Secondary Battery With Flowable Active Material Fluid
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Solution Overview
Problem
Lithium secondary batteries face challenges in increasing battery capacity due to electrolyte diffusion limitations, particularly in the thickness direction, and existing configurations face production issues and have not been realized effectively.
Innovation Solution
A novel secondary battery design featuring a first active material fluid electrically connected to a first electrode and a second electrode with a structure containing a second active material, separated by an ion-conducting and insulating membrane, which allows for closer proximity of the active materials and fluid flowability, reducing ion conductivity requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of the electrode is increased to increase battery capacity, then the battery capacity increases, but the flow path of the electrolyte in the thickness direction becomes longer and the concentration gradient of the electrolyte cannot be relieved
Solution Approach 1:
The patent transitions from a conventional planar electrode structure to a three-dimensional stacked structure where multiple thin electrode layers are arranged in the thickness direction. This dimensional change allows the electrolyte to access active materials through short vertical paths while maintaining high capacity through stacking, effectively resolving the contradiction between capacity and flow path length.
Solution Approach 2:
The electrode is divided into multiple thin layers stacked together, with each layer having a thickness that allows efficient electrolyte penetration. By segmenting the thick electrode into multiple thin segments, the patent maintains short electrolyte flow paths in each layer while achieving high overall capacity through the stacked configuration.
2Reliability
If a novel configuration with needle-point holder-shaped electrodes is used, then battery characteristics may be improved, but there are many problems in terms of production and the configuration has not been realized yet
Solution Approach 1:
The patent modifies the electrode geometry from complex needle-point holder shapes to simplified planar or stacked structures with optimized thickness parameters. This parameter change maintains the beneficial short ion transport paths while dramatically improving manufacturability through conventional electrode fabrication techniques.
Solution Approach 2:
Instead of creating complex three-dimensional needle structures that are difficult to manufacture, the patent inverts the approach by using simple planar electrodes stacked in the thickness direction. This inversion achieves the same functional benefit of short ion paths while being much easier to produce using standard battery manufacturing processes.
3Reliability
If the distance of movement of carrier ions is shortened, then battery characteristics improve, but the distance of electron transfer must be maintained for proper electrode function
Solution Approach 1:
The electrode structure is segmented into multiple thin layers, each with short ion transport distances. The conductive framework within each layer ensures electron transfer paths are maintained throughout the electrode structure, resolving the contradiction between shortening ion paths and maintaining electron conduction.
Solution Approach 2:
The patent applies different structural characteristics to different regions: the active material layers are made thin to shorten ion paths, while the conductive framework and current collectors are designed to maintain electron transfer. This local differentiation of structural properties allows simultaneous optimization of both ion and electron transport.
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 design enhances battery characteristics by maintaining high performance regardless of electrode thickness, improving durability and suppressing capacity decrease, while allowing for ultra-thick-film electrodes and increased energy density.
Implementation Method 1
a separating membrane disposed between the first active material fluid and the structure, the separating membrane having ion conducting properties and insulating properties
Implementation Method 2
diffusion in the thickness direction (depth direction) is not taken into consideration
Implementation Method 3
a first active material fluid which is electrically connected to the first electrode, contains a first active material and a supporting salt, and is flowable
Data Source
AI summary
A secondary battery includes a first electrode; a first active material fluid which is electrically connected to the first electrode, contains a first active material and a supporting salt, and is flowable; and a second electrode including a structure which is formed by containing a second active material, the structure either being immersed in the first active material fluid or holding the first active material fluid, and a separating membrane disposed between the first active material fluid and the structure, the separating membrane having ion conducting properties and insulating properties.