While Toyota spent over a decade preaching the gospel of solid-state batteries like a corporate messiah, Honda quietly walked into the workshop and flipped the power switch. In January 2025, Honda officially operationalized a massive 27,400-square-meter production line at its Sakura plant in Tochigi Prefecture. That makes Honda the first automaker on earth to drag solid-state battery technology out of press releases and onto an actual factory floor.
This is a 43-billion-yen ($290 million) facility, backed partly by Japan’s Green Innovation Fund. The building was erected by spring 2024, packed with machinery before the year ended, and immediately aimed at stealing Toyota’s long-hyped head start.
The real engineering magic boils down to a process called roll pressing. Instead of traditional welding, Honda literally squishes the battery cells during assembly. This crushing action squeezes out micro-air pockets, forcing the solid powder electrolyte into intimate, uninterrupted contact with the electrodes. The result? Higher energy density, minimal power loss, superior efficiency, and lightning-fast manufacturing. To prevent lithium dendrites, Honda developed a paper-thin polymer film layer. It’s thin enough to let electron traffic flow freely, yet tough enough to stop dendrite spikes dead in their tracks.
Honda’s master plan isn’t limited to family commuters, either. The brand wants solid-state power in its motorcycles, commercial trucks, and aircraft, aiming to recreate the ubiquity of its legendary internal combustion engines. Scaling production up across everything that moves is classic Economics 101: build massive volume to slay astronomical production costs.
Yet, in a twist of delicious corporate irony, Honda achieves this technological milestone right as it prepares to pull its only current EV, the Prologue, from showroom floors after 2026. Toss in the murky future of its Sony joint venture and 0 Series lineup, and Honda finds itself with zero mainstream EVs on the near horizon while spending billions on next-gen tech. Still, with pledges for full carbon neutrality by 2050 and 100% electric production by 2040, solid-state remains the holy grail.
Honda President Keiji Otsu famously dubbed the breakthrough a “game-changer in the EV era”, a phrase automotive executives drop so relentlessly it has lost all human meaning, though this time, Honda might actually mean it.
