BYD Files Patent for Composite Sulfide Solid Electrolyte Membrane, China Targets 2027 Pilot Production

Car News China China

Overview

Chinese EV giant BYD has filed a new patent (CN121983643A) for a composite solid electrolyte membrane designed for all-solid-state batteries. This innovation combines inorganic solid electrolyte particles with a polymer electrolyte fiber network, aiming to enhance both ion conductivity and mechanical strength. Multiple Chinese battery manufacturers, including CALB which has already unveiled a 60 Ah, >450 Wh/kg prototype, are targeting pilot production around 2027, signaling rapid advancements in the region.

In Depth

Accelerating Solid-State Battery Development in China

BYD, a leading Chinese electric vehicle (EV) manufacturer, is intensifying its focus on the development of all-solid-state battery (ASSB) technology, a critical next-generation power solution. As part of this effort, the company has filed a new patent (CN121983643A) for a composite solid electrolyte membrane. This move underscores the industry’s drive to achieve higher energy densities and significantly improved safety features, surpassing the inherent limitations of current liquid-electrolyte lithium-ion batteries. ASSBs are particularly attractive due to their elimination of flammable liquid electrolytes, thus drastically reducing fire risks.

Technical Characteristics of BYD’s New Patent

BYD’s patent focuses on a composite solid electrolyte membrane that integrates inorganic solid electrolyte particles within a polymer electrolyte fiber network. The inorganic component is designed to provide high ionic conductivity, which is essential for efficient charge and discharge. Simultaneously, the polymer fiber network offers crucial mechanical flexibility and structural integrity to the membrane. This hybrid approach aims to address common challenges in solid-state interfaces, such as high contact resistance, while concurrently boosting the overall ionic conductivity of the electrolyte and serving as a mechanical barrier against lithium dendrite formation. Such improvements are expected to lead to enhanced battery performance and extended cycle life.

Outlook for China’s Battery Industry and Commercialization Targets

The Chinese government has designated ASSB technology as a strategic priority, and BYD’s patent filing reflects the robust momentum in this sector. Numerous domestic battery manufacturers are engaged in a competitive race, with many targeting pilot production around 2027. For instance, CALB has already showcased a large-capacity 60 Ah solid-state battery prototype boasting an energy density exceeding 450 Wh/kg, demonstrating the advanced technical capabilities of Chinese firms in this domain. These concerted efforts suggest that ASSBs could see significant commercial deployment in the EV market within the next few years, potentially bringing about a transformative shift in global EV and energy storage landscapes.