Its Electric...Is it safe?
Updated: Jun 11, 2020
An electric vehicle can be recharged from an external source of electricity (e.g., portable chargers, wall-mounted charging points, charging stations, etc), with the electricity stored in rechargeable battery packs driving the electric motors or traction motors for propulsion. As per Wikipedia, an electric vehicle charging station, also called EV charging station, electric recharging point, charging point, charge point, ECS (electronic charging station), and EVSE (electric vehicle supply equipment), is an element in an infrastructure that supplies electric energy for the recharging of plug-in electric vehicles.
Access to a convenient, safe, and reliable charging infrastructure at home, at work, and in public places is the major showstopper to large-scale EV adoption. The drivetrain, where the energy conversion from the batteries for propulsion occurs, includes the converter, electric motor, and transmission. The electric motor is driven by an electronic converter, which operates the conversion of the battery’s fixed dc voltage into an input to the motor based on the user inputs (e.g., acceleration or brake pedals)/driving conditions while controlling operating parameters. Auxiliary equipment not directly used for propulsion is also seen in the EV.
Hazards associated with EVs:
1. Chemical hazard- Associated with a given battery technology and stems from the potential chemical release of the battery’s reactive constituents, with which people may come into contact.Proper manufacturing techniques of the batteries with greater emphasis on quality is required.
2. Collision hazard-To prevent cutting high-voltage cables during collisions, flexible conduits should be used. The routing of high-current cables under the vehicle floor should also be considered to protect the cables from impact. The battery terminals should be located as far away as possible from each other to minimize possible contact during a collision.
3. Electric Hazard- A large amount of energy stored in batteries can result in high-energy release in the event of a fault. Energy stored due to the capacitance can also be large. Voltages greater than 30 Vac and 60 Vdc are generally considered harmful and defined as high voltages. Necessitating protection against direct and indirect contact with electrified equipment. Direct contact occurs when parts that are normally live become accessible to touch; indirect contact happens when a piece of equipment that is not normally live becomes energized because of the failure of its basic insulation.
EVs not undercharge are electrical systems isolated from ground. Thus, the risk of direct contact is exclusively due to contact with live parts. On the other hand, the risk of indirect contact is due to the occurrence of faults, which may expose people to the risk of simultaneously touching parts at different potentials. When the EV is being charged, people’s electrical safety is based on the electrical characteristics of the charger. A charger with a transformer provides necessary isolation galvanically separating the EV from the power source.
Checks can be performed before starting the charging process and during the charge, and the risk of electric shock under both normal operating conditions and in case of electrical and/or mechanical failure can be reduced. A greater degree of electric safety can be possible with a dedicated charging point, a 30-mA Residual Current Detector, and a ground-loop monitor to uninterruptedly control the continuity of the Protective earthing conductor .