BYD has taken another step toward next-generation electric vehicle battery technology by filing a new patent for a sulfide-based solid-state battery component, as China’s leading battery makers accelerate plans for pilot production by 2027.
According to reports published by Sina, the newly filed patent focuses on a “composite solid electrolyte membrane and its preparation method, solid-state battery, battery pack and electrical device.” The filing was published under CN121983643A by China’s National Intellectual Property Administration.
The latest development highlights the intensifying competition among Chinese EV and battery manufacturers to commercialize safer, higher-density solid-state batteries that could reshape the future of electric mobility.
BYD Patent Focuses on Electrolyte Innovation
The patent outlines a composite electrolyte structure that combines inorganic solid electrolyte particles with a polymer electrolyte fibre coating network. The design includes both large and small inorganic particles integrated into a polymer matrix containing lithium salt.
According to the filing, the fibre-network structure wraps around portions of the inorganic electrolyte surface to improve ionic conductivity and strengthen the mechanical stability of the electrolyte membrane.
Although the patent reveals important structural details, it does not disclose several key performance indicators typically associated with solid-state batteries. There are no official figures related to energy density, charging speed, cycle life, production costs, or commercial launch timelines.
The filing also does not mention lithium-metal anodes, vehicle integration systems, or pressure-management technologies often linked with sulfide all-solid-state battery platforms.
BYD Says Development Reached “Critical Breakthrough Stage”
Earlier in April 2026, BYD Chief Scientist Lian Yubo stated that the company’s all-solid-state battery research had entered a “critical breakthrough stage.”
However, he acknowledged that major hurdles still remain before large-scale commercialization becomes possible. These challenges include manufacturing complexity, production yield consistency, cost reduction, and solid-solid interface stability.
Lian also identified lithium dendrite suppression as one of the biggest technical obstacles facing the industry.
He emphasized that battery companies must focus on complete system-level development instead of optimizing only individual battery cells.
BYD had previously hinted at pilot-scale deployment around 2027. The company is also reportedly developing third-generation sodium-ion batteries capable of achieving up to 10,000 charging cycles.
China’s Solid-State Battery Competition Intensifies
China’s battery sector is rapidly moving toward advanced solid-state battery production, with several major players unveiling high-capacity prototypes.
CALB recently introduced a 60Ah all-solid-state battery prototype with energy density exceeding 450 Wh/kg. Meanwhile, Chery announced development of a 60Ah solid-state battery targeting 400 Wh/kg, with vehicle integration tests expected by 2027.
Industry giant CATL has also disclosed sulfide-based solid-state battery patents and similar pilot production timelines.
In addition, GAC Group revealed that its automotive-grade solid-state battery cells above 60Ah have already entered small-batch validation production.
As competition heats up, the race toward commercial solid-state EV batteries is becoming one of the most closely watched technological battles in the global automotive industry.
