Hydrogen Fuel Cell Laser Welding Revealed

The biggest advantage of hydrogen fuel cell technology is its high range and fast hydrogen refueling, and hydrogen is needed by industries such as steel, chemical, aviation, etc. In the future, hydrogen fuel cells will not only cover passenger cars and commercial vehicles, but also application scenarios such as unmanned aerial vehicles, ships, rail transportation, and electric motors for power generation.


Typically a single fuel cell cell produces less than 1 volt, so many fuel cell cells need to be stacked side-by-side to get enough volts in an application. Therefore, the fuel cell consists of several small cells, each of which consists of bipolar plates and MEA as the main components, which are formed by laser welding the cathode and anode plates together.

 

Hydrogen fuel cell welding is a very time-consuming process, and completely sealed welding is a basic requirement. Low-quality welding can seriously affect the working performance and service life of the fuel cell and even lead to hydrogen or other liquid leakage. Optimizing the welding process can greatly reduce the cost of hydrogen fuel cell production.

Laser welding of metal bipolar plates

The main roles of the bipolar plate (abbreviated as BPP) are to support the MEA, to provide hydrogen, oxygen, and coolant fluid pathways and to separate the hydrogen and oxygen, to collect electrons, and to conduct heat. Common materials for BPPs are graphite, composites, and metals. Metal materials have high mechanical strength, the excellent electrical and thermal conductivity of the body phase, easy-to-make thin plates, and stamping processing molding characteristics, its application is the most widely used.

 

The metal bipolar plate is made of two metal monopole plates sealed and welded by stamping, and the most commonly used materials are titanium alloy and stainless steel 316L. After stamping, the hard force of the material gathers in the interior and is released when welding, which is prone to deformation of the plate, weld-through of the runners, poor sealing, etc. At the same time, laser welding of metal bipolar plates will cause localized generation of metal oxide, which will affect the surface coating performance of the area. At the same time, the laser welding of metal bipolar plates will cause the generation of local metal oxides, which will affect the surface coating performance in the region, and ultimately affect the performance and life of the fuel cell.

 

To solve the above problems, based on the accumulation of technology and processes in the past, MRJ-laser has eliminated the deformation and other problems by welding in the flow channel area (bipolar plate flow field with dotted flow field, parallel DC flow field, intersecting finger-shaped flow field, and single-channel serpentine flow field, etc.), ensured the hermetic sealing between the two monopole plates, and minimized the deformation of the ultra-thin plate as low as 0.05mm, to effectively control the welding deformation of the whole hydrogen fuel cell stack. The welding deformation of the entire hydrogen fuel cell stack is effectively controlled while improving the electrical conductivity of the metal bipolar plate.

 

Hydrogen fuel cell bipolar plate welding line

 

Process flow: robot loading pallet - front and back side inspection - automatic code scanning - fixture positioning and pressing - automatic welding - gas-tightness inspection - marking - discharging.

 

At the same time as high-speed continuous welding, it realizes the latest structure of metal bi-electrode plate precision welding without deformation, ultra-long weld path, narrow and uniform weld seam, and excellent welding air tightness.

 

How to improve the welding beat and reduce the welding of the residual height, so that the rest of the height is as small as possible is becoming a new challenge facing the industry, to improve the stability of the product and market competitiveness, Lianyin laser-based on the existing technology, to carry out the development of their own fixtures, etc., to achieve the residual height of less than 10um, and the welding efficiency is increased to 400mm / s or even to 1,000mm / s, to ensure that the welding process is highly efficient and stable.

Laser Welding of Electric Stack Ties

The fuel cell stack is mainly composed of seven parts: end plate, insulating plate, current collector plate, bipolar plate, membrane electrode, fasteners, and seals. After stacking the small unit components of the stack into sub-pieces, the stack is pre-assembled and then pressed, then tensioned using tie-wraps, and the tensioned tie-wraps are welded and fixed by laser welding, which in turn achieves a stabilizing effect.

 

Both graphite and metal electrostacks can be fixed by screw fixing or laser welding of the tensioned ties after the compression process. Traditionally, metal and graphite stacks are fixed with screws, but with the urgent demand for "lightweight" development of stacks, many stacks industry enterprises are gradually using laser welding to replace screw fixing and laser welding is considered as the mainstream way of tensioning in the future.

 

For the laser welding of power stacks, MRJ-laser has developed special lasers and welding oscillating heads, and at the same time, to meet the market demand, it has also developed a variety of configurations adapted to different types of power stack tie welding, such as single-mode lasers, multi-mode lasers, and ring lasers; single-fiber injection head, single-fiber oscillating welding head, and vibrating mirror welding head configurations.

 

MRJ-laser electric pile tie welding program, to ensure that the welding tension meets the customer greater than 10KN tension, the welding material thickness can be compatible with 0.5-2mm tie; and the weld seam is neat and beautiful, tensile strength test in the base material fracture, weld seam shape is complete, weld the back of the weld seam can not be welded through.

 

Fully automatic intelligent hydrogen fuel cell stack assembly line

 

Process flow: raw material scanning - automatic stacking - pressurization - bundling and fixing - gas tightness test - output electric stack - test

 

The whole line is equipped with multi-channel airtightness test, sub-stack assembly test, stack assembly inspection, bare stack inspection, screening of non-conforming products, greatly improving the production through rate, reducing the frequency of manual rework, each airtightness test data records and can be reviewed, including the traceability of non-conforming product test information, flexible production line with one-key switching function, select any product formula can be switched to production.

Comments

Post a Comment

Popular posts from this blog

Carbon fiber fuselage with 8m seams can be CO2 laser welded

Image
European researchers  say they have successfully welded two halves of an 8-meter-long fuselage made of carbon-reinforced fibers with a CO2 laser. This means that ultralight passenger aircraft can be manufactured using this method.   The demonstration, completed by a large international consortium led by Airbus and comprising several Fraunhofer institutes, provides proof of concept for the chipless connection of carbon fiber-reinforced thermoplastic (CFRTP) component structures with a CO2 laser. Dynamic Beam Shaping Working under the Multifunctional Fuselage Demonstrator (MFFD) project, which is part of the EU's wider Clean Skies 2 research program, the team at the Fraunhofer Institute for Materials and Beam Technology (IWS) in Dresden says the novel construction method and process will significantly reduce weight, material and time. The novel construction method and process will significantly reduce weight, material, and time.   They used a CO2 source to weld long seams ...
Read more

High-speed laser cladding technology enables laser additive manufacturing

Image
In the wave of rapid development of science and technology, laser technology has become the core driving force of advanced manufacturing industry, profoundly reshaping the production pattern of various industries. Among them, high-speed laser cladding technology has become the key technology in the field of material surface modification and repair by virtue of its significant advantages, and has attracted much attention. In this scientific and technological competition, ZKZM  has stood out from the crowd by virtue of its profound scientific research background and unremitting technological attack, and has become the backbone of leading the technological development of the laser additive manufacturing industry. High-speed laser cladding technology uses a high-energy density laser beam as the heat source to accurately clad special metal alloy powder on the surface of the metal substrate. Under the action of laser energy, the powder is rapidly melted and solidified, forming a metallu...
Read more

5 Solutions for Laser Welding Defects

Image
With the development of industrial manufacturing in the direction of high-end, intelligent, green, new energy vehicles, lithium batteries, semiconductors, and emerging markets demand-driven, the demand for laser welding has been continuously stimulated, the scope of application and the market continues to expand. Especially in the fields of consumer electronics, new energy vehicles, and other fields, the requirements for laser welding are becoming more and more high, providing a huge market space for laser welding. However, any processing method without a good grasp of its principles and processes will produce certain defects or defective products, laser welding is no exception. Only a good understanding of these defects, and learning how to avoid producing these defects, in order to better utilize the value of laser welding, processing the appearance of fine, high-quality products. MAX  welding application engineers through the accumulation of long-term experience, summed up some ...
Read more