Electric mobility has been a ubiquitous topic – not only since the Federal Republic of Germany launched the National Electric Mobility Development Plan which, among other things, pursues the aim of one million electric vehicles being operated on German roads by 2020. One task towards that aim is to consider the interdependency of the systems including electric vehicle, charging connection and charging system, which were mostly standardised autonomously. In order to avoid personal injury and property damage during the charging process of vehicles it may be necessary to define requirements for the safety of this total system. For this purpose, the German Federal Highway Research Institute (BASt) commissioned SGS-TUEV Saar GmbH, Competence Center Functional Safety, to perform a risk analysis aimed at studying the safety aspects when charging an electric vehicle to indicate hazards during a charging process which may not have – or only insufficiently – been examined so far. Necessary measures should be defined and selectively validated by means of tests in order to reduce identified risks to a sufficiently low level. In essence, the project analysed what potential risks (Risk is defined as the description of an event with the potential of having negative effects. Risk is generally viewed as the product of the occurrence probability of an event and ist consequence. (Source: Wikipedia)) occur when charging an electric vehicle. Based on a research of standards the question of where a need for normative and legislative action exists was answered. For this purpose the following focal areas were elaborated: - Illustration of possible safety-critical conditions during charging; - Allocation of the safety-critical conditions to the subsystems infrastructure, cable and vehicle; - Definition measures to increase safety during charging; - Identification of the responsibility for assurance of safety; - Disclosure of required regulatory measures. In the first step a risk analysis was performed in order to indicate the potential risks incurred when charging an electric vehicle. The risk analysis was initially performed without consideration of protective measures which have already been established by standards or laws. Subsequently, the examination of the risks iteratively continued in two respects: a) Consideration of existing normative and/or legal requirements that were researched in parallel to the risk analysis; b) Description of complementary technical and/or organisational measures to further reduce risks which have not been covered. Subsequently, the risks were re-evaluated in order to indicate whether or not the existing and/or newly defined measures are able to sufficiently reduce the identified risk. Generally, the risk analysis revealed a broad existing coverage of possible risks by standards and regulations and/or legal requirements. Risks not currently covered could be addressed and effective possible solutions proposed. Consequently, no relevant risks remain unaddressed if all the proposed problem-solving approaches are implemented. However, it is also obvious that an urgent need for action exists with respect to certain issues. As a result, a concrete need for action could be derived with respect to the following issues: - One of the major risks identified was charging at a typical household power socket without the use of an additional protection device integrated in the charging cable. When charging cables with protection devices are used their protective effect not least depends on the performance of regular technical inspections; - Furthermore, the electromagnetic fields emanating from a charging cable at high currents (future quick-charging systems) were identified as relevant; more in-depth studies are required here; - In the interest of risk minimisation the maximum permissible weight of the charging equipment should be limited as well; - In addition to the technical hazards, the risks resulting from the operation of the equipment were examined. Some of these potential hazards can be counteracted by appropriate instructions in the operator manual of the electric vehicle. Among others, this concerns the handling of the charging equipment in public spaces. The measures identified and still to be implemented reveal that the current state of standardisation and legal requirements is not fully sufficient yet in order to reduce all the risks which have been identified and indicated. However, the results of the study also show that safety is not only assured by a single subsystem but by the safe interaction of all the components, also in combination with the behaviour of the users and participating persons. (Author/publisher)
Samenvatting