Panasonic Energy said on June 12 that it is exploring converting part of its De Soto, Kansas cell factory from EV batteries to stationary storage cells aimed at data-center customers, with conversion-line production targeted for the third quarter of 2029. First sample cells from the converted lines are expected in mid-to-late 2028 or early 2029.
The De Soto plant is the marquee piece of US lithium-ion manufacturing capacity built on the EV thesis. It opened in July 2025, was sized for about 32 GWh of annual cell output once fully built, and is currently running at roughly half capacity with four of a planned eight production lines installed. The site has been targeting around 4,000 employees at full ramp.
In a statement provided to local press, Panasonic Energy said it is “constantly evaluating new opportunities” and that, in addition to meeting existing EV battery customer commitments, it is “exploring options to use some of our U.S. production capacity to address the growing need for data center energy storage.” The company would not name prospective data-center buyers or say how lines would be allocated between EV and stationary cells.
The trigger is two-sided. EV cell offtake has come in below the volumes assumed when the plant was scoped, and the foreign-entity-of-concern provisions in the One Big Beautiful Bill Act limit which competitors can compete for the IRA-eligible US demand pool. That combination leaves Panasonic with US capacity, a clean ownership structure, and softer-than-modeled EV pull. Data-center BESS demand fills the gap.
This is not an isolated move. Ultium Cells, Samsung SDI, SK On, and LG Energy Solution have each signaled or executed similar EV-to-stationary repointing in the last twelve months. Panasonic is the cleanest case because the De Soto plant is wholly owned, IRA-aligned, and not yet fully built out, so the conversion can be planned into the back half of the buildout rather than retrofitted onto fully tooled lines.
For the US lithium-supply thesis, the read is straightforward. Capacity built on EV assumptions is being rerated to the AI and grid-storage demand stack. The cells will still get made, the offtake mix changes. Watch for the first named hyperscaler or utility BESS contract attached to De Soto output, and for whether Panasonic uses the conversion as cover to expand the plant past its original 32 GWh sizing.