Relay Requirements For Electric Vehicle Charging Stations

December 04, 2012
By Anonymous

For all their promise, electric vehicles won’t really hit the roads in any great numbers until charging stations become more readily available. Fortunately, the creation of a charging infrastructure is underway based on three different types of charging stations. Here’s a look at these stations and why they need the right kind of DC relays to enable safe, effective electric vehicle charging:

Three Charger Levels

There are three different levels of charging stations, which differ in their allowable charging voltage, the complexity of their installation and the amount of time they take to charge.

  • Level 1 Charging Station – 120VAC, 16A (1.92kW).  Compatible with ordinary household electrical outlets, the Level 1 station normally takes 8 to 12 hours to fully charge an electric vehicle. It provides AC energy directly to the vehicle’s on-board charging system, which has an internal AC/DC converter. Because Level 1 stations are “plug and play” with regular residential outlets, they can be installed in the home without professional help.
  • Level 2 Charging Station – 208 to 240VAC, 12 to 80A (2.5 to 19.2kW).  Level 2 stations provide a fast charge time of three to six hours. They, too, provide AC energy to the vehicle’s on-board charging system where conversion to DC energy is done. Because of safety concerns related to their higher voltages, Level 2 stations must be permanently installed by a licensed electrician. These stations can be used either indoors or outdoors and are suitable for public or private installations.
  • Level 3 Charging Station – 300 to 600VDC, 400A Max. Level 3 charging stations, which are also DC fast chargers, provide DC electricity to the car’s battery. Because AC-to-DC conversion is not required, they take only 20 to 30 minutes to charge the vehicle. This method of electric vehicle charging will dominate the public charging infrastructure, serving as “gas stations” for electric vehicles.

Electric vehicle charging typically requires two different types of high-capacity DC relays. Our EP Relays would typically be used in the charging station itself, while our EV Relays can be implemented within the automotive circuitry.

Relays For Electric Vehicle Charging

High capacity DC relays play a crucial role by cutting off current when the vehicle is connected or disconnected to an electric charger. Typically, these relays will be implemented in both the charger itself and in the vehicle’s electrical system. For example, our EP Relay would typically be used within the design of the charging station itself. It features a hermetically sealed construction, with a hydrogen gas mix enclosed within a ceramic capsule to enhance arc reduction at high voltage and current values. An example of a relay well-suited for use on the vehicle would be our EV Relay. It offers the same features as the standard EP relay with a higher degree of reliability for automotive applications. In addition to current protection, relays also see use in battery monitoring systems. Our automotive-rated AQV and AQW relays, for instance, are used for battery management within hybrid vehicles. With their high switching speeds and electrical isolation, these relays are ideal for scanning battery cells. Download our guide to relays for electric vehicle applications.  For more information on relays for electric vehicles and charging systems contact Aiman Kiwan.