Electric vehicles and hybrid electric vehicles safety considerations

Background

There are three types of electric vehicles and hybrid electric vehicles:

• Battery electric vehicles use a large capacity battery and one or more electric motors to drive the vehicle. The battery is charged from the electricity supply network when the vehicle is not in use. Some energy may be recovered during braking.
• Hybrid electric vehicles typically have two sources of energy: an internal combustion engine, diesel or petrol, and a battery. The vehicle automatically selects the most fuel efficient source of power to meet the driver’s commands and may use both simultaneously. Both the internal combustion engine and vehicle braking and recovery systems are used to charge the battery.
• Plug-in hybrid electric vehicles are similar to hybrid electric vehicles but with the added attribute that they can also be charged directly from the electricity supply network.

Risks of working with electric vehicles and hybrid electric vehicles

Garages and recovery operations will be familiar with vehicles having 12 or 24 volt electrical circuits but Electric vehicles and hybrid electric vehicles use significantly higher currents. They operate at up to 650 volts DC (direct current). DC voltages above 150 volts are hazardous in dry conditions, and contact with 600 volts DC is likely to be fatal.

Therefore, there is a real risk of electrocution if the hazard is not appreciated and controlled. The battery systems store significant amounts of energy, sufficient to move a one ton vehicle more than 50 miles. Should this power system be short circuited or suddenly released, it could cause:

• Significant damage;
• Fire;
• Explosion.

There is also a risk that the batteries could explode and/or release harmful and toxic chemicals if not maintained and handled in accordance with the manufacturer’s instructions. There are substantial differences in the designs of electric vehicles and hybrid electric vehicles from different manufacturers. Having information specific to the manufacturer and the vehicle being worked on is important in identifying what actions are necessary to work safely.

Electric vehicles and hybrid electric vehicles introduce hazards into the workplace in addition to those normally associated with the repair and maintenance of vehicles. These include:

• High voltage components and cables capable of delivering a fatal electric shock;
• Stored electrical energy with the potential to cause explosion or fire;
• Components that can hold a dangerous voltage even when vehicles are “off”;
• Unexpected movement of electric motors or the vehicle itself, due to magnetic forces within the vehicle and its systems;
• Heavy, bulky and awkward to handle components. High voltage batteries are several times heavier than conventional batteries, so lifting aids and devices are required to prevent musculoskeletal disorders;
• Explosive gases and harmful liquids which can be released if batteries are damaged, overcharged or incorrectly modified;
• Electric vehicles are silent when operated. There is a risk that people would be unaware of planned or unexpected movements;
• Hybrid vehicles can start their internal combustion engine automatically when the ignition is on and the vehicle detects that the battery has discharged to a level at which recharging is necessary;
• High electric currents in batteries and high voltage systems in electric vehicles can cause magnetic fields which can induce eddy currents in the human body;
• Risks arising from electromagnetic fields are therefore potentially dangerous for mechanics and others with active implants such as cardiac pacemakers. (Also see additional info).

Assessing risks

An assessment of the hazards and risks faced by workers will be required at one or more levels. A generic workplace assessment is likely to identify most of the issues covered in the general precautions outlined above. Specific assessments are based on the vehicle make and type, using information provided by the manufacturer, for a range of tasks involving that vehicle. For vehicle recovery operations there will be both a generic assessment alongside a dynamic assessment for each incident attended, taking into account details such as:

• Location;
• Damage;
• Accessibility;
• Other vehicles;
• End of life depollution hazards;
• Vulnerable people.

Working safely with electric vehicles and hybrid electric vehicles.

Additional skills and training will be necessary for people to work safely with electric vehicles and hybrid electric vehicles. The levels of competency required will vary based on the type of work that they are expected to do. An awareness of additional risks is likely to be all that is required for people who undertake vehicle sales or valeting.

However, those involved in repair and maintenance are likely to need a much greater level of competence to safely work with electric vehicles and hybrid electric vehicles. In addition to the training offered and supplied by the vehicle manufacturers, specific training leading to recognised qualifications is offered by organisations such as the Institute of the Motor Industry.

As with any risk assessment, personal protective clothing is always seen as a last resort. However, it will be required for working with electrical vehicles and it is important that the most suitable is selected and ensure that personnel wear it correctly and look after it.

Additional information

There has been some controversy that persons with cardiovascular electronic devices should avoid electric cars.

Researchers at the Technical University of Munich studied the effect of electrical fields on persons with cardiovascular electronic devices. Their study, which was published earlier this year, involved 108 different devices from seven manufacturers and measured electromagnetic effects that vehicle occupants would experience. The models included a Nissan LEAF, a Tesla Model S, a BMW i3 and a Volkswagen e-Up. The researchers looked at the electrocardiograms of participants and had them independently analysed by two cardiologists.

Ultimately, they found no clinically relevant impact on the operation or programming of the devices when participants were driving or sitting inside the vehicles — even under maximum acceleration when electromagnetic effects are the strongest.

There’s just one problem: charging. According to TUM researchers, people wearing a pacemaker should exercise caution around level-2 (240V) and level-3 (400V) charging stations, which utilize strong electric current. That includes the charging cable itself and even the car’s charging port.

The conclusion is that Electric Vehicles are safe for those with cardiovascular electronic devices and no restrictions on travelling in them are required. However, they should let another person plug and unplug the vehicle and stay away during the entire charging process. It is not advisable that persons with cardiovascular electronic devices work on Electric Vehicles.

Additional information on using electrical storage batteries safely.