11:15am - 11:30am
Improved thermal joining of aluminum and aluminum-polymer composites for battery applications through laser surface structuring
Institute for Machine Tools and Industrial Management (iwb), Technical University of Munich, Boltzmannstr. 15, 85748 Garching, Germany
Lithium-ion batteries are the main electrochemical energy storage solution for electromobility applications because of their advantageous characteristics compared to other battery technologies. Currently, three cell designs (prismatic hardcase, prismatic pouch and cylindrical cells) with specific advantages and disadvantages are present in the market. Novel cell concepts aim to combine the strengths. For example, the good mechanical stability of hardcase cells should be merged with the high gravimetric energy density of pouch cells. Therefore, a laser structuring process is presented, which significantly improves the adhesion between aluminum-polymer composite foils and solid aluminum during thermal joining. Microscopic structures were formed on the aluminum surface by nano-second laser pulses. The results of a laser parameter study were analyzed by optical means (laser scanning microscopy and scanning electron microscopy) and in terms of adhesion strengths between the components. In conclusion, strategies and recommendations for the laser structuring process are derived.
11:30am - 11:45am
Laser-assisted selective fabrication of copper traces on polymers by electroplating
1Center for Physical Sciences and Technology, Department of Laser Technologies, Vilnius, Lithuania; 2Center for Physical Sciences and Technology, Department of Chemical Engineering and Technology, Vilnius, Lithuania
The paper reports a facile and low-cost laser-assisted method for selective deposition of copper traces on polymer surfaces. The technique uses a laser for selective polymer surface modification. The electrical conductivity of some polymers could be increased due to laser irradiation. Kapton PI film was used in our experiment. Samples were patterned using a picosecond laser at 1064 nm wavelength. The experiments were performed using average powers ranging from 4 to 8.5 W in 0.5 W increments, pulse repetition rates from 10 to 100 kHz and a constant scan rate of 100 mm/s. The sheet resistance was measured using the four-probe method, and it was reduced to < 50 Ω per square after laser patterning. Afterwards, the modified surface was metal deposited by electroplating.
Selective deposition of copper on polymers could be used in flexible electronic devices. This technology shows a huge potential in many fields: consumable electronics, automotive, etc.
11:45am - 12:00pm
Manufacturing of functional surfaces by replicating glass moulds structured by multiphoton polymerization
AIMEN Technology Centre, Spain
The present work deals with the fabrication of very low aspect ratio microstructures generated by Multi-Photon Polymerization (MPP) on glass substrates for their further use as good quality and high resolution replication moulds for optoelectronic devices. A commercial UV-curable resin from the ORMOCER® family was employed for the fabrication of the polymeric microstructures on two different substrates: glass and sapphire. These microstructures were replicated by injection moulding on polymeric components with an area of several cm2. The results of this work indicate that high resolution moulds can be fabricated through MPP, favouring the fabrication of high-quality replications. Additionally, the microstructures are proven to be resistant to their use through multiple replications. In fact, the topographical characterizations of the first and last replicas show similar characteristics, proving the reliability MPP for the fabrication of high quality moulds.
12:00pm - 12:15pm
Improved catalytic activity and surface functionalization of nanoparticles by pulsed laser-post processing of colloids.
University of Duisburg-Essen, Germany
The presented talk intends to cover advances in laser-based post-processing of colloidal nanoparticles by laser fragmentation and -defect engineering for catalyst development. First, a new setup which provides a 100 µm thick flat liquid jet for laser post-processing of nanoparticles and favors a 10 times lower laser intensity deviation compared to the conventional cylindrical liquid jet will be presented. Due to the uniform laser intensity in the flat liquid jet, colloidal 3 nm gold nanoparticles with narrow size distribution (PDI < 0.1) were gained. In the second part of the talk, recent advances on laser-based defect engineering and related surface functionalization will be presented at the example of cobalt-spinel-based catalysts. It will be shown, that the catalytic activity is significantly improved especially when less than 3 laser pulses are employed per nanoparticle. In this context, laser-based surface doping and favorable process scalability will be discussed.
12:15pm - 12:30pm
Metallic surface functionalization by femtosecond laser beam shaping and LIPSS for industrial applications
Literature demonstrated the advantages of surface nanoscale texturation in many industrial applications, including batteries, medical implants and linear encoders. The next step is to find a cost-effective and non-invasive solution to replace actual material deposition and tooling techniques at industrial scale.
In the scope of the LASER4SURF project, we developed a new automated workstation enabling fast texturing of large surface samples (i.e. A4 format), using state of the art beam shaping techniques involving DOE and SLM combined with LIPSS generation to increase functionalization performances of the textured materials.
A key part of the workstation is its ability to automatically determine optimal laser processing parameters based on preliminary study done on any other laser processing device.
We also demonstrate that LIPSS texturation increases battery collectors charging capabilities, as well as their lifetime. We also demonstrate better bio-integration of medical implant for the human body, as well as increased accuracy linear encoders.