In practical applications, power cells face a mix of external influences such as
temperature variations and structural limits (rigid constraints) that trigger
intricate electrochemical and mechanical reactions. This study systematically
explores the temporal evolution of surface pressure in lithium-ion pouch cells
subjected to rigid mechanical constraints under varying thermal conditions, with
a specific focus on the interplay among mechanical stress, lithium
intercalation, and lithium plating. To investigate the battery’s electrochemical
and mechanical responses, this work integrates experimental measurements with an
electrochemical–mechanical coupling model. The analysis is performed under
initial loads of 0.3, 0.5, and 1.0 MPa at 25 °C (ambient temperature) and 0 °C
(representative low-temperature condition). At 25 °C, surface pressure followed
a two-stage pattern: first, stress relaxation occurred, followed by a shift into
quasi-steady cycling (cycle-to-cycle variations are minimal). This pattern is
largely driven by the reversible volume changes in the electrodes as lithium
ions are alternately inserted (intercalation) and removed (deintercalation)
during electrochemical cycling of the cells. At 0 °C, slower ion transport and
reaction kinetics promoted lithium plating, causing irreversible anode expansion
and a continuous rise in surface pressure. Concurrently, the depletion of active
lithium diminished the electrode’s maximum achievable state of charge (SOC).
This limitation curtailed the degree of electrode expansion and contraction
throughout charge–discharge cycles, resulting in a decrease in the amplitude of
pressure fluctuations on the battery surface during cycling. Numerical
simulations confirmed that lithium plating and SOC degradation collectively
shaped the mechanical response at low temperatures. The proposed model
accurately replicates experimental pressure evolution and distinguishes between
reversible and irreversible contributions to volume changes. This work reveals
how temperature and mechanical loading jointly regulate surface pressure and
capacity retention, offering insights relevant to battery pack design and the
optimization of low-temperature performance.