbon of the previous cell constitutes the first interconnection ribbon of the tail, and place the tail battery on it , place the second bus bar at the tail end of the tail battery, and then place several second interconnection strips on the upper surface of the tail battery that are consistent with the number of the main grid electrodes of the battery sheet. During the welding of the stringer area, to realize the welding of the second bus bar and the interconnection strip, and the welding of the interconnection strip and the battery sheet; S6: For the single-string battery string formed after step S5, its head end and tail end are welded with fixed-length bus bars, and placed on the laminated film according to the spacing designed by the components. Under the action of the electric soldering iron, use the bus bar The battery strings are lap-welded by the welding ribbons to form the battery strings of the photovoltaic module. 5 . The solar cell ribbon connection method according to claim 4 , characterized in that: in step S1 , the lower surface of the first bus bar contacts the bottom plate with heating function. 6 . 6. The solar cell ribbon connection method according to claim 4, characterized in that: in step S3, the battery slices are transported by the serial welding device/the vacuum adsorption device on the welding platform compresses the interconnection strips below it ribbon. 7. The solar cell ribbon connection method according to claim 4, characterized in that: in steps S1 and S5, the first bus bar, the second bus bar, and the first interconnection bar, the second interconnection The strips are fixed on the platform by the vacuum adsorption device on the transfer/welding platform of the serial welding device or by mechanical fixing. 8. The solar cell ribbon connection method according to claim 4, characterized in that: the minimum lengths of the first bus bar and the second bus bar are the two outermost bus bars of the standard cell in the module The center-to-center distance L1, the maximum length is L1+2×L2, and the placement of the first bus bar and the second bus bar is symmetrical on both sides relative to the center line of the battery sheet in the width direction. 9. The solar cell ribbon connection method according to claim 4, characterized in that: a pressing device is arranged on the upper part of the welding area, and the pressing device presses the bus bar and the interconnecting bar ribbon, and the interconnection The strip welding strip and the battery sheet; after that, the heating element is used for heating, and then the heating element cools down. When the temperature of the solder joint drops below the melting point of the tinned coating of the bus bar, the pressing device is lifted to make the battery string continue to move forward . 10. The solar cell ribbon connection method according to claim 3, characterized in that: after the cells are serially connected into a single battery string through the traditional string welding process, the battery string is first connected by using an on-line or off-line automatic welding device. The interconnection bar at the end and/or tail end is welded to the fixed-length bus bar; after the end bus bar welding is completed, each battery string is stacked and stacked and the end of the bus bar is lap-welded. When the length of the bar is small, the third bus bar needs to be lap-welded with the ends of the adjacent fixed-length bus bars between adjacent single-string bus bars on the same side to form a battery string of photovoltaic modules.