“The technology of the future is changing business today” is an apt quote to define the changing technology in the automobile sector. With the advent of Electric Vehicles (EVs), a new dimension has emerged out, which demands modern equipments and infrastructure that involves huge financial investments over a significant time period. The need for charging station and the equipments involved in the installation are one such need that manufacturers are desperately looking at.
Charging equipment, henceforth denoted by “electric vehicle supply equipment” (EVSE) comes in two basic varieties:
The first, comprising “Level 1” and “Level 2” EVSE, operates using alternating current (AC), and can draw electricity directly from the local distribution system. All Battery Electric Vehicles (BEVs) and Plug-in Hybrid Electric Vehicles (PHEVs) carry an on-board inverter with limited capacity, to convert AC power to direct current (DC), which is required to charge the battery. The second variety, “Level 3” and above, uses DC charging, which bypasses the need for an inverter by charging the battery directly and can therefore deliver much more power. There is otherwise no relevant difference in the AC and DC charging process. Chargers in public or commercial locations, typically Level 2 and above may be standalone devices or stations comprised of multiple chargers.
Alternating Current Level 1, providing 1.4 kW of power for example, is simply a conventional wall socket, and requires no additional circuitry, aside from the adapters required to connect the EV to the socket. Level 1 charging can be used anywhere, although it takes place primarily at the EV owners’ homes.
Level 2 charging operates on the same upgraded 220-volt outlets, required by washing machines and clothes driers, and can easily be installed. More modern houses typically have these outlets, while older houses may require electrical upgrades. Depending on the home’s electrical infrastructure, this can involve upgraded circuitry, wiring extensions to reach the charging location, or, even in rare cases, an upgraded transformer. Level 2 charging can also be provided at workplace locations, other business locations (hotels, gas stations, private parking lots), and public locations. Level 2 charging starts at a power rating of 6.6 kW, increasing to 19.2 kW depending on the level of current that the
supporting circuitry can sustain. Most home Level 2 charging, and almost all commercial Level 2 charging, is limited to 6.6 kW because (a) the onboard inverter on most existing EVs cannot handle significantly more than this level38 and (b) boosting the current typically requires the installation of more expensive higher-capacity circuitry.
Because direct current charging bypasses an EV’s onboard inverter to charge the battery directly, it can deliver much higher levels of electrical power. This type of charger is commonly referred to as a Direct Current Fast Charger (DCFC) and is typically used only in commercial locations.
While studies demonstrate that consistently high DCFC usage can accelerate deterioration in battery capacity over time, capacity degradation for presents each charger type, its nominal power rating (in kW), the time taken to replenish the expected average daily usage, the time taken to replenish 100 km of charge and the miles of range added per minute of charging. Charging time is assumed to depend entirely on the power rating of the charger, although in practice, technical limitations on the battery, electrical supply, and inverter capacity (for AC charging) can add time to the process. It is assumed that the rate of charging is linear. This is a reasonable simplifying assumption, since the rate of charging does not diminish significantly until the battery reaches approximately 90% of capacity and most public charging sessions are used to partially recharge batteries rather than fully recharge them.
All in all there is a need to develop infrastructure for these charging stations proper standardisation and compatibility that too at a rapid rate to attract the customers who are conventional automotive buyers. These equipments although come with a very high initial investment are a need of the hour and will ensure EVs rule the markets in the future.