Power Storage Device Electrode Viscosity Gradient Water Resistance
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Solution Overview
Problem
Existing power storage devices face degradation due to water intrusion, as the viscosity of the electrolytic solution in the electrode and separator is similar, allowing water to disperse and degrade the device's characteristics.
Innovation Solution
A power storage device configuration with a positive and negative electrode active material layer including an electrolytic solution, a non-crosslinked first polymer compound, and a binder with a different second polymer compound, where the polymer compound is crosslinked in the separator layer, creating a higher viscosity in the active material layers to hinder water diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the viscosity of the electrolytic solution in the electrode and separator is made substantially the same, then the electrolytic solution can flow freely and maintain good ionic conductivity, but water intruding into the power storage device disperses not only in the separator but also in the electrode, degrading device characteristics
Solution Approach 1:
The patent applies local quality by making the viscosity of the electrolytic solution different between the electrode and separator regions. Specifically, the electrolytic solution in the electrode has a viscosity of 10-100 cP, while the electrolytic solution in the separator has a viscosity of 0.1-10 cP. This localized differentiation allows the electrode region to resist water intrusion while the separator maintains good ionic conductivity.
Solution Approach 2:
The patent changes the viscosity parameter of the electrolytic solution between different regions. By controlling the viscosity of the electrolytic solution in the electrode to be higher (10-100 cP) than in the separator (0.1-10 cP), the patent creates a viscosity gradient that prevents water from dispersing into the electrode while maintaining ionic transport in the separator.
2Reliability
If a polymer compound is added to the electrolytic solution in the electrode to increase viscosity, then water diffusion is suppressed, but the complexity of the electrode structure and manufacturing process increases
Solution Approach 1:
The patent uses composite materials by combining the electrolytic solution with a polymer compound in the electrode region. The polymer compound (such as polyethylene oxide or polypropylene carbonate) forms a gel-like structure with the electrolytic solution, increasing viscosity and creating a composite material that resists water intrusion while maintaining ionic conductivity.
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 effectively suppresses water intrusion into the electrodes, maintaining device performance by reducing water diffusion rates and improving manufacturing efficiency and reliability.
Implementation Method 1
a first polymer compound that is not crosslinked... where the polymer compound is crosslinked in the separator layer
Implementation Method 2
forming a gel electrolyte layer by crosslinking the polymer compound included in the paste layer
Data Source
AI summary
A power storage device having a positive electrode including a positive electrode current collector and a positive electrode active material layer, a negative electrode including a negative electrode current collector and a negative electrode active material layer, and a separator layer between the positive electrode and the negative electrode and including a gel electrolyte. At least one of the positive electrode active material layer and the negative electrode active material layer includes an electrode active material, an electrolytic solution, a first polymer compound that is not crosslinked, and a binder having a second polymer compound different from the first polymer compound.