Non-Aqueous Battery Functional Layer Composition for Adhesion Balance
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Solution Overview
Problem
Non-aqueous secondary batteries face challenges in achieving favorable adhesiveness between electrode and separator layers during manufacturing, leading to potential blocking issues and reduced productivity, while also requiring improved cycle characteristics.
Innovation Solution
A non-aqueous secondary battery functional layer composition comprising a block copolymer with an aromatic vinyl monomer unit and an aliphatic conjugated diene monomer unit, having a diblock content within a specific range, along with inorganic particles and a solvent, to enhance pressure-sensitive adhesiveness and blocking resistance, thereby improving cycle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a porous film is used as a functional layer to improve electrolyte solution retainability, then output characteristics improve, but adhesiveness between battery members deteriorates
Solution Approach 1:
The patent uses a composite porous film made by combining polyolefin fine particles (for electrolyte retention and output characteristics) with a polyvinylidene fluoride-hexafluoropropylene copolymer (for adhesiveness and blocking resistance). This composite structure allows both output characteristics and adhesiveness to be improved simultaneously, resolving the technical contradiction between these two properties.
2Reliability
If pressure-sensitive adhesiveness is increased to improve adhesiveness between electrode and separator, then adhesiveness improves, but blocking resistance during winding deteriorates
Solution Approach 1:
The patent carefully controls the adhesion promoter content within 1-10 parts by mass per 100 parts of polyvinylidene fluoride-hexafluoropropylene copolymer, and the porous film thickness within 1-10 μm. These parameter optimizations ensure sufficient adhesiveness between battery members while maintaining low enough surface adhesion to prevent blocking during the winding process, thus resolving this technical contradiction.
3Power
If conventional porous films are used to improve output characteristics, then power performance improves, but cycle characteristics deteriorate
Solution Approach 1:
The patent creates a composite porous film combining polyolefin fine particles (providing electrolyte retention for output characteristics) with a polyvinylidene fluoride-hexafluoropropylene copolymer matrix (providing mechanical stability and blocking resistance for cycle characteristics). This composite approach enables both output characteristics and cycle characteristics to be improved simultaneously, resolving the contradiction between these two performance aspects.
Data Source
AI summary
Provided is a composition for a non-aqueous secondary battery functional layer, capable of forming a non-aqueous secondary battery functional layer that is excellent in pressure-sensitive adhesiveness as well as blocking resistance and allows the secondary battery to exhibit excellent cycle characteristics. The disclosed composition for a non-aqueous secondary battery functional layer includes a polymer and a solvent, the polymer being a block copolymer containing an aromatic vinyl monomer unit and an aliphatic conjugated diene monomer unit, in which the polymer has a diblock content of 5 mass% or more and 85 mass% or less.