Microvast Holdings has made progress in developing its True All-Solid-State Battery (ASSB) technology. This advancement improves safety, energy density, and efficiency for applications, including electric school buses. It also offers potential for future use in electric vehicles (EVs).
Figure 1. The cross-sectional analysis visualization of Microvast’s bipolar stacked ASSB. (Graphic: Business Wire)
Unlike conventional lithium-ion (Li-ion) or semi-solid-state batteries, Microvast’s ASSB uses a bipolar stacking architecture that enables internal series connections within a single battery cell.
Traditional Li-ion and semi-solid state batteries, constrained by the limitations of liquid electrolytes, typically operate at nominal voltages of 3.2 to 3.7 V per cell. The technology eliminates liquid electrolytes, allowing a single cell to achieve dozens of volts or higher. This is unattainable by any battery containing liquid electrolytes, which would otherwise decompose under such high voltages.
Figure 1A (left) and Figure 1B (right) provide a detailed cross-sectional analysis of Microvast’s bipolar stacked five-layer solid-state battery cell. Figure 1A illustrates the morphological structure, highlighting distinct layers of the cathode, anode, and solid electrolyte.
This precise layer alignment ensures optimized current distribution and mechanical stability. Figure 1B displays the elemental mapping (EDS analysis) of the same cross-section, displaying the uniform distribution of key materials (Ni, Co, Mn, Si, S) across the cathode, anode, and solid electrolyte interfaces. This consistency is critical for preventing localized failures and maintaining stable long-term performance under heavy operational loads.
Figure 2. The voltage-capacity curve of Microvast’s ASSB for charge and discharge cycles. (Graphic: Business Wire)
The bipolar design reduces the number of interconnections between cells, modules, and packs, simplifying the overall system architecture and enhancing energy efficiency and operational safety. Microvast has developed its all-solid electrolyte separator membrane based on an advanced polyaramid separator, which is non-porous and tailored specifically for solid-state applications.
The separator ensures ionic conductivity, structural stability, and long-term durability, addressing one of the most critical technical challenges in solid-state battery technology. It supports stable high-voltage operation without compromising safety or long-term reliability.
Figure 2 represents the voltage-capacity curve of Microvast’s ASSB during charge and discharge cycles. The graph reveals a stable operational voltage range between 12 and 21 V, a clear indicator of the battery’s advanced engineering and true solid-state nature.
Any presence of liquid electrolyte would prevent stable operation in this high-voltage range, further reinforcing the uniqueness of this technology.
Microvast’s ASSB technology offers a new approach to customized cell design. Its flexible form and voltage configuration allow solid-state batteries to be tailored to meet the energy and space needs of advanced robotic systems, supporting the development of AI-driven applications
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