Vehicle power system requirements are increasing rapidly. Apart from modifications and optimizations of the existing systems, the introduction of a higher DC voltage level and new supply architectures is discussed. Especially the demands on the energy storage devices have to be fully included into the computer-based development process of the vehicle electric systems. Hence, powerful simulation models are required, representing a good compromise between simulation precision and computation time. The thesis reveals that non-linear lumped-element equivalent-circuit models meet the above described demands in the most promising manner. The power of this modeling concept is the most demonstrated for supercapacitors, lithium-ion and VRLA batteries. To determine suitable equivalent-circuit topologies as well as to parameterize the models, the method of electrochemical impedance spectroscopy is employed. Sets of impedance spectra are systematically measured. In aditional, for a meaningful interpretation of the aquired impedance data, the most important aspects of the theory of the modeled energy storage devices are briefly reviewed. After this, the proposed simulation models are fully parameterized, implemented into a time domain simulation tool and finally thoroughly verified .Due to its unique versatility, the impedancebased modeling approach can easily be adapted to other storage technologies in the future.