A fixture for laser welding of fuel cell bipolar plates

Abstract

The application discloses a clamp for laser welding of a fuel cell bipolar plate, comprising a base plate assembly and a cover plate assembly, wherein the cover plate assembly comprises a cover plate body and a plurality of equal-height blocks, a welding path is arranged between the equal-height blocks, a micro-motion gap is arranged between each equal-height block and the cover plate body, the equal-height blocks are connected with the cover plate body through elastic pressing block guide shaft assemblies, springs are further arranged between the equal-height blocks and the cover plate body, the pressing height of the springs is greater than the sum of the hole depths of a pair of spring holes, the base plate assembly comprises a base plate body and a base plate positioning pin assembly, the clamp is arranged through cooperation of the base plate assembly and the cover plate assembly, can effectively clamp the bipolar plate, is stable and reliable in clamping and will not damage the bipolar plate, can reserve a reasonable welding path, is convenient for laser rapid welding, is quick and simple in clamping process and does not need to be adjusted artificially, and the cover plate assembly can self-adaptively clamp the bipolar plate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bipolar plate welding fixture, and particularly relates to a fixture for laser welding of fuel cell bipolar plate. BACKGROUND

[0002] Fuel cell is a new power generation technology after the original power generation technology, and is also a pollution-free, high-efficiency, noiseless and continuous working power device. The principle of fuel cell is to convert chemical energy into electrical energy, and the final product is water, which is recognized as the most environmentally friendly technology and is called the ultimate clean fuel. Hydrogen-oxygen fuel cell is a kind of battery that uses oxygen as oxidant and hydrogen as fuel, and then converts the chemical energy generated by various chemical reactions of fuel into electrical energy. This kind of battery has many advantages such as large capacity, high specific energy, high conversion efficiency and wide power range, and bipolar plate, as one of the important components of fuel cell, plays a decisive role in the life and performance of the battery.

[0003] Metal bipolar plate is formed by sheet stamping, has good electrical conductivity, thermal conductivity and mechanical properties, high strength, good gas resistance, low processing cost and easy large-scale production, so that metal bipolar plate becomes the development direction of fuel cell bipolar plate. The metal bipolar plate is generally made of thin plate to form anode and cathode, and then the two are welded together to form a flow channel in the middle; in order to quickly and accurately weld the bipolar plate, a special welding fixture is needed to clamp the bipolar plate.

[0004] For example, Chinese patent application (publication number: CN110534764A) discloses a fuel cell metal bipolar plate welding fixture, which comprises a suction cup and a pressing plate. The first recess is arranged on the suction cup and matched with the first polar plate of the bipolar plate. The second recess is arranged on the pressing plate and matched with the second polar plate of the bipolar plate. The suction cup and the pressing plate are attracted together to press the bipolar plate tightly between the suction cup and the pressing plate. The welding fixture fixes the bipolar plate through the suction cup and the pressing plate. Since the outer contour of the bipolar plate is not a standard straight plate, the pressing plate is not conducive to the control of the gap when it is pressed down. Improper clamping force control can easily contact and damage the bipolar plate. SUMMARY

[0005] The present application aims at the problems existing in the prior art, and provides a fixture for laser welding of fuel cell bipolar plate.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is:

[0007] A kind of fixture for fuel cell bipolar plate laser welding, including bottom plate assembly for clamping bipolar plate and cover plate assembly, the cover plate assembly includes cover plate body, and the sub-block press plate is arranged floatingly below the cover plate body, the sub-block press plate is arranged below the cover plate body with the basic outline of the bipolar plate, the sub-block press plate is several non-contact isometric blocks, welding path is provided between several isometric blocks, and micro-motion gap is respectively provided between each isometric block and the cover plate body;The isometric block is connected with the cover plate body by elastic press block guide shaft assembly, and isometric block and the cover plate body are also correspondingly provided with several spring holes, and spring is respectively arranged in each pair of spring holes, and the compression height of the spring is greater than the sum of the hole depth of the pair of spring holes;The bottom plate assembly includes bottom plate body, and several bottom plate positioning pin assemblies are detachably arranged on the bottom plate body, and the bottom plate positioning pin assemblies are used for the positioning of bipolar plate, and several bushings are further provided on the bottom plate body, and the bushings are used to connect the positioning column on the cover plate body.

[0008] The fixture can effectively clamp the bipolar plate by the cooperation of the bottom plate assembly and the cover plate assembly, is stable and reliable, does not damage the bipolar plate, and can reserve a reasonable welding path to facilitate rapid laser welding, and the clamping process is quick and simple without manual adjustment, and the cover plate assembly can adaptively clamp the bipolar plate.

[0009] The cover plate assembly is a double-layer structure, the upper cover plate body performs overall up-down movement and is used to movably connect the lower sub-block press plate, and the sub-block press plate presses the bipolar plate when descending;The sub-block press plate is arranged by a plurality of isometric blocks, and is arranged in the length direction, the width direction and the inner and outer rings, so that the bipolar plate can be clamped more flexibly.

[0010] The micro-motion gap is provided between the isometric block and the cover plate body, and the gap still exists under the maximum clamping force, and the gas blowing protection effect is not affected by the excessive height of the cover plate;The micro-motion gap is adjusted by the deformation of the spring, the spring is independently arranged in the spring hole, and the compression height of the spring can limit the minimum micro-motion gap when ensuring basic deformation and position fine adjustment, so that the isometric block does not directly contact the cover plate body.

[0011] The elastic block guide shaft assembly has a guiding effect, and can move the cover plate body and the contour block in the same direction; generally, the spring is assembled on the elastic block guide shaft assembly, because the spring and the shaft sleeve are arranged together, not only can guide, but also can reduce the deviation force, but this arrangement may make the contour block directly contact with the cover plate body and eliminate the minimum gap; the spring is arranged separately in the application, although there is a small deviation force, but it can ensure the height difference, that is, the micro-motion gap, because a plurality of springs and elastic block guide shaft assemblies are arranged, the deviation force can be ignored for the whole, and has no substantial effect on clamping.

[0012] Further, the elastic block guide shaft assembly comprises a shaft sleeve, a T-shaped guide shaft and a connecting bolt, the cover plate body is provided with a T-shaped hole penetrating upward and downward, the contour block is provided with an upper sink hole and a lower sink hole arranged correspondingly with the T-shaped hole, the T-shaped guide shaft is sleeved with the shaft sleeve and arranged in the T-shaped hole, the lower end of the T-shaped guide shaft extends into the upper sink hole, and the connecting bolt penetrates upward from the lower sink hole into the upper sink hole and is screwed and fixed with the T-shaped guide shaft.

[0013] By adopting this connection mode, the contour block can be movably hung below the cover plate body, which can move together with the cover plate body on one hand, and can move upward relative to the cover plate body when subjected to the reaction force of the bipolar plate on the other hand; the T-shaped guide shaft has a guiding and connecting effect, and through the limiting of the T-shaped hole, the T-shaped guide shaft has a lowest lower limit position, and when ascending, the end portion thereof can penetrate out of the T-shaped hole, and the upper limit of floating is completed by relying on the spring arranged beside; the setting of the lower sink hole can hide the end portion of the connecting bolt, and cooperating with the setting of the upper sink hole, the lower end of the connecting bolt will not be exposed from the contour block whether descending or floating, so that the lower end surface of the contour block is ensured to be flat; the cooperation of the lower sink hole and the upper sink hole has a limiting effect around, which limits the upper end surface of the bolt head of the connecting bolt and the lower end portion of the T-shaped guide shaft.

[0014] Further, at least two groups of the elastic block guide shaft assemblies are connected to each contour block, and 1-3 spring holes are arranged on each contour block, and the spring holes are located between adjacent elastic block guide shaft assemblies.

[0015] Through such an arrangement, the stability of the contour block connection and movement can be ensured, and the springs can be arranged staggered.

[0016] Further, the spring is used for controlling the micro-motion gap, and when the spring is compressed to a compression height, the micro-motion gap is not more than 0.5 mm. That is, the height of the spring body is used to limit the micro-motion gap to the minimum.

[0017] Further, at least two inner and outer equal-height blocks are arranged on each edge in the width direction, and gaps between adjacent equal-height blocks are staggered on the inner and outer rings. Except for the welding path, these gaps are substantially staggered.

[0018] Since the profile of the entire sub-block pressing plate is formed by the equal-height blocks, and the equal-height blocks are intentionally staggered when arranged, it can avoid the occurrence of a through gap in a certain cross section; thus, corresponding gaps do not appear on both sides of the welding path at the same time, reducing the influence on the welding acceptance and the weld.

[0019] Further, the equal-height blocks include rectangular structures, L-shaped structures, and square structures with arc-shaped notches, and the square structures with arc-shaped notches are arranged at the four corners. At least one pair of equal-height blocks in the length direction is further provided with a matching arc-shaped protruding structure and an arc-shaped groove structure.

[0020] The arrangement of equal-height blocks of various shapes can flexibly assemble the pressing plate shape according to the shape of the bipolar plate, while pressing the bipolar plate and leaving the welding path.

[0021] Further, the welding path is at least one, and the welding path is a symmetric split structure. The cover plate body is provided with a laser welding groove corresponding to the welding path.

[0022] Further, the bottom plate positioning pin assembly includes a mounting seat embedded in the bottom plate body. The two sides of the mounting seat are connected to the bottom plate body by means of a countersunk head bolt. The middle part of the mounting seat is provided with a vertical through hole with a stepped structure. A positioning pin is sleeved in the vertical through hole. The middle part of the positioning pin is provided with a ring of clamping protrusions. The clamping protrusions abut against the stepped structure. A limiting spring is sleeved on the positioning pin below the clamping protrusions. The bottom of the mounting seat is provided with a sealing plate, and the lower end of the positioning pin penetrates through the sealing plate.

[0023] The bottom plate positioning pin assembly arranged in this assembly manner can be conveniently assembled and disassembled with the bottom plate body. The positioning pin has a floating positioning effect. When subjected to pressure, the positioning pin will retract to offset a part of the impact force and then rebound into the positioning hole, which can reduce the damage to the bipolar plate and also has a self-adjusting effect.

[0024] Further, the two sides of the bottom plate body are further provided with a clearance slot, and the side wall of the clearance slot is further connected with a side floating block. The clearance slot and the side floating block are arranged to facilitate the clamping and installation of the bottom plate body, and the bottom plate assembly can be clamped and transferred from this place.

[0025] Further, the inside of the cover plate body is also provided with a plurality of air channels, one end of the air channel is communicated to the welding path, the other end is communicated to the side wall of the cover plate body and is connected with an air nozzle connector, and the air channel is arranged to avoid the plurality of holes vertically arranged on the cover plate body. The gas protection is formed during welding, which is also beneficial to heat dissipation.

[0026] Compared with the prior art, the beneficial effects of the present application are: 1. The clamp can effectively clamp the bipolar plate through the cooperation of the bottom plate assembly and the cover plate assembly, the clamping is stable and reliable and will not damage the bipolar plate, and a reasonable welding path can be reserved, which is convenient for rapid laser welding, the clamping process is quick and simple, and manual adjustment is not required, and the cover plate assembly can self-adaptively clamp the bipolar plate; 2. The block pressing plate is arranged by a plurality of equal-height blocks, which are arranged as equal-height blocks in the length direction, width direction and inner and outer rings, so that the bipolar plate can be clamped more flexibly, each equal-height block can be self-adaptively adjusted according to different positions on the bipolar plate, so that a large pressing force can be achieved in a short stroke, and the cover plate body remains in a horizontal downward pressing state; 3. The setting of the micro-motion gap is beneficial to self-adaptive adjustment, and the gap still exists under the maximum clamping force, so that the gas blowing protection effect is not affected by the excessive height of the cover plate; the micro-motion gap is adjusted by the deformation of the spring, and the compression and height of the spring limit the minimum micro-motion gap, so that the equal-height blocks will not directly contact the cover plate body; 4. The elastic pressing block guide shaft assembly has a simple and ingenious structure, has the functions of limiting and guiding, can move the equal-height blocks with the cover plate body, and is good for the hidden setting of the connecting bolt; 5. The positioning pin has a floating positioning effect, and when subjected to pressure, the positioning pin will retract to offset part of the impact force and then rebound into the positioning hole, which can reduce the damage to the bipolar plate and also has a self-tuning effect. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a whole explosion schematic view of the clamp for laser welding of the bipolar plate of the fuel cell of the present application;

[0028] Figure 2 It is a bottom structure schematic view of the clamp for laser welding of the bipolar plate of the fuel cell of the present application;

[0029] Figure 3 It is a schematic view of the elastic pressing block guide shaft assembly and the spring arrangement of the present application;

[0030] Figure 4 It is a three-dimensional structure schematic view of the bottom positioning pin assembly of the present application;

[0031] Figure 5 It is a cross-sectional structure schematic view of the bottom positioning pin assembly of the present application;

[0032] Figure 6 Figure 1 is a schematic diagram of the welding path of the present application;

[0033] Figure 7 Figure 2 is a schematic diagram of the welding path of the present application;

[0034] In the figure: 1, cover plate body; 2, bottom plate body; 3, bipolar plate; 4, equal height block; 5, welding path; 6, micro-motion gap; 7, spring hole; 8, spring; 9, T-shaped hole; 10, T-shaped guide shaft; 11, shaft sleeve; 12, connecting bolt; 13, upper counterbore; 14, lower counterbore; 15, bottom plate positioning pin assembly; 1501, mounting seat; 1502, side wing; 1503, countersunk bolt; 1504, positioning pin; 1505, clamping protrusion; 1506, vertical through hole; 1507, step structure; 1508, limiting spring; 1509, sealing plate; 16, bushing; 17, positioning column; 18, laser groove; 19, accommodation groove; 20, side floating block; 21, air nozzle connector. DETAILED DESCRIPTION

[0035] The technical solutions of the present application will be described clearly and completely below in combination with the drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0036] In the description of the present application, it should be noted that the terms "intermediate", "upper", "lower", "left", "right", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" and the like are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0037] Embodiment one:

[0038] As Figures 1-5As shown, a fixture for laser welding of fuel cell bipolar plates, comprising a base plate assembly for clamping the bipolar plate 3 and a cover plate assembly, the cover plate assembly comprising a cover plate body 1 and a segmented pressing plate floatingly arranged below the cover plate body 1, the segmented pressing plate being arranged below the cover plate body 1 in the basic contour of the bipolar plate 3, the segmented pressing plate being a plurality of non-contacting equal-height blocks 4, a welding path 5 being provided between the equal-height blocks 4, a micro-motion gap 6 being provided between each equal-height block 4 and the cover plate body 1; the equal-height blocks 4 are connected to the cover plate body 1 through an elastic pressing block guide shaft assembly, a plurality of spring holes 7 are provided between the equal-height blocks 4 and the cover plate body 1 in one-to-one correspondence, a spring 8 is provided in each pair of spring holes 7, and the compression height of the spring 8 is greater than the sum of the hole depths of the pair of spring holes 7; the base plate assembly comprises a base plate body 2 and a plurality of base plate positioning pin assemblies 15 detachably arranged on the base plate body 2, the base plate positioning pin assemblies 15 being used for positioning the bipolar plate 3, and a plurality of bushings 16 are further provided on the base plate body 2, the bushings 16 being used for connecting positioning columns 17 on the cover plate body 1.

[0039] The fixture can effectively clamp the bipolar plate 3 through the cooperation of the base plate assembly and the cover plate assembly, the clamping is stable and reliable and will not damage the bipolar plate 3, and a reasonable welding path 5 can be reserved to facilitate rapid laser welding, the clamping process is quick and simple and does not require manual adjustment, and the cover plate assembly can self-adaptively clamp the bipolar plate.

[0040] The cover plate assembly has a double-layer structure, the cover plate body 1 on the top performs overall up-down movement and is used for movably connecting the segmented pressing plate below, and the segmented pressing plate will press the bipolar plate 3 when descending; the segmented pressing plate is arranged by a plurality of equal-height blocks 4, which are arranged in the length direction, the width direction and the inner and outer rings, so that the bipolar plate 3 can be clamped more flexibly.

[0041] The micro-motion gap 6 is provided between the equal-height blocks 4 and the cover plate body 1, and the gap still exists under the maximum clamping force, and the blow protection effect will not be affected by the excessively high cover plate; the micro-motion gap 6 is adjusted by the deformation of the spring 8, the spring 8 is independently arranged in the spring hole 7, and when ensuring basic deformation and position fine adjustment, the compression height of the spring 8 can limit the minimum micro-motion gap to ensure that the equal-height blocks will not directly contact the cover plate body.

[0042] The elastic block guide shaft assembly has a guiding effect, and can make the cover plate body 1 and the equal-height blocks 4 move in the same direction; generally, a spring is assembled on the elastic block guide shaft assembly, because the spring and the shaft sleeve are arranged together, not only can guide, but also can reduce the deviation force, but this arrangement mode can make the equal-height blocks directly contact with the cover plate body and eliminate the minimum gap; therefore, the spring 8 is arranged separately in the application, although there is a small deviation force, but can ensure the height difference, that is, the micro-motion gap 6, because a plurality of springs and elastic block guide shaft assemblies are arranged, the deviation force can be ignored for the whole, and does not have substantial influence on clamping.

[0043] When clamping, the bipolar plate 3 is placed on the bottom plate body 2 and positioned and limited by the bottom plate positioning pin assembly 15, then the cover plate body 1 is lowered, the positioning column 17 on the cover plate body 1 is sleeved into the bushing 16 in advance, to form the basic positioning and limiting and guiding effect between them; continue to lower, the sub-block pressing plate gradually presses the bipolar plate 3, and each equal-height block 4 can be self-adaptively adjusted according to different positions on the bipolar plate 3, to ensure that a large pressing force is achieved in a short stroke, and the cover plate body 1 still maintains the horizontal downward pressing state, but will not clamp and damage the bipolar plate 3; after clamping is stable, laser welding is performed along the welding path, and after welding is completed, the cover plate body is upwardly withdrawn to realize separation.

[0044] Further, the elastic block guide shaft assembly comprises a shaft sleeve 11, a T-shaped guide shaft 10 and a connecting bolt 12, the cover plate body 1 is provided with a T-shaped hole 9 penetrating upward and downward, the equal-height block 4 is provided with an upper sink hole 13 and a lower sink hole 14 corresponding to the T-shaped hole 9, the T-shaped guide shaft 10 is sleeved with the shaft sleeve 11 and arranged in the T-shaped hole 9, the lower end of the T-shaped guide shaft 10 extends into the upper sink hole 13, the connecting bolt 12 penetrates upward from the lower sink hole 14 into the upper sink hole 13 and is screwed and fixed with the T-shaped guide shaft 10, the connecting bolt 12 is screwed into the T-shaped guide shaft, and is coaxially arranged.

[0045] With this connection mode, the movable equal-height block 4 can be hung below the cover plate body 1, which can move together with the cover plate body 1 and move upward relative to the cover plate body 1 when subjected to the reaction force of the bipolar plate 3; the T-shaped guide shaft 10 has a guiding and connecting effect, and through the limiting of the T-shaped hole 9, the T-shaped guide shaft 10 has a lowest lower limit position, and when moving upward, the end portion can pass out of the T-shaped hole 9, and the upper limit of the floating is completed by relying on the spring arranged beside; the setting of the sunken hole 14 can hide the end portion of the connecting bolt 12, and in cooperation with the setting of the sunken hole 13, the lower end of the connecting bolt 12 will not be exposed from the equal-height block 4 whether it is moving downward or floating upward, which ensures the flatness of the lower end surface of the equal-height block 4; the cooperation of the sunken hole 14 and the sunken hole 13 has a limiting effect around, which limits the upper end surface of the bolt head of the connecting bolt 12 and limits the lower end portion of the T-shaped guide shaft 10.

[0046] Further, at least two groups of the elastic pressing block guide shaft assemblies are connected to each equal-height block 4, and two or three spring holes 7 are arranged on each equal-height block 4, and the spring holes 7 are located between adjacent elastic pressing block guide shaft assemblies.

[0047] Through such a setting, the stability of the connection and movement of the equal-height block can be ensured, and the springs can be arranged staggered.

[0048] Further, the spring 8 is used to control the micro-motion gap 6, and when the spring 8 is compressed to a compression height, the micro-motion gap 6 is not more than 0.5 mm. That is, the height of the spring body is used to limit the micro-motion gap to the minimum, which ensures the compression while not affecting the air blowing.

[0049] Further, at least two inner and outer equal-height blocks 4 are arranged in the width direction on each side, and the gaps between adjacent equal-height blocks 4 are arranged staggered on the inner and outer rings. Except for the welding path 5, these gaps are basically arranged staggered.

[0050] Since the profile of the entire divided pressing plate is formed by the equal-height blocks 4, the equal-height blocks 4 are intentionally arranged staggered, which can avoid the occurrence of a through gap in a certain cross section; thus, corresponding gaps will not occur on both sides of the welding path at the same time, which reduces the influence on the welding receiving force and the weld.

[0051] Further, the equal-height block 4 includes a rectangular structure, an L-shaped structure, and a square structure with an arc-shaped notch, the square structure with an arc-shaped notch is arranged at the four corners to leave a connection position of the positioning column, and at least one pair of the equal-height blocks 4 are further provided with a matching arc-shaped protruding structure and an arc-shaped groove structure in the length direction to adapt to the arc-shaped weld on the bipolar plate.

[0052] The setting of the equal-height blocks of various shapes can flexibly form the pressing plate shape according to the shape of the bipolar plate 3, and leave the welding path while pressing the bipolar plate.

[0053] Further, the bottom plate positioning pin assembly 15 comprises a mounting seat 1501 embedded in the bottom plate body 2, the two side wings 1502 of the mounting seat 1501 are connected with the bottom plate body 2 through counterbores 1503 respectively, the middle part of the mounting seat 1501 is provided with a vertical through hole 1506 with a stepped structure 1507, the vertical through hole 1506 is sleeved with a positioning pin 1504, the middle part of the positioning pin 1504 is provided with a ring of clamping protrusions 1505, the clamping protrusions 1505 abut at the stepped structure 1507, the positioning pin below the clamping protrusions 1505 is sleeved with a limiting spring 1508, and the bottom of the mounting seat 1501 is provided with a sealing plate 1509, and the lower end of the positioning pin 1504 penetrates through the sealing plate 1509.

[0054] The bottom plate positioning pin assembly 15 arranged in this way can be conveniently assembled and disassembled with the bottom plate body 2, and the positioning pin 1504 has a floating positioning effect, that is, when pressed, the positioning pin 1504 will retract to offset part of the impact force and then rebound into the positioning hole, which can reduce the damage to the bipolar plate and also has a self-adjusting effect.

[0055] Further, the two sides of the bottom plate body 2 are also respectively provided with a giving slot 19, and the side wall in the giving slot 19 is also connected with a side floating block 20. The setting of the giving slot 19 and the side floating block 20 facilitates the clamping and installation of the bottom plate body 2, and the bottom plate assembly can be clamped and transferred from this place, and the connection mode of the side floating block 20 is similar to that of the equal-height block.

[0056] Further, the inside of the cover plate body 1 is also provided with a plurality of air channels, one end of the air channel is communicated to the laser groove 18, the other end is communicated to the side wall of the cover plate body 1 and connected with an air nozzle connector 21, and the air channel avoids a plurality of holes vertically arranged on the cover plate body. The air channel can blow air, form gas protection during welding, and also facilitate heat dissipation.

[0057] Embodiment two:

[0058] The embodiment provides a welding path of a symmetrical split structure.

[0059] As Figure 6 and Figure 7As shown, the welding path 5 is two, the welding path 5 is a symmetrical split structure, the cover plate body 1 is provided with a laser (welding) groove corresponding to the welding path 5. The symmetrical welding path can be completely welded by flipping and converting.

[0060] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are only by way of example and that modifications, changes, substitutions and variations can be made by those skilled in the art without departing from the spirit and scope of the application, which is defined solely by the claims and their equivalents.

Claims

1. A fixture for laser welding of fuel cell bipolar plates comprising a base plate assembly and a cover plate assembly for clamping the bipolar plates, characterized in that, The cover plate assembly comprises a cover plate body and a sub-block pressing plate floatingly arranged below the cover plate body, the sub-block pressing plate is arranged below the cover plate body in the basic profile of the bipolar plate, the sub-block pressing plate is a plurality of mutually non-contacting equal-height blocks, a welding path is arranged between the plurality of equal-height blocks, a micro-motion gap is respectively arranged between each equal-height block and the cover plate body, and the micro-motion gap still exists under the maximum clamping force; the equal-height blocks are connected with the cover plate body through an elastic pressing block guide shaft assembly, a plurality of spring holes are correspondingly arranged between the equal-height blocks and the cover plate body, a spring is respectively arranged in each pair of spring holes, and the pressing height of the spring is greater than the sum of the hole depths of the pair of spring holes; the bottom plate assembly comprises a bottom plate body and a plurality of bottom plate positioning pin assemblies arranged on the bottom plate body in a detachable manner, the bottom plate positioning pin assemblies are used for positioning the bipolar plate, a plurality of bushings are further arranged on the bottom plate body, and the bushings are used for connecting positioning columns on the cover plate body; the elastic pressing block guide shaft assembly comprises a shaft sleeve, a T-shaped guide shaft and a connecting bolt, a T-shaped hole penetrating up and down is arranged on the cover plate body, upper and lower sink holes corresponding to the T-shaped hole are arranged on the equal-height blocks, the T-shaped guide shaft is sleeved with the shaft sleeve and arranged in the T-shaped hole, the lower end of the T-shaped guide shaft extends into the upper sink hole, and the connecting bolt penetrates from the lower sink hole into the upper sink hole and is screw-connected and fixed with the T-shaped guide shaft; at least two groups of the elastic pressing block guide shaft assemblies are connected to each equal-height block, and 1-3 spring holes are arranged on each equal-height block, and the spring holes are located between adjacent elastic pressing block guide shaft assemblies.

2. The fixture for laser welding of fuel cell bipolar plates according to claim 1, wherein At least two groups of the elastic pressing block guide shaft assemblies are connected to each equal-height block, 1-3 spring holes are arranged on each equal-height block, and the spring holes are located between adjacent elastic pressing block guide shaft assemblies.

3. The fixture for laser welding of fuel cell bipolar plates according to claim 1, wherein At least two equal-height blocks are arranged on each side in the width direction, and the gaps between adjacent equal-height blocks are staggered on the inner and outer rings.

4. The fixture for laser welding of fuel cell bipolar plates of claim 1, wherein, The equal-height blocks comprise rectangular structures, L-shaped structures and square structures with arc-shaped notches, the square structures with arc-shaped notches are arranged at the four corners, and at least one pair of the equal-height blocks in the length direction is further provided with a matching arc-shaped protruding structure and an arc-shaped groove structure.

5. The fixture for laser welding of fuel cell bipolar plates of claim 1, wherein, The welding path is at least one, the welding path is a symmetric split structure, and the cover plate body is provided with a laser welding groove corresponding to the welding path.

6. The fixture for laser welding of fuel cell bipolar plates of claim 1, wherein, The bottom plate positioning pin assembly comprises a mounting seat embedded in the bottom plate body, both sides of the mounting seat are connected with the bottom plate body through counterbores, a vertical through hole with a stepped structure is arranged in the middle of the mounting seat, a positioning pin is sleeved in the vertical through hole, a clamping protrusion is arranged on the middle of the positioning pin, the clamping protrusion abuts at the stepped structure, a limiting spring is sleeved on the positioning pin below the clamping protrusion, and the bottom of the mounting seat is provided with a sealing plate, and the lower end of the positioning pin penetrates out of the sealing plate.

7. The fixture for laser welding of fuel cell bipolar plates of claim 1, wherein, Both sides of the bottom plate body are further provided with a displacement slot, and a side floating block is further connected to the side wall in the displacement slot.

8. The fixture for laser welding of fuel cell bipolar plates of claim 1, wherein, The inside of the cover plate body is also provided with a plurality of air channels, one end of the air channels is communicated to the welding path, the other end is communicated to the side wall of the cover plate body and is connected with an air nozzle connector, and the air channels are arranged away from the plurality of vertically arranged holes on the cover plate body.

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