Honda has established EV partnerships with General Motors and Sony, but the automaker is going it alone on solid-state battery tech.

Honda plans to invest 43 billion yen ($290 million at current exchange rates) to build a demonstration solid-state battery production line in Sakura, a city in Japan’s Tochigi Prefecture, slated to open in spring 2024, according to a report from Ars Technica based on comments from executives during a media roundtable at Honda’s Tokyo headquarters.

Shinji Aoyama, Honda’s global leader of electrification, said the automaker hopes to get solid-state batteries into production cars by the end of the decade, likely 2028 or 2029. The goal for the technology, which is also being pursued by other automakers and battery firms, is increased range and shorter charging times.

2024 Honda Prologue2024 Honda Prologue 

Honda global CEO Toshihiro Mibe reportedly said at the roundtable that the automaker hasn’t decided which vehicle will be the first to get solid-state batteries, but added that he would like to see them used in motorcycles as well as cars. Honda plans to launch 10 new electric motorcycles globally by 2025—including some for the United States—and in 2021 it joined a coalition of Japanese motorcycle makers to develop battery-swapping standards for bikes.

But before solid-state batteries can go into any vehicles, Honda researchers need to solve a longevity issue. The automaker has found that its experimental solid-state cells are particularly susceptible to lithium dendrites, spikes of material that form over time and can cause short circuits during charging.

Honda’s solution is to add layers of fabric sandwiching the solid electrolyte (which is where the term “solid state” comes from) to prevent dendrites from forming without sacrificing battery performance—in theory, at least. The materials are combined with a roll press that also allows for thinner layers, Honda claims. This process still needs testing before the Japanese pilot production line opens in 2024, but if successful it would be scaled up to other global facilities—perhaps including Honda’s planned Ohio battery plant

Other automakers—such as BMW and Ford—are testing solid-state battery tech developed by outside startups, but Honda isn’t the only one developing the tech on its own. Nissan also sees solid-state batteries as the key to making electric SUVs and pickups viable, and it’s working on its own proprietary solid-state cells.

While Honda is keeping this research in-house, it plans to roll out a series of EVs developed with partners. First comes the 2024 Honda Prologue SUV, which is built on GM’s Ultium component set. Honda is also partnering with GM to develop a shared architecture underpinning potentially millions of affordable EVs, arriving by 2027. They will feature a smaller cell format than what’s used in the Prologue, the Acura ZDX, Hummer EV, Cadillac Lyriq, and many others to come.

Honda hasn’t yet detailed how much tech will be shared with the Honda-Sony joint venture announced earlier this year, but the first Honda-Sony EVs will be built in 2025 in North America at a Honda facility.

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