Calendered Semi-Dry Cathode Electrode With Dual-Binder Adhesion
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Solution Overview
Problem
The manufacturing process of cathode electrodes in battery cells is costly due to the use of intaglio printing and recovery systems, and the adhesion force of the cathode active material layer to the current collector is not optimal without conductive glue.
Innovation Solution
A dual-binder system comprising a fibrillating binder (e.g., PTFE) and a co-polymer (PAN-PAA) is used to create a free-standing cathode active material layer, which is directly calendared onto a current collector without intaglio printing or conductive glue, utilizing a warm/hot calendaring process to achieve robust adhesive force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If intaglio printing and conductive glue are used to attach the cathode active material layer to the current collector, then the adhesion force is improved, but the manufacturing cost increases
Solution Approach 1:
The patent removes the conductive glue layer from the electrode structure, extracting the unnecessary intermediate layer that increases manufacturing complexity and cost. The active material layer is directly attached to the current collector through calendaring, eliminating the need for separate gluing operations while maintaining adequate adhesion force.
Solution Approach 2:
The calendaring process serves multiple functions simultaneously: it attaches the active material layer to the current collector, consolidates the electrode structure, and provides sufficient adhesion without requiring separate bonding operations. This multi-functional approach reduces manufacturing steps and costs while achieving the required mechanical strength.
2Manufacturing precision
If intaglio printing is used to create the cathode active material layer, then the manufacturing precision is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent eliminates the intaglio printing process and associated recovery systems, extracting the complex patterning step from the manufacturing workflow. The active material layer is applied directly to the current collector through simpler calendaring operations, reducing device complexity while maintaining functional performance.
Solution Approach 2:
The patent changes the manufacturing parameters from high-precision intaglio printing to calendaring with controlled pressure and temperature. By adjusting these parameters, the process achieves sufficient pattern definition and material attachment without requiring the complex intaglio printing equipment and recovery systems.
3Strength
If conductive glue is used to attach the cathode active material layer, then the adhesion force is improved, but the manufacturing time and process complexity increase
Solution Approach 1:
The patent merges the attachment function into the calendaring process itself, combining material consolidation and adhesion in a single operation. This eliminates the separate gluing step and associated drying/curing time, reducing total manufacturing time while achieving the required adhesion force through direct mechanical and thermal bonding.
Solution Approach 2:
The calendaring process performs multiple functions in one step: it consolidates the active material layer, attaches it to the current collector, and provides sufficient adhesion without requiring separate bonding operations. This multi-functional approach reduces both manufacturing time and process complexity while maintaining adequate mechanical strength.
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 reduces manufacturing costs and enhances the adhesion force of the cathode active material layer to the current collector, achieving comparable or higher peeling forces than traditional methods while eliminating the need for intaglio printing and conductive glue.
Implementation Method 1
a binder including a fibrillating binder and a co-polymer including polyacrylonitrile (PAN) and polyacrylic acid (PAA)
Implementation Method 2
utilizing a warm/hot calendaring process to achieve robust adhesive force
Implementation Method 3
hydrogen in a carboxyl (COOH) of the PAA is at least partially substituted by a lithium ion via reaction with a lithium-based chemical to form PAA LixH1-x
Data Source
AI summary
A battery cell includes A anode electrodes, C cathode electrodes, and S separators where C, A and S are integers greater than one. The C cathode electrodes each include a cathode current collector and a cathode active material layer arranged on the cathode current collector. The cathode active material layer comprises a cathode active material, a conductive filler, and a binder including a fibrillating binder and a co-polymer including polyacrylonitrile (PAN) and polyacrylic acid (PAA).