Back contact solar photovoltaic cell welding method

Abstract

The invention discloses a back contact solar photovoltaic cell welding method, which comprises the following steps of S1, carrying out dispensing treatment on a cell piece before welding, and adding dispensing positions at different positions of a welding strip of the cell piece, so that the welding strip is preliminarily fixed; s2, the battery piece is moved to the position below a laser device, and welding machining is prepared; s3, laser parameters are set according to the material characteristics of the welding strip; s4, laser welding processing is carried out, a laser is controlled to act on the welding strip, tin on the surface layer of the welding strip is melted, and alloy is formed by the tin and the metal electrode at the bottom of the battery piece; and S5, taking out and storing the battery piece after the battery piece is cooled. According to the invention, through dispensing treatment before welding, battery piece warping caused by bending of the welding strip due to heating during welding is prevented; laser welding only acts on the welding strip, reheating of the battery piece can be effectively avoided, and efficiency loss is avoided; and meanwhile, when laser welding acts, temperature distribution is more uniform, precision is higher, the problems of welding deviation, non-uniformity, pseudo soldering or short circuit and the like are effectively avoided, and the welding yield is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic cell manufacturing, and particularly relates to a welding method for back-contact solar photovoltaic cells. Background Art

[0002] The main-grid-free technology has great potential in terms of the energy conversion efficiency of solar energy and has received increasing attention in the photovoltaic field in recent years. However, when welding components of main-grid-free solar cells, due to their numerous and thin fine grids, when traditional welding is infrared thermal welding, there may be uneven temperature distribution during external heating, resulting in uneven welding, which is prone to cause virtual soldering or short circuit, and the welding tensile force is relatively low, affecting the component efficiency and manufacturing process. Infrared welding heats the entire cell, which will reduce the cell efficiency; the fixing ability of the solder tape on the cell is weakened, often causing the solder tape to shift after lamination, or the solder joint to become loose under the action of thermal stress or mechanical stress during the later use of the component. When welding back-contact solar components using the main-grid-free technology, the cell will warp after welding due to excessive temperature and too large bending hardness of the solder tape.

[0003] Based on the above problems, it is necessary to propose a welding method for back-contact solar photovoltaic cells to solve the above problems. Summary of the Invention

[0004] The purpose of the present invention is to provide a welding method for back-contact solar photovoltaic cells, which prevents the solder tape from warping due to heat bending during welding, can effectively avoid reheating the cell, avoid efficiency loss, and at the same time, the temperature distribution is more uniform and the accuracy is higher, effectively avoiding problems such as welding offset, unevenness, virtual soldering or short circuit, thereby avoiding rework and improving the welding yield.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A welding method for back-contact solar photovoltaic cells, comprising the following steps:

[0007] S1, perform glue-dotting treatment on the cell to be processed before welding, add glue-dotting positions at different positions of its solder tape to preliminarily fix the solder tape;

[0008] S2, move the cell to below the laser and prepare for welding processing;

[0009] S3, set laser parameters according to the material characteristics of the solder tape;

[0010] S4, perform laser welding processing, control the laser welding to act on the solder tape, melt the tin on the surface layer of the solder tape, and form an alloy with the metal electrode at the bottom of the cell;

[0011] S5, take out and store the processed cell after cooling.

[0012] In a preferred solution, in step S1, the dispensing positions on the solder tape are arranged at intervals according to the length of the solder tape.

[0013] In a preferred solution, in step S1, the fixed shape of the dispensing on the solder tape is one of a circle, a rhombus, a square, a hexagon or other similar shapes.

[0014] In a preferred solution, in step S1, the size of the dispensing on the solder tape is set according to the width of the solder tape of the actual cell.

[0015] In a preferred solution, in step S2, the selection of the laser type and the size of the laser spot are set according to the actual situation.

[0016] In a preferred solution, in step S2, an infrared nanosecond laser or a green nanosecond laser is selected, the laser spot is a rectangular spot, and at least one side dimension is the same as the projected width or diameter of the solder tape.

[0017] In a preferred solution, in step S3, the laser parameters include but are not limited to the linear velocity, frequency and power.

[0018] In a preferred solution, in step S4, the laser welding of the laser is controlled to act only on the solder tape to avoid reheating the cell.

[0019] Due to the application of the above technical solutions, the beneficial effects of the present application compared with the prior art are as follows:

[0020] A back-contact solar photovoltaic cell welding method provided by the present application solves the problems in the prior art through dispensing and laser welding: dispensing treatment is carried out before welding to prevent the solder tape from bending due to heat during welding, resulting in warping of the cell; laser welding acts only on the solder tape, which can effectively avoid reheating the cell and avoid efficiency loss; at the same time, when laser welding acts, the temperature distribution is more uniform and the precision is higher, effectively avoiding problems such as welding offset, unevenness, false soldering or short circuit, thereby avoiding rework and improving the welding yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0022] Figure 1 It is a flow chart of the back-contact solar photovoltaic cell welding method of the present invention;

[0023] Figure 2 Specific processing schematic diagram of the welding method for the back-contact solar photovoltaic cell of the present invention;

[0024] Figure 3 Schematic diagram of the dispensing shape of the welding method for the back-contact solar photovoltaic cell of the present invention. Specific embodiments

[0025] In order to enable those skilled in the art of the present technology to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present application.

[0026] It should be noted that the terms "first", "second", etc. in the description and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so as to describe the embodiments of the present application herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0027] In the present application, the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", etc. is based on the orientation or positional relationship shown in the accompanying drawings. These terms are mainly used to better describe the present invention and its embodiments, and are not used to limit that the indicated devices, elements or components must have a specific orientation or be constructed and operated in a specific orientation.

[0028] Moreover, in addition to being able to represent the orientation or positional relationship, some of the above terms may also be used to represent other meanings. For example, the term "upper" may also be used to represent a certain attachment relationship or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in the present invention can be understood according to specific circumstances.

[0029] In addition, the terms "installed", "set up", "provided with", "connected", "linked", and "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or there can be internal communication between two devices, components, or parts. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The following will detail this application with reference to the drawings and in combination with the embodiments.

[0031] Embodiment 1

[0032] As shown in the Figure 1 accompanying drawings, a welding method for a back-contact solar photovoltaic cell includes the following steps:

[0033] S1. Before welding the battery cell to be processed, perform glue-dotting treatment, add glue-dotting positions at different positions of its welding tape, so that the welding tape is preliminarily fixed;

[0034] S2. Move the battery cell under the laser, and prepare for welding processing;

[0035] S3. Set the laser parameters according to the material characteristics of the welding tape;

[0036] S4. Perform laser welding processing, control the laser welding to act on the welding tape, melt the tin on the surface layer of the welding tape, and form an alloy with the metal electrode at the bottom of the battery cell;

[0037] S5. After cooling the processed battery cell, take it out and store it.

[0038] Embodiment 2

[0039] As shown in the Figure 2 and 3 accompanying drawings, a welding method for a back-contact solar photovoltaic cell includes the following steps:

[0040] S1. Before welding the battery cell to be processed, perform glue-dotting treatment, add glue-dotting positions at different positions of its welding tape, so that the welding tape is preliminarily fixed, so that it will not cause stress changes due to the heat of the welding tape during the initial laser welding, resulting in the bending and offset of the welding tape; Specifically, the glue-dotting positions on the welding tape are arranged at intervals according to the length of the welding tape. Since the number of welding tapes is limited, the laser scanning path is less, and the action time is short, generally only dozens of milliseconds, it is not easy to damage the battery cell; the fixed shape of the glue dots on the welding tape is one of a circle, a rhombus, a square, a hexagon, or other similar shapes; the size of the glue dots on the welding tape is set according to the actual width of the welding tape of the battery cell;

[0041] S2. Move the solar cell under the laser, and prepare for welding process. Specifically, the selection of the laser type and the spot size is set according to the actual situation. The laser is selected as an infrared nanosecond laser or a green nanosecond laser. The spot is a rectangular spot, and at least one side dimension is the same as the projected width or diameter of the solder tape, ensuring that the laser does not scan the battery surface and cause damage to the solar cell.

[0042] S3. Set the laser parameters according to the material properties of the solder tape. The laser parameters include but are not limited to the linear velocity, frequency, and power.

[0043] S4. Perform laser welding process, control the laser welding to act on the solder tape, melt the tin on the surface of the solder tape, and form an alloy with the metal electrode at the bottom of the solar cell. Specifically, control the laser welding to only act on the solder tape, avoid reheating the solar cell, and avoid efficiency loss.

[0044] S5. Take out and store the processed solar cell after cooling.

[0045] A back-contact solar photovoltaic cell welding method provided by the present application solves the problems in the prior art through dispensing and laser welding. Before welding, dispensing treatment is carried out to prevent the solder tape from bending due to heat during welding, resulting in warping of the solar cell. Laser welding only acts on the solder tape, which can effectively avoid reheating the solar cell and avoid efficiency loss. At the same time, when laser welding acts, the temperature distribution is more uniform and the precision is higher, effectively avoiding problems such as welding deviation, non-uniformity, false soldering, or short circuit, thereby avoiding rework and improving the welding yield.

[0046] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. 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

1. A back contact solar photovoltaic cell welding method, characterized in that: The steps include: S1, before welding the battery cell to be processed, glue is applied, and glue spots are added at different positions of the welding strip to preliminarily fix the welding strip; S2, move the cell under the laser to prepare for welding; S3, setting laser parameters according to the material characteristics of the welding strip; S4, performing laser welding processing, controlling the laser welding to act on the welding strip, so that the tin on the surface of the welding strip melts and forms an alloy with the metal electrode at the bottom of the battery cell; S5, cooling the processed battery cells and taking them out and storing them.

2. The back contact solar photovoltaic cell welding method according to claim 1, characterized in that: In step S1, the glue dispensing positions on the soldering ribbon are arranged at intervals according to the length of the soldering ribbon.

3. The back contact solar photovoltaic cell welding method according to claim 1, characterized in that: In step S1 , the fixed shape of the glue dots on the soldering ribbon is a circle, a diamond, a square, a hexagon or other similar shapes.

4. The back contact solar photovoltaic cell welding method according to claim 1, characterized in that: In step S1 , the size of the glue dots on the soldering ribbon is set according to the actual width of the soldering ribbon of the battery cell.

5. The back contact solar photovoltaic cell welding method according to claim 1, characterized in that: In step S2, the laser type and the spot size are selected and set according to the actual situation.

6. The back contact solar photovoltaic cell welding method according to claim 5, characterized in that: In step S2, the laser is an infrared nanosecond laser or a green nanosecond laser, the light spot is a rectangular spot, and the size of at least one side is consistent with the projection width or diameter of the welding strip.

7. The back contact solar photovoltaic cell welding method according to claim 1, characterized in that: In step S3, laser parameters include but are not limited to line speed, frequency and power.

8. The back contact solar photovoltaic cell welding method according to claim 1, characterized in that: In step S4, the laser welding is controlled to act only on the welding strip to avoid reheating the battery cell.

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