Polyolefin Separator with PVDF Porous Layer for Battery Adhesion
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Solution Overview
Problem
Conventional nonaqueous electrolyte secondary batteries face challenges in maintaining charge capacity after repeated charge and discharge cycles due to issues with electrolyte retention and ion permeability.
Innovation Solution
Incorporating a polyolefin porous film with a porous layer containing a polyvinylidene fluoride-based resin, specifically with a high percentage of α-form polyvinylidene fluoride, between the separator and electrodes, along with a positive electrode plate that maintains its active material layer integrity during bending and a negative electrode plate with enhanced adhesion, to control electrolyte retention and fluid movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a polyolefin porous film is used as a separator, then electrolyte retention is improved, but ion permeability deteriorates
Solution Approach 1:
The patent employs a polyolefin porous film with specifically controlled pore structure to achieve both electrolyte retention and ion permeability. The porous structure allows ion transport while the pore size distribution and film morphology are optimized to retain electrolyte effectively.
Solution Approach 2:
The patent uses a composite structure combining polyolefin porous film with additional functional layers or modifications to simultaneously achieve electrolyte retention and maintain ion permeability. The composite approach allows optimization of both properties through synergistic material combinations.
2Quantity of substance
If the separator structure is optimized for electrolyte retention, then charge capacity is improved, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes charge capacity by adjusting parameters of the polyolefin porous film such as pore size, porosity, and film thickness. These parameter changes enable effective electrolyte retention without requiring overly complex structural designs, maintaining manufacturability while improving 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
This configuration enhances the charge capacity and cycle stability of the battery by maintaining adhesiveness and controlling electrolyte retention and fluid movement, leading to improved ion permeability and reduced internal resistance.
Implementation Method 1
a nonaqueous electrolyte secondary battery separator including a polyolefin porous film
Implementation Method 2
a porous layer containing a polyvinylidene fluoride-based resin
Implementation Method 3
controls an electrolyte retention property of the separator itself
Data Source
AI summary
A nonaqueous electrolyte secondary battery including: a separator including a polyolefin porous film; a porous layer containing a polyvinylidene fluoride-based resin; a positive electrode plate whose active material layer is not peeled from the positive electrode plate until the positive electrode plate is bent 130 or more times; and a negative electrode plate whose active material layer is not peeled from the negative electrode plate until the negative electrode plate is bent 1650 or more times, wherein: diethyl carbonate dropped on the polyolefin porous film diminishes at a rate of 15 sec/mg to 21 sec/mg; the diethyl carbonate has a spot diameter of not less than 20 mm 10 seconds after the diethyl carbonate was dropped on the polyolefin porous film; and the polyvinylidene fluoride-based resin contains an α-form polyvinylidene fluoride-based resin in an amount of not less than 35.0 mol %.