Increasing the Discharge Rate Capability of Lithium-Ion Cells with Laser-Structured Graphite Anodes: Modeling and Simulation

Abstract

A physical-chemical model is suggested, which is able to describe the enhanced discharge rate capability of lithium-ion cells by using laser-structured graphite anodes. Recently published test data of coin cells comprising unstructured and structured graphite anodes with LiNi 1/3 Co 1/3 Mn 1/3 O 2 cathodes is used for the presented purpose of modeling, simulation and validation. To minimize computational demand, a homogenized three-dimensional model of a representative hole structure is developed, accounting for charge and mass transport throughout the cell layers and one-dimensional diffusion within radial-symmetric particles. First, a standard pseudo-two-dimensional model is calibrated against rate capability test data of coin cells with unstructured anodes. The calibrated parameter set is transferred to the three-dimensional model in order to simulate the transient voltage response and the discharged capacity depending on the applied Crate. The simulation data shows excellent agreement with experimental data for both cell types. Three stages of rate capability enhancement are identified showing an improved relative capacity retention of 11−24% at 3C. Experimental and simulation data reveal a restricted Crate window, which can be positively affected by the structuring process, whereas both shape and pattern of the structuring process can be further optimized with the model.

Classification of Calendering‐Induced Electrode Defects and Their Influence on Subsequent Processes of Lithium‐Ion Battery Production

“…To a lesser extent, the defect should have no influence. This is shown by investigations into the long‐term behavior of laser‐structured electrodes, which are, in principle, also perforated . Foil tear has a major influence on almost all subsequent processes.…”

Low-tortuosity and graded lithium ion battery cathodes by ice templating

“…† The DIT (LP-S) electrode maintained the highest capacities, realising 7.9 mA h cm À2 (94 mA h g À1 ) at an ultra-high current density of 15 mA cm À2 . Above 15 mA cm À2 ($10 times the current applied to the SC electrodes conventionally 45,57 ), the difference between electrodes decreased markedly due to Li metal anode deterioration and the consequent very large polarizations. 31 To match the performance of the ultra-thick DIT electrodes at the highest rates, new Li metal anode technology may be required.…”

EIS Study on the Electrode-Separator Interface Lamination

“…To improve the fast-charging capability as well as the travelling distance of the EVs, ongoing research mainly addresses the basic cell components like active materials [1,2], electrolyte [3], separator [4][5][6][7], and manufacturing steps. Different manufacturing techniques, such as ultra-thick electrodes [8][9][10][11], calendering process [12], controlled stack pressure [13,14], laser structuring [15][16][17][18][19][20] and lamination [21], have been applied to increase the power density, energy density, lifetime and for cost reduction of LIBs. Typically, the calendering process improves the contact situation between the active material particles [14], which leads to an increase of the rate capability as well.…”