Bipolar plate automatic welding equipment

Abstract

The invention relates to the technical field of bipolar plate welding, and discloses bipolar plate automatic welding equipment which comprises a welding chamber and a mechanical arm conveying rail, a mechanical arm places a bipolar plate body on a welding platform arranged in the welding chamber through the conveying rail, and the welding platform is provided with an eddy current generating end and a shunting block. A nozzle for spraying inert gas is arranged in the welding chamber, the vortex generating end is arranged at the airflow outlet end, so that airflow passes through the vortex generating end to form a Karman vortex street, the vortex street horizontally flows and flows along the welding side of the bipolar plate body, and a flow dividing block is arranged between the vortex generating end and the bipolar plate body and is used for dividing the welding side of the bipolar plate body. The shunting block is used for separating two vortexes with opposite rotating directions in the vortex street and guiding one vortex to the edge of the bipolar plate body vertical to the direction of the original vortex.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bipolar plate welding, in particular to a kind of bipolar plate automatic welding equipment. BACKGROUND

[0002] Bipolar plate is the core component in fuel cell and flow battery, it is like the "skeleton" and "blood vessel" of battery, bears multiple key roles, from structure, it is usually thin plate with precision flow channel, one side is connected with anode, the other side is connected with cathode, therefore named bipolar, its main function is firstly electrically conductive-single cell unit is connected into stack, efficiently collects and transports current;Secondly, flow guide-the precision etched flow channel on plate surface is like highway, ensure that fuel (such as hydrogen) and oxidant (such as air) are evenly distributed to the entire electrode surface;At the same time, it also needs to be responsible for heat dissipation and drainage, maintain the stable working temperature of battery, and discharge the water generated by reaction in time, prevent water, in addition, bipolar plate must have excellent corrosion resistance, high airtightness and sufficient mechanical strength, its material develops from early graphite metal to today's composite material, always pursues better electrical conductivity, lighter weight and lower cost, it can be said that the performance of bipolar plate directly determines the power density, efficiency and life of battery stack, is the key link to promote fuel cell technology to commercialization.

[0003] Bipolar plate is easy to produce splashing in welding process, that is, molten metal particles are splashed out of molten pool and solidified on the surface of workpiece, because inert gas needs to be sprayed to welding position by nozzle in welding process to protect welding area, the flow rate and angle of flowing gas are not suitable, cannot effectively suppress plasma cloud or excite liquid molten pool, leading to form undercut or surface contamination of welding area. SUMMARY

[0004] (I) The technical problem solved: in view of the shortcomings of the prior art, the present application provides a kind of bipolar plate automatic welding equipment, with the advantages of stable welding and less splashing, solve the problem of welding splashing.

[0005] (II) Technical scheme: in order to realize the above-mentioned stable welding and less splashing, the present application provides the following technical scheme: a kind of bipolar plate automatic welding equipment, including welding chamber and mechanical arm transport track, mechanical arm is placed in the welding platform set in welding chamber by transport track with bipolar plate body, the welding platform is equipped with vortex generation end and shunt block, the welding chamber is equipped with the nozzle that sprays inert gas, and vortex generation end is arranged at the gas outlet end, so that the gas flow forms karman vortex street after passing through vortex generation end, vortex street presents horizontal flow, and flows along the welding side of bipolar plate body, vortex generation end and bipolar plate body are equipped with shunt block, the shunt block separates the two vortexes in vortex street with opposite rotation directions, and one vortex is introduced to the edge of bipolar plate body which is perpendicular to the original vortex direction.

[0006] The vortex generating end is a spoiler column, and the spoiler column is airfoil-shaped.

[0007] The spoiler column in the vortex generating end is provided with at least two, and the spoiler columns are arranged in a staggered manner with a spacing of 1.5 times the diameter of the column.

[0008] The flow splitting block is Y-shaped, the bifurcation angle is 15°, one side of the flow direction of the jet flow of the nozzle is a horizontal plane, and the other side is an arc-shaped wall surface.

[0009] The flow stabilizing groove is provided with a groove on one side of the bipolar plate body, and the overall length of the flow stabilizing groove is greater than the side of the corresponding bipolar plate body.

[0010] The groove of the flow stabilizing groove is arc-shaped, and the overall height of the flow stabilizing groove is higher than the bipolar plate body.

[0011] The surface of the groove of the flow stabilizing groove adopts low-roughness polishing.

[0012] (Three) beneficial effects: compared with the prior art, the bipolar plate automatic welding equipment provided by the application has the following beneficial effects: 1. The bipolar plate automatic welding equipment converts the inert gas flow into alternating spiral vortexes through the vortex generating end, and then precisely guides the flow through the flow splitting block, so that the single-side vortex rotates in the form of an umbrella to completely wrap the welding area. This dynamic air curtain forms a three-dimensional surrounding protection, no matter how the welding torch changes, the molten pool is always in the center of the air curtain, which completely isolates the air from entering, significantly inhibits oxidation, nitridation and other defects, and the centrifugal force effect of the vortex can force the welding fume and spatter from the center of the molten pool to the periphery, thereby avoiding the impurities from being rolled into the weld, so as to improve the purity and surface flatness of the weld. The low-speed high-pressure inner gas flow guided by the flow splitting block contacts the molten pool, which not only relieves the impact force of the high-speed gas flow on the molten metal, effectively prevents undercutting and welding, but also prolongs the gas-metal contact time to strengthen the heat conduction efficiency, accelerates the solidification and crystallization of the molten pool, and makes the grain structure more dense. In addition, the structure also brings a number of implicit gains. The stability of the welding process is improved, the heat input control is more accurate, and the risk of deformation of the bipolar plate is reduced; the expansion of the air curtain coverage range allows higher welding speed to be used; the compression effect of the vortex on the arc also increases the consistency of the penetration, which is particularly suitable for multi-pass repeated welding scenes. This gas-flow cooperative control mechanism ultimately forms multiple positive gains in improving the welding quality, production efficiency and process repeatability.

[0013] 2、The bipolar plate automatic welding equipment, by adopting the wing type spoiler column as the vortex generating end, and making it staggered arrangement, first significantly optimizes the generation quality of the karman vortex street from the source, the wing type design can effectively guide the gas flow, maximally reduces unnecessary flow separation and energy dissipation, makes the vortex street start more quickly and the form more stable, and the staggered arrangement layout not only significantly enhances the overall strength and regularity of the vortex street, but also ensures that a uniform, dense and stable vortex air curtain can be formed in the width direction of the welding platform, on this basis, the Y-shaped flow divider divides the strong composite vortex into two with its precise 15-degree bifurcation angle, and guides one of the vortexes to accurately turn to cover the welding edge of the bipolar plate. This process is completed in the flow channel composed of a horizontal plane and an arc-shaped wall, the arc-shaped wall ensures smooth change of the airflow direction, avoids turbulence and pressure loss caused by sudden turning, thereby converting the gas kinetic energy into effective work of forming a protective air curtain with almost no loss, it generates a rotating protective air curtain with higher strength and better stability, the "umbrella-shaped" vortex can completely isolate air and provide dynamic protection with no dead angle, greatly improving the purity of the weld, secondly, thanks to more stable vortex and pure one-way rotating airflow after flow division, the centrifugal force slag removal effect is more significant, which can timely separate the welding spatter from the molten pool area, thereby obtaining a weld with smoother surface and no internal defects, thirdly, the low-speed high-pressure airflow with smooth transition interacts with the molten pool more gently and persistently, which not only perfectly suppresses spatter and cavitation, but also accelerates the solidification and crystallization process of the molten pool by enhancing the heat conduction capacity, thereby refining the weld grain, improving the mechanical strength and corrosion resistance of the weld. In addition, the structure also brings the previously unmentioned implicit advantages Since the airflow energy loss is very small, it can effectively reduce the consumption of inert gas while achieving the same or even better protection effect, realize energy saving and consumption reduction; at the same time, the whole system runs more smoothly, and the regularity of the vortex street is stronger, which reduces the requirement for equipment maintenance frequency, and further guarantees the consistency of welding quality in mass production and long-time production, comprehensively improves the reliability and economy of the equipment.

[0014] 3、The bipolar plate automatic welding equipment, through the additional steady flow tank on the bipolar plate welding side, is the key point of the whole gas curtain protection system, which realizes the fundamental change from the guidance of air flow to the active shaping and maintaining. The arc-shaped groove of the steady flow tank is not a passive channel, but a precisely designed flow field forming cavity. The length and height of the cavity ensure that the vortex can be effectively tamed and regularized before reaching the workpiece. The polished inner wall with low roughness greatly reduces the wall friction resistance, providing a nearly lossless track for the vortex, so that the rotational kinetic energy of the vortex can be maximally preserved. This means that the pure and single-directional umbrella-shaped vortex guided from the flow divider can maintain its shape and energy after entering the arc-shaped cavity of the steady flow tank, so that it can cover the entire welding path with nearly complete strength and stability, realizing the inert gas protection for the welding area without attenuation for a long time. The maintenance of the vortex intensity is directly equivalent to the extension of the "freshness period" of the protection gas curtain. Even for long welds, the end can also enjoy the same dense gas coverage as the starting point, completely eliminating the end oxidation problem caused by airflow attenuation and ensuring the uniformity of the composition and performance of the entire weld. Secondly, it significantly improves the robustness of the process. The more stable flow field has higher tolerance to fluctuations in process parameters such as welding speed and gas flow, making the welding process more stable and easier to control and repeat. In addition, the arc-shaped structure of the steady flow tank can constrain the vortex and prevent it from diffusing too early, thereby concentrating the protective gas on the molten pool area, further improving the protection efficiency without increasing the total gas consumption. It prepares an ideal gas environment for the upcoming welding molten pool, making the area where the welding torch passes a perfect protection area rather than a temporary air driving area, which is particularly beneficial to the instantaneous quality of the weld starting point. Finally, the steady flow tank, together with the vortex generation end and the flow divider, forms a full-process optimization system from generation, guidance to maintenance, pushing the reliability, consistency and efficiency of dynamic gas curtain protection to a new height. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a schematic diagram of the welding assembly line of the present application; Figure 2 is a schematic diagram of the structure of the present application; Figure 3 is a schematic diagram of the vortex of the present application; Figure 4 is a schematic diagram of the steady flow tank of the present application.

[0016] In the figure: 1, welding chamber; 2, vortex generation end; 11, welding platform; 21, flow divider; 22, steady flow tank; 101, bipolar plate body. DETAILED DESCRIPTION

[0017] Clearly, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present application.

[0018] Please refer to Figures 1-4 The bipolar plate automatic welding device comprises a welding chamber 1 and a mechanical arm conveying track. The mechanical arm places the bipolar plate body 101 on the welding platform 11 provided in the welding chamber 1 through the conveying track. The welding platform 11 is provided with a vortex generating end 2 and a flow dividing block 21. The welding chamber 1 is provided with a nozzle for spraying inert gas. The vortex generating end 2 is arranged at the gas flow outlet end, so that the gas flow forms a Karman vortex street after passing through the vortex generating end 2. The vortex street flows horizontally along the welding side of the bipolar plate body 101. The flow dividing block 21 is arranged between the vortex generating end 2 and the bipolar plate body 101. The flow dividing block 21 separates the two vortexes in the vortex street with opposite rotating directions, and guides one vortex to the edge of the bipolar plate body 101 which is perpendicular to the original vortex direction.

[0019] When the fluid flows through a non-streamlined object at a certain speed, two rows of alternating and opposite rotating periodic vortices are generated in the wake of the object. This regular vortex array is called a Karman vortex street. The vortices are not generated on both sides of the object at the same time, but one side generates a vortex and then falls off, and the other side generates and falls off, and so on. After the vortex street is separated by the flow dividing block 21, the single-side vortex is like a rotating umbrella, which can cover a wider area and wrap the welding point in the center of the air curtain. No matter how the welding direction changes, it can provide more comprehensive protection. The centrifugal force generated by the vortex gas flow can throw these harmful particles outward from the center of the vortex, significantly improving the welding efficiency and stability of the penetration depth. In the complex flow of the Karman vortex street, the vortex is not isolated. It is born in the wake of the cylinder and is strongly affected by the main flow, the other row of vortexes and the pressure gradient. According to the pressure difference formed by the superposition of the main flow direction and speed of the vortex, the inside of the vortex (the side close to the other row of vortexes) and the outside (the side away from the other row) will have different speeds. The outside gas flow is consistent with the main flow direction, forming a high-speed low-pressure area, while the inside gas flow is opposite to the main flow direction, forming a low-speed high-pressure area. Through the action of the flow dividing block 21, the inside gas flow contacts the welding point, so that the molten metal contacts the low-speed gas flow, avoiding the generation of spatter and cavitation, and improving the welding quality. At the same time, the contact time is increased, which is also beneficial to heat conduction and accelerates the welding solidification efficiency.

[0020] The vortex generating end 2 is a spoiler column, which is airfoil-shaped to reduce flow separation. The spoiler column is provided with at least two, and the spoiler columns are staggered with a spacing of 1.5 times the column diameter, so as to increase the vortex street strength and optimize the vortex street formation. The flow splitter 21 is Y-shaped with a bifurcation angle of 15°. The flow direction of the gas flow jetted out of the nozzle is on one side a horizontal plane and on the other side an arc-shaped wall surface, so as to ensure smooth transition of the gas flow and reduce energy loss.

[0021] Referring to Figure 4 The bipolar plate body 101 is provided with a flow stabilizing groove 22 on the welding side. The flow stabilizing groove 22 is provided with a groove on one side of the bipolar plate body 101. The overall length of the flow stabilizing groove 22 is greater than the corresponding side of the bipolar plate body 101. The groove of the flow stabilizing groove 22 is arc-shaped, and the overall height of the flow stabilizing groove 22 is higher than the bipolar plate body 101. In essence, it is changed from passive guidance to active shaping of the flow field, which can have a very significant stabilizing effect on the vortex. The surface of the groove of the flow stabilizing groove 22 is polished with low roughness. The rotational kinetic energy of the vortex is the fundamental reason for its existence. The frictional resistance of the groove wall will continuously consume the energy of the vortex, causing its speed to drop, its size to shrink, and eventually to dissipate prematurely. The low-roughness surface significantly reduces the wall shear stress, allowing the vortex to maintain its rotational strength for a longer period of time.

[0022] Working principle: the mechanical arm places the bipolar plate body 101 on the welding platform 11 provided in the welding chamber 1 through the transportation track, the welding platform 11 is provided with a vortex generating end 2 and a flow dividing block 21, the welding chamber 1 is provided with a nozzle for spraying inert gas, and the vortex generating end 2 is arranged at the gas flow outlet end, so that the gas flow passes through the vortex generating end 2 to form a Karman vortex street, the vortex street flows horizontally along the welding side of the bipolar plate body 101, the flow dividing block 21 is arranged between the vortex generating end 2 and the bipolar plate body 101, the flow dividing block 21 separates the two vortexes in the vortex street with opposite rotating directions, and one vortex is guided to the edge of the bipolar plate body 101 which is perpendicular to the original vortex direction, when the fluid flows through a non-streamlined object at a certain speed, two rows of periodic vortices with opposite rotating directions are generated in the wake of the object, and the regular vortex array is called a Karman vortex street, the vortices are not generated on both sides of the object at the same time, but one side generates a vortex and falls off, and then the other side generates and falls off, and the cycle is repeated, after the vortex street is separated by the flow dividing block 21, the single-side vortex is like a rotating umbrella, which can cover a wider area and wrap the welding point in the center of the air curtain, no matter how the welding direction changes, it can provide more comprehensive protection, the centrifugal force generated by the vortex gas flow can throw these harmful particles outwards from the center of the vortex, significantly improving the welding efficiency and penetration stability, in the complex flow of the Karman vortex street, the vortex is not isolated, it is born in the wake of the cylinder and is strongly affected by the main flow, another row of vortexes and pressure gradient, according to the pressure difference formed by the superposition of the main flow direction and speed of the vortex, the inside of the vortex (the side close to the other row of vortexes) and the outside (the side away from the other row) will have different speeds, the outside gas flow is consistent with the main flow direction, forming a high-speed low-pressure area, while the inside gas flow is opposite to the main flow direction, forming a low-speed high-pressure area, through the action of the flow dividing block 21, the inside gas flow contacts the welding position, so that the molten metal contacts the low-speed gas flow, avoiding the generation of spatter and cavitation, and improving the welding quality, at the same time, the contact time is increased, which is also beneficial to heat conduction and speeds up the welding solidification efficiency.

[0023] It should be noted that, in this text, relational terms such as first and second are used only to distinguish one entity or operation from another, and do not necessarily require or imply any actual such relationship or order between these entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment. Without more limitations, the element defined by the statement "including a" does not exclude the presence of other identical elements in the process, method, article or equipment including the element.

[0024] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and adaptions can be made without departing from the spirit and scope of the present application, which is defined by the following claims and their equivalents.

Claims

1. An automatic bipolar plate welding device, comprising a welding chamber (1) and a robotic arm transport track, wherein the robotic arm places the bipolar plate body (101) onto a welding platform (11) provided in the welding chamber (1) via the transport track, characterized in that: The welding platform (11) is provided with a vortex generating end (2) and a flow divider (21). The welding chamber (1) is provided with a nozzle for spraying inert gas, and the vortex generating end (2) is located at the airflow outlet end, so that the airflow passes through the vortex generating end (2) to form a Karman vortex street. The vortex street flows horizontally and flows along the welding side of the bipolar plate body (101). A flow divider (21) is provided between the vortex generating end (2) and the bipolar plate body (101). The flow divider (21) separates two vortices with opposite rotation directions in the vortex street and directs one vortex to the edge of the bipolar plate body (101) which is perpendicular to the original vortex direction.

2. The automatic bipolar plate welding equipment according to claim 1, characterized in that: The vortex generating end (2) is a turbulence column, and the turbulence column is airfoil shaped.

3. The automatic bipolar plate welding equipment according to claim 2, characterized in that: The vortex generating end (2) has at least two turbulence columns, which are arranged in an alternating pattern with a spacing of 1.5 times the column diameter.

4. The automatic bipolar plate welding equipment according to claim 3, characterized in that: The flow divider (21) is Y-shaped with a bifurcation angle of 15°. The flow direction of the airflow ejected from the nozzle is a horizontal plane on one side and an arc-shaped wall on the other side.

5. An automatic bipolar plate welding device according to any one of claims 1-4, characterized in that: The bipolar plate body (101) is provided with a flow stabilizing groove (22) on the welding side. The flow stabilizing groove (22) is provided with a groove on the side facing the bipolar plate body (101). The overall length of the flow stabilizing groove (22) is greater than the side of the corresponding bipolar plate body (101).

6. The automatic bipolar plate welding equipment according to claim 5, characterized in that: The groove of the flow stabilizing groove (22) is arc-shaped, and the overall height of the flow stabilizing groove (22) is higher than that of the bipolar plate body (101).

7. The automatic bipolar plate welding equipment according to claim 5, characterized in that: The surface of the groove of the flow stabilizing groove (22) is polished with low roughness.

Images