Impact of different aging mechanisms on thickness change and quick-charge capability of lithium-ion cells

Significance 

Everyone is exposed to lithium-ion batteries in our daily lives in one way or another. Most of the electrical devices use lithium-ion batteries. Being rechargeable ensure that the users get access to power even when they are not near the power sockets and other outlets. Recently, its used to have encroached into the automobile industries for the manufacture of electric and hybrid cars due to its high-power energy density. However, their functions and efficiency over time are always affected by various aging mechanisms that the cells undergo when in use. This has triggered various researchers on the impacts of such aging mechanisms on the lifetime, efficiency and normal operations of lithium batteries.

Florian Grimsmann and colleagues at Daimler AG research, and Development in Germany conducted research aimed at investigating the effect on the lithium-ion batteries as a result of various aging mechanisms that degrade the batteries in their lifetime. They went ahead and applied different methods in order to achieve and separate the various aging mechanisms and found out how each one of them affects the thickness, life, and fast chargeability of the batteries. Their excellent research work has been published in Journal of Energy Storage.

The authors analyzed the three primary aging mechanisms in lithium-ion batteries: calendar aging, cycle aging and aging due to plating. The three are caused by various phenomena, for example, charging and discharging of the batteries leads to cycle aging. From the conducted experiments, the researchers further realized that aging due to plating and calendar aging leads to a massive decrease in the fast chargeability.

As a significant contribution to the study, the authors observed that each of the three aging mechanisms showed very distinct features and characteristics from each other. This means that they also have different effects on the thickness, current, and rechargeability of the lithium-ion cells. For instance, it was observed from the experiments that calendar aging leads to an increase in the thickness change while charging and discharging of the lithium cells the converse is true for cycle aging. On the other hand, the change in the thickness was almost negligible for aging mechanism caused by lithium plating. Other factors such as the degradation of the anode material and formation of gases within the cells also lead to aging and hence contributing to the effects.

According to research team, the three aging mechanisms also have different maximum allowable charging current. It is undoubtedly that lithium-ion cells undergo majorly cycle and calendar aging on a daily basis as compared to lithium plating. Hence cycled aged cells can cope with comparative high charging current than fresh cells. Lithium plating aging and calendar aging, however, have not many differences regarding the decrease in fast chargeability with advanced aging. It is therefore essential to determine the aging mechanisms in the lithium batteries we use, the impact and how they can be handled to maintain the functionality and efficiency of the lithium-ion cells.

Reference

Grimsmann, F., Brauchle, F., Gerbert, T., Gruhle, A., Parisi, J., & Knipper, M. (2017). Impact of different aging mechanisms on the thickness change and the quick-charge capability of lithium-ion cellsJournal of Energy Storage14, 158-162.

 

Go To Journal of Energy Storage

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