Non-Newtonian Rheology Fundamentals in Battery Pack Thermal Gap Fillers
Non-Newtonian gap filler rheology controls high-shear dispensing speeds, wet squeeze forces, and long-term settlement stability in battery pack assembly.
Particle Jamming
Meaning
A particulate flow transition occurs when the concentration of suspended particles in a fluid exceeds a critical threshold, causing the viscosity to diverge and the mixture to behave like a solid. Electrode slurry mixing systems monitor for particle jamming to prevent catastrophic pipe blockages and mechanical failures in pump assemblies. This phenomenon depends on the solid volume fraction and the shape distribution of the active material grains, making it a critical design parameter for slurry transport lines.
Processing Failure
When shear stress increases during high-speed pumping, the sudden transition to a jammed state can rupture filter screens or stall mixing blades. The occurrence of particle jamming forces immediate line shutdowns and requires intensive manual cleaning of delivery manifolds. Slurry formulations must be designed with sufficient polymer dispersants to prevent these localized lockups from developing.
Viscosity Profile
As the slurry approaches the critical density, the individual particles form transient contact networks that resist deformation. This phase transition alters the fluid dynamics from a manageable shear-thinning fluid to a highly unpredictable dilatant paste. Rheological testing must map these stress limits to guarantee that processing shears never trigger the transition.
Control Measure
Optimization of the particle size distribution through bimodal blending represents the primary method to delay the onset of this locking mechanism. By filling the gaps between large particles with smaller spheres, the mixture flows more freely at higher solid loadings. Sourcing teams use these particle design parameters to select slurry raw materials that optimize throughput without risking pump damage.