Overview
The successful integration of electrically driven vehicles into Europe’s future transport system will depend on clear and transparent functional and safety requirements for the vehicles and their subsystems. These requirements play an important role in the transport system, in more the one way:
- The costumer needs to be confident regarding the safety of the vehicle.
- The road owner must know that vehicles conform to the infrastructure requirements.
- The automotive industry must have design standards to guarantee performance and reliability
The EVERSAFE project aims at evaluating every day safety for electric vehicles (EV). This motivates investigation over a broad scope of areas covering user attitudes and vehicle safety issues addressing active and passive safety. Uncertainty in the consumer’s perception of electric vehicles (e.g. safety of batteries in crash situations, risk of electric shock during charging, etc.) can lead to negative safety evaluations.
To address these concerns focus group sessions were conducted.
In total, 25 safety concerns distributed over 4 distinct categories were identified. It was concluded that safety-critical aspects vary both in terms of type of interaction and human involvement. These results allow to further adjust technical testing at the same time as the general public safety concerns are addressed.
Passive safety considerations for vehicles with traction batteries were studied since the layout of vehicle components is sensitive to the mechanical loading in collisions. A review of the distribution of crash types involving high acceleration or deformations was performed, where side and rear impacts were identified for further study. A model of an electric vehicle and critical sub components are under development.
The goal is to apply the load cases, identified from real world collisions, in simulations and establish critical conditions for the energy storage system (ESS) which are not fully addressed in current regulations and standards. In parallel to these investigations, the electro-chemical behaviour of ESSs is also being investigated.
Under the active safety scope, faults in the powertrain of a vehicle were studied since they can influence dynamic stability during driving. This can compromise safety for occupants and surrounding traffic. With this in mind, specific faults in an electric power train were identified and simulated. Three typical faults in an electric power train were selected, i.e. an inverter shut-down, a short circuit in the electric machine and a failure in the regenerative braking system. These were
taken for further analysis with real drivers at a test track experiment and in a driving simulator study.
Funding
Results
The work performed under EVERSAFE spans from the study of user expectations towards safety of EVs to the investigation of concrete passive and active safety issues. Safety concerns regarding the utilisation of EVs were collected from potential users. In order to use these findings to support the adoption of fully electric vehicles, it is important to consider that consumer’s worries are not exclusively dedicated to system faults but relate also with system
limitations and system features.
The research efforts undertaken under the active safety area have classified potential failures on an electric powertrain which are most likely to have a high impact on vehicle stability. Analysis has revealed that, for the given testing conditions, humans act as reasonable compensators for such failures contributing towards an improvement of vehicle dynamic stability.
Passive safety investigations have focused on the topics of crash compatibility and battery safety. The battery cells evaluated in the project have proven to be more resistant to abuse than expected indicating that current standards for electric vehicle components have already reached high safety levels. Furthermore, the studied vehicle structures have shown a good level of protection for high voltage batteries in crash situations. It was also concluded that the current guidelines for vehicle rescue after crash require updates in order to better fit EV. With these needs in mind the project has created a set of updated safe handling guidelines and recommended equipment for rescue services.