Integrated Electrode Assembly with Three-Phase Separator
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Solution Overview
Problem
Lithium secondary batteries face challenges in improving energy density, safety, and reducing process time, particularly due to issues with separator contraction leading to short-circuiting and limited ionic conductivity, which affects their performance and safety.
Innovation Solution
An integrated electrode assembly with a three-phase separation layer comprising a liquid-phase component, a solid-phase component, and a polymer matrix, where linear polymers and cross-linked polymers form a viscoelastic structure, preventing separator contraction and enhancing ionic conductivity by allowing the liquid-phase component to flow into the electrodes during assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional stretched separator is used to electrically separate the cathode and anode, then electrical separation is achieved, but the separator contracts at high temperature causing short-circuiting and safety problems
Solution Approach 1:
The patent employs a composite separation layer comprising three phases: solid-phase particles (inorganic or organic) dispersed in a polymer matrix, with liquid-phase electrolyte filling the spaces between. This composite structure combines the electrical separation function with high-temperature stability, as the solid-phase component prevents contraction while the polymer matrix maintains flexibility and ionic conductivity.
Solution Approach 2:
The patent changes the physical state parameters of the separation layer by incorporating a liquid-phase component (electrolyte) alongside solid-phase particles and polymer matrix. This multi-phase approach allows the separation layer to maintain its dimensional stability at high temperatures while preserving ionic conductivity through the liquid electrolyte, preventing the contraction-induced short-circuiting problem.
2Reliability
If an unstretched solid electrolyte is used to electrically separate the cathode and anode, then electrical separation is achieved, but ionic conductivity is limited resulting in poor battery performance
Solution Approach 1:
The patent creates a composite separation layer that integrates solid-phase particles, polymer matrix, and liquid-phase electrolyte. The liquid-phase component provides high ionic conductivity comparable to conventional liquid electrolytes, while the solid-phase particles embedded in the polymer matrix maintain structural integrity and electrical separation, achieving both high ionic conductivity and reliable electrical separation.
Solution Approach 2:
The patent applies local quality by having the liquid-phase electrolyte specifically distributed in the spaces between solid-phase particles within the polymer matrix. This localized arrangement ensures that ionic conductivity is enhanced in the regions where liquid electrolyte is present, while the solid-phase regions provide structural support and electrical separation, optimizing both functions simultaneously.
3Quantity of substance
If large-area electrodes are used to increase capacity, then energy density is improved, but wetting uniformity deteriorates leading to poor performance
Solution Approach 1:
The patent's composite separation layer with liquid-phase electrolyte, solid-phase particles, and polymer matrix creates a structure that naturally wets the electrode surfaces uniformly. The liquid electrolyte component ensures complete coverage and penetration into the electrode pores, while the solid-phase particles and polymer matrix provide a stable framework that maintains uniform distribution across large-area electrodes, achieving both high capacity and uniform wetting.
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 solution prevents short-circuiting and thermal runaway, improves high-temperature safety, increases ionic conductivity, and enhances durability and cycle properties of the electrodes, addressing the limitations of existing battery structures.
Implementation Method 1
the liquid-phase component of the separation layer flows into the electrodes (i.e., the cathode and the anode) during preparation of the integrated electrode assembly to greatly improve wetting properties of the electrodes and to increase ionic conductivity of the electrodes
Implementation Method 2
a polymer matrix in which linear polymers and cross-linked polymers form a viscoelastic structure with the liquid-phase component and the solid-phase component being incorporated in the polymer matrix
Data Source
Figure 1~2
Figure 3~4
AI summary
Disclosed herein is an integrated electrode assembly including a cathode, an anode, and a separation layer disposed between the cathode and the anode. The cathode, the anode, and the separation layer are integrated with each other. The separation layer includes 3 phases including a liquid-phase component containing an ionic salt, a solid-phase component supporting the separation layer between the cathode and the anode, and a polymer matrix in which linear polymers and cross-linked polymers form a viscoelastic structure with the liquid-phase component and the solid-phase component being incorporated in the polymer matrix. The polymer matrix is coupled to each of the cathode and the anode. The liquid-phase component of the separation layer flows into the electrodes (i.e., the cathode and anode) during preparation of the integrated electrode assembly to greatly improve wetting properties of the electrodes and to increase ionic conductivity of the electrodes.