From electrode swelling to structural integration: a quantitative electro-chemo-mechanical framework for electric-vehicle batteries

Abstract

Electro-chemo-mechanical coupling is well established in electric-vehicle batteries, yet its translation from electrode behavior to pack- and vehicle-level performance remains difficult. This mini-review organizes the evidence around five transferable descriptors: electrode/cell swelling, contact or stack pressure, stiffness and strength, mechanical-abuse tolerance, and inactive structural mass or volume. Recent studies are examined to show how silicon-rich electrode deformation, pressure-dependent solid-state interfaces, and structural integration influence practical energy density and safety. Building on established mechanisms, we propose a mechanical penalty ledger that defines consistent accounting boundaries and connects cell-level specific energy with the mass and volume of constraint, protection, interconnection, and thermal-management components. An illustrative 60 kWh case study compares conventional, structurally optimized, and higher-specific-energy battery architectures. Under the stated hypothetical assumptions, a 12% improvement in cell-level specific energy yields only an approximately 3.3% improvement in pack-level specific energy when additional compression hardware is included. A break-even calculation identifies an illustrative maximum allowable compression-hardware mass of approximately 33.7 kg for the higher-energy configuration to outperform the conventional reference. The worked example is a sensitivity demonstration rather than experimental validation or a universal design threshold. This review therefore provides a transparent basis for evaluating when electrochemical improvements survive mechanical integration penalties, while emphasizing the need for experimentally validated load paths, ageing-conditioned safety limits, and complete component-level inventories.