Welding method for conductive wire in stacked battery structure

Abstract

A welding method for a conductive wire (3) in a stacked battery structure. The stacked battery structure comprises raw battery sheets (1), current collecting layers (2) disposed on the raw battery sheets (1), and a conductive wire (3) disposed on the current collecting layers (2). The welding method comprises: S1, providing a rotary welding apparatus (4), wherein the rotary welding apparatus (4) comprises: a heating apparatus (4-1) and / or a drum heating rod, and a rotary welding drum (4-2), and the drum heating rod is arranged inside the rotary welding drum (4-2); S2, disposing the raw battery sheets (1) provided with the current collecting layers (2) on a surface of the rotary welding drum (4-2) along the circumference thereof; S3, applying a flux material onto the conductive wire (3); S4, winding the conductive wire (3) along the circumference of the rotary welding drum (4-2) and enabling the conductive wire (3) to correspond to the current collecting layers (2) on the raw battery sheets (1); S5, starting the rotary welding drum (4-2) to enable same to rotate, and performing heating by means of the heating apparatus (4-1) and / or the drum heating rod, so that the current collecting layer (2) is connected to the conductive wire (3); and S6, after welding, cutting off the conductive wire (3), to complete the welding of the conductive wire (3) in the stacked battery structure.

Description

A welding method for conductive wires in a stacked grid battery structure Technical Field

[0001] The present invention relates to the technical field of photovoltaic cells, and in particular to a method for welding conductive wires in a stacked grid cell structure. Background Art

[0002] The conventional welding process for photovoltaic module cells is as follows: in a stringing machine, a robotic arm grabs the cell and places it on a preheated conveyor belt, a gripper grabs the conductive wire at the outlet and places it on the current collection layer corresponding to the cell, and then an external heating device heats and transfers the temperature to the cell to complete the connection between the current collection layer and the conductive wire; when the cell is transferred to the lampshade of the heating device, the infrared lamp heats and welds it, and after welding one cell in a beat, it is turned off and waits for the subsequent cell to be transferred to the lampshade before heating and welding the next cell.

[0003] This conventional beat-type welding process not only has the problem of low welding efficiency, but also has the following problems: (1) During the conventional beat-type welding process, the overall heating uniformity of the battery cell is poor, which easily leads to the phenomenon of cold solder joints in the local solder strip area of ​​the battery cell. During the heating process of the heating device, the heat dissipation temperature of the central area of ​​the lampshade is lower than that of the four corners, and the heat loss in the middle area is less and the temperature is higher, which will cause local cold solder joints or over-soldering to occur frequently during the welding process, seriously affecting the welding quality of the battery cell and causing the welding tension to fail to meet the standard requirements; (2) During the beat-type welding process, when the light of the heating device flashes, the temperature will rise sharply. During the rapid heating process, the excessive thermal shock will cause abnormal problems such as hidden cracks and fragments in the battery cell. During the beat-type welding process, the battery cell is prone to thermal expansion and cooling contraction. Excessive thermal shock will cause problems such as hidden cracks and fragments in the battery cell; (3) The conventional welding process is suitable for traditional conductive wires such as flat or round wires. After the battery cell is transferred to the position, the clamp grabs the conductive wire and puts it on the current collection layer. The conductive wire is pressed onto the current collection layer by the pressing tool, and the battery cell is welded under the conditions of pressure and temperature. However, special-shaped conductive wires such as triangular conductive wires are prone to excessive pressure in the pressure module during the pressing process of the pressing tool, which leads to problems such as hidden cracks and fragments in the battery cell. The conventional battery cell beat welding method is not suitable for welding special-shaped conductive wires, and it is difficult to control the pressure. (4) The welding speed of the conventional beat welding method is slow. In each operation cycle, each group of manipulators only transports one whole battery cell to the welding belt. In a single operation cycle, each group of wire pulling mechanisms can only complete the laying of the conductive wire of a whole battery cell. In a single operation cycle, each welding belt can only complete the transport of the process length of a whole battery cell each time it runs once. In a single operation cycle, each welding area only completes the welding of one whole battery cell and the conductive wire. At this stage, the beat welding method only completes the welding of a single whole battery cell in each operation cycle. The welding time required for a single whole battery cell is the main bottleneck restricting the improvement of the production capacity of the welding production equipment.

[0004] In summary, the current rhythmic welding of string welding machines can no longer meet the needs of rapid production, and it is urgent to develop a new welding process to meet the needs of rapid production. Summary of the Invention Technical issues Technical Solutions

[0005] The purpose of the present invention is to provide a welding method for conductive wires in a stacked grid battery structure to address the problems existing in the existing string welding machine's tactile welding conductive wire process, thereby effectively solving many problems faced by the existing process.

[0006] The present invention is achieved through the following technical solutions:

[0007] Provided is a method for welding conductive wires in a stacked grid battery structure, the stacked grid battery structure comprising: an original battery cell, a current collection layer disposed on the original battery cell, and a conductive wire disposed on the current collection layer; the current collection layer is used to collect current generated in the battery cell and direct the current to the conductive wire for transmission through the conductive wire;

[0008] The welding method comprises the following steps:

[0009] S1. Provide a rotary welding device;

[0010] Wherein: the rotary welding device comprises: a heating device and / or a roller heating rod, and a rotary welding cylinder; the roller heating rod is arranged inside the rotary welding cylinder;

[0011] S2. Fixing a plurality of the original battery sheets provided with the current collection layer on the surface of the rotary welding cylinder along the circumference thereof;

[0012] S3, applying flux material (the flux material is a conductive material) on the conductive wire;

[0013] S4, winding the conductive wire on the rotary welding cylinder along the circumference thereof, and making the conductive wire correspond to the current collection layer on the original battery sheet;

[0014] S5, starting the rotary welding cylinder to rotate, and then heating it through the heating device and / or the roller heating rod to connect the current collecting layer and the conductive wire together;

[0015] S6. After welding, the conductive wire is cut off to complete the welding of the conductive wires in the stacked grid battery structure.

[0016] Specifically, the present invention is designed to provide a method for welding conductive wires in a stacked-grid battery structure: it is suitable for welding conductive wires in stacked-grid batteries, and the process of attaching original battery cells to the surface of a cylindrical rotating welding cylinder and then winding the conductive wire is completed by welding. After the winding (conductive wire) on the rotating welding cylinder is completed, the rotating welding cylinder is placed in a uniform rotation mode, and during the rotation, an external heating device is turned on for heating, so that several original battery cells transfer heat evenly to each original battery cell while rotating, and through the tension of the wound conductive wire, the conductive wire welding of multiple original battery cells is completed at one time, greatly improving the welding efficiency.

[0017] The welding method adopted by the present invention is a continuous rotation welding process. The process of the present invention can make the overall uniformity of the temperature applied to the original battery cell high. During the rotation process, since the rotating welding cylinder is in a uniform rotation motion, the temperature in the circumferential direction of the rotating welding cylinder can always maintain the same temperature. The axial temperature of the original battery cell is mainly determined by the length of the infrared lamp tube and the heat loss on both sides; in the beat-type welding process, the positions of each point of the original battery cell are fixed, and the axial and radial temperature differences of the original battery cell need to be controlled. The temperature differences at each point can easily lead to quality problems such as local cold welding and over-welding in the battery cell; and the uniform rotation welding method designed in this application can effectively solve the problem of poor temperature uniformity in the welding process and effectively improve the welding quality.

[0018] Preferably, the heating device is an infrared heating device.

[0019] Furthermore, a method for welding conductive wires in a stacked grid battery structure is provided: the cross section of the conductive wires is triangular.

[0020] The continuous rotation welding process designed in the present invention is suitable for welding special-shaped conductive wires (such as triangular conductive wires). In the stacked grid battery structure, triangular conductive wires are usually selected to connect with the current collection layer (gate line). Since the top angle of the triangular conductive wire is a sharp angle, during the conventional beat welding process, the pressure exerted by the block tooling on the conductive wire can easily cause hidden cracks and fragments in the battery cell. In the welding process provided by the present invention, the fitting force between the conductive wire and the current collection layer is controlled by the winding tension, and then combined with uniform rotation welding, thereby achieving the welding requirements of the triangular conductive wire and the current collection layer. The uniform rotation welding process provided by the present invention is more suitable for welding special-shaped conductive wires in the stacked grid battery structure.

[0021] The welding method provided by the present invention is suitable for welding special-shaped conductive wires and original battery sheets, and is suitable for welding stacked grid battery structures.

[0022] Furthermore, a method for welding conductive wires in a stacked grid battery structure is provided: the heating device described in step S1 is an infrared heating device or a hot air heating device.

[0023] Furthermore, a method for welding conductive wires in a stacked grid battery structure: Step S2, before fixing the original battery cell on the surface of the rotary welding cylinder, preheat the rotary welding cylinder.

[0024] The welding method of the present invention: during the continuous rotary welding process, the temperature transfer speed is slower. After the rotary welding tube is preheated, the original battery cell loses heat more slowly during the welding process. The thermal expansion and cooling of the overall welding process have less impact on the battery cell, and the probability of the battery cell having problems such as hidden cracks and fragments is also smaller.

[0025] Furthermore, a method for welding conductive wires in a stacked grid battery structure: Step S2, a plurality of original battery sheets arranged along the circumference of the rotating welding cylinder are arranged in a straight line.

[0026] This makes it easier for the conductive wire to correspond to the current collection layer of the original battery cell after winding.

[0027] Furthermore, a method for welding conductive wires in a stacked grid battery structure: Step S2, adsorption holes are provided on the surface of the rotary welding cylinder; the interior of the rotary welding cylinder is evacuated, and the battery cell is adsorbed and fixed on the surface of the rotary welding cylinder using the adsorption holes.

[0028] Furthermore, a method for welding conductive wires in a stacked grid battery structure: Step S2, a number of original battery cells provided with the current collection layer and the inter-cell connecting strips are arranged on the surface of the rotating welding cylinder in an alternating manner of original battery cells and inter-cell connecting strips, along the circumference of the rotating welding cylinder in a manner that the two ends of the original battery cells are flush with the two ends of the inter-cell connecting strips.

[0029] There are inter-cell connecting strips between the original battery cells, and the conductive wires are arranged on the inter-cell connecting strips. This is to adapt to different subsequent battery cell series connection methods.

[0030] Furthermore, a method for welding the conductive wire in a stacked grid battery structure is provided: the welding point between the conductive wire and the inter-sheet connecting strip is reinforced by methods including but not limited to laser, hot pressing welding or electromagnetic welding, and the conductive wire is cut off after the welding is completed.

[0031] Furthermore, a method for welding conductive wires in a stacked grid battery structure is provided: the inter-sheet connecting strips are fixed to the surface of the rotating welding cylinder by adsorption through adsorption holes.

[0032] Furthermore, a method for welding a conductive wire in a stacked grid battery structure: Step S3, passing the conductive wire through a slot containing the flux material so that the flux material is obtained on the conductive wire.

[0033] Conventional pulsed cell welding processes can only weld one whole cell per cycle, while continuous rotation welding can weld multiple cells per cycle, significantly improving welding efficiency. Continuous rotation welding improves temperature uniformity throughout the welding process, reduces the likelihood of cold welds, and enhances weld quality. Continuous rotation welding effectively avoids problems such as cell expansion, cracking, and fragmentation caused by rapid temperature rise and fall during conventional pulsed cell welding.

[0034] In the present invention, the current collection layer refers to a conductive layer that forms good contact with the battery surface to collect the current generated by the battery. The conductive layer is distributed in a graphical form on the positive electrode and / or negative electrode of the battery, respectively referred to as the positive electrode current collection layer and the negative electrode current collection layer.

[0035] Conductive wire refers to a wire that forms good contact with the current collection layer to conduct current longitudinally and laterally. The wire is distributed in a graphical form at the positive and / or negative electrodes of the battery, and is called the positive electrode conductive wire and the negative electrode conductive wire respectively.

[0036] The stacked grid battery structure refers to a structure in which the current collection layer is covered with a conductive wire and the two form good contact.

[0037] The original cell refers to: the original cell used for grid stacking welding; grid stacking welding refers to the welding process for forming a grid stacking structure.

[0038] Inter-cell connecting strips are conductive strips used to connect the positive conductive wire of one battery to the negative conductive wire of another battery. Beneficial effects

[0039] Beneficial effects of the present invention:

[0040] The welding method provided by the present invention effectively solves the problem of low welding efficiency in the original battery cell and conductive wire welding process. The welding method of the present invention also solves the problem of poor temperature uniformity and localized cold solder joints that are easily caused during conventional battery cell tactile welding. The welding method of the present invention also solves the problem of excessive thermal shock to the battery cell, resulting in hidden cracks, fragments, and other abnormalities caused by rapid temperature rise and fall during conventional tactile welding processes. The method of the present invention also solves the problem of difficulty in matching battery cells with special-shaped conductive wires during conventional tactile welding processes.

[0041] The welding method of the present invention can ensure that the overall heating uniformity of the battery cell is higher during the welding process, thereby improving the welding quality. In the welding process of the present invention, the temperature difference between heating and cooling is small, which can effectively avoid the problems of battery cell expansion, hidden cracks or fragments caused by rapid heating and cooling in the conventional battery cell rhythmic welding process. The welding method of the present invention can effectively solve the problem that the conventional battery cell welding process can only complete the welding of one whole battery cell in each operation cycle, and the welding efficiency is low; the method of the present invention is a continuous rotation welding process, which can realize the simultaneous welding of multiple battery cells in each operation cycle; the method of the present invention can not only ensure the higher welding quality of the original battery cell and the conductive wire, but also greatly improve the welding efficiency, which is a significant improvement. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0043] FIG1 is a schematic structural diagram of the present stacked grid battery;

[0044] FIG2 is a schematic structural diagram of a rotary welding device;

[0045] FIG3 is a schematic diagram of the operation of the welding method of the present invention;

[0046] FIG4 is a schematic diagram of the operation of the welding method of Example 5;

[0047] FIG5 is a schematic structural diagram of a battery unit in Example 5;

[0048] FIG6 is a schematic diagram of the operation of a conventional tactile welding process.

[0049] Markings in the figure: 1 original battery cell, 2 current collection layer, 3 conductive wire, 4 rotary welding device, 5 conveyor belt, 6 inter-cell connecting strip, 7 battery unit, 4-1 heating device, 4-2 rotary welding cylinder. Modes for Carrying Out the Invention

[0050] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0051] In the description of the present invention, it should be understood that the terms "upper", "lower", "left", "right", "top", "bottom", etc., indicating directions or positional relationships, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific direction, be constructed and operate in a specific direction, and therefore should not be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Moreover, the terms "first", "second", etc. are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. Example 1

[0052] A method for welding conductive wires in a stacked grid battery structure is provided. The stacked grid battery structure is shown in FIG1 and includes: an original battery cell 1, a current collection layer 2 disposed on the original battery cell 1, and a conductive wire 3 (specifically, a triangular conductive wire 3) disposed on the current collection layer 2; the current collection layer is used to collect current generated in the original battery cell 1 and direct the current to the conductive wire 3 for transmission through the conductive wire 3;

[0053] The welding method comprises the following steps:

[0054] S1, providing a rotary welding device 4;

[0055] Wherein: the rotary welding device 4 comprises: an infrared heating device 4-1 and a rotary welding cylinder 4-2; the surface of the rotary welding cylinder 4-2 is provided with a plurality of adsorption holes;

[0056] S2. Preheat the rotary welding cylinder 4-2 using the infrared heating device 4-1 to prevent problems such as hidden cracks and fragments in the battery cells during subsequent processes; then, fix a plurality of the original battery cells 1 provided with the current collection layer 2 on the surface of the rotary welding cylinder 4-2 along its circumference (specifically, the interior of the rotary welding cylinder 4-2 is evacuated and the original battery cells 1 are fixed to the surface of the rotary welding cylinder 4-2 by adsorption using a plurality of adsorption holes provided therein); Note: When adsorbing and fixing a plurality of original battery cells 1 on the surface of the rotary welding cylinder 4-2, the original battery cells 1 are arranged in a line along its circumference;

[0057] S3, passing the conductive wire 3 through a slot filled with flux material, so that the flux material adheres to the surface of the conductive wire 3;

[0058] S4, winding the conductive wire 3 on the rotary welding cylinder 4-2 along its circumference, and making the conductive wire 3 correspond to the current collection layer 2 on the original battery cell 1; using the tension of the winding as the pressure between the conductive wire 3 and the original battery cell 1 during welding;

[0059] S5. Start the rotary welding cylinder 4-2 to rotate continuously (rotate at a constant speed). At this time, the multiple original battery cells 1 fixed on the rotary welding cylinder 4-2 rotate together; then, the infrared heating device 4-1 heats the current collection layer 2 and the conductive wire 3.

[0060] S6. After welding, the conductive wires 3 connecting the original battery cells 1 are cut off, thus completing the welding of the conductive wires 3 in the stacked grid battery structure.

[0061] The structure of the rotary welding device 4 in the above embodiment 1 is shown in FIG2 . The welding method in the above embodiment 1 is a continuous rotary welding method, and its process flow is shown in FIG3 .

[0062] The welding method provided by the present invention: continuous rotary welding can simultaneously weld multiple original battery cells 1 in each operating cycle. When multiple original battery cells 1 are arranged in order on the circumference of the cylindrical rotary welding cylinder 4-2 and continuously rotate, the external infrared heating device 4-1 continuously heats the multiple original battery cells 1 at the same time. The number of original battery cells welded in each cycle is the total number of original battery cells placed on the surface of the rotary welding cylinder 4-2. After each working cycle is completed, batch welding of multiple original battery cells and conductive wires can be achieved at one time, greatly improving welding efficiency. In the above-mentioned uniform speed rotary welding method, the number of original battery cells that need to be welded in each working cycle can be increased accordingly according to the size of the rotary welding cylinder 4-2, so as to further increase the number of original battery cells welded at one time, improve the welding speed of the original battery cells, improve welding efficiency, and improve production efficiency. Example 2

[0063] The difference between Example 2 and Example 1 is that a hot air heating device 4-1 is used for heating; the rest is the same as Example 1. Example 3

[0064] The difference between Example 3 and Example 1 is that Example 3 eliminates the external heating device 4-1 and instead implements the heating function by installing a roller heating rod inside the rotary welding cylinder 4-2. The rest of the embodiment is the same as Example 1. The roller heating rod in Example 3 functions as the heating device 4-1. Example 4

[0065] The difference between Example 4 and Example 1 is that in Example 4, an external heating device 4-1 is provided, and a roller heating rod is provided inside the rotary welding cylinder 4-2 to achieve a dual heating function; the rest is the same as Example 1. Example 5

[0066] A method for welding conductive wires in a stacked grid battery structure is provided. The stacked grid battery structure is shown in FIG1 and includes: an original battery cell 1, a current collection layer 2 disposed on the original battery cell 1, and a conductive wire 3 disposed on the current collection layer 2; the current collection layer is used to collect current generated in the original battery cell 1 and conduct the current to the conductive wire 3 for transmission through the conductive wire 3;

[0067] The welding method includes the following steps:

[0068] S1, providing a rotary welding device 4;

[0069] Wherein: the rotary welding device 4 comprises: an infrared heating device 4-1 and a rotary welding cylinder 4-2; the surface of the rotary welding cylinder 4-2 is provided with a plurality of adsorption holes;

[0070] S2. Preheat the rotary welding cylinder 4-2 by the infrared heating device 4-1 to avoid problems such as hidden cracks and fragments in the battery cells during subsequent processes;

[0071] Then, a number of original battery cells 1 provided with current collection layers 2 and inter-cell connecting strips 6 (generally of the same length as the original battery cells 1) are arranged on the surface of the rotary welding cylinder 4-2 in an alternating manner, with the original battery cells and inter-cell connecting strips arranged in sequence, so that the ends of the original battery cells 1 and the inter-cell connecting strips 6 are flush with each other (as shown in FIG4 ). Specifically, the original battery cells 1 and the inter-cell connecting strips 6 are fixed to the surface of the rotary welding cylinder 4-2 by adsorption holes.

[0072] S3, passing the conductive wire 3 through a slot filled with flux material, so that the flux material adheres to the surface of the conductive wire 3;

[0073] S4. Wind the conductive wire 3 around the rotating welding cylinder 4-2 along its circumference, and make the conductive wire 3 correspond to the current collecting layer 2 on the original battery cell 1; use the tension of the winding (conductive wire 3) as the pressure between the conductive wire 3 and the battery cell 1 during welding;

[0074] S5. Start the rotary welding cylinder 4-2 and make it rotate continuously. At this time, the multiple original battery cells 1 fixed on the rotary welding cylinder 4-2 rotate together; then, the infrared heating device 4-1 heats the current collecting layer 2, the inter-cell connecting strip 6 and the conductive wire 3 together;

[0075] S6. After welding, the welding point between the conductive wire 3 and the inter-sheet connecting strip 6 can be reinforced by laser, hot pressing welding or electromagnetic welding, and then the conductive wire 3 connecting the previous inter-sheet connecting strip 6 and the next original battery cell 1 is cut to form a plurality of battery cells 7 (as shown in FIG5 , each battery cell 7 includes an original battery cell 1 and an inter-sheet connecting strip 6, and the original battery cell 1 is connected to the inter-sheet connecting strip 6 through the conductive wire 3 to form a battery cell 7), completing the welding of the conductive wire 3 in the stacked grid battery structure. Comparative Example 1

[0076] A method for welding conductive wires in an existing stacked grid battery structure is provided. The method is a tactile welding method, and its process flow is shown in FIG6 . The method comprises:

[0077] First, the conveyor belt 5 is preheated by the infrared heating device 4-1; then, an external robotic arm is used to grab the original battery cell 1 provided with the current collection layer 2 and place the original battery cell 1 on the preheated conveyor belt 5;

[0078] The original cell 1 is conveyed to the infrared heating device 4-1 by the conveyor belt 5, and the conveying is stopped; then the conductive wire 3 (this conductive wire is generally flat or cylindrical) with the soldering material adhered to the surface is grasped by the clamping claw and placed on the current collection layer 2; then the conductive wire 3 is pressed onto the current collection layer 2 by the external pressing tool;

[0079] The conductive wire 3 is heated by the infrared heating device 4-1 to connect the current collection layer 2 together; after completing the welding of an original battery cell 1, the welded battery cell is continued to be conveyed downstream through the conveyor belt 5. At this time, the original battery cell 1 is continued to be grabbed by the robotic arm and placed on the conveyor belt 5, and the above process steps are repeated to carry out the welding process of the conductive wire 3 and the original battery cell 1.

[0080] The welding method provided in the above comparative example 1 is a rhythmic welding method, which has the problem of low welding efficiency; in this rhythmic welding method, in each operation cycle, each group of robots only carries one whole battery cell to the conveyor belt 5, and in a single operation cycle, the clamp can only complete the conductive wire laying work of a whole battery cell (that is, the docking work of the conductive wire and the current collection layer). In a single operation cycle, each time the conveyor belt 5 runs once, it can only complete the transportation action of the process length of a whole battery cell. In a single operation cycle, only the welding work of a whole battery cell and the conductive wire is completed, and its work efficiency is very low.

[0081] The welding method of Example 1 has the following problems: the overall heating uniformity of the battery cell is poor, and the phenomenon of cold welding is prone to occur, which seriously affects the welding quality of the battery cell and causes the welding tension to fail to meet the standard requirements. The welding method of Example 1 also has the following problems: when the infrared heating device 4-1 is heating, the temperature will rise sharply. During the rapid heating process, the excessive thermal shock will cause abnormal problems such as hidden cracks and fragments in the battery cell. The welding method of Example 1 also has the problem of a narrow range of applicable conductive wires. This welding method is only applicable to conventional flat or round conductive wires, and this welding method requires the use of a block tool to press the conductive wire and the current collection layer. However, the block tool can easily exert excessive pressure on the battery cell, resulting in hidden cracks and fragments in the battery cell.

[0082] The welding method provided by the present invention is applicable to a wider range of conductive wires to be welded, and can be applied to welding special-shaped conductive wires and battery cells.

[0083] In the welding method provided by the present invention, the tension generated by the winding wire (conductive wire) is used as the pressure between the conductive wire and the battery cell during welding, and the pressure is uniform and controllable. This avoids the process of using a pressurizing tool to press the conductive wire and the battery cell in the traditional method. Since the method of the present invention omits the process of pressurizing the battery cell with an external pressurizing tool, it also avoids the problem of hidden cracks and fragments of the battery cell caused by excessive pressure.

[0084] The above preferred embodiments of the present invention are only used to explain the present invention and are not used to limit the present invention. Any obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for welding conductive wires in a stacked grid battery structure, characterized in that: The stacked grid battery structure comprises: an original battery cell (1), a current collection layer (2) arranged on the original battery cell (1), and a conductive wire (3) arranged on the current collection layer (2); The welding method comprises the following steps: S1. Providing a rotary welding device (4); Wherein: the rotary welding device (4) comprises: a heating device (4-1) and / or a roller heating rod, and a rotary welding cylinder (4-2); the roller heating rod is arranged inside the rotary welding cylinder (4-2); S2, fixing a plurality of the original battery sheets (1) provided with the current collection layer (2) on the surface of the rotating welding cylinder (4-2) along the circumference thereof; S3, applying flux material on the conductive wire (3); S4, winding the conductive wire (3) around the rotary welding cylinder (4-2) along its circumferential direction, and making the conductive wire (3) correspond to the current collecting layer (2) on the original battery sheet (1); S5, starting the rotary welding cylinder (4-2) to rotate it, and then heating it, so that the current collecting layer (2) and the conductive wire (3) are connected together; S6. After welding, the conductive wire (3) is cut off to complete the welding of the conductive wires in the stacked grid battery structure.

2. The method for welding conductive wires in a stacked grid battery structure according to claim 1, characterized in that: The cross section of the conductive wire (3) is triangular.

3. The method for welding conductive wires in a stacked grid battery structure according to claim 1, characterized in that: The heating device (4-1) described in step S1 is an infrared heating device or a hot air heating device.

4. The method for welding conductive wires in a stacked grid battery structure according to claim 1, characterized in that: Step S2: before the original battery cell (1) is fixedly arranged on the surface of the rotary welding cylinder (4-2), the rotary welding cylinder (4-2) is preheated.

5. The method for welding conductive wires in a stacked grid battery structure according to claim 1, characterized in that: Step S2: a plurality of original battery sheets (1) arranged along the circumference of the rotary welding cylinder (4-2) are arranged in a straight line.

6. The method for welding conductive wires in a stacked grid battery structure according to claim 1, characterized in that: Step S2, a plurality of adsorption holes are provided on the surface of the rotary welding cylinder (4-2); The interior of the rotary welding cylinder (4-2) is evacuated, and the original battery sheet (1) is adsorbed and fixed on the surface of the rotary welding cylinder (4-2) through the adsorption holes.

7. The method for welding conductive wires in a stacked grid battery structure according to claim 1, characterized in that: Step S2: arranging a plurality of original battery cells (1) provided with the current collection layer (2) and inter-cell connecting strips (6) on the surface of the rotating welding cylinder (4-2) in an alternating manner of original battery cells and inter-cell connecting strips, flush with each other along the circumference of the rotating welding cylinder (4-2).

8. The method for welding conductive wires in a stacked grid battery structure according to claim 7, characterized in that: The welding point between the conductive wire (3) and the inter-sheet connecting strip (6) is reinforced by using methods including but not limited to laser, hot pressing welding or electromagnetic welding, and the conductive wire (3) is cut off after the welding is completed.

9. The method for welding conductive wires in a stacked grid battery structure according to claim 7, characterized in that: The inter-sheet connecting strip (6) is fixed to the surface of the rotary welding cylinder (4-2) by adsorption through adsorption holes.

10. The method for welding conductive wires in a stacked grid battery structure according to claim 1, characterized in that: Step S3: passing the conductive wire (3) through a slot containing the soldering material, so that the soldering material is attached to the conductive wire (3).

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