China's BYD Files Six New Patents for All-Solid-State Batteries… Is the Technology Gap with South Korea Widening?

*This content was translated by AI.

Chinese automaker and battery manufacturer BYD has publicly disclosed six new patents related to all-solid-state batteries (SSBs), based on a dual-electrolyte technology that combines halide and sulfide-based electrolytes. Following the recent approval of a cathode composite structure patent by China's National Intellectual Property Administration (CNIPA), BYD plans to utilize this newly disclosed technology to begin small-scale pilot production of all-solid-state battery cells based on dual-electrolyte cathode materials in 2027. The company also intends to install these batteries in prototype test vehicles to conduct real-world performance evaluations.

According to BYD, the six newly disclosed patents focus on improving interfacial contact between solid electrolytes and electrodes, as well as maintaining stable contact between solid materials during charging and discharging cycles. Notably, among the material chemistry patents, 'CN122494747A' introduces an intermediate layer with ionic conductivity and electrochemical stability between halide and sulfide electrolytes to prevent unwanted chemical reactions and extend battery lifespan. A review of the technical patent documentation reveals that 'CN122494554A' specifies a design featuring a first solid-electrolyte buffer layer placed between the cathode active material and sulfide electrolyte to prevent thermal runaway, while also limiting heat release from the cathode active material layer to 117 joules per gram (J/g) or less.

Additionally, BYD announced that patent 'CN122494567A', which focuses on improving cathode structure, adopts a dual-layer design combining an inner layer of single-crystal cathode material mixed with solid electrolyte for enhanced crack resistance during charging and discharging, and an outer layer using polycrystalline cathode material for superior output performance, thereby compensating for each other's weaknesses. Another patent, 'CN122494558A', describes a method of mixing lithium-treated metal oxides and metal sulfides with solid electrolytes to reduce interfacial electrical resistance between solids while increasing output power and discharge capacity.

Beyond technical patents, the disclosure also includes two patents related to commercialization processes and quality control. Patent 'CN122494552A' employs a gradient distribution technique that applies more ionic liquid impregnation agent to the outer regions of the electrode active material layer than to its center, preventing ion transport obstacles and enhancing interfacial performance. Meanwhile, 'CN122494553A' establishes a quality metric called 'Re', which defines a contact ratio requiring at least 60% of cathode particles to be in contact with electrolyte particles, enabling systematic management of battery lifespan and capacity.

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*This content was translated by AI.