Flexible Closure SiO2 Reduction for Energy Storage Sealing
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Solution Overview
Problem
Energy storage devices face a wetting phenomenon due to structural deformation of flexible closures caused by SiO2 reduction at negative potentials, leading to leakage and reduced lifespan.
Innovation Solution
Reducing the weight percentage of SiO2 in flexible closures to 15 wt % or less, combined with minimizing ZnO content and increasing the proportion of materials like polymer, carbon, Al2O3, and resin, to minimize structural deformation and enhance sealing, thereby extending the device's lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SiO2 content in flexible closure is high, then sealing performance is improved, but structural deformation occurs at negative potentials causing wetting and reduced lifespan
Solution Approach 1:
The patent changes the chemical composition parameters of the flexible closure by reducing SiO2 content from conventional high levels to 15 wt% or less, and further reducing ZnO to 1 wt% or less. This parameter modification eliminates the harmful reduction reaction of SiO2 at negative potentials while maintaining sealing performance through alternative material formulations including polymers, carbon, Al2O3, and resin.
Solution Approach 2:
The patent employs a composite material formulation for the flexible closure consisting of multiple components: polymer (35-70 wt%), carbon (13.5-40 wt%), Al2O3 (17-30 wt%), and resin (4.5-15 wt%). This composite approach replaces the problematic SiO2-based formulation with a multi-material system that provides both sealing performance and electrochemical stability at negative potentials.
2Duration of action of stationary object
If SiO2 content is reduced to extend device lifespan, then wetting time is prolonged, but sealing performance may deteriorate
Solution Approach 1:
The patent modifies the composition parameters by reducing SiO2 to 15 wt% or less while simultaneously adjusting other material parameters - increasing polymer content to 35-70 wt% and carbon to 13.5-40 wt%. This coordinated parameter change maintains sealing performance while achieving the goal of extended device lifespan through reduced wetting.
Solution Approach 2:
The patent uses a composite material system where Al2O3 (17-30 wt%) and resin (4.5-15 wt%) work together with the reduced SiO2 content to maintain sealing performance. This composite formulation compensates for the reduced SiO2 while preventing structural deformation and wetting, thereby extending device lifespan without sacrificing sealing reliability.
Data Source
AI summary
This application relates to an energy storage device. In one embodiment, the energy storage device includes an electrode unit including first and second current collectors that are separated by a separator, first and second terminals respectively connected to the first and second current collectors and a case accommodating the electrode unit. The energy storage device also includes a flexible closure covering the case and having first and second through-holes passing therethrough and exposing the first and second terminals to the environment, wherein the flexible closure contains about 15 wt % or less of SiO2. According to some embodiments, since the weight percentage of SiO2 is significantly reduced and thus, the amount and degree of the SiO2 reduction significantly decreases, a structural deformation of the flexible closure at a microscopic level is minimized. Accordingly, a wetting phenomenon is significantly reduced, and thus the life span of an energy storage device significantly increases.