A battery too degraded for a car's range needs can still cycle happily for a decade in a stationary grid-storage role with lighter demands.
usable_capacity(t) = capacity_0 * (1 - degradation)
repurpose if capacity > 70%
- Retired packs arriving — EV battery packs retired once they drop below ~80% original capacity.
- Storage rack sites — stationary-storage bays available to receive graded packs.
- Health-grading accuracy — how precisely each pack's remaining capacity and safety are assessed before reuse.
- Repurposing throughput — how fast graded packs are wired into a rack and put back into service.
Second-life battery farms already store solar power for grids at a fraction of new-battery cost, extending a pack's useful life by another 5-10 years.