The Modern Age of Electric Cars

The modern age of electric vehicles started in 2011 ［www.ev-sales.blogspot.de］.As from 2009/2010，affordable electric vehicles entered the market，gradually replacing the previous leasing offers. Exemplary are Mitsubishi i-MiEV （2009），Chevrolet Volt （2010），Nissan Leaf （2010），Fisker Karma （2011） and Ford Fokus Electric （2011）. A breakthrough was the Tesla Roadster in 2008. As from 2011，nearly all markets registered a statistically significant number of electric vehicles，followed by double-digit or even three-figure annual growth rates as a result of the increasingly diversified offer.

Ultimately，the CO₂ fleet emission regulation was a key driver along with highly attractive incentives for electric vehicles in some regional markets，peaking i.e. in 17% market share in Norway in 2015. The average fleet consumption of 95 g CO₂/km targeted in Europe in 2020 is extremely ambitious and cannot be achieved with conventional technologies. As a result，all OEMs are forced more or less to electrify their vehicle fleets to avoid penalties of even market embargos. To make things worse，new competitors browbeat the established car makers by solely focusing on electric vehicles，Tesla in front.

In several markets，targets for the number of registered electric vehicles add to the political CO₂ emission regulations. As an example more than 5 Million registered electric vehicles were targeted in the US by 2015，compared to 1 Million in Germany in 2020 and even 6 Million in 2030，or 2 Million in France by 2020. The decisive factor to achieve these ambitious targets is the type and size of government-funded incentives and subventions. In Germany，end-consumers only profit from tax exemptions，along with R&D subventions to the industry，resulting in a market share of less than 0.5%. More successful are countries with direct purchase incentives. I.e. in the US，incentives up to MYM 7500 are granted resulting in 1% market share，topped by the Netherlands with 8000 and 4% market share，along with Norway with 50.000 and 17%. With approx. 430.000 electric vehicles sold in 2015 ［www.cleantechnica.com］，approx.1.13 Million electric vehicles are expected in the global market. Although these numbers widely fall short of the political targets，globally more than 6 Million electric cars appear to be realistic by 2020，resulting in 50% market share of vehicles with electrified power train world wide by 2025.

Periodically，this ambitious market run-up is accompanied by safety discussions of the new technologies. Key topics have been potential electric shocks due to high voltage on the car body after an accident，along with increased risks of vehicle fire，or even the explosion of Li-ion batteries. This paper will address the specific challenges of electric vehicles along with the adequate safety concepts. Ultimately，it will be shown how a similarly high level of safety as with conventional vehicles can be achieved with electric cars.

Specific Challenges to the Crash Safety of Electric Vehicles

Compared to conventional cars with a 12 V electrical system，vehicles with an electrified power train in addition have a high-voltage power supply （HV） providing voltages up to several hundreds of Volts Direct Current （DC），along with high voltage batteries with capacities up to 100 kWh. In addition to pure electric cars reloaded on battery-charging stations，fuel cell electric vehicles are offered，where the batteries are continuously charged during driving by the electric energy generated in the fuel cell. As a result，these vehicles need an additional tank to store hydrogen gas pressurized up to 700 bar. According to these characteristics，the following four new challenges must be addressed to the safety of electric vehicles：

1.Structural Safety：The integration of additional big aggregates such as the HV-battery or the electric motor could negatively impact the deformation characteristics of the car. Bloc formations of rigid components do not only reduce the vehicle crush zone，rather may they change the crash deceleration characteristics impairing the effectiveness of the occupant protection systems，their trigger times in particular. Other unfavorable consequence are the reduced compatibility in head-on collisions with other cars due to the higher stiffness of the vehicle front structure，the higher vehicle weight，or last but not least an increase of repair costs after a minor accident. This is particularly true for compact and subcompact cars where the share of the energy storages is approx.20% of the total vehicle mass. And just about all things，such smaller electric cars are a major market trend being very popular in cities and urban areas due to their still limited range.

2.High-Voltage-Safety：The electric drive train of electric and hybrid vehicles is powered by high voltage supplies up to several hundred volts. High voltage > 60