CHARACTERIZATION OF RESERVED ENERGY STORAGE SYSTEM (RESS) BASED ON LI-ION NCA BATTERY SUBJECTED TO DYNAMIC IMPACT LOADING

• Main Author: Fadillah, Hafiz
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/54297
• Institution: Institut Teknologi Bandung

The Li-ion NCA is commonly used as the power storage for many devices, including electric vehicles. Damage due to the external dynamic loading, such as impact loading, may deform the battery and cause catastrophic failures such as thermal runaway, fire, or an explosion. In this research, the cylindrical Li-ion NCA battery with 18650 configuration was evaluated using numerical and experimental methods to characterize its dynamic impact properties. The Li-ion components were tested in static mode for the casing, separator, aluminum foil, copper foil, anode, cathode. The jellyroll component was tested on static and dynamic loading configuration using Split Hopkinson Pressure Bar (SHPB). The full system battery was also evaluated in static and dynamic compression loading conditions. The static tensile test of the battery components shows that most of the materials have a certain anisotropy resulted from the manufacturing process in which the longitudinal (machining direction) property has a higher value than that of the transverse direction. The static compression of the jellyroll results show that addition electrolyte could increase the stress response, which is also found on the dynamic compression test that exhibits strain-rate dependency. The compression test on the Li-ion NCA battery shows that variation of state-of-charge (SOC) does not affect the load response of the battery when loaded axially. However, reduction of the failure strain has been determined from 5.8mm at SOC 0% to 4.3 mm at SOC 50%. Numerical simulations of several tests have been conducted by using the data obtained from the experiments. Static compression of the jellyroll was built using the Deshpande-Fleck foam model, and the SHPB model was built using the Fu-Chang foam model. Both models have produced a good correlation with the experimental result, both in dry and wet specimen conditions. Simulation of the compression test on the Li-ion NCA battery has also been performed. The current model has a good correlation on the initial load-displacement result but still unable to correlate well with the experiment on the jellyroll-dominated region. Design of Split Hopkinson Tensile Bar (SHTB) is also performed and checked numerically with two signal strengthening strategies. The results show that the signal strengthening strategies are working, and the material tested shows a strain-rate-dependent behaviour. The result obtained in this study could further improve the understanding of the mechanical response of the battery, and the material data gathered can be used for a simulation involving a battery or the development of a testing standard for a battery.