• Energy Research

Lithium‐ion battery (LIB) cells of the 18650 format are built in‐house with different amounts of an electrolyte. After wetting and prior to subsequent formation, the cells are opened. The electrolyte is regained by centrifuging the entire jelly roll and quantified by a gas chromatography‐flame ionization detector (GC‐FID) and inductively coupled plasma‐optical emission spectroscopy (ICP‐OES). The influence of a filling protocol applying cycles with over‐ and reduced pressure is examined with a focus on the electrolyte composition. No significant difference is found in the ratio of linear (LC) to cyclic carbonates (CCs). Furthermore, extraction by centrifugation is investigated in different scenarios by simulating almost “dry” cells to minimize alterations during the sample preparation. The quantification of these electrolytes indicates a slightly reduced amount of LC in the sample.

Abstract Cost-efficient battery cell manufacturing is a topic of intense discussion in both industry and academia, as battery costs are crucial for the market success of electrical vehicles (EVs). Based on forecasted EV growth rates, battery cell manufacturers are investing billions of dollars in new battery cell plants. Whether these billion-dollar investments are economically viable depends on the materialization of forecasted EV growth rates and company-specific competitive market positions. For both, cost-efficient battery cell manufacturing is key for success. To ensure cost-efficient battery cell manufacturing, transparency is necessary regarding overall manufacturing costs, their cost drivers, and the monetary value of potential cost reductions. Driven by these requirements, a cost model for a large-scale battery cell factory is developed. The model relies on the process-based cost modelling technique (PBCM) and includes more than 250 parameters. Based on this cost model, directions are provided, how minimum costs can be achieved reflecting current and future state of technology. Further, it is outlined which process steps and cost elements have the greatest impact on total cost and should thus be focused within future cost reduction activities.

Perspective on recent improvements in experiment and theory towards realizing lithium metal electrodes with liquid electrolytes.

AbstractInvestigations on the effect of flame retardant additives (FRs) on the abuse tolerance of large scale lithium ion battery (LIB) cells (5 Ah) are of high relevance in battery science and industry but rarely performed as they are cost and time consuming. In addition, even though FRs are frequently investigated, their positive effect on the safety properties of larger full LIB cells under abusive condition has not been proven yet. The promising FR (phenoxy) pentafluorocyclotriphosphazene (FPPN) is known to exhibit excellent flame retardant‐ and electrochemical properties at the same time. Therefore, FPPN is investigated towards abuse tolerance in 5 Ah LIB cells in this study. Calorimetric investigations show that a mass percentage of 5 wt % FPPN mixed to a standard electrolyte, significantly reduces the self‐heating rate of 5 Ah cells in the temperature range from 80 °C to 110 °C. While nail penetration and external short circuit experiments provide no significant difference between standard and FPPN‐containing cells, an increased overcharge tolerance and a favorable thermal stability at ≈120 °C in overcharge and oven experiments could be shown.

A comprehensive review article addressing the prospects of thein situpolymerization strategy as a tool for surpassing the challenges of electrode|electrolyte interfaces & interphases in lithium polymer batteries.

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In this work, the properties of silver-modified LiMn2O4 cathode materials are revisited. We study the influence of calcination atmosphere on the properties of the Ag-coated LiMn2O4 (Ag/LMO) and highlight the silver oxidation. The effect of the heat treatment in vacuum is compared with that in air by the characterization of the structure, specific surface area, Li transport properties and electrochemical performance of Ag/LMO composites. Surface analyses (XPS and Raman spectroscopy) show that the nature of the coating (~3 wt.%) differs with the calcination atmosphere: Ag/LMO(v) calcined in vacuum displays Ag nanospheres and minor AgO content on its surface (specific surface area of 4.1 m2 g−1), while Ag/LMO(a) treated in air is mainly covered by the AgO insulating phase (specific surface area of 0.6 m2 g−1). Electrochemical experiments emphasize that ~3 wt.% Ag coating is effective to minimize the drawbacks of the spinel LiMn2O4 (Mn dissolution, cycling instability, etc.). The Ag/LMO(v) electrode shows high capacity retention, good cyclability at C/2 rate and capacity fade of 0.06% per cycle (in 60 cycles).