Prospects and limits for quantitative Energy dispersive X-ray spectroscopy (EDS) applied Li Ion batteries
Summary The most commonly used batteries at present and in the near future are Li-ion-based systems. The quantification of Li and limited spatial resolution of EDS analysis are bottlenecks to overcome. There the spectroscopy of low energy x-rays with the windowless Oxford extreme EDS detector open new prospects. We show spectra of Li metal directly […]
Positive Effects of Tab Design in Cylindrical Li-ion Cells – A Systematic Study on Pilot-Scale
Cylindrical cells (18650, 21700) are produced in the order of billions per year worldwide. In these cells, the electrodes are connected to the outer positive and negative connectors via tabs. However, not much is known about the effect of the tabs on cell performance and aging from experiments. The difficulty in such investigations is that […]
In-operando monitoring of internal pressure in lithium-ion batteries
In-operando monitoring of the internal pressure in lithium-ion cells allows to study the correlation of thermodynamic parameters with the commonly studied electric parameters in grahite/LFP lithium-ion battery cells. From the comparison of stored charge, incremental capacity peak intensity and position and state of health against pressure it was revealed that there is a strong connection […]
Investigation of impedance spectra of systems with distinctive resistive-inductive behavior using the generalized distribution of relaxation times analysis
The distribution of relaxation (DRT) times is a well-established method for the characterization and process identification of electrochemical systems in the frequency domain. In measured impedance spectra, it is in general a very challenging task to reliably extract system characteristics, to identify processes, and to evaluate the impact of operational variables. In many cases, changes […]
Towards direct recycling of lithium-ion batteries via sustainable and low-energy processes
The rapid growth of the electric vehicle (EV) market is a decisive step towards achieving the global greenhouse gas emissions reduction targets, but will be accompanied by a dramatic increase in the spent battery volume in the future.[1,2] In principle, spent batteries represent a valuable secondary material source that provides access to strategic and critical […]
Increasing the safety of lithium-ion cells through pressure-controlled gas removal
Lithium-ion cells can release significant amounts of energy in the case of mishandling or production defects. This leads to the development of high pressure and very high temperature inside the cell followed with release of toxic, explosive and flammable gases, usually known as Thermal Runaway (TR). The impact of a TR on the immediate environment, […]
Impurity particle contamination in lithium-ion batteries – a risk for safety-critical internal short circuits
A possible contamination with impurities in the cell production of lithium-ion batteries increases the risk of spontaneous internal short circuits (ISC), so that these faults are especially feared. Since detection of ISC in time for warning and effective countermeasures is difficult the safety risk is also increased. Various trigger methods are currently being discussed to […]
Generic Energy Flow Model for application in optimized combined operation of a Battery Energy Storage System and an Electrolyzer
The research project “ZET Reallabor Wunsiedel” collects data from different power plants at Wunsiedel energy park. The main goal of the project is to find a suitable strategy for the combined economical operation of an electrolyzer and a battery energy storage system (BESS). This optimization is achieved by a dynamic programming algorithm according to Bellman. […]
Direct Observations of Graphite Anode Lithiation and Internal Short Circuits by Li Metal Deposition using Cross-Sectional in situ Optical Microscopy in Li-Ion Full Cells
The anode is the rate-limiting compound during fast-charging of Li-ion batteries, due to the reduced mass transport through the electrode.1 Lithiation gradients within the anode build-up, leading to a higher state-of-charge at the surface of the anode, which favors Li metal deposition at these spots.2 Since graphite anodes undergo a characteristic color change from gray […]
Deciphering Li deposition and SEI with cryo-TEM & cryo-ET
Understanding in detail the behaviour of Li deposition and SEI formation is crucial for the rational design of stable Li metal anodes, but has remained tremendously challenging due to the extremely high sensitivity of metallic Li. [1] To address this issue, cryogenic electron microscopy (cryo-EM) has in recent years emerged as a powerful tool for […]