Improvement of life-time is an important issue in the development Li-ion batteries. Aging mechanisms limiting can efficiently be characterized by physico-chemical analysis aged cells with a variety complementary methods. This study reviews state-of-the-art literature on Post-Mortem cells, including disassembly methodology as well characterization methods for battery materials. A detailed scheme deduced from literature, pre-inspection, conditions and safe environment separation...

The standard format for cylindrical Li-ion cells is about to change from 18650-type (18mm diameter, 65mm height) 21700-type (21mm 70mm height). We investigated the properties of five 18650 cells, three first commercially available 21700, and types similar 20700 in detail. In particular, (i) specific energy/energy density electrode thickness, (ii) area cell resistance, (iii) energy as a function discharge C-rate, well (iv) heating behavior due current flow are analyzed. Finally, production...

We present an extensive analysis of Li-ion battery ageing via Arrhenius plots. The V-shaped plots show minima at optimum temperature corresponding to the longest cycle-life. V-shape signifies crossover between two dominating mechanisms – solid electrolyte interphase (SEI) growth in high range and lithium deposition low range. Subjects our investigations are commercial 5 Ah energy 21,700-type cells with LiNi0.90Co0.05Al0.05O2 + LiNiO2 (NCA LNO) cathode Si/graphite anode (∼3% Si) 0.1 lab-made...

Operation temperature is known to be one of the most impacting parameters for aging Li-ion batteries under cycling conditions. While Li plating usually dominates at low temperatures, Solid-Electrolyte-Interphase (SEI) growth often elevated temperatures. The longest cycle life observed crossover both mechanisms around 25 °C. We introduce color maps show changes in rate during battery aging. Reconstructed 3-electrode full cells with reference electrode that prolonged CV phase charging...

Deposition of metallic Li is a severe aging mechanism in Lithium-ion cells. This study evaluates the influence main operating parameters leading to deposition Li: temperature, charging C-rate, and end-of-charge voltage. Therefore both, graphite anodes NMC cathodes from commercial 16Ah pouch cells are reconstructed into 3-electrode full The position reference electrode between anode cathode allows acquiring potentials vs. (Li/Li+). Extensive evaluations data reveal critical combinations avoid...

Cycling at different C-rates, as well storage aging is performed with five types of commercial 18650-type Lithium-ion cells. X-ray computed tomography measurements show strong deformations the inner part jelly rolls for three cell without center pin after cycling rates in range 3.6–16.6C. For cells cycled 1C, this deformation less pronounced, whereas it totally absent stored The consequence on capacity loss was investigated by Post-Mortem analysis unrolled electrodes, scanning electron...

During charging at low temperatures, metallic Lithium can be deposited on the surface of graphite anodes Li-ion cells. This Li plating does not only lead to fast capacity fade, it also impair safety behavior. The present study observes effect rest periods between and subsequent accelerated rate calorimetry (ARC) tests. As an example, commercial 3.25 Ah 18650-type cells with NCA cathodes are cycled 0 °C provoke plating. It is found that period 25 ARC tests has a significant influence onset...

The study observes thermal behavior of six Lithium-ion batteries with different cell designs. In operando temperature measurements are conducted using a thermographic camera as well internal and external sensors. investigated designs include pouch cells two high-power high-energy 18650 battery types. It is found for all that maximum temperatures the correlate linearly discharge current. This trend explained by basic physical laws. High-power show significant differences, which electrode...

Li-ion cells of the classic 18650 format are directly compared with new 21700 regarding electrochemical, thermal, and geometrical properties. Both types were reproducibly built on pilot scale same electrodes, separator, electrolyte allowing a direct comparison for first time. Internal temperature sensors give insights heating behaviour. Similarities found in voltage curves capacity fade at 1C cycling 25 °C. The energy increase per cell is ~50% from to discharge range 0.5C–3.75C. results...

Li-ion cells are used in a variety of mobile and stationary applications. Their use must be safe under all conditions, even for aged second-life In the present study, different aging mechanisms taken into account accelerating rate calorimetry (ARC) tests. 18650-type cycled at 0°C (Li plating expected) 45°C (SEI growth expected). After extensive evaluation electrochemical results (voltage curve analysis, capacity fade, energy Coulombic efficiency), tested by Post-Mortem analysis (CT, GD-OES,...

Due to their extreme volume expansion, Si/C-composites suffer from fracture or delamination and consequent capacity fading during the Li-ion cell operation. One approach reduce electrical contact loss improve performance is application of mechanical pressure on cell. Therefore, a comprehensive aging study Si/C|NMC811 pouch cells conducted with in different compression configurations as uncompressed under flexible fixed at levels range 0.08 MPa, 0.42 0.84 MPa. In-situ swelling measurements by...

Li metal deposition and internal short circuits (ISC) are directly observed in full cells using a cross-sectional situ optical microscopy set-up. The cell chemistries under investigation graphite/LFP graphite/NMC 622. Direct observations made on (i) lithiation gradients without deposition, (ii) ISC, (iii) with ISC by dendrite growing above the separator, (iv) induced mechanical closing of separator pores. speed fronts graphite/LPF was determined to be 2,736 ± 47 μm2 min−1 for LiC12 1,619 51...

Calendar aging of Li-ion batteries with Si/graphite electrodes was investigated within this study. A total 121 single-layer pouch full cells either graphite or (3.0 wt−%, 5.8 wt−% and 20.8 Si) anodes NMC622 cathodes the same N/P ratio were built on pilot-scale. studied at SoC 30%, 60%, 100%, as well temperature (25 °C, 45 60 °C) time dependence. The data analyzed in terms capacity fade a square-root behavior observed. Differential voltage analysis (DVA) has been performed function time....

Metallic lithium deposition is a typical aging mechanism observed in lithium-ion cells at low temperature and/or high charge rate. Lithium dendrite growth not only leads to strong capacity fading, it also causes safety concerns such as short-circuits the cell. In applications electric vehicles, use of batteries combines discharging, long rest time and charging phases. It foremost matter lifetime from perspective consumer or investor.

Durability and performance of Li-ion cells are impaired by undesirable side reactions, observed as capacity decreases resistance increases during their usage. This degradation is caused aging mechanisms on the material level including surface film formation, especially in case graphite-based anodes. The present study evaluates applicability glow discharge optical emission spectroscopy (GD-OES) a powerful tool to aging-induced formation graphite anodes cells, deposition metallic Li. technique...

Abstract Besides high energy density, fast‐charging capability, and costs, safety of Li‐ion batteries is fundamentally important – even after long‐term usage or abusive conditions. In this paper, a new combination accelerating rate calorimetry (ARC) coupled with mass spectrometer (MS), as well cell resistance audio recording was applied to study commercial 18650‐type cells. This novel ARC‐MS setup allows following the electrochemical thermal behavior simultaneously evolved gases during...

The safety of Li-ion batteries is the most critical many important characteristics and must be carefully considered. However, depending on aging conditions, can change drastically. We had recently introduced ARC-MS as a new tool for investigations, which an updated accelerating rate calorimeter (ARC) combined with mass spectrometer (MS). Additionally, our setup equipped by seven more low cost sensors (temperature, voltage, resistance, audio, strain, transmitted reflected ultrasound). In this...

Recently, the first sodium-ion cells have been commercialized and become available for consumers. Given, moreover, exciting announcements by several producers of such battery cells, it is great interest to analyze these commercial in order understand which materials are used how designed. Herein, two types commercially (cylindrical 1.5 Ah 18650 3.5 26700 cells) investigated regarding (i) their electrode chemistry, (ii) thermal properties upon discharge as a function applied C rate, (iii)...

Structure formation in an ionic liquid adlayer: First molecularly resolved scanning tunneling microscopy images of adlayer ([Py1,4]+ [FAP]− (see image)), evaporated on a Au(111) surface, resolve molecular pattern at 210 K with distinct short range order, indicating 2D solid, while room temperature, the mobility is too high to features, as expected for liquid.