Lithium-ion batteries cell thickness changes as they degrade. These changes in thickness consist of a reversible intercalation-induced expansion and an irreversible expansion.
Lithium-ion batteries cell thickness changes as they degrade. These changes in thickness consist of a reversible intercalation-induced expansion and an irreversible expansion. In this work, we study the cell expansion evolution under variety of conditions such as temperature, charging rate, depth of discharge, and pressure.
How does thermal expansion affect lithium ion batteries?
Thermal expansion depends on the current, DOD and the location on cell. Larger thermal stress can lead to capacity fade and safety issue of lithium-ion batteries. Thermal expansion is induced by thermal stress due to the temperature deviation during charge-discharge cycles.
During charging process, lithium-ion batteries undergo significant lithiation-induced volume expansion, which leads to large stress in battery modules or packs and in turn affects the battery's cycle life and even safety performance [, , , ].
Why do lithium ion batteries undergo lithiation expansion during charging?
Lithium-ion batteries usually undergo obvious lithiation expansion during charging, because the lithiation-induced volume expansion of the anode materials (graphite and Si/C) is usually larger than the delithiation-induced volume contraction of the cathode materials (LiFePO 4 and LiNi x Co y Mn 1-x-y O 2) .
Why do lithium-ion batteries have abnormal volume expansion?
However, lithium-ion batteries suffer from abnormal volume expansions under extreme operation conditions, such as volume expansion overshoot during high-rate charging and irreversible volume increase during long-term cycling, mainly induced by side reactions inside the batteries.
What is the volume expansion behavior of pouch lithium-ion batteries?
Firstly, the volume expansion behaviors of the pouch lithium-ion batteries are measured at different temperatures and charging current rates. Battery volume expansion overshoot appears during charging at high C-rates and low temperature (≥3/2 C at 25 °C, ≥1/2 C at 10 °C and ≥1/5 C at 0 °C).