High-Power Medium- and Heavy-Duty Electric Vehicle Charging

NREL's leading-edge research to develop megawatt-scale charging systems is advancing the affordability and reliability of medium- and heavy-duty electric vehicles (EVs). 

Our research enables faster, cost-effective charging and identifies managed charging solutions to support the nation's power grid. Truck charging stations of the future must provide reliable, high-power charging at an estimated capacity of 1 MW or more.

Electric Vehicle Charging Characterization

High-power charging profiles can vary greatly between electric vehicle supply equipment (EVSE) and EV manufacturers. Understanding these differences will be critical for devising both control and energy storage integration solutions to lower the cost of charging.

To further this understanding, NREL is working to:

• Capture EV high-power charge profiles from commercially available EVs and EVSE under differing operating conditions to fully quantify charging loads seen by the grid
• Characterize and analyzes EV fleet charging data
• Identify several barriers to reliability for EVSE.

These insights advance the state of high-power charging and benefits project partners by improving interoperability, charging reliability, and overall performance of EVs and EVSE.

Advanced Architectures for Electric Vehicle Charging Hardware Systems

NREL is contributing to the advancement of interoperable, reliable, and fast charging hardware systems by designing and operating alternative site architectures for DC charging. Researchers are developing solutions for DC hubs with centralized power conversion equipment integrated with the grid and DC/DC chargers to reduce equipment costs and increase EV charging efficiency. The insights generated by this effort will provide a pathway for industry to better understand the necessary development stages for a high-power DC-coupled charging hub.

As part of this effort, NREL researchers will:

• Conduct reviews of different station power architectures for both AC-hub and DC-hub approaches
• Validate the DC charging hub hardware, including DC-DC converters and DC-AC inverters, and software systems within the station and with the grid at megawatt scale
• Develop low-power, control-hardware-in-the-loop and high-power, power-hardware-in-the-loop experimental platforms to better understand scalability challenges
• Determine station design requirements for DC bus distribution and site energy management systems
• Design and demonstrate practical controllers to facilitate flexible sizing of charging hubs serving light-, medium-, and heavy-duty vehicles.

Electric Vehicle Charging Standards

NREL researchers are developing new charging standards for EVs across vehicle types and applications that require higher charging power while supporting the grid. NREL actively supported the development of a new high-power charging standard for medium- and heavy-duty vehicles—called the Megawatt Charging System (MCS)—and continues to assist with its refinement. MCS will facilitate charging capacity up to 3.75 MW—seven times higher than the current light-duty fast charging peak of 500 kW.

EV charging equipment evaluation will ensure the new standard is interoperable, allowing multiple manufacturers to design and build compatible components. Interoperability is critical for broad, consistent reliability of charging stations and gives EV manufacturers confidence in station compatibility as new models come to market.

Site Planning and Design

NREL researchers assess enroute charging, as well as associated planning, infrastructure, operation, and maintenance options, for on-road and non-road vehicles, aviation, rail, and marine applications. Site planning and design help ensure that sites are adequately built for expected demand, reducing wasted effort and costs. A well-planned and designed site can be built and operated more efficiently.

NREL's EV infrastructure tools help researchers, industry, fleet, and charging site operators develop customized EV infrastructure design and optimization strategies, conduct analyses of proposed refueling centers and depot charging leveraging utilization of the current fleets, and determine potential grid impacts.

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