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2021
Poster
Titel
Simulation based Energy Performance Analysis and Economic Assessment Na/NiCl2 Batteries compared to Li-Ion Batteries Operating in a PV Home Storage System
Titel Supplements
Poster presented at 2nd International Sodium Battery Symposium - SBS2, online (13.-14.1.2021)
Abstract
In this work, a simplified thermo-electric model of a Na/NiCl2 battery was developed in Modelica/Dymola. The phenomenological approach uses experimental data to set the main battery module parameters and process characteristics such as heat capacity, heat loss as a function of temperature, self-warming as a function of discharge power and the maximum charging rate depending on the state of charge. The functionality of the battery model was validated based on battery module test data. The battery model was included into a power-flow model of the entire PV home storage system. Therefore standardized, synthetic user load profiles and PV production profiles were generated based on the VDI 4655 standard. By means of annual simulations, a parameter study was carried out in order to identify the most suitable dimensioning of the battery and the installed PV area in respect to energetic evaluation parameters of the battery, such as battery efficiency, battery heating requirements, equivalent charge/discharge cycles and idle times. Furthermore, the system's overall performance was rated, e.g. by the own domestic consumption rate and system efficiencies. Furthermore, a simple ready-made model of a Li-Ion battery was integrated into the power-flow model for the same PV home storage dimensioning in order to compare the performance of both battery types. Based on the yearly data, the economic parameters of the entire PV home storage system with a Na/NiCl2 battery and a Li-ion battery were evaluated. The analysis shows that the application of Na/NiCl2 batteries as a home storage is economically viable, even though energy efforts for heating the module (resp. the heat loss of the module) is the crucial parameter. Li-Ion batteries are very competitive due to the low investment costs, but higher degradation rates, lower overall operation times and security issues must also be considered in the comparison. However, economy of scale will lead to lower investment costs for Na/NiCl2 batteries in the future, enabling even better economic parameters.