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The production of lithium-ion batteries is characterized by high scrap rates. With material costs of 70-80% of the cell price, these are a significant cost factor. By using AI, correlations of process data and cell properties can be determined and particularly quality-relevant process steps can be identified. However, the prerequisite for the use of AI is a clean collection, description and allocation of data which is very time-consuming. In the BMBF-funded projects “KontElPro”, for solvent-free electrode production and “AgiloBat2”, for the agile production of format-flexible cells, software is being developed to solve this problem. The corresponding software system "Batalyse" is capable of automatically collecting, categorizing, linking and evaluating test, analysis and production data. Quality-relevant parameters of the produced (lab) cells such as capacity, resistance and power can thus be directly correlated with process parameters and data. The complete process chain of input materials, (intermediate) products, sensors, equipment, process parameters and all evaluated result data of the produced cells is stored in the database. All data, correlations and logic is provided by this database via an interface for AI applications. The aim is to use this data to generate digital twins of each individual process step and to optimize them step by step. Later, the processes are to be controlled autonomously by AI applying optimized process parameters to avoid or at least to reduce scrap. In the talk we present the structure, status and use of the software for research data management and in the use of in the research production of Li-ion cells.

Mechanical modifications or harmful side reactions are undesirable ageing effects that can occur during cycling. These phenomena have a negative impact on cell performance and consequently limit cycling stability. The focus here is on investigations of ageing processes such as volume changes and electrolyte decomposition during cycling. Thickness measurements as well as gas analytical studies of Li-C half cells with a carbonate-based electrolyte are presented. Graphite and Hard Carbon, respectively, were used as carbon materials. The electrolyte applied consists of 1M LiPF6 in EC:DMC (1:1, wt). All investigations were carried out using specially developed multifunctional test setups and accordingly modified test cells. Application-oriented analysis such as gas analysis, thickness measurements or both combined are suitable methods to define operating parameter, to benchmark and to identify decomposition reactions.In-operando electrochemical dilatometry was conducted to check whether an irreversible increase in thickness occurred. On the corresponding cell configurations, the dilatation was recorded over the entire electrode stack as well as of the separate working electrode only.Furthermore, in-operando MS could be used to detect gaseous substances produced by (electro)chemical processes as a function of the state of charge. With the GC-MS, a post-mortem analysis could be performed to identify the individual substances qualitatively. Results of the different half cells are shown and can be compared with each other. A detailed relationship can be demonstrated between the change in thickness and the potential curve. Moreover, any emerging Li-plating is clearly detectable. Among others, carbon dioxide, ethane as well as ethene were identified as degradation products of the carbonate-based electrolyte and are formed during the charging process. In addition, possible correlations between gas evolution and thickness changes can be shown. These analytical studies make an important contribution to get a more detailed insight into ageing processes that take place. The possible combination of in-operando dilatometry with in-operando mass spectrometry opens up new interesting perspectives to analyse cell performance. Finally, the shown results lead to a better understanding and help to develop appropriate countermeasures in order to reduce the negative effects and thus to ensure a higher cycling stability. This work is supported by the Fraunhofer and Max Planck cooperation program (Germany) in the project “ClusterBatt” with Fraunhofer Institute for Material and Beam Technology IWS, Dresden and Max Planck Institute of Colloids and Interfaces MPIKG, Potsdam. Figure 1

Li-S cells can have high gravimetric energy densities above 300 Wh kg−1 when the electrodes and cell components are optimized. Low electrolyte/sulfur mass ratios or more generallly, the relative amount of electrolyte in a Li-S cell have an especially high impact on the achievable gravimetric energy density. A negative side effect of low electrolyte/sulfur ratios are low cycle numbers due to electrolyte decomposition and the possibility that electrolyte becomes inaccessible at the lithium metal anode when the lithium becomes more and more porous during cycling. Electrode thickness measurements were performed during cycling for various cell chemistries such as lithium-sulfur (Li-S) with different cathode sulfur loadings and porosities, lithium-hard carbon (Li-HC), lithium-silicon (Li-Si), prelithiated HC-sulfur (LiHC-S), prelithiated Si-sulfur (LiSi-S) and Li-ion. The thickness measurements provided information about mechanical stress and irreversible thickness changes. The thickness measurements also helped to explain different electrolyte decomposition behavior and they can be used to discuss the impact of thickness changes on gas analysis. The electrolyte decomposition of the Li-S standard electrolyte based on lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in dimethoxyethane (DME): dioxolane (DIOX) with LiNO3 was examined by online mass spectrometry (MS) within Li-S, Li-HC, Li-Si, LiSi-S and LiHC-S cells. Several electrolyte decomposition products were verified by post-mortem gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) of Li-S cells with cycled electrolyte.

Cast start situations for rolling ingot DC casting can represent severe risks for cast shop workers due to unforeseen development of butt curl of individual ingots. Hydro’s R&D center Bonn has the ambition to provide procedures and related tools helping to preventing these risks. In order to react on the critical development of butt curl of individual ingots in a casting unit a monitoring of relative motion of the bottom side of the solidifying ingot to the starter block is required. This means a continuous distance measurement under extremely harsh conditions. Possible solutions must be watertight, heat resistant, need wireless data transmission capabilities and implementation and preparation of the system have to be user-friendly. Current status of the development includes real-time visualization and data storage in the process control system. This paper describes the technological approach, the testing under plant conditions and application examples of the system.

In-operando Raman spectroscopy with high spatial resolution (1 µm2) was employed to study the lithium deposition reaction on graphite electrodes. The 1850 cm−1 acetylide band, which is always found on lithium metal spectra, appeared right after reaching the full lithiation of graphite, when the G and D bands of graphite vanished. The band was observed during potestiostatic overcharge at high and low current rates and in a post-mortem analysis. The results suggest that during the constant voltage step, lithium is deposited and concurrently chemically intercalated into graphite. The second mechanism becomes the dominant after 30 min, when the current decreases. The evolution of the G and D bands of graphite and the lithium concentration in the electrolyte was also studied. The results suggest that EC is slowly consumed after the onset of lithium plating. This work demonstrates the possibility of studying locally the lithium plating onset and chemical intercalation on the graphite electrodes in real time.

As more and more applications require high energy density electrochemical storage systems that deliver more than 200 Wh/kg, Lithium-ion batteries with silicon-based anodes provide promising electrochemical properties especially high specific capacity. In this paper, we present micro-grain structured silicon deposited by DC sputtering on special copper foil that serves as current collector. It is demonstrated that high-density silicon anodes are obtained with more than 2000 mAh g−1 and 2.0 mAh cm−2 that can be considered as a commercial value. In addition, irreversible capacity during the first galvanostatic cycle can be lower than 20% for such anodes. Finally, it is found that there exists a clear correlation between the grain-size and the texture of the amorphous silicon to the electrochemical performance of half-cells.

Målet med denne studien var å se nærmere på trener-utøver relasjonen, et underutviklet felt innen idrettspsykologisk forskning (Yang & Jowett, 2016), og hvilken betydning denne relasjonen har for utøvers utvikling. Jowetts «3Cs» (Jowett & Meek, 2000; Jowett & Ntoumanis, 2004) ble brukt som teoretisk rammeverk. Videre ble det postulert, med bakgrunn i teori, at en potensiell positiv sammenheng kunne være påvirket av utøvers evne til å selvregulere læring. Dette er en spørreskjemabasert tverrsnittundersøkelse av ungdomsfotballag på regionalt og nasjonalt nivå. Utvalget bestod av 47 mannlige fotballspillere i alderen 14-19 år (M = 16,5, SD = 1,41), fra 3 forskjellige lag, og 3 trenere, tilhørende hvert av lagene, fra 24-47 år (M = 38,9, SD = 10,5). Trener-utøver relasjonen ble testet med to forskjellige utgaver av nCART-Q (Caspersen, 2007), én utøver- og én trenerutgave. Selvregulering av læring ble testet med et fotballspesifikt skjema av Toering, Jordet og Ripegutu (2013). Spillerens utvikling siste år er vurdert av spillerens trener, på en skala fra 1-10. Av resultatene ser det ut til å være en sammenheng mellom treners følelse av «closeness» overfor utøveren og utøvers utvikling det siste året (rs = ,409, p < ,01). Det diskuteres om dette er på grunn av Pygmalion-effekten (Rosenthal og Jacobson, 1968), om det er fordi trenere liker spillere som har utviklet seg mer bedre enn andre spillere, eller om det er på grunn av glorie-effekten (Cooper, 1981). Det fantes ingen medierende effekt av selvregulering av læring mellom relasjonen og utvikling i denne studien. Dog finner vi allikevel svake til moderate positiv korrelasjoner mellom utøvers følelse av «closeness» og selvreguleringsprosessene planlegging (rs = ,304, p < ,05) og evaluering (rs = ,345, p < ,05). Disse sammenhengene har aldri tidligere vært påvist i en idrettslig kontekst og bør således forfølges videre, da de kan være med på å utvide vår forståelse av hvilken betydning signifikante andre har for selvregulering av læring. Denne studien er den første der disse idéene kobles og verktøyene brukes på denne måten. Derfor bør studien anses som en slags pilotstudie og resultatene tolkes på denne måten. Avslutningsvis legges det fram metodiske begrensninger, forslag til fremtidig forskning og praktiske implikasjoner.

Supercapacitors are usually used as energy storage devices that work at a high current rate. This operating mode is often accompanied by the production of large amounts of heat inside the cell. Therefore, health monitoring of supercapacitors is still needed to avoid overheating and subsequent destruction. This paper presents a new method to determine the heat generation and the resulting temperature development of an aqueous hybrid capacitor based on extensive measurement data. We concentrate not only on the Ohmic power loss but also on heat phenomenon originating from side and overcharge reactions as well as entropy effects. The bearing of the final state of charge and the charging current on the temperature development is demonstrated. Finally, the temperature parameters of air and water cooled capacitors are simulated. The temperature distribution within the cell as a function of time is presented and discussed. The great advantage of the developed evaluation method is that it is an inexpensive method which can be realised in most test laboratories and that the measurements and simulations consider all crucial origins of power loss. The results obtained can be used to evaluate appropriate cooling systems. The method can be applied to capacitors and batteries.

Li-S cells are attractive due to their high potential gravimetric energy density, but they achieve only low cycle numbers. A major reason for this is a continuous electrolyte decomposition during cycling. As low electrolyte/sulfur ratios are required for high gravimetric energy density, this electrolyte decomposition reduces the obtainable cycle number to below 50. It is therefore extremely important to evaluate, reduce or ideally prevent this electrolyte decomposition by utilizing new electrolyte (additives), separators and protection layers. Applying in-situ mass spectroscopy, the electrolyte decomposition has been characterized for Li-S cells with lithium metal anode, silicon anode and carbon anode with various electrolyte compositions, electrodes and cycling parameters. Electrolyte cracking leads to gaseous substances, some of which are created continuously while others show a maximum depending on the state of charge. Standard ether-based Li-S electrolytes (e.g. DME:DIOX) are unstable with Li metal anodes and will always limit the obtainable cycle number unless further protection devices are applied. The attached figure demonstrates specific gaseous substances created in a Li-S cell during cycling between 1.8-2.6 V at 0.6 mA/cm². Figure 1

It is well known that silicon presents one of the most important anode materials for the improvement of lithium-ion cells in terms of energy density. Indeed, silicon’s high theoretical specific capacity to lithium (more than 3800 mAh/g at room temperature), environmental friendliness, low potential compared to lithium and material abundance turns silicon to a strong candidate for the replacement of carbon-based anodes [1]. However, one of the main drawbacks of silicon’s application to the lithium-ion technology is its poor electrochemical cycling stability over several galvanostatic cycles, mainly due to silicon’s huge volume change (around 300%) during lithiation and delithiation that lead to high internal mechanical stress [2]. Many alternatives have been proposed that alleviate this mechanical expansion through the use of nanostructured silicon sometimes combined with carbon-based materials [3]. However, most of proposed solutions are technically and financially demanding at least for production. In this presentation, we investigate the physical and the electrochemical properties of micro-grain structured silicon deposited on special copper with nodular grains. Silicon films with high loadings (0.8-1 mg/cm2) have been deposited with the aid of DC sputtering technique on top of copper foil with nodular grains. Half-cells with silicon as anode and Lithium metal as counter electrode were prepared. The gravimetric specific capacity was estimated by measuring the weight of silicon. Scanning Electron Analysis (SEM) has been performed in order to investigate the physical properties of the deposited material. Figure 1 demonstrates the SEM picture of the micro-grain structure of silicon when deposited on the copper foil with nodular grains. It is shown that silicon is organized in columnar form with grains of an average size of 1-2 μm. By KaptonTM tape tests, the adhesion of this material on the copper foil was found to be excellent. The equivalent silicon thickness that has been grown is estimated to be more than 4 μm (loading 0.8-1 mg/cm2). Figure 2 shows the electrochemical behavior of such half-cells when cycled with current of 0.6 mAh/cm2 (C/3 rate). Concerning the specific capacity, we observe a slight decrease from 2200 mAh/g to 1800 mAh/g and after the 5th cycle, an increase up to the initial value. It is also mentioned that the silicon anode achieves high specific areal capacity up to 2 mAh/cm2. According to McDowell at al. [4], amorphous silicon spheres with diameter of around 1 μm do not fracture upon lithiation and therefore anodes fabricated with such material demonstrate stable capacity over galvanostatic cycling. Thus, our experimental results further support that the DC sputtered amorphous spheres provide excellent capacity retention and good stability. Acknowledgement This work is supported by European Regional Development Fund and National Funds/German-Greek Bilateral R&D Cooperation Initiative/2013-2015. References [1] C. John Wen, Robert A. Huggins, Journal of Solid State Chemistry, 37, 271-278 (1981) [2] Candace K. Chan, Hailin Peng, Gao Liu, Kevin McIlwrath, Xiao Feng Zhang, Robert A. Huggins and Yi Cui, Nature Nanotechnology 3, 31 - 35 (2008) [3] Tae Hoon Hwang, Yong Min Lee, Byung-Seon Kong, Jin-Seok Seo, and Jang Wook Choi Nano Letters 12, 802-807 (2012) [4] Matthew T. McDowell, Seok Woo Lee, Justin T. Harris, Brian A. Korgel, Chongmin Wang, William D. Nix, and Yi Cui Nano Letters 13, 758-764 (2013) Figure 1