Battery Separator Substrate for Lamination Pressure and Breakdown Voltage
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Solution Overview
Problem
Existing battery separators face issues with deformation and reduced breakdown voltage due to high-pressure lamination, leading to Hi-pot failure and low voltage failure, particularly when using pressure-vulnerable substrates.
Innovation Solution
A separator substrate with a polymer material comprising polyolefin-containing resin, featuring fibrils with specific diameters and porosity, and a thickness range of 5 µm to 50 µm, ensuring a pressure difference of 100 psi or less, and optionally including a heat-resistant layer with inorganic particles and binder resin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high pressure is applied during lamination to improve adhesion, then adhesive strength increases, but separator deformation and pore damage occur
Solution Approach 1:
The patent changes the physical-chemical parameters of the separator substrate by controlling porosity (30-80%), thickness (5-50 µm), and mechanical strength (≥100 MPa) to optimize performance under lamination pressure, allowing the separator to maintain shape while achieving adequate adhesion
Solution Approach 2:
The patent uses composite material structures including polyolefin-based porous substrates combined with heat-resistant layers containing inorganic particles (alumina, silica) and binder resins, creating a multi-layer composite that provides both adhesion and dimensional stability during lamination
2Strength
If high pressure is applied during lamination to improve adhesion, then adhesive strength increases, but breakdown voltage decreases
Solution Approach 1:
The patent optimizes substrate parameters including porosity (30-80%), thickness (5-50 µm), and mechanical strength (≥100 MPa) to maintain dielectric integrity under pressure while achieving adequate adhesion, preventing Hi-pot failure
Solution Approach 2:
The patent employs composite structures with polyolefin porous substrates and heat-resistant layers containing inorganic particles (alumina, silica) that maintain electrical insulation properties under lamination pressure, preserving breakdown voltage characteristics
3Shape
If thin substrate is used to reduce thickness change, then shape stability improves, but mechanical strength decreases
Solution Approach 1:
The patent changes material parameters by using polyolefin resins with specific molecular weight distributions (PDI 1.05-2.0) and controlling substrate thickness (5-50 µm) with porosity (30-80%) to achieve both thin profile and adequate mechanical strength
Solution Approach 2:
The patent creates composite structures where thin porous polyolefin substrates are combined with heat-resistant layers containing inorganic particles and binder resins, providing mechanical reinforcement while maintaining thin overall thickness
Data Source
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AI summary
A separator substrate for an electrochemical device. The separator substrate has pores that are small and uniform in size, good physical strength and durability, and high dielectric breakdown voltage. Therefore, with the use of the separator substrate, the probability of short circuiting is low.