Non-Aqueous Battery Separator Layer for Heat Press Adhesion
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Solution Overview
Problem
Existing separators for non-aqueous secondary batteries face challenges in achieving strong adhesion to electrodes during dry heat pressing while maintaining heat resistance and preventing shrinkage at high temperatures.
Innovation Solution
A separator comprising a porous substrate with an adhesive porous layer containing a polyvinylidene fluoride type resin, an acrylic type resin, and metal sulfate particles, where the average primary particle diameter of the metal sulfate particles is between 0.01 μm and less than 0.30 μm, enhancing adhesion and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a porous layer containing inorganic particles is provided on a porous substrate to improve heat resistance, then heat resistance is improved, but adhesion to electrode during dry heat press deteriorates
Solution Approach 1:
The adhesive porous layer is formed as a composite material containing both polyvinylidene fluoride type resin (providing heat resistance) and acrylic type resin (providing adhesion). This composite structure allows simultaneous achievement of heat resistance and adhesion properties that individual materials cannot provide alone.
Solution Approach 2:
The invention specifies precise compositional parameters: acrylic type resin content of 5-50 mass%, and metal sulfate particle diameter of 0.01-0.30 μm. By controlling these parameters, the adhesive porous layer achieves optimal balance between heat resistance and adhesion during dry heat press.
2Strength
If a resin layer containing adhesive resin is provided on a porous substrate to improve adhesion, then adhesion is improved, but heat resistance deteriorates
Solution Approach 1:
The adhesive porous layer combines polyvinylidene fluoride type resin (heat resistant) with acrylic type resin (adhesive), creating a composite that simultaneously provides both heat resistance and adhesion properties, resolving the contradiction between these two requirements.
Solution Approach 2:
The adhesive porous layer is applied locally on the porous substrate where adhesion is needed, while the substrate itself provides the base heat resistance. This localized approach allows different regions to fulfill different functions.
3Ease of manufacture
If metal sulfate particles with larger diameter are used, then manufacturing ease is improved, but adhesion during dry heat press deteriorates
Solution Approach 1:
The invention specifies a precise particle diameter range of 0.01-0.30 μm for metal sulfate particles. This parameter optimization ensures sufficient surface area for adhesion while maintaining manufacturability, resolving the contradiction between manufacturing ease and adhesion performance.
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
The separator exhibits excellent adhesion to electrodes during dry heat pressing and maintains structural integrity at high temperatures, improving production yield and battery performance.
Implementation Method 1
a laminate in which a separator is disposed between a positive electrode and a negative electrode may be subjected to dry heat pressing
Implementation Method 2
a separator which is one of members constituting a non-aqueous secondary battery is required to have heat resistance that a film is not easily broken or shrunk even when the temperature inside the battery is high
Data Source
AI summary
Provided is a separator for a non-aqueous secondary battery containing a porous substrate; and an adhesive porous layer that is provided on one side or on both sides of the porous substrate, and that contains a polyvinylidene fluoride type resin, an acrylic type resin and metal sulfate particles, in which an average primary particle diameter of the metal sulfate particles contained in the adhesive porous layer is from 0.01 μm to less than 0.30 μm.