How do lithium ion batteries expand?

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.

What causes volume expansion of lithium ion batteries?

Volume expansion of lithium-ion batteries is caused by lithium (de-)intercalation, thermal expansion, and side reactions (such as lithium plating and gas generation) inside the battery. In this work, the battery is kept in a constant ambient temperature.

Does lithium-ion battery thickness change during cycling?

The expansion mechanism of LIB with different SOCs is revealed. A SOC estimator utilizing the expansion feature is presented and verified. Lithium-ion battery (LIB) thickness variation due to its expansion behaviors during cycling significantly affects battery performance, lifespan, and safety.

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.

How does lithiation affect lithium ion batteries?

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 [ , , , ].

What is expansion overshoot in lithium ion batteries?

The expansion overshoot phenomenon, where the battery volume increases beyond the nominal maximum during the constant current charging stage and then decreases during the constant voltage charging or rest stage, can be observed in the lithium-ion batteries charged at high rates or low temperatures [ , , , ].