The recent development of individual mobility is characterized by a resource‐saving and environmentally friendly technology policy. Electromobility has the greatest potential to meet these demands. Due to the high volumetric power density at both the cell as well as the battery levels, pouch cells are addressed as a target cell format. As a separation of the electrodes is absolutely necessary for this cell design, the separation of the electrodes constitutes a basic operation of the pouch cell production. The established separation methods, such as die and laser cutting, are compared in this work with regard to their physical cutting‐edge quality. For reproducible evaluation, the occurring cutting‐edge characteristics are defined to clearly describe the quality of the separated electrode. Furthermore, the influence of the photonically and mechanically produced cutting edge on the electrochemical performance is presented. The results show that the delamination of the active materials and the bending of the collector and the metal spatter have the greatest influence on the electrochemical performance of the cell.

Due to the increasing demand for high-performance cells for mobile applications, the standards of the performance of active materials and the efficiency of cell production strategies are rising. One promising cell technology to fulfill the increasing requirements for actual and future applications are all solid-state batteries with pure lithium metal on the anode side. The outstanding electrochemical material advantages of lithium, with its high theoretical capacity of 3860 mAh/g and low density of 0.534 g/cm3, can only be taken advantage of in all solid-state batteries, since, in conventional liquid electrochemical systems, the lithium dissolves with each discharging cycle. Apart from the current low stability of all solid-state separators, challenges lie in the general processing, as well as the handling and separation, of lithium metal foils. Unfortunately, lithium metal anodes cannot be separated by conventional die cutting processes in large quantities. Due to its adhesive properties and toughness, mechanical cutting tools require intensive cleaning after each cut. The presented experiments show that remote laser cutting, as a contactless and wear-free method, has the potential to separate anodes in large numbers with high-quality cutting edges.

Laser cutting is a promising technology for the singulation of conventional and advanced electrodes for lithium-ion batteries. Even though the continuous development of laser sources, beam guiding, and handling systems enable industrial relevant high cycle times, there are still uncertainties regarding the influence of, for this process, typical cutting edge characteristics on the electrochemical performance. To investigate this issue, conventional anodes and cathodes were cut by a pulsed fiber laser with a central emission wavelength of 1059–1065 nm and a pulse duration of 240 ns. Based on investigations considering the pulse repetition frequency, cutting speed, and line energy, a cell setup of anodes and cathodes with different cutting edge characteristics were selected. The experiments on 9 Ah pouch cells demonstrated that the cutting edge of the cathode had a greater impact on the electrochemical performance than the cutting edge of the anode. Furthermore, the results pointed out that on the cathode side, the contamination through metal spatters, generated by the laser current collector interaction, had the largest impact on the electrochemical performance.

A new self-organization phenomenon was observed during pulse current electrodeposition of nickel layers from an acidic sulfamate electrolyte containing a few 100 mg/l of a polymeric surfactant. Scanning electron microscopy (SEM) analysis reveals ordered arrays of nanometer sized pits. Within domain of about 1 μm size the pits arrange on a hexagonal lattice with a pore-to-pore spacing of about 120 nm. SEM inspection of cross sections show that the pits are the ends of straight nanochannels of about 40 nm diameter, extending virtually through the complete layer parallel to the growth direction. The additive is an amphiphilic polymer consisting of a backbone carrying carboxylate groups, styrene units and polyether side chains. According to current knowledge the presence of this polymer in the electrolyte and the application of special current pulse patterns are preconditions for the formation of the ordered nanopore arrays. The mechanism responsible for this kind of self-organization is still a matter of speculation but experimental results point to hydrogen nanobubbles acting as templating agents.

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531 2155 900 Web: www.tu-braunschweig. de/iot In this study, we report on a simple and versatile method for PEGylation of surfaces which is applicable practically independent of the substrate material: a poly(acrylic acid)graft-poly(ethylene glycol) (PAA-g-PEG) copolymer was synthesized with grafting ratios g in the range of g ¼ 20-2 [acrylic acid (AA) monomers to PEG side chains] and adsorbed either on bare stainless steel or on stainless steel precoated with different types of polyelectrolyte multilayers (PEMs) from aqueous solution. For PAA-g-PEG synthesis two principal routes were compared with respect to yield and control of g: the active ester route using different carbodiimide coupling agents and the route via poly(acrylic acid chloride) (PAA-Cl).Measurements based on Fourier transform infrared spectroscopy in attenuated total reflection mode (FTIR-ATR) showed that the adsorbed amount of PAA-g-PEG copolymer is in general drastically enhanced, compared to bare stainless steel as a substrate, when a suitable PEM is used as an interlayer. The amount was also found to be strongly dependent on the type of PEM and to increase with increasing thickness of the PEM interlayer. The stability of highly PEGylated PEMs and the influence of thermal crosslinking on stability were investigated by immersing the PEM-PEG samples for 1 week into 1 M NaCl solution at pH 4.5 and 0.15 M phosphate buffered saline (PBS) at pH 7.4, respectively.

Duplex stainless steel is common in thick-walled components such as longitudinal welded pipes in the oil and gas industries and as parts of various machines in the chemical and food industries. Electron beam welding is a very suitable method for welding such components. Due to the high power density of the electron beam combined with the decreased evaporation temperature in a vacuum atmosphere, steel with a sheet thickness of up to 150 mm can be welded in one pass. In the case of the electron beam welding of duplex stainless steels, vacuum atmosphere in the working chamber causes a nitrogen effusion from the weld pool. The microstructure of the resulting weld is characterized by an unacceptable high ferrite content, which is the main reason for both low impact toughness and low pitting corrosion resistance. This work focuses on the influence of nitrided weld edge surfaces on metallurgical properties of the resulting welded joint. The aim here is to investigate the effect of increased nitrogen content at the weld edges on nitrogen loss during EB-welding. The welds produced within the experimental work were characterized by means of microstructural analysis and the use of optical and energy dispersive X-ray spectroscopy. It was shown that nitrided weld edge surfaces can compensate nitrogen loss from the weld pool and decrease the ferrite content in the resulting weld.