Friction-stir welding method and device for aluminum alloy of battery box

Abstract

The invention discloses a friction stir welding method and device for aluminum alloy of a battery box, relates to the technical field of friction stir welding, and aims to solve the problem that in the prior art, when aluminum alloy plates of the battery box are welded, dislocation is likely to occur at the joint of the two aluminum alloy plates due to the fact that no alignment mechanism is arranged. Second T-shaped limiting sliding grooves are formed in the outer sides of the middles of the upper end faces of the two clamping tables correspondingly, first trapezoidal clamps are arranged at the upper ends of the two second T-shaped limiting sliding grooves correspondingly, and a plurality of first T-shaped limiting sliding grooves are formed in the front ends and the rear ends of the upper end faces of the two clamping tables at equal intervals. A second trapezoid clamp is arranged at the upper end of each first T-shaped limiting sliding groove, the first trapezoid clamps and the second trapezoid clamps which are symmetrically distributed are arranged, the first trapezoid clamps are accurately centered in the horizontal direction through a servo motor driving screw, and the multiple sets of second trapezoid clamps achieve longitudinal synchronous clamping through a synchronous hydraulic system; alignment of welding joints is ensured, and the problem of plate dislocation is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of friction stir welding, and in particular to a method and device for friction stir welding of aluminum alloy of a battery box. Background Art

[0002] Friction stir welding is an advanced solid-phase joining technology. Its principle is to insert a high-speed rotating stirring head into the material to be welded, and use the friction heat between the shaft shoulder and the workpiece to soften the metal (below the melting point), while realizing grain reorganization under the action of mechanical stirring. During the welding process, the stirring head moves along the joint, and the metal in the thermoplastic state forms a dense weld under pressure. Compared with traditional fusion welding, FSW is smoke-free and splash-free, and can effectively avoid common defects such as cracks and pores in aluminum alloy welding. This technology is particularly suitable for the welding of light metals such as aluminum alloys and magnesium alloys. It is widely used in aerospace, new energy vehicles and other fields, especially for structural parts such as battery boxes that have high requirements for sealing and fatigue resistance.

[0003] For example, the authorization announcement number CN216632993U, a small friction stir welding device, including a base, a friction stir welding bracket, a mounting steel plate and a plurality of clamping mechanisms, wherein the friction stir welding bracket is fixedly mounted on the base, the mounting steel plate is slidably mounted on the base by a servo motor and is located below the friction stir welding arbor, a plurality of clamping mechanisms are mounted on the mounting steel plate and close to the edge of the mounting steel plate, the clamping mechanism includes a clamping block, a hydraulic cylinder and an adjustment component, the clamping block is connected to the mounting steel plate through the adjustment component, a clamping groove for mounting the workpiece to be welded is formed between the clamping block and the mounting steel plate, the hydraulic cylinder is mounted on one side of the clamping block close to the clamping groove, and the telescopic end of the hydraulic cylinder abuts against the workpiece to be welded. The utility model can realize vertical and horizontal limiting of the workpiece to be welded by setting the clamping block, the hydraulic cylinder and the adjustment component, avoid the rotation offset of the workpiece, and can meet the welding of workpieces of different widths.

[0004] However, in the above technology, only the two sides of the two products to be welded are clamped by a clamping mechanism, but no alignment mechanism is set at the front and rear ends of the two products to be welded. When welding the aluminum alloy plates of the battery box, no alignment mechanism is set, which leads to misalignment at the joints of the two aluminum alloy plates, thereby affecting the welding quality of the product. Therefore, the market urgently needs to develop a battery box aluminum alloy stir friction welding device to help people solve the existing problems. Summary of the invention

[0005] The purpose of the present invention is to provide a method and device for stir friction welding of aluminum alloy of a battery case, so as to solve the problem that in the prior art proposed in the above background technology, only the two sides of two products to be welded are clamped by a clamping mechanism, but no alignment mechanism is set at the front and back ends of the two products to be welded. When welding the aluminum alloy plates of the battery case, the two aluminum alloy plates are easily misaligned at the joints due to the lack of an alignment mechanism, thereby affecting the welding quality of the product.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a battery box aluminum alloy stir friction welding device, comprising a clamping table, wherein two clamping tables are symmetrically arranged, and the lower ends of the two clamping tables are commonly fixedly connected to a supporting base plate, and a second T-shaped limiting slide groove is arranged on the outer side of the middle part of the upper end surface of the two clamping tables, and a first trapezoidal clamp is arranged on the upper end of the two second T-shaped limiting slide grooves, and the two first trapezoidal clamps are both inverted. A first hard rubber pad is fixedly arranged on the oblique end surface of the two first trapezoidal clamps, and a plurality of first T-shaped limiting slide grooves are evenly spaced at the front and rear ends of the upper end surfaces of the two clamping tables, and a second trapezoidal clamp is arranged on the upper end of each of the first T-shaped limiting slide grooves, and the two second trapezoidal clamps are both inverted. A second hard rubber pad is fixedly arranged on the oblique end surface of the two second trapezoidal clamps.

[0007] Preferably, a screw is rotatably connected inside the second T-shaped limiting slide groove, and a driving device is fixedly connected to the upper middle ends of the outer sides of the two clamping tables. A servo motor is fixedly arranged inside the driving device, and one end of the screw passes through the inside of the clamping table and extends into the inside of the driving device and is fixedly connected to the output end of the servo motor.

[0008] Preferably, the lower ends of the two first trapezoidal clamps are fixedly connected with a T-shaped threaded slider, and the middle part of the T-shaped threaded slider is provided with an internal threaded hole.

[0009] Preferably, the T-threaded slider at the lower end of the first trapezoidal clamp is inserted into the second T-shaped limiting slide groove on the clamping table for limiting connection, and the screw rod passes through the internal threaded hole on the T-threaded slider and is threadedly connected to the T-threaded slider.

[0010] Preferably, a T-shaped limiting sliding block is fixedly connected to the lower end of the second trapezoidal clamp, and the T-shaped limiting sliding blocks at the lower end of the second trapezoidal clamp are respectively inserted into the first T-shaped limiting sliding grooves.

[0011] Preferably, the upper end surface of the clamping table and the outside of each first T-shaped limiting slide groove are fixedly connected with a fixed side plate, and the outside of each fixed side plate is fixedly connected with a first electrically-controlled hydraulic rod, and the telescopic end of the first electrically-controlled hydraulic rod passes through the middle of the fixed side plate and is fixedly connected to the outer end surface of the second trapezoidal clamp, and a synchronizer is commonly connected between every two longitudinally aligned first electrically-controlled hydraulic rods at the upper end of the clamping table.

[0012] Preferably, the upper end surface of the second trapezoidal clamp is fixedly connected to a support plate, the upper end of the support plate is fixedly connected to a second electrically-controlled hydraulic rod, and the lower telescopic end of the second electrically-controlled hydraulic rod passes through the support plate and extends out of the lower end surface of the support plate and is fixedly connected to a pressing plate.

[0013] Preferably, a C-shaped support frame is fixedly connected to the middle part of the upper end surface of the support base plate, a first linear drive guide rail is fixedly connected on both sides of the middle part of the upper end surface of the support base plate and on the inner side of the C-shaped support frame, a second linear drive guide rail is fixedly connected on both sides of the middle part of the inner upper end surface of the C-shaped support frame, and a lifting drive platform is provided at the upper ends of the two first linear drive guides and the lower ends of the two second linear drive guides.

[0014] Preferably, the two lifting drive platforms are respectively connected to the two first linear drive guide rails and the two second linear drive guide rails through linear sliders, and the lower end of the upper lifting drive platform and the upper end of the lower lifting drive platform are fixedly connected with a stir friction welding device.

[0015] A friction stir welding method comprises the following steps:

[0016] Step 1: First, place the two aluminum alloy plates to be welded horizontally on the upper end surfaces of the two clamping tables, respectively, and start the servo motors on both sides to drive the screws to rotate. The rotation of the screws drives the T-shaped threaded slider to move horizontally in the second T-shaped limit slide, thereby pushing the two first trapezoidal clamps to move toward each other. After the first hard rubber pad contacts the edge of the aluminum alloy plate, it continues to apply pressure, so that the end surfaces of the two aluminum alloy plates to be welded are in close contact and aligned. In this process, the inverted trapezoidal structure design can effectively prevent the plate from warping when it moves horizontally;

[0017] Step 2: After the two aluminum alloy plates are initially butted, the control system starts all the first electrically controlled hydraulic rods, and ensures the synchronous movement of multiple sets of second trapezoidal clamps through synchronizers. The T-shaped limit slider slides along the first T-shaped limit slide groove, so that the second hard rubber pad clamps the plate from the front and back sides. Since the second trapezoidal clamps are symmetrically distributed, their oblique clamping force will push the plate to automatically correct its position, ensuring that the weld is completely aligned along the length direction. In this stage, multi-point synchronous clamping effectively eliminates the plate misalignment problem caused by traditional unilateral clamping;

[0018] Step 3: After completing the two-dimensional positioning of the plate, the second electrically controlled hydraulic rod starts to work, driving the pressing plate to press vertically downward. The downward pressure generated by the pressing plate forms a rigid support with the clamping table surface to completely fix the aluminum alloy plate. In this step, the uniform pressure formed by multiple groups of pressing plates can prevent the plate from vibrating or thermally deforming during welding. At the same time, the elastic properties of the first hard rubber pad and the second hard rubber pad prevent the surface of the plate from being crushed;

[0019] Step 4: Use two lifting drive platforms to drive the two friction stir welding devices to rise and fall respectively, so that the friction stir welding heads of the two friction stir welding devices are pressed into the upper and lower ends of the welds of the two aluminum alloy plates at the same time, and then use the first linear drive guide and the second linear drive guide to drive the two lifting drive platforms to move along the weld direction respectively, so that the two friction stir welding devices perform friction stir welding on the upper ends of the weld respectively.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) In the present invention, by setting up symmetrically distributed first trapezoidal clamps and second trapezoidal clamps, three-dimensional precise positioning of the aluminum alloy plate is achieved. The first trapezoidal clamp is driven by a servo motor to achieve precise horizontal alignment of the screw, and multiple groups of second trapezoidal clamps are used to achieve longitudinal synchronous clamping through a synchronous hydraulic system. Combined with the inverted trapezoidal structure and hard rubber pad design, it not only ensures the perfect alignment of the welding seam, but also avoids the problem of plate misalignment caused by traditional unilateral clamping, thereby significantly improving the quality stability of the welding joint.

[0022] (2) In this invention, a double-sided synchronous welding mechanism is adopted, and the stir friction welding device arranged symmetrically above and below acts on the upper and lower ends of the weld at the same time. This design realizes the precise balance of welding heat input and effectively controls welding deformation. At the same time, the double-sided thermal-mechanical coupling effect makes the weld structure more dense and uniform, which is particularly suitable for the welding of structural parts with high sealing requirements such as battery boxes.

[0023] (3) In the present invention, the elastic clamping of the first hard rubber pad and the second hard rubber pad cooperates with the pressure plate controlled by the second electrically-controlled hydraulic rod, which not only ensures sufficient clamping force to prevent displacement during welding, but also avoids damage to the surface of the plate caused by excessive clamping force. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a front view of a battery case aluminum alloy friction stir welding device of the present invention;

[0025] Figure 2 It is a main cross-sectional view of the second T-shaped limiting slide groove of the present invention;

[0026] Figure 3 It is a side sectional view of the first T-shaped limiting slide groove of the present invention;

[0027] Figure 4 It is a side sectional view of a C-shaped support frame of the present invention;

[0028] Figure 5 It is an enlarged view of detail A of the present invention.

[0029] In the figure: 1. Clamping table; 101. Support base plate; 102. First T-type limit slide; 103. Second T-type limit slide; 104. First linear drive guide rail; 2. Screw; 201. Drive device; 202. Servo motor; 3. First trapezoidal clamp; 301. First hard rubber pad; 302. T-type threaded slider; 303. Internal threaded hole; 4. Fixed side plate; 401. First electric-controlled hydraulic rod; 5. Second trapezoidal clamp; 501. Second hard rubber pad; 502. T-type limit slide; 503. Support plate; 504. Second electric-controlled hydraulic rod; 505. Pressing sheet; 6. C-type support frame; 601. Second linear drive guide rail; 7. Lifting drive platform; 701. Linear slider; 702. Stir friction welding device. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0031] See also Figure 1-5 , an embodiment of the present invention: a battery box aluminum alloy stir friction welding device, comprising a clamping table 1, two clamping tables 1 are symmetrically arranged, the lower ends of the two clamping tables 1 are fixedly connected to a supporting bottom plate 101, the middle outer sides of the upper end surfaces of the two clamping tables 1 are each provided with a second T-shaped limiting slide groove 103, the upper ends of the two second T-shaped limiting slide grooves 103 are each provided with a first trapezoidal clamp 3, the two first trapezoidal clamps 3 are both inverted, the oblique end surfaces of the two first trapezoidal clamps 3 are each fixedly provided with a first hard rubber pad 301, the second T-shaped limiting slide groove 103 is internally rotatably connected with a screw 2, the middle upper ends of the outer sides of the two clamping tables 1 are each fixedly connected with a driving device 201, a servo motor 202 is fixedly arranged inside the driving device 201, one end of the screw 2 passes through the interior of the clamping table 1 and then extends to the interior of the driving device 201 and is connected to the servo motor 202 output The output end is fixedly connected, and the screw rod 2 is driven to rotate by the servo motor 202. The lower ends of the two first trapezoidal clamps 3 are fixedly connected with T-thread sliders 302, and the middle part of the T-thread slider 302 is provided with an internal threaded hole 303. The T-thread slider 302 at the lower end of the first trapezoidal clamp 3 is inserted into the internal limiting connection of the second T-limiting slide groove 103 on the clamping platform 1, and the screw rod 2 passes through the internal threaded hole 303 on the T-thread slider 302 and is threadedly connected with the T-thread slider 302. When the screw rod 2 rotates, it drives the T-thread slider 302 to move along the second T-limiting slide groove 103, so that the two first trapezoidal clamps 3 move relative to each other in the horizontal direction, and the two aluminum alloy plates to be welded are placed horizontally on the upper end surfaces of the two clamping platforms 1 respectively, so that when the two first trapezoidal clamps 3 move, they respectively push the two aluminum alloy plates to move relative to each other, so that the welding positions of the two aluminum alloy plates are in contact and aligned.

[0032] See also Figure 3 and Figure 5 A plurality of first T-shaped limiting sliding grooves 102 are evenly spaced at the front and rear ends of the upper end surfaces of the two clamping tables 1, and a second trapezoidal clamp 5 is arranged at the upper end of each first T-shaped limiting sliding groove 102. The two second trapezoidal clamps 5 are both inverted, and second hard rubber pads 501 are fixedly arranged on the oblique end surfaces of the two second trapezoidal clamps 5. The lower ends of the second trapezoidal clamps 5 are fixedly connected with T-shaped limiting sliders 502. The T-shaped limiting sliders 502 at the lower ends of the second trapezoidal clamps 5 are respectively inserted into the first T-shaped limiting sliding grooves 102, so that the second trapezoidal clamps 5 slide in the first T-shaped limiting sliding grooves 102 through the limiting sliders 502 to move longitudinally, and the upper end surfaces of the clamping tables 1 A fixed side plate 4 is fixedly connected to the outside of each first T-shaped limit slide groove 102, and a first electrically-controlled hydraulic rod 401 is fixedly connected to the outside of each fixed side plate 4. The telescopic end of the first electrically-controlled hydraulic rod 401 passes through the middle of the fixed side plate 4 and is fixedly connected to the outer end face of the second trapezoidal clamp 5. A synchronizer is commonly connected between every two longitudinally aligned first electrically-controlled hydraulic rods 401 on the upper end of the clamping table 1. When the welding positions of the two aluminum alloy plates are in contact and aligned, the multiple first electrically-controlled hydraulic rods 401 on the upper end of the clamping table 1 are controlled by the synchronizer to push the multiple second trapezoidal clamps 5 to clamp the front and rear ends of the two aluminum alloy plates, so that the front and rear ends of the two aluminum alloy plates are aligned.

[0033] See also Figure 3 and Figure 5 The upper end face of the second trapezoidal clamp 5 is fixedly connected to a support plate 503, and the upper end of the support plate 503 is fixedly connected to a second electrically-controlled hydraulic rod 504. The telescopic end of the lower end of the second electrically-controlled hydraulic rod 504 passes through the support plate 503 and extends out of the lower end face of the support plate 503 and is fixedly connected to a pressing plate 505. When the two aluminum alloy plates are aligned and centered, the multiple second electrically-controlled hydraulic rods 504 work to make the multiple pressing plates 505 descend and press down the upper end faces of the aluminum alloy plates, so that the aluminum alloy plates are pressed tightly against the upper end of the clamping table 1, so that the aluminum alloy plates are stably fixed on the clamping table 1.

[0034] See also Figure 2 and Figure 4A C-shaped support frame 6 is fixedly connected to the middle of the upper end surface of the support base plate 101, and a first linear drive guide rail 104 is fixedly connected to both sides of the middle of the upper end surface of the support base plate 101 and on the inner side of the C-shaped support frame 6. A second linear drive guide rail 601 is fixedly connected to both sides of the middle of the inner upper end surface of the C-shaped support frame 6. A lifting drive platform 7 is arranged on the upper ends of the two first linear drive guide rails 104 and the lower ends of the two second linear drive guide rails 601. The two lifting drive platforms 7 are respectively connected to the two first linear drive guide rails 104 and the two second linear drive guide rails 601 through linear sliders 701. Next, the lower end of the upper lifting drive platform 7 and the upper end of the lower lifting drive platform 7 are fixedly connected with a stir friction welding device 702, and the two lifting drive platforms 7 drive the two stir friction welding devices 702 to rise and fall respectively, so that the stir friction welding heads of the two stir friction welding devices 702 act on the upper and lower ends of the welds of the two aluminum alloy plates, and then the two lifting drive platforms 7 are driven to move along the weld direction by the first linear drive guide rail 104 and the second linear drive guide rail 601, so that the two stir friction welding devices 702 perform stir friction welding on the upper ends of the weld respectively.

[0035] A friction stir welding method comprises the following steps:

[0036] Step 1: First, place two aluminum alloy plates to be welded horizontally on the upper end surfaces of the two clamping tables 1 respectively, start the servo motors 202 on both sides to drive the screw 2 to rotate, and the rotation of the screw 2 drives the T-shaped threaded slider 302 to move horizontally in the second T-shaped limiting slide groove 103, thereby pushing the two first trapezoidal clamps 3 to move toward each other, and the first hard rubber pad 301 continuously applies pressure after contacting the edge of the aluminum alloy plate, so that the end surfaces of the two aluminum alloy plates to be welded are in close contact and aligned. In this process, the inverted trapezoidal structure design can effectively prevent the plate from warping when it moves horizontally;

[0037] Step 2: After the two aluminum alloy plates are initially butted, the control system starts all the first electrically controlled hydraulic rods 401, and ensures that the multiple sets of second trapezoidal clamps 5 move synchronously through the synchronizer, and the T-shaped limit slider 502 slides along the first T-shaped limit slide groove 102, so that the second hard rubber pad 501 clamps the plate from the front and rear sides. Since the second trapezoidal clamps 5 are symmetrically distributed, their oblique clamping force will push the plate to automatically correct its position, ensuring that the weld is completely aligned along the length direction. In this stage, the multi-point synchronous clamping effectively eliminates the plate misalignment problem caused by traditional unilateral clamping;

[0038] Step 3: After completing the two-dimensional positioning of the plate, the second electrically controlled hydraulic rod 504 starts to work, driving the pressing plate 505 to press vertically downward. The downward pressure generated by the pressing plate 505 forms a rigid support with the table surface of the clamping table 1 to completely fix the aluminum alloy plate. In this step, the uniform pressure formed by multiple groups of pressing plates 505 can prevent the plate from vibrating or thermally deforming during welding. At the same time, the elastic properties of the first hard rubber pad 301 and the second hard rubber pad 501 prevent the surface of the plate from being crushed;

[0039] Step 4: The two lifting drive platforms 7 are used to drive the two friction stir welding devices 702 to rise and fall respectively, so that the friction stir welding heads of the two friction stir welding devices 702 are pressed into the upper and lower ends of the welds of the two aluminum alloy plates at the same time, and then the two lifting drive platforms 7 are driven to move along the weld direction by the first linear drive guide 104 and the second linear drive guide 601 respectively, so that the two friction stir welding devices 702 perform friction stir welding on the upper ends of the weld respectively.

[0040] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A battery case aluminum alloy friction stir welding device, comprising a clamping table (1), characterized in that: Two clamping platforms (1) are symmetrically arranged, and the lower ends of the two clamping platforms (1) are fixedly connected to a supporting base plate (101), and the middle outer sides of the upper end surfaces of the two clamping platforms (1) are each provided with a second T-shaped limiting sliding groove (103), and the upper ends of the two second T-shaped limiting sliding grooves (103) are each provided with a first trapezoidal clamp (3), and the two first trapezoidal clamps (3) are both invertedly arranged, and the oblique end surfaces of the two first trapezoidal clamps (3) are each fixedly arranged with a first hard rubber pad (301), and the front and rear ends of the upper end surfaces of the two clamping platforms (1) are evenly spaced, and the upper end of each of the first T-shaped limiting sliding grooves (102) is provided with a second trapezoidal clamp (5), and the two second trapezoidal clamps (5) are both invertedly arranged, and the oblique end surfaces of the two second trapezoidal clamps (5) are each fixedly arranged with a second hard rubber pad (501).

2. A battery case aluminum alloy friction stir welding device according to claim 1, characterized in that: A screw rod (2) is rotatably connected inside the second T-shaped limiting sliding groove (103), and a driving device (201) is fixedly connected to the upper middle ends of the outer sides of the two clamping platforms (1), and a servo motor (202) is fixedly arranged inside the driving device (201), and one end of the screw rod (2) passes through the inside of the clamping platform (1) and then extends into the inside of the driving device (201) and is fixedly connected to the output end of the servo motor (202).

3. A battery case aluminum alloy friction stir welding device according to claim 2, characterized in that: The lower ends of the two first trapezoidal clamps (3) are both fixedly connected with a T-shaped threaded slider (302), and an internal threaded hole (303) is provided in the middle of the T-shaped threaded slider (302).

4. A battery case aluminum alloy friction stir welding device according to claim 3, characterized in that: The T-shaped threaded slider (302) at the lower end of the first trapezoidal clamp (3) is inserted into the second T-shaped limiting sliding groove (103) on the clamping platform (1) for internal limiting connection, and the screw rod (2) passes through the internal threaded hole (303) on the T-shaped threaded slider (302) and is threadedly connected to the T-shaped threaded slider (302).

5. The battery case aluminum alloy friction stir welding device according to claim 1, characterized in that: The lower end of the second trapezoidal clamp (5) is fixedly connected with a T-shaped limiting sliding block (502), and the T-shaped limiting sliding blocks (502) at the lower end of the second trapezoidal clamp (5) are respectively inserted into the interior of the first T-shaped limiting sliding groove (102).

6. A battery case aluminum alloy friction stir welding device according to claim 5, characterized in that: The upper end surface of the clamping platform (1) and the outer side of each first T-shaped limiting sliding groove (102) are fixedly connected to a fixed side plate (4), and the outer side of each fixed side plate (4) is fixedly connected to a first electrically controlled hydraulic rod (401). The telescopic end of the first electrically controlled hydraulic rod (401) passes through the middle of the fixed side plate (4) and is fixedly connected to the outer end surface of the second trapezoidal clamp (5). A synchronizer is commonly connected between each two longitudinally aligned first electrically controlled hydraulic rods (401) at the upper end of the clamping platform (1).

7. A battery case aluminum alloy friction stir welding device according to claim 1, characterized in that: The upper end surface of the second trapezoidal clamp (5) is fixedly connected to a support plate (503), the upper end of the support plate (503) is fixedly connected to a second electrically-controlled hydraulic rod (504), and the lower telescopic end of the second electrically-controlled hydraulic rod (504) passes through the support plate (503) and then extends out of the lower end surface of the support plate (503) and is fixedly connected to a pressing plate (505).

8. The battery case aluminum alloy friction stir welding device according to claim 1, characterized in that: A C-shaped support frame (6) is fixedly connected to the middle of the upper end surface of the support base plate (101); first linear drive guide rails (104) are fixedly connected to both sides of the middle of the upper end surface of the support base plate (101) and on the inner side of the C-shaped support frame (6); second linear drive guide rails (601) are fixedly connected to both sides of the middle of the inner upper end surface of the C-shaped support frame (6); and lifting drive platforms (7) are provided at the upper ends of the two first linear drive guide rails (104) and the lower ends of the two second linear drive guide rails (601).

9. A battery case aluminum alloy friction stir welding device according to claim 8, characterized in that: The two lifting drive platforms (7) are respectively connected to the two first linear drive guide rails (104) and the two second linear drive guide rails (601) via linear sliders (701), and the lower end of the upper lifting drive platform (7) and the upper end of the lower lifting drive platform (7) are both fixedly connected with a stir friction welding device (702).

10. A friction stir welding method, implemented based on a battery case aluminum alloy friction stir welding device according to any one of claims 1 to 9, characterized in that: The steps include: Step 1: First, two aluminum alloy plates to be welded are horizontally placed on the upper end surfaces of two clamping tables (1), and the servo motors (202) on both sides are started to drive the screw (2) to rotate. The rotation of the screw (2) drives the T-shaped threaded slider (302) to move horizontally in the second T-shaped limiting slide groove (103), thereby pushing the two first trapezoidal clamps (3) to move toward each other. After the first hard rubber pad (301) contacts the edge of the aluminum alloy plate, it continues to apply pressure, so that the end surfaces of the two aluminum alloy plates to be welded are in close contact and aligned. In this process, the inverted trapezoidal structure design can effectively prevent the plate from warping when it moves horizontally. Step 2: After the two aluminum alloy plates are initially butted, the control system starts all the first electrically controlled hydraulic rods (401), and ensures that the multiple sets of second trapezoidal clamps (5) move synchronously through the synchronizer, and the T-shaped limit slider (502) slides along the first T-shaped limit slide groove (102), so that the second hard rubber pad (501) clamps the plate from the front and rear sides. Since the second trapezoidal clamps (5) are symmetrically distributed, their oblique clamping force will push the plate to automatically correct its position, ensuring that the weld is completely aligned along the length direction. In this stage, the multi-point synchronous clamping effectively eliminates the plate misalignment problem caused by traditional unilateral clamping; Step 3: After completing the two-dimensional positioning of the plate, the second electrically controlled hydraulic rod (504) starts to work, driving the pressing plate (505) to press vertically downward. The downward pressure generated by the pressing plate (505) forms a rigid support with the table surface of the clamping table (1), and the aluminum alloy plate is completely fixed. In this step, the uniform pressure formed by the multiple groups of pressing plates (505) can prevent the plate from vibrating or thermally deforming during the welding process. At the same time, the elastic properties of the first hard rubber pad (301) and the second hard rubber pad (501) prevent the surface of the plate from being crushed; Step 4: The two lifting drive platforms (7) are used to drive the two friction stir welding devices (702) to rise and fall respectively, so that the friction stir welding heads of the two friction stir welding devices (702) are pressed into the upper and lower ends of the welds of the two aluminum alloy plates at the same time, and then the two lifting drive platforms (7) are driven to move along the weld direction by the first linear drive guide rail (104) and the second linear drive guide rail (601), so that the two friction stir welding devices (702) respectively perform friction stir welding on the upper ends of the weld.

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