Intercalation-Induced Stress and Heat Generation within Single Lithium-Ion Battery Cathode Particles

Abstract

Intercalation-induced stress and heat generation inside Li-ion battery cathode ͑LiMn 2 O 4 ͒ particles under potentiodynamic control are simulated in this paper. We combined analyses of transport and kinetics in determining resulting stresses, which arise from concentration gradients in cathode particles, and heat generation. Two peaks in boundary reaction flux, and resulting stresses, were determined from the modeling of electrochemical kinetics and diffusion, using intrinsic material properties ͑resulting in two plateaus in the open-circuit potential͒ and the applied potential. Resistive heating was identified as the most important heat generation source. To probe the impact of the particle shape ͑equivalent radius and aspect ratio of an ellipsoidal particle͒ and the potential sweep rate on stress and heat generation, a surrogate-based analysis was also conducted. The systematic study showed that both intercalation-induced stress and time-averaged resistive heat generation rate increase with particle radius and potential sweep rate. Intercalation-induced stress increases first, then decreases as the aspect ratio of an ellipsoidal particle increases, whereas time-averaged resistive heat generation rate decreases as aspect ratio increases. This surrogate-based analysis suggests that ellipsoidal particles with larger aspect ratios are preferred over spherical particles, in improving battery performance when stress and heat generation are the only factors considered.

Chemomechanics of ionically conductive ceramics for electrical energy conversion and storage

“…Most continuum-level models of chemomechanical coupling have been developed to estimate diffusion-induced stresses-analogous to thermal stresses-which develop in the presence of a concentration gradient. A variety of single-particle models have been developed to estimate diffusion-induced stresses for battery electrode materials subjected to common electrochemical protocols [95][96][97] and incorporating a variety of effects including limited solid-solubility [98-100], particle shape [101,102], composition-dependent elastic modulus [103], and internal porosity [104]. Other particlelevel models have been developed which apply fracture mechanics failure criteria to study mechanical degradation of electrode materials, but these models considered static configurations-essentially the limit of zero rate-to identify critical length scales using fracture mechanics failure criteria.…”

Modeling Volume Change in Dual Insertion Electrodes

“…Recently, models have been developed that couple volume expansion of the active material and stresses during intercalation and deintercalation of a single porous electrode. 24,[28][29][30][31] They reveal the importance that a change in volume plays in the generation of stresses and strains, and how this may be linked to experimentally observed failure in the active material. …”

“…Recently, models have been developed that couple volume expansion of the active material and stresses during intercalation and deintercalation of a single porous electrode. 24,[28][29][30][31] They reveal the importance that a change in volume plays in the generation of stresses and strains, and how this may be linked to experimentally observed failure in the active material. [32][33][34][35] The model developed here accounts for the stresses that build up in porous electrodes due to volume change in the active material through the application of porous rock mechanics to porous electrode theory.…”

“…electrode thickness) conditions. 18,[21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] In many of these models, the dimensions of the porous electrode are often assumed constant and any volume changes in the active material result in only porosity changes. 21,22 Gomadam and Weidner 18 developed a model to allow both porosity and dimensional changes to occur.…”

Thermodynamics of electromechanically coupled mixed ionic-electronic conductors: Deformation potential, Vegard strains, and flexoelectric effect

“…Similarly, insertion and extraction of Li-ions in Li-battery electrodes produce large volume changes [26,27]. Most of the previous theoretical studies of strain effects in diffusional [28,29] and electrochemical systems consider this compositional lattice expansion as the only source of strain.…”