Second-life EV batteries

Redwood Materials, Moment Energy, Nissan Motor Co., General Motors, Connected Energy and B2U Storage Solutions are active in the field. Their work spans repurposing retired batteries, stationary storage systems, safety controls and project deployment. Eco Stor As. also develops stationary storage using complete EV battery packs, while the companies differ in scale and technical approach.

Redwood Materials, Moment Energy, B2U Storage Solutions and Eco Stor As. are identified as startups active in second-life batteries. Moment Energy has developed a certified battery-management system and showcased containerized storage; B2U began commercial operations at a Texas project in September 2026. These examples point to activity in controls, manufacturing and grid-connected deployment.

Shaqra University and Multimedia University published a data-driven assessment framework in 2026, while University of Zilina and Kaunas University of Technology studied equivalent-circuit models in October 2026. Stanford University also studies used-capacity valuation and degradation prediction. Recent research concentrates on health estimation, grading, safety and matching batteries to stationary applications.

Funding data lists $104,614,629 across 25 grants since 2020 and 7 reported rounds totaling $18,827,837,889. These are tagged-field aggregates rather than a clean measure of capital invested only in dedicated second-life battery projects. The round total may include broad company or infrastructure financing, so it should be interpreted with that scope in mind.

Moment Energy announced a $40 million Series B in May 2026 to scale its second-life battery energy-storage business. Rebaba announced a $4.6 million seed round in September 2026 to expand storage systems using repurposed EV batteries across Europe. These announcements indicate financing interest in both North American manufacturing and European project expansion.

Eco Stor As. holds 4 patents and Redwood Materials holds 3, the highest counts among the listed patent holders. Overall patent activity declined 50% in the defined 24-month window. Other named holders include Hitachi Ltd. and B2U Storage Solutions, each with 1 patent, alongside several organizations with single listed patents.

Recent developments include Moment Energy’s UL 60730-1-certified battery-management system in May 2026 and B2U Storage Solutions’ Texas project, which began commercial operation in September 2026 and delivers 28 MWh of grid services. Research has also advanced battery grading, health prediction and equivalent-circuit model validation, addressing technical barriers to reliable reuse.

Pack-level reuse keeps complete battery packs intact, while module-level refurbishment replaces or selects modules and cell-level reassembly rebuilds systems from qualified cells. Battery testing and grading determines which pathway fits a battery’s condition. Controls and safety integration then supports stationary operation. Each step can improve fit for a target use, but adds testing, integration or handling requirements.

The United States leads with 2,851 documents, followed by Germany with 1,048 and the United Kingdom with 989. Japan, France and China also show substantial activity, with 918, 736 and 700 documents respectively. These figures describe activity in the dataset, not deployment capacity or market share.

The listed applications include grid-scale storage, commercial and industrial storage, residential backup, renewable energy integration, and off-grid and remote power. Grid-scale storage has 207 associated documents, while residential backup has 150 and off-grid and remote power has 105. Actual suitability depends on battery condition, system controls and the operating demands of the application.