Weber C.J.,Freudenberg Vliesstoffe SE and Co KG |
Geiger S.,Freudenberg Vliesstoffe SE and Co KG |
Falusi S.,Freudenberg Forschungsdienste SE and Co KG |
Roth M.,Freudenberg Forschungsdienste SE and Co KG
AIP Conference Proceedings | Year: 2014
Separators for Li Ion batteries have a strong impact on cell production, cell performance, life, as well as reliability and safety. The separator market volume is about 500 million m2 mainly based on consumer applications. It is expected to grow strongly over the next decade for mobile and stationary applications using large cells. At present, the market is essentially served by polyolefine membranes. Such membranes have some technological limitations, such as wettability, porosity, penetration resistance, shrinkage and meltdown. The development of a cell failure due to internal short circuit is potentially closely related to separator material properties. Consequently, advanced separators became an intense area of worldwide research and development activity in academia and industry. New separator technologies are being developed especially to address safety and reliability related property improvements. © 2014 AIP Publishing LLC.
Kuhn S.,Freudenberg Forschungsdienste SE and Co. KG |
Unterumsberger F.,Mitsubishi Hitachi Power Systems Europe GmbH
Praktische Metallographie/Practical Metallography | Year: 2014
Generally, the clarification of hydrogen induced component damage cases by means of failure analysis is based on fractographic examinations in combination with hydrogen analyses. However, due to high diffusion rates of hydrogen in steels at RT (room temperature), providing the analytical evidence of an excessive hydrogen content is rarely possible. This work presents potential production and application related hydrogen sources as well as the mechanisms of hydrogen induced delayed formation of cracks and illustrates a systematical approach to produce comparative hydrogen fracturing. Therefore, the damaged component's specific material condition is the basis in order to generate a comparative fracture surface with an identical fracture morphology and applying the same damage mechanism. The approach of producing comparative fracturing is illustrated by two cases of damage.
Schultz F.,Freudenberg Forschungsdienste SE and Co. KG
Gummi, Fasern, Kunststoffe | Year: 2014
The computer tomography (CT) is an efficient method with its main field of application in non-destructive part and material analysis. In the first step of the CT analysis a three dimensional model of a sample is calculated from multiple x-ray pictures. Afterwards this CT model allows the virtual cutting and an analysis of the sample at any possible position.
Kreiselmaier R.,Freudenberg Forschungsdienste SE and Co. KG |
Beck K.,Freudenberg Forschungsdienste SE and Co. KG |
Paimann P.,Freudenberg Forschungsdienste SE and Co. KG |
Priess C.,Freudenberg Forschungsdienste SE and Co. KG |
And 2 more authors.
International Polymer Science and Technology | Year: 2014
Oxidative ageing is one of the important factors limiting the lifetime of elastomer products. The chemical reactions taking place during ageing are very complex as a result of interactions between numerous components of the compound and the reactive intermediates. The chemiluminescence method delivers a good insight into the progress of oxidative ageing reactions. This method detects the light which is emitted during the degradation of hydroperoxides that are formed during the ageing process. Using a mathematical model for the oxidative ageing process it is possible to reproduce the intensity of the chemiluminescence signal as a function of time. By fitting the calculated and the measured curves, the reaction constants used within the model can be determined. The model can be tested and a more exact determination of the reaction constants can be achieved by preparing specific compounds with different amounts of antioxidants, for instance, or by directed variation of the oxygen concentration during the chemiluminescence measurement. This approach delivers a deeper understanding of the oxidative ageing process. Using this model it is possible, for instance, to predict the impact of recipe variations. In this way, elastomer compounds can be optimised still more effectively. In addition, for example, the influence of the oxygen concentration specific to the application can be taken into account when estimating the lifetime of elastomer products. © 2014 Smithers Information Ltd.
Herrlich U.,Freudenberg Forschungsdienste SE and Co. KG |
Komp A.,Freudenberg Forschungsdienste SE and Co. KG
Gummi, Fasern, Kunststoffe | Year: 2013
Both the non-woven as well as the raw material specimens based on spider silk-type proteins were investigated for their suitability as wound dressings. To this effect, degradability investigations due to wound fluid and body enzymes, cytoxicity measurements and wound-healing model tests were performed. In one case a significant improvement in healing progress as opposed to blank tests could be evidenced.