Electromagnetic welding head

Abstract

The present application relates to a kind of electromagnetic welding head, the electromagnetic welding head includes middle magnetic core and the side magnetic core spaced apart in the one side of middle magnetic core, coil is wound on middle magnetic core, coil is configured to generate magnetic field after energization.Middle magnetic core is contacted with welding position when electromagnetic welding, and side magnetic core is used to generate the induced electromotive force in the opposite direction of middle magnetic core, to avoid product being burnt.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electromagnetic welding, in particular to an electromagnetic welding head. BACKGROUND

[0002] In the existing photovoltaic busbar welding technology, the electromagnetic welding is used to weld the busbar and the welding strip together, and when the welding power is too large and / or the welding time is too long, the welding strip is prone to be burnt off. SUMMARY

[0003] Therefore, the present application aims to provide an electromagnetic welding head which can effectively avoid the product from being burnt during welding.

[0004] The electromagnetic welding head of the present application comprises a middle magnetic core, a coil wound on the middle magnetic core, and a side magnetic core arranged at one side of the middle magnetic core.

[0005] In some embodiments, the middle magnetic core is arranged to weld a busbar and a welding strip, wherein the busbar is provided with photovoltaic cell pieces at the side, the welding strip is located on the photovoltaic cell pieces and extends to the busbar, the photovoltaic cell pieces are also provided with grid lines electrically connected with the welding strip, the busbar, the welding strip and the grid lines form a conductive branch, and the side magnetic core is arranged to excite an induced current in the conductive branch.

[0006] In some embodiments, the coil is located at one end of the middle magnetic core facing the busbar.

[0007] In some embodiments, the middle magnetic core and the side magnetic core are plate-shaped, and the middle magnetic core and the side magnetic core are arranged in parallel with each other; the electromagnetic welding head further comprises a first top magnetic core located at one side of the middle magnetic core and the side magnetic core and fixedly connected with the middle magnetic core and the side magnetic core.

[0008] In some embodiments, the first top magnetic core is arranged perpendicularly to the middle magnetic core and the side magnetic core.

[0009] In some embodiments, the middle magnetic core, the side magnetic core and the first top magnetic core are integrally formed.

[0010] In some embodiments, the middle magnetic core is cylindrical, and the side magnetic core is curved and plate-shaped; the electromagnetic welding head further comprises a second top magnetic core which is circular and plate-shaped, located at one side of the middle magnetic core and the side magnetic core, and fixedly connected with the middle magnetic core and the side magnetic core.

[0011] In some embodiments, the middle magnetic core, the side magnetic core and the second top magnetic core are integrally formed.

[0012] In some embodiments, two side magnetic cores are provided, and the two side magnetic cores are located on opposite sides of the middle magnetic core and are spaced apart.

[0013] In some embodiments, the coil is a Litz coil.

[0014] The electromagnetic welding head of the embodiments of the present application generates an induced electromotive force in the opposite direction of the middle magnetic core through the side magnetic core during electromagnetic welding, thereby avoiding the product from being burnt. BRIEF DESCRIPTION OF DRAWINGS

[0015] The above and other objects, features and advantages of the present application will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which:

[0016] Figure 1 FIG. 1 is a side view of an electromagnetic welding head according to a first embodiment of the present application;

[0017] Figure 2 FIG. 2 is a top view of the electromagnetic welding head according to the first embodiment of the present application;

[0018] Figure 3 FIG. 3 is a schematic view of an exemplary photovoltaic module suitable for welding by the electromagnetic welding head according to the embodiments of the present application;

[0019] Figure 4 FIG. 4 is a schematic view of a product welded by the electromagnetic welding head according to the first embodiment of the present application. DETAILED DESCRIPTION

[0020] The present application is described herein below based on embodiments, but the present application is not limited to only these embodiments. In the following detailed description of the present application, some specific details are described in detail. The present application can also be completely understood without the description of these details by those skilled in the art. In order to avoid confusion of the essence of the present application, well-known methods, processes, procedures, elements and circuits are not described in detail.

[0021] In addition, those of ordinary skill in the art will understand that the drawings provided herein are for illustrative purposes only and are not necessarily drawn to scale.

[0022] Meanwhile, it should be understood that in the following description, "circuit" refers to a conductive loop formed by at least one element or sub-circuit through electrical or electromagnetic connection. When an element or circuit is said to be "connected to" another element or said to be "connected between" two nodes, it can be directly coupled or connected to another element or there can be intermediate elements between the elements, and the connection between the elements can be physical, logical, or a combination thereof. On the contrary, when an element is said to be "directly coupled to" or "directly connected to" another element, it means that there is no intermediate element between the two.

[0023] Unless the context clearly requires otherwise, throughout the description, the words "comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to".

[0024] In the description of the application, it should be understood that the terms "first", "second" and the like are used only for descriptive purposes and are not to be construed as indicating or implying relative importance. In addition, in the description of the application, the meaning of "a plurality of" is two or more, unless otherwise stated.

[0025] First, refer to Figure 3 , the principle of photovoltaic power generation is generally that one side of the bus bar 4 is provided with a photovoltaic cell 6, and a plurality of photovoltaic components (not shown in the figure) are arranged on the photovoltaic cell 6, the photovoltaic components are used to convert light energy into electrical energy, the photovoltaic cell also has a solder strip 5 (single-dot dashed line) and a grid line 7 (double-dot dashed line), the solder strip 5 and the grid line 7 can have a plurality of, and the solder strip 5 is electrically connected with the grid line 7 respectively, the solder strip 5 is connected to the bus bar 4 by extending from the photovoltaic cell 6, the grid line 7 is located on the photovoltaic cell 6, the electrical energy generated by the photovoltaic components is conducted to each solder strip 5 through the grid line 7 distributed on the photovoltaic cell 6, and the solder strip 5 conducts the current to the bus bar 4, and the bus bar 4 collects the current to other electronic components (not shown in the figure).

[0026] The solder strip 5 and the bus bar 4 are usually welded together, and the existing electromagnetic welding head is usually a structure in which a coil is sleeved on a magnetic core, the magnetic core is used to press the solder strip 5 to the bus bar 4, the coil on the magnetic core is energized to generate a magnetic field, and eddy current is generated in the bus bar 4 and heat is generated, thereby welding the solder strip 5 and the bus bar 4 together. However, when electromagnetic welding is performed, in addition to the eddy current generated in the bus bar 4 for welding, an induced current is also generated in the parallel branch composed of the bus bar 4, the solder strip 5 and the grid line 7, and when the welding power is too large and / or the welding time is too long, the current in the parallel branch has the risk of burning out the solder strip 5 due to the poor current resistance of the solder strip 5. The electromagnetic welding head provided by the embodiment of the application can be used for welding the solder strip 5 and the bus bar 4:

[0027] Figure 1 This is a side view schematic diagram of the electromagnetic welding head of the first embodiment of the application. The schematic diagrams of the electromagnetic welding head of the first embodiment of the application in the left view and the right view are symmetrical. As shown in Figure 1 , the electromagnetic welding head comprises a middle magnetic core 1 and a side magnetic core 3 arranged at one side of the middle magnetic core 1. A coil 2 is wound on the middle magnetic core 1, and the coil 2 is configured to generate a magnetic field after being energized.

[0028] As Figure 1 , Figure 3 , and Figure 4As shown, the solder ribbon 5 (single-dot dashed line) extends from the photovoltaic cell 6 and connects to the busbar 4. The electromagnetic welding head in this embodiment can be used for welding the solder ribbon 5 to the busbar 4. During welding, the central magnetic core 1 presses the end of the solder ribbon 5 to fix it on the busbar 4 (see...). Figure 4 And energize coil 2 with alternating current, thereby generating a magnetic field B1 in space based on electromagnetic induction coil 2 (see...). Figure 3 The magnetic field B1 generates eddy currents I1 (dashed line) within busbar 4. The heat generated by current I1 is used to weld the solder ribbon 5 and busbar 4. However, since the solder ribbon 5 is also pressed against busbar 4, current I2 (solid line) also flows in the branch consisting of the solder ribbon 5 and the grid line 7 (double-dotted line), which is connected in parallel with current I1. Current I2 can cause the solder ribbon 5 to burn out, especially the section of the solder ribbon 5 that is suspended between the photovoltaic cell 6 and the busbar 4, which is more prone to burnout.

[0029] in, Figure 3 The direction of the magnetic field B1 is indicated by several dots, which represent a direction perpendicular to the diagram and pointing towards the reader. It should be understood that, due to different winding directions of coil 2, the direction of the magnetic field B1 can be either perpendicular to the diagram and pointing towards the reader, or perpendicular to the diagram and away from the reader. For illustrative purposes, this embodiment adopts one of these directions. In actual practice, the direction of the magnetic field B1 can also be opposite to that in this embodiment. Figure 4 This is a schematic diagram of an electromagnetic welding joint. Figure 4 In the process, one end of the solder strip 5 extending onto the busbar 4 is raised. The raised portion is pressed onto the busbar 4 by the central magnetic core 1 during welding. Furthermore, the raised portion is welded to the busbar 4 under the heat of the current I1, thereby making the solder strip 5 welded to the busbar 4.

[0030] like Figure 3 As shown, in this embodiment, when current I2 is generated in the parallel branch containing solder ribbon 5 and grid line 7, the electromagnetic induction side core 3 generates a reverse magnetic field B2 in space, which in turn generates an induced current (not shown in the figure) in the parallel branch containing solder ribbon 5 and grid line 7 in the opposite direction to current I2. This at least partially cancels out current I2, making current I2 insufficient to burn out solder ribbon 5. Figure 3 The direction of the magnetic field B2 is shown in several forks, representing the direction perpendicular to the plane away from the reader. That is, regardless of the winding direction of coil 2, the directions of magnetic fields B1 and B2 are always opposite, and the induced currents generated by them in the parallel branch formed by the solder ribbon 5 and the grid line 7 can at least partially cancel each other out, thereby protecting the solder ribbon 5 from burning out due to excessive current I2.

[0031] It should be noted that, in Figure 3Only one possible branch of current I2 (hereinafter referred to as I2 branch) is shown, but the I2 branch can have several branches (two or more). For example, referring to Figure 3 , the photovoltaic cell 6 has a plurality of transversely arranged grid lines 7 and a plurality of vertically arranged solder strips 5, each solder strip 5 is electrically connected to each grid line 7, and each grid line 7 is electrically connected to each solder strip 5. The photovoltaic cell 6 also has at least one photovoltaic component (not shown in the figure) for converting light energy into electrical energy, and each of the photovoltaic components is electrically connected to at least one grid line 7. The grid line 7 can conduct the electrical energy collected by the photovoltaic component in the form of current to the corresponding solder strip 5, the solder strip 5 can collect and conduct the current in the grid line 7 to the bus bar 4, and the bus bar 4 can conduct the current in the solder strip 5 to other components (not shown in the figure). Therefore, it is easy to understand that each grid line 7 can form an I2 conductive branch with any two solder strips 5, and the solder strip 5 in the current conduction state has the risk of being burned out. Among them, Figure 3 , the solder strip 5 is shown to have five, and the grid line 7 is shown to have ten, which is only for illustration, as known to those skilled in the art, in actual situations, the number of solder strips 5 and grid lines 7 on the photovoltaic cell 6 can be any number (two or more).

[0032] As shown in Figure 1 , in some embodiments, the coil 2 is located at one end of the middle magnetic core 1 facing the bus bar 4. This makes the magnetic field generated by the coil 2 after being energized have a higher induced current intensity in the bus bar 4, and the heat generated at the welding site is higher, which helps to improve the welding efficiency.

[0033] As shown in Figure 1 , in some embodiments, the side magnetic core 3 is provided with two, and the two side magnetic cores 3 are respectively located on opposite sides of the middle magnetic core 1, and the two side magnetic cores 3 are spaced apart. This is corresponding to the photovoltaic power generation equipment in which the photovoltaic cell 6 is provided on both sides of the bus bar 4, and Figure 3 , only the photovoltaic cell 6 is shown on one side of the bus bar 4 in the actual situation, the other side of the photovoltaic cell 6 can also be provided with a photovoltaic cell 6, and the photovoltaic cell 6 on both sides of the bus bar 4 has the same arrangement of solder strips 5 and grid lines 7. Therefore, the side magnetic core 3 on both sides of the middle magnetic core 1 generates a reverse induced electromotive force in the I2 conductive branch on both sides of the bus bar 4, thereby avoiding the solder strip 5 from being burned out.

[0034] That is, the photovoltaic power generation equipment (not shown) includes a form in which the photovoltaic cell 6, the solder strip 5 and the grid line 7 assembly are provided on both sides of the bus bar 4, or also includes a form in which the photovoltaic cell 6, the solder strip 5 and the grid line 7 assembly are provided on one side of the bus bar 4. Correspondingly, the side magnetic core 3 can also be provided in two forms, one on one side of the middle magnetic core 1, or one on each of the opposite sides of the middle magnetic core 1.

[0035] like Figure 1 As shown, in some embodiments, the central magnetic core 1 and the side magnetic core 3 are plate-shaped and arranged parallel to each other. The electromagnetic welding head also includes a first top magnetic core 8, which is located on one side of the central magnetic core 1 and the side magnetic core 3 and is fixedly connected to the central magnetic core 1 and the side magnetic core 3. In other words, as those skilled in the art will know, this is similar to the structure of an E-type magnetic core. The electromagnetic welding head can be connected to other structures of the electromagnetic welding head through the first top magnetic core 8, and the plate-shaped central magnetic core 1 and side magnetic core 3 are simple to manufacture and have low cost, and the winding of the coil 2 is also relatively simple.

[0036] Furthermore, in some embodiments, the first top magnetic core 8 is arranged perpendicularly to the middle magnetic core 1 and the side magnetic core 3, which can make the magnetic field generated by the magnetic core in space more uniform and the magnetic conduction effect better.

[0037] The central magnetic core 1, the side magnetic core 3, and the first top magnetic core 8 can be integrally formed or assembled from individual parts. Integral forming improves the structural strength and lifespan of the electromagnetic welding head. Assembling the parts, using adhesive bonding, reduces the processing difficulty and production cost of the electromagnetic welding head. The choice can be made based on actual needs.

[0038] Figure 2 This is a top view schematic diagram of the electromagnetic welding head according to the second embodiment of the present invention. Figure 2 As shown, the difference between the electromagnetic welding head in this embodiment and the electromagnetic welding head in the first embodiment is that the middle magnetic core 1 in this embodiment is cylindrical, and the side magnetic core 3 is curved and sheet-like. Furthermore, the electromagnetic welding head in this embodiment includes a disc-shaped second top magnetic core 9, which is located on one side of the middle magnetic core 1 and the side magnetic core 3 and is fixedly connected to them. In other words, as those skilled in the art will know, this is similar to a can-shaped magnetic core structure. Can-shaped magnetic cores offer better electromagnetic shielding.

[0039] In other alternative implementations, the side magnetic cores 3 can be multiple and plate-shaped, arranged in a ring surrounding the central magnetic core 1. Each adjacent plate-shaped side magnetic core 3 can be interconnected or spaced apart, thus achieving good electromagnetic shielding. The spaced intervals (i.e., gaps) between adjacent side magnetic cores 3 facilitate winding the coil 2 into the central magnetic core 1, allowing the wire to enter the core through the gaps and be wound.

[0040] The electromagnetic welding head in this embodiment can also be integrally formed, or it can be formed by connecting the middle magnetic core 1, the side magnetic core 3, and the second top magnetic core 9.

[0041] like Figure 2As shown, the edge magnetic core 3 of the embodiment can also have two, and are located on both sides of the middle magnetic core 1, and the two edge magnetic cores 3 are circumferentially arranged around the middle magnetic core 1, and the two edge magnetic cores 3 are spaced apart. Similar to the electromagnetic welding head of the first embodiment, this is corresponding to the photovoltaic device that the bus bar 4 is provided with the photovoltaic cell 6 on both sides.

[0042] The coil 2 of the embodiment can be a litz wire coil or a copper coil. Preferably, it is a litz wire coil, and the litz wire is a kind of wire made of a plurality of independently insulated conductors. The litz wire coil is simple to wind, can effectively reduce the high-frequency skin effect or proximity effect, thereby reducing the loss, and has high transmission efficiency.

[0043] The electromagnetic welding head of the embodiment can weld the product through the middle magnetic core, and can avoid the product from being burned by generating the induced electromotive force in the opposite direction of the middle magnetic core through the edge magnetic core, so as to ensure the welding quality of the product.

[0044] The above only describes the preferred embodiments of the present application, and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An electromagnetic welding head, characterized by The electromagnetic welding head comprises: A middle magnetic core (1) is provided with a coil (2) wound thereon, and the middle magnetic core (1) is arranged to weld a bus bar (4) and a welding strip (5), wherein the bus bar (4) is provided with a photovoltaic cell (6) on a side thereof, the welding strip (5) is located on the photovoltaic cell (6) and extends to the bus bar (4), and the photovoltaic cell (6) further has a grid line (7) electrically connected to the welding strip (5), and the bus bar (4), the welding strip (5) and the grid line (7) constitute a conductive branch circuit; A side magnetic core (3) is arranged on one side of the middle magnetic core (1); The coil (2) is located at one end of the middle magnetic core (1) facing the bus bar (4) and is configured to generate a magnetic field after being energized; The side magnetic core (3) is arranged to excite an induced current in the conductive branch circuit, and the induced current at least partially offsets a current (I2) excited in the conductive branch circuit by the magnetic field generated by the coil (2); A first top magnetic core (8) is located on one side of the middle magnetic core (1) and the side magnetic core (3) and is fixedly connected to the middle magnetic core (1) and the side magnetic core (3).

2. The electromagnetic welding head of claim 1, wherein, The middle magnetic core (1) and the side magnetic core (3) are plate-shaped, and the middle magnetic core (1) and the side magnetic core (3) are arranged in parallel to each other.

3. The electromagnetic welding head of claim 1, wherein, The first top magnetic core (8) is arranged perpendicular to the middle magnetic core (1) and the side magnetic core (3).

4. The electromagnetic welding head of claim 3, wherein, The middle magnetic core (1), the side magnetic core (3) and the first top magnetic core (8) are integrally formed.

5. The electromagnetic welding head of claim 1, wherein, The middle magnetic core (1) is cylindrical, and the side magnetic core (3) is curved and sheet-shaped. The electromagnetic welding head further comprises: A second top magnetic core (9) is circular and sheet-shaped, is located on one side of the middle magnetic core (1) and the side magnetic core (3), and is fixedly connected to the middle magnetic core (1) and the side magnetic core (3).

6. The electromagnetic welding head of claim 5, wherein, The middle magnetic core (1), the side magnetic core (3) and the second top magnetic core (9) are integrally formed.

7. The electromagnetic welding head of claim 1, wherein, The side magnetic core (3) is provided with two side magnetic cores (3) located on opposite sides of the middle magnetic core (1) and spaced apart from each other.

8. The electromagnetic welding head of claim 1, wherein, The coil (2) is a Litz wire coil.

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