Non-aqueous Battery Gas Discharge via Electrolyte Layer
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Solution Overview
Problem
Non-aqueous electrolyte secondary batteries using aqueous binders in the negative electrode active material layer experience increased gas generation during charge and discharge, leading to decreased battery capacity over time due to water decomposition and uneven SEI film formation, which affects long-term battery performance.
Innovation Solution
The battery design includes a negative electrode active material layer with a density of 1.4 to 1.6 g/cm3 and an electrolyte solution layer between the electrodes, allowing for efficient gas discharge through specifically controlled thickness ratios and gas paths, enhancing gas outgassing and maintaining battery capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an aqueous binder is used in the negative electrode active material layer, then the binding effect is improved and active material ratio is increased, but gas generation increases during charge and discharge
Solution Approach 1:
The patent extracts and removes the harmful gas generated during charge and discharge from the battery system through a dedicated gas discharge path, allowing the aqueous binder to maintain its binding benefits while eliminating the harmful gas accumulation that would otherwise degrade battery performance
Solution Approach 2:
The patent introduces a gas discharge path as an intermediary mechanism between the negative electrode active material layer and the external environment, enabling controlled gas removal without compromising the electrode structure or binding effectiveness
2Strength
If gas generation increases during charge and discharge, then aqueous binder binding effect is maintained, but battery capacity decreases over long period
Solution Approach 1:
The patent extracts harmful gas from the battery system through a dedicated discharge path, preventing gas accumulation that would otherwise increase internal pressure and reduce battery capacity over time, while maintaining the aqueous binder's binding effectiveness
Solution Approach 2:
The patent converts the harmful gas generation side effect into a manageable condition by providing a controlled discharge path, allowing the aqueous binder to continue providing superior binding effects while the gas is harmlessly expelled through the designated path
3Quantity of substance
If the ratio of electrode and separator thickness to total thickness is increased to 0.85 or more, then energy density is improved, but gas discharge space is reduced
Solution Approach 1:
The patent resolves the space conflict by introducing a gas discharge path that utilizes the thickness dimension of the electrolyte solution layer, allowing gas to be discharged vertically through the electrolyte layer without requiring additional lateral space that would compromise energy density
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 reduces gas retention and maintains battery capacity over long periods by facilitating efficient gas discharge, improving the battery's long-term cycle performance and energy density.
Implementation Method 1
an electrolyte solution layer is disposed between at least one layer of the negative electrode active material layer and the positive electrode active material layer, and the separator
Implementation Method 2
the amount of gas generated from the electrode during first time charge and discharge increases than that using an organic binder
Data Source
AI summary
A non-aqueous electrolyte secondary battery allows gas generated when an aqueous binder is used as a binder of a negative electrode active material to be effectively discharged from the electrode, and has small decrease of the battery capacity despite use over a long period of time. The non-aqueous electrolyte secondary battery has a positive electrode active material layer, a negative electrode active material layer, and a separator. The density of the negative electrode active material layer is 1.4 to 1.6 g/cm3, an electrolyte solution layer is disposed between at least one layer of the negative electrode active material layer and the positive electrode active material layer, and the separator, and the ratio of total thickness of the positive electrode, the negative electrode and the separator to total thickness of the positive electrode, the negative electrode, the separator and the electrolyte solution layer, is 0.85 or more and less than 1.0.