The rapid evolution of battery technology has brought the world closer to realizing the potential of solid-state batteries (SSBs). While these batteries promise significant advancements, particularly in safety and energy density, they are still navigating a series of technical challenges. Currently, the solid-state battery market is in its infancy, with China selecting a more gradual path toward commercialization through hybrid (solid-liquid) battery technology, as opposed to the more radical full solid-state technology approach that holds disruptive potential.

At its core, solid-state lithium batteries utilize solid electrolytes instead of liquid ones. This fundamental shift brings with it significant advantages, such as enhanced safety features and increased energy density, positioning solid-state technology as a key trend in battery development. The classification of solid-state batteries bifurcates into hybrid and full solid-state categories based on electrolyte type, with the latter proving more complex and challenging due to materials and interface issues.

Countries like Japan and South Korea, alongside various nations in Europe and North America, pioneered the research and development of solid-state batteries, focusing primarily on fully solid-state designs. However, driven by market demands and practical application considerations, China has opted to progress using hybrid batteries as a transitional approach, marking a pragmatic step in the journey towards a more stable and scalable battery solution.

Hybrid batteries maintain a small amount of liquid electrolyte, which serves to significantly resolve interface contact issues inherent in solid-solid configurations. This hybrid design not only enhances safety but also improves energy density, creating pathways for earlier commercialization. The China Automotive Power Battery Industry Innovation Alliance reported an installation volume of 2,154.7 MWh for hybrid systems in the first half of 2024, showcasing the market's active embrace of this technology.

The evolutionary pathway within the solid-state battery landscape focuses on gradually transitioning towards full solid-state production via in-situ solidification technology. The manufacturing process for these advanced batteries comprises several phases, including the production of electrode sheets and solid electrolyte membranes, as well as the assembly and formation of the battery cells themselves. Each stage must adapt to the specific materials and structural requirements that come with solid-state designs.

Manufacturing processes can be categorized into two main techniques: wet and dry methods. Currently, the wet method is more feasible for mass production. However, the dry method—with its advantages of low energy consumption, reduced costs, and high energy density—is expected to gain traction and stages of adoption over time.

Looking at the more advanced processes, battery cells made from oxide and sulfide solid-state materials often require pressurization to enhance solid-solid contact. Consequently, soft-pack stacking is anticipated to become the dominant technique. This will consequently give rise to new innovations in cell assembly methods, such as integrated stacking, isostatic pressing, and bipolar architecture, while necessitating even higher pressure during the formation stage.

As the manufacturing processes evolve, the equipment needed to support them must also change. Analyzing the three phases of equipment—initial, intermediate, and final—suggests a significant transformation in their requirements. For instance, dry processing equipment including dry mixing apparatus, fiberization machinery, granulation units, and film fabrication technology is expected to gradually take over from wet processing equipment. Additionally, the introduction of thermal composite devices for the electrolyte is foreseen to complement this shift.

The increased complexity associated with solid-state manufacturing methods also means that various processes performed by rolling equipment, such as film formation and thermal composites, will require more advanced technology and capabilities. This anticipated equipment evolution could lead to a dual increase in both value and volume.

In the latter stages of production, changes include the phasing out of liquid injection systems and the rise of stacking systems taking precedence over traditional winding machines. Isostatic press systems and high-pressure formation devices will be crucial components of this new infrastructure. However, the extended duration needed for pressurization may complicate continuous production efforts, presenting obstacles to large-scale manufacturing. Analyses suggest substantial investment requirements, with estimated capital expenditures of approximately 120 million, 150 million, and 250 million yuan respectively for liquid, semi-solid, and solid-state battery setups.

Looking to the future, the market for solid-state batteries is expected to expand exponentially. By 2030, the investment in facilities dedicated to solid-state battery production in China could approach 20 billion yuan, focusing heavily on sectors such as high-end power batteries, consumer batteries, and electric Vertical Take-Off and Landing vehicles (eVTOLs). Analytical models forecast that global demand will soar, reaching shipments as high as 556 GWh by the same year. As indicated by the China Chamber of Commerce for Import and Export of Machinery and Electronic Products, 2030 could witness approximately 251 GWh of solid-state battery shipments in China alone—mostly categorized as hybrid rather than fully solid-state configurations.

With ongoing advancements in materials technology, specifically polymers and sulfides, as well as electrochemistry, equipment demand for solid-state technologies is set to thrive. According to the "Solid-State Lithium Battery Technology Development White Paper," the anticipated capacity for domestic solid-state battery production is already reaching hundreds of GWh, which will inevitably drive up investments in dedicated manufacturing equipment. By 2030, projections indicate that investments for solid-state battery manufacturing equipment could reach around 17.81 billion yuan, clearly demonstrating the high value and growth potential embedded within this innovative technology.