To ensure future worldwide mobility, hydrogen storage in combination with fuel cells for on-board automotive applications is one of the most challenging issues. Potential solid-state solutions have to fulfil operating requirements defined by the fuel cell propulsion system. Important requirements are also defined by customer demands such as cost, overall fuel capacity, refuelling time and efficiency. It seems that currently none of the different storage solid state materials can reach the required storage densities for a hydrogen-powered vehicle. New strategies for storage systems are necessary to fulfil the requirements for a broad introduction of automotive fuel cell powertrains to the market. The combination of different storage systems may provide a possible solution to store sufficiently high amounts of hydrogen.

The energy storage system is of decisive importance for all types of electric vehicles, in contrast to the case of vehicles powered by a conventional fossil fuel or bio-fuel based internal combustion engine. Two major alternatives exist and need to be discussed: on the one hand, there is the possibility of electrical energy storage using batteries, whilst on the other hand there is the storage of energy in chemical form as hydrogen and the application of a fuel cell as energy converter. The advantages and limitations, and also the impact of both options are described. To do so, existing GM concept vehicles and mass production vehicles are presented. Eventually, an outlook is given that addresses cost targets and infrastructure opportunities as well as requirements.

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One of the major challenges for the automotive industry will be the release and validation of cooperative and automated vehicles. The immense driving distance that needs to be covered for a conventional validation process requires the development of new testing procedures. Further, due to limited market penetration in the beginning, the driving behavior of other human traffic participants, regarding a mixed traffic environment, will have a significant impact on the functionality of these vehicles.In this article, a generic simulation-based toolchain for the model-in-the-loop identification of critical scenarios will be introduced. The proposed methodology allows the identification of critical scenarios with respect to the vehicle development process. The current development status of the cooperative and automated vehicle determines the availability of testable simulation models, software, and components.The identification process is realized by a coupled simulation framework. A combination of a vehicle dynamics simulation that includes a digital prototype of the cooperative and automated vehicle, a traffic simulation that provides the surrounding environment, and a cooperation simulation including cooperative features is used to establish a suitable comprehensive simulation environment. The behavior of other traffic participants is considered in the traffic simulation environment.The criticality of the scenarios is determined by appropriate metrics. Within the context of this article, both standard safety metrics and newly developed traffic quality metrics are used for evaluation. Furthermore, we will show how the use of these new metrics allows for investigating the impact of cooperative and automated vehicles on traffic. The identified critical scenarios are used as an input for X-in-the-Loop methods, test benches, and proving ground tests to achieve an even more precise comparison to real-world situations. As soon as the vehicle development process is in a mature state, the digital prototype becomes a “digital twin” of the cooperative and automated vehicle.