Homogeneous Electrode Material Mixing via Gravity and Shear
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Solution Overview
Problem
Existing methods for producing electrode active material compositions face challenges in achieving high homogeneity and consistency due to mechanical stress, agglomerate formation, and inefficient processing times, particularly in large-scale production, leading to reduced performance and limited recycling of reject products.
Innovation Solution
A method involving a gravity mixer to create a homogeneous mixture of particulate material and additive, followed by the introduction of shear forces with a binding agent in a jet mill or extruder, with controlled temperature and energy input to prevent fibrillation and agglomerate formation, and subsequent removal of dispersed gases to produce a stable and conductive electrode active material composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If mechanical mills (jet or ball mills) are used to introduce shear forces for fibrillation of binding agent particles, then the binding agent adheres to particle surfaces forming a stable foil, but the process requires additional cooling steps and multiple method steps increasing complexity
Solution Approach 1:
The patent combines the mixing and fibrillation steps into a single continuous process in the extruder. The binding agent particles are fed together with active material and conductive additive into the extruder where shear forces during extrusion simultaneously achieve both mixing and fibrillation, eliminating the need for separate cooling and fibrillation steps required by jet mill methods.
Solution Approach 2:
The patent replaces the jet mill mechanical system (which requires cooling to prevent agglomerate formation) with an extruder system that uses controlled shear forces during extrusion. The extruder maintains simpler thermal conditions while achieving effective fibrillation through mechanical shear during the extrusion process itself.
2Strength
If jet mill is used for fibrillation at temperatures above Tg of binding agent, then good plasticization and adhesion occur, but runup and rundown times increase reducing productivity
Solution Approach 1:
The patent implements a continuous extrusion process where binding agent particles are fed continuously along with other components into the extruder. The fibrillation occurs continuously during extrusion without interruption for cooling or heating cycles, eliminating the runup and rundown times inherent in batch jet mill processes while maintaining effective plasticization through sustained shear forces.
3Stability of the object's composition
If mechanical mills are used for mixing and fibrillation, then binding agent particles are effectively processed, but dispersed gases remain in the composition reducing homogeneity
Solution Approach 1:
The patent incorporates a degassing step after extrusion where dispersed gases are removed from the electrode material composition. This extraction of harmful gases follows the extrusion process, ensuring that the fibrillation and mixing benefits are maintained while eliminating the gas entrapment issue that plagues mechanical mill methods.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables the production of a highly homogeneous and stable electrode active material composition with reduced mechanical stress, shorter processing times, and improved cohesion, resulting in enhanced performance and recyclability, suitable for electrochemical energy storage systems like lithium-ion batteries.
Implementation Method 1
production of a homogenous mixture G1 from the at least one particulate material M and the at least one additive Z in a gravity mixer
Implementation Method 2
production of a mixture G2 from the mixture G1 and the at least one binding agent B, with the introduction of shear forces
Implementation Method 3
the polymer binding agent experiences high shear forces such that a plasticization of the polymer occurs at least locally
Implementation Method 4
removal of dispersed gases from mixture G2
Data Source
AI summary
A method is provided for producing a homogenous particulate material composition, including at least one particulate material M, at least one additive Z, and at least one binding agent B, the method including providing at least one particulate material M, at least one additive Z, and at least one binding agent B; producing a homogenous mixture G1 from the at least one particulate material M and the at least one additive Z in a gravity mixer; producing a mixture G2 from the mixture G1 and the at least one binding agent B, with the introduction of shear forces; and removing dispersed gases from the mixture G2.