It might be hard to believe, but innovators have
been working on electrical vehicles for almost two
centuries. The first 'experimental' electrical vehicles
were ready as early as 1830s in the Netherlands and
the USA. Fast Forward to 2020 and now we are
preparing for a wide-scale penetration of EVs. Many
players already have launched electric versions and
many are looking forward to entering the EV space.
Safety of EVs remains a topic of attention and along
with a few other factors, will decide the pace at
which users embrace EVs. Many of the issues
pertaining to the safety of Electric Vehicles call for
technical breakthroughs. While many safety issues
are surfacing up, as the number of EV users is
becoming considerable and 'test worthy'. In this
article, we are taking a close look at Electrical
Vehicle Safety and will be going through the present
safety concerns, standards and regulations and
possible technologies which can accelerate bypassing
these safety concerns.
For ease of presentation, we have divided safety concerns and challenges in three main categories as below. Under each category, we will take a close look at present safety regulations, safety challenges and possible technologies.
Electrical vehicles are different from conventional IC engine powered vehicles due to multiple factors; most important being the lack of IC engine and presence of a battery pack. Structurally also, EVs are different than the conventional vehicles which changes their behaviour in the crash conditions.
Presence of battery pack drastically changes the post-crash behaviour of the EVs. Here are some prime considerations about crashworthiness of EVs :
1. During and after crash, how sturdy the EV structure is to ensure safety of the passengers within. Factors like mass distribution and layout also play a crucial role in the crashworthiness of EVs. EV’s response to front and side impacts is also crucial in determining its crashworthiness.
2. Maintaining integrity of battery and the electrical parts post a collision, preventing electrolytic material and fumes to enter in the passenger compartment, preventing EV components from getting damages due to the chemicals are unique safety issues relating to EVs during a crash.
3. Quite a few factors might lead to fire in Electric Vehicles during a crash. These factors include high temperature, short circuits, high voltage cables, chemical reactions etc. Lithium, which is one of the important components of Li Ion batteries is highly reactive and electrolytes are highly flammable in nature.
4. In the future, Electric Vehicles run-in on Hydrogen Fuel Cells might become a normal. Hydrogen, being the smallest molecule, is very difficult to contain in crash situation. Hydrogen is extremely explosive with right oxygen mix. What makes use of Hydrogen even more challenging is the fact that Hydrogen cannot be used with Odourants as CNG or LPG as they contaminate the fuel cells.
It is definitely worth noting that the presently available stats about EV accidents and casualties are expected to change steeply because the number of Electric vehicles on road is very less as of now and will increase exponentially over the period.
Pedestrian Safety :
From the pedestrian safety point of view, major shortcoming of electric vehicles is their silence; i.e. the lack of engine sound. Numerous studies conducted by organisations world wide highlight that pedestrians are unable to know of an Electric Vehicle coming from behind because of their silent operation. Studies further show that pedestrians get multiple clues from the sound of conventional vehicles – speed of the vehicle, size of the vehicles, possible trajectory of the vehicle, driving style of the driver etc. In case of an electric vehicle, all these clues are absent. The tyre sound or sound of air cut by the vehicle is not significant enough to create any auditory clues. The urban areas have stringent speed limits and at lower speeds, tyre noise is even lower increasing the risk to pedestrians.
In order to solve this problem, various solutions are being tried out. As a case in consideration, Nissan’s technology of adding approaching Vehicle Sound for Pedestrians (VSP) has shown to be successful. As per the regulation, The device will automatically generate a sound from the start of the car up to the speed of approximately 20 km/h, and during reversing. The sound-emitting device will be obligatory in all new e-cars as of 1 July 2021.Here is a webpage which talks in detail about the regulatory requirements for the noise generator.
Safety of First Respondents
First respondents are the individuals who are the firsts to approach an EV after a crash or an accident. A first respondent could be a civilian near the crash site or a cop at the sight of incident.
In case of conventional IC engine vehicles, possibility of explosion due to gasoline catching fire poses the risk to the first respondents. In case of Electric Vehicles, there are multiple unique safety issues from first responder point of view.
Here are some of the most important issues :
- There are high chances that post collision, the vehicle body has been connected to the battery and thus carries a high voltage. A first respondent is at risk of an electric shock is this high voltage is not released from the vehicle body.
- Due to leakage of electrolytes or due to high temperatures resulting out of chemical reaction between battery fluids, EV can be vulnerable to fires.