Ron Walli, Argonne National Lab
Widespread demand for electric vehicles could hinge on batteries that can be charged in minutes instead of hours, and researchers at the Department of Energy’s (DOE) Argonne National Laboratory are on the road to making that happen.
“Our goal is to give drivers an experience they’re familiar with, and that is being able to pull into a station, charge their battery and be on their way in about 10 minutes,” said Argonne chemist and battery expert Ira Bloom, who sees this happening in the near future. DOE’s Vehicle Technologies Office is demonstrating its commitment to this effort through a $15 million funding opportunity announced Oct. 24.
The migration to plug-in electric vehicles, or PEVs, which are considerably more efficient than their internal combustion engine counterparts, would also help the United States gain energy independence, researchers noted in a recent study. First, however, researchers must overcome a number of challenges that start with the development of new battery materials, design, and cost. But there are other obstacles as well.
Infrastructure, economic feasibility, public and stakeholder acceptance and power demands placed on utilities are key considerations as this DOE initiative pools the talent and resources of Argonne National Laboratory, Idaho National Laboratory (INL) and National Renewable Energy Laboratory (NREL). The goal is to identify and fill gaps hindering the commercialization of extreme fast charging, defined as 350 kilowatts or more of power.
Current types of charging start at Level 1 with about 1 kilowatt, or identical to a regular electrical outlet; Level 2 at about 3 kilowatts, or what’s needed for residential dryers and water heaters; and direct current, which starts at about 50 kilowatts. Extreme fast charging would start at 350 kilowatts or 350,000 watts. Charging times to add 200 miles of range to a fully depleted battery range from about 40 hours (Level 1) to about 15 minutes (extreme fast charging).
Argonne, nationally renowned for its capabilities in battery testing, materials, and development, has a prominent role in this effort, and Bloom, who manages the Battery Post-Test Facility and Electrochemical Analysis and Diagnostics Laboratory (EADL), is a key player.
To be successful, Bloom and colleagues use a methodical approach in which they first identify and characterize the nature of the fast charge problem. This requires the expertise of EADL researchers who perform electrochemical transport properties tests on materials carefully chosen for their potential. After evaluating and understanding their transport properties, researchers model the material in prototype cells and examine the effects of fast charging.
Since the 1970s, Argonne’s EADL has provided reliable, independent and impartial evaluations of battery performance and life. Using this lab, researchers can test everything from small cells for consumer electronics to full-size vehicle batteries. Special environmental chambers enable researchers to test batteries over a wide range of temperatures, and they’re also able to accelerate the performance degradation process.
Meanwhile, the Battery Post-Test Facility provides post-mortem information about what happens as batteries age. It helps researchers understand how chemistries and materials change and degrade, which enables them to develop technologies that increase battery life. Researchers also use this facility to develop strategies that ensure safety as power levels increase.
Unfortunately, there are no shortcuts as researchers work to optimize cost, complexity and power density.
“Managing heat and developing materials able to withstand high temperatures are constant challenges because heat shortens the life of materials,” Bloom said. “With conventional materials, we can only put so much current into a battery because it creates tremendous heat.”
Researchers from INL will join Argonne in battery testing and electrochemical characterization while NREL researchers will conduct thermal characterization tests and work with Argonne on battery cell modeling. Argonne researchers will also conduct post-test characterization.
In non-battery areas of the extreme fast-charging initiative, Argonne’s Andrew Burnham and Thomas Stephens are studying economic feasibility and outreach to utilities and stakeholders; NREL is looking at vehicle integration and speeding recharging times, and INL is tasked with infrastructure. The three laboratories’ findings are featured in the current edition of the Journal of Power Sources.
A study by Burnham, Stephen, and colleagues found that public fast charging could increase electric vehicle demand by allowing consumers who don’t have access to residential or workplace charging to use it as their primary means of charging. In fact, a study by Burnham, Stephens, and colleagues found that in areas where consumers had access to fast charging, annual EV miles traveled increased by more than 25 percent.
While fast charging could also make long-distance travel far more practical, there are many other considerations such as high investment costs for charging stations, utility rate structures penalizing low-utilization stations and the need for safety and well-defined codes and standards.
Researchers noted in their paper that the grid’s ability to support extreme fast charging is a key consideration, especially in areas of aging infrastructure. Other issues that need to be addressed include location-specific codes, coordination across multiple public utilities, grid harmonics and voltage stability, distribution feeders and appropriately sized transformers.
To advance the technology, establishing corridors along popular routes in some of the nation’s big cities would provide a test bed for the technology, increasing consumer confidence and acceptance of this technology. Fleet owners could also set up charging stations at their bases and at strategic locations.
From Burnham’s perspective, public acceptance will increase as researchers continue to improve designs and lower costs. “Technically, we can do this,” he said. “The challenge will be to make the technology cost-effective, but working with partners at national labs and industry we have identified the gaps for the successful deployment of extreme fast charging.”
Funding is provided by DOE’s Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Office.
Filed Under: Energy storage