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Electric vehicles (EVs) have garnered significant attention as a vital driver of economic growth and environmental sustainability. Nevertheless, ensuring the safety of high-energy batteries is now a top priority that cannot be overlooked during large-scale applications. This paper proposes an innovative active protection and cooling integrated battery module using smart materials, magneto-sensitive shear thickening fluid (MSTF), which is specifically designed to address safety threats posed by lithium-ion batteries (LIBs) exposed to harsh mechanical and environmental conditions. The theoretical framework introduces a novel approach for harnessing the smoothed-particle hydrodynamics (SPH) methodology that incorporates the intricate interplay of non-Newtonian fluid behavior, capturing the fluid-structure coupling inherent to the MSTF. This approach is further advanced by adopting an enhanced Herschel-Bulkley (H-B) model to encapsulate the intricate rheology of the MSTF under the influence of the magnetorheological effect (MRE) and shear thickening (ST) behavior. Numerical simulation results show that in the case of cooling, the MSTF is an effective cooling medium for rapidly reducing the temperature. In terms of mechanical abuse, the MSTF solidifies through actively applying the magnetic field during mechanical compression and impact within the battery module, resulting in 66% and 61.7% reductions in the maximum stress within the battery jellyroll, and 31.1% and 23% reductions in the reaction force, respectively. This mechanism effectively lowers the risk of short-circuit failure. The groundbreaking concepts unveiled in this paper for active protection battery modules are anticipated to be a valuable technological breakthrough in the areas of EV safety and lightweight/integrated design. [ABSTRACT FROM AUTHOR]

The interfacial debonding between the active layer and the current collector has been recognized as a critical mechanism for battery fading, and thus has attracted great efforts focused on the related analyses. However, much still remains to be studied regarding practical methods for suppressing electrode debonding, especially from the perspective of mechanics. In this paper, a pre-strain strategy of current collectors to alleviate electrode debonding is proposed. An analytical model for a symmetric electrode with a deformable and limited-thickness current collector is developed to analyze the debonding behavior involving both a pre-strain of the current collector and an eigen-strain of the active layers. The results reveal that the well-designed pre-strain can significantly delay the debonding onset (by up to 100%) and considerably reduce the debonding size. The critical values of the pre-strain are identified, and the pre-strain design principles are also provided. Based on these findings, this work sheds light on the mechanical design to suppress electrode degradation. [ABSTRACT FROM AUTHOR]

Due to the complex mesostructure and components of composite active layers in lithium-ion battery (LIB) electrodes, coupled with the concentration-dependent material properties and eigenstrains, efficiently estimating the effective modulus of the active layers remains a great challenge. In this work, the classic Mori–Tanaka method is found to be unable to estimate the modulus of the active layer. By realizing the importance of the mesostructure feature, a rod-rod model is proposed. The resulting modulus is expressed analytically. It is shown that the rod-rod model can accurately estimate the modulus evolution of the active layer if the material properties of the components and the evolution of volume fractions are known in advance. Moreover, a simplified rod-rod model is also developed to reduce the complexity of the proposed method. By knowing the volume fractions at two arbitrary states of charge and subsequently determining two constants, the simplified model can estimate the modulus efficiently. Considering both its accuracy and its simplicity, the simplified rod-rod model is the most suitable for the estimation. Thus, the methods developed in this work provide a new perspective for analyzing the material properties of composite active layers in LIB electrodes. [ABSTRACT FROM AUTHOR]

Prelithiation has been intensively investigated in high-capacity lithium-ion batteries (LIBs). However, the optimization of prelithiation degrees for long service life of LIBs still remains a challenge. The positive efffect of prelithiation on suppressing degradation of LIBs, besides directly pursuing the high first Coulomb efficiency which has been widely reported in the literature, is revealed and discussed based on an analytical model focusing on the interfacial delamination in electrodes. For full charge-discharge cycling, well-designed prelithiation can effectively suppress the delamination and reduce the debonding size by approximately 25%, compared with the case without prelithiation. For the strategy combining partial charge-discharge cycling and prelithiation, the largest reversible capacity without debonding can be significantly improved by approximately 100% with well-designed prelithiation. This work is expected to provide a prelithiation design principle and further improve the mechanical stability of LIB electrodes. [ABSTRACT FROM AUTHOR]