BYD has filed a new patent related to solid-state battery technology, expanding its research efforts in next-generation battery systems amid intensifying competition among Chinese battery manufacturers, according to a report by Sina.
The patent filing, identified as CN121983643A and published by China’s National Intellectual Property Administration, covers a “composite solid electrolyte membrane and its preparation method, solid-state battery, battery pack and electrical device.”
According to the filing, the patented structure combines multiple inorganic solid electrolyte particles with a polymer electrolyte fibre network coating designed to improve ionic conductivity and mechanical strength.
The document describes the electrolyte layer as containing both larger and smaller inorganic electrolyte particles embedded within a polymer matrix and lithium salt structure.
The polymer electrolyte is wrapped around portions of the inorganic electrolyte surface in a fibre-like network, according to the filing.
The patent does not disclose details including energy density, charging speed, cycle life, manufacturing costs or commercialization timelines. It also does not reference lithium-metal anodes or pack-level system designs commonly associated with sulfide-based all-solid-state battery architectures.
In April 2026, BYD Chief Scientist Lian Yubo said the company’s all-solid-state battery programme had entered a “critical breakthrough stage,” while noting that engineering complexity, manufacturing yields and cost reduction remained major challenges for commercialization.
Lian said key technical obstacles include maintaining stable solid-solid interfaces and suppressing lithium dendrite formation.
He also said the industry should prioritize full-system battery development rather than focusing solely on individual cell optimization.
BYD previously indicated pilot-scale deployment plans around 2027 and has also been developing third-generation sodium-ion batteries targeting up to 10,000 charging cycles.
The latest filing comes as several Chinese battery and automotive companies accelerate solid-state battery development efforts.
In March, CALB unveiled a 60 Ah all-solid-state battery prototype with energy density above 450 Wh/kg, while Chery disclosed development of a 60 Ah solid-state battery targeting 400 Wh/kg with vehicle integration testing planned for 2027.
CATL has also announced sulfide-based solid-state battery patent filings and pilot production goals around 2027.
Meanwhile, GAC Group previously stated that automotive-grade solid-state battery cells exceeding 60 Ah had entered small-batch production for validation testing.
