NREL Team Investigates Secondary Uses for Electric Vehicles Batteries

The U.S. Department of Energy’s (DOE) National Renewable Energy Laboratory (NREL), industry and academia are teaming to give lithium ion batteries from electric vehicles (EV) a “second life.” NREL’s partner is an industry-academia team led by the California Center for Sustainable Energy (CCSE).

Possible secondary uses for lithium ion (Li-ion) batteries include residential and commercial electric power management, power grid stabilization to help provide reliable electricity to users, and renewable energy system firming — which in this case involves using batteries to make power provided to the grid by variable resources such as wind energy and solar power more useable. To date, no one has comprehensively studied the feasibility, durability, and value of Li-ion batteries for second-use applications.

The project will begin with a comprehensive technical and economic analysis addressing all aspects of a battery’s lifecycle in search of the best second-use strategies, followed by a comprehensive test program to verify findings, particularly battery lifetimes. For the field test, researchers will deploy aged electric car lithium ion batteries at the University of California (UC), San Diego’s campus-wide electric power grid. The results of the study will:

Provide validated tools and data on battery life to industry for battery reuse
Recommendations for EV battery design and manufacturing practices
Identify the necessary regulatory changes to encourage secondary battery use
Assess the economic benefit of second uses

The cost of Li-ion batteries also currently affects the affordability of EVs for consumers. Researchers will do a technical and economic investigation to see if the potential for reusing Li-ion batteries could lead to consumers obtaining a cost credit for the remaining value of a used battery, potentially offsetting a portion of the initial cost to the EV buyer. It might be the case that while a battery no longer has sufficient power for an EV, it still has the capability to meet the needs of other less demanding applications.

Allocating used electric vehicle batteries to second-use applications also could benefit the environment by delaying the recycling or disposing of batteries, and by supplying a service that improves the efficiency and cleanliness of other industries.

The CCSE project team includes the UC Davis’s Plug-In Hybrid Electric Vehicle Research Center, the UC Berkeley, Transportation Sustainability Research Center (TSRC), UC San Diego Strategic Energy Initiatives, San Diego Gas & Electric, and AeroVironment.

The NREL award to the CCSE team leverages an ongoing UC Davis-CCSE-TSRC study funded by the California Energy Commission on the repurposing of used EV batteries for home energy storage. The total budget for the NREL-CCSE second use battery project is approximately $1.3 million with 51 percent of the funding coming from CCSE and its partners.

This activity is sponsored by DOE’s Office of Energy Efficiency and Renewable Energy. NREL’s cross-cutting capabilities and expertise in energy storage, advanced vehicles, grid interfaces, system analysis, and solar and wind energy will provide overall project direction and critical assessment.

NREL is the Department of Energy’s primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for DOE by The Alliance for Sustainable Energy, LLC.