BYD has filed a new patent for a solid-state battery with a sulfide electrolyte – one of the most promising next-generation technologies for electric vehicles. The main idea behind solid-state batteries is to replace the liquid electrolyte with a solid material. This potentially allows for increased energy density, improved safety, and reduced charging time. Sulfide electrolytes are considered particularly promising due to their high ionic conductivity, which is close to that of classic lithium-ion batteries.
BYD's patent describes a new electrolyte structure and methods to improve battery stability. This is a critically important issue for sulfide solid-state systems: the material is sensitive to moisture and difficult to mass-produce.
It is especially important that this is no longer about laboratory experiments. According to China EV100, China plans to begin pilot production of solid-state batteries by approximately 2027. BYD, CATL, Gotion, SAIC, and other major industry players are participating in the race.
Currently, most electric vehicles use lithium-ion batteries with liquid electrolytes. They are cheaper and technologically well-developed but have limitations in energy density and risks of thermal runaway. This is why the industry views solid-state as a potential "next leap" in EV technologies.
The problem is that mass production of such batteries remains extremely challenging. Companies are still struggling with material degradation, production costs, and operational stability under high loads. Many experts believe that full-scale industrial implementation could take several more years.
But China is clearly trying to accelerate the process. And if BYD and other local manufacturers are the first to bring solid-state batteries to the mass market, it could seriously shift the balance of power in the global battery industry.