3D-Printed Testing Plate for the Optimization of High C-Rates Cycling Performance of Lithium-Ion Cells

Abstract

Nowadays, long charging times have become one of the main limitations to a greater worldwide spread of electric vehicles (EV). Enabling high C-rates charging is a promising approach to eliminate this problem and alleviate range anxiety. When a battery is charged at high currents, several factors have to be taken into account. Temperature is certainly a key parameter because when it is too high this can lead to degradation of components (binder, electrolyte, active material, etc), however, when it is too low intercalation kinetics becomes sluggish. Using 3D-printed testing plates (PP3D plates) with Li-reference electrode, we developed a tool for electrochemical investigations of pouch cells. These plates enabled to build a new well-designed 3-electrode pouch cell. This setup allows the identification of the best high C-rate cycling procedure to improve the performance and cycling life of the lithium ion cells. We explored the electrochemical behavior of NMC811 cathodes and graphite anodes, during high discharge C-rates test up to 7 C and charge C-rates up to 2 C. Moreover, the temperature influence on charging performance and longtime cycling stability is investigated. The cells cycled at 25 °C using optimized procedures reached an 80% state of health after more than 1000 cycles.

A Direct Comparison of Pilot-Scale Li-Ion Cells in the Formats PHEV1, Pouch, and 21700

“…Reproduced cells of the respective formats show very similar behaviour. As expected, 30,48 increasing C-rates lead to decreased capacity at the end of the discharge as well as lower levels of the voltage curves. At increased C-rates, differences in the voltage curves between the three formats emerge.…”

Applying Established Water-Based Binders to Aqueous Processing of LiNi0.83Co0.12Mn0.05O2 Positive Electrodes

“…We already showed in our previous work that with 93% CAM, 4% conductive additives and 3% binder we were able to produce a well performing, NMP-based positive electrode. 66 Therefore, this formulation was used for the NMP-based reference electrode and most of the water-based electrodes. All electrodes were coated to an industry relevant areal capacity of 2.6 mA h g −1 and were calandered to a high density of up to 3.5 g cm −3 .…”

Efficient Workflows for Detecting Li Depositions in Lithium-Ion Batteries

“…GD-OES is a spectroscopic method that provides depth-resolved information about the elemental distribution and in a sample from the anode surface to the current collector. 12,[16][17][18]35,36,47,76,78,131,[160][161][162][163][164][165][166] An Ar plasma is used to remove sample atoms layer by layer in a sputtering process. The ejected atoms undergo further collisions with the plasma components, getting excited and emitting photons of characteristic wavelengths upon energy release.…”

“…8,10,11,34,35,37,38,40,223,224 Li depositions can be avoided by keeping the anode potential positive vs Li/Li + . 8,10,34,40,45,57,86,162,181,[225][226][227] One difficulty is that many cell types (e.g. all commercial cells) do not contain a reference electrode, so that the anode potential cannot be measured.…”