Cost-Effective Integration of Second-life EV Batteries with Solar PV Systems for Commercial Buildings
Developing battery management system technologies, algorithms, and operation strategies to extend the second-life of EV batteries.
San Diego State University Foundation
Recipient
San Diego, CA
Recipient Location
39th
Senate District
79th
Assembly District
$2,056,221
Amount Spent
Active
Project Status
Project Update
San Diego State University Research Foundation (SDSURF) has deployed its energy storage system at the UCSD Warehouse; it has a nominal capacity of 372 kWh and uses second-life Nissan Leaf battery packs. The demonstration site is used to validate the ability of second-life electric vehicle (EV) batteries when paired with a solar photovoltaic (PV) system, to provide building resiliency and load-shifting services for small- and medium-sized commercial buildings. The site has been in operation since May 2024 and will last until the end of 2025. SDSURF is also working with Oberlin to install a new energy storage system with 550 kWh capacity, using the energy management system (EMS) developed by SDSURF, to compare the performance of new and second-life EV batteries.
The Issue
California has the goal of 5 million zero-emission vehicles on the road by 2030, meaning that over the next few decades, a large number of used electric vehicle (EV) batteries will need to be recycled. EV batteries typically retire from their first life when their performance decreases to 70-80 percent of their initial capacity. Our research has demonstrated that second-life batteries paired with solar photovoltaics (PV) and demand response could be economical. Moreover, lower-cost second-life EV batteries may enable small businesses with buildings under 30,000 square feet to install PV-battery systems and may lower energy costs for California ratepayers.
Project Innovation
This project pairs second-life EV batteries with a solar PV system and develops key technologies to quickly identify battery health and optimize usage. These key technologies include developing control and operation algorithms to enable 1) proactive maintenance, 2) predictive thermal management, 3) active cell balancing, and 4) dynamic demand response management. Together, these technological advancements extend the life of the repurposed EV batteries and lower the cost to California ratepayers. The goal is to ensure that second-life EV batteries will last for a minimum of 10 years as part of a grid storage application with a degradation rate of 3% or less annually.
Project Goals
Characterize the Degradation Rate of Second-life EV Battery Cells.
Validate the Second-life EV Battery Paired with Behind-the-Meter Solar PV.
Develop and Demonstrate Technologies, Algorithms, and Operation Strategies as it relates to second-life EV batteries.
Project Benefits
The project is developing battery management system technologies, algorithms, and operation strategies that enable second-life EV batteries to last for a minimum of 10 years with a degradation rate of 3% or less annually. The battery management systems and second-life batteries will be tested at two pilot test facilities where the battery management algorithms and hardware will be deployed. The technological developments from this project will increase the versatility, lifetime/durability, and efficiency of second-life EV batteries while also lowering the total cost of these systems.
Affordability
Affordability
This project will help commercial customers significantly reduce their electricity bills through novel battery energy storage system operating and sizing algorithms, thus promoting the deployment of lower-cost energy storage systems.
Reliability
Reliability
This project is demonstrating and validating that the second-life EV battery when integrated with solar PV can operate reliably, support grid needs, and provide energy resilience to commercial buildings to serve their critical energy needs and requirements.
Key Project Members
Chris Mi
Distinguished Professor
San Diego State University
Subrecipients
Tech Partner
The Regents of the University of California on behalf of the Riverside campus
Tech Partner
The Regents of California, San Diego
Smartville, Inc.
Protection Design and Consulting
Oberlin Realty LLC
MEOS, Inc
Rizza Engineering
Match Partners
The Regents of the University of California on behalf of the Riverside campus
The Regents of California, San Diego
San Diego State University
