Panasonic Relays for EV Charging Stations

January 14, 2016
By Jeffrey Katz

The global adoption of electric vehicles underlines the need for quality relays and components to ensure a robust electric vehicle supply equipment (EVSE) infrastructure. According to the International Energy Agency, the number of electric vehicles worldwide in 2020 is projected to grow to 20 million. As the market expands, the demand for more electric vehicle charging stations is becoming increasingly necessary.

As of the end of 2015, there were over 90,000 slow charging points as well as over 15,000 fast charging points worldwide. This exponential rise is expected to continue with an estimated 3.8 Million charging stations in service by 2020.

Each charging point requires multiple relays to properly function. At the current rate of rise, this would equate to tens of millions of relays being employed in charging stations worldwide by 2020.

There are three charger levels exist for electric vehicles, each of which vary in charge voltages, charge duration, and complexity of installation. Let take a look at each in greater detail:

  • Level 1 Charging Station – 120VAC, 16A (1.92kW). Compatible with ordinary household electrical outlets, the Level 1 station normally takes 8 hours to get around 40 miles of travel in 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 can provide a fast charge time of 20 minutes which can get between 50 to 70 miles. They, too, provide AC energy to the vehicle’s onboard 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, 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 completely. This method of electric vehicle charging will dominate the public charging infrastructure, serving as “gas stations” for electric vehicles.

With the various charging levels in mind, there are four different functions for relays to be used in this application:

electric vehicle charging application

  1. Safety Cutoff on the AC Side
    AC Power Relays are used as safety measures to protect the power supply system by cutting off the circuit in the event of abnormal currents in the power grid.
  2. Insulation Detection for Battery Inside the Inverter
    If the insulation in a station deteriorates, a ground-fault current passes when the relay is turned on, and a sensor detects the current. With fast switching speeds and high electrical isolation, high load voltage type PhotoMOS relays are ideal for use with quick charger stations.
  3. Safety Cutoff on the DC Side
    These relays are required as a safety measure in the event of a defect in or malfunction of the battery or system. The Panasonic EP relay series features a hermetically sealed construction, with a hydrogen gas mix enclosed within a ceramic capsule to enhance arc reduction at high voltages and high current values. This can be one of the most demanding requirements for a DC power relay.
  4. Signal Control for IC Card Activation
    For charge points that require the use of IC cards for charge control, low on-resistance type PhotoMOS Relays with voltages around 30V to 60V are ideal.

For more information on Panasonic Relays for EV Charging Stations contact us today or visit our Relays Page.