Battery Electrode Undercoat Structure for Low Interfacial Resistance
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Solution Overview
Problem
Existing electrode plates for non-aqueous electrolyte secondary batteries do not sufficiently reduce interfacial resistance when swollen with a non-aqueous solvent, affecting output and durability performance.
Innovation Solution
The electrode plate design includes an undercoat layer with a conductive auxiliary agent having an average diameter of 12 nm or smaller, a binder molecular weight of 900,000 or higher, and a thickness of 0.20 μm or smaller, along with an electrode mixture layer having a binder molecular weight of 900,000 or higher, to reduce interfacial resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional undercoat layer with larger conductive auxiliary agents is used, then the manufacturing process is simpler, but the interfacial resistance in the swollen state is not sufficiently reduced
Solution Approach 1:
The patent applies parameter changes by specifying that the average diameter of the conductive auxiliary agent must be 12 nm or smaller, and the thickness of the undercoat layer must be 0.20 μm or smaller. These precise parameter specifications transform the conventional undercoat layer into a highly effective low-resistance interface structure that maintains performance in the swollen state.
Solution Approach 2:
The patent uses composite materials by combining specific conductive auxiliary agents (with average diameter ≤12 nm) with binders (molecular weight ≥900,000) in the undercoat layer. This composite structure achieves both low interfacial resistance and structural integrity, resolving the contradiction between performance and complexity.
2Reliability
If the undercoat layer thickness is increased, then the conductive auxiliary agent coverage is improved, but the interfacial resistance in the swollen state increases
Solution Approach 1:
The patent applies parameter changes by establishing that the undercoat layer thickness must be 0.20 μm or smaller. This counterintuitive parameter specification (thinner is better) resolves the contradiction by creating a highly conductive thin interface layer that maintains low resistance even when the battery is in the swollen state, whereas thicker layers would increase interfacial resistance.
3Reliability
If smaller conductive auxiliary agents are used, then the interfacial resistance is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by specifying the average diameter of the conductive auxiliary agent must be 12 nm or smaller. This precise parameter control enables low interfacial resistance while the patent implicitly addresses manufacturing precision by focusing on the average diameter specification rather than requiring extreme precision for each individual particle.
Data Source
AI summary
This electrode plate for a non-aqueous electrolyte secondary battery comprises: an electrode core with an undercoat layer formed on the surface thereof; and an electrode composite layer formed on the undercoat layer of the electrode core. The undercoat layer can be obtained by applying an undercoat dispersion liquid on the surface of the electrode core and drying the dispersion liquid. The average diameter of an electroconductive auxiliary agent used for the undercoat layer is no greater than 12 nm. The molecular weight of a binder used for the undercoat layer is no less than 900,000. The thickness of the undercoat layer is no greater than 20 μm. The molecular weight of a binder used for the electrode composite layer is no less than 900,000.