Electrode Binder Composition for Thick Battery Flexibility
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Solution Overview
Problem
Increasing the thickness of electrodes in secondary batteries leads to reduced flexibility, cracking during winding, and deterioration of battery characteristics such as IV characteristics, cycle characteristics, and rate characteristics, while increasing the amount of binder for flexibility worsens these issues.
Innovation Solution
A binder composition for non-aqueous secondary battery electrodes is developed, comprising a polymer that achieves a specific relationship between breaking stress and breaking strain, enhancing electrode flexibility and battery characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of electrode is increased to improve energy density, then energy density is improved, but flexibility is reduced and cracking occurs during winding
Solution Approach 1:
The invention changes the mechanical parameters of the binder by specifying a breaking stress of 0.01 to 5 MPa and breaking strain of 0.05 to 0.5, which optimizes the electrode's flexibility and prevents cracking during winding while maintaining high energy density
Solution Approach 2:
The invention uses a composite binder composition comprising multiple polymers (polymer 1 with nitrile groups, polymer 2 with carboxyl groups, and optionally polymer 3 with hydroxyl groups) that work together to provide both flexibility and structural integrity for thick electrodes
2Strength
If the amount of binder is increased to improve flexibility, then flexibility is improved, but battery characteristics deteriorate
Solution Approach 1:
The invention optimizes the binder content to 1-10 parts by mass per 100 parts by mass of active material, and specifies precise breaking stress (0.01-5 MPa) and breaking strain (0.05-0.5) parameters to achieve the right balance between flexibility and battery performance
Solution Approach 2:
The invention uses different polymers with specific functional groups (nitrile, carboxyl, hydroxyl) that provide localized binding effects, ensuring adequate adhesion without excessive binder content that would harm battery characteristics
Data Source
AI summary
Provided is a binder composition for a non-aqueous secondary battery electrode that can suitably be used to produce an electrode having excellent flexibility and that can enhance battery characteristics of a secondary battery including the obtained electrode. The binder composition for a non-aqueous secondary battery electrode contains a polymer A and yields a film X having a breaking stress [MPa] and a breaking strain [-] according to tensile testing that satisfy the following relationship formula: 0.010 ≤ breaking stress [MPa]/breaking strain [-] ≤ 1.000.