55kWh급 전기차용 리튬이온전지의 양극활물질에 따른 전지 성능 비교 분석

Abstract

As the demand for EVs has recently increased, the importance of LIB used as a power source for EVs has also increased. The positive electrode material, which is one of the four elements constituting the LIB, is an important factor influencing the performance of the battery by determining the capacity and power of the battery according to the applied material. Therefore, in this study, NCM, LFP, and LMO, which are used as representative positive electrode materials, are applied to the battery cells, and further, the battery characteristics at the system level according to the application of different positive electrode materials are compared and analyzed. To this end, Each of the 18650 cylindrical battery cells was modeled by applying different positive electrode active materials. Battery modeling was based on a database provided by Gamma Technologies' LIB simulation, GT-AutoLion. In order to analyze thermal stability and capacity loss according to the temperature of the battery cell by applying different C-rate discharge and temperature conditions by for each positive electrode active material, an electrochemical-based 0D analysis was performed. In the simulation, the analytical temperature was set at room temperature so that the battery could perform optimally. Lumped battery pack modeling was performed to extend the modeled battery cell to an EV battery pack. At this time, the battery pack was modeled by individual applying NCM622, NCM811, LFP, and LMO positive electrode active materials in accordance with the capacity standards required by the target EV. The modeled battery pack was combined with GT-Suite, a 1D-based automotive comprehensive simulation software, to build an EV model. The constructed EV model applies the drive cycle measurement method such as FTP-75, US06, and WLTC, etc. to measure fuel efficiency by assuming an environment similar to the actual operating conditions. after that time, EV models equipped with battery packs to which different positive electrode active materials were applied were comparative analysis and verified for reliability. In addition, using the MACCOR 4300 battery charger/discharger, Different C-rate discharge tests of the battery cells were performed under the same temperature conditions as the simulation. the validity of the simulation was verified through this battery cell experiments.