20L Vacuum Planetary Mixer for Lithium Battery Slurry and High-Viscosity Materials

The 20L Vacuum Planetary Mixer is a compact yet powerful mixing solution engineered for processing high-viscosity materials across multiple industries. This tabletop unit combines planetary motion, high-speed dispersion, and vacuum deaeration in a single system, making it particularly suitable for lithium battery slurry preparation, adhesive manufacturing, cosmetic cream production, and food paste processing. With a working volume of 20 liters and the ability to handle viscosities up to 10,000,000 cps, this mixer delivers the performance of larger industrial units in a space-saving, laboratory-friendly footprint.

As a vacuum planetary mixer, this equipment addresses the critical challenges of mixing high-solid-content, high-viscosity formulations. The dual-action mixing system—combining slow-speed kneading with high-speed dispersion—ensures thorough incorporation of powders into liquids while eliminating dead zones through continuous wall scraping. The optional presser (extruder) attachment further enhances productivity by enabling direct discharge of finished high-viscosity products from the mixing container, streamlining the workflow from mixing to packaging. This unit is widely adopted in lithium battery production lines for cathode and anode slurry preparation, where uniformity directly impacts coating quality, adhesion, and electrochemical performance .

Working Principle

The Vacuum Planetary Mixer operates on a compound motion principle that delivers exceptional mixing efficiency. The planetary gear system drives multiple agitators—typically two low-speed mixing blades and one high-speed disperser—to revolve around the central axis of the mixing vessel while simultaneously rotating on their own axes . This dual motion creates complex flow patterns that continuously renew shear zones throughout the material, ensuring every particle is subjected to intensive mixing forces.

During operation, the low-speed mixing blades rotate at 0-98 rpm (self-rotation) while orbiting at 0-42 rpm (revolution), generating powerful kneading and folding actions that circulate materials from the bottom to the top and from the center to the wall . Simultaneously, the high-speed disperser operates at up to 2,980 rpm, applying intense shear forces that break down agglomerates and ensure thorough powder-liquid wetting. A PTFE scraper blade mounted on the planetary frame continuously sweeps the vessel wall, preventing material buildup and eliminating mixing dead zones . This combination makes the mixer particularly effective for processing materials with viscosities ranging from 5,000 to 10,000,000 cps.

The vacuum system, capable of achieving -0.09 to -0.098 MPa, serves multiple critical functions. It removes entrapped air during mixing, eliminating bubbles that could compromise product quality and structural integrity. This degassing capability is especially vital for lithium battery slurries, where air bubbles cause pitting defects in electrode coatings . The vacuum also facilitates material transfer and can be used for powder suction, minimizing dust and contamination. The sealed vessel design supports both vacuum and pressure operations, with the vessel jacket enabling precise temperature control through circulation of heating or cooling media (water, oil, or steam) .

Key Features

High-Viscosity Processing Capability: The mixer handles viscosities up to 10,000,000 cps and solid contents up to 90%, making it suitable for lithium battery slurries, silicone sealants, structural adhesives, ceramic pastes, and high-solid-content food pastes . The powerful gearbox and motor system deliver consistent torque even under heavy loads.

Advanced Mixing Geometry: Clearances between mixing blades (3-8mm), blade-to-wall (2-5mm), and blade-to-bottom (2-4mm) are precision-machined to optimize mixing efficiency . The PTFE scraper maintains continuous wall cleaning, ensuring complete material turnover and consistent batch quality.

Versatile Agitator Configurations: Various mixing head combinations are available, including twist impellers, dispersing discs, homogenizers, and scrapers. These can be tailored to specific applications such as battery slurry, silicone rubber, solder paste, ointments, or food pastes .

Vacuum and Temperature Control: The vacuum system achieves -0.09 MPa or better, with vacuum pump power of 0.55-1.5KW. The jacketed vessel supports electric, steam, or water circulation heating/cooling, with temperature monitoring ensuring process accuracy .

Lifting and Discharge Options: 0.5-30L models feature electric lifting, while 50L and above use hydraulic lifting . The optional presser (extruder) attachment enables direct discharge of high-viscosity materials from the mixing container, eliminating transfer challenges .

Model Classification

The Vacuum Planetary Mixer series is organized into three primary categories to serve different production scales:

Laboratory Series (0.5-40L): Tabletop units ideal for R&D, pilot production, and small-batch manufacturing. Features include electric lifting, vacuum capability, and optional explosion-proof or special coating configurations. Customization options address specific industry requirements, including dental materials, cosmetic creams, and food applications. The presser attachment can be integrated for direct product discharge.

Mid-Scale Series (50-250L): Floor-mounted units designed for small-to-medium production volumes. Standard hydraulic lifting and robust construction support continuous operation. Dedicated PU adhesive versions and 500L heavy-duty rail configurations are available, with explosion-proof options for chemical applications.

Large-Scale Series (300-2000L): Gantry-structured units for high-volume industrial production. The 800L and 850L models are specifically engineered for lithium battery slurry production, with the full range supporting non-standard customization .

Note: Custom sizes from 2L to 2000L available upon request. Capacities of 800L and above are particularly suited for lithium battery electrode slurry production .

Technical Specifications (SXJ-20 Model)

Specifications based on the SXJ-20 model from Maxwell's product line. Units up to 30L use electric lifting; 50L and above employ hydraulic lifting .

Application Industries

New Energy Lithium Battery: The 20L Vacuum Planetary Mixer is extensively used for preparing cathode and anode slurries (LiCoO₂, LiFePO₄, NCM, NCA, silicon-carbon composites, and sodium-ion battery materials). The vacuum operation minimizes air bubbles that cause pitting defects in electrode coatings, while the powerful dispersion system ensures uniform distribution of conductive additives (carbon black, CNT) and binders (PVDF, SBR) .

Electronics and Adhesives: Ideal for electronic solder pastes, potting compounds, thermal interface materials, silicone sealants, PU adhesives, MS polymers, and epoxy resins. The mixer handles the high filler loadings common in these applications while maintaining uniform dispersion and bubble-free products .

Chemical and Industrial: Suitable for silicone rubber, glass glue, sealants, coatings, pigments, dyes, synthetic resins, and ceramic pastes. The wall-scraping design ensures complete material turnover, eliminating residue and batch-to-batch variation .

Cosmetics and Personal Care: Perfect for lipsticks, foundations, creams, ointments, and hot melt adhesives used in cosmetic packaging. The vacuum degassing ensures bubble-free products with smooth textures and extended shelf life .

Food Processing: Applicable to jams, nut butters, sauces, fillings, and other high-viscosity food pastes. Stainless steel construction meets food-grade hygiene requirements, while precise temperature control prevents ingredient degradation.

Dental and Pharmaceutical: Used for dental impression materials, medical ointments, and pharmaceutical creams. Custom designs accommodate specific hygiene and mixing requirements, with material options including SUS316L for medical applications .