At a media roundtable held at LG Energy Solution's newly opened Lansing plant on 22 August 2026, the company's North America president gave a blunter answer about solid-state batteries than the industry has offered all year.
"The problem with solid state is large-scale production," Robert Lee said. "If you're making very large form factors, most companies are struggling."
His timing estimate was sharper still: solid-state cells will appear in smartphones "probably a decade before you would see it in EVs".
Why the form factor is the whole argument
Solid-state announcements are made at cell level, and at cell level the technology works: a small pouch with a solid electrolyte can hit the energy densities the press releases quote.
Scaling that cell to the size a car needs is the hard part. A solid electrolyte must stay in intimate contact with the electrodes across the whole area of the cell, through charge cycles that make those electrodes swell and shrink. Small cells tolerate this; large ones develop voids, and voids become dead capacity and hot spots.
That is why a phone is the easier target, and why Lee's decade-long gap is a statement about which manufacturing problem gets solved first.
Set against what the Chinese makers have been claiming
TeslAnt has covered three solid-state roadmaps in the past month, and all three point at the same year:
| Company | Claim | Target |
|---|---|---|
| BYD | Six new solid-state patents filed | Pilot production 2027 |
| CATL | Pilot production line | 2027 |
| Geely | 500 Wh/kg cells, 1,000+ km range | Pilot deployment 2027 |
Lee named none of them, and did not need to. Geely's 500 Wh/kg claim, CATL's 2027 pilot line and BYD's patent filings are all pilot-stage commitments — and a pilot line is precisely the stage before the large-format problem he describes has to be solved.
The positions are less contradictory than they look. Everyone agrees small cells can be built now; the disagreement is how far it is from a pilot cell to a car battery. LGES puts that at roughly a decade rather than the three or four years the 2027 dates imply.
LGES is not sitting it out
This is not a company dismissing a technology it has no stake in. LGES plans an all-solid-state pilot line using a dry electrode process in the second half of 2026, and will ship sodium-ion samples to customers in 2027.
Its nearer-term bet is different, though: lithium manganese rich cells developed with General Motors, promising more than 400 miles of range from 2028 at lithium iron phosphate pricing, using considerably less nickel and cobalt.
What this means for European Tesla buyers
LGES is a Tesla supplier. It builds cells for Tesla at Nanjing, and from August 2027 its Lansing plant supplies the LFP cells for Megapack 3 under a $4.3 billion contract. So this is a read on Tesla's own supply chain, not commentary from outside it.
Tesla's cell strategy currently runs through 4680 cylindrical cells and LFP, with LFP lines in Nevada and cathode production in Texas due this year. Nothing in that plan depends on solid-state arriving.
For a European buyer, the practical use of Lee's estimate is purchase timing. Waiting for a solid-state Tesla is not a strategy: on this account the cell that reaches a car is a 2030s component, and a European delivery would come later still than a Chinese or American one.
The second read-across is industrial. Europe's cell plants are being tooled now, and the chemistry they commit to is a decade-long bet. If large-format solid-state really is ten years out, European capacity built around LFP and high-manganese chemistries is aimed at the right target; if the 2027 dates hold, it is aimed at the previous generation. Either way, the number to watch is not energy density in a laboratory cell — it is the size of the cell that number was measured in.