CN107342341B - Half solar cell module and welding method thereof - Google Patents

Abstract

The invention discloses a half-chip solar battery module and a welding method thereof. A bus bar perpendicular to the interconnection bar is welded on the interconnection bars at both ends of the battery string, so that the interconnection bars at the same end of the battery string pass through the bus bar. Connection; arrange two or more processed battery strings end-to-end to obtain a battery string series; arrange two or more battery string series side by side, and place between adjacent battery string series, And the bus bars at both ends of the battery string series are directly welded together or a lap welding bus bar for lap welding is added to weld the bus bars at the two ends to obtain a battery string unit; two or more battery string units are arranged side by side Arrange and weld the bus bars between the adjacent battery string units and at the end-to-end splicing of the battery string series directly or add a lap welding bus bar for lap welding. The invention greatly improves the production efficiency of the half-chip solar cell assembly.

Description

A half-chip solar cell module and welding method thereof

technical field

The invention belongs to the technical field of solar cell production and processing, and in particular relates to a half-chip solar cell assembly and a welding method thereof.

Background technique

A solar cell is a device that converts light energy into electrical energy by using the photoelectric effect or photochemical effect, also known as a solar chip or a photovoltaic cell. According to the different materials and technologies used, solar cells are mainly divided into two categories, one is crystalline silicon solar cells, and the other is thin-film solar cells. At present, no matter from the perspective of the global solar cell product structure, or from the perspective of China, which has the largest output of solar cells, crystalline silicon cells occupy an absolute advantage.

Most crystalline silicon solar cells have a metallized electrode consisting of a main grid and a sub-gate on the front, and a metallized back electrode containing only the main grid on the back, and the rest of the back is covered by a paste containing aluminum. The front main grid and sub-grid are usually arranged vertically in an H shape, and the sub-grid collects the current generated inside the battery, and then flows to the main grid. In order to reduce the amount of paste used for the busbars, the front and back busbars can be segmented or hollowed out in the middle. The back of the battery covered with aluminum paste is sintered at high temperature to form an aluminum-silicon alloy and an aluminum back field, which can reduce carrier recombination and improve battery efficiency.

Crystalline silicon solar cells and sliced cells are smaller cell units cut from a complete cell sheet. An assembly made of several sliced cells connected and packaged is called a sliced cell assembly. Compared with conventional components using unsliced batteries, sliced battery components can be superior to conventional components in terms of component current, component voltage, component area, component internal power loss, and component heat spot resistance due to the smaller cell area. components. For example, the battery is divided into two halves along the direction perpendicular to the main grid line, and then double the number of half-cell batteries are packaged to form a half-chip battery assembly. Since the current passing through each ribbon is only half of that of conventional components, it reduces the cost. The power loss caused by the Joule effect inside the module improves the conversion efficiency of the module. And because the power loss caused by the interconnection strips in the module becomes about 1/4 of that of the whole module, the power of the half-cell module will increase by about 2% compared with the same type of whole-cell module.

Figure 1 is a schematic diagram of the existing connection structure of a typical half-cell solar cell module based on five main grids (a typical connection method for 120 half-cell cells), in which the interconnection strips connected at the ends are marked, while the interconnection of other parts Strips or grid lines are simplified and omitted. As shown in Figure 1, in the stacking process of half-cell battery modules, more than half of the workload of welding and confluence of battery strings is in the middle of the module. It is already difficult to meet large-scale production lines by relying on traditional manual welding-based production lines. Production needs, where Figure 2 is a partial enlarged view of A and B. As shown in Figures 1 to 3, 1a is a half-cell battery, 2a is an interconnection bar, 3a is a bus bar, 4a is a lead wire, and 6a is the welding point between the interconnection bar 2a and the bus bar 3a. For the five-busbar half-cell solar cell module, the total number of solder joints to be welded is 126 during stack welding, of which 120 are solder joints for bus bars and interconnecting bars, and 6 are solder joints for lead wires. There are 66 welding spots in the middle, and 60 of them need to weld the interconnection strips to the common bus bar 3 in the middle. The number of solder joints in the stacking process of the standard five-busbar full-piece battery assembly is 64 (centralized junction box) or 66 (split junction box), and the solder joints are all located at the short side ends of the module. Therefore, after switching to the half-cut battery module design, the time-consuming of the stacking and welding process increases to 3 to 5 times that of the full-cut battery module. The production efficiency of the half-cut battery module is low, and the difficulty of stacking has become the main factor restricting the large-scale production of half-cut modules. bottleneck.

Contents of the invention

In order to solve the above problems, the present invention provides a welding method for a half-sheet solar cell assembly, which improves the production efficiency of the half-sheet solar cell assembly.

The technical solution of the present invention is: a welding method of a half-sheet solar cell module, comprising the following steps:

(1) Multiple half-cells are coupled in series by interconnecting bar welding to form a battery string;

(2) Weld a bus bar perpendicular to the interconnection bar on the interconnection bars at both ends of the battery string, so that the interconnection bars at the same end of the battery string are connected through the bus bar;

(3) Arranging two or more battery strings processed in step (2) in an end-to-end manner to obtain a series of battery strings;

(4) Arrange two or more battery string series side by side, and directly weld the bus bars between adjacent battery string series and at both ends of the battery string series or add a lap welding bus bar for lap welding Welding the bus bars at both ends to obtain a battery string unit;

(5) Arrange two or more battery string units side by side, and directly weld the bus bars between the adjacent battery string units and at the end-to-end splicing of the battery string series or add a lap welding bus for lap welding The strips are welded with lead wires to obtain the half-sheet solar cell module.

The present invention pre-welds the bus bars at both ends of the battery strings to connect the interconnection bars located at the same end of the battery strings. Based on the single strings that are pre-converged at the ends, during the stack welding process, the battery strings are designed according to the spacing of the components. Put them on the laminated film, and weld the battery strings together according to the method of the present invention. By adopting the welding method of the invention, the number of welding points in the lamination welding process can be reduced, the welding efficiency is greatly improved, and thus the production efficiency of the half-piece solar battery module is improved.

The part of the lap welding bus bar used for lap welding in the above steps (3) and (4) that exceeds the edge of the battery sheet is cut off to ensure that the components maintain a safe creepage distance and electrical clearance.

Preferably, the lengths of the bus bars are equal.

Preferably, the distance between the main grid lines on both sides of the half-cell on the half-cell is L1; in the battery string unit, the distance between adjacent electrodes between two half-cells arranged side by side is L2; the length of the bus bar is greater than L1 and less than L1+2×L2.

Preferably, the bus bars are symmetrically arranged with the central line in the width direction of the half-cell battery as an axis of symmetry. The bus bar is symmetrically arranged relative to the center axis of the half-cell battery. When welding by a welding machine, if the length of the bus bar is less than L1, it is not convenient to use the lap welding bus bar for welding by lap welding; if the length of the bus bar is greater than L1 When +2×L2, the length of the bus bar is too long, which causes waste of the bus bar and increases the manufacturing cost of the present invention.

Preferably, in the series of battery strings, the distance between the two bus bars at the end-to-end splicing of the battery strings is 0-20 mm.

Preferably, in the battery string unit, lead-out wires are respectively welded on the battery string series, and the lead-out wires are welded to two parallel bus bars located at the end-to-end joints in the battery string series.

Preferably, the half cell is a half cell including 2 to 5 busbars.

As a further preference, the half cell is a half cell including 5 busbars.

The present invention also provides a half-sheet solar cell assembly, which is obtained by welding the half-sheet solar cell assembly by the above-mentioned welding method. When preparing a half-sheet solar cell module, the welding process is carried out by using the welding method of the present invention, and finally a half-sheet solar cell module is prepared.

Compared with the prior art, the beneficial effects of the present invention are reflected in:

The invention can increase the stacking production efficiency of traditional half-cell battery components by 70% to 80%, and at the same time greatly reduce the possibility of hidden cracks in the stacking process of the traditional process, thereby greatly reducing the manufacturing cost. The scope of application of the invention is relatively large It can be extended to the welding of half solar cell modules with any number of busbars.

Description of drawings

Fig. 1 is a schematic diagram of stacked connections of traditional five-busbar half-cell battery components in the prior art.

FIG. 2 is a schematic diagram of an enlarged structure at point A in FIG. 1 .

FIG. 3 is a schematic diagram of an enlarged structure at B in FIG. 1 .

Fig. 4 is a schematic diagram of stacked connection of five busbar half-cell battery components in the present invention.

FIG. 5 is a schematic diagram of an enlarged structure at point C in FIG. 4 .

FIG. 6 is a schematic diagram of an enlarged structure at point D in FIG. 4 .

Fig. 7 is a schematic structural diagram of a battery string in the present invention.

Fig. 8 is a schematic structural diagram of the battery string series in the present invention.

FIG. 9 is a schematic structural diagram of a battery string unit in the present invention.

Detailed ways

Example 1

A method for welding a half-sheet solar cell assembly, comprising the following steps:

(1) A plurality of half-cell batteries 1 are connected in series by interconnecting bar welding to form a battery string (see Figure 7);

(2) Weld a bus bar 3 perpendicular to the interconnection bar on the interconnection bar 2 at both ends of the battery string, so that the interconnection bar 2 at the same end of the battery string is connected through the bus bar 3, wherein,

The lengths of the bus bars 3 are equal, and the bus bars 3 are arranged symmetrically with the center line in the width direction of the half-cell battery 1 as the axis of symmetry;

(3) Based on the single strings that are pre-converged at the ends, during the stacking welding process, the battery strings are placed on the laminated film according to the spacing designed by the components, and two or more batteries after step (2) are processed The strings are arranged in an end-to-end splicing manner to obtain a series of battery strings (see Figure 8);

(4) Arrange two or more battery string series side by side, and directly weld the bus bars 3 between adjacent battery string series and at both ends of the battery string series or add a lap welding bus for lap welding Weld the bus bars 3 at both ends to obtain the battery string unit (see Figure 9);

(5) Arrange two or more battery string units side by side, and directly weld the bus bar 3 between adjacent battery string units and at the end-to-end splicing of the battery string series or add a lap welding for lap welding The bus bar is welded; the distance between the main grid lines 11 on both sides of the half-cell 1 on the half-cell 1 is L1; in the battery string unit, the distance between the adjacent electrodes between two half-cells 1 The distance is L2; the length of the bus bar 3 is greater than L1 and less than L1+2×L2;

(6) In the battery string unit, the lead wires 4 are welded on the battery string series respectively, and the lead wires 4 are welded to the two parallel bus bars 3 at the end-to-end splice in the battery string series.

In this embodiment, a five-busbar half-cut solar cell assembly (including 120 half-cut cells) is taken as an example, as shown in Figures 5 and 6, where the reference numeral 5 in the figure indicates the connection between the bus bar 3 and the adjacent battery when stacked and welded. The welding point when the bus bar 3 on the string series is welded; the reference numeral 6 in the figure is the welding point of the bus bar 3 and the interconnection bar 2; 7 is the welding point of the bus bar 3 and the lead wire 4.

It can be seen from Fig. 4 to Fig. 6 that if the bus bar 3 itself is lap-welded, the number of solder joints is 10; if an auxiliary lap-weld bus bar is added, the number of welding strips is 20. The lead wire 4 is located in the middle of the module. Two rows of parallel bus bars with symmetrical upper and lower positions are welded together with one lead wire ribbon. The total number of welding points between the bus bar and the lead wire is 12.

Note: In the drawings of the present invention, the interconnecting strips connected at the ends are marked, while the interconnecting strips or grid lines in other parts are simplified and omitted.

Claims (8)

1. A welding method for a half-sheet solar cell module, comprising the following steps: (1) Multiple half-cells are coupled in series through interconnection bar welding to form a battery string; (2) Weld a bus bar perpendicular to the interconnection bar on the interconnection bars at both ends of the battery string, so that the interconnection bars at the same end of the battery string are connected through the bus bar; (3) Arranging two or more battery strings processed in step (2) in an end-to-end splicing manner to obtain a series of battery strings; (4) Arrange two or more battery string series side by side, and directly weld the bus bars between adjacent battery string series and at both ends of the battery string series or add a lap welding bus bar for lap welding Welding the bus bars at both ends to obtain a battery string unit; (5) Arrange two or more battery string units side by side, and directly weld the bus bars between adjacent battery string units and at the end-to-end splicing of the battery string series or add a lap welding bus for lap welding The strips are welded to obtain the half-sheet solar cell module; The distance between the main grid lines located on both sides of the half-cell on the half-cell is L1; in the battery string unit, the distance between adjacent electrodes between two half-cells arranged side by side is L2; The length of the bus bar is greater than L1 and less than L1+2×L2. 2 . The method for welding half-piece solar cell modules according to claim 1 , wherein the lengths of the bus bars are equal. 3 . 3 . The method for welding a half-cell solar cell module according to claim 1 , wherein the bus bars are arranged symmetrically with the center line in the width direction of the half-cell solar cell as an axis of symmetry. 4 . 4 . The method for welding half-cut solar cell modules according to claim 1 , wherein, in the series of battery strings, the distance between the two bus bars at the end-to-end splicing of the battery strings is 0-20 mm. 5. The welding method of a half-chip solar cell module as claimed in claim 1, wherein, in the battery string unit, lead wires are respectively welded on the battery string series, and the lead wires are welded at the beginning and end of the battery string series On the two parallel bus bars at the splice. 6 . The method for welding a half solar cell module according to claim 1 , wherein the half cell is a half cell including 2 to 5 busbars. 7 . 7 . The method for welding a half solar cell module according to claim 6 , wherein the half cell is a half cell including five busbars. 8 . 8. A half-cut solar cell module, characterized in that the half-cut solar cell module is welded by the welding method described in any one of claims 1-7.