A gas shielded welding tooling for fuel cell metal bipolar plates and its process method

Abstract

The present invention provides a gas shielded welding tooling for fuel cell metal bipolar plates and its process method, which includes an upper fixing plate, a lower fixing plate, a protective gas chamber, an air inlet, an external clamping structure, an internal clamping structure, positioning pins, metal plates and quick plugs. The upper fixing plate and the lower fixing plate form a tooling skeleton support mechanism, the protective gas chamber and the air inlet form a tooling protection mechanism, and the external clamping structure, the internal clamping structure and the positioning structure form a tooling fastening mechanism. For the gas shielded welding tooling proposed by the present invention, the metal plates are accurately positioned with the upper and lower fixing plates of the tooling through the positioning structure. The tooling is provided with a protective gas chamber matching the welding area of the plates, and an external clamping structure for clamping the fixing plates to keep their positions stable, which is convenient for connecting the protective gas cylinder to the tooling, can improve the oxidation problem and thermal deformation problem of the plates without affecting the welding efficiency, and improve the welding quality of the metal plates.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and particularly to a shielding gas welding tooling for fuel cell metal bipolar plates and its process method. Background Art

[0002] A fuel cell generates electrons through a chemical reaction of hydrogen and oxygen fuels and then generates electric energy. Its key components include metal bipolar plates, membrane electrodes, etc. Since the final product of the hydrogen-oxygen reaction is water, fuel cell technology can achieve pollution-free and zero-emission, and has become a new energy technology widely concerned internationally. At the same time, metal bipolar plates are gradually replacing graphite plates due to their advantages such as small volume and light weight.

[0003] Currently, the preparation of metal bipolar plates by welding is a relatively common process method. Since the surface of the welding area of the metal plate is exposed to the air during the welding process, oxidation will occur on the plate surface, affecting the surface quality of the welding. At the same time, due to the input of heat during the welding process, thermal deformation will occur on the surface of the plate welding area, affecting the subsequent assembly and use of the stack. In view of the processing problems brought by the welding process, it is particularly important to design a shielding gas welding tooling.

[0004] The shielding gas welding tooling has the advantages of simple structure, convenient processing, a wide range of shielding gases used. After the gas is introduced into the tooling, it can blow out the internal air, provide cooling for the plate welding area, and can effectively solve the oxidation problem and thermal deformation problem of the metal bipolar plate during the welding process. At the same time, the shielding gas welding tooling is designed with a positioning structure and a pressing structure to ensure that the plates can maintain their relative positions unchanged during the welding process, and the mutual contact between the plates can be closer, improving the welding quality.

[0005] In the prior art, the invention patent with the application number CN201810812190 discloses a welding fixture scheme for fuel cell metal bipolar plates. In this scheme, the plates are placed on a profiling plate and the plates are adsorbed by an electromagnet to make the plates in close contact. The structure of this tooling device is relatively complex, the cost is relatively high, and the electromagnets are asymmetrically distributed. The plates are easily deformed by the suction force on one side, and the magnitude of the adsorption force needs to be checked regularly, and it cannot protect the plates from thermal deformation during the welding process. Clamping structures are designed on both sides of the upper and lower fixing plates of the shielding gas welding tooling to ensure the balance of the force on the plates. The clamping force can meet the requirement that the plates can be in close contact. The shape of the clamping structure only needs to be consistent with the welding area, which is convenient for processing. The introduction of the shielding gas can not only reduce the oxidation of the plate surface, but also provide cooling, reduce the thermal deformation of the plates, and improve the welding quality. Summary of the Invention

[0006] The purpose of the present invention is to provide a shielding gas welding tooling for fuel cell metal bipolar plates and its process method.

[0007] To achieve the above object, the technical solution of the present invention is as follows:

[0008] A gas shielded welding tooling for fuel cell metal bipolar plates, characterized in that it includes an upper fixing plate, a metal plate and a lower fixing plate which are arranged in sequence from top to bottom. The upper fixing plate, the metal plate and the lower fixing plate have the same length in the left-right direction and the same width in the front-back direction. Two protective gas cavities are provided on the left and right sides of the upper fixing plate. The protective gas cavities penetrate through the upper and lower ends of the upper fixing plate. The protective gas cavities are symmetrically arranged left and right. A plurality of air inlets are provided on the outer edges of the left and right ends of the upper fixing plate. The air inlets are open at the upper end of the upper fixing plate. The lower end of the air inlet is communicated with the protective gas cavity through a trachea. Each air inlet is correspondingly provided with a quick plug. The quick plug is installed on the upper part of the air inlet. The quick plug is used to connect the tooling with a protective gas cylinder. The four corners of the upper fixing plate, the metal plate and the lower fixing plate are connected by positioning pins. The upper fixing plate, the metal plate and the lower fixing plate are fastened by positioning pins and an external clamping structure. Internal clamping structures are provided on the left and right sides of the lower end of the upper fixing plate and the left and right sides of the upper end of the lower fixing plate and are matched with each other. Hollow parts are provided on the left and right sides of the metal plate. The internal clamping structures pass through the hollow parts.

[0009] Further, the external clamping structure is an elbow clamp type structure.

[0010] Further, the protective gas cavity includes a first transverse groove, a second transverse groove, a first inclined groove, a second inclined groove and a longitudinal groove. The first transverse groove and the second transverse groove are arranged in sequence front and back and are parallel to each other. The outer end of the first transverse groove is connected to one end of the first inclined groove. The outer end of the second transverse groove is connected to one end of the second inclined groove. The first inclined groove and the second inclined groove extend obliquely outward from one end to the other end. The first inclined groove and the second inclined groove extend obliquely and symmetrically towards each other. The other ends of the first inclined groove and the second inclined groove are connected by a longitudinal groove.

[0011] Further, the protective gas cavity further includes a first branch groove and a second branch groove which are arranged in sequence front and back. One ends of the first branch groove and the second branch groove are communicated with the inner side of the longitudinal groove. The first branch groove is inclined backward from one end to the other end. The second branch groove is inclined forward from one end to the other end.

[0012] Further, the air inlet is a circular opening.

[0013] Further, the internal clamping structure is a plurality of rows of parallel reinforcing ribs or ridges which are arranged in a staggered manner up and down, so that the concave and convex parts between the upper fixing plate and the lower fixing plate are embedded in each other.

[0014] Further, a sealing ring is provided on the outer side of the internal clamping structure. The sealing ring is fixed to the upper end of the lower fixing plate and is arranged in a square shape along the outer side of the lower fixing plate.

[0015] Further, it further includes a cover plate located at the upper end of the upper fixing plate. The left and right sides of the cover plate cover and protect the gas cavity, and the length of the cover plate is shorter than that of the upper fixing plate.

[0016] Further, a plurality of exhaust ports are provided on the front and rear sides of the upper fixing plate and the lower fixing plate, and the exhaust ports are communicated with the protection gas cavity.

[0017] A process method using the above-mentioned tooling is characterized by including the following steps:

[0018] (1) Select a suitable welding tooling according to the metal bipolar plate type and the distribution of the welding area;

[0019] (2) Place the lower fixing plate of the tooling on the working table of the welding equipment, place the metal plate flat on the upper surface of the lower fixing plate, and use the internal clamping structure to cooperate with the hollowing to complete the positioning;

[0020] (3) After completing the preliminary placement and positioning of the metal plate, place the upper fixing plate on the upper surface of the metal plate. The upper fixing plate and the lower fixing plate are positioned by positioning pins, and the air inlet of the tooling is connected to the protection gas cylinder pipeline;

[0021] (4) Use the external clamping structure to clamp the upper fixing plate, the metal plate and the lower fixing plate, operate the welding equipment for welding, and introduce a suitable amount of protection gas during the welding process to protect the surface of the metal plate and provide cooling;

[0022] (5) After completing the welding process of the metal plate, close the supply of the protection gas, open the external clamping structure and slowly lift the upper fixing plate, and take out the metal plate to weld the next pair of plates.

[0023] For the gas protection gas welding tooling proposed by the present invention, the metal plate is accurately positioned with the upper and lower fixing plates of the tooling through the positioning structure. The tooling includes a protection gas cavity matching the welding area of the plate, and its external is designed with a clamping structure for clamping the fixing plate to keep its position stable. The internal is designed with a clamping structure having the same shape as the welding path to ensure that the plate can maintain close contact and avoid false welding. In addition, the tooling is designed with an air inlet to facilitate the connection between the protection gas cylinder and the tooling. This process method can greatly improve the problems of plate oxidation and thermal deformation and improve the welding quality of the metal plate without affecting the welding efficiency. Description of the Drawings

[0024] Figure 1 It is a schematic overall layout diagram of the gas protection gas welding tooling in Embodiment 1 of the present invention;

[0025] Figure 2 Schematic diagram of the layout of the skeleton support mechanism in Embodiment 1 of the present invention;

[0026] Figure 3 Schematic diagram of the layout of the protection mechanism in Embodiment 1 of the present invention;

[0027] Figure 4 Schematic diagram of the layout of the fastening mechanism in Embodiment 1 of the present invention;

[0028] Figure 5 Schematic diagram of the layout of the air intake mechanism in Embodiment 1 of the present invention;

[0029] Figure 6 Schematic diagram of the overall layout of the gas shielded arc welding tooling for the metal bipolar plate of the fuel cell in Embodiment 2 of the present invention.

[0030] Reference numerals:

[0031] 1 upper fixing plate, 2 lower fixing plate, 3 shielding gas chamber, 4 air inlet, 5 external clamping structure,

[0032] 6 internal clamping structure, 7 positioning pin, 8 metal plate, 9 quick plug, 10 limiting block,

[0033] 11 exhaust port, 12 sealing ring, 13 cover plate, 14 limiting groove, 15 hollowing;

[0034] 31 first transverse groove, 32 first inclined groove, 33 longitudinal groove, 34 second inclined groove, 35 second transverse groove,

[0035] 36 first branch groove, 37 second branch groove. Detailed implementation manners

[0036] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0037] The present invention discloses a gas shielded arc welding tooling for protecting a metal bipolar plate of a fuel cell, characterized in that, as Figure 1As shown in the figure, it includes an upper fixing plate 1, a metal electrode plate 8, and a lower fixing plate 2 arranged in sequence from top to bottom. The upper fixing plate 1, the metal electrode plate 8, and the lower fixing plate 2 have the same length in the left-right direction and the same width in the front-back direction. Two protective gas chambers 3 are provided on the left and right sides of the upper fixing plate 1. The protective gas chambers 3 penetrate through the upper and lower ends of the upper fixing plate 1. The protective gas chambers 3 are symmetrically arranged left and right. A number of air inlets 4 are provided on the outer edges of the left and right ends of the upper fixing plate 1. The air inlets 4 are open at the upper end of the upper fixing plate 1. The lower end of the air inlet 4 is connected to the protective gas chamber 3 through a trachea. The air inlets 4 can adopt various air intake forms, including but not limited to inlet shapes such as circular, square, and triangular. The connection methods include but not limited to quick-insert connection, threaded connection at both ends, and clamp connection. Specifically, in implementation, the air inlet 4 is preferably a quick-insert circular port.

[0038] As Figure 1 and Figure 2 shown in the figure, each air inlet 4 is correspondingly provided with a quick plug 9. The quick plug 9 is installed at the upper part of the air inlet 4. The quick plug 9 is used to connect the tooling to the protective gas cylinder. The four corners of the upper fixing plate 1, the metal electrode plate 8, and the lower fixing plate 2 are connected by positioning pins 7. The upper fixing plate 1, the metal electrode plate 8, and the lower fixing plate 2 are fastened by positioning pins 7 and an external clamping structure 5. Specifically, in implementation, the fixing method between the upper fixing plate 1 and the lower fixing plate 2 can be adjusted. The positioning methods include but not limited to positioning by positioning pins 7, limit positioning, and positioning by cooperation of concave-convex structures, etc. The positioning positions can be selected as diagonal positioning, four-corner positioning, side positioning, etc.

[0039] The external clamping structure 5 is used to clamp the upper and lower fixing plates 2. The clamping methods include but not limited to elbow clamp type, pneumatic type, hydraulic type, electric type, bolt fastening type, external object pressing type, etc. The clamping positions include but not limited to clamping at both ends, clamping around the periphery, surface clamping, point clamping, etc. Specifically, in implementation, the external clamping structure 5 is preferably an elbow clamp type structure.

[0040] As Figure 3 shown in the figure, internal clamping structures 6 are provided on the left and right sides of the lower end of the upper fixing plate 1 and the left and right sides of the upper end of the lower fixing plate 2 and are matched with each other. Hollow portions 15 are provided on the left and right sides of the metal electrode plate 8. The internal clamping structures 6 pass through the hollow portions 15. When the internal clamping structures 6 are not continuous, seals 12 can also be designed around the clamping structures to ensure sealing. The materials of the seals 12 include but not limited to nitrile rubber, neoprene, silicone rubber, etc. The bonding glues can be selected as silicone, epoxy resin, acrylic structural glue, etc. As Figure 5 shown in the figure, the internal clamping structures 6 are preferably reinforcing ribs or ridges arranged in a staggered manner up and down and in multiple parallel rows, so that the concave and convex portions between the upper fixing plate 1 and the lower fixing plate 2 are embedded in each other.

[0041] AsFigure 4 As shown in the figure, the protective gas chamber 3 includes a first transverse groove 31, a second transverse groove 35, a first inclined groove 32, a second inclined groove 34, and a longitudinal groove 33. The first transverse groove 31 and the second transverse groove 35 are arranged in sequence front and back and are parallel to each other. The outer end of the first transverse groove 31 is connected to one end of the first inclined groove 32, and the outer end of the second transverse groove 35 is connected to one end of the second inclined groove 34. The first inclined groove 32 and the second inclined groove 34 extend obliquely outward from one end to the other end. The first inclined groove 32 and the second inclined groove 34 extend obliquely towards each other and are symmetrically arranged. The other end of the first inclined groove 32 and the other end of the second inclined groove 34 are connected by the longitudinal groove 33.

[0042] As Figure 4 shown in the figure, the protective gas chamber 3 further includes a first branch groove 36 and a second branch groove 37 arranged in sequence front and back. One end of the first branch groove 36 and the second branch groove 37 communicates with the inner side of the longitudinal groove 33. The first branch groove 36 is arranged obliquely backward from one end to the other end, and the second branch groove 37 is arranged obliquely forward from one end to the other end.

[0043] As Figure 6 shown in the figure, a sealing ring 12 can be provided on the outer side of the internal clamping structure 6. The sealing ring 12 is fixed to the upper end of the lower fixing plate 2. The sealing ring 12 is arranged in a square shape along the outer side of the lower fixing plate 2. The material of the sealing ring 12 includes but is not limited to nitrile rubber, neoprene, silicone rubber, etc. The bonding glue can be selected from silicone glue, epoxy resin, acrylic structural glue, etc.

[0044] As Figure 6 shown in the figure, a cover plate 13 can also be provided on the upper end of the upper fixing plate 1. The left and right sides of the cover plate 13 cover the protective gas chamber 3. The length of the cover plate 13 is shorter than the length of the upper fixing plate 1, and it does not affect the connection structure of the positioning pins 7 at the four corners of the upper fixing plate 1 and the lower fixing plate 2.

[0045] A plurality of exhaust ports 11 are provided on the front and back sides of the upper fixing plate 1 and the lower fixing plate 2. The exhaust ports 11 communicate with the protective gas chamber 3.

[0046] Embodiment 1

[0047] This embodiment provides a protective gas welding tooling and its process method for a fuel cell metal bipolar plate. For the structural details, see the appendix Figure 1, the structure of the shielding gas welding tooling includes an upper fixing plate 1, a lower fixing plate 2, a shielding gas chamber 3, an air inlet 4, an external clamping structure 5, an internal clamping structure 6, a positioning pin 7, a metal plate 8, and a quick plug 9. Among them, the upper fixing plate 1 and the lower fixing plate 2 form a tooling skeleton support mechanism, the shielding gas chamber 3 and the air inlet 4 form a tooling protection mechanism, and the external clamping structure 5, the internal clamping structure 6, and the positioning structure 7 form a tooling fastening mechanism. Welding areas corresponding in position are provided in the middle of the upper fixing plate 1, the lower fixing plate 2, and the metal plate 8.

[0048] The skeleton support mechanism is as Figure 2 shown. The upper fixing plate 1 and the lower fixing plate 2 are the main parts of the tooling. The shielding gas chamber 3, the air inlet 4, the external clamping structure 5, etc. are machined on them, which play the role of placing and stabilizing the metal plate 8. In this embodiment, the upper fixing plate 1 and the lower fixing plate 2 are preferably made of cast iron material.

[0049] The tooling protection mechanism is as Figure 3 shown. The shielding gas chamber 3 is located on the left and right sides of the welding area, and its shape matches the welding area of the metal plate 8. The shielding gas flows into the interior of the tooling through the air inlet 4, reaches the surface of the metal plate 8 through the shielding gas chamber 3, blows out the air and provides cooling. The tooling is connected to the shielding gas cylinder using the quick plug 9. In this embodiment, the shielding gas chamber 3 is divided into two parts. The number of air inlets 4 is a total of ten and they are all designed as circular openings to protect the flow field area and the inlet and outlet areas of the metal plate 8 respectively. The shielding gas used is preferably nitrogen.

[0050] As Figures 3 to 5 shown, the shielding gas chamber 3 includes a plurality of sequentially connected troughs: a first horizontal trough 31, a first inclined trough 32, a longitudinal trough 33, a second inclined trough 34, and a second horizontal trough 35. The first horizontal trough 31 and the second horizontal trough 35 are arranged in sequence front and back and are parallel to each other. The outer end of the first horizontal trough 31 is connected to one end of the first inclined trough 32, and the outer end of the second horizontal trough 35 is connected to one end of the second inclined trough 34. The first inclined trough 32 and the second inclined trough 34 extend obliquely outward from one end to the other end. The first inclined trough 32 and the second inclined trough 34 extend obliquely towards each other and are symmetrically arranged. The other end of the first inclined trough 32 and the other end of the second inclined trough 34 are connected by the longitudinal trough 33. The first inclined trough 32, the longitudinal trough 33, and the second inclined trough 34 form a trapezoidal structure. The trough extends in a trapezoidal structure, reducing the right-angle turns of the trough, being easy to machine, and having higher firmness compared to a rectangular structure.

[0051] As Figures 3 to 5As shown, the protective gas cavity 3 further includes a first branch groove 36 and a second branch groove 37 arranged in sequence from front to back. One end of the first branch groove 36 and the second branch groove 37 is communicated with the inner side of the longitudinal groove 33. The first branch groove 36 is inclined backward from one end to the other end, and the second branch groove 37 is inclined forward from one end to the other end. The first branch groove 36 and the second branch groove 37 expand the area in the middle of the protective gas cavity 3, so that the intake air flows evenly into the whole tooling.

[0052] The tooling fastening mechanism is as Figure 4 As shown, in this embodiment, the external clamping structure 5 preferably adopts an elbow clamp structure to lock the upper fixing plate 1 and the lower fixing plate 2, ensuring that the relative positions of the upper fixing plate 1, the lower fixing plate 2 and the metal electrode plate 8 do not change. After welding, it plays a role in lifting the upper fixing plate 1. Positioning is carried out by using the positioning pin 7. Pin holes are processed at the four corners of the upper fixing plate 1 and the lower fixing plate 2. Through the cooperation of the pin holes of the upper fixing plate 1, the lower fixing plate 2 and the metal electrode plate 8 with the positioning pin 7, the precise positioning of the metal electrode plate 8 is completed. The design of the above positioning structure prevents the problems of misplacement and reverse placement of the upper fixing plate 1 and the lower fixing plate 2. The internal clamping structure 6 is a plurality of rows of parallel reinforcing ribs or ridges arranged in a staggered manner up and down, so that the concave and convex parts between the upper fixing plate 1 and the lower fixing plate 2 are embedded in each other. In this embodiment, the internal clamping structure 6 preferably adopts a sheet-shaped reinforcing rib structure to press the metal electrode plate 8 tightly during welding, ensuring close contact between the metal electrode plates 8, avoiding virtual soldering and improving the welding quality.

[0053] The process method using the above tooling includes the following main steps:

[0054] (1) Select suitable upper fixing plate 1 and lower fixing plate 2 according to the metal electrode plate 8;

[0055] (2) Place the metal electrode plate 8 on the lower fixing plate 2, and then place the upper fixing plate 1 on the metal electrode plate 8. Use the internal clamping structure to cooperate with the hollow 15 to complete the positioning;

[0056] (3) Use the positioning pin 7 to complete the precise positioning and bonding of the upper fixing plate 1, the lower fixing plate 2 and the metal electrode plate 8;

[0057] (4) Use the external elbow clamp structure 5 to clamp the upper fixing plate 1 and the lower fixing plate 2, and the internal clamping structure 6 simultaneously presses the metal electrode plate 8 tightly; Open the valve of the nitrogen cylinder, and nitrogen flows into the upper fixing plate 1 and the lower fixing plate 2 through the air inlet 4 and fills the protective gas cavity 3, and then flows out from the outer surface of the upper fixing plate 1. Run the welding equipment to perform automatic welding;

[0058] (5) After welding is completed, open the external elbow clamp structure 5, lift the upper fixing plate 1, and take out the welded metal electrode plate 8.

[0059] In specific implementation, the gas shielded welding tooling and its process method for fuel cell metal plates involved in the present invention are directed to a variety of metal plates 8. Different metal plates 8 require different fixing plates, gas protection chambers 3, and internal clamping structures 6.

[0060] Embodiment 2

[0061] This embodiment provides another gas shielded welding tooling and its process method for fuel cell metal bipolar plates. The overall layout is shown in Figure 6 , and the tooling includes: upper fixing plate 1, lower fixing plate 2, gas protection chamber 3, air inlet 4, internal clamping structure 6, external clamping structure 5, quick plug 9, metal plate 8, limit block 10, exhaust port 11, sealing ring 12, and cover plate 13. Among them, the upper fixing plate 1 and the lower fixing plate 2 form the tooling skeleton mechanism, the gas protection chamber 3, the air inlet 4, the exhaust port 11, and the cover plate 13 form the tooling protection mechanism. The cover plate 13 is preferably a glass cover plate. The external clamping structure 5, the internal clamping structure 6, and the limit block 10 form the tooling fastening mechanism, and the sealing ring 12 forms the tooling sealing mechanism.

[0062] In this embodiment, the exhaust port 11 of the gas protection chamber 3 is designed on the side of the overall tooling. The tooling is connected to the gas protection cylinder using a quick plug 9. The cover plate 13 is bonded to the outer surface of the upper fixing plate 1 through silicone rubber to form a gas protection chamber. The protective gas flows into the interior of the tooling through the air inlet 4 and then flows out of the tooling through the exhaust port 11. The protective gas preferably selects argon.

[0063] In this embodiment, the external clamping structure 5 selects a pneumatic pressing structure, and the pressing area selects the two ends and the middle area of the tooling to ensure uniform force on the tooling. The tooling is designed with a limit structure, and through asymmetric design, problems such as incorrect placement and reverse placement of the tooling are prevented.

[0064] In this embodiment, a sealing groove is designed on the periphery of the upper fixing plate 1 and the lower fixing plate 2 for placing the sealing ring 14, and the sealing ring 14 is bonded to the tooling through silicone rubber.

[0065] In this embodiment, corresponding limit grooves 14 are provided on the front and rear sides of the upper fixing plate 1 and the lower fixing plate 2. The upper and lower ends of the limit block 10 are embedded in the above limit grooves 14 for positioning the upper fixing plate 1 and the lower fixing plate 2.

[0066] In this embodiment, the tooling skeleton mechanism is the same as that in Example 1 and will not be elaborated here.

[0067] The process method using the above tooling includes the following main steps:

[0068] (1) Select appropriate upper fixing plate 1 and lower fixing plate 2 according to the metal plate 8;

[0069] (2)Place the metal plate 8 on the lower fixing plate 2, place the limit block 10 in the limit groove 14 of the lower fixing plate 2, then buckle the upper fixing plate 1 on the metal plate 8, and use the internal clamping structure 6 to cooperate with the hollow 15 to complete the positioning;

[0070] (3)Use the positioning pin 7 to complete the precise positioning of the upper fixing plate 1, the lower fixing plate 2 and the metal plate 8;

[0071] (4)Use the external elbow clamp structure 5 to clamp the upper fixing plate 1 and the lower fixing plate 2, and the internal clamping structure 6 simultaneously completes the pressing of the metal plate 8. Open the valve of the argon gas cylinder, and the argon gas flows into the upper fixing plate 1 and the lower fixing plate 2 through the air inlet 4 and fills the protective gas chamber 3, and then discharges from the exhaust port 11. Run the welding equipment to perform automatic welding;

[0072] (5)After welding is completed, open the external clamping structure 5, lift the upper fixing plate 1, and take out the welded metal plate 8;

[0073] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A protective gas welding tooling for a fuel cell metal bipolar plate, characterized in that, it includes an upper fixing plate, a metal plate and a lower fixing plate which are arranged in sequence from top to bottom. The upper fixing plate, the metal plate and the lower fixing plate have the same length in the left-right direction and the same width in the front-back direction. Two protective gas cavities are provided on the left and right sides of the upper fixing plate. The protective gas cavities penetrate through the upper and lower ends of the upper fixing plate. The protective gas cavities are symmetrically arranged left and right. A plurality of air inlets are provided on the outer edges of the left and right ends of the upper fixing plate. The air inlets are open at the upper end of the upper fixing plate. The lower end of the air inlet is communicated with the protective gas cavity through a trachea. Each air inlet is correspondingly provided with a quick plug. The quick plug is installed on the upper part of the air inlet. The quick plug is used to connect the tooling with a protective gas cylinder. The four corners of the upper fixing plate, the metal plate and the lower fixing plate are connected by positioning pins. The upper fixing plate, the metal plate and the lower fixing plate are fastened by positioning pins and an external clamping structure. Internal clamping structures are provided on the left and right sides of the lower end of the upper fixing plate and the left and right sides of the upper end of the lower fixing plate and are matched with each other. The left and right sides of the metal plate are provided with hollow parts. The internal clamping structures pass through the hollow parts. The protective gas cavity includes multiple sections of grooves connected in sequence: a first horizontal groove, a first inclined groove, a longitudinal groove, a second inclined groove and a second horizontal groove. The first horizontal groove and the second horizontal groove are arranged in sequence from front to back and are parallel to each other. The outer end of the first horizontal groove is connected to one end of the first inclined groove. The outer end of the second horizontal groove is connected to one end of the second inclined groove. The first inclined groove and the second inclined groove extend obliquely outward from one end to the other end. The first inclined groove and the second inclined groove extend obliquely and symmetrically towards each other. The other end of the first inclined groove and the other end of the second inclined groove are connected by a longitudinal groove. The first inclined groove, the longitudinal groove and the second inclined groove form a trapezoidal structure. The protective gas cavity further includes a first branch groove and a second branch groove which are arranged in sequence from front to back. One end of the first branch groove and the second branch groove is communicated with the inner side of the longitudinal groove. The first branch groove is arranged obliquely backward from one end to the other end. The second branch groove is arranged obliquely forward from one end to the other end; The internal clamping structure is a plurality of rows of parallel reinforcing ribs or ridges arranged in a staggered manner up and down, so that the concave and convex parts between the upper fixing plate and the lower fixing plate are embedded in each other; It further includes a cover plate. The cover plate is located at the upper end of the upper fixing plate. The left and right sides of the cover plate cover the protective gas cavity. The length of the cover plate is shorter than the length of the upper fixing plate.

2. The protective gas welding tooling for a fuel cell metal bipolar plate according to claim 1, characterized in that, the external clamping structure is an elbow clamp structure.

3. The protective gas welding tooling for a fuel cell metal bipolar plate according to claim 1, characterized in that, the air inlet is a circular opening.

4. The protective gas welding tooling for a fuel cell metal bipolar plate according to claim 1, characterized in that, a sealing ring is provided on the outer side of the internal clamping structure. The sealing ring is fixed at the upper end of the lower fixing plate. The sealing ring is arranged in a square shape along the outer side of the lower fixing plate.

5. The gas shielded welding tooling for protecting the metal bipolar plate of a fuel cell according to claim 1, characterized in that, a plurality of exhaust ports are provided on the front and rear sides of the upper fixing plate and the lower fixing plate, and the exhaust ports are communicated with the protective gas chamber.

6. A process method using the tooling according to any one of claims 1-5, characterized in that, it includes the following steps: (1) Select a suitable welding tooling according to the plate type of the metal bipolar plate and the distribution of the welding area; (2) Place the lower fixing plate of the tooling on the working table of the welding equipment, place the metal plate flat on the upper surface of the lower fixing plate, and complete the positioning by cooperating with the internal clamping structure and the hollowing out; (3) After the preliminary placement and positioning of the metal plate are completed, place the upper fixing plate on the upper surface of the metal plate, position the upper fixing plate and the lower fixing plate through the positioning pins, and connect the air inlet of the tooling to the pipeline of the protective gas cylinder; (4) Use the external clamping structure to clamp the upper fixing plate, the metal plate and the lower fixing plate, operate the welding equipment to perform welding, introduce a protective gas with a suitable gas volume during the welding process to protect the surface of the metal plate and provide cooling; (5) After the welding process of the metal plate is completed, close the supply of the protective gas, open the external clamping structure and slowly lift the upper fixing plate, and take out the metal plate to weld the next pair of plates.

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