Electrode Sheet Coating Layout for Conductivity-Strength Balance
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Solution Overview
Problem
Existing electrode sheets face a trade-off between conductivity and tensile strength due to the incorporation of conduction aids into the binder, which reduces the amount of conduction aids extending between active material particles, and using less binder to improve tensile strength further compromises conductivity.
Innovation Solution
A manufacturing method involving separate coating of active material particles with binder and conduction aid, followed by mixing these coated particles to form an electrode sheet, ensuring a large amount of conduction aid forms conductive pathways without reducing the binder amount, thereby enhancing both conductivity and tensile strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If binder amount is reduced to improve tensile strength, then tensile strength is improved, but conductivity deteriorates
Solution Approach 1:
Conductive pathways are established in advance by coating conduction aid onto active material particles before binder addition. This preliminary establishment of conductive networks allows for reduced binder content without compromising conductivity, as the conductive structure is already in place independent of binder quantity.
2Strength
If fibrillatable binder is used to improve tensile strength, then tensile strength is improved, but conduction aid is more likely to be entangled in binder
Solution Approach 1:
The conduction aid is coated onto active material particles before the fibrillation process occurs. This timing ensures that when the fibrillatable binder undergoes fibrillation and entangles, the conduction aid is already secured on particle surfaces and cannot be trapped within the binder fibrils, maintaining its availability for conductive pathways.
Solution Approach 2:
By pre-coating the conduction aid onto particles, the invention creates a protective barrier that prevents the subsequent harmful action of binder entanglement during fibrillation. The conduction aid is shielded from being incorporated into the binder matrix by this preliminary protective coating step.
Data Source
AI summary
A method for manufacturing an electrode sheet is disclosed. The method may include producing first coated active material particles by mixing first active material particles with at least a binder, producing second coated active material particles by mixing second active material particles with at least a conduction aid; producing an electrode mixture by mixing the first coated active material particles with the second coated active material particles; and forming the electrode mixture into a sheet shape.