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Term:OSL5b213dbe439441cbbf0b99baf6a3fe0d: Difference between revisions
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Revision as of 16:36, 8 February 2023
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=== Battery cell types === | === Battery cell types === | ||
* Commercially available pouch cell batteries | |||
** Bought in publicly funded projects | |||
** Various manufacturers | |||
*** Kokam (Graphite || Nickel rich LithiumNickelCobaldOxide) | |||
*** ConradEnergy (Graphite || LithiumCobaltOxide) | |||
** Various chemistries | |||
*** Cells from publibly funded projects --> data available for | |||
*** from typical battery cells | |||
**** Typical anode (negative electrode) materials: Graphite, LTO | |||
**** Typical cathode (positive electrode) materials: LCO, NMC(111, 532, 622, 811), NCA, LNCO, LFP | |||
**** Where available: link to terms defined in BattINFO | |||
* Post Mortem procedur: Post-Mortem experiments, involving cell opening and lab cell construction were carried out under argon atmosphere. A glove box (MB200MOD, M. Braun Inertgas-Systeme GmbH) ensured a low content of water and oxygen below 1 ppm. | |||
** Discharge of battery cell to lower operational voltage limit | |||
** Opening of pouch cells in inert gas atmosphere | |||
** Harvesting electrodes from pouch cells | |||
*** Washing of electrodes with DMC (or other solvent that is part of the reference electrolyte mixture to be used in later step) to remove residual lithium salts from the original electrolyte | |||
*** Removing back side coating for electrical contact in laboratory cell | |||
** Building three electrode laboratory cells with metallic lithium reference electrode: Three-electrode electrochemical tests were carried out in ECC-PAT-Core test cells, supplied by EL-CELL GmbH. From a battery cell opened at discharged state, the electrodes were harvested. To achieve electrical contact from the backside, the coating was removed from one of the sides of the electrode sheets, and discs were punched out. Besides the electrodes, a lithium reference electrode, integrated into a glass fiber 260 µm separator, a 200 µm plunger, and 150 µl of the electrolyte LP57 (1M LiPF<sub>6</sub> in EMC/EC solution, with a weight ratio of 7:3, supplied by BASF) was used to build a test cell. Thereby, the individual electrodes’ potentials became accessible for investigation. | |||
*** EL-CELL Cell Casing (https://el-cell.com/<nowiki/>),Type: ECC-Pat (ring reference electrode) or ECC-Ref (dot shaped reference electrode) | |||
*** Reference separator Cellgard (ECC-Pat) / EL-CELL glas fiber | |||
*** Reference electrolyte LP57 | |||
** (Re)creating a uniform SEI (solid electrolyte interphase) with 3 to 5 C/20 constant-current cycles including constant-voltage at 4.2 V cell voltage until (cut-off) current of C/100 was reache | |||
** Analysis of the chemical composition of the electrodes havested from the pouch cells: From the negative and positive electrodes, two samples at each SoC with a weight of about 1 g were cut and individually dissolved in 30 ml of ''aqua regia'' - a mixture of nitric acid and hydrochloric acid. The resulting solutions were analyzed by inductively coupled plasma-optical emission spectrometry (ICP-OES). The measurements were carried out using a Vista-PRO radial, supplied by Varian Inc. | |||
* All electrochemical tests were conducted within a controlled environment at a constant temperature of 25 °C. Depending on space requirements and duration of the experiment, a Vötsch VT<sup>3</sup> 4018-S, a Vötsch VT 4021-S, a Weiss WKL 34/70, or a Memmert IPP 260<sup>PLUS</sup> were used to control ambient conditions. A Maccor Series 4000 galvanostat was used to perform cycling tests. | |||
=== Data source / Measurements === | === Data source / Measurements === | ||
* Cell tests from our lab | |||
** Maccor Series 4000 galvanostat | |||
** Electrochemical tests at 25 °C constant temperature in temperature chamber | |||
* Slow (small C-Rate <= 0.1 C) cycling tests | |||
** High accuracy data recordings with dV <= 5 mV and at least 100 data points per half cycle | |||
* Incremental capacity analysis to identify stages and phases utilized within the voltage range, specified in the data sheets of respective parent pouch cells, which the electrodes for the laboratory cells where harvested from | |||
=== Result === | === Result === | ||